Sean Carroll's Mindscape: Science, Society, Philosophy, Culture, Arts, and Ideas - 210 | Randall Munroe on Imagining What If...?

Episode Date: September 12, 2022

What's the fastest way to get a human being around a racetrack, if we ignore all the rules of racing? How many pages would you have to read to absorb all of the government laws that apply to you? It's hard to imagine a better person to tackle these kinds of slightly-askew questions than Randall Munroe, creator of the xkcd webcomic. He collected some answers in his book What If?, and has released a sequel, What If? 2. We dive into how one goes about choosing the right questions and answering them, and how to make it funny along the way. Support Mindscape on Patreon. Randall Munroe received a degree in physics from Christopher Newport University, before working for a while at NASA's Langley Research Center. He is now the creator of xkcd and the author of several books. What If? and What If? 2 are based on a regular feature in which he tackles questions asked by readers. Web site Amazon author page Explain xkcd Wikipedia Twitter

Hello, everyone, and welcome to the Mindscape Podcast. I'm your host, Sean Carroll. In certain corners of the internet, certainly ones that I find myself in all the time, there's a saying that goes, there's an XKCD for everything. XKCD, of course, is the wildly popular web comic, started in 2005 by today's guest, Randall Monroe. And XKCD is famous for many things. It has a very austere minimalist art style featuring more or less stick figures, doing things, very often just talking to each other, but there's also a spirit about it that is very, very resonant with people who care about science and technology and building things in numbers and lists and words, but also who understand that these things are connected to humanity and love and

emotions and things like that. It's also remarkably good at finding those little things that you've been thinking about and turning them into webcomic form, thus the idea that there really is an XKCD out there for everything. One of the very popular features of the blog that Randall runs, associated with SKCD, is the what-if section, where he started a few years ago taking questions from readers about, you know, what if this crazy hypothetical scenario was going on, something that he himself is very fond of doing. This is the origin of probably many of the comics.

And the great thing about the what-if questions is that it's not just a yes or no answer, and you have to really think sometimes, you know, the questions being asked. The famous, the iconic what-if question is, what if someone pitched a baseball at 99.999% the speed of light, what would it do when you tried to hit it? You have to take that seriously, right? You know, okay, what would it mean to move at that speed through the atmosphere? And you have to ignore the problems, like you cannot throw a baseball that fast, and take seriously the consequences. And what Randall has subsequently done is to collect some of the best answers to the what-if questions into a book, first called What-if, serious scientific answers to absurd hypothetical questions, and now just very recently, What-if-2?

Additional serious scientific answers to absurd hypothetical questions. And what I love about the book is that you really learn a lot by reading it, not just because he gives you the answers, but because he walks you through the methodology for answering these questions. and of course it's sprinkled with humor and cute little cartoons along the way. Randall really has an amazing capacity to think about things in a new and enlightening, illuminating way. And so it's been great to talk to him. We're going to talk a little bit about some crazy hypothetical questions and a little bit about the general strategy for addressing such questions and why it's so interesting to do so.

So let's go. Randall Monroe, welcome to the Mindscape Podcast. Thanks. It's so great to be here. So you have a famous comic strip, obviously, famous web comic, but the immediate reason that I was able to get you on the show here is because you have a new book coming out. So I do want to talk about the book because the more I think about it, it's just a kind of a fascinating concept and you're clearly having a lot of fun with it. So why don't you tell the audience about what if and its successor, what if two, and why this is a good thing to do and buy a book about? Well, I originally started off drawing comics about science, and because I touched on these subjects of weird science ideas, I found people would often write to me with questions to answer,

which I was not expecting. And often, it wouldn't just be that they had their question. They thought I was the best person to answer it. There was sort of an undertone of like, it was like a backhanded compliment. They were like, me and my friend have been arguing over this science question, but we don't think it's a good enough question, like important enough question to bother a real scientist with. We all agreed you seemed like a good person to talk to. He had nothing else to do. Yeah, he probably, that guy who does the comics, he, he's not a real scientist. We can bother him. And so I, but the thing is, they were right. I, I, I, so I would spend, you know, I would get an email with some question about Superman or, you know,

building tall skyscrapers or dropping things off of other things or lava. And I would see the question. And it's like, you know, one of those things where you briefly black out in like six hours have passed. And I would have like, you know, 500 tabs open and like 80 PDFs and like books that I dug out of the closet. And because I'm just determined to know like, all right, once I've seen the question, I want to know the answer.

Yeah. And so I would send them all this work I had done. And at some point, I was like, I'm putting a lot of work into these emails, which are probably half of them getting spam filtered. Like, I should share some of this research because I'm learning all this cool stuff. And so I started posting them online and eventually publishing them as a book. First, what if? And then the problem with publishing those is it only leads to more questions. Of course.

Just asking for it now. And so then, and so now what if, too? And it's like my compiled answers to these questions that random people have sent me. So to give the audience who unfortunately has not read what if one a flavor for what's going on here, just tell us one or two of your favorite questions that you've answered. Well, I mean, the one that I, the one that I, that it sort of all started with was what would happen if you tried to hit a baseball that was pitched at 90% of the speed of light. and it's fun because I like questions where you're like,

well, right away, I know nothing good is going to happen there. It's not good, right. But I'm not actually sure what would happen. And that was the case. You know, I ended up having to spend, you know, six hours just going through sort of the particle physics of like the ball would start crashing into the air in front of it and, you know, might undergo nuclear fusion. how many of the air molecules would pass directly through the ball,

how many would fuse, what would they release? And you end up with this sort of millisecond or nanosecond by nanosecond picture of like the ball disintegrating into an expanding cloud of radiation and destroying the playing field. Presumably, yeah, the kinetic energy is large enough that the explosion is going to be pretty big. Or is it mostly from, because there's no antimatter as running into, there wouldn't be a lot of conversion into actual pure energy. It's just the kinetic energy, right?

Yeah, well, it's the kinetic energy. You do get quite a bit from fusion, though. For fusion, okay. Because the ball is going fast, and it's actually going fast enough. I got some folks from an MIT high energy laboratory after I published the first book, who said, you know, hey, we saw your question, and we love this. So we ran the simulation of those impacts. And here's how the actual energy distribution worked out, which was cool.

