Gravity’s Cosmic Symphony with Kelly Holley-Bockelmann

Could LISA detect primordial black holes or gravitational waves from the Big Bang? Neil deGrasse Tyson and co-host Chuck Nice explore LISA and the future of gravitational wave astronomy with astrophysicist Kelly Holley-Bockelmann.

Speaker names marked ? are inferred from speaking time and the show’s known hosts — they are not voice-verified.

• 0:00Neil deGrasse Tyson?

  Chuck, if you give an astrophysicist a cookie, they'll ask for more. You, we weren't happy with LIGO.

• 0:06Chuck Nice?

  No.

• 0:07Neil deGrasse Tyson?

  There's more black holes to detect.

• 0:09Chuck Nice?

  Yeah, yeah, exactly. We got now we got now we got Lisa, which, you know, I have to I have to say a better name than LIGO.

• 0:18Neil deGrasse Tyson?

  That's for sure. Coming up, everything about the next generation gravitational wave detector on StarTalk. Welcome to StarTalk, your place in the universe where science and pop culture collide. StarTalk begins right now. This is StarTalk. Neil deGrasse Tyson, your personal astrophysicist, got with me my co-host Chuck Knight. Chuck, it baby, how you doing?

• 0:52Chuck Nice?

  Hey, what's up, Neil? How's it going, buddy?

• 0:55Neil deGrasse Tyson?

  Yeah, professional comedian and actor and.

• 0:57Chuck Nice?

  And acting like a comedian.

• 0:59Neil deGrasse Tyson?

  I've even seen you on TV on TV commercials.

• 1:01Chuck Nice?

  Yes, you have, but not enough, not enough TV commercials. That seems to be the problem. That's what I'm trying to convince the industry of is the public is clamoring for more Chuck Nice TV commercials.

• 1:13Neil deGrasse Tyson?

  Okay. So today we're we're revisiting a topic we've done in several different dimensions and several different angles.

• 1:26Chuck Nice?

  Really?

• 1:27Neil deGrasse Tyson?

  Yeah.

• 1:29Chuck Nice?

  See, this is this is when I wish I would have read the emails about what this show is going to be. Because I don't know.

• 1:42Neil deGrasse Tyson?

  We're going to be we're going to be talking about gravitational waves.

• 1:45Chuck Nice?

  Oh, sweet. Nice.

• 1:48Neil deGrasse Tyson?

  And while I know a little bit about it, I'm no expert. And so we combed the landscape and we found one of my colleagues who's on the frontier of that.

• 1:58Chuck Nice?

  Oh.

• 1:59Neil deGrasse Tyson?

  The future of gravitational.

• 2:03Neil deGrasse Tyson?

  Wave detection. Oh. That is in the incarnation of Kelly Holly Bockelman. Kelly, did I pronounce your whole rest of your three names correctly?

• 2:14Speaker 02

  Oh, yes.

• 2:15Neil deGrasse Tyson?

  That's a serial killer name if I ever heard one.

• 2:19Neil deGrasse Tyson?

  You're a professor of physics at Vanderbilt University. I think that's in Nashville, correct?

• 2:25Speaker 02

  It is, yes.

• 2:26Neil deGrasse Tyson?

  Nashville, Tennessee, recent chair of NASA's Laser Interferometer Space Antenna. Sensibly acronym. Lisa. Lisa, yes. Lisa. Of their study team and your recent chair of NASA's Astrophysics Advisory Committee.

• 2:44Speaker 02

  Yep.

• 2:44Neil deGrasse Tyson?

  Yes, I served on that many moons ago.

• 2:47Speaker 02

  Did you really?

• 2:47Neil deGrasse Tyson?

  Maybe before you were born, but I wasn't chair. I was just a member of that committee. This is the closest NASA has to a board, right? NASA has people who advise them, not only astrophysicists, but others in the full spectrum of NASA's portfolio. And you are director of the FISC Vanderbilt Bridge Program. Oh, my gosh. One of the most extraordinary and successful programs I have ever seen enacted. For its intent and its purpose. And in fact, I want to lead off with that. So Vanderbilt and FISC University have a partnership through this bridge program. Right? And if I understood it correctly, FISC does not have the full up research programming

• 3:32Neil deGrasse Tyson?

  and facilities that Vanderbilt does. And so in a bridge program, you get students from one university who can participate in another. Are you ahead of that? So tell me more about it.

• 3:43Speaker 02

  Yeah, thanks. It began about 20 years ago, so we're about 20 years.

• 3:47Neil deGrasse Tyson?

  Right, this has been going, yeah.

• 3:49Speaker 02

  It has been going. We started off with the idea that, you know, the traditional metrics that that choose graduate talent are, you know, things like standardized test scores and grades and.

• 4:04Neil deGrasse Tyson?

  That'd be the GRE, right?

• 4:05Speaker 02

  That's right, the GRE. They they select, you know, people who are really great at taking tests and and very smart people. But you know, science isn't like that. And so we need folks that have diversity of thought and background and who are creative to be able to tackle the big problems of today. And so, you know, we designed metrics that that search for that, that search for creativity and like, you know, community mindedness and, and yeah, that those are the things that that end up making scientists in our mind.

• 4:40Chuck Nice?

  Sounds to me like we're gonna have to cancel you.

• 4:43Speaker 02

  [laughing]

• 4:45Chuck Nice?

  Creativity, diversity of thought, diversity, all bad things.

• 4:53Neil deGrasse Tyson?

  So what's interesting to me, of course, is, yeah, you can, you can get high scores on an exam, but a modern science is no longer an isolated activity. You have collaborations, collaborators, you write grants, there's a public side of it, especially in our field. And these are dimensions of who you are that don't show up on an exam score, certainly not a standardized exam score. So this has been going for 20 years and you've been director the whole time.

• 5:22Speaker 02

  That's not true. I started, I've been director for, I think, maybe 10 years, but.

• 5:33Neil deGrasse Tyson?

  Still a long time. Still a long time. Well, I'm delighted to see that it's in, in your excellent capable hands and that it will continue to have a future as if it's not as good as certainly even better than what it is, the successes it has already achieved. So now, so that that's you as a, as a, as a citizen scientist in that regard. So now tell me about, about Kelly, the Lisa Maven. Our audience is not unfamiliar with efforts to detect gravitational waves. We've had LIGO on, yes, the entire array. The entire array. Every, every single laser got them right here.

