On the basis of General Theory of Relativity, a black hole can be considered as the area of space and nothing cannot escape from it. According to science, even light cannot escape from the black hole. A black hole is formed as a result of distortion of the space time that is caused by a very small particle. It is also said that the black hole is surrounded by some undetectable surface, as a result of which whatever goes in cannot come out. In other words, it absorbs everything without reflecting it, just like a black body in thermodynamics.
Now the question is “at what point would the earth become a black hole?“. This can be figured out from the theory of Schwarzschild Radius. Karl is a well known professor of astrophysics. He was sent to the Russian front when he joined the army. There was no pleasant movement in the World War I and most of the people believed that he concentrated on his survival. At that time, he collected some study material on Einstein’s Theory of General Relativity, which states that there are some heavy objects that twist the space time which results in what we comprehend as gravity. This point attracted Karl and he thought that heavier objects that twist the space time in such a way that sometimes, even light cannot escape from them. As he has nothing to do in the army he decided to work on the relation of the mass and space, to get more answers on the black hole.
Slowly, he started working on the theory of relativity and came up with an idea of calculating the area of the black hole. Based on that, he derived a formula, according to which the radius of the black hole can be calculated by doubling up the mass of the object and multiplying the result by the gravitational constant of the universe. And dividing the result by the square of the speed of the light. If we want it be described in the form of a formula, it can be shown as –
R = (2GM) /(c^2)
This formula can be explained in detail as, any massive object can become a black hole, if it is compressed to that extent. If any massive particle is pushed within the Schwarzschild Radius, then I could be compressed into the black hole. Hence, if we want to push the sun into a black hole, then the sun should be pushed into a radius of 3 km. Similarly, for the earth to turn into a black hole, it should be compressed into a radius of 8.7 mm. But, scientists felt that the stars that are nearly 40 times the sun failed to produce black holes after they collapsed. Recently, scientists felt that theoretical assumption is different from what happens practically.
Unfortunately, Schwarzschild Karl died of infection and his work proved very crucial in understanding the black holes. Today, there are some evidences that black holes exist, but the exact nature of black holes is not still known. Some scientists believe that the massive objects that fall into the black hole may emerge out somewhere else in the Universe.