BLACK holes really do imprison matter and light, and sap energy from light that narrowly escapes their grip. Until now, these were only predictions of Einstein’s theory of gravity. But astronomers peering at suspected black holes have at last found compelling evidence that this does actually happen.
Black hole theory says that if a very large star explodes at the end of its life and leaves behind a core weighing more than about three times the mass of the Sun, the core will collapse to a point under its own gravitational pull. So strong would be the gravity of the…
