Building the Bomb

In 1932, British scientist James Chadwick discovered an atomic particle, the neutron, which could penetrate the nucleus of an atom and cause it to separate. The divided atom would release more neutrons, causing other atoms to split. As the chain reaction progressed and built up, an enormous amount of energy would be released.

During the first days of World War II, leading physicists such as Albert Einstein suspected that Germany was already at work to create a massive weapon of annihilation, better known as the atomic or A-bomb. They pooled together, and in 1939, Einstein wrote the president to tell him of their suspicions. Fortunately, the president heeded the warning.

Albert Einstein, best known for his theory of relativity, collaborated with several physicists in writing to President Roosevelt to warn him of possible German attempts to make the atomic bomb. This lent urgency to American efforts to build the A-bomb, but Einstein played no role in the work and had no knowledge of what would be called the Manhattan Project.

In 1942, many prominent scientists began developing the A-bomb in a small Tennessee community (as well as in research sites such as Los Alamos, New Mexico). The undertaking was termed “the Manhattan Project” because some of the work took place at Columbia University. Physicists Enrico Fermi and J. Robert Oppenheimer worked on the Manhattan Project, as did chemist Harold Urey. U.S. Army engineer General Leslie Groves headed the project that at one time involved approximately 600,000 people.

Oak Ridge, Tennessee (near Knoxville), originally called Clinton Engineer Works, was founded in 1942 by the U.S. government to produce the uranium for the Manhattan Project. By the end of the war, the town's population had grown to more than 80,000.

The Bomb Put to Use

After V-E Day, the war in the Pacific theater still raged on. American bombing raids on Japan's industrial centers met with limited success. Radar, still in its infancy, proved too unreliable to use in designating targets. Even B-29 bombing raids aimed at residential and civilian targets didn't convince the Japanese to surrender, and the raids were proving to be costly as well.

With the Manhattan Project, U.S. scientists proved they could use the explosive power of nuclear fission rather than TNT to wreak mass destruction. Oppenheimer and his team tested the A-bomb near Alamogordo, New Mexico, on July 16, 1945. No one knew whether it would work until a tremendous blast rushed across the desert. Oppenheimer's team informed President Truman that it had indeed worked.

Although the bomb had originally been created for possible use against Hitler's Third Reich, Truman now faced a crucial decision — whether to use the A-bomb against the Japanese in order to end the war. Truman didn't want to risk the lives of American servicemen in a potential invasion of Japan, and it's said he had little to no hesitation in using this powerful new weapon. At Potsdam (outside Berlin in July 1945), Churchill agreed that Truman should use the A-bomb.

At 8:15 a.m. on August 6, 1945, an American B-29 bomber named the Enola Gay ferried the bomb to Hiroshima, the Japanese city chosen for the drop. There, it exploded about 2,000 feet above the ground, producing a fireball hotter than the surface of the sun and leveling several square miles. Atomic radiation and searing heat vaporized everything in its range.

Japan Brought to Its Knees

Surprisingly, Japan didn't ask for terms of surrender following the attack on Hiroshima. So on August 9, another B-29 bomber dropped an A-bomb on the city of Nagasaki, causing almost as much destruction as the first bombing. Meanwhile, the Soviet Union had declared war on Japan on August 8, destroying its army in China and taking over most of occupied Manchuria. The Red Army was continuing its move into Korea as Japan finally surrendered to the Allies on August 15, 1945. This wasn't an unconditional surrender, as the Allies agreed that the Japanese could keep their emperor. The formal signing took place on September 2 in Tokyo Bay aboard the battleship Missouri with an American delegation headed by General MacArthur, who then became the military governor of Allied-occupied Japan.

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