Caltech Mourns the Passing of Andrew Lange

Dr. Andrew Lange, the Marvin L. Goldberger Professor of Physics at Caltech, passed away Friday, January 22, 2010.

Lange had been at Caltech since 1993. He graduated from Princeton University with his BA in 1980 and received his PhD from UC Berkeley in 1987. He first came to the Institute as a visiting associate in 1993-94, was appointed a full professor in 1994, and was named the Goldberger Professor in 2001. In 2006 he was named a senior research scientist at the Jet Propulsion Laboratory and in 2008 was appointed chair of the Division of Physics, Mathematics and Astronomy. He had recently resigned from his chairmanship of the division.

The principal focus of Lange's research was the Cosmic Microwave Background (CMB)-a gas of thermal radiation left over from the Big Bang-that filled the entire universe. He developed a new generation of radio-frequency detectors and led a string of experiments that employed this novel technology to study the CMB. He is perhaps best known for co-leading the BOOMERanG experiment, the first experiment to image the CMB with sufficiently high fidelity and angular resolution to determine that the spatial geometry of the universe is flat. The data further allowed precise measurement of the age of the universe and the abundance of the dark matter known to hold galaxies together. The data also supported previous measurements that suggested that the cosmological expansion is actually accelerating, implying either a violation of Einstein's general relativity or that the Universe is filled with "dark energy," some exotic new negative-pressure fluid. BOOMERanG also confirmed the predictions of inflation, an ambitious theory that aims to explain the very earliest fraction of a nanosecond after the Big Bang.

Lange's subsequent work has improved upon these measurements and aimed also to detect the primordial gas of gravitational waves predicted by inflation through their effect on the CMB polarization. Lange was also one of the leaders of the recently launched Planck satellite, a collaboration between US and European scientists that aims to image the CMB with unprecedented precision.

Lange was a member of the American Academy of Arts and Sciences, the National Academy of Sciences, and the American Physical Society. Lange and Dr. Saul Perlmutter (from the Lawrence Berkeley National Laboratory) were jointly named the 2003 California Scientist of the Year for their seminal contributions to cosmology. Lange shared the 2006 Balzan Prize for Observational Astronomy and Astrophysics with Paolo de Bernardis (of the University of Rome), his BOOMERanG coleader. The two shared the 2009 Dan David Prize with Paul Richards, a coleader of the parallel MAXIMA experiment.

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