Thomas J. Ahrens received his B.S. from the Massachusetts Institute of Technology in 1957, his M.S. from Caltech in 1958, and his Ph.D. from Rensselaer Polytechnic Institute in 1962. He was a geophysicist with the Pan American Petroleum Corporation from 1958-1959, worked as a Second Lieutenant for the U.S. Army in the Ballistics Research Laboratory from 1959-1960, and was the Head of the Geophysics Section in the Poulter Laboratory of the Stanford Research Institute from 1962-1967. He became an Associate Professor of Geophysics at Caltech in 1967 and Professor of Geophysics in 1976. From 1996-2001 he was the W.M. Keck Professor of Earth Sciences and then Fletcher Jones Professor of Geophysics, Emeritus in 2005. He published more than 375 papers, owns 3 U.S. Patents, and received numerous honors and awards for his research. He was a member of the U.S. National Academy of Sciences, the American Academy of Arts and Sciences and a Foreign Associate of the Russian Academy of Sciences. He won the 1995 Arthur L. Day Medal of the Geological Society of America, the 1996 Harry H. Hess Medal of the American Geophysical Union, the 1997 Barringer Medal of the Meteoritical Society, and had an asteroid named after him.

His research encompassed a wide range of geophysical disciplines, including the dynamic properties of minerals and other materials, the effects of impacts on minerals, Earth and planetary crusts, shock temperatures and melting, planetary impacts, and the thermodynamics of Earth materials. He supervised more than 30 graduate students and more than 15 postdocs and visiting associates.

(Contributed by Reinhard Boehler)