The Science of Interstellar Read online

  CONTENTS

  Foreword

  Preface

  1 A Scientist in Hollywood: The Genesis of Interstellar

  I. FOUNDATIONS

  2 Our Universe in Brief

  3 The Laws That Control the Universe

  4 Warped Time and Space, and Tidal Gravity

  5 Black Holes

  II. GARGANTUA

  6 Gargantua’s Anatomy

  7 Gravitational Slingshots

  8 Imaging Gargantua

  9 Disks and Jets

  10 Accident Is the First Building Block of Evolution

  III. DISASTER ON EARTH

  11 Blight

  12 Gasping for Oxygen

  13 Interstellar Travel

  IV. THE WORMHOLE

  14 Wormholes

  15 Visualizing Interstellar’s Wormhole

  16 Discovering the Wormhole: Gravitational Waves

  V. EXPLORING GARGANTUA’S ENVIRONS

  17 Miller’s Planet

  18 Gargantua’s Vibrations

  19 Mann’s Planet

  20 The Endurance

  VI. EXTREME PHYSICS

  21 The Fourth and Fifth Dimensions

  22 Bulk Beings

  23 Confining Gravity

  24 Gravitational Anomalies

  25 The Professor’s Equation

  26 Singularities and Quantum Gravity

  VII. CLIMAX

  27 The Volcano’s Rim

  28 Into Gargantua

  29 The Tesseract

  30 Messaging the Past

  31 Lifting Colonies off Earth

  Where Can You Learn More?

  Some Technical Notes

  Acknowledgments

  Figure Credits

  Bibliography

  Index of People

  Index of Subjects

  FOREWORD

  One of the great pleasures of working on Interstellar has been getting to know Kip Thorne. His infectious enthusiasm for science was obvious from our first conversation, as was his reluctance to proffer half-formed opinions. His approach to all the narrative challenges that I threw him was always calm, measured and above all, scientific. In trying to keep me on the path of plausibility, he never showed impatience with my unwillingness to accept things on trust (although my two-week challenge to his faster-than-light prohibition might have elicited a gentle sigh).

  He saw his role not as science police, but as narrative collaborator—scouring scientific journals and academic papers for solutions to corners I’d written myself into. Kip has taught me the defining characteristic of science—its humility in the face of nature’s surprises. This attitude allowed him to enjoy the possibilities that speculative fiction presented for attacking paradox and unknowability from a different angle—storytelling. This book is ample demonstration of Kip’s lively imagination and his relentless drive to make science accessible to those of us not possessed of his massive intellect or his immense body of knowledge. He wants people to understand and get excited about the crazy truths of our universe. This book is structured to let the reader dip in to a topic as deeply as their affinity for science prompts them—no one is left behind, and everyone gets to experience some of the fun I had trying to keep up with Kip’s agile mind.

  Christopher Nolan

  Los Angeles, California

  July 29, 2014

  PREFACE

  I’ve had a half-century-long career as a scientist. It’s been joyously fun (most of the time), and has given me a powerful perspective on our world and the universe.

  As a child and later as a teenager, I was motivated to become a scientist by reading science fiction by Isaac Asimov, Robert Heinlein, and others, and popular science books by Asimov and the physicist George Gamow. To them I owe so much. I’ve long wanted to repay that debt by passing their message on to the next generation; by enticing youths and adults alike into the world of science, real science; by explaining to nonscientists how science works, and what great power it brings to us as individuals, to our civilization, and to the human race.

  Christopher Nolan’s film Interstellar is an ideal messenger for that. I had the great luck (and it was luck) to be involved with Interstellar from its inception. I helped Nolan and others weave real science into the film’s fabric.

  Much of Interstellar’s science is at or just beyond today’s frontiers of human understanding. This adds to the film’s mystique, and it gives me an opportunity to explain the differences between firm science, educated guesses, and speculation. It lets me describe how scientists take ideas that begin as speculation, and prove them wrong or transform them into educated guesses or firm science.

