Werner Kolhörster

Werner Heinrich Gustav Kolhörster (December 28, 1887 – August 5, 1946) was a German physicist and a pioneer of research into cosmic rays.

Kolhörster was born in Schwiebus (Świebodzin), Province of Brandenburg. While attending the University of Halle, he studied physics.cite book
author=Mehra, J.; Rechenberg, H.
year=1987
title=The Historical Development of Quantum Theory
edition=1st edition
publisher=Springer-Verlag
location=New York
id=ISBN 0387962840 ]

Repeating the cosmic ray experiments of Victor Hess, in 1913-14 Kolhörster ascended by balloon to an altitude of 9 km, where he confirmed Hess' result that the ionization rate from cosmic rays was greater at that altitude than at sea level. This was evidence that the source for these ionizing rays came from above the Earth's atmosphere. [cite web
author = Putje, A.; Fourier, J.
date=June 2006
url = http://democrite.ccsd.cnrs.fr/docs/00/10/66/75/PDF/Report.pdf
format=PDF
title =Propagation of cosmic rays in the Earth's atmosphere
publisher =HAL-IN2P3
pages=165
accessdate = 2007-05-18 ]

Kolhörster continued his physics studies at the "Physikalisch-Technische Reichsanstalt" in Berlin, beginning in 1914. During World War I he made measurements of atmospheric electricity in Turkey. Following the war he became a teacher. He joined the "Physikalisch-Technische Reichsanstalt" in 1922.

In 1928–29, Walter Bothe and Kolhörster used the Geiger-Muller detector to demonstrate that cosmic rays were actually charged particles. The ability of these particles to penetrate the Earth's atmosphere meant that they must be highly energetic. [cite web
author=Staff
date =February 5, 2000
url =http://www.sciencenews.org/articles/20000205/timeline.asp
title =From the February 1, 1930, issue
publisher =Science News
accessdate = 2007-05-18 ]

In 1930, Kolhörster started the first institute for the study of cosmic rays in Potsdam, with financial assistance from the Prussian Academy. He became director of the "Institut für Hohenstrahlungsforschung" in Berlin-Dahlem in 1935, where he was appointed an ordinary professor.

Kolhörster was killed in a car crash in Munich. Kolhörster crater on the Moon was named in his memory.

References