In the simplest terms, what is the black hole? A black hole can be defined as a space region created by the collapse of a giant star, where gravity is so great that even light cannot escape its control. The final stage of star life varies depending on its initial mass. If it exceeds the Chandrasekhar limit, that is, 1. Then these stars turn into black holes. When a star ages, the fusion reaction inside its core creates tremendous pressure to balance the gravity generated by mass. But once it runs out of fuel, there is no reaction force, and only gravity will squeeze the star into a black hole. Such a large mass star collapses under its own gravitational force, causing the entire mass to be concentrated in a small volume called singularity, which is surrounded by the event horizon that we can see. Einstein\'s general theory of relativity interprets singularity as a point of infinite space Time curvature exists. The event horizon marks the boundary of the black hole, because from our point of view, any object passing through the event horizon no longer exists, when it is pulled into the back hole by huge gravity. According to the mass, magnetic field and spin of black holes, black holes are divided into three types. On the basis of mass, black holes are divided into miniature black holes, star black holes and super black holes. Huge black hole1. Miniature black hole: It is believed to have formed during the big bang and there is no evidence that it may exist during the evolution of the universe. The mass of these black holes will be much smaller than the sun, and they are only formed during the Big Bang due to extreme external pressures that compress the mass to create a singularity. 2. Star black hole: this type of black hole is due to the death of a huge star. 3. Supermassive black holes: These types are the largest of these three black holes. Scientists believe that these black holes, which occupy the center of galaxies, will increase in size as they extract more and more materials from the nuclear hearts of galaxies. Unlike the outside of the Galaxy, the inner region is packed with stars, creating favorable conditions for the growth of supermassive black holes. The size of these black holes is about a hundred thousand solar masses. Depending on the spin and magnetic field of the black hole, different methods can also be used to classify the black hole. This classification is based on Einstein\'s general theory of relativity. 1. Schwarzski black hole: the simplest of the three categories, only theory exists. It has neither a magnetic field nor a spin. This type is proposed by Karl Schwarzschild, which is characterized by a singularity and an event horizon. 2. Kerr black hole: this type of black hole has spin and magnetic field, and is the most common black hole type in space. These uncharged black holes have characteristic rotations around the central axis. The Kerr black hole is named after Roy Kerr, the scientist who proposed its existence. It has a circular singularity and two event horizons ( One inside and one outside), ergo- Ball and static limit. The Ergo- The sphere is an oval area outside the outer horizon, where space- The time continuum rotates with the rotation of the black hole. The rotation of this space The time continuum is called Lense-Thiring Effect. Space is normal beyond the static limit. Particles moving through ergo- The sphere has the opportunity to escape by gaining energy from the rotational energy generated by the rotation of the black hole. But once across the horizon of the event, there is no return trip. Another interesting fact about this black hole is the closed time like a path. 3. Reissner- Nordstrom black hole: This group of black holes is characterized by singularity and two event horizons without rotation. Because all the identified black holes have rotations, this group has only a theoretical basis. In the absence of black hole light, scientists rely on indirect methods to detect the existence of black holes. Star objects close to the event horizon begin to rotate with it at a very high speed and are therefore heated. This forms an accumulation disk around each visible black hole. Double stars also provide evidence for the existence of black holes. When one of them becomes a black hole, it will tear off a part of its companion star and form an accumulation disk around the back black hole. Quite a few massive black holes have been discovered. Black holes found in the M87 and OJ 287 galaxies of the Cancer constellation are examples of supermassive black holes. Cygnus X - 1 is the star black hole found in the Swan seat.