How to see pictures of dinosaurs (featuring XKCD creator Randall Munroe)

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Speaker 1: Daniel. If you had a tough problem to solve, who would you ask? M M. I guess it depends on the problem. Is it like a particle physics calculation or something like a tooth extraction? Well? What if you wanted to do a tooth extraction with particle physics? Well, you know, usually you get the ideas nailed down and then you just sort of hand it off to an engineer and they figure out the details. Like we're like engineers are to steer assistance, Like we're just there to fix your problems. You know, they're downstream, That's all I gotta say. I don't know which position is better. Stream you start with the man, I see, I see. You mean the bad ideas just flow down. We flushed them to track the engineers, and the engineers turned into gold trickle down physics, I guess. But at the very top, of course are the comics. Hi'm Joramade, cartoonists and the creator of PhD comics. Hi, I'm Daniel. I'm a particle physicist, which puts me solidly downstream on the intellectual river from cartoonists but above engineers, thank you very much. And I'm a professor. You see Irvine. We're actually do experimental particle physics for a living, and I'm the co author of our book, We Have No Idea, A Guide to the Unknown Universe. Yeah, and so welcome to our podcast, Daniel and Jorge Explain the Universe, a production of I Heart Media in which we examine all things crazy and awesome about the universe, things far away, things nearby. We ask all sorts of questions on this podcast, and so today we'll be answering a couple of questions. But we're gonna do things a little bit differently today. So first of all, we're going to be answering how questions? How two questions? And second of all, we're going to be doing it with arguably the world's worst expert on how two questions? So this is in some sense another episode of Ask the Wrong Expert? But is this guy an expert in everything or nothing? Well, if you are on the internet, if you have access to the Internet, which we're guessing you have because you're listening to this podcast, thank you, yeah, thank you, thank you government agencies, and you have an interest in physics and science and math and geeky stuff, then you've probably most likely have come across the work of our special guest today. For those of you listening on today's podcast, I will be the only one who is not a famous web comic, and I'll be the only one who does not have a degree in physics. One of these things is not like the other one in every sense of the word. And so today on the podcast we have New York Times number one best selling author of what If and the creator of the super popular web comic x k C D Random one Row. Welcome, Randall. Hey, thanks for having me. It's super special to have you here today because not only are you a cartoon robotisist who turned into cartooning just like me, but it's pretty cool because you're awesome. Feeling kind of left out here, You don't have to have a robotics degree to be in this podcast. We'll find a connection for you the later. Daniel, Yeah, you you used to work at NASA, right, Randal? Yeah, I worked there on three D vision stuff for a while as an intern and then uh and then got hired to work in a robotics lab on robotic navigation. Cool, and at some point you decided to become a cartoonist. Yeah, Um, I was working on a contract basis in NASA. And at the same time I was posting my comics that I had was mostly like doodles from my old notebooks. I was scanning them in and putting them on my website. And then at some point people started sharing those around and asking if they could order t shirts or prints of them, and uh, and then before I knew it, I was like spending a fair amount of time shipping merchandise and handling that stuff. And and so when my contract ran out at NASA, I didn't I didn't push them to take me back. I was just like, y'all try doing this comics thing for a little bit. And I noticed on your website you have all of the old original ones, like including like number zero, And I wonder sometimes, like you ever thought about, like, you know, going back and editing it, or do you keep all those on there for inspiration for future people trying to launch their own side careers or I don't know. I try not to do the thing where I go back and add c G. I uh, you know, walking the camera and stuff. But you know, um so no, I I just think of it as like I posted it, and that's like the record of old of old stuff I've put up. Yeah, you get a respect to archive, right, Yeah, exactly calls robotics Randall working on robots, um. I don't know. What I like about comics is that when I can think of an idea for a robot and then draw it and then it'll do what I want to draw it doing. Whereas in real life building a robot like way more of it was spent like debugging sensors and trying to figure out why, like why will this half of it not turn on? Everything is working right, it works right when I take it out of the robot. What's different? You know that kind of frustrating debugging. So comics are fun because that you can you can kind of skip all of that because you get to just draw the robot doing what you wanted to do. The real world is very frustrating sometimes, I agree. Well, thank you for joining us today, Randall. I know that you've been criss crossing the country and giving talks and giving book signing UM to talk about your new book which is called it's called how to Absurd Scientific Advice for Common Real World Problems. Yeah, and so it's an awesome book. If anyone out there is listening and wants just a really fun read to learn about science and physics and do it in a way that is intrigue and interesting. So