A new study suggests that giant stars may not be necessary for supernovae.

This is a bit discomforting. Nearby supernovae are suspects in a number of past extinction events. Scientists think that a gamma-ray burst from a supernova may have been responsible for the Ordovician extinction which killed off 60% of all marine species 450 million years ago. A supernova has also been suspected in the extinction of the mammoth just 13,000 years ago.

The gamma-ray burst from a supernova is not likely to kill off organisms from direct biological effects unless the supernova is very close by (unrealistically close). A gamma burst could damage the ozone layer, however, causing species extinctions due to increases in ultraviolet radiation. It could also trigger changes in the Earth’s climate that lead to a new ice age.

Until now, scientists thought they knew which stars were candidates for supernovae. If that is changing, we may need to take another look at the stars in our own neighborhood. The risks may be greater than we think.

Still, we’re probably at far greater risk, individually and collectively, from the star which is closest to us and sustains our lives: the sun. A solar superstorm could damage or destroy power grids, pipelines, and communication satellites, plunging us back into the dark ages. Even a much smaller storm could endanger the lives of space travelers, including spaceflight participants on the suborbital vehicles many of us hope to be flying in a few years. Fortunately, there steps that can be taken to understand and prepare for bad space weather. Citizen scientists can help improve space-weather forecasting by participating in the Royal Greenwich Observatory’s Solar Storm Watch.

Written by Astro1 on March 21st, 2012 , Planetary Defense

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