Black holes are objects of the universe that attract the interest of many astronomers. Black holes, space objects, the existence of which is predicted by the general theory of relativity. They are formed during unlimited gravitational collapse of massive cosmic bodies (in particular, stars with masses of 40-60 M?). Gravity collapse – catastrophically fast compression of a star under the influence of gravitational forces (gravity).
The external structure of the black hole
A black hole has an external gravitational field, the properties of which are determined by mass, angular momentum and, possibly, electric charge if the collapsing star was electrically charged. At large distances, the black hole field practically does not differ from the gravitational fields of ordinary stars, and the motion of other bodies interacting with the black hole at a large distance obeys the laws of Newtonian mechanics. The gravitational field is so strong that it absolutely cannot emit light, so they appear black.
Catastrophic gravity by compression (collapse) can end, in particular, the evolution of stars whose mass at the time of compression exceeds a critical value. The critical mass value is not precisely determined and, depending on the accepted equation of state of the substance, varies from 1.5M? up to 3M? (where M? is the mass of the Sun).
If, after loss of stability, the star does not release enough energy to stop compression or to explode, in which the mass remaining after the explosion would become less critical, then the central parts of the star collapse and in a short time reach the gravitational radius rg. No force can prevent further compression of the star if its radius decreases to rg (to the radius of the Schwarzschild sphere). The main property of the Schwarzschild sphere is that no signals emitted from the surface of a star reaching this sphere can go outside. Thus, as a result of the gravitational compression of massive stars, a region of space-time appears, from which no information about the physical processes occurring inside it can come out.
Known difficulties associated with interstellar flights. A number of theoretical works have shown the possibility of the existence of tunnels connecting any remote areas of the Metagalaxy or various mini-universes in the Big Universe. A system of two tunnels, providing the movement of matter and radiation in any direction, for an external observer will be very similar to a binary system consisting of a black and white hole.
Through the analogue of a black hole, passage from one part of our Universe to another part of it or to another universe is possible. Through the analogue of a white hole, access to us is possible. The idea of using topological tunnels was used in the novel “Contact” by the famous American astrophysicist K. Sagan.
As calculations show, for a rotating black hole outside its surface there should be a region bounded by the surface of the static limit, that is, the ergosphere. The force of attraction from the side of the black hole, acting on a motionless body placed in the ergosphere, turns into infinity. However, this force is finite. Any particles trapped in the ergosphere will rotate around the black hole. The presence of the ergosphere can lead to the loss of energy of a rotating black hole. This is possible, in particular, in the event that a certain body, flying into the ergosphere, breaks up (for example, as a result of an explosion) near the surface of a black hole into two parts, one of which continues to fall onto the black hole, and the second takes off from the ergosphere . Explosion parameters can be such that the energy of the part emitted from the ergosphere is greater than the energy of the former body. Additional energy is derived from the energy of rotation of the black hole. With a decrease in the moment of its rotation, the surface of the static limit merges with the surface of the black hole and the ergosphere disappears. The rapid rotation of a collapsing body prevents the formation of a black hole due to the action of rotation forces. Therefore, a black hole cannot have a moment of rotation greater than some extreme value.