Time for a Definition


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What exactly is time? Why is time difficult to define? How did Einstein define time? Learn more about time as Jonathan, Lauren and Joe nail down the interpretations, descriptions and definitions of this notoriously difficult-to-define concept.

Male Announcer: Brought to you by Toyota. "Let's go places."

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 here by my cohosts. They are second to none. Could you introduce yourselves?

Lauren Vogelbaum: Not after that!

Jonathan Strickland: Come on!

Lauren Vogelbaum: Hi, I'm Lauren Vogelbaum.

Joe McCormick: I'm Joe McCormick here with our cohost Punny Booboo.

Jonathan Strickland: Thank you. Thank you.

Lauren Vogelbaum: Oh no! Okay.

Jonathan Strickland: We're talking about time today. And what is time? And why is it difficult to really explain what time is? And why are we doing a podcast about it anyway?

Joe McCormick: Well, hey, you all. I wanna ask you a question.

Jonathan Strickland: Sure.

Lauren Vogelbaum: Okay.

Joe McCormick: Now, just put your thinking helmets on here.

Jonathan Strickland: All right. Will do.

Joe McCormick: And don't get hurt. Before a second passes, half a second has to pass, - right?

Jonathan Strickland: Yes.

Lauren Vogelbaum: Sure.

Jonathan Strickland: Two of them, actually.

Joe McCormick: Yeah, it cannot pass until a half a second is passed.

Jonathan Strickland: Right.

Joe McCormick: But, before half of that second passes, a quarter of the second has to pass.

Jonathan Strickland: Yes. Two of them, in fact.

Joe McCormick: Right. And so you can't get to a half of second until the quarter is passed.

Jonathan Strickland: Right. Right. Sure.

Joe McCormick: Let's repeat this process. How does time ever pass?

Jonathan Strickland: Halving down the amount of time, saying like -

Lauren Vogelbaum: So we're asking what the smallest unit, what the quantum particle of time is.

Jonathan Strickland: Yeah, you kind of have to.

Joe McCormick: Or is there one?

Jonathan Strickland: Well, for instance, we all remember - well, maybe you don't. I remember from my days in the physical science classes in elementary school, being told that the atom was the basic building block of matter and that that was essentially as small as you could go.

Joe McCormick: Yeah, they were lying to children.

Jonathan Strickland: Even at that time they knew! I mean it's not like we discovered subatomic particles - I'm not that old!

Joe McCormick: They didn't want to pollute your innocent little brain with the idea of quarks and hadrons.

Jonathan Strickland: Yeah, and bosons and things of that nature. Yeah, they just didn't want me to really understand particle physics.

Joe McCormick: It would be like learning that Santa Claus isn't real.

Jonathan Strickland: What!? Joe, come on, man.

Lauren Vogelbaum: Particle physics is like learning that Santa Claus is real, personally. But anyway.

Jonathan Strickland: But, anyway, the point is -

Joe McCormick: It's like seeing Santa Claus.

Lauren Vogelbaum: Magic is possible, kids!

Jonathan Strickland: The point being that you learn that you can divide things into ever smaller amounts but there has to, at some point, be -

Lauren Vogelbaum: - be a bottom level.

Jonathan Strickland: Yeah, a bottom level, - right?

Joe McCormick: That's why people are coming up with strings and stuff like that.

Jonathan Strickland: Like string theory, sure. And so, theoretically, based upon our understanding of the universe as it stands right now, the standard model of the universe, we consider the smallest theoretically measurable length to be the Planck distance.

Joe McCormick: The what distance?

Jonathan Strickland: Planck. Planck length, - all right? So Planck length is, in theory, the smallest measurable distance that we would ever be able to measure. This is assuming that we were ever able to build a measuring device precise enough to measure a Planck.

There is nothing that we have remotely capable of measuring a distance that small, but the idea is that you could not measure anything smaller than that ever. It's the smallest distance possible.

Joe McCormick: The Planck distance you're talking about?

Jonathan Strickland: Yes.

Joe McCormick: Let's break this down, the physics. So the Planck distance, yeah, - it's the shortest distance, I believe, if I'm correct, that makes any sense in the standard model of physics. Going shorter, the math doesn't work.

Jonathan Strickland: Right. Our model breaks down. It doesn't fit anymore.

