Refining the Age of the Solar System

Researchers in the School of Earth and Space Exploration and the Center for Meteorite Studies recently placed better constraints on the age of the Solar System using samples from the CMS collection. SESE Graduate student Greg Brennecka, in conjunction with CMS Director Meenakshi Wadhwa, SESE/Department of Chemistry and Biochemistry Professor Ariel Anbar and colleagues from around the world, used calcium-aluminum rich inclusions (CAIs) in the Allende meteorite to find that a critical parameter used in Pb-Pb dating, the 238U/235U ratio, was not a constant as was previously believed. A variable 238U/235U ratio affects the accuracy of ages obtained by Pb-Pb dating by several million years. By establishing correct 238U/235U ratios for CAIs, which are believed to be the first objects to form in the Solar System, the timing of the earliest Solar System events is better constrained. The research results were published in Science Magazine online on December 31, 2009 and will appear in print in the January 22, 2010 issue. You can also read more about the research in the SESE press release.