• 6:16Neil deGrasse Tyson?

  So I want you to, can you share with, with me and Chuck and others, what is the primary difference between LIGO, Laser Interferometer Gravitational Observatory, and you? I guess you're in space, but other than that, why go to space?

• 6:32Speaker 02

  Got you. LISA, which is the Laser Interferometer Space Antenna, is, is in space because it's tuned to look for things that are in a different mass range. So like, if you think of LIGO, the, the kinds of, the things that it detects are massive black holes and, and that are, that are merging, and it takes just that, right? And that makes sense because the array, even though it's big, it's like four kilometers long for each of the arms. And so like the wavelength of the gravitational wave kind of fits in that size. And so if you want to detect things that are much more massive, you need really, really, really long arms. And

• 7:12Speaker 02

  arms that are so long that they're bigger than the entire Earth. You need to go into space.

• 7:18Neil deGrasse Tyson?

  Earth wasn't big enough for you?

• 7:20Speaker 02

  No, Earth, definitely. Yeah. So the, so LISA is an interferometer that is, that has arms that are like, that's sort of in a triangle shape. And the length between the two spacecraft, the arms are like 22.5 million kilometers, which is like-

• 7:39Neil deGrasse Tyson?

  So each side of the triangle is 2.5 million kilometers?

• 7:42Speaker 02

  It is so big that if you were to put it around the sun, which don't do that, because it's not a good idea, but if you were to do that, the sun would fit right, right in it. So it's like a star-sized telescope.

• 7:55Chuck Nice?

  It's the biggest dream catcher ever made. That's what you did.

• 8:02Neil deGrasse Tyson?

  A dream catcher. So obviously, these are not physically connected to each other. So how are they, how do you sort of station keep, as it were?

• 8:11Speaker 02

  Yeah, it's actually a misnomer that you even do that. You definitely don't want to station keep. You don't want to move these, uh, these masses around at all. What you want to do is let these test masses, that's what they're called. They're, they're, you know, roughly two kilogram gold and platinum cubes. They are mapping spacetime. So they are moving around in what is called geodesics or orbits that are going around the sun. And naturally they will map spacetime and you have three of them. And so they are three independent orbits in a triangle that kind of tumble. The way in which you detect gravitational waves is by looking for, uh, for deviations from, uh,

• 8:56Speaker 02

  from the lengths of the triangles. And that is because a gravitational wave has passed by, not because you've, you've oriented them or moved them in some way.

• 9:04Neil deGrasse Tyson?

  In a naive configuration, they would be rigidly connected and you'd be testing the effect on those rigid bars, right? But you can't have a three rigid bars encircling the sun. That doesn't make any sense at all. So am I, do I, am I correct to presume that it doesn't matter where they are as long as you know with precision how far away they are from each other at all times?

• 9:28Speaker 02

  Yep, that's the entire principle. Yeah.

• 9:31Chuck Nice?

  So maybe, um, can you help me? Because first of all, let me just if get my idea of station keep correct. That is when you keep, uh, something in orbit in a kind of a precise track so that it doesn't like solar winds or the gravity or something doesn't mess it up, right? So to Neil's point, this is what I don't understand. Wouldn't you have to keep them in some kind of precise synchronization in order to make sure that you're catching the wave so that there's no, I'll say like gaps in the fence? Or am I thinking about the whole thing wrong?

• 10:13Speaker 02

  Got you. I think what you're saying is you want to make sure that you're always communicating between the three different, uh, three different nodes of the, of the triangle. Is that what you're asking?

• 10:24Neil deGrasse Tyson?

  Right. Yes. Yes.

• 10:25Speaker 02

  Definitely want that to happen. So you're always sending a laser beam from one, um, part of the triangle, one's, um, little, uh, um, constellation piece, um, to the other. And that's what the, what the Lisa spacecraft is. It's this constellation of three, um, uh, three nodes and lasers shining between them.

• 10:44Neil deGrasse Tyson?

  And the lasers get, give you precise distances at all times.

• 10:47Speaker 02

  Exactly what they're doing. You're, what you're doing is your timing, how long it takes to go from one node to the other and back again.

• 10:55Neil deGrasse Tyson?

  But wait a minute, you have to know the speed of light to get that.

• 10:58Speaker 02

  You do.

• 11:00Chuck Nice?

  How do we know that?

• 11:02Neil deGrasse Tyson?

  Yeah, I think we have a, an explainer video on that where the speed of light is so well determined, it's actually defined. And then everything else is indexed to that.

• 11:11Chuck Nice?

  To that.

• 11:11Neil deGrasse Tyson?

  Yes. It's the most fundamental constant there is.

• 11:14Chuck Nice?

  That's why it's the big C, baby.

• 11:16Neil deGrasse Tyson?

  It's the little c actually in the equation, but.

• 11:18Chuck Nice?

  Yeah, true. That's true. You're right. Yeah.

• 11:22Neil deGrasse Tyson?

  The equals MC squared. That's a little c.

• 11:23Chuck Nice?

  That's a little c. You're correct. Yeah. The E is the biggie. The E is the biggie. The E is the biggie, baby.

• 11:45Speaker 03

  Hey, this is Kevin the sommelier and I support StarTalk on Patreon. You're listening to StarTalk with Neil deGrasse Tyson.

• 12:03Neil deGrasse Tyson?

  When does this launch? I mean, I remember reading about this decades ago. So what's taken you so long?

• 12:09Speaker 02

  I'm sorry. It's very complicated, Bill, but, um, we, uh, have the, the mission has been adopted officially. And what that means is that, you know, both ESA and NASA have decided this is a great, good idea. We're going to put our resources toward it and, um, it's supposed to launch in 2035, which sounds like a long way away, but it's not to build a whole spacecraft.

• 12:29Neil deGrasse Tyson?

  And so ESA, that's Europe, right?

• 12:33Speaker 02

  That's right. That's right. It's a European space agency.

• 12:35Neil deGrasse Tyson?

  Yeah, and so they've been collaborators on us with a lot of, a lot of space missions. And it's, it's always good to have international collaborators just for the, for, it's just new ideas from different people in different places and missions are always better when that happens.

• 12:52Chuck Nice?

  So can I ask this? I'm just curious. So LIGO already detected gravitational waves. Two black holes came together, washed over. We know that.

