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Uranus – Planet · Ice giant
Image: Ardenau4 · CC0
🪐 Planets · The Giants

Uranus

Planet · Ice giant

Uranus is an ice giant that rolls around the Sun on its side, probably knocked over by an enormous collision long ago. Methane gas in its atmosphere gives it a pale blue-green colour.

  • 50,724 kmAbout 4 Earths would fit side by side across it.
  • 84 yearsYear
  • 98°Tilt
🔭 Find it in the sky

Take a closer look

What’s an ice giant?

Uranus has no solid surface. Under its hydrogen and helium air lies a hot, dense, slushy layer of water, ammonia and methane – the “ices” that give ice giants their name – wrapped around a small rocky core. Its cloud tops are among the coldest places in the Solar System, dipping to about −224 °C.

A moon with giant cliffs

Uranus’ moon Miranda looks like a patchwork quilt, with grooved, jumbled regions that seem stitched together. It has one of the tallest cliffs known in the Solar System, many kilometres high. With Miranda’s weak gravity, a rock dropped off the edge would take minutes to reach the bottom.

Waiting for a visitor

Only one spacecraft has ever visited Uranus, so scientists study it with telescopes. In 2023 the James Webb Space Telescope photographed its faint rings glowing in infrared light. US planetary scientists have chosen a Uranus orbiter and probe as their top choice for the next big flagship mission.

Size it up

EarthUranus

About 4 Earths would fit side by side across it. Both are drawn to the same scale.

How we found out

  1. 1781

    William Herschel discovers Uranus with his homemade telescope – the first planet found with a telescope. He wanted to name it after King George III.

  2. 1787

    Herschel finds its two largest moons, Titania and Oberon.

  3. 1977

    Rings are discovered when Uranus passes in front of a star and the starlight flickers.

  4. 1986

    Voyager 2 flies past – still the only spacecraft ever to visit.

🤔 Something to wonder about

Why are Uranus’ moons named after characters from Shakespeare?

See it yourself

Just barely visible to the eye from a very dark site. Binoculars show a tiny blue-green dot.

Got it?

Mark Uranus as explored to earn 10 XP.