Picking Up Cosmic Vibrations

A pivotal week in Corey Gray's life began with a powwow in Alberta and culminated with a piece of history: The first-ever detection https://www.ligo.caltech.edu/page/press-release-gw170817of gravitational waves from the collision of two neutron stars. Corey was on the graveyard shift at LIGO, the Laser Interferometer Gravitational-Wave Observatory in Hanford, Washington, when the historic signal came. This episode, Corey talks about the discovery, the "Gravitational Wave Grass Dance Special" that preceded it and how he got his Blackfoot name. (encore) See pcm.adswizz.com https://pcm.adswizz.com for information about our collection and use of personal data for sponsorship and to manage your podcast sponsorship preferences. NPR Privacy Policy https://www.npr.org/about-npr/179878450/privacy-policy

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• 0:00Speaker 00

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• 0:16Regina Barber?

  You're listening to Short Wave from NPR.

• 0:20Speaker 02

  So, oki, t'ne tapi, netaniku, makuyuhusuku, ki Corey Gray. Hi, I was just giving a greeting in Blackfoot, and I gave my Blackfoot name, which is Wolf's Path, and also my name, Corey Gray.

• 0:37Regina Barber?

  I'm Regina Barber, and I've known Cory for years. We've connected at conferences as fellow scientists of color.

• 0:43Speaker 02

  I am a senior operations specialist at the LIGO Hanford Observatory in Eastern Washington State.

• 0:51Regina Barber?

  LIGO measures ripples in space called gravitational waves.

• 0:55Speaker 02

  Yeah, so what are gravitational waves? For, I guess the main thing, I would say that all of this comes from Albert Einstein. It comes from his General Theory of Relativity in 1915. Basically, gravity is just how masses bend the space around them. And that's the idea of what gravity is in general relativity. If you take this mass and accelerate it in space or spacetime, those accelerations vibrate spacetime. And those vibrations, those wiggles in spacetime, are what gravitational waves are.

• 1:26Regina Barber?

  LIGO stands for Laser Inferometer Gravitational Observatory, and Cory has worked there since the beginning. He waited 17 years to see evidence of two black holes colliding into each other, the first direct evidence of gravitational waves, 100 years almost to the day after Einstein's prediction.

• 1:47Speaker 02

  Yeah, you can't write a script to make it better than what actually happened.

• 1:50Regina Barber?

  Wow, yeah, tell me more.

• 1:52Speaker 02

  My shift was from 4:00 PM to midnight. And so I handed off to the operator who's doing the graveyard shift, starting at midnight. And I always joked that around, by the time I got home and was putting my head on my pillow and closing my eyes, that's about when the signal passed through the Earth, passed through me, and it passed through all of us. I'm looking at my arm because I have a tattoo. It's September 14, 2015.

• 2:16Regina Barber?

  Tell us a little bit more about like how, what this meant to you that it meant so much you got a tattoo.

• 2:21Speaker 02

  I don't have any kids, but that's what I would think it would feel like to have a kid, to like to see the sonogram or see the, the, an image of your child for the first time. And that's how it felt to me. And when I saw it, I knew that I would have it on my body. And right around Einstein's birthday or Pi Day, that's when I went to a tattoo parlor in Old San Juan, Puerto Rico, and asked them to Google GW150914. And they did that and they found the image and they put it on my body.

• 2:48Regina Barber?

  Oh my God. Okay. For our listeners, can you describe what that waveform looks like?

• 2:54Speaker 02

  Yeah, I mean, it just basically looks like a wiggly, two wiggly lines. One line is red, and that's the data from the detector here in Washington State. And the other line, wiggly line, is blue. That's the data from the detector in Livingston, Louisiana.

• 3:11Regina Barber?

  Then, a couple of years later, the first detection of two neutron stars colliding occurred. And the week leading up to that event connected aspects of Corey's life. Today on the show, we're talking vibrations through space and the instruments and people that detect them. I'm Regina Barber, and you're listening to Short Wave from NPR.

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• 5:04Regina Barber?

  Gravitational waves are really elusive. And Corey Gray says that when the detection happens, there's a little signature in the data that can be processed into a sound.

• 5:14Speaker 02

  The merger detections, we call it a chirp.

