A black hole is a point in space where there is extreme gravitational pull, so extreme that light itself cannot escape. The strength of gravity is so strong due to the fact that an immense amount of matter has been contained in a small space.
The existence of black holes was first theorized by John Mitchell in 1783. Mitchell accepted Newton’s laws of gravity and suggested that light escaping from the surface of a star would have its speed reduced due to the gravitation pull of the star, and therefore if a star’s gravitation pull was strong enough even light would not be able to escape. Using the approximate speed of light he reasoned that if an object was approximately 500 times the mass of the sun light would not be able…show more content… As this matter spirals into the black hole it creates what is known as an accretion disk, which accelerates and heats up emitting X-rays which can then be detected by astronomers.
Furthermore existence that black holes exist comes from the observations of astronomers of bursts of energy which are detected and then lost. An event horizon is an area of space around a black hole for which nothing can escape, once an object or any matter crosses this event horizon the gravity of the black hole will be too strong for it to escape. As a cloud of gas swirls and nears a black hole, the gases heat up and will emit x-rays. Astronomers have observed instances of several burts of x-rays being detected and then disappearing at areas where black holes are thought to be found. This may be caused by the gases emitting x-rays and then crossing the event horizon and disappearing forever. The observations of these bursts of energy are useful for astronomers in finding black holes.
”GX 339-4, illustrated here, is among the most dynamic binaries in the sky, with four major outbursts in the past seven years. In the system, an evolved star no more massive than the sun orbits a black hole estimated at 10 solar masses. “ 
However the strongest evidence of black holes comes from our