Fear of a Black Universe Read online

  At Las Cuevas Bay, after gazing at the waves for some time, I had an epiphany: Who better to help us address our questions than Einstein himself? What if we had a bird’s-eye view of the jungle of physics from which we could see the origins of the theories and the interconnections between the laws that give rise to (and constrain) them? Would this perspective facilitate our attempts at reworking these theories to better address our contemporary questions? Could we turn from calculating, boring physicists to brave adventurers, imagining worlds no one else had seen before?

  During my time as a postdoctoral researcher in theoretical physics at the Stanford Linear Accelerator Center (SLAC), I received a surprising letter from the National Geographic Society. I wondered if I owed them a payment. Instead, the letter congratulated me on being selected as a National Geographic Emerging Explorer. I was both elated and confused. I had never applied to be an explorer, nor did I think of myself as one. When it turned out that it was not, in fact, a mistake, I was deeply honored and did not say no to the monetary prize and subsequent trips to National Geographic headquarters to meet other explorers I admired. For example, I had always wanted to meet ethnobotanist Wade Davis, whose book was the basis for one of my favorite horror movies, The Serpent and the Rainbow.

  All explorers were invited to a fundraiser and to celebrate the seventieth birthday of the Society’s president at the time, Gil Grosvenor. There were many impressive people there, and I quickly started to feel a little out of place. Among the newly elected explorers was an underwater cave diver who could contort his body to fit into intricate caves for hours, hundreds of feet under the ocean. There was a woman who lived among lions in the Serengeti, and a man who explored and lived in Antarctica for extended periods. At the fundraiser, each explorer was placed at a dinner table with a group of potential donors, to entertain them. After we introduced ourselves, one disappointed donor said to me, “You don’t hang out in the jungle? You don’t fly airplanes? Why did they make a theoretical physicist an explorer?!”

  I didn’t want the donor to feel duped. So as a good spokesperson for National Geographic, I responded with conviction: “I explore the cosmos with my mind.” I went on to explain how the worlds that cosmologists explore are even more extreme than explorers on Earth, so extreme that we are forced to explore them in our imaginations. I went on to explain that Einstein explored the nature of space-time, and this led to the ultimate prediction and discovery of a supermassive black hole at the center of our galaxy. Try exploring that physically! Some donors were interested, but others wanted to hang out with a “real” explorer.

  Despite the drama, that night got me thinking about the similarities between physical and mental exploration, about the extreme places theoretical physicists must explore to make progress. These mental explorations are the fuel for discovering and clarifying physical theories; they are the domain of Einstein’s notion of principle theories.

  In 1914, soon after his revolutionary discoveries in quantum mechanics and relativity, Einstein gave an address to the Prussian Academy of Sciences in which he discussed his strategy for discovery in theoretical physics. “The theorist’s method involves his using as his foundation general principles from which he can deduce conclusions,” Einstein said. “His work thus falls into two parts. He must first discover his principles and then draw the conclusions which follow from them.”

  Einstein could perceive a hidden reality, where time and space could slow down, speed up, bend, and even cease to exist, a reality that transcends the limits of our daily perceptions, a reality that makes no sense to us when we are thinking commonsensically. Surely there are still new levels of reality that are hidden, and like Einstein we ought to be curious to know what lies beyond our current (commonsensical) understanding in physics.

  As a student, I had mistakenly thought that physics was driven mostly by mathematics and logical reasoning. Einstein’s conviction was that principles are the driving force behind new discoveries, while mathematics is necessary to make physics precise, to inform the clarification of the principles, to explain and clarify our characterizations of how we conceptualize phenomena, and to make predictions. In short, math is not enough; it is a tool. The important question is how does one come up with new principles? Einstein answers: “Here there is no method capable of being learned and systematically applied so that it leads to a new [principle]. The scientist has to worm these principles out of nature by perceiving in comprehensive complexes of empirical facts certain general features which permit of precise formulation.”