• 13:05Speaker 02

  Yep.

• 13:06Chuck Nice?

  What do you, what, what, what do you guys?

• 13:08Neil deGrasse Tyson?

  Chuck, were you paying attention three minutes ago when she said?

• 13:11Speaker 02

  So exciting. I'll say it again because I don't care.

• 13:16Neil deGrasse Tyson?

  Chuck was not paying attention.

• 13:17Chuck Nice?

  I probably wasn't, but go ahead.

• 13:19Neil deGrasse Tyson?

  Okay.

• 13:20Speaker 02

  Those black holes are the kind of black holes that are made from a regular stellar evolution. Like a star is born and then it dies and it has, those are things are called stellar mass black holes. And they're about eh, 10 to maybe 100 times the mass of our sun. And those are cool. I, you know, whatever, but they're not my favorite. The, my favorite are the kind that are, you know, millions of times more massive.

• 13:44Chuck Nice?

  So they're super massive?

• 13:46Speaker 02

  Yeah, that's right. Well, massive, not super massive, but anyway.

• 13:49Chuck Nice?

  Okay, so wait, now back it up. Wait, what's the difference between super massive and massive? Because now the-

• 13:55Neil deGrasse Tyson?

  Super massive is bigger, Chuck. Stay with the program here, Chuck.

• 14:00Speaker 02

  There's so much dorky ways of saying things.

• 14:03Chuck Nice?

  I love it.

• 14:04Neil deGrasse Tyson?

  Kelly, if I remember correctly, you're, you professionally studied colliding galaxies? Because they, they would have a supermassive black hole in each of them.

• 14:15Chuck Nice?

  Each of them.

• 14:15Neil deGrasse Tyson?

  Or a massive black hole, and they might get together if the two galaxies collide. So is this what birthed your interest in this category of black holes?

• 14:24Speaker 02

  Yes. And so we know galaxies have-

• 14:29Speaker 02

  A massive black hole at the center, that's maybe, you know, millions to billions of times the mass of our sun. And we know galaxies grow by merging together. And if each galaxy has a black hole in the center, then when the galaxies merge, presumably the two massive black holes merged.

• 14:43Neil deGrasse Tyson?

  Is it a guarantee that they'll find each other?

• 14:45Speaker 02

  Not 100% guarantee, but that's the research I do. I use supercomputer simulations to figure out how long that process takes and what kinds of changes that makes to the galaxy that it lives in. So I study the time scales over which that happens.

• 15:01Neil deGrasse Tyson?

  Interesting. So what rate detection do you expect? Because, you know, the universe is full of images of pretty ratty-looking galaxies that have been all torn up from a collision. But that doesn't mean in that instant, the two black holes merged, right? So how often, if, if, if, yes, this happens, but it happens once every thousand years, you're SOL on this, right?

• 15:29Speaker 02

  Well, yes and no. I would personally be SOL on that science topic, but, so I'll come back to the answer to your question here. But I want to make sure that y'all know that Lisa would still be great, even it would not detect any of the massive black holes. And that is because as soon as Lisa turns on, you're going to be able to detect all of the individual stellar mass black hole binaries and neutrons die binaries and white dwarf binaries. There's supposedly 10 million of these in our Milky Way.

• 16:01Neil deGrasse Tyson?

  So this would be like a din of gravitational wave noise coming washing over Lisa?

• 16:08Speaker 02

  Yes.

• 16:09Neil deGrasse Tyson?

  Oh, my gosh. Wait, wait. So, so you can detect those wavelengths because they haven't collided yet, right?

• 16:16Speaker 02

  Exactly.

• 16:17Neil deGrasse Tyson?

  The wavelength is on the scale of the size of their orbits.

• 16:20Speaker 02

  Exactly.

• 16:21Neil deGrasse Tyson?

  Oh.

• 16:22Speaker 02

  Exactly. So by by making something as big as Lisa, you're catching all of the sources that are loud and orbiting around one another on time scales of of an hour. And there's a lot of astrophysics that does that. Like, yes, there's these massive black holes that I love when they're colliding, but also these individual stellar compact object binaries is what they're called. There's even these things that are called Emre's, extreme mass ratio inspirals. And that is one massive black hole, but then little black holes orbiting around.

• 16:54Neil deGrasse Tyson?

  And then falling into it.

• 16:56Speaker 02

  A million years to do that. And so they're like, orbiting around this. Sorry, everybody, but they're orbiting around this massive black.

• 17:03Neil deGrasse Tyson?

  We like the sound effects. Those are good. The race track sound effects. Never get old.

• 17:10Speaker 02

  Excited about it. Sorry. But neat thing is that it traces spacetime like all over the place. The orbits are beautiful. I wish that you could see them. And I wish that we will see them. We'll be so.

• 17:21Neil deGrasse Tyson?

  When we had Nurgus Mavolala on from LIGO, she didn't tell us that they were detecting sort of the smallest waves, but that's what they're doing. They're starting at the bottom of this ladder of wavelengths of possible gravitational wave detections. Is that that's correct?

• 17:40Speaker 02

  You are precisely right. The wonderful thing about Lisa is that it's opening this new window to the universe. And every single time we open a new window in the universe, we discover something we've never expected. And so I can tell you all day about what we think we'll we'll detect. And for sure, we think we're going to detect some stuff. But the most exciting thing is that there's going to be something that we don't know that is in that window. I can't wait.

• 18:03Neil deGrasse Tyson?

  Wow. Excellent. Let me get back to the detector briefly. Why three nodes? Why not four, or two, or six? Yeah. Where does three come in? And tell me about these objects. Why are they two kilograms? Why not 10 kilograms? Why? Why not a BB sized? But who's thinking this up? And why why is it those? That configuration in that shape.

• 18:29Chuck Nice?

  And are these little kilograms nodules, are they kind of like the bell ringing? Is that the whole deal?

• 18:36Speaker 02

  They are ki- I like it, well, they're tests, they're called test masses. And I like to think of them as they are the things that are, that are probing the space time, meaning that they, their orbits and where exactly they are in space and time, they're the things that the lasers are measuring the distance between.

• 18:54Neil deGrasse Tyson?

  They're the rubber ducky on the wave.

• 18:56Chuck Nice?

  On the wave, on the wave itself.

• 18:59Speaker 02

  This is why y'all get paid the big bucks.

