University of Texas
Rainer K. Sachs
July 12, 1932– April 16, 2024



Rainer K. "Ray" Sachs


Rainer Kurt "Ray" Sachs (born June 13, 1932) is a German-American computational radiation biologist and astronomer. He and Arthur M. Wolfe (UT 1967) were the authors of the Sachs–Wolfe effect, which concerns a property of the Cosmic microwave background radiation. On large angular scales, this effect is the most important of various physical processes by which the primordial density fluctuations should have left their imprint on the cosmic microwave background radiation in the form of small variations in the temperature of this radiation in different directions on the sky. The effect is essentially gravitational in origin. Photons traveling from the last scattering surface to an observer encounter variations in the metric which correspond to variations in the gravitational potential in Newtonian gravity. Astrophysical Journal, 1967, 147, 73. It is thought that the ‘ripples' found by the COBE satellite were due to the Sachs–Wolfe effect. Sachs and Ronald Kantowski (UT 1966) were responsible for the Kantowski–Sachs dust solutions to the Einstein field equation. These are a widely used family of inhomogeneous cosmological models.

Sachs was born in Frankfurt am Main in 1932, to George and Liselotte Lehman Sachs. George, born in Moscow, Russia, was a German Jewish metallurgist. In 1937, the family left Germany to flee from Nazi persecution. George emigrated earlier, March 20, 1936, on the Deutschland and was living at 23 Briarcliff Avenue, Mt. Lakes, N. J. His passage was paid by Durener Metallwerke. The remainder of the family left Hamburg on April 22, arriving New York, April 30, 1937, on the S. S. New York from Hamburg. Liselotte's widowed mother, Margaret Lehman, accompanied them. They had $84. Rainer siblings include Peter Lorenz (born Goslar, Germany) and Marie Margarate Klara (born Berlin). In the 1940 U. S. Census, George is a professional consultant with University Metal in Cleveland Heights, Ohio. Ray's mother's original name was Lisclott Emilie Jenny Lehmann and she was born February 11, 1904 in Soran, Germany. She and George married October 14, 1924, in Goslar, Germany.

Ray received his B.Sc. in mathematics from Massachusetts Institute of Technology in 1953 and his PhD in theoretical physics from Syracuse University in 1958 under the supervision of Peter G. Bergmann. His dissertation was entitled, "The Structure of Particles in Linearized Gravitational Theory." After postdocs abroad, he was appointed Assistant Professor at Stevens Institute of Technology in Hoboken, NJ. In 1963, he became an Associate Professor of physics at the University of Texas, and was promoted to Professor in 1965. In 1969, he moved to the University of California at Berkeley, where is was appointed Professor. He was a Guggenheim Fellow at Cambridge University during 1972-1973.

On August 20, 1955, Ray married Sally M. Katorski in Syracuse, New York. Sally graduated from East High School in Buffalo, New York where she was valedictorian. She attended Syracuse University where she starred on their College Quiz Bowl team. She and Rainer were divorced in 1977. Sally Sachs is active with the Berkeley Architectural Heritage Association.

From 1969 to 1993, Sachs was Professor of Mathematics and Physics at the University of California, Berkeley (UCB), and from 1993 he has been Professor Emeritus at UCB. In 1994, he was appointed Research Professor of Mathematics UCB, and since 2005 he has been an Adjunct Professor at Tufts University School of Medicine. Until 1985, he worked on general relativistic cosmology and astrophysics. With Hung-Hsi Wu he co-wrote the books General Relativity for Mathematicians and General Relativity and Cosmology which was published in 1977. His contributions include joint work on the Sachs-Wolfe effect and the Ehlers-Geren-Sachs theorem, both of which deal with the Cosmic Microwave Background Radiation. From 1985, he has worked in mathematical and computational biology, especially radiation biology. His work in radiobiology has included research on radiation and cancer. His work was supported by DOE, NSF, NIH and NASA.

Some of research topics are: 1) large-scale DNA structure and damage by ionizing radiation; 2) estimating risk of radiation carcinogenesis. Techniques involve mathematics, modeling and programming. Data are obtained by colleagues at various labs worldwide or are in the literature.

Ray died April 16, 2024 at the age of 91.



Rainer Kurt "Ray" Sachs Photo and Document Album

Ray Sachs
Sally Sachs
Ray Sachs
Ray Sachs
Ray Sachs, 197
Ray Sachs
Nancy & Robert Judson Clark and Sally Sachs at right, Berkeley Architectural Heritage Association
Rainer K. Sachs, 1949 University School for Boys Yearbook

Rainer K. Sachs, John A. Wheeler and Dieter Brill

Fourth Texas Symposium on Relativistic Astrophysics, Dallas, Texas, December 16–20, 1968

Relativity Conference in Banff, Alberta, Ray Sachs, fourth from left end.



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