What does the theory of relativity have to do with time? Why would it be hard to synchronize time between Earth and space travelers? Is it even possible to have a standard time once you leave Earth? Learn more about time with Joe, Jonathan and Lauren.
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Welcome to Forward Thinking.
Jonathan Strickland: Welcome to Forward Thinking everybody. It's time for another podcast. My name is Jonathan Strickland, and I am joined by -
Lauren Vogelbaum: Lauren Vogelbaum who is shaking her head at you.
Joe McCormick: And Joe McCormick who - I made some horrible noise when you - never mind.
Jonathan Strickland: Well, you know. I make a time joke. They both groan because we are talking about time today. And we're talking about time and relativity and sort of the challenges that we're going to have in keeping time in the future.
And you might think, "Well, I thought we got pretty good at keeping time by now. I mean we've got a long history of keeping time, centuries of keeping time." And it's true; we have gotten very good at keeping local time, particularly things like making sure that our seconds match up every single second of the day, - like, for instance, a quantum clock, which is keeping time so accurately that it won't lose a second for 3.7 billion years.
Lauren Vogelbaum: As opposed to the old standard, which is one second every hundred million years, which is just, you know, -
Jonathan Strickland: Yeah, it's unacceptable.
Lauren Vogelbaum: - unacceptable. We can't live like that.
Jonathan Strickland: Right. So, from a local perspective, we are very good at keeping time, but that local perspective is all based on the fact that we're all pretty much stuck here on this big ol' rock we call the Earth, traveling around the sun together, more or less moving at the same speed, - although, depending on where you are on Earth, that actually changes just a little bit.
But it turns out that time is not something that is universally standard, - right, Joe?
Joe McCormick: What?!
Jonathan Strickland: I didn't know this was news to you. You wrote a whole episode of Forward Thinking about time. You don't remember that?
Joe McCormick: No!
Jonathan Strickland: Maybe it was in the future. Anyway, time is not standard;
Joe McCormick: Hold on a second!
Jonathan Strickland: Yeah. All right.
Joe McCormick: So you're telling me -
Jonathan Strickland: Yeah.
Joe McCormick: You're telling me what, - that time is not a real thing? What about all of the physical laws that we think of that are based on time, like light takes this long to cross this amount of distance?
Jonathan Strickland: All right. So time is relative, Joe. Time is relative, depending upon a few things like gravity or mass or the speed at which you travel.
And, for us, for human beings, time is a very subjective experience, where we experience time the way most of us are familiar: A second takes a second. A minute is 60 second. An hour is 60 minutes.
Lauren Vogelbaum: Unless you're sitting in a doctor's office or attending a really boring lecture, in which case a second is much longer than that!
Jonathan Strickland: Or you're having fun, in which case a second is much smaller. That, of course, goes back to the subjective part.
Joe McCormick: Well, we don't even know how long a second takes for somebody else, - right?
Jonathan Strickland: Sure.
Joe McCormick: I mean I know what a second feels like to me. What if your second feels a lot longer than mine does?
Jonathan Strickland: Okay, yeah. And what if the color blue looks different to you than it does to me? That's beside the point here, Joe. What I'm trying to get at is, depending on how fast you, Joe, are traveling, time will pass at a different rate for you than it would for someone who is not traveling at that same speed.
This gets really complicated because we're technically all traveling already. We're on a planet that is moving. That planet is not stationary.
Now, if we had gone back to pre-Copernican times, where we all had just assumed the Earth is a fixed location that is static and is not moving, and, if that were in fact true, time would be a pretty simple thing for us to keep track of.
But it's not true. We are on a planet that's moving around, and that's part of what determines how times passes for us.
Now, if you, Joe, were to get into, say, - I don't know - a spaceship that has a really fast propulsion system on it, like close to the speed of light, and then you were to just do a quick joy ride around the solar system and come back.
For argument's sake, we'll say that you spent one hour, according to your experience. Your watch says one hour has passed, and you land back on earth. Now, if you were to compare your watch with my watch, which we had synchronized before you got in that spaceship, you would see that more time had passed on my watch than on your watch.
