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the letter that einstein wrote to roosevelt

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Albert Einstein Old Grove Road Peconic, Long Island August 2nd, 1939 F.D. Roosevelt President of the United States White House Washington, D.C. Sir: Some recent work by E. Fermi and L. Szilard, which has been communicated to me in manuscript, leads me to expect that the element uranium may be turned into a new and important source of energy in the immediate future. Certain aspects of the situation which has arisen seem to call for watchfulness and if necessary, quick action on the part of the Administration. I believe therefore that it is my duty to bring to your attention the following facts and recommendations. In the course of the last four months it has been made probable through the work of Joliot in France as well as Fermi and Szilard in America--that it may be possible to set up a nuclear chain reaction in a large mass of uranium, by which vast amounts of power and large quantities of new radium-like elements would be generated. Now it appears almost certain that this could be achieved in the immediate future. This new phenomenon would also lead to the construction of bombs, and it is conceivable--though much less certain--that extremely powerful bombs of this type may thus be constructed. A single bomb of this type, carried by boat and exploded in a port, might very well destroy the whole port together with some of the surrounding territory. However, such bombs might very well prove too heavy for transportation by air. In view of this situation you may think it desirable to have some permanent contact maintained between the Administration and the group of physicists working on chain reactions in America. One possible way of achieving this might be for you to entrust the task with a person who has your confidence and who could perhaps serve in an unofficial capacity. His task might comprise the following:a) to approach Government Departments, keep them informed of the further development, and put forward recommendations for Government action, giving particular attention to the problem of securing a supply of uranium ore for the United States.b) to speed up the experimental work, which is at present being carried on within the limits of the budgets of University laboratories, by providing funds, if such funds be required, through his contacts with private persons who are willing to make contributions for this cause, and perhaps also by obtaining co-operation of industrial laboratories which have necessary equipment.I understand that Germany has actually stopped the sale of uranium from the Czechoslovakian mines which she has taken over. That she should have taken such early action might perhaps be understood on the ground that the son of the German Under-Secretary of State, von Weizsacker, is attached to the Kaiser-Wilhelm Institute in Berlin, where some of the American work on uranium is now being repeated. Yours very truly, Albert Einstein

In the first paragraph Einstein emphasizes the main characteristic of nuclear reactions, namely, that they release a very high amount of energy, and since some scientists such as Fermi and Szilard have found ways to manipulate it, he feels the need, along with others, to appeal to the president of the united states of America to begin a campaign to allow greater state involvement aimed at advancing such research. Nuclear energy, in particular, is the energy released by nuclear reactions and radioactive decay. Studies of decay began in 1896 by Henri Becquerel and Marie Curie while working with phosphorescent materials. Becquerel suspected that the glow produced by cathode ray tubes once they were turned off might be associated with X-ray-induced phosphorescence. So he took various phosphorescent salts, which he wrapped in a photographic plate. All the salts did not leave an imprint in the photographic plate, except for uranium salts. The discovery of nuclear fission occurred in 1938, by Strassman and Hahn, following Albert Einstein's studies of relativity. In fact, the latter understood that energy and mass are two manifestations of matter and equated them with the formula E=mc^2. With that formula, Strassman and Hahn, were able to calculate what the binding energy was that would allow any nucleus to be divided into its nucleons.In fact, any atom has a total mass that is less than the sum of its individual nucleons, and by calculating this difference, the value of energy needed to trigger a chain reaction can be determined. The characteristics of uranium, already identified by Becquerel and Curie, but also confirmed in 1938 by Strassman and Hahn, were highly qualified for this purpose. �=��

Einstein's main objective was to urge the government to establish a committee that could bring together and supervise the scientists who were working on these studies, in order to facilitate and augment the efforts made to realize the project. Thus, in the fall of 1939, Roosvelt decided to immediately start an Uranium Committee, with the purpose of studying the possible military applications of the uranium fission process. Also known as the S-1 Executive Committee, the project laid the groundwork for the Manhattan Project by initiating and coordinating early research efforts in the United States and collaborating with the Allois Tube Project in Britain. While recognizing that the science was unproven and that the nuclear chain reaction was no more than a theoretical possibility, it predicted that nuclear energy could be used as propulsion for submarines and that an atomic bomb "would provide a possible source of bombs with far greater destructiveness than anything now known." The committee recommended that the government purchase 50 tons of uranium oxide and 4 short tons of graphite for chain reaction experiments.

In the first part of the paragraph Einstein shows that he is aware of the work of scientists who are working on the study of nuclear fission, in particular he mentions: -Frédéric and Irène Joliot-Curie, who in 1933 set up artificial radioactivity, namely the transformation of chemical elements into others due to bombardment with alpha particles; in particular, as they enter the nucleus, these particles make it unstable, consequently the substance becomes radioactive. -Enrico Fermi, who in 1934 used neutrons instead of alpha particles as projectiles to bombard chemical elements, with the advantage that the neutron, being neutral, does not suffer repulsion from the nucleus by electromagnetic forces. In particular, fermi used slow neutrons. Einstein, in the second part of the paragraph, is also well aware of an upcoming and high use of nuclear power as a source of energy, because it can trigger a chain reaction through fission processes that forms transuranic elements. In 1938 Lise Meitner and Otto Frisch interpreted the results of experiments conducted by Otto Hahn and Fritz Strassmann, particularly those of the formation of transuranic elements following bombardment of uranium atoms. The uranium nucleus energy from the neutron deforms because coulombic repulsion between protons of the same charge overrides attractive nuclear forces. The nucleus splits into two fragments that shoot off releasing a very high energy, that is, the total binding energy of the components of the starting uranium nucleus and that of the two lighter nuclei.

