Neptune is the eighth planet from the sun and the outermost gas giant in our solar system. It is fourth largest by diameter and third largest by mass, but it is the smallest of the gas giants. Due to Pluto's eccentric orbit, Neptune is sometimes the furthest planet from the Sun. Neptune is the smallest of the four gas giants. It is slightly smaller than Uranus, but more massive. Urbain Le Verrier. ... For other people named John Adams, see John Adams (disambiguation). ... 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. ... September 23 is the 266th day of the year (267th in leap years). ... 1846 was a common year starting on Thursday (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 term semi-major axis (also semimajor axis) is used to describe the dimensions of ellipses and hyperbolas. ... To help compare different distances this page lists lengths starting at 1012 m (1000 million km). ... 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 is the basic unit of length in the International System of Units (SI: Système International dUnités). ... (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. ... Moons of solar system scaled to Earths Moon 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. ... For the authentication, authorisation, and accounting protocol, see DIAMETER. 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... 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. ... It has been suggested that Law of universal gravitation be merged into this article or section. ... The bar is a measurement unit of pressure, equal to 1,000,000 dynes per square centimetre (baryes), or 100,000 newtons per square metre (pascals). ... 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... 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. ... 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. ... Surface pressure is the atmospheric pressure at a point of Earths surface. ... The pascal (symbol Pa) is the SI unit of pressure. ... General Name, Symbol, Number hydrogen, H, 1 Chemical series nonmetals Group, Period, Block 1, 1, s Appearance colorless Atomic mass 1. ... General Name, Symbol, Number helium, He, 2 Chemical series noble gases Group, Period, Block 18, 1, s Appearance colorless Atomic mass 4. ... The simplest hydrocarbon, methane, is a gas with a chemical formula of CH4. ... Deuterium, also called heavy hydrogen, is a stable isotope of hydrogen with a natural abundance of one atom in 6500 of hydrogen. ... Parts per million (ppm) is a measure of concentration that is used where low levels of concentration are significant. ... Ethane is a chemical compound with chemical formula C2H6. ... A planet (from the Greek πλανήτης, planÄ“tÄ“s 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. ... The Sun is the star at the centre of our Solar system. ... Gas giant - Wikipedia, the free encyclopedia /**/ @import /skins-1. ... Presentation of the Solar system (not to scale). ... A gas giant is a large planet that is not composed mostly of rock or other solid matter. ... Atmospheric characteristics Atmospheric pressure 0. ... (This page refers to eccitricity in astrodynamics. ... The Sun is the star at the centre of our Solar system. ...

Faint dark rings have been detected around the blue planet, but are less substantial than those of Saturn. When these rings were discovered, it was thought that they might not be complete, but this was disproved by Voyager 2. Neptune also has 2,000 km/h winds of hydrogen, helium, and methane that gives it its blue appearance. In its southern hemisphere, it has a Great Dark Spot comparable to the Great Red Spot on Jupiter. It possesses eight confirmed moons and five awaiting confirmation, the largest of which, Triton, is known for its subzero temperatures and methane production. The Voyager 2 spacecraft was launched in 1977, originally planned as Mariner 12 of the Mariner program. ... The Great Dark Spot as seen from Voyager 2 The Great Dark Spot was a dark spot on Neptune similar to Jupiters Great Red Spot. ... The Great Red Spot as seen from Voyager 1 The Great Red Spot is an anticyclonic storm on the planet Jupiter, 22° south of the equator, which has lasted at least 300 years. ...

Neptune is named after the Roman god of the sea. Its symbol is a stylised representation of the god's trident (Unicode: ♆). Discovered on September 23, 1846, Neptune has been visited by only one spacecraft, Voyager 2, which flew by the planet on August 25, 1989. This article is about the Greek god. ... Poseidon sculpture holding a trident A trident (from Latin tridens, tridentis, from tri, three, dens, tooth, dentes, teeth) is a three pronged staff. ... In computing, Unicode provides an international standard which has the goal of providing the means to encode the text of every document people want to store on computers. ... September 23 is the 266th day of the year (267th in leap years). ... 1846 was a common year starting on Thursday (see link for calendar). ... The Voyager 2 spacecraft was launched in 1977, originally planned as Mariner 12 of the Mariner program. ... August 25 is the 237th day of the year in the Gregorian Calendar (238th in leap years), with 128 days remaining. ... 1989 is a common year starting on Sunday of the Gregorian calendar. ...

