Back Cover Blurb
- Collaboration on the First Edition of Spacetime Physics began in the mid-1960s when Edwin Taylor took a junior faculty sabbatical at Princeton University where John Wheeler was a professor. The resulting text emphasized the unity of space- time and those quantities (such as proper time, proper distance, mass) that are invariant, the same for all observers, rather than those quantities (such as space and time separations) that are relative, different for different observers. The text has become a standard for modern physics and relativity courses, as well as introductory physics.
- The Second Edition of Spacetime Physics embodies what the authors have learned during an additional quarter century of teaching and research. They have updated the text to reflect the immense strides in physics during the same period and modernized and increased the number of exercises, for which the First Edition was famous. Enrichment boxes provide expanded coverage of intriguing topics. Sample problems encourage students to exercise their newfound power. An enlarged final chapter on general relativity includes new material on gravity waves, black holes, and cosmology.
- The Second Edition of Spacetime Physics provides a new generation of students with a deep and simple overview of the principles of relativity
- Relativity describes Nature from quark to cosmos. Relativity empowers its user to ponder deeply, to analyze widely, to predict accurately. It is a theory of fantastic innocence, simplicity, and power.
- Yet "relativity theory" is a misleading term; a term Albert Einstein avoided for years. True, he recognized and revealed to the world that the time between two events is typically different as recorded by Earth observer or spaceship commander Time between events is relative. Relative too is the distance between events. Yet behind these differences Einstein discerned unity; concepts and quantities on which everyone in the universe agrees. What concepts and quantities?
- Events. An explosion is an explosion. A birth is a birth. Whether it is the birth of a star or your own birth, everyone agrees that it happens.
- Wristwatch time. Carry a wristwatch directly from one event to a second event, so that both take place at the wristwatch. Or lay a rod between two events that occur at the same time. Everyone, correctly predicts the wristwatch reading and this rod length.
- The path connecting events. Were you, there, at the first event? Yes. And at the second? Yes. And the last? Yes. Does everyone in the universe agree that you were present at every event in this string? Yes. Does everyone agree on the advance of your wristwatch rime from event to event along this entire string of events? Yes!
- Conservation laws. Everyone agrees that momentum is conserved in a collision of particles. It is also conserved when particles are created, transformed, or annihilated in that collision. Energy, too, is conserved in the same collision, everyone agrees.
- Agreements of these four kinds bear witness to a powerful and simple unity, the unity of space and time: spacetime! Special relativity explores the unity of spacetime. General relativity recognizes that spacetime is not just a passive stage on which events occur; spacetime is an actor that takes part in physical events. All of relativity comes in a single simple sentence: Spacetime grips mass, telling it how to move: and mass grips spacetime, telling it how to curve.
- SPACETIME: OVERVIEW: The great unity is spacetime; its measure, the spacetime interval, is the same for all observers.
1.1 Parable of the Surveyors 1
1.2 Surveying Spacetime 5
1.3 Events and Intervals Alone! 9
1.4 Same Unit for Space and Time: Meter, Second, Minute, or Year 11
1.5 Unity of Spacetime 15
- FLOATING FREE: Jump off the roof: On the way down — in free float — we have an (almost!) perfect setting for conducting experiments.
2.1 Floating to the Moon 25
2.2 The Inertial (Free-Float) Frame 26
2.3 Local Character of Free-Float Frame 30
2.4 Regions of Spacetime 34
2.5 Test Particle 36
2.6 Locating Events With a Latticework of Clocks 37
2.7 Observer 39
2.8 Measuring Particle Speed 40
2.9 Rocket Frame 41
- SAME LAWS FOR ALL Without looking out of the window, we cannot tell which free-float frame we are in.
3.1The Principle of Relativity 53LORENTZ TRANSFORMATION
3.2 What Is NOT the Same in Different Frames 56
3.3 What IS the Some in Different Frames 60
3.4 Relativity of Simultaneity 62
3.5 Lorentz Contraction of Length 63
3.6 Invariance of Transverse Dimension 65
3.7 Invariance of the Interval Proved 67
3.8 Invariance of the Interval for ALL Free-Float Frames 71
L.1 Lorentz Transformation; Useful or Not? 95
L.2 Faster Than Light? 96
L.3 First Steps 99
L.4 Form of the Lorentz Transformation 100
L.5 Completing the Derivation 101
L.6 Inverse Lorentz Transformation 102
L.7 Addition of Velocities 103
L.8 Summary 111
- TRIP TO CANOPUS: Travel quickly to a distant star and return, to find we have traveled into the future.
4.1 Invitation to Canopus 121
4.2 Stripped-Down Free-Float Frame 121
4.3 Faster Than Light? 122
4.4 All of Space is Ours! 123
4.5 Flight Plan 124
4.6 Twin Paradox 125
4.7 Lorentz Contraction 126
4.8 Time Traveler1 127
4.9 Relativity of Simultaneity 128
4.10 Experimental Evidence 131
- TREKKING THROUGH SPACETIME: Move or stand still; in either case we soar through spacetime.
5.1 Time? No. Spacetime Map? Yes. 137
5.2 Same Events,-Different Free-Float Frames 139
5.3 Invariant Hyperbola 143
5.4 Worldline 143
5.5 Length Along a Path 147
5.6 Wristwatch Time Along a Worldline 148
5.7 Kinked Worldline 152
5.8 Stretch Factor 155
5.9 Touring Spacetime Without a Reference Frame 160
5.10 Summary 162
- REGIONS OF SPACETIME: The speed of light is a mighty harrier that preserves cause and effect.
- 6.1 Light Speed: Limit on Causality2 171
6.2 Relation Between Events: Timelike, Spacelike, or Lightlike 172
6.3 Light Cone: Partition in Spacetime 177
- MOMENERGY: A second great unity is momentum-energy (momenergy); its measure, mass, is the same for all observers.
7.1 Momenergy: Total Conserved in a Collision 189
7.2 Momenergy Arrow 191
7.3 Momenergy Components and Magnitude 195
7.4 Momentum: "Space Part" of Momenergy 199
7.5 Energy: "Time Part" of Momenergy 201
7.6 Conservation of Momenergy and its Consequences 207
7.7 Summary 211
- COLLIDE. CREATE. ANNIHILATE: Convert mass to energy and energy to mass.
8.1 The System 221
8.2 Three Modest Experiments 222
8.3 Mass of a System of Particles 224
8.4 Energy Without Mass: Photon 228
8.5 Photon Used to Create Mass 233
8.6 Material Particle Used to Create Mass 234
8.7 Converting Mass to Usable Energy: Fission, Fusion, Annihilation 237
8.8 Summary 244
Dialog: Use and Abuse of the Concept of Mass 246
- GRAVITY; CURVED SPACETIME IN ACTION: Gravity is not a force reaching across space but a distortion — curvature! — of spacetime experienced right where you are.
- 9.1 Gravity in Brief 275
9.2 Galileo, Newton, and Einstein 275
9.3 Local Moving Orders for Mass 277
9.4 Spacetime Curvature 280
9.5 Parable of the Two Travelers 281
9.6 Gravitation as Curvature of Spacetime 284
9.7 Gravity Waves 288
9.8 Black Hole 292
9.9 The Cosmos 296
W. H. Freeman & Co. NY, 1993; Third Printing 1996
Text Colour Conventions (see disclaimer)
- Blue: Text by me; © Theo Todman, 2019
- Mauve: Text by correspondent(s) or other author(s); © the author(s)