Gamma ray burst causes extinction
12 April 2005
by Richard Conan-Davies
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It would seem that a gamma ray burst from a star within 6,000 light years from Earth may have wiped out 60% of life in the oceans some 450 million years ago. Brian Thomas from the Univeristy of Kansas, who led the computer simulation study with NASA, explained "that a gamma-ray burst may have caused the Ordovician extinction 450 million years ago, killing 60 percent of all marine invertebrates. Life was largely confined to the sea, although there is evidence of primitive land plants during this period. " According to their computer simulation, the main reason for the extinction is due the gamma rays reacting with nitrogen producing nitorgogen oxide which ends up destroying the ozone layer in the atmosphere within about 2 weeks. This would allow very intense UV light to kill many small creatures in the sea. |
 Plankton like this would be wiped out by UV radiation if there was no ozone layer. image: wikipedia.org |
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