The USS Cygnus orbiting around a black hole. A black hole is a peculiar region of the space filled with so much dense matter that even the light cannot escape from the gravitational field. As such, everything orbiting near a black hole is attracted and eventually falls in it. A massive black hole with a mass equal to millions of solar masses is at the center of our galaxy, the Milky Way. Black holes are also formed when after the final explosion of a very massive star its remnant collapses under its own gravity.