StarTalk Live! LIGO and the Black Hole Blues (Part 1)

Everything you ever wanted to know about gravitational waves, explained by Neil Tyson, Eugene Mirman, cosmologist Dr. Janna Levin, LIGO astrophysicist Dr. Nergis Mavalvala, and comedian Michael Showalter. Recorded live at the Count Basie Theatre in Red Bank, NJ.

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

• 0:02Neil deGrasse Tyson?

  Welcome to StarTalk. Your place in the universe where science and pop culture collide. StarTalk begins right now.

• 0:23Eugene Mirman?

  Welcome to StarTalk Live! I'm Eugene Mirman. It is my great pleasure to bring on the amazing, the wonderful Neil deGrasse Tyson!

• 0:41Neil deGrasse Tyson?

  Dude.

• 0:46Neil deGrasse Tyson?

  Welcome to StarTalk. This is StarTalk Live. Tonight's topic is everything you ever wanted to know and perhaps never wanted to know about gravitational waves.

• 1:01Neil deGrasse Tyson?

  Moving through the universe.

• 1:05Neil deGrasse Tyson?

  Washing over Earth itself. Where'd they come from? How do we detect them? Who's doing the detecting? And what is the future of that exercise? And I have experts this evening to help us through. Give a nice, warm, New Jersey welcome to Janna Levin. Janna Levin, come on out. Janna Levin. There she goes. Jana, how you doing? She's professor of physics and astronomy at Barnard College and just came out with a book all about... What? Black holes?

• 1:40Janna Levin?

  Black hole... She's supposed to say it in a DJ voice. "Black Hole Blues and Other Songs From Outer Space."

• 1:49Neil deGrasse Tyson?

  This is "The Black Hole Blues and Other Songs From Outer Space." That is the title of her book!

• 1:58Neil deGrasse Tyson?

  We talk about black holes trying to talk to us.

• 2:00Speaker 03

  Yeah, they're saying it.

• 2:01Neil deGrasse Tyson?

  With their soundtrack.

• 2:02Speaker 03

  Yeah.

• 2:02Neil deGrasse Tyson?

  Okay, very cool. And so, not only that, someone who is an expert not only in cosmology and has written a book on this subject, we combed the land to find someone who actually worked at the facility, the Laser Interferometric Gravitational Wave Observatory, the actual place that made the discovery. Give a nice warm New Jersey welcome to Nerjes Mabalvala. Where is she? Here she goes.

• 2:36Neil deGrasse Tyson?

  She's a professor of physics at the Massachusetts Institute of Technology, and you worked on the actual facility, at the actual facility?

• 2:46Speaker 03

  I did, I did. I've been doing this for 25 years.

• 2:48Neil deGrasse Tyson?

  Yeah, okay. And did you start when you were eight or something? What, what, I mean?

• 2:53Speaker 03

  Before I was born.

• 2:54Neil deGrasse Tyson?

  Before you were born. That's how you start. You gotta start 'em early, people. So Eugene, who'd you bring today?

• 3:01Eugene Mirman?

  And today we have an amazing comedian, one of the writers or creators and stars of Wet Hot American Summer, Michael Showalter.

• 3:10Neil deGrasse Tyson?

  Michael.

• 3:17Eugene Mirman?

  New Jersey, Joe. Oh, you're sitting over there.

• 3:22Eugene Mirman?

  Welcome home.

• 3:23Speaker 04

  It's good to be home. Yes, I'm a Jersey boy, if that's what you mean, yes.

• 3:30Neil deGrasse Tyson?

  I gotta ask, what exit?

• 3:33Speaker 04

  Nine.

• 3:33Neil deGrasse Tyson?

  Nine, thank you.

• 3:34Speaker 04

  Exit nine.

• 3:34Neil deGrasse Tyson?

  Thank you. That's the exit one takes to get to Princeton, New Jersey.

• 3:37Speaker 04

  That's where I'm from, Princeton, New Jersey.

• 3:39Neil deGrasse Tyson?

  You are from Princeton, okay.

• 3:40Speaker 04

  Yes, yes.

• 3:41Neil deGrasse Tyson?

  It's cool. Just showing off some Jersey flu.

• 3:43Speaker 04

  I grew up on the mean streets of Princeton.

• 3:48Neil deGrasse Tyson?

  So, Nergis, tell us all what gravitational waves are. And in the green room, I call them gravity waves, and you said, "No, they're not gravity waves. They're gravitational waves." And that sounds kind of semantic to me, and I don't know what you're talking about.

• 4:01Speaker 03

  So, there's a big difference. Gravity waves are local to our Earth. They are actually waves, seismic waves. They're part of density movements in the Earth. Whereas gravitational waves are cosmic. They come to us from the universe.

• 4:13Neil deGrasse Tyson?

  You're telling me that the geologists got to the word "gravity waves" first?

• 4:17Speaker 03

  That's absolutely right. Although, actually, gravitational waves have been around for about 100 years in as gravitational waves. But I think the geologists probably had it "gravity" first.

• 4:26Neil deGrasse Tyson?

  Yeah, but the universe has been making gravitational waves for billions of years.

• 4:29Speaker 03

  Yes, right since its inception.

• 4:31Eugene Mirman?

  And the Earth's been doing it for a long time, too. You just noticed 100 years ago.

• 4:36Speaker 03

  To be fair...

• 4:38Neil deGrasse Tyson?

  No, you're not going to be fair to the geologists.

• 4:40Eugene Mirman?

  Gravity didn't start around the time they killed McKinley.

• 4:43Speaker 03

  It's true, but gravitational waves started at the very beginning of the universe. Gravity waves came about when the Earth was formed, so much later.

• 4:52Eugene Mirman?

  Okay, agreed.

• 4:53Speaker 03

  So, I think gravitational wave wins the race.

• 4:58Neil deGrasse Tyson?

  Yeah, yeah, okay. I will promise I'll say "gravitational wave," so we don't confuse the geologists in the audience.

• 5:03Speaker 03

  Okay.

• 5:04Eugene Mirman?

  Or the comedians.

• 5:07Neil deGrasse Tyson?

  Now, Jenna, I have some issues that I want to take up with you. You keep talking about waves. I get it, they're waves. But now you're talking about the blues, and music, and sound. And we knew from the movie Alien that no one can hear you scream in space. Actually, we knew it well before the movie. That's when it became a publicly- thing. So, why this urge to always analogize it to sound? I think that's misleading the public.

• 5:36Janna Levin?

  Yeah, it's actually stronger than an analogy. So, let's say two black holes collide. They actually cause...

• 5:44Neil deGrasse Tyson?

  Just for instance...

• 5:45Janna Levin?

  Just for instance.

• 5:46Neil deGrasse Tyson?

  Yeah.

• 5:47Janna Levin?

