Daniel and Kelly’s Extraordinary Universe - What's the fastest event ever measured?

Episode Date: August 13, 2024

Daniel and Jorge slice time down to its shortest slivers to understand how fast things can happen in the Universe.See omnystudio.com/listener for privacy information.

This is an I-Heart podcast. December 29th, 1975, LaGuardia Airport. The holiday rush, parents hauling luggage, kids gripping their new Christmas toys. Then, everything changed. There's been a bombing at the TWA terminal. Just a chaotic, chaotic scene. In its wake, a new kind of enemy emerged, terrorism. Listen to the new season of Law and Order Criminal Justice System

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Hold up. Isn't that against school policy? That seems inappropriate. Maybe find out how it ends by listening to the OK Storytime podcast and the IHeart Radio app, Apple Podcasts, or wherever you get your podcasts. Get fired up, y'all. Season two of Good Game with Sarah Spain is underway. We just welcomed one of my favorite people, an incomparable soccer icon, Megan Rapino, to the show. And we had a blast. Take a listen. Sue and I were like riding the line. Bikes the other day, and we're like, we're like, people ride bikes because it's fun. We got more incredible guests like Megan in store, plus news of the day and more.

So make sure you listen to Good Game with Sarah Spain on the IHeart Radio app, Apple Podcasts, or wherever you get your podcasts. Brought to you by Novartis, founding partner of IHeart Women's Sports Network. If a baby is giggling in the back seat, they're probably happy. If a baby is crying in the back seat, they're probably hungry. But if a baby is sleeping in the back seat, will you remember they're even there? When you're distracted, stressed, or not usually the one who drives them, the chances of forgetting them in the back seat are much higher. It can happen to anyone.

Parked cars get hot fast and can be deadly. So get in the habit of checking the back seat when you leave. The message from NHTSA and the ad council. Hey, Jorge, do you think our podcast episodes are getting like a little too long? Are they longer than it used to be? You know, we used to start out around 40-ish minutes and some of the recent ones have been hitting an hour. Ooh, but not the ones with me in it, right? I just try to keep it short.

You ask a lot of questions and sometimes it takes an hour to explain them all. I guess we are trying to explain the whole universe, so that's supposed to take a while. Yeah, it's actually amazing if you can explain like a whole year's worth of. physics in like 60 minutes yeah and the funny thing is that I usually forget it within 60 seconds that's where you got to listen to it 60 times but then I'll give it 160 of the attention it needs so hey we're done after an hour right I think the math works out yeah yeah yeah I do pay attention to math Hi, I'm Jorge, I'm a cartoonist and the author of Oliver's Great Big Universe.

Hi, I'm Daniel. I'm a particle physicist and a professor at UC Irvine, and I'm very conscious of our finite amount of time. You mean like here on Earth or on the air? Yeah, both, absolutely. We're spending a non-trivial amount of time on Earth on the air now that we've done so many episodes. You know, it's like a non-zero fraction of our lives we spent doing this podcast. Yeah, I know. But, you know, more existentially, my kids are growing up and going to leave home soon. And so, yeah, I'm valuing every hour I have with them. Yeah, they grow up pretty fast, sometimes too fast.

Do you believe in parental time dilation? Everybody says, oh, those years go by so fast. But, you know, when you have a screaming toddler and it's two in the morning, it feels like about a million hours before they go down for their Definitely time seems to go by faster, but I feel like I've, you know, paid attention pretty good. There's definitely a lot of video records of our children. So we can always go back down memory lane. Yeah, that's true. But anyways, welcome to our podcast, Daniel and Jorge Explain the Universe, a production of IHeartRadio.

In which we try to take an hour to slow down and really understand something. We think it's worthwhile to update the mental model in your mind. It's explaining the way the universe works out there. We wanted to correspond as much as possible to the way the universe actually works. The weird rules that quantum particles follow, the incredible powerful forces swirling at the hearts of black holes. We want your brain to be aligned with the universe, even if it does take a little bit of time.

