Brian Greene Explains 'The Fabric Of The Cosmos'

In a new four-part television special based on his best-selling book, physicist Brian Greene takes on the nature of time and space, multiverses, and other hard-to-wrap-your-mind-around concepts in cosmology. Greene talks with guest host John Dankosky about the new series.

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JOHN DANKOSKY, HOST:

Up next, theoretical physics for the masses - well, at least for those of us who watch Public Television. In a new four-part TV series that starts next week, physicist and best-selling author Brian Greene brings extra dimensions, string theory and multiverses right into your living room. With lots of computer graphics and special effects, the four episodes tackle some of the looming questions in cosmology. Does time move in more than one direction? Are there extra dimensions that we can't see? Are there multiple universes? This isn't exactly physics 101.

While you may not understand everything about theoretical physics by the end of part four, you'll probably be able to at least dazzle your dinner guests a bit with some cosmological small talk at Thanksgiving. Joining me now to talk more about it is my guest, Brian Greene, professor of math and physics at Columbia University. He's also the author of several best-selling books on physics, including "The Fabric of the Cosmos." This new series for NOVA is based on the book. Welcome back to SCIENCE FRIDAY, Dr. Greene.

DR. BRIAN GREENE: Thank you.

DANKOSKY: So let's talk about the four parts of the series. What topics do you tackle here?

GREENE: Well, there are four shows. The first is about space, the second is about time, the third is about quantum mechanics, and the fourth is about the multiverse - the possibility of other universes.

DANKOSKY: How did you choose these four?

GREENE: Well, the show is based on my book of the same title, "The Fabric of the Cosmos," and these are four themes that I weaved together throughout the chapters of that book. And the challenge was to take some pretty esoteric, heady material and to turn it into compelling television. And the team at NOVA, people - Joe McMaster, Jonathan Sahula, Julia Cort and Paula Apsell, at the top, did a great job of doing that.

DANKOSKY: If you have questions for Brian Greene, 1-800-989-8255. That's 989-TALK. I'm sure you've got lots of big questions for him. It's a big-budget production. I mean, there's lots of animation, special effects. Did you feel like you needed all this to tell these very complex stories?

GREENE: Well, that, I think, is critical because when you're talking about space or time, what do you point the camera at? These are abstract ideas that are vital to our sense of ourselves and how the world works. Everything we do, everything we think, takes place in some region of space during some interval of time, so these are vital ideas, but they're still abstract. So what we do is, we use computer animation to take the viewer places that you can't literally go in the world around us to examine what the world would be like if time could run backwards, what the universe is like on fantastically small scales where space has vastly different properties from the space that we see in everyday life.

We take the viewer to the possibility of other universes, by showing these other universes and features about them. We can't literally go to those universes because we don't even know if they exist. It's what the math suggests might be out there, and animation only needs math in order to give us a sense of what it would be like if these ideas are true.

DANKOSKY: I'm John Dankosky, and this is SCIENCE FRIDAY from NPR. We're talking with Brian Greene, the theoretical physicist, and his brand-new series for NOVA called "The Fabric of the Cosmos." You can call us at 1-800-989-8255. That's 1-800-989-TALK. So who's the series meant for? Who's the target audience here?

GREENE: The target is very broad. When we sat down and tried to figure out what these programs would look like, we had in mind a young kid who might get excited about these ideas and go into science. We had in mind an older person who perhaps have heard about these ideas, but hasn't had the time to actually read a book on the subject but could take in a television program. So it is quite broad. And I should say when we did a similar program many years ago called "The Elegant Universe," similar in the sense of the way it was produced, the subject matter was quite different. That focused on string theory.

I was shocked that, after the series, I got letters from parents of 5-year-olds who had watched the show repeatedly. They hadn't taken in all of the ideas, but the questions the five-year-old was asking were so potent and so sensible that they definitely were understanding some of it. So I think these programs can be taken in at a variety of levels. You can allow the ideas to wash over you and take in the great computer graphics, or you can try to really grapple with, to my mind, some of the most heady ideas our species has ever contemplated.

DANKOSKY: A lot of this really has to do with the examples, the metaphors that you use. How do you arrive at some of these things, the idea that space is like a pool table, and I'm going to put down now a bowling ball on the poll table, and it's going to bend the space? How do you arrive at those, and how do you work through those to try to make sure they're things that people actually understand but are also scientifically accurate?

