Sleeping black hole swallows star and is now bursting out X-rays
Studying the X-rays being emitted can help astronomers understand how the biggest black holes in the universe are formed

Almost four billion light years away, a supermassive black hole named Swift J1644+57 is hibernating.
Like almost 90 per cent of the biggest black holes in the universe, Swift J1644+57 is dormant, which means it’s not actively looking for matter to gobble up into its nearly bottomless pit of gravity.
And, therefore, it’s especially black — it’s not radiating light or anything else for that matter.
Black hole fireworks
But sometimes, while a black hole is hibernating, a meal just happens to fall into its lap. A wandering star ventures too close to the black hole’s gravitational reach and spirals hopelessly towards it.
“The ensuing feeding frenzy, known as a tidal disruption event, sets off spectacular fireworks,” according to the University of Maryland.