Joe McCormick: So what is Planck time? How does that relate to Planck distance?

Jonathan Strickland: Planck time is the amount of time it would take a photon to travel across Planck distance at the speed of light?

Lauren Vogelbaum: Okay. So what's Planck distance?

Jonathan Strickland: Essentially it's like 1.6 times 10-35 meters.

Lauren Vogelbaum: Okay, cool! I totally got that. I run into that kind of figure all the time.

Joe McCormick: It makes these huge orders of magnitude smaller than anything we could detect in any way.

Jonathan Strickland: Right. It would make a nanometer seem enormous by comparison, - right? And a nanometer is one billionth of a meter.

Joe McCormick: And then - so you imagine something going the fastest a thing could possibly go across that distance.

Jonathan Strickland: Exactly! So that makes sense, - right? Planck time, - if you're going at the speed of light, nothing, as far as we know, according to our model of the universe, can move faster than the speed of light. So that's as fast as we could possibly go.

So as fast as we could possible go against the shortest distance we could possibly go, therefor must be the shortest amount of time of possible. It's the smallest unit of time.

Joe McCormick: We think.

Lauren Vogelbaum: Well, according to our essentially flawed mathematical understanding of the universe, yes.

Jonathan Strickland: But I mean that does make sense. If you're saying, "This is the fastest anything can go, and this is the smallest amount of space that's possible," then having something travel that space would have to be the smallest amount of time, by definition. Because you can't go faster and you can't be smaller, therefore that unit of time has to be the smallest unit of time possible.

Joe McCormick: Okay, so does this concept help us define time?

Jonathan Strickland: Not at all.

Joe McCormick: No?

Jonathan Strickland: No, because how do we think on that scale? It's great for math. Mathematically it's fantastic because, again, it fits our standard model of the universe, but, in any meaningful discussion, I can't come up to you, Joe, and say, "Hey! How much Planck time has passed since the last time we chatted?" That's not meaningful, - right? So we've gotta figure out another way to define time.

Joe McCormick: Good luck!

Jonathan Strickland: Um. Let's see. How did Einstein do it?

Joe McCormick: The standard story is that he basically said - and we're paraphrasing here - that time is what clocks measure, which is kind of a joke, saying -

Jonathan Strickland: It's a circular - yeah, it's a little -

Joe McCormick: It's a joke on the fact that, for some reason, we can't seem to define time in a way that doesn't include the concept of time. All our definitions are circular.

Jonathan Strickland: Right. Right. Just like a clock! Oh, I know I'd get one over you. And Lauren just shakes her head disapprovingly.

Joe McCormick: But no! There are concepts like this that are useful, but it makes them difficult to talk about, - like the old one like how do you define "quality" without invoking the idea of quality?

Lauren Vogelbaum: Right.

Jonathan Strickland: Sure. It becomes this whole - again, a circular argument.

Lauren Vogelbaum: If everything is subjective, if this thing that we experience is essentially subjective, then how do you define it?

Jonathan Strickland: Yeah. And if it's a point where none of us can easily explain how this stuff happens, - like how is time possible? For our understanding, time is something that moves in one direction. It's a sequence of events.

In fact, Newton proposed that it was just a series of moments that would stack on to one another that was standard across everything because, at that time, there was no reason to believe otherwise, - that time, as it passed on Earth is the same as time as it passes anywhere else. And it doesn't matter where you are or what you're doing; it's the sequence of events that continues on until infinity.

Lauren Vogelbaum: Yeah, because it wasn't until Einstein that we started talking about how space and time are kind of part of the same fabric and that they're fudged around by things like gravity and speed and all that fun stuff.

Joe McCormick: Well, so I've got here a pretty interesting, working - not a definition but a place to start when thinking about time. This is from a Nova transcript I've got here, and it's Peter Galison of Harvard University.

And what he says in this program is "We're always looking for things that repeat over and over again, and that repetition, that cycle of things, forms a clock."

Jonathan Strickland: I can understand that.

Joe McCormick: That all time becomes is some repetitive process.

Lauren Vogelbaum: Something we can count, like for the four seasons or the sun -

Jonathan Strickland: Or the sun seeming to come up over the horizon, - that sort of thing.