tell us a little bit about what the book is about, and maybe a little bit about how you thought about the idea for the book. Well, I'm I'm always thinking of like wildly and practical ways to do things, which which isn't usually my goal. I'll just be like looking at a task, and especially if it's something that's kind of repetitive or menial or like you know, boring that I have to do a bunch of times, and I'll think like, are there any other ways I could do this? And I'm not trying to think of bad ideas, you know, but but most of them are bad ideas or at least impractical in one way or another. But what I find is like going over those ideas and kind of taking them seriously for a moment, like as a as it's like as a hypothesis, and then thinking like how would this work? What problems would I run into? Uh? And and like what would then what would the side effects of doing it with this way be? How hard would it be? How expensive would it be? Um? That's always really fun. It's like I like that kind of analysis because I really like, like, I really like doing math and and engineering and planning when there's like a cool goal in mind. I always have a hard time with when math gets really abstract. For example, like I see an equation on a board and I'm just like, oh, I hope I don't have to solve that. But if that equation will tell me whether there are not I can attach engines to my house and make it fly into the air. Like suddenly, I'm way more interested. So I was like, like, practical applications. Wait, so wait, I thought I thought you told me earlier you were physicists. What is this interest in like real world applications? Well, oh those? So I feel like I get along so well with everyone who does physics um and I And I think the reason might be, like the way I see it is that physics is for people who are too um, too practically oriented to go into like pure math, but then at the same time like not concerned enough with details and implementation to be engineers. So if you wander back and forth between like the theoretical and the practical, you have to walk that like narrow path, but that takes you into physics because if you're too interested in the abstract structures that you know, theoretical structures explaining things, you get peeled off into like algebraic geometry eventually, and and that has no connection to reality. Yeah, who needs lee algebra? Right? But if you actually uh, actually out after tracked, algebra has a deep, deep connection to reality. Underlies the connection is that it funds to pull a bunch of mathematicians start I always feel bad using algebraic geometry is my example of a thing that I'm not interested in because I'm like, I'm so sorry to any algebraic gey im a trists out there. But yeah, then but like at the same time, like I wanna you know, I want to practical application, etcetera. But then like actually building robots, I quickly get frustrated with like the practical aspects of it and just want to think, like, theoretically, how would this robot work if I had solved all these minor engineering problems, So like, yeah, right in between the theoretical and the practical. I totally agree with you, though, the best part of the problem is when you can just hand it off to the engineers and say make it work for less than a trillion dollars. Please. We figured out all the theory, now make it work. Yeah. But you know, we were talking earlier a bit about how it's sort of not just about um making something or achieving something or getting to somewhere. It's it's about but sometimes you discover along the way, and when you're in the process of getting there, where your curiosity sort of leads you in in in finding new things that you maybe didn't think about. Yeah. I really find that a lot of the time, especially with computers. I'll have an idea for how to automate something that will save and I think it'll take a lot of work now, but it'll save me time in the long run, and it never saves me time in the long like it's always I would have been better off just continuing to do it the other way, but in the process well, and but in the process of building the automation too, I'll like learn to use some software library that doesn't actually help me with the problem I'm working on, but now I know how to use that software, and and then later on when there's a problem where it is actually really helpful, I have a head start already like I've already learned how to use it. So sometimes like solving a ridiculous, you know, contrived thought experiment or word problem, or analyzing a plan that definitely won't work, we'll teach you something that then is helpful, uh with solving something else. Um. And then also it's just sometimes really fun. And so that's kind of what your whole book is about, how to answer ing sort of scientific advice for common real world problems. Uh, it's you sort of go into how to do sometimes simple even simple or seemingly simple task and you sort of, um follow your curiosity and find kind of the sometimes the worst possible way to do it, but where you sort of learn a lot and think about cool signs. I've always like hated moving because you have to pack. It's so disrupted to your life and uh and just takes over everything and takes so much work. And I started thinking, like, Okay, is there a way I can avoid packing all these boxes? And I then I was thinking, you know, my house is already a boxing structure, all my stuff is in there. Could I just lift the entire house? And like, there's no way that's gonna end up being less work than just packing the boxes. But um, you know, I'm gonna let's tryport you just maybe you know, because sometimes, uh, sometimes like almost all the time, it's pretty clear, you know, this isn't gonna be a bad idea, but like sometimes sometimes you never know. Um, the like whoever was the first person to you know, went like if you get a cut and you're like, oh man, this looks red and swollen, it looks pretty bad. I'm going to take some of this mold from a sandwich and just rub it on it. Like that sounds definitely like a bad idea, but like that's penicill and that's how that works, and that like is that the true story that discovery pill? Yeah exactly, yeah, no, um, I think it involved the earl of sandwich actually, oh yeah yeah and the duke of penicillin. You know, it was a jest. It's not like these weird ideas always turned out to be good, because like there's a lot of stuff that you could rub on an infected wound and it would make it much worse. Like so like trying to figure out just a long trail of bodies of people who rub things into their wound and but the one person who picked the right mold survived. That's right. And we can't interview dead people in the podcast, which is why you're here today and not all those other folks. But I think there's a there's a really interesting lesson here that connects, you know, not just engineering, but also physics and just following your curiosity and sometimes you discover stuff that's totally unexpected. And you know, on this podcast a lot we talked about these things like you're interested in X, and then along the way you discover why. And the universe is filled with fun mysteries to unravel, and so that's part of the joy of doing physics and sometimes abstract geometry. Alright, alright, I'll learn. We just gotta come up with a good for him to to that will require learning about that. If you want to move, you can turn your whole moving process into a computer script if you learn algebraic geometry, I promise. Alright, alright, we'll talk dot slash move dot sh alright, So to them the program, we are going to be asking you randall um, and we're going to be trying to answer together three how two questions, And so the first one on the list is one directly from your book. But before we keep going, let's take a short break. I love your book. That is hilarious And for those of you out there who are interested in science with a healthy dose of silly humor, then you know, that's probably why you're listening to this podcast. You're going to really enjoy this book. But make sure when you're reading it, you know, in a public place, or people will think you're weird for giggling so much. Um. But one of my favorite chapters of this one chapter twenty six, how to get somewhere fast. And you know, it talks all about you know, movement on Earth. But one of the most fascinating bits is is at the end you're talking about how to get around the universe right and how especially if you wanted to get to the edge of the universe in a fast way. Is that the idea? Like, how how it's the fastest way to get to the end of the universe. Yeah, well, I was thinking about how you know, they're there are all these limits of like the speed of light and stuff that the limit how quickly you can get somewhere, But there are also the more practical limits, um, if you want to if you want to travel from here, you know, to across the country or across town or whatever. Um. Most of the time you aren't limited, but you're limited by traffic or whatever. But if you are able to rid of all of those limitations, you've still got a kind of fundamental limit by how fast the human body can accelerate and over really brief intervals UM. People can handle handle fairly high accelerations, especially if you're a fighter pilot you have one of those suits with the compresses your legs so the blood doesn't all drain from your head. Over longer periods of time, we don't do a great if we are accelerated faster than you know, like Earth gravity, that's when our body squishes or is that just when we pass out? Um? No, Like the idea is that like we're always existing at one Earth gravity of acceleration um, because Earth's gravity is pulling us down and so you know, your blood is uh, you know, being pulled down to your feet when you're just standing um. Which is why like if you if you like injure something, you're supposed to elevate it to like keep it, I don't know, from keep it from bleeding, uh as much I think This is something that a lot of people don't really realize. They're a where of the fact that there's a speed limit to the universe. They don't think often about how long it would take to get to that speed limit. Right the imagine how you press the button and jo you're going half the speed of light. Of speed of light. Yeah, if you made a rocket that you know, you press a button, it moves and it's and it just accelerates up to the speed of light. If it doesn't, you know, in a week, that will be crushed against the back of the room you're in by the acceleration and it'll it'll like you'll just be a puddle in the back of the rocket, and no amount of mold will help you. With the sandwiches, you can actually be turned into it pretty tasty. Same to that point, So you're saying that there's there's a speed limit to the universe, but there's also also kind of an acceleration limit to the human body. Yeah, and this acceleration limit um is actually it does have sort of practical consequences. You're on Earth, um generally, our modes of acceleration don't involve accelerating at one g uh you know, at this high speed especially, you know, it gets added onto the gravity that we're already feeling. So if your car accelerates too fast and you're pressed back into the seat, it's uncomfortable, you know. So you have for example, yeah, I think that the very fastest cars will do about one g of acceleration sideways. Um. And that's on top of the one g already pulling you downward. And because of the way