JUANA SUMMERS, HOST:
All summer long, NPR's Short Wave podcast has been exploring our changing universe. And today, we end the series with a bang - the Big Bang theory for how our universe began - you know, the one Stephen Hawking popularized.
SUMMERS: All summer long, NPR's Short Wave podcast has been exploring our changing universe. And today, we end the series with a bang - the Big Bang theory for how our universe began - you know, the one Stephen Hawking popularized.
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STEPHEN HAWKING: One view of the universe prevailed.
SUMMERS: But here's the thing, even though that definition is pretty common, it's not really how many scientists talk about the Big Bang these days. NPR's Regina Barber has more.
SUMMERS: But here's the thing, even though that definition is pretty common, it's not really how many scientists talk about the Big Bang these days. NPR's Regina Barber has more.
REGINA BARBER, BYLINE: When I was a kid, I pictured the Big Bang as a big explosion, a moment in time. But cosmologists now think of the Big Bang as an era of time, lasting hundreds of thousands of years. This change can all be traced back to an accidental eavesdropping session that happened roughly 60 years ago...
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BARBER: ...With a giant horn-shaped antenna in New Jersey, overseen by two radio astronomers, Arno Penzias and Robert Wilson.
RENEE HLOZEK: You see photos of them, and they're standing next to this giant antenna, arms wide open, looking at the sky. And one of the things that they noticed is it didn't matter where they pointed this detector in the sky, they had a residual noise and kind of a background.
BARBER: Renee Hlozek is an observational cosmologist, someone who studies how the universe began.
HLOZEK: They spent a lot of time trying to figure out what it could be, including the bird poop that had been collected...
BARBER: (Laughter).
HLOZEK: ...In the detectors. They try to calibrate all their instruments.
BARBER: They thought it was New York...
HLOZEK: Yeah.
BARBER: ...Maybe.
HLOZEK: Anywhere in the sky, you'd see this.
BARBER: But what they accidentally found was ancient light created in the Big Bang era. We call this light the cosmic microwave background.
HLOZEK: So it's this light from about 400,000 years after the beginning of the Big Bang in this Big Bang era.
BARBER: Yeah.
HLOZEK: A nice thought that I like to say to people is if you get on the subway in a city and you sit down, and you feel that the seat is warm, you know that someone was there before you, right? And that's sort of the same thing. We look out everywhere in the sky, and we see this microwave light just everywhere. It's that, you know, hot subway seat but all over the sky.
BARBER: But the cosmic microwave background is not the same temperature everywhere. There are tiny fluctuations, certain spots that are hotter than others. And this provides a clue about the origins of galaxies. Now cosmologists like Renee are creating heat maps, sketching out how our early universe began. But theoretical physicist Chanda Prescod-Weinstein says all these discoveries build on one another.
CHANDA PRESCOD-WEINSTEIN: There are times when we come up with ideas that we think we can't test or that we don't know how to test, and that later it becomes clear that we actually can test them and that it is a matter of time and human ingenuity.
BARBER: That's one of my favorite things about, like, science and being a scientist. And you know this, Chanda and Renee, like, it's all about this constant discovery of, like, new things.
PRESCOD-WEINSTEIN: Right. I think my hope as a scientist is not that I will be the one to make the great discovery or idea, and I think that's a very outdated way of thinking about what science is about. My hope is, is that the work that I do now helps to continuously lay the foundation for us to push the boundaries of our understanding forward, whether it's this generation or a generation, like, seven generations from now that works out some of the problems that I've committed my life to.
BARBER: Bringing us one step closer to understanding how our universe and we began. Regina Barber, NPR News.
(SOUNDBITE OF SLVR SONG, "BACK N FORTH") Transcript provided by NPR, Copyright NPR.
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