Neil deGrasse Tyson - Welcome To The Universe

Neil deGrasse Tyson is an astrophysicist, planetary scientist, author and science communicator. Elon Musk bought Twitter and I found out about a 300 million light year across supervoid out in space within the same week. Thankfully Neil is here to help me work out what is going on in this version of the simulation. Expect to learn whether focussing on Mars as a backup planet is a smart idea, how big the universe is outside of the observable universe, how we could restart the sun when it begins to die, when time will end, the politics of who gets to claim different asteroids, Neil's favourite solution to the Fermi Paradox and much more... Sponsors: Join the Modern Wisdom Community to connect with me & other listeners - https://modernwisdom.locals.com/ Get 30% discount on your at-home testosterone test at https://trylgc.com/modern (use code: MODERN30) Get over 37% discount on all products site-wide from MyProtein at https://bit.ly/proteinwisdom (use code: MODERNWISDOM) Get 20% discount & free shipping on your Lawnmower 4.0 at https://www.manscaped.com/ (use code MODERNWISDOM) Extra Stuff: Buy Welcome To The Universe in 3D - https://amzn.to/3EWjD5b Follow Neil on Twitter - https://twitter.com/neiltyson Get my free Reading List of 100 books to read before you die → https://chriswillx.com/books/ To support me on Patreon (thank you): https://www.patreon.com/modernwisdom #neildegrassetyson #space #universe - 00:00 Intro 00:28 Should Elon Musk be Focusing on Mars? 08:48 Models of Astro-Politics 11:06 The Fermi Paradox 19:10 How Big is the Universe? 24:17 Why Plank Length Exists 31:04 Leaving the Milky Way 38:39 Neil’s Upcoming Work - Join the Modern Wisdom Community on Locals - https://modernwisdom.locals.com/ Listen to all episodes on audio: Apple Podcasts: https://apple.co/2MNqIgw Spotify: https://spoti.fi/2LSimPn - Get in touch in the comments below or head to... Instagram: https://www.instagram.com/chriswillx Twitter: https://www.twitter.com/chriswillx Email: https://chriswillx.com/contact/

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

• 0:00Speaker 00

  But if you're gonna say we need to put our eggs in two baskets instead of one, so that when a disaster hits one planet, everyone else can just watch it and watch half their species die and somehow be okay with that, rather than prevent it from happening in the first place, if you're okay with that, then fine. But I'm saying fix the problems that you don't even have that problem you're trying to escape.

• 0:24Chris Williamson?

  Neil deGrasse Tyson, welcome to the show.

• 0:26Speaker 00

  Yeah, thank you. Thanks for having me.

• 0:28Chris Williamson?

  Elon's bought Twitter, Neil. Should he be spending his time and money taking people to Mars? What's going on?

• 0:34Speaker 00

  Yeah, I've stopped passing judgment on what billionaires do with their money. I mean, think about it, he could just be having a yacht contest for who has the biggest yacht. You know, billionaires have whatever are their habits, and I don't know that any of us would behave any differently if we had billions of dollars. So I've just stopped commenting on what a billionaire billionaires do do or should do with their money. What I can say is if a billionaire is gonna do something, it's kinda interesting that he single-handedly brought electric cars back into, uh, he created a new expectation for

• 1:15Speaker 00

  the automotive industry, basically, single-handedly. And he reinvented commercial rocket launch. So he was doing that with his billions, and he has 44 billion left over, and he wants to own Twitter, which he likes, all right? I don't see anything wrong with that. By the way, most things out there have CEOs who you don't know, and you don't even ask. We just happen to know who the new CEO of Twitter is about to be, and so now this becomes a point of conversation. Why isn't anybody talking about the head of any other organization

• 1:51Speaker 00

  or company or strategic platforms of communication? So I think the level of scrutiny is is unjustified, given how much scrutiny we could be giving to so many other things. But that being said, if he does what everyone fears, especially on the left, that he reopens the floodgates, gives Trump an account again, um... I think we need to perhaps look at it a different way. Free speech is a... What you want is to not suppress the speech that you don't like, but amplify the speech that you do.

• 2:32Speaker 00

  And let that be the arena of contest of ideas. Because if you suppress ideas, those ideas will still always be there and they'll run around saying, "I have this idea, but these folks don't want to hear it." That's very different from you losing the idea game in an open contest. And then you say, "Well, how comes nobody's listening to you?" "Yeah, because they turned me off." "Because they shut off the channels where I was communicating, because they don't want to hear anything that I have to say, or because everything I said is wrong." All right?

• 3:13Speaker 00

  These are two different ways emergent truths can win. But you want it to be the second way because then no one has a platform left. If it's a platform that is either regressive,

• 3:29Speaker 00

  puts us all at an existential risk, or whatever, let it lose on its own terms.

• 3:35Chris Williamson?

  Speaking of existential risks, how good do you think Mars is as a backup to humanity? One of the problems-

• 3:41Speaker 00

  What you want to back up?

• 3:43Chris Williamson?

  Well, the fact that we only have one cradle at the moment, right? If something goes wrong here, if we're all being slowly turned into paperclips or gray goo or there's a bioweapon that gets released or whatever, we don't have some air-gapped backup.

• 3:56Speaker 00

  I assume your listeners know what you mean when you say we're all getting turned into paperclips.

• 4:01Chris Williamson?

  Yes, they do.

• 4:02Speaker 00

  They do. So they're AI fluent, is that correct?

• 4:05Chris Williamson?

  AI fluent? Yeah, that's all one word as well, AI fluent. Yes. Yeah, they are. So they know Nick Bostrom, they know about existential risk.

