apse will occur. Once gravity exceeds the other forces, the star will fall in on itself in a few hours.When the size of the collapsing star falls below what is called the Scharzschild Radius, the escape velocity becomes equal to the light. When not even light canescape from the surface, the star is said to be inside a black hole. Theorems by Roger Penrose and Stephen Hawking show that, according to general relativity and similar theories of gravitation, a singularity or edge to the space-time continuummust occur. It is believed, but has not been proved, that everything inside a blackhole will hit the singularity and be utterly destroyed within a few microseconds;however, some claim that matter and energy may reappear in another universe. The collapse of a star or a dense cluster of stars can release large amounts ofenergy, perhaps 10% of the total rest-mass energy of the system if the collapse isnonspherical. Most of the energy will probably be emitted as gravitational waves.Matter falling into a black hole already formed can also release electromagneticenergy. This is a possible source of X rays from Cygnus X-1 in our galaxy andof visible light radio waves from quasars and from certain other distant galaxies.The universe as a whole may also undergo gravitational collapse. The universe is presently expanding as distant galaxies move apart, but if they do no have escapevelocity relative to each other they will eventually fall back together and bring the universe to an end. Whether this will happen depends on the density of matter inthe universe, which is not precisely known.(Asimov 255) For the past couple of centuries astronomers have done many things to try to unlock the mystery of these natural wonders called black holes. The curiosity of many scientists has motivated them to use every means possible to do this. If there is one scientist who, in the last couple of decades, has contributed more towards thi...
