Neptune / eighth and farthest known planet from the Sun / Space World

Neptune is the eighth and farthest known planet from the Sun in the Solar System. In the Solar System, it is the fourth-largest planet by diameter, the third-most-massive planet, and the densest giant planet.

Mass: 1.024 × 10^26 kg (17.15 M⊕)
Distance from Sun: 4.495 billion km
Orbital period: 165 years
Radius: 24,622 km
Moons: Triton, Nereid, Proteus, Thalassa, Despina, Galatea, Neso,
Did you know: A planet must orbit the sun, which Neptune does – once every 165 years. 

Neptune The eighth planet from the sun, Neptune is known for strong winds — sometimes faster than the speed of sound. Neptune is far out and cold. The planet is more than 30 times as far from the sun as Earth. It has a rocky core. Neptune was the first planet to be predicted to exist by using math, before it was detected. Irregularities in the orbit of Uranus led French astronomer Alexis Bouvard to suggest some other might be exerting a gravitational tug. German astronomer Johann Galle used calculations to help find Neptune in a telescope. Neptune is about 17 times as massive as Earth.

Discovery: 1846
Named for: Roman god of water
Diameter: 30,775 miles (49,530 km)
Orbit: 165 Earth years
Day: 19 Earth hours
Related:
More Neptune Facts
Neptune Pictures
NASA Solar System Exploration: Neptune