Robert Oppenheimer (1904-1967)

 

Professor Julius Robert Oppenheimer was an American theoretical physicist and professor of physics.

As the wartime head of the Los Alamos Laboratory, Oppenheimer is among those who are called the 'father of the atomic bomb' for their role in the Manhattan Project, the World War II project that developed the first nuclear weapons used in the atomic bombings of Hiroshima and Nagasaki.

He was born in New York City on April 22, 1904. His family were non-observant Ashkenazi Jews and he had a younger brother, Frank, who also became a physicist. Oppenheimer attended Alcuin Preparatory School, and then the Ethical Culture Society School from 1911.  He was a promising student and
he quickly became interested in chemistry. He accepted a place Harvard College but had to defer a year, starting when he was 18, because he suffered an attack of colitis during a family summer holiday in Europe. In 1924 Oppenheimer was informed that he had been accepted into Christ's College. He only spent two terms at Cambridge, before taking up a place at the University of Göttingen to study under Max Born. Göttingen was one of the world's leading centers for theoretical physics at the time.

He obtained his Doctor of Philosophy degree in March 1927 at the age of 23. Oppenheimer published more than a dozen papers at Göttingen, including many important contributions to the new field of quantum mechanics. He and Born published a famous paper on the Born–Oppenheimer approximation, which separates nuclear motion from electronic motion in the mathematical treatment of molecules, allowing nuclear motion to be neglected to simplify calculations. It remains his most cited work.

As well as the Born–Oppenheimer approximation, Oppenheimer's achievements in physics include for molecular wavefunctions, work on the theory of electrons and positrons, the Oppenheimer–Phillips process in nuclear fusion, and the first prediction of quantum tunneling. With his students he also made important contributions to the modern theory of neutron stars and black holes, as well as to quantum mechanics, quantum field theory, and the interactions of cosmic rays.

Oppenheimer was awarded a United States National Research Council fellowship to the California Institute of Technology (Caltech) in September 1927. He was also wanted at Harvard, so a compromise was reached whereby he split his fellowship for the 1927–28 academic year between Harvard in 1927 and Caltech in 1928. In the autumn of 1928, Oppenheimer visited Paul Ehrenfest's institute at the University of Leiden, the Netherlands, where he impressed by giving lectures in Dutch, despite having little experience with the language. From Leiden he continued on to the Swiss Federal Institute of Technology (ETH) in Zurich to work with Wolfgang Pauli on quantum mechanics and the continuous spectrum.  On returning to the United States, Oppenheimer accepted an associate professorship from the University of California, Berkeley, where Raymond T. Birge wanted him there so much that he expressed a willingness to share him with Caltech. At Berkeley he prospered as an advisor and collaborator to a generation of physicists who admired him for his intellectual virtuosity and broad interests. In 1936 Berkeley promoted him to full professor, in return for curtailing his teaching at Caltech, so a compromise was reached whereby Berkeley released him for six weeks each year, enough to teach one term at Caltech.

On October 9, 1941, shortly before the United States entered World War II, President Franklin D. Roosevelt approved a program to develop an atomic bomb. In May 1942, National Defence Research Committee Chairman James B. Conant, who had been one of Oppenheimer's lecturers at Harvard, invited Oppenheimer to take over work on fast neutron calculations. He was given the title 'Coordinator of Rapid Rupture'. In June 1942, the US Army established the Manhattan Engineer District to handle its part in the atom bomb project. In September, Groves was appointed director of what became known as the Manhattan Project and he in turn selected Oppenheimer to head the project's secret weapons laboratory.

Oppenheimer and Groves decided that for security and cohesion they needed a centralised, secret research laboratory in a remote location. They settled on a flat mesa near Santa Fe, New Mexico, which was the site of a private boys' school called the Los Alamos Ranch School. The Los Alamos Laboratory was built on the site of the school, taking over some of its buildings, while many others were erected in haste. There Oppenheimer assembled a group of the top physicists of the time, which he referred to as the "luminaries". Los Alamos grew from a few hundred people in 1943 to over 6,000 by 1945.