Joe McCormick: That's true, - isn't it? Yeah, so I actually did a little research on this.
Jonathan Strickland: Joe, you were pulling my leg earlier!
Joe McCormick: I'm sorry. I was faking it. I'm not that - well, okay, I'm pretty misinformed.
So I say -- what if you start watching a movie when you get on your spaceship and then somebody back on Earth starts watching a movie at the same time? How much time do you have to finish a movie if, say, you're going at 90 percent of the speed of the light.
And I looked up the Lorentz Transformation ratio on this, and it says, if you're going about 90 percent of the speed of light, the transformation effect is at a ratio of - I think it was 2.29.
And that works out that the person on the ship, who leaves in time to watch a movie, comes back when it's over, has time to watch The Little Mermaid.
Back on Earth, at the same time that the Little Mermaid viewer arrives home, you have just finished watching The Godfather, Part II, - 200 minutes long, the full thing, the sadness at the end.
Jonathan Strickland: So you get some Pacino and De Niro, while the other person's singing "Part of Your World." So, for the person on the spaceship, it feels like only 90 minutes have passed. For the person on Earth, it's much longer.
Lauren Vogelbaum: Or 90 minutes only half passed for the person on the spaceship.
Jonathan Strickland: That's true!
Lauren Vogelbaum: It doesn't feel like it, but it is.
Jonathan Strickland: Right! Because that's the way time works!
Lauren Vogelbaum: It's a subjective experience.
Joe McCormick: That's the thing, - subjective in the sense that it feels normal for everybody.
Jonathan Strickland: Right!
Joe McCormick: For you, on the spaceship, - it doesn't feel to you like your time is going any slower. Everything seems totally normal. Your watch, - the second hand takes a second to tick.
The movie looks like it's playing at a regular speed, but, if somehow the people on the Earth were able to peer in the window of your spaceship, - obviously they wouldn't be able to, but if we could just imagine that - it would seem to them like you were watching the movie in slow motion.
Jonathan Strickland: Right. And that everything was going in slow motion, - not just you watching the movie, but your watch: the second hand would be ticking away at a slower rate that it should, for that other observer.
This is also tricky because we often talk about "from a stationary observer." Well, we don't really have any stationary observers because, again, -
Joe McCormick: There's no such thing.
Jonathan Strickland: Yeah! We're on a planet! The planet's moving!
Lauren Vogelbaum: Yeah! It's a giant spaceship, essentially.
Joe McCormick: Isn't it even like just theoretically a rule that there's no such thing as a stationary observer, -
Jonathan Strickland: That's a good question!
Joe McCormick: - that you can only - you can sort of posit one, but there's no way of actually confirming that you are stationary.
Jonathan Strickland: You're technically in a universe that's expanding. So it's a complicated thing, - right? Because, if you are part of whatever system you are in, then you are moving, - right?
So this gets to be a mindbender. And you might think, "Oh, this is kind of crazy. We're talking about near-speed-of-light travel."
We have to contend with this right now. There are satellites in orbit - they're in geosynchronous orbit over the Earth - that are keeping track of things like your GPS stuff, which isn't necessarily geosynchronous orbit, but you've got satellites up there that are sending down information, and our GPS systems, which - I'm sorry. I just said "GPS system." I'll have to go to the "ATM machine" and use my pin number.
But let's say you've got a GPS, and it's getting information. It's technically getting information from multiple satellites, and that information includes when the satellite sent down a packet of information. And, by using this data, the GPS can determine where you are on the surface of the Earth. It triangulates all that data.
And one of the important things in that is that: When was the data sent by the satellite?
Joe McCormick: It's super time-sensitive!
Jonathan Strickland: Right! Exactly! Because that's how it figures out where you are on the surface of the Earth.
Lauren Vogelbaum: Mm-hmm. So those seconds matter!
Jonathan Strickland: Right! And the thing is those satellites that are in orbit are tracking time, to us, it seems like at a different rate because their clocks, over the course of a good span of time, start to lose time.
