The Nature of Space and Time

Portada
Princeton University Press, 1996 - 141 pàgines

Einstein said that the most incomprehensible thing about the universe is that it is comprehensible. But was he right? Can the quantum theory of fields and Einstein's general theory of relativity, the two most accurate and successful theories in all of physics, be united in a single quantum theory of gravity? Can quantum and cosmos ever be combined? On this issue, two of the world's most famous physicists--Stephen Hawking (A Brief History of Time) and Roger Penrose (The Emperor's New Mind and Shadows of the Mind)--disagree. Here they explain their positions in a work based on six lectures with a final debate, all originally presented at the Isaac Newton Institute for Mathematical Sciences at the University of Cambridge.


How could quantum gravity, a theory that could explain the earlier moments of the big bang and the physics of the enigmatic objects known as black holes, be constructed? Why does our patch of the universe look just as Einstein predicted, with no hint of quantum effects in sight? What strange quantum processes can cause black holes to evaporate, and what happens to all the information that they swallow? Why does time go forward, not backward?


In this book, the two opponents touch on all these questions. Penrose, like Einstein, refuses to believe that quantum mechanics is a final theory. Hawking thinks otherwise, and argues that general relativity simply cannot account for how the universe began. Only a quantum theory of gravity, coupled with the no-boundary hypothesis, can ever hope to explain adequately what little we can observe about our universe. Penrose, playing the realist to Hawking's positivist, thinks that the universe is unbounded and will expand forever. The universe can be understood, he argues, in terms of the geometry of light cones, the compression and distortion of spacetime, and by the use of twistor theory. With the final debate, the reader will come to realize how much Hawking and Penrose diverge in their opinions of the ultimate quest to combine quantum mechanics and relativity, and how differently they have tried to comprehend the incomprehensible.


Altres edicions - Mostra-ho tot

Sobre l'autor (1996)

Stephen William Hawking was born on January 8, 1942 in Oxford, England. As a student at Oxford University, Hawking studied Physics, and after three years was awarded a first class honors degree in Natural Science. After gaining a Ph.D. from Cambridge, Hawking became a Research Fellow, and later on a Professional Fellow at Gonville and Caius College. Widely regarded as one of the greatest theoretical physicists since Einstein, Hawking has held the post as Lucasian Professor of Mathematics at the University of Cambridge since 1979. Most famous for his research on black holes, he has written the books A Brief History of Time and Black Holes and Baby Universes, a collection of essays published in 1993. He also authored the books On the Shoulders of Giants, A Briefer History of Time, The Universe in a Nutshell, and The Grand Design. Hawking is also the author of numerous articles for scientific papers, has 12 honorary degrees and is a Fellow of The Royal Society and a Member of the U.S. National Academy of Sciences. Hawking was diagnosed with Lou Gehrig's disease in his early 20s and is now confined to a wheelchair. He uses a computer device to help him speak. Hawking holds a professorship at the University of Oxford. In 2015 Hawking's book A Brief History of Time, which he completed in 1984, became listed on the New York Times bestseller list.

Born in England, the son of a geneticist, Roger Penrose received a Ph.D. in 1957 from Cambridge University. Penrose then became a professor of applied mathematics at Birkbeck College in 1966 and a Rouse Ball Professor of Mathematics at Oxford University in 1973. Penrose, a mathematician and theoretical physicist, has done much to elucidate the fundamental properties of black holes. With Stephen Hawking, Penrose proved a theorem of Albert Einstein's general relativity, asserting that at the center of a black hole there must evolve a "space-time singularity" of zero volume and infinite density, in which the current laws of physics do not apply. He also proposed the hypothesis of "cosmic censorship," which claims that such singularities must possess an event horizon. In 1969 Penrose described a process for the extraction of energy from a black hole, as well as how rotational energy of the black hole is transferred to a particle outside the hole. In addition, Penrose has done much to develop the mathematics needed to unite general relativity, which deals with the gravitational interactions of matter, and quantum mechanics, which describes all other interactions.

Informació bibliogràfica