Oberon (moon) Oberon (moon) Oberon, also designated , is the outermost major moon of the planet Uranus. It is the second-largest and second most massive of the Uranian moons, and the ninth most massive moon in the Solar System. Discovered by William Herschel in 1787, Oberon is named after the mythical king of the fairies who appears as a character in Shakespeare's "A Midsummer Night's Dream". Its orbit lies partially outside Uranus's magnetosphere. It is likely that Oberon formed from the accretion disk that surrounded Uranus just after the planet's formation. The moon consists of approximately equal amounts of ice and rock,
Formation and evolution of the Solar System many planetary scientists think that the Solar System might have looked very different after its initial formation: several objects at least as massive as Mercury were present in the inner Solar System, the outer Solar System was much more compact than it is now, and the Kuiper belt was much closer to the Sun. At the end of the planetary formation epoch the inner Solar System was populated by 50–100 Moon- to Mars-sized planetary embryos. Further growth was possible only because these bodies collided and merged, which took less than 100 million years. These objects would have gravitationally interacted with