Stuff You Should Know - How Time Travel Works (Live at SD Comic-Con)

Episode Date: July 26, 2012

How does time travel work? Could it ever cross the line from science fiction into science fact? Join Josh and Chuck -- along with a live audience at the 2012 Comic-Con -- as they explore the ins and outs of time travel. Learn more about your ad-choices at https://www.iheartpodcastnetwork.comSee omnystudio.com/listener for privacy information.

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like what we would call a jack move or being robbed. They call civil acid work. Be sure to listen to the War on Drugs on the iHeart radio app, Apple Podcast, or wherever you get your podcasts. Brought to you by the reinvented 2012 Camry. It's ready, are you? Welcome to Stuff You Should Know from HowStuffWorks.com. Hey, and welcome to the podcast pre-wrap, I guess is what you call that, right Chuck? Sure. Prologue. I'll work forward. That's a good one. I'm Josh, and that's Chuck, and we are introducing a live podcast that we recorded in San Diego

just a little while ago. Wait, July 12, I think? I don't remember. I believe it was the 12th of July. It was great fun though. At Comic Con. Yeah. Yeah, it was a big deal. There were people who waited in line to get in. Some of those very people didn't get in, got turned away to see us. I know, that was weird. All those people were sorry. Yeah, for the people that came that weren't fans of the show, and if you happen to be listening now, then welcome, and thank you for coming just out of interest. That was pretty weird, you know, to see people there like, I don't know who these guys are, but it sounds interesting. Those were the 300 people who had their arms crossed in front of their chests, yeah, expectantly, and then disappointed. So we're going to just kind of get

into this. If anything seems out of place or you're freaked out by people laughing, just remember it's a recording of a live podcast. Jerry did a great job recording it, and so here's us doing time travel at Comic Con 2012. For those of you who don't know, we have a podcast called Stuff You Should Know. It's on a website called howstuffworks.com, our beloved website, and pretty soon we are going to be on the Science Channel too in January 2013, right? That's right. All right, time travel? Yeah, let's do time travel. Everybody ready to learn a little bit about time travel? We're just going to do our thing. We're recording this live. Everybody say hi to everybody who's not here.

For fans of the show, we have our producer, Jerry. It's actually here. She exists. Jerry, say hi. Jerry, if you want to say hi. Yay, Jerry. All right, brass tacks. Jerry, did you press record yet? Okay, so we are recording good. Yeah. All right, so Chuck. Josh. Have you ever heard of a guy named Andrew Basagio? I never know what to say here because I do, but should I say no? To say maybe. Maybe. Okay, so let me tell you a little bit about this guy. All right. He's a Seattle attorney. Oh, I know this guy. Okay. And ever since 2004, he's been talking publicly about how he was part of something that he says was called Project Pegasus, which was supposedly a DARPA initiative for time travel.

Yeah, the U.S. government was using children because apparently children were specifically suited for time travel, which I didn't know, more so than adults. We should say that this guy's the only source for this information. Yeah. That's kind of a big qualifier very much. But so he does have a pretty good story. Like throughout the 70s from age seven to 12, he did a lot of Lincoln assignments, I guess. He traveled to Gettysburg at one point where he was captured in a famous Josephine Cobb photograph supposedly and I went and looked and I mean, it could be him. It's really blurry photograph. There was a guy in the picture. There are several guys, but it was from 1863. So they didn't know what they were doing back then. And then he also traveled to Ford's

Theater several times, where at one point he ran into another version of himself from another time that had traveled back there for that same night. The Lincoln assassination, by the way. So, and all of this, by the way, was based on technology that was made from schematics found among the personal effects of Nikola Tesla. That's right. Who died in New York in 1943. Who knew? So supposedly the U.S. government ransacked the department, came up with this, built these time portals. Now, far be it from me to cast this version on another person's story. Chuck in my motto is to each his own. Always. Yes. We should like clink swords when we say that. I know. But I would buy this guy's story a little more if he said that he was traveling to the future.

Because after researching for this presentation, doing a little bit of time travel research, I found that there are a lot of bona fide, legitimate physicists, cosmologists who say that, yes, it is entirely possible to travel to the future. And we kind of do it every day. Yeah, it's pretty exciting. It's just, yeah, it's true. Do you want to talk about it now? Yeah, you know, Josh, there's an old joke in the scientific community, in the time travel community about a, let me see if I get this right, about an immigrant who comes to the United States. Right. Ellis Island, I imagine. And he lost his watch. It's really sad. And he goes up to a scientist and he says, please, what is time? I don't know what country that is.

