Gamma-ray bursts `could end life on Earth`
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Last Updated: Sunday, October 09, 2011, 16:43
  
London: Gamma-ray bursts, massive explosions on the other side of the galaxy, could end life on Earth, say planetary scientists.

A new theory claims that the explosions, thought to occur when two stars collide, releases tons of high-energy gamma-ray radiation into space, finally leading to the end of life on planet Earth.

The scientists have already found that such blasts are contributing to the depletion of the Earth's ozone layer. Disruption of the ozone layer lets ultraviolet light filter down to surface of Earth where it can change organisms by mutating their genes.

Now, they are beginning to connect the timing of these gamma-ray bursts to extinctions on Earth that can be dated through the fossil record.

"We find that a kind of gamma-ray burst -- a short gamma-ray burst -- is probably more significant than a longer gamma-ray burst," lead researcher Brian Thomas of Washburn University was quoted by 'Livescience.com' as saying.

He added: "The duration is not as important as the amount of radiation."

It is thought to be the first time the scientists have connected the timing of these gamma-ray bursts to extinctions on Earth that can be dated through the fossil record.

There are two types of gamma-ray bursts -- a longer, brighter burst and a "short-hard" burst, which lasts less than a second but seems to give off more radiation than a longer burst.

If such a burst were to happen inside the Milky Way, its effects on Earth would be much longer lasting. The short bursts may be caused by fender-benders between stars, such as dense neutron stars or black holes colliding.

The researchers were able to estimate such collisions happen about once every 100 million years in a galaxy. That means Earth would have been hit by several over the course of its history.

PTI


First Published: Sunday, October 09, 2011, 16:43


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