The Fabric of the Cosmos: Space, Time, and the Texture of Reality
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by Brian Greene
576 pages, $28.95
Can you access the flash of emancipation you felt the first time you were able to stay up on a bike or propel yourself through the water? Can you remember the way your new knowledge enhanced your life? And can you recall the gratitude you felt toward those people who had the skill and the patience to pass that knowledge along to you?
While many of us have successfully moved past the learning challenges associated with biking and swimming, there remain concepts to master. Among them are phenomena that impact everything we think, do, and say—including biking and swimming. I speak of such beasts as the theories of Maxwell, Mach, Newton, Einstein, and others. Yet unless we are scientifically inclined, we avoid trying to understand them. If we accidentally happen upon one, we tend to pull up our collars, pull down our brims, and slink away. Few scientists have come along to make regular folks feel confident enough to try to comprehend such sophisticated concepts as general relativity, for example.
Enter Brian Greene, the author of The Fabric of the Cosmos: Time, Space, and the Texture of Reality. While history is studded with geniuses who have had success at defining the elusive processes that keep the universe humming, few have Brian Green's gift for making these processes transparent. Greene is adept at painting mental pictures in his own mind to flesh out the abstract concepts common to his work, and he is not afraid of casting such familiar characters as The Simpsons in his colorful translations of these concepts for us.
Much of Greene's work focuses on string theory, a hypothesis that while as yet empirically unproved, is based on math so nearly perfect that many physicists believe there must be something to it. String theory seems to stand up better in situations like "time zero" than Einstein's relativity theories, which fail when applied to the very first instant of the Big Bang
Previously, tiny particles called quarks were thought to be the basic building blocks of the universe. String theory postulates that at an even more elemental level the cosmos is built of filaments, or strings, that vibrate as various frequencies. Because of the limitations of our senses, the reality that results from accepting string theory is wildly different from the one that we experience. In Greene's bold new world, for example, there are eleven dimensions and time moves not only forward, but in all directions.
Dr. Greene, a professor of physics at Columbia University, is currently engaged in finding a way to empirically prove string theory. I decided to track him down to find out more. I caught up with him by telephone in a Denver hotel room this March.
Early in Fabric you quote Camus's book The Myth of Sisyphus: "There is only one philosophical question, and that is suicide." With this Camus seems to relegate questions of physics secondary to questions of how one lives one's life. But you disagree with Camus. Why?
Well, it's not that I fully disagree with him. I fully agree with him that there is no more important question than whether life is worth living. Where I disagree is that I think you can't assess life, you can't truly assess what it is to be part of this universe, if you don't really know what this universe is. That's why I think it's important to answer questions like how the universe came to be, what it's made of, how it evolved, what forces are at work, and what things we may be missing by virtue of relying too heavily on our everyday senses. I think those kinds of issues need to be resolved before you can even assess what it is to be part of this world.
Why should someone who is not a scientist expend the energy to try to understand concepts that are even more advanced than ideas they probably long ago filed in a corner of their brain labeled "stuff I will never really grasp anyway, so why bother?"
There was a physicist who died about fifteen years ago, Richard Feynman, and he was asked, "What do you experience when you look at a rose? Is it the same experience that the rest of us have?" And he said, "Well, I can certainly still take in the rich red color. I can still smell the wondrous aroma of the rose. But I can go further, because I can see the molecular interaction that gives rise to the color, and the interaction between the atoms that gives rise to the aroma." So the experience of the rose is richer—it's deeper, because one can actually see what it is that's making the rose appear as it does. And I think that's what physics does more generally for the world around us.
Kind of like how people enjoy football or baseball much more if they know how it works.
Yeah, exactly. If you're watching the game but don't know the rules, you might enjoy seeing the guy slide into home plate and knock the catcher over. It might be fun to watch. But if you don't really know what's going on it takes away from the experience.
Newton said time and space are rigid, whereas Einstein's theory showed time and space to be flexible and dynamic. Do you have a few similes or metaphors to help us get a handle on each view before we move into string theory?
Sure. You know, Newton's view was that space is an unchanging, static, eternal stage on which the events of the universe take place. Einstein comes along and says the stage itself can warp and curve. It's not static. It responds to whatever's walking on it. So, according to Einstein, space and time are flexible and malleable. They respond to the environment.
Your work includes much attention to the direction and measurement of time. Is it fair to say that perhaps memory is the actual sixth sense, because it's the thing we use to measure time?
I think the relationship between memory and time is a very deep and tricky one, to tell you the truth. I don't consider memory another sense. I do consider memory that which allows us to think that time flows. We all have a sense that our memory of the past was the time when a particular moment was real, and that it then receded into the past. And now we're in the present, and we can reflect back on those distant events using our memory.