• 4:13Speaker 00

  Paperclip hypothesis.

• 4:13Chris Williamson?

  Yes.

• 4:14Speaker 00

  So, so, um, yeah, or an asteroid or a virus, whatever.

• 4:19Chris Williamson?

  Or anything.

• 4:20Speaker 00

  Yeah, so here's my- rebuttal to that. And by the way, this rebuttal is, I don't know many people who have this rebuttal. So this may just be an outlier in the examples you're collecting. But right now Antarctica is wetter and balmy than any place on Mars. Yet I don't see people lining up to build condominiums there. All right, it's a wholly inhospitable place. Right now it's used for some tourism, but mostly for scientific research. If you want to move to Mars and do it in a way that's not having you confined to a habitat module, you'll want to terraform Mars.

• 5:03Speaker 00

  And that's turning Mars into Earth and then ship a billion people there. So here's my thought. If you have the power of geoengineering to turn Mars into Earth, then no matter what is about to happen on Earth, no matter what did happen on Earth, you have the power to turn Earth back into Earth. And so I don't see Mars as a realistic backup plan. Because whatever you'd have to do to Mars, you could do to Earth. And then that's your backup plan on Earth.

• 5:36Chris Williamson?

  Would it be more difficult to terraform Mars than to perhaps survive a huge asteroid impact? Or to combat some rogue AI?

• 5:44Speaker 00

  No, no, you deflect the asteroid. What, dude? We're talking, if we can fly to Mars and terraform it? Fly to Mars, ship a billion people there? I think we'll know how to deflect an asteroid. Okay?

• 5:56Chris Williamson?

  Okay.

• 5:56Speaker 00

  Am I, am I on a limb there when I say?

• 5:59Chris Williamson?

  No, I don't think that you are. But my point is that there may be some existential risks, which are so existential or so difficult to overcome, that the Mars terraforming could be easier than it would be.

• 6:09Speaker 00

  There's none that I can think of at this moment, but yes, I will allow that possibility. But there is none I can think of. Okay, so how about a killer virus that'll take us all? Let's invent an antiviral serum that'll take out any virus. All right, that's, is that a stretch to imagine? It's less of a stretch than flying to Mars, terraforming it and shipping a billion people there.

• 6:32Chris Williamson?

  Fair enough.

• 6:32Speaker 00

  No matter what you come up with, it's less of a stretch of my imagination as a problem to solve than terraforming Mars and ship a billion people there.

• 6:41Chris Williamson?

  That's how big the problem is to do it.

• 6:44Speaker 00

  Yeah.

• 6:45Chris Williamson?

  The Mars problem is.

• 6:46Speaker 00

  Because we don't know how to terraform yet. We don't know how to terraform. I think we could build a habitat module. Sure, we can figure that out.

• 6:56Speaker 00

  Yeah, but how many people are going to live there? And you have to bring supplies, have to have supply ships. So, but still to do that, there's a lot of science and technology and time and money. Just solve the problems here on Earth. Just solve them.

• 7:12Chris Williamson?

  So you're saying that Elon buying Twitter actually is the best use of his money rather than, and his attention rather than going to Mars?

• 7:18Speaker 00

  Oh, no, no, I'm not, I, I, I will not judge what people should or should not do with their money. Okay? So I will not say I'm glad he did this or that. What I will say is, and by the way, forty-four billion is a, is it fifteen percent of his wealth? Twenty percent of his wealth?

• 7:36Chris Williamson?

  Raised it from investors as well, yeah.

• 7:38Speaker 00

  Yeah, yeah, so, so.

• 7:42Speaker 00

  And by the way, that wealth, it's not like he doesn't have that money anymore. It's invested in a thing that has value. So it's not like you went to buy candy and you ate the candy and you don't have the money anymore. So, so I'm not going to sit here and pass judgment on how billionaires spend their money. Just not going to do that.

• 8:01Chris Williamson?

  Got you.

• 8:01Speaker 00

  I, I can tell you, he wants to terraform Mars. I don't have a problem with that. But if you're doing it because you think Earth needs a backup plan, that's the wrong reason. That's, that's kind of objectively false. It, not, let me say that differently. It's hard to defend it for that reason. You can defend it for other reasons. It's a cool thing to do. The technology demonstration, sure. But if you're going to say, we need to put our eggs in two baskets instead of one, so that when a disaster hits one planet, everyone else can just watch it and watch half their species die and somehow be okay with that, rather than prevent it from happening in the first place. If you're okay with that, then fine. But I'm saying.

• 8:43Speaker 00

  Fix the problems that you don't even have that solution you're trying to that problem you're trying to escape.

• 8:49Chris Williamson?

  Have you looked into astropolitics much? Who's going to own Mars? Who owns?

• 8:53Speaker 00

  Yeah, sure. I have some sense of that.

• 8:55Chris Williamson?

  Of space? That's that's so fascinating to me. You know, is it first come, first serve? Is it another? Is it the the new sort of colonialist era that we're going into now? You just get to stamp a little area out on Mars and it's yours?

• 9:08Speaker 00

  Yeah, so so the only successful, if we can call it that, model that we have for this sort of thing is homesteading. So if you so let's say the international community owns Mars. Let's just make this up as, you know, I'm Pope of the UN and I declare that like Antarctica, the international community has equal access. If you go there and pitch tent and figure out a way to make a buck, let's say you have a mining operations, whatever, then you get to keep that land, provided the industry you create accrues back to the rest of us in some way or in some form.

