If our universe is not unique, it is reasonable to wonder whether or not the laws of nature which we have discovered are unique. Put another way: Is there only one way to build a sensible universe? Is there some logical flaw that precludes the consistency of any other universe of 4 dimensions of space and time, with matter and radiation and forces between the particles, unless it is precisely the universe we live in? If so, then a Theory of Everything that explains the observed universe would truly explain how we came to be here. If not, then our existence and the associated laws of nature in our universe may not be particularly fundamental. The laws of physics we have derived may in fact be logically unrelated. As Weinberg put it: “Do they [the laws of physics] have the property that there is no small change that can be made in them without leading to nonsense?” Preskill put the same issue somewhat more poetically:
I am imagining that there is an oracle to consult. It knows everything, but I am allowed only one question, so I better use it wisely! There are so many things I would like to ask, but it is a delicate matter to phrase the question so that when I hear the answer I will understand what it means.… You did not say so, but I have decided to assume that the answer will be yes or no—I am going to acquire only one bit of information about the universe.
The question I will ask the oracle is: “Is physics an environmental science?”
Before it answers, I will explain to the oracle what the question is about. I want to know whether the features of the universe that we observe (for example, the values of fundamental constants such as cosmological constant, the fine-structure constant, masses of quarks and leptons, etc.) can really be predicted from first principles, or whether chance played a role in determining their values. Is our universe the only possible one, or one of many possible ones? If it is one of many possible ones, then we cannot understand the universe from first principles without observing some of its properties; i.e., physics is an environmental science (like biology). The universe that we inhabit depends on many “frozen accidents” that occurred early in its history.
In a way, this is a rephrasing of Einstein’s famous question: “Did God have any choice in creating the universe?” To me, it is important to know the answer, so we can establish what the ultimate goal of fundamental physics should be. We seek a “theory of everything,” a highly predictive theory of all the fundamental particles and forces. But perhaps even when we know this theory, many predictions will still elude us. If physics is actually an environmental science, then our dream of understanding why the universe is the way it is can never be fully realized.
So it seems that even the future of science may, in the end, depend on the nature of quantum mechanics. If quantum processes imply that even the creation of our universe was a probabilistic event, the circumstances associated with our existence may be vastly different from what one might have otherwise thought.
Still, as I reflect upon the future, it seems to me that even if quantum mechanics finally does turn out to imply that our existence is a bigger cosmic accident than previously thought, there remains a bright side for those who like to think that our existence is somehow significant. For, in the end, quantum mechanics might provide our ultimate salvation.
I began this book having fun with one science fiction vision of Doomsday, only to later argue that a much more serious end was in store for the Earth, independent of whatever evil plots any aliens may have in mind for us, since the Earth will be consumed by our own Sun in about 5 billion years. If we are lucky and/or resourceful, our DNA—or at least our intelligence, if we can pass that on to a silicon-based life-form (computers, not the Horta)—may survive that cataclysm, and some form of either one may venture out among the stars. But perils will still ensue. Eventually, if the visible universe does not recollapse in a Big Crunch, then in, say, 100 billion years, all the stars in our galaxy (and in everybody else’s) will have burned out, and any descendants will have to find new ways to store and use energy. Current ideas in particle physics suggest that somewhere around a million billion billion billion years from now, all matter itself will have decayed into radiation. That seems to herald the ultimate end of intelligence in the universe.
Or does it?
As long as there was energy to be mined, could we not continually recycle energy into matter, so that at least locally we could keep matter in a steady state? Not forever. The Second Law of Thermodynamics tells us that this stopgap measure must eventually fail, as the universe becomes a uniform heat bath in which no useful work can be done. But I like to think that even then there may remain some hope. If our observable universe is merely one of many possible universes, in each of which the laws of physics may vary, then there are at least two possibilities that come to mind for the continued evolution of intelligence. Either we may be able to create a new baby universe, which will evolve on its own and into which some remnant of our existence might escape before heat death engulfs the universe it leaves behind. Or else there is the more likely possibility that on sufficiently large scales the universe contains many separate domains, of which our observable universe is only a part. This metauniverse may have a structure wherein its subuniverses—each with different laws of physics, different fundamental constants, and so on—will eventually merge. (I am teetering on the edge of metaphysics here. When I connect this notion to ideas in physics which are at present more well defined, I suspect it’s more likely that such subuniverses will always remain causally disconnected. But one can always hope.) I have no idea what fireworks might ensue when two domains with different laws of physics merge. Whether it would be enough to give us a new beginning is anyone’s guess.
