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Last Updated: Friday, 5 October 2007, 11:06 GMT 12:06 UK
Mirrors 'could deflect' asteroids
Mirrors tackling an asteroid
Mirrors harnessing the Sun's energy take on an asteroid
Flying mirrors could save earth from a catastrophic asteroid collision, researchers have claimed.

Up to 5,000 mirrors would be used to focus a beam of sunlight on to the asteroid, melting the rock and altering its orbital path away from earth.

The announcement came after a team at the University of Glasgow compared nine different methods of deflecting near earth objects - asteroids and comets.

A 100m asteroid hits the earth roughly every century.

The research team compared the mirror technique with eight others, including a nuclear explosion.

Scientist fear the risk of flying debris from an over aggressive nuclear explosion.

Our studies show that this technology is genuinely feasible
Dr Massimiliano Vasile
University of Glasgow

Orbiting mirrors would be used to focus sunlight on an area of the asteroid - heating the rock to around 2,100 degrees Celsius.

This would create a thrust which would nudge the asteroid off course.

The team found that the orbit of an asteroid 150m across could be sufficiently modified by a swarm of 100 mirrors in a few days.

For an asteroid on the scale of that which is believed to have wiped out the dinosaurs, a 5,000-strong fleet of spacecraft would need to focus a beam on the surface for three or more years.

Dr Massimiliano Vasile, who led the project, said: "Asteroid impacts are a real threat.

"The Tunguska explosion in 1908 devastated an area bigger than Greater London.

"With only 10 spacecraft flying in formation, each with a 20m mirror, we could deflect a similar size asteroid into a safe orbit in about six months.

"Our studies show that this technology is genuinely feasible."

The results were unveiled at the Jodrell Bank observatory in Cheshire as part of celebrations for the 50th anniversary since the launch of Soviet satellite Sputnik 1, which marked the start of the space age.

Successful launch for Nasa probe
27 Sep 07 |  Science/Nature
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05 Sep 07 |  Science/Nature
UK plan to track asteroid threat
31 Aug 07 |  Science/Nature


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