Neptune

Neptune

Planet · 30.07 AU from the Sun

Neptune facts

Type
Planet
Distance from the Sun
30.07 AU (4.5 × 10⁹ km)
Orbital period (year)
165 Earth years
Diameter
49,244 km
Mass
1.02 × 10²⁶ kg
Moons
16
Rotation period (day)
16.1 hours
Axial tilt
28.32°
Mean temperature
-200 °C
Discovered
1846, by Le Verrier, Galle and Adams

Orbit

Compressed scale; positions shown for 2026.

About Neptune

Neptune is the eighth and most distant planet, a deep-blue ice giant with the fastest winds in the Solar System, exceeding 2,000 km/h. It was the first planet found by mathematical prediction rather than observation, from the way it tugged on Uranus's orbit.

Neptune: frequently asked questions

What is Neptune?
Neptune is a planet in our Solar System, orbiting the Sun at an average distance of 30.07 AU (4.5 × 10⁹ km). Neptune is the eighth and most distant planet, a deep-blue ice giant with the fastest winds in the Solar System, exceeding 2,000 km/h.
How far is Neptune from the Sun?
Neptune orbits the Sun at an average distance of 30.07 AU, about 4.5 × 10⁹ km. One AU is the Earth-Sun distance, so Neptune is roughly 30.1 times Earth's distance from the Sun.
How long is a year on Neptune?
Neptune takes 165 Earth years to complete one orbit of the Sun, which is one Neptune year. By Kepler's third law, bodies farther from the Sun take longer to go around.
How many moons does Neptune have?
Neptune has 16 known moons.
How big is Neptune?
Neptune has a diameter of about 49,244 km and a mass of roughly 1.02 × 10²⁶ kg.

See Neptune in motion

Open the interactive Solar System orrery →

Data from NASA/JPL and NSSDCA. Source.