  I do this in two ways: First, I explain what is known today about phenomena seen in the movie (black holes, wormholes, singularities, the fifth dimension, and the like), and I explain how we learned what we know, and how we hope to master the unknown. Second, I interpret, from a scientist’s viewpoint, what we see in Interstellar, much as an art critic or ordinary viewer interprets a Picasso painting.

  My interpretation is often a description of what I imagine might be going on behind the scenes: the physics of the black hole Gargantua, its singularities, horizon, and visual appearance; how Gargantua’s tidal gravity could generate 4000-foot water waves on Miller’s planet; how the tesseract, an object with four space dimensions, could transport three-dimensional Cooper through the five-dimensional bulk; . . .

  Sometimes my interpretation is an extrapolation of Interstellar’s story beyond what we see in the movie; for example, how Professor Brand, long before the movie began, might have discovered the wormhole, via gravitational waves that traveled from a neutron star near Gargantua through the wormhole to Earth.

  These interpretations, of course, are my own. They are not endorsed by Christopher Nolan any more than an art critic’s interpretations were endorsed by Pablo Picasso. They are my vehicle for describing some wonderful science.

  Some segments of this book may be rough going. That’s the nature of real science. It requires thought. Sometimes deep thought. But thinking can be rewarding. You can just skip the rough parts, or you can struggle to understand. If your struggle is fruitless, then that’s my fault, not yours, and I apologize.

  I hope that at least once you find yourself, in the dead of night, half asleep, puzzling over something I have written, as I puzzled at night over questions that Christopher Nolan asked me when he was perfecting his screenplay. And I especially hope that, at least once in the dead of night, as you puzzle, you experience a Eureka moment, as I often did with Nolan’s questions.

  I’m grateful to Christopher Nolan, Jonathan Nolan, Emma Thomas, Lynda Obst, and Steven Spielberg for welcoming me into Hollywood, and giving me this wonderful opportunity to fulfill my dream, to pass on to the next generation my message of the beauty, the fascination, and the power of science.

  Kip Thorne

  Pasadena, California

  May 15, 2014

  THE SCIENCE OF

  INTERSTELLAR

  1

  A Scientist in Hollywood:

  THE GENESIS OF INTERSTELLAR

  Lynda Obst, My Hollywood Partner

  The seed for Interstellar was a failed romance that warped into a creative friendship and partnership.

  In September 1980, my friend Carl Sagan phoned me. He knew I was a single father, raising a teenaged daughter (or trying to do so; I wasn’t very good at it), and living a Southern California single’s life (I was only a bit better at that), while pursuing a theoretical physics career (at that I was a lot bett
er).

  Carl called to propose a blind date. A date with Lynda Obst to attend the world premier of Carl’s forthcoming television series, Cosmos.

  Lynda, a brilliant and beautiful counterculture-and-science editor for the New York Times Magazine, was recently transplanted to Los Angeles. She had been dragged there kicking and screaming by her husband, which contributed to their separation. Making the best of a seemingly bad situation, Lynda was trying to break into the movie business by formulating the concepts for a movie called Flashdance.

  The Cosmos premier was a black-tie event at the Griffith Observatory. Klutz that I was, I wore a baby-blue tuxedo. Everybody who was anybody in Los Angeles was there. I was completely out of my element, and had a glorious time.

  For the next two years, Lynda and I dated on and off. But the chemistry just wasn’t right. Her intensity enthralled and exhausted me. I debated whether the exhaustion was worth the highs, but the choice wasn’t mine. Perhaps it was my velour shirts and double-knit pants; I don’t know. Lynda soon lost romantic interest in me, but something better was growing: a lasting and creative friendship and partnership between two very different people, from very different worlds.

