Leon Lederman Interview (page: 4 / 8) Nobel Prize in Physics	Print Interview

Could you say in lay person's terms, what happened as a result of that Nobel prize winning discovery?

Leon Lederman: You can't take it by itself. You have to say it's part of a pattern. It's part of a search for an understanding of how the world really works.

Metaphor is useful in this. Suppose Johnny was given an assignment by his teacher:

Get the Flash Player to see this video. Leon Lederman: "What makes a library work? What are the common, simplest elements that make up a library?" Let's take that. A library is a complex thing. My metaphor would be, just to warn you ahead of time, the library is like the universe. So Johnny goes says, "What a nuisance." He goes to the library and says, "It's obvious. A library is made of books. Books make a library." But, then he remembers the teacher said, "What's the simplest ingredients?" He sees a lot of books: fat books, skinny books, tall books, short books, profound books, stupid books, the library has all the books. So he says, "It must be something simpler than books." And he looks inside books. Books are made of chapters, chapters are made of paragraphs, paragraphs are made of sentences -- not getting anywhere, really -- and then he sees the sentences are made of words. And then he remembers that at the entrance to the library, there's a big, fat collection of words. Presumably that collection of words, which is called a dictionary, if you put those words together in different ways, you make all the books. You need a set of rules, right? What are the rules by which you put the words together? Let's call the rules "grammar." So with that dictionary and the rules, which we call "grammar," we can make all the books in the library. And, then Johnny says, "Now, I got it." Except that he begins to worry because he remembers "simple." The teacher said it has to be simple, and the dictionary book with all the words is very thick, right? This is a real big, well to-do library. So he says, "What else is there? Ah, I got it! Every one of those words is made up of only 26 letters. So if I have 26 letters, and a new set of rules -- we'll call those rules spelling -- my 26 letters and spelling will make all the words in the dictionary, and all the words in the dictionary will make all the books in the library."

Get the Flash Player to see this video. Leon Lederman: So he's very happy, he goes home, starts writing it up, when his baby sister comes and says, "What're you doing?" He doesn't want to be annoyed, but he knows he's going to get punished if he doesn't treat his sister with a certain amount of respect, so he explains the assignment. And he says, "Look, it's 26 letters. Just imagine just how simple it is: 26 letters, spelling and grammar make all the books in the library, and she says, "You're stupid," and now he's nervous because when she says that, he knows there's something. She's very bright. He says, "What do you mean?" She says, "All you need is a zero and a one." He realized, of course. Why shall the child show us? Children these days grow up with digital toys in their cribs, and they know about zeros and ones before the older people. For grown-ups who don't know about zeros and ones, you can use Morse code, which is a dot and a dash. But a zero and a one, or a dot and a dash, with a new rule, maybe Morse code or a computer algorithm, you can make all 26 letters. So now the story is, the library universe can be explained by just two things, a zero and a one, put together by a certain set of rules which make the letters, which make the words, which make the sentences and the paragraphs and the books in the library. So the neutrino turns out to be, we think, one of those ingredients. It turns out, we can't get away with only two. Oh, to end the story, if the zero and the one can't be taken apart, so far, we've taken everything apart, the books into chapters and paragraphs and words and letters, and now we have a zero and a one. If the zero and the one can't be taken apart, you've got the bottom line. You've got the primordial building blocks of the library.

Get the Flash Player to see this video. Leon Lederman: The question is "what works for the universe," and it turns out there are certain basic particles. We now believe that, by a consensus, which doesn't mean it's right, it just means that it's our current belief that we've gotten the zeros and the ones for the universe in which we live, and the neutrino is one of those crucial particles. So, that's the significance. It doesn't help us cure the common cold. It doesn't help us gain economic advantage over our competitors. It's pure knowledge. It's understanding the universe in which we live, a subject which really started science. It was when the ancients looked up at the sky, and saw the seasons, and looked at the variety of materials, air, water, fire, earth, and so on, they said, "This is all very complicated." And then they said, "There must be something simple behind it all." It's that old, Greek notion of simplicity that has developed the subject of science. We've been on that road from that early 2500 year ago idea to the present time in learning how the universe works. You if say, "It's expensive," and it is expensive. The counter-argument is that in the course of following that road, we changed the way people live because we invented all kinds of things. Mechanics and electricity and lasers, and all the things that fuel modern society came out of that quest for how the library works.

A writer in Scientific American brought up a very interesting practical ramification in relation to your work. He asks, "Do neutrinos have mass? If they do, could the gravitational attraction of myriad neutrinos keep the universe from expanding forever and becoming a cold, dark void?" That would be nice.

Get the Flash Player to see this video. Leon Lederman: Yes. Neutrinos may have an interesting role to play in the greater scheme of things. But, again to answer that question for the kid who's curious, you have to say, "Why? What has this got to do with the universe?" And, in fact, it has a lot to do with the universe. It turns out, if we want to understand the universe, which means the stars and the galaxies, and all the great big things, we have to know the small things. That's what we call "the inner space-outer space connection." We have to know about the small things in order to understand how the big things work. That particular example is a very fascinating one. We know that the universe is expanding as if there were an explosion roughly 15 billion years ago. It's called, the Big Bang. In that explosion, all the matter in the universe spewed out and space and time, radiated. Got bigger and bigger and bigger. Now the question is, will this continue forever? Or will it slow down because gravity is an attractive force? Gravity says "Come back, come back!" How strong is gravity compared to the initial explosive force? That's an issue. That depends. It's an experimental issue. We can find this out. It depends on how much mass there is. The more mass, the more gravity. If we add up all the mass, count all the stars we can see with the most powerful telescopes, we estimate how much mass they have, we can calculate whether we have enough mass to slow up the expansion. When we do, we find we don't have nearly enough mass. But, on the other hand, there are the neutrinos. We know they're there because we know enough about the big explosion to know that it spewed enormous number of neutrinos around. The neutrinos themselves would have no impact on the expansion if they have zero mass. On the other hand, if it's not zero, but teensy-weensy, but not zero, just a small amount, then the neutrinos might act to break the expansion, slow it down. So, the issue then after we discovered the neutrino, was to see whether in fact, since the 1960s, we now know that in the universe, in nature, there are three neutrinos. Part of the zeros and ones is there are three different kinds of neutrinos. We don't know very much about the masses. If they have a small mass, they can act to change the future of the universe. Those are experiments one can do.

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