Cosmic Queries – Cosmic Collisions

What happens when two galaxies collide? On this episode, Neil deGrasse Tyson and comic cohost Chuck Nice answer questions about explosions, asteroids, quarks, and all things that go BOOM. Was our Big Bang someone elses Big Rip?

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

• 0:01Neil deGrasse Tyson?

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

• 0:14Neil deGrasse Tyson?

  This is StarTalk, Cosmic Queries Edition. Neil deGrasse Tyson, your personal astrophysicist, with Chuck Nice, Chuck Baby, my co-host.

• 0:23Chuck Nice?

  Hey Neil, what's happening?

• 0:25Neil deGrasse Tyson?

  Yeah, yeah, and on your resume now it starts saying Chuck Nice, actor, in addition to comedian. What's up with that?

• 0:33Chuck Nice?

  Well, I just figured, what the hell, put it on my resume.

• 0:38Neil deGrasse Tyson?

  You would say you were acting like a comedian?

• 0:40Chuck Nice?

  Right, yeah, that's what I'm on as well, I'm acting like a comedian, so let me just put that on the resume.

• 0:46Neil deGrasse Tyson?

  Put that in there, why not?

• 0:47Chuck Nice?

  Right, exactly, you know what I mean?

• 0:49Neil deGrasse Tyson?

  So today's topic is a fascinating one, and it's so ubiquitous. It is so ubiquitous that in fact, in the repertoire of public talks I give, one of them is entirely on this subject.

• 1:03Chuck Nice?

  Okay.

• 1:04Neil deGrasse Tyson?

  And I will visit a town, go to a theater, and 3,000 people will come and listen to me talk for two hours on this subject. And it's called Cosmic Collisions.

• 1:14Chuck Nice?

  Oh, have you been injured in an accident?

• 1:20Neil deGrasse Tyson?

  Minus the attorneys.

• 1:24Neil deGrasse Tyson?

  Yeah, most cosmic collisions, you're not injured, you are vaporized, or you die in some way.

• 1:30Chuck Nice?

  Wow.

• 1:30Neil deGrasse Tyson?

  So it's just things that-

• 1:32Chuck Nice?

  No need for a lawyer then.

• 1:34Neil deGrasse Tyson?

  Things that go bump in the night, in the day. So much that drives this universe is the result of things slamming into other things, that it's just astonishing. Ways you might not have even thought about it, to give you a simple one. For example, you've heard of aurora, you know, aurora borealis.

• 1:52Chuck Nice?

  Absolutely, northern lights.

• 1:54Neil deGrasse Tyson?

  You know what the southern lights are called?

• 1:57Chuck Nice?

  Uh, no.

• 1:57Neil deGrasse Tyson?

  Aurora Australis.

• 1:59Chuck Nice?

  Oh, okay.

• 2:00Neil deGrasse Tyson?

  Didn't know that. There you go.

• 2:02Chuck Nice?

  Crikey.

• 2:03Neil deGrasse Tyson?

  Yeah, it's it's your it's your northern hemisphere bias for you to only think of northern lights. And not think of southern lights, right? So these are collisions between charged particles from the sun. And what we call the solar wind and our atmosphere, our upper atmosphere. These particles slam into atmospheric molecules and it kicks them up to higher energy levels. And generally, atoms and molecules don't like staying at higher energy level if they can help it. And so then they then they de excite. And to de excite, in many cases.

• 2:45Chuck Nice?

  They get married.

• 2:45Neil deGrasse Tyson?

  In the cases.

• 2:48Chuck Nice?

  My life is way too exciting.

• 2:50Neil deGrasse Tyson?

  So.

• 2:51Chuck Nice?

  I need to calm this down.

• 2:54Neil deGrasse Tyson?

  So they so they'll de excite. And in many of the cases, the de excitation gives off visible light. And it's the visible light is is oxygen, it's nitrogen, it's uh, sometimes it's sodium, other sort of chemical elements in our atmosphere. That's what gives you the different colors. And because.

• 3:16Chuck Nice?

  Like fireworks.

• 3:17Neil deGrasse Tyson?

  Like and and and because the the solar wind comes in sort of waves, if I call it that, it blows in.

• 3:25Chuck Nice?

  From across the solar system.

• 3:27Neil deGrasse Tyson?

  So you so the the the Aurora can change shape like instantly, right? It's it's an active, dynamic phenomenon. And so that's just one example of cosmic collisions. And so I'm leading off with that. I don't know if anyone's gonna ask that. But apparently you got like a whole boatload of questions on this very subject. So let's see what you've got.

• 3:49Chuck Nice?

  You're absolutely right. It is a boat boat. Look at this. Every time I do this and I.

• 3:54Neil deGrasse Tyson?

  You're scrolling the screen?

• 3:56Chuck Nice?

  I'm scrolling like, yeah, yeah, look at that, look at that.

• 3:58Neil deGrasse Tyson?

  Okay.

• 3:59Chuck Nice?

  Look at that. It's it's unbelievable.

• 4:02Neil deGrasse Tyson?

  All right.

• 4:02Chuck Nice?

  The number of questions we have.

• 4:04Neil deGrasse Tyson?

  And because I give an entire talk on this, I am the local expertise on the topic. So normally, if it's a new topic, we bring in somebody to help us out on the on the cosmic queries.

• 4:15Chuck Nice?

  No need for this.

• 4:16Neil deGrasse Tyson?

  No, I'm good for this. Yeah.

• 4:17Chuck Nice?

  Yeah, oh, cool.

• 4:18Neil deGrasse Tyson?

  And if I don't know, I'll say, I don't know.

• 4:21Chuck Nice?

  All right.

• 4:21Neil deGrasse Tyson?

  But you never believed me.

• 4:23Chuck Nice?

  I was gonna say, okay, I mean, that's just not gonna happen.

• 4:27Neil deGrasse Tyson?

