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Star dust in the sky with diamonds.

Star dust in the sky with diamonds

Diamond dust, created within gasesescaping from a dying star, may be strewn throughout space. The evidence for this startling picture is embedded in microscopic diamonds recently found for the first time within several types of meteorites. These diamonds are probably older than the solar system, say Edward Anders and Roy S. Lewis of the University of Chicago and their colleagues. Their report appears in the March 12 NATURE.

The group's initial goal was to identifythe fine-grained type of carbon contained in many primitive, stony meteorites. After a series of purification steps, the researchers ended up with a powdery, white residue. Tests showed that the powder consisted largely of tiny diamond grains, typically 50 angstroms in diameter, each of no more than a million or so carbon atoms arranged in a diamond lattice. Because these grains also carry traces of xenon gas having a distinctive proportion of isotopes, the researchers concluded that the diamonds must have come from outside the solar system and were not created in the shock generated when meteorites crash into the earth (SN: 6/13/81, p. 376).

Anders hypothesizes that the diamondswere probably created billions of years ago during the dying years of a red giant star. At that stage, the huge star would be losing enormous amounts of gas. That gas would expand and cool, causing materials such as carbon to condense. Centuries later, when the star finally exploded as a supernova, it would eject high-velocity ions, including charged xenon atoms, which would overtake the escaping diamond grains and become embedded in the dust. This debris might then have mixed with the material out of which the solar system was much later born.

"Diamonds may be made on an enormousscale in the universe,' says Anders. "This is what I find so mind-boggling.' Adding to the excitement, he says, is that materials scientists recently had developed a laboratory process for growing diamonds from low-pressure gases--before they had any indication that it also happens in outer space (SN: 8/23/86, p.118).

Materials scientists could learnsomething from the stars, says Anders. "Red giants are fairly well behaved and well understood,' he says. "You can look up the temperature, pressure and chemical composition of a red giant atmosphere and try to duplicate it in the laboratory.'
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Title Annotation:microscopic diamonds found in meteorites
Author:Peterson, Ivars
Publication:Science News
Date:Mar 14, 1987
Previous Article:Goodbye, Pioneer 9.
Next Article:A super-supercomputer.

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