Yeah, we do like to take our time to make the most of your time when it's time to understand the universe. And the universe operates on so many amazingly different time scales. We think about our lives in, you know, tens of years, maybe 100, if we're lucky. But that's just the blink of an eye in the history of the universe that is billions of years old. And then also between every second, there's an incredible number of quantum operations happening. Electrons buzzing and towing and throwing and particles appearing and disappearing. Things happen in the universe from the tiniest fractions of a second all the way out to billions and maybe even trillions of years.

Yeah, there's a lot going on in the universe. and time seems to be underneath it all, dictating at what rate things happen and in what order things happen. And I wonder sometimes whether the deepest answers to the nature of the universe are at the shortest time scales, like what is the real fabric of reality,

the smallest bits and the smallest pieces of time, dictating how everything else works, somehow bubbling up to form our universe, or whether the real story is of the longest time periods, what's happening to the universe, how does it form, what is its future, over billions or maybe trillions of years. You know, the billions of years that our universe has existed

could just be the first few moments of a much longer, impossibly to imagine deep time future. Do you feel like maybe you have a little bit of a fear of missing out in the universe? You know, that maybe things are happening too fast for you to notice or too long for you to live through? Yeah, I have FOMU, a fear of missing the universe for sure. Yeah. physical fear of missing the universe.

Fifomu. Yeah, some of the most interesting things that happen in the universe are not the tiniest rules of the little particles, but how things come together over time. You know, galaxies took hundreds of millions of years to form. Imagine you were an intelligent species that existed somehow in the first 100 million years in the universe. You would never even see a galaxy,

which to us now is like the basic building block of what's out there in space. What if the most basic building block of the future hasn't yet formed an intelligent species that evolve in a trillion years will wonder about what it was like to be us never even seeing the most basic thing that exists in their universe? Or even if the future is said at all. Yeah. Right? Isn't there a big question of whether the universe is deterministic, meaning you can sort of know what's going to happen in the future or at least in one of the futures or whether it's totally random? that's right and we're hoping to push ourselves into a future where we understand the universe a little bit better from the largest time scales to the shortest time scales yeah and when it's time to do that we will take a little bit of time to explain it to you in hopefully more or less an hour because time seems to be one of the most fundamental things in the universe but sometimes you have to ask questions about time itself and while we can't see the deep future yet we can do our best to try to understand the shortest time scales to zoom in on the how fast things are happening in the universe.

So today on the podcast, we'll be tackling. What's the fastest event ever measured? You know, when people run simulations, like the hearts of neutron stars or like weather or whatever, they always have to choose like a minimum time step. Now, you have your universe and then you evolve it forward in time, one step in time. And then again and again and again, and eventually you describe something longer. but there's that minimum time. On the computer, right?

Yeah, on the computer when you run simulations. And so in our real universe, I think it's fascinating to think about, like, well, what is the shortest time step? How far have we, like, zoomed in to see, like, the fastest thing ever happened? Yeah, or possibly we are living in a simulation, right? Isn't that something that even smart people think about, not just conspiracy theorists? I think it's definitely true that smart people think about it. I don't know how true it is that smart people believe in it or think that it's realistic. I know there's a lot of talk out there about it.

It's a lot of fun to think about. But if you had to ask people like whether they really believed it, I mean, I think it's unlikely we're living in a simulation, for example. You mean it's fun to simulate in your head? That maybe we're living in a simulation? Yeah, it's a really clever sort of meta idea. Like we think about simulations as you say, we run simulations in our head,

we use simulations for science. We had a whole fun podcast episode about the importance of doing simulations in science. It's really a whole new branch of science sort of different from experimental and theoretical physics you know we describe things like in vivo or in vitro and now sometimes we call them in silico but i don't know that we actually are living in a simulation or you know how we would actually prove that but we have a whole episode about that so folks interested in that go check out that episode right right but whether it's a simulation or

