During World War II, two exiled German physicists wrote a paper about the possibility of constructing a “radioactive super-bomb” which was sent to appropriate agencies of the United Kingdom government. A committee was set up to explore building such a bomb and a research program was begun. Eventually, the U.K. entered into partnership with the United States and Canada in the Manhattan Project.
After World War II, the United States and the Soviet Union entered into a race to develop nuclear weapons. By the mid 50s, both nations had developed powerful hydrogen bombs. Constant ongoing research, development and testing resulted in the creation of tens of thousands of hydrogen bombs by both sides.
At the end of World War II, the victorious Allied powers divided the Korean peninsula at the 38th parallel. The southern portion of Korea was occupied by the United States which established a democratic government. The northern portion of Korea was occupied by Soviet troops and they established a communist government. As the Cold War took hold, hostility grew between the north and the south Korean governments.
In 1942, during the U.S. Manhattan Project to develop an atomic bomb, physicist Edward Teller promoted the idea of using an atomic blast to trigger a thermonuclear reaction that would result in a much bigger explosion. The Project team decided to focus on atomic bombs and not to explore his idea during the war.
Soviet scientists contributed much to the development of nuclear physics during the first decades of the Twentieth Century. When nuclear fission was discovered in the late 1930s, Soviet scientists understood that theoretically, enormous amounts of energy could be released from the fission of uranium. Work on fission research in the Soviet Union began in 1940.
In 1945, The United States was pouring resources into the Manhattan Project to create an atomic bomb. Part of the reason that the Manhattan Project was started in the first place was the knowledge that Germany was working on their own atomic bomb project. Werner Heisenberg was heading a team to develop a nuclear weapon for Germany but the German government failed to invest enough resources for the project to make much progress.
By 1945, the Japanese had been losing the war in the Pacific for two years. They had been driven off the Philippines and other islands that they had occupied. With the defeat of Germany in the European theater, the Russians deployed major portions of their armies to the Russian Far East. The Japanese merchant fleet which was critical for supplying war materials and fuel to the resource poor Japanese home islands had been destroyed.
After the dropping of the first atomic bomb on Hiroshima, Japan on August 6, 1945, the Japanese still would not surrender according to the Potsdam Declaration. Kokura had been selected as the primary target with Nagasaki as a backup target for the plutonium based Fat Man bomb. Nagasaki was a major Japanese port and was very important to the Japanese war effort due to the production of ammunition, ships, military equipment and other war supplies.
After the rejection of the demand for unconditional surrender by the Japanse government in July of 1945, the United States President, Harry S. Truman, decided to drop an atomic bomb on the Japanese city of Hiroshima. During World War II, Hiroshima on the Japanse island of Honshu was home to several military bases and industrial facilities that supplied the Japanese war effort.
After the Japanese rejected the U.S. demand for unconditional surrender in the spring on 1945, Harry Truman, the U.S. President authorized the use of atomic weapons in Japan. The Manhattan project had produced two nuclear weapons by that time, one based on uranium known as Little Boy and the other based on plutonium named Fat Man.