you add you know, forces that are in different directions, it means you'll be experiencing a total of about one point four ges diagonally yea, yeah, and people and that's okay, you can handle that for a while. It doesn't feel that comfortable. But at that acceleration, it takes you, you know, a good thirty forty five minutes to get around the world because you have to accelerate up and then you have to accelerate back down at the other side. Oh so if you if you do the math and accelerated that speed at that exploration and then right away start decelerating it that, yeah, exactly, then you would take you how long to be around the world. To get to the other side of the world will be like thirty forty five minutes in that range. There are some funny details there, like if you if you accelerate fast enough and you get up to a high enough speed, because of the curve of the Earth, there's sort of the centrivigal force flinging you outward that cancels out gravity um, And so if you're moving it like orbital speed, you don't actually feel any acceleration from gravity, which means you could afford to do a little bit more acceleration uh forward because you would have less force on your body that you know, you have more acceleration budget to work with. But then if you go too fast the curve trying to follow the curve of the Earth, you have to it's like you're being swung against the outside of a curved wall as you're going around it too fast, and that you know, centrivigal centriviugal acceleration of anyone how you do it um that starts to become a problem. So just like if you go too fast, sticking to the Earth is hard. That takes extra force um and an extra stress on your body. So if you wanted to go a light speed and stay on the Earth's surface, which sounds like a dangerous way to drive your Lamborghini. Yeah, that'd be a definitely a scenario where you end up as a puddle on the wall of whatever vehicle you're in. Am I the only one here who doesn't have a Lamborghini? It did I miss out on the you don't hand use the official podcast Lamborghini Coop. There's a sign up sheet outside you used to sign up. I know so little. All I know is that that car sounds fast and expensive and actually know if it's a good high acceleration comp if you wanted to accelerate to the speed of light. It's interesting, you know at one and then basically you're saying you have to accelerate at one g. That would take a shockingly long time. Yeah, it's it's actually kind of weird to me that it's it's a really long time. Um, if you're going to accelerate, I you're gonna accelerate for more than you know, a few minutes in a car or whatever you want it to be at Earth gravity, you want to accelerate it one G and not any more than that, because like long term, it'll take a toll on you. Um. But and if you want to get up to the speed of light. Uh, if you have no relativity from what I just think about how long it takes to get your speed up to around that range. It's about a year, Like it takes a year to ramp up to the speed of light. Yeah, which is both really long but also weirdly short, because I think of the speed of light as being unimaginably large, but it's weird. So it's weird that it's kind of within a human you know, time frame. Wait, I thought it was impossible to get to the speed of light. Are you saying, like, get up to the speed of light or what do you mean? Yeah? Well, so you know, to get up into the range of the speed of light is on the range of a year. But as you start to get near it, things get a little bit more complicated because that's when relativity comes in and suddenly the math stops being like addition and subtraction and involves, you know, at least a few more symbols. Yeah, it gets a little none in there, But it depends a little bit on how you state the question. Right. If you state the question is how much acceleration are you achieving, then you can say, well, I'm accelerating by this certain amount, but if that takes more and more energy as you get closer and closer to the speed of light. But it's also it's a funny sort of coincidence of numbers, Like the number of seconds isn't in a year is about three times ten of the seven, and the speed of light divided by Earth gravity is about three times ten of the seven. Sort of funny coincidence. Takes one Earth year to accelerate at one G to one C. It's like we were It's like we were meant to go at the speed of light. It also makes you wonder like if we were on another planet where the gravity was much much stronger, right, like say we're not a super Earth somewhere, and we could tolerate five G, then we could be more of an interstellar species because we could accelerate it five G. Right, So some aliens out there there are much better at exploring the universe than we are. They'll they'll get there five times faster, they'll accelerate five times faster. Right, they'll get to the speed of light faster. But you know, in the end, if you're going fifty light years, you know the times been accelerating decelering doesn't actually matter very much. I think that's what you were saying. Yeah, Well, the funny thing is with relativity UM, when you when you subject yourself to that kind of acceleration um in one sense from someone watching from the outside, Uh, it looks like you're getting up closer and closer to the speed of light, but then your speed kind of plateaus. But because of the way time is changing for you, you'd be plateauing. You know, your speed would be leveling off as you got near the speed of light. But they would also see all the clocks on board your ship running slower. Oh. I was going to ask that when you say it takes a year, is does it take a year for me on the ship in my arm light speed Lamborghini, or would it like take a year for