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Encyclopedia > List of astronomical topics

This page aims to list articles on Wikipedia that are related to astronomy, astrophysics and cosmology. This is so that those interested in the subject can monitor changes to the pages by clicking on Related changes in the sidebar. Lunar astronomy: the large crater is Daedalus, photographed by the crew of Apollo 11 as they circled the Moon in 1969. ... Spiral Galaxy ESO 269-57 // Astrophysics is the branch of astronomy that deals with the physics of the universe, including the physical properties (luminosity, density, temperature and chemical composition) of astronomical objects such as stars, galaxies, and the interstellar medium, as well as their interactions. ... Cosmology, from the Greek: κοσμολογία (cosmologia, κόσμος (cosmos) world + λογια (logia) discourse) is the study of the universe in its totality and by extension mans place in it. ...


The list is not necessarily complete or up to date - if you see an article that should be here but isn't (or one that shouldn't be here but is), please update the page accordingly.


Three astronomy-related WikiProjects are being developed, please visit WikiProject Astronomical Objects, WikiProject Constellations, and WikiProject Telescopes.

Contents: Top - 0–9 A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

0–9

1 Ceres (, Latin Cerēs) was the first asteroid to be discovered. ... (Redirected from 1P/Halley) Comet Halley as taken with the Halley Multicolor Camera on the ESA Giotto mission. ... The first of NASAs three High Energy Astronomy Observatories, HEAO 1 was launched aboard an Atlas Centaur rocket on 12 August 1977 and operated until 9 January 1979. ... 2 Pallas (pal-us, Greek Παλλάς) was the first asteroid discovered after 1 Ceres. ... European Southern Observatory infrared image of 2M1207 (blueish) and companion planet 2M1207b (reddish), taken in 2004. ... Infrared image of 2M1207 (blueish) and 2M1207b (reddish). ... Observations for the Two Micron All-Sky Survey (2MASS) began in 1997 and were completed in 2001 at two telescopes located one each in the northern and southern hemispheres (Mt. ... Comet Encke (officially designated 2P/Encke) is a periodic comet, named after Johann Franz Encke, who through laborious study of its orbit and many calculations was able to link multiple observations in the years 1786, 1795, 1805 and 1818 to the same object. ... In astronomy, the 2dF Galaxy Redshift Survey (Two-degree-Field Galaxy Redshift Gurvey), or 2dFGRS is a redshift survey conducted by the Anglo-Australian Observatory in the 1990s. ... The Second Cambridge Catalogue of Radio Sources (2C) was published in 1955 by J R Shakeshaft and colleagues. ... 3 Juno (jew-noh) was discovered on September 1, 1804 by German astronomer Karl L. Harding, using a humble 2-inch telescope. ... 3C may refer to the digital radio station of the same name The Third Cambridge Catalog of Radio Sources (3C) is an astronomical catalogue of celestial radio sources as measured at 159-MHz. ... 3C48 was the first source in the Third Cambridge (3C) radio survey for which an optical identification was found (by Allan Sandage in 1960). ... an X-Ray image of 3C58 from the orbiting Chandra X-Ray Observatory. ... 3C273 is a quasar located in the constellation Virgo. ... Comet Biela 3D/Biela is the official designation for a lost periodic comet discovered in 1826 by Wilhelm von Biela. ... The 3. ... 4 Vesta (ves-ta) is the second most massive asteroid in the asteroid belt, with a mean diameter of about 530 km and an estimated mass 12% the mass of the entire asteroid belt. ... The Fourth Cambridge Survey (4C) is an astronomical catalogue of celestial radio sources as measured at 178 MHz using the 4C Array. ... The 4C Array is a cylindrical paraboloid radio telescope at the Mullard Radio Astronomy Observatory, similar in design to the Molonglo Observatory Synthesis Telescope. ... 5 Astraea (as-tree-a; written Astræa in the early scientific litterature) is a large main belt asteroid. ... The Fifth Cambridge Survey of Radio Sources (5C) is an astronomical catalogue of celestial radio sources as measured at 408-MHz and 1407-MHz. ... 6 Hebe (hee-bee, Greek ‘Ήβη) is a very large Main belt asteroid. ... The 6C Survey of radio sources (6C) is an astronomical catalogue of celestial radio sources as measured at 151-MHz. ... The Eighth Cambridge Survey (8C) is an astronomical catalogue of celestial radio sources as measured at 38-MHz. ... The Nineth Cambridge Catalog of Radio Sources (9C) is an astronomical catalogue of celestial radio sources as measured at 15-GHz. ... Tempel 1 is a periodic comet (formally designated 9P/Tempel 1). ... 10 Hygiea (hye-jee-a or hi-jee-a) is the fourth largest Main belt asteroid with a diameter of 407 km. ... 12P/Pons-Brooks is the designation for a periodic comet with a period of 71 years. ... 14 Herculis is a star with a planet orbiting around it, making it a planetary system. ... 15 Eunomia (ew-noh-mee-a) is the 12th largest Main belt asteroid. ... 16 Cygni is a double star system 69. ... 16 Psyche (sye-kee) is the 13th-largest Main belt asteroid, measuring 250 kilometers in diameter. ... 20 Massalia is a large and fairly bright Main belt asteroid. ... 21 Lutetia (loo TET ee a) is a large Main belt asteroid, about 100 kilometers in diameter. ... Comet Giacobini-Zinner was discovered by Michel Giacobini (Nice, France) in Aquarius on December 20, 1900. ... 24 Themis (thee-mis, them-is) is one of the largest Main belt asteroids. ... 25 Phocaea (fo-see-a) is a Main belt asteroid. ... The comet Schwassmann-Wachmann 1 Source: Nasa Comet Schwassmann-Wachmann 1 is thought to be a member of a relatively new class of objects called Centaur, of which 45 objects are known. ... 31 Euphrosyne (you FRO sai ne) is one of the largest main belt asteroids. ... Adjective Uranian Atmospheric characteristics Atmospheric pressure 120 kPa (at the cloud level) Hydrogen 83% Helium 15% Methane 1. ... 40 Eridani (also known as Omicron 2 Eridani, or Keid, from the Arabic word qayd (egg) shells) is a triple star system less than 16. ... 43 Ariadne (air-ee-ad-nee) is a fairly large and bright main belt asteroid. ... 44 Nysa (NEE sa) is a quite large and very bright main belt asteroid. ... 45 Eugenia (ew-jee-nee-a) is a large Main belt asteroid. ... 47 Ursae Majoris (abbreviated 47 UMa) is a 5th magnitude yellow dwarf star in the constellation of Ursa Major. ... 48 Doris (dor-is, Greek Δωρις) is one of the largest main belt asteroids. ... 51 Pegasi (Flamsteed designation, HIP 113357 in the Hipparcos Catalogue, HD 217014 in the Henry Draper Catalogue) is the name of a Sun-like star 14. ... 51 Pegasi b (also written as 51 Peg b) is the first planet discovered around a sun-like star outside of the solar system. ... 51 Pegasi b (also written as 51 Peg b) is the first planet discovered around a sun-like star outside of the solar system. ... 52 Europa, diameter 289 km, was discovered on February 4, 1858 by H. Goldschmidt. ... 55 Cancri (abbreviated 55 Cnc; Bayer designation ρ1 Cancri, Rho-1 Cancri) is a nearby 6th magnitude star in the constellation Cancer. ... Comet Tempel-Tuttle (formally designated as 55P/Tempel-Tuttle) was independently discovered by Ernst Tempel on December 19, 1865 and by Horace Parnell Tuttle on January 6, 1866. ... 61 Cygni is a star in the constellation Cygnus. ... 61 Cygni is a star in the Cygnus constellation. ... 61 Cygni is a star in the Cygnus constellation. ... 65 Cybele is one of the largest asteroids in the main belt. ... 67P/Churyumov-Gerasimenko is the designation of a comet with a current orbital period of 6. ... 70 Virginis (also designated HD 217014 and SAO 090896, HR 5072) is a main sequence star in the constellation Virgo. ... 71 Niobe is a quite large main belt asteroid. ... An enhanced image of Comet 81P/Wild, from the Stardust spacecraft, showing surface detail and plumes of gas. ... 87 Sylvia (sil-vee-a) is one of the largest main belt asteroids. ... 90 Antiope (an-tye-a-pee) is an asteroid discovered on October 1, 1866 by Robert Luther. ... 92 Undina is a large main belt asteroid. ... 93 Minerva is a large main belt asteroid. ... 94 Aurora is one of the largest main belt asteroids. ... 95 Arethusa is a large main belt asteroid. ... 106 Dione is a large main belt asteroid. ... 107 Camilla is one of the largest main belt asteroids. ... 110 Lydia is a quite large Main belt asteroid composed of fairly pure nickel-iron. ... 153 Hilda is an very large asteroid orbiting in outermost Main belt. ... 154 Bertha is a very dark and very large outer Main belt asteroid. ... 221 Eos is a rather large Main belt asteroid. ... NASA image of 243 Ida. ... 253 Mathilde is a Main belt asteroid that was visited by the NEAR Shoemaker spacecraft on its way to asteroid 433 Eros. ... 279 Thule is a very large Main belt asteroid. ... 323 Brucia was the first asteroid to be discovered by the use of astrophotography. ... 324 Bamberga is the 16th largest asteroid in the Main asteroid belt. ... 342 Endymion is a large Main belt asteroid. ... The asteroid 433 Eros (eer-os) was named after the Greek god of love Eros. ... 434 Hungaria is a relatively small Main belt asteroid. ... 451 Patientia is an asteroid. ... 511 Davida is a main belt asteroid. ... 588 Achilles is an asteroid discovered on February 22, 1906 by the German astronomer Max Wolf. ... 624 Hektor is the largest of the Jovian Trojan asteroids. ... 674 Rachele 674 Rachele is a minor planet orbiting the Sun. ... 704 Interamnia (IN ter AM nia) is a very large asteroid with a diameter of 350 kilometres. ... 944 Hidalgo is an unusual asteroid, and has the longest orbital period (13. ... 951 Gaspra is an S-type asteroid that orbits in the inner edge of the asteroid belt. ... 1036 Ganymed is the largest Amor asteroid. ... 1221 Amor is the namesake of the Amor asteroids, a group of near-Earth asteroids whose orbits range between those of Earth and Mars. ... 1566 Icarus is an Apollo asteroid (a sub-class of near-Earth asteroid) whose unusual characteristic is that at perihelion it is closer to the Sun than Mercury; it is said to be a Mercury-crosser asteroid. ... 3D computer model of the different faces of Geographos. ... Toro (1948 OA) is the asteroid with the number 1685. ... 1862 Apollo is a Q-type asteroid, discovered by Karl Reinmuth in 1932, but lost and not recovered until 1973. ... 2001 QR322 (also written 2001 QR322) is an asteroid discovered in 2001 that is one of the two currently known Trojan asteroid of Neptune (the other is 2004 UP10). ... The title of this article is incorrect due to technical limitations. ... 2003 UB313 is a trans-Neptunian object (TNO) believed to be larger than the planet Pluto. ... 2004 AS1 (also written 2004 AS1), also known by the temporary name AL00667, is a near-Earth asteroid, first discovered on January 13, 2004, by the LINEAR project. ... 2005 FY9 (also written 2005 FY9), codenamed Easterbunny by its discoverers, is a very large Kuiper belt object discovered on March 31, 2005 by the team led by Michael Brown. ... 2060 Chiron (IPA: ) is an object in the outer solar system with an orbit between those of Saturn and Uranus and a radius of 71±5 km [1]. Although it was initially classified as an asteroid, later dispute arose as to whether it was an asteroid or actually a comet. ... 2062 Aten is an asteroid that was discovered at the Palomar Mountain Observatory by Eleanor F. Helin, who is now the principal scientist for the NEAT (Near-Earth Asteroid Tracking) project. ... 3D model of Asteroid 2063 Bacchus (Scott Hudson) The Apollo, Venus- and Mars-crosser asteroid 2063 Bacchus was discovered on April 24, 1977 by Charles T. Kowal at the Palomar Observatory. ... 3001 Michelangelo is a small main belt asteroid, which was discovered by Edward L. G. Bowell in 1982. ... 3018 Godiva is a small main belt asteroid, which was discovered by Edward L. G. Bowell in 1982. ... 3200 Phaethon (sometimes incorrectly spelled Phaeton) is an Apollo and Mercury-, Venus- and Mars_crosser asteroid with unusual properties, and may be an extinct comet. ... 3467 Bernheim is an asteroid. ... 3753 Cruithne (English crew-een-ya; Modern Irish crih-na) is an asteroid in orbit around the Sun. ... 3834 Zappafrank is a small main belt asteroid. ... The asteroid 4179 Toutatis (too-ta-tis) is an Apollo, an Alinda and a Mars-crosser asteroid with a chaotic orbit produced by a 3:1 resonance with the planet Jupiter. ... The asteroid 4593 Reipurth was discovered on March 16, 1980, by Claes-Ingvar Lagerkvist. ... The asteroid 4769 Castalia (previously known by the provisional designation 1989 PB) was the first asteroid to be directly imaged. ... 5145 Pholus (FOE luss) is a Centaur in an eccentric orbit, with a perihelion near the orbit of Saturn and aphelion near the orbit of Neptune. ... 5261 Eureka was discovered at Mt Palomar on June 20, 1990 and turned out to be the first known Mars Trojan asteroid. ... Image of 5535 Annefrank taken by the Stardust space probe 5535 Annefrank is an inner main belt asteroid, and member of the Augusta family. ... To meet Wikipedias quality standards, this article or section may require cleanup. ... The Main belt asteroid 11169 Alkon was discovered by the Lincoln Laboratory at the Massachusetts Institute of Technology. ... 18610 Arthurdent is a small main belt asteroid. ... (28978) Ixion (ik·sye·un) is a Kuiper belt object discovered on May 22, 2001 with a diameter of < 822 km and a semimajor axis of about 39. ... Artists impression by G. Bacon of STScI / NASA 50000 Quaoar (pronounced kwah·war, kwah·wor, or kwow·ur, Tongva ) [1] is a Trans-Neptunian object orbiting the Sun in the Edgeworth-Kuiper belt. ... 90377 Sedna is a trans-Neptunian object, discovered by Michael Brown (Caltech), Chad Trujillo (Gemini Observatory) and David Rabinowitz (Yale University) on November 14, 2003. ... 90482 Orcus (originally known by the provisional designation 2004 DW) is a Kuiper Belt object (KBO) that was discovered by Michael Brown of Caltech, Chad Trujillo of the Gemini Observatory, and David Rabinowitz of Yale University. ... Close approach of Apophis on April 13, 2029 The white bar indicates uncertainty in the range of positions 99942 Apophis (previously better known by its provisional designation 2004 MN4) is a Near-Earth asteroid that caused a brief period of concern in December 2005 because initial observations indicated a relatively...

A

A New Theory of Magnetic Storms is a 1931 book by Chapman and Ferraro which sought to explain the phenomenon of geomagnetic storms. ... A-type asteroids are inner-belt asteroids that have a strong, broad 1 µm olivine feature and a very reddish spectrum shortwards of 0. ... Marc Aaronson (August 24, 1950 in Los Angeles - April 30, 1987 in Tucson, Arizona) was an American astronomer. ... Chalid Ben Abdulmelik was an Arab astronomer of the 9th century. ... George Ogden Abell (March 1, 1927 – October 7, 1983) was an astronomer at UCLA who is best known for his catalogue of clusters of galaxies. ... This article needs to be cleaned up to conform to a higher standard of quality. ... Aberration of light (also referred to as astronomical aberration or stellar aberration) is an astronomical phenomenon defined as an apparent motion of the heavenly bodies; stars describing more or less elliptic annual orbits, according to the latitude of the star; consequently at any moment the star appears to be displaced... In astronomy, absolute magnitude is the apparent magnitude, m, an object would have if it were at a standardized distance away. ... In astronomy, absolute magnitude is the apparent magnitude, m, an object would have if it were at a standard luminosity distance away from us. ... Accelerating universe is a term for the idea that our universe is undergoing divergent rapid expansion. ... Artists conception of a binary star system with one black hole and one main sequence star // Overview An accretion disc (or accretion disk) is a structure formed by material falling into a gravitational source. ... An accretion disc (or accretion disk) is a structure formed by material falling into a gravitational source. ... The position of Achernar Achernar (α Eri / α Eridani / Alpha Eridani) is the brightest star in the constellation Eridanus and the ninth brightest star in the nighttime sky. ... An Achondrite is a stony meteorite that is made of material similar to terrestrial basalts or plutonic rocks. ... This is about the optical device. ... This is about the optical device. ... Acrux (α Cru / α Crucis / Alpha Crucis) is the brightest star in constellation Crux (the Southern Cross) and the thirteenth brightest star in the nighttime sky, at visual magnitude 0. ... An active galaxy is a galaxy where a significant fraction of the energy output is not emitted by the normal components of a galaxy: stars, dust and interstellar gas. ... An active galaxy is a galaxy where a significant fraction of the energy output is not emitted by the normal components of a galaxy: stars, dust and interstellar gas. ... Active optics is a relatively new technology for reflecting telescopes. ... John Couch Adams (June 5, 1819 – January 21, 1892), was a British mathematician and astronomer. ... A deformable mirror can be used to correct wavefront errors in an astronomical telescope. ... Adara can be a misspelling of: Adhara, the binary star in the constellation Canis Major Adara can also refer to: Adara (porn star), who starred in the pornographic movie, Busty Naturals as Adara Star. ... Adelard of Bath was a 12th century English scholar. ... Adhara (ε CMa / ε Canis Majoris / Epsilon Canis Majoris), is the second brightest star in the constellation Canis Major, and one of the brightest stars in the nighttime sky. ... Adler Planetarium The Adler Planetarium and Astronomy Museum in downtown Chicago, Illinois was the first planetarium in the United States and is the oldest in existence today. ... Atmospheric pressure 0 kPa Adrastea (IPA: , ad-ra-stee-a, Greek Αδράστεια) is the second of Jupiters known moons (counting outward from the planet). ... ASCA (formerly named Astro-D) is Japans fourth cosmic X-ray astronomy mission, and the second for which the United States is providing part of the scientific payload. ... The aether (also spelled ether) is a substance concept, historically used in science and philosophy. ... The luminiferous aether: it was hypothesised that the Earth moves through a medium of aether that carries light In the late 19th century the luminiferous aether (light-bearing aether), or ether, was a substance postulated to be the medium for the propagation of light. ... AfterGlow (band) Left-Right, Joe Hudson, Alex Boba, Will Hardcastle, Ben Elseworthy, Alex Ruckledge. ... The Akeno Giant Air Shower Array (AGASA) is a very large surface array designed to study the origin of ultra-high energy cosmic rays. ... Based on extensive scientific research, the age of the Earth is around 4. ... Nothing is certain as to the extent of either the age or size of the universe, but the age of the Universe, according to the Big Bang theory, is defined as the largest possible value of proper time integrated along a timelike curve from the Earth at the present epoch... The Astronomical Image Processing System provides facilities for calibration, editing, image formation, image enhancement, and analysis of images and other astronomical data. ... The airglow is the very weak emission of visible light by the earths atmosphere, which means that the night sky is never completely dark. ... A computer generated image of an Airy Disc. ... George Biddell Airy Sir George Biddell Airy (July 27, 1801–January 2, 1892) was British Astronomer Royal from 1835 to 1881. ... Robert Grant Aitken (December 31, 1864 – October 29, 1951) was an American astronomer. ... Al Sufi from The Depiction of Celestial Constellations Abd Al-Rahman Al Sufi (December 7, 903 – May 25, 986) was a Persian astronomer also known as Abd ar-Rahman as-Sufi, or Abd al-Rahman Abu al-Husain, and known in the west as Azophi. ... Al Sufi from The Depiction of Celestial Constellations Abd Al-Rahman Al Sufi ( December 7, 903 – May 25, 986) was a Persian astronomer also known as Abd ar-Rahman as-Sufi, or Abd al-Rahman Abu al-Husain, and known in the west as Azophi. ... Al Battani (ca. ... Khwarizmi comemmorated on this Soviet stamp. ... Al Battani (ca. ... Albedo is the measure of reflectivity of a surface or body. ... Albert Abraham Michelson. ... Albiorix (al-bee-or-iks) is a natural satellite of Saturn. ... Albireo (β Cyg / β Cygni / Beta Cygni) is the third brightest star in the constellation Cygnus. ... Mizar (ζ UMa / ζ Ursae Majoris / Zeta Ursae Majoris) is a star in the constellation Ursa Major, lying just at the corner of the Big Dippers handle. ... Comparison between Aldebaran and the Sun Aldebaran, (α Tau / α Tauri / Alpha Tauri), is the brightest star in the constellation Taurus and one of the brightest stars in the nighttime sky. ... Stained glass window showing Aldhelm, installed in Malmesbury Abbey in 1928 in memory of Rev. ... The Alfonsine tables were astronomical tables drawn up at Toledo by order of Alfonso X in 1252 to correct the anomalies in the Ptolemaic tables; they divided the year into 365 days, 5 hours, 49 minutes, 16 seconds. ... Alfonso X and his court. ... Hannes Olof Gösta Alfvén (May 30, 1908; Norrköping, Sweden - April 2, 1995; Djursholm, Sweden) was a Swedish electrical power engineer. ... Algieba Algieba is a binary star system in the Leo constellation. ... ALGOL (short for ALGOrithmic Language) is a family of imperative computer programming languages originally developed in the mid 1950s which became the de facto standard way to report algorithms in print for almost the next 30 years. ... meteorite fragment ALH84001 ALH84001 (Allen Hills, 1984 #001) is a meteorite found in Allen Hills, Antarctica in December 1984 by a team of US meteorite hunters from the ANSMET project. ... Alioth, Epsilon Ursae Majoris, is the brightest star in the constellation Ursa Major and, at magnitude 1. ... Alkaid (also known as Elkeid, Benetnash or Benetnasch: Bayer designation η Ursae Majoris) is a star in the constellation Ursa Major. ... The Allegheny Observatory was founded on February 15, 1859 in the city of Allegheny, Pennsylvania. ... Almach (γ1 Andromedae) is a multiple star also known by the names Almaach, Almak, Alamak, HR 603, and HR 12533. ... Almagest is the Latin form of the Arabic name (al-kitabu-l-mijisti, i. ... Alnilam, also known as ε Orionis or 46 Orionis, is a large blue star in the constellation of Orion. ... This article needs to be cleaned up to conform to a higher standard of quality. ... The name Alniyat is associated with two stars in the constellation of Scorpius. ... Alpha Andromedae (α And / α Andromedae) is the brightest star in the Andromeda constellation, which is located immediately northwest of Pegasus. ... Alpha Centauri (α Cen / α Centauri) is the brightest star system (a triple star system) in the southern constellation of Centaurus, and contains the fourth brightest star in the night sky, with an apparent visual magnitude of −0. ... Alpha Centauri A is a star of the star system Alpha Centauri. ... Alpha Centauri B (also Rigel Kentaurus B — the foot of the centaur in Arabic) is a star of the Alpha Centauri star system. ... Mirfak (also known as Algenib, and designated α Persei) is the brightest star in the constellation of Perseus. ... The alpha reactions is one of two class of fusion reactions by which stars convert helium into heavier elements, the other being the triple_alpha process. ... In cosmology, the Alpher-Bethe-Gamow theory (or αβγ theory) was created by Ralph Alpher, at the time a physics PhD student, and his advisor George Gamow. ... Alpheratz, or α Andromedae, is the brightest star in the Andromeda constellation, which is located immediately northwest of Pegasus. ... Altair (α Aql / α Aquilae / Alpha Aquilae / Atair ) is the brightest star in the constellation Aquila and the twelfth brightest star in the nighttime sky, at visual magnitude 0. ... An Altazimuth or alt-azimuth mount is a simple mount used for moving a telescope or camera along two perpendicular axes of motion. ... ... Aludra is a star in the constellation Canis Major (Eta Canis Majoris) approximately 3200 light years away. ... Atmospheric pressure 0 kPa Amalthea (am-É™l-thee-É™, IPA: , Greek Αμάλθεια) is the third moon of Jupiter (in order of distance from the planet), and the fifth in order of discovery, hence its Roman numeral designation of Jupiter V. It was discovered on September 9, 1892 by Edward Emerson Barnard using... It has been suggested that this article or section be merged with Skygazing. ... There is a strong tradition of amateur telescope making within the amateur astronomy community. ... The American Astronomical Society (AAS) is a US society of professional astronomers and other interested individuals, headquartered in Washington, DC. The main aim of the AAS is provide a political voice for its members and organise their lobbying. ... Amateur astronomers photo of the North America Nebula The North America Nebula (also known as NGC 7000) is an emission nebula in the Cygnus constellation, close to Deneb (the tail of the swan and its brightest star). ... The Amor asteroids are a group of near-Earth asteroids named after the asteroid 1221 Amor. ... Eusebius Amort (November 15, 1692 - February 5, 1775) was a German Catholic theologian. ... The analemma photographed, looking east in the northern hemisphere. ... Atmospheric pressure 0 kPa Ananke (a-nang-kee, IPA ; Greek Ανάγκη) is one of Jupiters moons. ... The Ananke group is made up of moons of Jupiter which share similar orbits. ... Anaximander Anaximander (Greek: Αναξίμανδρος)(610 BC/609–c. ... Andromeda is a constellation named for the princess Andromeda (which is Greek for Ruler over men), a character in Greek mythology. ... The Andromeda Galaxy (also known as M31 or NGC 224; older texts often call it the Andromeda Nebula) is a giant spiral galaxy in the Local Group, together with the Milky Way galaxy. ... Andronicus of Cyrrhus was a Greek astronomer who flourished about 100 BC. He built a horologium at Athens, the so-called Tower of the Winds, a considerable portion of which still exists. ... The Anglo-Australian Telescope is a 3. ... The angular diameter of an object as seen from a given position is the diameter measured as an angle. ... The angular diameter distance is a distance measure used in astronomy. ... The angular size redshift relation for a Lambda cosmology. ... Angular frequency is a measure of how fast an object is rotating In physics (specifically mechanics and electrical engineering), angular frequency ω (also called angular speed) is a scalar measure of rotation rate. ... This article is about angles in geometry. ... Angular resolution describes the resolving power of a telescope. ... Annibale de Gasparis (April 9, 1819 – March 21, 1892) was an Italian astronomer. ... Annie Jump Cannon (December 11, 1863 – April 13, 1941) was a US astronomer whose cataloguing work was instrumental in the development of contemporary stellar classification. ... In Egyptian mythology, Month is an alternate spelling for Menthu. ... Anomalous cosmic rays (ACRs) are cosmic rays with unexpectedly low energies. ... To meet Wikipedias quality standards, this article or section may require cleanup. ... Antarctic Submillimeter Telescope and Remote Observatory, or AST/RO, is a 1. ... Antares (α Sco / α Scorpii / Alpha Scorpii) is the brightest star in the constellation Scorpius and one of the brightest stars in the nighttime sky. ... A yagi antenna Most simply, an antenna is an electronic component designed to send or receive radio waves. ... In cosmology, the anthropic principle in its most basic form states the truism that any valid theory of the universe must be consistent with our existence as carbon-based human beings at this particular time and place in the universe. ... The constellation Antlia (Latin for pump) is a relatively new constellation as it was only created in the 18th century, being too faint to be acknowledged by the ancient Greeks. ... Antonín Mrkos (January 27, 1918 – May 29, 1996) was a Czech astronomer. ... This article is about several astronomical terms (apogee & perigee, aphelion & perihelion, generic equivalents based on apsis, and related but rarer terms. ... In optics, an aperture is something which restricts the diameter of the light path through one plane in an optical system. ... a) shows a simple experiment using an aperture mask in a re-imaged aperture plane. ... Aperture synthesis is a type of interferometry that mixes signals from a collection instruments to produce measurements having the same angular resolution as an instrument the size of the entire collection. ... This article is about several astronomical terms (apogee & perigee, aphelion & perihelion, generic equivalents based on apsis, and related but rarer terms. ... This article is about several astronomical terms (apogee & perigee, aphelion & perihelion, generic equivalents based on apsis, and related but rarer terms. ... This article is about several astronomical terms (apogee & perigee, aphelion & perihelion, generic equivalents based on apsis, and related but rarer terms. ... Statue of Apollo at the British Museum. ... Apollo 11 was an American space mission, part of the Apollo program and the first manned mission to land on the Moon. ... Apollo 17 was the eleventh manned space mission in the NASA Apollo program, and was the sixth and last mission to date to land on the Moon. ... The Apollo asteroid 25143 Itokawa. ... Description Role: Earth and Lunar Orbit Crew: 3; CDR, CM pilot, LM pilot Dimensions Height: 36. ... The apparent magnitude (m) of a star, planet or other heavenly body is a measure of its apparent brightness; that is, the amount of light received from the object. ... // Headline text HEY!! HOW ARE YOU ALL?? Its nice of you to come read this page. ... Apparent motion is used in at least two senses. ... Solar time is based on the idea that, when the sun reaches its highest point in the sky, it is noon. ... This article is about several astronomical terms (apogee & perigee, aphelion & perihelion, generic equivalents based on apsis, and related but rarer terms. ... A diagram of Keplerian orbital elements. ... Apus (Latin for bird of paradise) is a faint southern constellation, not visible to the ancient Greeks. ... Aquarius (Latin for the Water-bearer or Cup-bearer, symbol , Unicode â™’) is the eleventh sign of the zodiac, situated between Capricornus and Pisces. ... Aquila (Latin for Eagle), is one of the 48 constellations listed by Ptolemy and is now also part of the list of 88 constellations acknowledged by the IAU. It lies roughly at the celestial equator. ... François Jean Dominique Arago (February 26, 1786 – October 2, 1853) was a French mathematician, physicist, astronomer, and politician. ... François Jean Dominique Arago (February 26, 1786 – October 2, 1853) was a French mathematician, physicist, astronomer, and politician. ... Aratus (Greek Aratos) (ca. ... Archaeoastronomy (also spelled Archeoastronomy) is the study of astronomy in an ancient or traditional context, and utilizing archaeological and anthropological evidence. ... Archimedes of Syracuse. ... A minute of arc, arcminute, or MOA is a unit of angular measurement, equal to one sixtieth (1/60) of one degree. ... The long baseline array of AMI, utilizing receivers from the Ryle Telescope. ... A second of arc or arcsecond is a unit of angular measurement which comprises one-sixtieth of an arcminute, or 1/3600 of a degree of arc or 1/1296000 ≈ 7. ... Arcturus (α Boo / α Boötis / Alpha Boötis) is the brightest star in the constellation Boötes, and the third brightest star in the night sky, with a visual magnitude of −0. ... The Arecibo Observatory is located in Arecibo, Puerto Rico on the north coast of the island. ... The Arecibo Observatory is located in Arecibo, Puerto Rico on the north coast of the island. ... The constellation Argo Navis drawn by Johannes Hevelius in 1690 Argo Navis (or simply Argo) was a large southern constellation representing the Argo, the ship used by Jason and the Argonauts in Greek mythology. ... The argument of the perihelion is one of the orbital elements describing the orbit of a planet. ... The argument of the perihelion is one of the orbital elements describing the orbit of a planet. ... Ariane 5 lifts off with the Rosetta probe on 2 March 2004. ... Atmospheric pressure 0 kPa Ariel (air-ee-ul, pronounced ) is a moon of Uranus discovered on 1851-10-24 by William Lassell. ... Aries (Latin for Ram, symbol , Unicode ♈) is one of the constellations of the zodiac. ... The New Greek Telescope project of the AI-NOA for the 2. ... Statue of Aristarchus at Aristoteles University in Thessaloniki, Greece Aristarchus (310 BC - c. ... Aristotle (Ancient Greek: AristotelÄ“s 384 BC – March 7, 322 BC) was an ancient Greek philosopher, who studied with Plato and taught Alexander the Great. ... Krishna to Arjuna: Behold My mystic opulence! Artwork © courtesy of The Bhaktivedanta Book Trust Arjuna (Sanskrit: अर्जुन, arjuna) is one of the heroes of the epic Hindu Mahabharata. ... Armillary sphere An armillary sphere (also known as spherical astrolabe) is a model of the celestial sphere, invented by Eratosthenes in 255 BC. Its name comes from the Latin armilla (circle, bracelet), since it has a skeleton made of graduated metal circles linking the poles and representing the equator, the... Arno Allan Penzias (born April 26, American physicist. ... Halton Arp in London, Oct 2000 Halton Christian Arp is an American astronomer. ... The Array of Low Energy X-ray Imaging Sensors (ALEXIS) X-ray telescopes feature curved mirrors whose multilayer coatings reflect and focus low-energy X-rays or extreme ultraviolet light the way optical telescopes focus visible light. ... Svante August Arrhenius Svante August Arrhenius (February 19, 1859 – October 2, 1927) was a Swedish chemist and one of the founders of the science of physical chemistry. ... Aryabhata (आर्यभट) Ä€ryabhaá¹­a) (476 - 550) is the first of the great mathematician-astronomers of the classical age of India. ... In astronomy, an asterism is a recognized pattern of stars seen in Earths sky which is neither an official constellation nor a true star cluster. ... An asteroid is a small, solid object in our Solar System, orbiting the Sun. ... Image of the main asteroid belt between the orbits of Mars and Jupiter. ... Artists impression of a major impact event. ... 243 Ida and its moon Dactyl An asteroid moon is an asteroid that orbits another asteroid. ... Asteroids are assigned a type based on spectral shape, color, and sometimes albedo. ... Asteroseismology is the study of the internal structure of pulsating stars by the interpretation of their frequency spectra. ... Astigmatism is a refraction error of the eye in which there is a difference in degree of refraction in different meridians. ... Astro-E (NASA) Astro-E2 (NASA) ASTRO-E and ASTRO-EII (or Astro-E2) are Japanese X-ray astronomy satellites built primarily by JAXA. In 2000 the Astro-E launch failed (with the satellite falling into the ocean), so a replacement called Astro-EII was launched on July 10, 2005. ... Astrobiology is an interdisciplinary field, combining aspects of astronomy, biology and geology, which is focused primarily on the study of the origin, distribution and evolution of life. ... Astrochemistry is the study of the chemicals found in outer space, usually in molecular gas clouds, and their formation, interaction and destruction. ... Astrodynamics is the study of the motion of rockets, missiles, and space vehicles, as determined from Sir Isaac Newtons laws of motion and his law of universal gravitation. ... A 16th century astrolabe. ... An astrometric binary star is a binary star for which only one of its component stars could be visually observed. ... This article does not cite its references or sources. ... Astronautics is the branch of engineering that deals with machines designed to work outside of Earths atmosphere, whether manned or unmanned. ... An astronomer or astrophysicist is a scientist whose area of research is astronomy or astrophysics. ... Astronomer Royal is a senior post in the Royal Household of the Sovereign of the United Kingdom. ... An astronomer or astrophysicist is a scientist whose area of research is astronomy or astrophysics. ... Astronomy, which etymologically means law of the stars, (from Greek: αστρονομία = άστρον + νόμος) is a science involving the observation and explanation of events occurring outside Earth and its atmosphere. ... The Astronomical Journal is a monthly scientific journal published by the University of Chicago Press on behalf of the American Astronomical Society. ... Astronomical year numbering is another method of designating BC/AD years. ... The Astronomical Society of the Pacific (ASP) was founded in San Francisco in 1889. ... The astronomical unit (AU or au or a. ... Aberration of light (also referred to as astronomical aberration or stellar aberration) is an astronomical phenomenon defined as an apparent motion of the heavenly bodies; stars describing more or less elliptic annual orbits, according to the latitude of the star; consequently at any moment the star appears to be displaced... See lists of astronomical objects for a list of the various lists of astronomical objects in Wikipedia. ... An astronomical catalog is a list or tabulation of astronomical objects, typically grouped together because they share a common type, morphology, origin, means of detection, or method of discovery. ... Conjunction is a term used in positional astronomy and astrology. ... Astronomical distances are simply so massively huge as to defy the imagination and boggle the mind. ... An astronomical interferometer or hypertelescope is an array of telescopes or mirror segments acting together to probe structures on higher resolutions. ... In ancient times, only the Sun and Moon, a few hundred stars and the most easily visible planets had names. ... See also Lists of astronomical objects Category: ... Opposition is a term used in positional astronomy and astrology. ... Schematic diagram illustrating how optical wavefronts from a distant star may be perturbed by a turbulent layer in the atmosphere. ... There are numerous groups devoted to promoting astronomy research and education. ... High resolution spectrum of the Sun showing thousands of elemental absorption lines (fraunhofer lines). ... Deimos transits the Sun, as seen by Mars Rover Opportunity on March 4, 2004 The word transit has two meanings in astronomy: A transit is the astronomical event that occurs when one celestial body appears to move across the face of another celestial body, as seen by an observer at... The astronomical unit (AU or au or a. ... Astronomical year numbering is based on BCE/CE (or BC/AD) year numbering, but follows normal decimal integer numbering more strictly. ... Lunar astronomy: the large crater is Daedalus, photographed by the crew of Apollo 11 as they circled the Moon in 1969. ... Astronomy and Astrophysics (often referred to as A&A) is a European Journal, publishing papers on theoretical, observational and instrumental astronomy and astrophysics. ... Astrophotography is a specialised type of photography that entails making photographs of astronomical objects in the night sky such as planets, stars, and deep sky objects such as star clusters and galaxies. ... The Astrophysical Journal is one of the foremost research journals devoted to recent developments, discoveries, and theories in astronomy and astrophysics. ... An astrophysicist is a person whose profession is astrophysics. ... Spiral Galaxy ESO 269-57 // Astrophysics is the branch of astronomy that deals with the physics of the universe, including the physical properties (luminosity, density, temperature and chemical composition) of astronomical objects such as stars, galaxies, and the interstellar medium, as well as their interactions. ... The NASA Astrophyiscs Data System (also known as ADS, adswww, or adsabs) is an online database of all peer reviewed and some submitted astronomy articles. ... The Asymptotic Giant Branch is the name given to a region of the Hertzsprung-Russell Diagram populated by evolving low to medium-mass stars. ... ALMAs logo The Atacama Large Millimeter Array (ALMA) is an international astronomy project that consists of a system of radio telescopes in an array formation, located in the Atacama desert in northern Chile. ... Aten is a creator of the universe in ancient Egyptian mythology, usually regarded as a sun god represented by the suns disk. ... The Aten asteroids are a group of near-Earth asteroids, named after the first of the group to be discovered (2062 Aten, discovered January 7, 1976 by Eleanor F. Helin). ... Athena is a name that has stood for figures in mythology and fiction. ... Robert dEscourt Atkinson (April 11, 1898 – October 28, 1982) was an astronomer, physicist and inventor. ... Atmospheric pressure 0 kPa Atlas (at-lus, Greek Άτλας) is a moon of Saturn. ... Atmosphere is the general name for a layer of gases that may surround a material body of sufficient mass. ... Alpha Trianguli Australis (α TrA / α Trianguli Australis) is a star in the constellation Triangulum Australe. ... An aura is: Aura (paranormal), a paranormal effect. ... Auriga (Latin for chariot) is a northern constellation. ... Aurora borealis Polar aurorae are optical phenomena characterized by colorful displays of light in the night sky. ... The Australia Telescope, also known as the Australia Telescope Compact Array is a radio telescope at the Paul Wild Observatory, 25 kilometres west of the town of Narrabri, Australia. ... The Automated Patrol Telescope (APT) is a wide-field CCD imaging telescope, which is operated by the University of New South Wales at Siding Spring Observatory, Australia. ... Illumination of Earth by Sun on the day of equinox The autumnal equinox (or fall equinox) occurs during the month of September in the Northern Hemisphere, and during March in the Southern Hemisphere. ... Auva (δ Virgo) is a red giant star in the constellation Virgo. ... The orbital speed of a body, generally a planet, a natural satellite, an artificial satellite, or a multiple star, is the speed at which it orbits around the barycenter of a system, usually around a more massive body. ... Avior is the star Epsilon Carinae. ... Axial tilt is an astronomical term regarding the inclination angle of a planets rotational axis in relation to its orbital plane. ... The axis of rotation of a rotating body is a line such that the distance between any point on the line and any point of the body remains constant under the rotation. ... Azimuth is the horizontal component of a direction (compass direction), measured around the horizon toward the East, i. ...

