Wizards, Aliens, and Starships

Co-Winner of the 2015 AIP Science Writing Award for Books, American Institute of Physics One of Physics World's Top Ten Books of the Year for 2014 One of The Guardian's Best Popular Physical Science Books of 2014, chosen by GrrlScientist "Whether as a text for a course or as a vehicle for self-study, this book makes for interesting, educational and thought-provoking reading."--Mark Hunacek, MAA Reviews "Adler does a grand job of showing just how powerful even basic maths and physics can be. If you're a budding back-of-the-envelope boffin not afraid of a bit of algebra, you'll love this book."--Robert Matthews, BBC Focus Magazine "I can't work out whether I love or hate this book. I love it because its analysis of the physics behind numerous accounts of magic and space exploration in fantasy and science fiction writing is fascinating. I hate it because it reveals why I will never be able to realise my dream of saying 'Beam me up, Scotty' before being teleported; or so Charles Adler has convinced me... The physics is well explained and Adler offers entertaining examples."--Noel-Ann Bradshaw, Times Higher Education "Wizards, Aliens, and Starships is a great book by itself or as a starting point for exploring the physics of space exploration as well as the classics in science fiction."--Robert Schaefer, New York Journal of Books "For those who want to learn the hard facts about the realities of space travel or the chances for alien life, and as an engaging supplemental text for physics and astronomy courses, Wizards, Aliens, and Starships would be an admirable choice."--Sidney Perkowitz, Scientists' Bookshelf "[A] rewarding and thought-provoking read."--Paul Sutherland, BBC Sky at Night "[T]his book offers a lot, not only to SF authors but to any of you who want to see the real science in operation because this supplies most of the answers you need. Make sure your copy gets a serious read and well-thumbed."--G.F. Willmetts, SFCrowsnest "This book will speak to anyone wanting to know about the correct--and incorrect--science of science fiction and fantasy."--Lunar and Planetary Information Bulletin "[T]his is an interesting, well-written book, and Adler has put a lot of work into it. It should be invaluable for anyone wanting to write really accurate science fiction."--Popular Science "There is much ... in this book to interest readers interested in astronomy and astronautics and I think it will be likely to appeal to physics students."--John Harney, Magonia "Charles L. Adler, professor in the physics department at St. Mary's College in Maryland, is one of us--he's a lifelong fan of SF, and he knows what he's talking about. And Wizards, Aliens, and Starships is a great book for Analog readers, as well as anyone who wants to write hard SF. I mean, it's got honest-to-goodness equations--and the book is dedicated to Poul Anderson... Wizards, Aliens, and Starships is a love letter to science fiction."--Don Sakers, Analog Science Fiction and Fact "Hugely entertaining and scientifically sound."--Paul Gilster, Centauri Dreams "What a fun book!"--Keith Cooper, Astronomy Now "Wizards, Aliens, and Starships manages to thread the needles of both scientific literacy and accuracy when it comes to the properties he's exploring. Whether it's conservation of mass in shapeshifting, lighting candles at Hogwarts, or building a planet, Adler keeps the science accessible and the fanboys and girls happy."--Glenn Dallas, San Francisco Book Review "Wizards, Aliens, and Starships [is] a book that combines my love for science and my love for science fiction... I did quite like this book and would recommend it for any academic library that collects popular science or science fiction. Large public libraries would also find this book to be useful as

Charles L. Adler is professor of physics at St. Mary's College of Maryland.

