Scientists are agog over the brightest exploding star in 383 years

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Although many scientists now lean toward the theory that dinosaurs were wiped out 65 million years ago by the impact on earth of a large comet or asteroid, some experts until recently were suggesting that radiation from a nearby supernova might have been the culprit. No evidence exists that a supernova has ever flared close enough to earth to destroy life. Still, if one should go off within ten to 20 light-years away, says Radio Astronomer Gerrit Verschuur, "we would have a problem. Everything would be destroyed by blasts of X rays, ultraviolet radiation and cosmic rays." Radiation from an expanding supernova even as distant as 50 light-years, he says, would pack a tremendous wallop, probably destroying the atmosphere's protective ozone layer and causing harmful mutations. Such a supernova could alter the course of biological evolution, perhaps wiping out entire species.

As astronomers survey the nearest stars, however, they see no apparent candidates for an imminent supernova. One favorite in the supernova category is Betelgeuse, the red supergiant clearly visible at the shoulder of the constellation Orion, the Hunter. That monster star is 650 light-years away, out of harm's way, but should provide a spectacular show when and if it expires.

Indeed, although the experts consider it unlikely, Betelgeuse may have already died of gravitational collapse -- around the time of Columbus, for example, or Galileo or Napoleon. If so, the light generated by that explosion * is on its way, well along on its 650-year journey to earth, bearing evidence that the red supergiant has been consumed in a cosmic catastrophe. But for now, astronomers aiming their sophisticated instruments into the night sky would be no more aware of the event than their primitive ancestors were of 1987A, when, 170,000 years ago, they stared fleetingly at the Large Magellanic Cloud.

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Description: Relationships between Milky Way Galaxy, Andromeda Galaxy and Large Magellanic Cloud.

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Credit: TIME Diagrams by Joe Lertola


Description: How a binary system goes supernova.

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Credit: TIME Diagrams by Joe Lertola


Description: How a supergiant star goes supernova.

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