Diamonds Found in Meteorites Means More May Be Floating in Galaxy
NEW YORK (AP) _ Trillions of diamonds so tiny that 20,000 equal the width of a hair have been found in meteorites, and scientists say they may give clues to the chemistry of stars and suggest ways to make tiny industrial gemstones.
″If you look up at the Milky Way, you may actually be seeing some light that is scattered by diamonds,″ said Roy Lewis, senior research associate at the University of Chicago.
Lewis and his colleagues have found trillions of the tiny diamonds in four meteorites, and they say the diamonds may have formed in the atmosphere of a dying star before the solar system was born 4.5 billion years ago.
The diamonds could be among the oldest things on Earth, Lewis said.
They may yield clues about the chemistry of stars, and learning how they formed could suggest better ways of manufacturing tiny diamonds for industrial purposes, he said. But ″in terms of something to put on your wife’s finger, they’re of absolutely no value at all,″ he said.
Lewis reported the discovery today in the British journal Nature along with Edward Anders and others at the school and Eric Steel of the National Bureau of Standards.
The new find is ″surprising and interesting,″ said John Wood, staff scientist at the Harvard-Smithsonian Center for Astrophysics. While diamonds have been found before in meteorites, they were formed relatively recently by the shock of impact, he said in a telephone interview.
Wood said the new report made him ″quite sure″ the newly found diamonds are older than the sun.
Lewis said researchers never expected to find diamonds when they started investigating a stone-like meteorite that plunged into a Mexican cornfield in 1969.
They were studying carbon dust in the meteorite, and when a laboratory procedure turned a sample from black to white, ″our basic reaction was, ’Oh damn,‴ said Lewis. Researchers thought the procedure had dissolved the carbon they wanted to study.
But tests showed the white residue was carbon. It contained an unusual combination of forms of the gas xenon, indicating that it came from outside the solar system.
Researchers finally identified the residue as diamond dust, so fine that a row of 20,000 grains would be about as wide as a human hair.
The researchers also found diamonds in three other meteorites, Lewis said. Tests showed that all four meteorites are as old as the solar system and that the embedded diamonds did not form as a result of collisions, he said.
The diamonds may have formed in the upper atmosphere of a star in the late ″red giant″ stage, where the temperature and abundance of hydrogen could encourage diamonds to form as carbon gas condenses, he said.
Recent Japanese and Russian research has shown that such conditions can lead to diamond formation, he said. Diamonds on Earth form instead under great pressure underground.
Diamonds formed by the star could have been blown into the cosmos by the ″stellar wind,″ an outpouring of matter from the star, he said. Later, when the star exploded in a supernova, its chemical elements may have struck the wandering diamonds and become embedded, he said.
So the diamonds would become essentially tiny capsules that retain the chemical samples from an exploding star, an intriguing possibility for study, he said.