Question

HOW MANY OTHER GALAXIES ARE THERE?WHAT IS AN BLACK HOLE?

Answer 1

Answer:

Black Hole : A black hole is a region of spacetime exhibiting gravitational acceleration so strong that nothing—no particles or even electromagnetic radiation such as light—can escape from it. ... This temperature is on the order of billionths of a kelvin for black holes of stellar mass, making it essentially impossible to observe.

How many galaxies : One Hundred billion Galaxies !

Answer 2

Answer:

• Most stellar black holes, however, lead isolated lives and are impossible to detect. Judging from the number of stars large enough to produce such black holes, however, scientists estimate that there are as many as ten million to a billion such black holes in the Milky Way alone.