... Szilard , Albert Einstein sent a letter to President Franklin Roosevelt informing him of the possibility of initiating a chain reaction - a self - sustaining fission reaction - in a mass of uranium , resulting in the release of a ... Numbers: A Cultural History provides students with a compelling interdisciplinary view of the development of mathematics and its relationship to world cultures over 4,500 years of human history.

Albert Einstein (14 March 1879 – 18 April 1955) was a German-born theoretical physicist best known for developing the theory of relativity. Einstein also made important contributions to quantum theory. His mass–energy equivalence formula E = mc2, which arises from special relativity, has been called "the world's most famous equation". He received the 1921 Nobel Prize in Physics for "his services t In 1939, a group of Hungarian scientists that included émigré physicist Leó Szilárd attempted to alert Washington, D.C. to ongoing Nazi atomic bomb research. The group's warnings were discounted. Einstein and Szilárd, along with other refugees such as Edward Teller and Eugene Wigner, "regarded it as their responsibility to alert Americans to the possibility that German scientists might win the race to build an atomic bomb, and to warn that Hitler would be more than willing to resort to such a weapon." To make certain the US was aware of the danger, in July 1939, a few months before the beginning of World War II in Europe, Szilárd and Wigner visited Einstein to explain the possibility of atomic bombs, which Einstein, a pacifist, said he had never considered. He was asked to lend his support by writing a letter, with Szilárd, to President Franklin D. Roosevelt, recommending the US pay attention and engage in its own nuclear weapons research. The letter is believed to be "arguably the key stimulus for the U.S. adoption of serious investigations into nuclear weapons on the eve of the U.S. entry into World War II". In addition to the letter, Einstein used his connections with the Belgian royal family and the Belgian queen mother to get access with a personal envoy to the White House's Oval Office. Some say that as a result of Einstein's letter and his meetings with Roosevelt, the US entered the "race" to develop the bomb, drawing on its "immense material, financial, and scientific resources" to initiate the Manhattan Project. For Einstein, "war was a disease ... [and] he called for resistance to war." By signing the letter to Roosevelt, some argue he went against his pacifist… Einstein played a major role in developing quantum theory, beginning with his 1905 paper on the photoelectric effect. However, he became displeased with modern quantum mechanics as it had evolved after 1925, despite its acceptance by other physicists. He was skeptical that the randomness of quantum mechanics was fundamental rather than the result of determinism, stating that God "is not playing at dice". Until the end of his life, he continued to maintain that quantum mechanics was incomplete.

I argue that to understand the life and work of Leo Szilard (1898–1964) we have to understand, first, that he was driven by events to numerous departures, escapes, and exiles, changing his religion, his language, his country of residence, and his scientific disciplines; second, that he was a man haunted by major moral dilemmas throughout his life, burdened by a sincere and grave sense of responsibility for the fate of the world; and third, that he experienced a terrible sense of deja vu: his excessive sensitivity and constant alertness were products of his experiences as a young student in Budapest in 1919. The mature Szilard in Berlin of 1933, and forever after, was always ready to move. I proceed as follows:After a brief introduction to his family background, youth, and education in Budapest, I discuss the impact of his army service in the Great War and of the tumultous events in Hungary in 1918–1919 on his life and psyche, forcing him to leave Budapest for Berlin in late 1919. He completed his doctoral degree under Max von Laue (1879–1960) at the University of Berlin in 1922 and his Habilitationsschrift in 1925. During the 1920s and early 1930s, he filed a number of patents, several of them jointly with Albert Einstein (1879–1955). He left Berlin in March 1933 for London where he played a leading role in the rescue operations for refugee scientists and scholars from Nazi Germany. He also carried out notable research in nuclear physics in London and Oxford before immigratin

The atomic bomb American program known as Manhattan Project has been studied in detail. Historians argue that the beginning of this program is rooted in the letter Einstein sent to American President Roosevelt in the summer of 1939. This article examines Einstein's activities before 1933 as radical pacifist in favor of the principles of universal disarmament and outspoken supporter of individual war resistance and the shift of this posture when Hitler came to power in 1933. In this context, we discuss the role played by nuclear physicists during the Second World War and Einstein's decision to promote the construction of an atomic weapon in the United States. Finally, the article analyzes Einstein's struggle against the atomic race during the beginning of the cold war.

‘Building the bomb’ looks at the origins of the Manhattan Project following the Einstein–Szilárd letter to President Roosevelt, and the journey to Hiroshima and Nagasaki. At the time of President Truman’s briefing on nuclear weapons, it was unclear how the war would end. The Americans may have overestimated the Nazis’ progress on their own nuclear project and underestimated that of Japan. Many of the experts who developed the bomb did not imagine it would be used on Japanese cities. Truman’s conclusion was that the bombs had averted other deaths, but in the aftermath of Japan’s surrender, how would America explain these new weapons to a triumphant but mystified populace?