Umbriel is the third-largest moon of Uranus. It was discovered on October 24, 1851, by William Lassell. Named after a character in the 1712 poem The Rape of the Lock by Alexander Pope, Umbriel is composed mainly of ice with a substantial fraction of rock. It may be differentiated into a rocky core and an icy mantle. Its surface, the darkest among Uranian moons, appears to have been shaped mostly by impacts, but the presence of canyons suggests early endogenic processes. This shows Umbriel may have undergone an early endogenically driven resurfacing event that erased its older surface. Covered by numerous impact craters reaching 210 km (130 mi) in diameter, Umbriel is the second-most heavily cratered satellite of Uranus after Oberon. Like all moons of Uranus, Umbriel likely formed from an accretion disk that surrounded the planet just after its formation. The only close study of Umbriel was conducted in January 1986 by Voyager 2, which captured images of about 40 percent of its surface during the spacecraft's flyby of Uranus.
Read more: <https://en.wikipedia.org/wiki/Umbriel_%28moon%29> _______________________________ Today's selected anniversaries: 1796: War of the First Coalition: The Battle of Schliengen was fought between the French and Austrian armies, who both claimed victory. <https://en.wikipedia.org/wiki/Battle_of_Schliengen> 1945: The Charter of the United Nations entered into force after being ratified by the five permanent members of the Security Council and a majority of the other signatories. <https://en.wikipedia.org/wiki/Charter_of_the_United_Nations> 1975: In protest against wage discrepancy and unfair employment practices, 90 percent of Iceland's female population went on strike for a day. <https://en.wikipedia.org/wiki/1975_Icelandic_women%27s_strike> 2003: The inaugural Afro-Asian Games opened in Hyderabad, with 2,040 athletes from 96 nations competing. <https://en.wikipedia.org/wiki/2003_Afro-Asian_Games> _____________________________ Wiktionary's word of the day: neoimperialism: (politics) A contemporary form of imperialism; modern imperialistic practices by a country, such as using influence and power to dominate smaller countries. <https://en.wiktionary.org/wiki/neoimperialism> ___________________________ Wikiquote quote of the day: Principles are universal — that is, they transcend culture and geography. They're also timeless, they never change — principles such as fairness, kindness, respect, honesty, integrity, service, contribution. Different cultures may translate these principles into different practices and over time may even totally obscure these principles through the wrongful use of freedom. Nevertheless, they are present. Like the law of gravity, they operate constantly. --Stephen Covey <https://en.wikiquote.org/wiki/Stephen_Covey> _______________________________________________ Wikipedia Daily Article mailing list. To unsubscribe write to: [email protected] Questions or comments? Contact [email protected]
