The Solar System

Neptune

The farthest planet: a deep blue ice giant with the fastest winds in the Solar System, up to 2,000 km/h.

Neptune
Neptune from Voyager 2 in August 1989, with the Great Dark Spot, a storm as wide as Earth. Credit: NASA/JPL, Public domain (NASA).
Size
49,528 km across. About 3.9 times as wide as Earth.
One year
165 Earth years
One day
16 h 6 min
Moons
16 known, the largest is Triton
Spacecraft
Only Voyager 2 has visited, flying past in August 1989.

Sizes and periods from NASA’s planetary fact sheets; moon counts from NASA Science.