  This is the kind of thing, you know, we spend our energy on. And they will literally ripple the shape of spacetime. Spacetime around the black holes will squeeze and stretch and emanate outwards as a wave, like fish swirling on a pond. Or I prefer mallets on a drum and the drum rings. And so these waves emanate outwards. Now, if you were close enough to the black holes, even though it's empty space and there's no air, it's technically conceivable it would ring your eardrum and you would actually hear from the squeezing and stretching of your ear mechanism.

• 6:18Neil deGrasse Tyson?

  Of your cranium.

• 6:19Janna Levin?

  Well, no, if it squeezes your cranium, you're just gonna die.

• 6:22Eugene Mirman?

  Even if it squeezes it just a little bit?

• 6:26Janna Levin?

  Look, you don't want a sound to be so loud that it's squeezing your cranium.

• 6:30Neil deGrasse Tyson?

  Yeah.

• 6:31Janna Levin?

  So, but if it rings the eardrum mechanism, you would technically hear the black holes. And then you would die because you'd be too close to the collision of two black holes.

• 6:39Neil deGrasse Tyson?

  Right, you'd be excite, right, right, right.

• 6:40Eugene Mirman?

  If you hear a black hole...

• 6:41Janna Levin?

  Eventually you die.

• 6:42Eugene Mirman?

  That's... and is it like a sonic boom where you're like, "What's that?", and then you go back in time and explode?

• 6:47Janna Levin?

  I don't know what you're talking about. No, do you go back in time with sonic booms?

• 6:53Eugene Mirman?

  No, but you said that it ripples time-space and I thought maybe time would be affected.

• 6:58Janna Levin?

  Oh, I see what you're saying. Yeah, that's true. You're...

• 7:01Eugene Mirman?

  Ha ha!

• 7:02Janna Levin?

  Your time relative to somebody else's would be affected.

• 7:08Eugene Mirman?

  That's good enough.

• 7:09Neil deGrasse Tyson?

  All right, so, so Nirjas, you were part of the team that made a discovery.

• 7:16Speaker 03

  Yes.

• 7:17Neil deGrasse Tyson?

  And so, tell me about that discovery in particular.

• 7:21Speaker 03

  Okay, so...

• 7:22Neil deGrasse Tyson?

  It's recent, it's recent news.

• 7:23Speaker 03

  It's very recent, so I'll tell you the date.

• 7:25Neil deGrasse Tyson?

  Go for it.

• 7:27Speaker 03

  It was September 14th, 2015.

• 7:30Neil deGrasse Tyson?

  Okay.

• 7:31Speaker 03

  And our detectors began to sing, just as Jenna says. They, you know, we recorded a signal that we could turn into a sound, and it turned out to be the sounds of two black holes colliding, and...

• 7:44Neil deGrasse Tyson?

  Where?

• 7:45Speaker 03

  Quite far away, thankfully. Our eardrums would not ring from this because we were thankfully far away. 1.3 billion light-years away. So, quite far.

• 7:55Neil deGrasse Tyson?

  Okay, so...

• 7:57Eugene Mirman?

  How many, like, hours is that, just to get it?

• 7:59Neil deGrasse Tyson?

  So, what you're saying, so, wait, and how big were the black holes?

• 8:04Speaker 03

  So, the black holes were 30 times more massive than our sun. So, again, rather fat for those kinds of black holes.

• 8:12Neil deGrasse Tyson?

  Okay, so, it was two black holes, 30 times the mass of the sun, colliding 1.3 billion years ago, before the Cambrian explosion of life on Earth.

• 8:24Speaker 03

  Yes.

• 8:25Neil deGrasse Tyson?

  So, there were single-celled organisms swarming in tide pools, and that's when this event happened. And then this ripple moved through space. This disturbance in the fabric of spacetime propagated at the speed of light.

• 8:40Speaker 03

  Yep.

• 8:41Neil deGrasse Tyson?

  And it's been going for 1.3 billion years. And in the interim, life evolved to make vertebrates and primates and humans. And then humans developed civilization and agriculture and technology and physicists and Einstein and the prediction and LIGO, the experiment, and you. And then, you turn on the machine and you detect it.

• 9:06Speaker 03

  Yeah, that's about right. I do want to say it was me and a thousand other colleagues.

• 9:19Neil deGrasse Tyson?

  Okay, but we got you here now.

• 9:22Speaker 03

  Yes.

• 9:23Neil deGrasse Tyson?

  Okay.

• 9:24Speaker 03

  Tough luck.

• 9:25Neil deGrasse Tyson?

  What were you saying, Janice?

• 9:26Janna Levin?

  Well, I was just gonna say, it was when the discovery hit, the experimentalists like Nurgis were still doing tests on the instrument.

• 9:36Neil deGrasse Tyson?

  So, the theorists and the experimentalists?

• 9:37Janna Levin?

  Yeah.

• 9:38Neil deGrasse Tyson?

  Who, in an ideal world, they work together?

• 9:40Janna Levin?

  Yeah.

• 9:41Neil deGrasse Tyson?

  Okay.

• 9:42Janna Levin?

  That's an ideal world.

• 9:43Eugene Mirman?

  And are you guys in reality enemies?

• 9:45Janna Levin?

  Well, we're often sadly in reality a little disconnected. So the interesting thing for me writing the book was I became so enamored of the experimentalists and what they were doing. I mean, it's one thing to kind of pen and paper fantasize about black holes colliding. I was like, are you people seriously going to try to do this with like metal and glass? That's insane. And a lot of people thought they were insane. It was not a popular experiment. If you had asked people even in August, many people in astrophysics would have said, this isn't going to succeed. So it was really just a dramatic thing that happened that as soon as it went on, they weren't even ready, but as soon as it was on, bam.

• 10:23Neil deGrasse Tyson?

  Well, and when the news hit, it reached into pop culture. It was page one banner headlines. And in fact, there's a storage company in Manhattan, they're called Manhattan Mini Storage. And they have these clever ads on the sides of buildings. And I've got it written here. One of them said, scientists found gravity waves in outer space. If only were that easy to find in an apartment in New York with a walk-in closet. Rent your own personal closet space. Manhattan Mini Storage.

• 10:53Janna Levin?

  Did they pay you for that?

• 10:55Neil deGrasse Tyson?

  No, no, that was not an advertisement. So they went right in to fold in the discovery into pop culture. So I was very impressed by that. Did you have any clue it would be that popular?

• 11:05Speaker 03

  No, you know, I actually was pretty sure that the scientific community would be very excited by it, but I don't think almost any of us could have predicted how much it moved into, you know, how much it moved people who just like to see science succeed.

• 11:19Eugene Mirman?

  You don't have a machine that also detects how exciting certain breakthroughs will be to regular people?

• 11:23Speaker 03

  I'm working on it.

• 11:24Neil deGrasse Tyson?

  Yeah, so it's, so I mean, I was, I was impressed by it. I think people like big problems and cosmology and black holes. It had all the trappings of the news story that should make banner headlines. And you, when you were working on this, isn't it true that the discovery paper was published? When was the paper published?

• 11:47Speaker 03

  The paper was published on February 11th, 2016.