not there's definitely time in it and as you said when we create little universes in our computers you have to pick a time step to do your simulation in and so you can kind of ask the question, does that happen in the real universe as well? Yeah. And when we do it in our simulations, we pick a time step short enough that we're not ignoring anything important. So we try to figure out, like, what is the shortest time step we're interested in? You know, if you're simulating like a evolution of a galaxy, nothing really exciting happens

in a year or a hundred years. So you might take like a thousand year time steps. But if you're simulating like a nuclear explosion underground, you might take time steps with like a millionth of a second to make sure you're capturing all of the dynamic. Yeah. And as you said, there's lots of things happening in the universe. And the idea of a time step is also important when you try to measure things, right? Yeah. Like if you try to measure an explosion, you don't want to sample the explosion every three minutes because it's going to be gone and over. And when you're sampling, you know, the motion of a star, you don't want to do it every femtosecond because you're going to have too much data. Yeah, exactly. So things happen on different time scales. And the question is like, what's the fastest thing we've ever measured? And what's the actual minimum time slice over? the universe. Hmm. Two big questions about very small things.

Hopefully, we can do it in the short amount of time that we have. Well, as usually, we were wondering how many people out there had thought about the question of what is the fastest event ever measured? So Daniel went out there once again to ask people, what do you think is the most fleeting or fastest physical event ever measured? Thanks very much to our listeners who answer these questions very, very quickly. I'm very grateful for your contributions to help us. contributions that helps me understand what people are thinking about.

And I hope you enjoy hearing your voice on the air. And if you are out there listening and would like to hear your voice answering these questions, please don't be shy. Write to me to Questions at Danielanhorpe.com. So think about it for a second. What do you think is the fastest thing humans have ever detected? Here's what people had to say. I don't know what the smallest time slice ever measured is.

I'm going to assume that it's somehow around femtoseconds. I don't know why that number sticks my brain, but I'm going to say femtose seconds. The smallest amount of space ever measured, I think, is the plank space. I'm going to go with plank time? That's easy. It's the time between when butter goes from being soft to being soup. But actually, it's probably 10 to the negative 20 something, at which point I guess It doesn't even show that time makes any sense anymore.

All right. We've got some cooking answers here. You know, some people listen to our podcast while they're making dinner, and that might have influenced this answer. Well, I'm very interested in this recipe where you make soup out of butter. You've never had butter soup? Oh, man, delicious. That sounds so healthy, so healthy.

Yeah, I'll have butter soup, low-fat version, please. Yeah, that'll definitely shorten. your time on earth, for sure. I mean, expand your space, but shorten your time. I mean, that seems like the wrong proportions you want to go with. Well, butter chicken is a very popular recipe, so I'm sure butter soup is a thing people can make. Mmm, but butter chicken soup. Oh, my goodness. What's better than butter chicken soup? What are the physics of that? How does that even work? It definitely adds mass. But yeah, it's definitely an interesting question. And so let's jump into it. Daniel, first of all, I guess let's talk about time

in general and the idea that maybe time is pixelated or there's a minimum amount of time in the universe. What do physicists think about that? Physicists really have no idea how time works. All right. We're done. Yeah. So it's about time we gave up. Yeah. This will be the shortest episode ever. What's the shortest podcast about physics ever recorded today's episode? Yeah. Every podcast just we don't know, done. No, it is really an enduring mystery. And it's weird because time is something we sort of feel like we understand. It's part of our everyday lives. We talk about all the time. We all have complicated schedules. We rely on time. We do time zones. We mess them up and miss meetings. Time is both familiar and also mysterious because we don't understand like what

it is. Special relativity tells us that it's deeply connected to space and it makes actually much more sense to think about time and space together as one unit, space time. And that makes sense because some of the things in special relativity show us that space and time are mixed, that, you know, moving quickly through space can affect your measurement of time, all these sorts of things. Sort of the same way that, like, electricity and magnetism make more sense when stuck together into one idea. It doesn't tell you that electricity and magnetism are the same thing, just that they're connected in the same way space and time are connected. They're not the same but they're related to each other in special relativity.

