From 65438 to 0939, the atomic splitting experiment in the field of physics was successful in Germany. On the eve of World War II, some scientists who moved to the United States to escape the persecution of German fascists were worried that Germany would build an atomic bomb first, and recommended Einstein to write to US President Roosevelt, suggesting using the nuclear fission process to build a super bomb. President Roosevelt took the advice of Einstein and other scientists and ordered the establishment of a committee to study atomic weapons. The U.S. government entrusted this task to groves, and took the Manhattan Project as the secret code name of the project. The U.S. Army Corps of Engineers was solely responsible for developing the atomic bomb and hired Robert? Oppenheimer is the director of Los Alamos Laboratory, which makes atomic bombs. Oppenheimer put forward many far-sighted ideas in designing atomic bombs, calculating the critical mass required for their explosion and the method of initiating atomic bombs. The plan invested 2.5 billion US dollars and used more than 654.38 million scientific and technological personnel and workers, and stepped up research and development in absolute secrecy.
After Pearl Harbor, the United States accelerated the development of the atomic bomb. 1in June, 942, the nuclear program report submitted by Bush was approved. Under difficult conditions, after nearly three years of hard work, the world's first atomic bomb was finally developed successfully. 1945 At 5: 30 on July, the first atomic bomb "Big Boy" placed at the top of a 30-meter-high steel tower successfully exploded in the desert area of Alama Dole Air Force Base, New Mexico, USA. Its power is equivalent to 1500-2000 tons of TNT explosive. The experiment was successful and a powerful atomic bomb was born. Its appearance is an important scientific and technological achievement that affects the historical process of mankind in the 20th century. Since then, mankind has entered the nuclear age.