I got the software, and I got to run it myself. but it's fun because like it's fun to get specific. My favorite thing about that scenario is that the ball is approaching the batter, but it's moving it near the speed of light, which means the batter doesn't have any sign that it's coming until the first wave of radiation hits. And once it does, the speed at which signals move down the optic nerve is slower than the rate at which the actual cloud of the ball approaches and starts disintegrating you. So you would literally not see what hit you. It's interesting to me because there's a lot of steps in the thought process at which many people might say, well, no, this is just not going to happen. So I'm not going to follow it up.

Like, I could say, no, you can't throw a ball at the point line of the speed of light, or, you know, what would happen is it would go by the person so quickly. But taking into account exactly the right level of detail seems to be part of the art form here, right? Like, just say it's going 0.9% of the speed of light, but don't ignore air resistance, right? These are very explicit choices along the way. Yeah, yeah. And the way I usually think about these is, like, we're not going to worry about how the situation got set up. exactly like we're the the the the premise is what if like what if somehow this situation occurred and then you like press play on it and let normal physics take over um and so often people would

would kind of design questions trying to elicit really destructive uh results you know you'll so so i found that people who liked the questions in the first book you know would send in things like, well, what if I put a nuclear bomb on a train that was going at relativistic speeds, but through a tunnel so that it doesn't interact with the air, and then it's going toward a volcano or something. And this is where I found that, like, little kids asked some of the best questions because little kids aren't trying to come up with something weird. They're just, like, asking an actual question that they're curious about. Right. And that was, like, one of my favorite ones in what if too is a little girl who asked,

what if I wanted a billion story building? And she, like, asked her dad, and he couldn't answer it, so he sent it to me. He was like, you know, I don't really know what gets in your way if you do that. And what's funny is it's like it's a much more concrete question. It's like a straightforward real question. And the answer turns out to actually be more destructive than the train thing. Oh, really? Well, go ahead.

Tell us the answer. Don't hold us in distance. Well, like, a billion stories is, you know, really, really, really tall. The upper limit on skyscrapers isn't really engineering. It's more money. You can build a skyscraper up into the, at least, you know, much further up into the atmosphere than we've successfully built them. It just gets rapidly more expensive, and there's just not a lot of economic incentive to do that. Most of the really tall skyscrapers are sort of built for bragging rights as much as anything.

But a billion stories is just orders of magnitude bigger than that. And so you'd end up with a skyscraper that is far enough out that as the Earth is rotating, it's being flung outward by centrifugal force harder than gravity is pulling it down. So you end up with a sort of space elevator situation where suddenly your problem is not making it strong against compression. It's keeping it from being flung apart. And you would also, with a billion stories, that's enough that you would have a problem where the end of the skyscraper would be in danger of swatting against the moon. Not the sun, but the moon. So you'd end up with these fragments of skyscraper falling.

And even if it's not that big a building, the amount of energy in, you know, a billion, you know, half a billion floors of us building entering the atmosphere all at once. You're going to get some pretty significant destruction here on Earth when the thing finally falls apart. So clearly one of the skills you have to develop, or maybe you just had this all along, is the research aspect of this, right? You're not sitting down with pencil and paper. I mean, when you say things like the limitation on skyscrapers is more money than engineering, how do you find that out?

I mean, do you have secrets, or is it just like fire up to Google like everybody else? I think at some point, a useful skill in this kind of thing is being able to skim a lot of different things until you find something that's promising and then dig into it. And usually what I'll do is either, you know, skim until I, like, just look through Google libraries. Like the Internet Archive has a lot of cool, weird old reports on it. But really some of the best resources are just PDFs on some, like,

defunct government website where the link is broken, but you can find an archive copy. And it was like, oh, this was briefly posted in 2004. And it happens to be like a report on someone in the 60s who did this exact thing. I really do like the very practical questions that don't even like one of the ones that didn't really require all that much in the way of fancy physics was someone who asked, she wanted to know what would happen if she walked over the, stood over the geyser at Old Faithful in Yellowstone when it erupted. Sure. And that's a great question. And it has my favorite quality, which is like, I hear it.

And I'm like, oh, well, I mean, of course you, I mean, nothing good, but like, would you get flung into the air? Or would it just burn you or what? And so, like, one of the first things I did, you know, I did some back of the envelope calculations about, like, how much liquid actually comes out of there? In what form is it? You know, what's the flow rate? What's the speed? What's everything? But also, like, has anyone done that?

And so I was looking at like records of, you know, injuries around Old Faithful. The park service is very clear about how you should not try to do this. And what I learned sort of surprisingly was as far as it, so I found this wonderful book, Death in Yellowstone by the Yellowstone Park historian that just kind of catalogs all the different natural hazards there, of which there are a lot. you know, everything from like exposure to rock slides to falls to lightning, quite a bit of that. You know, people who try to feed bears or take pictures with them. Bison, surprisingly dangerous. And also some regular human murderers. They've got a few of those there, you know, like many places. But what was interesting going, and so when I'm like looking through research, part of it is try to find something that has the answer.

And this book did indeed have the answer, which is that, Surprisingly, no one has, as far as I can tell, been killed by the geyser itself erupting. But it's also, you find a book cataloging all of the different injuries that happen to people in Yellowstone. And that's going to, like, even if I don't see the answer I'm looking for there, I'm like, wait, okay, I want to stop and read this, you know, like the chapter indices or like all these different kinds of injuries. And some of them are things that never even occurred to me. And so what I learned is not a lot of people have been killed there. A huge number of people have been badly burned, many of them by leaning over and trying to look into the geyser when it erupts. When it erupts.

It's like exactly the thing you'd think. There's even, I think there was a German doctor, a tourist who fell in in the 1920s, who fell into the little crevice where it erupts. and managed to get out as it was erupting and was scalded but survived. So is that because the water is hot? I don't know much about old people. Yeah. So the geysers, they're erupting water that's really superheated. It's under extreme pressure.