That's a general, maybe European accent. Okay, he's European. And the scientist replies, I'm sorry, you'll have to ask a philosopher, I'm just a physicist. Kind of a silly joke. A good time travel. Scientists love that joke, everybody. This kills in lab rooms. But it is a silly joke, but it really gets to the heart of the matter. When you talk in time travel, it is very much a philosophical question. And it is, if time flows like a river, like some people think in one direction, the question is, can you stop that flow? Can you reverse that flow? Can you go back in time? Or can you speed up the flow and go forward in time? That's kind of the question. I find it heartening to see like physicists and philosophers getting

along, having a beer, talking about time travel, having their brains melt together. And you were talking about time flowing like a river. Can I talk about my boy Stephen Hawking? Yeah, sure. Do we have any Hawking fans in here? Same here. I love that guy. That's Josh's boy. Yeah, Hawking is my homeboy. Stephen Hawking was talking about how he wrote this really great article or essay or whatever you want to call it for the daily mail of all people about time travel. And then he talks about time as a river. He says it's very poetically, it's like a river because it flows in one direction, and we're all just kind of going

along with it. But it's also a bit like a river in that in different spots, it travels at different speeds. And if we can figure out how to exploit those different spots, then we can get to like the brass techs of time travel. Yeah, Hawking basically thinks you can travel into the future. All you have to go is really, really, really, really fast. Right. And we're talking, I think the stat is the fastest thing ever was Apollo 10. Yeah, Apollo 10. 25,000 miles an hour. Pretty fast. That's very, very fast. If you want to time travel, Hawking says you need to go 2,000 times faster than that. So that's really fast. May I interject something? Sure. I actually did the math and Hawking got his math wrong. No way. Tim, from what he goes on to say, that you need

to get very close to the speed of light, 90%, 99%. Sure. You'd have to go like 20,000 times more. Not 2,000. So I corrected Stephen Hawking and his math. And I hope he doesn't hear this because there will be a smackdown afterward, I'm sure. Be like, oh, you know math, huh? Well, one of the big problems with going that fast is fuel. In order to go that fast, you need a humongous ship that can carry fuel enough to travel. I think he said six years, like ramping it up speed-wise. Right. And that's not very likely, at least anytime soon. You would need this huge ship to go toward the speed of light, accelerating constantly for six years. And then like the fourth year, you'd start to time travel. Could you hit like 90% of the speed of light? Sure. Which is like 600

million miles an hour. Pretty fast. And then I think at that point, time goes an hour on the ship equals two hours back on Earth. Yeah. So you're starting to travel into the future relative to the Earth, right? Yeah. Then after another two years, you get to like 99% of the speed of light, which is like 660 million miles. That's when things are really happening. That's when like a day, is it a day? I think it's a day. A day on the ship equals like a year on Earth. Which, okay, that's time travel. That's very, very fast. And if you turned around and went back to Earth, you could be like, check me out. I'm from the past. Because really, this is another thing I figured out from researching this, is time travel is really, it doesn't matter if you

don't have anyone to show it off to. Yeah. Like you can go travel out and outer space as long as you want and live forever. But if no one's there to see it, who cares, you know? If a tree falls in the woods, that kind of thing. Exactly. The philosophers. Exactly. Yeah. So go ahead. Oh, you go ahead. Are we at Carl Sagan or? Yeah. Okay. That's always a great question to ask. Are we at Carl Sagan? So Carl Sagan, who's my homeboy, has a viewpoint that sort of body slams the skeptics of the world. And I know there are skeptics and skeptics like to unite and tell people things a lot with great vigor. But I am not one. I have always been more of a moulder than a scully. You know what I'm saying? That's nice. And yeah, thank you for that. And

here's what Carl Sagan has to say. Because basically what skeptics will say is, well, if you can time travel, then why aren't we always visited by time travelers all the time? Hold on. That's such a skeptic. Yeah. That's what skeptics sound like. I think we just had a skeptic leave the room. There. Done. He's gone. So Carl Sagan has this to say about. I'm going to read it because I cannot summarize it any better than he says it. He says, first of all, it might be that you can build a time machine to go into the future, but not into the past. And we don't know about it, but because we haven't yet invented that time machine. A little brain melting, but it makes sense. Secondly, it might be that time travel into the past is possible, but they haven't

gotten to our time yet. They're just really far into the future. And the further back in time you go, the more expensive it is. That one. I'm a little bit like a little bit economics into it. And then thirdly, maybe backward time travel is possible, but only up to the moment that time travel is invented. So we haven't invented it yet. So it can't come to us. We are S O L as far as time travel. So that is like, yeah, you need to be drinking something to understand that. So. No, not really. Not really. He's just saying like maybe there's like a, like you just can't go back beyond the point where time travel is invented. He's just being a rabble rouser. And the final thing he says is there's a possibility that time travel is really perfectly possible, but it requires

