In February 1941, while working on a 60-inch (152.4 cm) cyclotron at the University of California/Berkeley Rad lab, physicist Glenn Seaborg bombarded uranium with deuterons, the nuclei of the hydrogen isotope deuterium. The result? A new element number 94, which Seaborg named “plutonium” after our solar system’s ninth planet (at the time). Seaborg gave this new discovery the chemical name “Pu”, in reference to a child’s description of a foul odor.
Shortly after this breakthrough, Seaborg and fellow physicist Emelio Segre discovered that one particular isotope of the new element, plutonium 239, underwent fission when struck by neutrons, releasing a massive amount of energy. This energy, Seaborg theorized, could be harnessed for use in an atomic bomb. Ultimately it was.
Manhattan Project workers produced plutonium at Hanford, Washington. Scientists at Los Alamos, New Mexico used Hanford's plutonium and harnessed its power to create both the Gadget, the world’s first atomic test device, and Fat Man, the plutonium-fueled atomic bomb dropped on Nagasaki, Japan on August 9, 1945.