Announcer: Welcome to Stuff From the Science Lab, from Howstuffworks.com.
Allison Loudermilk: Hey, guys, and welcome to the podcast. This is Allison Loudermilk, the science editor at Howstuffworks.com.
Robert Lamb: And this is Robert Lamb, science writer at Howstuffworks.com. This week, we are talking about time travel.
Allison Loudermilk: Yes, in two parts.
Robert Lamb: Right. We're going to tackle traveling into the past, but first, in this podcast, we're going to tackle traveling into the future, which is a pretty common element in science fiction, television shows, music, et cetera.
Allison Loudermilk: Have you ever wanted to travel into the future?
Robert Lamb: Well -
Allison Loudermilk: Aside from the very slow pace at which we're traveling into the future right now?
Robert Lamb: Yeah. I was going to actually mention that. No, I don't really want to travel in the future.
Allison Loudermilk: You wouldn't want to meet your future self, you're not curious about Robert Lamb?
Robert Lamb: No, because all sorts of horrible things happen when you meet your future self. You've seen Timecop, right? No, you haven't seen Timecop.
Allison Loudermilk: Is that with the Jean-Claude Van Damme?
Robert Lamb: Yeah, this one was Jean-Clean Van Damme. Spoiler alert, but the bad guy ends up meeting himself in the future and they scheme for a while, but then they get kicked into each other and they melt and stuff. So, no, it just doesn't look pleasant. Plus, most of the time, traveling in the future ends up going to some horrible place with robot and dystopian system of government, and the apocalypse and all.
Allison Loudermilk: Plus you have more of a Zen outlook, if I'm reading that correctly, where you like to sorta just exist more in the present. Is that true?
Robert Lamb: No. Well, I like that idea. Obviously, I'm no Zen master.
Allison Loudermilk: Robert Lamb, science writer and Zen master.
Robert Lamb: Traveling into the future I guess would be kinda cool if you could just - there's just so many problems come with it, which we'll get into here. Yeah, at the very basics though, we are all traveling into the future. That's what's happening, like, just then, I just traveled to the future a little bit. So did you.
Allison Loudermilk: It's hard not to get stuck on it in the passage of time.
Robert Lamb: Yeah, when you get down to it, it's, like, the present that we exist we don't really experience. We only think about the passing moment and, then, that one little moment, that's where we spend all this time thinking about the future, remembering the past. As it happens though, we can sorta control the speed at which we travel into the future, or at least the speed that we experience it at, thanks to a little something called relativity. Einstein has a pretty famous quote on this.
Allison Loudermilk: I love this quote. This is a great quote.
Robert Lamb: He says, "Put your hand on a hot stove for a minute and it seems like an hour. Sit with a pretty girl for an hour and it seems like a minute. That's relativity."
Allison Loudermilk: Indeed.
Robert Lamb: Yeah. I think I would argue with Einstein that it depends on the pretty girl because what if she's talking about something really boring. It also brings to mind if you - don't take this too literally because you could not, say, build a time machine by just filling it with beautiful women and having them talk at you. Likewise, you couldn't live forever by constantly burning yourself, but there are some other things that actually do have major effects on the passage of time. One of the big ones, of course, quite literally, is mass, the physical mass of something.
Allison Loudermilk: Right. Mass alters time.
Robert Lamb: Right. This is one that really kinda blows my mind a little. Global positioning satellites, they gain about a third of a billionth of a second every day. One of the contributing reasons here is that they're farther away from the earth, from it's center of mass, which drags on time and slows it down. So then there was, I think it was Stephen Hawking makes a great analogy with a great comparison with a pyramid.
One of the Great Pyramids, large center of mass, if you're standing next to that, time is going to happen slower for you than if you're standing out in the waste. Not in a sense that you could actually detect or experience, but it would be there. So to actually travel into the future in any kind of meaningful way, you would need an enormous amount of mass.
Allison Loudermilk: A black hole.