• 19:01Neil deGrasse Tyson?

  No.

• 19:02Speaker 02

  They're the rubber duckies. They're super sensitive and gorgeous rubber duckie.

• 19:06Neil deGrasse Tyson?

  They're bobbing up and down on the gravitational waves as they wash across. You mentioned that they were cubes, but why? Why, if it's, if it's just a test mass, a test, a test particle in the space time continuum, what is a cube getting you that a sphere wouldn't be? And a sphere is just kind of cool anyway.

• 19:28Speaker 02

  I, I'm with you. When I was new to this, I thought I was going to be brilliant and tell everybody why not a, why not a sphere? And someone took me aside and said, you can't machine spheres to the precision that you need a cube. And so I, I trust them. This has been something that folks have been thinking about for, for, you know, a generation, for 50 years now.

• 19:53Neil deGrasse Tyson?

  So I learned that in seventh grade.

• 19:56Speaker 02

  Did you?

• 19:57Neil deGrasse Tyson?

  Yes, I did. In my seventh grade wood shop, this is, that's how old I am, back when they segregated boys from girls. Boys went into shop and the girls went into home ec. Okay? And so in my wood shop, I laved a sphere to become the ball of a Saturn lamp that I manufactured.

• 20:16Chuck Nice?

  Which he still has, by the way.

• 20:17Neil deGrasse Tyson?

  I still use it ever since I was in seventh grade. It's still on my desk. I'm not at my office in this moment. And, but that sphere, as you, you, you start with a cube and you lave it down, but then there's still the two parts that are attached that are spinning. And then how do you get to those? We have to plug it on to the other side and you just can't get the sphere. You, you can't, there's no way to, to hold it and carve it. And so I'm all with you. I experienced that firsthand.

• 20:47Chuck Nice?

  I did not because I went to home ec and I sued to do so because I didn't want to lose any fingers.

• 20:55Speaker 02

  I don't know, those hand mixers can be pretty...

• 20:59Neil deGrasse Tyson?

  And tell me about why three and not four or five?

• 21:02Speaker 02

  There are other designs. In fact, there are plans for a Chinese gravitational wave mission that does use four arms.

• 21:12Chuck Nice?

  Of course. Of course. We put up three, and of course, China, China has to put up four.

• 21:21Neil deGrasse Tyson?

  But if they're just test bobs, but they're test bobs equipped with lasers, so something could go wrong.

• 21:26Speaker 02

  That's right. And so if you have three and you lose one, you still have two, so you would still have a gravitational wave mission. I think this is just one of those instances where you have a cost benefit analysis and, you know, it would be more expensive with four or five. So, so three is kind of the ideal configuration.

• 21:46Neil deGrasse Tyson?

  Okay, I don't mean to post judge out of my own ignorance what's going on here, but if you're just putting up cubes, this sounds like a really cheap space mission. You know, what do you, what do you tell to the Mars rover people, right?

• 22:04Neil deGrasse Tyson?

  With a thousand pieces of scientific equipment attached to it is the size of an SUV. We're putting up a two kilogram cube.

• 22:10Speaker 02

  No. It's not just that, right?

• 22:15Neil deGrasse Tyson?

  Come out of your mouth about it.

• 22:19Speaker 02

  There's more to it than that.

• 22:20Neil deGrasse Tyson?

  Okay, I'm glad to hear that. Okay. No, so it's got to have, it's, it's embedded in something where it can perform the measurements, presumably.

• 22:28Speaker 02

  That is correct. And so there's very sophisticated interferometry. You have to have, and, and you do have to have some things as, as much as, like, for example, if there were a solar windstorm, you get these, you get charges that are on the, the test mass, and that can cause it to drift electrostatically a little bit. Well, that's not a gravitational wave. You need to have some way to discharge that. And so there's special LED discharging mechanisms that have been invented by, by folks in the US to be able to...

• 23:00Neil deGrasse Tyson?

  For this purpose.

• 23:01Speaker 02

  For exactly this purpose.

• 23:03Chuck Nice?

  Wow.

• 23:03Neil deGrasse Tyson?

  Yeah.

• 23:04Chuck Nice?

  Look at that. USA, USA, USA.

• 23:10Neil deGrasse Tyson?

  Scientists would never do that, so I gotta do it. I gotta do it for you.

• 23:18Neil deGrasse Tyson?

  So I'm trying to think of other things you'd have to correct for. If it's a big old triangle, of course, the path length starts out at its farthest point from the sun. Then it gets its closest point to the sun in mid-leg of the triangle. And then it moves out to the other edge of the triangle. But when it's closer to the sun, it's at a different gravitational potential than it was at the nodes. Wow. And since this, so this works just for regular gravity, of course, but also relativity is going to matter here. Just so you know what that effect is, so that you don't then credit colliding black holes with it. Wow.

• 23:59Speaker 02

  Absolutely. I mean, it ends up being, you know, not only that, but, but individual parts in the, in this constellation. You have to weigh each object that you put in, each little cable, very, very, very distinctly, because that causes a gravity gradient and that's gonna, you know, mimic a gravitational wave.

• 24:17Neil deGrasse Tyson?

  That is so detailed. So the thing could end up detecting itself, is what you're saying.

• 24:23Speaker 02

  Yeah, yeah. Unless you screw. There's another thing that, that's called tilt-to-link coupling, where like, just like you said, you have, when you have a cube, and there's a little bit of radiation pressure, which is gonna cause, put a little force, it's gonna torque it. And so you'll get this cube rotating back and forth. And that difference is gonna be, it's gonna mimic a difference in the path length, because you're gonna hit it not perpendicularly. And so this, you know, bobbing back and forth is, is something that you have to correct for.

• 24:51Neil deGrasse Tyson?

  Yeah, yeah. And so, as I understand it, at least I'd learned this from, from LIGO, because the LIGO has multiple. Observatories, right? There's Louisiana, there's one up in the Pacific Northwest. I think there's one in India. There's a bunch around the world. So part of your confidence that you've detected something real is that there is the wave washes over one detector, but not the others yet because it's moving at the speed of light. And you have this huge distance and it gets to the others and you time that out. You say, oh, it's coming from that direction and it worked out. And it's not just a hoax or a prank put on by one detector on the other two detectors.

• 25:31Chuck Nice?

