A black hole is the circular dark space that sits at the center of a galaxy which absorbs everything including light so nothing can be reflected or escaped from it. Around a black hole there is a surrounding surface, or event horizon, that marks the point of no return. A black hole is so named because nothing can come out it, similar to that a perfect black body in thermodynamics.

A recent study suggests that the supermassive black holes that sit at the center of most galaxies appear to be unaffected by dark matter.