It's coming out going, you know, on the order of, you know, 50 to 100 meters per second, I think. The amount of momentum carried by the stream, it has pretty low density. It's like, you know, one of those cotton. handy type, a fluffy pillow. But it's like getting hit by a pillow going at, you know, the speed of a car on the highway. Right. If you took a direct hit from the stream or if you stood over it with an umbrella or something, it could absolutely fling you very high into the air. Okay.

So probably the fall would get you before the burns if that happened. But people do get very badly burned, including, so the reason that they tell you not to do this is that they tell you not to go near the geyser. is that it is extremely dangerous, of course, to get scalded by the geyser. But what the real danger there is, around the geyser, there are all these boiling mineral pools that are of, you know, like just barely on the edge of boiling water with a mineral crust over the surface. And so if you, like, are walking around there,

you could step on what looks like rock and just plunge through into boiling water. Wow, okay. Good safety tip. there are some very harrowing accounts of accidents that are kind of that I at some point I'm like, all right, I've read enough of these. I don't want to. But, you know, so, so really what we get you would be trying to walk toward the geyser. That's where the real danger is. And so my big takeaway from reading this is like, if you ever go to Yellowstone, they've got railings, just stay behind the railings. That is good advice. It's there for a reason. There's a whole book cataloging why. This podcast is sponsored by Talkspace. May is Mental Health Awareness Month. In Talk

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I mean, I'm a theoretical physicist by think about where the universe came from and how quantum mechanics works. And the whole art form there is simplifying away all the complications. And almost every question that you answer in the book is about, there's this complication you didn't think about. and that changes what you might have guessed. Yeah, and I think it's sort of an interesting question, because when we talk about simplifying away the complications, we're doing it in the service of answering a question, you know? Like, the reason you assume a spherical cow in a vacuum,

as the physicist expression goes, they never say, what is it you're trying to find out about the cow, you know? Like, you're doing this in the process of trying to figure out, what would the cow's orbital path be? Or, you know, how much would its mass increase if you did this to it? Places where the vacuum and the shape don't matter. But, like, you do have a question you're trying to answer. And so a lot of the what-if questions, the question is just kind of broadly what would happen.

Sometimes it's like, would this work? Would you be able to do this? But in every case, you know, the simplifications you're making are guided by, like, that question you're trying to answer. You know, so I feel like you're, you're doing the same process, I think. You know, the, like, when you, when you're, I don't know, when you're, when you're building an inflationary model of the early universe, like, you could just simplify away everything, right? You could just be like, well, at this time, there was the universe. We won't worry about the details.

But you don't. I think, I think you're, you're, you're selling yourself short by saying you don't address the complications. It's all complications. Just choosing which ones you're going to focus on. I mean, I guess the everyday world, you know, dinosaurs and baseball and geysers to the extent that they're the everyday world, this is deep within a regime where

the dynamics are complex and nonlinear and strongly coupled to each other. And it becomes hard to, you know, figure out exactly what matters and what doesn't. Like, have you ever answered a question and then had some expert come along and say, like, no, no, no, you miss the most important thing?

I would say I have been lucky to mostly avoid that level of having someone say, oh, you've got this all wrong. I also will often tackle things where I'm like, well, I'm pretty sure no one's going to be able to test this. So who's to say whether I'm wrong about what would happen if you threw a battleship into the sun or whatever it is? but you know and I and I really I think I have an instinct to hedge on things I like I really I'm not I'm not just trying to give a good answer you know I'm trying to find an answer that satisfies me and so so there are a lot of things where it's like well I don't know what would happen here's a reasonable guess here's why you know and I'll try to be be you know up front about that when I'm when I'm really not sure about something it is fun when I have a question that I don't think is going to be easy to test,

and then someone comes along and tests it. In my first what-if book I had, someone had asked about if you threw a stake into the Earth's atmosphere from up very high up when it fell in at hypersonic speed, how high should you drop it if you wanted to be perfectly cooked when it lands? And I did a bunch of theoretical calculations about, But I, so at first I came into this as, you know, I have an undergraduate physics degree. And so my instinct was, okay, I know about stagnation temperatures, meaning if you have something

flying through the air, it compresses the air in front of it, and the center point reaches a certain temperature. And you can figure out what's the temperature of the stake going to be at different points in its descent. And then I start looking up, okay, how quickly does heat propagate through meat like, you know, these materials, like a steak or water? or, you know, how do you approximate it? And, like, if you apply this much heat at this temperature, you know, how much will the back

of the steak heat up? How much will the sender heat up? And I was really struggling to find good articles on heat propagation through flesh, you know, through. And then at some point, I had a moment where I sat back and I was like, wait a minute. And then I, like, close all the physics tabs and just open a cookbook. Yeah, I was going to say, there are people who are devoted to this. Like, oh, wait, there's a different regime, a different domain of expertise where they

know a lot about what happens if you apply different amounts of heat to a steak. And then it turned out it was very easy to answer. And the answer is that your steak would be a style called Pittsburgh Rare, where it has like a seared very edge, but the inside is still like raw. But what was interesting, so I put up my explanation. You know, I said, okay, the steak is going to probably tumble. And I don't know how a steak would tumble in hypersonic winds. You know, there are some shape where there's there are models for this, but sort of large, kind of floppy piece of meat that's roughly the size and shape of a steak,

I couldn't find anything specific on. And I said, as far as I know, no one's put one of these in a hypersonic wind tunnel, but if you do, let me know. And you know, I had my theory about how it would heat up and some of it would ablate and, you know, break up and be blasted off. I got a letter some years later from a couple of physicists.

who said, hey, we had a hypersonic wind tunnel and we finished all our experiments. So we went out to the shop and got some steak and we decided to try it. And it was really cool. And I would say that kind of quantitatively, I feel like I had it about right. Like I had the temperatures. I had the heating, the surface. You know, it would heat the surface, not propagate to the interior. the surface would blacken and eventually, you know, be vaporized away.

I think I didn't appreciate quite how grisly it would be. I saw some pictures that they sent, you know, the cool diagrams and everything. But boy, a steak that has been heated in this manner does not look as appetizing as. I was still imagining a steak with like a nice crisp crust. It looked more like the edge of a carpet when it's been worn away. way, you know, like just frayed bits sticking off. I didn't quite appreciate how much it would fragment in an irregular way. Not going to replace the cast iron skillet as a way of making the stakes.