• 9:50Speaker 00

  So that has worked in the past, holding aside people taking land that belonged to others or, you know, and all the other issues that colonization brought with it. The simple fact of being the first on a plot of land and doing something with it, getting to keep that land if you manage to, as they say, develop it. That's a successful model in the past. I don't see why that wouldn't still be invoked with regard to asteroids, which have basically unlimited natural resources. If you're the first on an asteroid and you plant your flag, you keep the asteroid. There's hundreds of thousands of asteroids, no shortage of them to do this with, by the way. One of them actually has my name on it.

• 10:33Speaker 00

  So if I were ever to travel to one, I'd probably put that one top on the list.

• 10:36Chris Williamson?

  Which one?

• 10:37Speaker 00

  It's 13123 Tyson.

• 10:40Chris Williamson?

  Why? Did you find it?

• 10:42Speaker 00

  No, no, that is one way to have an asteroid named after you, if you find it. I'm not an asteroid hunter. But there's some, an asteroid hunter who was a big fan of my work and respected what I do and my efforts in the public. So in my honor, they named it, uh, one, one, three, one, two, three is the numerical sequencing. And then the name is just Tyson that follows it.

• 11:04Chris Williamson?

  That's pretty cool.

• 11:04Speaker 00

  They're very honored by that.

• 11:05Chris Williamson?

  Yeah, that's very cool. What's your favorite answer to the Fermi paradox? I spent an hour and a half last night having a discussion with a bunch of friends.

• 11:14Speaker 00

  Yeah, I think, um, well, this is my favorite answer, but I don't think it's the most realistic one. My favorite answer is they've already visited and have judged that there's no sign of intelligent life on Earth.

• 11:29Chris Williamson?

  Well, did they come, did they come last week?

• 11:30Speaker 00

  That's the simplest explanation. Another interesting explanation is that whatever is the urge to colonize as many planets as you can, which is what the Fermi paradox, that's the foundation of the Fermi paradox, right? You have a civilization and it travels to nearby planets around other stars. And, and then they then travel to two other planets and they travel to two. So there's a, a quick doubling time where in, where you can populate the entire galaxy in just a few hundred thousand years.

• 12:13Speaker 00

  And that's small compared with the history of life on Earth. That's even small compared with the anticipated life expectancy of mammal species, which last I checked, it is up around three million years. So, but there's an interesting self-limiting fact, which I'm going with in my explanation here. It's whatever urge it takes for you to colonize a planet. If that is a genetic driver in an entire wave of people who are colonizing the galaxy, then at some point you're going to want to colonize the same planet that I do.

• 12:59Speaker 00

  And you're not going to take no for an answer. Neither will I. That's what got me here to where I am right now. So we will then fight.

• 13:11Speaker 00

  Until one person wins and one person loses. And that will happen at every turn. When the number of planets that can be colonized begins to drop relative to the ones that have been. And you'll get infighting. And the entire system implodes. By the way, that kinda already happened in Europe. Portugal rises up, Spain rises up, France rises up. England rises up. They have these powerful navies and they want to colonize the world. And in the end, what do they end up doing? Fighting each other. Over who owns what colony in the world. So it could be that the very urge to do that is self limiting.

• 13:56Speaker 00

  Very urge to populate every planet. Is the very same force that would prevent that from happening in the end.

• 14:04Chris Williamson?

  That's an interesting way to look at it. One thing I've always considered is that I think it would be difficult for any civilization to be more emotional than we are. If you were to tune the intensity of our emotions up, our reactivity, our anger, our sadness, our despondency, whatever. If you were to tune that up by another 15%, I think coordination becomes so difficult that you really, maybe not 15%, maybe 25 to sort of 30%. I think it's so difficult that you can't achieve anything, which is wild to think that we're near to perhaps the limit on how emotional a civilization could be and still not be completely ineffective.

• 14:43Speaker 00

  Except we have a very big range of expressed emotion among us within the species. So I don't know that I could characterize, yes, I agree, we're an emotional species. I'm not denying that. But the people who make decisions, who allocate monies, who fund research and discovery. I don't necessarily think that emotions are as forceful as you are implying.

• 15:07Chris Williamson?

  Cause they have constraints, they have rules, guidelines, procedures, checks and balances.

• 15:12Speaker 00

  Right, right. And things get debated and decisions get made. All right, we didn't discover the Higgs boson based on emotion. Right, um, the, uh, what else? We, I guess we can say we went to the moon based on emotion because we were a little spooked by the Soviet Union, but it took, in the end of the day, science and technology to accomplish that. You can't wish stuff or pray stuff into space. So, so I, I like where you're going with that, but I don't think it applies entirely with us.

• 15:43Chris Williamson?

  Well, that's what we try to do, right? That's the reasons we have rules and procedures in place in an effort to try and constrain some of those worst aspects, or else everybody would be making decisions purely based on emotion.

• 15:54Speaker 00

  Yeah, that's correct. Yeah, I, I agree with that. Mm-hmm.

• 15:57Chris Williamson?

  Do you think that we should be trying to message aliens? There's meti as well as seti, right? Messaging extraterrestrial intelligence. And I know that it's quite contested about whether that's a safe thing to do or not.

• 16:08Speaker 00

  Well, so, once again, it's like the terraforming Mars. Uh, it makes a good headline. You know, don't tell the aliens we're here because especially since we know in advance, without asking you, you are not going to give your email to a stranger on the street or your home address. You're just not going to do that. And this is another person who's our own species. They're, they're your species and you're not giving them your return address. Now we're talking about giving our return address to aliens out in the galaxy. And that's, so whatever distrust you have of your fellow species, you think that should be magnified as a distrust of, um, aliens. So I, I get that. And I don't have a problem

• 16:53Speaker 00

  with that, except aliens already know where we are. We have an 80-year radio bubble of radio signals that came from TV sets, that came from broadcast antennas, and...