Right, because I guess we grow up, you know, not just as kids, but also like sort of through elementary high school, thinking that space and time are sort of immovable, right, like fixed in the universe. But really then eventually you learn that space and time are both kind of squishy, right, and variable. Like time can slow down, time can speed up, space can contract, space can expand, they can both wiggle.

But where did this idea that maybe time is pixelated, where did it come from? Or what would make physicists think that it might be? Yeah, it's fascinating. You sort of trace the evolution of the ideas. And we all sort of have that same experience, like Newton thought of space and time as absolute and fixed, as you say, sort of immutable.

They're like the backdrop of the universe. But then Einstein showed us that they're not actually. They're flexible. They're interconnected. But most importantly, Einstein's theory of general relativity and special relativity still suggests that time is continuous. It's smooth. It's infinitely divisible.

That it's not discrete or pixelated. It's not like there are steps in time. In Einstein's theory of the universe, you can take any two moments and there's always another moment in between, right? There's no minimum time step in Einstein's universe. And general relativity describes the universe very, very well. It describes the expansion of the universe and the motion of galaxies and everything we've ever been able to test about general relativity has always been bang on exactly correct.

with astonishing accuracy. Now, when you say the answering theories suggest that, what does that mean? Does that mean that it only works with continuous time or that it's just always used continuous time and nobody has thought about applying it to the pixelated time? Yeah, great question. It works assuming that space is continuous.

So you're like, let's start from that assumption and then build on top of that. And then you could ask, well, could you have a different theory that didn't make that assumption? What if you assumed instead that space was pixel? And then you run into all sorts of mathematical problems that nobody has been able to solve before. The motivation for that comes from quantum mechanics. Like you might ask, well, why would you make time pixelated?

It feels pretty smooth to me. I mean, we measure it in seconds, but we know there's always milliseconds below those and microseconds below those. Why would you ever imagine there would be pixels? And that comes from the idea of quantum mechanics, which tells us that the nature of reality is sort of discrete. It's like made out of chunks. It's not smooth. You know, like when we look at a beam of life, from a flashlight, Einstein's actual discovery

from the photoelectric effect tells us that it's not just like smooth beams of light that you could like chop up infinitely small, that there's like a minimum brightness because light comes in packets, these little things called photons, right? And so quantum mechanics suggest that even though the universe seems continuous and smooth,

when you zoom in, it really is kind of pixelated. It's just like when you look at your computer screen and you zoom in, it seems smooth, right? But actually there's little dots there. They're a little basic units. So that's the motivation. Right. Like even this podcast is pixelated, right?

Like we're recording into a digital device. It's recording it with a time sample, with a minimum time sampling rate. And then it gets transmitted as bids. And then it plays out there where you're listening to this as those little bits. Yeah, you're exactly right. Digitization is creating some pixelization, right? You're creating these units in exactly the sort of way quantum mechanics works. Fascinatingly, though, even analog measurements have a resolution, right?

Like a photograph, you think of it as like, oh, it's photons. It's not like pixels, like a digital camera or a analog recording on like vinyl or on a tape. It's not using digits. It's analog. It's using some sort of like magnetic technology to record it or like physical bumps on the vinyl. Still, that is discreet, right? Because in the end, there's a finite resolution. Like for photographs, there's a resolution of a photon or the molecule of the molecule of

the chemical atoms that are, you know, recording the light or on the tape, there's still the resolution of like the little magnets that are aligned to record your information or on the vinyl. There's still like the chemistry of the vinyl itself. So analog is higher resolution, but it's not infinite resolution, right? And so the idea is that maybe time is also pixelated? Yeah, because it's weird to think about time as infinite. You know, we don't see infinities in reality.

Everywhere we see infinities in our theory, always something acts to. to prevent it from happening in reality. And this is what quantum mechanics tells us that there are new infinities, you can't divide things infinitely small, and maybe space itself and time are pixelated. Maybe there's a minimum unit of space and a minimum unit of time.