B

B-type asteroid is a subdivision of C-type asteroids distinguished spectrally by differences in the ultraviolet absorption. ... Wilhelm Heinrich Walter Baade (March 24, 1893 - June 25, 1960) was a German astronomer who emigrated to the USA in 1931. ... In astronomy, background commonly refers to the incoming light from an apparently empty part of the night sky. ... Background radiation is the ionizing radiation from several natural radiation sources: sources in the Earth and from those sources that are incorporated in our food and water, which are incorporated in our body, and in building materials and other products that incorporate those radioactive sources; radiation sources from space (in... Statue of Roger Bacon in the Oxford University Museum Roger Bacon (c. ... The Baháí calendar, common to the Baháí Faith, is a solar calendar with regular years 365 days long and leap years 366 days long as explained within the Kitáb-i-Aqdas. ... John N. Bahcall (born December 30, 1934) is an American astrophysicist. ... John Bainbridge (1582 – November 3, 1643) was an English astronomer. ... Prof. ... The privileges and statutes of the city of Krakow and its guilds were collected in the 1505 Balthasar Behem Codex, named for the chancellor at the time. ... Benjamin Banneker cartoon by Charles Alston, 1943. ... Barnards star is a star in the constellation Ophiuchus which is notable for having the largest proper motion (10. ... Edward Emerson Barnard (December 16, 1857 – February 6, 1923) was an American astronomer. ... NGC 1300, viewed nearly face-on. ... The Barringer Crater, also known as the Meteor Crater, is a famous impact crater created by a meteorite, located about 55 kilometers east of Flagstaff in the northern Arizona desert (USA). ... In 1911, Edgar Rice Burroughs, now best known as the creator of the character Tarzan, began his writing career with A Princess of Mars, a rousing tale of pulp adventure on the planet Barsoom or Mars. ... The barycenter (from the Greek βαρύκεντρον) is the center of mass of two or more bodies which are orbiting each other, and is the point around which both of them orbit. ... Baryogenesis is the generic designation for the physical processes that generate matter (more specifically, a class of fundamental particle called baryon) from an otherwise matter-empty state (such as it is generally believed to be the state of the Universe at its onset, the so-called Big Bang). ... In particle physics, the baryons are a family of subatomic particles including the proton and the neutron (collectively called Greek barys, meaning heavy, as they are heavier than the other main groups of particles. ... Many of the brighter stars are given names which are known as Bayer designations. ... Johann Bayer (1572 – March 7, 1625) was a German astronomer. ... Be X-ray binaries are a class of High-mass X-ray binaries that consist of a Be star and a neutron star. ... A Be star is a B-type star with prominent emission lines in its spectrum. ... Becrux (β Cru / β Crucis / Beta Crucis) is the second brightest star in the constellation Crux and one of the one of the brightest stars in the nighttime sky. ... List of Behenian Stars Caput Algol (Algols head, associated with the head of Gorgona), Pleiades (actually, several stars), Aldebaran, Alhayhoch, Canis Maior (actually, a constellation, like the next one), Canis Minor, Cor Leonis (Hearth of the Lion), Cauda Urse (Tail of the Bear), Ala Corvi (Wing of the crow... Jacob David Bekenstein (born May 1, 1947), in Mexico City, has contributed to the foundation of black hole thermodynamics and to other aspects of the connections between information and gravitation. ... Atmospheric pressure 0 kPa Belinda (be-lin-da) is a moon of Uranus. ... Jocelyn Bell Burnell (born Jocelyn Bell, 15 July 1943), British astrophysicist who discovered the first radio pulsars with her thesis advisor Antony Hewish. ... Bellatrix (γ Ori / γ Orionis / Gamma Orionis) is the third brightest star in the constellation Orion and the twenty-second brightest star in the nighttime sky. ... BeppoSAX was an Italian-Dutch satellite for X-ray astronomy. ... The Berlin Observatory has its origins in 1700 when Gottfried Leibniz initiated the Brandenburgische Society which would later become Prussian Academy of Sciences. ... Sir Bernard Lovell (born 1913) is a British radio astronomer, director (until 1981) of the Jodrell Bank Observatory. ... Jakob Bernoulli. ... Johann Bernoulli Johann Bernoulli (Basel, July 27, 1667 - January 1, 1748) was a Swiss mathematician. ... Friedrich Wilhelm Bessel (July 22, 1784 – March 17, 1846) was a German mathematician, astronomer, and systematizer of the Bessel functions (which, despite their name, were discovered by Daniel Bernoulli). ... Beta Centauri (β Cen / β Centauri), also known as Hadar or Agena, is the second brightest star in the constellation Centaurus and the eleventh brightest star in the nighttime sky. ... Beta Pictoris is the second brightest star in the constellation Pictor. ... Hubble UV picture of Betelgeuse. ... According to the Big Bang theory, the universe originated in an infinitely dense and physically paradoxical singularity. ... Bianca orbiting Uranus There is also an asteroid called 218 Bianca. ... According to the Big Bang theory, the universe emerged from an extremely dense and hot state (bottom). ... In cosmology, Big Bang nucleosynthesis (alternately: Primordial nucleosynthesis) refers to the production of nuclei other than H-1, the normal, light hydrogen, during the early phases of the universe, shortly after the Big Bang. ... Big Bear Solar Observatory (BBSO) is an astronomical observatory owned and operated by New Jersey Institute of Technology. ... In cosmology, the Big Crunch is a hypothesized collapse of the universe upon itself after its expansion eventually stops — a counterpart to the Big Bang. ... Ursa Major is a constellation visible throughout the year in the northern hemisphere. ... The Big Rip is a cosmological hypothesis about the ultimate fate of the Universe, in which the elements of the universe, from galaxies to atoms, are progressively torn apart by the expansion of the universe. ... According to the Big Bang theory, the universe emerged from an extremely dense and hot state (bottom). ... The term binary asteroid refers to a system in which two asteroids orbit their common centre of gravity, in analogy with binary stars. ... A binary star system consists of two stars both orbiting around their barycenter. ... A binary system is an astronomy term referring to two objects in space, usually stars, which are so close that their gravitational forces attract one another into a mutual orbit. ... Binoculars Binocular telescopes, or binoculars, are two identical or mirror-symmetrical telescopes mounted side-by-side and aligned to point accurately in the same direction, one to be viewed through each of the users eyes. ... A BL Lac object or BL Lacertae object or BL Lac is a type of galaxy with an active galactic nucleus (AGN), making it a type of active galaxy. ... As the temperature decreases, the peak of the black body radiation curve moves to lower intensities and longer wavelengths. ... A black dwarf is a theoretical astronomical object, constituting the remains of a Sun-sized star which has fused all of its original hydrogen and helium fuel to heavier elements such as carbon, oxygen and nitrogen and subsequently lost its remaining energy due to radiation. ... A black hole is a concentration of mass great enough that the force of gravity prevents anything past its event horizon from escaping it except through quantum tunnelling behaviour (known as Hawking Radiation). ... In physics a special field has been created entirely centered around the thermodynamics of black holes. ... This article is about the astronomical body. ... A blazar is a galaxy with a very compact and highly variable energy source at the center of the host galaxy. ... The Reverend Nathaniel Bliss (28 November 1700-2 September 1764) was a noted English astronomer of the 18th century, serving as Astronomer Royal between 1762 and 1764. ... In astronomy, a blue giant is a star with a spectral type of O or B and class of III (giant). ... Blue stragglers are stars in open or globular clusters that are hotter and bluer than other cluster stars having the same luminosity. ... Boötes, a name deriving from Egypt, is one of the 88 modern constellations and was also one of the 48 constellations listed by Ptolemy. ... Johann Elert Bode Johann Elert Bode (January 19, 1747 – November 23, 1826) was a German astronomer known for his contribution to the Titius-Bode law and his works to determine the orbit of Uranus, for which he also suggested the name. ... The Bohr model of the atom In 1913, Niels Bohr introduced what has become known as the Bohr model of the atom to atomic physics. ... Niels Bohr Niels (Henrik David) Bohr (October 7, 1885 – November 18, 1962) was a Danish physicist who made essential contributions to understanding atomic structure and quantum mechanics. ... A bolometer is a device for measuring incident electromagnetic radiation. ... In astronomy, absolute magnitude is the apparent magnitude, m, an object would have if it were at a standardized distance away. ... János Bolyai (December 15, 1802–January 27, 1860) was a Hungarian mathematician. ... Professor Sir Hermann Bondi, KCB , FRS (1 November 1919–10 September 2005) was a British (formerly Austrian) mathematician and cosmologist. ... William Cranch Bond William Cranch Bond (September 9, 1789 – January 29, 1859) was an American astronomer, and the first director of Harvard College Observatory. ... In astronomy, many stars are referred to simply by catalogue numbers. ... The Boomerang Nebula. ... Lewis Boss (1846–1912) was an American Astronomer. ... Boötes, a name deriving from Egypt, is one of the 88 modern constellations and was also one of the 48 constellations listed by Ptolemy. ... James Bradley (1693 – July 13, 1762) was an English astronomer, Astronomer Royal from 1742. ... Tycho Brahe (help· info) , born Tyge Ottesen Brahe (December 14, 1546 – October 24, 1601), was a Danish (Scanian) nobleman astronomer as well as an astrologer and alchemist. ... Branes are objects in M-theory and its offshoot, brane cosmology. ... Brane cosmology is a protoscience motivated by, but not rigorously derived from, superstring theory and M-theory. ... Brera Observatory is an astronomical observatory. ... Brett J. Gladman is a Canadian astronomer and an Associate Professor at the University of British Columbias Department of Physics and Astronomy, in Vancouver, British Columbia. ... The Orion Nebula, a famous reflection nebula. ... Brightness is an attribute of visual perception in which a source appears to emit a given amount of light. ... The Broad Band X-ray Telescope (BBXRT) was flown on the space shuttle Columbia (STS-35) on 1990 December 2-December 11, as part of the ASTRO-1 payload. ... Brocchis Cluster, also know as Collinder 399 or The Coathanger, is an asterism located in the constellation Vulpecula. ... Louis-Victor-Pierre-Raymond, 7th duc de Broglie, generally known as Louis de Broglie (August 15, 1892–March 19, 1987), was a French physicist and Nobel Prize laureate. ... This brown dwarf (smaller object) orbits the star Gliese 229, which is located in the constellation Lepus about 19 light years from Earth. ... Dr. Michael (Mike) E. Brown has been an associate professor of planetary astronomy at the California Institute of Technology (Caltech) since 2002. ... Robert Hanbury Brown was a British astronomer and physicist born 31 August 1916 in Aruvankadu, India. ... The Catherine Wolfe Bruce gold medal is awarded every year by the Astronomical Society of the Pacific for outstanding lifetime contributions to astronomy. ... Albert Blar Brudzewski, Wojciech Brudzewski, Albert of Brudzewo in Masovia (Latin Albertus de Brudzewo) (1445_1497) Polish astronomer and mathematician, a prominent professor at the University of Kraków, where he stayed for twenty years. ... Zelenchukskaya (Russian: Зеленчукская) is the Caucasus Mountains site of the Special Astrophysical Observatory (Специальная Астрофизическая Обсерватория) of the Russian Academy of Sciences, St Petersburg. ... It has been proposed below that Bulge (astronomy) be renamed and moved to galactic bulge. ... Geoffrey Ronald Burbidge (born September 24, 1925) is a British-American physics professor in the University of California, San Diego. ... Margaret Burbidge (nee Eleanor Margaret Peachey) (born August 12, 1919) is a British astrophysicist, noted for original research and holding many administrative posts, including director of the Royal Greenwich Observatory. ... The Bureau des Longitudes is a French scientific institution, founded by decree of June 25, 1795 and charged with the improvement of nautical navigation, standardisation of time-keeping, geodesy and astronomical observation. ... The Butterfly Cluster (also known as Open Cluster M6, Messier Object 6, Messier 6, M6, or NGC 6405) is an open cluster in the Scorpius constellation. ...

C

C-type asteroids are carbonaceous asteroids. ... Caelum (Latin for chisel, and similar to Latin for of the Sky) is a minor southern constellation introduced by Nicolas Louis de Lacaille. ... In the Mesoamerican calendars, Calendar Round dates are composed by interlacing the dates of the Tzolkin 260 day period (eg the Tzolkin) with that of the 365 day period (known in the Maya language as the Haab). ... Atmosphere none Caliban (kal-i-ban or kal-a-bun) is a moon of Uranus, named after the monster character in William Shakespeares play The Tempest. ... Atmospheric characteristics Atmospheric pressure trace Carbon dioxide 100% Callisto (kÉ™-lis-toe, IPA: ; Greek Καλλιστώ) is a moon of the planet Jupiter, discovered in 1610 by Galileo Galilei. ... The Caltech Submillimeter Observatory (or CSO) is a 10. ... Atmosphere none Calypso (ka-lip-soe, Greek Καλυψώ) is a moon of Saturn. ... The Cambridge Interferometer was a radio telescope interferometer built by Martin Ryle and Antony Hewish in the early 1950s to the west of Cambridge (between the Grange Road football ground and the current Cavendish Laboratory). ... The Cambridge Low-Frequency Synthesis Telescope (CLFST) is an east-west aperture synthesis radio telescope currently operating at 151 MHz. ... COAST, the Cambridge Optical Aperture Synthesis Telescope, is a multi-element optical interferometer with baselines of up to 100 metres, designed to observe stars with angular resolution as high as one thousandth of one arcsecond (much higher resolution than can be obtained with individual telescopes such as the Hubble Space... Camelopardalis, Latin for giraffe, is the name of a large but faint northern constellation first recorded by Jakob Bartsch in 1624, but probably created earlier by Petrus Plancius. ... CFHT image of Eugenia and Petit-Prince CFHT in the morning. ... The Canadian Arrow is a privately funded rocket and space travel project founded by London, Ontario, Canada entrepreneur Geoff Sheerin. ... The Canadian Space Agency (CSA or, in French, lAgence spatiale canadienne, ASC) is the Canadian government department space agency responsible for Canadas space program. ... In astronomy and astrology, Cancer (Latin for crab, symbol , Unicode ♋) is one of the twelve constellations of the zodiac. ... Canes Venatici (Latin for hunting dogs) is a small northern constellation that was introduced by Johannes Hevelius in the 17th century. ... Canis Major (Latin for the greater dog) is one of the 88 modern constellations, and was also in Ptolemys list of 48 constellations. ... The Canis Major Dwarf Galaxy located in the same part of the sky as the constellation of Canis Major. ... Canis Minor (Latin for little dog) is one of the 88 modern constellations, and was also in Ptolemys list of 48 constellations. ... Annie Jump Cannon ( December 11, 1863 – April 13, 1941), US astronomer, was born to shipbuilder and state senator, Wilson Cannon, and his second wife, Mary Jump, in Dover, Delaware. ... Canopus (α Car / α Carinae / Alpha Carinae) is the brightest star in the southern constellation of Carina, and the second brightest star in the sky, with a visual magnitude of −0. ... Canopus (α Car / α Carinae / Alpha Carinae) is the brightest star in the southern constellation of Carina, and the second brightest star in the sky, with a visual magnitude of −0. ... Capella (α Aur / α Aurigae / Alpha Aurigae) is the brightest star in the constellation Auriga and sixth brightest star in the sky. ... Capricornus (♑), a name meaning Horned Goat in Latin, is one of the constellations of the zodiac. ... Capricornus ( or , Unicode: ♑), a name meaning Horned Goat or That which has horns like a goats in Latin, is one of the constellations of the zodiac. ... A carbon star is a red giant (or occasionally red dwarf) star whose atmosphere contains more carbon than oxygen; the two elements combine in the upper layers of the star, forming carbon monoxide and other carbon compounds. ... A compass rose showing the cardinal directions Cardinal directions or cardinal points are the four principal directions or points of the compass in plane. ... Carina (Latin for keel) is a southern constellation which forms part of the old constellation of Argo Navis. ... The Carlsberg Meridian Telescope (formerly the Carlsberg Automatic Meridian Circle) is located at Roque de los Muchachos Observatory and is dedicated to carrying out high-precision optical astrometry. ... Atmospheric pressure 0 kPa Carme (IPA: , kar-mee, Greek Κάρμη) is one of Jupiters moons. ... The Carme group is made up of moons of Jupiter which share similar orbits. ... Carpo (IPA: , kar-poe, Greek Καρπώ) (Jupiter XLVI) is a natural satellite of Jupiter. ... Richard Christopher Carrington (May 26, 1826 – November 27, 1875) was an English astronomer who discovered the differential rotation of the sun by means of sunspot observations in 1863. ... Cartesian means relating to the French mathematician and philosopher Descartes, who, among other things, worked to merge algebra and Euclidean geometry. ... Pierre Cartier (born in Sedan, France in 1932) is a mathematician - more specifically, a category theorist. ... Cartography or mapmaking (in Greek chartis = map and graphein = write) is the study and practice of making maps or globes. ... The Cartwheel Galaxy (also known as ESO 350-40) is a lenticular galaxy about 500 million light-years away in the constellation Sculptor. ... Light path in a Cassegrain reflector First developed in 1672 by Laurent Cassegrain, a Cassegrain Telescope this type of reflector is a combination of a prime concave and a secondary convex mirror, both aligned axially. ... Light path in a Cassegrain reflector Laurent Cassegrain was a catholic priest born in the region of Chartres around 1629 and died at Chaudon (Eure-et-Loir) on August 31, 1693. ... Light path in a Cassegrain Reflector Laurent Cassegrain was a Catholic priest born in the region of Chartres around 1629 and died at Chaudon (Eure-et-Loir) on August 31, 1693. ... This is an artists concept of Cassini during the Saturn Orbit Insertion (SOI) maneuver, just after the main engine has begun firing. ... Giovanni Domenico (Jean-Dominique) Cassini Portrait Giovanni Domenico Cassini (June 8, 1625 - September 14, 1712) was an Italian astronomer and engineer. ... This is an artists concept of Cassini during the Saturn Orbit Insertion (SOI) maneuver, just after the main engine has begun firing. ... This is an artists concept of Cassini during the Saturn Orbit Insertion (SOI) maneuver, just after the main engine has begun firing. ... Cassiopeia is a northern constellation which Greek mythology considered to represent a vain queen. ... Castor (α Gem / α Geminorum / Alpha Geminorum) is the second brightest star in the constellation Gemini and one of the brightest stars in the nighttime sky. ... Castor (α Gem / α Geminorum / Alpha Geminorum) is the second brightest star in the constellation Gemini and one of the brightest stars in the nighttime sky. ... Artists conception of a cataclysmic variable system Cataclysmic variables (also U Geminorum Stars) are a class of binary stars containing a white dwarf and a companion star. ... A catadioptric sensor is a visual sensor that contains mirrors (catoptrics) and lenses (dioptrics). ... The Catalogue of Galaxies and of Clusters of Galaxies (CGCG) was compiled by Fritz Zwicky in 1961–68, and contains 9134 galaxy clusters. ... Bonaventura Cavalieri (1598–1647) was an Italian mathematician whose legacy includes early work on logarithms and geometry, including the rule known today as Cavalieris principle. ... The Cavendish Astrophysics Group (formerly the Radio Astronomy Group) is based at the Cavendish Laboratory at Cambridge University. ... Species About 10-20 species, including: Ceiba aesculifolia Ceiba glaziovii Ceiba insignis Ceiba pentandra Ceiba speciosa Ceiba trichistandra Ceiba is the name of a genus of many species of large trees found in tropical areas, including Central and South America, The Bahamas,the Caribbean, West Africa, and Southeast Asia. ... See lists of astronomical objects for a list of the various lists of astronomical objects in Wikipedia. ... Atmosphere is the general name for a layer of gases that may surround a material body of sufficient mass. ... Atmosphere is the general name for a layer of gases that may surround a material body of sufficient mass. ... In astronomy, a celestial coordinate system is a coordinate system for mapping positions in the sky. ... This article or section should include material from Celestial Mechanics This article or section should be merged with Astrodynamics Celestial mechanics is a term for the application of physics, historically Newtonian mechanics, to astronomical objects such as stars and planets. ... The celestial equator is a great circle on the imaginary celestial sphere, which could be constructed by inflating the Earths equator until it intersects with said sphere. ... Celestial mechanics is a division of astronomy dealing with the motions and gravitational effects of celestial objects. ... Celestial navigation, also known as astronavigation, is a position fixing technique that was the first system devised to help sailors locate themselves on a featureless ocean. ... For other uses of the word pole, see Pole (disambiguation). ... In astronomy and navigation, the celestial sphere is an imaginary rotating sphere of gigantic radius, concentric with the Earth. ... Anders Celsius The observatory of Anders Celsius, from a contemporary engraving. ... Conrad Celtes (1459-1508) was a German Humanist scholar. ... The centaurs are a class of icy planetoids that orbit the Sun between Jupiter and Neptune, named after the mythical race of centaurs. ... Guido Reni, Abduction of Deianira, 1620-21 In Greek mythology, the centaurs (Greek: Κένταυροι) are a race part human and part horse, with a horses body, including all four legs, and a human head and torso with arms. ... The Centaur is an upper stage rocket designed for use on satellite launch vehicles, boosting the satellite into its final orbit or, in the case of interplanetary probes, to escape velocity. ... Centaurus (Latin for centaur) was one of the 48 constellations listed by Ptolemy, and counts also among the 88 modern constellations. ... A Cepheid variable or Cepheid is a member of a particular class of variable stars, notable for a fairly tight correlation between their period of variability and absolute luminosity. ... The Boast of Cassiopeia is a story from Greek mythology, associated with Perseus. ... Cepheus is a northern constellation named after King Cepheus in Greek mythology, and is considered to represent a king. ... Cetus (a name from Greek mythology, referring to a Whale or Sea monster, see Ceto) is a constellation of the southern sky, in the region known as the Water, near other watery constellations like Aquarius, Pisces, and Eridanus. ... The 1. ... Chadwick A. Chad Trujillo (born November 22, 1973) is a postdoctoral scholar at Caltech researching the Kuiper belt and the outer solar system. ... For other uses of the word, see chameleon (disambiguation) Chamaeleon (Latin for chameleon) is a minor southern constellation. ... The Chandler wobble is a small variation in Earths axis of rotation, discovered by American astronomer Seth Carlo Chandler in 1891. ... For other uses, see Chandra (disambiguation). ... Chandra X-ray Observatory is a satellite launched on STS-93 by NASA on July 23, 1999. ... The Chandrasekhar limit, also known as Schenberg-Chandrasekhar limit, is the maximum mass of a white dwarf, a type of star, and is approximately 3 × 1030 kg, around 1. ... This article is about the Indian-American physicist. ... The CHARA Array is an astronomical optical interferometer operated by The Center for High Angular Resolution Astronomy (CHARA) at Georgia State University. ... Charles Thomas Kowal (born November 8, 1940) is an American astronomer. ... Charon (shair-É™n or kair-É™n, IPA , Greek Χάρων), or Pluto I, is the largest satellite of Pluto. ... Emilie du Chatelet Gabrielle Émilie Le Tonnelier de Breteuil, Marquise du Châtelet-Laumont (December 17, 1706 - September 10, 1749) was a French mathematician, physicist and author. ... The Cherenkov Array at Themis (CAT) imager is an atmospheric Cherenkov imaging telescope for detection of high-energy gamma rays (>200 GeV), sited in the French Pyrenees. ... Chinese constellations are different from the western constellations, due to the independent development of ancient Chinese astronomy. ... In Greek mythology, Chiron (hand) — sometimes spelled Cheiron or Kiron — was held as the superlative centaur over his brethren. ... Chondrites are meteorites of the stony type, that have not been modified due to melting or differentiation of the parent body. ... Chondrules in the chondrite Grassland. ... William Henry Mahoney Christie (1845 – January 22, 1922) was a British astronomer. ... Chromatic aberration is caused by the dispersion of the lens material, the variation of its refractive index n with the wavelength of light. ... The chromosphere (literally, color sphere) is a thin layer of the Suns atmosphere just above the photosphere, roughly 10,000 kilometers deep. ... Henri Chrétien (February 1, 1879 – February 6, 1956) was a French astronomer and an inventor. ... Circinus, Latin for Compass, is one of the small southern (declination −50 to −60 degrees) constellations. ... The depth of field is the region where the size of the circle of confusion is less than the resolution of the human eye. ... The 5 main circles of latitude on Earth A circle of latitude or parallel is an imaginary east-west circle on the Earth, that connects all locations with a given latitude. ... Circumpolar stars are those stars which are located near the celestial poles of the celestial sphere, i. ... A protoplanetary disc (also protoplanetary disk, proplyd) is an accretion disc surrounding a T Tauri star. ... Alvan Clark (March 8, 1804 – August 19, 1887), born in Ashfield, Massachusetts, was an American astronomer and telescope maker. ... It has been suggested that this article or section be merged with Newtonian mechanics. ... Classical physics is physics based on principles developed before the rise of quantum theory, including the special theory of relativity. ... Clover is a type of gamma ray detector which has been designed to measure the B-mode polarization of the Cosmic Microwave Background down to a sensitivity limited by the foreground contamination due to lensing, allowing the detection of primordial gravitational waves in the Universe. ... The closure phase is an observable quantity in imaging interferometry, which allowed the use of interferometry with very long baselines. ... The Centre National dÉtudes Spatiales is the French government space agency (administratively, a public establishment of industrial and commercial character). Its headquarters are located in central Paris. ... Knidos or Cnidus (modern-day Tekir in Turkey) is an ancient Greek city in Asia Minor, once part of the country of Caria. ... This article does not cite its references or sources. ... The Coalsack Nebula. ... The Cosmic Background Explorer (COBE), also referred to as Explorer 66, was the first satellite built dedicated to cosmology. ... Cold dark matter (or CDM) is a refinement of the big bang theory that contains the additional assumption that most of the matter in the Universe consists of material which cannot be observed by its electromagnetic radiation and hence is dark while at the same time the particles making up... Shanil Davendra Singh rules 4 life! ... White light is commonly described by its color temperature. ... Columba, Latin for dove, is a small constellation just south to Canis Major and Lepus, it was cut out of the constellation Canis Major by Augustin Royer, in 1679. ... The comet Ikeya-Zhang exhibiting a bright, condensed coma (march 2002) In astronomy, the nebulous envelope around the nucleus of a comet is called its coma (from the Latin word for hair). It is formed when the comet passes close to the sun on its highly elliptical orbit; as the... In optics (especially telescopes), the coma in an optical system refers to monochromatic aberration inherent to certain optical designs or due to imperfection in the lens or other components which results in off-axis point sources such as stars appearing distorted. ... The comet Ikeya-Zhang exhibiting a bright, condensed coma (march 2002) In astronomy, the nebulous envelope around the nucleus of a comet is called its coma (from the Latin word for hair). It is formed when the comet passes close to the sun on its highly elliptical orbit; as the... Coma Berenices (Latin for Berenices Hair) is a traditional asterism that has since become a constellation. ... In optics (especially telescopes), the coma in an optical system refers to monochromatic aberration inherent to certain optical designs or due to imperfection in the lens or other components which results in off-axis point sources such as stars appearing distorted. ... The Coma Cluster is an huge galaxy cluster and the prototypical rich cluster with over a thousand member galaxies known. ... CARMAs logo CARMA at night, credit:David MacMahon The Combined Array for Research in Millimeter-wave Astronomy (CARMA) is a astronomical instrument composed of 23 radio telescopes. ... Comet Hale-Bopp For other uses, see Comet (disambiguation). ... Comet Encke (officially designated 2P/Encke) is a periodic comet, named after Johann Franz Encke, who through laborious study of its orbit and many calculations was able to link multiple observations in 1786 (2P/1786 B1), 1795 (2P/1795 V1), 1805 (2P/1805 U1) and 1818 (2P/1818 W1) to... Comet Halley, officially designated 1P/Halley, more generally known as Halleys Comet after Edmond Halley, is a comet that can be seen every 75-76 years. ... Hubble Space Telescope image of Comet Shoemaker-Levy 9, taken on May 17, 1994. ... Comet Tempel-Tuttle (formally designated as 55P/Tempel-Tuttle) was independently discovered by Ernst Tempel on December 19, 1865 and by Horace Parnell Tuttle on January 6, 1866. ... The comoving distance or conformal distance of two objects in the universe is the distance divided by a time-varying scale factor representing the expansion of the universe. ... In astronomy, a compact star (sometimes called a compact object) is a star that is a white dwarf, a neutron star, a strange star, or a black hole. ... In astronomy, a compact star (sometimes called a compact object) is a star that is a white dwarf, a neutron star, a strange star, or a black hole. ... Compass in a wooden box A compass (or mariners compass) is a navigational instrument for finding directions on the earth. ... Illustration of CGRO The Compton Gamma Ray Observatory(CGRO) was the second of the NASA Great Observatories to be launched to space, following the Hubble Space Telescope. ... In quantum mechanics, the Compton effect, observed by Arthur Compton in 1923, is the increase in wavelength which occurs when X-ray photons with energies of around 0. ... In quantum mechanics, the Compton scattering or Compton effect, observed by Arthur Holly Compton in 1923 that won him the 1927 Nobel Prize in Physics, is the increase in wavelength (decrease in energy) which occurs when X-ray (or gamma ray) photons with energies of around 0. ... In geometry, concavity is a property of certain geometric figures, and in calculus, a property of certain graphs of functions. ... Part of the Cone Emission Nebula is captured in this view from the Hubble Space Telescope. ... Conon of Samos (circa 280 BC - circa: 220 BC) was a Greek mathematician and astronomer. ... Pierce this website is not very reliable!!!!!!!!!!!!!!!!! Some well-known constellations contain striking and familiar patterns of bright stars. ... Constellation-X, the Constellation X-ray Mission (formerly HTXS, the High Throughput X-ray Spectroscopy program) is a Next Generation X-ray Observatory dedicated to observations at high spectral resolution, providing as much as a factor of 100 increase in sensitivity over currently planned high resolution X-ray spectroscopy missions. ... Contact binaries are a type of binary stars where both components of the binary fill their Roche lobes. ... In mathematics, an object is convex if for any pair of points within the object, any point on the straight line segment that joins them is also within the object. ... In astronomy, heliocentrism is the theory that the Sun is at the center of the Universe and/or the Solar System. ... Nicolaus Copernicus (in Latin; Polish Mikołaj Kopernik, German Nikolaus Kopernikus - February 19, 1473 – May 24, 1543) was a Polish astronomer, mathematician and economist who developed a heliocentric (Sun-centered) theory of the solar system in a form detailed enough to make it scientifically useful. ... The Copernican principle is the philosophical statement that no special observers should be proposed. ... The Copernican principle is the philosophical statement that no special observers should be proposed. ... Nicolaus Copernicus (in Latin; Polish Mikołaj Kopernik, German Nikolaus Kopernikus - February 19, 1473 – May 24, 1543) was a Polish astronomer, mathematician and economist who developed a heliocentric (Sun-centered) theory of the solar system in a form detailed enough to make it scientifically useful. ... Nicolaus Copernicus (February 19, 1473 – May 24, 1543) was an astronomer who provided the first modern formulation of a heliocentric (sun-centered) theory of the solar system in his epochal book, De revolutionibus orbium coelestium. ... The Copley Medal is a scientific award for work in any field of science, the highest award granted by the Royal Society of London. ... Atmospheric pressure 0 kPa Cordelia (kor-dee-lee-a) is the innermost moon of Uranus. ... Cornelius Agrippa, as portrayed in Libri tres de occulta philosophia Heinrich Cornelius Agrippa von Nettesheim (born in Köln September 14, 1486 - died in Grenoble February 18, 1535) was a magician and occult writer, astrologer, and alchemist. ... The corona is the luminous plasma atmosphere of the Sun extending millions of kilometres into space, most easily seen during a total solar eclipse, but also observable in a coronagraph. ... Corona Australis or Corona Austrina (Latin for Southern Crown) was one of Ptolemys 48 constellations, and also counts among the 88 modern constellations. ... Corona Borealis (Latin for northern crown) is a small northern constellation whose main stars form a semicircular arc. ... An example image from SOHO - NASA A coronagraph is a telescopic attachment designed specifically to block out the harsh, direct light from a star, so that nearby objects can be resolved without burning out the telescopes optics. ... Corot is a space mission of the French Space Agency (CNES) and the European Space Agency, with a launch planned in 2006. ... Corvus (Latin for Raven/Crow) is a small southern constellation with only 11 stars visible to the naked eye (brighter than magnitude 5. ... The Cosmic Anisotropy Telescope CAT was a three-element interferometer for cosmic microwave background observations at 13 to 17 GHz, based at the Mullard Radio Astronomy Observatory. ... The Cosmic Background Explorer (COBE), also referred to as Explorer 66, was the first satellite built dedicated to cosmology. ... The Cosmic Background Imager (or CBI) is a 13-element interferometer perched at an elevation of 5000 metres on the Chajnantor plateau in the Chilean Andes. ... When any patch of the sky is observed where no individual sources can be discerned, and the effects of interplanetary dust, and interstellar matter are taken into account, there is still radiation. ... When any patch of the sky is observed where no individual sources can be discerned, and the effects of interplanetary dust, and interstellar matter are taken into account, there is still radiation. ... This article is in need of attention from an expert on the subject. ... Cosmic inflation is the idea, first proposed by Alan Guth in 1981, that the nascent universe passed through a phase of exponential expansion (the inflationary epoch) that was driven by a negative pressure vacuum energy density. ... WMAP image of the CMB anisotropy,Cosmic microwave background radiation(June 2003) The cosmic microwave background radiation (CMB) is a form of electromagnetic radiation that fills the whole of the universe. ... In cosmology, the cosmic microwave background radiation (most often abbreviated CMB but occasionally CMBR, CBR or MBR) is a form of electromagnetic radiation discovered in 1965. ... Cosmic rays can loosely be defined as energetic particles originating outside of the Earth. ... Cosmic rays can loosely be defined as energetic particles originating outside of the Earth. ... Cosmic ray spallation is a form of naturally occuring nuclear fission and nucleosynthesis. ... Cosmic rays can loosely be defined as energetic particles originating outside of the Earth. ... To meet Wikipedias quality standards, this article or section may require cleanup. ... The Cosmological Principle is a principle invoked in cosmology that severely restricts the large variety of possible cosmological theories: On large scales, the Universe is homogeneous and isotropic. ... The cosmological constant (usually denoted by the Greek capital letter lambda: Λ) occurs in Einsteins theory of general relativity. ... The Cosmological Principle is a principle invoked in cosmology that severely restricts the large variety of possible cosmological theories: On large scales, the Universe is homogeneous and isotropic. ... A graphical timeline is available here: Graphical timeline of the Big Bang This timeline of the Big Bang describes the events that have occurred and will occur according to the scientific theory of the Big Bang. ... Cosmology, from the Greek: κοσμολογία (cosmologia, κόσμος (cosmos) world + λογια (logia) discourse) is the study of the universe in its totality and by extension mans place in it. ... U.S. Space Shuttle astronaut Bruce McCandless II using a manned maneuvering unit (MMU) outside the Challenger in 1984. ... The Côte dAzur Observatory (in French: Observatoire de la Côte dAzur) originated in 1988 with the merger of two observatories: Nice Observatory The CERGA (Centre dÉtudes et de Recherches Géodynamiques et Astronomiques) External links Côte dAzur Observatory official website (English version) ... Messier Object 1, the Crab Nebula. ... Tycho crater on Earths moon. ... Crater (Latin for cup) is one of the 88 modern constellations and was also one of the 48 listed by Ptolemy. ... ... Atmospheric pressure 0 kPa Cressida (kres-i-da) is a moon of Uranus. ... The CRESU experiment (meaning Cinétique de Réaction en Ecoulement Supersonique Uniforme, or Reaction Kinetics in Uniform Supersonic Flow) is an experiment investigating chemical reactions taking place at very low temperatures. ... Mare Crisium Studios is also the name of a company formed to develop the game Stars! Supernova Genesis. ... The Cryogenic Dark Matter Search (CDMS) is an experiment designed to directly detect particle dark matter in the form of WIMPs. ... A cubewano is any substantial Kuiper belt object, orbiting beyond about 41 AU and not controlled by resonances with the outer planets. ... Cygnus (Latin for swan) is a northern constellation. ... For the software company, see Cygnus Solutions. ... Cygnus, the constellation in which Deneb is located. ... Location of the X-ray source Cygnus X-1, which is widely accepted to be a 10 solar mass black hole orbiting a blue giant star. ...