Physical characteristics

Orbiting so far from the sun, Neptune receives very little heat. Its surface temperature is −218 °C (55 K). However, the planet seems to have an internal source of heat. It is thought that this may be leftover heat generated by infalling matter during the planet's birth, now slowly radiating away into space. Neptune's atmosphere has the highest wind speeds in the solar system, up to 2000 km/h, thought to be powered by this flow of internal heat. The accretion theory, in astrophysics, is a scientific theory of the formation of our Solar system. ... Atmosphere is the general name for a layer of gases that may surround a material body of sufficient mass. ...

The internal structure resembles that of Uranus. There is likely to be a core consisting of (molten) rock and metal, surrounded by a mixture of rock, water, ammonia, and methane. The atmosphere, extending perhaps 10 to 20 percent of the way towards the centre, is mostly hydrogen and helium at high altitudes, but has increasing concentrations of methane, ammonia, and water as it approaches and finally blends into the liquid interior. Comparing its rotational speed to its degree of oblateness indicates that it has its mass less concentrated towards the centre than does Uranus. Atmospheric characteristics Atmospheric pressure 120 kPa Hydrogen 83% Helium 15% Methane 1. ... The planetary core consists of the innermost layers of a planet. ...

Neptune also resembles Uranus in its magnetosphere, with a magnetic field strongly tilted relative to its rotational axis at 47° and offset at least 0.55 radii (about 13,500 kilometres) from the planet's physical centre. Comparing the magnetic fields of the two planets, scientists think the extreme orientation may be characteristic of flows in the interior of the planet and not the result of Uranus' sideways orientation. A magnetosphere is the region around an astronomical object, in which phenomena are dominated by its magnetic field. ... Current flowing through a wire produces a magnetic field (M) around the wire. ... Rotation is the movement of a body in such a way that the distance between a certain fixed point and any given point of that body remains constant. ...

One difference between Neptune and Uranus is the level of meteorological activity. Uranus is visually quite bland, while Neptune's high winds come with notable weather phenomena. The Great Dark Spot, an Earth-sized dark marking resembling the Great Red Spot of Jupiter, disappeared in 1994 but another reappeared later. Unique among the gas giants is the presence of high clouds casting shadows on the opaque cloud deck below. The Great Dark Spot as seen from Voyager 2 The Great Dark Spot was a dark spot on Neptune similar to Jupiters Great Red Spot. ... The Great Red Spot as seen from Voyager 1 The Great Red Spot is an anticyclonic storm on the planet Jupiter, 22° south of the equator, which has lasted at least 300 years. ... 1994 was a common year starting on Saturday of the Gregorian calendar, and was designated the International year of the Family. ...