  Fast-forward to October 2005, another of our occasional one-on-one dinners, where conversation would range from recent cosmological discoveries, to left-wing politics, to great food, to the shifting sands of moviemaking. Lynda by now was among Hollywood’s most accomplished and versatile producers (Flashdance, The Fisher King, Contact, How to Lose a Guy in Ten Days). I had married. My wife, Carolee Winstein, had become best friends with Lynda. And I’d not done badly in the world of physics.

  Over dinner, Lynda described an idea she had conceived for a science-fiction movie and asked me to help her flesh it out. This would be her second venture into science fiction: a collaboration with me, modeled on her previous collaboration with Carl Sagan on the movie Contact.

  I never imagined myself helping create a movie. I never coveted a presence in Hollywood, beyond a vicarious one, through Lynda’s adventures. But working with Lynda appealed to me, and her ideas involved wormholes, an astrophysics concept I had pioneered. So she easily lured me into brainstorming with her.

  During the next four months, over a few dinners and e-mails and phone calls, we formulated a rough vision for the film. It included wormholes, black holes, and gravitational waves, a universe with five dimensions, and human encounters with higher-dimensional creatures.

  But most important to me was our vision for a blockbuster movie grounded from the outset in real science. Science at and just beyond the frontiers of human knowledge. A film in which the director, screenwriters, and producers respect the science, take inspiration from it, and weave it into the movie’s fabric, thoroughly and compellingly. A film that gives the audience a taste of the wondrous things that the laws of physics can and might create in our universe, and the great things humans can achieve by mastering the physical laws. A film that inspires many in the audience to go learn about the science, and perhaps even pursue careers in science.

  Nine years later, Interstellar is achieving all we envisioned. But the path from there to here has been a bit like the “Perils of Pauline,” with many a spot where our dream could have collapsed. We acquired and then lost the legendary director Steven Spielberg. We acquired a superb young screenwriter, Jonathan Nolan, and then lost him twice, at crucial stages, for many months each. The movie sat in limbo, directorless, for two and a half years. Then, wondrously, it was resurrected and transformed in the hands of Jonathan’s brother, Christopher Nolan, the greatest director of his young generation.

  Steven Spielberg, the Initial Director

  In February 2006, four months after we began brainstorming, Lynda had lunch with Todd Feldman, Spielberg’s agent at the Creative Artists Agency, CAA. When Feldman asked what movies she was working on, she described her collaboration with me, and our vision for a sci-fi movie with real science woven in from the outset—our dream for Interstellar. Feldman got excited. He thought Spielberg might be interested and urged Lynda to send him a treatment that very day! (A “treatment” is a description of the story and characters, usually twenty pages or longer.)

  All we had in writing were a few e-mail exchanges and notes from a few dinner conversations. So we worked at whirlwind speed for a couple of days to craft an eight-paged treatment we were proud of, and sent it off. A few days later Lynda e-mailed me: “Spielberg has read it and is very interested. We may need to have a little meeting with him. Game? XX Lynda.”

  Of course I was game! But a week later, before any meeting could be arranged, Lynda phoned: “Spielberg is signing on to direct our Interstellar!” Lynda was ecstatic. I was ecstatic. “This kind of thing never happens in Hollywood,” she told me. “Never.” But it did.

  I then confessed to Lynda that I had seen only one Spielberg movie in my life—ET, of course. (As an adult, I had never been all that interested in movies.) So she gave me a homework assignment: Spielberg Movies Kip Must Watch.

  A month later, on March 27, 2006, we had our first meeting with Spielberg—or Steven, as I began to call him. We met in a homey conference room in the heart of his movie production company Amblin, in Burbank.

  At our meeting, I suggested to Steven and Lynda two guidelines for the science of Interstellar:

  1.Nothing in the film will violate firmly established laws of physics, or our firmly established knowledge of the universe.

  2.Speculations (often wild) about ill-understood physical laws and the universe will spring from real science, from ideas that at least some “respectable” scientists regard as possible.

  Steven seemed to buy in, and then accepted Lynda’s proposal to convene a group of scientists to brainstorm with us, an Interstellar Science Workshop.