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Jean le Rond dAlembert, pastel by Maurice Quentin de la Tour Jean le Rond dAlembert (November 16, 1717 – October 29, 1783) was a French mathematician, mechanician, physicist and philosopher. ... D-type asteroids have a very low albedo and a featureless reddish spectrum. ... 243 Ida (left) and Dacytl (right), as photographed by Galileo. ... Damocloids are asteroids such as 5335 Damocles and (16746) 1996 PW that have long-period highly eccentric orbits typical of periodic comets such as 1P/Halley, but without showing a cometary coma or tail. ... The Danjon Scale of lunar eclipse brightness is a five-point scale useful for measuring the appearance and luminosity of the Moon during a lunar eclipse. ... André-Louis Danjon (April 6, 1890 – April 21, 1967) was a French astronomer born in Caen, France. ... Image of Daphnis obtained by Cassini showing the ripples it induces in the edges of the Keeler gap. ... In cosmology, dark energy is a hypothetical form of energy which permeates all of space and has strong negative pressure. ... In cosmology, dark matter refers to hypothetical matter particles, of unknown composition, that do not emit or reflect enough electromagnetic radiation to be detected directly, but whose presence can be inferred from gravitational effects on visible matter such as stars and galaxies. ... The dark moon is the time when the Moon is so close to the Sun in the sky that it cannot be seen even near sunset or sunrise. ... Arguably the most famous dark nebula, the Horsehead Nebula. ... Darwin is a proposed European Space Agency (ESA) mission designed to directly detect Earth-like planets orbiting nearby stars, and search for evidence of life on these planets. ... There is more than one crater named Darwin: Darwin (Lunar crater) Darwin (crater on Mars) This is a disambiguation page — a navigational aid which lists other pages that might otherwise share the same title. ... Dawn or civil dawn is the time at which the Sun is 6 degrees below the horizon in the morning. ... Abbé Nicolas Louis de Lacaille (March 15, 1713 – March 21, 1762) was a French astronomer. ... Title page of De revolutionibus De revolutionibus orbium coelestium (English: On the Revolutions of the Heavenly Spheres, Polish: O obrotach sfer niebieskich) is the seminal work on heliocentric theory and the masterpiece of the great Polish astronomer Nicolaus Copernicus. ... Gérard Henri de Vaucouleurs (April 25, 1918–October 7, 1995) was a French-American astronomer. ... In plasma physics, the Debye length, named after the Dutch physical chemist Peter Debye, is the scale over which mobile charge carriers (e. ... In astronomy, declination (dec) is one of the two coordinates of the equatorial coordinate system, the other being either right ascension or hour angle. ... Deep sky object (DSO) is a term used often in amateur astronomy to denote objects in the night sky other than solar system objects (such as planets, comets and asteroids), single stars and multiple star systems. ... In the Ptolemaic system of astronomy, the epicycle (literally: on the cycle in Greek) was a geometric model to explain the variations in speed and direction of the apparent motion of the Moon, Sun, and planets. ... Degenerate matter is matter which has sufficiently high density that the dominant contribution to its pressure arises from the Pauli exclusion principle. ... A degree (in full, a degree of arc, arc degree, or arcdegree), usually symbolized °, is a measurement of plane angle, representing 1／360 of a full rotation. ... Deimos (IPA or ; Greek Δείμος: Dread), is the smaller and outermost of Mars two moons, named after Deimos from Greek Mythology. ... Deimos (IPA or ; Greek Δείμος: Dread), is the smaller and outermost of Mars two moons, named after Deimos from Greek Mythology. ... Delphinus, being Latin for Dolphin, is a rather small (ranked 69th) northern constellation very close to the celestial equator. ... Delphinus, being Latin for Dolphin, is a rather small (ranked 69th) northern constellation very close to the celestial equator. ... Cygnus, the constellation in which Deneb is located. ... Denebola, or Beta Leonis, is the second-brightest star in the constellation of Leo. ... Atmospheric pressure 0 kPa Desdemona (dez-di-moe-na) is a moon of Uranus. ... A simulated view of Despina orbiting Neptune Despina (des-pee-na or des-pye-na; Latin DespÅ“na from Greek Δεσποίνη) is the third known moon of Neptune. ... Detached binaries are a kind of binary stars where each component is within its Roche lobe. ... Diffraction is the bending and spreading of waves when they meet an obstruction. ... The ability to produce optical images with angular separations as small as the instruments theoretical limit. ... This article needs to be cleaned up to conform to a higher standard of quality. ... Herbert Dingle (1890 – 1978) was an English astrophysicist. ... Atmosphere none Dione (dye-oe-nee, Greek Διώνη) is a moon of Saturn discovered by Giovanni Cassini in 1684. ... Paul Adrien Maurice Dirac Paul Adrien Maurice Dirac, OM (IPA: [dɪræk]) (August 8, 1902 – October 20, 1984) was a British theoretical physicist and a founder of the field of quantum physics. ... The most common form of galxy is the butt plug of doom A disc is a component of disc galaxies, such as spiral galaxies, or lenticular galaxies. ... Dispersion of a light beam in a prism. ... Diurnal motion is an astronomical term referring to the apparent daily motion of stars in orbit around the Earth, caused by the Earths rotation around its axis. ... Dmitri Dmitrievich Maksutov (Russian:Дмитрий Дмитриевич Максутов) (April 23 (April 11 (O.S.)) 1896-August 12, 1964) was a Soviet/Russian optician. ... In astronomy the Dobsonian is a type of alt-azimuth telescope mounting that became popular among amateur astronomers in the 1980s because of its extreme simplicity, low price, and rugged construction. ... In astronomy the Dobsonian is a type of telescope mounting that became popular in the 1980s for its extreme simplicity, low price, and rugged construction. ... Audouin Charles Dollfus (November 12, 1924 – ) is a French astronomer. ... Dome C, also known as Dome Circe or Dome Charlie, ( 75° S 123° E) is a local feature of the Antarctic Plateau, and site of the Concordia scientific station. ... The Doppler effect, named after Christian Andreas Doppler, is the apparent change in frequency or wavelength of a wave that is perceived by an observer moving relative to the source of the waves. ... The Doppler effect is the apparent change in frequency or wavelength of a wave that is perceived by an observer moving relative to the source of the waves. ... Other uses: dorado is used in the fisheries of some Latin American countries to denote the edible fish mahi-mahi (Coryphaena hippurus Dorado is also the name of mythical Latin American warriors. ... A double pendulum is a pendulum with another pendulum attached to its end, and is a simple physical system that exhibits rich dynamic behavior. ... Double Star is a science fiction novel by Robert A. Heinlein. ... Look up Draconian in Wiktionary, the free dictionary. ... Draco (Latin for Dragon) is a far northern constellation that is circumpolar for many northern hemisphere observers. ... The Drake equation (also known as the Green Bank equation or the Sagan equation) is a famous result in the speculative fields of xenobiology, astrosociobiology and the search for extraterrestrial intelligence. ... Professor Frank Drake Frank Drake (born May 28, 1930, Chicago, Illinois) is an American astronomer and astrophysicist. ... Henry Draper (March 7, 1837 – November 20, 1882) was an American doctor and astronomer. ... John Louis Emil Dreyer (February 13, 1852 – September 14, 1926) was a Danish-Irish astronomer. ... The drift velocity is the average velocity that a particle, such as an electron, attains, due to an electric field. ... Dubhe (α Ursae Majoris) is the second-brightest star in the constellation of Ursa Major. ... Messier Object 27, the Dumbbell Nebula The Dumbbell Nebula (also known as Messier Object 27, M27, or NGC 6853) is a planetary nebula in the Vulpecula constellation, at a distance of about 1250 light years. ... Robert Duncan is an astrophysicist at the University of Texas at Austin. ... Dusk in Breaux Bridge, Louisiana, USA. Dusk or civil dusk is the time at which the sun is 6 degrees below the horizon in the evening. ... After just three years of use dust has blocked this laptop heat sink, making the computer unusable Dust is a general name for minute solid particles with diameter less than 500 micrometers (otherwise see sand or granulates) and, more generally, for finely divided matter. ... Innovative new optical solar telescope at the Roque de los Muchachos Observatory on La Palma (near the Swedish Solar Telescope). ... Dwarf elliptical are very small elliptical galaxies, classified as dE. They are quite common, and usually are companions to other galaxies. ... A dwarf galaxy is a small galaxy composed of up to several billion stars, a small number compared to our own Milky Ways 200-400 billion stars. ... Dwarf spheroidal galaxy (dSph) is a term in astronomy applied to the nine low luminosity dwarf elliptical galaxies that are companions to the Milky Way and to the similar systems that are companions to the Andromeda Galaxy M31. ... A dynamical system is a concept in mathematics where a fixed rule describes the time dependence of a point in a geometrical space. ... In engineering and mathematics, a dynamical system is a deterministic process in which a functions value changes over time according to a rule that is defined in terms of the functions current value. ... Sir Frank Watson Dyson (January 8, 1868 – May 25, 1939) was an English astronomer. ... Freeman Dyson in San Francisco in 2005 (Photo: Jacob Appelbaum) Freeman John Dyson (born December 15, 1923) is an English-born American physicist and mathematician, famous for his work in quantum mechanics, nuclear weapons design and policy, and for his serious theorizing in futurism and science fiction concepts, including the...

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E-type asteroids are inner-belt asteroids that contain enstatite. ... Earth is the third planet in the Sol system. ... Earths atmosphere is the layer of gases surrounding the planet Earth and retained by the Earths gravity. ... Artists impression of a major impact event. ... Layers of Atmosphere (NOAA) Earths atmosphere is a layer of gases surrounding the planet Earth and retained by the Earths gravity. ... This article or section does not cite its references or sources. ... Leonardo da Vincis sketch of crescent Moon with earthshine as part of his Codex Leicester, written between 1506 and 1510. ... The eccentric anomaly is the angle between the direction of periapsis and the current position of an object on its orbit, projected onto the ellipses circumscribing circle perpendicularly to the major axis, measured at the centre of the ellipse. ... In astrodynamics, under standard assumptions any orbit must be of conic section shape. ... In astrodynamics, under standard assumptions any orbit must be of conic section shape. ... ECLiPSe is a constraint logic programming language developed in IC-Parc. ... Animation showing how an eclipsing binary stars light intensity changes as they orbit An eclipsing binary star is a binary star in which the orbit plane of the two stars lies so nearly in the line of sight of the observer that the components undergo mutual eclipses. ... The plane of the ecliptic is well seen in this picture from the 1994 lunar prospecting Clementine spacecraft. ... The ecliptic coordinate system is a celestial coordinate system that uses the ecliptic for its fundamental plane. ... Ecliptic longitude is one of the co-ordinates which can be used to define the location of an astronomical object on the celestial sphere in ecliptic coordinates. ... The Eddington Medal, named after Sir Arthur Eddington, is awarded by the Royal Astronomical Society nominally once every two years for investigations of outstanding merit in theoretical astrophysics. ... In physics, the Eddington Limit is a natural limit to the luminosity that can be radiated by spherically symmetric accretion onto a compact object, like a black hole. ... Eddington luminosity (sometimes also called the Eddington limit) is the largest luminosity that can pass through a layer of gas in hydrostatic equilibrium, supposing spherical symmetry. ... One of Sir Arthur Stanley Eddingtons papers announced Einsteins theory of general relativity to the English-speaking world. ... Edmond Halley. ... Edward Charles Pickering (July 19, 1846 – February 3, 1919) was an American astronomer and physicist, brother of William Henry Pickering. ... Since its inauguration in 1972, the Effelsberg 100-m radio telescope is one of the worlds largest fully steerable telescopes. ... To meet Wikipedias quality standards, this article may require cleanup. ... Einstein Observatory (HEAO-2) was the first fully imaging X-ray telescope put into space and the second of NASAs three High Energy Astrophysical Observatories. ... For other topics related to Einstein see Einstein (disambig) In the general theory of relativity by Albert Einstein, the gravitational redshift or Einstein shift is the effect that clocks in a gravitational field tick slower when observed by a distant observer. ... Atmospheric pressure 0 kPa Elara (ee-lur-a or ee-lair-a, IPA or , Greek Ελάρη) is a moon of Jupiter. ... Eleanor Francis Helin is an American astronomer, principal investigator of the Near Earth Asteroid Tracking (NEAT) program of NASAs Jet Propulsion Laboratory. ... Electromagnetic radiation can be conceptualized as a self propagating transverse oscillating wave of electric and magnetic fields. ... Legend: γ = Gamma rays HX = Hard X-rays SX = Soft X-Rays EUV = Extreme ultraviolet NUV = Near ultraviolet Visible light NIR = Near infrared MIR = Moderate infrared FIR = Far infrared Radio waves: EHF = Extremely high frequency (Microwaves) SHF = Super high frequency (Microwaves) UHF = Ultrahigh frequency VHF = Very high frequency HF = High frequency... Two bodies with similar mass orbiting around a common barycenter with elliptic orbits. ... The jet emitted by M87 in this image is thought to be caused by a supermassive black hole at the galaxys center. ... An elliptical galaxy is a type of galaxy in the Hubble sequence characterized by the following physical properties: The giant elliptical galaxy NGC 4881 (the spherical glow at upper left) lies at the edge of the Coma Cluster of Galaxies. ... In astrodynamics or celestial mechanics a elliptic orbit is an orbit with the eccentricity greater than 0 and less than 1. ... Elnath (or El Nath), is a star in the constellation Taurus. ... This diagram shows the elongations (or angle) of the Earths position from the Sun. ... For alternate meanings, see Lightning (disambiguation). ... A spectral line is a dark or bright line in an otherwise uniform and continuous spectrum, resulting from an excess or deficiency of photons in a narrow frequency range, compared with the nearby frequencies. ... An emission nebula is a cloud of ionized gas ( a plasma) emitting light of various colors. ... [5] Atmospheric characteristics Pressure trace, significant spatial variability [6] Water vapour 65% [7] Hydrogen 20% [8] Other CO2, CO, N2 [9] Enceladus (en-sel-É™-dÉ™s, IPA , Greek Εγκέλαδος) is the sixth-largest moon of Saturn, discovered in 1789 by William Herschel [10]. Despite its small size, Enceladus has a wide... The Encke Division in closeup The Encke Division, also called the Encke Gap, is a perceived gap within Saturns A Ring. ... Johann Franz Encke (September 23, 1791 – August 26, 1865) was a German astronomer, born in Hamburg. ... Energy density is the amount of potential energy stored in a given system or region of space per unit volume. ... An ephemeris (plural: ephemerides) (from the Greek word ephemeros= daily) was, traditionally, a table providing the positions (given in a Cartesian coordinate system, or in right ascension and declination or, for astrologers, in longitude along the zodiacal ecliptic), of the Sun, the Moon, the planets, asteroids or comets in the... Ephemeris Time (ET) is the time scale used in ephemerides of celestial bodies, in particular the Sun (as observed from the Earth), Moon, planets, and other members of the solar system. ... Epimetheus (ep-i-mee-thee-us, Greek Επιμηθεύς) is a moon of Saturn. ... In astronomy, an epoch is a moment in time for which celestial coordinates or orbital elements are specified. ... An eponym is a person, whether real or fictitious, whose name has (or is thought to have) given rise to the name of a particular place, tribe, discovery, or other item. ... In quantum mechanics, the EPR paradox (Einstein-Podolsky-Rosen) is a thought experiment that demonstrates that the result of a measurement performed on one part of a quantum system can have an instantaneous effect on the result of a measurement performed on another part, regardless of the distance separating the... Epsilon Eridani (ε Eri / ε Eridani) is a main-sequence K2 class star in the constellation of Eridanus. ... Epsilon Indi (ε Ind / ε Indi) is a star approximately 11. ... During the course of the year, the time as read from a sundial can run ahead of clock time by as much as 16 min 33 s (around October 31–November 1) or fall behind by as much as 14 min 6 s (around February 11–12). ... An equatorial bulge is a planetological term which describes a bulge which a planet may have around its equator, distorting it into an oblate spheroid. ... The equatorial coordinate system is probably the most widely used celestial coordinate system, whose equatorial coordinates are: declination () right ascension () or hour angle () It is the most closely related to the geographic coordinate system, because they use the same fundamental plane, and the same poles. ... An Equatorial Mount for a telescope. ... An equinox in astronomy is the moment when the Sun passes over the equator. ... Equuleus (Latin for horse-let (i. ... Eratosthenes (Ερατοσθένης) Eratosthenes (Ερατοσθένης) (276 BC - 194 BC) was a Hellenistic mathematician, geographer and astronomer. ... The Eratosthenian period in the lunar geologic timescale runs from 3,200 million years ago to 1,100 million years ago. ... Eridanus is the sixth largest of the 88 modern constellations. ... Ernest Rutherford Ernest Rutherford, 1st Baron Rutherford of Nelson, OM, PC, FRS (August 30, 1871 – October 19, 1937), was a New Zealand nuclear physicist. ... Ernst Wilhelm Leberecht Tempel (December 4, 1821 – March 16, 1889) was a German astronomer who worked in Marseille until the outbreak of the Franco-Prussian War in 1870, then later moved to Italy. ... Erriapo (air-ee-ap-oe?, Latin Erriapō or Erriappō) (Saturn XXVIII) is a natural satellite of Saturn. ... An eruptive variable is a variable star characterised by sudden extreme increases in luminosity. ... This article is about the European Space Agency. ... The ESA Space Debris Telescope is located on the island of Tenerife, Spain. ... In physics, for a given gravitational field and a given position, the escape velocity is the minimum speed an object without propulsion, at that position, needs to have to move away indefinitely from the source of the field, as opposed to falling back or staying in an orbit within a... Hubble Space Telescope image showing Eta Carinae and the bipolar Homunculus Nebula which surrounds the star. ... R-phrases S-phrases , , , Flash point -135 °C Autoignition temperature 472 °C Explosive limits 3. ... Euclid Euclid of Alexandria (Greek: ) (ca. ... Euclid Euclidean geometry is a mathematical system due to the Hellenistic mathematician Euclid of Egypt. ... In mathematics, Euclidean space is a generalization of the 2- and 3-dimensional spaces studied by Euclid. ... For the crater, see Euctemon (crater). ... Eudoxus of Cnidus (Greek Εύδοξος) (410 or 408 BC - 355 or 347 BC) was a Greek astronomer, mathematician, physician, scholar and friend of Plato. ... species numerous; see text Eugenia is a genus of flowering plants, belonging to the myrtle family (Myrtaceae). ... Euler angles are the classical way of representing rotations in 3-dimensional Euclidean space, named after Leonhard Euler. ... Leonhard was the first to use the term function to describe an expression involving various arguments; i. ... Atmospheric characteristics Atmospheric pressure 1 µPa Oxygen 100% Europa (ew-roe-pÉ™, IPA: (help· info); Greek Ευρώπη) is a moon of the planet Jupiter. ... The European Southern Observatory (ESO) is an international astronomical organisation, composed and supported by ten countries from the European Union plus Switzerland and was created in 1962. ... The European Space Agency (ESA), established in 1975, is an inter-governmental organisation dedicated to the exploration of space, currently with 17 member states. ... The European VLBI Network (EVN) was formed in 1980 by a consortium of five of the major radio astronomy institutes in Europe (the European Consortium for VLBI). ... Event Horizon is a 1997 science fiction and horror film. ... The many-worlds interpretation (or MWI) is an interpretation of quantum mechanics, based on Hugh Everetts relative-state formulation. ... Hugh Everett III (November 11, 1930 – July 19, 1982) was an American physicist who first proposed the many-worlds interpretation of quantum physics, which he called his relative state formulation. ... For Solar Eclipse, the alien friend of the rubber doll Betty Spaghetty, see Betty Spaghetty Photo taken by John Walker during the Zambia 2001 eclipse A solar eclipse occurs when the Sun, Moon and Earth are on a single line with the Moon in the middle. ... The exit pupil is a concept in optics, and is defined as the minimum diameter of the light beam leaving an eyepiece though which all of the light from the eyepiece passes. ... Infrared Image of a possible extrasolar planet (lower left) in the Constellation Taurus, taken by the Hubble Space Telescope. ... The Exosat satellite was operational from May 1983 until April 1986 and in that time made 1780 observations in the X-ray band of most classes of astronomical object including active galactic nuclei, stellar coronae, cataclysmic variables, white dwarfs, X-ray binaries, clusters of galaxies, and supernova remnants. ... Extragalactic astronomy is the branch of astronomy concerned with objects outside our own Milky Way Galaxy (the study of all astronomical objects which are not covered by galactic astronomy). ... Infrared image of the star GQ Lupi (A) orbited by a planet (b) at a distance of approximately 20 times the distance between Jupiter and our Sun. ... Extraterrestrial life is life that may exist and originate outside the planet Earth. ... The Extreme Universe Space Observatory - EUSO is the first Space mission devoted to the investigation of cosmic rays and neutrinos of extreme energy (E > 5 x 10e19 eV), using the Earths atmosphere as a giant detector, the detection being performed by looking at the streak of fluorescence light produced... An eyepiece, or ocular lens, is a type of lens that is attached to a variety of optical devices such as telescopes and microscopes. ...

F

A 35mm lens set to f/11, as indicated by the white dot above the f-stop scale on the aperture ring In photography the f-number (focal ratio) expresses the diameter of the diaphragm aperture in terms of the effective focal length of the lens. ... F-type asteroid is a subdivision of C-type asteroids distinguished spectrally by differences in the ultraviolet absorption and the lack of a water absorption feature at 3 micrometres. ... David and Johannes Fabricius were father and son astronomers from Frisia. ... David and Johannes Fabricius were father and son astronomers from Frisia. ... A facula (plural: faculae) is literally a bright spot. ... Far infrared astronomy is the branch of astronomy and astrophysics which deals with objects visible in far-infrared radiation (approximatively from 30μm to 300μm). ... Far side of the Moon. ... Galaxy Abell 1835 IR1916 is seen as a tiny dot in this photo of distant galaxies. ... The Faulkes Telescope North is a clone of the Liverpool Telescope, and is located at Haleakala Observatory. ... The Faulkes Telescope South is a clone of the Liverpool Telescope, and is located at Siding Spring Observatory. ... A graphical representation of the Arecibo message, Humanitys first attempt to communicate its existence to alien civilizations The Fermi Paradox is a physical paradox that was brought to light by a simple question posed by the physicist Enrico Fermi when speculating about the existence of technologically advanced civilizations within... Enrico Fermi in the 1940s Enrico Fermi (September 29, 1901 – November 28, 1954) was an Italian physicist most noted for his work on beta decay, the development of the first nuclear reactor, and for the development of quantum theory. ... Richard Phillips Feynman (May 11, 1918 – February 15, 1988) (surname pronounced FINE-man; in IPA) was one of the most influential American physicists of the 20th century, expanding greatly the theory of quantum electrodynamics, quark theory, and the physics of the superfluidity of supercooled liquid helium. ... In physics, a field is an assignment of a quantity to every point in space (or more generally, spacetime). ... The field of view is the part of the observable world that is seen at any given moment. ... A Finderscope is a small auxilliary telescope mounted atop the main astronomical telescope and pointed in the same direction. ... The First Point of Aries, also called the vernal equinox point, is one of the two points on the celestial sphere where the celestial equator intersects the ecliptic. ... The First Point of Libra, also called the autumnal equinox point, is one of the two points on the celestial sphere where the celestial equator intersects the ecliptic. ... The first light is the moment when a telescope is first used to take an astronomical image after its construction. ... FITS or Flexible Image Transfer System is the most commonly used file format in astronomy. ... The Lorentz-Fitzgerald contraction hypothesis was proposed by Fitzgerald and independently proposed and extended by Lorentz to explain the negative result of the Michelson-Morley experiment, which attempted to detect Earths motion relative to the luminiferous aether. ... FRCAO Radome-enclosed 14-m Telescope. ... Flamsteed designations for stars are similar to Bayer designations, except that they use numbers instead of Greek letters. ... John Flamsteed - Wikipedia, the free encyclopedia /**/ @import /skins-1. ... A flare star is a variable star which can undergo unpredictable dramatic increases in brightness for a few minutes or a few hours. ... The notion of a Flat Earth refers to the idea that the inhabited surface of the Earth is flat, rather than curved (see Spherical Earth). ... The flatness problem is a cosmological problem with the Big Bang theory, which is solved by hypothesising an inflationary universe. ... In the various subfields of physics, there exist two common usages of the term flux, both with rigorous mathematical frameworks. ... The focal point F and focal length f of a positive lens, a negative lens, a concave mirror, and a convex mirror. ... The focal plane of a lens is a plane that is perpendicular to the axis of the lens and passes through its focus. ... Look up focus in Wiktionary, the free dictionary. ... Fomalhaut (α PsA / α Piscis Austrini / Alpha Piscis Austrini) is the brightest star in the constellation Piscis Austrinus and one of the brightest stars in the nighttime sky. ... A forbidden line is a spectral line emitted by atoms undergoing energy transitions not normally allowed by the selection rules of quantum mechanics. ... Fornax (Latin for furnace) is a southern constellation which was first introduced by Nicolas Louis de Lacaille under the name Fornax Chemica (Latin for chemical furnace). ... In relativity, a four-vector is a vector in a four-dimensional real vector space, whose components transform like the space and time coordinates (ct, x, y, z) under spatial rotations and boosts (a change by a constant velocity to another inertial reference frame). ... There is another William Fowler who was a Scottish poet and uncle of William Drummond of Hawthornden William Alfred Willy Fowler (August 9, 1911 – March 14, 1995) was an American astrophysicist. ... Frame of reference - Wikipedia, the free encyclopedia /**/ @import /skins-1. ... François Arago François Jean Dominique Arago (February 26, 1786 – October 2, 1853) was a French mathematician, physicist, astronomer, and politician. ... François Jean Dominique Arago (February 26, 1786 – October 2, 1853) was a French mathematician, physicist, astronomer, and politician. ... Frederick de Houtman (1571—1627) was a Dutch explorer who sailed along the Western coast of Australia (see History of Western Australia) en route to Batavia. ... The Friedmann equations relate various cosmological parameters within the context of general relativity. ... The Friedmann-Lemaître-Robertson-Walker (FLRW) metric describes a homogeneous, isotropic expanding/contracting universe. ... Friedrich Karl Arnold Schwassmann (March 25, 1870 – January 19, 1964) was a German astronomer). ... Friedrich Wilhelm Bessel (July 22, 1784 – March 17, 1846) was a German mathematician, astronomer, and systematizer of the Bessel functions (which, despite their name, were discovered by Daniel Bernoulli). ... The Galileo spacecraft took this composite image on 7 December 1992 on its way to explore the Jupiter system in 1995-97. ... The full moon cycle (the abbreviation fumocy was introduced by Karl Palmen in the CALNDR-L mailing list in October 2002) is a cycle of about 14 lunations over which full moons vary in apparent size. ... Full-sky Astrometric Mapping Explorer (FAME) was a proposed space telescope, planned for launch in 2004, designed to obtain highly precise position and brightness measurements of 40 million stars. ... The fundamental plane in a spherical coordinate system is a plane which divides the sphere into two hemispheres. ... Zeta Canis Majoris (or Furud/Phurud; abbr. ...

