What is a black hole?.

General theory of relativity appeared in 1916 shortly after Carl. Schwarzschild (karl schwarzchild) to calculate the Einstein equations to describe the space-time as a very useful solution. .The solution as a possible shape of space and time, can be used to describe a spherically symmetric, uncharged, non-spin objects (which may also be used for approximate description of the earth and the sun and other such objects spin slowly) than the gravitational .field. .The principle and when you want to study on the surface rather than Newtonian gravity as the Earth as a particle. .This solution is like a "metric." .Pythagorean formula for it and will be summarized to give the plane the same length of the line, this "metric" can be used as access to space-time curve segment "length" formula. .Objects along the time ("time axis") movement if the length of the curve this formula to precisely the time experienced by moving objects. .The final form depends on the formula used to describe the things you choose a coordinate system. .Formula can be deformed due to the different coordinates, but the physical quantities such as the curved space-time is not affected. .Schwarzschild coordinate terms expressed by its "metric" concept: at a distance far away objects, similar to that of a time with an additional axis of spherical coordinates t, r coordinates for where the other .coordinate radius of the ball; and further afield, it only gives the distance between objects. .However, when the spherical coordinate very young, the solution became surprised again. .In the center of r = 0 there is a "singularity", where the curved space-time is infinite; the region around that point, the ball actually become negative direction coordinates of the time (not space) direction. .Any thing in this range, including light, would for the tidal forces tear to pieces and forced hurtled singularity. .This region is the disappearance of a Schwarzschild coordinate surface and the universe, separated from the rest. .Of course there is no problem bending time and space (the sphere radius is called the Schwarzschild radius, the later will find that the Schwarzschild coordinate has not disappeared. It is an artificial coordinate, this seems like the definition of the longitude of the North Pole .encountered problems. Schwarzschild radius of the physical meaning of the coordinates of the problem is not there, but in their time in the direction into the direction of this fact.) .At that time people did not have to worry about, because all the known density of objects within reach to make this area expanded to the extent of outside objects, that is, for all known cases, the Schwarzschild solution is not the strange part .applicable. .Arthur. Stanley. Eddington (arthur stanley eddington) had considered after the collapse of a dying star may reach this density, but from the aesthetic point of view is not pleasant to be abandoned, and there should be a new man .added in theory. .1939 Owen Heimer (oppenheimer) and Schneider (snyder) made the final seriously several times larger than the solar mass stars in their final declaration to this state may collapse. .Once the collapse of a star sphere over the disappearance of the Schwarzschild coordinates (called non-live, the Schwarzschild radius of spin objects or "Horizon"), it will inevitably continue to collapse down. .You can not stop with the wheel of time, as it has been the collapse to the singularity. .There is no access to that area of things can be spared, at least in this simple example is the case. .Horizon is a turning point of no return. .John in 1971. Archie Baird. Wheeler (john archibald wheeler) named such things as "black hole" because light can not escape from. .Based on much evidence, many astronomers believe they may be black hole candidate objects (the evidence is: they can from the great quality of the interaction of other objects to get; and sometimes they send x-rays, which is considered is .fall into one of the substances emitted). .But we here about the nature of black holes is purely theoretical, they are based on general relativity - a currently prove to be the correct theory. .<B </ p>.