Joe McCormick: So that's interesting to me because what that seems to suggest is that, while it's not circular in that it doesn't rely on the idea of time to define time, it does make time utterly subjective. Like we have talked about in a previous episode about the physics of relativity and time being actually subjective, it's truly an experience.

Jonathan Strickland: Yeah! Like, for instance, if you lived on a different planet - if you had never lived on Earth, if you had lived on a different planet that had a different cycle, if the day/night cycle took place - maybe it's -

Lauren Vogelbaum: Mm-hmm. If the planet spun faster or rotated around the sun.

Joe McCormick: Has a lot more gravity, more mass.

Jonathan Strickland: Let's say - well, beyond that, that would all depend on the size of the planet, - right? So, anyway, let's say that it's a 20-hour day, not a 24-hour day. Your concept of a day would be different from my concept of a day.

If you were born somehow just floating in space with no actual guiding experience, then day and night would be meaningless to you entirely; you would have to track time some other way.

In fact, I kind of wonder about that. Let's say that somehow, as an experiment, you were born in the middle of space. You're just floating free there. You've got everything you need to survive, but how would you -

Joe McCormick: You're a star baby?

Jonathan Strickland: Yeah, you're in 2001. "Also sprach Zarathustra" is playing constantly in the background.

Joe McCormick: No-no! Wait! You're Zod! You're in that thing in space. What's that thing?

Jonathan Strickland: Right. The - so you're talking about you're put into the zone.

Joe McCormick: Right. Is that what - Lauren, do you know?

Lauren Vogelbaum: I have absolutely no clue.

Jonathan Strickland: Okay. Superman 2. Anyway, you're General Zod - but, see, General Zod wasn't alone. He had other people there. He could track time by the number of times his idiotic cohort -

Joe McCormick: The [inaudible] guy.

Jonathan Strickland: Yeah. How many times he grunted, - that's how he tracks time. But no-no! If you were suspended in space and you aren't on a planet, - you're not orbiting some sort of other body - how would you track time?

Lauren Vogelbaum: It would have to be something internal. If you don't have anything external around you, then you would turn to the number of time that your heart beats or the number of times that you blink etc., - just any -

Jonathan Strickland: Or, if you have an iPod there, the number of times Blink182 comes on. You have it on shuffle.

Joe McCormick: Oh. No. This is kind of interesting though.

Jonathan Strickland: What! I like that you object to my choice of band which was only based upon the idea of blinking.

Joe McCormick: I get very well what you did there, and I resent it.

Jonathan Strickland: Joe's bothered by all the small things, as it turns out.

Joe McCormick: Oh!

Lauren Vogelbaum: Oh dear.

Joe McCormick: Well, no, it's interesting if you try to look up scientific definitions of "What is a second?" in terms of science, it's some - they'll say like "It's the time it takes this atom to do this."

And it's some huge random number that they use as a constant to base that on, which, to me, is kind of one of those funny indicators that like, oh, a second is completely arbitrary.

Jonathan Strickland: Oh sure!

Joe McCormick: It's just like our day length got divided into some relatively stable -

Lauren Vogelbaum: - manageable pieces.

Joe McCormick: - manageable pieces, like hours and minutes and seconds, and that's what a second is. There's no second in the universe.

Lauren Vogelbaum: Right. Right. And our measurement of time here on Earth is all based on the oscillation of very small things. It's based on waveforms that we can more or less detect through mechanical means.

Jonathan Strickland: Sure! Like the vibration of an ion that's cooled to near absolute zero.

Lauren Vogelbaum: Yes.

Jonathan Strickland: That's what the quantum clock is based off of. The quantum clock measures time - or the way we measure time with the quantum clock is we supercool an aluminum ion to near absolute zero.

Absolute zero is a concept where we essentially have no molecular movement, - right? There's nothing moving because, really, heat, when you get down to it, is molecules moving around. And the hotter things are the more they move around, in general.

So when you're going to near absolute zero, there's almost no molecular movement. You measure the vibrations of this aluminum ion, which are at a very regular rate, and you're using a very, very precise ultraviolet laser that's doing this at an incredible frequency.

So every second it's measuring this hundreds of thousands of time in order to determine specifically how long a second is. And the idea is that, by doing that, you have the world's most accurate clock.

