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Uranus |
Uranus is an "ice giant". It has the third-largest planetary radius and fourth-largest planetary mass in the Solar System. |
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Orbital period |
84 Earth years |
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Etymology |
It is the only planet whose name is derived from a figure from Greek mythology rather than Roman mythology like the other planets, from the Latinized version of the Greek god of the sky, Ouranos. |
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Atmosphere |
It is the coldest planetary atmosphere in the Solar System, with a minimum temperature of 49 K (−224.2 °C), and has a complex, layered cloud structure, with water thought to make up the lowest clouds, and methane the uppermost layer of clouds.The interior of Uranus is mainly composed of ices and rock. |
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Tilt |
Uranus has an axial tilt of 97.77°, so its axis of rotation is approximately parallel with the plane of the Solar System. This gives it seasonal changes completely unlike those of the other major planets. Other planets can be visualized to rotate like tilted spinning tops on the plane of the Solar System, but Uranus rotates more like a tilted rolling ball. Near the time of Uranian solstices, one pole faces the Sun continuously and the other one faces away. Only a narrow strip around the equator experiences a rapid day–night cycle, but with the Sun low over the horizon as in the Earth's polar regions. At the other side of Uranus's orbit the orientation of the poles towards the Sun is reversed. Each pole gets around 42 years of continuous sunlight, followed by 42 years of darkness. |
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Wind |
The wind speeds on Uranus can reach 250 metres per second (900 km/h, 560 mph) |
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Moons |
Uranus has 27 known natural satellites. The names for these satellites are chosen from characters in the works of Shakespeare and Alexander Pope. The five main satellites are
The Uranian satellite system is the least massive among those of the giant planets; the combined mass of the five major satellites would be less than half that of Triton (largest moon of Neptune) alone. |