Solar system · Uranus

Where is Uranus right now?

Uranus, a pale blue-green planet, drawn in Exo-View

Uranus is the planet that lies on its side. It takes 84 years to go once round the Sun, at about 19 times the Earth's distance, and it spins tipped over by almost 98°. It was the first planet found with a telescope, in 1781. Exo-View puts it where it is at this moment.

Fly to Uranus See every planet

Orbit: 84 years
Distance from the Sun: 19.2 AU on average, about 2.87 billion km
Width: 50,724 km, four times the Earth's
Day: About 17 hours
Tilt: 97.8°: it rolls round the Sun on its side
Temperature: About −224 °C at the cloud tops, the coldest planetary air known
Moons and rings: More than twenty-five moons, thirteen faint rings

Found by chance

On 13 March 1781 the musician and astronomer William Herschel noticed a faint object in Gemini that was not a star: it showed a tiny disc and moved from night to night. At first he took it for a comet. It was a planet, and the first not known since ancient times. Uranus is just visible to the naked eye under a very dark sky, as a point at the limit of sight, and it had been recorded as a star many times before.

Why it is on its side

Something knocked Uranus over, probably a giant impact early in its history. Because of the tilt, each pole spends 21 years in sunlight followed by 21 years in darkness, so that its seasons are very long, and its rings and moons circle at right angles to the way they do round other planets. It is an ice giant: mostly water, ammonia and methane around a rocky core, and the methane in its air absorbs red light, giving it its pale blue-green colour.

One visit

Only one spacecraft has ever been to Uranus, Voyager 2, which passed it on 24 January 1986 and found new moons, rings and a magnetic field tipped away from the planet's axis. Uranus's moons are named for characters of Shakespeare and Pope, among them Titania, Oberon and Miranda. A mission to orbit it has been called the highest priority for the next decade of planetary science.

In Exo-View

The button below flies from the Sun out to Uranus. The clock runs faster than life, so you can watch it creep along its 84-year orbit.