Uranus is the first discovered planet. In the late 18th century, William Herschel used his little homemade telescope to identify the first new member of our solar system since ancient times.
Uranus, along with Neptune, is distinctly different from the larger gas planets, Jupiter and Saturn. The two sub-jovian planets have a very subtle blue-green color to them, due to the presence of methane in their atmospheres. Both of the outer planets have higher densities and a greater proportion of H20 in their composition. Their interiors are thought to be layered with molecular hydrogen, water, and molten rock.
Here are some of the essential facts about Uranus:
Radius 25,559 km which is about four times the size of Earth
Rotation 17 hours 17 minutes at the equator
Revolution 84 years to orbit the Sun
Semi major axis 19.2 A.U.
Atmosphere Mostly Hydrogen and some Helium. Methane in the atmosphere gives a blue-green color. A layer of carbon in the interior of Uranus may be crystalized to form diamonds!
Cloud Features Nearly featureless, at least to the unaided eye.
Moons or rings Uranus has a number of small icy moons. Several small moons have been discovered recently. These new moons act as shepherd satellites to keep the rings in line. Unlike Saturn, the ring particles of Uranus rings consist of dirty ice.
Space Probes Uranus has been visited only by Voyager II, in 1986.
