The rings of Uranus were discovered on March 10, 1977 by James L. Elliot,
Edward W. Dunham, and Douglas J. Mink. Two additional rings were discovered
in 1986 by the Voyager 2 spacecraft, and two outer rings were found in
2003–2005 by the Hubble Space Telescope. Additional faint dust bands and
incomplete arcs may exist between the main rings. The rings are extremely
dark—the bond albedo of the rings' particles does not exceed 2%. They are
likely composed of water ice with the addition of some dark
radiation-processed organics. The majority of Uranus's rings are opaque and
only a few kilometres wide. The ring system contains little dust overall; it
consists mostly of large bodies 0.2–20 m in diameter. The relative lack of
dust in the ring system is due to aerodynamic drag from the extended Uranian
exosphere—corona. The rings of Uranus are thought to be relatively young, at
not more than 600 million years. The mechanism that confines the narrow
rings is not well understood. The Uranian ring system probably originated
from the collisional fragmentation of a number of moons that once existed
around the planet. After colliding, the moons probably broke up into
numerous particles, which survived as narrow and optically dense rings only
in strictly confined zones of maximum stability.
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Today's selected anniversaries:
An expedition led by English explorer James Cook reached Christmas Island,
the largest coral atoll in the world.
The Treaty of Ghent was signed in Ghent, present-day Belgium, ending the War
of 1812 between the United Kingdom and the United States.
Six Confederate veterans of the American Civil War founded the Ku Klux Klan,
which would later become a white supremacist group.
Canadian inventor Reginald Fessenden transmitted the first radio broadcast,
which included his playing a song on the violin and reading a passage from
Cyclone Tracy struck Darwin, Australia, eventually destroying more than 70
percent of the city.
Wiktionary's word of the day:
workshop (n) 1. A small room where things are manufactured, or light
industrial work is done.
2. A brief intensive course of education for a small
Wikiquote quote of the day:
Nobody can conceive or imagine all the wonders there are unseen and
unseeable in the world. You tear apart the baby's rattle and see what makes
the noise inside, but there is a veil covering the unseen world which not
the strongest man, nor even the united strength of all the strongest men
that ever lived, could tear apart. Only faith, fancy, poetry, love, romance,
can push aside that curtain and view and picture the supernal beauty and
glory beyond. Is it all real? Ah, Virginia, in all this world there is
nothing else real and abiding. No Santa Claus! Thank God! he lives, and he
lives forever. A thousand years from now, Virginia, nay, ten times ten
thousand years from now, he will continue to make glad the heart of
--Francis Pharcellus Church