G

Gérard Henri de Vaucouleurs (April 25, 1918–October 7, 1995) was a French-American astronomer. ... G-type asteroid is a subdivision of C-type asteroids distinguished spectrally by differences in the ultraviolet absorption. ... Gacrux (γ Cru / γ Crucis / Gamma Crucis) is the third brightest star in constellation Crux (the Southern Cross) and the one of the brightest stars in the nighttime sky. ... The Gaia satellite is an astrometry space mission, and a successor to the ESA Hipparcos mission. ... Galactic astronomy is the study of galaxies, their formation, structure, components, dynamics, interactions, and the range of forms they take. ... In astronomy, a bulge is a huge, tightly packed group of stars. ... An open cluster is a group of stars (star cluster) that were born at the same time from a molecular cloud, and are still near to each other. ... Many galaxies, including the Milky Way in which our Sun and Earth are located, are disk-shaped: the majority of their visible mass (excluding possible dark matter) lies very close to a plane. ... The Structure of the Galaxy The galactic corona (not to be confused with the suns corona), also called the dark matter halo, is a region of space surrounding the galactic halo of spiral galaxies, including the Milky Way Galaxy that consist mostly of dark matter. ... Galactic cosmic rays (GCRs) are the high-energy particles that flow into our solar system from far away in the Galaxy. ... It has been proposed below that Disc (galaxy) be renamed and moved to galactic disc. ... The galactic halo is a region of space surrounding spiral galaxies, including our galaxy, the Milky Way. ... The galactic plane is the plane in which the majority of a flattened galaxys mass lies. ... A simulated view of Galatea orbiting Neptune Galatea (gal-a-tee-a, Greek Γαλατεία) is the fourth known moon of Neptune, named after Galatea, one of the Nereids of Greek legend. ... This article is about a celestial body. ... NGC 4414, a typical spiral galaxy in the constellation Coma Berenices, is about 56,000 light years in diameter and approximately 60 million light years distant. ... Galaxy Abell 1835 IR1916 is seen as a tiny dot in this photo of distant galaxies. ... Astronomers classify galaxies based on their overall shape (elliptical, spiral or barred spiral) and further by the specific properties of the individual galaxy (for example degree of ellipse, number of spirals or definition of bar). ... Galaxy groups and clusters are super-structures in the spread of galaxies of the cosmos. ... A disc is a component of disc galaxies, such as spiral galaxies, or lenticular galaxies. ... REDIRECT [[ --68. ... The galaxy rotation problem is the discrepancy between the observed rotation speeds of matter in the disk portions of spiral galaxies and the predictions of Newtonian dynamics considering the luminous mass. ... The Galaxy Evolution Explorer is an orbiting space telescope that was launched on April 28, 2003. ... Jupiters 4 Galilean moons, in a composite image comparing their sizes and the size of Jupiter (Great Red Spot visible). ... The Galilean transformation is used to transform between the coordinates of two coordinate systems in a constant relative motion in Newtonian physics. ... Galileo Galilei. ... Galileo being deployed after being launched by the Space Shuttle Atlantis on the STS-34 mission Galileo was an unmanned spacecraft sent by NASA to study the planet Jupiter and its moons. ... Galileo is prepared for mating with the IUS booster Galileo being deployed after being launched by the Space Shuttle Atlantis on the STS-34 mission Galileo was an unmanned spacecraft sent by NASA to study the planet Jupiter and its moons. ... Johann Gottfried Galle (June 9, 1812 – July 10, 1910) was a German astronomer at the Berlin Observatory who, with help from Urbain Le Verrier, sighted Neptune on September 23, 1846. ... Optical afterglow of gamma ray burst GRB-990123 (the bright dot within the white square and in the enlarged cutout) on 23 January 1999. ... In astronomy, gamma-ray bursts (GRBs) are flashes of gamma rays that last from seconds to hours, the longer ones being followed by several days of X-ray afterglow. ... The Gamma-ray Large Area Space Telescope, or GLAST, is a future space-based gamma-ray telescope, designed to explore the high-energy Universe. ... Gamma-ray astronomy is the astronomical study of the cosmos with gamma rays. ... George Gamow (pronounced GAM-off) (March 4, 1904 – August 19, 1968) , born Georgiy Antonovich Gamov (Георгий Антонович Гамов) was a Ukrainian born physicist and cosmologist. ... Atmospheric characteristics Atmospheric pressure trace Oxygen 100% Ganymede (IPA: , gan-i-meed, Greek Γανυμήδης) is Jupiters largest moon, and indeed the largest moon in the entire solar system; it is larger in diameter than Mercury but only about half its mass. ... Atmospheric characteristics Atmospheric pressure trace Oxygen 100% Ganymede (IPA: , gan-i-meed, Greek Γανυμήδης) is Jupiters largest moon, and indeed the largest moon in the entire solar system; it is larger in diameter than Mercury but only about half its mass. ... A gas giant is a large planet that is not composed mostly of rock or other solid matter. ... Pierre Gassendi (January 22, 1592 – October 24, 1655) was a French philosopher, scientist and mathematician, best known for attempting to reconcile Epicurean atomism with Christianity. ... Gassendi is a large lunar crater feature located at the northern edge of Mare Humorum. ... Louis Gathmann (August 11, 1843 - 1917), engineer and an inventor, started his career designing equipment for mills and farms and is notable for holding numerous patents. ... (help· info) (30 April 1777 – 23 February 1855) was a German mathematician and scientist of profound genius who contributed significantly to many fields, including number theory, analysis, differential geometry, geodesy, magnetism, astronomy and optics. ... Carl Friedrich Gauss expressed the gravitational constant in units of the solar system rather than SI units. ... Gegenschein (German for counterglow) is a faint brightening of the night sky in the region of the zodiac directly opposite the Sun caused by reflection of sunlight by small dust particles that lie in the plane of the Solar system. ... Margaret Geller discovered the Great Wall (astronomy) in 1989, with John Huchra based on redshift survey data from the CfA Redshift Survey. ... Gemini (Latin for twins, symbol , Unicode ♊) is one of the constellations of the zodiac. ... The Gemini Observatory is an astronomical observatory consisting of 8-metre telescopes at two different sites. ... The Geminids are a meteor shower caused by an object named 3200 Phaethon. ... In astronomy, many stars are referred to simply by catalogue numbers. ... General relativity (GR) is the geometrical theory of gravitation published by Albert Einstein in 1915. ... General relativity (GR) or general relativity theory (GRT) is the theory of gravitation published by Albert Einstein in 1915. ... The geocentric model (in Greek: geo = earth and centron = centre) of the universe is a paradigm which places the Earth at its center. ... This artistic representation of the geocentric model shows signs of the zodiac and the solar system with world at centre. ... The geocentric model (in Greek: geo = earth and centron = centre) of the universe is a paradigm which places the Earth at its center. ... In mathematics, a geodesic is a generalization of the notion of a straight line to curved spaces. Definition of geodesic depends on the type of curved space. If the space carries a natural metric then geodesics are defined to be (locally) the shortest path between points on the space. ... The GOCE project will measure high-accuracy gravity gradients and provide an accurate geoid model based on the Earths gravity field. ... A geomagnetic storm is a temporary disturbance of the Earths magnetosphere. ... George Gabriel Stokes Sir George Gabriel Stokes, 1st Baronet (13 August 1819–1 February 1903) was an Anglo-Irish mathematician and physicist. ... Father Georges-Henri Lemaître (July 17, 1894 – June 20, 1966) was a Belgian Roman Catholic priest and astronomer. ... A geostationary orbit (GSO) is a circular orbit directly above the Earths equator (0º latitude). ... Riccardo Giacconi (born October 6, 1931) is an Italian-born American Nobel Prize-winning astrophysicist. ... According to the Hertzsprung-Russell diagram, a red giant is a large non-main sequence star of stellar classification K or M; so-named because of the reddish appearance of the cooler giants. Examples include Aldebaran and Arcturus. ... The Giant Magellan Telescope is a ground-based telescope planned for completion in 2016. ... Giant Metrewave Radio Telescope (GMRT), located near Pune in India, is the worlds largest radio telescope at metre wavelengths. ... The Big Splash The giant impact theory (or Big Splash or Big Whack; cf. ... A dark nebula is a large cloud which appears as star-poor regions where the dust of interstellar medium seems to be concentrated. ... Giant star is a star that has stopped fusing hydrogen in its core. ... Giovanni Battista Riccioli (b. ... GJ 1061 (Gliese-Jahreiss 1061) is a star approximately 12. ... Gliese 876 is a red dwarf star (spectral type M4V) 15 light years from Earth in the constellation of Aquarius. ... Wilhelm Gliese (June 21, 1915 – June 12, 1993) was a German astronomer. ... In astronomy, many stars are referred to simply by catalogue numbers. ... A globular cluster is a spherical bundle of stars (star cluster) that orbits a galaxy as a satellite. ... Aerial view of Goddard Space Flight Center. ... Gold Medal awarded to Asaph Hall The Gold Medal is the highest award of the Royal Astronomical Society. ... Thomas Gold (May 22, 1920 – June 22, 2004) was an Austrian astrophysicist, a professor of astronomy at Cornell University, and a member of the US National Academy of Sciences. ... The Goldstone Deep Space Communications Complex (GDSCC) —commonly called the Goldstone Observatory— is located in Californias Mojave Desert (USA). ... Gottfried Wilhelm Leibniz (also von Leibni(t)z) (July 1 (June 21 Old Style) 1646, Leipzig – November 14, 1716, Hanover) was a German polymath, deemed a genius in his day and since. ... The telescope under construction in 2002. ... The Grand Interferometre a 2 Telescopes is an Optical Interferometer, on Plateau du Calern, Departement Fresnel, Observatoire de la Côte dAzur, France. ... In cosmology, assuming that nature is described by a GUT, the grand unification epoch was an era very, very soon after the Big Bang in which the temperature was comparable to the characteristic temperatures of grand unified theories. ... This article or section does not cite its references or sources. ... In physics, gravitation or gravity is the tendency of objects with mass to accelerate toward each other. ... The gravitational binding energy of an object is the amount of energy required to accelerate every component of that object to the escape velocity of every other component. ... This article or section does not cite its references or sources. ... According to the law of universal gravitation, the attractive force between two bodies is proportional to the product of their masses and inversely proportional to the square of the distance between them. ... The gravitational field is a field that causes bodies with mass to attract each other. ... This article covers the physics of gravitation. ... This article is in need of attention from an expert on the subject. ... A gravitational lens is formed when the light from a very distant, bright source (such as a quasar) is bent around a massive object (such as a massive galaxy) between the source object and the observer. ... This article is in need of attention from an expert on the subject. ... This article is in need of attention from an expert on the subject. ... It has been suggested that sling effect be merged into this article or section. ... In physics, gravitational radiation is energy that is transmitted through waves in the gravitational field of space-time, according to Albert Einsteins theory of general relativity: The Einstein field equations imply that any accelerated mass radiates energy this way, in the same way as the Maxwell equations that any... In physics, gravitational radiation is energy that is transmitted through waves in the gravitational field of space-time, according to Albert Einsteins theory of general relativity: The Einstein field equations imply that any accelerated mass radiates energy this way, in the same way as the Maxwell equations that any... In physics, the graviton is a hypothetical elementary particle that transmits the force of gravity in most quantum gravity systems. ... Gravity is a force of attraction that acts between bodies that have mass. ... To meet Wikipedias quality standards, this article or section may require cleanup. ... An image taken by the Hubble Space Telescope looking in the direction of the Great Attractor. ... NASAs series of Great Observatories satellites were four large, powerful space-based telescopes. ... The Great Red Spot as seen from Voyager 1 in 1979. ... The Great Wall is the largest known super-structure in the Universe. ... For the Brisbane bus routes known collectively as the Great Circle Line (598 & 599), see the following list of Brisbane Transport routes A great circle on a sphere A great circle is a circle on the surface of a sphere that has the same diameter as the sphere, dividing the... Green Bank Telescope: the largest fully steerable single dish in the world, 100 x 110 m. ... Greenwich (pronounced gren-itch , or by the locals) is a town, now part of the south eastern urban sprawl of London, on the south bank of the River Thames in the London Borough of Greenwich. ... Greenwich Mean Time (GMT) (aka the birthplace of Chuck Norris) is mean solar time at the Royal Greenwich Observatory in Greenwich, London, England, which by convention is at 0 degrees geographic longitude. ... The Gregorian telescope is a type of reflecting telescope designed by Scottish mathematician and astronomer, James Gregory in the 17th century. ... James Gregory James Gregory (November 1638 – October 1675), was a Scottish mathematician and astronomer. ... The Greisen-Zatsepin-Kuzmin limit (GZK limit) is a theoretical upper limit on the energy of cosmic rays from distant sources. ... Grigory Nikolaevich Neujmin (January 3, 1886 (Old Style: December 22, 1885) – December 17, 1946) (Russian: Григорий Николаевич Неуймин) was a Russian astronomer. ... Groombridge 1830 is a star. ... Galaxy groups and clusters are super-structures in the spread of galaxies of the cosmos. ... Definition GRS 80, or Geodetic Reference System 1980, is a geodetic reference system consisting of a global reference ellipsoid and a gravity field model. ... Grus (the crane) is a constellation. ... Grus (Latin for Crane) is a southern constellation. ... Alan H. Guth (born February 27, 1947) is a physicist and cosmologist. ...

H

NGC 604, a giant H II region in the Triangulum Galaxy. ... In stellar astronomy, the Hertzsprung-Russell diagram (usually referred to by the abbreviation H-R diagram or HRD) shows the relationship between absolute magnitude, luminosity, stellar classification, and surface temperature. ... In physics and astronomy, H-alpha, also written Hα, is a particular emission line created by hydrogen. ... Beta Centauri (β Cen / β Centauri), also known as Hadar or Agena, is the second brightest star in the constellation Centaurus and the eleventh brightest star in the nighttime sky. ... The Haemus Mountains are a mountain range on the Moon, located at the southwestern highland edge of the Mare Serenitatis Basin. ... The HALCA satellite is an 8 meter diameter radio telescope used for Very Long Baseline Interferometry. ... The Hale Telescope is the largest telescope at the Palomar Observatory. ... George Ellery Hale, Sc. ... The Half-Mile Telescope was constructed in 1968 (2 aerials) at the Mullard Radio Astronomy Observatory with 2 more aerials being added in 1972, using donated dishes (total cost was £70,000). ... Asaph Hall (October 15, 1829 – November 22, 1907) was an American astronomer who is most famous for having discovered the moons of Mars (namely Deimos and Phobos) in 1877. ... Portrait of Edmond Halley painted around 1687 by Thomas Murray (Royal Society, London) Edmond Halley a later portrait, by unknown artist. ... Halo around the sun at the South Pole (NOAA) Halos are optical phenomena that appear near or around the Sun or Moon, and sometimes near other strong light sources such as street lights. ... Hamal, also known as Alpha Arietis or 13 Arietis, is the brightest star in the constellation Aries. ... William Rowan Hamilton Sir William Rowan Hamilton (August 4, 1805 – September 2, 1865) was an Irish mathematician, physicist, and astronomer who made important contributions to the development of optics, dynamics, and algebra. ... Hannes Olof Gösta Alfvén (May 30, 1908; Norrköping, Sweden - April 2, 1995; Djursholm, Sweden) was a Swedish electrical power engineer. ... Hans Bethe in 1945. ... Harvard College Observatory, about 1900. ... In astronomy, many stars are referred to simply by catalogue numbers. ... The Haverah Park experiment was a cosmic ray air shower detection array consisting of water Cherenkov detectors distributed over an area of 12km² on Haverah Park in North Yorkshire Moors, UK. The experiment was operated by University of Leeds for 20 years until 1987 when it was switched off. ... In physics, Hawking radiation is thermal radiation thought to be emitted by black holes due to quantum effects. ... Stephen Hawking in 2005 Professor Stephen William Hawking, CH, CBE, FRS, (born January 8, 1942) is considered one of the worlds leading theoretical physicists. ... HD 209458b is an extrasolar planet that orbits the Sun-like star HD 209458 in the constellation Pegasus, some 150 light years from Earths solar system. ... HE0107-5240 is a newly discovered giant star roughly 36,000 light years away from Earth. ... The heat death is a possible final state of the universe, in which it has reached maximum entropy. ... The heat death is a possible final state of the universe, in which it has reached maximum entropy. ... Hegra is a small place in the middle of Norway, located in Stjørdal. ... Heka can refer to: An alternate spelling for either Hike or Heget in Egyptian mythology. ... The Helen B. Warner Prize for Astronomy is awarded annually by the American Astronomical Society for a significant contribution to observational or theoretical astronomy. ... Helene (hel-e-nee, Greek ‘Ελένη) is a moon of Saturn. ... The heliacal rising of a star (or other body such as the moon or a planet) occurs when it first becomes visible above the eastern horizon at dawn, after a period where it was hidden below the horizon or when it was just above the horizon but hidden by the... In astronomy, heliocentrism is the theory that the Sun is at the center of the Universe and/or the Solar System. ... In astronomy, heliocentrism is the theory that the Sun is at the center of the Universe and/or the Solar System. ... Heliocentric Solar System In astronomy, heliocentrism is the theory that the Sun is at the center of the Universe and/or the Solar System. ... The heliopause is the boundary between the heliosphere and the interstellar medium outside the solar system. ... Helios in Greek In earlier Greek mythology, the sun was personified as a deity called Hêlios (Greek for the sun), whom Homer equates with the sun titan Hyperion. ... A computer generated image showing the pattern of a p-mode solar acoustic oscillation both in the interior and on the surface of the sun. ... The heliosphere is a bubble in space produced by the solar wind. ... General Name, Symbol, Number Helium, He, 2 Atomic weight 4. ... NGC 7293, the Helix Nebula. ... The word hemisphere literally means half sphere or half ball; when used in the singular form, it refers to one of the halves of a spherical object. ... Henri Poincaré, photograph from the frontispiece of the 1913 edition of Last Thoughts Jules Henri Poincaré (April 29, 1854 – July 17, 1912), generally known as Henri Poincaré, was one of Frances greatest mathematicians and theoretical physicists, and a philosopher of science. ... The Henry Draper Catalogue is an astronomy catalogue with astrometric and spectroscopic data about more than 225,000 stars. ... The Henry Draper Medal was established by the widow of Henry Draper, and is awarded by the US National Academy of Sciences for contributions to astrophysics. ... Henry E. Holt is an American astronomer. ... The Henry Norris Russell Lectureship is awarded each year by the American Astronomical Society in recognition of a lifetime of excellence in astronomical research. ... For the son of Alexander the Great, see Heracles (Macedon). ... Herbig-Haro object HH47, imaged by the Hubble Space Telescope. ... Hercules is the fifth largest of the 88 modern constellations. ... Messier Object 13, the Great Globular Cluster in Hercules; one of the most prominent and best known globular clusters of the Northern celestial hemisphere. ... Herman of Carinthia, Hermanus Dalmata Herman of Carinthia (Slovene Herman KoroÅ¡ki) (Croatian Slav Dalmatian, or Herman Dalmatin) (Latin Sclavus Dalmata), was a Slovene (or perhaps a Croatian) philosopher, astronomer, astrologer, mathematician, translator and author. ... Hermann Mayer Salomon Goldschmidt (June 17, 1802 – April 26, 1866) was a German astronomer and painter who spent much of his life in France. ... Hermann von Helmholtz Hermann Ludwig Ferdinand von Helmholtz (August 31, 1821 – September 8, 1894) was a German physician and physicist. ... The Herschel Space Observatory is a mission of the European Space Agency. ... Caroline Lucretia Herschel Caroline Lucretia Herschel (March 16, 1750 – January 9, 1848) was a German-born English astronomer. ... John Herschel Sir John Frederick William Herschel (7 March 1792 – 11 May 1871) was an English mathematician and astronomer. ... William Herschel Sir Wilhelm Friedrich Herschel, FRS (November 15, 1738 – August 25, 1822) was a German-born British astronomer and composer who became famous for discovering the planet Uranus. ... Ejnar Hertzsprung (October 8, 1873, Copenhagen – October 21, 1967, Roskilde) was a Danish chemist and astronomer. ... The Hertzsprung-Russell diagram (usually referred to by the abbreviation H-R diagram or HRD, also known as a Colour-Magnitude (CM) diagram) shows the relationship between absolute magnitude, luminosity, classification, and surface temperature of stars. ... This article discusses the ancient Greek poet Hesiod. ... Johannes Hevelius Johannes Hevelius (Latin), also called (in German) Johann Hewelke or Johannes Hewel, or Jan Heweliusz (Polish), (born January 28, 1611 – died January 28, 1687), was a Polish [[1]], [[2]], [[3]], [[4]], councillor and mayor in GdaÅ„sk. ... Antony Hewish (born Fowey, Cornwall, May 11, 1924) is a British radio astronomer who won the Nobel Prize for Physics in 1974 (together with fellow radio-astronomer Martin Ryle) for his work on the development of radio aperture synthesis and its role in the discovery of pulsars. ... The High Energy Transient Explorer is an American astronomical satellite. ... The HiRes detector - an atmospheric fluorescence detector: HiRes currently consists of two sites on top of two mountains separated by 13km in western Utah. ... High energy astronomy is the study of astronomical objects that release EM radiation of highly energetic wavelengths. ... A high-mass X-ray binary (HMXB) is a binary star where one of the components is a neutron star or a black hole. ... In mathematics, a Hilbert space is a generalization of Euclidean space which is not restricted to finite dimensions. ... Atmospheric pressure 0 kPa Himalia (hye-mal-ee-a, also hi-mahl-ee-a, IPA , ; Greek ‘Ιμαλíα) is a moon of Jupiter. ... The Himalia group is a dynamical grouping of Jupiters moons, which share similar orbits. ... Hipparchus (Greek ) (ca. ... Hipparcos (for High Precision Parallax Collecting Satellite) was an astrometry mission of the European Space Agency (ESA) dedicated to the measurement of stellar parallax and the proper motions of stars. ... In astronomy, many stars are referred to simply by catalogue numbers. ... In astronomy, many stars are referred to simply by catalogue numbers. ... William Herschel knew as early as 1779 (Herschel 1805) that stars appeared much larger in telescopes than they really were but he did not know why. ... Astronomy is probably the oldest of the natural sciences, dating back to antiquity, with its origins in the religious practices of pre-history: vestiges of these are still found in astrology, a discipline long interwoven with astronomy, and not completely separate from it until about 1750‑1800 in the Western... The credit for the invention of the telescope has been a subject of discussion. ... Hoags Object is a non-typical galaxy of the type known as a ring galaxy. ... The Hobby-Eberly Telescope is a 9. ... The Mount Wilson Observatory (MWO) is an astronomical observatory in Los Angeles County, California. ... Horace Parnell Tuttle (March 24, 1839 - August 1923) was an American astronomer, and brother of Charles Wesley Tuttle. ... Horizon The horizon is the line that separates earth from sky. ... When we look at the CMB it comes from 15 billion light years away. ... The horizontal branch (HB) is a stage of stellar evolution which immediately follows the red giant branch. ... The horizontal coordinate system is a celestial coordinate system that uses the observers local horizon as the fundamental plane. ... For other types of horns, see horn (disambiguation). ... Horologium (Latin for clock) is one of the lesser southern constellations (declination around -60 degrees). ... In astrology, a horoscope is a chart or diagram representing the positions of the planets, other celestial bodies, and sensitive angles at the time of any event, such as a persons birth. ... The Horrendous Space Kablooie is an alternate term for the Big Bang, coined by Bill Watterson in his comic strip Calvin and Hobbes. ... Jeremiah Horrocks (c. ... IC 434, the Horsehead Nebula. ... Hot dark matter is a form of dark matter, which consists of particles that travel with relativistic velocities. ... In astronomy, an objects hour angle (HA) is defined as the difference between the current local sidereal time (LST) and the right ascension () of the object: HAobject = LST - object Thus, the objects hour angle indicates how much sidereal time has passed since the object was on the local... MyCn18, the Hourglass Nebula. ... Friedrich Georg Houtermans (January 22, 1903 - March 1, 1966) was a physicist born in Zoppod near Danzig (today Gdansk, Poland). ... Sir Fred Hoyle Sir Fred Hoyle (June 24, 1915 in Bingley, Yorkshire – August 20, 2001 in Bournemouth, England) was a British astronomer, notable for a number of his theories that run counter to current astronomical opinion, and a writer of science fiction, including a number of books co-authored by... The Hubble Deep Field The Hubble Deep Field (HDF) is the result of a series of observations by the Hubble Space Telescope of a small region of the northern celestial hemisphere. ... Hubbles law is the statement in astronomy that the redshift in light coming from distant galaxies is proportional to their distance. ... With the rising estimated cost to service the Hubble Space Telescope, an international team led by Johns Hopkins University astronomers suggests an alternative: create a new space telescope, called the Hubble Origins Probe (HOP), that would carry instruments built for the canceled servicing mission. ... The Hubble Space Telescope (HST) is a telescope in orbit around the Earth. ... Hubbles law is the statement in astronomy that the redshift in light coming from distant galaxies is proportional to their distance. ... In cosmology, the Hubble expansion is the motion of galaxies away from each other, due to the expansion of the universe. ... It has been suggested that this article or section be merged with Galaxy classification. ... Hubbles law is the statement in physical cosmology that the redshift in light coming from distant galaxies is proportional to their distance. ... Edwin Hubble Edwin Powell Hubble (November 20, 1889 – September 28, 1953) was an American astronomer, noted for his discovery of galaxies beyond the Milky Way and the cosmological Redshift. ... John Huchra discovered the Great Wall (astronomy) in 1989, with Margaret Geller based on redshift survey data from the CfA Redshift Survey. ... William Huggins Sir William Huggins, OM , FRS (February 7, 1824 – May 12, 1910) was a British astronomer. ... Russell Alan Hulse (born November 28, 1950) is an American physicist and winner of the Nobel Prize in Physics, shared with his thesis advisor Joseph Hooton Taylor Jr. ... Milton Lasell Humason (August 19, 1891 – June 18, 1972) was as American astronomer. ... A scale replica of the probe An artists impression of the Huygens probe as it descends through Titans murky, brownish-orange atmosphere of nitrogen and carbon-based molecules, beaming its findings to the distant Cassini orbiter. ... Christiaan Huygens Christiaan Huygens (pronounced in English (IPA): ; in Dutch: ) (April 14, 1629–July 8, 1695), was a Dutch mathematician and physicist; born in The Hague as the son of Constantijn Huygens. ... The Hyades (‘Υάδες) are an open star cluster located in the constellation Taurus. ... Hydra is the largest of the 88 modern constellations, and was also one of the 48 constellations listed by Ptolemy. ... Hydrus (Latin for Hydra, also referred to as male Hydra or little Hydra) is a minor southern constellation. ... Hyperion (hye-peer-ee-É™n, IPA , Greek Ὑπερίων) is a moon of Saturn discovered by William Cranch Bond, George Phillips Bond and William Lassell in 1848. ... A hypernova is a theoretical type of supernova produced when an exceptionally large star collapses at the end of its lifespan. ... In particle physics, the baryons are a family of subatomic particles including the proton and the neutron (collectively called nucleons), as well as a number of unstable, heavier particles (called hyperons). ... Hypothetical planets are planets that have been suggested as possibly existing (or have been believed to exist), but have never been proven to actually exist. ...

I

I Sin Yi Xing (Yi-xing) (一行) (683 – 727) was a Chinese astronomer and buddhist monk of the Tang Dynasty. ...

Iapetus (eye-ap-i-tus, Greek Ιαπετός) (British spelling: Japetus) is the third-largest moon of Saturn, discovered by Giovanni Domenico Cassini in 1671. ... Logo of the IAU The International Astronomical Union (French: Union astronomique internationale) unites national astronomical societies from around the world. ... Icy moons are believed to be a common class of planetoids that have a surface mostly of ice, possibly with an ocean under the ice, and possibly including a rocky core of silicate or metallic rocks. ... Ijiraq (ee-ye-raak or ee-ji-raak) is a natural satellite of Saturn. ... Immanuel Kant (22 April 1724 – 12 February 1804), was a German philosopher from Königsberg (now Kaliningrad) in East Prussia. ... Tycho crater on Earths moon. ... Artists impression of a major impact event. ... Inclination in general is the angle between a reference plane and another plane or axis of direction. ... Indigo is the color of light between 440 to 420 nanometres in wavelength, placing it between blue and violet. ... // Definition Inductance is a measure of the amount of magnetic flux produced for a given electric current. ... Indus is a southern constellation that is supposed to represent an American Indian. ... Eclipses may occur repeatedly, separated by some specific interval of time: this interval is called an eclipse cycle. ... The terms inferior planet and superior planet were coined by Copernicus to distinguish a planets orbits size in relation to the Earths. ... The terms inferior planet and superior planet were coined by Copernicus to distinguish a planets orbits size in relation to the Earths. ... The inflationary epoch is the term used in cosmology to describe the brief time in the very early universe when, according to inflation theory, the universe was expanding exponentially. ... The Infrared Optical Telescope Array (IOTA) began with an agreement in 1988 among five Institutions, the Smithsonian Astrophysical Observatory, Harvard University, the University of Massachusetts, the University of Wyoming, and MIT/Lincoln Laboratory, to build a two-telescope stellar interferometer for the purpose of making fundamental astrophysical observations, and also... The Infrared Space Observatory (ISO)is a space telescope for infrared light designed and operated by the European Space Agency (ESA). ... Infrared astronomy is the branch of astronomy and astrophysics which deals with objects visible in infrared (IR) radiation. ... The inner satellites of Jupiter are four small moons that orbit close to Jupiter, merging with its planetary ring. ... The term Institute of Astronomy or IoA is conventionally used by astronomers to refer to the Institute of Astronomy at the University of Cambridge (although there are departments at other universities with the same name). ... The Instituto de Astrofísica de Canarias is an astrophysical research institute based on Tenerife in the Canary Islands, Spain. ... In calculus, the integral of a function is a generalization of area, mass, volume and total. ... The integrated Sachs Wolfe effect is a change in the fluctuations of the temperature of the cosmic microwave background due to evolution of the Universe according to the standard Big Bang model. ... Intensity is a widely-used term, which can mean: In colloquial use: Strength Amplitude Level In physics: Intensity, power per unit area (W/m2) Field strength of electric, magnetic, or electromagnetic fields. ... An intensity interferometer is the name given to devices that use the Hanbury-Brown and Twiss effect. ... An Interacting binary star is a type of double star in which one or both of the component stars has filled or exceeded its Roche lobe. ... Intercalation is the insertion of an extra day or month into some calendar years to make the calendar follow the seasons. ... Intercalation is the insertion of an extra day or month into some calendar years to make the calendar follow the seasons. ... Intercalation is the insertioffn of an extra day, week or month into some calendar years to make the calendar follow the seasons. ... Interferometry is the applied science of combining two or more input points of a particular data type, such as optical measurements, to form a greater picture based on the combination of the two sources. ... Interferometry is the applied science of combining two or more input points of a particular data type, such as optical measurements, to form a greater picture based on the combination of the two sources. ... Intergalactic space is the physical space between galaxies. ... Logo of the IAU The International Astronomical Union (French: Union astronomique internationale) unites national astronomical societies from around the world. ... Temps Atomique International (TAI) or International Atomic Time is a very accurate and stable time scale. ... The International Earth Rotation and Reference Systems Service is the body responsible for maintaining global time and reference frame standards, notably through its Earth Orientation Parameter (EOP) and International Celestial Reference System (ICRS) groups. ... International Space Station insignia ISS Statistics Crew: 2 As of March 5, 2006 Perigee: 352. ... ISR Certificate The International Star Registry (ISR) was founded in 1979 and allows people to name a star as a gift or memorial. ... The Interplanetary Scintillation Array (IPS Array or Pulsar Array) was built at the Mullard Radio Astronomy Observatory in 1967 and originally covered four acres (16,000 m²). It was extended in 1978 to nine, and re-furbished in 1989. ... Interstellar cloud is the generic name given to accumulations of gas and dust in our galaxy. ... Interstellar cloud is the generic name given to accumulations of gas and dust in our galaxy. ... The distribution of ionized hydrogen (known by astronomers as H II (aitch two) from old spectroscopic terminology) in the parts of the Galactic interstellar medium visible from the Earths northern hemisphere (from the Wisconsin H-Alpha Mapper Survey) In astronomy, the interstellar medium (or ISM) is the matter and... Introduction to Geomagnetically Trapped Radiation was written by Martin Walt in 1994. ... Atmospheric characteristics Atmospheric pressure trace Sulfur dioxide 90% Io (eye-oe, IPA: , Greek Ῑώ) is the innermost of the four Galilean moons of Jupiter. ... The ionosphere is the part of the atmosphere that is ionized by solar radiation. ... IPCC is science authority for the UNFCCC The Intergovernmental Panel on Climate Change (IPCC) was established in 1988 by two United Nations organizations, the World Meteorological Organization (WMO) and the United Nations Environment Programme (UNEP) to assess the risk of human-induced climate change. The Panel is open to all... IRAF stands for the Image Reduction and Analysis Facility. ... The Infrared Astronomical Satellite (IRAS) was a space-based observatory that performed a survey of the entire sky at infrared wavelengths. ... NGC1427A, an example of an irregular galaxy. ... An irregular variable is a type of variable star in which variations in brightness show no regular periodicity. ... Ali Ben Isa was an Arab astronomer in the 9th century. ... The INT dome by moonlight The Isaac Newton Telescope or INT is a 2. ... In complex analysis, a branch of mathematics, an isolated singularity is a singularity which contains no other singularities close to it. ... The Italian Space Agency (Agenzia Spaziale Italiana or ASI) was founded in 1988 to promote, co-ordinate and conduct space activities in Italy. ... Ithaca Chasma is a huge valley on Saturns moon Tethys. ...

J

The J2000. ... The J2000. ... The Jacobus Kapteyn Telescope or JKT was a 1m optical telescope of the Isaac Newton Group of Telescopes on La Palma in the Canary Islands. ... James Clerk Maxwell (13 June 1831 – 5 November 1879) was a Scottish mathematical physicist, born in Edinburgh. ... The James Clerk Maxwell Telescope (JCMT) is a 15-metre submillimetre-wavelength telescope at Mauna Kea Observatory in Hawaii. ... The James Webb Space Telescope (JWST) is a planned orbital infrared observatory, intended (in part) to replace the aging Hubble Space Telescope. ... In radio astronomy, the flux unit or jansky (symbol Jy) is a non-SI unit of electromagnetic flux equivalent to 10−26 watts per square metre per hertz. ... Image:Jansky. ... Janus (jay-nus, Greek Ιανός) is a moon of Saturn. ... Sir James Hopwood Jeans (born Ormskirk, September 11, 1877, died Dorking, September 16, 1946) was a British physicist, astronomer and mathematician who was the first to propose the theory of continuous creation of matter in the universe. ... Roger Clifton Jennison worked as a radio astronomer at Jodrell Bank under the guidance of Robert Hanbury Brown. ... The Caltech Jet Propulsion Laboratory (JPL), in La Cañada Flintridge, near Pasadena, California, USA, builds and operates unmanned spacecraft for the National Aeronautics and Space Administration (NASA). ... The 76m Lovell Telescope at Jodrell Bank Observatory. ... The 76m Lovell Telescope at Jodrell Bank Observatory. ... Sir Harold Spencer Jones (March 29, 1890 – November 3, 1960) was a British astronomer. ... From top: Neptune, Uranus, Saturn, and Jupiter. ... The Julian calendar was introduced in 46 BC by Julius Caesar and took force in 45 BC (709 ab urbe condita). ... The Julian calendar was introduced in 46 BC by Julius Caesar and took force in 45 BC (709 ab urbe condita). ... The Julian day or Julian day number (JDN) is the number of days that have elapsed since 12 noon Greenwich Mean Time (UT or TT) on Monday, January 1, 4713 BC (in the proleptic Julian calendar; or November 24, 4714 BC in the proleptic Gregorian calendar). ... The Julian day or Julian day number (JDN) is the number of days that have elapsed since 12 noon Greenwich Mean Time (UT or TT) on Monday, January 1, 4713 BC in the proleptic Julian calendar . ... A Julian epoch is an epoch that is based on Julian years of exactly 365. ... A Julian year is the length of an average year in the Julian calendar, 365. ... Atmospheric pressure 0 kPa Juliet (jew-lee-et ) is a moon of Uranus. ... Atmospheric characteristics Atmospheric pressure 70 kPa Hydrogen ~86% Helium ~14% Methane 0. ... Jupiter has 63 known natural satellites. ... To meet Wikipedias quality standards, this article or section may require cleanup. ...

K

The spectrum of K-type asteroids resembles CV and CO meteorites. ... The tree of life Kabbalah (קבלה Reception, Standard Hebrew Qabbala, Tiberian Hebrew Qabbālāh; also written variously as Cabala, Cabalah, Cabbala, Cabbalah, Kabala, Kabalah, Kabbala, Qabala, Qabalah) is a religious philosophical system claiming an insight into divine nature. ... In physics, Kaluza-Klein theory (or KK theory, for short) is a model which sought to unify the two fundamental forces of gravitation and electromagnetism. ... Kamacite is a mineral. ... Kapteyns Star (also known as GJ 191, HD 33793 or CD -45 1841) is a class M0 subdwarf discovered by Jacobus Kapteyn in 1897. ... Jacobus Cornelius Kapteyn, (January 19, 1851 – June 18, 1922) was a Dutch astronomer, best known for his extensive studies of the Milky Way and as the first discoverer of evidence for galactic rotation. ... JJ Kavelaars is a Canadian astronomer who was part of a team that discovered several moons of Jupiter, Saturn, Uranus, and Neptune. ... This article needs to be wikified. ... The Mauna Kea Observatory, an institute of the University of Hawaii, is considered one of the most important land-based observatories in the world for its isolated, unobstructed views of space without interference from man-made light sources. ... The W. M. Keck Observatory is home to the two largest optical/near-infrared telescopes at the 4,145 meter (13,600 ft) summit of Mauna Kea in Hawaii. ... James Edward Keeler (September 10, 1857 – August 12, 1900) was an American astronomer. ... The Kelvin-Helmholtz mechanism is an astronomical event that occurs when the surface of a star or a planet cools. ... Kenneth S. Russell is an Australian astronomer. ... Johannes Keplers primary contributions to astronomy/astrophysics were his three laws of planetary motion. ... Johannes Kepler Johannes Kepler (December 27, 1571 – November 15, 1630), a key figure in the scientific revolution, was a German mathematician, astrologer, astronomer, and an early writer of science fiction stories. ... Johannes Keplers primary contributions to astronomy/astrophysics were the three laws of planetary motion. ... Tomb of Omar Khayyám, Nishapur, Iran. ... Kidinnu (also Kidunnu) (circa 400 BC – possibly 14 August 330 BC) was a Chaldean astronomer and mathematician. ... Kirkwood gaps are gaps that appear in a graph if we classify the asteroids according to their periods, which is proportional to their mean radius from the Sun. ... Daniel Kirkwood (September 27, 1814 - June 11, 1895) was an American astronomer. ... The Kitt Peak National Observatory (KPNO) is a United States astronomical observatory located on a 2,096 m (6,880 ft) peak of the Quinlan Mountains in the Arizona-Sonoran Desert on the Tohono Oodham Nation, 88 kilometres (55 miles) southwest of Tucson. ... Kiviuq (kee-vee-oek or kiv-ee-uk) is a natural satellite of Saturn. ... The title given to this article is incorrect due to technical limitations. ... The Kölner Observatorium für SubMillimeter Astronomie (KOSMA) is a 3-m radio telescope located at 3,135 m on Gornergrat near Zermatt (Switzerland). ... Kristian Birkeland Kristian Birkeland (December 13, 1867 - June 15, 1917) was born in Christiania (Oslo today) and wrote his first scientific paper at the age of 18. ... Kruger 60 is a binary star system composed of A and B components, both of which are red dwarf stars. ... Screenshot of KStars showing the night sky from Hanover. ... Categories: Astronomy stubs | Astronomical observatories ... Artists rendering of the Kuiper Belt and hypothetical more distant Oort cloud. ... Gerard Kuiper, circa 1963. ...

