Researchers have spent the past few years watching a black hole re-awaken roughly 300 million light-years away from Earth. And what they’ve documented challenges prevailing theories about black hole lifecycles. The groundbreaking observations are detailed in a study published on April 11 in Nature Astronomy.

"This rare event provides an opportunity for astronomers to observe a black hole's behavior in real time," said astronomer Lorena Hernández-García.

The black hole at the heart of galaxy SDSS1335+0728, located 300 million light-years away, was quiet for decades as it consumed little matter and was in a dormant state. But recently it suddenly lit up and began spewing out X-rays as it woke up and started feeding.