SCOTT SIMON, host:

Stanislaw Ulam would've been 100 years old yesterday, and even if you don't recognize the name immediately, you're probably familiar with his work. Stanislaw Ulam was a mathematician. He helped design the hydrogen bomb. He was a leading figure in the Manhattan Project at Los Alamos, New Mexico, the top-secret project to develop the atom bombs that ended World War II. And later with Edward Teller, he helped work out the design of the thermonuclear weapons that were at the height of the Cold War.

We turn now to our math guy, Keith Devlin of Stanford University. He joins us now from member station KGNU in Boulder, Colorado. Keith, thanks so much for being with us.

Professor KEITH DEVLIN (Stanford University): Hi, Scott. Thanks for having me on again.

SIMON: How does a mathematician wind up on the atom bomb project?

Prof. DEVLIN: First, of all, the very idea of an atom bomb came from theoretical mathematical calculations. They then knew this thing would work before anyone would - had been able to build it or even try to build it. John von Neumann, a very famous mathematician, one of the guys who began the computer industry in the United States, or the ideas of computers, and it was von Neumann that actually recruited Ulam as one of several mathematicians to go to Los Alamos to work on the Manhattan Project.

SIMON: And as I understand it, at one point he corrected Edward Teller?

Prof. DEVLIN: This was in the - 1943, 1944. Teller was already starting working on the idea of an H-bomb. He'd got a design that he'd worked out. Ulam looks at it and says, no, that's actually not going to work, and then came up with an improved way of building the thing. Teller agreed and then thought about it. And in fact Teller then came up with an even better design. So the final design of the H-bomb is actually known in the business as the Teller-Ulam or the Ulam-Teller H-bomb.

SIMON: What other things did Stanislaw Ulam work on that made him proud about his life and career?

Prof. DEVLIN: First of all, in his early career, when he was growing up in Poland, he worked in number theory, ergodic theory, algebraic topology, discrete mathematics, did a lot of varying clever mathematics. But it was really only after he came to the States and started thinking about issues to do with the real world that his genius really came to the fore. He was one of these people, almost like Einstein, that could think of things in different ways. One of the things he did when he was working on the atom bomb was that they were faced with solving mathematical problems with the very crude computers that were just being built.

They couldn't solve them, so he invented, along with a few other people, what's now known as the Monte Carlo method, which is essentially a method of gambling or guessing what the answer to a solution could be and then using mathematics to deduce on the basis of those guesses what the real answer actually is. It's a very clever, powerful method that's now used all over the world.

But I think the most intriguing thing he came up with was something called Nuclear Pulse Propulsion. And it's a way of building spacecraft. What you would do, you would have this large cabin where the people would be. Then there'd be a large steel plate connected to the cabin by some very, very large shock absorbers. And then what you would do to get this thing off the ground and send it all the way to Mars, say, you would detonate a large number of small atom bombs behind the plate. So the thrust from the atom bombs would accelerate this thing out into space and then at some considerable distance.

SIMON: And explain to me something called, I gather, the singularity event.

Prof. DEVLIN: Yeah, there are actually two or three singularities. One of them is the one that Ulam came up with in a conversation in 1958 with John von Neumann. And they observed that the rate of change of technology was heating up. Things were changing faster and faster. Eventually the rate of change of technology would reach a stage that it was too fast for human beings to keep up with it. And the question is what happens when the change is so fast that a human being literally, literally couldn't keep up with it? Society would clearly change in ways that we can't understand. And the mathematical term for an event like that is it's a singularity. [POST-BROADCAST CORRECTION: Stanislaw Ulam wrote about the conversation in 1958, but Von Neumann died in February, 1957.]

SIMON: Could we have passed that point already? We just don't know it yet?

Prof. DEVLIN: I don't know. I mean it literally is one of these tantalizing questions where we really don't know how to answer it. And I don't think we actually can answer the question you've just given.

SIMON: Keith Devlin, mathematics professor at Stanford University and executive director of that university's H-STAR Institute.

Keith, thanks so much.

Prof. DEVLIN: Okay. My pleasure, Scott.

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