What Is a Black Hole? | how black holes are formed.

What Is a Black Hole?

Black Holes are the region of space that has extreme gravitational even light can't escape from the gravitational force of black holes. Gravity near because the matter has been squeezed into a tiny point. Nothing can't escape from the Black Holes if it comes closer to it.
every Galaxy revolve around the Black Hole even our Milkyway galaxy,

There are four types of Black holes, they are stellar black holes, intermediate  black holes, supermassive  black holes, and miniature black holes,

How Black Holes are formed?

when a star which is at least three times more mass than our sun ran out of fuel and then dies and collapses in upon itself. and blast star outer layer into space and this explosion may sometimes lead to the formation of supernova if there is enough mass is left at the center after the explosion then the gravity at the core can continue to mass to be squeezed into an infinitely small point and lead to the formation of stellar black holes.

all supermassive black holes are located at the center of galaxies, the largest type of black hole is a supermassive black hole, this supermassive black has a mass more than thousands to billion times more than our sun.

intermediate black holes are formed by the collapse of the oldest stars or when two black holes collide with each other these intermediate black holes have a mass between supermassive black hole and stellar black holes.

  the first image  released by the Event Horizon Telescope on 10 April 2019,

 image of the supermassive black hole at the center of   Messier 87 is a supergiant 

elliptical galaxy which is 53 million light-years) from Earth 

who discovered black holes?

in the 18th century John Michell said about the objects which have strong gravitational force even light can't escape from that, but The first modern solution of general relativity that would characterize a black hole was found by Karl Schwarzschild in 1916, Black Holes are discovered by the great German physicist and astronomer by Karl Schwarzschild(9 October 1873 – 11 May 1916) in the year of 1916. Schwarzschild's solution Schwarzschild coordinates and the Schwarzschild metric leads to a derivation of the Schwarzschild radius, which is the size of the event horizon of a non-rotating black hole.

image of Karl Schwarzschild who discovered Black Holes

how many black holes are there?

scientists have found stellar black holes, intermediate black holes, supermassive black holes until now but we can't say how many black holes are present in this universe because the observable universe that we can see is 46 billion light-years if we want to say the particular number of black holes present this universe then we need to study the whole universe, but scientists estimated that there may be more than ten million to Billion black holes just only in our Milkyway galaxy. 

List of top 5 biggest black holes:

5. H1821+643 supermassive black hole.

4. S5 0014+81 supermassive black hole.

3. IC 1101 supermassive black hole.

2. Holmberg 15A supermassive black hole.

1. TON 618 supermassive black hole.