The U.S. becomes the only country ever to use an atomic weapon in warfare, obliterating the Japanese city of Hiroshima and instantly killing 70,000 people. Thousands more will die later from radiation poisoning.
Several countries, including Germany, had worked on atomic weapons, but none matched the U.S. in the resources, energy, or scientific manpower devoted to making the bomb a reality. The discovery of nuclear fission in a Berlin laboratory in 1938 alarmed émigré scientists who had come to the United States to escape Nazism.
Fearing Germany might actually develop this ultimate weapon, they appealed to President Franklin D. Roosevelt to make nuclear research a high priority. Though skeptical at first, FDR was persuaded, and a civilian-military committee soon launched the Manhattan Project.
Development followed two paths, one strategy using uranium235, and the other plutonium. Both bombs were ultimately built: the uranium-based Little Boy was dropped on Hiroshima. Three days later, the plutonium-based Fat Man laid waste to the port city of Nagasaki with the ultimate loss of 140,000 lives. Japan surrendered, ending World War II.
The atomic scientists had favored demonstrating their weapon to the Japanese in an isolated area, but military and political planners argued the shock of total destruction would have more impact. The United States maintains that the decision to drop the bomb was made primarily to avoid the necessity of invading Japan, which would have resulted in enormous casualties on both sides. But many historians believe the real U.S. motive was to end the war before the Soviets could become involved, thus denying them a postwar stake in the Pacific.
Whatever the reasons, the bombs were dropped, and most Manhattan Project scientists later expressed remorse for what they had wrought.—TL