GREENE: Well, to me, when I do my own physics research, I'm never satisfied if when I'm doing my mathematical equations, my understanding is completely rooted in the symbols on the page. I'm always building a mental image in my own mind of what it is that I'm doing. So that, for me, is part of the process - always to have some visualization of what the equations are telling us, telling me if I'm doing my own work. When I go to write a book, I basically take those visualizations, strip away the mathematics, try to wrap up those visualizations and some side of compelling story or anecdote, and in that way, create something which communicates the ideas.

When then the team at NOVA translates it to television, we usually start with those metaphors and those visualizations, and then, they take it to the next level by using the wonders of computer animation to bring them to life in a way that words on a page simply can't do.

DANKOSKY: I have to say that as much as the computer animation is fascinating, and it takes me to places that I couldn't imagine. Some of the most interesting stuff, to me, is the personal stories of these scientists, the people who were the groundbreakers here. Maybe you can talk about - a bit about telling their stories and how you want to weave them into all of this.

GREENE: Well, when I think about science, I think about it as surely the ideas that we have come to, but it's much more than that. It is a drama of exploration, a drama of discovery and are real people who have the courage to go out into the world, into the universe, into areas that we don't understand and hopefully come out the other side with some deep intuition or understanding about how the world works. So we tell a lot of those stories. We have Peter Higgs, physicist, whose idea of a particle called the Higgs boson is now being searched for at the Large Hadron Collider in Geneva, Switzerland.

We have the story of Alan Guth, who surprisingly to himself and everybody around him, came up with a new theory of how the universe began. A theory, that in due course has suggested that there might be many big bangs, not just one big bang, giving rise to many universes. And, of course, Newton always makes an appearance in these shows, as does Einstein. So those characters are there in a big way, as well.

DANKOSKY: We're, of course, used to seeing Newton, you know, just a picture of him, but these guys, you set them up as rock stars, these real-life people.

(SOUNDBITE OF LAUGHTER)

GREENE: Well, you know, Einstein really was a rock star in his day. When he discovered the general theory of relativity, he became headline news in The New York Times.

DANKOSKY: When we come back from our break, we'll take some of your phone calls at 1-800-989-8255. We're talking with Brian Greene, professor and - of math and physics at Columbia University and, of course, author of the book "The Fabric of the Cosmos." It's a brand-new series from NOVA, and you can see that in just a little bit. We'll be back with more right after this break.

(SOUNDBITE OF MUSIC)

DANKOSKY: This is SCIENCE FRIDAY from NPR.

This is SCIENCE FRIDAY. I'm John Dankosky in for Ira. We're talking with Brian Greene, a professor of math and physics at Columbia University. He's also author of the book "The Fabric of the Cosmos." His new NOVA series is based on the book, starts next week. We want to hear a little bit from the Episode Four, on multiverses. We were talking a little bit about the people who you profiled who tell the story of physics. Let's hear the clip, and we'll talk about it afterward.

(SOUNDBITE OF TV SHOW, "THE FABRIC OF THE COSMOS")

ANDREAS ALBRECHT: I'm very uncomfortable with the multiverse. To become solid science, it's got a lot of growing up to do.

DAVID GROSS: You know, it exists in the same way that, you know, angels might exists.

STEVEN WEINBERG: We have to make our bets, and I think, right now, the multiverse is a pretty good bet.

ALAN GUTH: I think there's a good chance that the multiverse is real, and that 100 years from now, people might be convinced that it's real.

DANKOSKY: We heard from Andreas Albrecht, David Gross, Steven Weinberg and Alan Guth there. It's interesting how there's this little split, this battle. How did you set up this throughout the series because people are not exactly settled on some of the science, especially the multiverse?

GREENE: Well, the programs don't shy away from controversy because, again, one of the key things about science is while in school we learned it as a subject that's completed in the textbook. In reality, it's a living, breathing entity in which different physicists have different perspectives on where science should go, what's right and what's wrong. So the multiverse, in particular, is a very controversial subject. After all, you look around, you see one universe. There's no direct evidence for other universes. So why should you take the idea seriously?

DANKOSKY: And you're a believer in this, but leading into this, you say that some people think this could be a dead-end for science. Maybe you can explain both what that means and how you feel about it.

GREENE: Well, first, let's say I'm not a believer.

DANKOSKY: Yeah.

GREENE: I only believe in things for which there is experimental or observational support. I do think the idea of a multiverse is a powerful one that may be able to address some questions that we have not been able to address in any other way, and therefore, it's worthy of study and pursuing it and seeing where it leads. But the basic controversy is that some say if you're going to talk about realms that you can't visit, that you can't see, that you can't, in some way experiment with, you've gone beyond the bounds of science.

