Neptune is the farthest planet from the Sun in our solar system, taking over 165 Earth years to complete its orbit. It is a cold, windy gas giant composed of water, ammonia and methane, with weather including 16-hour days. Though smaller than other gas giants like Jupiter, Saturn and Uranus, Neptune remains one of the coldest places in the solar system, with its moon Triton holding the record as one of the coldest objects.