On October 11, 1939, US President Franklin Roosevelt received a letter from Albert Einstein and other scientists about the possibility of producing an atomic bomb.
As early as August 2, 1939, Einstein wrote his first letter to US President Roosevelt, revealing to him the possibility of the Germans creating an atomic bomb and urging America to take further action to stimulate development. A few years later, Einstein realized his role in this historical moment and deeply regretted it.
The hostilities became the reason for the acceleration of all military developments, and finally the atomic bomb was tested in practice for the first time, hitting Hiroshima and Nagasaki.
Here is the text of Einstein's letter:
Sir:
Part of the recent work of E. Fermi and L. Szilard, which has been brought to my attention by means of a manuscript, leads me to suppose that the element uranium may become a new and important source of energy in the very near future. Certain aspects of the situation that have arisen suggest vigilance and, if necessary, prompt action on the part of the Administration. I therefore feel it my duty to draw your attention to the following facts and recommendations.
During the last four months it has been suggested, through the work of Joliot in France, and of Fermi and Szilard in America, that it may be possible to establish a nuclear chain reaction with a large mass of uranium, by which enormous power and large quantities of new elements, such as radium, will be produced. It is now almost certain that this will be accomplished in the near future.
This new phenomenon will also lead to the invention of bombs, and we may assume, though with less certainty, that extremely powerful bombs of this kind can be made in this way. A single bomb of this kind, carried by ship and exploded in a harbor, could convincingly destroy the entire harbor with some adjacent territory. In any case, such bombs may prove too heavy to be transported by air.
The United States possesses only poor uranium ores in limited quantities. There is good ore in Canada and the former Czechoslovakia, but the most important source of uranium is in the Belgian Congo.
In view of this situation, you may consider it desirable to maintain constant contact between the Administration and the group of physicists working on chain reactions in America. One possible option for you would be to assign the task to a person you trust and who could perhaps assist as an informal factor. His task might be to:
a) reach out to government departments, keep them informed of further developments, and to advance recommendations for government action, paying special attention to the problem of the protection of uranium ore supplied to the United States.
b) to intensify the experimental work which is at present being carried on within the budgets of university laboratories, by raising funds, if necessary, through his contacts with private individuals who are willing to contribute to the cause, and perhaps also by obtaining assistance from industrial laboratories which have the necessary equipment.
I understand that Germany has actually stopped purchasing uranium from the Czechoslovak mines which she has seized. The fact that Germany had to take such early action may be understood as implying that the son of German Deputy Foreign Minister von Weizsäcker was attached to the Kaiser-Wilhelm-Institut in Berlin, where some of the American work on uranium was being resumed.
Sincerely yours,
Albert Einstein
The atomic bomb is the fruit of European scientific thought from the end of the 19th and the first half of the 20th centuries and of the fears and ambitions of the great powers during World War II. The first successful development was the Manhattan Project, implemented by the USA during the war years, but the main scientists who initiated it and brought it to a successful conclusion were European citizens.
This multinationality and the awareness of the terrible destructive capabilities of the atomic and later created hydrogen bombs.
The first 3 bombs were detonated in 1945 as the final phase of the “Manhattan“ project. On July 16, near Alamogordo, New Mexico, the world's first nuclear test, called “Trinity“ (an implosive plutonium bomb with a capacity of 20 kt was detonated). On August 6, the “Little One“ bomb (an artillery uranium bomb with a capacity of 13 kt) was detonated over Hiroshima, Japan. On August 9, the “Fat Girl“ bomb was detonated over Nagasaki, Japan. (analogous to “Trinity“).
Russia detonated its first atomic bomb on August 29, 1949 at the Semipalatinsk test site in Kazakhstan.