“World’’s biggest laser pointer” to unravel mystery behind birth and death of stars

January 5th, 2009 - 3:08 pm ICT by ANI  

Sydney, Jan 5 (ANI): Astronomers are using what they say is the “world’’s biggest laser pointer” to unravel the mystery behind the birth and death of stars.
According to a report in the Sydney Morning Herald, the international team of astronomers is led by Stuart Ryder from the Anglo-Australian Observatory, near Coonabarabran.
“We are using a laser 10,000 times more powerful than the ones you can have in NSW (New South Wales),” said Ryder, who is seeking to explain a mystery threatening to undermine science’’s understanding of how stars are born and how they die.
The mystery is that about 250 million light years away, two galaxies are colliding, slamming massive clouds of gas together to give birth to new stars.
Large stars end their lives in massive explosions called supernovae. Inside the colliding galaxies, however, there is an absence of any stellar death.
“We are seeing only a few per cent of the supernovae we should be seeing,” said Dr Ryder. “There should be many, many more stars dying,” he added.
One possible explanation is that science’’s understanding of stars is wrong.
Another is that dying stars, “like cockroaches dying unseen under the couch”, are easily missed.
To discover which is right, Dr Ryder is using sophisticated new technology called laser guide star adaptive optics at the giant Gemini telescope, atop Hawaii’’s 4200-metre Mauna Kea.
Adaptive optics allows astronomers to produce extraordinarily sharp images by canceling the blurring effect of Earth’’s atmosphere, which also makes stars twinkle.
A 10-watt laser is blasted 90 kilometers into the sky, causing atoms to glow, creating “an artificial star”.
The atmosphere also blurs the artificial star.
“We know what shape it ought to be,” said Dr Ryder, adding that by watching it twinkle, they can plot the atmospheric distortions.
Computers then use the information to manipulate the telescope’’s galactic observations, removing the distortions.
By comparing Gemini images snapped this year with ones shot by the Hubble telescope in 2004, Dr Ryder’’s team, including Finnish and South African scientists, has already spotted one previously unseen supernova.
With only a third of the two-year project completed, he expects to find at least a dozen more.
“It shows we are on the right track,” said Ryder. (ANI)

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