Supernova explosion unlikely to harm life on Earth
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Last Updated: Saturday, December 17, 2011, 11:20
  
Washington: An erroneous doomsday theory predicts that year 2012 may experience a supernova explosion and the incredible amounts of energy resulting from it – as much as the sun creates during its entire lifetime– may harm life on Earth.

However, astronomers are confident that it will not prove detrimental for life on earth, given the vastness of space and the long times between supernovae.

They can say with certainty that there is no threatening star close enough to hurt Earth.

Astronomers estimate that, on average, about one or two supernovae explode each century in our galaxy. But for Earth’s ozone layer to experience damage from a supernova, the blast must occur less than 50 light-years away. All of the nearby stars capable of going supernova are much farther than this.

Any planet with life on it near a star that goes supernova would indeed experience problems. X- and gamma-ray radiation from the supernova could damage the ozone layer, which protects us from harmful ultraviolet light in the sun’s rays. The less ozone there is, the more UV light reaches the surface.

At some wavelengths, just a 10 percent increase in ground-level UV can be lethal to some organisms, including phytoplankton near the ocean surface. Because these organisms form the basis of oxygen production on Earth and the marine food chain, any significant disruption to them could cascade into a planet-wide problem.

Another explosive event, called a gamma-ray burst (GRB), is often associated with supernovae. When a massive star collapses on itself or less frequently, when two compact neutron stars collide -- the result is the birth of a black hole.

Astronomers estimate that a gamma-ray burst could affect Earth from up to 10,000 light-years away with each separated by about 15 million years, on average. So far, the closest burst on record, known as GRB 031203, was 1.3 billion light-years away.

As with impacts, our planet likely has already experienced such events over its long history, but there’s no reason to expect a gamma-ray burst in our galaxy to occur in the near future, much less in December 2012.

ANI


First Published: Saturday, December 17, 2011, 11:16


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