For just the second time, physicists working on the Laser Interferometer Gravitational-Wave Observatory (LIGO) have caught the gravitational waves of two neutron stars colliding to form a black hole.

The ripples in space time traveled some 500 million light-years and reached the detectors at LIGO, as well as its Italian sister observatory, Virgo, at around 4 a.m. E.T. on Thursday, April 25. Team members say there’s a more than 99 percent chance that the gravitational waves were created f