someone watching me from the outside. Well, for the first year or so, your clocks will be mostly in sync, and then as you get near that speed of light, they start to diverge and you're for you, it feels like, uh, your clock is still running normally, You're still under one g of acceleration, and you see mile markers in the universe going by you faster and faster and faster. But part of the reason you're seeing them go by faster and faster and faster is because your clock has started running slower from the perspective of the rest of the universe, so to you, it feels like it's taking less and less time to pass each marker um. But that's that's partly because your your time is running slower. On your ship right, or another way to look at it is your stationary and the universe is moving past you faster and faster, and moving things get shrunk by relativity, and so with's a mile to somebody else now becomes smaller and smaller distance to you. This whole relativity stuff is all mind bothering, right, And the thing people should remember is that your clock always runs at one second per second. Right, clock that's sitting next to you, not moving relative to you, always runs normally. Other people's clock always move slowly. So you're on the LFE Bi Lamborghini, you see earth clock running slowly, they see your clock running slowly. And the last crazy factor remember is that people don't have to agree. Like on the Lamborghini, you can see one thing on Earth, you can see another thing that seems to contradict, and everybody can be correct even if they contradict each other, because there's no actual, absolute truth in the universe. It's all just relative. The weirdest consequence of this, in my opinion, is like that as you're excelled, if you were able to keep accelerating one g, which right now we don't have a way to do. Um, there's there's there. There are a couple of really wild proposals out there that involve nuclear bombs, uh that I'm I'm very into, but are probably not practical. To see how much he's smiling when he says nuclear bombs, But this is why I'm glad you just keep things theoretical and on paper exactly. The nuclear bomb thing is something that a couple of theoretical physicists are very excited about, and all the people who actually have to deal with like the the actual like nuclear material and stuff, are like, what are you thinking. But so other than other than those weird proposals from the theoretical physicists, we don't we don't have any technology they'll let us accelerate it one g. But we also don't have any any clear reason to think it's impossible. Um, so if we did have a way to do that, and we were accelerating, we we could get up in within a year or so to near the speed of light as and then the relativity starts to come in. But if we keep it, If if you're in this Lamborghini, you keep accelerating at that speed at one g U, your your clock starts running slower, and it feels like you're get moving faster and faster and faster. UM. It feels like you're reaching other parts of the universe in less time than it should take you. So it's as if you're going faster than the speed of light. If you sit down and do the math on what that converges towards, like how okay, if you let five, ten, fifteen years go by on your ship, you'll get closer and closes speed of light. Your time will stretch out, So it's like you're living longer and longer um, and it actually gives you time to reach way farther than you You stop aging in a way take a long time for people on Earth, you could you maybe could get to the other side of the universe. Yeah, so the you know, getting trips across the galaxy, it might be like a hundred thousand light years, so it should take you a hundred thousand years moving at the speed of light. But after those first few years, you've gotten close enough to the speed of light that time on your ship is barely passing. So someone outside watching you, it'll still you know, uh, my ten thousand years might pass at the universe in the universe, or a hundred thousand years might pass in the universe, but for you, very little time. You know, you'll get those first few years and then your clock slows to almost to stop, which is why so many listeners writing with the question what is it like to be a photon? Because they wonder like, can photons think it's time frozen for a photon? Um? And unfortunately we've never been able to interview a photon on the podcast, so we don't know the answer. We haven't won our show all the time here in the room. But you know, none of them stopped to Yeah, they they for a photon, the entire universe has contracted to a single point. They have a single moment in time, like time doesn't pass for them at all because they are moving at the speed of light. How can you even build a clock or have a clock as a photon, how do you measure time as a photon? Because you can't build a clock out of light. Everything is moving at speed of light relative to you. If there's a funny crazy heart answer watches that. Well, the coolest thing about this one g of acceleration is if you look at like, okay, in a human lifetime, how far can you get? And you find that it takes you about about thirty years to get to where you can go almost arbitrarily far, like crossing the entire observable universe. It you know, billions of light years. And it's really that's another weird coincidence that, like the size of the universe is about how far you could go in one human lifetime at one G of acceleration thanks to relativity slowing down the clock for you, right, And that's the observing universe today. And of course that if the universe was sort of static and waiting around for you to do your tour. But of course the universe is expanding, right, So yeah, that's the