Science should only focus upon those things that you can absolutely experiment with or observe with. To my mind, that is too limited a perspective of what science is, because we can have mathematics that fantastically describes what we can see and then that math can go further and describe things that we can't, perhaps, yet see. We've seen this play out many times. Einstein's math told him and the world who understood the math that there should be black holes.

Einstein didn't believe that mathematics. He figured that was just too far out. But years later, we find that there are black holes. The same is true of the big bang. His math showed that the universe should have begun in this compressed state and then expanded. He didn't believe it. There's now evidence for it. So the point is, math can take us places that we haven't yet been able to see, and therefore, we can't be so close-minded, in my perspective, to completely wall ourselves off from things that we can't yet observe.

DANKOSKY: I want to get to some people who definitely want to ask you questions. Let's go to Tommy who's calling from Kentucky. Hey, Tommy, go ahead.

TOMMY: Yes. Mine is with time travel. If time slows down and theoretically stops at the speed of light, with the neutrinos that go faster than the speed of light, would time travel not be possible now?

GREENE: Well, that's why most of us don't believe the results about the neutrinos going faster than the speed of light. Because you're right, if indeed, we take Einstein's idea seriously, and the data that these recent experiments suggest showing that neutrinos go faster than the speed of light, there would be a crack in time. In a sense, we would be able to send signals to the past. So most of us believe that those experiments are probably not going to stand up to scrutiny. Even the experimenters themselves put it out as something that they want the physics community and the rest of the world to try to poke holes in to see what they did wrong.

As yet, nobody has done that, but you need independent confirmation of such a wild possibility of going faster than the speed of light. We're going to wait and see what happens. I would be thrilled if the data does stand up to scrutiny. We live for this kind of revolution in our understanding of the world. I don't think this is one of those moments.

DANKOSKY: Catherine is calling from Menlo Park, California. Hi there, Catherine. You're on with Brian Greene.

CATHERINE: Hi, Brian. How are you?

GREENE: Good. Thanks.

CATHERINE: I'm fascinated by the idea of multiple universes. When I took an astronomy class in college, they taught us that the universe is expanding, and I spent nights wondering, into what – into what is the universe expanding. And I was wondering, has there been any research or anything recently come up in terms of the physics or mathematics to indicate if the universe is expanding into a vacuum, or what might be the substance or particles that the universe would be expanding into?

GREENE: Well, in a traditional picture, where there's one universe, the idea is that when the universe expands, it's not expanding into a pre-existing realm. Because what would that realm be? It should be part of the universe, after all. Rather, the traditional idea is that space is stretching, creating the new space that it then inhabits. So that's the way in which the universe can get bigger and bigger.

In this new idea of the multiverse, however, the notion that the caller had in mind starts to come a little closer to what the math is suggesting, that there is a larger cosmos within which our universe is expanding. Our universe would be viewed as one bubble, if you will, in a big cosmic bubble bath with each bubble being universe upon universe upon universe. So there would be a larger container in some sense for our universe to expand within if this new picture is correct. I underscore if. This is, again, very hypothetical, cutting-edge ideas.

DANKOSKY: These the universes bouncing up against one another, moving farther apart as the universe expands or the space expands?

GREENE: Yes. As the space between the universes expand...

DANKOSKY: Exactly.

GREENE: ...then the universes themselves will be driven apart. However, if two universes are born very close together, something we talk about in the program, then as they expand, they can smash into each other. And if that were to happen, if our universe got hit by another, it could leave observable data in the cosmic microwave background radiation, which is a way that we might gain observational evidence for other universes.

DANKOSKY: OK. So Mark(ph) on Facebook has a question for you about some of these other universes. Since it's believed that our rules of physics may not apply to other universes, is it possible that each universe has certainly particles that do behave the same, like the quarks? Could this be the reason they act so bizarre? Wouldn't this be consistent with relativity? This is from Mark on Facebook, Brian.

GREENE: Well, the other universes in this multiverse proposal would, indeed, have other kinds of particles and would be governed by laws that, perhaps, would look different from the laws that we are familiar with here. So there'd be a whole range of possible physical features that one would encounter if you could journey from one universe to another. The weirdest thing of all - and I do consider this weird, and we discuss this in the program and many physicists give their perspective on it - the math seems to suggests that if the other universes are out there, then some of them actually do look close to ours. Some of them, in fact, have copies of us out there. You and I are having this conversation in some of these other universes way out there in this wider cosmos.

