Uranus is the 8th planet from the sun, about 1.78 billion miles away with a day lasting 17.24 hours. It is a gas giant composed primarily of hydrogen, helium and various ices, with possible liquid oceans beneath its clouds. Voyager 2 is the only spacecraft to have visited Uranus, providing data about its composition and climate during its 1986 flyby.

1. Uranus8th planetBoiling Water Ocean 27 1,783,939,400 miles 17.24 hoursGas giantWilliam HershelOuter Voyager 2Hydrogen, helium, methane, water, ammoniaLord of the skies Uranus. 30,684 days -357 degrees