I think, however, and many physicists agree, that that sense of time flowing that we all feel through memory is actually an illusion. Every moment is as real as every other. Every "now," when you say, "this is the real moment," is as real as every other "now"—and therefore all the moments are just out there. Just as every location in space is out there, I think every moment in time is out there, too.
One thing that bonds you to your colleagues and predecessors is the omnipresent desire to find one theory that explains everything. Why do humans seem to feel the need for a unified theory?
I'd say there are two reasons. One is the more aesthetic reason, which is that if we all go out and look at a dark, starry night, we see the beauty and the wonder of the universe before us, and I think we have a gut feeling that there's got to be an explanation for everything that has a beauty and an elegance and a power on par with what we actually are seeing. And a unified theory would do that. A unified theory would describe the big, the small, and everything in between using one simple idea. That's the goal.
But I need to go further, because it's not just that aesthetic reason. There are questions that we will never be able to answer until we have a unified theory. For example, we will never be able to answer the question, "How did the universe begin?", because the current laws of physics break down when you try to apply them to the very moment of creation itself. A unified theory would be one that would never break down. It would therefore allow us to address questions that today stump us.
Okay, now string theory. What is string theory? How does it differ from previous theories? And what holes in other theories does it mend?
The basic idea of string theory is pretty straightforward. It tries to answer a question that has been asked for two-and-a-half thousand years, which is, What are the smallest ingredients making up everything in the world around us? So, to be more specific, if you take a block of wood, cut that block of wood in half, cut the remaining piece in half again and keep on slicing the remaining piece into ever-smaller chunks of wood, where does the cutting stop? What is the finest, uncuttable ingredient that you get to?
Now, in our age, we know that sooner or later in this cutting process, you'll get to atoms. But we know that atoms are not the end of the line, because they can be split, they can be cut up into finer ingredients—little electrons that orbit around the central nucleus, which itself is made up of smaller particles, neutrons and protons. And even those particles, we learned in the late sixties, are made of finer ingredients known as quarks. It's sort of like a sequence of Russian dolls. Prior to string theory, it stopped with electrons and quarks. There was nothing finer. You couldn't find anything within them. String theory comes along and challenges that idea. It says that inside an electron, inside a quark, inside any particle that you've ever heard of, there is something else. It's a little filament, a little filament of vibrating energy. It kind of looks like a tiny, tiny vibrating string, which is why we call the theory "string theory." The wonderful idea is that in the same way the string on a violin can vibrate in different patterns, which our ears would hear as different musical notes, these little strings in string theory also can vibrate in different patterns. They don't produce different notes, however; they produce the different particles. So an electron is the string vibrating one way. A quark would be a string vibrating a different way. It's kind of like a music of the spheres injected into the microscopic makeup of the universe. That's the basic idea of the theory.
It's difficult to communicate these notions, so you have to come up with metaphors. To what degree do your metaphors, which in your words "all fail at some point," compromise the real essence of the science? How accurate a picture do you think your metaphors create in people's minds??
I try very hard. In fact, that's where all of the work is in writing a book of this sort. Trying to find a metaphor that works but doesn't lose the essence of the science. For instance, even the idea of a string is a metaphor in a sense, because a string is something that we're familiar with in everyday life. When we apply the word string to these entities in string theory, we are imagining that they look kind of like a string because they have one long dimension and all the other directions are very small, like an everyday string. But, of course, the strings we're familiar with in everyday life are themselves made up of atoms, which are made up of particles. Whereas if this theory is correct, the strings we're talking about in string theory are not made up of anything finer. So, you're right. Every metaphor ultimately fails, but if it gives you an intuitive picture in your mind's eye and succeeds in giving you the core of the science, then it's appropriately chosen.
Are there any aspects of string theory that don't quite mesh with observable reality? If so, how do you reconcile them?
I'd say many features of string theory don't mesh with what we observe in everyday life. For instance, the most egregious mismatch between what you see with your eyes and what string theory predicts is that string theory says there are more than three dimensions of space in the world around us. I mean, you look around the room and you can see left and right, you can see back and forth, and you can see up and down. Those are the three dimensions that we all know about and that we move through freely in day-to-day life. String theory says that there are other directions, other dimensions, in addition to those.
Eleven total dimensions. Is that what string theory predicts?
That's ten of space and one of time. You and I only see three of space and one of time.
Are there any words that can give me a hint of what dimension number eight would be like?
Well, again, you have to use an analogy, a metaphor. I freely will tell you that I cannot picture any but the three dimensions that we see with our eyes. The others I can only reason through mathematically and then use metaphors to try to get an image in my mind.
So they exist only because they must exist in order for the math to work.
