The definition of Uranus is the seventh planet from the Sun in the Solar System.
Facts About Uranus
- Uranus was discovered by Sir William Herschel a German-born astronomer from Britain on March 13, 1781. Although Uranus had been seen in the sky before this time, it was dismissed as being a star and not a planet.
- Before the planet was called Uranus in 1850, it was first called Georgium Sidus, or the Georgian Planet in honor of King George III of England.
- Uranus is 1,784,860,000 miles from the Sun.
- Its orbit takes 30,685 Earth days, which is a bit more than 84 years.
- Uranus tilts on its side, and it leans so far over that its axis is level with its orbit. Uranus is tilted almost 98 degreesversus Earth's tilt of 23.5 degrees. It is believed that this severe tilt happened when a massive object struck Uranus when it was forming or soon after it formed.
- The length of one day is around 17 hours; but, if you are on one of the poles, a day would last 42 years.
- It is closer to the Sun than Neptune, but it is colder. The temperature in the atmosphere is around -355 degrees F.
- Uranus does not have a very hot core that emits infrared radiation like other large planets. It absorbs more heat than it gives off because something in the past caused its core to cool down. The core is probably rocky.
- The composition of the atmosphere is 83% hydrogen, 15% helium, 2% methane, and a small percentage of ethane and other gases. Methane absorbs red light waves, so Uranus appears bluish green with clouds of methane crystals in its atmosphere. Lower in the atmosphere are clouds of water and ammonia ice crystals.
- The rings that surround Uranus are very different because they are dark. They are also very narrow, only a few miles wide. They are made of ice and rock and it is surmised that they are very young.
- It has at least 27 moons. Some of these moons are known as "icy moons" because they have no atmosphere or magnetosphere and they have no possibility of life.
- Most of what we know of Uranus comes Voyager 2 that flew within 50,000 miles of the tops of the clouds in 1986. It took a multitude of pictures of it and its moons.
An example of Uranus is one of the four gas giants along with Jupiter, Saturn and Neptune.