Nothing, not even light, can ever escape from a black hole. These drainpipes of the universe contain matter to heavy and no highly concentrated that gravitational attraction overwhelms all other forces. Yet astronomers believe that today's universe exploded out of a gargantuan black hole in a "high bang" billions of years ago, and that it may collapse back into such a black hold again.
English astrophysicist Steven Hawking, who spent the last two weeks at Harvard lecturing and meeting with researchers, has devoted most of his life to studying these gashes in the fabric of space and time. I've always wanted to understand why the world is what it is and how it works," says Hawking, now a successor to Sir Isaac Newton as Lucastan Professor of Mathematics at Cambridge University. Since, according to Hawking, "we already know completely the laws that govern normal matter," his goal is to extend such knowledge to extreme conditions. Nothing is more extreme than a black hole.
Most of a Hawking's research to date has focused on relativity, the theory developed by Albert Einstem to show that the laws of physics are the same everywhere and that apparent differences are caused only by the relative motions of various observers or by the forces acting on them. Hawking's work has so transformed our conceptions of black holes and gravitation that many physicists consider him the most important relatively theorist since Einstein.
I don't know anybody who's contributed more to the study of black holes," said John Archibald Wheeler, inventor of the term "black hold" and a professor of physics at the University of Texas at Austin
For instance, until recently astronomers beleived that black holes were cold and didn't emit radiation This seemed logical since the gravitational of a black hole would be strong enough to keep any radiation from escaping But Steven Hawking, applying the theory of quantum mechanics to black holes, proved that they do give off radiation, in other words, black holes are sort of gray.
Amazingly, Hawking has done his ground-breaking research despite a tremendous handicap. For the last 20 years the physicist has suffered from Lou Gehrig's disease, a terminal degenerative illness of the nerves and muscles. Now, at 40, Hawking remains confined to an electrically controlled wheelchair and has difficulty holding his neck up when he speaks. Even then his voice barely escapes--it comes out sometimes as a guttural moan--and Hawking generally travels with an interpreter.
Despite his illness, Hawking impresses all who meet him with his cheerfulness and almost childlike joy, and is always smiling and making quips. Wheeler, who has known Hawking for many years, said that despite his disease. "He's still in a way the same Steven. He's got the light of life--the hope, the liveliness, the sparkle--in his eyes."
Hawking's prodigious research achievements and unceasing optimism in the face of his debilitating disease have been called a model for handicapped people. Many of his colleagues suggest that, in an odd twist of fate, Hawking's disease may have helped his work by forcing him to focus exclusively on the faraway physical world.
"Steven could have been a great physical if he hadn't been ill, but he might have chosen not to be," says William H. Press, professor of Astronomy and of Physics, and Malcolm J. Perry, a former graduate student of Hawking's at Cambridge who now teaches physics at Princeton, explains, "Most of us are subject to an infinite number of distributions. His illness has protected him from these."
But, as Arthur M. Jaffe, Harvard professor of Mathematical Physics and Hawking's host while he was here, puts it: "He can devote complete attention to his work. But it's a terrible price to pay."
The physicist, however, is certainly not a pure thinking-machine. Married for 17 years, he and his wife Jane have three children--two sons and one daughter. According to Hawking's former student Perry. "Everybody gets to know his family" because he's so open and friendly.
Asked whether he would like his children to pursue science. Hawking replies. "It's very hard for children to follow in their father's footsteps because they're likely to be overshadowed at the start. But my eldest son [Robert, now 12 years old] is very interested in mathematics and physics . . . ."
Hawking's father was a scientist too, a biologist who researched tropical diseases. Although his father encouraged him to pursue biology and medicine. Hawking avoided these fields because he thought they were too impercise. If he had been able to predict the explosion in molecular biology, however, the physicist says he might have chosen that route since it is "one of the most exciting fields in science today."
As a child, Hawking took apart clocks and motors to see if he could understand how they worked Today, using mathematics instead of screwdrivers, he disassembles parts of the faraway universe that he can't even touch and tries to picture their mechanics.
According to the uncertainty principle of quantum mechanics, it's impossible to determine both the location of a small practice and its velocity at the same time. This means that a particle and its anti-particle--its mirror image of opposite--can appear and disappear so long as they don't get too far apart before wiping each other out.
This random creation and destruction of matter happens everywhere and usually has no effect. But when such particles are created near a black hole. Hawking had shown, the black hole's gravitational field sometimes drags in only one of the paid while the other flies off into free space. These escaped particles give off the radiation that seems to come from inside the black hole.
More than 500 listeners recently jammed Science Center C to listen to each of Hawking's three lectures on gravitational collapse. Hawking explained that gravity can force matter to collapse into black holes and that time seems to end for particles trapped inside because outside observer can no longer determine what happens to them. Saying this theory has provoked "the greatest crsis physics of all time added. "It seems to indicate that time itself has a beginning and in end".
Black holes have attracted a lot of attention in the past few years, spawning pinball games, adventure movies, and dozens of sci-fi novels. Hawking says he's very glad to see all the popular interest, but he's not always so pleased with the form it takes. For instance. Walt Disney invited him to be a consultant for its film. "The Black Hole." Although he turned them down, he did accept an invitation to the movie premier. "It was an awful film," he says.
Part of the popular fascination with black holes comes from their origins. When stars use up all of their nuclear fuel and become too cold to produce the pressure needed to withstand the force of gravity, they collapse, forming black holes.
But Hawking's scenario for doamsday does not include the earth vanishing into a black hole that was once the sun Only stars about and a half times as big as our sum have enough mass to form one.
Instead, Hawking thinks nuclear was is "by far our most dangerous worry." He endorses the new disarmament movements in Europe and hopes they'll at least succeed in removing nuclear weapons from Britain and the continent "I thin that we should all disarm now and not wait for the other side to do so first. The survival of the human race is much more important than the difference between capitalism and communism."
But in the face of nuclear war. Hawking is far from depressed. He retains his underlying optimism no matter what prospects he's discussing. If we can survive the next 100 years, he says, then the human race will be able to improve itself through genetic engineering and perhaps colonize the entire galaxy. "But on the other hand," he says, "maybe that is a depressing prospect."
Hawking and many other physicists are now seeking a theory to explain all the physical qualities of the universe by a single basic force. Finding such a force would not mean that scientists could predict the weather or the color of babies' hair, but it would prove that the universe is orderly at every level.
Hawking believes that we could find such a theory within 20 years. But other people have also been convinced that they've found an all-encompassing model for the universe, he says, and they have been proved wrong. The new theory might also be wrong, he says, but at least it would be closer to the truth. "There may be discoveries that will modify our ideas, but I don't think they'll ever change them completely."