This would be very natural from a quantum mechanical point of view. You asked earlier like, well, has anybody tried that? What if you built general relativity out of discrete units of space and time, you know, pixelated universe? And people are trying to do that, but bringing together the ideas of general relativity and the ideas of quantum mechanics to make that new concept like a theory of gravity and space and time that's built on discrete units has so far not been successful. People have been trying for decades. You run into all sorts of mathematical problems doing so. So we don't have a theory of general relativity that's built on discrete time. So we have this theory of general relativity tells us by space and gravity but assumes continuous time. And then this idea that the universe is quantum mechanical and time and space are probably discrete, but we can't bring these things.

two things together. Right. But this theory, even though it comes from Einstein, does have its problems, right? Like it sort of breaks down, especially when you get down to the smallest levels of particles in quantum physics. Yeah, exactly. Genre relativity is very, very accurate, but everything we think in physics has its limitations. Like every theory you describe is applicable only in certain situations, situations where you've

derived it, you know, under the assumptions that are valid. And so as you mentioned, like general relativity, we think. breaks down in certain situations. Like, number one, it can't describe particles. Like, what is the gravity of a particle? We don't know because particles have uncertainty. General relativity can only tell you about how space is bent when you know where a mass is. Well, what if you don't know where it is? What if it only has a probability to be here and a probability to be there? Is space probably bent or space bent on average? We don't know the answers to these questions. So we don't know how to do general relativity for quantum particles. And it makes weird predictions.

Are we ever going to find out? Like, how are we going to tell if the universe is pixelated in time ever? Yeah, those are two great questions. Will we ever find out how general relativity or how space is bent by quantum particles? There's a bunch of really cool, clever experiments. Well, one way to do it is to try to come up with a theory of quantum gravity that mirrors these things together and tells us sort of like conceptually how time might work. Another is to try to like, make approximate calculations and guess even without the theory of quantum gravity. And you heard one of the listeners talk about the plank time. And another is to try to make fast measurements and see, like, can we zoom in on stuff in the universe

and see if we can measure these pixels, if we can notice some like discrete unit of time happening in our experiments? Like we might measure something in an experiment and actually see the pixels of time. Yeah, exactly. The way you can like zoom in on a screen and see the pixels are there, right? or you could slow down a movie and notice, oh, it's not actually continuous motion. It's just a bunch of still frames.

If you could zoom in on the physical universe in time, then you might notice those time pixels if they're there. Yeah. Well, I guess the question is how fast are things in nature? And the second question you can ask is, what's the fastest thing that we can measure or that we have been able to measure so far? So let's dig into both of those small questions, I guess,

Short questions? Probably not. But unfortunately, it's time to take a quick break. December 29th, 1975, LaGuardia Airport. The holiday rush. Parents hauling luggage, kids gripping their new Christmas toys. Then, at 6.33 p.m., everything changed. There's been a bombing at the TWA terminal.

Apparently, the explosion actually impelled metal glass. The injured were being loaded into ambulances, just a chaotic, chaotic scene. In its wake, a new kind of enemy emerged, and it was here to stay. Terrorism. Law and order, criminal justice system is back. In season two, we're turning our focus to a threat that hides in plain sight. That's harder. to predict and even harder to stop.

Listen to the new season of Law and Order Criminal Justice System on the IHeart Radio app, Apple Podcasts, or wherever you get your podcasts. My boyfriend's professor is way too friendly, and now I'm seriously suspicious. Oh, wait a minute, Sam, maybe her boyfriend's just looking for extra credit. Well, Dakota, it's back to school week on the OK Storytime podcast, so we'll find out soon. This person writes, my boyfriend has been hanging out with his young professional. a lot. He doesn't think it's a problem, but I don't trust her. Now he's insisting we get to know each other, but I just want her gone. Now hold up, isn't that against school policy? That sounds totally

