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The eighth planet from the Sun in the solar system. Neptune orbits the Sun at an average distance of 30 AU. The planet has a mass 17.1 times the mass of Earth and a radius 3.9 times the radius of Earth. Neptune is a gas planet made of hydrogen, helium, and methane and has no solid surface. It has a small ring system and 14 known moons, the largest of which is Triton.


Neptune's Triton February 19, 2016


Neptune February 10, 2016

Realm of the Giants June 10, 2010

Radio Programs

Neptune Opposition II Stormy skies on a blue planet September 14, 2021

Neptune at Opposition Calculating a major discovery September 13, 2021

Beyond Neptune Denizens of the deep solar system May 26, 2021

More Neptune at Opposition “Hot ice” inside a giant planet September 11, 2020

Neptune at Opposition Giving a giant planet a shove September 10, 2020

Hunting by Gravity Using gravity to track down planets July 24, 2020

Neptune Opposition II A tiny new moon for Neptune September 7, 2019

Neptune at Opposition Dark spots for a giant planet September 6, 2019

First to Neptune A giant planet’s only visitor August 25, 2019

Mars and Neptune  Orange and blue in the evening sky December 5, 2018

Neptune III The blue-planet blues September 7, 2018

More Neptune One year of observations September 6, 2018

Neptune at Opposition Lining up a hard-to-find giant September 5, 2018

More Neptune Taking a spin on a giant planet September 4, 2017

Neptune at Opposition Turning a giant planet blue September 3, 2017

Alexis Bouvard Inklings of an eighth planet June 26, 2017

More Neptune at Opposition Spotting a blemish on a giant planet September 2, 2016

Neptune at Opposition A blue marble far from the Sun September 1, 2016

Featured Images

Neptune from Voyager 2

Giant Crescent September 13, 2021

Ground-based view of clouds on Neptune

Cloudy Giant September 11, 2020

Hubble Space Telescope views of Uranus, Neptune

Big Storms February 10, 2019

Blue Neptune September 5, 2018

Voyager 2 view of the southern hemisphere of Neptune

Blue Giant September 3, 2017

Voyager 2 view of Neptune

Blue Planet 2 September 1, 2016