Hess V

Name: Hess, Victor Francis

ACHIEVEMENTS: Discovered cosmic rays

NICKNAME/ALIAS:

None

DATE AND PLACE OF BIRTH:

24 June 1883, Waldstein, Styria, Austria.

DATE AND PLACE OF DEATH AND AGE AT DEATH: 17 December 1964, Mount Vernon, NY. Aged 81

DISCIPLINE: Physicist

FIELD: Physics

LANGUAGE: German/English

EDUCATION:

Humanist School, Graz, Austria

University of Graz

MAJOR WORK:

LIFE AND TIMES:

In 1906 Hess began to study radiation at the University of Graz, researching atmospheric electricity and ionization. In 1908 he began teaching physics at Vienna Veterinary College.

In 1910 he took a research job at the newly established Radium Research Institute where he became an associate professor in 1911. In the same year he started to work on identifying the origin of the radiation responsible for atmospheric ionisation (and discovered cosmic radiation*).

During the nineteenth century it was thought that the earth's atmosphere was ionized in some way. In 1910 Theodor Wulf had conducted experiments on the Eiffel Tower, in which he found that the ionization of the atmosphere at 300 metres above a source of gamma rays was greater than the ionization at 300 metres horizontal distance from the rays.

This led him to admit the possibility of extraterrestrial sources of radiation. In the same year CTR Wilson*, a Scottish physicist, developed a cloud chamber which became an important research tool for extraterrestrial rays. Wulf suggested that the theory could be investigated by balloon experiments.

Hess designed an airtight ionization chamber and got the Austrian Aeroclub to help him make balloon flights. He made ten balloon flights, flying to a maximum height of 5,350 metres. He took scientific instruments with him and conducted day and night time experiments in order to investigate the role of the sun as a possible source of ionization.

He discovered that upwards of 150 metres above sea level, ionization increased significantly. Ionization was the same during night and day at all levels, so he knew the sun was not involved.

He concluded that there was a powerful source of radiation entering the earth's atmosphere and that the source of radiation was cosmic. Hess's findings were corroborated by experimental flights conducted by others, but his theory of cosmic radiation was not generally accepted at this time.

He set up a weather station at 2,141 metres on Hoch Obir mountain in Carinthia, but the experiments he hoped to conduct were ended by the outbreak of World War I in 1914. In 1921 Hess went to the United States, where he spent two years as director of research at the US Radium Corporation in Orange, New Jersey.

He then returned to Graz and was made a full professor in 1925. In that year, at Caltech Robert A Millikan coined the phrase "cosmic rays". Millikan had previously failed to validate Hess's theory of radiation but in 1926 he accepted it. Recognition by the general scientific community followed. In 1927 a Russian scientist using a Wilson cloud chamber found confirmatory evidence for cosmic ray ionization.

Hess found that he could get funds for new equipment and for new investigations into cosmic radiation. He conducted experiments in the Austrian Alps and on the island of Heligoland. (There was great interest within the international scientific community in the atmosphere and scientists such as Mauchly* in the United States were researching weather phenomena).

In 1931 Hess received international backing for his work, particularly from the Rockefeller Foundation. He left Graz and set up a cosmic-ray observatory at 2,300 metres on Hafelekar Peak at Innsbruck. In 1934 he had a thumb amputated after becoming contaminated with radioactive substances.

His work had contributed to the work being done on elementary particle physics and in 1936 he shared the Nobel Prize for physics with Carl Andersen, who had discovered the positive electron. Hess returned to Graz in 1937 but was dismissed a year later when the Nazis came to power. He was an obvious target for persecution, since he was a Roman Catholic with a Jewish wife, and had also been a scientific adviser to the Austrian government before Austro-German union.

The international community was eager for his services and he was offered a place by Manchester University, England, and by Fordham University in New York. He chose Fordham and became a naturalised American in 1944. He continued to investigate cosmic radiation, conducting experiments from the Empire State Building and on voyages to South America and in the Pacific.

He taught at Fordham until he retired in 1956, after which he became an emeritus. His researches included investigations into the dust pollution of the atmosphere, the gamma radiation of rocks, and the way in which workers in the field of radiation were affected by radioactive substances and fallout.

ASSESSMENT: Hess was responsible for the discovery of radiation sources in outer space.

EXTRA CONNECTIONS: None

ONELINER: Victor Hess, who discovered cosmic radiation

BIBLIOGRAPHY:

Pomerantz, Martin A, Cosmic Rays, Van Nostrand Reinhold Company, London, 1971

DSB

Encyclopedia Britannica

American National Biography

Victor Francis Hess - Wikipedia

PARENTS:

Father: Vinzenz Hess

Mother: Serafine Grossbauer-Waldstatt

SIBLINGS:

Unknown

SPOUSE:

1. Mary Bertha Warner
2. Elizabeth Hoenke

CHILDREN:

None