The idea of black holes has been around for a very long time and were predicted in Einstein’s theory of general relativity. Though scientists can’t observe black holes using x-rays, light, or electromagnetic radiation they can observe them by looking at their effect on the matter around them. For example, “If a black hole passes through a cloud of interstellar matter… it will draw matter inward in a process known as accretion.” While passing through this area the black hole will eat up any celestial bodies nearby and emit large amounts of gamma radiation. Scientists can observe their path of destruction to collect data.
A black holes creation begins with the death of a star at least three times the mass of the Sun collapsing in on itself in a huge super nova. One very interesting piece of information is that while the star is collapsing, “When the surface reaches the event horizon, time stands still, and the star can collapse no more – it is a frozen collapsing object.” Larger black holes are not created the same way. Instead they are formed by stellar collisions (i.e. a smaller black hole and a neutron star colliding to create a larger black hole). It was previously believed that no mid-sized black holes existed until further observations pointed to their existence and even their chain reactions of collisions leading to the creation of supper massive black holes like Sagittarius A*.