L

L-type asteroids are relatively uncommon asteroids with a strongly reddish spectrum shortwards of 0. ... La Silla Observatory is an astronomical observatory in Chile with eighteen telescopes. ... French astronomer, graduated from the grande école SupOptique (École supérieure doptique), he is the inventor of the interferometric astronomy. ... Lacaille 9352 (Lac 9352) is a red dwarf with a very high proper motion (6. ... Abbé Nicolas Louis de Lacaille (March 15, 1713 – March 21, 1762) was a French astronomer. ... Lacerta, being Latin for Lizard, is one of the 88 official constellations acknowledged by the International Astronomical Union. ... Lacus Aestatis (latin for Summer Lake) consists of two relatively small areas of lunar mare located near the western limb of the Moon. ... Lacus Autumni (latin for Lake of Autumn) is a region of lunar mare that lies near the western limb of the Moon. ... The prominent crater is Macrobius crater, and to its northwest is the small Lacus Bonitatis. ... Mare Vaporum (the sea of vapors) is a lunar mare located between the southwest rim of Mare Serenitatis and the southeast rim of Mare Imbrium. ... Lacus Felicitatis (latin for Lake of Happiness) is a small patch of the lunar surface that has been inundated by flows of lava, leaving a level patch with a lower albedo than the surrounding ground. ... Mare Vaporum (the sea of vapors) is a lunar mare located between the southwest rim of Mare Serenitatis and the southeast rim of Mare Imbrium. ... Mare Vaporum (the sea of vapors) is a lunar mare located between the southwest rim of Mare Serenitatis and the southeast rim of Mare Imbrium. ... Mare Vaporum (the sea of vapors) is a lunar mare located between the southwest rim of Mare Serenitatis and the southeast rim of Mare Imbrium. ... Lacus Mortis, latin for Lake of Death, is a plain of basaltic-lava flows in the northeastern part of the Moon. ... Mare Vaporum (the sea of vapors) is a lunar mare located between the southwest rim of Mare Serenitatis and the southeast rim of Mare Imbrium. ... Firmicus is a lunar crater that lies in the eastern part of the Moons near side, so that from Earth it appears oval in shape due to foreshortening. ... Lacus Solitudinus (latin for Lake of Solitude) is a small lunar mare on the far side of the Moon. ... Lacus Somniorum is a small plain located in the northeastern part of the Moons near side. ... Lacus Spei (latin for Lake of Hope) is a small lunar mare that is located in the northeastern part of the Moons near side. ... Lacus Temporis (latin for Lake of Time) is a small lunar mare that is located in the northeastern quadrant of the Moons near side. ... The Lagoon Nebula (also known as M8 and NGC 6523) is a giant interstellar cloud and H II region, in the constellation Sagittarius. ... Joseph Louis Lagrange Joseph Louis Lagrange (January 25, 1736 – April 10, 1813; born Giuseppe Luigi Lagrangia in Turin, Lagrange moved to Paris (1787) and became a French citizen, adopting the French translation of his name, Joseph Louis Lagrange) was an Italian mathematician and astronomer who made important contributions to classical... Lagrangian mechanics is a re-formulation of classical mechanics introduced by Joseph Louis Lagrange in 1788. ... The Lagrangian points (IPA: ; also Lagrange point, L-point, or libration point), are the five positions in interplanetary space where a small object affected only by gravity can theoretically be stationary relative to two larger objects (such as a satellite with respect to the Earth and Moon). ... Lalande 21185 is a red dwarf star approximately 2. ... ΛCDM or Lambda-CDM is an abbreviation for Lambda-Cold Dark Matter. ... Johann Heinrich Lambert Johann Heinrich Lambert (August 26, 1728 – September 25, 1777), was a mathematician, physicist and astronomer. ... Cornelius Lanczos, born Kornél Löwy (February 2, 1893–June 25, 1974), was a Hungarian mathematician and physicist. ... Samuel Pierpont Langley. ... Joseph Louis Lagrange (January 25, 1736 – April 10, 1813) was an Italian mathematician and astronomer who later lived in France and Prussia. ... Johan Philip Lansberg (August 25, 1561–December 8, 1632) was a Dutch astronomer. ... Johan Philip Lansberg (August 25, 1561–December 8, 1632) was a Dutch astronomer. ... Pierre-Simon Laplace. ... LBT on the cover of VMEbus Systems magazine The Large Binocular Telescope (originally named the Columbus Project) is a joint project of the Italian astronomical community (represented by the Istituto Nazionale di Astrofisica (INAF)), the University of Arizona, Arizona State University, Northern Arizona University, the LBT Beteiligungsgesellschaft in Germany (Max... The Large Magellanic Cloud (also known as LMC) is a dwarf galaxy that is in orbit around our own Milky Way galaxy. ... A Large liquid mirror telescope or (Large LMT) is a technology being pursued by NASA and the University of British Columbia (UBC). ... Astronomy and cosmology examine the universe to understand the large-scale structure of the cosmos. ... A simulated view of Larissa orbiting Neptune Larissa (la-ris-a, Greek Λάρῑσα) is the fifth of Neptunes known moons. ... William Lassell (June 18, 1799 – October 5, 1880) was a British astronomer, born in Bolton, Greater Manchester, England. ... Latitude, usually denoted symbolically by the Greek letter φ, gives the location of a place on Earth north or south of the Equator. ... Light path in a Cassegrain reflector Laurent Cassegrain was a Catholic priest born in the region of Chartres around 1629 and died at Chaudon (Eure-et-Loir) on August 31, 1693. ... It has been suggested that this article or section be merged into Gravity. ... The LBT LBT on the cover of VMEbus Systems magazine Forest fire approaches the LBT in July 2004 The Large Binocular Telescope (originally named the Columbus Project) is a joint project of the Italian astronomical community (represented by the Instituto Nazionale di Astrofisica (INAF)), the University of Arizona, Arizona State... Urbain Le Verrier. ... Henrietta Swan Leavitt (July 4, 1868 – December 12, 1921) was an American astronomer, as well as being deaf [1] and a Christian [2]. She was born in Lancaster, Massachusetts. ... Atmospheric pressure 0 kPa Leda (lee-da, IPA , Greek Λήδα) is a satellite of Jupiter that was discovered by Charles T. Kowal at the Mount Palomar Observatory on September 14, 1974, right after three nights worth of photographic plates had been taken (September 11 through 13; Leda appears on all of... The Low Energy Gamma-Ray Imager (LEGRI) is a payload for the first mission of the Spanish MINISAT platform. ... The Leiden Observatory (Sterrewacht Leiden) is an optical observatory in the city of Leiden in the Netherlands. ... Father Georges-Henri Lemaître (July 17, 1894 – June 20, 1966) was a Belgian Roman Catholic priest and astronomer. ... A lens. ... Lens sag is a problem that sometimes afflicts very large reflecting telescopes. ... The Spindle Galaxy (NGC 5866), a lenticular galaxy in the Draco constellation. ... Leo (Latin for lion, symbol , Unicode ♌) is a constellation of the zodiac. ... Leo Minor (Latin for Small Lion) is a rather dim constellation that can barely be recognized as a triangle and lies between the easily discerned constellations Ursa Major and Leo. ... 1966 Leonid Meteor Shower The Leonids are a prolific meteor shower associated with the comet Tempel-Tuttle. ... Lepus (Latin for Hare) is a constellation, lying just south of Orion, and possibly representing a hare being chased by him. ... Leuschner Observatory is the student observatory of the University of California, Berkeley. ... David H. Levy (born 1948) is a Canadian astronomer and science writer most famous for his co-discovery of Comet Shoemaker-Levy 9, which collided with the planet Jupiter in 1994. ... Libra (Latin for balance, symbol , Unicode ♎) is a constellation of the zodiac. ... Although the Moon keeps the same side towards Earth, careful observations will reveal you can actually see 59% of the Moons surface. ... The Lick Observatory is an astronomical observatory, owned and operated by the University of California. ... In astronomy, a light curve is a graph of light intensity as a function of time. ... This photo of New York City shows excessive Sky glow, one form of light pollution, partly caused by many unshielded lights. ... A light year, abbreviated ly, is the distance light travels in one year: roughly 9. ... Light-time correction is a slight angular shift in the apparent position of a celestial object, especially a planet, from its geometric position on the celestial sphere caused by the objects motion during the time it takes its light to reach Earth. ... The LIGO Hanford Control Room LIGO stands for Laser Interferometer Gravitational-Wave Observatory. ... The word linear comes from the Latin word linearis, which means created by lines. ... Hans Lippershey (Wesel 1570– Middelburg 1619) was a Dutch lensmaker. ... The LISA is the Laser Interferometer Space Antenna experiment. ... This is a list of numbered asteroids, in sequential order. ... Famous astronomers and astrophysicists include: Contents: Top - 0–9 A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A Marc Aaronson (USA, 1950 – 1987) George Ogden Abell (USA, 1927 – 1983) Antonio Abetti (Italy... Current Performance of Ground-Based Interferometers Here is a list of currently existing astronomical interferometers, and some parameters describing their performance. ... There are probably a few thousand astronomical objects named after people. ... An astrophysicist is a person whose profession is astrophysics. ... Bright stars can be bright because they produce more light, because they are closer to us, or both. ... Non-periodic comets are seen only once. ... Here is a list of the 88 modern constellations by their area in the sky, measured in square degrees. ... This is a list of the craters on the Moon. ... List of galaxies: Abell 1835 IR1916 AM 0644-741 Andromeda Galaxy (M31/NGC 224) Andromeda I Andromeda II Andromeda III Aquarius Dwarf Barnards Galaxy (NGC 6822) Black Eye Galaxy (M64/NGC 4826) Bodes Galaxy (M81/NGC 3031) Canis Major Dwarf Galaxy Carina Dwarf Centaurus A Galaxy Draco Dwarf Fornax... Here is a list of the largest optical reflecting telescopes sorted by mirror diameter. ... Paris 1900 exposition refractor. ... External links ALPO meteor showers list SPA meteor showers list Categories: Meteor showers ... The following is a list of mnemonics for stellar classification. ... This is a list of molecules that have been detected in the interstellar medium, as of 2003. ... This list of the nearest stars to Earth is ordered by increasing distance out to a maximum of 5 parsecs (16. ... Non-periodic comets are seen on only one occasion. ... The following is a list of astronomical observatories, along with initial dates of operation and location, if available. ... Several hundred more observatories (many optical) are listed here. ... The following is the IAUs list of periodic comets that have a number designation. ... // Classical mechanics Philosophiae Naturalis Principia Mathematica Isaac Newton Description: The Philosophiae Naturalis Principia Mathematica (Latin: mathematical principles of natural philosophy, often Principia or Principia Mathematica for short) is a three-volume work by Isaac Newton published on July 5, 1687. ... Related topics List of observatories Radio telescopes A more complete list of radio telescopes can be found by looking at the radio telescopes category External links AstroSurf. ... This is a list of semiregular variable stars. ... Below is a list of solar system objects with diameter >500km: The Sun, a spectral class G2 star Mercury Venus Earth Moon Mars Jupiter Io Europa Ganymede Callisto complete list of Jupiters natural satellites Saturn Tethys Dione Rhea Titan Iapetus complete list of Saturns natural satellites Uranus Ariel... This is a list of Solar system objects by mass, in decreasing order. ... This is a list of solar system objects by radius, in decreasing order. ... The following is a partial list of stars which have their own articles in Wikipedia. ... The following are lists of stars with confirmed extrasolar planets. ... There are three main types of astronomical telescopes - and these are divided into subgroups. ... Ursa Minor is a constellation in the northern sky, the name of which means Small Bearin Latin. ... The Liverpool Telescope is a 2m fully robotic telescope, meaning that it can be remotely operated and also run without human intervention once given a list of observations to make. ... Llano de Chajnantor Observatory is an astronomical observatory located at 5104 m altitude in the Chilean Atacama desert, 50 kilometers to the north of San Pedro de Atacama. ... Nikolay Ivanovich Lobachevsky Nikolai Ivanovich Lobachevsky (Никола́й Ива́нович Лобаче́вский) (December 1, 1792–February 24, 1856 (N.S.); November 20, 1792–February 12, 1856 (O.S.))) was a Russian mathematician. ... Map of the local group The Local Group is the group of galaxies that includes our galaxy, the Milky Way. ... The Virgo Supercluster or Local Supercluster is the supercluster of galaxies that contains the Local Group and with it our galaxy, the Milky Way. ... LOFAR is the Low Frequency ARray for radio astronomy. ... The Lomonosov Gold Medal, named after Russian scientist and polymath Mikhail Lomonosov, is awarded each year since 1959 for outstanding achievements in the natural sciences and the humanities by the USSR Academy of Sciences and later the Russian Academy of Sciences (RAS). ... A long period variable is a type of variable star in which variations in brightness occur over long timescales of months or years. ... Longitude, sometimes denoted by the Greek letter λ, describes the location of a place on Earth east or west of a north-south line called the Prime Meridian. ... The Longitude of the ascending node () is one of the orbital elements used to specify the orbit of an object in space. ... The longitude prize was a prize offered by the British government in 1714 for the precise determination of a ships longitude. ... Loop quantum gravity (LQG), also known as loop gravity and quantum geometry, is a proposed quantum theory of spacetime which attempts to reconcile the seemingly incompatible theories of quantum mechanics and general relativity. ... The LOPES project (LOFAR Prototype Station) is a cosmic ray detector array, located in Karlsruhe, Germany, and is operated in coincidence with an existing, well calibrated air shower experiment called KASCADE. There are different ways to observe cosmic rays, or, more accurately, the air showers that cosmic rays produce when... Lord Rosse William Parsons, 3rd Earl of Rosse (June 17, 1800 – October 31, 1867) was an Irish astronomer. ... A Lorentz transformation (LT) is a linear transformation that preserves the spacetime interval between any two events in Minkowski space, while leaving the origin fixed. ... The Lorentz transformation (LT), named after its discoverer, the Dutch physicist and mathematician Hendrik Antoon Lorentz (1853-1928), forms the basis for the special theory of relativity, which has been introduced to remove contradictions between the theories of electromagnetism and classical mechanics. ... Painting of Hendrik Lorentz by Arnhemensis Hendrik Antoon Lorentz (July 18, 1853, Arnhem – February 4, 1928, Haarlem) was a Dutch physicist and the winner of the 1902 Nobel Prize in Physics for his work on electromagnetic radiation. ... ... A plot of the trajectory Lorenz system for values r=28, σ = 10, b = 8/3 The Lorenz attractor, introduced by Edward Lorenz in 1963, is a non-linear three-dimensional deterministic dynamical system derived from the simplified equations of convection rolls arising in the dynamical equations of the atmosphere. ... Edward Norton Lorenz (born May 23, 1917), a research meteorologist at MIT, observed that minute variations in the initial values of variables in his primitive computer weather model (c. ... The 76m Lovell Telescope at Jodrell Bank Observatory. ... A Low Earth Orbiting satellite (or LEO satellite) is a satellite in an orbit that has a semi-major axis that is less than that of a geostationary orbit. ... Low-mass X-ray binaries (LMXBs) are binary stars where one of the components is either a black hole or neutron star. ... The Clark Dome at Mars Hill. ... Percival observing Mars from the Lowell Observatory. ... In the Lunar geologic timescale, the Lower Imbrian epoch occurred between 3850 million years ago to about 3800 million years ago. ... The best 1% of exposures of the 0. ... Luminance (also called luminosity) is a photometric measure of the density of luminous intensity in a given direction. ... The luminiferous aether: it was hypothesised that the Earth moves through a medium of aether that carries light In the late 19th century luminiferous aether (light-bearing aether) was the term used to describe a medium for the propagation of light. ... Luminosity has different meanings in several different fields of science. ... Luminosity distance DL is defined in terms of the relationship between the absolute magnitude M and apparent magnitude m of an astronomical object: which gives: Calculating the luminosity distance of an object correctly from its real distance is quite complex, but there are a number of useful webpages for performing... The term Luna can refer to the Earths Moon. ... Luna 9 was an unmanned space mission of the Soviet Unions Luna program. ... Bulk composition of the moons mantle and crust estimated, weight percent Oxygen 42. ... A lunar calendar is a calendar whose date indicates the moon phase. ... In celestial navigation, lunar distance is in the angle of the Moons centre from the Sun or from the bright stars. ... An eclipse refers to the phenomenon of one body passing into the shadow cast by another body. ... The lunar geologic timescale (or perhaps more properly the selenologic timescale) divides the history of Earths Moon into six generally recognized geologic periods: Copernician Period : 1100 MY to present Eratosthenian Period : 3200 MY to 1100 MY Upper Imbrian Epoch : 3800 MY to 3200 MY Lower Imbrian Epoch : 3850 MY... A map showing the location of Mare Imbrium The Lunar maria (singular: mare, pronounced MAH-ray) are large, dark, basaltic plains on Earths Moon, formed by ancient basaltic flood eruptions caused by extremely large meteoroid impacts. ... Lunar Meteorite Allan Hills 81005 A Lunar meteorite is a meteorite that is known to have originated on the Moon. ... The lunar nodes are the orbital nodes of the Moon, that is, the points where the orbit of the Moon crosses the ecliptic (which is the apparent path of the Sun across the heavens against the background stars). ... In astronomy, a phase of the Moon is any of the aspects or appearances presented by the Moon as seen from Earth, determined by the portion of the Moon that is visibly illuminated by the Sun. ... The moons elliptical orbit precesses about once in just under 9 years. ... Lunation is the mean time for one lunar phase cycle (i. ... A lunisolar calendar is a calendar whose date indicates both the moon phase and the time of the solar year. ... Precession refers to a change in the direction of the axis of a rotating object. ... Lupus (Latin for Wolf) is a southern constellation. ... Lupus (Latin for Wolf) is a southern constellation. ... In astronomy, many stars are referred to simply by catalogue numbers. ... Aleksandr Mikhailovich Lyapunov (Александр Михайлович Ляпунов) (June 6, 1857 – November 3, 1918, all new style) was a Russian mathematician, mechanician and physicist. ... The Lyman alpha Forest is the sum of absorption lines seen in spectra of distant galaxies and quasars, beginning from the Lyman alpha line at 121. ... Lynx is a constellation of the northern hemisphere, introduced in the 17th century by Johannes Hevelius. ... A Lyot filter, named for its inventor Bernard Lyot, is a type of optical filter that uses birefringence to produce a narrow passband of transmitted wavelengths. ... Bernard Ferdinand Lyot (February 27, 1897 – April 2, 1952) was a French astronomer. ... Lyra (Latin for Lyre) is one of the 48 constellations listed by Ptolemy, and is one of the 88 modern constellations recognized by the International Astronomical Union. ... Atmospheric pressure 0 kPa Lysithea (lye-sith-ee-a or li-sith-ee-a, IPA , ; Greek Λυσιθέα) is a moon of Jupiter. ...

M

M-theory is a solution proposed for the unknown theory of everything which would combine all five superstring theories and 11-dimensional supergravity together. ... M-theory is a cutting-edge theory of physics that deals with the extension of superstring theory. ... M-type asteroids are metallic asteroids; they are moderately bright (albedo . ... Spiral Galaxy M100 (also known as Messier Object 100, Messier 100, M100 or NGC 4321) is a spiral galaxy in the Coma Berenices constellation. ... The Pinwheel Galaxy (also known as Messier Object 101, or NGC 5457) is a spiral galaxy in the constellation Ursa Major. ... Messier Object 104, the Sombrero Galaxy. ... Globular Cluster M107 (also known as Messier Object 107, Messier 107, M107 or NGC 6171) is a very loose globular cluster in the Ophiuchus constellation. ... Messier Object 13, the Great Globular Cluster in Hercules; one of the most prominent and best known globular clusters of the Northern celestial hemisphere. ... Messier Object 27, the Dumbbell Nebula The Dumbbell Nebula (also known as Messier Object 27, M27, or NGC 6853) is a planetary nebula in the Vulpecula constellation, at a distance of about 1250 light years. ... This image is a Galaxy Evolution Explorer observation of the large galaxy in Andromeda, Messier 31. ... Messier Object 33, the Triangulum Galaxy. ... M41 is a gearbox from Volvo. ... The entire Orion Nebula in visible light Optical images reveal clouds of gas and dust in the Orion Nebula; an infrared image (right) reveals the new stars shining within. ... The Pleiades are an open cluster dominated by hot blue stars surrounded by reflection nebulosity The Pleiades (also known as M45 or the Seven Sisters) is an open cluster in the constellation of Taurus. ... Elliptical Galaxy M49 (also known as Messier Object 49, Messier 49, M49, or NGC 4472) is an elliptical galaxy in the Virgo constellation. ... Categories: Stub | Messier objects | NGC objects | Planetary nebulae ... Spiral Galaxy M58 (also known as Messier Object 58, Messier 58, M58, or NGC 4579) is a spiral galaxy in the Virgo constellation. ... Elliptical Galaxy M59 (also known as Messier Object 59, Messier 59, M59, or NGC 4621) is an elliptical galaxy in the Virgo constellation. ... The term M60 can refer to several things: The M60 motorway The M60 Patton tank The M60 machine gun An astronomical object, see Messier 60 BMW M60, a BMW piston engine This is a disambiguation page — a navigational aid which lists other pages that might otherwise share the same title. ... Spiral Galaxy M61 (also known as Messier Object 61 or NGC 4303) is a large spiral galaxy of type SABbc in the Virgo Cluster. ... Bodes Galaxy, also known as M81 and NGC 3031, is a spiral galaxy located 12 million light years from Earth in the Ursa Major constellation. ... The M81 group of galaxies (or simply the M81 group) is a physical group and a galaxy cluster. ... Messier object 82, the Cigar Galaxy. ... The Lenticular Galaxy M84 (also known as Messier Object 84, Messier 84, M84, or NGC 4374) is a lenticular galaxy in the Virgo constellation. ... The Lenticular Galaxy M86 (also known as Messier Object 86, Messier 86, M86, or NGC 4406) is a lenticular galaxy in the Virgo constellation. ... The jet emitted by M87 in this image is thought to be caused by a supermassive black hole at the galaxys center. ... M90 refers to: Messier 90 a Messier object and a spiral galaxy in the Virgo constellation. ... BITCH!111 ... This article is in need of attention from an expert on the subject. ... Wikipedia does not yet have an article with this exact name. ... The Magdalena Ridge Observatory Interferometer will be an optical array composed of ten telescopes, each approximately 1. ... The Magellan Telescopes are 6. ... The two Magellanic Clouds are irregular dwarf galaxies orbiting our Milky Way galaxy, and thus are members of our Local Group of galaxies. ... MAGIC is the Major Atmospheric Gamma-ray Imaging Cherenkov Telescope. ... Artists conception of a magnetar, with magnetic field lines A magnetar is a neutron star with an extremely strong magnetic field, the decay of which powers the emission of copious amounts of high-energy electromagnetic radiation, particularly X-rays and gamma-rays. ... A magnetopause flows along the boundary between a magnetic field, (see: magnetosphere) and surrounding plasma. ... Schematic of Earths magnetosphere. ... In science, a magnitude is the numerical size of something: see orders of magnitude. ... An order of magnitude is the class of scale or magnitude of any amount, where each class contains values of a fixed ratio to the class preceding it. ... The asteroid belt is a region of the solar system falling roughly between the planets Mars and Jupiter where the greatest concentration of asteroid orbits can be found. ... Hertzsprung-Russell diagram The main sequence of the Hertzsprung-Russell diagram is the curve where the majority of stars are located in this diagram. ... Invented by the Russian optician Dmitri Maksutov (1896-1964), the Maksutov reflecting telescope is a type of catadioptric telescope that uses a spherical primary mirror in conjunction with a meniscus-shaped corrector plate at the entrance pupil in order to correct spherical aberration. ... Named after Russian optician Dmitri Maksutov (1896-1964), the Maksutov telescope is a type of Cassegrain reflecting telescope that uses a spherical primary mirror in conjunction with a meniscus-shaped correcting plate at the entrance pupil in order to correct for spherical aberration. ... Invented by the Russian optician Dmitri Maksutov (1896-1964), the Maksutov-Cassegrain reflecting telescope is a type of catadioptric telescope that uses a either a spherical or parabolic primary mirror in conjunction with a meniscus-shaped corrector plate at the entrance pupil in order to correct spherical aberration. ... On a sphere, the sum of the angles of a triangle is not equal to 180°. A sphere is not a Euclidean space. ... Marcus Manilius (fl. ... // The many-worlds interpretation (or MWI) is an interpretation of quantum mechanics that rejects the non-deterministic and irreversible wavefunction collapse associated with measurement in the Copenhagen interpretation in favor of a description in terms of quantum entanglement and reversible time evolution of states. ... Image:Geoff marcy. ... Mare Anguis (the serpent sea) is a lunar mare located on the near side of the Moon, about 150 miles in diameter. ... Mare Australe (the southern sea) is a lunar mare located in the southeastern hemisphere of the Moon. ... Mare Cognitum (the sea that has become known) is a lunar mare located in a basin or large crater which sits in the second ring of the Procellarum basin. ... Mare Crisium Studios is also the name of a company formed to develop the game Stars! Supernova Genesis. ... Mare Fecunditatis (the sea of fecundity) is a lunar mare 909 miles in diameter. ... Mare Frigoris (the sea of cold) is a lunar mare located just north of Mare Imbrium, and stretches east to north of Mare Serenitatis. ... Mare Humboldtianum (Latin for sea of Alexander von Humboldt) is a lunar mare located within the Humboldtianum basin, just to the east of Mare Frigoris. ... Mare Humorum (the sea of moisture) is a lunar mare. ... Oblique view of Mare Imbrium looking south towards Copernicus crater. ... Located on the Moons southern hemisphere, Mare Ingenii (sea of cleverness) is one of the few lunar mare features on the far side of the Moon. ... Mare Insularum (the sea of islands) is a lunar mare located in the Insularum basin just south of Mare Imbrium. ... Mare Marginis (sea of the eagle) is a lunar mare that lies on the very edge of the lunar nearside. ... Mare Moscoviense (sea of Muscovy) is a lunar mare that sits in the Moscoviense basin. ... The Sea of Nectar (Mare Nectaris) is a small lunar mare or sea (a volcanic lava plain noticeably darker than the rest of the moons surface) located between the Sea of Tranquillity (Mare Tranquillatis) and the Sea of Fecundity (Mare Fecunditatis). ... The Sea of Clouds of the Moon. ... 1967 photograph made by NASAs Lunar Orbiter 4 Like a target ring bulls-eye, the lunar mare Mare Orientale (the eastern sea) is one of the most striking large scale lunar features. ... A map of Mare Serenitatis. ... Mare Smythii (sea of William Henry Smyth) is a lunar mare located along the equator on the easternmost edge of the lunar near side. ... Mare Spumans (the foaming sea) is a lunar mare located just south of Mare Undarum on the lunar near side. ... The Sea of Tranquility of the Moon. ... Mare Undarum (the sea of waves) is a lunar mare located just north of Mare Spumans on the lunar near side. ... Mare Vaporum (the sea of vapors) is a lunar mare located between the southwest rim of Mare Serenitatis and the southeast rim of Mare Imbrium. ... Simon Marius Simon Marius (January 10, 1573 – December 26, 1624) was a German astronomer. ... Mars is the fourth planet from the Sun in the solar system, named after the Roman god of war (the counterpart of the Greek Ares), on account of its blood red color as viewed in the night sky. ... Concept model of the Mars Express spacecraft Mars Express is a Mars exploration mission of the European Space Agency and the first planetary mission attempted by the agency. ... Computer generated image of Global Surveyor spacecraft (NASA) The Mars Global Surveyor (MGS) is an American spacecraft. ... The Mars Pathfinder was launched on December 4, 1996 by NASA aboard a Delta II rocket, just a month after the Mars Global Surveyor was launched. ... A Mars-crosser asteroid is an asteroid whose orbit crosses that of Mars. ... Aerial view of the test area at Marshall Space Flight Center The George C. Marshall Space Flight Center (MSFC) is a lead NASA center for propulsion, Space Shuttle propulsion, external fuel tank, crew training and payloads, International Space Station (ISS) design and construction, for computers, networks, and information management. ... A Martian meteorite is a meteorite that has landed on Earth but is believed to have originated from Mars. ... An astrophysical maser is a naturally occurring source of stimulated spectral line emission, typically in the microwave portion of the electromagnetic spectrum. ... Nevil Maskelyne. ... An extinction event (also extinction-level event, ELE) is a period in time when a large number of species die out. ... Mass transfer is the phrase commonly used in engineering for physical processes that involve molecular and convective transport of atoms and molecules within physical systems. ... Mass-energy equivalence is where mass has an energy equivalence, and energy has a mass equivalence. ... Massive compact halo object, or MACHO, is a general name for any kind of astronomical body that might explain the apparent presence of dark matter in galaxy halos. ... The Mauna Kea Observatory, an institute of the University of Hawaii, is considered one of the most important land-based observatories in the world for its isolated, unobstructed views of space without interference from man-made light sources. ... The Mauna Loa Solar Observatory (MLSO) is a collection of solar imaging instruments located on the island of Hawaii, USA. General Information The MLSO is operated by the High Altitude Observatory, which is a division of the National Center for Atmospheric Research. ... The Maunder minimum in a 400 year history of sunspot numbers The Maunder Minimum is the name given to the period roughly from 1645 to 1715 A.D., when sunspots became exceedingly rare, as noted by solar observers of the time. ... Michel Mayor (born 12 January 1942) is a professor in the Department of Astronomy at the University of Geneva. ... Pierre Louis Maupertuis, here wearing lapmudes or a fur coat from his Lapland expedition. ... What is the MRT? The Mauritius Radio Telescope (MRT) is a synthesis radio telescope that is used to make images of the sky at a frequency of 151. ... Max Born Max Born (born December 11, 1882 in Breslau, died January 5, 1970 in Göttingen) was a German mathematician and physicist of Jewish heritage. ... Michel Mayor (born 12 January 1942) is a professor at the Department of Astronomy at the University of Geneva. ... Leander McCormick Observatory in 1890 The McCormick Observatory is one of the astronomical observatories operated by the Astronomy Department of the University of Virginia and is situated in Charlottesville, Virginia (USA). ... Sir William Hunter McCrea (13 December 1904 – April 25, 1999) was an astronomer and mathematician. ... The McMath-Pierce Solar Telescope The McMath-Pierce Solar Telescope is a 1. ... In the study of orbital dynamics the mean anomaly is a measure of time, specific to the orbiting body p, which is a multiple of 2π radians at and only at periapsis. ... Solar time is based on the idea that, when the sun reaches its highest point in the sky, it is noon. ... Solar time is based on the idea that, when the sun reaches its highest point in the sky, it is noon. ... Solar time is based on the idea that, when the sun reaches its highest point in the sky, it is noon. ... The megaparsec (abbreviated Mpc) is a unit of distance used in astronomy, equal to one million parsecs. ... Megrez is the star Delta Ursae Maioris. ... Mensa (Latin for Table) is a southern constellation which was first introduced by Nicolas Louis de Lacaille under the name Mons Mensae (Latin for table mountain). ... MER-B (Opportunity) is the second of the two rovers of NASAs Mars Exploration Rover Mission. ... Merak (β Ursae Majoris, HD 95418) is a star in the constellation of Ursa Major, forming a part of The Plough or Big Dipper. ... The Mercator Telescope is a 1. ... Nicholas (Nikolaus) Mercator (c. ... Atmospheric characteristics Atmospheric pressure trace Potassium 31. ... This article is about the astronomical concept. ... On the earth, a meridian is a north-south line between the North Pole and the South Pole. ... Merlin Ambrosius (Welsh: Myrddin Emrys; also known as Myrddin Wyllt (Merlin the wild), Merlin Caledonensis (Scottish Merlin), Merlinus, and Merlyn) is the personage best known as the mighty wizard featured in accounts of Arthur of Britain starting with Geoffrey of Monmouths Historia Regum Britanniae. ... Messier marathon is an attempt undertaken by amateur astronomers to find as many Messier objects as possible during one night. ... Table of all 110 Messier objects. ... Charles Messier Charles Messier (June 26, 1730 – April 12, 1817) was a French astronomer who in 1774 published a catalogue of 45 deep sky objects such as nebulae and star clusters. ... In astronomy, it is common to speak of the chemical makeup of substances in terms of hydrogen, helium, and metals, i. ... In astronomy and cosmology, the term metal or metal-rich is used to refer to any element heavier than hydrogen and helium. ... In astronomy, the metallicity of an object is the proportion of its matter made up of chemical elements other than hydrogen and helium. ... A burst of meteors A meteor is the visible path of a meteoroid that enters the Earths (or another bodys) atmosphere, commonly called a shooting star or falling star. ... Leonid Meteor Shower From earliest times, humankind has noticed flurries of meteors that seemed to emanate from particular points in the sky at particular times of the year. ... A meteorite is a small extraterrestrial body that impacts the Earths surface. ... Meteorites are classified according to their structure and mineral composition. ... A meteoroid is a relatively small (sand- to boulder-sized) fragment of debris in the Solar System. ... Discovery image of Methone Methone (me-thoe-nee, Greek Μεθωνη) is a natural satellite of Saturn. ... Atmospheric pressure 0 kPa Metis (IPA: , mee-tis, Greek Μήτις) is the innermost member of the Jupiters small inner moons. ... Meton of Athens was a mathematician, astronomer and engineer who lived in Athens in the 5th century BCE. He is best known for the 19-year Metonic Cycle which he introduced into the Athenian luni-solar calendar as a method of calculating dates. ... The Metonic cycle or Enneadecaeteris in astronomy and calendar studies is a particular approximate common multiple of the tropical year and the synodic month. ... In mathematics, a metric space is a set where a notion of distance between elements of the set is defined. ... Miaplacidus (placid waters) is one of the brightest stars in Earths night sky, with apparent magnitude 1. ... John Michell (1724 – April 29, 1793) was an English natural philosopher and geologist, whose work was rediscovered in the 1970s. ... The Michelson-Morley experiment, one of the most important and famous experiments in the history of physics, was performed in 1887 by Albert Michelson and Edward Morley at what is now Case Western Reserve University, and is considered by some to be the first strong evidence against the theory of... Microquasars are smaller cousins of quasars. ... Categories: Astronomy stubs | Modern constellations | Constellations ... The Microvariability and Oscillations of STars telescope or the MOST space observatory is Canadas first and (as of mid-2005) only space telescope. ... Milankovitch cycles is the name given to the collective effect of changes in the Earths movements upon its climate. ... Note: This article contains special characters. ... The Milky Way (a translation of the Latin Via Lactea, in turn derived from the Greek Galaxia Kuklos; or simply the Galaxy) is a barred spiral galaxy in the Local Group, and has special significance to humanity as the location of the solar system, which is located near the Orion... Bernard Mills built the two-dimensional Mills Cross Telescope in the early 1950s. ... Atmosphere none Mimas (mye-mÉ™s, IPA , Greek Μίμᾱς, rarely Μίμανς) is a moon of Saturn that was discovered in 1789 by William Herschel. ... In physics and mathematics, Minkowski space (or Minkowski spacetime) is the mathematical setting in which Einsteins theory of special relativity is most conveniently formulated. ... The Minor Planet Center operates at the Smithsonian Astrophysical Observatory (SAO), which is part of the Center for Astrophysics (CfA) along with the Harvard College Observatory (HCO). ... Minor planets, or planetoids are minor bodies of the Solar system orbiting the Sun (or of other planetary systems orbiting other stars) that are larger than meteoroids (the largest of which might be taken to be around 10 meters or so across) but smaller than major planets (Mercury having a... Mintaka, also known as δ Orionis, is one of the three stars of the belt of the Orion constellation. ... A minute of arc, arcminute, or MOA is a unit of angular measurement, equal to one sixtieth (1/60) of one degree. ... Mir (Мир, which can mean both world and peace in Russian) was a highly successful Soviet (and later Russian) space station. ... Chandra X-ray Image of Mira Mira (ο Cet / 68 Ceti / HD14386 / HIP10826 / ADS 1778 AP / Omicron Ceti) is a binary star in the constellation Cetus consisting of the red giant, Mira A or just Mira, and a white dwarf, Mira B or VZ Ceti. ... Mira variables are a class of pulsating variable stars characterized by very red colors, pulsation periods longer than 100 days, and light amplitudes greater than one magnitude. ... Mirach is the common name of β Andromedae, a star in the Andromeda constellation. ... Atmospheric pressure 0 kPa Miranda (mi-ran-da) is the smallest and innermost of Uranus major moons. ... Mirfak (also known as Algenib, and designated α Persei) is the brightest star in the constellation of Perseus. ... Mizar (ζ UMa / ζ Ursae Majoris / Zeta Ursae Majoris) is a star in the constellation Ursa Major, lying just at the corner of the Big Dippers handle. ... Wikipedia does not yet have an article with this exact name. ... The MMT Observatory at sunset The MMT Observatory (MMTO) is an astronomical observatory located on Mount Hopkins, Arizona, USA (55km south of Tucson) in the Santa Rita Mountains. ... The term modern geocentrism refers to a belief currently held by certain groups that the Earth is the center of the universe and does not move. ... In physics, the modified Newtonian dynamics (MOND) is a burgeoning theory that attempts to explain the galaxy rotation problem by modifying Newtons second law of motion. ... A Molecular cloud is a type of interstellar cloud whose density and size permits the formation of molecular hydrogen, H2. ... Molecular hydrogen, H2, is a molecule formed from two atoms of hydrogen. ... The Molongolo Cross Telescope was a 408 MHz radio telescope built by Bernard Mills and collaborators and operated by the University of Sydney. ... The Molonglo Observatory Synthesis Telescope (MOST) is a radio telescope operating at 843 MHz. ... Monoceros (Latin for Unicorn) is a faint constellation on the winter night sky, surrounded by Orion to the west, Gemini to the north, Canis Major to the south and Hydra to the east. ... A monocular is a modified refracting telescope used to magnify the images of distant objects by passing light through a series of lenses and prisms; the use of prisms results in a lightweight telescope. ... Mons Ida is a mountain on Amalthea, one of Jupiters smallest moons. ... Mons Lyctas is a mountain on one of Jupiters smallest moons Amalthea. ... The Apennine Mountains of the Moon. ... Montes Carpatus is a mountain range that forms the southern edge of the Mare Imbrium on the Moon. ... The Caucasus mountain range on the Moon lies along the eastern edge of Mare Imbrium. ... Montes Cordillera is a mountain range on the Moon. ... The Montes Pyrenaeus are a mountain range on the Moon, bordering Mare Nectaris. ... The Riphaeus Mountains are a mountain range on the Moon that borders Mare Cognitum, part of the rim of Cognitum basin. ... Montes Rook is a ring-shaped mountain range that lies along the western limb of the Moon, crossing over to the far side. ... Bulk composition of the moons mantle and crust estimated, weight percent Oxygen 42. ... In astronomy, a phase of the Moon is any of the aspects or appearances presented by the Moon as seen from Earth, determined by the portion of the Moon that is visibly illuminated by the Sun. ... Sir Patrick Moore presenting The Sky at Night, October 2005 Sir Patrick Alfred Caldwell-Moore, CBE, FRS, FRAS (born March 4, 1923) is an amateur astronomer who has attained an important position in British astronomy as a writer, organizer and presenter of the subject. ... Palomar Observatory is a privately-owned observatory located in San Diego County, California, 90 miles (145 km) southeast of Mount Wilson Observatory, on Palomar Mountain. ... The old administration building with the dome of the Farnham telescope The dome of the 50-inch Great Melbourne telescope Mount Stromlo Observatory (MSO) located just outside of Canberra, Australia, is part of the Research School of Astronomy and Astrophysics at the Australian National University (ANU). ... The Mount Wilson Observatory (MWO) is an astronomical observatory in Los Angeles County, California. ... The Monitoring X-ray Experiment (MOXE) is an X-ray all-sky monitor to be launched on the Russian Spectrum-X-Gamma satellite. ... Jean Mueller is an American astronomer. ... Mullard Radio Astronomy Observatory is home to a number of large aperture synthesis radio telescopes, including the One-Mile Telescope, 5km Ryle Telescope, and the Arcminute Microkelvin Imager. ... A binary star system consists of two stars both orbiting around their barycenter. ... // A multiverse (or meta-universe) is the hypothetical set of multiple possible universes (including our universe) that together comprise all of physical reality. ... Mundilfari (moon-dil-fair-ee, Norse Mundilfäri) (Saturn XXV) is a natural satellite of Saturn. ... Murzim is Arabic for The Herald, probably heralding Sirius in the night sky. ... Musca (Latin for Fly) is one of the minor southern constellations. ... J. H. von Mädler. ... Pierre François André Méchain (August 16, 1744 – September 20, 1804) was a French astronomer. ... August Ferdinand Möbius (November 17, 1790, Schulpforta, Saxony, Germany - September 26, 1868, Leipzig) was a German mathematician and theoretical astronomer. ... Johannes Müller von Königsberg (June 6, 1436 – July 6, 1476), known by his Latin pseudonym Regiomontanus, was an important German mathematician, astronomer and astrologer. ...

