Chandrasekhar limit is the limit mass of degenerate star that will confine itself to its further evolution. Chandrasekhar limit is 1.4 solar masses. Each star must at least once in nuclear reactions in its center spend the available nuclear stocks. The more massive star it is before will happen the disappearance of fuel. This is because more massive stars should be hotter to hold by its higher pressure the balance of own gravity, which is trying to collapse. When the star runs out of fuel, begins to cool and shrink.
If the mass is much smaller than the Chandrasekhar limit star will be clamped to the size of a white dwarf. If the cold star has a mass of approximately 1 to 1,5 mass of the Sun, it will compress to the radius of about 10 kilometers, with density of several billion tons per cubic centimeter. Such a star is made up exclusively of protons and neutrons and is therefore called a neutron star. A third possibility is that the cold star has a mass greater than Chandrasekhar limit, and then nothing can stop the process of tightening the star in one point - a black hole.
Scientist Chandrasekhar calculated that a star with a mass greater than about 1,5 mass of our Sun, would not be able to hold up under pressure from its own gravity. Because of that this mass is called the Chandrasekhar limit. It is interesting that our sun would be compacted to a diameter of 3 000 km to become a black hole, and that the Earth would be compacted to a diameter of 1 cm to become a black hole. A black hole is defined as a series of events which is not possible to escape to the great distance. Means that the boundary of a black hole, event horizon, create rays of light that failed to move away from the black hole. Instead, they remain there forever, hovering on the borders of the black hole.