NationMaster - Encyclopedia: Uranus (planet)

Uranus (pronounced "yər-AYN-us", or "YOOR-ə-nus") is the seventh planet from the Sun. It is a gas giant, the third largest by diameter and fourth largest by mass. It was named after the Greek god Ouranos, and is the only planet in the solar system named after a Greek god: all others are named after Roman deities. Its symbol is either ♅ (Unicode U+2645, mostly astrological) or (mostly astronomical). Sir Wilhelm Friedrich Herschel (Hanover, November 15, 1738 – August 25, 1822 Slough, then in Buckinghamshire now in Berkshire) was a German-born British astronomer and composer who became famous for discovering the planet Uranus, and made many other astronomical discoveries. ... March 13 is the 72nd day of the year in the Gregorian calendar (73rd in leap years). ... 1781 was a common year starting on Monday (see link for calendar). ... 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. ... In astronomy, an epoch is a moment in time for which celestial coordinates or orbital elements are specified. ... The J2000. ... In geometry, the semi-major axis (also semimajor axis) a applies to ellipses and hyperbolas. ... A kilometre (American spelling: kilometer, symbol: km) is a unit of length equal to 1000 metres (from the Greek words khilia = thousand and metro = count/measure). ... The astronomical unit (AU or au or a. ... The circumference is the distance around a closed curve. ... Tera (symbol: T) is a prefix in the SI system of units denoting 1012, or 1 000 000 000 000. ... The metre (American spelling: meter), symbol: m, is the basic unit of distance (or of length, in the parlance of the physical sciences) in the International System of Units. ... (This page refers to eccitricity in astrodynamics. ... 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. ... The orbital period is the time it takes a planet (or another object) to make one full orbit. ... To help compare orders of magnitude of different times this page lists times between 109 seconds (a gigasecond) and 1010 seconds (32 years and 320 years). ... A Julian year is the length of an average year in the Julian calendar, 365. ... The orbital period is the time it takes a planet (or another object) to make one full orbit. ... 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. ... Inclination is one of the six orbital parameters describing the shape and orientation of a celestial orbit and is the angular distance of the orbital plane from the plane of the reference (usually planets equator or the ecliptic), stated in degrees. ... The Longitude of the ascending node () is one of the orbital elements used to specify the orbit of an object in space. ... The argument of the perihelion is one of the orbital elements describing the orbit of a planet. ... The common noun moon (not capitalized) is used to mean any natural satellite of the other planets. ... The equator is an imaginary line drawn around a planet, halfway between the poles. ... In geometry, a diameter (Greek words diairo = divide and metro = measure) of a circle is any straight line segment that passes through the center and whose endpoints are on the circular boundary, or, in more modern usage, the length of such a line segment. ... To help compare different orders of magnitude, this page lists lengths starting at 107 m (10,000 km). ... For other uses of the word pole, see Pole (disambiguation). ... 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... This article explains the meaning of area as a physical quantity. ... Square kilometre (US spelling: Square kilometer), symbol km², is an SI unit of surface area. ... Volume (also called capacity) is a quantification of how much space an object occupies. ... A cubic kilometre (symbol km³) is an SI derived unit of volume. ... Mass is a property of physical objects that, roughly speaking, measures the amount of matter they contain. ... The international prototype, made of platinum-iridium, which is kept at the BIPM under conditions specified by the 1st CGPM in 1889. ... Density (symbol: ρ - Greek: rho) is a measure of mass per unit of volume. ... Gravitation is the tendency of masses to move toward each other. ... Acceleration is the time rate of change of velocity, and at any point on a v-t graph, it is given by the gradient of the tangent to that point In physics, acceleration (symbol: a) is defined as the rate of change (or time derivative) of velocity. ... g (also gee, g-force or g-load) is a non-SI unit of acceleration defined as exactly 9. ... 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... This article is about retrograde motion. ... Axial tilt is an astronomical term regarding the inclination angle of a planets rotational axis in relation to its orbital plane. ... 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. ... In astronomy declination (dec) is one of the two coordinates of the equatorial coordinate system, the other being either right ascension or hour angle. ... The albedo is a measure of reflectivity of a surface or body. ... Temperature is the physical property of a system which underlies the common notions of hot and cold; the material with the higher temperature is said to be hotter. ... Temperature is the physical property of a system which underlies the common notions of hot and cold; the material with the higher temperature is said to be hotter. ... The kelvin (symbol: K) is the SI unit of temperature, and is one of the seven SI base units. ... To help compare different orders of magnitude this page lists temperatures between 10 kelvins and 100 kelvins. ... Atmosphere is the general name for a layer of gases that may surround a material body of sufficient mass. ... diurnal (daily) rhythm of air pressure in northern Germany (black curve is air pressure) Atmospheric pressure is the pressure above any area in the Earths atmosphere caused by the weight of air. ... The pascal (symbol Pa) is the SI unit of pressure. ... General Name, Symbol, Number Hydrogen, H, 1 Chemical series nonmetals Group, Period, Block 1 (IA), 1, s Density, Hardness 0. ... General Name, Symbol, Number Helium, He, 2 Atomic mass 4. ... The simplest hydrocarbon, methane, is a gas with a chemical formula of CH4. ... Ammonia is a chemical compound with the formula NH3. ... Ethane is a chemical compound with chemical formula C2H6. ... The chemical compound acetylene, also called ethyne, was discovered in 1836 by Edmund Davy, in England; its chemical formula is C2H2 and its structure is: Acetylene is a colorless and extremely flammable gas at standard temperature and pressure, with a melting point of -80. ... Carbon monoxide, chemical formula CO, is a colourless, odourless, flammable and highly toxic gas. ... For an alternative meaning for H2S, see H2S radar. ... A planet (from the Greek πλανήτης, planētēs which means wanderer or more forcefully vagrant, tramp) is an object in orbit around a star that is not a star in its own right. ... A sun is the star at the center of a solar system. ... A gas giant is a large planet that is not composed mostly of rock or other solid matter. ... Greek mythology comprises the collected legends of Greek gods, goddesses, heroes, and heroines, originally created and spread within an oral-poetic tradition. ... Ouranos is the Greek name of the sky, latinized as Uranus. ... Mosaic of the planets of the solar system, excluding Pluto, and including Earths Moon. ... Roman mythology can be considered as two parts. ... In computing, Unicode is the international standard whose goal is to provide the means to encode the text of every document people want to store in computers. ... Astronomical symbol for the planet Uranus. ...

Physical characteristics

Composition

Uranus is composed primarily of rock and various ices, with only about 15% hydrogen and a little helium (in contrast to Jupiter and Saturn which are mostly hydrogen). Uranus (like Neptune) is in many ways similar to the cores of Jupiter and Saturn minus the massive liquid metallic hydrogen envelope. It appears that Uranus does not have a rocky core like Jupiter and Saturn but rather that its material is more or less uniformly distributed. Uranus' cyan color is due to the absorption of red light by atmospheric methane. General Name, Symbol, Number Hydrogen, H, 1 Chemical series nonmetals Group, Period, Block 1 (IA), 1, s Density, Hardness 0. ... General Name, Symbol, Number Helium, He, 2 Atomic mass 4. ... Atmospheric characteristics Atmospheric pressure 100-300 kPa Hydrogen >84% Helium >12% Methane 2% Ammonia 0. ... Atmospheric characteristics Atmospheric pressure 70 kPa Hydrogen ~86% Helium ~14% Methane 0. ... Atmospheric characteristics Atmospheric pressure 140 kPa Hydrogen >93% Helium >5% Methane 0. ... Metallic hydrogen results when hydrogen is sufficiently compressed and undergoes a phase change, and it is an example of degenerate matter. ... Sedimentary, volcanic, plutonic, metamorphic rock types of North America. ... Cyan is a pure spectral color, but the same hue can also be generated by mixing equal amounts of green and blue light. ... Red is a color at the lowest frequencies of light discernible by the human eye. ... The simplest hydrocarbon, methane, is a gas with a chemical formula of CH4. ...

Axial tilt

One of the most distinctive features of Uranus is its axial tilt of almost ninety degrees. Consequently, for part of its orbit one pole faces the Sun continually whilst the other pole faces away. At the other side of Uranus' orbit the orientation of the poles towards the Sun is reversed. Between these two extremes of its orbit the Sun rises and sets around the equator normally. A sun is the star at the center of a solar system. ...

At the time of Voyager 2's passage in 1986, Uranus' south pole was pointed almost directly at the Sun. Note that the labelling of this pole as "south" is actually in some dispute. Uranus can either be described as having an axial tilt of slightly more than 90°, or it can be described as having an axial tilt of slightly less than 90° and rotating in a retrograde direction; these two descriptions are exactly equivalent as physical descriptions of the planet but result in different definitions of which pole is the North Pole and which is the South Pole. The Voyager 2 spacecraft was launched in 1977, originally planned as Mariner 12 of the Mariner program. ... 1986 is a common year starting on Wednesday of the Gregorian calendar. ... This article is about retrograde motion. ... A North Pole is the northernmost point on any planet. ... Location of the South Pole in the Antarctic continent. ...