For now this territory may be best left to the science fiction writers. I invite you to imagine your own scenario. Who knows? I may see it at the movies soon. Or maybe I will write the screenplay. Regardless, my role has been something like that of the Ghost of Christmas Future: the purpose of these musings is not so much to argue that this is the way things will be as it is to inspire a consideration of the possibilities. Most important, I hope they have served as a reminder that even if aliens may not walk among us, in the long run truth will probably remain stranger than fiction.
EPILOGUE
I closed this book with a discussion of some possibilities for the future—both the future of physics and of the universe itself. In so doing, I was reminded of a question I was recently asked at a public forum: Might the best slogan for modern science be “The sky’s the limit?” I answered, in the cocksure manner I tend to adopt in such venues, “No, I think a better one is ‘We are limited only by our imaginations.’” I have since often wondered about that insouciant answer. Did I really believe what I was saying, or was it just a good sound bite? Was I morphing into a politician?
First, let me make clear that in originally saying this I never intended to suggest that there are no limits to what is possible in the physical universe. It is this mistaken notion as much as any other which drives me to write about science for the nonscientist. Science is based on limits: It proceeds by progressively finding out what is not possible, through experiment and theory, in order to determine how the universe might really function. It is worth recalling Sherlock Holmes’s adage that when you have eliminated all other possibilities, whatever remains, no matter how improbable, is the truth. Because of this, the universe is a pretty remarkable place even without all the extras.
The greatest gift science has bestowed upon humanity, in my opinion, is the knowledge that whether we like it or not, the universe is the way it is. Sometimes it is mysterious; sometimes it is banal. And as often as not, our imaginations are expanded, not constricted, by the need to conform to reality. Relativity and quantum mechanics were not invented because someone thought it would be a good idea for the universe to obey these rules; rather, these revolutionary ideas were forced upon us by nature. Learning how to work within this framework to achieve what we desire is perhaps the truest definition of intelligence. It is only by keeping our minds open
to the possibilities of existence, while being steadfast in our willingness to toss out what we may find attractive in favor of what actually occurs, that we can hope to unlock nature’s secrets.
While the demands of realism are clearly less exigent for science fiction than for science, I think that at a deep level this spirit of imagination tempered by reality, or at least what might make a plausible reality, is what characterizes the very best science fiction as well. I have tried whenever possible here to adopt a “What if… ?” attitude, but I like to recall when necessary the adage of New York Times publisher Arthur O. Sulzberger: “I like to keep an open mind, but not so open that my brains fall out.” At times, the weight of logic has not been kind to a number of possibilities that many people, including Hollywood producers, would earnestly like to believe in. To those who are dismayed by my arguments, I hope this book will be taken as a challenge. What very much bothers me in certain discussions of topics at the boundary between science and science fiction are the sometimes pejorative references to “conventional science.” Often “conventional” scientists are viewed as closed-minded and conservative, while those willing to bypass the problematic issues associated with experiment are viewed as open-minded and enlightened. This seems backwards. I think that people who are willing to force their imaginations to follow the sometimes subtle signposts of nature are the ones with the open minds, not those who are uncritically willing to accept a universe that reflects their own pet theories and desires.
At the same time, we must be thankful for the mysteries. The inexplicable is what fuels our imagination. The mysteries sustain the human spirit. As I think about the future of physics, it is possible to imagine a world in which all the big puzzles are solved. As fascinating as it would be to have the answers to the questions presented by my colleagues in this book, having the answers will, I expect, never be as satisfying or as stimulating as the search for them. The mysteries drive the connection between science and science fiction which I heralded at the outset, and celebrating them is really what science, literature, and art—not to mention my own books—are all about.
There is plenty of wonder left in the universe even after we have examined all the clues nature has thrown our way. I really believe that our imaginations have not even begun to exhaust the possibilities of existence. To proclaim the slogan “The Truth Is Out There” is perhaps too trite. I prefer “You ain’t seen nothin’ yet!”
ACKNOWLEDGMENTS
It is always a particular pleasure to reach this point in a book, when I can sit back and reflect on all the people whose generosity with time and information made the writing possible.
With each book, the list seems to get longer.