Lauren Vogelbaum: - which is accurate to what? 1 second for every 3.7 billion years?

Jonathan Strickland: Yeah, you're not going to worry about losing 1 for every 3.7 billion years. That's a pretty good clock.

Joe McCormick: But it's so funny because it's the most accurate possible way of measuring this utterly arbitrary quantity.

Lauren Vogelbaum: Hey!

Jonathan Strickland: Well, it's arbitrary, but it's still meaningful.

Lauren Vogelbaum: It's meaningful, and especially since your average wristwatch, which works off of a quartz crystal, is gonna lose maybe 15 seconds a month. Really high precision, expensive watches lose maybe 10 seconds a year.

Jonathan Strickland: To be fair, I would've wasted those anyway. I don't really consider them losing because what am I gonna do with those 15 seconds? Probably download another movie.

Joe McCormick: Go on a tangent on a podcast?

Jonathan Strickland: Could do that! Could do that! Maybe make a reference to another pop band.

Joe McCormick: Okay.

Jonathan Strickland: Just to watch Joe's reaction?

Joe McCormick: You can just stop.

Jonathan Strickland: Okay. Fair enough.

But, yeah, - no-no - again, we're getting back to the whole idea: Yes, it's an arbitrary amount, and, if you were to step outside the human experience, it's largely meaningless. But, inside the human experience, it's meaningful.

Just like other ways that we've tweaked time are meaningful to us in a specific context, - like Joe! There's something that we do with time every year that I know you're just dying to talk about. It's something that we introduced, oh, right around, World War I, for some reason. Why don't we talk about that?

Joe McCormick: Okay, well, I assume you're talking about Daylight Saving Time.

Jonathan Strickland: Thank you, Joe.

Joe McCormick: By the way, for all you listening, it is "saving," singular, which sounds totally wrong.

Jonathan Strickland: It doesn't stop Joe from saying "savings" every time he talks to me about this.

Joe McCormick: Yeah, we talk about Daylight Saving Time a lot. So, yeah, the story of this goes - and this is the funny part because - hey, Lauren, how did Daylight Saving Time get started? Do you know?

Lauren Vogelbaum: Uh, I think it had something to do with farmers needing extra time in the mornings to -

Joe McCormick: There you go! There you go! Farmers, - everybody thinks this. I thought this. Jonathan, didn't you think this?

Jonathan Strickland: I thought it was because our robot overlords came down and told us to switch our clocks back.

Joe McCormick: No, you're totally - everybody gets this wrong. I thought exactly - it was farmers. Farmers need extra time, - right?

Lauren Vogelbaum: Something about, yeah, stuff and farms.

Jonathan Strickland: It's not farms, - huh?

Lauren Vogelbaum: No?

Joe McCormick: No! Apparently it - well, from what I've read, Daylight Saving Time or something like it had been proposed a bunch of times by people throughout the years, but the first time it was widely implemented was during World War I when various powers on each side, - like, I think, Great Britain and Germany implemented Daylight Saving Time in order to save energy, essentially.

Jonathan Strickland: Specifically coal, back then. Coal and energy were about the same thing.

Lauren Vogelbaum: Okay, sure. Well, even candles were even pretty expensive, and I'm sure that wax was not easy to come by at the time.

Joe McCormick: Yeah. No matter what they were using, electric lights or whatever, they were burning them into the evening hours, and that was wasting energy during wartime.

Jonathan Strickland: Yeah, which you could use that energy to kill people rather than to light homes.

Lauren Vogelbaum: Which is much better. Yeah.

Jonathan Strickland: Well, during war it's kind of necessary.

Joe McCormick: At least to the people fighting the war - or maybe not fighting -

Jonathan Strickland: The people waging the war.

Lauren Vogelbaum: Right.

Joe McCormick: Waging the war, yes. They wanted that for something else.

Lauren Vogelbaum: Higher priority, sure.

Joe McCormick: So they instituted this, and, contrary to what all of us seem to think before we learned about this, farmers hated this -

Lauren Vogelbaum: Really?

Joe McCormick: - because, if you actually think about it, the farmers, - they have to get up early, and they have to do their chores. They're supposed to do their chores along with sunrise because there's a bunch of stuff - they get up early to take advantage of the daylight and because a lot of crops have to be harvested in some specific timeframe that has to do with the dew point in the morning.

