90377 Sedna is a trans-Neptunian object currently about three times as
far from the Sun as Neptune. For the majority of its orbit it is the
most distant known object in the Solar System other than long-period
comets. Roughly two-thirds the size of Pluto, Sedna is hypothetically
large enough to be rounded by its own gravity, and thus would qualify
as a dwarf planet under current definitions. However, its distance
makes determining its shape difficult. Spectroscopy has revealed that
Sedna's surface composition is similar to that of some other
trans-Neptunian objects, being largely a mixture of water, methane, and
nitrogen ices with tholins. Its surface is one of the reddest in the
Solar System. Its exceptionally long and elongated orbit, taking
approximately 12,000 years to complete, and distant point of closest
approach to the Sun have led to much speculation as to its origin.
Astronomer Mike Brown, who co-discovered Sedna in 2003, believes it to
be the most scientifically important trans-Neptunian object found to
date, as understanding its peculiar orbit is likely to yield valuable
information about the origin and early evolution of the Solar System.
Read the rest of this article:
<http://en.wikipedia.org/wiki/90377_Sedna>
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Today's selected anniversaries:
1910:
Aviator Eugene Burton Ely performed the first takeoff from a ship,
flying from a makeshift deck on the USS Birmingham in Hampton Roads,
Virginia, US.
<http://en.wikipedia.org/wiki/Eugene_Burton_Ely>
1940:
World War II: Coventry Cathedral and much of the city centre of
Coventry, England, were destroyed by the German Luftwaffe during the
Coventry Blitz.
<http://en.wikipedia.org/wiki/Coventry_Blitz>
1971:
NASA's Mariner 9 reached Mars, becoming the first spacecraft to orbit
another planet.
<http://en.wikipedia.org/wiki/Mariner_9>
1984:
Cesar Climaco, mayor of Zamboanga City, the Philippines, was
assassinated.
<http://en.wikipedia.org/wiki/Cesar_Climaco>
1990:
Germany and Poland signed the German–Polish Border Treaty, confirming
their border at the Oder-Neisse line, which was originally defined by
the Potsdam Agreement in 1945.
<http://en.wikipedia.org/wiki/Oder-Neisse_line>
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Wiktionary's word of the day:
legato (adv):
(music) Smoothly; in a connected manner
<http://en.wiktionary.org/wiki/legato>
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Wikiquote quote of the day:
Call me Ishmael. Some years ago — never mind how long precisely —
having little or no money in my purse, and nothing particular to
interest me on shore, I thought I would sail about a little and see the
watery part of the world. It is a way I have of driving off the spleen
and regulating the circulation.
--Herman Melville
<http://en.wikiquote.org/wiki/Herman_Melville>
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