But of course, then that raises all these new questions. Like the inside of the wind tunnel after this experiment, did they get yelled at? How did it smell? Yeah. They did apparently finish that they're getting their degrees, that they were there, their dissertation, they were there for their PhD work. And so they did apparently get to keep using the wind tunnel. Well, it is one of the things, I was going to get to this later, but you're bringing it up right now, which is that you're not aiming, I guess, at the middle of the population

distribution in terms of your audience. But because of the internet, et cetera, because of the, you know, way that you can reach tiny minorities of people, you can aim at those kind of people, you know, the, the, the, geeky, inquisitive physicists who are going to say, like, yes, this does sound like fun. And you found enough of them to build up quite a big audience. Yeah. And I mean, it's really cool to, you know, be able to to come with my answers and then, you know, and then find out like, oh, this expert is able to answer it better, you know, has some some data that I didn't have.

I think that the neatest effect of that has been that it's made me feel like, oh, now I have a book I'm writing. It's reaching a real audience. I can sort of feel justified in going and bothering someone who, like the people sending me questions, you know, when I started out, you know, who I just sort of assumed, well, but they have something important to do. I shouldn't bother them about this. And what I found is like reaching out to scientists is like, they're really nice.

They're, you know, even, and even if they aren't familiar with my, my books or comics or whatever, it's like, people are just excited to talk about the things they work on. That's true. You know? Yeah. And so like, like these silly questions, they'll, they'll be like, oh, yeah. You know, we've, I've wondered about that too. Here's the answer. You know, here.

Or like, sometimes it's like, that's a ridiculous question. But they're like, oh, it's a ridiculous question because of this cool thing you don't know about, you know. And so I feel like it's always, it's always a really fun conversation. and I've always had, it's, it's just been really cool to reach out to people who, who, who, who know stuff directly as sort of a supplement to, like, reading all the stuff they've written and published. It's why I started a podcast. I completely agree. Like, now I have a little license to talk to whoever I want to about all this cool stuff.

Oh, it's so much fun. Well, and I, I don't know. And it's cool writing a book and then getting to talk to people who, who do cool science stuff and then podcasts, uh, uh, who, you know, it's, it's everything I can do always in these situations, not to turn the interview around and be like, okay, but listen, tell me more about the early universe. You know, tell me more. Well, you know, look, I was talking to Darrell Mori, who is an executive for the Philadelphia 76ers

and one of the leaders of the analytics and statistics in basketball movement. He was a guest on my podcast. And you could tell, like, at the end, we were reaching the end of the conversation. He had to, like, go make a trade or whatever, and he was getting a little antsy. And then I said, you didn't even ask me about dark matter yet. And then we went on for another 20 minutes when he was asking me questions about dark matter. You're very empowered to do that if that's what you want to do. But first, I do want to ask about the, there's a certain skill set in picking out the questions

that are asked. There's certainly skills involved in answering them. But then, of course, in doing the research to get the right answer. But then there's a third skill set in presenting the answer in a compelling way. And obviously, humor comes in, but also it's a wonderful education in problem solving. I mean, how explicit is. is your intent to walk people through exactly what you were thinking to get these kind of answers? Because you're very good about giving the answer right away and then explaining how you got there.

Yeah, I think the way I usually approach it is not, like, when people are trying to simplify things, and I think this is especially something that people with a scientific or academic background struggle with, is there like, well, do you want me to talk? to my audience like they're like really slow, you know, do you want me to, to like, and they sort of will, if you try to tell them to simplify things, they'll like really start condescending to people. And so I try not to do that. The way I kind of approach this stuff is to imagine, you know, I've just spent six hours researching with all these dead ends and random side paths and like, I have, you know, 50 tabs of PDFs open.

And I've got an answer. And then I think, okay, if I went back in time and I was going to tell myself, hey, I figured it out, I'm going to save you all that time. What would my cliff note summary be? You know, okay, here's the stuff that you need to understand, to understand the answer. Here's the answer. Here's cool stuff that I found in the way that you're not going to want to miss, you know?

And I try to take that approach is just, like assume the person is interested in the question because I was interested in the question. Now, how do I get it across, you know, all the cool stuff that I found in the minimum time, you know, in the, like, like, I don't, I don't, I try to assume that the person I'm talking to is, has a lot of other stuff going on in their life. You know, they're busy. They're, they're interested, but they don't have infinite time to, like, follow me on all of my, little blind alleys and stuff. You know, and so I'm just like,

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all of your dead ends. Yeah, and that's, I think, you know, maybe the reason for some of that showing the process. Some of it is because, you know, it's cool to show how this stuff works, and it's important to bring people into science and show them how, you know, how you can use these tools to solve a problem. But I think also another part of it, and I never really thought about this before, but is that like an explanation that doesn't show some amount of, like, how you got there and why you think that's satisfactory, like just raises more questions. You know? Sure.

Like, if you answer a question of, you know, why is the speed of light what it is? And you're like, oh, well, it's because it's this over the permittivity of free space times the permeability of free space. You know, you're like, okay, well, wait, now I have two new questions. And, you know, what are those two things? So, like, you have to explain, like, why did you think that was helpful? Like, why did you know to go there? Like, what does that concept mean?

How did it connect up? you need to give a little bit of, like, figure out, like, if the person isn't going to know what that word means, that answer is not going to satisfy them, you know. Well, it makes me think of answers to math problems that always include a step like, now change variables so that X equals the hyperbolic cosine of theta. And you're like, well, why did I do that? Like, how did I get there? And that little bit of insight into problem solving, I think it's, you know, it's maybe the most valuable aspect of the book. We don't really need to know what happens when a baseball goes at 0.9, the speed of light.

