From his home on Long Island, New York, German-born physicist Albert Einstein writes to President Franklin D. Roosevelt, urging "watchfulness and, if necessary, quick action" on the part of the United States in atomic research. Einstein, a lifelong pacifist, feared that Nazi Germany had begun work on an atomic bomb.
Einstein's theories of special and general relativity drastically altered man's understanding of the universe, and his work in particle and energy theory helped make possible quantum mechanics and early atomic research. As a German-born Jew, Einstein fled Germany for the United States after Nazi leader Adolf Hitler seized power in 1934.
In the summer of 1939, fellow expatriate physicists Leo Szilard, Eugene Wigner, and Edward Teller, profoundly disturbed by the lack of American atomic action, enlisted the aid of Einstein, hoping that a letter from such a renowned scientist would help attract Roosevelt's attention. Einstein agreed to the venture because of his fear of sole Nazi possession of the deadly weapon, a possibility that became especially troubling after Germany ceased the sale of uranium ore from occupied Czechoslovakia. After reading Einstein's letter, Roosevelt created the Uranium Committee, and in 1942 the highly secret U.S. and British atomic program became known as the Manhattan Project. Einstein had no role in the Allied atomic bomb program.
On July 16, 1945, an international team of scientists successfully tested the world's first atomic bomb in the New Mexico desert. Three weeks later, two U.S. atomic bombs were dropped on Japan, one on August 6 and one on August 9, resulting in the eventual deaths of more than 200,000 people. Albert Einstein deplored the use of the deadly weapon against the population centers of Hiroshima and Nagasaki, and after the war he urged international control of atomic weapons.