One of the most ambitious and exciting theories ever proposed one that may be the long-sought Theory of Everything that eluded even Einstein gets a masterful, lavishly computer-animated explanation from bestselling author-physicist Brian Greene when NOVA presents the nuts, bolts and sometimes outright nuttiness of string theory. "The Elegant Universe," a groundbreaking three-hour miniseries, airs on PBS 45 & 49 Tuesdays, October 28-November 4, 8 pm each night.
Also known as superstring theory, the startling idea proposes that the fundamental ingredients of nature are inconceivably tiny strings of energy, whose different modes of vibration underlie everything that happens in the universe. The theory successfully unites the laws of the large general relativity and the laws of the small quantum mechanics breaking a conceptual logjam that has frustrated the worlds smartest scientists for nearly a century.
Greene is professor of physics and mathematics at Columbia University, where he is one of the worlds foremost string theorists. He is also an unusually adept science explainer, whose book The Elegant Universe became a runaway bestseller and whose popular lectures pulse with string-like energy, not to mention infectious humor.
"If anyone can make string theory accessible, Greene can," marvels New York Magazine. Small wonder, since the Harvard- and Oxford-graduated physicist has studied acting and has performed in college musicals and community theater. Working with the Emerson String Quartet, he has also created a live presentation that merges physics and music; the program has drawn sell-out crowds and is now being developed for Lincoln Centers 2005 season.
On NOVA, Greene brings these wide-ranging talents to bear on a theory that is notoriously difficult to grasp, yet one that is exciting to both scientists and laypeople alike.
If string theory proves correct, the visible universe obscures a reality that is far more rich and subtle than anyone ever imagined a universe with numerous hidden dimensions, a universe in which the fabric of space can rip and tear, a universe that may be but one of many parallel universes ceaselessly popping in and out of existence throughout eternity.
And these are just some of the astounding implications of strings!
Program one, "Einsteins Dream" (10/28, 8:00 p.m. ET), introduces string theory and shows how modern physics composed of two theories that are ferociously incompatible reached its schizophrenic impasse: one theory, known as general relativity, is fantastically successful in describing big things like stars and galaxies; another, called quantum mechanics, is equally successful in describing small things like atoms and subatomic particles. Albert Einstein, the inventor of general relativity, dreamed of finding a single theory that would embrace all of natures laws. But in his quest for the so-called unified theory, Einstein came up empty-handed, and the conflict between general relativity and quantum mechanics has stymied all whove followed. That is, until the discovery of string theory.
"Strings the Thing" (10/28, 9:00 p.m. ET) opens with a whimsical movie scene in which the history of the universe runs backwards to the Big Bang, the moment at which general relativity and quantum mechanics both come into play therefore the point at which the conventional model of reality breaks down. Then its string theory to the rescue as Greene describes the serendipitous steps that led from a forgotten 200-year-old mathematical formula to the first glimmerings of strings quivering strands of energy whose different vibrations give rise to quarks, electrons, photons and all other elementary particles. Strings are truly tiny smaller than an atom by the same factor that a tree is smaller than the entire universe. But, as Greene explains, it is possible for the first time ever to combine the laws of the large and the laws of the small into a proposal for a single, harmonious Theory of Everything.
One of the most peculiar aspects of strings is that they require more than the three familiar dimensions of space plus one of time. In fact, string theory calls for at least 10 dimensions in order that its rather abstruse mathematics remain consistent. Greene demonstrates how these extra dimensions can be folded up in plain sight without anyone noticing. Its like an electrical power cable seen from afar, he explains. To a person, the cable looks like a one-dimensional line. But to an ant crawling on the cable, it has an extra, circular dimension its circumference which people cant see from a distance.
On a much smaller scale, strings may vibrate in and around extra dimensions that are so tiny that people are completely unaware of them, even though, the theory claims, they play a vital part in determining why the world has the properties it does. But even with its many theoretical successes, by the 1990s physicists realized that strings suffered from a pernicious flaw an embarrassment of riches: there were five different versions of the theory, each totally out-of-sync with the others. If theres only one universe, shouldnt there be one Theory of Everything?
