Uranus

    Uranus is the seventh planet from the moon and is the third largest. It was discovered in 1781 by William Herschel. It has a diameter of 51,800 kilometers. It s mass is 14 times of Earth's and 4 times of Earth's in radius. It orbits the Sun once every 84.01 Earth years. It has a distance from the Sun of 2.87 billion kilometers. Uranus is also the third giant gas planet. A day on Uranus is 17 hours 14 minutes. The atmosphere of Uranus is made of 83% hydrogen, 15% helium, 2% methane and little amounts of acetylene and other hydrocarbons. Methane absorbs red light, giving Uranus its blue-green color. It has a atmosphere pressure of 1.2(bar). Like Neptune Uranus contains more amounts of heavy elements than Jupiter or Saturn. Uranus is covered with clouds. In the upper atmosphere of Uranus its only 58 degrees K (Kelvin).

Uranus is tipped on its side. Its position is thought to be the result of a crash with a planet-sized body in the early times. The rotation axis is 8 degrees out of the plane of its orbit. The tail of the magnetic field is itself tilted 60 degrees from the planet's axis of rotation. The magnetic field itself is about 50 times stronger than that of the Earth.  

Before telescopes were invented people who saw Uranus thought that it was a star. After telescopes were invented observers observed it more closely and realized that it was a planet all along. Documents that were dated back to 1690 cataloged it as a star. 

Uranus' Rings

Uranus' first nine rings were discovered in 1977. Then two more were discovered. That brings a total of 11 rings. No material can be detected between the rings. The rings' brightness vary their angle to the Sun. The brightest ring is the Epsilon ring. Uranus' rings are different from Jupiter and Saturn's rings. There possibly may be incomplete rings or ring arcs. They are as small as 50 meters (160 feet) in width. Uranus' rings are less extensive than of Saturn's. Also it may be rock rather than ice. 

Uranus' Moons

Uranus has at least 22 moons. The two largest moons are Titania and Oberon. There are 5 large moons and 10 small ones. Five of Uranus' many moons are Miranda, Ariel, Umbriel, Titania, and Oberon. Miranda is 500 km in diameters.