DANKOSKY: But potentially, a limitless number of copies of us in other universes. So it's not as though another me and another you are talking to another, but millions of other mes and you were talking to each other.

GREENE: Absolutely right, as strange as that sounds.

DANKOSKY: As unusual as that is. Let's go to John(ph) in Sioux City, Iowa. Hi there, John. Go ahead. You're on SCIENCE FRIDAY.

JOHN: Hey. Yeah. Oh, man. I mean, in one universe, this one, I have a question about black holes. And the other one, I have a question about the neutrino thing. So, I guess, I'll ask the black hole one. When light comes toward a black hole, is it getting sucked in or is it because space, time has been contorted so much that it's like in a fractal pattern and it just can't get out?

GREENE: Well, it's more that space is bent in such a way that the light in some sense is flowing downhill. Think of ball rolling down the side of a mountain. It rolls down to the bottom. Similarly, in the universe, if light is heading toward a black hole, the black hole warps space sort of like the hill of a mountain, and light rolls down that hill much like that ball goes down the side of the mountain. And in that way, it gets sucked in.

Now, let's me say that other question that you had, we don't have, perhaps, time to answer it now, but I will say that you should look at the World Science Festival website Wednesday night, November 2, at 10 p.m., because we're going to have a live conversation about the program that airs that night in which you and the rest of the digital audience can ask any questions that you like. And I'll do my best to answer as many as I can.

DANKOSKY: And again, this is worldsciencefestival.com, is where you can find this, right?

GREENE: Exactly.

DANKOSKY: We're talking with Brian Greene, his new "NOVA" series is coming out next month. If you want to join the conversation, it's 1-800-989-8255. That's 1-800-989-TALK. Let's go to Rick, who's calling from Palo Alto, California. Hi there, Rick.

RICK: Hey, Dr. Greene. So I – we've had a couple of fundamental open questions that, basically, all of our best efforts have failed to be able to answer, you know, uniting gravity with the other forces in a quantum theory, and more recently, dark energy and dark matter. And all this seems to suggests that we may need a radical departure from the stuff we've been doing up until now. And I wanted to get your comments on a departure that's both radical but also curious that I've heard about recently called entropic gravity with the - basically saying that gravity is not a fundamental force. I mean, maybe that could go someway to explaining some of these open questions. And what were your thoughts on that?

GREENE: Well, it is a very interesting idea, which suggests that gravity, as you say, is not as fundamental an element of the makeup of reality as we once we thought. The way I like to think about it is temperature. We all know what it means for something to be hot or cold. But the real meaning of hot and cold is not that macroscopic feeling we've learned over the course of 100 years, that if something is hot, its atoms are moving very quickly. Or if it's cold, its atoms are moving very slowly. So temperature is an emergent property of the speed of the constituent particles. And maybe the case that gravity emerges from some more fundamental underpinning in much the same as the temperature emerges from this fundamental idea of the speed particles.

And the proposals are on the table for how that might happen, it's very controversial. It stirred up a lot of excitements in the physics community. I'm not convinced yet, but it does have all of the features that many of us have thought would one day emerge in a deeper understanding, that space may not be fundamental, time may not be fundamental. Gravity, which is curves in space and time, therefore, would not be fundamental. And we are probing to see what that more fundamental structure might be. So it's an exciting time, but by no means is this idea settled.

DANKOSKY: Any of these ideas that you're talking about here, are they dependent on just – on one thing going right, going wrong? And in the research, you talked about the neutrinos, whether or not this is a finding that we can really hang our hats on here. How much of all the work that you're doing is hanging on one or two big things that we could find in the next, say, 10 or 20 years?

GREENE: Well, if we could get some new insight from the Large Hadron Collider, find some of the new particles that our theories have suggested might be out there, that would be a pivotal moment because it would really show that mathematics that we've been pursuing for decades is on the right track. It's pointing us in the direct correction. If we don't find anything at the Large Hadron Collider, that is fantastically interesting because it means that many of the ideas that we have thought were true are not, which means we have to go back to the drawing board. And again, that is great. The problem is how do you go to funding agencies and say, well, you have this big machine and it turned up nothing, and that's so exciting, we want to build another machine to pursue that further?

DANKOSKY: That's an expensive drawing board.

GREENE: It's an expensive drawing board, but it's a vital idea because it may turn out - I hope not - maybe we'll find something great at the Large Hadron Collider. But if we don't, that's a fantastically interesting result. And I hope people are at least aware of that as a potential outcome and something that should drive us forward.

