12/09/2026
The Black Hole That Wasn't Supposed To Exist
Two black holes merged and created something astronomers didn't think could exist. GW190521, detected by LIGO and Virgo on May 21, 2019, revealed a new black hole about 142 times the mass of the Sun.
The two black holes that merged were roughly 85 and 66 solar masses. The 85 solar-mass black hole fell right into the predicted pair-instability mass gap—a range where theory said black holes shouldn't form directly from stars. When they merged, they created an intermediate-mass black hole, filling in the missing middle between stellar-mass and supermassive black holes