A meteorite's pristine origins.A rare, carbon-rich meteorite meteorite, meteor that survives the intense heat of atmospheric friction and reaches the earth's surface. Because of the destructive effects of this friction, only the very largest meteors become meteorites. Classification of MeteoritesNot until the early 19th cent. did scientists fully accept the fact that meteorites came to the earth from outer space. that fell into a frozen Canadian lake early last year (SN: 4/8/00, p. 235) ranks as the most pristine of such specimens ever found, report the researchers who conducted the first chemical analyses. The Taglish Lake meteorite is classified as a carbonaceous chondrite chondrite: see meteorite., one of the first group of meteorites to have formed in the solar system solar system, the sun and the surrounding planets, natural satellites, dwarf planets, asteroids, meteoroids, and comets that are bound by its gravity. The sun is by far the most massive part of the solar system, containing almost 99.9% of the system's total mass. The principal members of the sun's retinue are the eight major planets; other parts of the solar system are discussed in separate articles: see comet, asteroid, and meteor.. The rock contains buckyballs A molecule of carbon expected to have use in a variety of applications, especially in the medical field. Also known as "Fullerines" because the 60 atoms that make up their spherical molecule resemble Buckminster Fuller's geodesic domes, they are lighter than plastic and stronger than steel. They can also conduct heat and electricity. Buckyballs were identified in 1985 by three scientists who later received a Nobel prize for the discovery.--soccerball-shaped molecules made of carbon--filled with the inert gases helium and argon. The ratio of helium to argon that the scientists measured matches the ratio that astronomers calculate was present in the cloud of gas and dust that surrounded the young sun and provided the raw material for the planets. That finding indicates the Tagish Lake meteorite has preserved chemical elements that developed or accumulated early in the history of the solar system, according to chemist Sandra Pizzarello of Arizona State University in Tempe and her colleagues. They report their findings in the Sept. 21 SCIENCE. The presence of bucky-balls and other carbon molecules could hold clues to the chemical evolution that preceded life in the solar system. In contrast to the Murchison meteorite, another carbon-rich rock, the Taglish Lake object contains virtually no amino acids and only simple organic compounds. That could prove disappointing to scientists who had hoped to find in the meteorite a reservoir of materials essential to life, but the rock's chemical constituents "still might have contributed molecular precursors of biomolecules to the origins of life," says Pizzarello. |
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