The following outline is provided as an overview of and topical guide to Neptune:

Neptune – eighth and farthest known planet from the Sun in the Solar System. In the Solar System, it is the fourth-largest planet by diameter, the third-most-massive planet, and the densest giant planet. Neptune is 17 times the mass of Earth and is slightly more massive than its near-twin Uranus, which is 15 times the mass of Earth and slightly larger than Neptune.Neptune is denser and physically smaller than Uranus because Neptune's greater mass gravitationally compresses the atmosphere more. Neptune orbits the Sun once every 164.8 years at an average distance of . It is named after the Roman god of the sea and has the astronomical symbol ♆, a stylised version of the god Neptune's trident.

Classification of Neptune

Astronomical object Gravitationally rounded object Planet Giant planet Ice giant Planet of the Solar System Outer planet Superior planet

Location of Neptune

Milky Way Galaxy – barred spiral galaxy Orion Arm – a spiral arm of the Milky Way Solar System – the Sun and the objects that orbit it, including 8 planets, the eighth and furthest planet from the Sun being Neptune Orbit of Neptune

Movement of Neptune

Orbit of Neptune Rotation of Neptune

Features of Neptune

Atmosphere of Neptune Rings of Neptune

Natural satellites of Neptune

Moons of Neptune

Inner moons of Neptune

Naiad Thalassa Despina Galatea Larissa Hippocamp Proteus Retrograde moons of Neptune

Triton Atmosphere of Triton Climate of Triton Geology of Triton List of geological features on Triton Halimede Psamathe Neso S/2021 N 1 Prograde moons of Neptune

Nereid Sao Laomedeia S/2002 N 5

History of Neptune

History of Neptune Discovery of Neptune

Exploration of Neptune

Exploration of Neptune

Flyby missions to explore Neptune

Voyager 2

Future of Neptune exploration

Proposed missions to explore Neptune

Interstellar Express Neptune Orbiter ODINUS Trident

See also Outline of astronomy Outline of the Solar System Outline of space exploration

Notes

References

External links

NASA's Neptune fact sheet Neptune from Bill Arnett's nineplanets.org Neptune Astronomy Cast episode No. 63, includes full transcript. Neptune Profile at NASA's Solar System Exploration site Planets – Neptune A children's guide to Neptune.

Neptune by amateur (The Planetary Society)