The Manhattan Project was one of the most important scientific undertakings in history. How long did the project take?
The Manhattan Project took three years, between 1942 and 1945, culminating in the use of the first atomic bombs. Preliminary work had started years four years earlier in 1938, following the discovery of nuclear fission and Einstein’s warning that Germany might seek to use it as a weapon.
For more on the Manhattan Project and how it changed the world, read on.
In 1938, German scientists Otto Hahn and Fritz Strassman discovered nuclear fission during the course of their experiments. Hahn, along with his colleague Lise Meitner and Otto Frisch, Meitner’s nephew, conducted further experiments, proving that it was possible to split the uranium nucleus.
The discovery had world-changing implications. The newly discovered atomic energy might be used for good or, more concerningly as the world moved nearer to war, for terrible destructive purposes.
Albert Einstein and Leo Szilard wrote a letter to President Roosevelt and warned him of the possibility that Nazi Germany might attempt to use the new technology to create an atomic bomb.
Roosevelt responded by forming the Uranium Committee, consisting of some of the top military and scientific minds. It had the task of researching the possibility of a nuclear chain reaction.
In 1941, the British MAUD Committee released a report that expressed their belief that the creation of an atomic bomb was possible. The group proposed working alongside the Uranium Committee in an attempt to stay ahead of German scientists.
The Uranium Committee was replaced by the S-1 Committee, part of the Office of Scientific Research and Development. The S-1 Committee found itself short of funds and approached the United States Army for financial support.
The Manhattan Project was formed on August 13, 1942, though it was not the group’s original name and was used simply because it was based in Manhattan. It was also called the Manhattan Engineer District.
Research continued at universities around the United States, with scientists making independent discoveries. At the University of Chicago, on December 2, 1942, scientists activated Chicago Pile-1, the first self-sustaining nuclear reactor.
Soon after, President Roosevelt granted the project $500 million in funding and it relocated to Washington, DC. There were several other locations around the United States, with the weapons research laboratory and testing site based in Los Alamos, New Mexico.
The work was top secret, particularly so in Los Alamos, which was guarded by the US Army. Weapons research was directed by J. Robert Oppenheimer, with thousands of workers living in the town. There are believed to have been more than 600,000 people involved in the project in some form.
The Manhattan Project developed two different types of atomic bombs: uranium-based and plutonium-based. Even before the first atomic explosion, the 509th Composite Group of the Army Air Forces was training for an eventual atomic bombing.
On July 16, 1945, “The Gadget” was detonated at the Trinity site in New Mexico. The explosion that resulted from the plutonium-based bomb was a stark declaration of the birth of the atomic age.
The United States government had been considering the military application of the atomic bomb since the project began. President Harry S. Truman now faced the dilemma of whether or not to authorize its use.
With American forces within bombing range of the Japanese mainland and facing the prospect of a long and extremely costly campaign, the decision was made to use the atomic bomb.
On August 6, 1945, a uranium-based bomb called “Little Boy” was dropped on Hiroshima, delivered by the “Enola Gay” airplane. More than 200,000 people are believed to have died as a result of the bombing.
Three days later, a plutonium-based bomb called “Fat Man” was dropped on Nagasaki, delivered by a plane called “Bockscar”. Approximately 80,000 people are believed to have died by the end of 1945.
Japan offered its surrender on August 14, 1945. The moral implications of using the atomic bomb have long been debated. It undoubtedly brought World War II to a close, but some have questioned whether or not a public demonstration of the weapon by the United States might have achieved the same results.
The Manhattan Project was hugely significant. It led to a nuclear arms race between the western powers and the Soviet Union during the Cold War. However, it also led to beneficial civilian applications as an efficient power source.