Neptune turned out to be almost an identical twin of Uranus. It is 57 times bigger than the Earth, but spins quite rapidly – one day lasts only 16 hours 7 minutes. Its average distance from the Sun is about 4,500 million km, and one year on Neptune lasts for almost 165 Earth years. Like Uranus, it has an atmosphere of hydrogen, helium and methane. Its interior is made of ices, with a possible rocky core. Although the atmosphere is very cold (-220 degrees C), the blue planet has some very strong winds and violent storms. Voyager 2 imaged a huge spot the size of the Earth.

How many dark narrow rings does Neptune have?