W. Yuan

In a dark corner of the Milky Way, a natural metronome is at work. Every 8196 seconds, about 2 hours and 16 minutes, X-ray light flares on the surface of a neutron star. The star EP J171159.4-333253 pulls gas from a neighboring star, and this gas, falling inward, accumulates on its surface.

Massive stars end their lives in a colossal explosion, which Fritz Zwicky called a supernova. The core crushes down into a black hole or a neutron star.