problem is for you it only takes thirty years, but the but for the rest of the universe, a lot of time passes. So the universe is expanding, and you'll feel like you're going faster and faster. But then you'll also be like, wow, the universe is getting bigger, faster and faster, and like the expansion of the universe is accelerating, which you know we've recently learned, but to you, it would be seemed to be accelerating much faster. It would be doubling in size in a few years. So you would actually never be able to catch up to the edge of the universe at this even even if you could accelerate to near the speed of light. Yeah, because the universe doesn't follow these rules, right, there's no speed limit to that. Yeah, well, it sounds like that's the answer to how to question? Which is it? To me, it seems like the answer is to just go for it, right, Like, don't miss around, don't go at half the speed of light, don't go at three quarters of the speed of light. Just keep going otherwise you're been a die old age on the way. Yeah, once the Andrews and one g Lamborghini. Let's let's talk to u Elon Musk about that, the Italian Elon Musk. All right, that's great, and so we have another how to question for you randall this one about dinosaurs and black holes. But first let's take a quick break. Alright. We're answering questions today with a super special guest, Random Row of x K c D Comics and the author of the new book How to Observe Scientific Advice for common real world Problems, And so we had a listener actually write it in with a totally relevant question for you. It's a absurd scientific question with maybe a real world solution. And so here's a question from a listener. Hi, Daniel and Jorge. My name is Chris, and I'm an avid listener from North Carolina. I've read about how scientists can resolve images of stellar objects behind galaxy clusters that have been warped and magnified due to gravitational lensing. So I started thinking about black holes and came up with this question for you. If we were someday able to build a theoretically perfect telescope, would we be able to resolve a billion year old image of ancient Earth that's been gravitationally lensed back to our telescope around a black hole half a billion light years away, where with the photons have diffused too much for an image to even be resolvable at that distance. Thanks, and keep up the great work. So that's a totally awesome question, right, Yeah, I guess the question is really sort of like, how how could we take a picture of the Earth from a long time ago? Like if we wanted to get a picture of dinosaurs or maybe the first life forms on Earth? How how can we possibly do that? Yeah, And a lot of people writing with a similar question. They ask, is the light if the light from the stars that are really far away is just arriving now, so we're seeing stars that are billion years old, if they're billion light years away, does that mean that the light from the Earth is out there somewhere so other people can see it, Right, And that's a common question, And it's true, like light from the dinosaurs is out there somewhere. Somebody a billion light years away is training their telescope on the Earth. They're seeing the Earth a billion years ago, which probably didn't have dinosaurs on it or whatever. Yeah, And I love this idea that because if you look, you know, most of the time, light goes in a straight line, unless and if you don't have a mirror, it gets bent by gravity, it steers around a little bit when it goes past a star. But if you want to make it do a U turn, you you've got to have something really really dense and really heavy, like a black hole. But like in principle, this idea is sort of it could work, you know, because when there are paths that light can take going around a black hole where it comes in and just does a U turn, skims really close to the you know, it comes kind of near the event horizon, but it doesn't quite fall in and it and it just slingshots around it and comes right back at you. Help me paint the picture here, guys. So you're saying that an image of the earth, like we're giving up photons all the time time, and those photons have an image of us, like a snapshot of of you know, when I took a shower thirty years ago, or an outdoor shower I was showing with some dinosaurs and uh, and so that light leave family podcast. I was giving some dinosaurs a shower. Yeah, my pent dinosaur um. And so that image leaves the earth. And you're saying that that image can actually come back to us and possibly we can possibly capture it right, and and the physics here, remember folks. Is, photons don't have mass, but they can be bent by gravity because gravity bend space right a curve space. And we see this all the time because because we see light bent by heavy stuff that's between us, like dark matter, stuff between us and the source of the light. Yeah, and so there are paths that the light could take around a black hole to come right back to us, and would be like looking at a mirror. If you if you could take a photo of a black hole up close, you'd see a bunch of rings of light around it, and those rings represent images of you know, other stuff around the black hole that but for the light. The light will have followed paths that loop around it, and sometimes there will be even one to three loops before it comes back to concentric rings around the black hole that represent images. But the images closer and closer to the black hole have made more and more loops around it. And so there's light that can orbit a black holes not inside the event horizon, but outside the event horizon. Is light that can essentially never leave even as though it's not inside the event horizon. Yeah, forming this this like photon