Thursday, July 22, 2004

Black holes, boggled minds

Several stories I have seen on the Hawking announcement call black holes "cosmic vacuum cleaners that go around sucking up everything in their path." That's a bit of hyperbole. You would fall toward a black hole just as you fall toward Earth or any other object with gravity.

With black holes, the trick is getting out again.

Getting off the Earth is not easy either. You must move fast enough to overcome Earth's gravity -- the so-called escape velocity. Even harder to escape Jupiter, because the surface gravity is greater.

When the escape velocity of an object equals the speed of light, nothing can get away -- except Hawking's quantum "seepage."

Presumably, most black holes in the universe are the collapsed cores of massive dead stars. With no force strong enough to stop the collapse, the core shrinks to an infinitesimal point. That pinprick of superdense matter, which can weigh more than the entire Solar System, is surrounded by a bubble of space about the size of Rhode Island from which there is no escape -- the black hole.

All things considered, I'd rather visit Rhode Island.