  Speaking of detection, um, so I don't know exactly how to describe the LIGO detection, but I know it's so, so, so, so, so, so tiny, tiny, tiny, tiny. So since you're detecting all these different, like, okay, like you said, the pulsars and then the supermassive.

• 25:52Neil deGrasse Tyson?

  Bigger wavelengths.

• 25:53Chuck Nice?

  Bigger wavelengths, thank you. Are you going to get bigger measurements? Or what are the difference there that makes you say, hey, we got it?

• 26:04Neil deGrasse Tyson?

  I'll say what Chuck said, but I'll do it in two sentences.

• 26:07Chuck Nice?

  Thank you. Thank you, sir. I'm okay with that.

• 26:12Neil deGrasse Tyson?

  They were so precise, they could measure the fraction of a diameter of a proton.

• 26:16Chuck Nice?

  Right.

• 26:16Neil deGrasse Tyson?

  So how, what kind of precision do you need to detect the black hole or the gravitational signatures you seek? Is that what you're trying to say, Chuck?

• 26:24Chuck Nice?

  That's exactly what I was trying to say. And, you know, that's what I, that's why I have you.

• 26:33Speaker 02

  Y'all make a good team.

• 26:34Neil deGrasse Tyson?

  Okay.

• 26:35Speaker 02

  So, uh, yes, um, we do have to have things that are that relatively precise. So we aren't detecting things a fraction of a proton, um, uh, length, not, not detecting relative changes on that scale. But that's only because our, our constellation is so big. So we're just detecting, um, changes one part in 10 to the minus 20, because that's how strong the gravitational waves are. But, um, but because the, the, um, the mirrors are, are separated so, uh, um, by such a huge distance. Then, you know, the differential scale is ends up being bigger.

• 27:15Speaker 02

  But the other thing is that many of these massive black holes, when they merge, they're so loud. And so the kinds of signals that we're going to get are having signal to noise ratios of thousands. So.

• 27:30Neil deGrasse Tyson?

  That's not even fair.

• 27:31Chuck Nice?

  You're catching a fly ball with one of those novelty gloves.

• 27:40Neil deGrasse Tyson?

  Big oversized gloves.

• 27:42Chuck Nice?

  The big giant oversized gloves. You're out in center field, Mike.

• 27:47Neil deGrasse Tyson?

  I like the baseball analogy there. Tell me he's not wrong. Tell me.

• 27:53Speaker 02

  He's not wrong in that these are really, really loud signals. And so your instrument just has to work and then you'll definitely catch the, you know, the gravitational wave signal. But you have to get up there and it takes a while to build the instrument to get up there.

• 28:10Neil deGrasse Tyson?

  So the fact that we're collaborating with ESA, the European Space Agency, or do I say that in reverse? ESA is collaborating with us. Does that give the funding stream a little more sort of reliability into the future? Because if we default, then would you stop, Chuck?

• 28:32Neil deGrasse Tyson?

  Chuck, stop.

• 28:33Speaker 02

  You're hurt right now, y'all.

• 28:36Neil deGrasse Tyson?

  Chuck, stop.

• 28:39Chuck Nice?

  Oh, my God. Hey, welcome to America, people.

• 28:43Neil deGrasse Tyson?

  Ask a question.

• 28:45Speaker 02

  And I'm trying not to cry right now, y'all.

• 28:47Chuck Nice?

  Oh, God.

• 28:48Neil deGrasse Tyson?

  I'm sorry. I'm just trying to think of the missions that have had the most stability, funding stability. Because, you know, 2035 is still 10 years away. And, yeah, when Kennedy said, we'll put a man on the moon, return him safely to Earth, before the decade is out, that was an eight-year horizon, and we did it in seven years. But of course, we were at war, you know, we had the godless commies. You know, we had all the mechanisms in place to persist in that goal. You need more of these interviews to help out? You got to get more TED Talks? I saw your TED Talk a few years back.

• 29:30Chuck Nice?

  Before they actually come up with a, instead of Doge, Dun, Department of NASA efficiency.

• 29:38Speaker 02

  Yeah, I'm gonna, I'm gonna turn serious now because that's actually happening. You know, they, the, the, the latest president's budget request has zeroed out, Lisa. And so we are a partnership with ESA and, and NASA. NASA is a junior partner. And the US, if, if this request goes through, the US can no longer participate and, and give our technology to, to this mission.

• 30:08Neil deGrasse Tyson?

  Okay, so here's how you do that. Based on my, I feel like an old ti- old time wise man on the porch now.

• 30:16Chuck Nice?

  Nah, I remember we were just trying to push something up on the moon. See? Now lots of people were coming around and saying, now, first of all, how you gonna land something made of cheese? And we told them.

• 30:31Neil deGrasse Tyson?

  So here's what, here's what has to happen. If we pull out, then China rises up, we'll take their place.

• 30:40Chuck Nice?

  Oh, God.

• 30:41Neil deGrasse Tyson?

  Oh, my gosh. So then we lose our shit and say, no. And I, that's, that's how, that's.

• 30:50Chuck Nice?

  That's how it goes.

• 30:51Neil deGrasse Tyson?

  Yeah.

• 30:51Chuck Nice?

  I said, you know what? That's a very good point, though, because that's the one thing that.

• 30:55Neil deGrasse Tyson?

  That'll put a flame under people's butts.

• 30:56Chuck Nice?

  That'll put a flame under our butts is if China tries to do something that we should be doing, you know? Yeah. And so hopefully that'll be.

• 31:06Speaker 02

  You're totally right. I'm sorry I interrupted you, but like, as a scientist, I'm, I'm glad there's, there's two other Chinese gravitational wave observatories that mimic Lisa, because that means there's more probability that, that this science that I love will actually happen. But we are losing out. We're not going to be able to have the, you know, technological know-how. We're not going to have the stable of people who can solve big problems. And so we lose out and that sucks for us. Yeah.

• 31:40Neil deGrasse Tyson?

  So we've seen something like this happen before, but the motivations were all different. When we were building the superconducting supercollider in Texas and is the world's largest, most powerful collider. And that was in the late eighties. And then early nineties, what happens? Peace breaks out in Europe. Can't have that. That'll totally disrupt funding for for science that you perceive would be in the interest of national defense because they were all physicists doing this and physicists won the Second World War. So that budget gets zeroed. But as a scientist, I'm echoing exactly what you said, but from the point of view of particle physics, somebody in the world is going to do it. Just because we don't do it doesn't mean it's not going to happen. The

• 32:21Neil deGrasse Tyson?

  center of mass shifts and it shifts and all the glory goes to other countries and the Nobel Prize is all around. And so, yeah, it's it just becomes a shift. But it'd be a shame if you were not front and center of that because you've put your life to this.