  He was saying that a scientist should make connections and see patterns across a range of experimental outcomes, which may not be related to each other in an obvious way. Once the scientist ekes out these patterns, she makes a judgment call as to whether a new principle of nature is necessary. But this is misleading. Facts are statements about phenomena, but they don’t exist on their own; they are always conceptualized, which means that they are, if only implicitly, constructed theoretically. Experiments allow us to answer theoretically constructed questions. Theory tells us what “facts” to look for.

  As an adolescent Einstein was free to play in his father’s electrical company in Pavia, Italy. This play fertilized his imagination; it enabled him to envisage what he would experience if he could catch up to a light wave. His process of “worming” out these principles entails visualizing phenomena that are not directly accessible to our senses or current experiments. It eventually enabled him to formulate theories that told us what we would find and helped us to understand where we might look to find it.

  How did Einstein know when to postulate his theory of relativity? How, aside from his natural-born genius, was he able to arrive at his principles? I found part of the answer in a lecture he gave at Oxford University in 1933. “[The discovery of principles] are free inventions of the human intellect, which cannot be justified either by the nature of that intellect or in any other fashion a priori,” he said. But what does Einstein mean by this? Sometimes to get around a scientific problem, one must consider possibilities that defy the rules of the game. If you don’t enable your mind to freely create sometimes strange and uncomfortable new ideas, no matter how absurd they seem, no matter how others view your arguments or punish you for making them, you may miss the solution to the problem. Of course, to do this successfully, it is important to have the necessary technical tools to turn the strange idea into a determinate theory.

  When I told the donors at National Geographic that I explored the cosmos with my mind, I wasn’t jiving. Those theoretical physicists who explored with their intellect, making “free inventions,” sounded to me like masters of improvisation. Einstein gave me the hall pass to continue my free inventions. But, like Einstein did, we must first look to the fundamental principles underlying modern physics and use them to explore some of the big mysteries physicists face. In the pages that follow, we will engage in free inventions, trying to cook up some new physics while journeying through some of the biggest mysteries at the frontiers of cosmology and fundamental physics. While some of the ideas presented in this book are debatable and speculative, I hope that it nonetheless provides not only insight into how a theoretical physicist dreams up new ideas and sharpens them into a consistent framework but also, perhaps, the inspiration to think of your own big ideas.

  2

  THE CHANGELESS CHANGE

  A new idea comes suddenly and in a rather intuitive way. That means it is not reached by conscious logical conclusions. But, thinking it through afterward, you can always discover the reasons which have led you unconsciously to your guess and you will find a logical way to justify it.

  —ALBERT EINSTEIN

  After many years spent developing my skills and ideas until they were good enough for publication in physics journals, I finally published my first independent paper in the Journal of High Energy Physics. My article made an iconoclastic claim: Einstein’s cherished idea of a constant speed of light could be violated in the early un
iverse if our actual universe were a three-dimensional membrane orbiting a five-dimensional black hole. If this sounds like gobbledygook to you, in hindsight, it is. But twenty years ago, such subject matter was typical of what theorists worked on as they were trying to integrate cosmology and string theory. I was especially proud that the months of calculations I performed within the framework of string theory provided these new solutions.

  And so there I was, excited to give my first professional talk at a picturesque university nestled in the mountains of Vancouver, Canada. They were my calculations I was going to talk about, so I knew them inside out, which contributed to my air of overconfidence. It didn’t last long. Within five minutes of my talk’s beginning, I was blasted with questions that soon transformed into a flood of criticism. Attempts to continue my talk ricocheted against random comments, delivered with a tone of unfriendliness, from the audience, attacking the premise of the talk: “Why should we believe our universe is a brane rotating around a 5D black hole?” I couldn’t help but feel unwelcome and alienated. By the middle of the talk I stood dejected, my fears of not being accepted as a peer erupting to the surface of my mind. Just because your paper gets published doesn’t mean that you will get into the club of physics. That day it felt obvious I hadn’t.