sphere around the black hole. That's what you're saying, there's an image of right now, there's an image of me going around a black hole multiple times. Well, that's where we run into the practical problems here, which is that that there are these paths that light can take, but you're only giving off so many photons. There's only so much light coming off of you. You're saying, I'm not very bright. None of us are very brilliant. Yeah, no, no, we're compared to how big and empty spaces. None of us are very bright. I think that's through on a couple of levels. Um, so we're giving off photons. But like, if there were a black hole right here and we illuminated you with really bright light, you might be able to pick up an image of you around there and for you elliminute illuminated by normal, healthy natural lighting. Uh that the odds of picking up a photon came off of you and circled the black hole and came back are negligible. So you just take a picture and that you you would be represented by none of the pixels in that photo. Well, I think what happened to my photon? Like, well, let's talk about what single photon is different? Right, I mean, the question is about an image, and that's like a collection of photons that you know, get to travel around the black hole and be reconstructed looking like Jorge, but a single photon. Right, we see single photons from things a billion light years away. That's how we see stars because photons get here all right. Photons don't get like tired, they don't run out of energy right. Time is frozen for them. So a single Jorge photon could go around the black hole and come to Earth couldn't be identified easily as this one, because we need a whole bunch of or photons to see to be like, oh, hey, these form the shape of his face, you know, and then we can identify. But that takes so many that the odds of getting one of them is already slim, and the odds of getting all of them together, uh take that all take the same path, is just too low. Well, we could just pass that problem off to the engineers, right exactly, Just like I was going to say, I try to autograph all of my photons, so if you see one with my signature, that's that's you know, it's for me. So you're saying the likelihood that a photon will survive the trip to the black hole and bag is negligible because we'll hit something, you'll out because because there's the one path that would come back to Earth. If you hit just the right angle on the black hole, it'll make a loop around and come back to Earth. But for almost every other angle it'll loop around and come off in some completely different direction. It's like you're trying to It's like you're you have a basketball and you're trying to throw it another basketball across the court, but it has to hit the basketball and bounce back to your hands. And so like the odds, almost every time you try that, even if you're really good at aiming and you hit the best at ball sitting on the other side of the court, it's just gonna hit it and bounce off to the side, not even on a YouTube video. Well, with a YouTube video, you get to try so many times. Did you ask Sequila Neal to try that? I did not. UM. I had a lot of fun asking people for for advice for my book, UM, but I wasn't able to reach Mr O'Neill. But the I did actually try. I did actually try asking a radio astronomer a question that's very, very similar to this because I was thinking black holes are all so far away. It's like the basketball shot you. There's no way you could make that, you know, it's and the photons would take so long to get there and come back. You know, we wouldn't be able to get a picture of you, um and into long after we were all gone. But um, there are other objects near us that we could bounce signals off of it. And And they aren't black holes, but maybe they could be reflective. And so I talked to a radio astronomer and said, you know, are there any big clouds or something where we could send out a signal of radio waves and they would somehow resonate and bounce back, and then we could pick them up here. And because you want to watch TV from forty years ago, yeah, I was thinking that'd be a great way. You could store a bunch of data. You just put on the radio telescope, send it out and then forty years later, you know, if the thing is twenty light years away, forty years later, that data comes back to you. You didn't have to you could. That could free up your hard drive space like a radar or exactly and something to yourself. Yeah, And she said, no, there isn't There isn't anything out there beyond the Solar system like that. But we, she pointed out, we do use the Arecibo dish as a radar dish. We bounced signals off of asteroids and then pick up the reflection from them. So it's like it's not just it's not just a telescope. It's like a giant flashlight. And I think that's so cool. World's biggest flashlight. All right, So it sounds like the answer of how to take a picture of the early Earth is um with a lot of luck, that's right. Yeah, And so I think it's totally possible for those photons to go out there, come around a black hole, and come back to Earth. But practically speaking, it's going to take a really bright source and a really big mirror and a huge teles cipt tog out this photons. Cool. Al right, Randall, we have one last question for you. We're running a bit out a time, but I did this is more of a personal question, and I'm making it sound really serious, but I've thought it'd be fun to ask you that I was gonna say. I thought it'd be a fun question to ask you how to make a web comic. If you had to answer the question how to make a web comic, what would you answer? I don't know. I don't know what advice to give here, because to me it seems interesting how many people