Neptune

Neptune is the eighth and farthest-known Solar planet from the Sun. In the Solar System, it is the fourth-largest planet by diameter, the third-most-massive planet, and the densest giant planet. It is 17 times the mass of Earth, slightly more massive than its near-twin Uranus. Neptune is denser and physically smaller than Uranus because its greater mass causes more gravitational compression of its atmosphere. The planet orbits the Sun once every 164.8 years at an average distance of 30.1 AU. It is named after the Roman god of the sea and has the astronomical symbol, representing Neptune's trident. A second symbol, an L-V monogram for 'Le Verrier', analogous to the H monogram for Uranus, was never much used outside of France and is now archaic. Neptune is not visible to the unaided eye and is the only planet in the Solar System found by mathematical prediction rather than by empirical observation.

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From Diamond Rain to Hidden Oceans: The True Secrets of Uranus and Neptune

A clue to what lies beneath the bland surfaces of Uranus and Neptune

Uranus and Neptune May Conceal Vast Oceans of Water

A Mission to Triton and Neptune Would Unlock Their Mysteries

An Ambitious Mission to Neptune Could Study Both the Planet and Triton

Space photo of the week: 1st-ever close-up of Neptune is Voyager 2's final portrait of a planet

Scientists identify a ‘sugar world’ beyond Neptune

Pluto and the largest moon of Neptune might be siblings

Why is Neptune's magnetic field so weird? An exotic molecule may be the answer

An outlandish molecule may be lurking inside Uranus and Neptune, affecting their magnetic fields

A Mini-Neptune in the Habitable Zone in a Binary Star System

Discovery Alert: Mini-Neptune in Double Star System is a Planetary Puzzle

When Uranus and Neptune Migrated, Three Icy Objects Were Crashing Into Them Every Hour!

Evidence for Planet 9 found in icy bodies sneaking past Neptune

Uranus and Neptune aren't made of what we thought, new study hints

Cosmic Puzzles: New Research Sheds Light on Why Our Solar System Lacks a Mini-Neptune

Webb Reveals Secrets of Neptune’s Evolution

Webb Space Telescope Unlocks the Icy Secrets of Neptune’s Birth

Icy asteroids help the James Webb Space Telescope uncover Neptune's history