Victor Franz Hess

Hess, Victor Franz (Francis) (1883–1964), Austrian American physicist who shared the 1936 Nobel Prize for physics (with Carl David Anderson) for his discovery of cosmic rays.

Born at Schloss Waldstein, Styria, Austria, on June 24, 1883, Hess graduated from the Humanistisches Gymnasium in Graz in 1901 and received his Ph.D. degree from the University of Graz in 1906. After two years of advanced work at the latter, he became a privatdocent in physics at the Vienna Veterinary College. In 1910 he was appointed an assistant at the newly founded Institute for Radium Research at the University of Vienna and a year later was named associate professor.

Hess was appointed associate professor at the University of Graz in 1920, but he soon left that position to serve two years (1921–1923) as director of the United States Radium Corporation’s research laboratory in Orange, N.Y. During the same period he was also a consulting physicist for the U.S. Department of Interior’s Bureau of Mines. Returning to the University of Graz in 1923, Hess became a full professor in 1925 and dean of the faculty in 1929. He was professor of experimental physics and head of the institute for radiation research at the University of Innsbruck from 1931 to 1937, when he once again returned to Graz to direct its physics institute. Dismissed from his position in 1938, following the Nazi occupation of Austria, because he had served as a science adviser to the independent Austrian government, and warned that he and his Jewish wife would soon be sent to a concentration camp, Hess immigrated to the United States and taught physics at Fordham University in New York City from 1938 to 1956, when he retired. He became a U.S. citizen in 1944 and died in Mount Vernon, N.Y., on Dec. 17, 1964.

Physicists long knew that the leaves of a charged gold-leaf electrometer would slowly collapse if the instrument were allowed to stand in air. In the 1890s the English physicist Joseph John Thomson showed that air becomes a conductor when ionized by X rays or other radiation of high frequency. Physicists generally concluded that the air was ionized by radiation from minerals in the ground, the ionization then permitting the electrometer to discharge. 

After the Jesuit amateur physicist Theodore Wulf’s determination in 1910 that the air at the top of the Eiffel Tower (984 feet, or 300 meters, above the ground) was more ionized than that at the bottom raised doubts about the ground-origin hypothesis, Hess made ten balloon ascents (1911–1913) to determine how high the background radiation extended. He found to his surprise that, above an altitude of about 1 mile (1.6 km), the ionization was many times greater than at the earth’s surface. He concluded that this radiation, initially named for him, originated in space. In 1925 the American physicist Robert A. Milliken dubbed it cosmic radiation, or cosmic rays.

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