Uranus was found in 1781 by the astronomer Sir William Herschel.
Uranus was the first planet to be discovered with the help of a telescope. (All the others are bright enough to be seen without one.)
Nearly 200 years after its discovery, in 1977, astronomers discovered that Uranus has a system of rings around it. They are too faint to be seen directly from Earth, even with a powerful telescope but, in 1977, Uranus' path through the sky took it directly in front of a star. The starlight was observed to dim and brighten again several times before the star disappeared behind the planet. The same thing happened just after the star reappeared. A set of rings around Uranus was the only sensible explanation. The existence of eleven seperate rings was confirmed when Voyager 2 passed only 46,600 miles (75,000 km) away from Uranus in 1986. They are made of pieces of rock as dark as coal.
Uranus probably has a small rocky core but the bulk of the planet is a mantle made of rock, water, methane, and ammonia. Deep inside the planet, the mixture will be a hot liquid, but near the surface it is frozen. The outermost layer is an atmosphere, mainly of Hydrogen, with helium and small amounts of other chemicals, including Methane.
The axis Uranus spins around is tilted right over to lie nearly the main plane of the Solar System. This makes Uranus unique among the planets: all the others spin with their axes at right angles to their orbits, or not too far off. Uranus appears to roll around on its side as it orbits the Sun, with its spin axis pointing towards the Sun. This means that one half of Uranus faces the Sun for many Earth years. Days and nights are 42 Earth years long on some parts of the planet.