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From NPR News, this is ALL THINGS CONSIDERED. I'm Michele Norris.
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And I'm Robert Siegel.
There are scientists who think that there maybe more than one universe. There's ours, of course. But these scientists imagine others, and if you think that's strange, NPR's Robert Krulwich reports that some are proposing experiments that will allow people to create a universe.
ROBERT KRULWICH: So, you're a professor of both mathematics and of physics at Columbia University. You're the author of The Elegant Universe, right?
Dr. BRIAN GREENE (Columbia University): That's it.
KRULWICH: And Brian Greene, you are telling me that it is possible - it's not even crazy to think that one day a person might be able to create a universe. So we could have, you say, a man made universe?
Dr. GREENE: So it turns out that it's not a crazy question to ask. It's a question that's susceptible to mathematical analysis. And analyses seem to indicate that it's tough to build your own universe, but nobody has really been able to say that it's impossible and some have even suggested hypothetical ways that you might actually do it compatible with the laws of physics as we currently understand them.
KRULWICH: Okay. I'm game. Let's just try to do this that you and I - let's try to build a universe.
(Soundbite of music)
You don't start this big, you can't, says Brian.
Dr. GREENE: Well, if you want a manageable way of building a universe, what you want to be able to do is build something pretty small. You don't want to have to construct a universe that's hundred of millions of light years across because that's a construction job that's just really beyond the pail, can't even think about doing that. You in some sense want to build something small.
KRULWICH: How small can you begin? Can you -
Dr. GREENE: You can calculate that the nugget that we believe perhaps gave rise to our universe was about roughly, you know, 10 to the minus 26 centimeters across. Ten to the minus 26 centimeters? That's small.
KRULWICH: That's very small, smaller than a single atom. So if our universe started as a subatomic spec, how much did it weigh?
Dr. GREENE: Ten pounds, and from -
KRULWICH: Ten pounds? That's a very little thing to weigh 10 pounds.
Dr. GREENE: Yes. So it's very dense. But on the flip side, even though 10 pounds may seem like a lot for something so small to weigh. And it is. Because it means it's very dense. You wouldn't really think intuitively that you could build a whole universe from 10 pounds of stuff. I think you would think that to build a whole universe, I'm talking about a universe with stars and galaxies -our universe. Hundreds of billions of stars and hundreds of billions of galaxies, you think it'd be more than 10 pounds of this stuff.
KRULWICH: Okay. So if our universe with all its stars, all its galaxies sprang from a tiny atomic sized 10-pound seed, how does a person build a seed like that?
Dr. GREENE: It's not easy to do. And people have struggled to figure out ways that might work.
KRULWICH: One way that might work says Brian Greene is to start the quest called a mini black hole.
Dr. GREENE: Now, we can all imagine the big black holes. Black holes are these gigantic hugely massive astrophysical objects where if you get too close you can't escape. You fall down the funnel. But it turns out that black holes can be quite small. They don't have to be big.
KRULWICH: They don't?
Dr. GREENE: No, not at all.
KRULWICH: It would, says Brian, be entirely possible to take, for example, an ordinary common watermelon, and put it inside some incredibly powerful squeezing machine - it's not yet been invented - that squeezes so fiercely that the watermelon would become denser and denser and so dense that at some point predicted by Einstein, the watermelon would change state and become a mini black hole.
(Soundbite of object being squeezed)
Dr. GREENE: That's it.
KRULWICH: Now, I know we made the sounds up there but theoretically is this a real possibility?
Dr. GREENE: Oh, yeah. Absolutely. You give me any object and if I squeeze it, sufficiently small, then according to the classical laws of general relativity, if you make it small enough, it will be a tiny black hole. Now -
KRULWICH: A grape? Can you make a grape into a black hole?
Dr. GREENE: Absolutely.
KRULWICH: Can you make a raspberry into a black hole? Can you make a blueberry into a black hole?