One result of this odd orientation is that the polar regions of Uranus receive a greater energy input from the Sun than its equatorial regions. Uranus is nevertheless hotter at its equator than at its poles, although the underlying mechanism which causes this is unknown. The reason for Uranus' extreme axial tilt is also not known. It is speculated that perhaps during the formation of the planet it collided with an enormous protoplanet, resulting in the skewed orientation.

It appears that Uranus' extreme axial tilt also results in extreme seasonal variations in its weather. During the Voyager 2 flyby, Uranus' banded cloud patterns were extremely bland and faint. Recent Hubble Space Telescope observations, however, show a more strongly banded appearance now that the Sun is approaching Uranus' equator. By 2007 the Sun will be directly over Uranus' equator. The Hubble Space Telescope is one of the most important telescopes in the history of astronomy. ... 2007 is a common year starting on Monday of the Gregorian calendar. ...

Magnetic Field

Uranus' magnetic field is odd in that it is not centered on the center of the planet and is tilted almost 60° with respect to the axis of rotation. It is probably generated by motion at relatively shallow depths within Uranus. Neptune has a similarly displaced magnetic field, suggesting that this is not necessarily a result of Uranus' axial tilt. The magnetotail is twisted by the planet's rotation into a long corkscrew shape behind the planet. The magnetic field's source is unknown; the electrically conductive, super-pressurized ocean of water and ammonia once thought to lie between the core and the atmosphere now appears to be nonexistent. Current flowing through a wire produces a magnetic field (M) around the wire. ... A magnetosphere is the region around an astronomical object, in which phenomena are dominated by its magnetic field. ...

Discovery and naming of Uranus

Uranus was the first planet to be discovered that was not known in ancient times, although it had been observed on many previous occasions but was always dismissed as simply another star. The earliest recorded sighting was in 1690 when John Flamsteed catalogued it as 34 Tauri. Flamsteed observed Uranus twice again, in 1712 and 1715. Bradley observed it in 1748, 1750 and 1753; Mayer in 1756. Lemonnier observed it four times in 1750, twice in 1768, six times in 1769, and one last time in 1771. He was a victim of his own disorderliness: one of his observations was found consigned on a paper bag used to store hair powder! Events Giovanni Domenico Cassini observes differential rotation within Jupiters atmosphere. ... John Flamsteed. ... Taurus (♉) is one of the constellations of the zodiac, and its name is Latin for Bull. ... Events Treaty of Aargau signed between Catholic and Protestants. ... Events September 1 - King Louis XIV of France dies after a reign of 72 years, leaving the throne of his exhausted and indebted country to his great-grandson Louis XV. Regent for the new, five years old monarch is Philippe dOrléans, nephew of Louis XIV. September - First of the... Bradley may be the surname of these and other notable persons: Bill Bradley, basketball player who became a Senator from New Jersey Bill Bradley, early 20th-century third baseman in Major League Baseball Henry Bradley, editor of the Oxford English Dictionary James Bradley, astronomer Marion Zimmer Bradley, science fiction author... Events April 24 - A congress assembles at Aix-la-Chapelle with the intent to conclude the struggle known as the War of Austrian Succession - at October 18 - The Treaty of Aix-la-Chapelle is signed to end the war Adam Smith begins to deliver public lectures in Edinburgh Building of... Events March 2 - Small earthquake in London April 4 - Small earthquake in Warrington, England August 23 - Small earthquake in Spalding, England September 30 - Small earthquake in Northampton, England November 16 – Westminster Bridge officially opened Jonas Hanway is the first Englishman to use an umbrella James Gray reveals her sex to... 1753 was a common year starting on Monday (see link for calendar). ... Mayer is a city located in Carver County, Minnesota. ... 1756 was a leap year starting on Thursday (see link for calendar). ... Pierre Charles Le Monnier (November 23, 1715 – May 31, 1799) was a French astronomer. ... Events March 2 - Small earthquake in London April 4 - Small earthquake in Warrington, England August 23 - Small earthquake in Spalding, England September 30 - Small earthquake in Northampton, England November 16 – Westminster Bridge officially opened Jonas Hanway is the first Englishman to use an umbrella James Gray reveals her sex to... 1768 was a leap year starting on Friday (see link for calendar). ... 1769 was a common year starting on Sunday (see link for calendar). ... 1771 was a common year starting on Tuesday (see link for calendar). ...

