The Manhattan Project which was led by the US with the support of Canada and the UK was research, and development undertaking carried out during the Second World War to produce the first nuclear weapons. The project brought about a new revolution in arms technology thus rerouting military policy around the world. The scientists who were working on the Manhattan Project had one objective in mind which was to develop a super atomic weapon that would aid the US in securing victory during the Second World War over the Axis powers.

　　The Manhattan Project was conceived as a result of Albert Einstein’s knowledge of the atomic weapons being built by the Germans after which he sent a letter relaying this crucial information to Franklin Roosevelt the then President of the US. Soon after word got wind of Germany’s discovery, the development of the atom bomb was given the first and highest priority in regards to national security. As a result of the Manhattan Project, a secret atomic weapons development undertaking was launched in December 1941. Even though numerous individuals were called upon to help the US in developing an atomic bomb in a laboratory that was situated in Los Alamos, New Mexico, the following scientists had the most notable roles in the Manhattan Project. The Manhattan project cost about $2 billion (more than $70 billion in current rates) and employed more than 130,000 people. Research and production were carried out in more than 30 places all over the US, Canada, and the UK.

　　

6. J. Robert Oppenheimer

Statues of General Leslie R. Groves and J. Robert Oppenheimer from a Manhattan Project museum exhibit. Editorial credit: Jeffrey M. Frank / Shutterstock.com Born in 1904, Oppenheimer was an American theoretical physicist. He is widely regarded as the father of the atomic bomb. Oppenheimer possessed a profound intelligence which could be seen in some of his early academic achievements such as his invitation to lecture at the New York Mineralogical Club at the tender age of 12 years as well as graduating with a degree in chemistry from Harvard at age 15. Oppenheimer was chosen by the US army in 1942 to manage the laboratory working on the Manhattan Project. He was given a $2 million budget since the US army knew how vital it was to develop the atomic bomb before Germany. Because of Oppenheimer’s knowledge on the logistics involved in creating an atomic weapon as well as fast neutrons, he played a significant role in aiding the project to achieve its goal. Oppenheimer was the head of Los Alamos laboratory. Later after the war, Oppenheimer was appointed the chairman of the General Advisory Committee, a very influential organ of the United State Atomic Energy Commission. Oppenheimer used his position to lobby for control of nuclear weapons proliferation and the arms race with the Russians.

　　

5. Leo Szilard

Szilard, who worked closely with Einstein in drafting the letter sent to President Roosevelt, was a Hungarian physicist who earned physics degree at the University of Berlin alongside Einstein. Even though he did most of his early research and worked in Germany, Szilard had to flee Europe for fear of the Nazis. After the project was launched, Szilard became an integral part of the team and worked with a fellow scientist Enrico Fermi in developing the first self-sustaining nuclear chain reaction which was completed in 1942; it became a significant component in the production of a functional atomic bomb. Szilard conceived the idea of nuclear chain reaction in 1933, and in 1934 he patented the concept of nuclear reactor together with Enrico Fermi. He was working with the Metallurgical Laboratory of the Manhattan project and developed the design of the nuclear actor. He wrote the Szilard Petition supporting a demonstration of the atomic bomb; however, the interim committee opted to use them against cities without warning.

　　

4. Ernest O. Lawrence

Lawrence was an American nuclear physicist who took part in the Manhattan project; he attained his doctorate degree in 1928 from the University of California at Berkeley. He was the Manhattan Project’s Chief of Program where he played a significant role in research that involved the electromagnetic separation of atoms that were to be used in developing the atomic weapon. In 1939, Lawrence won the Nobel Prize in Physics for the invention of Cyclotron. He worked on separation of Uranium isotopes for the Manhattan Project and he also helped in founding the Lawrence Livermore National Laboratory and Lawrence Berkeley National Laboratory.

　　

3. Hans Bethe

Footage of the Trinity Test, the first testing of the detonation of a nuclear weapon for the Manhattan Project, on July 16, 1945. Born in 1906 in Strasbourg, Alsace-Lorraine, Bethe served as the Manhattan’s Project's Chief of Theoretical Division after departing Germany due to the rise of the Third Reich. Bethe was one of his generation’s most important theoretical physicists. Thus he was responsible for discovering some essential aspects that were crucial to the development of the atomic weapon. For instance, Bethe helped the project’s team create the formula needed for calculating an atomic bomb's explosive yield. Bethe contributed significantly to astrophysics, solid state physics, and quantum electrodynamics. In 1967, Bethe won the Nobel Prize in Physics for his numerous works on stellar nucleosynthesis theory. For much of his career he was a professor at Cornell University. Bethe played a major role in establishing the critical mass of the weapons and developed the theory of implosion method that was used in both the Trinity Test in New Mexico and the Fat Man bomb that was detonated in Nagasaki in 1945.

　　

2. Klaus Fuchs

Fuchs was a German theoretical physicist who doubled up as a spy for the Soviet Union, he was part of the project’s team, but on the side, he gave atomic secrets to the Soviet Union. Despite, Fuchs being a spy he played a significant role in contributing numerous significant theories that helped in the development of the atomic bomb. Eventually, Fuchs double life was discovered for which he was sentenced to 14 years in prison for trading crucial information.

　　

1. Glenn Seaborg

It was Seaborg who discovered Plutonium, a critical component used in the development of the atomic weapon. He was an America Chemist who earned his PhD at the University of California at Berkeley. Following his discovery, Seaborg was called to participate in the Manhattan Project where he was responsible for producing Plutonium-239 the crucial component used in the creation of the atomic bomb. Seaborg developed a functional way of separating, isolating, and concentrating plutonium.