When was Umbriel discovered and who discovered it?
Umbriel was discovered on the 24th of October 1851 by British astronomer William Lassell. He spotted it at the same time as the neighboring moon Ariel, making both discoveries simultaneously.
Questions about Umbriel
Short answers, pulled from the story.
Where does Umbriel get its name?
Umbriel is named after a character in Alexander Pope's 1712 poem The Rape of the Lock, where the figure is described as a "dusky melancholy sprite." The name was suggested by John Herschel in 1852 at the request of Lassell. It also echoes the Latin word umbra, meaning shadow.
Why is Umbriel the darkest moon of Uranus?
Umbriel has a Bond albedo of only about 10%, making it the darkest of the Uranian moons. Bombardment by magnetospheric plasma on the trailing hemisphere deposits dark, carbon-rich residue, and the surface may be coated by a layer of dark material excavated by impacts or ancient volcanic activity.
What is the bright ring inside Umbriel's Wunda crater?
Wunda crater, about 131 kilometers in diameter, has a large ring of bright material on its floor. It may be an impact deposit or a concentration of nearly pure carbon dioxide ice that migrated across Umbriel's surface and accumulated in the relatively cold crater floor.
Has any spacecraft visited Umbriel?
Voyager 2 is the only spacecraft to have imaged Umbriel at close range, doing so during its flyby of Uranus in January 1986. It came no closer than 325,000 kilometers and mapped about 40% of the surface, with only 20% captured in enough detail for geological mapping.
What is Umbriel made of and does it have a core?
Umbriel has a density of 1.54 grams per cubic centimeter, indicating it is composed mainly of water ice with a non-ice component, likely rock and carbonaceous material, making up roughly 40% of its mass. It may be differentiated into a rocky core about 317 kilometers in radius surrounded by an icy mantle, though a subsurface ocean is considered unlikely to exist today.