Andrew E. Lange (July 23, 1957 – January 22, 2010) was an astrophysicist and Goldberger Professor of Physics at the California Institute of Technology in Pasadena, California. Lange came to Caltech in 1993 and was most recently the chair of the Division of Physics, Mathematics and Astronomy. Caltech's president Jean-Lou Chameau called him "a truly great physicist and astronomer who had made seminal discoveries in observational cosmology".
Lange was born in Urbana, Illinois, and he grew up in Easton, Connecticut. Lange received his BA in physics from Princeton University in 1980, and the PhD in physics from University of California, Berkeley in 1987. He arrived at Caltech in 1993–1994 as a visiting associate, and was appointed Full Professor in 1994. He was appointed Goldberger professor in 2001, and senior research scientist at the Jet Propulsion Laboratory in 2006.
Lange's research interests focused on the Cosmic Microwave Background (CMB) and instrumentation for its study. The CMB is believed to be the light of the Big Bang, red-shifted from the visible into the sub-millimeter range by the cosmic expansion in the intervening 13.8 billion years. He developed a new generation of radio receivers for this study, and used them in a string of experiments to study the CMB.