What Was The Manhattan Project? | History Hit

What Was The Manhattan Project?

Amy Irvine

19 Jan 2023
The Trinity explosion, 16 ms after detonation. The viewed hemisphere's highest point in this image is about 200 metres (660 ft) high
Image Credit: Public Domain, via Wikimedia Commons; History Hit

The Manhattan Project was the codename for the US government’s secret research and development program during World War Two that produced the world’s first nuclear weapons. The project was led by the US, but also had participation from the UK and Canada.

Led by physicist J. Robert Oppenheimer, the Manhattan Project was conducted by the US Army Corps of Engineers, with the support of the University of Chicago, Columbia University, and the Massachusetts Institute of Technology. Its goal was to develop a nuclear weapon before Nazi Germany did.

The project was successful and on 16 July 1945, the first nuclear weapon was tested in Alamogordo, New Mexico. Less than a month later, on 6 and 9 August 1945, atomic bombs were dropped on the Japanese cities of Hiroshima and Nagasaki respectively, leading to Japan’s surrender and the end of World War Two.

What led to the Manhattan Project, how did they achieve their goal and what was its long term impact?

The potential for atomic weapons

The Manhattan Project had been sparked by fears that Nazi Germany was also working on developing a nuclear weapon, having been the first country to discover nuclear fission.

After the invasion of Poland by Nazi Germany in 1939, Albert Einstein and other prominent scientists warned the US government of the danger threatening all of humanity if the Nazis should be the first to make a nuclear bomb, writing a letter to President Roosevelt. They urged him to fund research into the development of a nuclear weapon, and subsequently Roosevelt established the Office of Scientific Research and Development to oversee the project.

Albert Einstein (left) and Oppenheimer (right)

Image Credit: Public Domain, via Wikimedia Commons

Challenges faced by the Manhattan Project

The main research and development of the actual bombs was done at the Los Alamos Laboratory in New Mexico, under the direction of nuclear physicist J. Robert Oppenheimer. His laboratory brought together some of the brightest scientists and engineers from around the world and worked tirelessly to design and build a functional nuclear weapon, using the newly discovered process of nuclear fission to release a tremendous amount of energy.

Specifically, the laboratory had to develop methods of reducing the fissionable products to pure metal, then fabricate this metal to required shapes. Methods of rapidly bringing together amounts of fissionable material to achieve a supercritical mass (and consequently a nuclear explosion) had to be developed, as well as the construction of a weapon that could be dropped from a plane and fused to detonate at the necessary moment whilst in the air above its target.

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The project had several challenges to overcome – notably the need to produce large amounts of highly enriched uranium and plutonium, the materials needed for the bomb. To this end, several large-scale facilities were built, including the Oak Ridge facility in Tennessee and the Hanford facility in Washington state. They employed tens of thousands of workers, many of whom were unaware of the true purpose of the work they were doing.

Another challenge was the need for secrecy. The project was given the highest level of security clearance, with only a select few individuals aware of its true purpose – the project was so secretive that even President Roosevelt was not fully informed of its details.

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Immediate impact

Despite these challenges, the project was a success. On 16 July 1945, the first nuclear weapon was detonated in a test at Alamogordo airbase, 120 miles south of Albuquerque, New Mexico.

It had a blast equivalent to 20,000 tons of TNT and created a fireball that reached temperatures of several million degrees. The resulting mushroom cloud extended to 12,200 metres, and the surrounding desert surface fused to glass for a 730 metre radius.

The success of the Manhattan Project had a profound impact on world events when America used atomic bombs on the Japanese cities of Hiroshima and Nagasaki in August 1945 which lead to the rapid surrender of Japan and the end of the war in the Pacific, ending World War Two. The bombings killed over 200,000 people, most of whom were civilians.

Wider impact

The Manhattan Project also ushered in the nuclear age, with countries around the world racing to develop their own nuclear weapons. This in turn had a profound impact on international relations, leading to a state of constant tension and the ongoing threat of nuclear war, most notably highlighted during the Cuban Missile Crisis in October 1962.

Mushroom cloud after Fat Man exploded over Nagasaki on 9 August 1945

Image Credit: Public Domain, via Wikimedia Commons; History Hit

The Manhattan Project also had a major impact on science and technology. The project brought together some of the brightest minds in science and engineering, and their work laid the foundation for many technological advancements such as the development of the computer, the internet and the development of nuclear power and its role in energy production.

The project also led to the creation of the US Atomic Energy Commission, later known as the US Nuclear Regulatory Commission.

Whilst the Manhattan Project was successful and ultimately served to end World War Two as well as leading to scientific and technological advancements, its success also serves as a reminder of the destructive power of nuclear weapons and the importance of international cooperation in preventing their use.

Amy Irvine