Scientists scouring the cosmos for signs of a rare explosion may have stumbled upon something even more remarkable: a gargantuan black hole "switching on" in the early universe, going from dim to tremendously bright in a cosmic blink of an eye.
The black hole, dubbed J221951, is estimated to sit about 10 billion light-years from Earth, meaning the cosmic monster turned up its lights when the universe was roughly one-quarter of its current age. Despite this vast distance, the black hole brightened so intensely that astronomers initially mistook it for a stellar explosion less than 1 billion light-years away.
