## Three Roads To Quantum Gravity"It would be hard to imagine a better guide to this difficult subject."--Scientific AmericanIn Three Roads to Quantum Gravity, Lee Smolin provides an accessible overview of the attempts to build a final "theory of everything." He explains in simple terms what scientists are talking about when they say the world is made from exotic entities such as loops, strings, and black holes and tells the fascinating stories behind these discoveries: the rivalries, epiphanies, and intrigues he witnessed firsthand. "A mix of science, philosophy and science fiction, [this] is at once entertaining, thought-provoking, fabulously ambitious and fabulously speculative." -The New York Times "Provocative, original, and unsettling." -The New York Review of Books "An excellent writer, a creative thinker."-Nature |

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#### LibraryThing Review

User Review - pbenson92025 - LibraryThingI liked parts of this book, as it introduced some new ideas that I had not been exposed to. On the other hand, I miust not have been paying attention because he lost me at several crucial points and ... Read full review

#### LibraryThing Review

User Review - sthitha_pragjna - LibraryThingLee Smolin is one of those physicists who can explain in lucid prose the motivation of his research. Having pioneered loop quantum gravity, he has written a book which is laid out logically and ... Read full review

### Contents

THERE IS NOTHING OUTSIDE THE UNIVERSE | |

IN THE FUTURE WE SHALL KNOW MORE | |

MANY OBSERVERS NOT MANY WORLDS | |

THE UNIVERSE IS MADE OF PROCESSES NOT THINGS | |

WHAT WE HAVE LEARNED | |

BLACK HOLES AND HIDDEN REGIONS | |

AREA AND INFORMATION | |

HOW TO COUNT SPACE | |

KNOTS LINKS AND KINKS | |

THE SOUND OF SPACE IS ASTRING | |

THE PRESENT FRONTIERS | |

THE HOLOGRAPHIC PRINCIPLE | |

HOW TO WEAVE A STRING | |

WHAT CHOOSES THE LAWS OF NATURE? | |

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### Common terms and phrases

accelerating observer amount of information answer approach to quantum Ashtekar atomic structure background independent basic Bekenstein bound called Carlo Rovelli causal structure CHAPTER classical cosmological constant describe dimensions discrete duality Einstein Einstein’s theory electrons elementary particles energy entropy equations evolving existence experience field lines Figure finite formulation fundamental geometry of space gravitons happens hidden region holographic principle horizon idea infinite number interact invented kind lattice laws of thermodynamics light cone look loop quantum gravity Louis Crane mass mathematical measure motion photons physicists physics picture Planck length Planck scale Planck units predictions problem processes quantum cosmology quantum geometry quantum theory quarks questions radiation relational relationships result Screen seems Smolin solutions spacetime speed of light spin network story string theory structure of space superconductor superposition tell temperature theorists theory and loop theory of gravity things threedimensional uncertainty principle understand universe versions