The term black hole is of very recent origin.It was coined in 1969 by the American scientist John Wheeler as a graphic description of an idea that goes back at least two hundred years. At that time there were two theories about light. One was that it was composed of particles ;the other was thatb it was made of waves. We now know that really both theories are correct. By the wave/particle duality of quantum mechanics, light can be regarded as both a wave and aparticle. Under the theory that light was made up of waves, it would respond to gravity. But if light wre composed of particles, one might expect them to be affected by the gravity in the same way that cannonballs, rockets, and planets are.
On the assumption, a Cambridge don, John Michell, wrote a paper in 1783 in the Phiosophical Transaction of the Royal Society of London.In it, he pointed out that a star that was sufficiently massive and compact would have such a strong gravitational field tha light could not escape. Any light emitting from the surface of star would be dragged back by the stars gravitatinal attraction before it could get very far.Michell suggested that their might be large number of stars like this. Although we would not be able to sewe thembecause light from them would not reach us, we would still feel their gravitational attraction. Such objects are what now call black holes, because that is what they are black void in space.

Einstein proposed the theory of General Relativity in 1915; even then it was long time ago implications of the theory for the massive stars were worked out. To understand how a black hole might be formed, we first need to understand the life cycle of a star.the star is formed when large amount of gas, mostly hydrogen starts to collapse in itself due to its gravoitational attraction. As it contracts, the atoms of gases collide with each other more and more frequently and at a great and great speed- the gas heats up. Eventually gas willbe hot that when hydrogen atoms gets collide they no longer bounce off each other but instead merge with each other to form helium atoms. The heat is realeased in this reaction, which is like a controlled hydrogen bomb, is what makes the star shine. This additional heat also increases the pressure of the gas until it is sufficient to balance gravitational attraction, and the gas stops contracting. It is a bit like a ballon where there is a balance between the pressure of the air inside, which is trying to make the ballon expand, and the tension in the rubber, which is trying to make ballon smaller.
The star will be remain stable like this for a long time, with the heat of the nuclear reaction which is balancing the gravitational atraction. Eventually, however, the star wil run off its hydrogen and other nuclear fuels. And paradoxically, the more fuel the star starts off with, the sooner it runs out. This is because the more massive star is ,the hotter it needs to be to balance its gravitational attraction. And the hotter it is, the fast it will use up its fuel. Our sun has got enough fuel for another can use up their fuel is as little as hundred million years, much less than the age of the universe. When the star runs out its fuel, it will start to cool off and so to contract. What might happen with it was only first understood till the end of 1920s. Here is mini-biography of Albert Einstein:

In 1928s Indian gradute student name Subramanyam Chandrasekhar set sail to study in England in Cambridge with Arthur Eddington th expert in general theory of relativity. There is a story that ajornalist told Eddington in th early 1920s that he had heard that there are three people in the world who understood the general relativity. Eddington replied, "I am trying to think who the thrid person is."
During his voyage from India, Chandrasekhar worked out how big star could be still seperate itself against its own gravity after it had used its all fuel. The idea was this: When the star becomes small, the matter particles get very near each other. But the Pauli exclusion principles says that two mater particles cannnot have both the same position and the same velocity. The matter particles must therefore have very different velocities. This makes them move away from each other ,and so tends to make the star expand. A star can therefore maintain itself at a constant radius by the balance between the attraction of gravity and the repulsion that arises from the exclusion principle, the just as earlier in its life the gravity was balanced by the heat.
Chnadrasekhar realized, however, that ther is a limit to the replusion that exclusive principle can provide. The theory of relativity limits the maximum difference in the velocities of the matter particles in the star to the speed of light. This meant that when the star got sufficiently dense, the replusion caused by the exclusion principle would be less than the attraction of gravity. Chandrasekhar calculated that a cold star of more than about one an a half mass of the sun would not be able to support itself against its own gravity. This mass is now known as the Chandrasekhar limit. According to theChandasekhar Limit, if a star crosses the chandrasekhar limit ;then it will be different to the star who is not crossing the chandrasekhar limit.

1. Star crossing Chandrasekhar limit:
• Blackhole
• Nebula
• Whitehole
2. Star not crossing Chandrasekhar limit:
• Pulsars
• White Dwarfs
• Magnetars

Here is a mini-biography of Subramanayam Chandrasekhar:

Blackhole was not just theory for the scientist who wee working on the discovery of blackhole.Later on In 20s the Blackhole was totally proved by the every scientist of the world ,but now also the one concept of blackhole was remaining which was the image of Blackhole. By the James Webb Telescope this was possible in year 2021 and now finally the journey of the blackhole got complete ,but this is not the full knowledge of the blackhole. These blackhole are also connected to the whiteholes which together forms the huge wormhole. These wormholes are mysteries because they helpful for us to travel the other galaxies in a second. According to m eit would be helpful for every human being in future ,if we will be able to understand the concept of wormhole. Share your thoughts on this topic on my youtube channel "R.M KNOWLEDGE ART". this is the link to vist the page: Click here to Visit
A person who defeated the death and the people who thought that is a ill and mentally disturbed. He tought the world to live with great number of confidence in their mind whether anybody is liking you or not. --Stephen Hawkins

Now, Here is a short video on Stephen Hawkins:

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