But the process of getting there is just fascinating. Yeah, yeah. And like the secret is, you know, one of these questions might be like completely ridiculous, but the math that you're using is the same as math that you'd use to answer a very practical and important question, you know. And so like, like, you know, there are, like the thing about the geyser and, you know, getting launched up into the air is, like, no one's going to go and read this book. and, you know, I certainly hope get themselves scalded to death by going in Yellowstone. No one has ever been launched into the air by Yellowstone as far as, by Old Faithful, as far as we know. But, you know, the equations for like the way that the gas flows out of the mouth of the geyser is, it involves these really cool, like, choked flow equations that come up almost everywhere when you do any kind of fluid dynamic problems.

the momentum coming out is like the mass flow. You can just use the rocket equation to figure out what momentum is being transferred there. And all of those are like extremely common, extremely practical, extremely useful mathematical tools. And I also think of the question that you got about how many, how big would Google's data centers be if they were all on punch cards? And instantly, if you're me, your brain goes, well, that's not hard. Figure out how much data is on a punch card and how big they are.

and then, you know, multiplied by the size of Google's data center. But you don't know what the size of Google's data center is. And that was a fascinating detective story, right? Yeah, yeah, it's fun. I mean, we still don't. They are not very public about that. But it, yeah, it's surprising which pieces of information turn out to be hard to come by. Like, and in that case, you know, it was actually really hard to even get an

of magnitude estimate. You had to be like, okay, well, like, they haven't, they could, they've, they can only have so many buildings. They don't occupy a majority of the Earth's surface, you know, but they, they could have enough room to fit, you know, okay, how many hard drives does Earth manufacture? They can't be buying all of them. So like, that puts a bound on it. You know, you can get, you can put bounds from different directions.

You can say, well, how much power are they using? In some places, they have to. to contract with municipalities and have public records of what power they're consuming. So you can learn something that way. And then you can be like, okay, how much power does it take to run a server? How many drives would be attached to a server, et cetera? And yeah, and you just kind of keep coming at it from different directions until you find kind of something that hem's in the answer to be like, oh, it's probably in this range.

To this day, Google, they did send me a whole puzzle with punch cards that I had to decal code. And when I finally did, the coded message was no comment. But you could have guessed. I think, I think, you know, at the time that I did that, I feel like I got it pretty close. You probably got it right. Yeah. They wouldn't let you know, but they were interested enough to respond in some way. And the other part of the process that I really, really like, is, and I think you've mentioned this, but it's not just the most direct. question you could try to answer. They're always tangible, right? They're always like something you can touch and visualize and then put into absurd situations. And even though, like you say,

maybe the equations or the principles that are involved are common to other kinds of questions, there's something visceral and really connecting about that way of exploring the physics and the engineering behind them. Yeah, I think, yeah, I like the really practical. practical questions that I don't know the answer to that like someone one of the ones in the in the book someone asked about about what happens your tires get smaller as you drive them so the rubber on the treads why aren't our roads getting thicker as a layer of rubber builds up where is all that rubber going and and that it turns out it turns out it's going everywhere and it may be a huge problem and no one knows how to solve it. So I was like, this is an unexpectedly good, important, and alarming question.

But then, I don't know, I think some of what's really exciting about this, like with the baseball question and with some of the other ones I got to tackle in this book, is taking something really extreme and imagining touching it. I think the single,

maybe my favorite question in what if two, if we can, now that we're, you know, however many minutes into this podcast, I can sneak out that tidbit. I think there's someone who asked about, they said, okay, the sun, it's getting hotter over time, as it ages. At some point, it's going to, you know, explode slash collapse into a white dwarf, which will be extremely hot, and then it'll thermally cool over, through a couple of processes for billions of years.

So at what point will it be room temperature? And can I touch it? And that was one where I was like, I knew in principle that the white dwarf stars in our universe are cooling down over time. All of them are still hotter than the surface of the sun is now. They're all in the tens of thousands of degrees, I think, because the universe is not old enough for them to have cooled.

But I hadn't, until I thought about someone saying, okay, so I'm going to go touch one, when is it safe? You know, I hadn't really thought about the idea of a room temperature star. Right. But like that's going to happen. Yeah. And it's going to happen in not that many billion years. Like, I was surprised that like it's more than the current age of the universe,

but not that much more. It's like in that order of magnitude is when we'll start getting room temperature stars. Interesting. And then it immediately raises all these new questions of like, so you have a ball that's the size of the earth. Really strong gravity, but so you couldn't visit the surface. Yeah. Because it would crush a person. But it's not like a neutron star.

It's not gravity so much that no structure can survive on the surface. You know, you could, you could. in principle, come up with some kind of a solid state probe. And then I got to think about, how would you land? Okay. And I try in the book to come up with a plan, and I can see right now you've just gotten this look as you're like, well, I mean, okay, could you? You know, starting to think, it's like getting a song stuck in your head. Once you hear the question, And it's like your brain will never be fully engaged in what you're talking about because in the back of your mind you're still thinking, well, okay, could you, with a nuclear, no, what if you orbit? Okay, what are the tidal forces, you know? Yeah, no, I'm thinking like, how big could a cube of iron be and still maintain its structural integrity in that gravitational field and things like that?

You can have a person sized one. You can have a, you can build some structures on roughly a human scale of sturdy materials. What is the atmosphere like on a room temperature neutron star? I mean, there's probably a solid surface, but then there's something on top. Yeah, and this is all hypothetical. There's a couple of papers on this. You don't get the, you get some amount of sort of sorting at the surface from the gravity, pulling the heavier elements toward the middle.

Because of the extreme gravity, you don't have a wispy gas kind of at that low temperature. it's not going to be a free-floating atmosphere for the most part because it's, you know, the individual molecules are, don't have enough kinetic energy to keep themselves up in the air. You know, they stick down to the surface. You might have a little bit of a hydrogen haze. Okay. Depending on, but, you know, I mean, right now the sun has the corona around it, which is extremely hot for reasons that have never been totally clear to me. Anyone else for that matter? It's an ongoing problem, yeah.

Yeah, and so, like, I don't know, maybe there'd be something weird going on with the, there are going to be some intense magnetic fields here, I think. I'm not totally sure. But, you know, who knows what, like, it's possible you'll get a bit of a haze. But then, like, thinking about the haze, I realized, so when I, it wasn't until I sat down to try to draw this scenario. You know, I'm thinking about this. I'm picturing a room temperature star, picturing landing on it, picturing, you know, what would you experience?

