Neptune

Neptune is the eighth, and most distant planet from the Sun. It’s the fourth-largest, and the first planet discovered with math.

About Neptune

Dark, cold and whipped by supersonic winds, giant Neptune is the eighth and most distant major planet orbiting our Sun.

More than 30 times as far from the Sun as Earth, Neptune is not visible to the naked eye. The planet’s blue color comes from methane in its atmosphere, which absorbs red wavelengths of light, but allows blue ones to be reflected back into space – very much like its neighbor, Uranus. Neptune was the first planet located using math. German astronomer Johann Galle was the first to observe the planet in 1846. The planet is named after the Roman god of the sea.

Get the Facts

Neptune is blue and banded with clouds and storms.

This picture of Neptune was produced from images taken by NASA’s Voyager 2 in the summer of 1989 as it became the first spacecraft to fly by the planet.

NASA/JPL-Caltech

Neptune by the Numbers

How big is Neptune? How far is it from the Sun?

Use this tool to compare Neptune to Earth, and other planets.

Blue Neptune and its storms as seen from a spacecraft.

This photograph of Neptune was reconstructed from two images taken by Voyager 2.

NASA/JPL-Caltech

Neptune Exploration

Galileo recorded Neptune as a fixed star during observations with his small telescope in 1612 and 1613.

More than 200 years later, the ice giant became the first planet located through mathematical predictions rather than through observations of the sky. In 1989, NASA's Voyager 2 became the first-and only-spacecraft to study Neptune up close.

A large rocket carrying NASA's Voyager 2 spacecraft is seen through the trees as it lifts off with fire and smoke below it.

NASA's Voyager 2 lifts off on Aug. 20, 1977, from Kennedy Space Center in Florida.

NASA/JPL-Caltech

Neptune Moons

Neptune has 16 known moons.

English merchant and astronomer William Lassell discovered the first and largest of Neptune's moon – Triton – on Oct. 10, 1846, just 17 days after a Berlin observatory discovered Neptune. We don't know if Lassell had a celebratory beverage after he discovered Triton, but beer helped make the finding possible. Lassell was one of 19th century England's grand amateur astronomers. He used the fortune he made in the brewery business to finance his telescopes.

Explore Neptune's Moons