'Impossible' monster black hole involved in 'most massive' merger detected

A pair of black holes merged to form an intermediate-mass black hole, named GW190521, in a new gravitational waves detection. One of the black holes that were involved in the merger "shouldn't exist according to standard theories of how stars die," according to Swinburne University. -- Full Story: https://www.space.com/black-hole-intermediate-size-ligo-gravitational-waves-discovery.html Credit: Mark Myers, ARC Centre of Excellence for Gravitational Wave Discovery (OzGrav)/Swinburne University