uh kind of stumbled into it by accident, Like you know, for me, I was drawing. I was drawing comics in my notebooks. I wasn't thinking about publishing them. Uh. And then I eventually went back over them and said, oh, some of these I want to put these online somewhere. Um, but I wasn't really planning. I figured that career it sounded kind of cool, but it was like not open to me because you got to know how to come up with jokes and also how to draw. And when I was a little kid, I was saying, oh, I don't know, sudden coming with jokes sounds hard, and I definitely don't know how to raw. I guess the cartooning is probably a bad career. So I was trying to do other things and then and then just stumbled into it by accident. So are other cartoonists mad that you can be so successful just drawing stick figures? Oh? I mean, I know, it's it's it's definitely it definitely saves time and hand hand vessels. But no, it's a it's a thing that that I just feel like I was I really lucked into right place, right time, you know, I was doing this and and it I feel really lucky that I've been able to make a career out of this without having to learn to draw faces, which is really hard. That's something I've always had a really hard time. But so I'm in awe of people people who can actually draw faces, you know, like like you, I always imagine that you put a lot of care and a lot of attention into each stick figure, like you think really about the post and well sure, it's like you know, if I'm drawing with like five lines, I'm gonna make those five really good, right. Yeah. And you were telling me earlier that, um, there are actually a lot of physicists who have become cartoonists, like you keep a list. Oh yeah, well, I mean it's just it's kind of surprising. You know, I think your your degrees, you know, engineering but close But Bill, are you rounding up engineering into physics? You know we're neighbors. Um yeah, no, aside from me, there's uh, you know, there's Zach Wieners Smith who does Saturday Morning Breakfast Cereal, he has a physics degree. Bill Aiman, who did Fox Trade, he also has a physics there really, um, but my favorite fact about that is that of all of the people, of all of the physics majors who got physics screes but then left physics to go into cartooning and uh, and then of those people, of the ones who were born on October seventeenth, I am not even like the most successful, because it turns out Mike Judge, who did Beavis and butt Head and Office Space, he also has a physics theree and also shares my birthday. That is wild, No, I haven't I feel like he's just like my my birthday twin rival out there. Well, there you go, folks, proof that a physics degree is guaranteed success in life, no matter what field you end up in, or maybe only cartooning, or or maybe it says that physics is such a terrible career choice and most people would rather do cartoonings. Well, you mentioned you're drawing. I have a question about that. I've noticed in a lot of your recent work you have actually really detailed and sophisticated three D drawings. Of stuff. I wonder is that something that you developed later You ever thought about like modifying or adapting your style of drawing people, or is that is your comic styles would have frozen now, you know people. People sometimes ask if I've taken a drawing class, and sometimes they ask it in a way like, oh, so did you do art school? And I'm like, what does it look like? I did art school? Sometimes they're like, have you ever thought about taking a drawing class? Like it's like, oh, thanks, but no, the only the only drawing classes I've taken. I took a few technical drawing classes for like drawing blueprints and stuff, and learned, you know, a little bit about how to do how to do those kinds of shapes for like diagrams, which I think was actually really it was helpful over comics, but almost more helpful for physics. I feel like the number of times you've had to when you're doing a physics class you have to draw a three D cube on a on a board to try to explain something like cubes are hard to draw, but like you could learn to do it. So I feel like that almost that's a drawing class that, like physicists should take because they should all learn cartooning just just basically alternative. There. I'm working on it. Well, I think that you know, all of your work and your books and your comics, they really sort of reflect your personality and your curiosity, and especially this latest book, how To, I think it really reflects that, um, you know, the mind that you have where you sort of go into deep dive on a simple question and discover all these interesting and amazing things about the universe. It's the mind of a physicist. Well, I'm really I'm really glad you enjoyed it. Yeah, and I mean that in the best possible way. Well, thanks very much for joining us on the podcast and for answering how ridiculous? How two questions? Yeah, if you're interested in getting Randall's book, just a quick reminder, it's called how To Absort. Scientific Advice for Common Real World Problems. That's right. It's out in hardcover from Riverhead and we totally recommend the you pick it up. Thank you so much. Well, thank you so much for having me on. This was a lot of fun. Before you still have a question after listening to all these explanations, please drop us the line. We'd love to hear from you. You can find us on Facebook, Twitter, and Instagram at Daniel and Jorge That's one Word, or email us at Feedback at Daniel and Jorge dot com. Thanks for listening, and remember that Daniel and Jorge Explain the Universe is a production of I Heart Radio. For more podcast from My Heart Radio, visit the I heart Radio app, Apple Podcasts, or wherever you listen to your favorite shows.