• 17:11Speaker 00

  This is 80 light year radius, expanding at one light year per year, is a radius of radio information about our species and about our culture. So aliens can learn practically everything they'd want to know, even if it's not everything they'd need to know, in our television broadcast shows. So the honeymooners, they learn how men interact with women. They might, you know, see the Flintstones and wonder what's going on there. So, so, yeah, this, to be worried about a signal being sent today, when signals are

• 17:50Speaker 00

  being sent inadvertently for the past 80 years, I think is misguided concern.

• 17:57Chris Williamson?

  Because we've already let that horse bolt out of the gate.

• 18:01Speaker 00

  Correct.

• 18:02Chris Williamson?

  Interesting, yeah, I am, I wonder, I'm really not, not sort of too convinced by the concern about messaging. You're right, anyone, any civilization that we should be sufficiently scared of because they're going to come and try and destroy us, has probably already been able to detect that we're here. And it does seem a little bit like looking at a teacup in, out of an ocean and going, look, well, there's nothing in here, we know that there can't be anything out there. That's the equivalent temporally with how long we've been around. We've been around, what, 50,000 years, when we could have actually written stuff down and it might be in a cave somewhere or whatever. Like, there's been a significantly longer period of time that aliens could have been and gone and decided that they're not bothered with this planet.

• 18:43Speaker 00

  Yeah, and plus, if you're listening in for radio signals, if they listened in 2,000 years ago, we would have had the Roman Empire. By anyone's measure, that's civilization, or the Egyptian Empire, 1,000 years, whatever, before that. And, but, if they don't have a radio signal to send back, you would think that there was no intelligent life here on Earth, when there clearly was.

• 19:04Chris Williamson?

  That's a good point. Technology and civilization have a lagging, a lagging measure, right? Talking about, talking about that bubble, I've been thinking about how, whether anybody has estimations about how big the universe is outside of the observable universe? Is there any way that this can be?

• 19:21Speaker 00

  Yeah, there's some estimates, but they're, it's like very loose estimates.

• 19:28Chris Williamson?

  What do you even base it on?

• 19:29Speaker 00

  Well, you can look at, um...

• 19:35Speaker 00

  So you can look at how big our universe is and how long it's been expanding and ask if you were randomly to come upon a universe, what is the likelihood of coming upon it within the first 14 billion years rather than the whole rest of its life? And so you make some, uh, some estimates along those lines and then you can conclude how much bigger the full universe is relative to how much time we've been expanding within it. And I free, I don't remember the estimates. It's, I actually, we, with the numbers in one of my recent books, it's in Cosmic Queries. We give the size that the universe could likely be beyond the visible horizon.

• 20:19Speaker 00

  I just don't remember exactly what the number was.

• 20:22Chris Williamson?

  I learned about the Boetius supervoid this week. Have you heard of that?

• 20:27Speaker 00

  Tell me the name again?

• 20:28Chris Williamson?

  Boet, it's B O.

• 20:30Speaker 00

  Oh, Boetius.

• 20:31Chris Williamson?

  Yeah, it's got a, whatever it's called, not an ampersand.

• 20:34Speaker 00

  Over the second O.

• 20:35Chris Williamson?

  That's it.

• 20:36Speaker 00

  Boetius supervoid.

• 20:37Chris Williamson?

  Yes.

• 20:38Speaker 00

  Yeah, it's a constellation. Um, and yeah, it's just a region of the universe where there's hardly any galaxies.

• 20:43Chris Williamson?

  Like 300 million light years across or something?

• 20:45Speaker 00

  Nothing big and interesting.

• 20:46Chris Williamson?

  Yeah.

• 20:47Speaker 00

  What's that?

• 20:48Chris Williamson?

  It's 300 million light years across, I think.

• 20:49Speaker 00

  Yeah, it's got, it doesn't have bright stuff in it. It probably has lighter, smaller things that are less visible. Uh, and yeah, that's kind of fun. The universe is not, the universe is like a sponge where if you take a cut through it, you'll see voids where there's no sponge and then on the edges of the sponge, edges of the void, you'll see the sponge material. And that's what the galaxies look like when you take slices through them in spacetime.

• 21:20Chris Williamson?

  It's interesting though, because the universe is supposed to be relatively homogenous, right? Isn't that one of the things that's predicted?

• 21:27Speaker 00

  Well, it was, it's statistically homogenous above a certain scale. It's obviously not homogenous in your, the room that you're standing in because you're in one place and there's air in another place. So if it was homogenous, your molecules would be equally spread in the room that you're located. So you have to say, on what scale is it homogenous? And

• 21:49Speaker 00

  If you back up enough and you see enough contents, you could say now I have a certain mixture of galaxies in this volume. I look over here and I see approximately the same mixture over here and up there. So then you know what counts as the, you know, it counts as the, that is representative of what the universe looks like.

• 22:14Chris Williamson?

  The scale at which we can start to draw some conclusions about what it's going to be. Yeah, it's, I mean, if it's not 300 million light years, though, you think that that was what inferred to me, oh, well, maybe the observable universe is only a really small part of a much bigger universe, because within this, you don't have a massive amount of homogeneity.

• 22:32Speaker 00

  Right, right. So but a big enough volume, you do. So that's how you get out of that.

