Uranus is the sixth largest of the nine planets in the Solar System and the seventh out from the Sun.  Its orbit lies between the orbits of Saturn and Neptune, at a distance of about 2.9 billion km from the Sun.  The planet was accidentally discovered in 1781 by British astronomer William Herschel and was originally named Georgium Sidus (Star of George) after King George III.

It was later called Herschel, after its discoverer and was eventually named Uranus in the 19th century.  It takes a period of 84 years to revolve once around the Sun and takes 17.2 hours to rotate once about its own axis.  It is just visible to the naked eye from Earth.  Through a telescope the planet appears as a bluish-green disc with a faint green edge.
The average surface temperature on Uranus is about  -216 degrees centigrade. Its atmosphere is made up of hydrogen, helium, methane and other trace elements.  Uranus has 15 satellites, 5 discovered by telescope and 10 of them by the Voyager 2 mission.  All of them revolve around the planet's equator.  The two largest moons, Oberon and Titania, were discovered by Herschel in 1787.  The next two, Umbriel and Ariel, were found by the British astronomer William Lassell in 1851.  Miranda, the innermost of the satellites was discovered by the American astronomer, Gerard Kuiper in 1948.  Like some of the other planets, in particular Saturn, Uranus has a system of nine rings around the planet though in this case the rings are narrow and faint.

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