Far-out find: Diamonds in space

April 02, 1993|By San Francisco Chronicle

Space agency scientists have discovered to their astonishment that dark clouds of matter far out in the Milky Way are strewn with countless tiny diamonds whose existence challenges current theories about the life and death of stars and planets.

The diamonds pose no threat to jewelry stores on Earth, because they are so microscopically small that more than 2 million of them would fill barely an inch of space on a jeweler's JTC shelf, the scientists say.

The dense clouds of gas and dust where they were detected are wholly different in character from more diffuse and rarefied regions of space nearby, and they are in fact the nurseries where newborn stars are formed.

But deep within those clouds astronomers and space-gazing chemists have found evidence that billions of tons of diamond molecules have been created, by mechanisms as yet unknown, long before the solar system condensed from its primordial spinning disk of matter.

The scientists, based at NASA's Ames Research Center in Mountain View, Calif., unexpectedly found the diamonds while they were scanning a half-dozen of the galaxy's distant dark clouds through an infrared telescope atop Mauna Kea on the island of Hawaii.

They had expected to detect organic molecules, like methanol and other waxy hydrocarbons, which are common in the more diffuse regions of space near the dark clouds. But, as they first reported in November in the Astrophysical Journal, their analysis of the telescope's spectroscopic readings showed to their surprise and delight that they had instead found the clouds were littered with billions of carbon molecules whose atoms were bonded together in structures identical to the precious diamonds mined on Earth.

The research team was headed by scientists Louis Allamandola and Scott Sandford, and included Xander Tielens, a Dutch scientist at Ames, and Tom M. Herbst, a German astronomer at the University of Hawaii.

In the journal Science, the scientists describe the challenge their discovery poses to traditional theories that the galaxy's dense and diffuse clouds constantly mix and merge, as stars, planets and comets are formed.

The infinitely tiny diamonds apparently exist only in the dense dust clouds, but not at all in the less dense clouds of the galaxy, according to Mr. Allamandola and Mr. Sandford.

And because of that distinction, they and their colleagues say, it appears that the two types of clouds always remain separated rather than merging.

Thus, revisions will be needed in current theories that hold that over long stretches of time the star-forming clouds condense, give birth to stars, then dissipate as the stars die out, and then form anew in eternally repeating cycles.

"It means that all our models of galaxy evolution are flawed," Mr. ++ Sandford said.

Five years ago, a University of Chicago team found similar microscopic diamond grains embedded in ancient meteorites that had formed far out in interstellar space long before the birth of the solar system.

Those diamonds, too, posed a puzzle, because on Earth they are formed deep underground by intense pressure.

Mysteries surround the origin of the "microdiamonds," too. They may have been created by tremendously powerful shock waves that are generated when stars explode as supernovas, the Ames team speculates. Or perhaps they formed when aging stars surrounded by dusty shells of carbon -- known as red giants -- burned up their thermonuclear fuel and collapsed in an inferno.

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