Like, what would you encounter? But it was until I drew it, I draw a circle, I draw a space, I draw the spaceship. I'm like, I'll make space black, you know, it's the background. And now I've got to draw the star. And normally when you draw a star, you're like, well, this is bright. But then I realize it's not, it's not emitting light. So the spaceship will need headlights. And so I drew the star being, and then I drew a little spaceship,

and then I drew like headlights illuminating the star, because you need to be able to see it. Yeah. It's out in the middle of space. Super heavy rock at that point. And that somehow that idea of just like having to shine a flashlight at a star to see it, really just I cannot quite get that picture out of my head. Like that's just so strange.

And it would never have occurred to me until I sat down to try to draw it. But like you said, it's not a neutron star. So the gravitational field is not so strong that you have to worry. about the bending of light from the headlines. Yeah, yeah, it's pretty, the light's moving pretty normally. But you're still going to be getting up to, you know, non-survivable speeds as you plunge toward it. You know, the speeds, speeds where it's like you're going to start measuring these speeds in C

instead of, you know, meters per second. Good. We're getting a lot of good safety tips here from this podcast conversation. It's very practical. Yeah. Yeah, yeah. It's, you definitely, if you approach the star to within the distance of the sun's current surface, that's around the point at which you're now too late to turn around and escape. Not because of black hole style, like there's nothing to physically escape, but that's the point at which the acceleration it's going to take is going to flatten you to the floor of your spaceship.

Good to know. So now at that point, you'd better have figured out the line. So, like, if you're going to try to do this, you've got to figure out the landing plan before you get to that point. Because at that point, you're committed. So this, I mean, this leads me into something that is a common question to both, you know, the book and other books you've written. And, uh, XKCD, the comic, which is there's sort of a, it's quirky, right? I mean, your comic is not the same as, uh, Dunesbury or Peanuts or whatever. There's something different about it.

And sometimes there's not even. a punchline. Oftentimes it's not even a punchline. It's just pure, here's something cool or here's something to think about. How explicit is the balance that you have there? Do you have to remind yourself, well, I need to throw some jokes in to keep the audience happy, or is it just like you go with what is cool to you and hope the audience comes along? I think, I mean, I think it's definitely, you know, go with what's cool to me. Part of it is like, like, if I'm going to, If I'm going to post a comic, if I'm going to write something, you know, not, I think that you can only go so far analyzing this stuff before you kind of, if you think about tying your

shoes too hard, you stop being able to do it. So I never, I don't know, I think, I think that to the extent that I try to balance it, it's mostly like, I just think like, I'm going to show this to someone. so I want to make it worth their time. Either there's a good punchline at the end or there's something so cool and interesting that they're not worried about a punchline. I just don't want them to be finished and be like,

okay, why did I read that? Sure. So that's why I just try to think. Like if I have a really cool way to visualize something, you know, I feel like that'll speak for itself. And then sometimes you can put in some jokes here and there too, just to make it clear. People don't have to be studying this, you know.

But I think sometimes that's the punchline isn't even the destination. It's just the thing that reassures you that we're all just hanging out here. This is fun. Yeah. But I mean, there's definitely sometimes it is like just purely a really cool infographic, right? I mean, I think of like the Lord of the Rings characters talking to each other or the money plot or whatever. I mean, it's just there's like you say, there's little jokes in there. But it's just thinking about things in a slightly different way.

Yeah, yeah, I mean, that's one of the things that's the most fun about this job is being able to kind of just decide what it is I'm going to be doing today. You know, like what this, with each comic, you know, it's just, it has to be something I think is good and I think people will like. And I get to explore, you know, if I'm really interested in this particular idea or this particular thing. But a lot of those really big charts and, you know, that kind of comic where I'm like, visualizing something or cataloging something. It's like it started off as just my notes to myself. You know, I'm just trying to understand this thing. And I'm like, okay, wait, there are too many different numbers here. I need to write them all down, you know. I need to put them in some visual form so I can like make sense of them. And then like, I'll do that. And I'm like, oh, I wonder

how this other thing compares to that. And I'll go add that in. And then before I know it, it's become this like sprawling catalog. At what point in this process, because you originally, or at some point, You were just working for NASA before you started XKCD. At what point did you realize that Don to you, like, I'm an artist. That is my job. I don't know. I've always, I always feel a little, it's always a little bit strange when people will get really weird about titles or, you know, like defining whether or not something is. art or defining whether or not you count as an author or if you're a and like I can see

sometimes if you're um you know trying to establish your legitimacy um and that people you know you have a right to be taken seriously like I I would say I get called Dr. Monroe a surprising with surprising frequency. And I don't worry about what name people are using for me, but that one does bother me just because of how many women I know do not get called doctor even when they have, you know, they do have a PhD. And so that, that makes me want to be picky about that. Sure. But, you know, that's just so like with like, people are like, oh, is this, is this art or not? Are these comics or not, are you an artist? And I know that's not quite what you're asking there, but it is something like, I know that when there's another comic dinosaur comics that started

around at the same time I did, where it's the same six panels every day, just new dialogue, same six pictures of dinosaurs and it's, you know, clip art. And people spend a lot of time trying to decide, is this really a comic or not? And I'm like, I don't, I don't know. So who cares about that? It's awesome. Exactly. But nevertheless, since you're not just using clip art, you do whatever the labels are or whatever the legitimacy is, you need to make artistic decisions, right? Like, you're using stick figures. There's a sense, there are questions about how expressive you can make stick figures. Is it a limitation? Or, you know, like, how do you, do you, I'm not quite even sure what the question to ask is, but how do you approach the craft of, you know, know, you're trying to say something funny or illustrate something cool, but you're also drawing it, right? And, you know, that has to come into the best way to do it. Yeah. I don't know. I don't know if I have a satisfying answer to that. It's, I guess, a lot of trial and error.

