Stephen Hawking, the star that enlightens Contemporary Physics
Prisoner of a deadly disease, Stephen Hawking Einstein
seems to have inherited the aura of fame and reputation of genius. Having taken two years of life, Hawking was plunged into depression. As noted by writer Dennis Overbye, "Hawking was hard not to think of as its own metaphor." Hawking He thought that if a star could collapse to be a singularity, the process should also be possible in the opposite direction. A singularity can be both a beginning and an end. Hawking was able to show something more than this: an infinitely expanding universe, has shown, must have begun at a singularity. But what if the universe does not expand infinitely? What if it contains enough mass to be slowing the explosion and reversed, ending in the fatal implosion called the Big Crunch? Do you also that universe should have begun at a singularity? The answer, said Hawking, was yes. A researcher at Princeton, Jacob Bekenstein, picked up the idea. Bekenstein saw a parallel between black holes and the idea of entropy, the measure of random chaos within a system. The size of the black hole entropy and its quantity could be equivalent. Hawking rejected the analogy. Two Soviet physicist Hawking persuaded to consider the possibility that black holes could, nevertheless emit particles. When Hawking found repeated calculations, "to my surprise and annoyance, that even the non-rotating black holes were, apparently, create and issue regular particles. The particle appears to be rising from the black hole. In which case, in the words of Hawking, "Black holes are not so black." The radiation of a black hole actually comes from the black hole itself but the layer of surrounding space. That energy has to come from the black hole. The black hole shrinks a little and radiate faster. This will not happen in any time soon, the black hole type take about 1067 years to fade away. Even black holes whose mass equals that of the Sun are too large, because the particles would have to exceed the speed of light for miles before returning to the regular universe. But what about black holes exceptionally small? This is another story. Hawking suggests the possibility that when the universe was young and much denser than now create primordial black holes, sandwiches the size of a mountain. These mini black holes, artifacts of creation, they should not take too long to evaporate. Hawking imagines that should be evaporating right now, disappearing in gamma ray bursts. So the idea of Hawking that black holes could not be made smaller was refuted by the discovery of Hawking radiation, which shows that black holes may disappear altogether. Something similar happened to his ideas about the uniqueness of the beginning of time. General relativity is true, requires the existence of singularities, but in point of singularity, where matter is compressed to infinite density, general relativity breaks. Hawking decided that his earlier idea that the universe began with a singularity was wrong. Perhaps the space-time universe began not in any way. The argument amounts to something like this: if we close enough to the beginning of the universe, time does not exist, if the weather does not exist, there is a moment of creation, there is no moment of genesis, there is no time whatsoever. No time, no time. Hawking said that in any case the universe seems to begin and end in a singularity. ( "So in a sense we are still all doomed," writes Hawking.) This proposal "without limits" Hawking compared, typically, the universe and the Earth. Hawking also speculated about baby universes, byproducts of inflationary model of the universe due to Alan Guth, whereby during a fleeting fraction of a second the universe swelled enormously. If this process created small swellings inside the factory of space-time, those small hills and valleys may well grow in parallel universes inflating connected to ours by wormholes, quantum tunneling through space-time. In which case our universe would be one among many. In the documentary directed by Errol Morris Hawking, Hawking's sister, Mary, said: "My father was very good in theological discussions, so all we talked about theology." This seems to be a habit that Hawking has never lost. In his writings Hawking repeated again and ambivalence about the problem, in the words of her sister May, "the existence of God or otherwise. He writes with humor about his experiences in the Vatican, where he attended a conference on cosmology in 1981: "At the end of the conference participants were granted an audience with the pope. Then all, philosophers, scientists and ordinary people, take part in discussions on the question of why we and the universe exist. If we find the answer to this question will be the ultimate triumph of human reason: for then we will know the mind of God. "