How Many Black Holes are there in the Universe?

 

In a recent post, we explored the estimated number of planets in the universe which could be as high as 10²⁸ including rogue planets (not orbiting a star). The existence of black holes has been predicted for over a hundred years, but it wasn’t until 1964 when a black hole was actually detected (Cygnus X-1).

A black hole cannot be directly observed, but clear evidence for its presence can be detected as material is accelerated toward the black hole and is heated or by a black hole’s large mass can deflect light from stars. In the Astrophysical Journal this month, a paper provided an estimate of the black holes in the universe to be 40 x 10¹⁸ (40 quintillion) and they may make up 1% of the matter of the universe.

Image: NASA Goddard Media Studio - GMS: Black Hole Accretion Disk Visualization (nasa.gov)

Also see possible black hole image at M87.

Also see: Rogue Planets.