Pile enough matter into a small enough volume and its gravitational pull will grow so strong that nothing can escape from it. That includes light, which travels at the absolute cosmic speed limit of 186,000 miles per second. In a stroke of descriptive genius, physicist John Wheeler named these objects “black holes.” The radius of a black hole is called the event horizon because it marks the edge beyond which light cannot escape, so any event taking place inside the event horizon can never be glimpsed from outside—in effect, the inside of the black hole is cut off from our universe. It has even been speculated that black holes could be pathways into other universes. Gravity is so strong at the center of a black hole, that even Einstein’s gravitational laws must break down. The theory that governs the incredibly dense matter and strong gravitational fields at the center of a black hole is not yet known.”
CAN ANYTHING ESCAPE FROM A BLACK HOLE?
Black holes are usually thought of as objects with such strong gravity that nothing, not even light, can escape from them. However, Stephen Hawking has shown that black holes can radiate energy. The reason goes back to quantum mechanics and the uncertainty principle. For very brief periods of time, matter or energy can be created from “empty” space because no such thing as truly empty space exists. Hawking realized that if a particle/anti-particle pair came into existence near the event horizon of a black hole, one might fall into the hole before annihilating its anti-particle. The other particle could then escape the gravitational clutches of the black hole, appearing to an outside observer as radiation.