Lauren Vogelbaum: Due to the distance from the center of gravity of the Earth and due to the speed at which they're moving.
Jonathan Strickland: Yeah, they're moving faster!
Joe McCormick: To be fair, that change is so tiny.
Jonathan Strickland: It is tiny.
Joe McCormick: Like, if we were just to be aboard this satellite or something, we wouldn't even notice it. We're talking about tiny, tiny fractions of a second. Now, it matters if you're doing really precise calculations, like I assume the kind that a GPS would do.
Lauren Vogelbaum: That matters.
Jonathan Strickland: Sure.
Joe McCormick: But, at those kinds of speeds, it doesn't become a really noticeable problem the same way it was when we talked about watching The Godfather.
Jonathan Strickland: Right. That's much more - it's like an instant realization, whereas with the satellite it's an accumulative thing as well. It would take months before people would even start to notice, "Something's hinky here! I know that we synchronized them, and they're all atomic clocks! Why is this happening?"
Joe McCormick: But we have to contend with that macro-dilation reality too, - don't we? I mean, if we're talking about the future, and we're talking about expanding into space - assuming we really are going to explore the cosmos -
Jonathan Strickland: Right.
Lauren Vogelbaum: Which you know I'm going to. I don't know about the rest of humanity. Everybody else better catch up.
Jonathan Strickland: Lauren's like, "See ya!" I'll just call her Major Tom from now on.
Lauren Vogelbaum: Suckos! I'm out!
Jonathan Strickland: But, yeah, if we want to do that - for instance, if we want to try and find another planet to colonize, most of the planets that would be even remotely possible for that are hundreds of light years away.
Lauren Vogelbaum: Yeah, the nearest systems, period, are hundreds of light years away.
Jonathan Strickland: No, well, Alpha Centauri's two.
Lauren Vogelbaum: Oh, okay. It's only two. Sure. Yeah. Sorry.
Joe McCormick: I was thinking of Kepler 22b. You know that one? That was the one that the Kepler found, and they were like, "Oh! This one looks pretty cool!"
Jonathan Strickland: And it's 600 light years away.
Joe McCormick: Yeah, 600 light years away. That's light years. I mean, technically, according to relativity, you cannot travel at that speed.
Jonathan Strickland: Right.
Joe McCormick: You can't go at light speed. The closest we can hope to do, if we accept the universal speed limit of light speed, is getting close to light speed. Like we were talking about earlier, it's possible maybe we could someday get a craft that goes 90 percent of the speed of light. And then traveling to these places becomes a lot more feasible.
Jonathan Strickland: Right. But you're still talking about the descendants of the people who got on board the ship are the ones who are there.
Lauren Vogelbaum: Or some kind of cryogenic sort of shenanigans or -
Jonathan Strickland: Or we manage to find some way of turning off the aging gene so we're perpetually the same age as whenever we got that treatment done. I wish that they would hurry up with that because my time is running out, people.
Lauren Vogelbaum: I've heard you're very old, Jonathan.
Jonathan Strickland: That's what I hear!
Joe McCormick: Lauren, I don't trust the cryogenic freezing, by the way, because, every time you do that, mother wakes you up halfway there, and there's some beacon you've gotta go check out on some weird blasted rock in the middle of space.
Jonathan Strickland: This kind of brings me to mind of another science fiction - a beloved science fiction franchise, and I'm talking specifically about Star Trek, where they've established the idea of the "star date."
Joe McCormick: [makes buzzer sound]
Jonathan Strickland: Right. "Star date" is essentially - well, I guess they do it in quadrants in Star Trek. But they have an established time that everyone can magically work on, and that way, when you refer to a star date, everyone else that you encounter knows exactly what time you're talking about because they're all keeping that same star date somehow.
Lauren Vogelbaum: Right. I can only assume that they either have a computer on some planet - probably Earth because Earth is clearly the center of the entire universe - or something else that is keeping time and is so technologically advanced that it seems like magic to us, transmitting that signal simultaneously to every clock in the rest of the universe, or I don't know, - that quantum logic has advanced to a state that the computers can handle the logarithms.
