Uranus, discovered through a telescope by astronomer William Herschel in 1781, is the seventh planet from the sun. Nearly the same size as its neighbor, Neptune, it has two sets of rings and at least 27 moons. A handful of different elements in various molecules make up the core and atmosphere of Uranus.

The atmosphere of Uranus consists of about 83 percent hydrogen, 15 percent helium and trace amounts of ammonia, which contains the elements of nitrogen and hydrogen. Methane gas, which is made up of carbon and hydrogen, in the atmosphere gives Uranus its blue-green color. The bulk of the mass of Uranus is in the planet's core, which consists of mostly icy water, methane and ammonia.