Simply, black hole is a region of space that has such a large amount of concentrated mass that nothing can escape the lure of the force of gravity, not even light, which is why they are called "black holes". Black Hole (artistic design). To date the best theory to explain this kind of phenomenon is the general theory of relativity, formulated by Albert Einstein. But to better understand what it is a black hole you need to understand some concepts.
According to Einstein's theory, the force of gravity would be a manifestation of deformation in space-time caused by the mass of celestial bodies such as planets or stars. This deformation would be more or less according to the mass or density of the body. Therefore, the greater body mass, the greater the deformation, and in turn, the greater the force of gravity it. Consequently, the greater the escape velocity, minimum force to be employed, so that an object can overcome gravity of this body. For example, for a rocket leaving the Earth's atmosphere into space he needs an escape force of 40,320 km / h. In Jupiter, this force would have to be 214,200 km / h. This very big difference, it is because its mass is much larger than Earth.
|Black Hole (artistic design). Illustration: NASA|
That's what happens in black holes. There is a great concentration of mass at a point so as infinitely small that the density is sufficient to cause such deformation space-time velocity to escape at this location is greater than that of light. So that not even light can escape from a black hole. And since nothing can move faster than the speed of light, nothing can escape a black hole. These such black holes would be stars in their last stage of evolution, when, after consuming all its fuel, the star with mass greater than 3 solar masses, become a supernova with a "lump" in the center. If the mass of the core, which may or may not form, is greater than 2 solar masses it falls on itself, turning into a black hole.
Sometimes it happens star evolve into what we call "binary closed" when two stars are very close and there is transfer of matter from one to another, can make one of them accumulate excess mass causing it to explode in a supernova. In these cases, the more likely it evolves to a neutron star, when electrons and protons merge into neutrons. But it happens that in some systems the mass concentration is very large and there is the formation of a black hole that continues "sucking" the mass of that other bigger star.
By Caroline Faria