Sir William Herschel discovered the planet on March 13, 1781, but reported it on April 26, 1781 as a "comet": Account of a Comet, By Mr. Herschel, F. R. S.; Communicated by Dr. Watson, Jun. of Bath, F. R. S., Philosophical Transactions of the Royal Society of London, Volume 71, pp. 492-501. Sir Wilhelm Friedrich Herschel (Hanover, November 15, 1738 – August 25, 1822 Slough, then in Buckinghamshire now in Berkshire) was a German-born British astronomer and composer who became famous for discovering the planet Uranus, and made many other astronomical discoveries. ... March 13 is the 72nd day of the year in the Gregorian calendar (73rd in leap years). ... 1781 was a common year starting on Monday (see link for calendar). ... April 26 is the 116th day of the year in the Gregorian Calendar (117th in leap years). ... 1781 was a common year starting on Monday (see link for calendar). ... Comet Hale-Bopp, showing a white dust tail and blue gas tail (February 1997) A comet is a small astronomical object similar to an asteroid but composed largely of ice. ...

Herschel originally named it Georgium Sidus (George's Star) in honour of King George III of England. When it was pointed out that sidus means star and not planet, he rebaptised it the Georgian Planet. In any case, this name was not acceptable outside of Britain. Lalande proposed in 1784 to name it Herschel, at the same time that he created the planet's symbol ("a globe surmounted by your initial"); his proposal was readily adopted by French astronomers. Prosperin, of Uppsala, proposed the names Astraea, Cybele, and Neptune (now borne by two asteroids and a planet). Lexell, of St. Petersburg, compromised with George III's Neptune and Great-Britain's Neptune. Bernoulli, from Berlin, suggested Hypercronius and Transaturnis. Lichtenberg, from Göttingen, chimed in with Austräa, a goddess mentioned by Ovid (but who is traditionally associated with Virgo). The name Minerva was also proposed [1] (http://vesuvius.jsc.nasa.gov/er/seh/hersc.html). Finally, Bode, as editor of the Berliner Astronomisches Jahrbuch, opted for Uranus, after the Greek god; Hell followed suit by using it in the first ephemeris, published in Vienna. Examination of earliest issues of Monthly Notices of the Royal Astronomical Society from 1827 shows that the name Uranus was already the most common name used even by British astronomers by then, and probably earlier. The name Georgium Sidus or "the Georgian" were still used infrequently (by the British alone) thereafter. The final holdout was HM Nautical Almanac Office, which did not switch to Uranus until 1850. George III (George William Frederick) (4 June 1738 – 29 January 1820) was King of Great Britain, and King of Ireland from 25 October 1760 until 1 January 1801, and thereafter King of the United Kingdom of Great Britain and Ireland until his death. ... Royal motto: Dieu et mon droit (French: God and my right) Englands location within the UK Official language English de facto Capital London de facto Largest city London Area - Total Ranked 1st UK 130,395 km² Population - Total (2001) - Density Ranked 1st UK 49,138,831 377/km² Religion... Joseph Jérôme Lefrançais de Lalande ( July 11, 1732 – April 4, 1807) was a French astronomer. ... 1784 was a leap year starting on Thursday (see link for calendar). ... Erik Prosperin (1739–1803) was a Swedish astronomer. ... This article is about the modern city of Uppsala. ... An asteroid is a small, solid object in our Solar System, orbiting the Sun. ... Anders Johan Lexell (December 24, 1740 – December 11, 1784 (Julian calendar: November 30)) was a Swedish_Russian astronomer and mathematician. ... Saint Petersburg (Russian: Санкт-Петербу́рг, English transliteration: Sankt-Peterburg), colloquially known as Питер (transliterated Piter), formerly known as Leningrad (Ленингра́д, 1924–1991) and Petrograd (Петрогра́д, 1914–1924), is a city located in Northwestern Russia on the delta of the river Neva at the east end of the Gulf of Finland... Daniel Bernoulli Daniel Bernoulli (Groningen, February 9, 1700 – Basel, March 17, 1782) was a Dutch-born mathematician who spent much of his life in Basel, Switzerland. ... Berlin (pronounced: , German ) is the capital of Germany and its largest city, with 3,426,000 inhabitants (as of January 2005); down from 4. ... Georg Christoph Lichtenberg. ... Map of Germany showing Göttingen 1 External links Coat of Arms University of Göttingen Top: The old Auditorium Maximum (1862-65) Bottom: New library building Göttingen is a city in Lower Saxony, Germany. ... Engraved frontispiece of George Sandyss 1632 London edition of Publius Ovidius Naso, (March 20, 43 BC – AD 17) Roman poet known to the English-speaking world as Ovid, wrote on topics of love, abandoned women, and mythological transformations. ... See VIRGO (physics) for a French-Italian project in physics. ... Minerva was a Roman goddess of crafts and wisdom. ... 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. ... Greek mythology comprises the collected legends of Greek gods, goddesses, heroes, and heroines, originally created and spread within an oral-poetic tradition. ... Maximilian Hell or Maximilian Höll (May 15, 1720 – April 14, 1792) was an astronomer, and also a Jesuit and an ordained priest. ... 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, and the planets in the sky at... Vienna (German: Wien [viːn]) is the capital of Austria, and also one of Austrias nine federal states (Bundesland Wien). ... 1827 was a common year starting on Monday (see link for calendar). ... The HM Nautical Almanac Office (HMNAO), now part of the Rutherford Appleton Laboratory, near Abingdon in Oxfordshire, was established in 1832 on the site of the Royal Greenwich Observatory, where the Nautical Almanac had been published since 1767. ... 1850 was a common year starting on Tuesday (see link for calendar). ...