• 32:37Speaker 02

  I get it. I also think it's just, and I think I'm echoing some of those things that y'all y'all are saying too. It's just that the act of building this humanity scale scientific endeavor, the act that we're participating in that trains us, trains our, you know, it allows us to have a pool of people who are prepared to tackle the next challenge. I was just talking with a friend the other day who said, you know, there's always these disaster movies and then somebody, you know, comes and says, let's get us the scientists to solve all the problems. And it's usually somebody from NASA that comes to like save all save save the earth. But we won't have those people if we are not participating in these, you know, big challenges. So.

• 33:22Neil deGrasse Tyson?

  But what you missed something and you missed something in the disaster movies because that yes, the scientist solves it in the end, but the disaster movies always begin by government officials ignoring the warnings from scientists.

• 33:35Chuck Nice?

  That's true.

• 33:39Neil deGrasse Tyson?

  That's how that begins. There you go. You know, like in the documentary, Don't Look Up, you know, but Netflix documentary.

• 34:14Neil deGrasse Tyson?

  So Kelly, what other missions or what other science might be inspired by this work, either scientifically or technologically?

• 34:21Speaker 02

  Yeah, I think that's great. I personally am excited about the gravitational wave aspects, but there's a lot of technology that can be used for the efforts for things like the Moon to Mars effort. So needing to know exactly where we are is GPS. And so, you know, LISA is really going to be developing that technology. The communication, laser communication, is going to be something that we'll need to have, you know, prepared. And so all of these technological pieces, which have nothing to do with gravitational waves, are being developed and will be really useful for things that are our nation's priorities.

• 35:01Neil deGrasse Tyson?

  Wait a minute. Did you just imply that you are on the cusp of technology that will give travel through the solar system the coordinate equivalent of what GPS does on Earth's surface? So it'll be a solar system positioning system, not a global positioning system?

• 35:25Chuck Nice?

  At Saturn, make a left.

• 35:30Neil deGrasse Tyson?

  Recalculating.

• 35:34Speaker 02

  No, really, GPS is not going to be sufficient for where we need to go in the future, and LISA really helps us get there.

• 35:41Neil deGrasse Tyson?

  So is there a term for it? I mean, like SPS, solar system positioning system? We need a good acronym there.

• 35:48Speaker 02

  I'm sure there's probably an acronym, but if not, I will ask my friends.

• 35:52Neil deGrasse Tyson?

  I'd heard that there was some thoughts of using pulsars in the galaxy as a global positioning.

• 36:01Neil deGrasse Tyson?

  As a galactic positioning system, have you, are you on top of that? Have you heard of that? Yeah, that is dope. Yes, I know, because pulsar is very precise. Very precise. And if you know where they are. Oh, that is brilliant. If you move a little to the left, the signal from that pulsar is a little delayed compared with that one. And you triangulate, you know exactly where we're at in the whole galaxy. Damn.

• 36:26Speaker 02

  So that actually I have a friend right across from the hall from me at work. Um, who is part of the effort to do, um, to nanograph, which is this, um, pulsar timing array. Uh, and one of the things he specialized in was recognizing that the pulsars, um, when you timed them, they gave you, there, you needed to know where you were in the solar system. So this, what is called the solar system berry center. You needed to know your position in the solar system really, really well. And so far we calculated it wrong. And so that had added a big error to whatever they were calculating. And so you, that, that pulsar stuff helped us understand our place in the solar system.

• 37:09Neil deGrasse Tyson?

  Our own place. Our own place, right.

• 37:11Speaker 02

  In the solar system, yes.

• 37:12Neil deGrasse Tyson?

  Yeah, just not just for the, for everyone listening, there are two categories of errors. And Chuck, maybe we'll do an explainer on this. There, there are statistical errors, which will fluctuate around the actual answer you're trying to get. And then there's systematic errors.

• 37:28Speaker 02

  Yep.

• 37:28Neil deGrasse Tyson?

  And these are errors that, oh my gosh, it's not even where, the answer is not even where I've been looking because the wall current changed or because I had a wrong assumption. And that's a whole, uh, the, the entire, uh, direction the experiment is going is wrong because of a systematic error. So two whole different kinds of errors. So this sounded like, of course, a systematic error. Absolutely. Yeah, one is stop and ask for directions. The other is, we're not in Kansas anymore, too.

• 38:00Neil deGrasse Tyson?

  So what is the balance of funding that's making Lisa go?

• 38:03Speaker 02

  Well, right now, we are the junior partner to ESA. And for those of you who are concerned that Lisa would not go without without us, ESA is fully prepared to be able to go on it, go on with the mission without the US participation.

• 38:19Chuck Nice?

  There's a lot of that going on in the world right now, Kelly.

• 38:24Neil deGrasse Tyson?

  It's fading. You fade to irrelevance on the world stage.

• 38:28Speaker 02

  Before gravitational waves are detected, there was another funding snafu and and NASA pulled out of Lisa again. And so ESA was left stranded. And so by now, we had broken up with them once. And and ESA said, you know, we're going to have a contingency plan. And so now we could well be breaking up with them again. And there has been talk about whether or not they would let us back, which I, you know, personally, I don't know if I blame them. We broke up with them.

• 38:57Neil deGrasse Tyson?

  Breaking up is hard to do.

• 38:58Chuck Nice?

  Yeah, yeah.

• 39:00Speaker 02

  I hope they don't.

• 39:01Neil deGrasse Tyson?

  As long as you, you know, warmly once, Blake's, you, whatever, however that goes.

• 39:06Chuck Nice?

  Look at that. It turned into a space disco. Like, once you leave, you can't get back in. I'm sorry.

• 39:15Neil deGrasse Tyson?

  Could you spend a couple of minutes giving maybe a one sentence explanation of interferometry?

• 39:25Chuck Nice?

  One sentence?

• 39:29Neil deGrasse Tyson?

  I'm just, you know, testing my people here, Chuck.

• 39:32Chuck Nice?

