The seventh planet of the solar system was named after Uranus, god of the heavens and father of Saturn. It was discovered in 1781 by the astronomer William Herschel.
Initially, he was convinced that he had observed a new comet. Uranus' axis is heavily inclined to the plane of its orbit. We could actually say that Uranus is "lying" on its plane of orbit. During its revolution about the Sun, which takes approximately 84 years, each of the planet's poles is exposed to the Sun for 42 years. A Uranus day is only 17.3 hours.
The planet rotates in retrograde direction about its axis. Uranus also has a ring system, but it is less prominent than that of Saturn. The individual rings measure between one and one hundred kilometers in thickness. Uranus' mass is about 15 times that of the Earth. Uranus belongs to the "gas giant" planets. Its interior consists of a rocky core.
This solid body is surrounded by a layer of ammonium, water and methane. The upper atmosphere of the planet consists mainly of hydrogen and helium, with a substantial trace of methane. It is actually this gas, which gives the planet its greenish appearance.
