How many black holes are known to exists at the time

As of my knowledge cut off in 2 0 2 1 , there are no known black holes in the observ able universe . However , scientists have predicted that black holes will eventually form from the rem n ants of massive stars . The first direct detection of a black hole was made in 2 0 1 9 by the Event Hor izon T eles cope Coll abor ation . </s>