Exploration of Uranus

NASA's Voyager 2 is the only spacecraft to have visited the planet. Launched in 1977, Voyager made its closest approach to Uranus on January 24, 1986 before continuing on its journey to Neptune. SUCK MY WENIS!!! NASA IS A ROCKET SHIP PROGRAM FOR TODDLERS ... The Voyager 2 spacecraft was launched in 1977, originally planned as Mariner 12 of the Mariner program. ... 1977 was a common year starting on Saturday (the link is to a full 1977 calendar). ... January 24 is the 24th day of the year in the Gregorian Calendar. ... 1986 is a common year starting on Wednesday of the Gregorian calendar. ... Atmospheric characteristics Atmospheric pressure 100-300 kPa Hydrogen >84% Helium >12% Methane 2% Ammonia 0. ...

Visibility

The brightness of Uranus is between magnitude +5.5 and +6.0, so it can be seen with the naked eye as a faint star under dark sky conditions. It can be easily found with binoculars. From Earth it has a diameter of 4". Even in large telescopes no details can be seen on its disc.

Appearance

The rings of Uranus

Main article: Rings of Uranus This is a list of the named planetary rings of Uranus. ...

Uranus has a faint planetary ring system, composed of dark particulate matter up to 10 metres in diameter. This ring system was discovered in March 1977 by James L. Elliot, Edward W. Dunham, and Douglas J. Mink, using the Kuiper Airborne Observatory. The discovery was serendipitous; they planned to use the occultation of a star by Uranus to study the planet's atmosphere, but when they analysed their observations they found that the star had disappeared briefly from view five times both before and after it disappeared behind the planet. They concluded that there must be a ring system around the planet; it was directly detected when the Voyager 2 space probe passed Uranus in 1986. A planetary ring is a ring of dust and other small particles orbiting around a planet in a flat disc-shaped region. ... 1977 was a common year starting on Saturday (the link is to a full 1977 calendar). ... Categories: Astronomy stubs | Astronomical observatories ... 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. ... Atmosphere may refer to: a celestial body atmosphere, e. ... The Voyager 2 spacecraft was launched in 1977, originally planned as Mariner 12 of the Mariner program. ... 1986 is a common year starting on Wednesday of the Gregorian calendar. ...

The moons of Uranus

Uranus has 27 known moons. The five main satellites are Miranda, Ariel, Umbriel, Titania and Oberon. The common noun moon (not capitalized) is used to mean any natural satellite of the other planets. ... Miranda (mi-ran-da) is the smallest and innermost of Uranus major moons. ... Atmospheric pressure 0 kPa Ariel (AIR ee el) is a moon of Uranus discovered in 1851 by William Lassell. ... Click for full description. ... Titania should not be confused with Titan, a moon of Saturn. ... Atmospheric pressure 0 kPa Oberon (O ber on) is the outermost of the major moons of the planet Uranus. ...

For a timeline of discovery dates, see Timeline of natural satellites. Timeline of natural satellites in the Solar system by decade of discovery For comparison, discovery dates of Uranus, Neptune and Pluto are also included, as well as the first six asteroids. ...

Uranus in fiction

North American DVD release of the 1979-81 Buck Rogers in the 25th Century TV series. ... The Montréal Biodome is a zoo divided into four environment zones. ... A humanoid robot playing the trumpet In practical usage, a robot is a mechanical device which performs automated tasks, either according to direct human supervision, a pre-defined program or, a set of general guidelines using artificial intelligence techniques. ... Futurama was an animated American cartoon series created by Matt Groening (creator of The Simpsons) and David X. Cohen (also a writer for The Simpsons). ...

Uranus in astrology