The start of the cold war
In 1938, Hahn and Strassmann sent a manuscript to a journal reporting that they had discovered the element barium after bombarding unranium with neutrons. This was the first publication about a nuclear fission experiment. Nuclear fission is a nuclear reaction in which the nucleus of an atom splits into smaller parts (lighter nuclei). This fission process can produce free neutrons, and releases a very large amount of energy.
The Hungarian physicist Leó Szilárd, who was residing in the United States at the time, realized that the neutron-driven fission of heavy atoms could be used to create a "nuclear chain reaction". It was thus a possibility that the fission of uranium could yield vast amounts of energy for civilian or military purposes, especially the atomic bomb.
The Hungarian physicist Leó Szilárd, who was residing in the United States at the time, realized that the neutron-driven fission of heavy atoms could be used to create a "nuclear chain reaction". It was thus a possibility that the fission of uranium could yield vast amounts of energy for civilian or military purposes, especially the atomic bomb.
Support of Einstein
Szilard urged other researchers to refrain from publishing on the possibility of a chain reaction in order to avoid that the Nazi government would become aware of this possibility.
In August 1939, Szilárd and his fellow Hungarian physicists Teller and Wigner thought that the Germans might make use of the fission chain reaction to create nuclear bombs. So they persuaded the most famous German scientist at that time Albert Einstein to lend his name to a letter directed to President Roosevelt. This letter (see below) suggested the possibility of an uranium bomb deliverable by ship, which could destroy "an entire harbor and much of the surrounding countryside.”
Szilard urged other researchers to refrain from publishing on the possibility of a chain reaction in order to avoid that the Nazi government would become aware of this possibility.
In August 1939, Szilárd and his fellow Hungarian physicists Teller and Wigner thought that the Germans might make use of the fission chain reaction to create nuclear bombs. So they persuaded the most famous German scientist at that time Albert Einstein to lend his name to a letter directed to President Roosevelt. This letter (see below) suggested the possibility of an uranium bomb deliverable by ship, which could destroy "an entire harbor and much of the surrounding countryside.”
The President received the letter on October 11, 1939 — shortly after World War II began in Europe, but two years before the U.S. entry into the war -- Roosevelt ordered that a scientific committee be authorized for overseeing uranium work and allocated a small sum of money for pilot research.
The Manhattan Project
The so called Manhattan Project began modestly in 1939, but after the US entered into the war the project grew: more than 130,000 people were involved and the total cost were about $27 billion in dollars of 2017.
This extreme expensive project was started based on guesses about the development of a new weapon by the enemy. There was no proof needed for that because the scientists knew that it was possible because they themselves could develop this weapon. We will see later that there is reason to believe that in the so called “arms races“ this is not an unusual procedure.
From 1942 to 1946, the project was under the direction of Major General Leslie Groves of the US Army Corps of Engineers. Los Alamos, in New Mexico, was the scientific research center for design and development of the bomb. The overall scientific direction of the project was managed by the physicist Robert Oppenheimer.
In July 1945, the first atomic explosive device, called "Trinity", was tested in the desert of New Mexico. On the way to the test site some fear arose under the scientists whether it was possible that the stratosphere would be blown up by the explosion with catastrophic consequences. It has been told that the mathematician Von Neumann quickly has made some calculations on the back side of an envelope and came to the conclusion that this consequence was not possible. The test was a success so much so that the researchers were shocked by the consequences of the explosion although the stratosphere was not affected.
In the meantime the production of more bombs went on. The bombs were not necessary anymore for Germany because Germany already was declared defeated a month before.
The Manhattan Project
The so called Manhattan Project began modestly in 1939, but after the US entered into the war the project grew: more than 130,000 people were involved and the total cost were about $27 billion in dollars of 2017.
This extreme expensive project was started based on guesses about the development of a new weapon by the enemy. There was no proof needed for that because the scientists knew that it was possible because they themselves could develop this weapon. We will see later that there is reason to believe that in the so called “arms races“ this is not an unusual procedure.
From 1942 to 1946, the project was under the direction of Major General Leslie Groves of the US Army Corps of Engineers. Los Alamos, in New Mexico, was the scientific research center for design and development of the bomb. The overall scientific direction of the project was managed by the physicist Robert Oppenheimer.
In July 1945, the first atomic explosive device, called "Trinity", was tested in the desert of New Mexico. On the way to the test site some fear arose under the scientists whether it was possible that the stratosphere would be blown up by the explosion with catastrophic consequences. It has been told that the mathematician Von Neumann quickly has made some calculations on the back side of an envelope and came to the conclusion that this consequence was not possible. The test was a success so much so that the researchers were shocked by the consequences of the explosion although the stratosphere was not affected.
In the meantime the production of more bombs went on. The bombs were not necessary anymore for Germany because Germany already was declared defeated a month before.
Use of the bombs on Japan
However in the Far East the war against Japan was still going on: island after island would have to be conquered by the US army which would cost a lot of human lives. Therefore the military command of the US and the President considered whether this weapon could be used to shorten the war against Japan and save a lot of lives of American soldiers. In the scientific community in Los Alamos and elsewhere a lot of discussion took place and even motions were made against this plan, given the fact that they were afraid that this would lead to a nuclear arms race with the Soviet Union.
However in the Far East the war against Japan was still going on: island after island would have to be conquered by the US army which would cost a lot of human lives. Therefore the military command of the US and the President considered whether this weapon could be used to shorten the war against Japan and save a lot of lives of American soldiers. In the scientific community in Los Alamos and elsewhere a lot of discussion took place and even motions were made against this plan, given the fact that they were afraid that this would lead to a nuclear arms race with the Soviet Union.
The scientists had no influence anymore on this decision. The President supported by the militaries decided to use the two developed bombs to end the war with Japan. In August 1945 the "Little Boy", an uranium-235 bomb, and the "Fat Man", a plutonium bomb destroyed Hiroshima and Nagasaki.
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The video above shows how devastating the effect of these bombs was. But it also suggests that Japan was already so distroyed by normal means that one may wonder whether the use of the nuclear bombs was really necessary. Anyway this decision led to the end of the war in Asia but at the cost of enormous amounts of human lives in Japan.
Was this a right decision?
After this demonstration of the power of these bombs the Soviet Union felt obliged to start the development of nuclear weapons, being afraid to be blackmailed by the US with their nuclear weapons. So did Great Britain and France. This was in principle the start of what later has been called “the cold war”. At some point the situation was such that if a nuclear war would have occured, it was quite likely that the world would have been destroyed.
We will come back to this situation later. It is questionable whether it was acceptable to take this risk.
Was this a right decision?
After this demonstration of the power of these bombs the Soviet Union felt obliged to start the development of nuclear weapons, being afraid to be blackmailed by the US with their nuclear weapons. So did Great Britain and France. This was in principle the start of what later has been called “the cold war”. At some point the situation was such that if a nuclear war would have occured, it was quite likely that the world would have been destroyed.
We will come back to this situation later. It is questionable whether it was acceptable to take this risk.