Learn why a black hole is becoming active and why experts still can't explain the source of its regular, periodic pattern of X-ray energy flashes.

Black holes are known for their powerful gravity, which can pull in nearby gas, dust, and even stars. When this material gets too close, it heats up and forms a glowing disk around the black hole, called an accretion disk. But sometimes, black holes go through long periods where they aren’t feeding on anything—and that’s when they appear quiet.

A previously dormant supermassive black hole in the galaxy SDSS1335+0728, located roughly 300 million light-years from Earth, has stunned astronomers by bursting into life with a series of intensely powerful X-ray eruptions.