such a great advance in our technology that the human civilization will destroy itself before they can invent it. That's the gloom and doom one. Exactly. But in Sagan's raising all these points to say like, you know, if somebody's saying, if time travel is possible, where are all the time travelers? And he's saying, Hey, hey man, keep an open mind. That's what he used to say. And put on this turtle neck. Right. That's all just weird turtle neck. Everyone will mellow out. And I like Carl Sagan. And there was one other thing about Hawking's view. He made a good point where if you aren't a show off and you don't need to time travel just to impress your friends in the future, you could use the same ship that's going super, super fast toward the speed of light to just go

to other parts of the Milky Way. It would come in handy very much for these long distance trips. Right. So say you wanted to make it to the Orion Nebula, you could do this several thousand. Josh and Chuck, come in. Hold on. Come in. Come in. Do you hear something? Josh and Chuck, come in. This is time pilot John Hodgman speaking to you from the future. Oh, it's Hodgman. Hey, Hodgman. Hey, there you are. It's going on. 2012. Hey, Hodgman, can you hear me? Actually, you probably shouldn't be talking to me because I can't hear you. This is a time message. It only goes in one direction backwards. And I'm not even sure that I reached you. It all depends on if I got the time coordinates correct. Time coordinates, by the

way, are just latitude and longitude and altitude and time. But listen, Josh and Chuck, if you're getting this message, I need you to do something. Things have gone horribly wrong in this time stream. And it's all because of something that happens at Comic-Con 2012 that you are intimately involved with. Basically, you piss off Josh Whedon because you don't recognize him. So I urge you, look at a picture of Josh Whedon and don't piss him off because if you do, he gets so angry and he hates podcasts and then he becomes a dictator and stops making movies. But if you recognize him, I guarantee you he will make another season of Firefly. Also, Josh and Chuck, that person in the Wookie costume is not a Wookie. Okay, well, I hope that fixes everything.

It's really not good here in the future, so I hope you can fix it. I also hope that this message went to my time stream in the past and didn't get booted off to another multiverse. In which case, if this is reaching you in a different multiverse, watch out for the floating ghostly piranha. They will eat your face off. All right, I've got to go. It's all the time I have. Time pilot John Hodgman from Unnamed Future signing off. Goodbye. Hey, wow. What a guy. He is always looking out for. You never know when Future John Hodgman is going to pop in. Does anyone know what Josh Whedon looks like? Okay, we need a picture later. He's not here. Is anyone going to the Firefly panel? Oh, yeah. You better go get in line right after this. Wow. Well, that was a

Yeah, what should we do now? Should we talk about methods of time travel, maybe? Oh, yeah, go ahead. Okay. So if you're talking time travel, which we are, there are two directions you can go. Go into the future or you can go into the past. I'm a past guy. I've always liked to see the Old West. I knew you were going to say Old West. Well, I just want to be a gunslinger. Do you? Yeah. And we're fringy leathers. That's right. But if you want to advance into the future, here's what you're going to have to do. You're going to have to exploit space time, which isn't the easiest thing in the world, but it's possible. It actually happens every day up in the sky with GPS satellites. I don't know. That guy's nodding. He knows. But many of you may

not know that these satellites actually accrue an extra third of a billionth of a second every day. It doesn't sound like much, but it's time travel. It's kind of cool. And the reason this happens is time passes faster in orbit down here on Earth. Basically, Earth is like a big dopey Saint Bernard like dragging on time. And all the mass on Earth is just slowing down time and little tiny increments out there in deep space. You don't have to worry about that kind of thing. Right. And that's called gravitational time dilation. And it's a real thing. And we observe this all the time. Scientists do, astronomers do, when they see light in deep space. They'll see light moving in a straight line. And if it gets close enough to a sufficiently large object like, say, Sagittarius A, which has the

mass of four million suns, time will actually bend. And they see this and it's called the gravitational lensing effect. So if you were to, let's say, travel to Sagittarius A and circle it, this black hole, and if you don't fall in, which would be bad, actually, it might be pretty cool. No, it'd be really bad. There's a word for it, like what happens to you? S-O-L. Kind of. It's called spaghettification. Like the infinite density of the center of a black hole just thins you out into a spaghetti version of yourself that is not alive anymore. I could use that, actually. Yeah. It would be a good look. So if you were to be able to circle Sagittarius A for a little while without falling in, you would experience time at half the rate

on Earth, which is time travel. Again, you come back to Earth and you show off for everybody. Yeah. And that's basically the center of this Sagittarius A is a really super dense point. It's called a singularity, but don't confuse that with the singularity. Two very different things. That's another big future problem. Yeah. I'll be in big trouble with the singularity. Can I throw out some of my favorite, please, universal cosmic anomalies? So Chuck was talking about a black hole. One of my favorites is called a care ring or a cure ring. We can't figure out how you say it. Honestly, we looked. We really looked. So probably for the rest of the time when I say it, I'm going to say, cure ring or care ring, okay? Sure.

