Black Holes, Invisible Bodies of Intense Gravity

A black hole is an (almost invisible) body in space, most likely created by a collapsed star super red giant, which is so dense that neither matter nor light can escape its attraction.
Inside a star, there is a constant struggle between the pressure of active and passive gravity pressure from heat. If you were to throw an unopened can of soda in a fire, the drink would remove from the heat and explode. This is the same principle at work when a star is burning, its heat generated great pressure to the outside, but this constant explosion is by gravity, is just as strong, so that a star maintains its shape and size.
When a star is approaching the end of his life it slowly cools and the outside pressure is growing weaker and weaker as the temperature of the star drops. The passive pressure of the heat is almost over, the pressure from inside gravity and still depends on the size of the star. It is the theory that if a star is about ten times as large as our sun is approaching the end of his life, as it shrinks its own gravity pulls it slowly, but as soon as they are more and more dense the gravity is stronger.
The focus is so intense that not even light can escape. Have you ever seen a swirling water flow, then you have a pretty good idea what happened, like a black hole draws in. As things matter and light approach near a black hole slowly, they are in. If they do not tip, especially for the spatial anomaly then they are in a violent and unstable orbit around the black hole until the orbit decays and it is sucked by the immense gravity.
The size of the black hole is determined by the mass of collapsed stars. The critical radius of a non-rotating black hole is known as Schwarzschild radius, named after the German astronomer Karl Schwarzschild (1873-1916) studied the problem in 1916 on the basis of Einstein's theory of general relativity theory. Following the general theory of relativity, the gravity of a black hole bends space and time to such an extent in which they divided into a dimensionless body of infinite density.
The border around the collapsed star with this radius is known as "event horizon". Everything, whether it be light or matter of such border, forever lost within the black hole with no chance of escape. What happens beyond the event horizon, no one can say, because all laws of physics break and no longer apply. There are many theories, but little evidence to support them.
Black holes can not be seen, because they do not emit any electromagnetic radiation *. But they can be detected because of their impact on the surrounding stars.
In a binary star system, Cygnus X-1, (where the primary is a normal star of about 30 solar masses) by Doppler shifts from the system, it is assumed that there is a crew of about 10 to 15 solar masses orbiting the primary . There are X-ray emissions from the system, usually in connection with an "accretion disk" (a hot, dense disk of gas primarily star spiral down into the compact object orbiting the primary). There is evidence that the X-rays are emitted by the orbiting companion. Due to the mass of the companion object It is believed that this is a black hole.
The evidence of black holes is mounting, and it is now of the opinion that most galaxies a large enough size and our own may also have a black hole in its center.
* It is now known that black holes radiate the so-called Hawking radiation, this is a complex process, but also for those who are interested in a brief statement. Virtual particles are constantly generated couples near the horizon of the black hole as they are everywhere. Normally, they are a particle-antiparticle pair and they quickly destroy each other. But near the horizon of a black hole, it is possible that a decline before the destruction can happen, in which case the other escapes, as Hawking