One year on Neptune is equal to around 165 Earth years or 60,190 Earth days, which is the amount of time it takes the planet to complete its orbit around the sun. Days on Neptune last about 16 hours, which is 8 hours less than Earth. This is the amount of time that it takes for Neptune to make a complete rotation on its axis.
Neptune is a dark planet that receives little light because it is about 2.8 billion miles from the sun. The planet is constantly subjected to cold, supersonic winds and has an atmosphere that consists primarily of methane, hydrogen and helium. Neptune has a total of six rings, 13 known moons and has only been visited by one spacecraft, the Voyager 2, as of 2015.