Solar System/Uranus

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True color photo of Uranus.

Uranus (pronounced YOUR-uh-nus or yuh-RAIN-us) is the seventh of the eight planets from the Sun and is the third largest — with a diameter of 51118 kilometers, it is just 3% larger than Neptune but 4.0 times as large as Earth. Uranus is one of the four gas giants. If Uranus had a solid surface and you stood on it, you would weigh 89% as much as you do on Earth.

Orbit[edit | edit source]

Uranus orbits the Sun once every 84.01 Earth-years, at an average distance of 19.19 AU (Earth-Sun distances) and with an orbital eccentricity of .046.

Rotation[edit | edit source]

The rotational period of Uranus is 17 hours 14 minutes. The tilt of its axis based on prograde motion (motion in the direction of the orbit) is 97.86° from the perpendicular of its orbital plane. In other words, it is tilted by 82.14° and rotates retrograde. Because it is essentially tipped over on its side, almost all points on Uranus experience both a directly overhead noon Sun at times during the orbit and days when the Sun never rises at other times during the orbit. On Earth the former occurs in locations that are closer to the equator than 23.45° latitude because Earth's rotational axis is tilted 23.45° from the perpendicular of its orbital plane, and the latter occurs in locations that are closer than 23.45° degrees to the north or south pole. On Uranus the overhead Sun occurs at any location within 82.14° of the equator — that is, almost everywhere on the planet; and days without sunrise occur at any location within 82.14° of the north or south pole — again almost everywhere on the planet. Uranus is the only planet in the solar system having any locations that experience both types of event.

Titania[edit | edit source]

Titania is Uranus's largest satellite, with a diameter of 1578 kilometers.

Rings[edit | edit source]

False color image of Uranus in IR, showing rings.

Distance Width
Ring (km) (km)

-------- -----

1986U2R 38000 2,500
6 41840 1-3
5 42230 2-3
4 42580 2-3
Alpha 44720 7-12
Beta 45670 7-12
Eta 47190 0-2
Gamma 47630 1-4
Delta 48290 3-9
1986U1R 50020 1-2
Epsilon 51140 20-100

(distance is from Uranus' center to the ring's inner edge)