Astronomers have spotted the heaviest black hole pair ever seen — a duo weighing the equivalent of 28 billion suns. The black holes' combined mass is so great that they refuse to collide and merge.
The black hole binary, embedded inside the "fossil" galaxy B2 0402+379, consists of two enormous supermassive black holes circling each other at just 24 light-years apart, making them the closest black hole pair ever spotted.
