Fritz Zwicky

From Free net encyclopedia

Fritz Zwicky (February 14 1898 – February 8 1974) was an American-based Swiss astronomer.

Life and work

Fritz Zwicky was born in Varna, Bulgaria, although his parents were from Switzerland. He received an advanced education at the Swiss Federal Institute of Technology, located in Zürich, Switzerland. In 1925 he emigrated to the United States.

In 1925 he came to the California Institute of Technology (Caltech), in the United States. He worked at Caltech for the rest of his career but remained a Swiss citizen. He is famous for referring to colleagues with whom he disagreed as "spherical bastards" (because, he claimed, they were bastards any way one looked at them). He was the first to use the virial theorem to deduce the existence of dark matter. However, until recently, much of his work on dark matter was rejected (he was coined "crazy Fritz" by some colleagues.) Recently dark matter has become more acceptable as an explanation for galactic rotation curves. He proposed the use of gravitational lenses. With Walter Baade, he came up with the idea that supernovae could create neutron stars and produce cosmic rays. He also pioneered and promoted the use of Schmidt telescopes. In his later career, he compiled a Catalogue of Galaxies and of Clusters of Galaxies (CGCG). He won the Gold Medal of the Royal Astronomical Society in 1972.

The asteroid 1803 Zwicky, the Zwicky lunar crater, and the galaxy I Zwicky 18 were all named in his honour.

Fritz Zwicky created the 'tired light' theory in 1929 as an alternative to Georges LeMaitre's and Edwin Hubble's interpretation of the cosmic red shift. LeMaitre and Hubble believed that the cosmic red shift is caused by a doppler effect of universal expansion. Fritz Zwicky believed that the cosmic red shift is caused by photons gradually losing energy over distance, possibly due to resisting the gravitational fields between the source and the detector. The idea is that the photons transfer energy to massive bodies through the gravitational interaction, resulting in a reduction of the photon frequency. Such frequency shifts do exist, but they are extremely small, will sometimes result in an increase in frequency, and are associated with a change in direction of the photon. Zwicky's proposal was never accepted by more than a small minority of physicists.

Zwicky also developed a generalised form of morphological analysis, which is a method for systematically structuring and investigating the total set of relationships contained in multi-dimensional, usually non-quantifiable, problem complexes (Ritchey, 2002). He wrote a book on the subject (Zwicky, 1969), and claimed that he made many of his discoveries using this method.

[edit]