I read a lot of comics growing up. Okay. You know, one thing I found surprisingly helpful, so I haven't, as someone might guess, if they were inclined to be, judgmental. I haven't taken any art classes. I did take a technical drafting class at one point. And that ended up being really helpful. And I sort of think my, one of my small opinions is I feel like anyone who does physics should have to take a class in perspective drawing just for the part where you're drawing on the board. Okay, you've got the plane of the so and, you know, you've got the particle moving in this plane, and then perpendicular to it, you have this force, and now you have another surface here, and I just have so many memories of my physics professors drawing the front

face of a cube, and then the back face with a different angle, and then they've got this, like, Picasso-like construct, and I'm like, okay, I, you know, this is the one thing where, like, it would be so helpful. It's really helpful to be able to take a picture and just figure out, like, where do these lines roughly go? Right. And I think that's helpful, like, outside of comics. You know, it's helpful in physics. It's one of those places where I think the art can have,

like, very small kind of communication-y way inform the actual process of the science. Well, and also we seem to be, I mean, I guess I should phrase this as a question. Are we still in a sort of a dynamical discovery kind of phase in the history, of webcomics. Like, they're clearly a different thing. You can use them in different ways. Dinosaur comics is something that probably would never have gotten a lot of daily strip use in newspapers back in the day. And then also you can use the technology in fun ways, which you've done in a couple of XKCD strips.

So are we, have we tapped that out? Or is there like a whole new frontier we haven't explored yet? I don't know. I feel like it almost turns into a little bit of a categorization question again. Like, you know, in all these different mediums, we mess around with like getting things across visually with pictures that are grouped together with words. And, you know, there are different conventions and then you lean on the conventions and, you know, use that to say things and you subvert the expectations. But it's,

but, and like, I think there are always new ways to do that with new mediums and, and, and it all kind of bleeds into, into itself. Like, you know, like when I started doing comics, memes were, like, around, but kind of a very different thing. and then they slowly evolved. And like you now get things like, like the distracted boyfriend meme is just like the one that came to mind first.

Just now like that, it's similar to comics. You know, you're like, you're taking this picture and assigning things to it. It's like a political, it's very political cartoon. You know, it's very much in that mold. Is it a web comic?

I don't know. That's one of those things. Like, I don't really care that much. And it's all, you can call it. You can decide how you want to group it and categorize it. But it's like it's a cool way to get across a point using these tools. And, you know, I think that's neat and fun. And that's exactly the way that I would go.

I mean, forgetting about the categorization ahead of time, let's let the thing be what it is and see how it evolves into. And maybe we'll discover some new things. I mean, you, I would imagine that you do more programming and script. than the typical cartoonist. Yeah, yeah, I think that's probably a safe bet. Although a surprising amount of it is like part of the writing process. Like most of the interactive stuff, almost anything that you interact with in code, I've worked with someone who does JavaScript, who handles that better,

like anything that's going to be public facing like that. What I'll do is programming like for there was a comicated a while ago that was Wikipedia article titles that you can sing to the tune of Teenage Mutant Ninja Turtles. Okay. Ace Ventura Pet Detective, single payer health insurance. You know, you can sing it to the Ace Ventura, Pet Detective, like the Teenage Mutantia Turtle's theme. And so I made a whole list of these. But it's not just any like eight, you know, any word with like the right number of syllables, any eight-s syllable.

You have to have the right patterns of stress. Right. And like, that's actually kind of tricky. So I like got like a language processing library, figured out how to use it, figured out how to get like extract syllable patterns from words and stress patterns, which meant I had to learn how to interpret those. Like it was, they have a whole like system for this. And then get something, download all of Wikipedia's articles, run them through this.

generate a list of candidates, you know, filter through it. Like most of the work there was just the programming. You know, most of the work there was learning how to use that software. And it was just because I wanted to make this joke about, because I had noticed one or two articles that you could sing to that. How many titles are there? The, the, I ended up publishing a comic that was mostly just a list of them, you know, which had a few dozen, you know, maybe 100.

The total number of articles that technically qualify, I think, is probably in the maybe tens of thousands, maybe thousands. Okay, so you picked out your favorites for the comic. Yeah, so I could skim through and find the ones that worked the best. There is something about the, again, this is a very vague kind of question, which maybe there's no answer to, but there's something about the style of XKCD where, you know, you put your fingers on things that are pretty familiar to. a certain segment of people, right? There's a reason why people say there's an XKCD for everything, and a lot of scientists and engineers have XKCDs on their doors and so forth. So the impossible to answer question is, you know, like, how do you distill these little bits of truth down to a comic, or, you know, how do you put your finger on these things that everyone goes, oh, yes,

right, someone is wrong on the internet. I have spent that night. man I don't I that's another I don't know I think about the stuff that that I have strong feelings about and or that I notice and then I think you know what is this is this a common thing but like it's not always about just like I'm going to try to find something relatable or you know I'm going to I wonder if this is a universal experience some of the you know the the comic that you just mentioned about like someone is wrong on the internet where I did this comic about this phenomenon of like not not being able to drop something because there's someone out there who has a wrong opinion and you need to correct it. You know, they're wrong about something. I partly drew that one just trying to call myself out. Like, of course. It's like I catch myself doing this. Okay, I'm going to do a whole comic about it. And that will both serve to, you know, just drawing it and making it explicit. Like it's a reminder to myself. Like, oh yeah, this is a thing that's easy to get sucked into and I should back off. You know, I should remember not to not to get too caught up

in wanting to correct someone. But also, it worked extra well because let me tell you, nothing takes the wind out of your sales, then you think you're making a really good point and then someone else quoting your own comic back at you. Oh, yeah. Okay. So now I have to be careful not to go too overboard and correcting people because they'll just reply with a link to my own comic.

