James Van Allen

Born on 7 September 1914 on a small farm near Mount Pleasant, Iowa, James Van Allen was a space scientist and pioneer in magnetospheric physics, best known for his discovery of Earth’s Van Allen radiation belts. After earning his PhD in nuclear physics from the University of Iowa in 1939, Van Allen worked as a research fellow at the Carnegie Institution of Washington. In April 1942 he joined the newly-formed Applied Physics Laboratory (APL) at Johns Hopkins University, helping develop proximity fuses for weapons. By fall of that year, he had been commissioned as an officer in the US Navy and was sent to the South Pacific to field test the fuses. After World War II, Van Allen founded APL’s high-altitude research group, which used V-2 and Aerobee rockets to study cosmic rays and Earth’s upper atmosphere. In 1951 Van Allen returned to the University of Iowa, as professor and head of the physics department, where he remained until he retired in 1985. There, he collaborated with numerous institutions, including the Jet Propulsion Laboratory and NASA. As part of the US effort for the 1957–58 International Geophysical Year—which was first proposed in 1950 by several top scientists meeting in Van Allen’s living room —Van Allen directed the design and construction of the scientific instrumentation on Explorer 1, the US’s first successful space satellite, launched in 1958. The satellite’s Geiger counter provided data about Earth’s radiation belts , which were named for Van Allen. Van Allen would go on to participate in the development of numerous space probes built to study planetary and solar physics, including Mariner 2, Pioneer 10 and 11, Voyager, and Galileo. Among the many honors he received was the 1987 US National Medal of Science and the 1989 Crafoord Prize, awarded by the Royal Swedish Academy of Sciences. Van Allen died in 2006 at age 91. (Photo credit: AIP Emilio Segrè Visual Archives, Physics Today Collection)

Date in History: 7 September 1914