Robert Lamb: Like a black hole, yeah. You could go and do laps around it, essentially.
Allison Loudermilk: Right, right, a super massive black hole, perhaps.
Robert Lamb: Yeah. There's probably one kicking around the center of our galaxy.
Allison Loudermilk: Yeah. See, what would happen if you circled the black hole for a couple of years without falling in - that's the key part - you'd return to an earth where an entire decade had passed.
Robert Lamb: Yeah, yeah. You would experience a year; they would experience a decade. You would have aged a decade; they would have aged a century. So it seems kinda like it's - even explaining it and having read the explanations for it, it still kinda sounds like magic, but it's just physics at work. Now, of course, another interesting one is the way speed alters time.
Allison Loudermilk: This is called time dilation.
Robert Lamb: Yeah, this one's pretty snazzy. It has yet to work its way into a major movie plot. I was talking with a friend about this. We were, like, "Man, they never work time dilation into a thriller. This thing is such a slight change, but this is one that we can actually measure. All right, so time passes slower the closer you approach the speed of light. So if you had two identical clocks, you leave one at the station, you put one on a speeding train. Then at the end of that train trip, the one that remained at the station would be a billionth of a second ahead of the one that was on the train. Okay? Now, that's not a lot. Even if you spent your whole life on -
Allison Loudermilk: It's not even enough to blink.
Robert Lamb: Yeah, yeah. You couldn't get really paranoid and be, like, "That's it, I'm going to live on a speeding, a bullet train the rest of my life, and I'm going to live forever." It's not going to happen. You'd have to - if the train could maybe attain 99.999 percent light speed, which is ridiculous speed, impossible certainly with any foreseeable technology we have right now -
Allison Loudermilk: So perhaps in particle accelerators.
Robert Lamb: Yeah, yeah, well, that's true, that's true.
Allison Loudermilk: That's really not commercially available per se.
Robert Lamb: It's hard to fit in one of those.
Allison Loudermilk: Yeah. I don't have a particle accelerator in my backyard, do you?
Robert Lamb: No, but at that speed, one year would pass onboard your accelerated train for every 223 years that passed back at the train station.
Allison Loudermilk: That's pretty insane.
Robert Lamb: Yeah. So you could essentially, in a year's time, get onboard your time machine and then travel for a year, and then you would essentially travel 223 years into the future. So that's pretty fascinating. Yeah, there's actually some more evidence for this in some of our observations that we've made with particle accelerators.
Allison Loudermilk: Sure. Over at CERN they've been checking into this, right?
Robert Lamb: Uh-huh. Yeah, they have these extremely short-lived particles called pi-mesons. Ordinarily, they disintegrate after just 25 billionths of a second, but you accelerate them near light speed and they last 30 times longer.
Allison Loudermilk: Wow. That's practically a -
Robert Lamb: Practically nothing still, true, but still, it shows that - I mean, it's proof positive that this can be done. Whether it can ever be done in way that actually allows human time travel, we'll see.
Allison Loudermilk: Okay. So we get on a really fast train and that's one way we could travel into the future.
Robert Lamb: Uh-huh.
Allison Loudermilk: And by really fast, of course, we mean something approaching the speed of light, which is not really on the table now. So what about another possibility, like, wormholes, which are also going to get into in the Traveling Back In Time podcast?
Robert Lamb: Yeah. There's - yes, some physicists believe that in the quantum foam, which is this tiny, tiny environment, smallest environment in the universe, there are just constantly wormholes popping into existence linking one portion of space time with another portion of space time. Conceivably, we could sorta grab onto one of these holes before it disappears, enlarge it enough to fly, say, a spaceship through it, and wa-la, we'd come out somewhere, some when else, right.
Allison Loudermilk: Right, at another event in space time.
Robert Lamb: Yeah. Of course, that brings a number of problems with it. How do you choose which little tiny momentary hole in space time to expand? Then, how do you crawl through it?
