Uranus, pronounced YUR uh nuhs or pronounced yu RAY nuhs, is the seventh planet from the sun. Only Neptune and Pluto are farther away. Uranus is the farthest planet that can be seen without a telescope. Its mean distance from the sun is about 1,786,400,000 miles (2,875,000,000 kilometers), a distance that takes light about 2 hours 40 minutes to travel.
Uranus is a giant ball of gas and liquid. Its diameter is 31,763 miles (51,118 kilometers), over four times that of Earth. The surface of Uranus consists of blue-green clouds made up of tiny crystals of methane. The crystals have frozen out of the planet's atmosphere. Far below the visible clouds are probably thicker cloud layers made up of liquid water and crystals of ammonia ice. Deeper still--about 4,700 miles (7,500 kilometers) below the visible cloud tops--may be an ocean of liquid water containing dissolved ammonia. At the very center of the planet may be a rocky core about the size of Earth. Scientists doubt that Uranus has any form of life.
Uus was the first planet discovered since ancient times. British astronomer William Herschel discovered it in 1781. Johann E. Bode, a German astronomer, named it Uranus after a sky god in Greek mythology. Most of our information about Uranus comes from the flight of the United States spacecraft Voyager 2. In 1986, that craft flew within about 50,000 miles (80,000 kilometers) of the planet's cloud tops. 9 THIN, DARK RINGS. |