I mean, do you have to like index all the comics you've ever done to make sure that you're not telling the same joke multiple times? Definitely. I mean, but I have that problem in real life. I'll tell a story. I'll have a really good little story. You like, you forget which, it's like you have to keep a table of which of your friends you've told the cool microwave story too. It's terrible. And otherwise, you start into it. And they're like, yes, we know this one. You told us last winter and also at the party before that. Is there, do you feel different like when you're doing the comic versus a book like, what if? I mean, the comic is supposed to be, presumably mostly entertaining and the book maybe is mostly informative or is it just whatever is working in the moment? I think I think when I'm writing what if I have a goal,

which is I want to get the answer. And with the comic, it's a lot more like I have to show why I introduced this topic. Like you can't, you can have any kind of a sketch or a movie or a show, you open with something happening and you start watching me, like, all right, I trust you're going somewhere with that. And so you have to then have something to make it worth their while. With what if, it's like, I open with the question. Now we're all on the same page about where this is supposed to end. You know, like, we want to know the answer. Now the question is like, what's the route to get there and what's the weird stuff along the way? So I guess it's almost like an episodic versus long arc kind of storytelling. Like, you know, you have the buy. You have the

buy-in from the audience, presumably, if they bought a book called What If, they know what they're expecting. But in the comic, every week is it that you put up a new comic? It's three times a week. Three times a week, yeah. So you have to sort of reestablish a premise and get to the punchline in a very short number of words, right? Yeah, yeah. It's, man, nothing will make you edit yourself down. Like, especially, I mean, I handwrite the text in my comics. And, yeah, nothing, having to actually write out all those words really makes you realize how much, how many words you've written. That's one way to keep your word count down. But your handwriting is very good.

I wonder if that's possibly part of the drafting class you took. Because I also took a drafting class, and the only thing it did was improve my printing. Yeah, no, I think handwriting was the first class I got a bad grade in. Yeah. Like you reach the point at which they start giving you. grades or marks and and you know and then a year into that uh i think i got my first you know c or d or something in the handwriting class and i was like okay well i'll just accept that handwriting isn't my strong suit um and then i you know i went on to get many other Cs and Ds uh but i it is funny that that's

the career i ended up in was i do more hand lettering than almost any other job nowadays but maybe this is a i mean a good place to wind up because you know joking about not getting good grades in school but look, there's no super strong correlation between getting good grades in school and being good at things. There's a kind of thing you can be good at that requires that you get good grades in school. But, you know, you have been able to find a niche for doing something that you're very, very good at, even though the whole job you have literally didn't exist when you were born, right? You didn't grow up wanting to be a web cartoonist. So is there any lesson here that we could get?

Is there anything that you can think about about finding a way to get your talents into useful channels for the vast listenership out there? I don't know. I feel like it's always tough to ask someone who's like, you know, if you get someone who's successful at something and you're like, okay, what advice do you have? It's like you're really sampling from a pool of people that's selected here. It's like if you only interview lottery winners and you're like, what's the secret? And they're just like, you've got to buy a lot of tickets. You just got to keep buying tickets. Don't worry, it'll pay off in the end. I'm living proof of that.

You know, so it's like, I don't know. I mean, I know what worked for me, but I don't know how likely it was to work. You know, I know what, I think that, I don't know, I think that I, I was lucky in that I just kind of put stuff out there and paid attention to what was working, what people, you know, like, when I originally posted my comics, I wasn't really thinking about. I didn't think that there would be an audience for it. And then I was surprised when people started sending some of them around. And I was like, oh, this is connecting with people. Cool, I can do more of these, you know.

And I don't know. I think there's an amount of like a combination of being really confident about like, hey, maybe someone is interested in this. Maybe someone wants to do this. I'm going to just plow ahead with this. I think there's a combination of being confident about the things you're interested in and the things you think are cool, you know, the things that you're excited about and trust that like there are other people probably share those feelings.

And also like being aware of whether or not the way you're communicating with other people is working right or not. And kind of accept that, like, I think this is advice that goes way beyond comics or even creative work or careers is just like

communicating with people is hard. And so, and like fundamentally the only measure of whether you're doing it right is if other people are getting the message that you want them to. And so you kind of have to

go into it with this humility of like, if I say this and people are taking the wrong thing from it, you know, I can't control everything about how they feel or I can't take responsibility for all of that. But also, if I'm not getting the response that I was going for, then what am I doing? Like, I should try something different. You know, if, like, we're all just trying to connect with each other and get on the same page with each other about all these things. And I think it's, it's good to have sort of a humility about, like, if I use this word and people understand, are understanding me wrong, I can be like, well, it's because they don't understand this word. It really means this. And I can just be angry all the time. Or I can be like, okay, what words would get this

across, you know? And I think that going into things with a little bit of kind of humility and willingness to self-correct about that kind of thing is really helpful because otherwise you just get more and more angry and lonely. Yeah, look, I'm actually quite skeptical about advice as a genre in many ways, because people's situations are always very different from each other. But that kind of sort of general thing to keep in mind can be useful. I mean, maybe to end on something more concrete, but along the same veins, am I crazy to draw a connection between things that NASA does and things that you do? I know that you worked for NASA, but in some ways, NASA is an example of a bunch of people who are faced with these real-world versions of what-if questions? What if we needed to

land a rover on Mars without it crashing, right? I mean, there is some, the what-if questions are great because they're absurd, but the lessons that we learn from them are actually kind of important. Yeah, I think something that I really, like something that I think is really unique about NASA compared to a lot of the other, you know, big places where there's a lot of interesting technical stuff going on, is that they are tasked with doing things for no reason except that we think it's a good idea, like collectively as a society, to do this to learn more. It's like very, you know, like there are benefits from the things NASA does, and a lot of the stuff they do teaches us about the world, which is important because the world is where we live

and might, you know, destroy us at any moment. So it's important to study it. It's self-interested in that way. But finding out was their life on Mars, is their life on Mars? It's something we want to do. We don't want to do it for a reason. We just want to know. Like people are curious.

And NASA is just like they are working on these problems because they want to know and they are acting as our representatives. You know, my representative is in my country to go out there and work with these other space agencies and solve problems that there's not necessarily an economic incentive to solve, or that there's not someone who's gonna pay for it. It's just like, we've all decided,

we wanna know what's up there on those moons. Let's pick some people and have them, you know, go figure it out. And I think that's really cool. It's just answering a question because we wanna know the answer. And that's, I think that's a good thing to do sometimes. And I bet that there's some young people out there who will read your books and be inspired to do exactly, that. So I hope that they do buy them.

Thank you. Randleman Rowe, thanks very much for being on the Winescape Podcast. Hey, thanks so much for having me on. It was so much fun to talk to you. Great. Take care. You too.