"Welcome to the 11th Dimension" (11/4, 8:00 p.m.) shows how in 1995 Edward Witten of Princetons Institute for Advanced Study, aided by others, revolutionized string theory by successfully uniting the five different versions into a single theory that is cryptically named "M-theory," a development that required a total of 11 dimensions.
Ten & 11 & whos counting? But the new 11th dimension is different from all the others, since it implies that strings can come in higher dimensional shapes called membranes, or "branes" for short. These possess truly science-fiction-like qualities, since in principle they can be as large as the universe. A brane can even be a universe a parallel universe and we may be living in one right now.
Branes may also explain why gravity is the weakest force, requiring all the matter in the entire earth to produce a measly one g. According to this idea, gravity may be far more potent, but most of its strength is leaking into a parallel universe.
Witten has described string theory as "a part of 21st-century physics that fell by chance into the 20th century." In fact, the theory is so far ahead of experimental technique that there is as yet no way to verify whether strings are real or a figment of some very creative imaginations.
But scientists at the CERN atom-smasher on the French-Swiss border are working to test one of the predictions of string theory. Scheduled to run later in this decade, this experiment may take an important step in showing that string theory is not just a crazy idea, but crazy reality.
Brian Greene Talks About Strings, Extra Dimensions, Parallel Universes, And His Cameo Role in A Hollywood Movie
In 1999 physicist Brain Greenes engrossing book on string theory, The Elegant Universe, hit the stores and became a surprise bestseller, proving that there is a voracious audience for the latest findings from those, like Greene, who probe the most fundamental questions about the physical universe.
"Elegance," says Greene, is a theoretical physicists ideal, "the goal to reduce a complex-looking universe to a very elegant and simple universe." And string theory, he believes, "is the biggest step in that direction that weve been able to take."
Greene recently answered questions about strings and other matters from his office at Columbia University, where he is professor of physics and mathematics.
Q: In junior high we all learned about atoms. Could you give us your junior-high explanation of string theory?
A: Sure. In most junior high texts today, you might have, say, a picture of an apple. When you look very closely at the apple you see it is composed of various molecules that are made of atomswhich themselves are made of electrons around neutrons and protons. Thats where the junior high picture of today would stop. String theory would simply add one more layer to that story. It would say that those particleselectrons and neutrons and protonsare made of smaller things. Now, if it were a really good junior high book, it would have said that neutrons and protons are made of quarks, because that has been known since the late sixties. String theory would say electrons and quarks are themselves made of something else. And that something else is a little filament of vibrating energy that looks like a string. Just like the strings on a violin can vibrate in different patterns, which your ears hear as different musical tones, the little strings in string theory can also vibrate in different patterns. You dont hear them as music; you see them as different particles. So an electron is simply a string vibrating in one pattern. And a quark is a string vibrating in a different pattern. And any other particle that youve ever heard of is a string vibrating in yet another pattern. Everything comes down to the notes that these little strings can play.
Q: How did you get involved in the field?
A: Ive had a deep fascination with gravity, since I was in college. Gravity has always been the most mysterious of natures forces. The big problem that was apparent when I was an undergraduate, and for years way before then, was how to merge gravity, the force that is most relevant for the big stuff in the universe, stars, galaxies, and so forth; and quantum mechanics, which deals with forces on the microscopic scale. So in 1984, when I began graduate school at Oxford and rumors spread that this new approach called string theory had done it, that absolutely seemed to be the theory to think about.
Q: Were you in on the ground floor?
A: Oh, most definitely. There were only a handful of people who had worked on the theory prior to 1984, which meant that the playing field was rather level.
Q: There are some theories, like the theory of evolution, that are based on one simple idea and everything flows out of it. Is string theory like that?