  All right.

• 4:28Chuck Nice?

  Actually, that's not true. There are times when you're like, okay, well, we don't know. But that's not gonna stop you from talking to the subject in some way.

• 4:36Neil deGrasse Tyson?

  That's true, because we might know something. Plus, there are two kinds of I don't knows. There's I, Neil deGrasse Tyson, don't know, because I haven't learned it. And we don't know, as is it is unknown to all humans on Earth. And part of what it is, when you get your PhD in a subject, is you learn thoroughly what we know and what we don't know. So you know where the frontier is, so you can go there and advance human understanding of the universe. Or whatever is the subject of your expertise.

• 5:06Chuck Nice?

  Irrespective of the question, the answer will never be from either you nor any of your colleagues who hold that PhD. The answer will never be, mm.

• 5:23Neil deGrasse Tyson?

  As an educator, I want you to leave still having learned something. All right?

• 5:27Chuck Nice?

  Right.

• 5:27Neil deGrasse Tyson?

  So, but all right, look, we can test it. I was like, oh.

• 5:35Neil deGrasse Tyson?

  Yeah, I'm more literate than that. Yeah.

• 5:38Chuck Nice?

  By the way, how cool would that be?

• 5:44Chuck Nice?

  Or, you know what else would be cool?

• 5:46Neil deGrasse Tyson?

  What?

• 5:48Chuck Nice?

  When you give an answer and at the end of it, you go, doy.

• 5:53Neil deGrasse Tyson?

  No.

• 5:56Chuck Nice?

  I know.

• 5:56Neil deGrasse Tyson?

  All right, give it to me.

• 5:57Chuck Nice?

  All right, here we go, here we go.

• 6:00Chuck Nice?

  This is Dade Bloomfield, and he says.

• 6:02Neil deGrasse Tyson?

  From? Do we know where they're from? I like when they tell us where they're from, no?

• 6:05Chuck Nice?

  Dade does not.

• 6:06Neil deGrasse Tyson?

  Okay, we gotta solicit that next time. Okay, so go on.

• 6:09Chuck Nice?

  So Dade says, hey, Dr. Tyson, Lord Nice, I'm Dade from Milwaukee. Sorry, there it is, Neil.

• 6:15Neil deGrasse Tyson?

  You got it. Milwaukee in the house.

• 6:17Chuck Nice?

  Inside the body of the question. How likely is it?

• 6:21Neil deGrasse Tyson?

  That just means you didn't read the questions in advance.

• 6:25Chuck Nice?

  I've got time to read these questions. You know how long some of these questions are?

• 6:32Neil deGrasse Tyson?

  Okay, Dave, who secretly two sentences later is from Milwaukee.

• 6:36Chuck Nice?

  There you go, that Dade, as in Dade County. Okay, that's so funny because I'm so busted. He says, how likely is it that if an asteroid were to hit the Earth, that we would actually notice it in time enough to react? If we noticed it today, how long do you think it would take us to come up with an executable plan?

• 6:59Neil deGrasse Tyson?

  Yes, I assume he means that if we know that tomorrow an asteroid is going to hit, what can we do in the next 24 hours? Okay, so of course it depends on the size of the asteroid, right? So 65 million years ago, when an asteroid the size of Everest struck the Yucatan Peninsula, what is today the Yucatan Peninsula, left a, you know, 100 mile diameter crater, on that order of size. It doesn't, you just kiss your ass goodbye. 70% of the world's species went extinct, okay? Including all the big tooth dinosaurs. So there's certain size asteroids where you just sit on the beach and just watch it happen.

• 7:42Neil deGrasse Tyson?

  And because there's really nothing we know how to do about it, right? So that's just that, so it's not that in principle, nothing can be done. Right now, you have people fighting over whether Earth is flat or whether they should take a vaccine. And you think we're going to coordinate in order to deflect an asteroid? I don't have that much confidence in civilization, sadly. So, but if it's smaller, let's say something that might take out a city, right?

• 8:09Chuck Nice?

  Okay, that's, yeah, so manageable.

• 8:11Neil deGrasse Tyson?

  That's manageable, totally manageable. Yeah, so, so what you do is you find out where it's going to hit. Usually there's uncertainty in the calculations of where it's going to hit. So we have what's called an error circle. But if it's something coming in at an angle, it becomes an error ellipse, an uncertainty ellipse. So usually, in other words, you know better where it's going to land left to right than you will front to back because it's headed in that direction, right? So, so the, the error ellipse is this elongated circle.

• 8:44Neil deGrasse Tyson?

  In the direction of the path of the asteroid itself. So you find out what that is and then evacuate it. Okay, that's not all that hard. I mean, think about what happens. I live in Manhattan and think about it. Every 24 hour period, millions of people enter and exit that island. Very poorly.

• 9:07Neil deGrasse Tyson?

  In their workday, okay, through a system of bridges and tunnels and boats even. So, so that's New York millions move. Okay, so it seems to me if we have some idea of the region where we'll hit, we could notify local authorities and they can clear out that zone, allowing the thing to fall so no one will actually get hit. Now, if you happen to be nearby, it's going to make it. It's going to explode on impact, make a crater. But that explosion will scatter debris into the area and it'll rain down

• 9:42Neil deGrasse Tyson?

  asteroid particles and earth particles that have been kicked up. So, but that's less deadly than being where it actually hits and explodes. And by the way, it will explode. And you say, well, how could it? How is it going to explode if it doesn't have any, any, any bombs? So here's how that works. Okay, very subtle point. It's a high speed impact, which has a very specific meaning. It's not just that it's going fast. Okay. All right. So here's an object moving through space. And you ask, well, how fast is it going? How fast is it? So you get at its speed. It'll hit us at a minimum of 25,000 miles an hour. Okay, that's about seven miles per second as a minimum. All right, but that's if it just sort of fell to earth.

• 10:26Neil deGrasse Tyson?