• 22:38Chris Williamson?

  Just scale out a little bit more.

• 22:39Speaker 00

  Right, correct.

• 22:41Chris Williamson?

  If the big bang was when time began, when's time going to stop?

• 22:47Speaker 00

  So there's no evidence that it would stop. Well, it would stop at the big rip, for sure. But if we don't have the big rip, where the universe is expanding so fast, that it rips the very fabric of the universe, that, if that does not happen, then we'll just expand forever. And so time just continues forever.

• 23:12Chris Williamson?

  Would the big freeze not eventually end up with everything decaying on a long enough time scale to the point where time kind of becomes irrelevant?

• 23:21Speaker 00

  Yeah, oh, no, that's a different question. Right. So if I keep winding a watch, the watch will keep time. But there's a point where, what energy am I using to wind the watch while I'm eating some food, where that gets integrated from the sun, the sun is gone, then there's no energy and I can't wind the watch. And so there is a limit to this. And the, but otherwise, the time just slows, the

• 23:49Speaker 00

  There's nothing left for you to care about timing.

• 23:53Speaker 00

  That's really how to think about it. There's nothing there. You know, how long did you run that race? There's nobody running a race. How long did you boil the egg? There are no eggs, right? So I guess we can call that a practical end of time. There's nothing left to measure time with. But otherwise, it would just continue forever.

• 24:12Chris Williamson?

  Yeah, interesting. I learned as well, the same day that I learned about the Buete's super void, about the reason or a question about why the plank length exists. Why is it that there's a smallest measurement at all? Is there a reason for that?

• 24:31Speaker 00

  Um, well, so it depends what you mean by reason.

• 24:34Chris Williamson?

  Well, why can't anything be smaller than it?

• 24:37Speaker 00

  Because that is the very structure that comprises everything that's bigger than it. So now there's a

• 24:51Speaker 00

  there's a movement, a cottage industry, I should say, that

• 24:57Speaker 00

  is wondering whether the plank length, this smallest unit, consider it like a voxel, a volume pixel, right? This plank length is fundamental or is there something more fundamental than that? There's emergent research to suggest that space and time emerge from other forces operating.

• 25:21Speaker 00

  And that's, that's an interesting fact. So if that's the case, maybe you can get something smaller than a plank length, but not by any known means that gives us an understanding in the first place.

• 25:34Chris Williamson?

  There's an equivalent in time as well, isn't there?

• 25:36Speaker 00

  Yes, yeah, so the plank length in time is how long it takes light to cross a plank length.

• 25:44Chris Williamson?

  Oh, no way.

• 25:45Speaker 00

  Yeah, yeah, so that's a, so that's a unit of time. And that makes a cube in spacetime.

• 25:53Chris Williamson?

  That is interesting. The coolest explanation that I heard for it was that the plank length is the pixel size of the simulation that we're living in.

• 26:02Speaker 00

  Yeah, that's another way to put it. That's right. But when you get to the big rip, who knows what that will look like? We have no idea. And by the way, yeah, if we are a simulation and you want to think a bit of it that way, there's nothing stopping you from saying these are the pixels of our simulation.

• 26:20Chris Williamson?

  Is it right that the speed that light goes at is the maximum speed that anything can go at? Is that determined by the fact that it's light? Or is that a maximum speed limit? And it happens to be that light travels at it?

• 26:35Speaker 00

  We don't know, but both are true. Both are true. And by the way, when light slows down, light slows down is when it enters transparent media that are more dense than air. The, um, so when it slows down, it actually hasn't slowed down. It's moving at the speed of light between the molecules, but then it has to pass through a molecule and that slows down the total duration.

• 27:05Chris Williamson?

  It's got to go a further distance as it weaves through.

• 27:07Speaker 00

  So I don't know if it's quite just further distance or if it's the interaction that it has with the molecules of the substance. I wouldn't think it's a further distance because that would imply something different.

• 27:25Chris Williamson?

  Bending somehow, yeah.

• 27:26Speaker 00

  Yeah, yeah. And I don't think it's distance dependent. But in any case, this, this,

• 27:34Speaker 00

  so the speed of light is still going at the speed of light even when it's moving slower. That's my point.

• 27:38Chris Williamson?

  Which makes complete sense, obviously.

• 27:40Speaker 00

  Right, right, right, right.

• 27:42Chris Williamson?

  Yeah, I just found that really interesting. You wonder whether the maximum speed that things can go at is the speed of light, or if there is a maximum speed that things can go at and light happens to travel at that speed. I thought that was an interesting distinction.

• 27:55Speaker 00

  Well, except material items can't travel at the speed of light. So, so.

• 28:02Speaker 00

  I'm recording. So you have my image here. And if, sorry, if I wanted to join you, I can't. I can travel 99.99999% speed up, but I can't travel the speed of light. It's, it's, it's forbidden, all the equations forbidden. And we've never seen it happen.

• 28:26Chris Williamson?

  Yeah, well, I don't know. The, the insights around how future civilizations can perhaps travel, whether or not we can wormhole tunnel our way across the galaxy and stuff like that. That kind of goes back to what we were talking about earlier on with the intelligent life. It's not a surprise when you see just how spread out things are. You know, it's only a presumption based on how likely it is that some life has occurred within our galaxy. But if the universe is as big as we thought it is, and we don't have another example of life evolving, it's pretty difficult to work out whether or not we should actually be seeing aliens at all. I can't remember what the letter is in the Fermi paradox.

• 29:08Chris Williamson?

  But there's one, what is it? What's the typical equation that goes along with the Fermi paradox?

