The development, test, and use of the first atomic bomb by the United States during World War II. Invention of The Atomic Bomb. Alamogordo & the Road to Nuclear Armament. On July 16, 1945, the United States detonated the first atomic bomb near Alamogordo, New Mexico, at the Alamogordo Test Range. In an area of the Jornada del Muerto Valley designated Trinity Site, the successful test was the culmination of years of scientific research.
Background for the Atomic Bomb
Throughout the 1930s, politicians and scientists, spurred by new discoveries in atomic theory, debated the theoretical plausibility of an atomic bomb. By 1939, American and British scientists began investigating the creation of such a weapon, particularly in light of Germany’s alleged ambitions to develop a bomb of their own. That same year, physicists Leo Szilárd and Albert Einstein wrote a letter to President Franklin D. Roosevelt urging the United States to build the weapon before Germany. Working with several expatriate European scientists, the U.S. government prioritized its development.
However, efforts did not move forward until 1942, when transferred under the authority of the U.S. Army as the Manhattan Project. The top military leader in charge, General Leslie R. Groves, oversaw all major aspects of the project at the three main facilities in Oak Ridge, Tennessee and Hanford, Washington, which manufactured the atomic materials, and Los Alamos, New Mexico, which served as the technical laboratory. Groves selected theoretical physicist J. Robert Oppenheimer for scientific director of the project, noting his scientific intellect, tactful manner, and previous work on several aspects of the bombs development prior to his appointment.
Developing the Atomic Bomb
Working out of the top-secret Los Alamos, Oppenheimer and his scientific teams focused on the design and material needed to create a nuclear chain reaction. In conjunction with such notables as Szilárd, who formulated the reaction concept in 1933, Enrico Fermi, and Niels Bohr, numerous scientists from around the country dedicated themselves to the project. They explored several concepts, with little practicality in their application. Confident a uranium-based bomb would work, two fission designs were proposed: one utilizing enriched uranium and the other its newly discovered derivative plutonium.
For the more complicated plutonium device, physicist Seth Neddermeyer, working off earlier proposals from others, posited the use of an “implosion technique”: a ball of plutonium at the weapon’s core imploded to a supercritical state by conventional high explosives, setting off the desired chain reaction. Oppenheimer, seeing merit in the idea, shifted focus to its development. By July 1945, a team that included chemist George Kistiakowsky, mathematician John von Neumann, and physicists Robert Christy and Edward Teller, readied a device, nicknamed “the Gadget.”
Testing the Atomic Bomb
Due to uncertainties in its capabilities, Groves and Oppenheimer agreed it necessary to test the Gadgets’ military usability. Under a veil of secrecy and morning thunderstorms, the plutonium-based bomb was detonated at Trinity on July 16 at 5:29 a.m. local time. The result was an explosion equivalent to 19 kilotons of TNT, creating a crater 10 feet deep and over 1,000 feet wide. By all accounts, it illuminated the surrounding landscape brighter than daylight for a few brief seconds. The mushroom cloud caused by the explosion extended nearly eight miles into the sky, while the resulting shockwave traveled as far as 100 miles. Noting the accomplishment, Oppenheimer stated simply, “It worked.” (He would later recall reflecting privately on a passage in the Hindu scripture, Bhagavad Gita: “Now, I am become Death, the destroyer of worlds.”)
Using the Atomic Bomb
President Harry S. Truman quickly authorized the use of the new weapon against Japan, whom the United States had been at war with for the past three and a half years. Truman’s top advisors, fearing major casualties in a proposed invasion of mainland Japan, concluded such action to be the best solution in ending hostilities between the two nations with minimal Allied losses. On August 6, a U.S. Army Air Force B-29 bomber, the Enola Gay, dropped the first of two bombs – the uranium-based “Little Boy” – on Hiroshima, Japan. Japan’s refusal to comply with surrender terms resulted in a second – similar in composition as the Trinity test bomb and codenamed “Fat Man” – being dropped on Nagasaki three days later. Due to the devastation caused, Japan formally surrendered to the Allies on August 15, 1945, ending World War II.
Reactions to the Atomic Bomb
Reactions to the bombings were immediate and mixed. While proponents celebrated the triumphal victory, critics questioned their necessity against an ostensibly defeated enemy. Some regarded them as unmitigated revenge for Pearl Harbor, while others saw them as a propaganda tool against the Russians. Whichever interpretation of the bombings one chooses, the Trinity test prior to them had irrevocably signaled an uncertain new era. Unbeknownst at the time, it became a means for ending one war and a symbol of a yet-undefined one – “the Cold War” – with the Soviet Union.