  If it has motion of its own, combined with motion from earth, then what you really care about is the closing speed. And then that could be upwards of 40,000 miles an hour. Okay, nearly double that. Okay, so you have to just sort of watch for those numbers. So, so here we go. So here's it coming in at very high speeds. Now you can calculate what we call the kinetic energy. You probably heard the term. It's a very specific measurement you make. You ask, how much mass is there? And how fast is it going? That's all the only two things you need. That's all you need. That's all you need. And so kinetic energy is Two ingredient cake. Is one half times the mass of the object times its velocity squared. Okay. Okay.

• 11:09Neil deGrasse Tyson?

  But the mass times the velocity squared. Oh, by the way, it's not an accident that the famous, what's Einstein's most famous equation? E equals mc squared. Notice there's a mass and c is the speed of light squared. Constant, right. But notice it's a mass and a velocity squared. It's an energy. So mass and a velocity squares are energy, no matter how you slice them. Okay? So one way to write down a value of energy is the mass times the velocity of that object squared. That's all. That's all I'm talking about. It's not an accident. Okay. That equals mc squared has that same structure to it. So kinetic energy is one half mv squared. All right. Write down that number. Okay? Write it down. Now, ask yourself, what's holding the thing together?

• 11:56Neil deGrasse Tyson?

  All right. Right. So look at, go down to the molecules and they're molecules connected to each other inside this solid object. And you can ask, with what energy are these molecules hanging on to each other? Okay. So imagine you and I standing next to each other. We just lock elbows. Okay? So we're all just molecules locking elbows. What will it take for two people to pull us apart? That's a certain energy. All right. That will either release your grip. Or rip your arm off. Or rip your arm off. Right. Both of them. You can calculate what that's energy. You can either release the molecule or bust the molecule open. All right. Right. Do that for all molecules in the object.

• 12:39Neil deGrasse Tyson?

  That's a total energy. It's called a binding energy of the object. Okay. Okay. So now I have a kinetic energy of its motion and a binding energy of the physical object. And you ask yourself, which of these is larger?

• 12:54Neil deGrasse Tyson?

  If the kinetic energy is larger than the binding energy, we'll call it a high-speed collision.

• 13:03Neil deGrasse Tyson?

  And here's what happens. This object is coming in, it slams into Earth with very high kinetic energy. Well, velocity is one of the terms in the kinetic energy equation. After it hits Earth, how fast is it moving?

• 13:16Chuck Nice?

  Oh, minus whatever.

• 13:18Neil deGrasse Tyson?

  It, how fast it.

• 13:20Chuck Nice?

  Oh, as it hits Earth, it's moving at a velocity. Oh, it already hit Earth.

• 13:24Neil deGrasse Tyson?

  It hit Earth. How fast is it moving?

• 13:25Chuck Nice?

  It's, it's just stopped.

• 13:27Neil deGrasse Tyson?

  Give me a velocity.

• 13:28Chuck Nice?

  Right, yeah. Oh, minus the.

• 13:31Neil deGrasse Tyson?

  No, no, didn't mind, I just, I'm asking a simple question.

• 13:34Chuck Nice?

  Oh, how fast is it moving? The velocity.

• 13:36Neil deGrasse Tyson?

  What is the velocity after it has hit the Earth?

• 13:38Chuck Nice?

  Oh, I don't know.

• 13:39Neil deGrasse Tyson?

  Yes, you do. It hit Earth.

• 13:42Chuck Nice?

  Oh, zero.

• 13:43Neil deGrasse Tyson?

  Thank you.

• 13:46Neil deGrasse Tyson?

  Zero.

• 13:47Chuck Nice?

  It's zero.

• 13:48Neil deGrasse Tyson?

  Okay, so then I ask you, where did all the kinetic energy go? No such thing as a free lunch in this universe. So, all that kinetic energy on impact with the Earth, it did several things. One, it makes a crater. It's, it's flies things up into space, but it also goes back into the object itself, completely destabilizing everything that's binding it together. Because it's more energy that's holding it together. And so the instant that happens, the thing can't stay together, and so it explodes. Period. That's how you get the explosion. That's why you get the explosion.

• 14:33Neil deGrasse Tyson?

  In fact, that's why every crater you have ever seen, on the moon is a good example, but look, anywhere in the solar system is a perfect circle.

• 14:42Chuck Nice?

  Right.

• 14:43Neil deGrasse Tyson?

  Even if these suckers come in at an angle, you'd think, oh, it'll make an oval crater. Yes, the uncertainty ellipse is an ellipse, but once it hits, it explodes. And the explosion is what we say is isotropic. It's, it's, the force is the same in every direction. It makes a perfectly circular crater, and usually, this, the, the object can't be found. It'll vaporize ninety something percent of the object. If you're gonna look for a big rock. That's there, you're not gonna find it.

• 15:13Chuck Nice?

  Wow.

• 15:14Neil deGrasse Tyson?

  In fact, they did. You know that big, Arizona is known for its holes in the ground?

• 15:18Chuck Nice?

  Okay, yeah.

• 15:19Neil deGrasse Tyson?

  So one of them is a meteor crater, we call it.

• 15:21Chuck Nice?

  You mean actual celestial caused holes in the, I thought you meant dive bars. I was gonna say, yeah. You're absolutely right.

• 15:30Neil deGrasse Tyson?

  No, there's holes in the wall, not hole in the ground.

• 15:32Chuck Nice?

  Oh, that's right, they are.

• 15:33Neil deGrasse Tyson?

  Yeah, yeah, that's right. So, so with that, when people said, you know, if this is, if this is left by a meteor, there ought to be a big meteor down in the middle. So they started excavating. They couldn't find anything. It's before we understood this whole concept of a high-speed impact, a high-velocity impact, where you basically vaporize the object in an explosion.

• 15:54Chuck Nice?

