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Астронет: Астрономическая картинка дня Таинственный темный спутник Урана Умбриэль http://variable-stars.ru/db/msg/1161757/eng |
Credit & Copyright: NASA, Voyager 2
Explanation:
Why is Umbriel so dark? This dark moon reflects only half the light of other
Uranus' moons such as
Ariel. And what is that bright ring at the top?
Unfortunately, nobody yet knows. These questions presented themselves when
Voyager 2
passed this satellite of Uranus in January 1986.
Voyager found an old surface with unusually large craters, and determined
Umbriel's composition to be about half ice and half rock.
Umbriel
is the fourth largest and third most distant of Uranus' five
large moons. Umbriel was discovered in 1851 by
William
Lassell.
Latest Comet Hyakutake images:
APOD Hyakutake Archive,
JPL,
Fayetteville
Observer-Times,
NASA's Night of
the Comet,
ICSTARS,
Jerry Lodriguss,
ScienceWeb,
Crni Vrh Obs.,
Cent. Mich. U.
Authors & editors:
Robert Nemiroff
(MTU) &
Jerry Bonnell
(USRA)
NASA Web Site Statements, Warnings,
and Disclaimers
NASA Official: Jay Norris.
Specific
rights apply.
A service of:
LHEA at
NASA /
GSFC
& Michigan Tech. U.