• 5:19Speaker 02

  And it's basically, if you look at what the signal looks like, what you're seeing and hearing is the frequency increasing and the amplitude increasing. So some of them are going to be higher in frequency, some are going to be lower. Like, I think for our first detection, it's much lower. So it's a little like, but for this first detection, we had a loud signal, which was capturing the final fraction of a second of two black holes smashing into each other after dancing together, orbiting each other for millions of years. And that's what we need because these signals are so, so tiny because they happen from so far away, so long ago. And we need the strongest ones to be able to see with our instruments, which are the most sensitive instruments

• 6:03Speaker 02

  that have ever been made by humanity. And that's what we need. Strong sources, most sensitive instruments, to see these really faint, ghost-like signals that are passing through us all the time.

• 6:14Regina Barber?

  So tell us about those instruments. Like, what is LIGO? How does a laser interferometer measurement work?

• 6:23Speaker 02

  So we use an optical setup called an interferometer. So we have a light source, which is a laser. And we take this laser and we shoot it at a piece of glass called a beam splitter. And so half of the light goes right through this piece of glass. And then the other half of the light is reflected off of another surface of this glass. And you have these two twin waves of light that are born and then split from that beam splitter. They go down four kilometer long arms in an L shape. So one's going straight and the other one's going orthogonal to that, so 90 degrees in another direction.

• 6:58Regina Barber?

  Okay, so you have these two identical beams.

• 7:00Speaker 02

  Yes.

• 7:01Regina Barber?

  Going down 2.5 miles.

• 7:03Speaker 02

  Yeah, and then those waves of light hit those mirrors. And then they come back to the beam splitter and then they interfere with each other. We wait for anything to move those mirrors that are four kilometers away down each arm. So any type of length change over that four kilometers, we can hopefully see at a sensor back here at the corner of that L of our detector.

• 7:31Regina Barber?

  And you're saying that like you're looking for this length change in these like 2.5 miles. And this gravitational wave that's bending space time actually changes. And I like to say change is reality, but change is that length, right? It's changing space.

• 7:50Speaker 02

  Definitely, yes.

• 7:51Regina Barber?

  And that's mind blowing. And I've heard you say that you're basically using a very advanced ruler that can measure these miniscule changes in length. Can you explain that like a bit further?

• 8:05Speaker 02

  Over four kilometers, we can resolve length changes on the order of 1,000 times smaller than the diameter of a proton. That's the sensitivity that we have for these LIGO detectors.

• 8:17Regina Barber?

  All right, so now, now we're gonna go in the wayback machine. We're gonna go in a time machine. And you're gonna tell me the story of how you came to LIGO.

• 8:25Speaker 02

  So when I was a kid, I always had an inkling towards the sciences.

• 8:31Regina Barber?

  Me too, me too.

• 8:32Speaker 02

  I received bachelor's of science degrees in physics and applied mathematics at Humboldt State University. And then, and then eventually saw a job announcement in the LA Times for a job up in Eastern Washington State.

• 8:46Regina Barber?

  You were there at the start of this construction. And you waited 17 years. And I remember back in 2001, somebody came from LIGO to my university in Washington State. And they're like, any day now, we're gonna detect something. Any day now. And it was 14 years later. But, um, so this first detection happens, and it's a huge deal. And, and being there must have felt amazing.

• 9:12Speaker 02

  When I woke up the next morning after the detection was recorded, that's when you, that's when it hit me for the first time. That's when I know that we're officially connected forever to Albert Einstein. We're a part of history.

• 9:26Regina Barber?

  LIGO's goal was to announce the first detection in as many languages as possible. Corey instantly thought of his mother, Sharon Yellowfly. He recruited her to translate news of this breakthrough into the Blackfoot language.

• 9:41Speaker 02

  My mom did an amazing job. My mom grew up with Blackfoot as her first language. But for some technical words, there weren't Blackfoot words. So my mom had to invent new Blackfoot words.

• 9:55Speaker 04

  ... Einstein. Ich weiß nicht. LIGO.

• 10:02Speaker 02

  It, it just, it sounds like poetry.

• 10:04Regina Barber?

  Do you think that there was some contribution to science that you and your mother were doing that like is overlooked? Or has been overlooked for? Hundreds of years.