  Then came a voice from the back of the room. The speaker was a distinguished Indian physicist in his seventies decked out in a well-groomed tweed suit. As soon as he began to speak, everyone shut up, as if a demigod commanded his minions to silence.

  The old man stood up and said, “Let him finish! No one ever died from theorizing.”

  It was the biggest lesson with the fewest words the audience and I could have learned about the art of theoretical physics. Those words would stay with me throughout my life as a theoretician. I took the old man’s admonition as a reminder to never be afraid of even the most absurd ideas, and to even embrace them. I finished my talk without further interruption and even got a round of applause afterward. Did I take my theory seriously years later? No, but the exercise of journeying into a theoretical territory and then journeying back has proven time and time again to be useful in surveying what’s possible and, hopefully, what describes and predicts the real universe. That moment was pivotal in my life and how I would engage the art of theoretical physics for the next twenty years.

  A year after that talk, after many failed attempts, I landed a job as a postdoctoral researcher in theoretical physics at Imperial College in London. The department had been founded by Abdus Salam, who, along with Sheldon Glashow and Steven Weinberg, would win the Nobel Prize in Physics for discovering a unified theory of the weak nuclear interaction with electromagnetism. I was excited to be following in Salam’s footsteps along the road to becoming a research physicist. Yet somehow, despite my excitement, I quickly realized that road was not what I thought it would be.

  At Imperial, weeks and then months of work could pass with little to show for it. If an idea did come to me, I invariably and quickly discovered that someone had already developed and published it. If I was performing a calculation, I would often hit a roadblock and have to learn new mathematical techniques in order to tackle it. By the time I learned the new math, someone would have already hit the finish line and published the result before me. These experiences forced me to wake up from my theory dreams to a reality in which the prospect of becoming a scientist seemed dim. My contract was for two years, but I relegated my expectations to another career, perhaps going on the road as a jazz musician or teaching high school physics, both admirable things to do. I would continue trying my best, but ideas simply weren’t coming, and I would continue to fake it and keep these frustrations to myself. I had everyone fooled.

  Then one seemingly uneventful day, horror hit me. I received an email from our theory group administrator that simply said: “Professor Isham would like to speak with you.” I turned white like a ghost. Chris Isham was the head of our theory group and I feared that he had figured out that I was a fake. Everyone in our group revered Isham for his exceptional abilities in quantum gravity and mathematical physics. He was a tall Englishman with dark hair and piercing eyes and who walked with a slight limp. Like his friend and classmate Stephen Hawking, Isham suffered a rare neurological disorder that kept him in constant pain. I had kept away from him in fear of letting some gibberish slip out to ignite his physics bullshit detector. Now I suspected and feared that he had figured it out on his own, and my day had come to face him.

  I decided to do a little preparation and read one of Isham’s papers. Perhaps I could appease him. To my dismay, many of his publications involved some of the most advanced concepts in math and physics, with inscrutable names such as topos theory, quantum logic, C-star algebras, and so on. I finally found a paper that he’d written two decades ago that I could grasp. It was about the behavior of quantum particles with half-integer spin, called fermions, in an expanding gravitational cosmology. Electrons, quarks, neutrinos, and most matter are examples of fermions, so it might seem a safe topic. Still, I set off nervously for the meeting.

  I tensely walked into his large office filled with books, incomprehensible equations, and diagrams. On his desk an oddly placed small statue of an angel faced a visitor. After a brief hello, Isham didn’t waste time.

  “Why are you here?”

  I kept it real. “I want to be a good physicist.”

  To my surprise, he said with a serious demeanor, “Then stop reading those physics books!” Then he pointed to an isolated bookshelf. “You see those books over there? They are the complete works of Carl Jung. Do you know that Wolfgang Pauli and Jung corresponded for decades? And Pauli’s dreams and analysis were key to his discovery of the quantum exclusion principle.”

