3 Astronomers Win Nobel Physics Prize

Three U.S.-born scientists won the Nobel Prize in physics on Tuesday for their studies of exploding stars that revealed that the expansion of the universe is accelerating. The three will share $1.5 million.

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DAVID GREENE, Host:

This is MORNING EDITION from NPR News I'm David Greene.

LYNN NEARY, Host:

And I'm Lynn Neary. The Nobel Prize for physics goes to three astronomers this year. They discovered that the expansion of our universe is speeding up. That completely unexpected discovery suggests that empty space is actually filled with some mysterious form of energy called dark energy and that dark energy is pushing our universe apart. Joining us to talk about the winners and their science is NPR's Richard Harris.

Good morning, Richard. Good to have you with us.

RICHARD HARRIS: Good morning.

NEARY: That sounds so fascinating. Tell us something about these astronomers who won the price today.

HARRIS: Well, half of the prize goes to Saul Perlmutter, who is at the Lawrence Berkeley Lab at the University of California at Berkeley. And the other half is shared by Adam Riess who is now at the Space Telescope Science Institute and Johns Hopkins University in Baltimore; and he shares his half with Brian Schmidt who was born in Missoula, Montana, but now works at the Australian National Observatory.

So, they're all young. They're all still pretty young, in the prime of their careers. Perlmutter is 52; Schmidt is 44 and Adam Reese's 42. And, as I mentioned, Schmidt and Reese actually worked together on one team and Perlmutter headed up a second team. And the big breakthrough, the big papers they both published independently came out in 1998.

And they independently came to the same rather remarkable conclusion, which is that the universe is not only expanding - which people had been measuring actually since the 1920s - but the expansion is actually speeding up.

NEARY: Now, how do they figure that out and what exactly does that mean?

HARRIS: Well, they figured it out by studying some very distant stars called supernovas. They measured how fast the universe was expanding long ago by looking at these very distant supernovas and they found that the universe had been actually expanding faster in the last five billion years ago, than it had been before that time. That means the expansion is getting faster. It's accelerating, which is totally bizarre

Now until these teams made this discovery, we had a reasonably tidy view of the universe. It started about 13 billion years ago. You remember the Big Bang? Well, you don't personally remember it. But...

(SOUNDBITE OF LAUGHTER)

HARRIS: ...the thought was that all the matter sort of came out a fact huge Big Bang and some expansion that followed that. And then basically it was coasting through the universe ever after. And the question until these guys came along was: Is it just going to coast forever and gradually gravity would strong enough and pull it all back together for Big Crunch, or what?

But it turns out it wasn't just expanding out, just sort of coasting out. It's speeding up. It's moving away faster and faster and faster.

NEARY: Well, what's causing that? What's causing that acceleration?

HARRIS: Well, you can get the next Nobel Prize if a few can answer that question, actually.

(SOUNDBITE OF LAUGHTER)

HARRIS: That is the big question. And with these two independent observations, these scientists are confident that it is happening. But exactly why it's happening is a real mystery. And that's actually what makes this such an exciting discovery, is that it's something fundamentally new and different about our universe, and obviously Nobel-caliber work here.

But what's causing that acceleration is still hotly debated. One major idea is that empty space isn't actually completely empty. It's filled with some serious energy which has been nicknamed dark energy. And that energy is somehow working against gravity to push the universe apart faster and faster.

NEARY: Oh, sounds kind of scary, actually.

(SOUNDBITE OF LAUGHTER)

NEARY: But this discovery, they published this discovery about supernovas back in 1998. So, at that time, did people understand, did they realize it was a really big deal?

HARRIS: Yeah, it's one of those things where you look at it and you say wow, this is totally amazing. And the world of science woke up and it was page one stories around all the world. And it was really one of those key moments where you said these guys are onto something fantastic. Assuming it's correct, and with two independent results, it seemed pretty likely it was correct.

It's sort of equivalent in some ways to discovering this weird microwave hum that was discovered many years ago in the universe, which was the major clue that actually a Big Bang had occurred. Or even the earlier discovery from the 1920s that the universe is expanding.

NEARY: Well, Richard, I want to assure you I'm never going to get the Nobel Prize in physics. But thanks for being with us this morning.

(SOUNDBITE OF LAUGHTER)

HARRIS: My pleasure.

NEARY: NPR's Richard Harris.

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