• 29:16Speaker 00

  No, don't confuse it with the, the Drake equation.

• 29:19Chris Williamson?

  That's it. Thank you.

• 29:20Speaker 00

  Right. Oh, you did. Okay.

• 29:22Chris Williamson?

  That's.

• 29:23Speaker 00

  The Drake equation, you know, you start out with the total number of stars in the galaxy. You start hacking away at it with fractions. What fraction of those stars have a planet? What fraction of the stars with planet have life? What fraction of stars, no, what fraction of stars with planets are in the Goldilocks zone? And what fraction of those in the Goldilocks zone have life? What fraction of those in the Goldilocks zone with life have intelligent life? What fraction of those in the Goldilocks zone that have life and have intelligent life? Have intelligent life with technology that can actually communicate? And that enables you to remove the Roman Empire from this. Because like I said, they wouldn't have known how to answer back. If someone tried to talk to them.

• 30:04Chris Williamson?

  Where is the biggest hole in the Drake equation for you? Or what's the biggest question mark over?

• 30:09Speaker 00

  Right now, it's the, for me, it's what is the anticipated length that a civilization is capable of communicating?

• 30:19Speaker 00

  And that, because that one doesn't rely on pure astrophysics. There's a social-cultural dimension to that. And I, I can't bring my methods and tools of science to address that. Is are we wise enough to be good shepherds of the power that we wield such that seven generations from now they'll be proud of us as their ancestors for having preserved the earth? I don't know that I, that's, that's how, that's how it should be. Okay? But it's not that, of course.

• 31:01Chris Williamson?

  Outside of your scope, a little bit.

• 31:02Speaker 00

  Right.

• 31:03Chris Williamson?

  Do you think that our descendants will leave the Milky Way eventually?

• 31:08Speaker 00

  No.

• 31:09Chris Williamson?

  You don't think so?

• 31:10Speaker 00

  No. Nothing we can't, there's just no reason to. I think as the sun gets hot and bulbous, we might want to move out to Mars. And that will matter and because Mars is farther away, so we get to delay the inevitable demise of our civilization by knowing this well in advance and taking precautions to accommodate it. But otherwise, you know, I, you know, I'm good with Earth, just as we have it.

• 31:53Chris Williamson?

  That's got a limited time span on, on it though, right?

• 31:57Speaker 00

  What, what, what, what, what are you timing out on us?

• 31:59Chris Williamson?

  Well, whether it be the sun boiling off the oceans.

• 32:03Speaker 00

  Oh, yeah, yeah, yeah, yeah. Yeah. So we have, we have to assume that we as a mammal species outlive a typical mammal species that goes three million years. We have to somehow make it clear that we want to give, we want to live beyond Earth itself and even beyond the sun. Right? So first you're going to planet hop your way away from the sun, but then you have to find another star. By the way, something not talked about, when the sun exhausts its hydrogen in its core as a big ball of helium.

• 32:43Speaker 00

  The sun dies, the sun will die because it can't convert helium into carbon. Okay, that's fine. So how about all the rest of the star? It turns out if you find a way to cycle material from the outer star to the inner star, if you can do that, then you will prolong the life of the star ten to a hundred times. Because it only burns out when it's no longer hydrogen in its core. But the fresh hydrogen in the rest of the star and you constantly funnel it down. Uh, you've got, you've got exactly what you need.

• 33:20Chris Williamson?

  Was that, was it Sunshine? Was that the film? Where they send a mission to drop, I think they drop a nuke actually into the, the heart of the star in an effort to try and get it back, but.

• 33:32Speaker 00

  But that was the, that was the science fiction movie.

• 33:34Chris Williamson?

  I'm aware, I'm aware. Yes. Yeah, I'm getting, I'm, I'm, I'm trying to bring this back to the real world. So my point is just that that was talking about somehow impacting the natural flow of the sun. And what you're saying here is that if there was a way to funnel that back in, it wouldn't be a nuke, but if there was a way to do it.

• 33:51Speaker 00

  Correct. You just, you just, you just give it a new lease on life. In fact, there are these stars called blue stragglers, that's what we call them, that should have evolved into a different state at the time we noticed them, but they haven't. And all evidence points that it's two stars that have collided and have become one star. And the act of colliding re-churned up the fuel supply and it has given it a new lease on life. So these are stars that are lingering behind the evolution of a, of a star cluster. And we have no other explanation for them, but that their innards got churned up.

• 34:26Chris Williamson?

  That's pretty cool.

• 34:27Speaker 00

  Blue stragglers.

• 34:28Chris Williamson?

  So we need to find, we need to find another star fired at R1.

• 34:31Speaker 00

  That would, that would, that would be short of reaching in with a ladle and doing it ourselves. A collision would surely make that happen. Yes.

• 34:40Chris Williamson?

  Yeah, like you're cooking soup. That would be one solution. Yeah, it's, um, one of the things I was thinking about, I think that a couple of the guys at the Future of Humanities Institute are looking at. Solar forming, so how you would, if you wanted to create a solar system and move stuff out of the way that you didn't need there, they're talking about some of that at the moment, and I think that kind of probably ties in at least a little bit with how you would potentially be able to move a star around, or at least the material inside of it.

• 35:11Speaker 00

  Well, so I'm not sure what their objective is. We're in a solar system now that has eight planets, and they're not bothering us. I don't know why you'd want to move it around. I can tell you that modern models of the formation of planets show that you can start a solar system with upwards of 30 planets, and not all orbits will be stable. If they're not stable, they'll fall into the sun, fall into Jupiter, or get ejected from the solar system altogether. And so, this is a, so maybe they're saying, if you want to hurry up the evolution of a solar system, you say, okay, let's get rid of these,

• 35:55Speaker 00

  and add those, and subtract those, move this into the right spot, so that you have the Goldilocks effect. That's not just geoengineering, that's star system engineering, that, you know, I don't foresee that anytime soon.

