Past: Astrophysics – History of the Universe

Andrew E. Lange was a Goldberger Professor of Physics at California Institute of Technology, Pasadena, California.

Prof. Lange was known for the discovery of the large-scale spatial geometry of the universe being spatially flat, of its total mass-energy density having a “critical” value, and for major byproducts of this discovery.

He confirmed the existence of a negative-pressure dark energy pervading the universe; provided evidence for an inflationary epoch at the beginning of the universe, and measured the universe’s mean density, matter density and other cosmological parameters.

Together with Prof. Paolo De Bernardis (and in parallel to Paul Richards’ MAXIMA-1 experiment), Professor Lange led the BOOMERanG experiment which measured the angular sizes and amplitudes of the first few acoustic peaks in the cosmic microwave background radiation. These results led Lange and his colleagues to deduct the universe’s geometry and led to a number of consequent discoveries.

The publication of the BOOMERanG and MAXIMA data in 2000 provided the first undisputed evidence that the universe has a flat geometry. Additional analysis of the data implied that ordinary matter makes a small fraction of the cosmic mass density (5% at the present time). These results have been subsequently confirmed and carry important implications for fundamental physics.

The nature of most of the cosmic matter (known as “dark matter”) is actively being explored, and the flat geometry of the universe is believed to have originated from an early epoch of inflation, during which space curvature was erased by a prolonged period of vast expansion.

Prof. Lange also developed (together with astrophysicist James Bock) the spiderweb bolometers that made BOOMERanG’s and MAXIMA-1’s measurements possible, and that underlie other major cosmological and astronomical projects and instruments.

Prof. Lange was a member of the American Academy of Arts & Sciences and the National Academy of Sciences, and a fellow of the American Physical Society. His honors included the Balzan Prize in Observational Astronomy & Astrophysics. Prof. Lange was a Leverhulme Fellow, Cardiff, Wales; and 2003 California Scientist of the Year (co-recipient).