Neptune is the eighth and farthest planet from the Sun in the Solar System. It is the fourth-largest planet by diameter and the third-largest by mass. Neptune is 17 times the mass of Earth and is somewhat more massive than its near-twin Uranus, which is 15 times the mass of Earth but not as dense. On average, Neptune orbits the Sun at a distance of 30.1 AU, approximately 30 times the Earth–Sun distance. Named for the Roman god of the sea, its astronomical symbol is ♆, a stylised version of the god Neptune's trident.
Neptune was the first planet found by mathematical prediction rather than by empirical observation. Unexpected changes in the orbit of Uranus led Alexis Bouvard to deduce that its orbit was subject to gravitational perturbation by an unknown planet. Neptune was subsequently observed on 23 September 1846 by Johann Galle within a degree of the position predicted by Urbain Le Verrier, and its largest moon, Triton, was discovered shortly thereafter, though none of the planet's remaining 12 moons were located telescopically until the 20th century. Neptune has been visited by only one spacecraft, Voyager 2, which flew by the planet on 25 August 1989.
Neptune is similar in composition to Uranus, and both have compositions which differ from those of the larger gas giants, Jupiter, and Saturn. Neptune's atmosphere, while similar to Jupiter's and Saturn's in that it is composed primarily of hydrogen and helium, along with traces of hydrocarbons and possibly nitrogen, contains a higher proportion of "ices" such as water, ammonia, and methane. Astronomers sometimes categorise Uranus and Neptune as "ice giants" in order to emphasise these distinctions. The interior of Neptune, like that of Uranus, is primarily composed of ices and rock. Traces of methane in the outermost regions in part account for the planet's blue appearance.
In contrast to the relatively featureless atmosphere of Uranus, Neptune's atmosphere is notable for its active and visible weather patterns. For example, at the time of the 1989 Voyager 2 flyby, the planet's southern hemisphere possessed a Great Dark Spot comparable to the Great Red Spot on Jupiter. These weather patterns are driven by the strongest sustained winds of any planet in the Solar System, with recorded wind speeds as high as 2,100 kilometres per hour (1,300 mph). Because of its great distance from the Sun, Neptune's outer atmosphere is one of the coldest places in the Solar System, with temperatures at its cloud tops approaching −218 °C (55 K). Temperatures at the planet's centre are approximately 5,400 K (5,000 °C). Neptune has a faint and fragmented ring system (labeled 'arcs'), which may have been detected during the 1960s but was only indisputably confirmed in 1989 by Voyager 2.
Other articles related to "neptune":
... Neptune High is a high-school in the fictional seaside city of Neptune, California, attended by Veronica in the first two seasons ... Neptune's main rival is Pan High, who are known to perform pranks on each other every year ... Neptune High also had a policy of "Pirate Points", where students who were involved in certain activities, like sports, student council, and cheerleading, were allowed extra privileges (like getting ...
... Titan or the seven-cylinder 315 hp (235 kW) Neptune ... by Cyril Uwins on 25 October 1929, after its appearance with a mock-up Neptune engine at the Olympia Aero Show in July that year, where its well-appointed cabin impressed visitors but ... The Neptune was installed in January 1930 and testing proceeded satisfactorily until the aircraft was damaged in a landing accident in early February as there were no orders in sight, it was decide to abandon the ...
... Neptune has a huge gap between the rich "09ers" and those who work for them either directly or through service industry businesses ... In Veronica's words, if you live in Neptune, "either your parents are millionaires, or your parents work for millionaires" ... Echolls and his family) choose to live in Neptune due to its warm climate and its beaches, thus contributing even more to its economy ...
... Neptune, New Jersey can refer to Neptune Township, New Jersey Neptune City, New Jersey ...
... The Neptune Grand is a luxury hotel, mainly catering to the upper class, as opposed to the cheaper Camelot Motel ... Kane was innocent of his daughter's murder because he had been at the Neptune Grand with Lianne at the time of Lilly's death ... Logan held the "alterna-prom" in his suite when Neptune High canceled the prom ("Look Who’s Stalking") and also held a graduation party there ...
Famous quotes containing the word neptune:
“But we are spirits of another sort.
I with the mornings love have oft made sport,
And like a forester the groves may tread
Even till the eastern gate, all fiery-red,
Opening on Neptune with fair blessèd beams,
Turns unto yellow gold his salt green streams.”
—William Shakespeare (15641616)
“His nature is too noble for the world;
He would not flatter Neptune for his trident,
Or Jove fors power to thunder.”
—William Shakespeare (15641616)