First and foremost, I want to thank my former editor, Susan Rabiner, whose advice and wisdom I have grown to depend on through two and a half books. After Susan helped me conceptualize this one, following our successful partnership on The Physics of Star Trek, Basic Books—her employer and the publisher of three of my books—was disbanded by HarperCollins midway into the book’s writing. Susan and the rest of the staff at Basic went their separate ways, and I am looking forward to working with her, one way or another, in the future.
Mauro DiPreta, my new editor at HarperCollins, had the unenviable task of jumping in in midstream, and he did it with intelligence and humor, turning what could have been an uncomfortable situation into one that was productive and enjoyable. His comments were often very useful, even when I think he did not expect them to be. I also thank Mauro’s assistant, Molly Hennessey, for arranging so many different things. Stephanie Lehrer, of HarperCollins’s Publicity Department, began working hard on this book even before it was finished, and I thank her for her efforts.
Sara Lippincott, who helped fine-tune The Physics of Star Trek, jumped into the final editorial fray and after an intense couple of weeks of Fax Wars left the final manuscript in much better shape than I am sure it would have been otherwise.
And now to my physics colleagues from around the world. Each time I have turned to them for input, I’ve been agreeably surprised and gratified at how generous they are with their time—and, more than that, at how seriously they have taken these projects. This time around, I want to particularly thank Sheldon Glashow, John Preskill, Kip Thorne, Steven Weinberg, Frank Wilczek, and Ed Witten for their thoughtful responses to my queries.
Regarding the specific subjects treated in this book, I have benefited from a number of sources. My experimental colleagues at CERN, the European Center for Nuclear Research, where I spent a pleasant 6 months during part of the writing of this book, were quite helpful in updating me on issues related to antimatter production and storage. In particular, Rolf Landua spent time discussing the new Athena antimatter decelerator with me. I found Robert Zubrin and Richard Wagner’s book, The Case for Mars (New York: The Free Press, 1996), a useful reference on various details of the “Mars Direct” proposal. On issues related to ESP and its history, among the various sources I looked at was a particularly useful one I picked up at the CERN library, titled Physics and Psychics, by a fellow particle physicist, Victor Stenger (Buffalo, N.Y.: Prometheus Books, 1990). As should also be clear from the text, Roger Penrose’s books, particularly his Shadows of the Mind (New York: Oxford University Press, 1994), were helpful in crystalizing my own thinking about issues of consciousness and computing, even if I happen to disagree with some of his conclusions. On issues of quantum computing I benefited not only from the published literature but also from a particularly informative colloquium at the University of Geneva given by the IBM physicist David DiVincenzo. On certain issues of quantum measurement, I found a rereading of the final chapters of David Lindley’s Where Does the Weirdness Go? (New York: Basic Books, 1996), which I had earlier reviewed for Natural History, useful, even if I am not fully in agreement with all his arguments.
Some of the ideas discussed here have appeared in pieces I wrote for various magazines. A short discussion of a few of the points from chapter 1 appeared in Wizard Magazine, and parts of chapters 2 through 5 are adapted from an article I wrote for Discover on getting to Mars.
I also want to thank the organizers of the 1997 Workshop on the Search for Extraterrestrial Intelligence for inviting me to Naples to speak at the meeting. I found that during the writing of this book I referred often to the notes I took there. I particularly thank Paolo Strolin for introducing me and my family to the joys of Napoli.
Like my last two books, Beyond Star Trek was essentially completed in Aspen, which provides a wonderful haven of culture, beauty, and solitude in which to work; I thank my friends and acquaintances in Aspen for making us always feel so much at home. This book really began, however, and was truly completed, at home in Cleveland. To the people of this warm and hospitable place, and to our many colleagues, close friends, and acquaintances there, heartfelt thanks for adopting my family and me so graciously.
As it has been with all of my books, the ongoing support of my wife, Kate, and daughter, Lilli, has been absolutely essential. This time around—in tighter quarters than normal, while we were traveling—they were particularly indulgent with their time and patience, and I thank them. Once again, I hope they will enjoy the ride that is to come.
Finally, I wish to thank all the readers of The Physics of Star Trek and others who so kindly wrote to me with questions and comments, and who came to lectures and book signings—and also the newspaper, radio, and television interviewers. Your questions were often much more thought-provoking than you may have realized, and in the final analysis you are of course what this whole endeavor is all about.
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Beyond Star Trek Page 17