• 11:51Neil deGrasse Tyson?

  Okay, so there's a time delay between the detection and the paper. Why?

• 11:56Speaker 03

  It's a huge amount of work that had to be done. From the time our instruments recorded the signal to the time the paper was ready, here were the steps. We had to first make sure the signal was real. Because these detectors, I mean, the signal is really, really weak. And there's all kinds of other things that masquerade as signal in our detectors. We had to make sure the signal was real. We had to make sure it was from the universe and not from one of our colleagues injecting it into our detector, which sometimes happens. We do that to ourselves.

• 12:24Eugene Mirman?

  What does that mean?

• 12:25Speaker 03

  It's self-inflicted pain.

• 12:27Speaker 04

  Just like a scientist outside the microphone going, "Huh."

• 12:30Neil deGrasse Tyson?

  Which is coming.

• 12:32Eugene Mirman?

  So you might have just detected someone playing guitar.

• 12:36Speaker 03

  You could, but even more than that, it's self-inflicted pain in that we, the scientists, go into our own data and inject signals, fake signals, and then ask ourselves, could we find them? It's like playing hide and seek with yourself.

• 12:50Eugene Mirman?

  Yeah, it sounds normal. Now I get why if you ask people in August, they'd be like, "Those people are too good."

• 12:56Neil deGrasse Tyson?

  Okay, so you gotta make sure the signal is legit.

• 12:59Speaker 03

  That's right.

• 13:00Neil deGrasse Tyson?

  And then you publish, so the general public doesn't know until, didn't know until when?

• 13:06Speaker 03

  February 11th, when we announced it.

• 13:08Neil deGrasse Tyson?

  February 11th, okay. And just FYI, I visited one of the LIGO facilities after, apparently, they had already made the detection. Nobody spilled anything to me.

• 13:19Speaker 03

  There was no winks or nods.

• 13:22Neil deGrasse Tyson?

  No, no, they didn't wink. They were very smiley, though, I remember. Now, Janet, this search has been going on for decades.

• 13:28Speaker 03

  Yeah, for decades.

• 13:29Neil deGrasse Tyson?

  And you chronicle this in your book, don't you?

• 13:31Janna Levin?

  Yeah, so when I started becoming so enamored of the physicality of this machine that they were building, you know, these are huge machines. They're four kilometers long each, and there's two of them, one in Louisiana and one in Washington State. The first prototype was built by somebody named Ray Weiss from MIT, who's a colleague of Nergis's in the late 60s. And that's when it started. He dreamt up this idea of building it, and the first one that was built was like a meter and a half, you know? This is a guy on his own. And 50 years, people like Ray were working on this. And slowly, you know, Kip Thorne comes in and Ron Drever, and they're really just three of them.

• 14:09Neil deGrasse Tyson?

  Kip Thorne is a cosmologist at Caltech.

• 14:11Janna Levin?

  Yeah.

• 14:12Neil deGrasse Tyson?

  Perhaps in pop culture, best known for being a co-executive producer of the movie

• 14:18Neil deGrasse Tyson?

  Interstellar, yeah.

• 14:19Janna Levin?

  Yeah, so, right.

• 14:21Neil deGrasse Tyson?

  You got all the right people on it.

• 14:22Janna Levin?

  Yeah, you got the right people on it. So before Kip was a movie producer.

• 14:26Neil deGrasse Tyson?

  Okay, alright.

• 14:27Janna Levin?

  He was a very famous astrophysicist. So fifty years, they pushed through from a one and a half meter long instrument, finally realizing, you know, Ray says he finally realized one day that this had to be big. And now it's four kilometers long and they're in vacuum, which is just a very intense thing to do.

• 14:48Neil deGrasse Tyson?

  You vacuumed out a four kilometer long tube.

• 14:50Janna Levin?

  That's right. In 1998, the vacuums have been there for this instrument is when they pulled the vacuum. So if the vacuum had broken between 1998 and now, people said we all would have gone home. Like, that is an expensive and difficult procedure. So this was a really arduous climb for them.

• 15:09Neil deGrasse Tyson?

  So just to clarify, so the history of astrophysics probing the universe is one where we study light. Initially visible light, Roy G. Biv. You know Roy G. Biv? Yes, we know. You know Roy? Even I do. Yeah, yeah, yeah. Especially Biv. Red, orange, yellow, green, blue, indigo, violet, seven colors named by Isaac Newton, but there are many more colors than that. He had a mystical fascination with the number seven, so he just picked seven colors and attached it. So then we find out there's colors outside of that range, there's infrared, and ultraviolet, and X-rays, gamma rays, radio waves. And so that becomes modern astrophysics, and it's all forms of light.

• 15:51Neil deGrasse Tyson?

  And now you guys have come up with another kind of telescope to find another kind of wave in the universe, the gravity wave. And this is just a stunning fact, that we've opened up a whole new, the first ever discovered gravity wave. And so now, we're no longer restricted to light itself.

• 16:11Janna Levin?

  Yeah, that's right. Everything we've known about the universe, more or less, I mean, very nearly everything comes to us from light, since Galileo. We've made this silent movie of the universe through everything you've described, all those colors. When Nurgis and her colleagues are working on the instrument, in the control room, they're listening to it through a speaker system. This is not light, and what they recorded was not a picture. It's really something fundamentally different. It's like we've gotten the soundtrack.

• 16:36Neil deGrasse Tyson?

  So you're saying this thing sounds like something?

• 16:38Janna Levin?

  It does, and, you know, let me...

• 16:41Speaker 03

  And if we had pointed a telescope at those black holes, we would have seen nothing. Even a telescope that's beyond our imagination. The best telescope you could imagine probably would have seen nothing.

• 16:53Eugene Mirman?

  What if you had pointed a very powerful microphone?

• 16:57Janna Levin?

  That's what they did.

• 16:58Neil deGrasse Tyson?

  So I think we've got, we have that sound. We can play that sound.

• 17:02Eugene Mirman?

  We have the sound?

• 17:03Neil deGrasse Tyson?

  Yes, we have the power to play, to push a button and play the sound. Okay, can we get that?

• 17:22Neil deGrasse Tyson?

  I have no idea what that was.

• 17:25Eugene Mirman?

  I believe that was from the third episode of New Gen- Next Generation Star Trek.

• 17:29Neil deGrasse Tyson?

  Right, right. The sound of the engine in the background. Wait, wait, so what was that low rumble?

• 17:35Speaker 03

  So there's two versions of the sound that you heard there. The low rumble was the sound as we recorded it in our signal. So what we do is we record a signal, and that signal actually, you can make a graph of it on a computer, or you can actually port it out onto a loudspeaker and hear it. And that's what we just did. We turned the signal into a signal that the loudspeaker could play back. So the low rumble is actually just the hum of noise in the detector, and superposed on that was the sound of these two black holes colliding. Now, if there were no noise, and if these were black holes that fit my voice range, they would have sounded like this. It would have been a low rumble that gets to a higher frequency and higher amplitude. It's a gone "whoop", and at the end, they would have collided.

