Black holes are objects of the universe that attract the interest of many astronomers. Black holes, space objects whose existence is predicted by the general theory of relativity. Gravitational collapse is a catastrophically fast compression of a star under the influence of gravitational forces (gravity).
External structure of a black hole
A region has associate degree external field, the properties of that area unit determined by the mass, torsion associate degree probably associate degree electrical charge if the star collapses with an electrically charged star. On the large distances, the sector of a region much doesn't dissent from gravitation fields of usual stars, and movement of different bodies interacting with a region on the large distance submits to laws of mechanics of Newton. The field is therefore robust that it cannot emit any light-weight in the least, therefore it looks black.
Catastrophic gravity by compression (collapse) can end, in particular, the evolution of stars, the mass of which by the moment of compression exceeds the critical value.
If when the loss of stability within the star there's no unharness of energy sufficient to prevent the compression or explosion, at that the remaining mass when the explosion would recede vital, the central elements of the star collapse and during a short time reach the attractive force radius. No force will stop a star from being any compressed if its radius is reduced (to the Schwarzschild sphere radius). The most feature of the Schwarzschild sphere is that no signals emitted from the surface of the star reaching this sphere are often free. Thus, as a result of attractive force compression of large stars, there seems a locality of reference frame from that no info regarding physical processes occurring within it will leave.
Temporary tunnels?
There are identified difficulties related to heavenly body travel. A variety of theoretical works show the likelihood of the existence of tunnels connecting any remote areas of Metagalactica or varied mini-universes within the massive Universe. A system of 2 tunnels, that provides the movement of matter and radiation in any direction, for associate external observer is going to be terribly just like a double system consisting of a black and white hole.
Through analog of a part, it's potential to pass from one half of our Universe in its different part or indifferent universe. Through the analog of a white hole it's potential to access U.S. The concept of exploitation topological tunnels is employed within the novel by the renowned yank urbanologist K. Sagan "Contact".
Ergosphere
Calculations show that a rotating black hole outside its surface should have an area bounded by the static limit surface, i.e. the ergosphere. The gravitational force from the black hole acting on a stationary body placed in the ergosphere turns into infinity. However, this force is finite. Any particles in the ergosphere will rotate around the black hole. The presence of the ergosphere can lead to a loss of energy of the rotating black hole. This is possible, in particular, if somebody, flying into the ergosphere, breaks up (for example, as a result of an explosion) near the surface of the black hole, into two parts, with one of them continues to fall on the black hole, and the second flies out of the ergosphere. The parameters of the explosion can be such that the energy of the part flying out of the ergosphere is greater than the energy of the former body. Additional energy is drawn from the rotation energy of the black hole. As the moment of its rotation decreases, the surface of the static limit merges with the surface of the black hole and the ergosphere disappears. Rapid rotation of the collapsing body prevents the formation of a black hole due to the forces of rotation. Therefore, the black hole cannot have a moment of rotation greater than some extreme value.
Laplace's hypothesis
The first person to assume the existence of black holes was Simon-Pierre de Laplace, who, studying the theory of gravitation, put forward a hypothesis about the existence of objects moving at a speed exceeding the speed of light. The scientist assumed that there is a body whose speed is so high (about 300,000 km/h) that light cannot be emitted from its surface.
Hawking's work
Stephen Hawking, despite his tough life, darkened by the gift of speech and total immobility, has written several works, as well as tries to clarify the physical basis of the large Bang theory, the popularity of black holes and a big deformation of area and time within them.
One of the foremost attention-grabbing facts advanced by Hawking was that black holes are not totally "black", however, can emit radiation due to quantum effects before their own disappearance or explosion.
Conclusion
You can learn a lot about black holes by studying them closely. There are so many new and unknown things in the abysses of the Universe that I think it will be studied for a long time.
It is certain that with the improvement of technology we will someday be able to know, refute or prove today's assumptions and hypotheses, which people expressed hundreds of years ago.
Rightly said G. Druno: "Mental power will never rest, will never stop at the known truth, but will always go on and on, to the unknown truth.