Hess, Victor Francis (1883–1964)

Austrian physicist who emigrated to the USA shortly after he shared the Nobel Prize for Physics in 1936 for the discovery of cosmic radiation.

Hess was born in Waldstein and educated at Graz. From 1906 to 1920 he worked in Vienna, studying radioactivity and atmospheric ionization. He was professor at Graz 1920–31 and at Innsbruck 1931–38, founding a cosmic-ray observatory on the nearby Hafelekar mountain. After the Nazi annexation of Austria, he emigrated to the USA, becoming professor at Fordham University, New York.

Hess made ten balloon ascents in 1911–12 to collect data about atmospheric ionization. Ascending to altitudes of more than 5,000 m/16,000 ft, he established that the intensity of ionization decreased to a minimum at about 1,000 m/3,000 ft, then increased steadily. By making ascents at night – and one during a nearly total solar eclipse – he proved that the ionization was not caused by the Sun. He concluded that radiation enters the atmosphere from outer space.