N

The n-body problem is the problem of finding, given the initial positions, masses, and velocities of n bodies, their subsequent motions as determined by classical mechanics, i. ... Nabu-rimanni (also spelled Naburianos, Naburiannuos, Naburiannu, Naburimannu or Naburimani) (c. ... The nadir (from Arabic nazir, opposite) is the astronomical term for the point in the sky directly below the observer, or more precisely, the point in the sky with an altitude of -90°. Geometrically, it is the point on the celestial sphere intersected by a line drawn from the observer... A simulated view of Naiad orbiting Neptune with The Sun in the distance. ... In abstract mathematics, naive set theory1 was the first development of set theory, which was later to be framed more carefully as axiomatic set theory. ... A naked eye is a figure of speech, referring to human eyes unaided by enhancing equipment such as a telescope or binoculars. ... blah blah blah, some people believe God made the universe and that is all there is. ... Nançay Radio Telescope primary mirror. ... Naos (nay-os, from the Greek ναύσ ship, also known as Suhail Hadar, Zeta Puppis or ζ Puppis), a white supergiant in the constellation of Puppis, is one of the brightest stars in the Milky Way, in terms of absolute magnitude. ... John Napier John Napier (1550–April 4, 1617) was a Scottish mathematician, physicist and astronomer. ... The Narrabri Stellar Intensity Interferometer was the first astronomical instrument to measure the diameters of a large number of stars at visible wavelengths. ... Narvi (nar-vee) (Saturn XXXI) is a natural satellite of Saturn. ... This article or section does not cite its references or sources. ... The National Optical Astronomy Observatory consists of four observatories under one management structure: Kitt Peak National Observatory Cerro Tololo Inter-American Observatory Gemini Observatory National Solar Observatory See also: List of observatories External link http://www. ... The National Radio Astronomy Observatory (NRAO) is an institution set up by the United States government for the purpose of radio astronomy. ... Moons of solar system scaled to Earths Moon A natural satellite is a moon (not capitalized), that is, any natural object that orbits a planet. ... First title page, November 4, 1869 Nature is one of the oldest and most reputable scientific journals, first published on 4 November 1869. ... There are several traditions of navigation. ... The Navy Prototype Optical Interferometer (NPOI) is an interferometer operated by the US Naval Observatory, the Naval Research Laboratory and The Lowell Observatory. ... Near Earth Asteroid Eros as seen from the NEAR spacecraft. ... Near-Earth asteroids (NEAs) are asteroids whose orbits are close to Earths orbit. ... Near-Earth objects (NEO) are asteroids, comets and large meteoroids whose orbit intersects Earths orbit and which may therefore pose a collision danger. ... The Triangulum Emission Nebula NGC 604 lies in a spiral arm of Galaxy M33, 2. ... A planetary disc forming in the Orion Nebula. ... The Nectarian Period of the lunar geologic timescale runs from 3920 million years ago to 3850 million years ago. ... Nemesis is the name given to a hypothetical red dwarf star or brown dwarf, orbiting the Sun at a distance of about 50,000 to 100,000 AU, somewhat beyond the Oort cloud. ... Atmospheric characteristics Surface pressure ≫100 MPa Hydrogen - H2 80% ±3. ... Neptune has 13 known moons. ... Voyager 2 view of Nereid. ... The neutrino is an elementary particle. ... Neutrino oscillation is a quantum mechanical phenomenon whereby a neutrino created with a specific lepton flavor (electron, muon, or tau) can later be measured to have a different flavor. ... Neutron stars are one of the few possible endpoints of stellar evolution. ... Neutronium is a term used in science fiction and popular literature to refer to an extremely dense phase of matter composed primarily of neutrons. ... Rolf Herman Nevanlinna (October 22, 1895, Joensuu - May 28, 1980, Helsinki) is perhaps the most famous Finnish mathematician. ... The New General Catalogue (NGC) is the most well-known catalogue of deep sky objects in amateur astronomy. ... New Horizons is a NASA unmanned mission to fly by Pluto and its moons. ... The New Technology Telescope, or NTT is a 3. ... The lunar phase depends on the Moons position in orbit around Earth. ... Newcombs Tables of the Sun is the short title for a work by the American astronomer and mathematician Simon Newcomb entitled Tables of the Motion of the Earth on its Axis and Around the Sun on pages 1-169 of volume VI of the serial publication Astronomical Papers prepared... Simon Newcomb. ... Newtons First and Second laws, in Latin, from the original 1687 edition of the Principia Mathematica. ... Sir Isaac Newton, PRS, (4 January 1643 – 31 March 1727) [OS: 25 December 1642 – 20 March 1727] was an English physicist, mathematician, astronomer, alchemist, inventor, and natural philosopher who is generally regarded as one of the most influential scientists in history. ... The original version of the physical discipline of mechanics, due to Sir Isaac Newton, who developed the theory over a period from about 1664, until the publication of his great work, known as the Principia, in 1687. ... Classical mechanics is a model of the physics of forces acting upon bodies. ... Newtonian Telescope The Newtonian telescope is a type of reflecting telescope invented by the British scientist Sir Isaac Newton (1643-1727), using a parabolic primary mirror and a flat diagonal secondary mirror. ... The James Webb Space Telescope (JWST) is a planned orbital infrared observatory, intended (in part) to replace the aging Hubble Space Telescope. ... Spiral Galaxy M77. ... NGC 2264 is the designation number of the New General Catalogue that identifies two astronomical objects as a single object: the Cone Nebula and the Christmas Tree Cluster. ... NGC 3227 is a Seyfert galaxy. ... Spiral Galaxy M100 (also known as Messier Object 100, Messier 100, M100 or NGC 4321) is a spiral galaxy in the Coma Berenices constellation. ... The jet emitted by M87 in this image is thought to be caused by a supermassive black hole at the galaxys center. ... VLA and Optical image of the Centaurus A Galaxy. ... Globular Cluster M107 (also known as Messier Object 107, Messier 107, M107 or NGC 6171) is a very loose globular cluster in the Ophiuchus constellation. ... Chandra image of NGC 6420. ... Categories: | | | ... Seyfert Galaxy NGC 7742 imaged by the Hubble Telescope. ... The James Webb Space Telescope (JWST) is a planned orbital infrared observatory, intended (in part) to replace the aging Hubble Space Telescope. ... The main cupola The 76-cm refractor at Nice Observatory The Nice Observatory (Observatoire de Nice) is located in Nice, France on the summit of Mont Gros. ... Seth Barnes Nicholson (November 12, 1891 – July 2, 1963) was an American astronomer. ... The Niels Bohr Institute is part of the Niels Bohr Institute for Astronomy, Physics and Geophysics of the University of Copenhagen. ... Amateur astronomy, often called back yard astronomy, is a hobby whose participants enjoy observing celestial objects. ... Nikola Tesla (July 10, 1856 - c. ... Peter Nilson (1937 - 1998) was a Swedish astronomer and novelist. ... The National Optical Astronomy Observatory (NOAO) consists of four observatories under one management structure: Kitt Peak National Observatory Cerro Tololo Inter-American Observatory Gemini Observatory National Solar Observatory It is run by the Association of Universities for Research in Astronomy (AURA), with a cooperative agreement with the National Science Foundation... A node is one of two points where a bodys orbit crosses the ecliptic, called the ascending node (when the body is moving northward) and descending node (when the body is moving southward). ... Behavior of lines with a common perpendicular in each of the three types of geometry The term non-Euclidean geometry (also spelled: non-Euclidian geometry) describes both hyperbolic and elliptic geometry, which are contrasted with Euclidean geometry. ... A non-standard cosmology is a cosmological framework that fundamentally contradicts one of the basic aspects of the big bang model of physical cosmology. ... The dome of the Nordic Optical Telescope. ... Norma (Latin for Normal, i. ... Compass rose with north highlighted and at top North is one of the four cardinal directions, specifically the direction that, in Western culture, is treated as the primary direction: north is used (explicitly or implicitly) to define all other directions; the (visual) top edges of maps usually correspond to the... Amateur astronomers photo of the North America Nebula The North America Nebula (also known as NGC 7000) is an emission nebula in the constellation Cygnus, close to Deneb (the tail of the swan and its brightest star). ... The North Star is a title of the star best suited for navigation northwards. ... The Northeastern Space Radio Observatory or Radio-Observatorio Espacial do Nordeste (ROEN) is a VLBI Antenna located at Fortaleza, Brazil. ... Insert non-formatted text here The Northern Hemisphere is the half of a planets surface (or celestial sphere) that is north of the equator (the word hemisphere literally means half ball). On the Earth, the Northern Hemisphere contains most of the land and population. ... This article needs to be cleaned up to conform to a higher standard of quality. ... Domenico Maria Novara (Ferrara, 1454-1504) was an astronomer and for 21 years was a professor at Bolognas university, where he became famous as Nicolaus Copernicus teacher. ... Igor Dmitrievich Novikov (И́горь Дми́триевич Но́виков) (born November 10, 1935) is a Russian theoretical astrophysicist and cosmologist. ... Pyotr Sergeyevich Novikov (August 15, 1901 - January 9, 1975) was a Russian mathematician who was born in Moscow, Russia and died in Moscow, Russia. ... The Nuclear Spectroscopic Telescope Array, or NuSTAR, is future space-based X-ray telescope. ... Nucleocosmochronology is the study of the evolution of the Universe with respect to the four fundamental processes of Nucleosynthesis. ... Nucleosynthesis is the process of creating new atomic nuclei either by nuclear fusion or nuclear fission. ... Rotation (green), Precession (blue) and Nutation (red) of the Earth Nutation is a slight irregular motion (etymologically a nodding) in the axis of rotation of a largely axially symmetric object, such as a gyroscope or a planet. ...

O

The rare O-type asteroids have spectra similar to the unusual asteroid 3628 Boznemcová, which is the best asteroid match to the spectra of L6 and LL6 ordinary chondrite meteorites. ... The Oak Ridge Observatory is operated by the Harvard-Smithsonian Center for Astrophysics as a facility of the Smithsonian Astrophysical Observatory (SAO), and houses the largest telescope east of Texas in the United States, a 61-inch reflector. ... Atmospheric pressure 0 kPa Oberon (oe-bur-on) is the outermost of the major moons of the planet Uranus. ... Oberth (in front) with fellow ABMA employees Hermann Julius Oberth (June 25, 1894 - December 28, 1989) was a German physicist and one of the founding fathers of rocketry and astronautics. ... Oblate also refers to a member of the Roman Catholic religious order of the Missionary Oblates of Mary Immaculate, or in some cases to a lay or religious person who has officially associated himself (or herself) with a monastic community such as the Benedictines for reasons of personal enrichment without... The Obliquity of the ecliptic is the angle between the plane of the Earths equator and the ecliptic plane in which the Earth rotates around the Sun. ... Obruchev is a disintegrating lunar crater that lies along the southern shore of Mare Ingenii, on the far side of the Moon. ... Observation is an activity of an intelligent living being, to sense and assimiliate the knowledge of a phenomenon in its framework of previous knowledge and ideas. ... Moletai Astronomical Observatory An observatory is a location used for observing terrestrial and/or celestial events. ... The Observatorio del Teide is an astronomical observatory on Tenerife operated by the Instituto de Astrofísica de Canarias. ... Categories: Strasbourg | Stub ... In this July, 1997 still frame captured from video, the bright star Aldebaran has just reappeared on the dark limb of the waning crescent moon in this predawn occultation. ... The Ocean of Storms of the Moon. ... Octans (Latin for octant) is an inconspicuous constellation introduced by Nicolas Louis de Lacaille. ... Odysseus is the huge, shallow crater on the right Odysseus is the largest crater on Saturns moon Tethys. ... The OGS (Optical Ground Station) telescope, installed in the Teide Observatory, has been built by Carl Zeiss, is owned by ESA (European Space Agency) and is operated by the IAC (Instituto de Astrofísica de Canarias). ... Olbers paradox, described by the German astronomer Heinrich Wilhelm Olbers in 1826 and earlier by Johannes Kepler in 1610 and Halley and Cheseaux in the 18th century, is the paradoxical observation that the night sky is dark, when in a static infinite universe the night sky ought to be bright. ... Categories: Astronomers stubs | 1758 births | 1840 deaths | German astronomers | German physicists | Lists of asteroids ... Ole Rømer. ... Oliver Heaviside (May 18, 1850 – February 3, 1925) was a self-taught English engineer, mathematician and physicist who adapted complex numbers to the study of electrical circuits, developed techniques for applying Laplace transforms to the solution of differential equations, reformulated Maxwells field equations in terms of electric and magnetic... Olympus Mons Olympus Mons (Latin, Mount Olympus) is the tallest known mountain in our solar system, located on the planet Mars at approximately 18° N 226° E. Before space probes revealed its identity as a mountain, Olympus Mons was known to astronomers as the albedo feature, Nix Olympica (Snows of... Tomb of Omar Khayyám, Nishapur, Iran. ... A small region at the heart of Omega Centauri, containing some 50,000 stars (NASA/STScI) Omega Centauri or NGC 5139 is a globular cluster of stars orbiting our galaxy, the Milky Way. ... In physical cosmology, omniverse is a term used to differentiate a limited number of universes from all existent universes. ... One antenna from the One-Mile Telescope The One-Mile Telescope at the Mullard Radio Astronomy Observatory (MRAO) was completed by the Radio Astronomy Group of Cambridge University in 1964. ... Onsala Space Observatory (OSO) is the Swedish National Facility for Radio Astronomy located 45 km south of Gothenburg in Onsala. ... This image is an artists rendering of the Oort cloud and the Kuiper Belt. ... Jan Hendrik Oort (April 28, 1900 – November 5, 1992) was an internationally famous Dutch astronomer. ... The Ooty Radio Telescope near Ootacamund (Ooty) was set up by TIFR radio astronomers, in the picturesque Nilgiri Hills of South India in 1970. ... An open cluster is a group of up to a few thousand stars that were formed from the same giant molecular cloud, and are still loosely gravitationally bound to each other. ... Atmospheric pressure 0 kPa Ophelia (o-fee-lee-a) is a moon of Uranus. ... Ophiuchus (known as the serpent holder) is one of the 88 constellations, and was also one of the 48 listed by Ptolemy. ... Opposition is a term used in positional astronomy and astrology to indicate when one celestial body is on the opposite side of the sky when viewed from a particular place (usually the Earth). ... Optical astronomy encompasses a wide variety of observations via telescopes that are sensitive in the range of visible light. ... In telecommunication, the term optical axis has the following meanings: 1. ... This topic is about the astronomical phenomenon. ... Optical depth is a measure of transparency, and is defined as the fraction of radiation that is scattered between a point and the observer. ... This topic is about the astronomical phenomenon. ... This article is in need of attention. ... An optical telescope is a telescope which is used to gather, and focus light, for directly viewing a magnified image, making a photograph, etc. ... In astronomy, the optical window is that portion of the electromagnetic spectrum that passes through the atmosphere all the way to the ground. ... In physics, an orbit is the path that an object makes, around another object, whilst under the influence of a source of centripetal force, such as gravity. ... The elements of an orbit are the parameters needed to specify that orbit uniquely, given a model of two ideal masses obeying the Newtonian laws of motion and the inverse-square law of gravitational attraction. ... The orbital period is the time it takes a planet (or another object) to make one full orbit. ... The orbital plane of an object orbiting another is the geometrical plane in which the orbit is embedded. ... In celestial mechanics, orbital resonance occurs when two orbiting bodies have periods of revolution that are in a simple integer ratio so that they exert a regular gravitational influence on each other. ... Orbital revolution is the cyclical path taken by one object around another object (or point, line, etc. ... The orbital speed of a body, generally a planet, a natural satellite, an artificial satellite, or a multiple star, is the speed at which it orbits around the barycenter of a system, usually around a more massive body. ... OAO-3 in the clean room The Orbiting Astronomical Observatory (OAO) satellites were a series of four space observatories launched by NASA between 1966 and 1972, which provided the first high-quality observations of many objects in ultraviolet light. ... Pre-Cambrian stromatolites in the Siyeh Formation, Glacier National Park. ... The first serious attempts at naming the features of the Earths moon as seen through a telescope were made by Michel Florent van Langren in 1645. ... Orion, a constellation often referred to as The Hunter, is a prominent constellation, perhaps the best-known in the sky. ... The entire Orion Nebula in visible light Optical images reveal clouds of gas and dust in the Orion Nebula; an infrared image (right) reveals the new stars shining within. ... An orrery is a mechanical device that illustrates the relative positions and motions of the planets and moons in the solar system in heliocentric model. ... The oscillatory universe is the hypothesis, attributable to Richard Tolman, that the universe undergoes an infinite series of oscillations, each beginning with a big bang and ending with a big crunch. ... The Osservatorio Astrofisico di Arcetri is an astronomical observatory located in Arcetri in the outskirts of Florence, Italy. ... Montes Rook is a ring-shaped mountain range that lies along the western limb of the Moon, crossing over to the far side. ... Layers of Atmosphere - not to scale (NOAA) Outer space, also called just space, refers to the relatively empty regions of the Universe outside the atmospheres of celestial bodies. ... The Overwhelmingly Large Telescope (OWL) is a conceptual design by the European Southern Observatory organization for a telescope which is intended to have a single aperture of 100 meters in diameter. ... The Owens Valley Radio Observatory (OVRO) is a radio observatory located near Bishop, California, approximately 250 miles north of Los Angeles on the east side of the Sierra Nevada. ... The Owl Nebula (also known as Messier Object 97 or NGC 3587) is a planetary nebula in the constellation Ursa Major. ...

P

The p process was believed to be a proton capture process which occurrs during supernovae explosions. ... P-type asteroids have low albedo and a featureless reddish spectrum. ... Paaliaq (paw-lee-aak) is a natural satellite of Saturn. ... The Palermo Technical Impact Hazard Scale is a logarithmic scale used by astronomers to rate the potential hazard of impact of a near-earth object. ... A palimpsest is a manuscript page, scroll, or book that has been written on, scraped off, and used again. ... Johann Palisa (December 6, 1848 – May 2, 1925) was an Austrian astronomer, born in Troppau in Austrian Silesia (now in the Czech Republic). ... A pallasite is an iron meteorite, related to a mesosiderite. ... Discovery image of Pallene Pallene (pa-lee-nee, Greek Παλλήνη) is a natural satellite of Saturn. ... Palomar Observatory is a privately-owned observatory located in San Diego County, California, 90 miles (145 km) southeast of Mount Wilson Observatory, on Palomar Mountain. ... The National Geographic Society - Palomar Observatory Sky Survey (NGS-POSS) is a major photographic survey of the night sky completed at Palomar Observatory in 1958. ... The Palomar Testbed Interferometer is a near-IR, long-baseline stellar interferometer located at Palomar Observatory in north San Diego County. ... Atmosphere none Pan (pan, Greek Πάν) is a moon of Saturn, named after the god Pan. ... Pandora (pan-dor-a, Greek Πανδώρα) is a moon of Saturn. ... Panspermia is the hypothesis that the seeds of life are ubiquitous (Omnipresent or every where at once) in the Universe, that they may have delivered life to Earth, and that they may deliver or have delivered life to other habitable bodies; also the process of such delivery. ... A parabolic reflector (also known as a parabolic dish or a parabolic mirror) is a reflective device formed in the shape of a paraboloid of revolution. ... A parabolic reflector (also known as a parabolic dish or a parabolic mirror) is a reflective device formed in the shape of a paraboloid of revolution. ... Parallax (Greek: παραλλαγή (parallagé) = alteration) is the change of angular position of two stationary points relative to each other as seen by an observer, due to the motion of an observer. ... // The many-worlds interpretation (or MWI) is an interpretation of quantum mechanics that rejects the non-deterministic and irreversible wavefunction collapse associated with measurement in the Copenhagen interpretation in favor of a description in terms of quantum entanglement and reversible time evolution of states. ... The European Southern Observatory (ESO) is an international astronomical organisation, composed and supported by ten countries from the European Union plus Switzerland and was created in 1962. ... gros pd]], enfoire at Nançay. ... The big dish The Parkes Observatory is a radio telescope observatory, 20 kilometres north of the town of Parkes, New South Wales, Australia. ... The parsec (symbol pc) is a unit of length used in astronomy. ... William Parsons, 3rd Earl of Rosse, usually known as Lord Rosse, was a 19th-century Irish astronomer. ... The particle horizon in cosmology is the distance from which particles (of positive mass or of zero mass) can have travelled to the observer in the age of the Universe. ... Pasiphaë (IPA: , pa-sif-a-ee, Greek Πασιφάη) is a moon of Jupiter. ... The Pasiphaë group is made up of moons of Jupiter which share similar orbits. ... Prof. ... A number of major astronomical facilities are located at the Paul Wild Observatory near Narrabri, Australia, including: The Australia Telescope Compact Array radio telescope The Narrabri Stellar Intensity Interferometer (now decommissioned) The Sydney University Stellar Interferometer (see http://www. ... The Pauli exclusion principle is a quantum mechanical principle formulated by Wolfgang Pauli in 1925, which states that no two identical fermions may occupy the same quantum state. ... PENIS, being Latin for your small cock, is a southern constellation. ... Cecilia Payne-Gaposchkin (May 10, 1900 – December 7, 1979) was a British-American astronomer. ... PBS re-directs here; for alternate uses see PBS (disambiguation) PBS logo The Public Broadcasting Service (PBS) is a non-profit public broadcasting television service with 349 member TV stations in the United States. ... Pegasus is a northern constellation, named after the mythological Pegasus. ... Peirce is a small lunar crater that lies in the western part of Mare Crisium. ... Sir Roger Penrose, OM, FRS (born 8 August 1931) is an English mathematical physicist and Emeritus Rouse Ball Professor of Mathematics at the University of Oxford. ... Umbra & penumbra The penumbra (Latin for mid-shadow) is the portion of a shadow that results from the source of illumination being only partially blocked. ... This article is about several astronomical terms (apogee & perigee, aphelion & perihelion, generic equivalents based on apsis, and related but rarer terms. ... This article is about several astronomical terms (apogee & perigee, aphelion & perihelion, generic equivalents based on apsis, and related but rarer terms. ... This article is about several astronomical terms (apogee & perigee, aphelion & perihelion, generic equivalents based on apsis, and related but rarer terms. ... This article is about several astronomical terms (apogee & perigee, aphelion & perihelion, generic equivalents based on apsis, and related but rarer terms. ... Charles Dillon Perrine (July 28, 1867 – June 21, 1951) was an American-Argentine astronomer. ... The Perseids are a prolific meteor shower associated with the comet Swift-Tuttle. ... Perseus is a northern constellation, named after the Greek hero who slew the monster Medusa. ... The Perseus Cluster (Abell 426) is a cluster of galaxies in the constellation Perseus. ... Phecda is one of the stars of the Big Dipper. ... Newtons own copy of his Principia, with hand written corrections for the second edition. ... Phobos (IPA , Greek Φόβος: Fright), is the larger and innermost of Mars two moons, and is named after Phobos, son of Ares (Mars) from Greek Mythology. ... Categories: Astronomy stubs | Modern constellations | Constellations ... Photographic plates were one of the earliest forms of photographic film, in which a light-sensitive emulsion of silver salts was applied to a glass plate. ... Photometry is a technique of astronomy concerned with measuring the flux, or intensity of an astronomical objects electromagnetic radiation. ... The photosphere of an astronomical object is the region at which the optical depth becomes one for a photon of wavelength equal to 5000 angstroms. ... Cosmology, as a branch of astrophysics, is the study of the large-scale structure of the universe and is concerned with fundamental questions about its formation and evolution. ... Charles Piazzi Smyth (January 3, 1819 – February 21, 1900), was Astronomer Royal of Scotland from 1846 to 1888. ... Giuseppe Piazzi - Wikipedia /**/ @import /skins-1. ... Picard is a lunar impact crater that lies in the western part of the Mare Crisium. ... Edward Charles Pickering (July 19, 1846 – February 3, 1919) was an American astronomer and physicist, brother of William Henry Pickering. ... William Henry Pickering (February 15, 1858 – January 17, 1938) was an American astronomer, brother of Edward Charles Pickering. ... Pictor, being Latin for easel, is one of the minor southern (declination -50 to -60) constellations. ... Pierre Auger Observatory is an international cosmic ray observatory designed to detect ultra high energy cosmic rays -- Oh-My-God particles. ... Pierre François André Méchain (August 16, 1744 – September 20, 1804) was a French astronomer. ... Pieter Dirkszoon Keyser (1540-1596) was a Dutch navigator. ... The Pinwheel Galaxy (also known as Messier Object 101, or NGC 5457) is a spiral galaxy in the constellation Ursa Major. ... Pioneer 10 in the final stage of construction Launch of Pioneer 10 Pioneer 10 (also called Pioneer F) was the first spacecraft to travel through the asteroid belt, and was the first spacecraft to make direct observations of Jupiter. ... Pioneer 11 at Saturn (artists impression) Pioneer 11 was the second mission to investigate Jupiter and the outer solar system and the first to explore the planet Saturn and its main rings. ... Pisces (Latin for fish (plural), symbol , Unicode ♓) is a zodiac constellation which lies between Aquarius to the west and Aries to the east. ... Piscis Austrinus or Piscis Australis (both of which are Latin for Southern Fish) was one of the 48 constellations listed by Ptolemy, and is also one of the 88 modern constellations. ... Aerial view of the Piwnice astronomical observatory 32-m radiotelescope Piwnice radio observatory is located at Piwnice, 15 km north of Torun, Poland. ... WMAP image, unrelated to Planck The Planck Surveyor is the third Medium-Sized Mission (M3) of ESAs Horizon 2000 Scientific Programme. ... Planck units, first proposed by Max Planck in 1899 and sometimes called natural units, are a system of units for measuring time, length, mass, electric charge, and temperature. ... Black body spectrum as a function of wavelength In physics, the spectral intensity of electromagnetic radiation from a black body at temperature T is given by the Plancks law of black body radiation: where: I(ν) is the amount of energy per unit time per unit surface area per unit... Max Planck This article is about Planck, the German physicist. ... A planet is generally considered to be a relatively large mass of accreted matter in orbit around a star that is not a star itself. ... Planet X was a large hypothetical planet orbiting beyond the orbit of Neptune. ... A planetarium is a theater built primarily for presenting educational and entertaining shows about astronomy and the night sky, or for training in celestial navigation. ... ... NGC 6543, the Cats Eye Nebula A planetary nebula is an astronomical object consisting of a glowing shell of gas and plasma formed by certain types of stars at the end of their lives. ... Planetary nomenclature, like terrestrial nomenclature, is used to uniquely identify a feature on the surface of a planet or natural satellite so that the feature can be easily located, described, and discussed. ... Two bodies with a slight difference in mass orbiting around a common barycenter. ... Planetary phase is the term used to describe the appearance of the illuminated section of a planet. ... A planetary ring is a ring of dust and other small particles orbiting around a planet in a flat disc-shaped region. ... Planetary science, also known as planetology or planetary astronomy, is the science of planets, or planetary systems, and the solar system. ... An artists concept of a protoplanetary disk. ... ÈàÌàìòòIn cosmogony, planetesimals are objects thought to exist within solar nebulae. ... Planetoid (meaning planet-like) is an old synonym of asteroid. ... Planetary science, also known as planetology or planetary astronomy, is the science of planets and the solar system, and incorporates an interdisciplinary approach drawing from diverse sciences. ... Planisphaerium, from Wormed Planisphærium is the 2003 debut album from the brutal death metal band Wormed. ... Plasma Universe and plasma cosmology. ... The Plateau de Bure Interferometer is a six-antenna interferometer on the Plateau de Bure (2550m) in France, operated by the Institut de Radio Astronomie Millimétrique. ... Plato Plato (Greek: Πλάτων, Plátōn) (c. ... The Pleiades are an open cluster dominated by hot blue stars surrounded by reflection nebulosity The Pleiades (also known as M45 or the Seven Sisters) is an open cluster in the constellation of Taurus. ... In astronomy, a plutino is a trans-Neptunian object that has a 3:2 orbital resonance with Neptune. ... Atmospheric characteristics Atmospheric pressure 0. ... Norman Robert Pogson (March 23, 1829 – June 23, 1891) was a British astronomer. ... In physics and mathematics, the Poincaré group is the group of isometries of Minkowski spacetime. ... Henri Poincaré, photograph from the frontispiece of the 1913 edition of Last Thoughts Jules Henri Poincaré (April 29, 1854 – July 17, 1912), generally known as Henri Poincaré, was one of Frances greatest mathematicians and theoretical physicists, and a philosopher of science. ... Simeon Poisson. ... Aurora borealis Polar aurorae are optical phenomena characterized by colorful displays of light in the night sky. ... This article describes some of the common coordinate systems that appear in elementary mathematics. ... This article describes some of the common coordinate systems that appear in elementary mathematics. ... Polar distance (PD) is an astronomical term associated with the celestial equatorial coordinate system Σ(α, δ) and it is an angular distance of a celestial object on its meridian measured from the celestial pole, similar as declination (dec, δ) is measured from the celestial equator: PD = 90° ± δ Polar... Polarimetry is the measurement of the polarisation of light; a polarimeter is the scientific instrument used to make these measurements. ... Polaris (α UMi / α Ursae Minoris / Alpha Ursae Minoris) is the brightest star in the constellation Ursa Minor. ... In electrodynamics, polarization (also spelled polarisation) is a property of waves, such as light and other electromagnetic radiation. ... This article treats polarization in electrodynamics. ... In Greek mythology, Pollux or Polydeuces was one of the twin sons of Zeus, see Castor and Pollux Pollux is a bright star in the constellation Gemini. ... Atmosphere none Polydeuces (pol-ee-dew-seez, Greek Πολυδεύκης) is a natural satellite of Saturn that was discovered on images taken on October 21, 2004 by the Cassini imaging team, led by Carolyn C. Porco et al, and given the temporary designation S/2004 S 5. ... John Pond (c. ... Jean-Louis Pons (December 24, 1761 – October 14, 1831) was a French astronomer. ... Stars can be grouped into two general types called Population I and Population II. The criteria for classification include space velocity, location in the galaxy, age, chemical composition, and differences in distribution on the Hertzsprung-Russell diagram. ... Gamma Virginis (γ Vir / γ Virginis) is a star in the constellation Virgo. ... Atmospheric pressure 0 kPa Portia (por-sha) is a moon of Uranus. ... The bust of Posidonius as an older man depects his character as a Stoic philosopher. ... Positional astronomy is the study of the positions of celestial objects. ... Herman Potočnik (pseudonym Hermann Noordung) (December 12, 1892 - August 27, 1929) was a Slovene rocket engineer and pioneer of cosmonautics (astronautics). ... The Pre-Nectarian Period of the lunar geologic timescale runs from 4550 million years ago (the time of the initial formation of the Moon) to 3920 million years ago, when the Nectaris Basin was formed by a large impact. ... Precession refers to a change in the direction of the axis of a rotating object. ... Joseph Priestley is often credited for the discovery of oxygen. ... A primary mirror is a form of distributed data management on the Internet. ... Location of the Prime Meridian Prime Meridian in Greenwich The Prime Meridian is the meridian (line of longitude) passing through the Royal Greenwich Observatory, Greenwich, England; it is the meridian at which longitude is 0 degrees. ... A primordial black hole is a hypothetical type of black hole that is formed not by the gravitational collapse of a star but by the extreme densities of matter present during early universe. ... Note: The principle of relativity should not be confused with the Theory of relativity. ... If a shaft of light entering a prism is sufficiently small such that the coloured edges meet, a spectrum results In optics, a prism is a device used to refract light, reflect it or break it up (to disperse it) into its constituent spectral colours (colours of the rainbow). ... The Ocean of Storms of the Moon. ... Procyon (α CMi / α Canis Minoris / Alpha Canis Minoris) is the brightest star in the constellation Canis Minor and the eighth brightest star in the nighttime sky. ... This article is about the star. ... This article is about the star. ... Prograde motion is the rotational or orbital motion of a body in a direction similar to that of other bodies within a given system, and is sometimes called direct motion. ... This article is about retrograde motion. ... Prometheus (proe-mee-thee-us, Greek Προμηθέας) is a moon of Saturn. ... This page alphabetically lists the first thousand asteroids to be numbered, which are mostly in the main belt. ... The proper motion of a star is the motion of the position of the star in the sky (the change in direction in which we see it, as opposed to the radial velocity) after eliminating the improper motions of the stars, which affect their measured coordinates but are not real... The angular diameter distance is a distance measure used in astronomy. ... Proper time is time as measured by the clock for an observer who is traveling through spacetime. ... A protoplanetary disc (also protoplanetary disk, proplyd) is an accretion disc surrounding a T Tauri star. ... Atmospheric pressure 0 kPa Prospero (pros-pur-oe) is a relatively small natural satellite of the planet Uranus named after the sorcerer in William Shakespeares play The Tempest. ... Atmospheric pressure 0 kPa Proteus (proe-tee-us, Greek Πρωτέας) is one of Neptunes moons. ... The protostar period is the period in the evolution of a star after the cloud of hydrogen, helium and dust has started contraction and before the star has reached the main sequence on the Hertzsprung-Russell diagram. ... The proton-proton chain reaction is one of two fusion reactions by which stars convert hydrogen to helium, the other being the CNO cycle. ... A protoplanetary disc (also protoplanetary disk, proplyd) is an accretion disc surrounding a T Tauri star. ... A protoplanetary disc (also protoplanetary disk, proplyd) is an accretion disc surrounding a T Tauri star. ... Protostar is a period after clouds of hydrogen, helium and dust begin to contract and before the a star reaches the main sequence. ... The provisional designation of comets and asteroids are similar to each other: they both follow a pattern set in 1925 by the Minor Planet Center of the IAU. Historical designations At first, astronomers strove to assign symbols to the minor planets: 1 Ceres a stylized sickle 2 Pallas a lozenge... It has been suggested that this article or section be merged into Alpha Ccentauri. ... PSR 1257+12 (also catalogued as PSR B1257+12,PSR 1300+1240 and PSR J1300+1240) is a pulsar located 2630 light years from Earth. ... PSR B1620-26 is also called PSR J1623-2631 (or or ) // System Configuration PSR B1620-26 is a pulsar in the globular cluster Messier 4 (or M4: see Messier object), about 5,600 light years from Earth in the constellation Scorpius. ... An artists impression of the view from near the planet PSR B1620-26c is a planet orbiting the pulsar PSR B1620-26 in the globular cluster Messier 4, about 12,400 light years from Earth in the constellation of Scorpius. ... In astronomy, and in particular the study of pulsars, PSR J1748-2446ad is the fastest known spinning pulsar, at 716 Hz, the period being 0. ... Mediaeval drawing of the Ptolemaic system. ... Claudius Ptolemaeus (Greek: ; ca. ... Open star cluster Messier 7 The Ptolemy Cluster (also known as Messier Object 7 or NGC 6475) is an open cluster in the constellation Scorpius. ... Atmospheric pressure 0 kPa Puck (puk) is a moon of Uranus. ... Composite Optical/X-ray image of the Crab Nebula pulsar, showing surrounding nebular gases stirred by the pulsars magnetic field and radiation. ... The human eye The pupil is the central transparent area (showing as black). ... Puppis (Latin for poop deck) is a southern constellation. ... Pythagoras (approximately 580 BC–500 BC, Greek: Πυθαγόρας) was an Ionian (Greek) mathematician and philosopher, founder of the mysterious religious and scientific society called Pythagoreans, and is known best for the Pythagorean theorem which bears his name. ... Categories: Astronomy stubs | Modern constellations | Constellations | Pyxis constellation | Argo Navis constellation ...

