What are black holes? You just imagine a void of very very small in size which is enormously dense which engulf the objects which comes with in its surroundings. Here a simple explanation for a black hole. Black hole is a star which collapsed under its own mass few times and it becomes more compact every time. Because of its enormously high density this endless chasm sucks everything with in its vicinity and absolutely nothing can escape from its attraction.
The name 'BLACK HOLE' was coined by John Weeler, a famous astrophysicist of American origin. While deriving the theory of relativity Albert Einstein told about the black holes but none of the scientist thought about it.
While we are discussing about a black hole, we are fully against the
For your convenience let me explain to you with sun as an example. If our sun has to be changed to be a black hole the following things has to be take place. First the diameter of the sun has to be compressed to make it a ball of one kilometer radius (now the diameter of Sun is 1392000Km) while doing so its density will be increased and hence it’s mass will be equal to 1000000000000000000000000000000 Kg. Similarly if you convert earth in to a black hole it will be a ball of 1cm radius and of mass 10 power 25Kg( 1 followed by twenty five zeros) Now the earth's diameter of earth is 12756Km.
Now I hope you have a brief outline about a black hole. Now let’s go through the general process of creation of black hole.
Stars are of huge balls of gases mostly Hydrogen. Their energy is derived from nuclear fusion of Hydrogen into Helium (Nuclear fusion is a clear source of energy occurs in very high temperature and pressure). Once the stars weight and the energy produced balances each other then they will be stable. They will not collapse as long as the energy production takes place the will be stars. But once the energy production reduced due to lack of fuels the stars implodes in on itself simultaneously its radius also reduce. After few collapses their radius reduced to a greater extent and becomes a black hole.
Here the problem for astrophysicist is discovering black hole in the universe. Since they are not visible we can not find them as visible object. But they can be finding out by using a different phenomenon of binary stars.
Binary stars are the two stars rotation around each other. If one star become a black hole the other will tumble down and will be absorbed, while it is absorbed there is a disc of dust called accretion disc form around the hole. The very hot matter inside the black hole is extremely accelerated and hence releases strong radio waves. Using these radio waves we can find the black hole. The velocity of disc rotation is directly proportional to the mass of the black hole.
According the scientists the galaxies rotate like a centrifuge. The total mass of the stars and other objects at the centre holds the stars in the outer edges hold them in place. Hence we can arrive at this following conclusion that the mass of all matter of stars is not sufficient to hold the very distant stars therefore some invisible gigantic black holes at the centre are exert force on the stars at the outer
Here a point to note: The time stops inside a black hole which is a unique and very important point in the space and time relationship.