Black holes: what do we know about them?B 1783 the English geologist and the astronomer John Michel (1724 - 1793) the first assumed that in the nature there can be so massive stars that even the ray of light is not capable to leave their surface. Stated the same idea in the book “ System of the world “ (1796) French mathematician and astronomer Pierre Simon Laplace.
Black holes - areas of space in which the gravitational attraction is so big that neither substance, nor radiation can leave them. The black hole is separated from other space “ horizon of events “ - a surface on which the second cosmic speed is equal to velocity of light. As in the nature nothing can move with greater speed, no data carrier can leave from - under the horizon of events (often it is called “ surface of a black hole “) .
Therefore the internal part of a black hole is not connected with other Universe prichinno; occurring “ under a surface “ a black hole physical processes cannot influence processes out of it. At the same time, the substance and radiation falling outside on a black hole can freely get through the horizon of events. In other words, the black hole absorbs everything, but lets out nothing; it also became the reason of its such name offered in 1968 by the American physicist John Archibald Wheeler.
The great scientist Albert Einstein in the general theory of relativity proved a possibility of existence of black holes. Stars are an evolving objects, that is they are in continuous change and development. They as people, are born, live, die. And though for all the time of existence of a civilization in the sky did not disappear and any did not appear noticeable to a star eye (except for flashes of supernew and new stars), stars do not remain invariable.
Gradually thermonuclear fuel in them is burned out also by a star “ grows old “. The more the mass of a star, the quicker passes it the course of life, becomes the red giant, and then can turn in the white dwarf and cool down very slowly, or under the influence of a gravitational field to contract to nuclear density, having become a neutron star, or to blow up as supernew, or to become a star - the invisible being under the name “ black hole “.
Existence of these unusual objects follows from the theory of relativity of Einstein with inevitability. Gravity is connected with physical properties of the space. It appears, any body not just exists in space in itself, but changes “ around “ its geometry.
In everyday life we do not notice a space bend as it is necessary to deal with rather small masses. But in space objects can have enormous weight, and, therefore, and a powerful gravitational field and to bend space just as the massive sphere bends the tense loading.
On such surface some easy sphere will come down in the direction to heavy, being as if attracted to it. The theory predicted, and supervision confirmed that beams of stars are bent by the Sun. Astronomers observe it during total solar eclipses. The powerful gravitational field of a massive star so strongly compresses its substance that not only substance, but even the electromagnetic radiation (radio waves) cannot leave a star, and it stops being visible. In total - substance, any kind of radiation - will fail as if in an invisible hole.
Scientists calculated the gravitational radius at which the celestial body can turn into a black hole. For a star like our Sun it makes 3 km. Massive stars can turn into a black hole (more largely than our Sun many times over) at their catastrophic compression - a collapse.
A star - kollapsar, that is the black hole, catches radiation from the outside, but itself does not let out outside of any radiations. The space and time in the field of a kollapsar gain surprising properties: the space is pulled together in a point, actually does not exist, and time also ceases to exist. For the observer who suddenly appeared on “ to edge “ the black hole, will not be either the past, or the present, or the future.]