image: This shows the crystal structure in the eucrite meteorite ALHA81001. The image represents a 0.5 by 0.35 mm section of the meteorite under backscatter electron microscopy. Isolated dark regions represent fine-grained, late-crystallizing material, which retains a recording of magnetic fields on the large asteroid Vesta. Large, light-toned lathes consist of pyroxene minerals and the fine scale light-gray/dark-gray banding indicates the long cooling timescale of the meteorite and implies the long-lived nature of magnetic fields on Vesta. This image relates to a paper that appeared in the Oct. 12, 2012, issue of Science, published by AAAS. The paper, by Roger Fu at Massachusetts Institute of Technology in Cambridge, Mass., and colleagues was titled, “An Ancient Core Dynamo in Asteroid Vesta.” view more
Credit: [Image courtesy of the MIT Paleomagnetism Laboratory and the MIT Experimental Petrology Laboratory]