• 18:20Speaker 03

  That end "whoop" would have been the colliding. So what we heard there initially was just the original sound, and they sound like a thump. It was "shh".

• 18:28Neil deGrasse Tyson?

  Did you just imitate two black holes colliding?

• 18:30Speaker 03

  I just did. I was expecting applause.

• 18:33Neil deGrasse Tyson?

  Took me a second to figure that out.

• 18:46Speaker 04

  I have a question, which is, and this is a very stupid question. This happened billions of years ago?

• 18:54Janna Levin?

  1.3, or so.

• 18:55Speaker 04

  150 billion?

• 18:56Eugene Mirman?

  No, 1.3 billion years ago.

• 18:58Janna Levin?

  Give or take a couple hundred million. Give or take a couple hundred million.

• 19:02Speaker 04

  So, how then do you know that it was black holes colliding and not anything else colliding?

• 19:07Eugene Mirman?

  In fact, you out there in space going, "Bloo, bloo, bloo, bloo."

• 19:11Speaker 04

  Like, how, if this happened so long ago, how can you be so sure that it was black holes?

• 19:18Neil deGrasse Tyson?

  Yeah.

• 19:18Speaker 03

  Yes, alright. It's a good question. So, Einstein 100 years ago gave us a theory of gravity in which you could start to predict what signals from black holes could look like. And in fact, Joanna has spent much of her career solving those equations that Einstein gave us and predicting what the signal from black holes should look like. And that signal looks different than signals from other kinds of stars, so...

• 19:46Neil deGrasse Tyson?

  Just if I can add there, so Einstein lays down the theoretical framework from which you can derive predictions for all manner of things. And that is a testament to the potency of what he laid to track 100 years ago. So, continue, yeah.

• 19:59Speaker 03

  Yes, and so maybe, Joanna, you want to say a little bit about what the signals would look like, you actually calculate them?

• 20:05Janna Levin?

  I think one of the ways to answer that question is, let's say you heard a ringing drum. You would be able to reconstruct technically from the sound of that drum how the mallets were moving. And so the black holes are the mallets in this example. And you can tell, if you're listening to an orchestra or you're listening to a band, how they're hitting the drum. And so if we're able to correctly predict from Einstein's theory the motions of the black holes, which we can do in great detail, and we can then predict how the drum rings, we actually can reconstruct the source from the sound.

• 20:38Neil deGrasse Tyson?

  Yeah, I just realized, we're talking like everybody knows what a black hole is. But let's just make sure we're on the same page.

• 20:44Eugene Mirman?

  Sure.

• 20:45Neil deGrasse Tyson?

  Tell us, Joanna.

• 20:46Janna Levin?

  So, a black hole is the death state of a very massive star, but we think of it as a thing, and I really would like to convince people it's not actually a thing. After the star collapses, what it does is it curves spacetime so strongly around it that not even light can escape. That's the famous saying about the black hole. And then, the material in the star keeps falling. So if you go up to the shadow of the black hole, and it's a shadow because no light can escape, there's nothing there. The black hole is not a hot, dense object. It's actually a curvature in spacetime. It's completely dark. The stuff that made it is gone. If you want to find out where it went, you have to go in too.

• 21:26Eugene Mirman?

  Does it move around, or is it there?

• 21:29Janna Levin?

  The black hole moves around like any other object, but it's kind of like a place.

• 21:34Eugene Mirman?

  Does it go far? Like, will it come and...does it eat planets?

• 21:36Janna Levin?

  We are orbiting a supermassive black hole in the center of our own galaxy, and we are technically falling into it, but I-

• 21:44Eugene Mirman?

  How slowly? Like, how worried should I be?

• 21:45Janna Levin?

  Yeah.

• 21:46Speaker 04

  Is it really cold inside a black hole?

• 21:50Janna Levin?

  That's an interesting question.

• 21:51Speaker 04

  Do you have to wear, like, a sweater?

• 21:53Janna Levin?

  Yeah. It is probably deathly cold. Yeah, but it's not dark inside the black hole, because the light from the universe can fall in behind you, and you can see it. It's only dark outside the black hole. Black holes are dark on the outside, not on the inside.

• 22:07Neil deGrasse Tyson?

  Plus, to be clear, when we use the word "hole" in modern, in everyday parlance, it's like something you fall through, and then you just fall through. Whereas, a black hole is a hole in every direction that you approach it.

• 22:21Janna Levin?

  It's a spherical hole. It's a spherical hole.

• 22:24Neil deGrasse Tyson?

  So you can fall into this hole no matter which way you approach it?

• 22:27Janna Levin?

  Yes. You would approach this region, this spherical region, where you'd have to travel faster than the speed of light to escape. So you have no choice, once you hit that sphere, but to fall forward. In fact, it's almost like you're falling towards the future, because space and time sort of switch places. I'm not making this stuff up.

• 22:45Neil deGrasse Tyson?

  Is there...

• 22:46Janna Levin?

  I'm not making this stuff up.

• 22:49Speaker 04

  I'm not making this stuff up.

• 22:51Janna Levin?

  Space and time switch places inside the black hole, so that you're forced toward-

• 22:54Neil deGrasse Tyson?

  Wait, don't just say that and don't explain it.

• 22:56Eugene Mirman?

  Yeah, no, we get it. It's the way to go into the future. No problem. Next.

• 22:59Neil deGrasse Tyson?

  Yeah, I know. Yeah, we got that. Next? Yeah, what? No.

• 23:03Janna Levin?

  Well, here's how I can...you want me to really explain that? I can try that. Okay, no. You want to go? We can go forward.

• 23:08Eugene Mirman?

  No, no, we want to know. I was kidding about that. We don't want to know how time travel in a black hole works.

• 23:13Neil deGrasse Tyson?

  Wait, wait, wait. So famously, Matthew McConaughey went into a black hole in-

• 23:18Speaker 04

  In his career?

• 23:25Neil deGrasse Tyson?

  In Interstellar.

• 23:30Speaker 04

  Oh, oh, oh.

• 23:30Neil deGrasse Tyson?

  And so, so they portrayed that he had some kind of access to the timeline of his life.

• 23:37Janna Levin?

  Yeah.

• 23:37Neil deGrasse Tyson?

  And so, I don't know, was that sort of, was that because we really don't know, so make stuff up?

• 23:43Janna Levin?

  Yeah.

• 23:44Neil deGrasse Tyson?

  Or is your, yeah, okay, or is your space and time switching empower that?

• 23:49Janna Levin?

  I don't think the space and time switching empowers it, but I can say this much, the black hole, however big it is on the outside, can be very deceptive about what's on the inside. The black hole can be much bigger on the inside than it is on the outside.

• 24:01Eugene Mirman?

  Really?

• 24:02Janna Levin?

  Yeah, like a TARDIS, like in Doctor Who.

• 24:05Neil deGrasse Tyson?

  Oh, my gosh.