Discovery of Neptune

Galileo's astronomical drawings show that he had first observed Neptune on December 27, 1612, and again on January 27, 1613; on both occasions Galileo mistook Neptune for a fixed star when it appeared very close (in conjunction) to Jupiter in the night sky. Believing it to be a fixed star, he cannot be credited with its discovery. At the time Galileo first observed Neptune on December 28, 1612, it was stationary in the sky because it had just turned retrograde that very day; because it was stationary in the sky and only beginning the planet's yearly retrograde cycle, its motion was far too slight to be noticed with the naked eye, even with the help that a telescope provided. Had Neptune been moving at its regular/average speed when Galileo first observed it in 1612 and 1613, he would have most likely realised that it was a planet and not a fixed star because of Neptune's relatively rapid normal motion along the ecliptic compared to the extremely slow motion of any random fixed star found in the night sky. Galileo Galilei (Pisa, February 15, 1564 – Arcetri, January 8, 1642), was a Tuscan astronomer, philosopher, and physicist who is closely associated with the scientific revolution. ... December 27 is the 361st day of the year in the Gregorian Calendar. ... Events January 20 - Mathias becomes Holy Roman Emperor. ... January 27 - Wikipedia, the free encyclopedia /**/ @import /skins-1. ... Events January - Galileo observes Neptune, but mistakes it for a star and so is not credited with its discovery. ... A fixed star is a celestial object that does not seem to move (in comparison to the other stars of the night sky). ... Atmospheric characteristics Atmospheric pressure 70 kPa Hydrogen ~86% Helium ~14% Methane 0. ... December 28 is the 362nd day of the year (363rd in leap years) in the Gregorian Calendar, with 3 days remaining. ... Events January 20 - Mathias becomes Holy Roman Emperor. ... This article is about retrograde motion. ... 50 cm refracting telescope at Nice Observatory. ... The plane of the Ecliptic is well seen in this picture from the 1994 lunar prospecting Clementine spacecraft. ... Amateur astronomy, often called back yard astronomy, is a hobby whose participants enjoy observing celestial objects. ...

In 1821, Alexis Bouvard published astronomical tables of the orbit of Uranus. Subsequent observations revealed substantial deviations from the tables, leading Bouvard to hypothesise some perturbing body. In 1843, John Couch Adams calculated the orbit of an eighth planet that would account for Uranus' motion. He sent his calculations to Sir George Airy, who asked Adams for a clarification; Adams began to draft a reply but never sent it. 1821 was a common year starting on Monday (see link for calendar). ... Alexis Bouvard (June 27, 1767 - June 7, 1843) was a French astronomer, born in Contamines, France. ... 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. ... Atmospheric characteristics Atmospheric pressure 120 kPa Hydrogen 83% Helium 15% Methane 1. ... 1843 was a common year starting on Sunday (see link for calendar). ... For other people named John Adams, see John Adams (disambiguation). ... 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. ... Atmospheric characteristics Atmospheric pressure 120 kPa Hydrogen 83% Helium 15% Methane 1. ... George Biddell Airy Sir George Biddell Airy (July 27, 1801 – January 2, 1892) was British Astronomer Royal from 1835 to 1881. ...

In 1846, Urbain Le Verrier, independently of Adams, produced his own calculations but also experienced difficulties in encouraging any enthusiasm in his compatriots. However, in the same year, John Herschel started to champion the mathematical approach and persuaded James Challis to search for the planet. 1846 was a common year starting on Thursday (see link for calendar). ... Urbain Le Verrier. ... John Herschel John Frederick William Herschel (7 March 1792 – 11 May 1871) was an English mathematician and astronomer. ... James Challis (December 12, 1803 – December 3, 1882) was a British clergyman and astronomer. ...

After much procrastination, Challis began his reluctant search in July 1846. However, in the mean time, Le Verrier had convinced Johann Gottfried Galle to search for the planet. Though still a student at the Berlin Observatory, Heinrich d'Arrest suggested that a recently drawn chart of the sky, in the region of Le Verrier's predicted location, could be compared with the current sky to seek the displacement characteristic of a planet, as opposed to a stationary star. Neptune was discovered that very night, September 23, 1846, within 1° of where Le Verrier had predicted it to be, and about 10° from Adams' prediction. Challis later realised that he had observed the planet twice in August, failing to identify it owing to his casual approach to the work. July is the seventh month of the year in the Gregorian Calendar and one of seven Gregorian months with the length of 31 days. ... 1846 was a common year starting on Thursday (see link for calendar). ... Urbain Le Verrier. ... 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. ... Heinrich Louis dArrest (July 13, 1822 – June 14, 1875) was a Prussian astronomer, born in Berlin. ... A planet (from the Greek πλανήτης, planÄ“tÄ“s 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. ... The Pleiades star cluster A star is any massive gaseous body in outer space. ... September 23 is the 266th day of the year (267th in leap years). ... 1846 was a common year starting on Thursday (see link for calendar). ...