A: Not yet. That is the missing piece of the theorys structure, at the moment. You can say that string theory flows out of the quest for unificationto put all known laws into one theoretical package, as opposed to having laws that work here, and laws that work there, but dont really have much to do with each other. If thats your goal, string theory appears to be what youve been looking for. But if youre to say, OK, great, its a unified theory. But why does it work? What is that one core idea from which the theory inevitably follows? That I wouldnt be able to tell you, because thats what were still looking for.
Q: You seem very comfortable on camera and Ive read that youve acted in amateur productions. Could you tell us about that side of your life?
A: My dad was a vocal coach and he was constantly working with people in the arts. So there was a theatrical quality in the air when I was growing up. I never went that direction myself, but when I got to college I became more interested and ended up doing some pretty bad theater. And then when I was in Cornell, I took some acting classes just because I really enjoyed them. There was a call for auditions for Betrayal, a Harold Pinter play. I got a part in that, and that was actually pretty good.
Q: Was it one of Pinters absurdist dramas?
A: In a way. The most odd thing about it was it happened backward in time. So the first scene that you see is actually the last moment of the play. And then, scene-by-scene it devolves. It goes further and further back in time so by the end of the play, youre at the beginning of the interaction that set everything in motion. Its very interesting.
Q: It sounds like some of the weird effects that show up in string theory.
A: Definitely.
Q: Tell us about your cameo role in the 2000 movie Frequency.
A: I play myself, sort of. The film has a time warp element, where this father and son are communicating with a ham radio across thirty years of time. The director, Greg Hoblit [Hill Street Blues, L.A. Law] was searching for visual clues to hint at what is going on before it becomes totally apparent. He also wanted some potential scientific basis, which of course, there isnt really. He spoke to me, and one of the visual clues that he decided on was to have a television set in the fathers living room and in the sons living room, on which I am being interviewed by Dick Cavett, both in 1969 and in 1999. So in 1969 I looked thirty or so, and in 1999 I was made to look sixty. In 1969 we were talking about the state of physics then. And in 1999 we were talking about where things had gotten in the thirty years since we last spoke.
Q: Did you write your own dialogue?
A: By and large. I sat down with the writer, and we kicked around some of the ideas that he thought would be good to get across in the interview. But on camera Dick Cavett improvised these sometimes off-the-wall questions, which were kind of fun. So I just did it off the cuff, knowing that there were certain things that would be good to cover, like the possibility of extra dimensions and parallel universes.
Q: Did you advise them on the plot?
A: From the get-go I told them, look, its not really possible; so dont look for a scientific justification. The best you can do is set up a set of rules within which the movie is going to operate quasi-scientifically. And dont break those rules! In other words, let the viewer feel like, OK, if I buy into that, then all of the rest makes sense. The basic rules were that you had these two parallel universes that got out of sync, so that the universe of the father, thirty years in the past, got jolted thirty years forward, relative to his sons, and in that way they were cross-communicating across universes. That was the working idea.
Q: In the past there has been a spate of books that connect particle physics to ideas like Zen Buddhism. How do you feel about people who take science into these novel realms?
A: My own feeling is that I would rather give the viewer or the reader or the listener the facts, and if they choose to make connections to these other realms, thats great. I dont understand those connections, and I dont know if theyre really there. Maybe they are, or maybe theyre not. I just dont know. I dont see myself as the person to draw those connections. I see myself as the person to explain what weve rigorously accomplished in our pursuit of these scientific ideas. And then the person is free to take that information and do whatever they enjoy or feel is worthwhile to do with it.
Q: Is that the aim of this NOVA series?
A: Yes, basically. Id like people to watch and leave with a fairly good sense of where weve gotten in physics in the last couple hundred years. Then I want them to feel like theyve got a rough grasp of some of the bizarre but cutting edge developments that are emerging today. And last, they should have a good time with it. Those are really the three main goals of the series.
Q: Whats it like for you to see the abstract ideas from your book [The Elegant Universe] come alive on TV with all its visual richness?
