Abstract :
The historical back ground of different to settle down to a neutron star equilibrium configuration. The contraction would continue without end beyond the event horizon and ultimately what is left is nothing but a gravitational field so intense so intense that no matter or signals of any kind are allowed to escape to infinity and bring information about the fate of the collapsing matter. The body has fallen deep inside the event horizon. Event horizon is one way membrane. Inside it, the gravitational field is so powerful that nothing can escape outside. Even light emitted at any point inside the event horizon is dragged inward irrespective of the direction of emission. However, light emitted at any point outside the event horizon can escape to infinity if it is suitably aimed at. Because of the nature of black holes they can properly detected only through the effects of their gravitational field on the closely surrounding objects provided they can be observed.