Okay. And basically, this is like a black hole that forms from a lot of neutron stars that have collapsed. And neutron stars are about the size of Manhattan, but they have like the mass of our sun. So they're super dense. Yeah. And a bunch of them will form into this ring that kind of turns into this whirlpool. And because of the centrifugal force of these things, there, a singularity doesn't form. Hence, spaghettification doesn't befall you when you go through the center of these things. That's right. But it's still a black hole, right? Yeah. They think that if you go through, though, it's a one-way ticket because probably on the other side is what's called a white hole, which is the opposite of a black hole. And it pushes

light and matter out away from it. So there's no way of getting back. But it's still possible that you can travel through time, at the very least to another part of space. Yeah. Right? Right. So. You want me to tell you about another one? Well, this next one is my favorite. Oh, the, yeah, the Einstein-Rosenbridge. That's right. Which, yes. Wow, that got a plus. Yeah. And here comes the rest, also known as a wormhole. Yeah. Yeah. But everyone calls it a wormhole because, like, you couldn't have a TV show called Through the Einstein-Rosenbridge with Morgan Freeman. I guess you could, but through the wormhole with Morgan Freeman is, like, catchy. Right. It's sexy. It is. Very sexy. Super sexy. So an Einstein-Rosenbridge or a wormhole, it's kind of actually

easy to grasp. If you consider time or space, spacetime, it's like a flat sheet that you fold it in half and you left some space in between, right? Yeah. Actually, you have a sheet if you want to demonstrate. Do you? I like this. Okay. And then gravity's pushing toward the center, toward this empty space in the middle. So if you have the sheet like that and you put, like, a baseball on either side, these depressions are going to form that are kind of akin to the bending of time, time dilation, gravitational time dilation. Yeah, same thing. And if the depressions that they form connect, you've got a wormhole. Boom. Yeah. And you may be able to travel through this. No one knows for certain,

but it's just kind of like the physicists are at the point now where they're like, oh, and there's also this other weird thing, and maybe you can travel through time and that. Is that what they say? That's kind of what they say. But, so Chuck is an old West kind of time travel guy. I like time travel in the past too. I tend to think that time travel, the future, is the one we're going to accomplish first. Yeah, I think so too. But the reason most physicists poo poo the idea of traveling back in time is because paradoxes arise. Yeah. And when a paradox arises, usually that means like the point is moot, like you can't argue it any further with a learned person. Yeah, we, this is the point where we talk about something called causality.

And everything we know here on planet Earth, as I say, is based on, in a time sense, is based on cause and effect. Right. And it's a one-way street. Something happens first, and that leads to something that happens after. You can't have something, you can't have an effect without the cause. Right. And it's a one-way street going then in that direction, cause effect, cause effect, cause effect. Right. It's causality. And you have one of the big, great, famous paradoxes is the grandfather paradox, right? The status of all paradoxes. Which it kind of demonstrates. Yeah, this bums chuck out because the grandfather is like, it's like, what the grandfather do, you know? But say that you went back to kill your grandfather, right? You're an assassin. Maybe you'll do

anything for money. A looper, if you will. And you go back and you walk up to your grandfather and you shoot him and kill him dead. But this is the version of your grandfather before he's conceived your father. Therefore, you can't possibly exist. Therefore, how could you get back to time travel in the first place to kill yourself? Yeah, that's so sad. It is sad. But you know what's even sadder? What? The grandmother paradox. That's where you go back and they couldn't call it. They tried it and they were like, go back and kill your grandmother. Are you serious? They're like, can you just call the grandfather at least? Because maybe he hit you once or something. At the very least, he made you mow the lawn for a nickel or something. Yeah, the grandmother just coddles you and feeds

you. Sure. Chicken and pie. Sure. At least mine did. You miss Granny Bryant, don't you? I do. Although she lived to be a hundred. I know. That's a ripe old age. That's a ripe old age. That's called a sidebar. There's also, so that's an inconsistent causal loop. My favorite is the consistent causal loop. Yeah, this is pretty cool because it's paradox free, which means it can actually happen. And there's a physicist named Paul Davies who describes it like this. Let's say a math professor travels into the future and steals this really valuable math theorem. Then he goes back to the past and he gives that theorem to a student, and that student ends up growing up to be the very person he stole it from. Everyone's going, ah. Pretty awesome. No one dies, paradox free.

