Manhattan Project

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Manhattan Project

Manhattan Project, the wartime effort to design and build the first nuclear weapons (atomic bombs). With the discovery of fission in 1939, it became clear to scientists that certain radioactive materials could be used to make a bomb of unprecented power. U.S. President Franklin Delano Roosevelt responded by creating the Uranium Committee to investigate this possibility. Progress was slow until Aug., 1942, when the project was placed under U.S. Army control and reorganized. The Manhattan Engineer District (MED) was the official name of the project. The MED's commanding officer, Gen. Leslie R. Groves, was given almost unlimited powers to call upon the military, industrial, and scientific resources of the nation.

A $2-billion effort was required to obtain sufficient amounts of the two necessary isotopes, uranium-235 and plutonium-239. At Oak Ridge, Tenn., the desired uranium-235 was separated from the much more abundant uranium-238 by a laborious process called gaseous diffusion. At the Hanford installation (Wash.), huge nuclear reactors were built to transmute nonfissionable uranium-238 into plutonium-239. This method was based on the principle of the self-sustaining nuclear reaction (nuclear pile) that had first been achieved under the leadership of Enrico Fermi at the metallurgical laboratory of the Univ. of Chicago. At the radiation laboratory of the Univ. of California at Berkeley costly efforts were made to separate the two uranium isotopes using cyclotrons, but only about a gram of pure uranium-235 was obtained. The actual design and building of the plutonium and uranium bombs took place at Los Alamos, N.Mex., under the leadership of J. Robert Oppenheimer. Gathered at this desert laboratory was an extraordinary group of American and European-refugee scientists.

The only nuclear test explosion, code-named Trinity, was of a plutonium device; it took place on July 16, 1945, near Alamogordo, N.Mex. The first uranium bomb (“Little Boy”) was delivered untested to the army and was dropped on Hiroshima on Aug. 6, 1945, killing at least 70,000 inhabitants. On Aug. 9, 1945, a plutonium bomb virtually identical to the Trinity device was dropped on Nagasaki, killing at least 35,000 inhabitants.


See L. R. Groves, Now It Can Be Told (1962); L. Lamont, Day of Trinity (1965); H. Feis, The Atomic Bomb and the End of World War II (rev. ed. 1966); R. Rhodes, The Making of the Atomic Bomb (1987); R. S. Norris, Racing for the Bomb (2002).

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Manhattan Project

[man′hat·ən ‚prä‚jekt]
A United States project lasting from August 1942 to August 1946, which developed the atomic energy program, with special reference to the atomic bomb.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
References in periodicals archive ?
Although the University of Chicago already was renowned in physics and chemistry before World War II, scientists who worked on the Manhattan Project helped those departments attain new research prominence following the war.
One reason that the British were willing to merge their own nuclear weapons work into that of the Manhattan Project was that the sheer burden of continuing the conventional war against Hitler, amid the risks of German bomber and missile attacks, made it unlikely that Britain could produce atomic bombs before World War II had ended.
What if America and Britain had accepted at face value the signals that Werner Heisenberg may have tried to transmit via Bohr, that there was not any real German nuclear weapons program that the Manhattan Project had to preempt?
At its peak, the Manhattan Project was as big as the auto industry, employing 130,000 people at remote sites across the country.
The Manhattan project, which produced the atomic bomb, and the Apollo program, which landed American men on the moon, have been cited as examples of the success such R&D investments can yield.
troops in Iraq became targets of roadside bombs, generals urged the Pentagon to launch a Manhattan Project to counter the deadly attacks.
Lamar Alexander (R-Tenn.), on May 9, proposed "launching a 5-year New Manhattan Project to put America firmly on the path to clean energy independence within a generation."
President, I have just one question: Where in Tennessee do you want me to hide it?" That place in Tennessee turned out to be Oak Ridge, one of three secret cities that became the principal sites for the Manhattan Project.
Conveying the romance and power of the Manhattan Project and its magnificent & terrible achievement, it is a touching reminder of a New Athens with more scientific and technical brainpwer than has been assembled before or since.
We think that they are quite advanced, much = beyond the level of the Manhattan Project.

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