SCOTT DETROW, HOST:
Ten years ago this month, gravitational waves were first detected on planet Earth. Now, gravitational waves had been something that scientists had thought existed going back to Albert Einstein. His theory was that collisions between very large objects in space, like stars or black holes, produced invisible ripples - ripples that are so powerful, they could disrupt space-time. And for a long time, it was just that - a theory - until finally, after decades of debate, on September 14, 2015, the very first wave was detected as evidenced by this little sound.
(SOUNDBITE OF GRAVITATIONAL WAVE)
DETROW: And that bloop (ph) confirmed there had been interference in space-time. I am here with host Lulu Miller, who talks about these gravitational waves on Radiolab's "Terrestrials," a podcast for kids and adults. Hi, Lulu.
LULU MILLER: Hey, hey. I am so excited to be talking to you about this phenomenon in the universe that I barely understand. But I do understand a little bit more now that I've interviewed very smart scientists about it.
DETROW: That's journalism - right? - to understand something just enough to put it on the radio.
MILLER: That is what we do.
DETROW: So one of these smart scientists that your episode centers around - a leading scientist who worked on gravitational waves - her name is Wanda Diaz-Merced. Tell us about Wanda.
MILLER: So Wanda is amazing. She's so fun to talk to. She was born in Puerto Rico in the 1970s. And when she was a kid, she went to the island of Culebra, where there was really no light pollution. That's what really got her interested in space. And she talks about it better. So I'll just play a little clip.
(SOUNDBITE OF PODCAST, "TERRESTRIALS")
WANDA DIAZ-MERCED: I looked up, and I saw so many stars. It was like someone took a brush, dipped it in white paint and then just splashed the brush on a very black...
MILLER: Wow.
DIAZ-MERCED: ...Background.
MILLER: Like, it was just more stars than you'd ever seen.
DIAZ-MERCED: Si. And for some reason, I felt closer to them.
DETROW: You go from such an evocative description of something she sees to the fact that she eventually loses her eyesight and becomes blind. But what's interesting is that that didn't stop her from wanting to study the stars, right? She keeps studying astronomy in college. What happens after that?
MILLER: Yeah, I mean, and not without real challenges. Like, she talked about some of her professors and other classmates would actually laugh at her. They'd say, you can't be a blind astronomer. But she keeps going, and then her friend, Emilio, one day, handed her this object that would change her life. And I will - I'll play that clip, too.
(SOUNDBITE OF PODCAST, "TERRESTRIALS")
DIAZ-MERCED: It's a radio receiver that receive the waves that are emitted by an antenna, like the radio station.
MILLER: Only this radio - it was able to hear things beyond the Earth.
(SOUNDBITE OF RHYTHMIC SWOOSHING SOUND)
DIAZ-MERCED: It was capable of detecting things like, for example, emissions from the sun and also the galactic background.
MILLER: Wait, so, like, you're hearing that in real time?
(SOUNDBITE OF RHYTHMIC SWOOSHING SOUND)
DIAZ-MERCED: Yes.
MILLER: (Gasping).
DIAZ-MERCED: I was hearing it.
(SOUNDBITE OF RHYTHMIC SWOOSHING SOUND)
MILLER: Wanda played us the sound of a bit of energy leaving Jupiter.
DIAZ-MERCED: And when I heard that, I thought there is space for me in this science.
(SOUNDBITE OF MUSIC)
DETROW: So what was that space?
MILLER: Yeah, so she learned it wasn't only the sun emitting energy that, you know, with the right instruments, you could hear. It was also pulsars and black holes and clouds of plasma. And, you know, by analyzing those sounds, their pulses, etc., astronomers can get clues to their age, composition, structure, motion. But then another thing is a newer thing called sonification, which is basically taking really complex visual data and turning it into sound - into music, really, that lets you consider patterns in totally different ways than the eyes. And so she uses both of these techniques to keep deciphering the information pouring down from space.
DETROW: And that brings us back to the bloop you heard at the beginning.
MILLER: (Laughter) Yes - to the bloop.
(SOUNDBITE OF GRAVITATIONAL WAVE)
DETROW: Like, that's a big bloop because we're talking about space-time - this huge, big, theoretical idea, but that it was just the theory. How did her work intersect with that big discovery, the detection of those waves?
MILLER: Yeah. So flashback, you know, 10 years ago, it's September 2015, and Wanda, at that time, was working at the Harvard Smithsonian Center. And she remembers hearing that - you know, the news that the gravitational wave observatory here in the States, LIGO, had detected actual interference. She remembers just whispering and her heart fluttering because, like, they were there. She had always believed in them, and in a way, she identified with them because there had been so much time in her life that people hadn't believed in her. And here was...
DETROW: Yeah.
MILLER: ...This thing that was invisible, and sighted people - a lot of them weren't sure it was there. But it was there, and now we knew for sure.
DETROW: What is Wanda studying these days?
MILLER: So yeah, she's really a leader in this field of sonification. She shares her work, and it's also now being used by all kinds of other fields that have complex datasets like oceanography, geology, medical research. And so it's really opening a new door to human understanding, a new way of identifying patterns that the eyes miss. And she's worked with all kinds of places - with NASA, with a gravitational wave observatory in Pisa, Italy - again, just training more scientists how to listen to space.
DETROW: Happy Gravitational Wave Detection Day.
MILLER: (Laughter) Happy Gravitational Wave Detection Day.
DETROW: That is Lulu Miller, host of "Terrestrials," an occasionally musical podcast about the strangeness of life here on Earth. You can hear the full episode about Wanda and gravitational waves on the Radiolab for Kids feed.
Oh wait, and Lulu, one more question, actually. How does Wanda actually detect these waves?
MILLER: Well, it is a very cool machine with long arms that uses a complicated set of mirrors and lasers to detect if there has been interference in space-time, meaning the machine is obviously called the...
(SOUNDBITE OF ARCHIVED RECORDING)
DIAZ-MERCED: Interferometer.
MILLER: Interferometer.
(SOUNDBITE OF MUSIC)
DETROW: The interferometer. Transcript provided by NPR, Copyright NPR.
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