• 24:06Eugene Mirman?

  Like a TARDIS. So the TARDIS is, wait, so how, like, what's the?

• 24:10Neil deGrasse Tyson?

  Wait, wait, and for those who don't know the TARDIS reference, it's like-

• 24:13Eugene Mirman?

  Get out!

• 24:16Neil deGrasse Tyson?

  Wait, wait, no, there are other references. Ready? Wait, wait, it's like, it's like, um, Mary Poppins' carry bag.

• 24:27Janna Levin?

  Very good.

• 24:29Neil deGrasse Tyson?

  Does she pull a whole plant out of the bag? And pulls it like a, okay. That's just evidence that Mary Poppins is herself.

• 24:36Speaker 04

  Wait, that's a, did you just describe a black hole?

• 24:39Neil deGrasse Tyson?

  I described, uh, something that's bigger on the inside than on the outside. But it was her ba, it's her bag, yeah. Okay, so thanks for that, that mini tutorial on black hole, on black holes. Uh, we'll figure out how to invoke them.

• 24:54Eugene Mirman?

  I'm really gonna start working on this for real now.

• 24:58Neil deGrasse Tyson?

  Did I interrupt you a second ago? Or were you?

• 25:00Speaker 04

  I don't think so, I mean, I was, it's just all very confusing. There was a moment in my life where I like, people would say like, how good Radiohead is, and I would be, and I didn't understand, but then I got it.

• 25:15Speaker 04

  And I wanna know, I wanna know, was there ever a moment where you didn't understand what a black hole was, and then all of a sudden you go, oh, I get it now? And will that moment ever occur for me?

• 25:34Janna Levin?

  I'm only gonna answer the first question.

• 25:38Janna Levin?

  No, so I, before I started studying the mathematics of it, was frustrated too, because you're just taking somebody's word for it, and they're just saying these crazy, insane things that are, seem so implausible. And whenever we get crazy letters from people, it's usually just stringing together words like this, that sound kinda fancy. But if you take the mathematics of Einstein's theory of curved spacetime, you start, and you just really spent a lot of your energy on it.

• 26:06Speaker 04

  So it wasn't an aha moment? It wasn't just a, "Oh, I get it."

• 26:10Janna Levin?

  No, it's a long process, no. And it's very, and it's spectacular. I really think of my life as before I spoke general relativity, and after.

• 26:18Speaker 04

  I'm the same way.

• 26:22Speaker 04

  I'm doing the before phase.

• 26:23Neil deGrasse Tyson?

  Yeah, you have to earn your fluency.

• 26:25Janna Levin?

  Yes, yes, absolutely.

• 26:27Neil deGrasse Tyson?

  Okay, you too, Nurgis? You have to earn your fluency?

• 26:29Speaker 03

  Yes, and you know, the story's not over yet. I don't think we fully know what happens inside of black holes. We don't know how to explain the singularity. We have ideas, but any one of them could be true, so...

• 26:41Eugene Mirman?

  What are like, just six of them?

• 26:44Speaker 03

  Well, the one, the one...

• 26:45Eugene Mirman?

  What's the most popular?

• 26:46Speaker 04

  What's singularity?

• 26:47Speaker 03

  Ah, the singularity, oh my goodness. It's a point in space that's smaller than a point.

• 26:55Janna Levin?

  Get it?

• 26:56Speaker 03

  Can't you see?

• 26:58Neil deGrasse Tyson?

  Stupid.

• 27:01Neil deGrasse Tyson?

  Such a stupid point. Everybody knew that.

• 27:04Speaker 04

  No, but in all seriousness, could you somehow connect it to Mary Poppins' handbag?

• 27:10Speaker 03

  I think there was a singularity in there. What do you think?

• 27:13Neil deGrasse Tyson?

  At least she had access to a higher dimension.

• 27:15Speaker 03

  That's right.

• 27:18Neil deGrasse Tyson?

  Before we go to our first break, let me just clarify something about the detection, the LIGO detection. The, as I understand it, you turned on the machine to start taking data, and within a week, you got the first detection?

• 27:38Speaker 03

  Yeah, actually, less than a week, it's true.

• 27:41Neil deGrasse Tyson?

  And how much time?

• 27:42Speaker 03

  About two days.

• 27:43Neil deGrasse Tyson?

  We've been two days!

• 27:44Speaker 03

  You know, it...

• 27:45Neil deGrasse Tyson?

  We've been trying fifty years to detect gravity waves.

• 27:48Janna Levin?

  Hey, I haven't been trying for fifty years! Give me a minute!

• 27:53Neil deGrasse Tyson?

  We've tried fifty years to detect gravity waves, and a wave born 1.3 billion light-years away, traveling for 1.3 billion years, you flick the switch and you detect it two days later?

• 28:06Speaker 03

  Yes!

• 28:07Janna Levin?

  Okay, then...

• 28:08Eugene Mirman?

  She's cocky about it. Have you detected more since then?

• 28:12Speaker 03

  So, we've certainly seen some small... evidence of smaller black holes than these, the two that we're describing. And there's more data in the can that we're still analyzing, so probably there's more there, maybe not.

• 28:25Eugene Mirman?

  That would be amazing if you turn... if it's like a fluke that you found it.

• 28:28Speaker 03

  No, so I think, I think there's... it's not just pure fluke. I mean, we turned on this machine after a major upgrade. It was down for four years after the first phase, and it had quite a bit more sensitivity, particularly in certain frequency bands where you shouldn't detect such signals. So I don't think it's a total fluke that we turned it on and we'd never seen these before and suddenly we did. We've made a machine we'd never made before! You know, it was a damn good machine!

• 28:58Neil deGrasse Tyson?

  Okay. She said "damn."

• 29:03Neil deGrasse Tyson?

  We'll have to bleep that on...

• 29:06Eugene Mirman?

  We made a damn good machine.

• 29:08Neil deGrasse Tyson?

  No, but my issue is not that you detected it in two days, but that... doesn't it tell us that thirty solar-mass black holes are colliding every couple of days somewhere in the universe?

• 29:23Speaker 03

  It should tell us that if we see enough of them over some observing period. So, yes, you don't expect them to be at completely... at even time spacings, right?

• 29:35Neil deGrasse Tyson?

  Of course not.

• 29:36Speaker 03

  They come sort of every now and then.

• 29:37Neil deGrasse Tyson?

  I'm just saying, after fifty years you turn it on, you detect it in two days, this stuff is going on all the time, as far as I'm concerned.

• 29:42Speaker 03

  Yes, yes, I agree. I think, I think anybody...

• 29:44Eugene Mirman?

  Just nobody talks about it.

• 29:49Neil deGrasse Tyson?

  Okay.

• 29:50Janna Levin?

  Yes.

• 29:50Neil deGrasse Tyson?

  Okay, so we agree on that?

• 29:52Janna Levin?

  Yes, we do.

• 29:52Neil deGrasse Tyson?

  This has got to be a way more common phenomenon than people had imagined previously.