Exactly. The equations of string theory say the theory does not work unless these extra dimensions are around us. The metaphor I like involves thinking about a piece of paper with two dimensions on its surface. You can call it left-right and up-down. Now imagine rolling it up into a tube. When you roll it up into a tube, it still has two dimensions on its surface and you haven't destroyed it by rolling it up. But you have changed the character of one of the dimensions. Because up/down, for instance, is now turned into a circular dimension, the clockwise/counterclockwise, direction that goes around the tube. If you make that tube really skinny by winding it up really tight, it becomes more and more difficult to see the circular dimension of the tube. You can easily see the horizontal part, the straight part, but the curled-up part becomes more difficult to see. So we think that the universe might be like that. Maybe our universe has additional dimensions that are curled up very tiny, so tiny that we can't see them with our eyes. But they nevertheless, according to the theory, would be there.
You alluded earlier to the fact that theories that predated string theory were never able to take us back to the moment of the so-called Big Bang. Does string theory take us all the way back to the very first moment? In what other ways does string theory mesh well with the Big Bang theory?
That's an important question of cutting-edge research. In fact, that is what I'm working on these days. My research program is focused on applying string theory to the Big Bang—refining the Big Bang and understanding, I hope, how the universe began according to string theory. You're right, conventional theories do break down when you try to push them all the way back to the beginning. We believe that string theory does not break down, but it still is a very complicated theory when you try to apply it to time zero itself. So far, no string theorist has succeeded in using the theory to peel back the obscuring layers and reveal what happened at the start. But the hope is that we will shortly be able to do that.
You're working on ways to test string theory empirically?
The approach that I am working on is to use astronomical observations to test string theory. By analogy the idea goes like this. I take a little balloon, and I scribble a little message on the surface of the balloon, so tiny you can't see it. But then if I blow some air into the balloon and the balloon surface stretches, the little message that I wrote will stretch out as well and become much easier to see. The same may be true of string theory and the universe. In the very beginning the universe was very small. Strings are also very small, and the strings' vibrations could have left an imprint on the environment of the young universe. But the universe was too small to be seen, and there was nobody there to see it anyway. But through 14 billion years of cosmic expansion, space stretched. And just as when you stretch the surface of the balloon it makes the little scribble easier to see, as space stretches, it may make the imprints of string theory easier to see. In other words, the imprints of string theory may be written across the sky, and all we need to do is learn how to read the message that's coming from the data that we receive through satellite-born telescopes or earth-based telescopes. There's a chance that through those kinds of observations we may see the signature of string theory.
Francis Bacon wrote in Of Atheism "A little philosophy inclineth man's mind to atheism, but depth in philosophy bringeth men's minds about to religion." As you study all this in depth, do you find yourself moving toward religion or away from religion?
It's hard to say. It really depends on what one's definition of religion is. Some people define religion in a rather abstract way, as the order and the harmony and the wonder of the universe. And from that point of view, yes, string theory is revealing great order, great harmony, and great beauty. So if you define religion in that way, then we are going toward it. But if you use a more conventional notion of religion, which involves some divine being that set all things up, I think the best we can say is that string theory has nothing to say about it one way or another. We can't ever rule a divine being out using science, because the divine being, of course, could have set it up so that we could discover what we have but see no direct imprint of the work of that divine being.
My own feeling, therefore, is that if we are revealing God's handiwork through our research, I'm happy to be part of that journey. If, on the other hand, all we're doing is revealing laws of physics that have governed the universe from the beginning until today, then I'm happy to be part of that journey, too. So whichever framework it fits into, I think the work itself is noble and interesting and very, very worthwhile.
I understand that your dad gave you the tools early on to look at the world in different ways, from different perspectives. You played a game of sorts.
We used to walk down the streets of Manhattan and one of us would fix on some unusual perspective, like the perspective of an ant on a coin that fell out of someone's pocket and was about to hit the sidewalk or the perspective of a bird in flight, just going by the buses or through an alleyway between buildings. And what we would do is we would explain what we were seeing from that point of view to the other person, and based on the description, the other person would have to guess the perspective the describer was generating. It really opened my eyes up to the various ways of looking at the world. It exercised the mind.
Sort of "I spy, with my little eyes" but you had to do it from the perspective of some other eyes.
There are a lot of very smart people out there, but I've never run into one who is able to make me understand the abstract concepts that you are able to make me understand. How do you do it?
In my own research when I'm working with equations, I never feel like I really understand what I'm doing if I'm solely relying on the mathematics for my understanding. I need to have a visual picture in my mind. I'm constantly translating from the math to some intuitive mind's-eye picture. So when it comes to writing a book of this sort, I typically make use of that visual imagery that I've built up over a long period of time in my own work. I strip away the mask and then try to develop those visual images into stories, into anecdotes, into analogies, and so forth. So it actually goes hand in hand with the way I do my own research.