Time Travel 0898797489, 9780898797480
Time Travel explains science to help you make your fiction plausible. You'll leave for the future from a solid theo
204 24 2MB
English Pages 200 [210] Year 1997
Table of contents :
Cover
Time Travel
Copyright
About the author
Contents
Introduction
The science of time travel
The "laws" of time travel
The difference between science fiction and fantasy
Outline of the book
CHAPTER 1. Time Travel in the Pulps
A brief history of time travel as it was written in the "Golden Age" of science fiction
The pulps and time travel
The special fascination of time-travel stories
Summary
CHAPTER 2. Special Relativity and Time Travel to the Future
An explanation of Einstein's special theory of relativity and why it indicates that time travel may be possible
Einstein's discovery of the relativity of time
The paradox of the twins
Summary
CHAPTER 3. Time Travel to the Past
A look at the scientific groundwork upon which time travel theory is constructed
World-lines, light cones, and closed timelike curves
Causality
Antimatter and time travel
Why Wells's time machine couldn't work
Summary
CHAPTER 4. Hyperspace
The concept of dimension and why we live in a world of at least three spatial dimensions
Folded space-time and wormholes
Space as the fourth dimension
Summary
CHAPTER 5. Time as the Fourth Dimension
A look at how time "moves" and how it can be considered as a spatial dimension
Circular, linear, and helical time
The direction of time
Entropy as an arrow of time
Summary
CHAPTER 6. The Block Universe
Philosophy and science are uneasy neighbors in the block universe
Conservation of mass-energy in time travel
Free will and fatalism
Summary
CHAPTER 7. When General Relativity Made Time Travel Honest
How Godel found what Einstein had overlooked and put forth his own view of time travel
Meeting yourself in the past
Einstein's response to Godel
Summary
CHAPTER 8. Paradoxes: Changing the Past, Causal Loops, and Sex
A overview of time travel paradoxes and why most of them are invalid
The grandfather paradox
The Time Police
Principle of self-consistency
Sexual paradoxes
Summary
CHAPTER 9. Time Machines that Physicists Have Already "Invented"
Theoretical "paper" time machines and how they might work
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
The theory of sending information forward or backward in time
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
Contemporary physicists have a few new ways of looking at time travel
The uncertainty principle
Splitting realities
Multiple time tracks and parallel worlds
Chronology protection
The Back Reaction
Summary
CHAPTER 12. Reading the Physics Literature for Story Ideas
These technical journals are available in academic libraries, or at any college or university with a physics department, and can be scanned for the latest results in time machine physics, and fresh story ideas
Glossary of Selected Terms and Concepts
Bibliography
Index
