The problem arose when too much mass was concentrated in a very small area, as occurs when agiant star exhausts its fuel and begins to collapse. According to Schwarzschild39;s calculations, in such a case, space-time would not simply bend; it would tear apart. The star would go on compressing and its density would increase till the force of gravity became so powerful that space would become infinitely curved, closing in on itself. The result would be an inescapable abyss permanently cut off from the rest of the universe.