uranus

Uranus is the seventh planet from the Sun and is classified as an ice giant. It has a mass about 14.5 times that of Earth and a diameter of roughly 50,000 kilometers. Its faint blue-green color comes from methane in the upper atmosphere. Below the cloud tops lies a thick mantle of icy compounds such as water, ammonia, and methane, surrounding a rocky core, all encased in a primarily hydrogen–helium envelope.

Uranus completes an orbit around the Sun in about 84 Earth years. Its axis is tilted about 98 degrees relative to its orbital plane, so the planet essentially rolls around the Sun on its side, producing extreme seasonal variations. The planet rotates with a period of about 17 hours and 14 minutes, and it spins in a prograde direction.

The atmosphere of Uranus comprises hydrogen, helium, and methane, with temperatures around −224 degrees Celsius at the cloud tops. Methane absorbs red light, giving the planet its characteristic blue-green hue. The interior is thought to consist of a small rocky core, a mantle of ices, and a surrounding hydrogen–helium envelope. There is no well-defined solid surface.

Uranus has a ring system and numerous moons. The rings are faint and dark, composed of particles ranging in size, and were revealed through observations in the late 20th century, including a spacecraft flyby. The planet has at least several dozen moons, with Miranda, Ariel, Umbriel, Titania, and Oberon among the better known; their orbits and compositions vary widely.

Exploration to Uranus has been limited to the Voyager 2 flyby in 1986, which provided most of the current knowledge. The planet continues to be a target for future missions to study its atmosphere, rings, and magnetosphere.