Q

Q-type asteroids are inner-belt asteroids with a strong, broad 1 micrometre olivine and pyroxene feature, and a spectral slope that indiciates the presence of metal. ... Look up Quadrant on Wiktionary, the free dictionary Quadrant can mean: HMS Quadrant (G11), a WW-II British/Australian warship. ... The quadrivium comprised the four subjects taught in medieval universities after the trivium. ... Quantum gravity is the field of theoretical physics attempting to unify the theory of quantum mechanics, which describes three of the fundamental forces of nature, with general relativity, the theory of the fourth fundamental force: gravity. ... This article is about the trans-Neptunian object. ... A quark-gluon plasma (QGP) is a phase of quantum chromodynamics (QCD) which exists at extremely high temperature and density. ... This view, taken with infrared light, is a false-color image of a quasar-starburst tandem with the most luminous starburst ever seen in such a combination. ... Quasars, Redshifts and Controversies is a 1987 book by Halton Arp, an astronomer famous for his work on anomalous redshifts. ... Didier Queloz, born 23 February 1966, is a Geneva-based astronomer with a prolific record in finding extrasolar planets. ... Lambert Adolphe Jacques Quételet (February 22, 1796 - 1874) was a Belgian astronomer, mathematician, statistician and sociologist. ... The word quintessence is used in different fields: In physics, quintessence is a hypothetical form of energy postulated to exist as a possible explanation of observations of an accelerating universe. ... In physics, quintessence is a hypothetical form of dark energy postulated as an explanation of observations of an accelerating universe. ...

R

The R process (R for rapid) is a neutron capture process for radioactive elements which occurs in high neutron density, high temperature conditions. ... R-type asteroids are moderately bright, inner-belt asteroids that are spectrally intermediate between the V and A-type asteroids. ... Paul Butler is an astronomer who searches for extrasolar planets. ... David Lincoln Rabinowitz (born 1960) is a researcher at Yale University studying the Kuiper belt and the outer solar system. ... Radial velocity is the velocity of an object in the direction of the line of sight. ... The radian (symbol: rad, or a superscript c ( half circle)) is the SI unit of plane angle. ... Categories: Planetology | Astronomy stubs ... Radiation pressure is the pressure exerted upon any surface exposed to electromagnetic radiation. ... Microwave image of 3C353 galaxy at 8. ... An active galaxy is a galaxy where a significant fraction of the energy output is not emitted by the normal components of a galaxy: stars, dust and interstellar gas. ... Radio halos are large-scale areas of radio emission found in clusters of galaxies. ... Radio stars are stars that produce by means of chemical and electrical discharges, emissions of various radio frequencies, whether constant or pulsed. ... The 64 metre radio telescope at Parkes Observatory In contrast to an ordinary telescope, which produces visible light images, a radio telescope sees radio waves emitted by radio sources, typically by means of a large parabolic (dish) antenna, or arrays of them. ... This page is a candidate to be moved to Wiktionary. ... The rare Earth hypothesis is a response to the Fermi paradox which explains why we might expect a planet such as Earth to be very rare. ... Ras Algethi (Arabic Rasalgethi from Ra`s al-Jathi a Head of the kneeling one) (α 1 Herculis | 64 Herculis) is a double star system with a primary massive red giant star and a closer companion. ... Zelenchukskaya (Russian: Зеленчукская) is the Caucasus Mountains site of the Special Astrophysical Observatory (Специальная Астрофизическая Обсерватория) of the Russian Academy of Sciences, St Petersburg. ... Rayleigh scattering causing a reddened sky at sunset Rayleigh scattering (named after Lord Rayleigh) is the scattering of light, or other electromagnetic radiation, by particles much smaller than the wavelength of the light. ... Grote Reber (December 22, 1911 – December 20, 2002) was one of the pioneers of radio astronomy. ... The Red Clump is a region on the Hertzsprung-Russell diagram occupied primarily by metal-rich red giant stars. ... This article describes the British science fiction comedy television series. ... This article is about red dwarfs, the type of star. ... According to the Hertzsprung-Russell diagram, a red giant is a large non-main sequence star of stellar classification K or M; so-named because of the reddish appearance of the cooler giant stars. ... Redshift of spectral lines in the optical spectrum of a supercluster of distant galaxies (right), as compared to that of the Sun (left). ... The Right Honourable Martin John Rees, Baron Rees of Ludlow, FRS (born 23 June 1942) is a professor of astronomy. ... A frame of reference in physics is a set of axes which enable an observer to measure the aspect, position and motion of all points in a system relative to the reference frame. ... Ritchey 24 reflecting telescope A reflecting telescope (reflector) is an optical telescope which uses mirrors to reflect light, rather than lenses to pass light. ... In astronomy, reflection nebulae are clouds of dust which are simply reflecting the light of a nearby star or stars. ... A refracting telescope: 1 - tube; 2 - eyepiece; 3 - mountingl; 4 - tripod; 5 - counterweights A refracting or refractor telescope is a type of optical telescope that refracts or bends light at each end using lenses. ... Johannes Müller von Königsberg (June 6, 1436 – July 6, 1476), known by his Latin pseudonym Regiomontanus, was an important German mathematician, astronomer and astrologer. ... Regolith (Greek: blanket rock) is a layer of loose, heterogeneous material covering solid rock. ... Regulus (α Leo / α Leonis / Alpha Leonis) is the brightest star in the constellation Leo and one of the brightest stars in the nighttime sky. ... Erasmus Reinhold (October 22, 1511 – February 19, 1553) was a German astronomer and mathematician. ... Harold J. Reitsema is an astronomer who discovered Larissa, which is the fifth of Neptunes known moons. ... Relativistic Jet. ... The Research Consortium on Nearby Stars (RECONS) is a project to investigate the stars nearest to the Solar System - those within 10 parsecs (32. ... Resolving power is the ability of a microscope or telescope to measure the angular separation of images that are close together. ... Reticulum (Latin for reticle), is one of the minor southern (declination -60 degrees) constellations. ... This article is about retrograde motion. ... Prograde motion is the rotational or orbital motion of a body in a direction similar to that of other bodies within a given system, and is sometimes called direct motion. ... This article is about retrograde motion. ... The Revised Julian calendar is a calendar that was considered for adoption by the Eastern Orthodox churches at a synod in Istanbul in May 1923. ... Alastair Reynolds is a Welsh science fiction author. ... Atmosphere none Rhea (ree-a, Greek ‘Ρέα) is the second largest moon of Saturn and was discovered in 1672 by Giovanni Domenico Cassini. ... Georg Joachim von Lauchen Rheticus was born in 1514 at Feldkirch, Austria and died in 1574 at Kosice, Hungary. ... Rho Coronae Borealis (ρ CrB / ρ Coronae Borealis) is a 6th magnitude star in the constellation of Corona Borealis. ... Rhyolite Rhyolite is an igneous, volcanic (extrusive) rock, of felsic composition, with aphanitic to porphyritic texture. ... In mathematics, Riemannian geometry has at least two meanings, one of which is described in this article and another also called elliptic geometry. ... Rigel (pronounced ) (β Orionis) is the brightest star in the constellation Orion and the seventh brightest star in the sky, with visual magnitude 0. ... Right ascension (RA; symbol α: Greek letter alpha) is the astronomical term for one of the two coordinates of a point on the celestial sphere when using the equatorial coordinate system. ... Rijl al Awwa (μ Vir / μ Virginis / mu Virginis) is a star in the constellation Virgo. ... Rima Sirsalis is a lunar rille, an open lava channel or a collapsed lava tube on the Moon. ... M57, The Ring Nebula Planetary Nebula M57 (also known as the Ring Nebula, NGC 6720 or Messier Object 57) is located in the constellation Lyra. ... A ring current is an electric current carried by charged particles trapped in a planets magnetosphere. ... A ring galaxy is a galaxy with a ring-like appearance. ... Saturns rings; the major rings are labelled This is a list of the 15 named rings of Saturn, and the gaps between them. ... Ritchey 24 reflecting Telescope George Willis Ritchey (December 31, 1864 – November 4, 1945) was an American optician and telescope maker and astronomer (educated as a furniture maker) born at Tuppers Plains, Ohio. ... The Ritchey-Chrétien telescope or RCT is a specialized Cassegrain telescope with a hyperbolic primary and secondary mirror. ... Robert Burnham, Jr. ... Robert G. Harrington was an American astronomer who worked at Palomar Observatory. ... A portrait, claimed by historian Lisa Jardine to be of Robert Hooke Robert Hooke, FRS (July 18, 1635 - March 3, 1703) was an English polymath who played an important role in the scientific revolution, through both experimental and theoretical work. ... J. Robert Oppenheimer, father of the atomic bomb, served as the first director of Los Alamos National Laboratory, beginning in 1943. ... Robert Woodrow Wilson (born January 10, 1936) is an American physicist. ... A robotic telescope is an astronomical telescope and detector system that makes observations without the intervention of a human. ... The Roche limit is the distance within which a celestial body held together only by its own gravity will disintegrate due to a second celestial bodys tidal forces exceeding the first bodys gravitational self-attraction. ... The Roche lobe is the region of space around a star in a binary system within which orbiting material is gravitationally bound to that star. ... Édouard Albert Roche (1820-1883) was a French scientist. ... A Redstone rocket, part of the Mercury program A rocket is a vehicle, missile or aircraft which obtains thrust by the reaction to the ejection of fast moving exhaust gas from within a rocket engine. ... The seeing statistics for Roque de los Muchachos Observatory make it the third best location for optical and infrared astronomy after Dome C, Antarctica and Mauna Kea Observatory, Hawaii. ... Atmospheric pressure 0 kPa Rosalind (roz-a-lind) is a moon of Uranus. ... ROSAT ROSAT (short for Röntgensatellit) was a German X-ray satellite telescope. ... Embedded in the center of the Rosette Nebula is an open cluster. ... Ross 128 is a red dwarf star approximately 3. ... Ross 154 is a red dwarf star approximately 3. ... Ross 248 is a gimp approximately 3. ... The Rossi X-ray Timing Explorer (RXTE) satellite observes the fast-moving, high-energy worlds of black holes, neutron stars, X-ray pulsars and bursts of X-rays that light up the sky and then disappear forever. ... In astronomy, a rotation period is the time an astronomical object takes to complete one revolution around its rotation axis. ... The Royal Astronomical Society (RAS) began as the Astronomical Society of London in 1820 to support astronomical research (mainly carried on at the time by gentleman astronomers rather than professionals). ... Royal Observatory, Greenwich The original site of the Royal Greenwich Observatory (RGO), which was built as a workplace for the Astronomer Royal, was on a hill in Greenwich Park in Greenwich, London, overlooking the River Thames. ... The Royal Observatory, Edinburgh (ROE) is located on Blackford Hill in the south of the city of Edinburgh. ... RR Lyrae is a variable star in the Lyra constellation. ... Hertzsprung-Russell diagram adapted from Powell. ... Vera (Cooper) Rubin (born 23 July 1928) is an astronomer who has done pioneering work on galaxy rotation rates. ... Olaus Rudbeckius, senior or (1630-1702), Swedish scientist and writer, professor of medicine at Uppsala University and for several periods rector magnificus (headmaster) of the same university. ... Henry Norris Russell (October 25, 1877 – February 18, 1957) was a US astronomer who, along with Ejnar Hertzsprung, developed the Hertzsprung-Russell diagram (1910). ... The Ryle Telescope was re-arranged to form the long baseline array of AMI after this photo was taken. ... Sir Martin Ryle (September 27, 1918 – October 14, 1984) was a British radio astronomer who developed revolutionary radio telescope systems (see e. ... Ole Rømer. ...

S

The S process (S for slow) is a neutron capture process in the decay of radioactive elements that occurs in lower neutron density, lower temperature conditions. ... Approximately 17% of all known asteroids are of an S-type (for stony) composition. ... Atmospheric pressure 0 kPa S/1986 U 10 is an unnamed moon of Uranus. ... Atmospheric pressure 0 kPa S/2001 U 2 is a natural satellite of Uranus. ... Atmospheric pressure 0 kPa S/2001 U 3 is a natural satellite of Uranus. ... S/2002 N 1 is a natural satellite of Neptune. ... S/2002 N 2 is a natural satellite of Neptune. ... S/2002 N 3 is a natural satellite of Neptune. ... S/2002 N 4 is a natural satellite of Neptune. ... S/2003 J 12 is a natural satellite of Jupiter. ... S/2003 J 2 is a natural satellite of Jupiter. ... S/2003 N 1 is a natural satellite of Neptune. ... Atmospheric pressure 0 kPa S/2003 U 1 is a natural satellite of Uranus. ... Atmospheric pressure 0 kPa S/2003 U 2 is a natural satellite of Uranus. ... Atmospheric pressure 0 kPa S/2003 U 3 is a natural satellite of Uranus. ... S/2004 S 10 is a natural satellite of Saturn. ... S/2004 S 11 is a natural satellite of Saturn. ... S/2004 S 12 is a natural satellite of Saturn. ... S/2004 S 13 is a natural satellite of Saturn. ... S/2004 S 14 is a natural satellite of Saturn. ... S/2004 S 15 is a natural satellite of Saturn. ... S/2004 S 16 is a natural satellite of Saturn. ... S/2004 S 17 is a natural satellite of Saturn. ... S/2004 S 18 is a natural satellite of Saturn. ... S/2004 S 3 is the provisional designation of an unconfirmed moon of Saturn. ... S/2004 S 4 is the designation of an unconfirmed moon of Saturn announced by the Cassini Imaging Team on September 9, 2004. ... S/2004 S 6 is the provisional designation of a natural satellite of Saturn that was discovered in 2004 (on October 28 images) by the Cassini probe team, led by Carolyn C. Porco et al. ... S/2004 S 7 is a natural satellite of Saturn. ... S/2004 S 8 is a natural satellite of Saturn. ... S/2004 S 9 is a natural satellite of Saturn. ... Sir Edward Sabine (October 14, 1788 – May 26, 1883) was an Irish astronomer, scientist, ornithologist and explorer. ... Dr. Carl Edward Sagan (November 9, 1934 – December 20, 1996) was an American astronomer, astrobiologist, and highly successful science popularizer. ... Sagitta, being Latin for Arrow, is the third-smallest of all constellations (only Equuleus and Crux are smaller). ... Sagittarius (Latin for Archer, symbol , Unicode ♐) is a constellation of the zodiac, commonly depicted as a centaur drawing a bow. ... Sagittarius A (or Sgr A) is a complex radio source at the center of our galaxy, the Milky Way. ... The Sagittarius Dwarf Elliptical Galaxy (Sag DEG) is a satellite galaxy of the Milky Way Galaxy. ... Saiph, or κ Orionis (kappa Orionis) is the sixth-brightest star in the constellation of Orion. ... The Samuel Oschin telescope is a 48-inch (1. ... Allan Rex Sandage (Born June 18, 1926) is an American astronomer. ... A Saros cycle is a period of 6585 + 1/3 days (approximately 18 years 10 days and 8 hours) which can be used to predict eclipses of the sun and the moon. ... A satellite is any object that orbits another object (which is known as its primary). ... Atmospheric characteristics Atmospheric pressure 140 kPa Hydrogen >93% Helium >5% Methane 0. ... NGC 7009, the Saturn Nebula. ... The Saturnian System (photographic montage) Saturn Rings and Satellites. ... Sir Henry Savile (1549 – February 19, 1622), warden of Merton College, Oxford, and provost of Eton, was the son of Henry Savile of Bradley, near Halifax, in Yorkshire, a member of an old county family, the Saviles of Methley, and of his wife Elizabeth, daughter of Robert Ramsden. ... The introduction to this article provides insufficient context for those unfamiliar with the subject matter. ... The scattered disc (or scattered disk) is a distant region of our solar system, thinly populated by icy planetoids known as scattered disk objects (SDOs), a subset of the broader family of trans-Neptunian objects (TNOs). ... Christoph Scheiner (July 25, 1573 or 1575 – June 18, 1650) was a German astronomer and Jesuit. ... 2m Schmidt Camera (Alfred-Jensch-Telescope Tautenburg, Thuringia, Germany A Schmidt camera is an astronomical camera designed to provide wide fields of view with limited aberrations. ... A Schmidt corrector plate, invented by Bernhard Schmidt in 1931, is a lens used to correct spherical aberration in a reflecting telescope that uses a spherical primary mirror. ... Bernhard Schmidt (March 30, 1879–December 1, 1935) was an Estonian-born optician who lived in Germany. ... Maarten Schmidt (born December 28, 1929) is a Dutch astronomer who measured the distances of astronomical objects called quasars. ... Schmidt-Cassegrain The Schmidt-Cassegrain, invented by Bernhard Schmidt, is similar to the Cassegrain. ... A Schmidt-Cassegrain Telescope, invented by Bernhard Schmidt, is a catadioptric telescope. ... Samuel Heinrich Schwabe (October 25, 1789–April 11, 1875) was a German astronomer. ... Samuel Heinrich Schwabe (October 25, 1789–April 11, 1875) was a German astronomer. ... It has been suggested that Deriving the Schwarzschild solution be merged into this article or section. ... The Schwarzschild radius (sometimes inappropriately referred to as the gravitational radius[1]) is a characteristic radius associated with every mass. ... Karl Schwarzschild (October 9, 1873 - May 11, 1916) was a noted German Jewish physicist and astronomer, father of astrophysicist Martin Schwarzschild. ... 73P/Schwassmann-Wachmann, also known as Schwassmann-Wachmann 3, is a periodic comet in our solar system which is in the process of disintegrating. ... Science is the journal of the American Association for the Advancement of Science (AAAS). ... Scintillation or twinkling are generic terms for rapid variations in apparent brightness or color of a distant luminous object viewed through the atmosphere. ... Scorpius (Latin for scorpion, symbol , Unicode ♏) is one of the constellations of the zodiac. ... Categories: Astronomy stubs | Modern constellations | Constellations | Sculptor constellation ... The Sculptor group of galaxies (also known as the South Polar group of galaxies, the South Polar group, or simply the Sculptor group) is a physical group and a galaxy cluster. ... Scutum (Latin for shield) is a small constellation. ... The second superstring revolution refers to the intense wave of breakthroughs in string theory that took place approximately between 1994 and 1997. ... A second of arc or arcsecond is a unit of angular measurement which comprises one-sixtieth of an arcminute, or 1/3600 of a degree of arc or 1/1296000 ≈ 7. ... A secondary mirror (or secondary) is a second light gathering and focusing surface in a reflector telescope. ... The word seeing can mean more than one thing: In common usage, the word means visual perception In astronomy, seeing is a technical term related to the blurring effects of air turbulence in the atmosphere In the occult seeing refers to the sight or the ability to see auras or... The semi-major axis of an ellipse In geometry, the term semi-major axis (also semimajor axis) is used to describe the dimensions of ellipses and hyperbolas. ... Semidetached binary stars are the ones where one of the components fills its Roche lobe and the other does not. ... In geometry, the semi-major axis (also semimajor axis) a applies to ellipses and hyperbolas. ... Semiregular variable stars are giants or supergiants of intermediate and late spectral type showing considerable periodicity in their light changes, accompanied or sometimes interrupted by various irregularities. ... Serpens (the snake) is one of the 88 modern constellations, and was also one of the 48 listed by Ptolemy. ... Atmospheric pressure 0 kPa Setebos (set-e-bus) is Uranus outermost named moon, surpassed only by S/2001 U 2. ... SETI (pronounced , to rhyme with Betty) stands for Search for Extra-Terrestrial Intelligence. ... For the Ancient Roman coin denomination, see sextans (coin). ... A sextant is a measuring instrument used to measure the angle of elevation of a celestial object above the horizon. ... Seyfert galaxies are spiral or irregular galaxies containing an extremely bright nucleus, most likely caused by a supermassive black hole, that can sometimes outshine the surrounding galaxy. ... Seyferts Sextet. ... Carl Keenan Seyfert (February 11, 1911 – June 13, 1960) was an American astronomer. ... The shape of the Universe is a subject of investigation within cosmology. ... Harlow Shapley in his earlier years. ... Shaula appears as the 25th brightest star, and can be found in the tail of the constellation Scorpio. ... Shedir is the common name for Alpha Cassiopeiae, the brightest star in the northern constellation Cassiopeia. ... A planetary ring is a ring of dust and other small particles orbiting around a planet in a flat disc-shaped region. ... The shift-and-add method (more recently image-stacking method) is a form of speckle imaging commonly used for obtaining high quality images from a number of short exposures with varying image shifts. ... Iosif Samuilovich Shklovsky (Ио́сиф Самуи́лович Шкло́вский) (July 1, 1916 – March 3, 1985) was a Soviet/Russian astronomer and astrophysicist. ... Carolyn Jean Spellmann Shoemaker (born 1929) is a co-discoverer of Comet Shoemaker-Levy 9 and wife to Eugene Shoemaker. ... Eugene Shoemaker at a stereoscopic microscope used for asteroid discovery Eugene Merle Shoemaker (or Gene Shoemaker) (April 28, 1928 – July 18, 1997) was one of the founders of the fields of planetary science and is best known for co-discovering the Comet Shoemaker-Levy 9 with his wife Carolyn Shoemaker... James Short (June 10, 1710 – June 15, 1768) was an British mathematician, optician and telescope maker. ... Siarnaq (see-ar-naak) (Saturn XXIX) is a natural satellite of Saturn. ... On a prograde planet like the Earth, the sidereal day is shorter than the solar day. ... Sidereal astrology is the practice by some western and all Indian astrologers of basing their study of the sky on the actual position of the planets in relation to the starry background. ... On a prograde planet like the Earth, the sidereal day is shorter than the solar day. ... Sidereal time is time measured by the apparent diurnal motion of the vernal equinox, which is very close to, but not identical with, the motion of stars. ... The sidereal year is the time for the Sun to return to the same position in respect to the stars of the celestial sphere. ... The 2. ... Siding Spring Observatory, Coonabarabran, Australia. ... Atmospheric pressure 0 kPa Sinope (IPA: , si-noe-pee, Greek Σινώπη) is a moon of Jupiter discovered by Seth Barnes Nicholson at Lick Observatory in 1914, and is named after Sinope of Greek mythology. ... Sirius (α CMa / α Canis Majoris / Alpha Canis Majoris) is the brightest star in the nighttime sky, with a visual apparent magnitude of −1. ... This article is about the star. ... This article is about the star. ... In Celtic mythology, Sirona was a goddess worshipped predominantly in East Central Gaul and along the Danubian limes. ... Alpheratz, or α Andromedae, is the brightest star in the Andromeda constellation, which is located immediately northwest of Pegasus. ... Sirsalis is a relatively young lunar impact crater located near the western lunar limb, to the southwest of the Oceanus Procellarum. ... Willem de Sitter (May 6, 1872 – November 20, 1934) was a mathematician, physicist and astronomer. ... Skathi (skaadh-ee, with a voiced th as in this) (Saturn XXVII) is a natural satellite of Saturn. ... The sky of a world refers to the view of the heavens from its surface. ... A typical daytime sky. ... Drawing of Skylab with components labelled Skylab was the first space station the United States launched into orbit. ... The Small Magellanic Cloud (SMC) —also known as NGC 292— is an irregular galaxy, sometimes classified as a dwarf galaxy, in orbit around the Milky Way Galaxy. ... The small-angle formula is a mathematical approximation, used in astronomy. ... Francis Smith can refer to: Francis Smith (astronomer), British astronomer Francis Smith (politician), Premier of Tasmania This is a disambiguation page — a navigational aid which lists other pages that might otherwise share the same title. ... The Smithsonian Astrophysical Observatory (SAO) is a research institute of the Smithsonian Institution headquartered in Cambridge, Massachusetts, where it is joined with the Harvard College Observatory (HCO) to form the Harvard-Smithsonian Center for Astrophysics (CfA). ... William Henry Smyth (January 21, 1788 – September 9, 1865) was a British astronomer. ... Supernova 1604, also known as Keplers Supernova or Keplers Star, was a supernova in the Milky Way, in the constellation Ophiuchus. ... Snells law is the simple formula used to calculate the refraction of light when travelling between two media of differing refractive index. ... The Southern Astrophysical Research Telescope (SOAR) is located on Cerro Pachón, Chile, and operated by a consortium including Michigan State University, the University of North Carolina at Chapel Hill, the National Optical Astronomy Observatory and the country of Brazil. ... [[[[Media: Soft X-ray trans]]ients ]] (often abbreviated to SXT) are also known as X-ray novae. ... A soft gamma repeater is an astronomical object, now known to be a type of magnetar, which emits large bursts of gamma rays and X-rays at irregular intervals. ... Presentation of the solar system (not to scale) The solar system comprises the Earths Sun and the retinue of celestial objects gravitationally bound to it. ... 20 years of solar irradiance data from satellites Solar variation refers to fluctuation in the amount of energy emitted by the Sun. ... The Solar and Heliospheric Observatory (SOHO) is a spacecraft that was launched on 2 December 1995 to study the sun, and began normal operations in May 1996. ... A solar calendar is a calendar whose dates indicate the position of the earth on its revolution around the sun (or equivalently the apparent position of the sun moving on the celestial sphere). ... Solar cosmic rays are cosmic rays that originate from the Sun. ... It has been suggested that this article or section be merged with Schwabe-Wolf cycle. ... Solar time is based on the idea that, when the sun reaches its highest point in the sky, it is noon. ... Photo taken during the 1999 eclipse. ... A Solar Flare, courtesy NASA A solar flare is a violent explosion in the Suns atmosphere with an energy equivalent to tens of millions of hydrogen bombs. ... The solar luminosity is a unit of luminosity (power emitted in the form of photons) conventionally used by astronomers to give the luminosities of stars. ... In astronomy, the solar mass is a unit of mass used to express the mass of stars and larger objects such as galaxies. ... Solar maximum or solar max is the period of greatest solar activity in the solar cycle of the sun. ... ã ... The solar neutrino problem was a major discrepancy between measurements of the neutrinos flowing through the Earth and theoretical models of the solar interior, lasting from the mid-1960s to about 2002. ... EIT 30. ... Solar irradiance spectrum at top of atmosphere. ... Concept image of a solar sail spacecraft in the process of unfurling sails. ... Presentation of the solar system (not to scale) The solar system comprises the Earths Sun and the retinue of celestial objects gravitationally bound to it. ... Solar time is based on the idea that when the sun reaches its highest point in the sky, it is noon. ... 20 years of solar irradiance data from satellites Solar variations are fluctuations in the amount of energy emitted by the Sun. ... The plasma in the solar wind meeting the heliopause For the British comic, see Solar Wind (comic). ... Solar year The period of time required for the earth to make one complete revolution around the sun, measured from one vernal equinox to the next. ... Diagram of the Earths seasons Solstice is an astronomical term regarding the position of the Sun in relation to the earths equator. ... M104, the Sombrero Galaxy. ... Sonneberg Observatory is an astronomical observatory was an institute of the Academy of Science in the German democratic republic. ... The Sothic cycle or Canicular period is a period of 1461 ancient Egyptian years (of 365 days) or 1460 Julian years (averaging 365. ... A compass rose with South highlighted South is most commonly a noun, adjective, or adverb indicating direction or geography. ... The South Pole Telescope or (SPT) is a project to build a submillimetre telescope at the South Pole. ... The South Pole-Aitken basin is an impact crater on Earths Moon. ... Location of the South Pole in the Antarctic continent. ... Computer model of SALTs external appearance. ... Southern Hemisphere The Southern Hemisphere is the half of a planets surface (or celestial sphere) that is south of the equator (the word hemisphere literally means half ball). On Earth it contains four continents (part of Africa, Oceania, most of South America, and Antarctica) and four oceans (South Atlantic... Messier Object 83, the Southern Pinwheel Galaxy. ... Southern Hemisphere The Southern Hemisphere is the half of a planets surface (or celestial sphere) that is south of the equator (the word hemisphere literally means half ball). On Earth it contains four continents (part of Africa, Oceania, most of South America, and Antarctica) and four oceans (South Atlantic... Space has been an occupation for philosophers and scientists for much of human history, and hence it is difficult to provide an uncontroversial and clear definition outside of specific defined contexts (except scientific definition of space in physics and mathematics - see below). ... The Space Interferometry Mission (SIM), is a NASA mission scheduled for launch in 2010, which will make astrometric observations to determine the positions and distances of stars several hundred times more accurately than any previous program. ... For other uses, see Space Race (disambiguation). ... The Space Shuttle Columbia seconds after engine ignition, 1981 (NASA). ... The Space Shuttle orbiter Atlantis landing in 1997 Space Shuttle Orbiter Atlantis (NASA Orbiter Vehicle Designation: OV-104) is one of five NASA space shuttles. ... Space Shuttle Columbia (NASA Orbiter Vehicle Designation: OV-102) was the first space shuttle in NASAs orbital fleet. ... Shuttle Orbiter Discovery (NASA Orbiter Vehicle Designation: OV-103) is a NASA Space Shuttle. ... Shuttle Orbiter Endeavour (NASA Orbiter Vehicle Designation: OV-105), is the fifth and final, and therefore, the youngest and newest, operational NASA space shuttle to be built. ... The Space Telescope Science Institute (STScI) is an organization founded by NASA to manage and direct research done with the Hubble Space Telescope. ... Space exploration is the physical exploration of outer space objects and generally anything that involves the technologies, science, and politics regarding space endeavors. ... A space observatory is any instrument in outer space which is used for observation of distant planets, galaxies, and other outer space objects. ... A space probe is an unmanned space mission in which a spacecraft leaves Earths orbit. ... Space science, or the space sciences, are fields of science that are concerned with the study or utilization of outer space. ... The space station Mir A space station is an artificial structure designed for humans to live in space, so far only low earth orbit. ... A space observatory is any object in outer space which is used for observation of distant planets, galaxies, and other outer space objects. ... Aurora australis observed by Discovery, May 1991 Space weather is the concept of changing environmental conditions in outer space. ... An Ariane 5 expendable launch vehicle lifts off with the Rosetta spacecraft on March 2, 2004. ... World line of the orbit of the Earth depicted in two spatial dimensions X and Y (the plane of the Earth orbit) and a time dimension, usually put as the vertical axis. ... Spacewatch is a project at the University of Arizona that specializes in the study of minor planets, and including various types of asteroids and comets. ... In astrodynamics the specific orbital energy (or vis-viva energy) of an orbiting body traveling through space under standard assumptions is the sum of its potential energy () and kinetic energy () per unit mass. ... Typical short-exposure image of a binary star (Zeta Bootis in this case) as seen through atmospheric seeing. ... In astronomy the term spectral class refers to classifying objects according to their spectral lines, which indicate an objects chemical composition. ... In astronomy, stellar classification is a classification of stars based initially on photospheric temperature and its associated spectral characteristics, and subsequenly refined in terms of other characteristics. ... In applied mathematics and physics, the spectral density is a general concept applied to a signal which may have any physical dimensions or none at all. ... A spectral line is a dark or bright line in an otherwise uniform and continuous spectrum, resulting from an excess or deficiency of photons in a narrow frequency range, compared with the nearby frequencies. ... In astronomy, stellar classification is a classification of stars based initially on photospheric temperature and its associated spectral characteristics, and subsequenly refined in terms of other characteristics. ... For Acoustic uses in spectrographs of sound waves, see below. ... The spectroheliograph is an instrument used in astronomy. ... A spectrometer is an optical instrument used to measure properties of light over a specific portion of the electromagnetic spectrum. ... Spectroscopy is the study of spectra, ie. ... A spectroscope is a device which measures the spectrum of light. ... A spectroscopic binary star is a binary star which cannot be resolved as a visual binary, even with telescopes of the highest existing resolving power. ... Extremely high resolution spectrum of the Sun showing thousands of elemental absorption lines (fraunhofer lines) Spectroscopy is the study of spectra, that is, the dependence of physical quantities on frequency. ... Spectrum-X-Gamma (SXG) is an international high-energy astrophysics observatory which is being built under the leadership of the Russian Space Research Institute (IKI). ... The speed of gravity is the speed at which changes in the location of an object propagate their gravitational effects to all other objects in the Universe. ... Cherenkov effect in a swimming pool nuclear reactor. ... Focal plane Longitudinal sections In optics, spherical aberration is an image imperfection that occurs due to the increased refraction of light rays that occurs when rays strike a lens or mirror near its edge, in comparison with those that strike nearer the center. ... Spica (α Vir / α Virginis / Alpha Virginis) is the brightest star in the constellation Virgo, and one of the brightest stars in the nighttime sky. ... A spiral galaxy presents a face-on view of its spiral arms. ... A spiral galaxy is a type of galaxy in the Hubble sequence which is characterized by the following physical properties: Spiral Galaxy M74 presents a face-on view of its spiral arms. ... The Spitzer Space Telescope Facility launches from Cape Canaveral Air Force Station in Florida on Monday, Aug. ... Spörers law predicts the variation of sunspot latitudes during a solar cycle. ... Sporus of Nicaea was a Greek mathematician and astronomer, born: circa 240, probably Nicaea (Greek Nikaia), ancient district Bithynia, (modern-day Iznik) in province Bursa, in modern day Turkey, died: circa 300. ... A spotting scope is a portable telescope, optimized for the observation of terrestrial objects. ... Sputnik 1 (Russian: , Satellite 1) was the first artificial satellite to be put into orbit, on October 4, 1957. ... This article needs to be cleaned up to conform to a higher standard of quality. ... The Standard Model of Fundamental Particles and Interactions The Standard Model of particle physics is a theory which describes the strong, weak, and electromagnetic fundamental forces, as well as the fundamental particles that make up all matter. ... A standard candle is an astronomical object that has a known luminosity. ... In astrodynamics, the standard gravitational parameter () of a celestial body is the product of the gravitational constant () and the mass : The units of the standard gravitational parameter are km3s-2 Small body orbiting a central body Under standard assumptions in astrodynamics we have: where: is the mass of the orbiting... The Standard Model of Fundamental Particles and Interactions The Standard Model of particle physics is a theory which describes the strong, weak, and electromagnetic fundamental forces, as well as the fundamental particles that make up all matter. ... The Pleiades star cluster A star is a massive body of plasma in outer space that is currently producing or has produced energy through nuclear fusion. ... In astronomy, many stars are referred to simply by catalogue numbers. ... Globular Cluster M92 in the Hercules constellation. ... The International Astronomical Union (IAU) is the internationally recognised authority for assigning designations to stars (and other celestial bodies). ... Star formation is the process by which gas in molecular clouds change into the ball of plasma we call a star. ... A star party is a gathering of amateur astronomers for the purpose of observing the sky. ... A star system or stellar system is a system comprised of a star or group of stars, with possibly planetary systems of smaller bodies (such as planets or asteroids), in close gravitational association. ... A starburst galaxy is a galaxy in the process of an intense burst of star formation, often as a result of a collision or close encounter between two galaxies. ... A starburst galaxy is a galaxy undergoing an episode of very active star formation. ... Chandra image of NGC 6420. ... The Starlink Project was a UK astronomical computing project, which supplied general-purpose data reduction software. ... For alternate meanings see star (disambiguation) Hundreds of stars are visible in this image taken by the Hubble Space Telescope of the Sagittarius Star Cloud in the Milky Way Galaxy. ... In cosmology, the steady state theory (also known as the Infinite Universe Theory or continuous creation) is a model developed in 1948 by Fred Hoyle, Thomas Gold, Hermann Bondi and others as an alternative to the Big Bang theory (known, usually, as the standard cosmological model). ... A stellar association is a very loose star cluster, looser than both open clusters and globular clusters. ... Stellar astronomy is the study of stars and the phenomena exhibited by the various forms/developmental stages of stars. ... In astronomy, stellar classification is a classification of stars based initially on photospheric temperature and its associated spectral characteristics, and subsequently refined in terms of other characteristics. ... Stellar dynamics is the branch of astrophysics which describes in a statistical way the collective motions of stars subject to their mutual gravity. ... In astronomy, stellar evolution is the sequence of changes that a star undergoes during its lifetime, the hundreds of thousands, millions or billions of years during which it emits light and heat. ... Cross section of a red giant showing nucleosynthesis and elements formed Stellar nucleosynthesis is the collective term for the nuclear reactions taking place in stars to build the nuclei of the heavier elements. ... A massive cosmic dust cloud in which microscopic particles may slowly aggregrate due to gravitational attraction and eventually give rise to protostars and subsequently solar systems, with one or more stars and planets. ... Stars can be grouped into two general types called Population I and Population II. The criteria for classification include space velocity, location in the galaxy, age, chemical composition, and differences in distribution on the Hertzsprung-Russell diagram. ... A solar wind is a stream of particles (mostly high-energy protons ~ 500 keV) which are ejected from the upper atmosphere of a star (in the case of a star other than the Earths Sun, it may be called a stellar wind instead). ... Atmospheric pressure 0 kPa Stephano (stef-a-noe or ste-faa-noe) is a natural satellite of Uranus. ... Stephen P. Synnott is a Voyager scientist who discovered several moons of Jupiter, Saturn, Uranus, and Neptune. ... Steven Weinberg at Harvard University Steven Weinberg (born May 3, 1933) is an American physicist. ... Simon Stevin Simon Stevin (1548/49 – 1620) was a Flemish mathematician and engineer. ... Steward Observatorys main office is located on the University of Arizona campus. ... The stratosphere is a layer of Earths atmosphere that is stratified in temperature, with warmer layers higher up and cooler layers farther down. ... The 747 which will house NASAs Stratospheric Observatory for Infrared Astronomy (SOFIA) on a test flight in 1997. ... Interaction in the subatomic world: world lines of pointlike particles in the Standard Model or a world sheet swept up by closed strings in string theory String theory is a model of fundamental physics whose building blocks are one-dimensional extended objects (strings) rather than the zero-dimensional points (particles... Janez Strnad (born March 4, 1934) is a Slovene physicist and populariser of natural science. ... The strong interaction or strong force is today understood to represent the interactions between quarks and gluons as detailed by the theory of quantum chromodynamics. ... The strong nuclear force or strong interaction (also called color force or colour force) is a fundamental force of nature which affects only quarks and antiquarks, and is mediated by gluons in a similar fashion to how the electromagnetic force is mediated by photons. ... The Space Telescope Science Institute (STScI) is an organization founded by NASA to manage and direct research done with the Hubble Space Telescope. ... The Subaru at sunset Subaru Telescope (In Japanese: すばる望遠鏡) is the 8. ... A subcluster or subclump (or subgroup) is a term used in galactic astronomy to include a identifiable isolated grouping of galaxies within a cluster of galaxies, typically centered on a large dominant member. ... A subdwarf star, sometimes denoted by sd, is luminosity class VI under the Yerkes spectral classification system. ... The submillimeter array under construction in 2002 The Submillimeter Array consists of 8 6 m diameter radio telescopes arranged as an interferometer for submillimeter wavelength observations. ... Submillimetre Astronomy is the branch of observational astronomy that is conducted at submillimetre wavelengths. ... Artists concept of SNOs detector. ... Illumination of Earth by the sun on the northern hemisphere summer solstice The summer solstice is an astronomical term regarding the position of the sun in relation to the celestial equator. ... The Sun is the spectral type G2V yellow star at the center of Earths solar system. ... An unusually pronounced sundog produced by sunlight passing through thin cirrus clouds. ... Wall sundial Wall sundial in Warsaws Old Town Pocket size sundial A sundial measures time by the position of the sun. ... The Sunflower Galaxy (also known as Spiral Galaxy M63, Messier Object 63, Messier 63, M63, or NGC 5055) is a spiral galaxy in the Canes Venatici constellation. ... Prism splitting light Sunlight in the broad sense is the total spectrum of electromagnetic radiation given off by the Sun. ... Sunrise over the sea Sunrise, also called sunup in some American English dialects, is the time at which the first part of the Sun appears above the horizon in the east. ... A red sunset panorama Sunset, also called sundown in some American English dialects, is the time at which the Sun disappears below the horizon in the west. ... A sunspot is a region on the Suns surface (photosphere) that is marked by a lower temperature than its surroundings and intense magnetic activity, which inhibits convection, forming areas of low surface temperature. ... The Sunyaev-Zeldovic Array (SZA) in California is surveying the Cosmic Microwave Background to find clusters of galaxies. ... The Sunyaev-Zeldovich effect (occasionally abbreviated as the SZ effect) is due to high energy electrons distorting the cosmic microwave background radiation (CMB) through inverse Compton scattering, in which some of the energy of the electrons is transferred to the low energy photons. ... Super-Kamiokande, or Super-K for short, is a neutrino observatory in Japan. ... SuperWASP consists of two camera arrays, one in the Northern Hemisphere at Roque de los Muchachos Observatory, and one in the Southern Hemisphere at the South African Astronomical Observatory designed to search for extrasolar planets. ... Superclusters are large groupings of smaller galaxy groups and clusters, and are among the largest structures of the cosmos. ... Supergiants are the most massive stars. ... In theoretical physics, a supergravity theory is a field theory combining supersymmetry and general relativity. ... The terms inferior planet and superior planet were coined by Copernicus to distinguish a planets orbits size in relation to the Earths. ... In astronomy, superluminal motion is the apparently faster-than-light motion seen in some radio galaxies, quasars and recently also in some galactic sources called microquasars. ... Top: artists conception of a supermassive black hole drawing material from a nearby star. ... Multiwavelength X-ray image of the remnant of Keplers Supernova, SN 1604. ... Supernova 1604, also known as Keplers Supernova or Keplers Star, was a supernova in the Milky Way, in the constellation Ophiuchus. ... 1987A supernova remnant near the center SN 1987A was a supernova in the Large Magellanic Cloud, a nearby dwarf galaxy. ... Composite image of Keplers supernova from pictures by the Spitzer Space Telescope, Hubble Space Telescope, and Chandra X-ray Observatory. ... Remnant of Keplers Supernova, SN 1604. ... Superstring theory is an attempt to explain all of the particles and fundamental forces of nature in one theory by modeling them as vibrations of tiny supersymmetric strings. ... This article is in need of attention from an expert on the subject. ... Surface brightness is a concept used in astronomy when describing extended astronomical objects such as galaxies and nebulae. ... Suttungr (soot-oong-ur) (Saturn XXIII) is a natural satellite of Saturn. ... The Swedish Solar Telescope (or SST) is a 1m telescope on La Palma in the Canary Islands. ... The Swift Gamma-Ray Burst Mission consists of an unmanned spacecraft called Swift, which was launched into orbit on November 20, 2004, at 17:16:00 UTC (12:16 PM, EST) on top of a Delta 2 rocket. ... Atmospheric pressure 0 kPa Sycorax (sik-or-aks) is a moon of Uranus. ... Chinese Celestial symbols on an antique bronze mirror Astronomical symbols are symbols used to represent various celestial objects, theoretical constructs and observational events in astronomy. ... In astronomy, synchronous rotation is a planetological term describing a body orbiting another, where the orbiting body takes as long to rotate on its axis as it does to make one orbit; and therefore always keeps the same hemisphere pointed at the body it is orbiting. ... Hannes Alfvén, and Nicolai Herlofson, predicted synchrotron radiation in space in 1950 [1] Synchrotron radiation is electromagnetic radiation, similar to cyclotron radiation, but generated by the acceleration of ultrarelativistic (i. ... A synodic day is the period of time it takes for a planet to rotate once in releation to the body it is orbiting (as opposed to a sidereal day which is one complete rotation in relation to the stars). ... In Egyptian mythology, Month is an alternate spelling for Menthu. ... The orbital period is the time it takes a planet (or another object) to make one full orbit. ... Syrma (ι Vir / ι Virginis / iota Virginis) is a star in the constellation Virgo. ... Syzygy may refer to any one of several different concepts or things, many of which ultimately derive their meaning from the Greek σύζῠγος (syzygos), yoked together. ...