Jonathan Strickland: Maybe they've got the entangled electrons, and the spin of the electrons tells the onboard ship clock, "Okay, yeah. Ship time" - because you would have to have ship time.
Joe McCormick: Oh, of course!
Jonathan Strickland: Ship time would be what it would feel like to the people who are on board the ship, - right? And that time would feel like just like on any other surface: A second is a second. A minute is a minute, etc.
The star date is supposed to be outside of that. It's supposed to be this universal time. And, again, I agree. I think it's probably something that's supposed to be set on Earth because Star Fleet is where Earth is, and I can't believe we're having this conversation this in depth.
Joe McCormick: They didn't even keep it consistent on the show.
Jonathan Strickland: No. The early days they just had it as shorthand. Back before, like the first - if you watch the original series and you watch those first few episodes, they aren't consistent. In fact, there are later episodes that have earlier star dates because they were just kind of - they thought it sounded cool.
Lauren Vogelbaum: They were just spitting out numbers.
Jonathan Strickland: Yeah.
Lauren Vogelbaum: They were like number 47-47-47, etc. I noticed, yeah.
Joe McCormick: Yeah, that is a cool number!
Lauren Vogelbaum: And, in the Star Trek universe, 47 is pretty big.
Jonathan Strickland: But, anyway, that's the thing is that you would have to have some sort of really complex computer to be able to take in that information and take your on board ship's clock, and it's just ridiculous.
Joe McCormick: Wait a second. Let's break this down.
Jonathan Strickland: Okay.
Joe McCormick: Let's talk about what's really the problem here. Okay, now in Star Trek, they're going faster than the speed of light.
Jonathan Strickland: Yeah, their warp speed.
Lauren Vogelbaum: Frequently, yeah.
Joe McCormick: Maybe that's possible. Maybe everything we know is wrong, but let's just say that, for right now, that that's not actually what we're gonna be doing.
Jonathan Strickland: Okay. That's fair enough.
Lauren Vogelbaum: Okay. We'll just ignore tesseracts entirely. Just skip over that. That's cool.
Joe McCormick: Let's imagine that we can go 90 percent the speed of light, light we were talking about before. Break it down. What's the actual problem? Why can't we keep clocks synchronized?
Jonathan Strickland: Well, because, again, time is - from a stationary observers, which, again -
Lauren Vogelbaum: From the observer down here, time is literally moving differently. It's all the Theory of Relativity by Einstein that says that time is part of the fabric of space and that the fabric of space/time is warped by both gravity and speed. And so you are changing - you are intrinsically changing the nature of this imaginary thing.
Joe McCormick: You're changing your experience. It sounds like essentially what we're saying is that time is an experience. It's not something that you can track in any kind of standard or universal way.
Jonathan Strickland: It's also a magazine.
Joe McCormick: Yeah.
Jonathan Strickland: I just didn't want you to pigeon-hole yourself.
Joe McCormick: It's also a Prince side project.
Jonathan Strickland: That's true. Yeah. Morris Day?
Joe McCormick: Uh-huh. Yeah.
Jonathan Strickland: Anyway, yeah, that's - Joe and I are bonding over terrible references.
Yeah, I mean it's totally subjective, and, really, to me, one of the interesting things is that, from the perspective of any one individual, whether that person is aboard a spaceship or on a planet or drifting off into the dark, cold clutches of space itself, time is passing at a normal rate, - normal being "this is what I'm used to."
Lauren Vogelbaum: To that person, right.
Jonathan Strickland: It's not until you meet up with someone else who's been traveling at a different speed and you compare notes that you even have the moment where you're like, "Wow! That's weird!"
Joe McCormick: So maybe we would just have to give up the fact that, okay, if you're traveling at a very significant fraction of the speed of light, everything's gonna get messed up. Actually, no matter how fast you're traveling, it's gonna get messed up a little bit.
Jonathan Strickland: Right. It's just a question of: The faster you travel, the more messed up it gets.
Joe McCormick: Right. In an exponential way.
Jonathan Strickland: Yes.