Jonathan Strickland: Sure. Or caring for animals. Like the animals are accustomed to a particular cycle as well, and so your cycle, as a farmer, has to match the cycle of the crops and animals that you care for.

Joe McCormick: Right. But so some politicians come in and say, "Well, yeah! We're gonna institute Daylight Saving Time! And we're gonna steal all the light from your morning, and we're gonna put it in the evening, where we can use it better to wage war."

So the farmers, - suddenly they get up to do their morning chores, and it looks like Picasso's "Blue Period."

Jonathan Strickland: Yeah. Even if they were keeping their time to the time of the sun - because you could argue that and say: Why does the farmer even care about what the clock says?

The farmer could get up whenever the sun comes up, - which is true except that everything else is working on the clocks. So, for example, the transportation system is working from the class, and, if, as a farmer, you have to get your goods -

Lauren Vogelbaum: If he gets his crops out to somebody else, then, yeah, you miss the train and everything is terrible.

Jonathan Strickland: Exactly. That means like the train is coming an hour earlier than what it did before Daylight Saving Time was instituted. Then you have to rush. You have to get up earlier than what you would normally get up, - you know? Again, otherwise, the clock wouldn't really matter. It's because you have to deal with the outside world that it matters.

Joe McCormick: There are tons of people around the world who just give a big -

Jonathan Strickland: Thumbs down.

Joe McCormick: Yeah. Thumbs down.

Jonathan Strickland: I was seeing every gesture.

Joe McCormick: Yeah. A big thumbs down to Daylight Saving Time.

Jonathan Strickland: Yeah. Like the state of Arizona.

Joe McCormick: They're just: "Nope. We won't do it." They just say no. I think there are some Canadian provinces. Is it Saskatchewan? Now I'm gonna feel bad if I'm remembering the wrong one, but some Canadian provinces, - they're just "No." I think Russia, as a whole, - they're like, "No."

Lauren Vogelbaum: Just "no."

Jonathan Strickland: It's too cold.

Joe McCormick: "We don't do that."

Jonathan Strickland: It's too cold here. Time doesn't even pass.

Joe McCormick: Yeah.

Jonathan Strickland: It's stayed the same since 1957.

Joe McCormick: So that's funny though that, when I was a kid, I assumed Daylight Saving Time - before I got to the misconception about farmers, I think I assumed it had something to do with science, the planet, that it actually has some meaning that we must do because of physics. Like leap year, - I thought it was something like leap year.

Jonathan Strickland: Right. We have to borrow an hour at part of the year and give it back another part of the year?

Lauren Vogelbaum: Sure! That could make sense!

Jonathan Strickland: That's telling me a lot about Joe and his -

Lauren Vogelbaum: No! Child sense, - that's fine.

Jonathan Strickland: That makes sense.

Lauren Vogelbaum: Teachers lie to you when you're a kid. We've covered this.

Jonathan Strickland: Oh, yeah, we already talked about that.

Joe McCormick: Yeah. Weren't we taught that the atom was the smallest thing?

Jonathan Strickland: The atom was the smallest building block of matter, yeah. Well, this was all kind of illustrating how tricky it is to talk about time in any way that is meaningful from outside the human experience, but, then again, we all live in the human experience so what do we care?

Here's what I wanna do. I want our listeners to 1.) I want them to watch the Forward Thinking episode about time because it's amazing. Joe did a great job on that.

2.) I want you to go to the fwgthinking.com website and check that out. We've got some blog posts. We've got the video series. We've got this audio podcast. We've got lots of other stuff there.

And we want you to have a conversation with us, to talk about: What is it about the future that has you excited or confused? Maybe there's something about the future that you're just: What are we going to do in 50 years when . . . ?

We want to know those questions, and we want to open this up and have a real conversation with you guys. So we welcome you to take part in that. We are really eager to have this.

And thanks, guys, so much for listening and being a part of this so far. We're really excited, and we cannot wait to really dive into the future even deeper than we already have.

Guys, we're gonna wrap this up. It's been great! I hope you have been enjoying the podcast. Let us know! And we will 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

Topics in this Podcast: daylight saving time, standard time, time