DANKOSKY: I'm John Dankosky, and this is SCIENCE FRIDAY from NPR. Let's go to Paul in Orlando, Florida. Hi there, Paul. Go ahead.

PAUL: Hi. Hi, Dr. Greene. I read "Fabric of the Cosmos." It was worth every minute I spent with it.

GREENE: Thank you.

PAUL: Two things, quickly. In conversations with other colleagues, recently, we've just been talking about quantum mechanics. It's been around for over 100 years. It's provided a lot of great science, but there doesn't seem to be any great challenges to it. Are people too accepting of it or there's a lot of the - no pun intended - uncertainty about it in areas, should there be a major assault on quantum mechanics? And two, will your show address entanglement at all?

GREENE: Two good questions. So for the second one, yes, our quantum program, which is the third in this series - I guess that means November 16, if I've got that right. One of the main ideas is quantum entanglements. So we go through the whole development of Einstein, Podolsky and Rosen and John Bell and all that great stuff, which suggests, from the experiment, that something you do in one location can immediately affect something in another location. Again, one of these crazy ideas but comes out of the math quantum mechanics.

And for your first question, yes, I think there are some gaping holes in quantum mechanics. Not everybody agrees with that. We need to understand how the active measurement affects the system. This is still up in the air after a century, and we're working on it and, hopefully, more and more people will.

DANKOSKY: So what exactly does a theoretical physicist do all day? In the second of SCIENCE FRIDAY's Desktop Diaries series, Brian Greene takes us into his home office for a tour of his tidy workspace using his desk mainly for calculations, often executed with pencil and paper, a tradition that dates back to his childhood when his father would give him 30-digit by 30-digit multiplication problems to work out.

Here to tell us more about the tour is our multimedia editor, Flora Lichtman. Hi, Flora.

FLORA LICHTMAN, BYLINE: Hi, John.

DANKOSKY: So this is interesting. You got a chance to visit Brian in his workspace.

LICHTMAN: Yes, and everybody else has this chance, too. If you've been loving this interview, you can go to our website and see where Brian works. And, you know, the premise of this series is that our desk trinkets maybe reveal a little about us. And in Brian Greene's case, there were very few desk trinkets. It was a very clean space. So actually, I wanted to ask you, what do you think it - you know, do you think it means anything about you that you work in such a clean area?

GREENE: Well, it means I've certainly changed because I think I've mentioned awhile ago, when I was in college, I was very, very sloppy. My room was voted the sloppiest on campus, and it's in the college yearbook. I mean, I walk around and I'd heard like little Chinese mustard packets squirting under my feet. But I found that I couldn't think clearly if I was surrounded by a clutter. If I've got a file of stuff that I haven't looked at for a few months, I realized I should throw it away because I'm never going to look at it. And I just think more clearly in a clean space.

LICHTMAN: Yeah. It's not piles of papers like you see in some of these scientists' workspace.

DANKOSKY: Well, actually, in the shows, in the "NOVA" shows, some of the scientists have some pretty - very messy workspaces, let's just say.

GREENE: Yes. Saul Perlmutter, who just won the Nobel Prize, he has a pretty cluttered space you'll see in the show.

(SOUNDBITE OF LAUGHTER)

DANKOSKY: We see clips of your dad in this video, who was a performer. Do you feel like your following in his footsteps now, getting out on the green screen, getting out on stage?

(SOUNDBITE OF LAUGHTER)

GREENE: Vaguely. You know, my dad was a performer. He was a singer and quite a showman. And I guess, maybe some of it rubbed off in some way.

DANKOSKY: I'm wondering if this idea of using a pencil and paper is still vital to what you do. I mean, is it important to have that pencil there to (unintelligible)?

GREENE: For me, it is. I mean, I can imagine a generation or two from now, people won't know what a pencil is, and it will just change the way they do things. For instance, when I write books, I do them purely on a computer. I cannot write a book on a piece of paper. When it comes to calculations, I have to do them on a piece of paper.

LICHTMAN: So no iPad?

GREENE: Not yet, but I will.

(SOUNDBITE OF LAUGHTER)

DANKOSKY: Well, we've just about run out of time. So I'd like to thank my guest, Brian Greene, professor of math and physics at Columbia University, author of the book "The Fabric of the Cosmos." His new "NOVA" series based on the book starts next week. Brian, thanks so much for joining us once again.

GREENE: My pleasure.

DANKOSKY: And thanks also to Flora Lichtman, multimedia editor for SCIENCE FRIDAY. You can check out this video, right?

LICHTMAN: Go to our website, sciencefriday.com, to see Brian Greene's desk.

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