Umbriel orbits Uranus at the distance of about 266,000 km (165,000 mi), being the third farthest from the planet among its five major moons. Umbriel is the "dusky melancholy sprite" in Alexander Pope's The Rape of the Lock, and the name suggests the Latin umbra, meaning shadow. The names of all four satellites of Uranus then known were suggested by John Herschel in 1852 at the request of Lassell, though it is uncertain if Herschel devised the names, or if Lassell did so and then sought Herschel's permission. Īll of Uranus's moons are named after characters created by William Shakespeare or Alexander Pope. Although William Herschel, the discoverer of Titania and Oberon, claimed at the end of the 18th century that he had observed four additional moons of Uranus, his observations were not confirmed and those four objects are now thought to be spurious. Umbriel, along with another Uranian satellite, Ariel, was discovered by William Lassell on October 24, 1851. It took several images of Umbriel, which allowed mapping of about 40% of the moon's surface. The Uranian system has been studied up close only once, by the spacecraft Voyager 2 in January 1986. This moon, like all moons of Uranus, probably formed from an accretion disk that surrounded the planet just after its formation. The most prominent surface feature is a ring of bright material on the floor of Wunda crater. However, the presence of canyons suggests early endogenic processes, and the moon may have undergone an early endogenically driven resurfacing event that obliterated its older surface.Ĭovered by numerous impact craters reaching 210 km (130 mi) in diameter, Umbriel is the second most heavily cratered satellite of Uranus after Oberon. The surface is the darkest among Uranian moons, and appears to have been shaped primarily by impacts. Umbriel consists mainly of ice with a substantial fraction of rock, and may be differentiated into a rocky core and an icy mantle. It was discovered at the same time as Ariel and named after a character in Alexander Pope's 1712 poem The Rape of the Lock. Umbriel / ˈ ʌ m b r i ə l/ is a moon of Uranus discovered on October 24, 1851, by William Lassell.
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