Date:04/02/2006 URL: http://www.thehindu.com/2006/02/04/stories/2006020403842200.htm

International

Deep secrets of the comets

LOS ANGELES: The Deep Impact space probe found the first evidence that comets have ice on their dusty surfaces, raising the possibility that comets may have delivered life-giving water to a primeval earth, scientists of the National Aeronautics and Space Administration (NASA) have said. The findings were reported in the online journal Science.

The copper-tipped space probe collided with comet Tempel 1 about 134 million km from the earth on July 4, setting off a celestial fireworks display and baring the comet's primordial interior.

Researchers analysing data recorded by the probe's mother ship concluded that the comet has three pockets of thin ice that cover 27,870 sq m of its 117 sq km. About 6 per cent of the ice is pure, while the rest is mixed with dust. "It's like a seven-acre skating rink of snowy dirt," said Peter Schultz, an investigator who co-wrote the Science report.

Scientists long ago concluded that comets are frozen, dusty remnants from the formation of our solar system 4.6 billion years ago. Some have theorised that comets smashing into the early Earth delivered primitive organic compounds and water that helped give rise to life. — AP