Time travel : a writers guide to the real science of plausible time travel Cover Contents Preface Acknowledgments Introduction The laws of time travel Outline of the book CHAPTER 1 Time Travel in the Pulps The pulps and time travel The special fascination of time travel stories Summary CHAPTER 2 Special Relativity and Time Travel to the Future Einsteins discovery of the relativity of time The paradox of the twins Summary CHAPTER 3 Time Travel to the Past World lines light cones and closed timelike curves Causality Antimatter and time travel Why Wellss time machine couldnt work Summary CHAPTER 4 Hyperspace Folded space time and wormholes Space as the fourth dimension Summary CHAPTER 5 Time as the Fourth Dimension Circular linear and helical time The direction of time Entropy as an arrow of time Summary CHAPTER 6 The Block Universe Conservation of mass energy in time travel Free will and fatalism Summary CHAPTER 7 When General Relativity Made Time Travel Honest Meeting yourself in the past Einsteins response to Gödel Summary CHAPTER 8 Paradoxes: Changing the Past Causal Loops and Sex The grandfather paradox The uncertainty principle Splitting realities Chronology protection The Back Reaction Multiple time tracks and parallel worlds Summary CHAPTER 12 Reading the Physics Literature for Story Ideas Glossary of Selected Terms and Concepts A B C D E F G H I K L M N O P Q R S T U W Bibliography Index A B C D E F G H J K L M N P Q R S T U V W Z The Time Police Principle of self consistency Sexual paradoxes Summary CHAPTER 9 Time Machines that Physicists Have Already Invented Rotating cylinders Wormholes Exotic matter energy conditions and gravity time dilation Cauchy and chronology horizons Cosmic strings Summary CHAPTER 10 Faster Than Light (FTL) Into the Past Tachyons and special relativity The reinterpretation principle and antitelephones The FTL signed message puzzle The space time geometry of FTL Summary CHAPTER 11 Quantum Gravity Splitting Universes and Time Machines