In the last part of the letter, it becomes clear why Einstein is so determined to want to speed up the construction of the reactor, in fact the progress made in Germany, such as the acquisition of uranium mines in Czechoslovakia and the establishment of an institute dedicated to studies of the fission mechanism, worried many scientists, who, perhaps naively, pushed for it to get ahead of the Germans. The Kaiser Wilhelm Institute in Berlin played a very important role regarding the studies of Nazi Germany, in particular welcoming the brightest German minds, such as Heisenberg, who was its director until 1945. Here the Uranverein was born, a specific council whose charge was to exploit possible developments in nuclear physics for war purposes. In particular, the Team headed by Heisenberg discussed the details of the U.S.S. American atomic bomb, and together with the other scientists, he was asked to advise on judging damage reports and effects. It became clear from the results how Heisenberg was totally unaware of the principles needed to trigger the atomic explosion, and how, instead, he had greatly overestimated the critical mass of highly enriched uranium needed to initiate the nuclear chain fission reaction: 13 tons assumed versus the approximately 40 kilograms actually sufficient for the purpose, Heisenberg's calculations, therefore, would have made it technically impossible to build such a device. In all this it should be noted that Einstein's fear turned to regret after he learned of Germany's surrender on May 8, 1945: "If I had known that the Germans would not succeed in building the atomic bomb, I would never have lifted a finger." "If I had only known, I would have been a watchmaker. The difference between genius and stupidity is that genius has its limits, while stupidity does not."

In the first part of this paragraph it is confirmed that many scientists were aware of the effects of using a new weapon based on the nuclear fission mechanism, in fact we know that Einstein had written the letter at the request of Szilard, who together with Fermi had theorized about a possible ripple effect. Szilard was the first to act, trying to convince the U.S. government to arrange for the wartime use of the new bomb that the discovery of fission hinted at. News that the Nazis had suddenly banned the export of uranium from mines in occupied Czechoslovakia convinced Szilard that Germany was preparing to build the bomb. Szilard was, however, in 1939 an unknown immigrant without a steady job and, to interest the government in his idea, he had to seek help. He thus turned to the man who was considered the greatest living physicist: Albert Einstein. Einstein wrote a letter addressed to President Roosevelt on August 2, 1939, in which he informed him of the possibility of building the new type of bomb, of the serious suspicions about Germany's intention to initiate such construction, and urged him to begin the necessary research as soon as possible. In the second part Einstein emphasizes the destructive force such a bomb could have in the world, in particular it could have disintegrated a military port or a city, the fact that the bomb might be too heavy for air transport was considered, but the government's call for action would surely obviate this problem.

From Einstein's perspective, the main functions of the committee were mainly two: - To keep the government up to date regarding possible research developments and to be a speaker for requests that scientists involved in the project want to make to facilitate developments, such as securing an influx of uranium needed to build the reactor. - Increasing funding for the project through campaigns that also target private individuals and asking for the cooperation of universities and industrial laboratories that can facilitate the production of reactor components. The latter was immediately taken care of, in fact experiments with uranium fission were then done at universities and research institutes in the United States, such as the Berkeley Radiation Laboratory or the Carnegie Institution. At Columbia, while Fermi and Szilard investigated the possibility of creating a nuclear chain reaction, Dunning considered the possibility, put forward by Niels Bohr and John A, Wheeler, that it was the rare isotope 235 that was primarily responsible for fission. He had Alfred OC Nier of the University of Minnesota prepared samples of uranium enriched in uranium-234 , uranium-235 and uranium-238 using a mass spectrometer. These experiments were ready in February 1940, and scientists such as Dunning then carried out a series of experiments. They showed that uranium-235 was indeed the main culprit in slow neutron fission, but they were unable to determine accurate neutron capture cross sections because their samples were not sufficiently enriched. Briggs reported to Watson on April 9 that it was doubtful that a chain reaction could be initiated in uranium without uranium enrichment, and so he urged that research on isotope separation technology be undertaken.

PRESIDENT ROOSEVELT'S REPLY TO DR. EINSTEIN WHITE HOUSE WASHINGTON OCTOBER 19, 1939 MY DEAR PROFESSOR: I WANT TO THANK YOU FOR YOUR RECENT LETTER AND FOR THE EVEN MORE INTERESTING AND IMPORTANT ATTACHMENT. I FIND THIS DATA OF SUCH IMPORTANCE THAT I HAVE CONVENED A COMMITTEE CONSISTING OF THE HEAD OF THE BUREAU OF STANDARDS AND A SELECT REPRESENTATION OF THE ARMY AND NAVY TO INVESTIGATE THOROUGHLY THE POSSIBILITIES OF YOUR PROPOSAL CONCERNING THE URANIUM ELEMENT. I AM PLEASED TO SAY THAT DR. SACHS WILL COOPERATE AND WORK WITH THIS COMMITTEE AND I FEEL THAT THIS IS THE MOST PRACTICAL AND EFFECTIVE METHOD OF DEALING WITH THIS MATTER. PLEASE ACCEPT MY SINCERE THANKS. VERY SINCERELY YOURS, FRANKLIN ROOSEVELT