There are billions of stars lighting the darkness of our universe, but the question lies in what happens when one of these enormous lamps burn out. Upon many speculations, one of the most fascinating is the black hole theory. When we say "Black Hole" we think of something from a science fiction movie thanks to Hollywood. We picture a big black hole in the universe as a "point of no return" that things disappear in. Television and movies have portrayed them as wormholes or time-traveling tunnels to another dimension, and as a cosmic vacuum cleaner sucking up everything in sight. However, although black holes can't be seen, they proved to exist by scientists by indirect evidence. It can simply be said that black holes are really just the evolutionary end point of massive stars. But somehow, this simple explanation makes them no easier to understand or less mysterious.
A black hole is "an extremely dense celestial body that has been theorized to exist in the universe" (Black hole, 1). It is believed that galaxy cores contain black holes because these areas are too dense and dark to be stars or clusters of stars. A black hole is a region of space that has so much mass concentrated in it that there is no way for a nearby object to escape its gravitational pull. Their density is infinite and thought to form from stars or other massive objects that collapsed from their own gravity. Einstein's general theory of relativity describes gravity as a curvature of space-time caused by the presence of matter. A black hole is a place where the curvature is so strong that a black hole is formed. As the density increases, the path of light rays emitted from the star are bent and eventually wrapped irrevocably around the star. Very massive or dense objects generate strong gravity. The most compact objects imaginable, black holes, are predicted by General Relativity to have such strong gravity that nothing, not even light can escape their grip, therefore appearing totally black.