Newest meteorite find is most ancient
Scientists say a fragile, charcoal-like meteorite that plummeted on to a frozen Canadian lake last January may represent the most primitive solar system material yet studied.
This week's Science reports the analysis by Peter G. Brown at The University of Western Ontario, Canada and colleagues of the Tagish Lake meteorite.
"These data suggest that the Tagish Lake meteorite may be one of the most primitive solar system materials yet studied," writes the team.
Analysis of the meteorite's mineral composition and oxygen and carbon isotopes suggests that it may represent a new and more primitive class of carbonaceous chondrites - a rare type of ancient meteorite that contains many forms of carbon and organics, the basic building blocks of life.
Carbon analysis of the meteorite indicates that some of the carbon is contained in nanodiamonds, tiny particles of interstellar dust that were swirled into the solar nebula prior to the formation of the solar system. The meteorite may be richer in interstellar grains than any yet studied, according to the researchers.
Using numerous eyewitness accounts, photographs, videos, and satellite data of the meteorite's fiery and dramatic entrance into Earth's atmosphere, the researchers also calculated its origin, path through space, and average velocity.
Brown and colleagues suggest that the meteorite came from the middle of the asteroid belt with an orbit intersecting the Earth's orbit. The asteroid belt is located between Mars and Jupiter.
Fragments of the meteorite should aid scientists in their reconstruction of the early solar system environment, particularly the types and amounts of elements present in the original solar nebula.
The first recovered pieces of the Tagish Lake meteorite were recovered and remain frozen, which will help researchers examine the full range of volatiles and organic compounds on a primitive meteorite for the first time.
In a related article also published in Science, Jeffrey N. Grossmann of the US Geological Survey says that the Tagish Lake find is the most significant recovered meteorite fall since the Allende meteorite from Mexico and Murchison meteorite from Australia, both recovered in 1969.
Co-author Alan R. Hildebrand of the University of Calgary, Canada says that the best indication of the significance of the Tagish Lake recovery may be the receipt of dozens of requests from meteorite researchers around the world to study the new fall.