What is a Black Hole??

You all might have heard the term ‘black hole’. Have you ever wondered actually what is it. It is not a black dot on a sheet of paper or something crap like that. A black hole is a gravitational singularity. So what is a singularity, a point at which a function takes an infinite value, especially in space-time when the matter is infinitely dense. In the centre of a black hole is a gravitational singularity.
Now let us find out how black holes are formed.
Black holes of stellar mass are expected to form when very massive stars collapse at the end of their life cycle. After a black hole has formed, it can continue to grow by absorbing mass from its surroundings. By absorbing other stars and merging with other black holes, supermassive black holes of millions of solar masses may form. There is a general consensus that supermassive black holes exist in the centres of most galaxies. Let me tell you a solar mass is the mass of the sun. So just think how heavy black holes are. A star with a mass greater than 20 times the mass of our Sun may produce a black hole at the end of its life. In the normal life of a star, there is a constant tug of war between gravity pulling in and pressure pushing out.

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