• 10:15Speaker 02

  Yeah, I mean, this is kind of a path that I'm kind of learning on my own now because, I mean, being an indigenous physicist or indigenous scientist was kind of, for me, a lonely path. But I think with my mom's work, it kind of taught me a few things. It taught me that our language is important enough to translate astrophysics. And it also raised my awareness or my curiosity in looking into indigenous sciences. For a lot of indigenous peoples, there is that connection to the sky and to space. I mean, my Blackfoot name that I

• 10:55Speaker 02

  just received a couple of months ago is related to the Blackfoot story for the Milky Way.

• 11:01Regina Barber?

  Can you tell us that story?

• 11:03Speaker 02

  As far as what I know is, I think it's basically, I think it was a winter or sometime when the people were struggling, living. They're having a rough time living through winters, getting food. They were starving. And they were approached by these group of people. They were actually wolves that were in the form of humans. And they kind of imparted their knowledge to these suffering people to kind of give them ways to survive, like what sort of animals to hunt. And then they went away. And then the story is that every

• 11:41Speaker 02

  spring in the sky, this light that you would see up above you at night is the path of these wolves that visited our people.

• 11:55Regina Barber?

  Oh, I can kind of understand why you would get that name because you are sharing this knowledge.

• 12:01Speaker 02

  Oh dang, I'd never even thought of that. That's so cool, Gina. Wow.

• 12:05Regina Barber?

  You're welcome.

• 12:08Regina Barber?

  Which brings us to the powwow you had just attended up in Alberta. Right before you came back to work for that groundbreaking discovery. Can you take us to that powwow?

• 12:18Speaker 02

  This particular powwow, we actually had an event that my cousin and I both had thought up. We called it a gravitational wave grass dance special. And so grass dance, grass dance is a style of dance in powwows. And for people who don't know, powwows are kind of social events, like intertribal social events for native peoples in the kind of the United States and Canada. And so when I think of that, kind of after the fact, when I, when I was there for this event, we had 17 dancers out there. And I just think of all that power from their prayers, from their, their, their dance for this gravitational wave grass dance special that occurred that night.

• 13:02Speaker 02

  I just think there's power in that.

• 13:04Regina Barber?

  And it led right up to this huge moment in your career. Did you feel any connection there?

• 13:10Speaker 02

  So, I mean, that's one of the things that I obviously made a connection to that week prior, or the week and a half prior, because after the grass dance special on August 10th, I had to basically drive all the way home for graveyard shifts. And that was my first time sitting in the chair to ever have that happen. That first week, that first shift of mine coming back from Sixica, that's when our first binary neutron star was recorded by LIGO. And so, and then that one's just a completely different type of detection compared to all of the other ones prior to that, because instead of two black holes, we recorded two neutron stars crashing to each other.

• 13:51Regina Barber?

  Okay, Corey, so what's next for LIGO?

• 13:53Speaker 02

  We'll have an improved detector. And what's going to happen? We're going to have a much more sensitive machine. So we'll be able to reach further out into the universe. But I'm always holding out for what's going to be, what can be new, like what's going to be new? Supernovas that are close to us? If we could be online when one of those occurred, that would be a first for us.

• 14:16Regina Barber?

  That'd be so cool.

• 14:17Speaker 02

  But I think my favorite one would be something that would be a complete surprise to theorists and to all of us that we hadn't thought of.

• 14:23Regina Barber?

  Do you feel that there's like, the Blackfoot way of understanding the universe? It can teach scientists, like the kind of- What do I want to say, Western science as well?

• 14:33Speaker 02

  Yeah, I mean, when I sat back and thought about what is general relativity, and it does make me think about or hearken back to indigenous science. That connection that indigenous people have to the world around them is such a prevalent concept, and you see it in all these other cultures. And so that's what I think about when I think of Einstein and his general theory of relativity, because that's what he's kind of explaining, how all masses are connected to the spacetime around them.

• 15:11Regina Barber?

  Corey Gray, thank you so much for coming to talk to us and telling us all about your work at LIGO.

• 15:18Speaker 02

  And thank you, Gina. It was a pleasure.

• 15:21Regina Barber?

  This episode was produced by Devin Schwartz, edited by Gabriel Spitzer, and fact-checked by Ubi Levine. I'm Regina Barber. Thanks for listening to Short Wave from NPR.

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