The Kreutz Sungrazers are a family of comets, characterized by orbits
which take them extremely close to the Sun at perihelion. They are all
believed to originate from the fragmentation of one very large comet
several centuries ago, and are named for the astronomer Heinrich
Kreutz, who first demonstrated that they were related. Several members
of the Kreutz family have become Great Comets, occasionally visible
near the Sun in the daytime sky. The most recent of these was Comet
Ikeya-Seki in 1965, which may have been one of the brightest comets in
the last millennium. Many hundreds of smaller members of the family
have been discovered since the launch of the SOHO satellite in 1995.
Some are just a few metres across; none has survived its perihelion
passage. Amateur astronomers have been very successful at discovering
Kreutz comets in the data available in real time via the Internet.
Read the rest of this article:
http://en.wikipedia.org/wiki/Kreutz_Sungrazers
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Today's selected anniversaries:
1609:
Bohemia was granted freedom of religion.
(
http://en.wikipedia.org/wiki/freedom_of_religion)
1785:
The dollar was unanimously chosen as the money unit for the United
States. This was the first time a nation had adopted a decimal
currency system.
(
http://en.wikipedia.org/wiki/United_States_dollar)
1885:
Louis Pasteur successfully tested his vaccine against rabies on Joseph
Meister.
(
http://en.wikipedia.org/wiki/Louis_Pasteur)
1887:
David Kalakaua, monarch of the Kingdom of Hawaii, was forced at
gunpoint, at the hands of Americans, to sign the Bayonet Constitution
giving Americans more power in Hawaii while stripping Hawaiian
citizens of their rights.
(
http://en.wikipedia.org/wiki/Bayonet_Constitution)
1957:
Althea Gibson won the Wimbledon championships, becoming the first
black athlete to do so.
(
http://en.wikipedia.org/wiki/Althea_Gibson)
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Wikiquote of the day:
"I have not yet begun to fight!" -- John Paul Jones
(
http://en.wikiquote.org/wiki/John_Paul_Jones)