The joint work of the scientists at Los Alamos resulted in the first artificial nuclear explosion near Alamogordo on July 16, 1945, on a site that Oppenheimer codenamed "Trinity".

The first atomic bomb was detonated on July 16, 1945. Oppenheimer remarked later that it brought to mind words from the Bhagavad Gita: Now I am become Death, the destroyer of worlds.

At an assembly at Los Alamos on August 6 (the evening of the atomic bombing of Hiroshima), Oppenheimer noted his regret the weapon had not been available in time to use against Nazi Germany. However, he and many of the project staff were upset about the bombing of Nagasaki, as they did not feel the second bomb was necessary from a military point of view. He travelled to Washington on August 17 to hand-deliver a letter to Secretary of War Henry L. Stimson expressing his revulsion and his wish to see nuclear weapons banned. For his services as director of Los Alamos, Oppenheimer was awarded the Medal for Merit from President Harry S Truman in 1946.

After the bombings of Hiroshima and Nagasaki, the Manhattan Project became public knowledge and Oppenheimer became a national spokesman for science. He became a household name and his face appeared on the covers of Life and Time magazines. Nuclear physics became a powerful force as all governments of the world began to realise the strategic and political power that came with nuclear weapons.

In November 1945, Oppenheimer left Los Alamos to return to Caltech, but he soon found that his heart was no longer in teaching. In 1947, he accepted an offer to take up the directorship of the Institute for Advanced Study in Princeton, New Jersey. Shortly after, the Atomic Energy Commission (AEC) came into being in 1947 as a civilian agency in control of nuclear research and weapons issues and Oppenheimer was appointed as the Chairman of its General Advisory Committee (GAC). From this position he advised on a number of nuclear-related issues, including project funding, laboratory construction and even international policy—though the GAC's advice was not always heeded. As Chairman of the GAC, Oppenheimer lobbied vigorously for international arms control and funding for basic science, and attempted to influence policy away from a heated arms race

In his speeches and public writings, Oppenheimer continually stressed the difficulty of managing the power of knowledge in a world in which the freedom of science to exchange ideas was more and more hobbled by political concerns. Oppenheimer delivered the Reith Lectures on the BBC in 1953, which were subsequently published as Science and the Common Understanding. In 1955 Oppenheimer published The Open Mind, a collection of eight lectures that he had given since 1946 on the subject of nuclear weapons and popular culture. Oppenheimer rejected the idea of nuclear gunboat diplomacy. In 1957 the philosophy and psychology departments at Harvard invited Oppenheimer to deliver the William James Lectures which were six lectures, entitled The Hope of Order. Oppenheimer delivered the Whidden Lectures at McMaster University in 1962, and these were published in 1964 as The Flying Trapeze: Three Crises for Physicists.

Oppenheimer continued to lecture, write and work on physics. He toured Europe and Japan, giving talks about the history of science, the role of science in society, and the nature of the universe. In September 1957, France made him an Officer of the Legion of Honor, and on May 3, 1962, he was elected a Foreign Member of the Royal Society in Britain. At the urging of many of Oppenheimer's political friends who had ascended to power, President John F. Kennedy awarded Oppenheimer the Enrico Fermi Award in 1963.

In 1954, Oppenheimer spent several months of the year living on the island of Saint John in the U.S. Virgin Islands. In 1957, he purchased a 2-acre (0.81 ha) tract of land on Gibney Beach, where he built a spartan home. He spent a considerable amount of time sailing with his daughter Toni and wife Kitty. Oppenheimer was diagnosed with throat cancer in late 1965 and, after inconclusive surgery, underwent unsuccessful radiation treatment and chemotherapy late in 1966. He fell into a coma on February 15, 1967, and died at his home in Princeton, New Jersey, on February 18, aged 62. His ashes were scattered into the water on Gibney Beach.

Oppenheimer was nominated for the Nobel Prize for physics three times, in 1945, 1951 and 1967, but never won.

 
 

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