  The workshop was on June 2 at the California Institute of Technology (Caltech), in a conference room down the hall from my office.

  It was an eight-hour, free-wheeling, intoxicating discussion among fourteen scientists (astrobiologists, planetary scientists, theoretical physicists, cosmologists, psychologists, and a space-policy expert) plus Lynda, Steven, and Steven’s father Arnold, and me. We emerged, exhausted but exhilarated with a plethora of new ideas and objections to our old ideas. Stimuli for Lynda and me, as we revised and expanded our treatment.

  It took us six months due to our other commitments, but by January 2007 our treatment had grown to thirty-seven pages, plus sixteen pages about the science of Interstellar.

  Jonathan Nolan, the Screenwriter

  In parallel, Lynda and Steven were interviewing potential screenwriters. It was a long process that ultimately converged on Jonathan Nolan, a thirty-one-year-old who had coauthored (with his brother Christopher) just two screenplays, The Prestige and The Dark Knight, both big hits.

  Jonathan, or Jonah as his friends call him, had little knowledge of science, but he was brilliant and curious and eager to learn. He spent many months devouring books about all the science relevant to Interstellar and asking probing questions. And he brought to our film big new ideas that Steven, Lynda, and I embraced.

  Jonah was wonderful to work with. He and I brainstormed together many times about the science of Interstellar, usually over a two- or three-hour lunch at the Caltech faculty club, the Athenaeum. Jonah would come to lunch brimming with new ideas and questions. I would react on the spot: this is scientifically possible, that isn’t, . . . My reactions were sometimes wrong. Jonah would press me: Why? What about . . . ? But I’m slow. I would go home and sleep on it. In the middle of the night, with my gut reactions suppressed, I would often find some way to make what he wanted to work, work. Or find an alternative that achieved the end he sought. I got good at creative thinking when half asleep.

  The next morning, I would assemble the semicoherent notes I had written during the night, decipher them, and write Jonah an e-mail. He would respond by phone or e-mail or another lunch,
and we would converge. In this way we came to gravitational anomalies, for example, and the challenge of harnessing them to lift humanity off Earth. And I discovered ways, just beyond the bounds of current knowledge, to make the anomalies scientifically possible.

  At crucial times we brought Lynda into the mix. She was great at critiquing our ideas and would send us spinning off in new directions. In parallel with our brainstorming, she was working her magic to keep Paramount Pictures at bay so we could maintain our creative autonomy, and planning the next phases of turning Interstellar into a real movie.

  By November 2007, Jonah, Lynda, Steven, and I had agreed on the structure for a radically revised story based on Lynda’s and my original treatment, Jonah’s big ideas, and the many other ideas that arose from our discussions—and Jonah was deep into writing. Then, on November 5, 2007, the Writers Guild of America called a strike. Jonah was forbidden to continue writing, and disappeared.

  I panicked. Will all our hard work, all our dreams, be for naught? I asked Lynda. She counseled patience, but was clearly very upset. She vividly tells the story of the strike in scene 6 of her book Sleepless in Hollywood. The scene is titled “The Catastrophe.”

  The strike lasted three months. On February 12, when it ended, Jonah returned to writing and to intense discussions with Lynda and me. Over the next sixteen months, he produced a long, detailed outline for the screenplay, and then three successive drafts of the screenplay itself. When each was finished, we met with Steven to discuss it. Steven would ask probing questions for an hour or more before proffering suggestions, requests, or instructions for changes. He was not very hands-on, but he was thoughtful, incisive, creative—and sometimes firm.

  In June 2009, Jonah gave Steven draft 3 of the screenplay, and disappeared from the scene. He had long ago committed to write The Dark Knight Rises, and had been delaying for month after month while working on Interstellar. He could delay no more, and we were without a screenwriter. On top of that, Jonah’s father became gravely ill. Jonah spent many months in London by his father’s side, until his father’s death in December. Through this long hiatus, I feared that Steven would lose interest.