In the aftermath of the discovery, there was much nationalistic rivalry between the French and the British over who had priority and who should get credit for the discovery. Eventually an international consensus emerged that both Le Verrier and Adams jointly deserved credit. However, the issue is now being re-evaluated by historians with the rediscovery in 1998 of the "Neptune papers" (historical documents from the Royal Greenwich Observatory), which had apparently been misappropriated by astronomer Olin Eggen for nearly three decades and were not rediscovered (in his possession) until immediately after his death. After reviewing the documents, some historians now suggest that Adams did not in fact deserve equal credit with Le Verrier. [2] 1998 is a common year starting on Thursday of the Gregorian calendar, and was designated the International Year of the Ocean. ... 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. ... Olin Jeuck Eggen (July 9, 1919 – October 2, 1998) was an American astronomer. ...

Naming of Neptune

Shortly after its discovery, Neptune was referred to simply as "the planet exterior to Uranus" or as "Le Verrier's planet". The first suggestion for a name came from Galle. He proposed the name Janus. In England, Challis put forth the name Oceanus, particularly appropriate for a seafaring people. In France, Arago suggested that the new planet be called Leverrier, a suggestion which was met with stiff resistance outside France. French almanacs promptly reintroduced the name Herschel for Uranus and Leverrier for the new planet. Janus may refer to Janus, the two-faced Roman god of gates, doors, beginnings, endings and doorways. ... Oceanus or Okeanos refers to the ocean, which the Greeks and Romans regarded as a river circling the world. ... François Jean Dominique Arago (February 26, 1786 – October 2, 1853) was a French mathematician, physicist, astronomer, and politician. ...

Meanwhile, on separate and independent occasions, Adams suggested altering the name Georgian to Uranus, while Leverrier (through the Board of Longitude) suggested Neptune for the new planet. Struve came out in favour of that name on December 29, 1846, to the Saint Petersburg Academy of Sciences [3]. Soon Neptune became internationally accepted nomenclature. In Roman mythology Neptune was the god of the sea, identified with the Greek Poseidon. The demand for a mythological name seemed to be in keeping with the nomenclature of the other planets, all of which, except Uranus, were named in antiquity. Friedrich Georg Wilhelm von Struve Friedrich Georg Wilhelm von Struve (April 15, 1793 – November 23, 1864 (Julian calendar: November 11)) was a German-Russian astronomer. ... December 29 is the 363rd day of the year (364th in leap years) in the Gregorian Calendar, with 2 days remaining. ... 1846 was a common year starting on Thursday (see link for calendar). ... 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... Roman mythology can be considered as two parts. ... This article is about the Greek god. ... Andrea Doria as Neptune by Agnolo Bronzino: a potent allegory of Genoas hegemony in the Tyrrhenian Sea In Greek Mythology, Poseidon (Ποσειδῶν) was the god of the sea, known to the Romans as Neptune, and to the Etruscans as Nethuns. ...

Visibility from Earth

Neptune is never visible with the naked eye. With the use of a telescope it appears as a blue-green disk, similar in appearance to Uranus; the blue-green colour comes from the methane in its atmosphere.

The brightness of Neptune is between magnitudes +7.7 and +8.0, so a telescope or binoculars are required to observe it. It can be also photographed as a faint star with a normal camera and high-sensitivity film.

With an orbital period of 165 years, Neptune will soon return to the approximate position where Galle discovered it, on three different dates. These are April 11, 2009, when it will be in direct motion; July 17, 2009, when it will be in retrograde motion; and finally for the last time for the next 165 years, on February 7, 2010. April 11 is the 101st day of the year in the Gregorian calendar (102nd in leap years). ... 2009 is a common year starting on Thursday of the Gregorian calendar. ... This article is about retrograde motion. ... July 17 is the 198th day (199th in leap years) of the year in the Gregorian calendar, with 167 days remaining. ... 2009 is a common year starting on Thursday of the Gregorian calendar. ... This article is about retrograde motion. ... February 7 is the 38th day of the year in the Gregorian Calendar. ... 2010 is a common year starting on Friday of the Gregorian calendar. ...