A: Its very exciting. Something can be communicated in an understandable way in words, but then its up to the reader to form a mental picture. To see the stuff animated in full-color graphics and really come to life in front of you is wonderfully exciting.
Q: For the fans of your book, which came out in 1999, does NOVA offer an update on the latest developments?
A: Definitely. The first two hours of the series cover the bulk of whats in the book, and the third hour takes up material in the last couple chapters but then rapidly moves on to things that have occurred since.
Q: What are some of the ideas in the third hour?
A: We realized in the late 1990s that string theory is not just a theory of strings; it also has other ingredients that go by the name of membranes, or branes, for short. A recent idea is that these branes may not be small; they might be big, and in fact we might be living on one right now. Our universethe space that we see around usmight actually be a brane, which is one of the ingredients of the modern incarnation of string theory, which is called M-theory.
Q: Can you give us your junior-high explanation of M-theory?
A: I dont even have to be technical to describe what it is. Prior to 1995 there were five distinct formulations of string theory. They all agreed in some ways, but when you looked at them in detail they just looked plain different. This was not a good thing, because sometimes more is less. You dont want five different theories for one single universe. We didnt like that. But what could we do? Then, post 1995, breakthroughs established that the five are really five different ways of talking about one single theory thats called M-theory. Were still trying to figure out what that meta-unified M-theory is. We know a lot about it, but were still piecing it together. What has pretty much been established is that the five string theories are really not different; theyre all the same. Theyre just phrased in different languages.
Q: One of the hardest to picture aspects of string theory is that it involves extra dimensions. Could you talk about that?
A: There are two key issues here. The first is, why extra dimensions? Thats the more difficult question, because it comes from the mathematics of the theory. The math simply goes haywire unless the universe has more than the three space dimensions we know about. The other issue is how to picture what it would mean for our universe to have extra dimensions. My favorite example is to take a piece of paper. Flat on that sheet are two dimensions: left/right and up/down. If you roll up it into a tube, it still has two dimensions, but you have dramatically changed the character of one of them. For instance, you might still have left/right undisturbed, but up/down, is now rolled up into a circular dimension. If you roll that tube more and more tightly, at some point it gets so tiny that you cant even see that theres a circular cross section at all. The tube would, in principle, just look like a line. Now, of course we know that deeply tucked in to that line theres another curled up dimension that we simply have difficulty seeing. If you make it as thin as a blood capillary or very thin steel wire, then you cant even see the thickness. And that might be not only a feature of things like a tube of paper, but of the universe itself. There might be big, easy-to-see, obvious dimensions; those are the three dimensions in which we live. And just like the tube has an additional curled up dimension, maybe our universe has additional curled up dimensions too.
Q: The current string theory calls for eleven dimensions, right?
A: Thats right. Theres one dimension of time, and then there are ten space dimensions. Three of these are the ones that weve known about for thousands of years, and the theory claims that there are seven more that we dont know about, at least not through our senses.
Q: Is there something special about our three?
A: Well, theyre three among eleven, but theyre potentially special in that we believe theyre likely bigger than the other ones, and were aware of the big ones. But other than that, theyre all cut from the same fabric; theyre all the same stuff.
Q: You have a real knack for coming up with analogies that help non-scientists get a grasp on your work. Do you find these analogies helpful in your own thinking about these problems?
A: I feel that I dont truly grasp something if my understanding is based on the technical equations alone. The equations are critical to being able to do the research, but to have a gut feel for whats going on, I need to have a picture. So in my own work I try to come up with these metaphors and analogies that will cut to the heart of whatever it is that Im working on. For instance, when I think about extra dimensions, the analogy of rolling up a tube of paper is something I use all the time. Of course, when I do the calculations I use the equations. But when I try to reason visually, those kinds of pictures are there.
Q: Theres a funny scene in the first hour where youre trying to explain relativity to a dogthe point being that maybe our attempts to understand the fundamental nature of reality are as doomed as a dog trying to understand Einstein. Do you think this might be the case?
