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Niels Bohr

Born in Copenhagen, Denmark on October 7, 1885, Neils Bohr made several contributions to the understunding of atomic structure and quantum mechanics. He received his Ph.D. in physics from the University of Copenhagen in 1911 after which he moved to England to study under Ernest Rutherford. Based on an earlier theory by Rutherford that the atom consisted of a positively charged nucleus, with negatively charged electrons orbiting around it, Bohr published a theory about the structure of the atom in 1913. Bohr expanded on Rutherford's theory, suggesting that electrons only travel in successively larger orbits and that the outer orbits hold more electrons than the inner ones. He also proposed that the outer orbits determined the atom's chemical properties and that atoms emit radiation when an electron jumps from an outer orbit to an inner one, emitting light. In 1922, Bohr won the Nobel Prize in Physics for his work on the structure of atoms.

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In 1916, Bohr became a professor of physics at the University of Copenhagen and in 1920 was named the Director of the "Institute of Theoretical Physics" at the university. Being of Jewish origin, Bohr fled Copenhagen in 1943 to escape the Nazis. He later accompanied a British research team to Los Alamos, New Mexico, where he advised scientists developing the first atomic bomb. After the end of the war, Bohr returned to Copenhagen to promote peaceful and rational atomic policies. In 1944, Bohr tried to persuade Winston Churchill and Franklin D. Roosevelt of the need for international cooperation on the control of nuclear weapons. He received the first US "Atoms for Peace Award" in 1957.