LINDA WERTHEIMER, HOST:
Carlo Rovelli is an Italian theoretical physicist who heads a group studying quantum gravity in Southern France. And if that is not impressive enough, he has written a best-seller called "Seven Brief Lessons On Physics." For me, brief was the important word in that title. The seven lessons are contained in a slender volume 87 pages long.
And although the ideas contained in the little book will stretch your mind and challenge your determination to understand it, Rovelli's love of his subject and his graceful way of writing about it is more fun than you might imagine. We reach Dr. Rovelli in his hometown in Italy - in Verona. Dr. Rovelli, thank you very much for talking to us.
CARLO ROVELLI: Thank you very much for having me. It's a pleasure.
WERTHEIMER: Now, here, beginneth the first lesson. You write - (reading) in his youth, Albert Einstein spent a year loafing aimlessly. And you seem to think this was a good beginning for the greatest thinker of his age.
ROVELLI: Yes. I think it definitely - it was. I think that to be creative, people have to waste time, which doesn't mean that everybody who wastes time becomes creative, of course.
(LAUGHTER)
ROVELLI: One has to go out from the rails at some point to do something new.
WERTHEIMER: In 1905, Einstein became an overnight sensation - he was still very young - with three papers. He established that atoms really do exist. He began the discussion of quantum mechanics, and he wrote about special relativity. What is that?
ROVELLI: Special relativity is this discovery, I would say, by Einstein, that space and time are not what we thought they are, that time can pass a different speed and depend on how we move, where we are. And so that two twin brothers can meet and one is older and one is younger. All this is in this short paper written by Einstein in 1905.
WERTHEIMER: He then spent the next 10 years trying to fit his new theory of relativity with Sir Isaac Newton's theories about, among other things, gravity - why things fall. Why did that seem to Einstein to be the next great problem?
ROVELLI: Well, it came after he did special relativity because he realized that what he did was right. But it did not fit together with what we knew about gravity. So there was a problem now because - we meaning physicists or humanity - we had learned two things about the world which seemed contradictory. So he tried to find out a way to bring the two together. And that's how he came up with general relativity 10 years after, so after a long struggle.
WERTHEIMER: Now, Newton's idea about - of the universe had all of the planets spinning and then orbiting the sun. And somehow, all this was happening in a great, empty place. And one of the things that Einstein theorized must exist is something that is - a space that is not empty.
ROVELLI: Yes. Instead of this empty space, sort of where nothing happened, Einstein imagined sort of a immense, flexible thing - something that could compress, could stretch, could bend. Einstein was able to show that by thinking this way, then we understand better why things fall and why the Earth goes around the sun - better than with the force that Newton imagined.
WERTHEIMER: General relatively - you call it a beautiful theory. And you say in the paper explaining it in 1915, that Einstein made, perhaps, the greatest leap forward in thinking about physics in the physical world that has ever been made. Explain why.
ROVELLI: I realize that this may a little be, like, you know, my girlfriend is the most beautiful woman of the world because I love this theory. I like this theory (laughter). So I see it so beautifully. But it's not just me. Other great physicists have called this theory the most beautiful.
And I think that science - it can be like great literature, like art. When you get it, it's a strong emotion. It's a strong since of beauty because you suddenly learn to see the world with new eyes. It's enchanting because it's just the way space and time bend. And once one digests that, which is not immediate, of course - it takes some time to digest thing. But after all, even music - it takes some time to learn to appreciate it. Then, it's a sense of wonder. It's a sense of woe, and it's a sense of beauty.
WERTHEIMER: Thank you very much for talking to us about this.
ROVELLI: Thank you very much, Linda, for having me. It's a pleasure.
WERTHEIMER: And everybody should keep in mind, please, that there are more lessons we haven't even touched on. Dr. Rovelli's book is called "Seven Brief Lessons On Physics." Transcript provided by NPR, Copyright NPR.