Appearance

May 17 is the 137th day of the year in the Gregorian Calendar (138th in leap years). ... 2004 is a leap year starting on Thursday of the Gregorian calendar. ... August 6 is the 218th day of the year in the Gregorian Calendar (219th in leap years), with 147 days remaining. ... 2004 is a leap year starting on Thursday of the Gregorian calendar. ... October 24 is the 297th day of the year (298th in leap years) in the Gregorian Calendar, with 68 days remaining. ... 2004 is a leap year starting on Thursday of the Gregorian calendar. ... February 2 is the 33rd day of the year in the Gregorian Calendar. ... 2004 is a leap year starting on Thursday of the Gregorian calendar. ... May 20 is the 140th day of the year in the Gregorian Calendar (141st in leap years). ... 2005 is a common year starting on Saturday of the Gregorian calendar and is the current year. ... 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March 4 is the 63rd day of the year in the Gregorian Calendar (64th in leap years). ... 2018 is a Common year starting on Monday. ... June 22 is the 173rd day of the year (174th in leap years) in the Gregorian Calendar, with 192 days remaining. ... 2019 is a Common year starting on Tuesday. ... September 10 is the 253rd day of the year (254th in leap years). ... 2019 is a Common year starting on Tuesday. ... November 27 is the 331st day (332nd on leap years) of the year. ... 2019 is a Common year starting on Tuesday. ... March 7 is the 66th day of the year in the Gregorian Calendar (67th in Leap years). ... 2019 is a Common year starting on Tuesday. ... June 23 is the 174th day of the year (175th in leap years) in the Gregorian Calendar, with 191 days remaining. ... 2020 is a leap year starting on Wednesday. ... September 11 is the 254th day of the year (255th in leap years). ... 2020 is a leap year starting on Wednesday. ... 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The rings of Neptune

Main article: Rings of Neptune This is a list of the named rings and ring arcs of Neptune. ...

Neptune's rings

Neptune has a faint planetary ring system of unknown composition. The rings have a peculiar "clumpy" structure, the cause of which is not currently understood but which may be due to the gravitational interaction with small moons in orbit near them. Credit: Courtesy NASA/JPL-Caltech [1] http://photojournal. ... Credit: Courtesy NASA/JPL-Caltech [1] http://photojournal. ... A planetary ring is a ring of dust and other small particles orbiting around a planet in a flat disc-shaped region. ...

Evidence that the rings are incomplete first arose in the mid-1980s, when stellar occultation experiments were found to occasionally show an extra "blink" just before or after the planet occulted the star. Images by Voyager 2 in 1989 settled the issue, when the ring system was found to contain several faint rings, the outermost of which, Adams, contains three prominent arcs now named Liberté, Egalité, and Fraternité (Liberty, Equality, and Fraternity). The existence of arcs is very difficult to understand because the laws of motion would predict that arcs spread out into a uniform ring over very short timescales. // Events and trends The 1980s marked an abrupt shift towards more conservative lifestyles after the momentous cultural revolutions which took place in the 60s and 70s and the definition of the AIDS virus in 1981. ... 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 Voyager 2 spacecraft was launched in 1977, originally planned as Mariner 12 of the Mariner program. ... 1989 is a common year starting on Sunday of the Gregorian calendar. ...

The gravitational effects of Galatea, a moon just inward from the ring, are now believed to confine the arcs. Several other rings were detected by the Voyager cameras. In addition to the narrow Adams Ring 63,000 km from the centre of Neptune, the Leverrier Ring is at 53,000 km and the broader, fainter Galle Ring is at 42,000 km. A faint outward extension to the Leverrier Ring has been named Lassell; it is bounded at its outer edge by the Arago Ring at 57,000 km. [4] Galatea (GAL a TAY a) is the fourth known moon of Neptune, named after the Nereid of Greek legend. ... For other people named John Adams, see John Adams (disambiguation). ... Urbain Le Verrier. ... 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. ... William Lassell (June 18, 1799 – October 5, 1880) was a British astronomer. ... François Jean Dominique Arago (February 26, 1786 – October 2, 1853) was a French mathematician, physicist, astronomer, and politician. ...