  It's a cosmic pillow fight where the pillow explodes and there's all the feathers.

• 16:02Chuck Nice?

  And we're still frolicking.

• 16:04Neil deGrasse Tyson?

  Well, that's an important analogy because a high-speed collision has not as much to do with the speed as it does what is the thing made of, right? So what's holding your pillow together? It's some stitching around the edge.

• 16:18Chuck Nice?

  Exactly.

• 16:18Neil deGrasse Tyson?

  If I slam it hard with more energy than that stitching, and it hits you upside the head, the stitching will break and the pillow will break open. Because in that moment, the pillow engaged in a high-speed collision.

• 16:33Chuck Nice?

  Yeah. Same thing happens with a sock full of oranges. Don't ask me how I know.

• 16:43Neil deGrasse Tyson?

  Yeah, I'm not coming over for your next sleepover.

• 16:49Neil deGrasse Tyson?

  Alright. So yeah, that's a long answer to that very, that very good question.

• 16:53Chuck Nice?

  Ah, that was cool, man.

• 16:54Neil deGrasse Tyson?

  You can evacuate, you can evacuate in 24 hours. That's why we have roads, right? And why everybody has cars. So, plus you can evacuate in every direction, okay? In most places, unless you're like in the Florida Keys or something, now you gotta go just that one direction. By the way, if it falls in the ocean, then you gotta watch out for the tsunami.

• 17:13Chuck Nice?

  Right.

• 17:13Neil deGrasse Tyson?

  Yeah, it is something to keep in mind. But most of the earth is ocean, right? And, yes, and so you just leave away from the coastline. And most of that which is land is not inhabited. So chances are, it's not gonna hit a city even if it had the power to destroy one.

• 17:31Chuck Nice?

  Oh, that's now I can sleep. Okay.

• 17:33Neil deGrasse Tyson?

  Yeah, yeah, there you go.

• 17:34Chuck Nice?

  That's not bad.

• 17:34Neil deGrasse Tyson?

  All right. Give me another one.

• 17:36Chuck Nice?

  Okay, this is Teresa Anoski. She says, how can there be a collision, cosmic or otherwise, without a lawyer being involved?

• 17:42Neil deGrasse Tyson?

  Oh, so this is a new dimension for lawyer ads, right? Right?

• 17:46Chuck Nice?

  Exactly. Was your house destroyed by a meteor?

• 17:52Neil deGrasse Tyson?

  Yeah, who are you gonna sue on that one?

• 17:54Chuck Nice?

  Yeah, yeah.

• 17:54Neil deGrasse Tyson?

  Yeah, yeah, yeah. So just an interesting point there. The, uh, one of the brightest, most devastating recent, call it recent now nine years ago, was in Cheyabinsk, Russia. There was an air blast of an asteroid 17 meters across. Some of the best footage we have of that coming in are from forward-facing dash cam footage of cars. And so here's an interesting point. And that's, you know, Europe and, uh, and parts of Asia have these to obtain video of a collision that you might be in,

• 18:37Neil deGrasse Tyson?

  which reduces the need for lawyers. Okay, often a lawyer is arguing whether something did or didn't happen, or who was at fault, or who was more at fault than they're claiming. And all of this, if you have video, that just cuts through so much of what might otherwise happen in a courtroom. So you can imagine a day where everything, I mean, I wouldn't want this because it's an invasion of privacy, but if everything, we've had a video of everything. Well, okay, that didn't make a difference with, uh, in Los Angeles in 1991.

• 19:09Chuck Nice?

  It did not. I was about to say. I was gonna say.

• 19:12Neil deGrasse Tyson?

  Sorry.

• 19:14Chuck Nice?

  You have all the video you want.

• 19:18Neil deGrasse Tyson?

  What's that boy's name? I forgot.

• 19:20Chuck Nice?

  That was Rodney King.

• 19:21Neil deGrasse Tyson?

  Rodney King. Okay, so I take it back. Apparently, video doesn't matter in some cases. Okay, if you're getting your ass whooped by the cops, apparently, it doesn't matter. But if for everything else, it might matter.

• 19:33Chuck Nice?

  Exactly.

• 19:35Neil deGrasse Tyson?

  So, yeah, it's a testament to the fact that human sensory systems are rife with error.

• 19:44Neil deGrasse Tyson?

  Not only seeing what isn't there, thinking you're not seeing something that is, hearing something that's not, perceiving. So it's such rife with error that science really didn't take off until we were able to replace our senses with machines that would have a reliability that we could only dream of having with our own eyes, ears, nose, mouth, and touch. Chuck, we got to take a quick break, but when we come back, more cosmic queries on cosmic collisions on StarTalk.

• 20:22Speaker 02

  I'm Joel Cherico, and I make pottery. You can see my pottery on my website, cosmicmugs.com. Cosmic Mugs, art that lets you taste the universe every day. And I support StarTalk on Patreon. This is StarTalk with Neil deGrasse Tyson.

• 20:43Neil deGrasse Tyson?

  We're back. StarTalk, Cosmic Queries. Cosmic collisions is the subject. One of my favorite subjects. In fact, I give a series of public talks around the country at a theater near you, and I give the host a choice of what topics they might want to hear from me. Because I have nothing really to sell you, other than the universe itself.

• 21:06Chuck Nice?

  And the ticket.

• 21:08Neil deGrasse Tyson?

  And so they see the... I don't have a product to sell you, other than, like I said, the universe.

• 21:14Chuck Nice?

  I was joking. I know what you meant.

• 21:15Neil deGrasse Tyson?

  And so it's... One of the subjects is cosmic collisions. And every now and then they pick that. And they're usually in for a treat, because it's just a fun topic. And so many things shape the universe by slamming into other things, giving us what we think of as something that's beautiful, or spectacular.

• 21:34Neil deGrasse Tyson?

  There really just something coming upside the head or something else.

• 21:37Chuck Nice?

  And I think we also have a odd fascination with the macabre and.

• 21:41Neil deGrasse Tyson?

  Yes, we do. We do.

• 21:42Chuck Nice?

  People just want to know like, how are we gonna die?

• 21:46Neil deGrasse Tyson?

  Right, right.

• 21:47Chuck Nice?

  How's it all end? Like, it's like the same thing you watch NASCAR for. For the crash.

• 21:51Neil deGrasse Tyson?

  Oh, yeah, yeah.

• 21:52Chuck Nice?

  Not one crash. This was the worst race ever.

• 21:57Neil deGrasse Tyson?

  All right.

• 21:58Chuck Nice?

  Here we go. This is Deb Beach. Deb says, hey, Dr. Tyson, a recent article from the New York Times about research in 2003 astrophysics working with astrophysicists working with NASA's Orbiting Chandra X-ray Observatory. The article notes that the sound waves were coming from a giant cluster of galaxies in the constellation Perseus caused by explosions from a huge black hole 250 million light years away. They provided a sound clip that was modified so that we could hear the quote unquote "music" of the black hole. My question is, how musical noisy is our galaxy?

• 22:36Chuck Nice?

  And what other phenomena creates sounds in space?

• 22:44Neil deGrasse Tyson?

  So, here's the thing. Here's the thing. I'm I'm not a fan of turning astrophysical data into sound. I get it, and it has some value. I'm just not a fan because of all of the off-ramps that that gives a person into thinking the wrong thing about the universe. Okay?

• 23:09Chuck Nice?

  Okay.

• 23:10Neil deGrasse Tyson?

  So let me just start it out by saying, anything, any energy that creates a change of pressure through a medium is creating sound.

• 23:21Chuck Nice?

  That's how your eardrum works.

• 23:22Neil deGrasse Tyson?

  That's how your eardrum works, okay? There's air, is pressure in the air, puts pressure on the eardrum. It gets converted to electrical, chemical signals that your brain then interprets as sound. Okay? Anything. So, so, most things.

• 23:38Neil deGrasse Tyson?

  Actually make sounds, okay? If you could, if you could hold a microphone up to the sun, it is gurgling and there are like pressure waves inside the sun. Oh, oh my gosh, I mean, gurgling, the sun is actually boiling. All right, it's a very hot, it's hot in the middle, less hot at the surface. And anytime you have a heat gradient, if that gradient is strong enough, it will, gradient is a fast change in what it is. Then you'll have boiling such as what would happen on your stove. So, point is, um, what they did was they found places in the universe where the medium, the interstellar, intergalactic medium, depending on which research results they're looking at, that there are these pressure waves through it.

• 24:23Neil deGrasse Tyson?

  Now, but they're very low frequency, very low. Like, like. The microphone. Like basso profundo low? Like basso profundo.

• 24:39Neil deGrasse Tyson?

  You all never heard basso profundo? Just Google some YouTube videos of it. It is a, it is a, it is a hoot. It's nutty, man. It's nutty, they go, the voice is so low, you can almost look at their, their, their vocal cords vibrate, you know? Yeah. Anyhow, so it is such low frequency that in order to hear it, they had to artificially boost the frequency by forty-seven, forty-eight octaves. Well, that's nothing. Octaves. Like what you heard then. Right, so if you were there, you just wouldn't hear it. The sound would sort of wash over you, you wouldn't even know it was sound. Right. So you, you boost the frequency, now you can hear it in this narrow range.

• 25:21Neil deGrasse Tyson?

  Well, we have several orders of magnitude, twenty hertz to twenty thousand hertz, if I remember correctly. And that's a nice range, but it's small compared to the total possible ranges that are out there. Go ask your dog, okay? Yeah. Okay, all right, so.

• 25:40Chuck Nice?

  That's

• 25:41Neil deGrasse Tyson?

  You know, it's funny, Chuck, you and I grew up at a time when in our biology books, the human body was praised as some kind of pinnacle of evolution. Yet, we still use our dog to sniff out drugs, because we can't, right? A dog can hear frequencies, we can't. People say, if a tree fell in the forest and no one was there to hear it, did it make sound? Yeah, because the dogs heard it.

• 26:01Chuck Nice?

  Right. That's what your dog is hearing, every time you see him, just look up like, what? And there's nothing going on, just look.

• 26:10Neil deGrasse Tyson?

  They heard the tree fall.

• 26:11Chuck Nice?

  Yeah, he was like, another tree?

• 26:13Neil deGrasse Tyson?

  Chuck, I'm gonna, I'm gonna tweet that.

• 26:14Chuck Nice?

  Right, he was like, wait, somebody just destroyed my bathroom.

• 26:19Neil deGrasse Tyson?

  Another

• 26:20Chuck Nice?

  Beat on that tree yesterday. Another perfectly good bathroom, just destroyed.

• 26:27Neil deGrasse Tyson?

  So, anyhow, the point is that if you do that and then say, these are the sounds of the universe, it's a little misleading, because it's not what you would hear. Plus, most of the rest of this space is empty, and sound needs a medium through which to transmit. And so, not only wouldn't you hear it when it was there, it wouldn't travel to you anyway. So, that's why I'm always a little uncomfortable talking about and thinking about sounds in space.

• 26:59Chuck Nice?

  Got you.

• 27:00Neil deGrasse Tyson?

  And, by the way, there is a medical condition called synesthesia. I find a fascinating condition where you, your sensory wiring is crossed. So, I think I get it right, there's some people who hear colors, who see sounds.

• 27:19Chuck Nice?

  Okay.

• 27:20Neil deGrasse Tyson?

  Yeah, so it's fascinating, sort of cross wiring of your senses. So, so here's, so what we've also done is we've taken frequencies of light in images, and because the different frequencies, there's, you know, red, orange, yellow, green, blue, violet, those are different frequencies of light. But we see way more than that with our modern equipment. We see ultraviolet, infrared, X-rays, gamma rays. So, I've seen some people take those frequencies and attach a sound to them, and then they have that sound emanating from an image, and the combination of sounds from all the data that's in the picture.

• 27:58Neil deGrasse Tyson?

  So when I first heard that, I said, no, that's, that's wrong. You can't do that. But then I realized I was, I was speaking with Richard Dawkins, who strongly suspects that because bats are mammals, and they have basically the same brains we do, a lot of the same processing power. He thinks that bats hear in color. Because what else would they be doing with the part of their brain that sees color? Why not hand it the audio signals that they're getting from their echolocation? So if a bat can hear color,

• 28:36Neil deGrasse Tyson?

  then I thought to myself, why should I have a problem with us seeing sounds?

• 28:44Chuck Nice?

  Right.

• 28:46Neil deGrasse Tyson?

  See, so, so in that regard, I, I'm, maybe we're at the beginning of a whole new way to bring data to people. Because if you're sight impaired, for example, you'd want to hear what the picture looks like. I mean, why not?

• 28:59Chuck Nice?

  That's kind of cool.

• 29:00Neil deGrasse Tyson?

  Yeah, it'd be kind of cool. There's surely a whole future in that. If you're, if you're hearing impaired or vision impaired, you bring the data into another sense. But you want to do it sort of authentically, right? If there's a separation of frequencies, you map them into a new set of frequencies that are still separated in that new regime. So anyhow, so yeah, so that's how you get sounds in the universe. And by the way, collisions and things, they all make sounds if you're right where they are. But you wouldn't hear them if you're out in space. That's the only difference. So in that regard, Star Wars would be Silent Loopy.

• 29:35Chuck Nice?

  Right.

• 29:36Neil deGrasse Tyson?

  Just so you know.

• 29:37Chuck Nice?

  And, and there goes the box office.

• 29:40Neil deGrasse Tyson?

  Okay.

• 29:44Chuck Nice?

  God, it was, it was so great. If, if only they had some kind of sound effects with it, it would have been even so much better.

• 29:55Neil deGrasse Tyson?

  Yeah, we, we don't like watching silent explosions. I think that's what that comes down to.

• 29:59Chuck Nice?

  Ah, it's Merka, baby.

• 30:01Neil deGrasse Tyson?

  Merka. We're really good at blowing stuff up, and we're less good at knowing where the pieces go at the end, by the way. That's a whole other conversation. Chuck, you got to take a quick break. When we come back, part three of our three segment cosmic queries about cosmic collisions.

• 30:23Neil deGrasse Tyson?

  Chuck, we're back. You know, I've been giving sort of luxurious answers to those several questions we've had so far.

• 30:29Chuck Nice?

  That's funny.

• 30:30Neil deGrasse Tyson?

  No, let's do a little bit of lightning round. I'm ca- I want to show people I'm capable of that.

• 30:34Chuck Nice?

  Yeah, I'd just say we do another show, a second show.

• 30:37Neil deGrasse Tyson?

  Other cosmic query.

• 30:38Chuck Nice?

  If you didn't get your question asked, then come back.

• 30:41Neil deGrasse Tyson?

  We'll do it again, alright.

• 30:42Chuck Nice?

  We'll do it again, you'll get your question.

• 30:44Neil deGrasse Tyson?

  Alright, we'll try it. I'm still gonna try it, okay, go.

• 30:46Chuck Nice?

  Okay, we'll try it, here we go, here we go. Zachary Clair, clear, clear, clear. Okay. Zachary says, greetings, Dr. Tyson, Lord Nice. I recently read that upon a recent published work in which researchers suggest that when two progenitor galaxies collided head-on, their dark matter and stars would have sailed past each other. The dark matter would not have interacted with the stars, which would not have been able to, uh, too far apart to collide. But as the dark matter and the stars sped up, the gas in the space between the two galaxies and stars would have crashed together, compacted, and slowed down, leaving a trail

• 31:27Chuck Nice?

  of matter that formed, dun dun dun, a new galaxy. You just described galaxy sex, bro.

• 31:41Neil deGrasse Tyson?

  Wait, did his question have that, the sound effects in there too? Or did you add those?

• 31:45Chuck Nice?

  No, I add.

• 31:47Neil deGrasse Tyson?

  Did he go, ta ta ta?

• 31:48Chuck Nice?

  Yeah, no.

• 31:49Neil deGrasse Tyson?

  Everything, everything spoken there is accurate. So, here's what happens. The galaxy collision is one of the most beautiful balletic things you've ever seen.

• 32:01Chuck Nice?

  Okay.

• 32:01Neil deGrasse Tyson?

  So first of all, galaxies are mostly empty of stars.

• 32:05Chuck Nice?

  Right.

• 32:05Neil deGrasse Tyson?

  Alright, so if there were just a few bumblebees flying randomly in the continental United States, there's a greater chance that two of them would accidentally bump into each other than for two stars to collide when, when two galaxies come together in space. That's how empty, empty space is.

• 32:25Chuck Nice?

  Wow.

• 32:25Neil deGrasse Tyson?

  So, so, when the two galaxies come, they will basically pass through each other and come out the other side. Okay? The dark matter, whatever that is, we don't know what it is, the dark matter will do the same. Why? Because dark matter not only doesn't interact physically with our matter, it doesn't interact chemically, it doesn't interact with itself. So we would have to interact in order to make a dark matter planet, for example, or a dark matter star. Something has to work such that it can become compactified. Why are you a solid object, Chuck? Because your molecules are sticking, sticking to each other in some way that it turn you into Chuck.

• 33:05Neil deGrasse Tyson?

  Dark matter, as far as we know, has no ability to stick to us or to stick to itself. So the dark matter passes. But the gas clouds, oh, they're not gonna, you can't pass gas through gas.

• 33:18Chuck Nice?

  Yeah.

• 33:19Neil deGrasse Tyson?

  All right.

• 33:22Chuck Nice?

  I'm sorry.

• 33:23Neil deGrasse Tyson?

  Before I trigger a cascade of flatulence jokes from Chuck. Not that we can't pass gas. But, uh, gas clouds cannot move through other gas clouds without consequence. And it's like two hot marshmallows touching each other. They stick.

• 33:43Chuck Nice?

  Right.

• 33:44Neil deGrasse Tyson?

  You ever done that, two hot marshmallows?

• 33:45Chuck Nice?

  Absolutely.

• 33:46Neil deGrasse Tyson?

  It's like, it's like contact cement. So, so everything else passes through each other. The gas sticks together and that energy feeds the formation of new stars. And so you could, so these, these, these, these filaments of gas that are left over from these collisions, we, we can basically form an entire family of dwarf galaxies by doing this.

• 34:10Chuck Nice?

  That is pretty damn amazing.

• 34:14Neil deGrasse Tyson?

  So, yeah, so these are collisions and the problem is it takes about a quarter billion years to fully go through this collision. So we know they happened primarily only because we simulate them on the computers. And just, just so you, I want you to appreciate my people, okay? If you're gonna collide two galaxies, every inch, the galaxy moves closer to itself.

• 34:39Neil deGrasse Tyson?

  The sum of all the gravity vectors operating on every point in space changes.

• 34:46Chuck Nice?

  Right.

• 34:47Neil deGrasse Tyson?

  So if you're a star, you take three steps to the left. Everybody else took three steps to whatever they're going. And now the total gravity field is different. And so you have to recalculate what's tugging on you and in what direction. And once you go through this exercise, that's when you find this extraordinarily balletic collision. It's like two, it's like a train wreck, right? The, the structure, the beautiful structures of the galaxies get completely destroyed and distorted. And it's just beautiful. So if I wanted to see a phenomenon in the universe, I would want front row seats for a quarter billion years on the collision of galaxies.

• 35:26Chuck Nice?

  Very cool.

• 35:27Neil deGrasse Tyson?

  Oh, I left something out. So these gas clouds will make their own shards of galaxies. But the system of stars, they will pass through each other, come out the other side, but they still see one another. And then they'll slow down, stop, and then collide again. And this will continue until it settles into a new galaxy. Into a new galaxy that is completely, that has lost all of its, if there were spiral galaxies, completely lost all of its beautiful spiral structure. And it'll become one big giant blob of stars. And if they each had black holes, the black holes will find each other and merge in the middle.

• 36:06Chuck Nice?

  Okay.

• 36:07Neil deGrasse Tyson?

  Yeah.

• 36:07Chuck Nice?

  All right.

• 36:08Neil deGrasse Tyson?

  To back up when that's happening.

• 36:09Chuck Nice?

  Yeah, man.

• 36:11Neil deGrasse Tyson?

  All right, that was not a soundbite answer, so keep going.

• 36:14Chuck Nice?

  That was, that was fascinating.

• 36:15Neil deGrasse Tyson?

  All good.

• 36:16Chuck Nice?

  Fascinating. Here we go. Hello, Dr. Tyson, Lord Nice. This has been plaguing me for a couple of years now.

• 36:23Neil deGrasse Tyson?

  Who is this? Who is it?

• 36:24Chuck Nice?

  Oh, I'm sorry, yeah, James Weldon, sorry, James.

• 36:26Neil deGrasse Tyson?

  Thank you.

• 36:27Chuck Nice?

  Yeah. This has been plaguing me for a couple of years now. Is it possible the Big Bang and the Big Rip are causally connected?

• 36:38Chuck Nice?

  I heard from a science YouTuber once that the amount of energy needed to split elementary particles such as quarks is so infinitely great that the very act would mathematically create new elementary particles rather than actually splitting them.

• 36:54Neil deGrasse Tyson?

  Well, I like that. By the way, the namesake of this format, Cosmic Queries, became a book published by National Geographic a couple of years ago, and there's an entire section on how the universe will end.

• 37:08Chuck Nice?

  Ooh.

• 37:08Neil deGrasse Tyson?

  All right, and all the hypotheses are there, including the Big Rip, which would happen in 22 billion years if, in fact, the acceleration of the universe continues. So, here's what's interesting about the universe. Wherever you have a lot of energy, stuff happens.

• 37:25Chuck Nice?

  Okay.

• 37:25Neil deGrasse Tyson?

  Stuff happens. I'll give you an example, okay? Do you know what protons and neutrons are made out of?

• 37:32Chuck Nice?

  Sugar and spice and everything nice.

• 37:35Neil deGrasse Tyson?

  Yes, precisely that, Justin. They're made out of quarks, okay? Now, we've never found an isolated quark. They're always in pairs. Okay, always. Okay? All right, so now, well, why not? Why don't we just get in there and rip them apart?

• 37:50Chuck Nice?

  Right.

• 37:51Neil deGrasse Tyson?

  Well, here's what happens. As you pull them apart, they pull on each other more strongly

• 37:56Chuck Nice?

  Oh.

• 37:57Neil deGrasse Tyson?

  as the distance increases.

• 37:59Chuck Nice?

  It's like a finger puzzle.

• 38:00Neil deGrasse Tyson?

  Okay. Or, or something even... Do people have finger puzzles anymore?

• 38:06Chuck Nice?

  No.

• 38:07Neil deGrasse Tyson?

  Okay, they don't really have... But, well, just a rubber band does that.

• 38:10Chuck Nice?

  Right, that's true, yeah.

• 38:11Neil deGrasse Tyson?

  Right? As you pull on it, it's pulling on you more strongly. So, this is a force that operates the way a rubber band does. But watch what happens. If you pull on a quark with enough strength, "I finally got it! Check, check, I got it, I got it!" And then it snaps into two, the energy you put in was exactly enough for the snapping rubber band to create another quark. And now you have two pairs of quarks instead of one.

• 38:39Chuck Nice?

  Nice.

• 38:40Neil deGrasse Tyson?

  Yes, yes, it is, it is like, don't F with me.

• 38:44Chuck Nice?

  Yeah.

• 38:45Neil deGrasse Tyson?

  You see I'm happy here as a pair of quarks.

• 38:47Chuck Nice?

  Yeah. That's some loan shark stuff right there.

• 38:51Neil deGrasse Tyson?

  That's right. So I like the idea that the energy required to rip the universe, the very fabric of it, is sufficiently high that it could create multiple big bangs. I haven't researched that enough to know if there's something that would prevent it, but I'm telling you that energy is opportunistic.

• 39:10Chuck Nice?

  Right.

• 39:10Neil deGrasse Tyson?

  And so I like that possibility.

• 39:12Chuck Nice?

  Yeah, this is kind of cool. It's just like.

• 39:14Neil deGrasse Tyson?

  So it could be that our big bang was somebody else's big rip.

• 39:16Chuck Nice?

  Somebody's big rip.

• 39:18Neil deGrasse Tyson?

  Yeah, yeah, there you go.

• 39:19Chuck Nice?

  Oh, man, I don't, I don't want everything to come from a, any term, anything termed the big rip. So I don't want that to be, I don't.

• 39:30Neil deGrasse Tyson?

  I don't know what else to call it. It is, the universe is ripping. I don't know what else I'm gonna do, you know? Yeah, but if you go, if you check out the book, there's a whole section, if you want to know all the ways the world would end.

• 39:39Chuck Nice?

  All right.

• 39:40Neil deGrasse Tyson?

  Chuck, I don't, we spent so much time, Chuck, and we didn't have time.

• 39:43Chuck Nice?

  No.

• 39:44Neil deGrasse Tyson?

  All right, one more, quick, quick, quick.

• 39:45Chuck Nice?

  All right, here we go.

• 39:46Neil deGrasse Tyson?

  Go quick.

• 39:46Chuck Nice?

  Dr. Tyson Lord Nice, when we detected gravita-

• 39:48Neil deGrasse Tyson?

  Who is this?

• 39:49Chuck Nice?

  Wait, wait, who was it? Who was it? Jason Whiteer.

• 39:53Neil deGrasse Tyson?

  Okay.

• 39:53Chuck Nice?

  Jason Whiteer, or, okay. Uh, Dr. Tyson Lord Nice, when we detected gravitational waves from the collision of two black holes, what happened to their event horizon?

• 40:04Neil deGrasse Tyson?

  Oh, very cool.

• 40:07Chuck Nice?

  That's a great question.

• 40:08Neil deGrasse Tyson?

  It, it is, it is. And in fact, don't we have an explainer on this with our black hole in residence, uh, black hole expert in residence?

• 40:15Chuck Nice?

  Jan Levin.

• 40:16Neil deGrasse Tyson?

  Jan Levin.

• 40:17Chuck Nice?

  Yes.

• 40:17Neil deGrasse Tyson?

  I think we, we do talk about this.

• 40:19Chuck Nice?

  Yes, we do.

• 40:20Neil deGrasse Tyson?

  I think it was in an explainer, but I'll just tell you right now, and then we gotta call it a quits.

• 40:24Chuck Nice?

  Okay.

• 40:24Neil deGrasse Tyson?

  Um, so what happens is the two event horizons. Merge to become one larger event horizon, surrounding the total mass of the two objects together. That's what happens.

• 40:38Chuck Nice?

  Ah.

• 40:38Neil deGrasse Tyson?

  Okay, they enter each other's event horizon when this happens. And Jana gives a brilliant explanation for how that happens and why it happens. And so I recommend you do a fast search on that and you'll get there. All right, Chuck, we're gonna call it quits there.

• 40:53Chuck Nice?

  That was great, man. And guess what? We still have like 60 questions left.

• 40:58Neil deGrasse Tyson?

  Okay, okay.

• 41:00Chuck Nice?

  Which is awesome.

• 41:01Neil deGrasse Tyson?

  All right, well, we'll do this again. We totally will do this again. Cosmic Queries, second edition, the sequel. And we'll just number them up because there's no end of this. And like I said, it's one of my favorite subjects. So Chuck tweeting at Chuck Nice Comic.

• 41:14Chuck Nice?

  Thank you, sir. Yes.

• 41:15Neil deGrasse Tyson?

  I never give my social media handles on this, but maybe I'll.

• 41:18Chuck Nice?

  Because you don't need to. If I had 14 million people following me on anything. By the way, I would stop giving it like, hey, guys, stop. Take it easy. Chill out, okay? I need a second. Can I get a second? You know?

• 41:38Neil deGrasse Tyson?

  All right, I'll do this one time, okay? On Twitter, it's Neil Tyson.

• 41:41Chuck Nice?

  Right.

• 41:41Neil deGrasse Tyson?

  And on everything else, it's Neil deGrasse Tyson. On Facebook, TikTok even. And the TikTok is an official TikTok of StarTalk, by the way. We have a bunch of us making sure that works out. And I'm in all the content, but we have people, experts, TikTok, you know, people one third my age. That's a definite TikTok expert.

• 42:02Chuck Nice?

  It's cool, man. Oh, that's so funny. Yeah, I got a toddler just like, here's your problem.

• 42:11Chuck Nice?

  You're not gonna be able to get engagement if you keep doing this.

• 42:16Neil deGrasse Tyson?

  Exactly.

• 42:17Chuck Nice?

  By the way, do you know when they're gonna stop this shortage of baby formula?

• 42:28Neil deGrasse Tyson?

  All right, this has been Cosmic Queries, Cosmic Collisions Edition, the first of what will surely be many. Neil deGrasse Tyson here. Keep looking up.