• 29:56Janna Levin?

  Yes.

• 29:57Neil deGrasse Tyson?

  Okay, cool. Well, after the break, we'll find out more about the people behind LIGO and the incredible 50-year quest that led to this amazing discovery on StarTalk!

• 30:19Neil deGrasse Tyson?

  Cool!

• 30:30Neil deGrasse Tyson?

  We're live at the Count Basie Theater in New Jersey. This is StarTalk!

• 30:40Neil deGrasse Tyson?

  We're talking about gravitational waves propagating through the cosmos. And Jana, your book, you started this book not knowing that they were about to make a discovery.

• 30:52Janna Levin?

  Yeah.

• 30:52Neil deGrasse Tyson?

  And then they made a discovery.

• 30:53Janna Levin?

  Yeah.

• 30:54Neil deGrasse Tyson?

  So, did you have to like change up your plans?

• 30:56Janna Levin?

  Yeah. Well, actually, I was two years late on delivering this book, which was perfect.

• 31:05Neil deGrasse Tyson?

  Oh, okay.

• 31:06Janna Levin?

  It dovetailed, like, I printed the book out for Ray Weiss, one of the original architects, and Kip Thorne, who we've talked about. I printed a copy for each of them on September 14th, just by coincidence.

• 31:18Neil deGrasse Tyson?

  Whoa.

• 31:18Janna Levin?

  And sent them drafts. And I remember Ray was kind of getting agitated, and he's like, "What are you gonna do if there's a discovery?"

• 31:25Neil deGrasse Tyson?

  (laughing)

• 31:26Janna Levin?

  But, you know, he's not allowed to tell me. So, I loved that I could write the book without knowing if they succeeded, because the book is really about the campaign. It's really about the tension. I mean, even in the close of the book, Ray's saying things like, "If this doesn't detect black holes, the thing is a failure." And that's an incredibly bold thing to say in August 2015, from the original designer of the machine. And so, so...

• 31:54Neil deGrasse Tyson?

  So, was it this...

• 31:55Janna Levin?

  But I got to write an epilogue. Of redemption, you know, and so, so they included me in the discovery a few months earlier and Nurgis was telling me on the way over that there was a lot of discussion about when they could tell me, which is really, really sweet. So before, before I went to press, they gave me the chance to write the epilogue. So I kind of love it because the book is as though you don't know the conclusion until you actually get to the close of the story.

• 32:21Neil deGrasse Tyson?

  And so, how much money's been spent to make this happen?

• 32:23Janna Levin?

  About a billion dollars integrated, the experiment costs.

• 32:28Neil deGrasse Tyson?

  Okay, so, a billion, we've got to say it in a Carl Sagan way, a billion dollars.

• 32:35Janna Levin?

  A billion dollars. It's a lot of dollars to say at the end of the story if we don't discover black holes, if things are failure.

• 32:41Eugene Mirman?

  Does it end with, "Imagine how many pants we could have bought."

• 32:45Neil deGrasse Tyson?

  So, so, as we said earlier, Albert Einstein, I, I, you, you said he came up with his general relativity 100 years ago, but I didn't see anybody talk about at the time, and I've been screaming loudly, that Einstein also laid the foundation for the laser, which is a fundamental part of the technology of LIGO. Could you tell me how you're using lasers?

• 33:12Speaker 03

  Yeah, so it's the L in LIGO, it's laser.

• 33:15Neil deGrasse Tyson?

  Yeah.

• 33:15Speaker 03

  Yep. So, the, that was, you know, if, if you ask, why was it that, I mean Einstein made this prediction 100 years ago, why was it in the 1960s, in the late 1960s, that Ray Weiss came up, and others, but he came up with sort of designing this instrument that could measure, it was the invention of the laser. In 1960, the laser was invented. In 68, Weiss had started to think about using it. And the laser is, is our, is fundamentally our first foray into quantum light. And Einstein

• 33:48Speaker 03

  Sort of laid some of the groundwork for quantizing light. So I think it's very incredible that he gave us not just his theory of gravity, he also gave us some foundational ideas for making lasers.

• 34:02Neil deGrasse Tyson?

  So Einstein laid down general theory of relativity, which predicts the existence of gravity waves. It predicted, later discovered, the existence of black holes. He then lays down the theoretical construct for lasers. Then, a hundred years later, you use lasers to detect gravity waves that had just been emitted by two colliding black holes.

• 34:26Speaker 03

  Yes.

• 34:27Neil deGrasse Tyson?

  So that tells me Einstein is just the bad-assest person there ever was.

• 34:33Speaker 03

  He's the man.

• 34:35Neil deGrasse Tyson?

  I mean, think about that.

• 34:40Janna Levin?

  But just so you know, it wasn't easy for Einstein to do all of this. He kept changing his mind about whether or not gravitational waves are real. So he would write papers saying they were real, write papers saying they weren't real.

• 34:52Neil deGrasse Tyson?

  That'd be right no matter what.

• 34:53Janna Levin?

  Yeah.

• 34:55Neil deGrasse Tyson?

  I take it back what I said about Einstein.

• 34:57Janna Levin?

  It went on for decades, and at one point, he would write a paper saying gravitational waves don't exist. It would get accepted for publication, and he'd slip in a paper that said that they did. Like, right when it went to press. So it was such a hard problem. And somebody once said, "Einstein, your name's gonna be on this paper. You have to be very careful not to put your name on a wrong paper." And he thought that was hysterical. He said, "My name is on plenty of wrong papers."

• 35:22Speaker 03

  So he wasn't afraid to be wrong.

• 35:23Neil deGrasse Tyson?

  I wish my name were on as many wrong papers as his.

• 35:27Neil deGrasse Tyson?

  So who are some of the key... So you mentioned Ray Weiss and Kip Thorne, we've heard. And who else are key early players?

• 35:33Speaker 03

  So I think, as Jana's book tells us, the troika originally was Kip Thorne, who was thinking about the theory and the astrophysics. How do you model signals of black holes or neutron stars that are orbiting and colliding into each other?

• 35:49Neil deGrasse Tyson?

  Oh, by the way, in the movie Interstellar, co-executive produced by Kip Thorne, the name of one of the robots is Kip.

• 35:59Eugene Mirman?

  That's what money gets you.

• 36:00Neil deGrasse Tyson?

  I'm just saying. I'm just saying. Okay, go on, I interrupted.

• 36:04Speaker 03

  So, and then, so that was Skip thinking about sources and theory. There was Ray Wise who came up with the idea of using an interferometer. And actually, more importantly, I mean, that idea had been around at about the same time.

• 36:18Eugene Mirman?

  What is that?

• 36:19Speaker 03

  An interferometer. An interferometer is, is an optical device where you take a laser beam and you kind of split it in two pads.

• 36:25Eugene Mirman?

  Nice.

• 36:26Speaker 03

  And the light travels along two pads. And it comes back.

• 36:29Eugene Mirman?

  Nice.

• 36:30Speaker 03

  And then it interferes.