  Isham revealed that he had been studying Jung over the last fifteen years and had trained himself to do calculations in his dreams. I couldn’t believe that I was hearing this from one of the master mathematical physicists on the planet. Then he had a eureka smile and said, “You know what? How about you come to my office once a week? Write down your dreams and tell me about them.” He suggested that I read Jung’s Volume I, book 9 entitled Aion: Researches into the Phenomenology of Self as well as Atom and Archetype, a collection of two decades of letters between Jung and Pauli. At first, I was skeptical of the experiment. But I was also feeling isolated in the theory group, and Isham’s invitation to talk about my dreams was an opportunity to spend quality time with one of my physics idols.

  Our weekly discussions started with me telling him about random dreams that had no apparent relation to physics, such as those about past relationships that continued to taunt me. During our time together, Isham would share his perspectives on some of the mysteries that our field faced. One of those was the problem of time in quantum gravity. While our physical (and psychological) experience of the flow of time is taken as fact, time disappears in the equations of quantum gravity. Isham worked on this problem and was a proponent of a new notion of time called internal time. It was no surprise to me to learn that these ideas were inspired by his exploration of psychology and mysticism.

  As the weeks passed, I told Isham about what I thought was a trivial dream. In Jungian philosophy, dreams sometimes allow us to confront our shadows with the appearances of symbols called archetypes. I saw one here. I was suspended in outer space and an old, bearded man in a white robe—it wasn’t God—was silently and rapidly scribbling incomprehensible equations on a whiteboard. I admitted to the old man that I was too dumb to know what he was trying to show me. Then the board disappeared, and the old man made a spiraling motion with his right hand. Isham was captivated by this dream and asked, “What direction was he rotating his hands?” I was baffled as to why he was interested in this detail. But two years later, while I was a new postdoc at Stanford, I was working on one of the big mysteries in cosmology—the origin of matter in the universe—when the dream reappeared and provided the key insight to constructing a new mechanism based on the phenomenon of cosmic inf
lation, the rapid expansion of space in the early universe. The direction of rotation of the old man’s hand gave me the idea that the expansion of space during inflation would be related to a symmetry that resembled a corkscrew motion that elementary particles have called helicity. The resulting publication was key to earning me tenure and a national award from the American Physics Society. Chris Isham’s method proved to work for me. But he and I weren’t alone here. It turns out that some of the biggest breakthroughs in science were inspired by dreams, including Einstein’s theory of relativity.

  Beginning when Einstein was a teenager hanging out in his father’s electric lighting company, he would play with imaginations about the nature of light. He would try to become one with a beam of light and wondered what he would see if he could catch up to a light wave. This matter found itself in the playground of Einstein’s subconscious and revealed a paradox in a dream. It is said that Einstein dreamt of himself overlooking a peaceful green meadow with cows grazing next to a straight fence. At the end of the fence was a sadistic farmer who occasionally pulled a switch that sent an electrical current down the fence. From Einstein’s birds-eye view he saw all the electrocuted cows simultaneously jump up. When Einstein confronted the devious farmer, there was a disagreement as to what happened. The farmer persisted that he saw the cows cascade in a wavelike motion. Einstein disagreed. Both went back and forth with no resolution. Einstein woke up from this dream with a paradox.

  In the account of Einstein’s dream, and other accounts of the role of dreams in creative work, such as music, science, and visual art, there is a common theme: a paradox is revealed through imaginations that are contradictory in the awake state. It’s as if the mind’s eye can access an intuition beyond the waking state and not restrict our imaginations to the self-editing that our conditioning might impose during the waking state (unless you’re a great daydreamer). Perhaps dreams are an arena that can enable supracognitive powers to perform calculations and perceptions of reality that may be incomprehensible in our wake state. In my case, my paradox was making an equivalence between incomprehensible equations presented by the bearded man and his counterclockwise whirling hands. This counterclockwise motion turned out to summarize the mathematics that was obscuring the underlying physics to be unveiled.