Date of the discovery: 13 March 1781

Short Description: Uranus was discovered by William Herschel. Today William Herschel is known as an respected astronomer. At the time of the discovery he was an amateur astronomer. At first he classified the discovery as a comet and only later he recognized it was a major planet. Uranus is the first discovered Ice Giants in the solar system, meaning its composition is different from the Gas Giants Jupiter and Saturn. The Ice Giants formed from material, which is referred to as “ice”, but not only water ice, but also ammonia ice or methane ice. The Ice Giants have a less thick atmosphere than the Gas Giants, but the atmosphere is still thick enough to make direct observations of the surface impossible. Urarnus has 27 known moons and a ring system. The rotational axis is the most inclined, with 97.77°, causing extreme seasonal changes of the planet in the 84 (earth-)year orbit.

Amateur Astronomer(s): William Herschel

Telescope probably involved: seven foot long, six inch diameter, ƒ14 reflector

Credit for the header image: Voyager 2 NASA/JPL-Caltech

Go back to the timeline↵