'Comet disaster caused nuclear winter in dark ages'

 A "nuclear winter" that plunged people into starvation 1,500 years ago
 may have been caused by a comet colliding with Earth.

 Astronomers at Cardiff University say a 6th century impact caused crop
 failures, widespread starvation and summer frosts.

 The team has studied evidence from tree rings which suggests the Earth
 underwent a series of very cold summers around 536-540AD.

 Historical references from the period, known as the Dark Ages, tell of
 crop failures and summer frosts, researchers said.

 Scientists in the School of Physics and Astronomy believe this was caused
 by a comet hitting the earth and exploding in the upper atmosphere.

 Dr Derek Ward-Thompson, who supervised the project, said: "One of the
 exciting aspects of this work is that we have re-classified the size of
 comet that represents a global threat.

 "This work shows that even a comet of only half a kilometre in size could
 have global consequences. Previously nothing less than a kilometre across
 was counted as a global threat.

 "If such an event happened again today, then once again a large fraction
 of the Earth's population could face starvation."

 Debris from the "giant explosion" would have enveloped the planet in soot
 and ash, blocking out the sunlight and causing the very cold weather,
 scientists said.

 Ananova

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 Early extinction
 www.perceptions.couk.com/thumlate.txt

 Meteor Impact Database
 www.unb.ca/passc/ImpactDatabase/

 Terrestrial Impact Craters
 www.solarviews.com/eng/tercrate.htm

 Reclassification
 www.perceptions.couk.com/uef/thump.txt

 Reclassification
 www.perceptions.couk.com/uef/thump3.txt

 Higher Risk
 www.perceptions.couk.com/uef/thump7.txt

 A plea
 www.perceptions.couk.com/uef/complasens.txt

 Calculate the mega-tonnage odds per year
 www.perceptions.couk.com/chance.txt  

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Our crowded Solar System

http://cfa-www.harvard.edu/iau/lists/OuterPlot.html

http://cfa-www.harvard.edu/iau/lists/InnerPlot.html

http://cfa-www.harvard.edu/iau/lists/InnerPlot2.html

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