Atomic bombings of Hiroshima and Nagasaki


August 19, 2022

The atomic bombings of Hiroshima and Nagasaki were two nuclear attacks, carried out at the end of the Second World War and carried out by the United States against Japan, which marked the end of the conflict. On the morning of August 6, 1945, at 8:15 am, the US Air Force dropped the Little Boy atomic bomb on the city of Hiroshima. This bombing was followed, three days later, by another atomic release; this time it was Fat Man's turn on Nagasaki. The number of direct victims is estimated between 150,000 and 220,000 people, almost exclusively civilians: due to the severity of the damage caused - direct and indirect - and the ethical implications related to them, this was the first and only use in war of such weapons, although their development registered a dangerous surge in the following years.

Historical context

Scientific research on the atom and military applications

After Ernest Rutherford's successful atom shattering experiment in 1919, scientific research in nuclear physics had progressively developed thanks to the contribution of world-renowned scientists such as Niels Bohr, Werner Heisenberg, James Chadwick and Enrico Fermi. They presented the new theories of quantum physics, they identified the neutron but above all they discovered that the bombardment of the atom with neutrons produced isotopes of new elements. Based on theoretical calculations based on Albert Einstein's famous formula, the shattering of the atom seemed to be able to release an enormous amount of energy. In 1938 Otto Hahn and Fritz Strassmann defined the phenomenon of nuclear fission while two other researchers, Lise Meitner and Otto Frisch, discovered that uranium was an unstable element particularly suitable for crushing with the consequent release of energy. However, it was mainly thanks to Leó Szilárd that he came to the conception of the so-called chain reaction, that is the possibility of an element shattering under the bombardment of neutrons with the emission of a higher number of particles in turn capable of attacking other atomic nuclei thus prolonging the fission process. Szilard understood the frightening practical implications of these discoveries in the military field and was the first, in 1938, to warn against the danger of an uncontrolled disclosure of scientific news that could militarily benefit aggressive powers such as Nazi Germany.

Strategic situation in the Pacific

The role of the bombings in the surrender of the Japanese Empire, as well as the effects and justifications, have been the subject of countless debates: in the United States the opinion prevails that they served to shorten the conflict by several months while saving the lives of soldiers. (both Allied and Japanese) and civilians, destined to perish in ground and air operations in the planned invasion of Japan. In Japan, public opinion tends to argue that the bombings were real war crimes perpetrated to accelerate the surrender process of the Japanese military government. Others argue that they could not be justified only by a victory on the Japanese front (now close to surrender), but that they were a demonstration of power towards what was looming as the new enemy, namely the Soviet Union. Finally, some add to the motivations that of testing the power of the bomb (costing billions of dollars) on a city: this would explain the use of different types of bombs during the two bombings. However, the awareness of the seriousness of the event, which has never been repeated, is universally shared. The month before the bombing, the conquest of Okinawa, which caused the death of 150,000 Japanese civilians and soldiers and the loss of approximately 70,000 soldiers.