Little Boy and Fat Man are the code names for the two atomic bombs dropped by the United States on Hiroshima and Nagasaki in Japan at the end of World War II, which were the first nuclear bombs to be used in human history, causing hundreds of thousands of deaths and maiming and prompting Japan's surrender and the end of the war. The story of these two atomic bombs is a story about science, politics, strategy and morality, and it is a story that changes the world.
The birth of the little boy and the fat man was a secret project called the Manhattan Project launched by the United States during World War II in order to counter the threat of Germany and Japan, the purpose of which was to develop the atomic bomb, that is, to use the principle of nuclear fission to release huge energy and cause devastating damage. The Manhattan Project was approved by Roosevelt and later Truman, led by the US Army, led by physicist Oppenheimer, assisted by Britain and Canada, with the participation of thousands of scientists and engineers, costing about $2 billion and lasting about four years, and finally succeeded in creating three atomic bombs, namely Little Boy, Fat Man, and Atomic Bomb No. 3.
Little Boy is a uranium atomic bomb, that is, the nuclear fission of uranium-235 is used to produce energy, the principle of which is to hit two subcritical pieces of uranium-235 together through a gunpowder thruster to form supercritical uranium-235, triggering a chain reaction that releases a large number of neutrons and energy. The weight of the little boy is about 41 ton, about 3 meters in length and 0 in diameter7 meters, the power is about 130,000 tons of TNT equivalent, equivalent to 13,000 tons of explosives. The little boy was successful in his first nuclear test on July 16, 1945, at the Alamogordo Test Site in New Mexico.
Fat Man is a plutonium atomic bomb, that is, the nuclear fission of plutonium-239 is used to produce energy, the principle of which is to compress a hollow plutonium-239 spherical shell evenly through high ** drugs, so that it reaches a supercritical state, triggering a chain reaction, releasing a large number of neutrons and energy. The weight of a fat person is about 45 tons, length about 33 meters, with a diameter of about 15 meters, the power is about 210,000 tons of TNT equivalent, equivalent to 21,000 tons of explosives. The fat man did not conduct nuclear tests and was directly used in real combat.
The throwing of the little boy and the fat man was an extreme military action taken by the United States at the end of World War II in order to force Japan to surrender, and its background was that Japan refused to accept the Potsdam Declaration put forward by the United States and other allies, that is, the demand for unconditional surrender, and the United States decided to use the atomic bomb as a last resort to show Japan the determination and strength of the United States in order to avoid launching a landing war on the Japanese mainland and causing more American troops and Japanese. The targets of Little Boy and Fat Man were the Japanese cities of Hiroshima and Nagasaki, both of which were important military and industrial centers of Japan and potential landing sites for the United States, and had not been subjected to large-scale air raids, making them suitable targets for atomic bombs to show their effectiveness and impact.
On August 6, 1945, the B-29 bomber Enola Gay, piloted by Paul Tibbez, dropped at an altitude of about 580 meters above Hiroshima, and at 8:15 a.m. local time at about 600 meters in the air**, forming a fireball with a diameter of about 370 meters, reaching a temperature of millions of degrees Celsius, creating a mushroom cloud with a diameter of about 16 kilometers, releasing a strong shock wave, thermal radiation and nuclear radiation, destroying 80% of the city of Hiroshima Above the building, killed about 70,000 to 1260,000 people, about 70,000 disabled.
On August 9, 1945, the B-29 bomber Bokeka, piloted by Charles Savage, dropped at an altitude of about 500 meters over Nagasaki, and at 11:02 a.m. local time in the air of about 500 meters**, forming a fireball with a diameter of about 450 meters, the temperature reached millions of degrees Celsius, creating a mushroom cloud with a diameter of about 18 kilometers, releasing a strong shock wave, thermal radiation and nuclear radiation, destroying 35% of the city of Nagasaki The building killed about 60,000 to 80,000 people and maimed about 750,000 people. Knowledge explosion training camp