• 36:11Chris Williamson?

  Is that the best way, if you wanted to design a solar system, to overshoot on the number of planets that you would need, and then sort of allow the orbits to sort themselves out?

• 36:22Speaker 00

  Well, you don't need the extra planets, so just stick a nice sized planet in the Goldilocks zone. It's a one planet solar system. It'll be stable. The instability comes when you have a lot of objects tugging on each other for every orbital period. But you throw one, maybe throw in a Saturn just to be beautiful at night.

• 36:40Chris Williamson?

  Just cool, like when you're landscaping your garden.

• 36:43Speaker 00

  Something to do.

• 36:44Chris Williamson?

  Yes, yeah, I understand. Yeah, I mean, to see a single planet solar system would be pretty cool.

• 36:55Speaker 00

  Yeah, and then you could say the sun is all ours. It's you can't.

• 36:59Chris Williamson?

  Even you Mars with no one on it. But isn't it that most solar systems or the vast majority of suns are twin suns rather than?

• 37:07Speaker 00

  Yeah, so I think that the proper way to say that is more than half the stars in the night sky, when investigated more closely, reveal that they're in pairs, triples, or just multiple stars in a system. Right, so the single star star system is is not as common as you might think.

• 37:27Chris Williamson?

  Why do you think that is just the way that gravity works?

• 37:29Speaker 00

  No, no, just planets go unstable. It's just, oh, sorry, sorry. I'm sorry. So I mixed two answers. If you have multiple star systems, you don't expect them to have many planets because planets will not fully track their gravitational allegiance and they can get ejected very easily.

• 37:50Chris Williamson?

  Oh, it's a less stable gravitational environment.

• 37:52Speaker 00

  Stable. And in fact, in the famous Star Wars scene where Luke is on the sand planet and he comes out and he looks, there's a double sunset. All right. Very important and poignant moment in the film containing the only accurate astrophysics in the film, by the way. So that's a planet orbiting a double star system. We've always known that could happen. They showed it, but they did it right because it is possible to orbit two and multiple planets. If your orbit is far away compared to the distance among the stars to each other, then the orbit thinks it's just one source of gravity. But if the stars themselves are orbiting at great distances from each other and you

• 38:34Speaker 00

  are now weaving in and out and among them, that's a recipe for disaster.

• 38:39Chris Williamson?

  Welcome to the Universe in 3D, which is the new book that you've got out. What's going on with that? What's what was the the inspiration behind that?

• 38:46Speaker 00

  Oh, yeah. So that's actually the fourth in a series of Welcome to the Universe books. The first was a textbook, basically, that I co wrote with two colleagues of mine when we co taught a class introductory astrophysics class at Princeton University. The class went from like 40 people to 300. And so it was very popular very quickly. We had to change rooms twice and we're delighted by that, but we think we know why it was popular. It was taught in a very breezy way, very anecdotally. And all the three of us were pretty well connected to all manner of things. And so it was was just so in that sense, it doesn't smell like a textbook, even though it looks like one. And but some people said, we want to use it as a textbook for our class. So

• 39:31Speaker 00

  we said, OK, cool. So then we wrote a problem book to go with it because that enables you to assign problems. Then people said, this book is too big. I want to learn what's in it, but in a short format. So then we created Welcome to the Universe, the Pocket Size Tour, that literally fits in your pocket. And then we said, well, the universe is something to look at and to embrace. So if we take selected handpicked images, double them up in a stereo book, and have a viewer, then these images become worlds. They become real. They become something you would interact with emotionally, not just intellectually. So that's what that's what Welcome to the Universe in 3D is is 66 images, and it's

• 40:16Speaker 00

  a uniquely designed jacket binding so that it unfolds and you have the built in viewer. But the it doesn't end there. There's a website, WelcomeToTheUniverse.net, where all four books are featured. But you go to the 3D book, and as a bonus feature, I've narrated the captions to each image pair. And I use my planetary voice. Yes. Welcome to the universe. All right. So yeah, I'm a direct planetary director. So I got to have that

• 40:55Speaker 00

  voice, right? So so that way you can participate in the book while you're being read the captions, rather than move back and forth and read them. So this is a little little after hours bonus that just in the it was like 10 days before the book release, you said, why don't we do this? OK, yeah, but I'm the one that has to do it. So everybody voted.

• 41:17Chris Williamson?

  Why don't you do this?

• 41:19Speaker 00

  I was totally outvoted. And so I ended up doing it. So.

• 41:23Chris Williamson?

  Neil deGrasse Tyson, ladies and gentlemen, what have you got coming up next? Is there anything that people should keep their eyes out for?

• 41:29Speaker 00

  Oh, thanks for asking. I just finished another book.

• 41:34Speaker 00

  It was a covid book. I said, you know, I could binge more, you know, Rick and Morty, or I can write a book. So I chose to write a book on a book that was gurgling within me. It's a book I could not have written even five years ago. It is called Starry Messenger, Cosmic Perspectives on Civilization.

