'Deathstar' has Earth in its sights


A spectacular, rotating binary star system is a ticking time bomb, ready to throw out a searing beam of high-energy gamma rays – and Earth may be right in the line of fire.

Astronomers at the University of Sydney, in Australia, first discovered the unusual and beguilingly beautiful star system eight years ago in the Constellation Sagittarius. One member of the pair is a highly unstable star known as a Wolf-Rayet, thought to be the final stage of stellar evolution to precede a cataclysmic supernova explosion.

"When it finally explodes as a supernova, it could emit an intense beam of gamma rays coming our way", said Peter Tuthill, lead researcher of the team who report their findings in the current Astrophysical Journal.

Though the risk may be remote, there is evidence that gamma ray bursts have swept over the planet at various points in Earth's history with a devastating effect on life.

A 2005 study showed that a gamma-ray burst originating within 6,500 light years of Earth could be enough to strip away the ozone layer and cause a mass extinction. Researchers led by Adrian Melott at the University of Kansas in Lawrence, U.S., suggest that such an event may have been responsible for a mass extinction 443 million years ago, in the late Ordovician period, which wiped out 60 per cent of life and cooled the planet.

Further research would be required to determine if we are exactly in line with the axis of the system – but even if we are, we probably still have hundreds of thousands of years to come up with a solution, said Tuthill.

We can not repel fire power of that magnitude.

No comments: