Cosmic Queries – Big Bang Bonanza with Brian Keating

What happened before The Big Bang? Neil deGrasse Tyson and comic co-host Matt Kirshen answer questions about inflation theory, multiverses, the cosmic microwave background, and the possible end of the scientific method with cosmologist Brian Keating

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. And today I've got Matt Kirshen with me as my co-host. Matt, how you doing, man?

• 0:25Matt Kirshen?

  I'm good, thanks. I'm coming to you from sunny Colorado. I'm at the in-laws' house right now, so...

• 0:30Neil deGrasse Tyson?

  At the in-laws. Do we really need to know, like, you know?

• 0:34Matt Kirshen?

  I'm just letting you know this, just so that if anyone's watching the video rather than just pure audio, you know that this arrangement behind me was not my doing. This is, uh, it's already been commented by Lindsay, the producer, that I look the most like the professor out of anyone on this Zoom right now. You've all got pristine clean offices. I've got papers, reference books. I feel very educated right now.

• 0:55Neil deGrasse Tyson?

  Okay, now I gotta hold up that side of that promise. So Matt, Matt's your comedian and you host a podcast, mostly science.

• 1:04Matt Kirshen?

  Probably science, probably.

• 1:09Neil deGrasse Tyson?

  Probably science. One day I'll get, it'll be completely perfect.

• 1:13Matt Kirshen?

  So close, so close.

• 1:13Neil deGrasse Tyson?

  And I've been a guest on your program and I've enjoyed it and I'm waiting for my invitation to come back.

• 1:18Matt Kirshen?

  Well, you've got a book coming out soon, haven't you? You've got a...

• 1:21Neil deGrasse Tyson?

  A month, like not now, but yeah, in a while. Okay. If that's enough to get me back on your show, I'm delighted.

• 1:28Matt Kirshen?

  Well, I never want to ruin my, uh, I don't want to overplay my hand when it comes to getting the big guns on the show.

• 1:35Neil deGrasse Tyson?

  So we're here because we've got a topic that is at the beginning of everything, right? The subject today is the Big Bang, the cosmic microwave background, inflation, the origin of the universe, everything that started at the beginning. And I have some expertise there, but not enough to like drive an entire Cosmic Queries. So we went combing the universe.

• 2:04Neil deGrasse Tyson?

  And we found Professor Brian Keating. Brian, welcome to StarTalk.

• 2:08Speaker 02

  Thank you.

• 2:09Neil deGrasse Tyson?

  So you're a cosmologist, Chancellor's Distinguished Professor of Physics, University of California, San Diego, UCSD, and you've got a podcast of your own, which I was also a guest on. I love the title of that one, Into the Impossible. So that just sounds like fun. And where you take the guests and where you take the audience.

• 2:28Speaker 02

  Yeah.

• 2:29Neil deGrasse Tyson?

  And so we've got you here. Just let's lay some fundamentals just for the show before we go to Matt as he digs up the questions we've solicited from our Patreon members. But just, what are like the three biggest reasons why we're all convinced that the Big Bang was a real thing?

• 2:49Speaker 02

  Well, I think there's multiple pieces of evidence, but I think none stronger is the fact that we exist and we're made of matter, and that matter came from somewhere. And where it came from, I think, is best described in the least ignorant form of description as the Big Bang. It means a lot to different things, some correct things, some incorrect things, but the fact that there's sort of shrapnel left over from the most cataclysmic explosion, literally, in the history of the cosmos, the biggest explosion that ever could be envisioned. It is perhaps not surprising that cosmologists such as myself look to whatever's left over from this explosion to tell us what it was like when that explosion

• 3:34Speaker 02

  happened. And I think the problem that the layperson has is the conflation, not the inflation, we'll get to that, but the conflation of the Big Bang with the origin of time, with the origin of the universe, and they need not be synonymous. And I think that's the most interesting development in the last few years is this realization that what we call the Big Bang is really the terminus on a voyage backwards from today where our ignorance really ends, which is at this epoch when the first elements in the periodic table were formed. And that took place in a period of time much, much shorter than an episode of the Big Bang Theory TV show. So I think it's fascinating that we are all

• 4:19Speaker 02

  leftover byproducts. You know, your friend and mentor Carl Sagan, we talked about when you were on the Into the Impossible podcast, he used to say, "We're all star stuff," but most of us is hydrogen, and that hydrogen came from the Big Bang. So we're actually... Big Bang stuff more than we are star stuff.

• 4:36Neil deGrasse Tyson?

  I like that better. I want to be Big Bang stuff.

• 4:41Speaker 02

  I mean, that does sound a bit like a ska band, but.

• 4:44Neil deGrasse Tyson?

  Oh, yeah, yeah, very, very good.

• 4:46Speaker 02

  There is a, there is a sentence you said, a phrase you said in the middle of that that really struck me where you said the Big Bang is where our ignorance ends. Because I think, you know, I would have, certainly younger me and probably me just now would have said it's where our, our knowledge ends, but.

• 5:00Neil deGrasse Tyson?

  Oh, no, no, you, he's coming the other way on the time vector there.

• 5:03Speaker 02

  Yeah.

• 5:04Neil deGrasse Tyson?

  Once you have the Big Bang, everything was before that, we're like ignorant of and we're poking in the dark. And now our knowledge begins going forward. Did I get you right there?

• 5:13Speaker 02

  Yeah, that's absolutely right.

• 5:15Neil deGrasse Tyson?

  Okay, yeah. So, so Matt, you were thinking backwards on that one, in spite of all the books that are in your space there.

• 5:20Speaker 02

  I know, if only any of them were physics related, or I had read any of them.

• 5:27Speaker 02

  Well, there's a lovely Japanese word, which, which I love to bring out on my friends, except if they're Japanese, many of my collaborators are. It's called, I think it's called sanduku, not Sudoku, but sanduku. It's the art of buying books without the intention of reading them. And you'll find, you'll find.

• 5:43Neil deGrasse Tyson?

  They have a word for that?

• 5:44Speaker 02

  Neil's books. Yeah, they have a word for everything.

• 5:46Neil deGrasse Tyson?

  They got a word for that?

• 5:47Speaker 02

  Yiddish, you know, they're like, it's a word for everything, Neil.

• 5:50Neil deGrasse Tyson?

  Oh, my gosh, we need that word.

• 5:55Neil deGrasse Tyson?

  So tell me also about inflation, what everyone's heard so much about. What was the need for it? Because it feels like an add-on to the Big Bang. I mean, who ordered that, right?

• 6:04Speaker 02

  Exactly.

• 6:05Neil deGrasse Tyson?

  The Big Bang was, was kind of doing okay without it. And now we need inflation and now we're fine. Okay.

• 6:11Speaker 02

  That's right. Yeah, I always say, you know, our job as cosmologists, when one of my students graduates, I tell, I tell him or her, I say, congratulations. You've now earned your ticket to an even harder problem, you know, because our job is to find the flaws in the currently existing paradigms of, of the universe. So what happened originally, we go back way back, we go back to, to this guy. You know, I'm sorry to infringe upon Matt's territory. I don't know, Matt, if you're a prop comic, but I'm a prop cosmic. I like all my cosmology puppets. I got one of Neil in my office. I broke that out. Last time, but here's Galileo. We'll break them out as necessary.

• 6:46Neil deGrasse Tyson?

  So Brian is holding up finger puppets, sock puppets of various people. Okay. And he just held up Albert Einstein. Okay.

• 6:54Speaker 02

  Yeah. So Einstein and many of his contemporaries for thousands of years prior to him, believed the universe was eternal, static, perhaps cyclic if you go back way far before. In the Egyptian cosmology of the thousands of BCE years, people believed in either cyclic or static, some version of an eternally existing universe. And it wasn't until the late 1920s when the notion that the universe was dynamic and not static came into play, based on evidence collected by Vesto Slyfer, Henrietta Levitt, and of course Edwin Hubble. And these scientists ushered in this notion that was allied with a theoretical

• 7:36Speaker 02

  conception by a Belgian priest named Lemaître, that the universe could have been and should have been much smaller in the past if today it's much, much larger and tomorrow it'll be larger yet. So the notion that the universe began with the Big Bang really got ushered in in that epoch. But, and it's less than 100 years old. It's pretty fascinating to think about that. And it's had its own incarnations, but it was dissolved to solve a problem in the pre-existing cosmogony, the origin of the universe not existing, that it being static eternal. Well, that was inconsistent with evidence. Big Bang comes along, boom, that supplants it with evidence and data.

• 8:10Neil deGrasse Tyson?

  I see what you did there. You said boom. I see what you did there.

• 8:13Speaker 02

  Boom in there. You gotta put a bang in there every so often, per my contract

• 8:19Speaker 02

  with Big Bang Productions. And then, as often happens, the ticket that I said is to solving a problem is a new problem. And so people realize the, I'm going to drop another word on you that Neil will know, but our British friend might not, lacuna. You know, we have a gap in our, in our, in our understanding, based on the data, based on the observations, that there was something incommensurate with the Big Bang theory that couldn't be explained. Namely, how the universe got its spots. Behind me, I have a beach ball if you're watching. And if you're listening, it's an inflatable beach ball produced by the WMAP team, Neil's friend, David Spiegel, and others have produced a beach ball representation of the fluctuations in the cosmic microwave background, which is what I study. I assume we'll get into that.

• 9:01Speaker 02

  And other features of the universe became incompatible with a universe that was that was purely emerging from a singularity or from a very compact dense state. And to explain the peculiarities that were observed in the data in the 1970s, as Neil said, we required some kind of explanation. That explanation was conceived by Alan Guth and Paul Steinhardt and Andre Linde and many others, Stephen Hawking, to have different features of what we now call inflation. But the difference is that there is sort of, there is evidence for inflation, but I would say it's more circumstantial. So what inflation explains is why the universe is so large, so flat, and possessing tiny

• 9:46Speaker 02

  fluctuations, and also having other properties that we can observe in the data about the various amounts of particles, energy, forces, and fields. And so it's exciting, but it's not proven.

• 9:58Neil deGrasse Tyson?

  Right now, inflation is about 7%. So what percent inflation was the universe?

• 10:04Matt Kirshen?

  Can I take it further back? Because I'm confused here. So just to be clear, there is a difference between inflation and expansion, because expansion has been...

• 10:14Speaker 02

  Yes.

• 10:15Matt Kirshen?

  Expansion is what we, I've known, you know, learning from like school physics, is the universe is expanding. We know that from like redshift, Doppler effect, and you reverse it back, and that's how you calculate when the Big Bang happened.

• 10:27Speaker 02

  Correct.

• 10:28Matt Kirshen?

  What's inflation and how is that different?

• 10:30Speaker 02

  You could think of inflation, if you think of the Big Bang, as an explosion. It's not an explosion in the conventional sense, but it could be helpful to think about it as an explosion happening everywhere at a single moment in time, if indeed that did launch the origin of time, we can talk about that. But the spark that ignited that explosion, if you will, relies in the inflation paradigm on a quantum field, a new object, a new entity in the inventory of the energy budget of the universe. And that energy is provided by a quantum field called the inflaton or inflaton. And that drove this exponential expansion of the universe that happened a trillionth

• 11:12Speaker 02

  of a trillionth of a trillionth of a second after the Big Bang, if the Big Bang was indeed the origin and a singularity in the classical conception of that term. And that lasted for less than a trillionth of a trillionth of a second. And in that time, the universe inflated from a grapefruit size to thirty orders of magnitude larger than a grapefruit size. And that happened at a rate, if you calculate how fast that would occur, it's far in excess of the speed of light. And so it's the ultimate energy injection into the universe. It has many properties in common with what we call dark energy and the cosmic acceleration that we observe today that was awarded to, a Nobel Prize was awarded to three physicists in 2011.

• 11:57Speaker 02

  Dark energy cosmic acceleration. That new field, which we just call dark energy, has many properties in common with the inflation occurrence. But the inflation would have occurred thirteen billion years, almost fourteen billion years earlier. So inflation is the spark that gives the impetus that causes the universe to expand to the vast size that it is today in an exponentially small amount of time. And that explains why the universe has the particular pattern of microwave background fluctuations that my colleagues and I study.

• 12:29Neil deGrasse Tyson?

  So I want to go to our questions real quick, but just frankly, Brian, if I were hearing all that for the first time, it sounds like you just made it all up just now. It sounds like, God, can't explain that. How about inflation? Yeah, okay, how about, yeah, that's a ticket. Yeah, how about? Let's go.

• 12:49Speaker 02

  Yeah. You know those books, Neil, that say, everything I needed to learn, I learned about in kindergarten? Well, everything you needed to learn about inflation, you can learn in advanced quantum mechanics.

• 12:59Neil deGrasse Tyson?

  Okay, all right, well, there you go. So Matt, give me what you have for us, Matt.

• 13:02Matt Kirshen?

  So there's a bunch of questions immediately right on this subject. So Chris Love asks, regarding the cosmic microwave background, whenever I see an image that represents it, there are hot and cold spots all over it. I'm curious what the mechanism might be that causes those hot and cold spots. Is it the distribution of normal matter, dark matter, the expansion of spacetime, or something else? Thank you for the knowledge and keep looking up.

• 13:22Neil deGrasse Tyson?

  And also, you know, because all those maps are color-coded to represent temperature, we're left with the impression that you touch one spot, it feels hot. You touch one other spot, it feels cold. So, but that's not, no, this, that's just to help the viewer.

• 13:38Speaker 02

  Yeah. In a sense, yeah. They really are hotter or colder, but let me explain first.

• 13:43Neil deGrasse Tyson?

  Yeah, but by how much?

• 13:45Speaker 02

  Oh, well, a very, very, you know, frosty, uh, ten, one millionth of a degree Kelvin. Yes, exactly. You're not, you're not gonna pick that up on your, on your Edmund Scientific Thermometer.

• 13:55Neil deGrasse Tyson?

  Right, right. So the hot sections are...

• 13:58Speaker 02

  About a hundred microkelvin hotter than the average CMB temperature, which is 2.7 Kelvin.

• 14:03Neil deGrasse Tyson?

  Got it, got it.

• 14:03Matt Kirshen?

  2.7 Kelvin, which is...

• 14:05Speaker 02

  Yes.

• 14:06Matt Kirshen?

  Pretty, pretty chilly.

• 14:07Speaker 02

  Which is minus 400, yeah, it's a frosty day in Denver where you're at, Matt. It'll be 454 degrees below zero Fahrenheit.

• 14:13Neil deGrasse Tyson?

  I just want to make it clear that we say there are hot and cold spots, but the, the, the range in that temperature is smaller than any two places in the room you're in.

• 14:23Speaker 02

  That's right. Right. Well, Neil, well Neil, you know better than anybody, you know, what cosmologists will call a crisis, the fact that a boson has a one billionth of a percent more mass than a, than it was expected to. That's a crisis!

• 14:35Neil deGrasse Tyson?

  Yeah, yeah, yeah. I'm not jumping out any windows on that one. Right.

• 14:39Speaker 02

  That's right. Yeah. So, so to, uh, to explain these fluctuations in the cosmic microwave background, let's explain what the CMB is. The CMB is the Cosmic Microwave Background. It's an all pervasive field of photons coming to us as if we're inside of an enormous oven. And that oven, thank God for us, is only at a temperature of 2.7 degrees above absolute zero, or 450 or so degrees below zero Fahrenheit. And that was discovered in 1965 in, of all places, New Jersey. And I'm a New Yorker, Neil, so I can make fun of New Jersey. I have a ticket, I have a license to do that. So it was discovered in Holmdale, New Jersey, by Penzias and Wilson. They couldn't get rid of it, no matter where they looked, when they looked, how they looked. This background radiation comes to us in all directions. Uh,

• 15:24Speaker 02

  and they thought it was perfectly uniform, but over the decades, cosmologists realized it has major amounts of, a very difficult word to pronounce for the first time, but anisotropy. So anisotropy means not isotropic. Isotropic means it looks the same everywhere you look. And so these are notions that have to be explained. Why is the universe very, very close to perfectly uniform, but it's not perfectly uniform? We've known since the time of Isaac Newton, the finger puppet somewhere around here. Isaac Newton said, if the universe were perfectly static and isotropic everywhere you looked, then we would never form. There'd be nothing to break the symmetry and say, oh, a planet should form here, a star should form there, under even the Newton.

• 16:07Neil deGrasse Tyson?

  Matter would just be equally spread everywhere.

• 16:09Speaker 02

  Yeah. It would never, it would never condense and collapse and form, uh, form bound gravitational structures. So we've known that the universe couldn't be perfectly uniform in that everywhere you looked in the universe, you saw the exact same temperature.

• 16:21Neil deGrasse Tyson?

  But the question is, what's causing it?

• 16:24Speaker 02

  Yeah. So what's causing it was the reason that inflation needed to be explained. So in the inflationary paradigm, the explanation comes from the fact that the thing that blew up the universe by 30 orders of magnitude from an initial cosmic primeval seed was a fluctuation in a quantum field, what's called a scalar field. And that field, I called it before, the inflaton. This quantum field, like all quantum fields, like the Higgs boson, like the photon field, like any field that you so choose in, uh, in physics, has unavoidable, irreducible quantum fluctuations. A quantum fluctuation is an expression of the Heisenberg uncertainty principle, that

• 17:06Speaker 02

  you can't know exactly all the information about a quantum field or quantum particle, a photon, an electron, a crouton, my favorite particle. You can't know everything about them with infinite precision. If you do, you have complete uncertainty in other aspects of its, of its property. So one thing we know is that at this extremely brief epoch of time in inflation, there would have been large fluctuations in the amount of energy in the universe. And Einstein says that all forms of energy are equivalent to sort of a mass fluctuation via the most famous equation in all of science, equals mc squared. So the theory is this, the inflaton is a quantum field. It, like all quantum fields, has fluctuations.

• 17:49Speaker 02

  Those fluctuations can be equated to sort of mass inhomogeneities. And those mass inhomogeneities, then, according to Einstein's general theory of relativity, equate to the curvature of spacetime, which the question are asked about. So if you look at the fundamental logic of progression, inflation explains the CMB fluctuations by the fact that this quantum field had these irreducible perturbations, these fluctuations, thanks to Heisenberg. Now, all this presupposes that inflation exists, which we don't know about. And what my team of scientists in the Simons Observatory is attempting to do is build an experiment, an instrument, to collect data to provide evidence for those quantum fluctuations. And we can get into how we do that.

• 18:32Speaker 02

  But the base answer to that question, that was very astutely posed by the audience, is that they do represent actual overdensities in temperature and in matter in the early universe that were caused by primordial seeds themselves caused by fluctuations in this quantum field. I know it sounds complicated, but I mean, your audience is pretty brilliant, so I don't want to underestimate it.

• 18:54Neil deGrasse Tyson?

  As Lady Gaga says, "Born that way." That's what you... Okay.

• 18:59Speaker 02

  All right, we're going there.

• 19:01Neil deGrasse Tyson?

  We'll take a quick break. When we come back, we'll get right back into questions with our guest, Brian Keating, who is a cosmologist, who's taking us back to the beginning of things, the beginning of time, space, energy, and all that. And I got Matt Kirshen helping me out here when we return.

• 19:28Speaker 03

  Hi, I'm Chris Cohen from Hallworth, New Jersey, and I support StarTalk on Patreon. Please enjoy this episode of StarTalk Radio with your and my favorite personal astrophysicist, Neil deGrasse Tyson.

• 19:52Neil deGrasse Tyson?

  We're back. Startalk Cosmic Queries, Cosmology Big Bang Edition with cosmologist Brian Keating, who hosts the podcast Into the Impossible, which, Brian, that comes from a quote from Arthur C. Clarke? Is that right?

• 20:07Speaker 02

  Yeah, that's right. Yeah. So when you were on my podcast, I'll have you back on hopefully this fall, and it's a famous quote, Arthur C. Clarke. So I direct, co-direct the Arthur C. Clarke Center for Human Imagination at UC San Diego.

• 20:18Neil deGrasse Tyson?

  Excuse me?

• 20:19Speaker 02

  Yes, that's right.

• 20:20Neil deGrasse Tyson?

  You're happening to do.

• 20:21Speaker 02

  In my spare time.

• 20:25Speaker 02

  And Sir Arthur had many aphorisms, many cosmic quips. One of them that you like is, "For every expert, there's an equal and opposite expert." He also said, "For every, any advanced technology is indistinguishable from magic." And then he said, "The only way to determine the limits of the possible is to go beyond them into the impossible." So that's the origin of our podcast.

• 20:47Neil deGrasse Tyson?

  Cool. Into the Impossible. One other thing before we pick up our next question with Matt. We're in, this year, we're in the 2020s, and this is like the centennial decade of all kinds of wild, freaky discoveries made in the 1920s, Brian. And, and I, when I think back on that, to me, the 1920s must have been the, the greatest watershed decade in physics of any decade there ever has been, or perhaps will be, from the expanding universe to Einstein, you know, and they were trying to figure out Einstein. Does any special memory you have?

• 21:29Speaker 02

  Yeah, well, I'm not quite that old, Neil, but.

• 21:31Neil deGrasse Tyson?

  Oh, okay, okay.

• 21:32Speaker 02

  But it's true, yeah.

• 21:33Neil deGrasse Tyson?

  You've held up well. No, no.

• 21:35Speaker 02

  The discovery of antimatter, the prediction of antimatter, quantum field theory, all these wonderful things. Yeah, you're right. Alexander Friedman, we were chatting about off air, you know, he came up 100 years ago, 1922, with the initial framework for what would later become known as the Friedman Equations, which are the derivation from Einstein's theory of general relativity. That the universe can either expand or contract, but it can't really be static unless you put in, as Einstein did, a fudge factor, which he called the cosmological term, or the vacuum term, the lambda term. And he was steadfastly in opposition to these predictions refined by George Lemaître later on.

• 22:19Speaker 02

  In fact, Einstein said famously, "Your mathematics is exquisite," Lemaître and Friedman, "but your physics is atrocious." You know, it's just one of the many blunders that Einstein had. You know, it's too bad, Neil, because he could have had a good career.

• 22:34Neil deGrasse Tyson?

  I know, I know, I know. But since at the end of the day, this cosmological constant was real, all right? And the dark energy term. What I like saying is that Einstein's biggest blunder was saying that that was his biggest blunder.

• 22:50Speaker 02

  That's right. Never admit, never admit.

• 22:53Neil deGrasse Tyson?

  He's so badass that even when he was wrong, he was right.

• 22:56Speaker 02

  That's right. And we're still finding things out about him, that he predicted and now are only now being verified. Yeah, that's true.

• 23:04Neil deGrasse Tyson?

  Exactly, exactly. So Matt, give me some more, dude.

• 23:07Matt Kirshen?

  This is great. By the way, there's a bunch of people's questions that have been answered just in the process of you answering other questions. So I hope people feel satisfied with that.

• 23:15Neil deGrasse Tyson?

  Let's hear their names anyway, just.

• 23:17Speaker 02

  Okay, thanks a lot, guys. I'll talk to you later, I gotta go.

• 23:20Neil deGrasse Tyson?

  No, let's hear their names anyway.

• 23:21Matt Kirshen?

  Yeah, Rebecca Fuss asked a question about, why would space suddenly inflate? And what makes it inflate, which you answered.

• 23:29Neil deGrasse Tyson?

  Check box there, yeah.

• 23:30Matt Kirshen?

  Yeah, but Jeff Hunt says, "As a layman, I understand the cosmic microwave background radiation to be the echo of the radiation from the moment the universe starts to cool. What is our current understanding of what existed before the temperature dropped enough for it to become visible?"

• 23:45Speaker 02

  Ah, so that's another very astute question. So the CMB, or cosmic microwave background, are the oldest photons in the universe. So what we want to do is explain, where do those photons come from? And why did we just get to see them as they were 380,000 years after the Big Bang?

• 24:04Speaker 02

  So those photons-

• 24:04Neil deGrasse Tyson?

  Yeah, I want to see them 379,000 years after the Big Bang, okay? So come back on the show when you can tell me that, alright?

• 24:12Speaker 02

  Yeah, you need a time machine, and luckily we have telescopes like this, time machines, or telescopes or time machines, alright? So, when we look at the CMB, we ask, "Where did those photons come from?" And then, of course, we're gonna ask, "Where did the matter and the plasma that made those photons, which is what they are originating from, where did that come from? Where did the thing that came before, where did the inflaton come from?" I'm sure one of your audience is gonna ask me that, right? So that's what we do in science, and we may come to a point where we have to throw up our hands and say, "We don't know." But we're not ready to do that yet, because in a sense, we haven't reached the limit of what data can tell us. So, the answer to the, directly answer to the question is, those photons are the leftover

• 24:51Speaker 02

  heat that come from the fusion of hydrogen and its isotopes into helium, lithium, beryllium, and the lightest, you know, five or six different elements on the periodic table. That occurred in the first few minutes after the Big Bang. And then, there was really a plasma, that the universe was too hot, right after you nuclearly fuse, and that's not a word, but you fuse together two protons, you are left over with enormous amounts of heat. That's how the sun produces so much heat and light. Well, that heat and light doesn't allow atoms to form. So, an atom is a bonding of a proton and electron, that makes a hydrogen atom. So, the nucleus of hydrogen is proton, and then the electron come together. The universe was simply too hot, it was being zapped by photons.

• 25:35Speaker 02

  Anytime a hydrogen atom deigned to form, it would get immediately zapped apart, ionized, as we say. And that occurred until the heat cooled off due to the expansion of the universe, and that took 380,000 years.

• 25:49Neil deGrasse Tyson?

  Yeah, so what did the universe look like before that?

• 25:51Speaker 02

  It was an opaque plasma. It was essentially two plasmas, a plasma of, which is the fourth state of matter, it's a purely conductive medium, made up of pure protons or pure electrons, charged particles, and charged particles are opaque. So, a mirror is actually not a bad representation of a plasma. Plasmas reflect all the photons, and they, if there's enough plasma in three dimensions, unlike a mirror, which is two-dimensional, then the plasma will just keep reflecting the light, and it's kinda like a cloud, or a three-dimensional mirror, if you will. The light can't escape.

• 26:22Neil deGrasse Tyson?

  Normally, when we think of opaque, we're not thinking of a glowing object. So, this is-

• 26:27Speaker 02

  Right.

• 26:27Neil deGrasse Tyson?

  This is a, a full three-dimensional glowing-

• 26:31Neil deGrasse Tyson?

  Thing that is the universe that you can't see through, much like, I guess, the sun. Can't see through the sun.

• 26:37Matt Kirshen?

  Yeah, because it just traps any light that tries to, any light photons that hit it are just gonna bounce around or just be.

• 26:44Speaker 02

  Yep, yep, it'll be bouncing around. So plasmas are opaque, but neutral atoms are transparent. So, once hydrogen could form, the universe went from a plasma, two plasmas, as I said, to a single gas of hydrogen. And that took about 380,000 years. It didn't happen instantaneously, like, it's much like a condensation process. You have steam in a shower, if you ever go to a steam shower, you can't see through the steam, it looks like a fog.

• 27:08Neil deGrasse Tyson?

  None of us have ever showered. Uh, yeah, so you better give an example there.

• 27:12Speaker 02

  Okay, I'm glad we're not doing this in person, Neil. I'm glad we're not doing this in person.

• 27:15Neil deGrasse Tyson?

  I've never seen a steam shower. Of course we've seen, what kind of que, what?

• 27:19Speaker 02

  Have you ever been to a Turkish bath?

• 27:23Neil deGrasse Tyson?

  We all have good hygiene, I think, in my audience here, but go on.

• 27:27Speaker 02

  So, uh, you know, if you have a steamy shower and then you turn on cold water, the water vapor condenses and makes liquid, and then you can see in the shower. So, that process, the analog of that process is the formation of hydrogen. Then the universe became transparent, and we see those leftover photons, which have their beginning in the fiery cauldron that produced the first elements on the periodic table.

• 27:47Neil deGrasse Tyson?

  So, I, I, I think it'd be a cool trick if you could turn the sun into a transparent ball of gas, rather than the plasma that it is, and just watch that happen. And then it would just basically disappear, right? And you'd get to see what was behind it.

• 28:02Matt Kirshen?

  So you just throw some cold water in there?

• 28:03Neil deGrasse Tyson?

  Ah, that's all you need to do.

• 28:05Matt Kirshen?

  You just add a little bit of cold?

• 28:08Neil deGrasse Tyson?

  In the plasma shower.

• 28:10Speaker 02

  Don't forget, yeah, don't go at night.

• 28:11Matt Kirshen?

  Related to this, Eric Varga asks, "Why is there only one type of wavelength of light, microwaves, to see the cosmic background? Why do we not have ultraviolet, or gamma, or radio cosmic backgrounds?"

• 28:21Neil deGrasse Tyson?

  Love it, love it.

• 28:22Speaker 02

  These are great questions.

• 28:23Neil deGrasse Tyson?

  Go for it.

• 28:23Speaker 02

  So, I said that the cosmic microwave background, it is a relic at a temperature. I classified that by its temperature. The, the universe and the cosmic microwave background photons is an example of what's called a black body radiation source. A black body, these were first discovered and their properties were explained by Planck in 1900, and they are reflective of the fact that any object made of ordinary matter-

• 28:48Neil deGrasse Tyson?

  But don't use the word reflective in that sentence. Choose a different word, yes.

• 28:52Speaker 02

  Pun intended, Neil.

• 28:53Neil deGrasse Tyson?

  Okay.

• 28:55Speaker 02

  Pun without discretion.

• 28:56Neil deGrasse Tyson?

  They were absorptive, uh, yeah, no, go ahead.

• 28:58Speaker 02

  That's right.

• 29:00Speaker 02

  So they were, they are representative of the fact that you heat up anything, including an iron rod, or a ball of hydrogen and helium like the sun, to any temperature, it will emit a broad range of wavelengths. So in fact, there were originally wavelengths of light that were invisible because they were too short for the human eye to see. They were ultraviolet, they were equivalent to the energy that's required to zap apart a hydrogen atom into a proton and electron. So that, that energy level corresponds to a wavelength of light that was very small, but since the universe has been expanding, all the wavelengths in that black body, which kind of looks like a bell curve, the distribution of energy versus wavelength, the peak today

• 29:42Speaker 02

  has been redshifted by 1,000 times the, the value that it had when the hydrogen gas first condensed 380,000 years after the big bang. Not 380,000 years ago, 13 billion 800 million years ago. And so since that time, the universe has been expanding by a factor of 1,000, and it went from ultraviolet, and if you just do the math, ultraviolet wavelength, expand it by 1,000 times, you get about 2 millimeter wavelength, but that's just the peak. There are, there, it's like a bell curve. There are indeed photons of shorter wavelength and longer wavelength in the black body distribution.

• 30:14Neil deGrasse Tyson?

  So why doesn't anyone talk about them?

• 30:16Speaker 02

  Because there's, the, the peak is exponentially decaying on either side.

• 30:19Neil deGrasse Tyson?

  Okay.

• 30:20Speaker 02

  So you have massively easier time detecting the peak photons than you do the shorter or longer ones. But in fact, Penzys and Wilson did detect the short, the longer wavelength, less energetic photons, to almost 100, 50 times lower in energy than the photons that we detect today with our more advanced technology.

• 30:38Neil deGrasse Tyson?

  Okay, cool. So we could in fact have a cosmic radio wave spectrum, or a cosmic

• 30:44Speaker 02

  That's right.

• 30:45Neil deGrasse Tyson?

  Uh, infrared spectrum, but we don't reference it that way because the emissions in those band passes is meager.

• 30:52Speaker 02

  That's right, yeah.

• 30:54Neil deGrasse Tyson?

  Also, when we talk about the sun, the sun peaks in the visible part of the spectrum, but I think if you add up all the infrared coming from the sun, it's actually, we have more infrared than visible light.

• 31:04Speaker 02

  Yeah.

• 31:04Neil deGrasse Tyson?

  I think I did the math on that once.

• 31:06Speaker 02

  Yeah, that's right. And you can detect it with your hand with your eyes closed.

• 31:09Neil deGrasse Tyson?

  Yeah, I guess so. Yeah, there you go.

• 31:12Speaker 02

  What's that heat source?

• 31:13Neil deGrasse Tyson?

  Oh, yeah, yeah, yeah, there you go. All right, Matt, give me some more.

• 31:17Matt Kirshen?

  All right, so Jared Sober asks, Sober, rather, says, what do we make of the more recent data that seems to indicate inflation may not be as even as we thought? If so, is the new physics the same physics with slightly different implications or too early to tell? See, I think you answered the first part of that a bit earlier on, but...

• 31:37Neil deGrasse Tyson?

  Yeah, but I like that, so let me, let me add a little nuance to that question, Brian. So if the inflation is not symmetric, and I'm not up on that news story, but, but at what point do you say we just need to tweak the inflation rather than say, oh, my gosh, we need new physics?

• 31:54Speaker 02

  So that's one of these many cosmic controversies, as the Brits might say, that, that are...

• 31:59Neil deGrasse Tyson?

  This is America, Jack, okay?

• 32:02Matt Kirshen?

  Cosmic controversies.

• 32:03Speaker 02

  Don't break out the Bronx accent. Don't break out the Bronx. I'll break out my Long Island accent.

• 32:07Neil deGrasse Tyson?

  You don't have to, like, pretend you're gonna be British. No, this is America, Jack. You're from New York City.

• 32:12Speaker 02

  Mer. So when we do observe the cosmos, the first thing that you'd want to say is that the universe is isotropic, as I said before, but not perfectly isotropic. And it should be homogeneous, which means that it should be the same kind of physical properties everywhere in the universe, but it should also look the same everywhere you are in the universe on average. Okay, I can't tell you that every single star should look identical to every other single star in every direction you look, of course not. But our theory of inflation predicts that there should be an expansion of the universe, and only in kind of models that don't obey perfect cosmological symmetry, in other words, what's called the cosmological principle, which is an extension of what's called the

• 32:56Speaker 02

  Copernican principle, which is basically, I call it the cosmic big brother, that says, you're not special, you ain't so great, you know, it says that the Earth is not the center of the universe.

• 33:05Neil deGrasse Tyson?

  Somebody needs therapy. It's just, it's that.

• 33:09Speaker 04

  Mother.

• 33:11Neil deGrasse Tyson?

  Not all big brothers treated their kid brothers that way.

• 33:15Speaker 02

  I can only speak for how I treat my two younger brothers. So when we assume that the universe is on bulk scales, homogeneous and isotropic, that means that if we find a departure from that, we're really calling into question the underlying symmetries that we expect the universe to hold to. Now, I should say, there are alternatives to inflation, which have caused even more controversy, that people believe that inflation is not only incorrect, not only not good science, but there are even those that say it is bad for society to accept inflation.

• 33:55Speaker 02

  So, this rose to a head in 2017, when a Scientific American article was published by my friend Anna Agis, Paul Steinhardt at Princeton, the two of them, and Avi Loeb, who's at Harvard, and they published an article in Scientific American, said the universe inflation leads to this concept called the multiverse. And the multiverse, to them, this is their opinion, spelled the end of the scientific method. Because in the multiverse, it literally means that I have a podcast called Likely Science, and that Matt has a podcast called Probably Impossible, and Neil has Talk... Anyway, it says everything that possibly can happen, according to Linde, Guth, and others, does happen in this capacious universe.

• 34:40Speaker 02

  So, they claim, these three authors claim it was inconsequential, inconsistent with the scientific method. Then, there was a letter written by 30 Nobel Prize winners, and Guggenheim fellows, and a responsa to it, David Kaiser, and Alan Guth, and many others.

• 34:54Neil deGrasse Tyson?

  Geek fight, geek fight.

• 34:56Speaker 02

  It was a fight, it was incredible. I couldn't believe it.

• 34:59Neil deGrasse Tyson?

  On the pages of Scientific American, alright.

• 35:01Speaker 02

  It was like the Inquisition. And they said, "This is wrong, you're not scientists, no, you're not scientists."

• 35:06Neil deGrasse Tyson?

  But just to be clear, that original letter, that group were espousing a completely different model for the universe than what is currently here. So, they... So they already, we already peeked their whole card, right?

• 35:21Speaker 02

  Right, exactly.

• 35:23Neil deGrasse Tyson?

  Well, they're gonna write a letter. What do you think's gonna be in the letter? Or they're gonna say everybody else is wrong and they're right. That's right. We're gonna take another break. And when we come back, let's try to like do maybe a lightning round. Matt, do you think Brian has that in him?

• 35:36Matt Kirshen?

  I think he does. We've got, this is, I think even still, we're not gonna get through all of them because this was one of the most popular.

• 35:42Neil deGrasse Tyson?

  One of the most popular. Yeah, you know, I don't think Brian has it in him. He's got a, he's a mixture explainer there. We'll see how he does on a soundbite mode. All right, when StarTalk continues.

• 36:06Neil deGrasse Tyson?

  We're back. StarTalk Cosmic Queries: Cosmology, Early Universe Edition with Brian Keating. And Brian, you do a lot of stuff for the public. I was very impressed to see you visit high schools, you've written books. You're, so you're a man about town, bringing your, your expertise to all those who will listen. And you do it well enough so that that's a growing supply of people. Because you could, you could bring it to all will listen today. That could get halved every day if you really suck at it. So very good to see that this is a growing.

• 36:44Speaker 02

  Yeah, I'm a little controversial because I say I believe that scientists such as myself have a moral obligation to give an explanation to the public.

• 36:53Neil deGrasse Tyson?

  I don't think that's controversial, so, you know.

• 36:56Speaker 02

  Well, I mean, my colleagues think it is. I mean, they say, well, why are you wasting your time on the YouTube channel?

• 37:01Neil deGrasse Tyson?

  Yeah, of course they're gonna say, of course they're gonna say that. Of course they're gonna say that. Okay, we are not among those who feel that way about you.

• 37:07Matt Kirshen?

  Because your YouTube channel's doing better than theirs.

• 37:09Neil deGrasse Tyson?

  No, that's exactly.

• 37:11Speaker 02

  I would kill for them to, I would give them my following.

• 37:13Neil deGrasse Tyson?

  They don't even have a YouTube channel. That's what the problem is.

• 37:16Speaker 02

  That's the problem.

• 37:17Neil deGrasse Tyson?

  All right, lightning, lightning mode. Let's do this.

• 37:20Matt Kirshen?

  All right, let's crank some out then. Here we go. Don Lane asks, how much will the expanding nature of the universe figure into interstellar navigation computations?

• 37:28Speaker 02

  Absolutely negligible. The universe is expanding less than about one second per century on the appropriate scales. It will not be observable in your lifetime, let alone in a navigational, you know, kind of trajectory. So, you know.

• 37:43Neil deGrasse Tyson?

  So, any place you want to go to before you die is way less than any time of significance with regard to the expanding universe.

• 37:49Matt Kirshen?

  All right.

• 37:49Neil deGrasse Tyson?

  Good. There it is. Nice one.

• 37:51Matt Kirshen?

  Let's go. Chris Hampton says, could our universe be expanding because it is filling with spacetime fluid? And could the reason it keeps accelerating be because there are more, quote, "forcets" opening up?

• 38:03Neil deGrasse Tyson?

  Okay, so Brian, who left the spigot on the universe?

• 38:07Speaker 02

  Of course, my wife. It's always me, Neil. It's always me. Yeah, actually, the answer is very, the question is very perceptive because essentially the notion of the dark energy, which is the responsible party for the accelerating universe. Not only is the universe getting bigger every day, the rate at which it's getting bigger is getting bigger every day. Therefore, we have a time derivative of a velocity that's called cosmic acceleration. So, we equate that.

• 38:34Neil deGrasse Tyson?

  But it's called just acceleration, and this is applied to the universe, cosmic acceleration. There you go.

• 38:39Speaker 02

  Yes, exactly. Right. So, indeed, this substance has what's called an equation of state, and that equation of state is a relationship between a substance's pressure, when you try to compress it, versus its density, how many ergs per cubic centimeter, how much energy there is per cubic centimeter. So, actually, the flubber-like material, it's not a fluid, the dark energy, we don't know exactly what it is, but we know what it is not. It's not a fluid like water. Water has very different pressure-density relationships. But it has a strange relationship, which when you try to compress it, it says, oh, okay, great. Instead of resisting it like water would, it says, oh, I love this, let me suck you in. And it's kind of like an anti-gravitational force. So, it's not fluid

• 39:22Speaker 02

  like water, but it is filled with an equation of state. And if you say it like that, you sound more erudite, and you'd be correct.

• 39:27Neil deGrasse Tyson?

  The answer is yes to this question, and it is a spacetime fluid, not a traditional fluid that we might otherwise think of. Okay, there you go. Keep it going, man.

• 39:37Matt Kirshen?

  Okay. Alejandro Reynoso says, "Hola from Monterrey, Mexico. And what new discoveries do you think we can get from the BICEP project?"

• 39:46Speaker 02

  Ah, so the Bicep Project is a project I started way back in 2001. We built a polarimeter, which is a telescope.

• 39:53Neil deGrasse Tyson?

  But first, why, why, what, bicep? What, what, what is, what, where's that word come from?

• 39:56Speaker 02

  So, bicep is a corny name that I came up with. It stands for background imager of cosmic extragalactic polarization. So, I said that inflation is not proven, but there is one signal which we would hope to detect, and it's called gravitational radiation, or waves of gravity produced by the violent shaking and shuddering of spacetime. Einstein predicts that will cause waves of gravity to percolate throughout the cosmos.

• 40:18Neil deGrasse Tyson?

  So, have we found it with LIGO? Are they looking for you?

• 40:20Speaker 02

  No, LIGO cannot see this. It's way too weak because the universe is expanded by a factor of trillions and trillions of times since the inflationary epoch. We can only see it with a, with a microwave telescope to look at the imprints of these waves on the CMB. We're using the CMB, Neil, as the detector. That's so phenomenal of us.

• 40:38Neil deGrasse Tyson?

  Okay, so you can't, you can't, you can't measure A, but you can measure A's effect on B because you can measure B?

• 40:43Speaker 02

  Yep.

• 40:44Neil deGrasse Tyson?

  Oh, that's very tricky.

• 40:46Speaker 02

  We're putting our detector right at the source. So, in 2001, I came up with an experiment with colleagues at Caltech, which we called Bicep. Like I said, it's the subject of this book, Losing the Nobel Prize. And that's it, right there, if you're watching on the, on screen. Otherwise, I'm showing a picture of our telescope at the South Pole, Antarctica, where I've been twice. We put a telescope there, and we've upgraded it ever since. In 2014...

• 41:04Neil deGrasse Tyson?

  But just to be clear, the address of the South Pole is South Pole, comma, Antarctica? That's what that sounded like?

• 41:10Speaker 02

  Or you can send it to negative 90 degrees, negative 90 degrees. It actually has a post office, and you actually have a gift shop there.

• 41:17Neil deGrasse Tyson?

  Negative 90 degrees, and any longitude will do, right? Because they all converge.

• 41:21Speaker 02

  All, every direction leads north.

• 41:23Neil deGrasse Tyson?

  At the South Pole. Okay. So, was it successful? We're still in soundbite mode here. So, that was 01, that was 20 years ago, so...

• 41:29Speaker 02

  Yeah. So, Bicep made an announcement, 2014, we detected inflation, we detected these waves of gravity. Turned out, we detected cosmic dust, particles of dust in our galaxy, not the imprimatur of inflation.

• 41:41Neil deGrasse Tyson?

  Oh, my God, stuff sitting on our nose in our own galaxy. Oh, okay.

• 41:44Speaker 02

  But Bicep is still flexing away, and so is its, its, its other, I'm the, the project I lead now with my colleagues called the Simons Observatory, which is going to be the most advanced cosmic microwave background experiment.

• 41:55Neil deGrasse Tyson?

  Named after Jim Simons, right? The wealthy investor.

• 41:57Speaker 02

  That's right, Jim and Marilyn Simons.

• 41:58Neil deGrasse Tyson?

  Who's very, very into science and math, which is a good thing. All right, man, let's keep going.

• 42:04Matt Kirshen?

  All right, Ruhan Periachary asks from the Bay Area, says, "Is it possible that a new universe is born every time another universe dies, say via Big Rip or Bounce? We say multiverse like there are multiple universes existing parallel to us in some higher dimension, but what if that higher dimension is actually time itself?"

• 42:21Speaker 02

  Hmm, very good, yeah. So in fact, there are multiple versions of the multiverse, as kind of this question is hinting at. There's a quantum mechanical multiverse, there's a many-worlds multiverse, there's cosmological multiverse, but also, there is an alternative to inflation, which avoids the multiverse problem, and that's called a cyclic or bouncing cosmological model, which does feature a universe collapsing, if you will, to create our universe that we see. And there's no reason that couldn't happen multiple times in multiple places throughout the universe. So it's exactly correct.

• 42:53Neil deGrasse Tyson?

  All right.

• 42:54Matt Kirshen?

  I'm going to combine these two questions, because these are two things that I struggle with conceptually. Daniel Kalakowski, sorry, Kalakowski, rather, says, "If the cosmic microwave background is radiation expanding outward from the Big Bang, how are we able to see the light here on Earth? Wouldn't the radiation be traveling towards the edges of the universe, and that's not visible to us? Thanks for helping me understand this." And then also, Robert Weaver from Michigan says, "I understand it's not possible to see beyond our cosmic horizon, as light has had not enough time to travel to us. If that is true, and space is expanding faster than light, are we forever landlocked in regards to the observable universe? No matter how fast we go, the edge is traveling faster away from us, so we never see more than we do now, but actually less as time goes on."

• 43:38Matt Kirshen?

  So I don't know whether those two are connected or not, but they felt conceptually connected, so I checked them both at you together.

• 43:43Neil deGrasse Tyson?

  Yeah, yeah. Brian, what can you do for us here?

• 43:45Speaker 02

  All right, so imagine two observers, Albert and his evil twin, and they separate faster than the speed of light. As long as they started out closer in distance, such that their light could have, when this light was launched from one of the two observers, it could have maintained its velocity and trajectory towards the other observer. It doesn't matter how far away that thing is now. We look at when it was emitted, when it was detected, and it doesn't matter where that galaxy is now. So it is true, there is a whole branch of objects in the universe. In fact, I did a calculation for my cosmology class, which I'm going to teach in a few minutes. And that showed that 97% of the universe by volume is causally disconnected, can never communicate, landlocked, in the words of your poetic.

• 44:27Neil deGrasse Tyson?

  I love the reference, yeah.

• 44:29Speaker 02

  Yeah, so that means that, yeah, we can't see those objects. It doesn't mean we couldn't see them in the beginning, because in the beginning, they were not expanding, they weren't at redshift greater than 1, as cosmologists call it. So indeed, we can still see them, but we can never access them. And there's a difference between being able to see their original emission and being able to contact them now. So exactly correct, they are isolated from us by a cosmological event horizon.

• 44:51Neil deGrasse Tyson?

  Brian, you're doing good here.

• 44:52Matt Kirshen?

  And then the second part of how can we see the cosmic background radiation if the universe is expanding away from us?

• 44:58Neil deGrasse Tyson?

  Yeah, let me reword that, as I think I understand it. If 380,000 years ago, all these photons were set free, well, they should be in some way beyond us today, en route to exit the universe, or whatever, why are they still headed towards us?

• 45:16Speaker 02

  Well, so the photons are traveling towards us, and at the time of their emission, we work physically closer to them. And since that time of emission, the time at which the CMB was formed, the universe expanded by a factor of 1,000 times. So a photon would have been within our cosmic horizon, would have been able to access us, just like any object that's at a redshift greater than 1. You could ask that question of any object, the CMB is at a redshift of 1,100. So the answer is similar to the answer I just gave. It launched the photons such that they will reach us with the exact trajectory just reaching us now, and the process of this formation of the CMB was not instantaneous, and we will continue to see those photons, but caveat, that we won't see them with the wavelength that they were originally.

• 46:00Neil deGrasse Tyson?

  As we described earlier in the show. So what you're saying is, it was en route to us today from the beginning, is what you're saying?

• 46:08Speaker 02

  Yes, we were in its future light cone.

• 46:10Neil deGrasse Tyson?

  Nice, nice. So it moved not only through space but through time? As of course these things go. Alright, Matt, keep it going.

• 46:16Matt Kirshen?

  Alright, Megan Munoz says, "Is it possible that space is created in a black hole? I have this weird theory that the matter that goes into a black hole may be torn apart so much that it literally turns to space. And I mean, not only does the object disintegrate, but in the process, more space is created than was originally taken up by the mass. Maybe that's why space expands. That is, if the new space could make it outside of the black hole, can I have a scholarship? Has Megan done enough to get a professorship from one of you?"

• 46:43Neil deGrasse Tyson?

  So Brian, if he has any answer other than "I don't know", let's ask him, "When was the last time he visited the inside of a black hole?" Okay, go Brian.

• 46:51Speaker 02

  The shower, exactly. So, right, so I get about 10 letters a week saying, you know, Einstein was wrong, I can prove it, but I'm not good at math, so can you share the Nobel Prize with me?

• 47:02Neil deGrasse Tyson?

  You do the math and you figure it out, and right.

• 47:04Speaker 02

  That's right. I'll keep the Nobel Prize, thank you. So, no, we have no evidence for that. It doesn't mean it's not possible. There are people that do predict that time is created when black holes at the, beyond, inside the event horizon, singularity. But we have no way to access it. It is beyond the event horizon. So even if it did get produced, like Hawking radiation, we've heard about Hawking radiation undoubtedly, that radiation exists, but it's so impossible, even in practice, to envision detecting it. It's all but irrelevant, as is unfortunately, your new theory. Sorry, scholarship revoked.

• 47:38Neil deGrasse Tyson?

  Damn. That was a smackdown if I ever heard one.

• 47:45Speaker 02

  At least take me out for a drink before you ask me for a scholarship.

• 47:47Neil deGrasse Tyson?

  Oh, man. Man, Matt, I don't know, I don't think we have any time for anymore, Matt. Do we leave a lot on the cutting room floor?

• 47:53Matt Kirshen?

  Oh, there are so many good questions, yeah. You could do a whole, you could do a whole second, maybe even three episodes of Cosmic Curiousness.

• 48:00Neil deGrasse Tyson?

  We will totally have to do another episode on this. Well, Brian, it's been great having you on. I think, I think your first time on StarTalk, and but...

• 48:08Speaker 02

  It is my first time, yeah.

• 48:10Neil deGrasse Tyson?

  It's not the last. And, and Matt, you're a comedian, so is that what you do at nights? After sunset.

• 48:19Matt Kirshen?

  Yeah, that's the after dark job. So yeah, I post what shows I'm doing on Twitter, at Matt Kirshen. And then probably Science is the podcast and I mentioned my shows on there as well.

• 48:29Neil deGrasse Tyson?

  And you do stand up. So if you want to find you, find out what city you're in, we can find you.

• 48:33Matt Kirshen?

  Exactly.

• 48:34Neil deGrasse Tyson?

  On your website. And Brian, how can we find you in the social media pantheon?

• 48:39Speaker 02

  I'm at DrBrianKeating, Twitter, Instagram, and my website, BrianKeating.com. If you join my mailing list, I will send you all a piece of space dust. A meteorite from the origin of time and space itself. BrianKeating.com is the way to find me.

• 48:53Neil deGrasse Tyson?

  That's a little suspicious there, but okay, I'll let you have that.

• 48:57Speaker 02

  I don't see how big the space dust is.

• 49:01Neil deGrasse Tyson?

  Isn't all matter in some level, space dust?

• 49:05Speaker 02

  That's true. As Carl Sagan said, "We are a rockamote of dust floating on a sun."

• 49:09Neil deGrasse Tyson?

  Yeah, yeah, there you go.

• 49:10Speaker 02

  Pale blue dot.

• 49:12Neil deGrasse Tyson?

  All right, guys. This has been StarTalk Cosmic Queries, the cosmology edition. Clearly, we're going to have to do some more of these. Brian, good to have you. Matt, always good to see you as my co-host.

• 49:22Speaker 02

  Thanks, my friend.

• 49:23Neil deGrasse Tyson?

  Neil deGrasse Tyson, your personal astrophysicist. Keep looking up.