Dr. GREENE: Seriously, there's nothing that you can give me that I couldn't turn into a black hole by squeezing it sufficiently small. And this is unfamiliar because black holes have this reputation, as we're saying, big gargantuan mass of things, but they don't have to be.
KRULWICH: In fact, in the next decade, he says, teams of scientists will try to manufacture mini black holes.
Dr. GREENE: And this is not just hypothetical. There's a new machine being built in Geneva, Switzerland, right now, called the Large Hedron Collider. And one of the things that may happen at the Large Hedron Collider is the creation of microscopic black holes and the collision between protons and protons. These will be tiny black holes but black holes nonetheless.
KRULWICH: Okay. But because these are such tiny little black holes, remember we're trying to build a universe here -
Dr. GREENE: Small things are not a universe -
Dr. GREENE: - so it has to expand.
KRULWICH: Right. So how does a tiny black hole expand?
Dr. GREENE: It then explodes -
(Soundbite of explosion)
- roughly speaking.
(Soundbite of explosion)
KRULWICH: Now this is the universe I was waiting for. So, how do you do this? Obviously you've inserted something or you change something to alter the physics of the little black hole, right?
Dr. GREENE: Yeah. Exactly. And as physics has to do with a strange feature of gravity that none of us have ever experienced but the math shows us is true and observations at space seem to confirm. And that is as gravity can actually be not only attractive. It cannot not only pull things together, it can also be repulsive. It can push things apart.
KRULWICH: Push things apart. So you put something into the little black hole that made it push outwards because everything on the inside is repulsed. I'm not quite sure what that means - repulsed.
Dr. GREENE: It's what you think. It's up there, would have a repulsion. They will, instead of wanting to come together, they would be driven to move apart.
KRULWICH: And this force exists in nature?
Dr. GREENE: The repulsive side, there's actually direct observational support for it.
KRULWICH: So it is there and if you can learn to release this repulsive force, theoretically, you could hit a ball into the air. And, instead of coming back down to earth, instead the space between the ball and the earth would suddenly be filled with repulsive energy. Pushing out, pushing on the two sharp elbows, pushing the ball further and further and further away from earth as the space between gets bigger and bigger and bigger. So this force, what it does? It creates space, so much space that it can turn a little black hole into a universe.
(Soundbite of music)
Dr. GREENE: Because the repulsive side of gravity is so powerful, that it actually injects energy from gravity itself into the expanding space. So from that point of view, all you need is the seed and then gravity takes over and does the rest of the work.
KRULWICH: And right now, there are scientists at Ben-Gurion University in Israel, Yamagata University in Japan, Stanford University in California, who are trying to manufacture first a seed - a mini black hole. And into that seed, one day they hope to place the trigger to release this repulsive force and so create, unbelievable as it may seem, the first man made universe.
(Soundbite of music)
Dr. GREENE: If you can build this little seed, this little nugget in just the right way, it will on it's own, start to expand, grow, faster and faster and faster beginning tiny and sprouting into a gigantic universe.
(Soundbite of music)
KRULWICH: And truly, why do something like this? Brian says for a scientist, if you can do this safely, the technical and intellectual challenges are so fascinating.
Dr. GREENE: I may have to say, I think I might have a little trouble resisting this possibility just because it's so curious. This idea that through your volitional act in your kitchen sink, you are creating a universe that will give rise perhaps to things like we see in the world around us.
KRULWICH: But maybe the biggest surprise here is that Professor Green, who's a world class physicist, and Andre Linde Standford at the Wukisakai in Japan take the notion of a man made seed spawning a universe and instead of thinking this is a completely crazy idea, they seem to think it's plausible.
Dr. GREENE: That's the question. And so far the answer seems to be no. That there is nothing it says this is impossible.
KRULWICH: Now, that doesn't mean they'll ever do it. But the fact that they're imagining it and making plans to try it one day that's the biggest surprise of all.
Robert Krulwich, NPR News in New York.
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