• 42:02Speaker 00

  And it is me taking a look at all that divide us, all that divides us, and saying, here's what that looks like from space, or here's how an alien would think about it, or here's what that that argument you've just made, here's what that looks like when you add a little bit of science to it, all right, science literacy. And what you'll find is that in most cases, the depth of your argument just dissolves away. And you end up, and I'm not talking about a compromised position in the middle, I'm talking about a whole new place that neither of you saw, because you're not thinking about it scientifically or cosmically. And so there are chapters, there's a chapter in there on gender and

• 42:46Speaker 00

  identity, on color and race, on truth and beauty, on life and death, on on meatarians and vegetarians. There's an, there's a eternal conflict for you. And there's risk and reward, these things that have chow, that prevent us from all holding hands and singing kumbaya. That might still be possible if you take another look at your argument. And that's what this book does.

• 43:18Chris Williamson?

  Why couldn't you have written it five years ago?

• 43:20Speaker 00

  I wasn't wise enough. I didn't have enough, because it's, it's not just, let me throw down some science, I could do that at any time. It's, here's a nuanced way the science influences this subtle argument you think you're making, that you think is the end all argument. I've had, I needed enough exposure to that. Enough encounters with people to hear how they think about problems. So that when I come back at them, I can maximize the bandwidth of how I communicate with them. So yes, it's a book of maturity, dare I say.

• 43:58Chris Williamson?

  When are you planning to get that out?

• 44:00Speaker 00

  Oh, it's already, it's in press right now, so September. Which is not even that far from that, like May, June, July, August, you know, it's four, four and a half months. Um, and so it'll, it'll have, it's, by the way, it's, you can preorder it, I think on Amazon right now, actually. But it's a, it's a crazy, it's. Uh, I would, I would have been irresponsible. Given what I know about this world and about science and about the universe. If I did not offer this book to the public, I'd be irresponsible.

• 44:38Speaker 00

  And, uh, you know, the little things, observations, for example, uh, you didn't ask, but I'll just tell you. Um, in the risk and reward chapter, it's all about how ill-equipped we are to evaluate probability and statistics. We are so bad at probability and statistics, entire industries exist to exploit how bad we are. They're called casinos, they're called lotteries, okay? If we taught probability and statistics in school, early in school. With same ranking as reading, writing and arithmetic, okay, reading, writing, arithmetic and probability, okay? It's statistics, add it to that list.

• 45:20Speaker 00

  If we did that, no one would play the lottery. Oh, here's something interesting, in order to make you always allow the lottery. They use lottery revenue to pay for education. So if that money that went to education went to teaching people probability and statistics.

• 45:40Speaker 00

  You couldn't hold the lottery because all that extra education money would go away, right? Because no one would play the lottery that's feeding you. So it is in the lottery's interest to not teach you probability and statistics. There's interesting little facts about this that run throughout society and all those topics that I mentioned. There's a whole discussion in there on the removal of statues, you know? Have you thought about that scientifically? What that means? What are the arguments? What is the weight of the argument? Or are you reacting sort of emotionally to it? I don't mind emotions, but emotion without some kind of foundation in rational thought, then society becomes

• 46:23Speaker 00

  a free-for-all. And there's no objective foundation on which to base anything. Not the least of which are laws, which should be based on objective truths. Oh, by the way, there's an entire section in there on law and order. Okay? And what does it mean that a jury has arrived at a verdict? Based on what? On a testimony? Is that testimony from a human being that used their own senses to evaluate what is and is not true about this world? Really? You're gonna put someone in prison based on a human being's testimony?

• 47:03Speaker 00

  Holy shit! Okay? You know, in science, if you came to a conference, "This is true because I saw it"? It's get the hell out of here, okay? Our brain only barely works as an organ, okay? Barely works. You can look at one of those books with the images that fool you, Optical Illusions. Go pick up any Optical Illusion book. There's a line, and is the line longer or shorter than the other line? I don't know. Is it a vase or is it a face? These are simple line drawings that completely confound us.

• 47:47Speaker 00

  And we're gonna send people to hang? Or to whatever, they kill them in fifteen states? Because you have a testimony that implicates them? Oh my gosh, so I'm bringing scientific rationality to these issues? That's all it is, that's what that book is about. And it's a whole other thing, unlike anything I've ever written. I birthed the book during Covid, because I'm alone. And it was gurgling up in me. And the baby had to get born. And it got born, and that's what happened.

• 48:18Chris Williamson?

  And now you're stepping into the culture wars.

• 48:21Speaker 00

  Well, except I'm not telling you how to, how to think or feel. I'm arming you to become a better thinker. When it's time for you to feel about what it is you want to pass judgment on.

• 48:33Chris Williamson?

  And what's that book called again?

• 48:36Speaker 00

  Starry Messenger: Cosmic Perspectives on Civilization.

• 48:42Chris Williamson?

  Neil deGrasse Tyson, ladies and gentlemen. Neil, I appreciate you. Thanks.

• 48:45Speaker 00

  Thanks for having me. Thank you.

• 48:47Speaker 02

  Mr. President, my company told me of the explosion on our rig.

• 48:51Speaker 03

  On October 2nd.

• 48:52Speaker 02

  Causing massive water displacement and triggering a tsunami. They all heap the blame on me.

• 48:57Speaker 03

  Tom Cruise is. Digger got us into this mess. And Digger's gonna dig us up. From the director of Birdman and The Revenant.

• 49:04Speaker 04

  What would happen if I stopped drilling? You're stalled, you freeze to death, that's what.

• 49:08Speaker 03

  With great power comes great deniability.

• 49:11Speaker 04

  I'm not the first then.

• 49:13Speaker 03

  Digger. See the trailer online. Only in theaters October 2nd. Rated R. Under seventeen. Not admitted without parent.