Nobel Foundation · Public domain

Arrived in New York's Lower East Side as an infant from a Polish-Jewish family in Austria-Hungary and grew up to develop the resonance method for measuring the magnetic properties of atomic nuclei, work that won him the 1944 Nobel Prize in Physics and became the technical foundation for magnetic resonance imaging. He also helped develop the cavity magnetron used in wartime radar, and later argued, as a science advisor to postwar presidents, for civilian control of the technology physicists like him had helped unleash.