Manhattan Project was considered to be of the utmost importance In fact, many of the scientists and engineers were given only information that immediately affected their work, and they therefore were unaware of the larger implications of their research On December 2, 1942, a team led by Enrico Fermi, a Nobel Prize–winning physicist émigré from Italy, created the first controlled, self-sustaining nuclear chain reaction at the University of Chicago This proved that an atomic bomb many times more powerful than conventional weapons was possible The project focused on two main tasks The first was the design of the bomb Most of this work was done at the Los Alamos weapons lab in New Mexico under the direct supervision of Oppenheimer, who supervised the actual design and construction of the bomb The other task, the production of nuclear fuel, was undertaken at a site in Oak Ridge, Tennessee, that focused on isolating uranium isotopes Although the Manhattan Project had originally been conceived to combat a potential German nuclear weapon, work on the bomb would continue after Germany surrendered on May 8, 1945 U.S officials were determined to use the bomb against Japan in order to end the war at the earliest possible moment with the fewest casualties Secretary of War Henry Stimson told President Harry S Truman that the bomb could create problems for the United States because it could not maintain a monopoly on the technology Stimson requested that Truman convene a special committee to consider the implications of the new weapon Truman agreed, and the Interim Committee, made up of high-level advisers, held five meetings between May and June 1, 1945 The committee debated the most effective use of the bomb in order to expedite a Japanese surrender The committee determined that the weapon should be employed without prior warning, which would increase its psychological impact The committee suggested that the purpose of the bomb should be to impede the Japanese capacity to wage war and to shock the Japanese with the overwhelming destructive power of the bomb POLITICAL IMPLICATIONS The committee also debated the effects of the bomb on postwar international relations Although the Soviet Union remained aligned with the United States and Great Britain, tensions between the Allies continued to grow, especially over Soviet control of Eastern Europe The committee fully realized that the bomb could 237 increase the already tense relationship with the Soviet Union The committee discussed two ways of handling the issue The first would be to offer general information to the Soviets about the bomb in order to increase cooperation between the two allies The other approach would be to use the bomb to gain diplomatic advantages in U.S dealings with the Soviets, at least for the short term The committee was opposed to even providing general information on the bomb to the Soviets and determined that the United States should work to ensure that it stayed ahead of the Soviet Union in the research and production of nuclear weapons Truman accepted the committee’s findings For several months Truman had delayed a conference with Joseph Stalin and Winston Churchill until after a successful test of the plutonian bomb, planned for July, believing that a successful test would improve his bargaining position On July 16, 1945, the United States successfully exploded the first nuclear bomb in a test code-named Trinity at Alamogordo, New Mexico The force of the bomb equaled 18,600 tons of TNT, approximately 2,000 times more powerful than the British “Grand Slam,” the largest conventional bomb used in World War II ULTIMATUM At the end of the conference the Allies presented an ultimatum to Japan in what is known as the Potsdam Declaration The declaration called on Japan to unconditionally surrender to the Allies or face “prompt and utter destruction.” The United States elected not to specifically refer to the atomic bomb by name After Japan refused to surrender, Truman made the decision to drop atomic bombs on the Japanese home islands The Manhattan Project instituted Project Alberta, which involved the wartime delivery of the completed bomb Research groups were sent to Tinian, an island in the Pacific, which was the base from which the planes carrying the atomic weapons would ultimately depart On August at 8:15 a.m., the Enola Gay, piloted by Brigadier General Paul W Tibbets, released a 15kiloton uranium bomb nicknamed Little Boy 31,060 feet over the city of Hiroshima, Japan; 43 seconds later the bomb exploded 1,900 feet above the city Witnesses reported seeing a searing flash of light, hearing a deafening roar, and feeling a massive rush of air The 4.4 square miles surrounding the point of detonation were completely destroyed Estimates suggest that over