110px|Triton
Triton is the largest moon of the planet Neptune, discovered on
October 10, 1846, by William Lassell. It is the only large moon in the
Solar System with a retrograde orbit, which is an orbit in the opposite
direction to its planet's rotation. At 2700 km in diameter, it is the
seventh-largest moon in the Solar System. Because of its retrograde
orbit and composition similar to Pluto's, Triton is thought to have
been captured from the Kuiper belt. Triton consists of a crust of
frozen nitrogen over an icy mantle believed to cover a substantial core
of rock and metal. The core makes up two-thirds of its total mass.
Triton has a mean density of 2.061 g/cm3 and is composed of
approximately 15–35% water ice. Triton is one of the few moons in the
Solar System known to be geologically active. As a consequence, its
surface is relatively young, with a complex geological history revealed
in intricate and mysterious cryovolcanic and tectonic terrains. Part of
its crust is dotted with geysers believed to erupt nitrogen. (more...)
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<http://en.wikipedia.org/wiki/Triton_%28moon%29>
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Today's selected anniversaries:
451:
The Council of Chalcedon, the fourth ecumenical council in
Christianity, opened. It repudiated the Eutychian doctrine of
monophysitism, and set forth the Chalcedonian Creed.
<http://en.wikipedia.org/wiki/Council_of_Chalcedon>
1076:
Demetrius Zvonimir, the last native king who exerted any real power
over the entire Croatian state, was crowned.
<http://en.wikipedia.org/wiki/Demetrius_Zvonimir_of_Croatia>
1897:
Composer Gustav Mahler was appointed the director of the Vienna Court
Opera.
<http://en.wikipedia.org/wiki/Gustav_Mahler>
1967:
Marxist revolutionary and guerrilla leader Che Guevara was captured
near La Higuera, Bolivia.
<http://en.wikipedia.org/wiki/Che_Guevara>
2001:
At Linate Airport in Milan, Italy, Scandinavian Airlines Flight SK686
collided on take-off with a Cessna Citation II business jet, killing
118 people.
<http://en.wikipedia.org/wiki/Linate_Airport_disaster>
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Wiktionary's word of the day:
stylite (n):
(historical) A Christian ascetic who lived alone on top of a tall
pillar
<http://en.wiktionary.org/wiki/stylite>
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Wikiquote quote of the day:
One always feels that a merely educated man holds his philosophical
views as if they were so many pennies in his pocket. They are separate
from his life. Whereas with a cultured man there is no gap or lacuna
between his opinions and his life. Both are dominated by the same
organic, inevitable fatality. They are what he is.
--John Cowper Powys
<http://en.wikiquote.org/wiki/John_Cowper_Powys>