The first nuclear explosion on earth occured on July 16, 1945, in Alamagordo, New Mexico, as part of a test for the Manhattan project initiated by President Franklin Delano Roosevelt. The first nuclear weapon used in war was deployed less than a month later, when the United States dropped a Uranium 235 bomb on the Japanese city of Hiroshima on August 6, 1945, near the end of World War II. It killed about 140,000 men women and children. The United States managed to maintain a monopoly on nuclear weapons only for a few years. On August 29, 1949, the Soviet Union exploded its first nuclear bomb, escalating an arms race that would heavily influence international politics for the rest of the century.

This state of world affairs had its origins about 50 years earlier in the seemingly innocent studies of radioactivity which was first discovered by Henri Bequerel in 1896. In 1898, Ernst Rutherford characterized simple radioactivity...