  And while you're while you're at it, Kelly, can I can you can you also distill the meaning of life into one sentence? Could you do that too, please?

• 39:41Neil deGrasse Tyson?

  That word, because it's in the acronyms, it's it's it's spilled into the public. But it's I don't I've never seen a really good explanation. So I want you to give us a stab at it.

• 39:52Speaker 02

  I will do my best. I always think of it like a light race. And so in an interferometer, you will often, like LIGO, for example, you will shine a laser from one part of an instrument to another and have it bounce back. And if, and same for the other direction, you will shine a laser in another direction, have it bounce back, and if the time it takes to go from one side of the arm to another is exactly the same, then the light will interfere with each other. And that's where the interferometer part comes in. When the light interferes with each other, they cancel each other out, and you see no signal. But if the arm lengths are a little bit different,

• 40:34Speaker 02

  then it takes a little bit more or less time to go along one arm. And so by the time the light gets back, the light doesn't perfectly interfere anymore, and you get to see a little bit of light still left over. And so that's kind of how an interferometer works. It's a light race.

• 40:51Neil deGrasse Tyson?

  So Kelly, so the secret fact here is that a laser is not only an intense beam of light, it's actually perfectly in phase with itself, right? So you can just think of waves coming out, carried by a laser phenomenon. And so I think if people think of just these crests and troughs going out and coming back, they either line up with each other or they don't, right? And the amount they don't line up tells you how much the two path lengths are different.

• 41:21Speaker 02

  Exactly.

• 41:22Neil deGrasse Tyson?

  And in fact, Chuck, I don't know if we talked about this, the invention of the interferometer itself got a Nobel Prize. Just that apparatus was proved so useful.

• 41:34Chuck Nice?

  Wow.

• 41:34Neil deGrasse Tyson?

  And it was the two guys who discovered that, who first measured the speed of light. And global core lasers even, but.

• 41:41Chuck Nice?

  Yeah, yeah. I thought that was the two guys on the, on the mountaintops with candles.

• 41:48Neil deGrasse Tyson?

  No, that was in Galileo's day.

• 41:50Chuck Nice?

  Okay.

• 41:51Neil deGrasse Tyson?

  Well, how'd you know about that?

• 41:52Chuck Nice?

  I think I listen to you sometimes.

• 41:57Neil deGrasse Tyson?

  So Galileo, brilliant guy, he sends his friend over to another mountaintop with a lantern, with a little shutter, and he says, when I open my shutter, you open your shutter, and I will time this. And so they did this, and on a far mountain that he could see. And then he wrote, I love this, he said, if it's not infinitely fast, it is faster than I could measure. But he said it in a cooler way than that, in a, you know, sort of old, old fashioned, the Italian sentence. But yeah, yeah, he tried that. So that's, think about that, Kelly.

• 42:35Speaker 02

  Yeah.

• 42:35Neil deGrasse Tyson?

  There's Galileo just trying to send candlelight from one mountain to top to another, and you were beaming lasers across the solar system. Wow. And that's been 400 years, 400 years. Wow.

• 42:48Speaker 02

  I think it's, it's like how we, we share knowledge and build on one another, and how the, the nature of, like you said, of collaborating and really working towards something bigger than, than we knew before.

• 43:01Neil deGrasse Tyson?

  So Kelly, if ESA is the principal funder, are they building the spacecraft themselves?

• 43:08Speaker 02

  Uh, no. Bits and pieces of it are being built by, by different nations, and we all put it together. So for example, the US is responsible for the laser, uh, the, this charge management system that I talked about, and the telescope.

• 43:24Neil deGrasse Tyson?

  So if you shiny lasers, you need something to detect them. And so, so you got some kind of a telescope device on each one?

• 43:31Speaker 02

  Yes. Um, each one, there are telescopes that, that are actually made out of glass. It's a very, very, uh, temperature-stable glass called Xerodur, and it's translucent. Um, and so if you kind of, which I think is really cool, there's a picture of it where you can, where there's like a test model of it right now, and they shine a light underneath it, so it glows really, really well.

• 43:53Neil deGrasse Tyson?

  So when he said stable, what, are you saying, I think this is what you're saying, that as the temperature fluctuates in space?

• 44:01Speaker 02

  Yes.

• 44:01Neil deGrasse Tyson?

  The material does not expand or contract?

• 44:06Neil deGrasse Tyson?

  And so in that way, it doesn't affect the optics or any other measurements you're trying to make.

• 44:11Speaker 02

  You're exactly right. The whole name of the game for Lisa is to keep everything as still as possible. Extra charges, even even air that would be left over in the instrument. Sometimes there's this outgassing that you do to get rid of all the air in a space instrument. But individual air molecules hitting that test mass will fake a gravitational, it'll make it move. It'll make that test mass move and make it seem like a gravitational wave.

• 44:38Neil deGrasse Tyson?

  But you're in space, so where are you getting air molecules?

• 44:41Speaker 02

  Well, it's left over from the.

• 44:43Neil deGrasse Tyson?

  Left over.

• 44:44Speaker 02

  Yeah, that's what happened.

• 44:46Neil deGrasse Tyson?

  I remember I was in Bell Labs when I was in high school and I was in a part where they, we were experimenting with high temperature superconductors. That's not what matters here. They put they put these devices in a vessel and create a vacuum around it. And I say, that's a pretty good vacuum. And so we're not done here. They heat it up.

• 45:08Speaker 02

  Yeah.

• 45:08Neil deGrasse Tyson?

  And then all the air molecules that were in the surface of the material come out. And the pressure goes back up and you gotta pump it again. It's like, whoa. We're not thinking that this stowaway air molecules in the texture of the surface of the material.

• 45:25Speaker 02

  Absolutely. That's that outgassing stuff that we were just talking about. In fact, sorry, story time.

• 45:32Speaker 02

  As I said, you need to keep the instrument as stable as possible. And there was a big, like, how are you actually going to make Lisa? You need to have, you know, what about solar wind? Could that push the test mass, etcetera? So there was this Pathfinder mission called Lisa Pathfinder. And its only job, its only job was to say, how still can we hold that test mass into space? And it performed exquisitely, like a thousand times better than it was expected to perform. And when you look at, you know, the tiny fluctuations in the test mass way afterwards, the tiny fluctuations were caused by individual air molecules hitting.