New Earth-based observations announced in 2005 appeared to show that Neptune's rings are much more unstable than previously thought. In particular, it seems that the Liberté ring might disappear in as little as one century. The new observations appear to throw our understanding of Neptune's rings into considerable confusion. [5] 2005 is a common year starting on Saturday of the Gregorian calendar and is the current year. ...

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. ... Urbain Le Verrier. ... William Lassell (June 18, 1799 – October 5, 1880) was a British astronomer. ... François Jean Dominique Arago (February 26, 1786 – October 2, 1853) was a French mathematician, physicist, astronomer, and politician. ... For other people named John Adams, see John Adams (disambiguation). ...

The moons of Neptune

Main article: Neptune's natural satellites Neptune has 13 known moons. ...

Neptune has 13 known moons. The largest by far is Triton, discovered by William Lassell just 17 days after the discovery of Neptune itself. Unlike all other large planetary moons, it has a retrograde and synchronous orbit. Triton is the coldest object that has been measured in our solar system, and it is slowly spiraling toward Neptune. Neptune's second satellite, Nereid, has one of the most eccentric orbits of any satellite in the solar system. Moons of solar system scaled to Earths Moon The common noun moon (not capitalized) is used to mean any natural satellite of the other planets. ... Triton (trye-tun, Greek Τρίτων) is the planet Neptunes largest moon, discovered by William Lassell on 1846-10-10, just 17 days after the planet itself was discovered. ... William Lassell (June 18, 1799 – October 5, 1880) was a British astronomer. ... This article is about retrograde motion. ... A synchronous orbit is an orbit in which an orbiting body (usually a satellite) has a period equal to the average rotational period of the body being orbited (usually a planet), and in the same direction of rotation as that body. ... Voyager 2 view of Nereid. ...

From July to September 1989, Voyager 2 discovered six new Neptunian moons. Of these, the irregularly shaped Proteus is notable for having as large of a body of its density can be without being pulled into a spherical shape by its own gravity. Neptune's first four moons, Naiad (moon), Thalassa (moon), Despina (moon), and Galatea (moon) orbit close enough to be within Neptune's rings. The next farthest out, Larissa (moon) was originally discovered in 1981 when it had blocked a star. This was attributed to ring arcs, but when Voyager 2 observed Neptune in 1989, it was found to have been caused by the moon. July is the seventh month of the year in the Gregorian Calendar and one of seven Gregorian months with the length of 31 days. ... September is the ninth month of the year in the Gregorian Calendar and one of four Gregorian months with the length of 30 days. ... 1989 is a common year starting on Sunday of the Gregorian calendar. ... The Voyager 2 spacecraft was launched in 1977, originally planned as Mariner 12 of the Mariner program. ... Neptunes satellite 1989N1, obtained by Voyager 2 on August 25, 1989 from a range of 146,000 kilometers (NASA) Proteus (PRO tay us) is one of Neptunes moons. ... A moon of Neptune, Naiad (NYE ad [UK, US] or NAY ad [US]) is named after the Naiads of Greek legend. ... Thalassa (thal ASS a) is the second moon of Neptune. ... Despina (dess PEE na or dess PYE na) is the third known moon of Neptune. ... Galatea (GAL a TAY a) is the fourth known moon of Neptune, named after the Nereid of Greek legend. ... Larissa (la RISS a) is the fifth of Neptunes known moons. ...

Five new irregular moons were announced in 2004.They were discovered in 2002 and 2003. (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. ...

