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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

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

Neptune at Opposition II Cranking up the winds on a distant planet August 30, 2015

Neptune at Opposition Neptune in the sky with diamonds August 29, 2015

Neptune at Opposition Lining up a blue-green giant August 26, 2014

Voyager 2 at Neptune A first glance at a giant world August 24, 2014

Neptune at Opposition Probing deep into a planet’s atmosphere August 25, 2013

Missed Opportunity Missing a “stellar” opportunity January 27, 2013

Johann Galle Taking note of a new planet June 8, 2012

Featured Images

Voyager 2 view of Neptune

Blue Planet 2 September 1, 2016

Windy Planet August 31, 2015

Diagram shows Neptune and some of its moons, including one discovered in 2013

Second-Look Moon July 22, 2013

Voyager 2 view of the Adams Ring at Neptune

Pulverized Moon August 22, 2011