Ice Giant · Updated May 2026
Uranus.
Uranus is the seventh planet from the Sun, an ice giant tilted nearly 98° so it rolls along its orbit on its side. With a diameter of 50,724 km and an 84-Earth-year orbit, it is the third-largest planet by radius and the coldest planetary atmosphere in the solar system, with cloud-top temperatures around −224 °C. Its pale blue-green colour comes from methane in the upper atmosphere absorbing red light.
Open Uranus in the viewer →Key facts
Uranus's 97.77° axial tilt means each pole spends 42 Earth years in continuous sunlight, then 42 in continuous darkness. In the viewer this is most obvious if you watch from the side — the orbit looks normal, but the rotation axis stays pointed at a fixed star while the planet circles the Sun.
Atmosphere
83% hydrogen, 15% helium, 2% methane. The methane is what gives Uranus its colour — it absorbs red wavelengths and reflects blue. Below the visible cloud deck of methane ice are cloud layers of hydrogen sulphide, ammonia hydrosulphide, and water.
Surface
No solid surface. Moving inward, the atmosphere thickens into a hot, dense fluid of water, methane, and ammonia — sometimes called an "ice mantle" though it's actually a supercritical fluid at thousands of degrees and millions of atmospheres of pressure.
Interior
A small rocky core, a thick mantle of "icy" supercritical fluid (water, methane, ammonia), and a hydrogen / helium envelope. Unlike Jupiter or Saturn, Uranus radiates almost no excess heat — a long-standing puzzle.
Formation
Likely formed closer to the Sun and migrated outward during the early solar system's gravitational reshuffling. The extreme tilt is best explained by one or more giant impacts during formation.
Orbit
Average distance from the Sun: 2.87 billion km (19.2 AU). Orbital period 84 Earth years. Has 13 known faint rings, narrower and darker than Saturn's, made mostly of dark particles.
Major moons
- Miranda — Miranda has one of the most extreme and varied landscapes in the Solar System, with giant canyons.
- Ariel — Ariel is the brightest of Uranus's moons with a relatively young surface.
- Umbriel — Umbriel is the darkest of Uranus's large moons with ancient, heavily cratered terrain.
- Titania — Titania is the largest moon of Uranus, with huge fault systems and canyons.
- Oberon — Oberon is the second largest moon of Uranus, heavily cratered with mysterious dark patches.
Notable missions
- Voyager 2 (1986 · Past flyby) — The only spacecraft ever to visit Uranus. Every modern image of the planet still relies on that single 1986 flyby.
- Uranus Orbiter and Probe (Proposed 2030s · Concept) — Top priority flagship in the 2023 Planetary Science Decadal Survey.
How to view Uranus in 3D
This page is part of an interactive 3D solar system viewer built with Three.js, WebGL 2.0, and custom GLSL shaders. Uranus orbits the Sun in real time alongside every other planet, with adjustable time speed, scale sliders, and a fly mode that lets you pilot a spacecraft between bodies under realistic gravity.
Fly to Uranus now →Frequently asked questions
Why does Uranus rotate on its side?
Most likely a series of giant impacts during the early solar system tipped it over.
How many moons does Uranus have?
28 confirmed, named after Shakespearean and Pope characters — Miranda, Ariel, Umbriel, Titania, Oberon, and 23 more.
How was Uranus discovered?
William Herschel found it in 1781 — the first planet discovered with a telescope rather than the unaided eye.
Sources & methodology
Numbers cross-referenced with the sources below; surface and atmosphere descriptions reflect findings as of May 2026. Renderings in the 3D viewer use textures based on Solar System Scope and NASA imagery.