March 29, 1997 in Nation/World

Comet Spews Key Molecules For Life

Associated Press

An analysis of the tons of organic molecules spewing out of Comet Hale-Bopp supports a theory that such celestial visitors may have delivered to Earth the chemical seeds of life billions of years ago.

In studies published Friday, scientists report on the composition and character of the dust and gas that are jetting out of Hale-Bopp as the comet hurtles away from the sun in its long journey back into deep space.

“Most of what we’re seeing is water ice, but there are also plenty of hydrocarbons and organic molecules that you would need for the genesis of life,” said Harold Weaver, a Johns Hopkins University astrophysicist.

“One of the major new findings from Hale-Bopp is all of these chemical molecules that are erupting from the comet as it heats from the sun,” Weaver said.

Hale-Bopp, as are other comets, is an aggregation of ice, dust and chemicals, sort of a “dirty snowball,” that remains frozen in the deep cold of outer space. Only when a comet approaches the sun does the ice warm up and send geysers of material streaming away as the distinctive comet tail.

But what makes Hale-Bopp different from other comets, Weaver said, is its size, 19 miles to 25 miles in diameter, and the fact that never before have sophisticated astronomical instruments gotten such a long look at a comet passing the sun.

“We’ve found that the surface of Hale-Bopp is an extremely violent place, with vents opening up as they are exposed to sunlight for the first time,” Weaver said.

The studies published Friday include observations started shortly after Hale-Bopp was discovered on July 23, 1995.

“Most of the stuff in comets are simple molecules, but they are the building blocks for life,” he said.

So far, researchers have identified at least 13 different chemical molecules, some of which could have been a starting point for the formation of amino acids, the basic molecules of life.

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