The Nature Of Space And Time PDF
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 physics ideas, 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. They explain their positions in 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 be constructed, a theory that could explain the earlier moments of the big bang and the physics of the enigmatic objects known as black holes? 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 they swallow? Why does the 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 cannot account for how the universe began. Only a quantum theory of gravity, coupled with the no-boundary hypothesis, can 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. He argues that the universe can be understood 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 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.
In a new afterword, the authors outline how recent developments have caused their positions to diverge on several key issues, including the spatial geometry of the universe, inflationary versus cyclic theories of the cosmos, and the black-hole information-loss paradox. Though much progress has been made, Hawking and Penrose stress that physicists still have much further to go in their quest for a quantum theory of gravity.
The Nature Of Space And Time Free PDF Download
Author(s): Stephen Hawking, Roger Penrose
Series: Princeton Science Library
Publisher: Princeton University Press, Year: 2010