Umbriel is an Uranus satellite discovered in 1851 by William Lassell at the same time as Ariel, and named after a character in English literature. The name was suggested in 1852 by John Herschel, son of the discoverer of Uranus, William Herschel, at the request of Lassell himself. It is mainly made up of ice with a substantial part of rock and its interior can be differentiated into a rocky core and an ice sheet. The surface is the darkest of Uranus' main satellites (thus its name is reminiscent of the Latin word «umbra», shadow in English) and appears to have been sculpted primarily by impacts. However, the presence of canyons suggests that it has undergone early endogenous processes that caused surface rejuvenation and erased the oldest terrain.
