In Arlington National Cemetery lies Captain Jimmy Priestly Robinson of the US Air Force, Distinguished Flying Cross, Purple Heart, and Air Medal. It celebrates a pilot who flew into a hydrogen bomb’s mushroom cloud to give the world two new elements. By 1952, the world knew of 98 elements, the last six had been created at the University of California, Berkeley, mainly by chemist Glenn Seaborg, by bombarding nuclei with light ions or neutrons.