image: Meteorites often have complex histories. Before they reach Earth, they have variously been subjected to massive, sometimes repeated impacts, altered by interaction with hot, aqueous fluids, heated, sometimes to extreme temperatures, by the decay of radionuclides, undergone intense and prolonged temperature oscillations in their orbits and rotation, or have been bombarded by both cosmic radiation and the unshielded rays of our sun. Passage through the Earth's atmosphere, however, is by far one of the most violent processes they undergo. The vast majority of the originally multi-ton bulk of the Sutter's Mill meteorite was burnt away during this passage. Here, the melted and recrystallized outer surface of the meteorite is shown magnified about 8,000x, using a scanning electron microscope at the Arkansas Nano-Bio Materials Characterization Facility at the University of Arkansas, Fayetteville. This image relates to a paper that appeared in the Dec. 21, 2012, issue of Science, published by AAAS. The paper, by Peter Jenniskens at SETI Institute in Mountain View, Calif., and colleagues was titled, "Radar-Enabled Recovery of the Sutter's Mill Meteorite, a Carbonaceous Chondrite Regolith Breccia." view more
Credit: Image courtesy of Robert Beauford, University of Arkansas