Victor Hess

Victor Franz Hess (German: [ˈvɪktɔʁ ˈfʁants ˈhɛs]; 24 June 1883 – 17 December 1964) was an Austrian–American experimental physicist who shared the 1936 Nobel Prize in Physics with Carl David Anderson for his discovery of cosmic rays.^[2]

Victor Hess
Hess in 1936
Born	Victor Franz Hess (1883-06-24)24 June 1883 Deutschfeistritz, Duchy of Styria, Austria-Hungary
Died	17 December 1964(1964-12-17) (aged 81) Mount Vernon, New York, US
Citizenship	Austria United States (from 1944)
Alma mater	University of Graz University of Vienna (Dr. phil.)
Known for	Discovering cosmic rays
Spouses	Marie Breisky ​ ​ (m. 1920; died 1955)​ Elizabeth Hoenke ​ (m. 1955)​
Awards	Lieben Prize (1919) Nobel Prize in Physics (1936) Austrian Decoration for Science and Art (1959)
Scientific career
Fields	Atmospheric physics
Institutions	Institute for Radium Research (1910–20) University of Graz (1920–21, 1923–31, 1937–38) United States Radium Corporation (1921–23) University of Innsbruck (1931–37) Fordham University (1938–58)
Academic advisors	Franz S. Exner[1] Leopold Pfaundler[1]

Education

Victor Franz Hess was born on 24 June 1883 at Waldstein Castle in Deutschfeistritz, Styria, the son of Vinzenz Hess and Serafine Edle von Grossbauer-Waldstätt. His father was a royal forester in Prince Louis of Oettingen-Wallerstein's service. He attended Graz Gymnasium from 1893 to 1901.^[3][4] He then studied at the University of Graz from 1901 to 1905 and received his Ph.D. in 1906 from the University of Vienna,^[5] where he stayed to do postdoctoral research until 1910.

Career

In 1910, Hess became an assistant to Stefan Meyer at the Institute for Radium Research. In 1920, he was appointed Extraordinary Professor of Experimental Physics at the University of Graz. In 1921, he took a leave of absence and traveled to the United States, where he became Director of the Research Laboratory at the United States Radium Corporation in New Jersey, and Consulting Physicist for the US Bureau of Mines in Washington, DC. In 1923, he returned to Graz, where he was appointed Ordinary Professor of Experimental Physics in 1925. In 1931, he was appointed Director of the Institute of Radiology at the University of Innsbruck.^[3] In 1937, he once again returned to Graz to become Director of the Institute of Physics.

In 1938, following Nazi Germany's annexation of Austria, Hess was dismissed by the University of Graz and moved to the United States. The same year, he was appointed Professor of Physics at Fordham University in New York City, a position he held until his retirement in 1958. He became a naturalized US citizen in 1944.^[6][7]

Discovery of cosmic rays

Hess (center) on the return from his balloon flight, 1912

For many years, scientists had been puzzled by the levels of ionizing radiation measured in the atmosphere. The assumption at the time was that the radiation would decrease as the distance from the earth, the then assumed source of the radiation, increased. The electroscopes previously used gave an approximate measurement of the radiation but indicated that at greater altitude in the atmosphere the level of radiation might actually be higher than that on the ground. He approached this mystery first by greatly increasing the precision of the measuring equipment, and then by personally taking the equipment aloft in a balloon. He systematically measured the radiation at altitudes up to 5.3 kilometres (3.3 mi) during 1911–1912. The daring flights were made both by day and during the night, at significant risk to himself.^[4]

The result of Hess' meticulous work was published in the Proceedings of the Austrian Academy of Sciences, and showed the level of radiation decreased up to an altitude of about 1 kilometre (0.6 mi), but above that the level increased considerably, with the radiation detected at 5 kilometres (3.1 mi), being about twice that at sea level.^[8] His conclusion was that there was radiation penetrating the atmosphere from outer space, and his discovery was confirmed by Robert Millikan, who gave the radiation the name cosmic rays. His discovery opened the door to many new discoveries in particle and nuclear physics.^[4] In particular, both the positron and the muon were first discovered in cosmic rays by Carl David Anderson. In 1936, Hess and Anderson shared the Nobel Prize in Physics for their discoveries of cosmic rays and the positron, respectively.

Personal life and death

In 1920, Hess married Marie Bertha Warner Breisky, who died of cancer in 1955.^[2] The same year, he married Elizabeth M. Hoenke, who nursed Marie at the end of her life.^[6]

Hess was a practicing Roman Catholic.^[9] In 1946, he wrote on the topic of the relationship between science and religion in his article "My Faith", in which he explained why he believed in God.^[10][11]

Hess died of Parkinson's disease on 17 December 1964 in Mount Vernon, New York, at the age of 81.^[2]

Awards and honors

• Lieben Prize (1919)
• Nobel Prize in Physics (1936)
• Austrian Decoration for Science and Art (1959)^[12]

Hess crater on the Moon is named after him.

Books

• Hess, Victor F. (1928). The Electrical Conductivity of the Atmosphere and its Causes.