• 46:15Speaker 02

  That test mass because they didn't out gas they thought ah we don't really we need to be this accurate so we won't out gas as well as we thought but heck yeah individual air molecules

• 46:26Neil deGrasse Tyson?

  So why didn't solar wind just blow the thing out of the out of orbit?

• 46:29Speaker 02

  The the constellation is a big enclosure for that test mass and so it will react and move in such a way to like counteract the the air mode the the solar wind

• 46:43Chuck Nice?

  Radiation yeah.

• 46:45Speaker 02

  But keep that test mass still so it

• 46:48Neil deGrasse Tyson?

  Wow.

• 46:48Speaker 02

  Yeah.

• 46:49Neil deGrasse Tyson?

  Okay and what about the fact that the side of the spacecraft that's facing the sun gets much more radiative energy heat than the side that's facing away doesn't that itself put a pressure on the object and try to push it into a different orbit?

• 47:06Speaker 02

  Absolutely there's radiation pressure as well and and so you know you build the instrument with you know with the ability to compensate for that fact of known air of no radiation pressure.

• 47:18Neil deGrasse Tyson?

  Every now and then we see a news article about primordial black holes or or black holes around the big bang can this detect anything any sort of gravitational waves like a gravitational background where we have a cosmic microwave background there's something from the big bang that's waiting for you to turn on

• 47:39Speaker 02

  Whoa. If dark matter were primordial black holes and if some of them were to merge or even be close enough so that they're orbiting on you know a half hour hour time scales they will be observable with Lisa so I've been working on predictions for for what the Lisa's signature would be of these these primordial black holes and yeah definitely if they're there Lisa would detect them.

• 48:04Neil deGrasse Tyson?

  And secretly do you want your predictions to come true or do you want them to not match what's measured? Revealing to you that there's some physics going on you had not foreseen.

• 48:18Speaker 02

  Definitely the second. I cannot be wrong. That's the coolest part.

• 48:23Neil deGrasse Tyson?

  Say that out loud.

• 48:25Speaker 02

  I cannot wait to be wrong.

• 48:26Neil deGrasse Tyson?

  Thank you.

• 48:28Speaker 02

  That is the best part is like, there's gonna be something like, like, for example, when, right before the discovery of, not discovery, the detection of gravitational waves with LIGO, you ask any astrophysicist, what is the mass of a stellar mass black hole? They say 10 solar masses. I have, I, in grad school, had tests and I wrote 10 solar masses and if I didn't, I would be wrong, because they would mark you off. What did, what did LIGO detect? 30 solar mass black holes. And so immediately afterwards, all the astrophysicists were like, how do we make these black holes? I don't know. They went back to their drawing board and we learned a whole bunch of really cool stuff. That's gonna happen when LISA launches and it's gonna be the best thing. It's gonna make us all wrong.

• 49:12Neil deGrasse Tyson?

  And the press never gets this right, because they, they want the public to think that we're all just sitting in our office with our feet up on the desk, basking.

• 49:21Chuck Nice?

  We got this.

• 49:22Neil deGrasse Tyson?

  We got this. And they think that somehow, something shows up that, that ruffles the feathers that somehow we will be shocked or be, but will upset the apple cart of our cherished theories. They have no idea how delighted we are when stuff breaks.

• 49:39Speaker 02

  Absolutely. And that, that kind of goes back to the, to the FISH program. We are, we search for folks who will be comfortable and excited about not always getting the right answer. I think that makes the best scientists.

• 49:55Neil deGrasse Tyson?

  Yes.

• 49:56Chuck Nice?

  Right. You guys should have looked for me.

• 50:00Chuck Nice?

  That's where I'm a Viking.

• 50:02Neil deGrasse Tyson?

  Well, Kelly, it's been a delight having you on. And we wish you luck because we know you need that on top of what it is to be smart, to get these missions through, because there's so many. What do you call them puppet strings operating on budgets? And so good luck with this and we have to get you back when it's on the launch pad.

• 50:26Chuck Nice?

  And if I might, if I might just say to all the listeners, it would not hurt for you to contact your representative and say just like this, goddamn boy, I'll tell you one thing, if we don't get that doggone Lisa up there in that sky, I don't know what the hell we're gonna do. It'd be a cold day and a blackness of space before I wanna see some Chinese taking over what we supposed to be doing. Now that's what I'm trying to figure out. Now, if you wanna stay in office and you know what's good for you, you might wanna release a few of them duckets over there to that Lisa program. That's all I'm saying.

• 51:03Neil deGrasse Tyson?

  So that's how you convince your members of Congress.

• 51:05Chuck Nice?

  Something like that, something along those lines.

• 51:09Speaker 02

  We have a website called savelisa.org and it tells you exactly how you contact your rep.

• 51:14Neil deGrasse Tyson?

  Thanks Kelly for being on StarTalk.

• 51:16Speaker 02

  Thank you.

• 51:17Neil deGrasse Tyson?

  Chuck, I think there's a cosmic perspective due here. What do you think? There better be. Once again, on the moving frontier of science, especially on the frontier of space, we are on the brink of opening up a new window to the universe. And just as you open any window and look out of it, there's gonna be a view you haven't had before. There's gonna be things to see, to learn, to test, to explore, to take your curiosity into places previously expected perhaps, but at its best, places you have yet to dream of. And there is the finest way we can advance science.

• 52:01Neil deGrasse Tyson?

  And by the way, it's, it's, yes, you can do it from an armchair with a pen and pad, but persistently in the history of astrophysics, major advances have come when we join forces with engineers and say, look, we wanna detect this, we wanna accomplish that. The astrophysicist is not the engineer. The engineer is the engineer. You bring that together and then you get this new generation detector, equipment, telescope, measuring device that opens up.

• 52:35Neil deGrasse Tyson?

  Whole new places in the universe for us to explore. And the urge is to think, oh, then we'll know what's going on. But that's not what the history of this exercise has been. Instead, what we do know and what happens every single time is that as we grow our area of knowledge, so too grows the perimeter of our ignorance. So that science indeed is an endless frontier. That is a cosmic perspective. Kelly, great to have you. Thank you. Chuck, always good to have you there, man.

• 53:18Chuck Nice?

  Always a pleasure.

• 53:19Neil deGrasse Tyson?

  We'll look for you in the commercials that you're not in. Until next time, Neil deGrasse Tyson, bidding you to keep looking up.