The merger wasn’t just the biggest ever, but also an event so rare that it challenges existing models for black hole genesis.

Astrophysicists have analyzed two merging black holes; the team's best models suggest that at least one, if not both, of the black holes shouldn't exist.

Scientists measure largest ever collision of two black holes - Scientists say the two black holes merged after colliding at speeds near the limit allowed by Albert Einstein’s theory of general relativ