The Shocking History of Oppenheimer's Bombs - The Manhattan Project

The True Story Behind the Bombs from Oppenheimer Just before dawn on July 16, 1945, generals and scientists watched nervously from trenches and bunkers for a flash in the New Mexico desert. When it came, the blast melted sand into glass, lit up the nearby mountains, and punched a hole through the clouds. Recordings capture the roar of the shockwave and towering mushroom cloud, but not the otherworldly purple light that faded into green and then white. The bomb’s architect, physicist J. Robert Oppenheimer, would recall feeling awed and somber. Witnesses, however, remember him as relieved … and triumphant. Welcome to WatchMojo, and today we’re looking at the true story behind the bombs from Oppenheimer. The idea for the atomic bomb came from rapid developments in atomic theory in the 1930s. The theory that matter consisted of discrete particles had been around for some time; but it was only proven in 1911, when French physicist Jean Perrin verified an earlier theory of Albert Einstein’s. Within decades, physicists had sketched out the atomic structure we’re familiar with today: a nucleus of protons and neutrons surrounded by a cloud of electrons. Then came a crucial breakthrough. In 1938, German chemists Otto Hahn and Fritz Strassmann bombarded uranium atoms with neutrons and split them in half - releasing considerable energy. They had stumbled on nuclear fission, a power that was about to change the world. Once they understood what they’d achieved, Hahn and Strassman predicted that the reaction’s release of additional neutrons could lead to a chain reaction. The double-edged sword of this realization, which could deliver us both a new source of energy and unprecedented destruction, was already apparent in May, 1939, when French physicists filed three patents - two for nuclear power production, and the third for an atomic bomb. It was a time of growing global tensions. In Germany, Nazi party leader Adolf Hitler had ridden a populist wave of national grievance to power, encouraging Germans to see themselves as the victims of World War I and its aftermath. He stoked resentment at the harsh terms of the Treaty of Versailles, which had required Germany to demilitarize and pay substantial reparations, and at Jews and socialists who, he said, had lost them the war. Nazi anger was a dam ready to burst and wash over Europe and potentially the world. In August 1939, as war loomed on the horizon, physicists Leo Szilard and Albert Einstein wrote a letter to U.S. President Franklin D. Roosevelt, warning that Germany might already be developing atomic weapons. The following month, Germany invaded Poland, igniting World War II; and that was the context in which Roosevelt finally read the letter in October. Alarmed, Roosevelt established an atomic committee. But it was thought at first that a vast amount of uranium would be needed, rendering such a bomb impractical. In March 1940, however, physicists Otto Frisch and Rudolf Peierls figured out that a small amount of a specific isotope, uranium-235, would be sufficient to start a nuclear chain-reaction. In December 1941, the Japanese bombing of Pearl Harbour drew the U.S. into the war. And the following year, the U.S. initiated the Manhattan Project - a secret program to build a bomb that could win the war. The project was headed by Major General Leslie Groves, with physicist J. Robert Oppenheimer directing the actual design of the bombs at Los Alamos Laboratory. The introspective intellectual had never led such a large project, but Groves sensed in him an “overweening ambition”, and that “he would let nothing interfere with the successful accomplishment of his task and thus his place in scientific history”. Spurring the project on was a terrible fear that Germany would beat the Allies to the bomb. Ironically, that same year, Germany had actually abandoned their nuclear program, lacking resources. But the Allies didn’t know that. Oppenheimer proved to be a capable leader. Under his direction, the project pursued two distinct designs, based on different methods of initiating a nuclear chain reaction. The simple, gun-type design would shoot one piece of fissile material into another. An early version, Thin Man, which used plutonium, was abandoned, as risking predetonation; its successor, Little Boy, used uranium-235 instead. Oppenheimer used plutonium in the second design - a more complex implosion-type that involved detonating explosives around a plutonium core. This produced the bomb, named the ‘Gadget’, used in the Trinity Test in July, 1945, and a bomb called Fat Man. By the time of the Trinity Test, Germany had already surrendered. But Japan fought on. On July 26, the Allies called for Japan’s unconditional surrender, warning of “prompt and utter destruction". Japan refused, and President Harry S. Truman authorized the use of the bombs. It was 08:15 on August 6 when the U.S. bomber Enola Gay released Little Boy over the Japanese city Hiroshima. Parents and children were having breakfast at home, or on their way to work and school. The bomb detonated 1,900 feet over the city. The blast wave tore through buildings and people and created a firestorm in its wake. At least 70,000 were killed. Some survived with horrible burns, barely recognizable. Three days later, when Japan still refused to surrender unconditionally, the U.S. dropped the even more powerful Fat Man on Nagasaki. The total death toll of the bombs is estimated to be between 129,000–226,000 people - mostly civilians. As Japan admitted defeat, Americans celebrated in the streets. The war was over. In the months afterwards, journalists would discover scenes of horror at Hiroshima and Nagasaki, where people were vomiting blood and dying from a mysterious affliction - radiation sickness. The military sought to suppress reports from the ground, and the U.S. government to frame the bombings of civilian targets as a necessary evil. A guilt-wracked Oppenheimer would confront Truman, saying he felt he had blood on his hands, and be angrily thrown out. He would go on to oppose the development of the even more powerful hydrogen bomb. Accused of disloyalty, in part due to his associations with communists, he was stripped of his security clearance - ending his role in government policy. Today, there remain an estimated 13,080 nuclear warheads in the world. 90% of them are owned by the U.S. and Russia. Thanks to disarmament and non-proliferation treaties, that’s considerably less than the 70,000 warheads that existed at the peak of the Cold War; but still enough to cause massive global destruction. Other nations with nukes include the U.K., France, China, and unofficially, India, Pakistan, North Korea, and Israel. Since 1947, the Bulletin of the Atomic Scientists’ Doomsday Clock has tracked how close we seem to be to human-made global catastrophe. On January 24, 2023, the clock was moved forward to 90 seconds to midnight - marking “a time of unprecedented danger”. The images of the destruction that the bombs wrought continue to haunt us - reminding us of the horrific power we now hold in our hands.