• 36:32Neil deGrasse Tyson?

  You can save your emotions for after she finishes.

• 36:34Eugene Mirman?

  So you start with a laser, you break it up, you get them back together.

• 36:37Speaker 03

  Yep.

• 36:38Eugene Mirman?

  And then you're like, now I get how gravity works.

• 36:40Speaker 03

  But along the way, what happened, when you broke the two laser beams apart, if they travel different distances, then when they come back together, they act a little funny. They're a bit darker or a bit brighter.

• 36:51Eugene Mirman?

  And why do they travel a different distance?

• 36:53Speaker 03

  Because the gravitational wave came through the detector.

• 36:56Eugene Mirman?

  Ah ha! I caught you! Now I get it.

• 37:01Neil deGrasse Tyson?

  Right. So what you have, so your two beams are otherwise identically the same length.

• 37:06Speaker 03

  Yes.

• 37:07Neil deGrasse Tyson?

  Now, now a gravity wave washes across the detector and makes the length of one different from the length of the other.

• 37:15Eugene Mirman?

  Because it went into the future.

• 37:17Neil deGrasse Tyson?

  And then you can recombine the waves, and now you have like a crest adding to a trough of these waves, and they interfere with one another. And you can measure this.

• 37:27Speaker 03

  We can measure that, and we can measure not just if crests line up with crests or crests line up with troughs, but lots of variations in between. So is it perfectly dark because troughs and troughs lined up, or is it perfectly bright or something in between? And that's how we make the measurement. We actually use the laser beam along one arm as a kind of a reference for measuring the light travel time along the other arm. You just compare, how long did the light take along this arm compared to the light along the perpendicular arm?

• 37:55Neil deGrasse Tyson?

  Now you've got two of these facilities. Why?

• 37:57Speaker 03

  Well, that's really important, because the...

• 38:01Neil deGrasse Tyson?

  And one is in Louisiana, one is in Washington State.

• 38:03Speaker 03

  State, yep. Yeah, so they're about 3,000 kilometers apart, and then there's...

• 38:07Neil deGrasse Tyson?

  Convert that to miles here for, because we're Americans here.

• 38:09Eugene Mirman?

  Eight. Eight miles. Trust me.

• 38:19Neil deGrasse Tyson?

  So it's about, it's about 2,000 miles.

• 38:21Speaker 03

  Yes, thereabouts.

• 38:22Neil deGrasse Tyson?

  You say 2,000, okay.

• 38:24Speaker 03

  So, so why do we need two of them? In fact, there's actually a European detector in Italy as well, Garbirgo. And why do we need so many? So a couple of things. One is the signals are very weak. And so how does this, can I say how the detector works?

• 38:39Neil deGrasse Tyson?

  Yeah.

• 38:40Speaker 03

  Do you want to know how the detector works?

• 38:44Speaker 03

  Okay.

• 38:44Neil deGrasse Tyson?

  They all get up and leave. No!

• 38:47Speaker 03

  Wait, wait, stop! I'll stop!

• 38:50Neil deGrasse Tyson?

  Okay, as they start going for the exits. Yeah, we love to know how it works.

• 38:53Speaker 03

  So the way it actually works is that the gravitational wave comes through the detector. It actually changes the distance between the laser and a mirror. That in our case, in the case of LIGO, the US detectors, the mirrors and the lasers are separated by 4 kilometers. So 2 and 1/2 miles. Okay? So, and, and what happens then is that our job then is simply to measure the change in distance between the laser and the mirror when the gravitational wave goes by compared to when it's not there. And now the problem is that the motion of these mirrors compared to the laser distance is tiny. The gravitational wave is really, really, really weak.

• 39:36Speaker 03

  And so the motion we're trying to measure over those 2 and 1/2 miles is smaller than 1,000th the size of a proton. Okay, so it's a very small number. It's 10 to the minus 18 meters for those of you who think in, in, in those kinds of numbers. Scientific notation. But really, what you have to think about is that you start off with an atom and you, you know, you get to something that's 1,000 times smaller than the typical size of an atom. You have its nucleus in the center, a proton. And now we're thinking of something that's 1,000 times smaller than the central nucleus of an atom. So it's a small number. We measured that.

• 40:13Neil deGrasse Tyson?

  So you claim.

• 40:14Speaker 03

  Yes.

• 40:16Speaker 04

  Did you measure it with like one of those rulers you get at Staples?

• 40:20Speaker 03

  Yes.

• 40:21Neil deGrasse Tyson?

  And then at the end, they put a ruler on it.

• 40:25Speaker 04

  The little wooden ruler?

• 40:27Eugene Mirman?

  No, it's more like one of the wheels that you use to measure like more like the street.

• 40:31Speaker 03

  No, we measured that using the travel time of the laser. That's why the laser is so important.

• 40:36Neil deGrasse Tyson?

  Okay, but you have two facilities.

• 40:38Speaker 03

  Yes, so, so, so why? Because this effect is so small. Now, we're trying to measure these tiny motions of mirrors and everything on our planet wants to move those mirrors by more than this passing gravitational wave.

• 40:49Neil deGrasse Tyson?

  I remember when I visited one of the facilities, you come near the, the beam, it says, "Drive really slowly" towards the facility, because anything is going to jiggle, shake and bake your experiment.

• 40:59Speaker 03

  Absolutely. And so that's...

• 41:00Neil deGrasse Tyson?

  So how do you know you didn't detect me driving into the facility?

• 41:02Speaker 03

  That's why we have two, because there's not two of you at, you know, 3,000 kilometers apart, by, by the same time.

• 41:09Neil deGrasse Tyson?

  How do you know?

• 41:11Eugene Mirman?

  Or how do you know that there isn't another car with another person?

• 41:14Speaker 03

  So, so the way that you know is that the, the detectors, the two observa-, at the two observatories are instrumented with all kinds of other instrumentation like seismometers that would measure you going by. And so we take those, we can remove those events from our signals. And now what happens, so think about the black holes we did detect. What we saw was a signal that arrived in our Louisiana detector first, and then seven milliseconds later, that same set of wiggles and bumps, that same signal...

• 41:44Neil deGrasse Tyson?

  So seven thousandths of a second?

• 41:45Speaker 03

  Yes, seven thousandths of a second later, it arrives at our Washington detector. And that told us something very important. It told us that the wave was coming in from the south, traveled through the Louisiana detector, and then continued on its way and seven milliseconds later, which is about the light travel time, this, you know, these waves also go at the speed of light, and it registered in the, in the Washington detector.

• 42:07Neil deGrasse Tyson?

  So it's not like a thing moving through the air, it is the rippling of the fabric of spacetime, shaking and baking Earth, being felt by one detector seven milliseconds after the other.

• 42:16Speaker 03

  Yes, that was, that was what it was. And that's what those two detectors are for.

• 42:23Speaker 04

  When, when you turned on the machine and you heard the signal, and, and you were like, "That's the real signal," did you guys then have a party?

