What is Hawking Radiation ?

To know about hawking radiation, first you will need to have a basic idea about “Black Holes”. When a massive star dies, it leaves a dense remnant core. If the mass of that core is  3 times more than the mass of our own sun then the gravitational force overwhelms all the other forces and because of this a Black hole is formed. A black Hole isn’t just an empty space instead it is a space where a lot of things are packed into a very small area. Just think about it, A star that is 10 times bigger than our sun and then it being squeezed into a small area whose diameter maybe as small as a city ! The gravity in the black hole is so Strong that even light and X-rays cannot escape !

Until 1974 when Stephen Hawking put down the theory of Hawking Radiation, it was believed  that the black hole doesn’t emit or radiate any kind of energy. But this changed because of the Hawking radiation theory which was made by combining Quantum mechanics and Einstein’s general theory of relativity.

According the principles of quantum mechanics, for every particle there is a “Anti particle” (Just like there is an anti-virus for a virus). Both these particles always form in pair and they destroy & cease each other almost immediately just after they are formed !. But around the Event horizon of the black holes the things change, if this pair forms into existence near the event horizon then One of the particles could “fall” Into the black hole and the another one would just escape into the space.  The one which “falls” into the black hole effectively has negative energy and the escaping one would possess positive energy which is referred to as Hawking Radiation. Due to the presence of hawking radiation the black hole will lose mass and will continue shrinking until it loses all of it and “evaporates”….

Till now it is not clear what an Evaporating black hole looks like and what are its characteristics. But it is sure that the Hawking radiation would contain high energy particles and gamma rays and such radiation is invisible to the eyes. Its also possible that these radiations might be a hadronic fireball which could degrade the gamma rays and particles of less energy which would make an evaporating black hole visible !