Manhattan Project
Origins and Early Research
The origins of the Manhattan Project can be traced back to fears among scientists in the United States that Nazi Germany was developing a weapon of unprecedented destructive power: an atomic bomb. This concern was triggered by the discovery of nuclear fission in late 1938 by German chemists Otto Hahn and Fritz Strassmann, and its theoretical explanation (and naming) by Lise Meitner and Otto Frisch soon after.
In August 1939, prominent physicists Leo Szilard and Eugene Wigner drafted the Einstein–Szilárd letter, which warned of the potential development of "extremely powerful bombs of a new type". The letter, signed by Albert Einstein, was sent to President Franklin D. Roosevelt and led to the establishment of the Advisory Committee on Uranium.
Project Sites and Organization
The Manhattan Project was a massive, nationwide endeavor that involved multiple research and production facilities. The project's three primary sites were the Los Alamos Laboratory in New Mexico, where the bomb was designed; the Hanford Engineer Works in Washington, where the plutonium was produced; and the Oak Ridge Reservation in Tennessee, where the uranium was enriched.
The project was under the direction of Major General Leslie R. Groves of the U.S. Army Corps of Engineers. Groves appointed J. Robert Oppenheimer, a theoretical physicist and professor at the University of California, Berkeley, as the scientific director of the project.
Scientific and Technological Challenges
The Manhattan Project faced numerous scientific and technological challenges. The project required the development of methods to extract and purify the necessary uranium-235 and plutonium, as well as the design and construction of the bombs themselves.
The project's scientists and engineers also had to develop the new field of nuclear physics, and create the mathematical models necessary to understand and predict the behavior of nuclear reactions. This required the construction of some of the world's first electronic computers, such as the IBM-designed and -built Harvard Mark I.
Impact and Legacy
The Manhattan Project had profound and lasting impacts. The project's successful development and use of atomic weapons marked the beginning of the Atomic Age, and ushered in a new era of military, political, and scientific developments.
The project also had significant effects on the cities where it was conducted, leading to rapid population growth and economic change. In addition, the project led to significant advancements in numerous scientific and technological fields, including nuclear physics, computer science, and materials science.