Astronomers use a term called astronomical units to measure vast lengths in space. An AU is equivalent to the average distance between the Earth and the sun. This means that Uranus has an average distance of 19.2 AU from the sun.
Uranus was discovered by John Flamsteed in 1690, making it the first planet discovered in the modern era. At the time, Flamsteed thought Uranus was a star in the constellation Taurus. This idea was accepted until 1781, when Sir William Herschel discovered that Uranus was actually a planet.Learn more about Planets