Joe McCormick: Okay. So we understand that traveling in these spaceships at a near fraction of the speed of the light will make keeping track of time across distances completely pointless. You just can't really do it.
Maybe you could, I'd imagine, have different sort of galactic time zones, - like each planet keeps its own time or each solar system keeps its own time in a way that is useful locally. And, when you get somewhere new, you just have to adapt to their time.
But that introduces another idea to me: So, if we're traveling beyond Earth, aren't we gonna get messed up real bad? Just our bodies, our brains, - we are so deeply programed to work on this planet that has an essentially 24-hour day.
Lauren Vogelbaum: A particular Circadian -
Joe McCormick: Right. What happens to us when suddenly we just do not have day and night anymore?
Jonathan Strickland: Well, if you're aboard the ship, I assume - I mean we're talking about far enough in the future where we have these propulsion systems. It's far enough to say that I think we would be able to simulate night/day cycles aboard the ship.
So, at least on ship, your night/day cycles, to you, would seem normal. They would seem to be transpiring at the same rate as they would if you were back on Earth.
Now, meanwhile, back on Earth, if they were able to see what your night/day cycles look like, they would say, "Wow. That's nothing like what it is on Earth." Because, again, you're traveling at near the speed of light.
So that's - from the two different perspectives, it's gonna seem totally different, but, for each individual, it's gonna seem perfectly normal. That would allow you to at least maintain some sense of balance from a normal day/night cycle while you're on the ship.
On another planet, totally different story, - you're pretty much - unless you're living inside all the time with no windows out to the outside world, -
Lauren Vogelbaum: Or you're on a planet that as a day/night cycle that's so near to Earth's that it doesn't really matter anyway.
Joe McCormick: Like Mars, - Mars is really close.
Lauren Vogelbaum: Like 23-something-something hours or something.
Jonathan Strickland: Yeah, it's very similar. It's similar enough where I think it would be fairly easy to adapt to the day/night cycle, - not a whole lot to see outside on Mars though. You'd be like, "Is it a nice day? Well, it's kind of the same."
Lauren Vogelbaum: "It's red and dusty. It's kind of dusty."
Jonathan Strickland: "It's a little less rusty than it was yesterday. It's not true. It's all oxidized." Yeah, so that's just -
Joe McCormick: What does night even look like on Mars? I feel like all the pictures I've seen were taken during the day.
Jonathan Strickland: Well, at night it's pretty dark. They don't have any street lamps out there.
All right. You know, guys? This is incredibly interesting conversation, but, as it turns out, it's going to be really hard if not impossible to manage time across both Earth and interstellar traveling spaceships that are moving at near the speed of light or really any significant speed, - significant enough to get out of our solar system and perhaps into another one, just because that's the way time works.
And it's pretty hard to wrap your head around. It's weird to think that the second hand on my watch would be moving, to me, the same amount that it would on Earth, if I were on a really fast ship, but, from an outside observer who is somehow magically able to see this, it would look like it's moving in slow motion.
That seems crazy and counterintuitive to us, but that's the way time works. I actually don't wear a watch so I don't even know why I bothered doing this show.
Lauren Vogelbaum: Yeah. Me neither. Are we three non-wearers right now?
Joe McCormick: Oh yeah.
Lauren Vogelbaum: Excellent!
Jonathan Strickland: Oh wow!
Joe McCormick: I just got a lot of hair on my wrist.
Jonathan Strickland: So, as the great Douglas Adams once said, "Time is an illusion, - lunchtime doubly so." And I think that pretty much sums it up, guys.
We here at Forward Thinking are really excited to have a conversation with you, our audience, and to really make this an interactive experience, - not just us gathering around and chatting into microphones and being silly, but to really have conversations about the future and things that are going to play a role in our future.
So we highly recommend you go check out the website. It's fwthinking.com.
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And we look forward to having a conversation with you and finding out what you think about the future and what gets you excited. Let us know, and we'll talk to you again really soon!
Male Announcer: For more on this topic and the future of technology, visit fwthinking.com.
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Duration: 21 minutes