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Ice giant

Uranus

The tilted planet

Uranus is the seventh planet from the Sun and the first discovered with a telescope, found by William Herschel in 1781. It is an ice giant, with a bulk made of water, methane, and ammonia ices around a rocky core. Uranus is tipped over almost completely on its side, likely from a giant ancient collision, so it rolls around the Sun like a ball. Methane in its atmosphere absorbs red light, giving Uranus its calm blue-green color.

Quick facts

Distance from Sun
2.9 billion km (19.2 AU)
Diameter
50,724 km (4x Earth)
Day length
17.2 hours (retrograde)
Year length
84 Earth years
Moons
28 confirmed
Avg. temperature
-195 C

What's it like there?

Because Uranus spins on its side, its seasons are extreme: each pole gets about 21 years of continuous sunlight followed by 21 years of darkness. It is the coldest planetary atmosphere in the solar system, dipping to -224 C, even though Neptune is farther from the Sun. Beneath the hazy blue-green clouds, scientists believe a hot, dense fluid of icy materials surrounds a small rocky core. It also has 13 faint rings.

Notable moons

  • Titania

    Largest moon of Uranus, with huge canyons.

  • Miranda

    A patchwork world with cliffs up to 20 km tall.

Fun facts

  • Uranus rotates on its side with an axial tilt of about 98 degrees.

  • It is the coldest planet, reaching -224 C, despite not being the farthest.

  • Its 28 moons are named after characters from Shakespeare and Alexander Pope.

  • A single Uranus year lasts 84 Earth years.

  • Uranus was the first planet discovered with a telescope (1781).

Exploration history

  1. Voyager 2 1986

    The only spacecraft to have visited Uranus, discovering 10 new moons.

Uranus vs Earth

PropertyEarthUranus
Diameter12,742 km50,724 km
Year length365 days84 years
Moons128
Average temperature15 C-195 C
Axial tilt23.5 deg97.8 deg

Scientific Sources & Provenance

All data is verified against official space agency records (NASA, ESA, and IAU).