Category:Manhattan Project Scientists

Albert Einstein signed the 1939 letter that is credited with starting American nuclear weapons research, and then never worked on the program it produced, having been kept away from it over his pacifist and left-leaning politics. The category collects biographical entries on people connected to the Manhattan Project, the wartime American program that built the first nuclear weapons. Its membership divides cleanly into the theorists who did the physics at Los Alamos, Chicago and Oak Ridge, and the two civilian officials who authorized the program and answered for it, which is why a president and a secretary of war sit in a category otherwise made of physicists.

The project ran across several sites with different jobs. The Metallurgical Laboratory in Chicago built the first self-sustaining chain reaction; Oak Ridge in Tennessee handled uranium enrichment and later became a national laboratory; Hanford in Washington produced plutonium; and the Los Alamos Laboratory in New Mexico designed the weapon itself. Members of this category appear at each of them, and several moved between sites as the work shifted.

Two features of the membership follow from the project's timing. Physicists were recruited very young, in some cases before finishing an undergraduate degree, because the work needed people faster than the academic pipeline produced them. And an unusual proportion of the participants went on to Nobel Prizes in Physics for work done after the war, using instruments and reactors the project had left behind.

J. Robert Oppenheimer directed the Los Alamos Laboratory and oversaw the design and construction of the first nuclear weapons. Enrico Fermi built the first artificial nuclear reactor, Chicago Pile-1, achieving the first self-sustaining chain reaction on December 2, 1942, and continued at Oak Ridge, Hanford and Los Alamos. Richard Feynman was recruited shortly after completing his doctoral work in 1942, was assigned to the theoretical division under Hans Bethe, who made him a group leader despite his junior status, and worked on fission calculations and uranium enrichment design. John Archibald Wheeler had already developed the theory of nuclear fission with Niels Bohr, worked at the Metallurgical Laboratory in Chicago designing reactors, and moved on to Hanford.

The youngest participants are the most striking. Roy Glauber was eighteen when his undergraduate studies at Harvard were interrupted by recruitment to Los Alamos, where he worked on critical mass and chain reaction calculations; he received the 2005 Nobel Prize in Physics for the quantum theory of optical coherence. Frederick Reines joined the theoretical division at Los Alamos in 1944 on completing his doctorate, in a group led by Feynman, later directed nuclear weapons test operations in the Pacific, and received the 1995 Nobel Prize in Physics for the first detection of the neutrino, nearly four decades after the experiment.

Joseph Rotblat is the exception in the group and belongs in any account of it. He came to Los Alamos in 1944 when the British Tube Alloys program was merged into the American project, and left the same year on grounds of conscience, having concluded that Nazi Germany had abandoned its own nuclear program. He was the only scientist to leave for that reason before the bomb was completed, and he received the 1995 Nobel Peace Prize for the disarmament work that followed.

Franklin D. Roosevelt authorized the program. Henry L. Stimson ran it as Secretary of War and bore direct responsibility for it, in a career that also produced the Stimson Doctrine and the insistence on judicial prosecution of Nazi war criminals at Nuremberg.

A separate group in this category was shaped by the project without working on it, and readers should not confuse the two. Clifford Shull joined Oak Ridge National Laboratory in 1946, after the war, and turned the X-10 Graphite Reactor built for plutonium production toward peacetime research, founding the field of neutron diffraction and sharing the 1994 Nobel Prize in Physics for it. Charles Ergen was born in Oak Ridge in 1953, in a town built for the project and populated by the scientists and engineers it drew from across the country, and went on to found EchoStar and DISH Network. Christopher Nolan directed the 2023 film about Oppenheimer. Steven Chu invoked the project as the scale of effort climate change would require, in the argument that carried him toward the Department of Energy.

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