Within our universe there are millions upon millions of galaxies. Humans have known the existence of stars since they have had eyes. The mystery does not lie within what we can see, but what we cannot see. The theory that black holes have existed is not new at all. All black holes are formed from the gravitational collapse of a star, usually having a great, massive, core. A star is created when huge, gigantic, gas clouds bind together due to attractive forces and form a hot core, combined from all the energy of the two gas clouds. This energy produced is so great when it first collides, that a nuclear reaction occurs and the gases within the star start to burn continuously. The hydrogen gas is usually the first time of gas consumed in a star and then other gas elements such as carbon, oxygen, and helium are consumed. This chain reaction fuels the star for millions or billions of years depending upon the amount of gases there are. The star manages to avoid collapsing at this point because of the equilibrium achieved by it. The gravitational pull from the core of the star is equal to the gravitational pull of the gases forming a type of orbit; however, when this equality is broken the star can go into several different stages. Usually if the star is small in mass, most of the gases will be consumed while some of it escapes. If the star was to have a larger mass however, then it may possibly Supernova, meaning that the nuclear fusion within the star simply goes out of control causing the star to explode. A black hole is one of the last options that a star my take. Not any star can become a black hole. For instance, the possibility of our sun becoming a black hole is highly unlikely, simply because it is too small. If the core of the star is so massive then it is most likely that when the star's gases are almost consumed those gases will collapse inward, forced into the core by the gravitational force laid upon them.