We know the newton law of physics that everything has equal and opposite reaction .When the rocket goes up it gives out a lot of gases in the downward direction .In the same way a hot body give out a lot of radiations and loses its energy. We can say how it is possible that a black hole swallow everything even light but does not give out or emit anything . The scientists assumed this before that black hole does not emit anything and thus violates the laws of physics but later they found out that it does emit. Stephen hawking named the radiations coming out of the black hole as Hawking radiations .This can be explained by the second law of thermodynamics, that in a closed diordered system the entrophy incerases. A blackhole consist of a lot of energy and the entrophy forces matter out of a black hole. Einstein equation tell us that energy is associated with matter.(E=mc^2). When energy is converted into matter it always comes as matter and antimatter i.e a electron and positron .Stephen hawking explained that universe is the collection of these particle and antiparticle and they anhiliate back into energy as a electron and positron cannot stay alone. But to his surprise he found that at the boundary of a black hole(event horizon) the particle with negative mass is pulled inside, emmiting out the particle with positive mass. These positive particle are the radiations coming out of a black hole .This are hawking radiatioins that ressembles heat. There is a inperceptible microscopic glow at the boundary. He also founded that the particle with negative mass that is going inside the black hole is decreasing the mass of black hole. Thus black hole cannot be the end of something but can be a beginning of something. A black hole chew up the universe and emit out jets of energy.There is a enormous amount of activity going out around a black hole.
Shristi uniyal 