Allison Loudermilk: How do you expand it in the first place?
Robert Lamb: Yeah and how do you not end up in some horrible hell world, just like in the movies? That's what happens in the movies is all I'm saying, so watch out. So yes, time travel into the future is possible. To the limited extent we're doing it right now, if you hop on a train or if you're listening to this on an airplane or in the car, you are experiencing it as well.
Allison Loudermilk: Perhaps that's not the answer you were looking for.
Robert Lamb: Yeah.
Allison Loudermilk: Perhaps you were looking to jet a century ahead or a few millennia ahead, and that's not really the case quite yet.
Robert Lamb: Right. Do not go stand next to a pyramid and blame us.
Allison Loudermilk: Of course, if you really love pyramids, then time might speed up, just like Einstein sitting with his pretty girl.
Robert Lamb: So on that note, do we have any listener mail to get into? I think we have a few letters sitting around here, don't we?
Allison Loudermilk: We do, we do. Do you want to read them this week?
Robert Lamb: Sure. What have we got? All right, this one comes from Callum, age 14, "Hi, Allison and Robert. I'm a new listener, but downloaded some of your back episodes of which I really liked. I'd like to bring up the episode Amazing Infestations." Do you remember that one?
Allison Loudermilk: I do. That was a fun one.
Robert Lamb: Yeah. "This isn't a complaint. I really like your podcast and all of the How Stuff Works podcasts. Admittedly, rats are classed as vermin, but they also make amazing pets. They are cute and as almost intelligent as dogs. They can swim half a mile without stopping and tread water for three hours. I've never tried this out. I have three rats, Smudge, Lizard and Cleopatra, Cleo for short, and included photos, so that you can see that rats are cute and not all vermin."
Allison Loudermilk: Cleo is my favorite.
Robert Lamb: Yeah, Cleo's pretty cute. They're all cute. All white rats. "Sorry that the photos are blurry, but the rats are fast runners. Thank you for reading this email, from," he signs it. So yeah, he included photos of all the rats, and they were cute. Certainly, that's something worth mentioning is that even though pretty much with any of these species that become a problem, a lot of it can be traced back to humans causing some imbalance in the environment.
At the very heart of things, you have a dense metropolitan area, a medieval city where everything's dirty and wretched, and there's food available, and you have an explosion of rats living in the area, but you can't blame the rats. They're just responding to the environment that humans have artificially created.
Allison Loudermilk: Well, then, also, you think about those Christmas crabs that were overrunning Easter Island. Do you remember those that we talked about those?
Robert Lamb: Uh-huh.
Allison Loudermilk: That infestation is a natural thing. It's short-lived. It happens and, admittedly, it's probably a little unsettling for your house to be overrun by Christmas crabs, but it doesn't happen for a long time.
Robert Lamb: Yeah. There's actually some - I've seen reading some stuff about the Christmas crabs claiming that it happened because of some particular species ended up being eliminated due to some other species being introduced on the island. Then there's another invasive species that's hurting the crabs now.
Allison Loudermilk: Hurting the crabs or herding the crabs? Like an Australian herding - no.
Robert Lamb: I like the idea of the herding, that would be amusing. That would be like there was an old lady who swallowed a fly. Christmas crabs are out of hand, so they bring on the wolves to herd them around, and then they have to herd the wolves. Anyway, cute rats is what I'm trying to say.
Allison Loudermilk: Yeah. We always like hearing from listeners, so thanks for writing Callum, and we hope we said your name right.
Robert Lamb: Everyone out there, be sure and check out our Facebook and Twitter accounts.
Allison Loudermilk: Sure. We're on Stuff From the Science Lab, and Lab Stuff over at Twitter.
Robert Lamb: Yeah. You can do a search, we'll show up as Lab Stuff on either one.
Allison Loudermilk: If you guys want to send us an email, we always like hearing from you. We're at Sciencestuff@howstuffworks.com.
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