Neutron Star Mergers

When two neutron stars orbit each other, they slowly spiral inward as gravitational waves carry energy away. After millions of years they collide in a violent event called a kilonova.

In 2017, LIGO detected gravitational waves from a neutron star merger about 130 million light-years away. Telescopes worldwide watched the afterglow, confirming that these collisions forge much of the universe's gold, platinum, and uranium.