• 42:34Speaker 03

  Yeah, so when, you know, in part because of the history of false starts in the field, many of us also have the psychology of, oh no, that can't be real. So we looked at this beautiful signal and we were trying to talk ourselves out of it. But eventually, after we did enough testing, it was real.

• 42:52Neil deGrasse Tyson?

  And realized it wasn't me driving down the street.

• 42:54Speaker 04

  Did everyone get drunk at the party?

• 42:57Eugene Mirman?

  But, but, um... Did you all have to come home drunk and go like, "No reason"?

• 43:04Neil deGrasse Tyson?

  Because the discovery paper has a thousand people on it. How are a thousand people gonna keep a secret?

• 43:09Speaker 04

  Huge party.

• 43:10Speaker 03

  We did pretty well, not perfectly, but pretty well.

• 43:12Neil deGrasse Tyson?

  You did damn well. I'm there and they're all just smiling ear to ear and nobody told me a damn thing.

• 43:18Speaker 04

  And what percentage sure were you that you were gonna hear the signal?

• 43:23Speaker 03

  Yeah, so there's a real mathematical process by which you can ascribe a number to how sure you were. And in the case of this signal, it was, we were sure at the level of one in 200,000 years. Now, what does that mean? It means if we, if, if we ran our, our experiment for 200,000 years, there was a chance of one, um, once in those 200,000 years, getting a signal that was like this.

• 43:48Neil deGrasse Tyson?

  Getting a random signal.

• 43:49Speaker 03

  Just from the noise of the detector.

• 43:51Speaker 04

  But then doesn't, but then you got it in less than a week.

• 43:53Janna Levin?

  No, uh, yeah, well, but the actual, you mean a false detection is what you're talking about?

• 43:58Speaker 03

  That's right. So what's, you know, what's the confidence then in, in the signal? How?

• 44:02Janna Levin?

  Right, so I think, I think what Nergis is saying, look, the chances that that was just false, that the two detectors just happened to ring like that, which is kind of related to what a meals...

• 44:11Speaker 04

  Was one in 200,000 years?

• 44:12Janna Levin?

  Yes.

• 44:12Speaker 04

  Oh, so that, okay, not the opposite.

• 44:14Janna Levin?

  No, but the sig, the prediction for how often do two black holes that big collide? The predictions were, were almost, were from like zero...

• 44:23Speaker 04

  But I'm saying, before you turned it on, you're like, "We're gonna hear a signal."

• 44:27Janna Levin?

  Not necessarily from two black holes. The predictions were zero to maybe a few per year, meaning that was our range of guessing.

• 44:36Neil deGrasse Tyson?

  Okay, so your predictions were wrong.

• 44:37Janna Levin?

  It, it literally could have been zero, yes.

• 44:40Neil deGrasse Tyson?

  But it wasn't, and so your predictions were wrong.

• 44:41Janna Levin?

  Well, it's helping, now we've done real astronomy.

• 44:43Neil deGrasse Tyson?

  Your theory's here, just tell me your predictions were wrong.

• 44:45Janna Levin?

  Yeah, I don't do that kind of theory, man.

• 44:48Neil deGrasse Tyson?

  Now she's, now the disclaimer, I don't do that.

• 44:51Janna Levin?

  I don't, no, honestly, that was saying we have some uncertainty in how stars are forming, how many of them are very, that big, and how many of them are in galaxies, and so that gives us an uncertainty, and the range of uncertainty was from like zero to thousand.

• 45:03Neil deGrasse Tyson?

  Oh, and two fits, one in two days, fits in there.

• 45:06Janna Levin?

  Per year, I'm saying, right, right, right.

• 45:07Neil deGrasse Tyson?

  So, so just before we go to our next break, Nurgus, what would you say was the biggest challenge over those years for LIGO? Was it just funding? Was it the engineering? Because you, you're predicting you're going to detect something with engineering that was not yet invented. That's got, that takes gonads.

• 45:22Speaker 03

  I, I think the biggest...

• 45:26Neil deGrasse Tyson?

  That's the gender neutral.

• 45:27Janna Levin?

  Is it? I don't think so.

• 45:30Neil deGrasse Tyson?

  Yeah, it's totally gender neutral, I think. I've been working on my gender neutral vocabulary. I don't get credit for that. It takes gonads, alright.

• 45:39Speaker 03

  Okay, so I think the, the most, different people will give you different answers. The most difficult thing was getting the, the instruments to be as sensitive as, as you could make them. And why is that so important? Because there was a huge amount of uncertainty, as Jana said, in the predictions of what was out in the sky, what would we see? So the only thing we really had control over was how good of an instrument can you make? Because nature gives you what she does, and the better the instrument, the more likely you were to see something on the low end of those predictions. So I think just pushing on to getting better and better sensitivity was one of the hardest things to keep doing.

• 46:17Neil deGrasse Tyson?

  So while this is just getting all the attention, where are the engineers?

• 46:20Speaker 03

  Oh, I mean, of those thousand co-authors on the paper, I would say a good quarter are, are engineers.

• 46:26Neil deGrasse Tyson?

  Quarter engineers.

• 46:27Janna Levin?

  And I just want to add, you know, we say, oh, they just turned it on and in a couple of days, that's, you know, a little misleading. So, the first generation of instruments was built in 2000, and those didn't hear anything. So there was an, LIGO has existed since then, and this is the second generation of machines. So they left this vacuum along the four kilometer long arms, but they replaced the components into a more advanced machine. So technically, this is advanced LIGO, it's a, it's a different machine. So they ran it for 15 years. Well, it wasn't quite 15. When did it turn off?

• 46:59Speaker 03

  So it, from 2000 to 2010, we ran what was called initial LIGO, the first phase.

• 47:05Neil deGrasse Tyson?

  Okay, so what it means is your detection levels in that 10 years were, nothing happened in the universe strong enough for you to detect in those 10 years.

• 47:13Speaker 03

  That's correct.

• 47:14Janna Levin?

  And the instrument wasn't sensitive enough?

• 47:16Speaker 03

  It wasn't 10 years of data. It was 10 years of operating, but probably two, between two and three years of data collected, because we would take long breaks to make improvements to the instrument.

• 47:26Neil deGrasse Tyson?

  Okay. So, okay.

• 47:28Janna Levin?

  So it was turning on advanced LIGO, and you could feel it as I was on the ground at the sites, visiting. You could feel that it was going really fast. You could feel it was going really well, that this, this was a new, you could tell a lot of people had cut their teeth on the first instrument. And so this second instrument, you just had this sense that it was happening fast. But I want to clarify that all the experimentalists told me, don't expect anything until 2018. And they, they really, the people who were telling me this really believed, don't expect anything till 2018. So it was a surprise. It went on, and it hit.

• 47:58Neil deGrasse Tyson?

  We'll talk about how the detection of gravity waves launches an entire new era of astrophysics, and of course, it opens a new window.

• 48:10Neil deGrasse Tyson?

  On StarTalk.