1 PLAYING THE GAME 1 1.1 The Purpose of the Book 1 1.2 The Assumptions I Make 3 1.3 Organization 4 1.4 The Mathematics and Physics You Need 5 1.5 Energy and Power 6 I POTTER PHYSICS 11 2HARRY POTTER AND THE GREAT CONSERVATION LAWS 13 2.1 The Taxonomy of Fantasy 13 2.2 Transfiguration and the Conservation of Mass 14 2.3 Disapparition and the Conservation of Momentum 16 2.4 Reparo and the Second Law of Thermodynamics 21 3WHY HOGWARTS IS SO DARK 27 3.1 Magic versus Technology 27 3.2 Illumination 28 4FANTASTIC BEASTS AND HOW TO DISPROVE THEM 38 4.1 Hic sunt Dracones 38 4.2 How to Build a Giant 39 4.3 Kleiber's Law, Part 1: Mermaids 45 4.4 Kleiber's Law, Part 2: Owls, Dragons, Hippogriffs, and Other Flying Beasts 49 II SPACE TRAVEL 57 5WHY COMPUTERS GET BETTER AND CARS CAN'T (MUCH) 59 5.1 The Future of Transportation 59 5.2 The Reality of Space Travel 61 5.3 The Energetics of Computation 63 5.4 The Energetics of the Regular and the Flying Car 64 5.5 Suborbital Flights 68 6VACATIONS IN SPACE 71 6.1 The Future in Science Fiction: Cheap, Easy Space Travel? 71 6.2 Orbital Mechanics 74 6.3 Halfway to Anywhere: The Energetics of Spaceflight 74 6.4 Financing Space Travel 82 7SPACE COLONIES 86 7.1 Habitats in Space 86 7.2 O'Neill Colonies 87 7.3 Matters of Gravity 89 7.4 Artificial "Gravity" on a Space Station 93 7.5 The Lagrange Points 103 7.6 Off-Earth Ecology and Energy Issues 106 7.7 The Sticker Price 112 8THE SPACE ELEVATOR 115 8.1 Ascending into Orbit 115 8.2 The Physics of Geosynchronous Orbits 116 8.3 What Is a Space Elevator, and Why WouldWeWant One? 118 8.4 Why Buildings Stand Up--or Fall Down 119 8.5 Stresses and Strains: Carbon Nanotubes 122 8.6 Energy, "Climbers," Lasers, and Propulsion 123 8.7 How Likely Is It? 125 8.8 The Unapproximated Elevator 127 9MANNED INTERPLANETARY TRAVEL 130 9.1 It's Not an Ocean Voyage or a Plane Ride 130 9.2 Kepler's Three Laws 131 9.3 The Hohmann Transfer Orbit 134 9.4 Delta v and All That 136 9.5 Getting Back 137 9.6 Gravitational Slingshots and Chaotic Orbits 138 9.7 Costs 142 10ADVANCED PROPULSION SYSTEMS 145 10.1 Getting There Quickly 145 10.2 Why Chemical Propulsion Won'tWork 146 10.3 The Most Famous Formula in Physics 147 10.4 Advanced Propulsion Ideas 148 10.5 Old "Bang-Bang": The Orion Drive 153 10.6 Prospects for Interplanetary Travel 155 11SPECULATIVE PROPULSION SYSTEMS 157 11.1 More Speculative Propulsion Systems 157 11.2 Mass Ratios for Matter-Antimatter Propulsion Systems 168 11.3 Radiation Problems 173 12INTERSTELLAR TRAVEL AND RELATIVITY 176 12.1 Time Enough for Anything 176 12.2 Was Einstein Right? 178 12.3 Some Subtleties 182 12.4 Constant Acceleration in Relativity 184 13FASTER-THAN-LIGHT TRAVEL AND TIME TRAVEL 188 13.1 The Realistic Answer 188 13.2 The Unrealistic Answer 188 13.3 Why FTL Means Time Travel 190 13.4 The General Theory 193 13.5 Gravitational Time Dilation and Black Holes 195 13.6 Wormholes and Exotic Matter 198 13.7 The Grandfather Paradox and Other Oddities 205 III WORLDS AND ALIENS 215 14DESIGNING A HABITABLE PLANET 217 14.1 Adler's Mantra 218 14.2 Type of Star 221 14.3 Planetary Distance from Its Star 226 14.4 The Greenhouse Effect 229 14.5 Orbital Eccentricity 232 14.6 Planetary Size and Atmospheric Retention 233 14.7 The Anna Karenina Principle and Habitable Planets 237 14.8 Imponderables 239 15THE SCIENTIFIC SEARCH FOR SPOCK 242 15.1 Exoplanets and Exoplants 242 15.2 Doppler Technique 246 15.3 Transits and the Kepler Mission 249 15.4 The Spectral Signatures of Life 250 15.5 Alien Photosynthesis 251 16THE MATHEMATICS OF TALKING WITH ALIENS 255 16.1 Three Views of Alien Intelligences 255 16.2 Motivation for Alien Contact 259 16.3 Drake-Equation Models and the Mathematics of Alien Contact 267 IV YEAR GOOGOL 273 17THE SHORT-TERM SURVIVAL OF HUMANITY 275 17.1 This Is the Way the WorldWill End 275 17.2 The Short-Term: Man-Made Catastrophes 275 18WORLD-BUILDING 292 18.1 Terraforming 292 18.2 Chara