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Neptune: Difference between revisions
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==Status== | ==Status== | ||
From its discovery in 1846 until the discovery of Pluto in 1930, Neptune was the farthest known planet. When Pluto was discovered, it was considered a planet, and Neptune thus became the second-farthest known planet, except for a 20-year period between 1979 and 1999 when Pluto's elliptical orbit brought it closer than Neptune to the Sun, making [[Neptune]] the ninth planet from the Sun during this period. The increasingly accurate estimations of Pluto's mass from ten times that of Earth's to far less than that of the Moon and the discovery of the [[Kuiper Belt]] in 1992 led many astronomers to debate whether [[Pluto]] should be considered a planet or as part of the Kuiper belt. In 2006, the International Astronomical Union defined the word "planet" for the first time, reclassifying Pluto as a "dwarf planet" and making [[Neptune]] once again the outermost-known planet in the Solar System. | From its discovery in 1846 until the discovery of Pluto in 1930, Neptune was the farthest known planet. When Pluto was discovered, it was considered a planet, and Neptune thus became the second-farthest known planet, except for a 20-year period between 1979 and 1999 when Pluto's elliptical orbit brought it closer than Neptune to the Sun, making [[Neptune]] the ninth planet from the Sun during this period. The increasingly accurate estimations of Pluto's mass from ten times that of Earth's to far less than that of the Moon and the discovery of the [[Kuiper Belt]] in 1992 led many astronomers to debate whether [[Pluto]] should be considered a planet or as part of the Kuiper belt. In 2006, the International Astronomical Union defined the word "planet" for the first time, reclassifying Pluto as a "dwarf planet" and making [[Neptune]] once again the outermost-known planet in the Solar System. | ||
==Moons== | |||
For a timeline of discovery dates, see Timeline of discovery of Solar System planets and their moons. | |||
Shown in this image are Neptune and its moons: Triton, Galatea, Naiad, Thalassa, Despina, Proteus, and Larissa | |||
An annotated picture of Neptune's many moons as captured by the James Webb Space Telescope. The bright blue diffraction star is Triton, Neptune's largest moon. Neptune has 16 known moons. Triton is the largest Neptunian moon, accounting for more than 99.5% of the mass in orbit around Neptune, and is the only one massive enough to be spheroidal. | |||
==Naming== | ==Naming== | ||