General Information

Average distance from the Sun

2,871 million km
(1800 million miles)

Time to orbit Sun

84 Earth years

Average rotation period

17 hours 54 minutes

Diameter at equator

51,118 km
(31,763 miles)

Approximate surface temperature

- 180 0C

Uranus is the seventh planet from the Sun. It was first identified as a planet by the British astronomer William Herschel in 1781.

Uranus spins on its side. No other planet does this. Many astronomers think that its unusual spin is the result of a collision with a planet-sized object million of years ago. Like Saturn and Jupiter, Uranus has rings. They were first discovered from Earth in 1977. Mostly, the rings are made up of dust.

The atmosphere of Uranus is mostly hydrogen gas, with helium and tiny amounts of other gases. The upper atmosphere contains a lot of helium, which makes Uranus look blue-green. The planet has a small, rocky core.

Uranus spins quickly, taking just 18 hours to make one complete turn. Earth takes 24 hours to spin once, but Uranus is far larger, so at its cloud tops is moves far faster than the Earth.

In its orbit of the Sun, Uranus moves through space at about 7 Km per second. Uranus has at least 15 moons, although there may be more that are yet to be discovered. Its five biggest moons are shown above. Ariel and Umbriel are both dark and cratered, while Titania has deep, long valleys. Oberon is heavily cratered, but little else is known about its moon. Miranda is a small ball of battered ice, only 472 km across. It is thought that it may once have been broken apart by a comet.