J. Robert Oppenheimer (1904 – 1967)
J. (Julius) Robert Oppenheimer was born in New York City on April 22, 1904. His parents, Julius S. Oppenheimer, a wealthy German textile merchant, and Ella Friedman, an artist, were of Jewish descent but did not observe the religious traditions. He studied at the Ethical Culture Society School, whose physics laboratory has since been named for him, and entered Harvard in 1922, intending to become a chemist, but soon switching to physics. He graduated summa cum laude in 1925 and went to England to conduct research at Cambridge University’s Cavendish Laboratory, working under J.J. Thomson.
In 1926, Oppenheimer went to the University of Göttingen to study under Max Born, obtaining his Ph.D. at the age of 22. There, he published many important contributions to the then newly developed quantum theory, most notably a famous paper on the so-called Born-Oppenheimer approximation, which separates nuclear motion from electronic motion in the mathematical treatment of molecules. In 1927, he returned to Harvard to study mathematical physics and as a National Research Council Fellow, and in early 1928, he studied at the California Institute of Technology. He accepted an assistant professorship in physics at the University of California, Berkeley, and maintained a joint appointment with California Institute of Technology. In the ensuing 13 years, he “commuted” between the two universities, and many of his associates and students commuted with him.
Oppenheimer became credited with being a founding father of the American school of theoretical physics. He did important research in astrophysics, nuclear physics, spectroscopy and quantum field theory. He made important contributions to the theory of cosmic ray showers, and did work that eventually led toward descriptions of quantum tunneling. In the 1930s, he was the first to write papers suggesting the existence of what we today call black holes.
In November 1940, Oppenheimer married Katherine Peuning Harrison, a radical Berkeley student, and by May 1941 they had their first child, Peter. When World War II began, Oppenheimer eagerly became involved in the efforts to develop an atomic bomb, which were already taking up much of the time and facilities of Lawrence’s Radiation Laboratory at Berkeley. He was invited to take over work on neutron calculations, and in June 1942 General Leslie Groves appointed Oppenheimer as the scientific director of the Manhattan Project.
Under Oppenheimer’s guidance, the laboratories at Los Alamos were constructed. There, he brought the best minds in physics to work on the problem of creating an atomic bomb. In the end, he was managing more than 3,000 people, as well as tackling theoretical and mechanical problems that arose. He is often referred to as the “father” of the atomic bomb. (In 1944, the Oppenheimers’ second child, Katherine (called Toni), was born at Los Alamos.) The joint work of the scientists at Los Alamos resulted in the first nuclear explosion at Alamagordo on July 16, 1945, which Oppenheimer named “Trinity.”
After the war, Oppenheimer was appointed Chairman of the General Advisory Committee to the Atomic Energy Commission (AEC), serving from 1947 to 1952. It was in this role that he voiced strong opposition to the development of the hydrogen bomb. In 1953, at the height of U.S. anticommunist feeling, Oppenheimer was accused of having communist sympathies, and his security clearance was taken away. The scientific community, with few exceptions, was deeply shocked by the decision of the AEC. In 1963, President Lyndon B. Johnson attempted to redress these injustices by honoring Oppenheimer with the Atomic Energy Commission’s prestigious Enrico Fermi Award.
From 1947 to 1966, Oppenheimer also served as Director of Princeton’s Institute for Advanced Study. There, he stimulated discussion and research on quantum and relativistic physics in the School of Natural Sciences. Oppenheimer retired from the Institute in 1966 and died of throat cancer on February 18, 1967.
The People Profiles | 21 July 2023
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