T

T Tauri stars are a class of variable stars named after their prototype - T Tauri. ... T Tauri stars are a class of variable stars named after their prototype T Tauri. ... T-type asteroids are rare inner-belt asteroids of unknown composition with dark, featureless and moderately red spectra, and a moderate absorption feature shortwards of 0. ... U.S. Space Shuttle astronaut Bruce McCandless II using a manned maneuvering unit. ... Naoko Takeuchi (武内直子 Takeuchi Naoko), born March 15, 1967, is a manga artist who lives in Tokyo, Japan. ... The Tarantula Nebula. ... Tarvos (tar-vus) (Saturn XXI) is a natural satellite of Saturn. ... Tau Ceti (Ï„ Cet / Ï„ Ceti) is a star commonly mentioned by science fiction authors since it is similar to the Sun in mass and spectral type in addition to being relatively close to us. ... Taurus (Latin for bull, symbol , Unicode ♉) is one of the constellations of the zodiac. ... Teegardens Star, also known as SO025300. ... A tektite Tektites (from Greek tektos, molten) are natural glass objects, up to a few centimeters in size, which — according to most scientists — have been formed by the impact of large meteorites on Earths surface, although a few researchers favor an origin from the Moon as volcanic ejecta. ... 50 cm refracting telescope at Nice Observatory. ... There is a strong tradition of amateur telescope making within the amateur astronomy community. ... In astronomy, the telescope mount is an important part of the overall design of an operational telescope. ... The Telescopio Carlos Sánchez is a 1. ... The Telescopio Nazionale Galileo, or TNG is a 3. ... Telescopium (Latin for Telescope) is a minor southern constellation identified and named by Nicolas Louis de Lacaille, the 18th century French astronomer, a student of the southern skies. ... Atmosphere none Telesto (te-les-toe, Greek Τελεστώ) is a moon of Saturn. ... World map with terminator A composite image showing the terminator crossing Europe and Africa The terminator is the line between the illuminated, day side and dark, night side of a planetary body (also known as the grey line). It is defined as the locus of points on a moon or... Artists conception of a terraformed Mars in three stages of development. ... Terrestrial Planet Finder - Infrared interferometer concept The Terrestrial Planet Finder (TPF) is a mothballed NASA telescope system that would be capable of detecting extrasolar terrestrial planets. ... This article is about terrestrial time; for other meanings of TT, see TT (disambiguation). ... A terrestrial planet or telluric planet is a planet which is primarily composed of silicate rocks. ... Atmosphere none Tethys (tee-this or teth-is, Greek Τηθύς) is a moon of Saturn that was discovered by Giovanni Domenico Cassini in 1684. ... Abul Hasan Thabit ibn Qurra ibn Marwan al-Sabi al-Harrani, (826 – February 18, 901) was an Arab astronomer and mathematician. ... A simulated view of Thalassa orbiting Neptune. ... Thales of Miletus (ca. ... The Big Ear was a radio telescope located on the grounds of the Ohio Wesleyan Universitys The Perkins Observatory from the 1960s to 1998 when it was disassembled. ... Atmospheric pressure 0 kPa Thebe (thee-bee, IPA ; Greek Θήβη) is the fourth of Jupiters known moons by distance from the planet. ... On April 28, 1905, William H. Pickering, who had seven years earlier discovered Phoebe, announced the discovery of a tenth satellite of Saturn, which he promptly named Themis. ... Atmospheric pressure 0 kPa Themisto (IPA: , the-mis-toe, Greek Θεμιστώ) (Jupiter XVIII) is a moon of Jupiter. ... Thomas Young, English scientist Thomas Young (June 13, 1773 – May 10, 1829) was an English scientist and researcher. ... Kip S. Thorne Professor Kip Stephen Thorne, Ph. ... In astronomy, a Thorne-Zytkow object is a hypothetical type of star, a red giant that contains a neutron star inside it. ... Thrymr (THRIM er) is a natural satellite of Saturn. ... The star (or star system) Thuban, also known as α Draconis (alpha Draconis), is a star in the constellation of Draco. ... The tidal acceleration of the Moon is a peculiar effect in the dynamics of the Earth-Moon system, that has important long-term consequences for the orbit of the Moon and the rotation of the Earth. ... Comet Shoemaker-Levy 9 after breaking up under the influence of Jupiters tidal forces. ... Tidal locking makes one side of an astronomical body always face another, like the Moon facing the Earth. ... In oceanography, tidal resonance is a phenomenon perhaps best exemplified in the Bay of Fundy. ... The tide is the regular rising and falling of the oceans surface caused by changes in gravitational forces external to the Earth. ... This article or section is in need of attention from an expert on the subject. ... Timeline of artificial satellites and space probes Key: Year - Origin - Target - Status – Description // 1950s 1957 - Russia - Earth - Success - Sputnik 1 is launched, the first Earth orbiting satellite 1957 - Russia - Earth - Partial success - Sputnik 2 is launched, the first Earth orbiting satellite with an animal (Laika) 1958 - USA - Earth - Success - Explorer... Timeline of astronomical maps, catalogs and surveys 1800 BC - Babylonian star catalog 350 BC - Shin Shens star catalog has almost 800 entries 300 BC - star catalog of Timocharis of Alexandria 134 BC - Hipparchus makes a detailed star map ca. ... Timeline of black hole physics 1640 - Ismael Bullialdus suggests an inverse-square gravitational force law 1684 - Isaac Newton writes down his inverse-square Law of universal gravitation 1758 - Rudjer Josip Boscovich developes his Theory of forces, where gravity can be repulsive on small distances. ... Timeline of cosmic microwave background astronomy 1934 - Richard Tolman shows that black-body radiation in an expanding universe cools but remains thermal 1941 - Andrew McKellar uses the excitation of CN doublet lines to measure that the effective temperature of space is about 2. ... The timeline of cosmology lists the sequence of cosmological theories and discoveries in chronological order. ... Timeline of galaxies, clusters of galaxies, and large-scale structure of the cosmos 964 - Al Sufi, a Persian astronomer makes the first preserved recording of the Large Magellanic Cloud. ... Timeline of galaxies, clusters of galaxies, and large-scale structure of the cosmos 964 - Al Sufi, a Persian astronomer makes the first preserved recording of the Large Magellanic Cloud. ... Timeline of the interstellar medium and intergalactic medium 1848 - Lord Rosse studies M1 and names it the Crab Nebula 1864 - William Huggins studies the spectrum of the Orion Nebula and shows that it is a cloud of gas 1927 - Ira Bowen explains unidentified spectral lines from space as forbidden transition... Timeline of other background radiation fields 1912 - Victor Hess discovers that the ionization of air increases with altitude indicating the existence of cosmic radiation 1949 - Herbert Friedman detects evidence for extrasolar X-rays 1962 - Riccardo Giacconi, Herbert Gursky, F. Paolini, and Bruno Rossi formally discover the X-ray background Categories... Timeline of solar astronomy 1613 - Galileo Galilei uses sunspot observations to demonstrate the rotation of the Sun 1619 - Johannes Kepler postulates a solar wind to explain the direction of comet tails 1802 - William Hyde Wollaston observes dark lines in the solar spectrum 1814 - Joseph Fraunhofer systematically studies the dark lines... Timeline of solar system astronomy 2137 BC October 22 - Chinese astronomers record a solar eclipse 586 BC - Thales of Miletus predicts a solar eclipse 350 BC - Aristotle argues for a spherical Earth using lunar eclipses and other observations 280 BC - Aristarchus uses the size of the Earths shadow on... Timeline of stellar astronomy 134 BC - Hipparchus creates the magnitude scale of stellar apparent luminosities 1596 - David Fabricius notices that Miras brightness varies 1672 - Geminiano Montanari notices that Algols brightness varies 1686 - Gottfried Kirch notices that Chi Cygnis brightness varies 1718 - Edmund Halley discovers stellar proper motions... Timeline of telescopes, observatories, and observing technology. ... Timeline of telescopes, observatories, and observing technology. ... To meet Wikipedias quality standards, this article or section may require cleanup. ... Timeline of white dwarfs, neutron stars, and supernovae Note that this list is mainly about the development of knowledge, but also about some supernovae taking place. ... Timeline of white dwarfs, neutron stars, and supernovae Note that this list is mainly about the development of knowledge, but also about some supernovae taking place. ... Timocharis of Alexandria (circa 320 BC - 260 BC) was a Greek astronomer and philosopher. ... A tip-tilt mirror is a rapidly moving mirror that can make small rotations around its two axis. ... Atmospheric characteristics Pressure 146. ... Atmospheric pressure   Titania (ti-taan-ee-É™ or tye-tan-ee-É™) is the largest moon of Uranus. ... Johann Daniel Titius. ... The Titius-Bode law (or Bodes law) is the observation that orbits of planets in the solar system closely follow a simple geometric rule. ... Gerard of Cremona (1114–1187) edited for Latin readers the Tables of Toledo (Toledan Tables), the most accurate compilation of astronomical data ever seen in Europe at the time. ... Tom Gehrels is a Dutch-American astronomer. ... Clyde William Tombaugh (February 4, 1906 – January 17, 1997) was an American astronomer who discovered the planet Pluto in 1930. ... The shape of the universe is a subject of investigation within cosmology. ... The Torino Scale is a method for categorizing the impact hazard associated with near-Earth objects (NEOs) such as asteroids and comets. ... TPoint is computer software that implements a mathematical model of conditions leading to errors in telescope pointing and tracking, and adjusts the telescopes pointing and tracking to compensate for them. ... It has been suggested that this article or section be merged with Tracing. ... A trans-Neptunian object (TNO) is any object in the solar system which orbits the sun at a greater distance on average than Neptune. ... Deimos transits the Sun, as seen by Mars Rover Opportunity on March 4, 2004 The word transit has two meanings in astronomy: A transit is the astronomical event that occurs when one celestial body appears to move across the face of another celestial body, as seen by an observer at... Deimos transits the Sun, as seen by Mars Rover Opportunity on March 4, 2004 A transit of Deimos across the Sun as seen from Mars takes place when Deimos passes directly between the Sun and a point on the surface of Mars, obscuring a small part of the Suns... Earth and Moon transiting the Sun in 2084, as seen from Mars Earth and Moon from Mars, as imaged by Mars Global Surveyor A transit of Earth across the Sun as seen from Mars takes place when the planet Earth passes directly between the Sun and Mars, obscuring a small... A transit of Mercury across the Sun takes place when the planet Mercury comes between the Sun and the Earth, and Mercury is seen as a small black dot moving across the face of the Sun. ... Phobos transits the Sun, as seen by Mars Rover Opportunity on March 10, 2004 A transit of Phobos across the Sun as seen from Mars takes place when Phobos passes directly between the Sun and a point on the surface of Mars, obscuring a large part of the Suns... The 2004 transit of Venus A transit of Venus across the Sun takes place when the planet Venus passes directly between the Sun and the Earth, obscuring a small portion of the Suns disc. ... Triangulum is a small northern constellation whose three brightest stars, of third and fourth magnitude, form an elongated triangle. ... Triangulum Australe is a small southern constellation whose three brightest stars, of second and third magnitude, form an approximately equilateral triangle. ... Messier Object 33, the Triangulum Galaxy. ... The Trifid Nebula (also known as M20 and NGC 6514) is an H II region at right ascension 18h 02. ... Atmospheric pressure 0 kPa Trinculo (tring-kew-loe) is a natural satellite of Uranus. ... A triple star system consists of three gravitationally bound stars. ... The triple alpha process is the process by which three helium nuclei (alpha particles) are transformed into carbon. ... Triton (trye-tÉ™n, IPA , Greek Τρίτων), or Neptune I, is the planet Neptunes largest moon. ... Image of the Trojan asteroids in front of and behind Jupiter along its orbital path. ... The tropical zodiac is a zodiac based upon tropical time, or the apparent motion of the Sun across the sky over the course of a year. ... Tucana (Latin for Toucan) is a southern constellation. ... In astronomy, the Tully-Fisher relation, published by astronomers R. Brent Tully and J. Richard Fisher in 1977, is a standard candle that measures the distance to rotating spiral galaxies by the width of the galaxys spectral lines. ... Trees felled by the Tunguska blast. ... In fluid dynamics, turbulence or turbulent flow is a flow regime characterized by chaotic, stochastic property changes. ... It has been suggested that this article or section be merged with Dawn. ... The twin paradox, sometimes called the clock paradox, stems from Paul Langevins 1911 thought experiment in special relativity: one of two twin brothers undertakes a long space journey with a high-speed rocket at almost the speed of light, while the other twin remains on Earth. ... Richard Q. Twiss (? – 20 May 2005) is famous for his work on the Hanbury-Brown and Twiss effect with Robert Hanbury Brown. ... In mechanics, the two-body problem is a special case of the n-body problem that admits a closed form solution. ... While a Plutino completes 2 orbits around the Sun in the time it takes Neptune to complete 3 orbits, a Twotino makes 1 orbit around the Sun in the time it takes Neptune to complete 2 orbits. ... Tycho is: The first name of Tycho Brahe, a Danish nobleman, well known as an astronomer/astrologer A crater on the moon named after him; see Tycho (crater) A crater on Mars named after him; the Tycho Brahe crater The alias of American song writer / producer Scott Hansen A character... Tychonic system The Tychonic system (or Tychonian system) was an effort by Tycho Brahe to create a model of the solar system which would combine what he saw as the mathematical benefits of the Copernican system with the philosophical and physical benefits of the Ptolemaic system. ... Tzolkin is the name given to the 260-day sacred calendar of the Maya. ...

U

The UBC Liquid-Mirror Observatory was made in 1995 for testing of liquid-mirror telescope technology. ... UHURU is the Swahili word for freedom. ... The 1. ... UKIRT, the United Kingdom Infra-Red Telescope, is a 3. ... The ultimate fate of our universe is a topic in cosmology. ... Ulugh Beg, here depicted on a Soviet stamp, was one of Islams greatest astronomers during the Middle Ages. ... Umbra and penumbra. ... Atmospheric pressure 0 kPa Umbriel (um-bree-É™l, IPA ) is a moon of Uranus discovered on 1851-10-24 by William Lassell. ... UFO redirects here. ... Aerial view of USNO. The United States Naval Observatory (USNO) is one of the oldest scientific agencies in the United States. ... Unmanned space missions are those using remote-controlled spacecraft. ... In the Lunar geologic timescale, the Upper Imbrian epoch occurred between 3800 million years ago to about 3200 million years ago. ... The house of Anders Celsius with his observatory on the roof, from a contemporary engraving. ... The Uppsala General Catalogue of Galaxies (UGC) is a catalogue of 12921 galaxies visible from the northern hemisphere. ... Upsilon Andromedae (Ï… And ) is a star, approximately 44 light-years from Earth, and approximately 3 billion years old, two thirds the age of our Sun. ... Simon Vouet, The Muses Urania and Calliope, c. ... Uraniborg was the astronomical/astrological observatory of Tycho Brahe; built circa 1576-1580 on Hven (also known as Ven or Hveen), an island in the Öresund; between Zealand and Scania. ... Uranometrias engraving of the constellation Orion, courtesy of the US Naval Observatory Library Uranometria is the short title of a star atlas produced by Johann Bayer. ... Atmospheric characteristics Atmospheric pressure 120 kPa Hydrogen 83% Helium 15% Methane 1. ... Uranus has 27 known moons. ... Ursa Major (Ursa Maior in Latin) is a constellation visible throughout the year in the northern hemisphere. ... The Ursa Major Moving Group is the closest moving group to Earth, with its core being located roughly 80 light years away. ... Ursa Minor is a constellation in the northern sky, the name of which means Small Bear in Latin. ... UV astronomy is the branch of astronomy and astrophysics which deals with objects visible in ultraviolet (UV) radiation. ...

V

The V-type asteroids or Vestoids are moderately bright, and very similar to the more common S-type, which are also made up of stony irons and ordinary chondrites. ... Yrjö Väisälä (IPA: ) (September 6, 1891 - July 21, 1971) was a Finnish astronomer and physicist. ... Van Allen radiation belts The Van Allen radiation belt is a torus of energetic charged particles ( a plasma) around Earth, trapped by Earths magnetic field. ... James Van Allen at National Air & Space Museum (NASM), 1981, Photo courtesy of NASM. Explorer I model and Pioneer H probe in background James Alfred Van Allen (born September 7, 1914) is considered Americas foremost space scientist. ... Johan Philip Lansberg (August 25, 1561–December 8, 1632) was a Dutch astronomer. ... Adriaan Van Maanen (March 31, 1884 – January 26, 1946) was a Dutch-American astronomer. ... Most stars are of almost constant luminosity. ... Variable stars are named using a variation on the Bayer designation format of Identifier <genitive of constellation>. In previous centuries few variable stars were known, so it seemed reasonable to use the letters of the Roman alphabet, starting from the letter R so as to avoid confusion with letter spectral... 20000 Varuna (VAR oo na) is a Kuiper Belt object about 1060 kilometers in diameter, estimated from a combination of thermal and optical measurements. ... Gérard Henri de Vaucouleurs (April 25, 1918–October 7, 1995) was a French-American astronomer. ... Vega (α Lyr / α Lyrae / Alpha Lyrae) is the brightest star in the constellation Lyra, and the fifth brightest star in the sky. ... Vela (Latin for sails) is a southern constellation, one of the four parts into which Argo Navis was split (the others being; Carina (constellation), Puppis and Pyxis. ... (*min temperature refers to cloud tops only) Atmospheric characteristics Atmospheric pressure 9. ... A Venus-crosser asteroid is an asteroid whose orbit crosses that of Venus. ... Illumination of Earth by Sun on the day of equinox The vernal equinox (or spring equinox) marks the beginning of astronomical spring. ... One of the four telescopes that make up the VLT, named Kueyen. ... VLBA locations. ... Very Long Baseline Interferometry (VLBI) is a type of astronomical interferometry used in radio astronomy, in which the data received at each antenna in the array is paired with timing information, usually from a local atomic clock, and then stored for later analysis on magnetic tape or hard disk. ... The Very Small Array is a 14-element interferometer perched at an elevation of 3000 metres on Tenerife in the Canary Islands. ... Vienna University Observatory Vienna Observatory is an astronomical observatory in Vienna, Austria. ... The Villafranca Satellite Tracking Station in Spain. ... Vindemiatrix (ε Vir / ε Virginis / epsilon Virginis) is a star in the constellation Virgo. ... The jet emitted by M87 in this image is thought to be caused by a supermassive black hole at the galaxys center. ... The Virgo Supercluster or Local Supercluster is the supercluster of galaxies that contains the Local Group and with it our galaxy, the Milky Way. ... A sky field near some of the brighter galaxies in the Virgo cluster. ... In physics, VIRGO is a project of France and Italy, a Michelson laser interferometer that is very analogous to LIGO. External link Virgo - description Categories: Physics stubs | Gravitational wave telescopes | Interferometers ... In physics, the virial theorem states that the average kinetic energy of a system of particles whose motions are bounded is given by where ri and Fi are the position and force vectors on the i th particle respectively. ... VISTA is the Visible & Infrared Survey Telescope for Astronomy, a 4m telescope in development which will be sited at Cerro Paranal in Chile. ... A visual binary star is a binary star for which the angular separation between the two components is great enough to permit them to be observed as a double star in a telescope. ... The apparent magnitude (m) of a star, planet or other heavenly body is a measure of its apparent brightness; that is, the amount of light received from the object. ... The Very Large Array (VLA) is a radio astronomy observatory located on the Plains of San Augustin, between the towns of Magdalena and Datil, some fifty miles (80 km) west of Socorro, New Mexico, USA. The VLA stands at , , at an altitude of 6970 ft (2124 m) above sea level. ... This article needs cleanup. ... The four telescopes of the European Southern Observatory Paranal site. ... The VLT Survey Telescope or VST is a proposed 2. ... The four telescopes of the European Southern Observatory Paranal site. ... Hermann Carl Vogel (April 3, 1841 – August 13, 1907) was a German astronomer. ... Categories: Astronomy stubs | Modern constellations | Constellations | Volans constellation ... Wernher von Braun stands at his desk in the Marshall Space Flight Center, Huntsville, Alabama in May 1964, with models of rockets developed and in progress. ... Friedrich Heinrich Alexander, Baron von Humboldt, (September 14, 1769, Berlin–May 6, 1859, Berlin), was a German naturalist and explorer, and the younger brother of the Prussian minister, philosopher, and linguist Wilhelm von Humboldt. ... John von Neumann in the 1940s. ... A NASA artists rendition of a Voyager spacecraft The Voyager 1 spacecraft is an 815-kilogram unmanned probe of the outer solar system and beyond, launched September 5, 1977, and currently operational. ... The Voyager 2 spacecraft was launched in 1977. ... The Voyager spacecraft Launch of Voyager 2 Voyager is also the name of a planned series of unmanned probes to Mars, cancelled in 1968. ... Vulcan was the name given to a small planet proposed to exist in an orbit between Mercury and the Sun, in a 19th century hypothesis which has now been superseded by Albert Einsteins theory of general relativity. ... Vulcanoids are hypothetical asteroids that may orbit in a dynamically stable zone between 0. ... Vulpecula, being Latin for Fox, is a faint northern constellation located in the middle of the Summer Triangle, an asterism consisting of the bright stars Deneb, Vega and Altair. ...

W

W Ursae Majoris (W UMa) is a variable star in the constellation Ursa Major. ... A W Virginis variable is a variable star similar to a Cepheid variable. ... The W cloud is a cloud cluster of galaxies approximately 25-30 megaparsecs distant. ... Richard Walker was also an equestrian who won the Badminton Horse Trials. ... Godefroy Wendelin (June 6, 1580 – 1667) or Vendelin was a Belgian astronomer. ... The Westerbork Synthesis Radio Telescope (WSRT) (near Westerbork (camp), north of Westerbork (village), m. ... Weyls postulate states that the world lines of the galaxies form a three-bundle of non-intersecting geodesics orthonormal to a series of space-like hypersurfaces. ... Hermann Weyl Hermann Weyl (November 9, 1885 - December 8, 1955) was a German mathematician. ... Wezen (δ Canis Majoris) is the name of a star in the constellation Canis Major. ... John Archibald Wheeler (born July 9, 1911) is an American theoretical physicist. ... The Whirlpool Galaxy (also known as Spiral Galaxy M51, Messier Object 51, Messier 51, M51, or NGC 5194) is a classic spiral galaxy located in the Canes Venatici constellation. ... White dwarf Sirius-B in x-rays A white dwarf is an astronomical object which is produced when a low or medium mass star dies. ... In astrophysics, a white hole is a postulated celestial body that is the time reversal of a black hole. ... Wiens displacement law is a law of physics that states that there is an inverse relationship between the wavelength of the peak of the emission of a black body and its temperature. ... Eugene Wigner (left) and Alvin Weinberg Eugene Paul Wigner (Hungarian Wigner Pál JenÅ‘) (November 17, 1902 – January 1, 1995) was a Hungarian physicist and mathematician who received the Nobel Prize in Physics in 1963 for his contributions to the theory of the atomic nucleus and the elementary particles, particularly... Willebrord Snel Willebrord Snel (1580–October 30, 1626), also known as Snel van Royen or Snellius, was a Dutch astronomer and mathematician, most famous for the law of refraction now known as Snells law. ... Sir William Hunter McCrea (13 December 1904 – April 25, 1999) was an astronomer and mathematician. ... Lord Rosse William Parsons, 3rd Earl of Rosse (June 17, 1800 – October 31, 1867) was an Irish astronomer. ... In 1769 a Scottish astronomer named Alexander Wilson noticed that the shape of sunspots noticeably flattened as they approached the Suns limb as the Sun rotated. ... This article is about the hypothetical class of particles. ... Illumination of Earth by Sun on the day of the northern hemisphere winter solstice Illumination of Earth by Sun on the day of the southern hemisphere winter solstice In astronomy, the winter solstice is the moment when the earth is at a point in its orbit where one hemisphere is... Carl Wilhelm Wirtz was an astronomer who spent his time between Germany and the Observatory of Strasbourg. ... Edward Witten at the Institute for Advanced Study Edward Witten (born August 26, 1951) is an American mathematical physicist, Fields Medalist, and professor at the Institute for Advanced Study. ... WIYN Consortium consists of the University of Wisconsin (W), Indiana University (I), Yale University (Y), and the National Optical Astronomy Observatories (N). ... Artist depiction of the WMAP satellite at the L2 point The Wilkinson Microwave Anisotropy Probe (WMAP) is a NASA satellite whose mission is to survey the sky to measure the temperature of the radiant heat left over from the Big Bang. ... Wolf 359 is a star located approximately 2. ... Maximilian Franz Joseph Cornelius Wolf (June 21, 1863 – October 3, 1932) was a German astronomer. ... Artists impression of a Wolf-Rayet star Wolf-Rayet stars (often referred to as WR stars) are evolved, hot, massive stars which have very strong stellar winds. ... Wolfe is a surname. ... Sir Arnold Wolfendale is a British astronomer. ... Aleksander Wolszczan (b. ... Sir Richard van der Riet Woolley (April 24, 1906 – December 24, 1986) was a British astronomer. ... Christopher Wren by Godfrey Kneller, 1711. ...

X

ROSAT image of X-ray fluorescence of, and occultation of the X-ray background by, the Moon. ... X-ray binaries are a class of binary stars that are very luminous in X-rays. ... X-ray bursters are a class of binary stars which have periodic outbursts luminous in X-rays. ... An X-ray pulsar is a neutron star with a powerful magnetic field that gives rise to regular X-ray pulses. ... The X-group of asteroids collects together several types with similar spectra, having largely metallic composition. ... Franz Xaver, Baron Von Zach Baron Franz Xaver von Zach (Franz Xaver Freiherr von Zach) (June 4, 1754 - September 2, 1832) was a German/Hungarian astronomer born at Pest. ... This article is about XMM-Newton. ...

Y

In physics, the Yarkovsky effect is a force felt by a body caused by the momentum carried away by the thermal photons that it emits. ... The 102 cm (40 inch) refractor at the Yerkes Observatory. ... The 102-cm (40 inch) refractor at the Yerkes Observatory. ... Ymir (ee-mur) (Saturn XIX) is a natural satellite of Saturn. ... The Yarkovsky-OKeefe-Radzievskii-Paddack effect, or YORP effect for short, is a second-order variation on the Yarkovsky effect which causes a small body (such as an asteroid) to spin up or down. ... Charles Augustus Young (December 15, 1834 – January 3, 1908) was an American astronomer. ... Yrjö Väisälä (IPA: ) (September 6, 1891 - July 21, 1971) was a Finnish astronomer and physicist. ...

Z

This article needs to be cleaned up to conform to a higher standard of quality. ... Beta Virginis (β Vir / β Virginis) is a star in the constellation Virgo. ... The Zeeman effect (IPA ) is the splitting of a spectral line into several components in the presence of a magnetic field. ... Pieter Zeeman (May 25, 1865 – October 9, 1943) (pronounced zāmän) was a physicist who shared the 1902 Nobel Prize in Physics with Hendrik Lorentz for his discovery of the Zeeman effect. ... The zenith, in astronomy, is the point in the sky which appears directly above the observer. ... In astronomy, the Zenithal Hourly Rate (ZHR) of a meteor shower is the number of meteors an observer would see in one hour under a clear, dark sky (limiting apparent magnitude of 6. ... Zeta Bootis imaged with the Nordic Optical Telescope on 13 May 2000 using the lucky imaging method. ... Zeta Reticuli (ζ Ret / ζ Reticuli) is a binary star system located about 39 light years away from Earth. ... Zhāng Héng Replica of Zhang Hengs seismometer Houfeng Didong Yi Zhang Heng (張衡, Pinyin: Zhāng Héng, Wade-Giles: Chang Heng) (78 – 139) was an astronomer, mathematician, inventor, artist and literary scholar of the Eastern Han Dynasty in ancient China. ... Zodiac signs, 16th century , medieval woodcuts The zodiac (from Greek zoon, animal) is an imaginary belt in the heavens extending approximately 8 degrees on either side of the Suns apparent path (the ecliptic), that includes the apparent paths of the Moon and the planets Mercury, Venus, Mars, Jupiter, and... The zodiacal light in the eastern sky before the beginning of morning twilight. ... Mars 3MV-4A Zond 3, a member of the Soviet Zond program, was the first Zond spacecraft to successfully complete its mission (a Lunar flyby) and took a number of amazing photographs for its time, though it is believed that it was initially intended to fly by Mars with Zond... The Zoroastrian calendar (sometimes referred to as the Persian calendar) has a year that is 365 days long, composed of 12 months of 30 days each, plus an additional period of 5 days at the end of the year. ... Fritz Zwicky (February 14, 1898 – February 8, 1974) was an American-based Swiss astronomer. ... The alpha reactions is one of two class of fusion reactions by which stars convert helium into heavier elements, the other being the triple_alpha process. ... The oxygen burning process is a nuclear fusion reaction that occurs in massive stars that have used up the lighter elements in their cores. ...



Contents: Top - 0–9 A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

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CalendarHome.com - Astronomy - Calendar Encyclopedia (1913 words)
Astronomical observations are not only relevant for astronomy as such, but provide essential information for the verification of fundamental theories in physics, such as general relativity theory.
Later, with the work of astronomers Kepler and Newton, whose work led to the development of celestial mechanics, the mathematical prediction of the motions of celestial bodies interacting gravitationally became the focus of astronomy.
East Asia's first astronomical observatory was developed in Silla, one of Three Kingdoms of Korea, under the reign of Queen Seondeok of Silla.
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