Brian Greene talks physics

Q: You'll be talking about "The Fabric of the Cosmos: Space, Time and the Texture of Reality." So you're keeping the scope narrow.

A: Yeah. Just a few key ideas about the cosmos.

Q: Share a highlight or two?

A: Well, I'm going to go through the major developments in the long search to understand how the universe began. And I'm going to touch on some of the real high points in this journey including the Big Bang theory, something called "inflationary cosmology," and then I'll discuss how some of the speculative ideas at the edge of modern physics are suggesting a very bizarre universe, but it may be the one we inhabit.

Q: Woody Allen said reality is the only place you can get a good steak. Is this in question now?

A: (Laughs.) Well, as a vegan I certainly take exception to that particular metaphor.

Q: If I'm to believe you about time travel, I won't be able to go back and kill Glenn Beck's parents before they conceive. You're crushing a lot of dreams, bub.

A: Sorry about that, but it's sort of an amazing thing that Einstein taught us over 100 years ago, that a certain kind of time travel is actually part of physics as we understand it — that is time travel to the future. And that to me is totally amazing. Executing time travel to the future requires space ships that can go near the speed of light or travel near black holes — little details that we at the moment certainly can't surmount. But time travel to the future is allowed by the laws of physics. However, time travel to the past — which is the one that people really I think have more of a fascination with — that one seems to be locked out by physics.

Q: You consulted on the time-travel movie "Déjà Vu." My question: How hot is Denzel Washington?

A: I never met him. Sorry about that.

Q: Bearing in mind that most of us can't figure out how to do an e-mail attachment, please explain String Theory — briefly.

A: Sure, I can try. String Theory tries to tell us what the basic ingredients making up stuff in the world is. And we certainly have learned that if you look at any piece of matter sufficiently closely you find molecules, which are made of atoms, which are made of electrons orbiting a nucleus with neutrons and protons, and the neutrons and protons themselves are made of finer particles called quarks. It's like a sequence of Russian dolls. Inside every particle there's something else.

Now conventional ideas stop with electrons and quarks. They're little tiny dots with nothing inside. String Theory comes along and says, well hang on, actually there may be another layer. Inside the electron and inside the quark there may be something else. In fact, it suggests that the something else is a little tiny filament that looks like a string, vibrating away. And the string inside the electron vibrates in one pattern and the string inside a quark vibrates in a different pattern, and that way everything is a manifestation of these little vibrating strings.

Q: Since there's no experiment to prove strings exist ...

A: Yet! Yet! Yet!

Q: ... how do we know you guys aren't just making stuff up?

A: Well, we certainly at this moment are unable to do an experiment that can prove the theory right or wrong, but that is a temporary state of affairs — we hope, we think. Because otherwise we're not doing science. And there's a chance that this new machine being built in Geneva, the large Hadron Collider, big atom smasher, in the next few years there's at least a chance that it could begin to see the fingerprints of at least some of the ideas that we're working on.

Q: You talk about alternate dimensions that are like slices in a loaf of bread. My question: Can you score me some of that primo weed?

A: (Laughs.) What would you like on it?

Q: Could you just explain what you're talking about?

A: Well the idea is that String Theory teaches us — again, only if the theory is correct, which I emphasize we don't know yet — but if it is correct, it tells us that there are more dimensions than the three that we can directly see. We all see left-right, back-forth and up-down. This theory claims that there are others. And one way of picturing them is to think of the universe as if it's a giant loaf of bread where everything that we have long thought to be the universe is simply one slice in this big cosmic loaf. And the other slices are other regions of the cosmos that we can't see because our vision, our sight, is limited to our piece of bread, but these other slices according to String Theory could be there. And those other slices are like alternate universes. They may be like our universe, they may be very different. And they can be floating right nearby.

Q: For the sake of my self-esteem, tell me one household chore that you can't figure out how to do.

A: I can't figure out how to put the ironing board out without making a horrendous screech.