Photo of Walter M. Elsasser

Walter M. Elsasser

  • National Medal of Science
  • Physical Sciences
For his fundamental and lasting contributions to physics, meteorology, and geophysics in establishing quantum mechanics, atmospheric radiation transfer, planetary magnetism and plate tectonics.

Until the mid-1940s, scientists struggled to understand the origin of the earth’s magnetic field. The work of German-born physicist Walter Elsasser helped unlock the mystery.rnrnElsasser’s “dynamo theory’’ suggested that rotating fluid within the earth’s core essentially was responsible for producing the magnetic field. Elsasser also pioneered studies of the magnetic orientation of minerals in rocks to probe the history of earth’s magnetic field.rnrnHis research also helped to establish theories on plate tectonics and continental drift, which sought to explain the shifting of continents across the earth, as well as electron scattering.rnrnElsasser earned a doctorate in quantum mechanics from the University of Gottingen in 1927, and during his long career held positions at several universities, including Princeton, Johns Hopkins and the California Institute of Technology. He became a United States citizen in 1940 and during World War II worked for the U.S. Signal Corps, where his work included research on electronics and the meteorological effects of radar use.rnrnElsasser, whose work also involved research in meteorology, biology and oceanography, was elected to the National Academy of Sciences in 1957.rnrnBy Robert Warren