E. Parent

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.

Pulsars are rapidly spinning neutron stars that emit radio pulses like a lighthouse. But some of them stay silent almost all the time, occasionally emitting a single pulse. Such objects are called rotating radio transients (RRATs). They were discovered nearly twenty years ago, but they remain a mystery.