A: Its quite possible that we are in the position of the dog and that our brains simply dont have the power to grasp the fundamental laws of the universe. That is definitely possible. But the only thing that we can really go by is experience. And so far, every single time when we thought we might have hit the wall; we might not be able to solve this problem; we might not be able to figure it out, every time, so far, we have been able to push through. We have, through thought and experiment, been able to make the necessary progress. So that gives me some hope that even though no doubt we have limited intellectual capacity, perhaps we are well in tune with the universe and will be able to sort out the deep laws.
Q: What development in string theory has surprised you most?
A: Early on in Oxford, I wasnt even aware that the theory needed more dimensions, so thats a huge break with intuition. Overall, though, the most far-reaching lesson and the one that has yet to be fully realized is that space and time may be merely secondary concepts that rest on finer, more subtle, more elemental organizing principles that we are still in the midst of trying to discover. That to me is the most wonderful idea of them all. How can you think about the world around you without thinking about space and thinking about time? It seems downright impossible. But these ideas seem to be telling us that, in reality, the universe itself is fundamentally space-less and timeless. And space and time just emerge from its more elemental ingredients. Thats amazing.
Q: Any thoughts on how Einstein would have reacted to this?
A: I like to think he would have been extraordinarily impressed and excited about these developments, since they make use of a geometrical approach to the universe that was his whole philosophy. And moreover, they realize a unified theory of all forces and all interactions, which was his dream. So it fulfills his dream with more or less his own philosophy. I think he would love it.
Q: Why do you think string theory has captured the public imagination the way it has?
A: I think that in one form or another were all searching for explanation, were all searching for meaning; were all searching for something deeper than mere experience. And when people encounter the ideas of string theory and realize that not only does it give a unified theory, but it paints a picture of reality thats different from everyday experience, I think many people find it very exciting. To realize that theres much more to the world than what we see; theres much more to the world than what we directly experience, thats deeply moving.
Q: Did it surprise you to see your book became a bestseller?
A: I was definitely surprised. It was the kind of thing that I thought could happen, because Ive been going out giving lectures to general audiences for a long time, and I could always sense this strong undercurrent of interest. People would want to read more. So I thought, maybe there was a small a chance that the book would tap into that enthusiasm. But of course there are many wonderful books that dont catch on as well. A lot of times its just luck.
Q: Youve been called the new Carl Sagan. How do you feel about that?
A: Its extremely flattering to be placed in the same sentence with Carl Sagan. When I was growing up Carl Sagan was an idol. I thought it was amazing what he was doing, and to come anywhere close to doing what he did for science is a wonderful thing, if thats true.
Q: How do your peer feel about it?
A: Its hard to say. The ones who have spoken to me about it have been generally very enthusiastic. If you think about it, these are ideas that many of us have worked on for decades. And for a long time the ideas really didnt get wide circulation; it was only the string theory community who knew about the advances and the exciting work that was going on. So I think many people in the field are gratified that the work that was behind closed doors is now receiving much wider attention.
Q: What does a theoretical physicist such as yourself do in his spare time?
A: These days not much, Im afraid. When Im involved in so many projects its hard to do much. In the past I used to do a lot of sportsjudo mainly and a good deal of running.
Q: Any reading?
A: I love reading Graham Greene and Kurt Vonnegut. Those are probably my two recent favorites. I really liked Vonneguts Sirens of Titan and Slaughterhouse Five; and Graham Greenes The End of the Affair.
Q: Ive read that you follow a vegan diet. How did that happen?
A: I gave up meat at nine years old, but I was just an ordinary vegetarian for many years. Then five or six years ago I went to an animal sanctuary in upstate New York and learned a lot about the dairy industry and how animals are treated. A couple of days later I just gave up all animal products completely. Its a personal thing. I dont proselytize about it, but that doesnt mean I dont feel strongly about it on a societal scale.