Neptune in fiction and film

• In Olaf Stapledon's epic novel Last and First Men, Neptune is the final home of the highly evolved human race.
• Neptune is the setting of the sci-fi/horror film Event Horizon, although it is used purely as a backdrop.
• Neptune is the intended destination of the mining ship Red Dwarf in the books based on the BBC sitcom of that name, but an accident on board sends it into deep space instead.
• In the animated TV series Futurama, Neptunians are a purple-skinned, four-armed race of humanoids that coexist peacefully with humans across the Solar System. Robot Santa's base is also located on Neptune.

William Olaf Stapledon (1886-1950) was a British philosopher and author of several influential works of science fiction. ... Last and First Men is a science fiction novel written in 1930 by the British author Olaf Stapledon. ... Event Horizon is a 1997 science fiction and horror film. ... This article describes the British science fiction comedy television series. ... The British Broadcasting Corporation (BBC) was formed in 1927 by means of a royal charter. ... Futurama is an animated American cartoon series created by Matt Groening (creator of The Simpsons) and David X. Cohen (also a writer for The Simpsons). ...

See also

• Planets in astrology - Neptune

In traditional Western astrology, the planets have the significances listed below. ...

References

• Airy, G. B., "Account of some circumstances historically connected with the discovery of the planet exterior to Uranus", Monthly Notices of the Royal Astronomical Society, Vol. 7, pp. 121-144, November 13, 1846
• Challis, J., Rev., "Account of observations at the Cambridge observatory for detecting the planet exterior to Uranus", Monthly Notices of the Royal Astronomical Society, Vol. 7, pp. 145-149, November 13, 1846
• Adams, J. C., "Explanation of the observed irregularities in the motion of Uranus, on the hypothesis of disturbance by a more distant planet", Monthly Notices of the Royal Astronomical Society, Vol. 7, p. 149, November 13, 1846
• Galle, "Account of the discovery of the planet of Le Verrier at Berlin", Monthly Notices of the Royal Astronomical Society, Vol. 7, p. 153, November 13, 1846
• Neptune: The Planet, Rings, and Satellites, Ellis D. Miner et Randii R. Wessen, 2002. ISBN 1-852-33216-6
• Neptune and Triton, Dale P. Cruikshank, 1995. ISBN 0-816-51525-5
• "The case of the pilfered planet - Did the British steal Neptune?", William Sheehan, Nicolas Kollerstrom and Craig B. Waff, Scientific American December 2004.

November 13 is the 317th day of the year (318th in leap years) in the Gregorian Calendar, with 48 days remaining. ... 1846 was a common year starting on Thursday (see link for calendar). ... November 13 is the 317th day of the year (318th in leap years) in the Gregorian Calendar, with 48 days remaining. ... 1846 was a common year starting on Thursday (see link for calendar). ... November 13 is the 317th day of the year (318th in leap years) in the Gregorian Calendar, with 48 days remaining. ... 1846 was a common year starting on Thursday (see link for calendar). ... November 13 is the 317th day of the year (318th in leap years) in the Gregorian Calendar, with 48 days remaining. ... 1846 was a common year starting on Thursday (see link for calendar). ...

External links

• NASA's Neptune fact sheet

A moon of Neptune, Naiad (NYE ad [UK, US] or NAY ad [US]) is named after the Naiads of Greek legend. ... Thalassa (thal ASS a) is the second moon of Neptune. ... Despina (dess PEE na or dess PYE na) is the third known moon of Neptune. ... Galatea (GAL a TAY a) is the fourth known moon of Neptune, named after the Nereid of Greek legend. ... Larissa (la RISS a) is the fifth of Neptunes known moons. ... Neptunes satellite 1989N1, obtained by Voyager 2 on August 25, 1989 from a range of 146,000 kilometers (NASA) Proteus (PRO tay us) is one of Neptunes moons. ... Triton (trye-tun, Greek Τρίτων) is the planet Neptunes largest moon, discovered by William Lassell on 1846-10-10, just 17 days after the planet itself was discovered. ... Voyager 2 view of Nereid. ... 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/2003 N 1 is a natural satellite of Neptune. ... S/2002 N 4 is a natural satellite of Neptune. ... Presentation of the Solar system (not to scale). ...