Neutron star mergers may create much of the universe’s gold

The occasional merger of neutron stars literally shakes the universe by sending out gravitational waves (illustrated above), but these events may also be the main source of gold and other heavy elements in the Milky Way, a new study suggests.

Some elements—such as gold, europium, and many others heavier than iron—are forged by a process dubbed rapid neutron capture, in which an atomic nucleus quickly absorbs a series of neutrons to reach a stable form before it radioactively decays. But debate rages among scientists as to where the largest proportion of such elements in the universe come from: Some suggest it happens deep within collapsing supernovae, and others propose that it occurs during the relatively rare but spectacular merger of neutron stars.