My favorite example of this, though, is, well, we have a special guest here named Brian who's going to help us with this. Brian, come on up here. Brian, everybody, give Brian a round of applause. So this is Brian. He's going to read to us an example, an explanation of probably the coolest example of a consistent causal loop. Yeah. So Brian, will you take it away? Sure. Probably the best demonstration of a consistent causal loop is found in the film Back to the Future. Toward the end of the movie, Marty McFly performs Johnny B. Good on his guitar during the enchantment under the sea dance. His playing catches the attention of one Marvin Berry, cousin of the famed musician Chuck Berry. His interest peaked, Marvin calls Chuck Berry to

alert him to this unusual sound, which prompts, we must assume, Chuck Berry to write and record Johnny B. Good. But since he is from the future, we must assume that Marty McFly learned to play the song Johnny B. Good in his own time, based on a song recorded by Chuck Berry years in the past. This is impossible, however, because it was Marty McFly's performance of Johnny B. Good that prompted its creation. This paradox, where the origination of a thing comes as the result of time travel, violates the law of causality, a truly important law indeed. It's true that we could have also cited the pocket watch in the Christopher Reeve movie Somewhere in Time as an example, but Back to the Future was a way better movie. Thank you very much, Brian. Nicely done.

Thank you. Well done, sir. And then the final possibility is my favorite one, which is many worlds, parallel universes. You can time, I saw some head nods, people love that one, because you can time travel all over the place, man, and you're just creating separate timelines, and you're in many different sandboxes, and it just doesn't even matter. Right, because if you go back and kill your grandfather in another version of the universe where you weren't born, who cares? Who cares, man? Because I'll just go on another timeline. Why are you talking like that? Because that's what the hippies like, man. I got some. Do you want to sum it? I guess in summation, you know, we certainly don't know if it's for sure possible, but I think it's important to ask

these questions. You know, people like Stephen Hawking and Carl Sagan and six-century philosophers are talking about slowing down time and speeding up time, and it's worthwhile to me. Agreed, and that is our presentation on time travel. Thanks. So I think we're about out of time unless we have a few minutes for Q&A. Do we? One question? Let's do one question. Let's do two questions. You had your hand up first. There's a microphone right there. Nice. Rocket. Have either of you ever wanted to be on Celebrity Jeopardy so you could just smoke them? I would love to be on Jeopardy. I don't know if we qualify for Celebrity Jeopardy yet. Maybe College Jeopardy. But I used to sit around in college all the time and play

with my roommates and did pretty well, I thought. I think that the X factor is whether or not you freeze on TV. One more? One more? Bam. In the hat in the back? Baseball hat? Yeah, you. Yeah, yeah. You forgot. Hello. Question. Are you guys going to like do books? Like, you know how you had the little books and all this stuff? Are you going to like release those eventually? Or do you plan on it? We have two audio books, which are like books, but they're way easier than regular books. But yeah, that's definitely, we've definitely talked about that before. Like, we're still trying to figure out what the idea would be behind it. But yes, we are definitely not opposed to that. So look for it in like 2015 maybe. Yes, we get all time job there right now. Exactly. So let's see. If you

want to get in touch with us, you can tweet to us on syskpodcast. You can visit us on facebook.com. And you can always send us a good old fashioned email by wrapping it up, spanking it on the bottom and sending it off to stuffpodcastatdiscovery.com. Thanks. Have a good day. Thank you very much, everybody. For more on this and thousands of other topics, visit howstuffworks.com. Brought to you by the reinvented 2012 Camry. It's ready. Are you? Thank you. The War on Drugs is the excuse our government uses to get away with absolutely insane stuff. Stuff that'll piss you off. The cops, are they just like looting? Are they just like pillaging? They just have way better names for what they call like what we would call a jack

move or being robbed. They call civil acid. Be sure to listen to the War on Drugs on the iHeart Radio App, Apple Podcast or wherever you get your podcasts. Welcome to Crash Course, a podcast about business, political and social disruption and what we can learn from it. I'm Tim O'Brien. Every week on Crash Course, I'm going to bring listeners directly into the arenas where epic upheavals occur. And I'm going to explore the lessons we can learn when creativity and ambition collide with competition and power. Listen to Crash Course every Tuesday on the iHeart Radio App, Apple Podcasts or wherever you get your podcasts.