Some of the heavier elements in the periodic table are created when pairs of neutron stars collide cataclysmically and explode, researchers have shown for the first time.
Light elements like hydrogen and helium formed during the big bang, and those up to iron are made by fusion in the cores of stars. Some heavier elements like gallium and bromine need something more, such as a supernova. Others—such as gold and uranium, which are the most neutron-rich—require a process called rapid neutron capture. Here, an atomic nucleus is bombarded with neutrons so it swells to an unstable size, but the whole thing happens so fast the element doesn't have time to split apart.