inappropriate. Well, according to this person, this is her boyfriend's former professor, and they're the same age. And it's even more likely that they're cheating. He insists there's nothing between them. I mean, do you believe him? Well, he's certainly trying to get this person to believe him because he now wants them both to meet. So, do we find out if this person's boyfriend really cheated with his professor or not? To hear the explosive phenomenon, listen to the OK Storytime podcast on the IHeart Radio app, Apple Podcasts, or wherever you get your podcast. I'm Dr. Joy Harden Bradford. And in session 421 of therapy for black girls, I sit down with Dr. Othia and Billy Shaka to explore how our hair connects to our identity, mental health,

and the ways we heal. Because I think hair is a complex language system, right? In terms of it can tell how old you are, your marital status, where you're from, you're a spiritual belief. But I think with social media, there's like a hyper fixation and observation of our hair, right? That this is sometimes the first thing someone sees when we make a post or a reel. It's how our hair is styled. You talk about the important role hairstylists play in our communities, the pressure to always look put together, and how breaking up with perfection can actually free us. Plus, if you're someone who gets anxious about flying, don't miss session 418 with Dr. Angela Neil Barnett, where we dive into managing flight anxiety.

Listen to therapy for black girls on the Iheart radio app, Apple Podcasts, or wherever you get your podcast. I'm Dr. Scott Barry Kaufman, host of the Psychology Podcast. Here's a clip from an upcoming conversation about exploring human potential. I was going to schools to try to teach kids these skills, and I get eye rolling from teachers or I get students who would be like, it's easier to punch someone in the face. When you think about emotion regulation, like you're not going to choose

an adapted strategy which is more effortful to use unless you think there's a good outcome as a result of it if it's going to be beneficial to you because it's easy to say like go you go blank yourself right it's easy it's easy to just drink the extra beer it's easy to ignore to suppress seeing a colleague who's bothering you and just like walk the other way avoidance is easier ignoring is easier denial is easier drinking is easier yelling screaming is easy complex problem solving, meditating, you know, takes effort. Listen to the psychology podcast on the IHartRadio app, Apple Podcasts, or wherever you get your podcasts. All right, very quickly, Daniel, what are we talking about today?

We're talking about the fastest things that ever happened. Not the fastest podcast episode. I think we're already past that point. Maybe somebody out there is playing our podcast at like 10X, so they're understanding the universe is so much faster than us. Whoa. Do we sound like chipmunks now then, to them? We should talk really slowly for those people.

Maybe we should figure out how to encode secret messages by talking backwards. Like if you play the podcast backwards? If you only listen to every 25th word I say, I've been talking in secret messages the whole time. It's for the special audience. It's like you and Taylor Swift. Hiding secret messages. Yeah, it's like those books where if you read only the words

along the left side of the page is a whole second message there. All right. If you take every 25th word Daniel has ever said in all 500 plus episode and you take every 13th word that I ever said in all 500 episodes and you put them in the right order, you'll get the answer to the origin of the universe. Like the universe and everything? Yeah, that's exactly it.

This is the big reveal, folks. Plot twist at the end. Days of the day, we'll reannounce it. Yes, absolutely. But we are talking about how fast things are in the universe. And I guess two sort of basic questions. What's the fastest thing that we know about in the universe? And what's the fastest thing we've ever measured in the universe?

Yeah. So talk to us about how fast things are in the universe. Like what are the different scales that we know about? Yeah, so first of all, there's the unit of the second, right? The second is like our natural unit of time. But it's totally arbitrary. We just made it up. It's not like a physical thing.

You know, light travels a certain distance in a second. There's some cesium atom that oscillates billions of times in a second. But a second tells us something about ourselves and our relationship with time because it's what we feel like is the minimum unit of time that sort of makes sense to talk about between people. It's like the natural rhythm of our thoughts, one second. Is it? I think that's why we pick the second, you know, because it's reasonable. Like you pick a unit so that you're usually talking about small numbers. I mean, we could live our lives with clocks that go down to the microseconds,

but it would be pretty exhausting, you know, if you had to tell your kid like, okay, you can watch TV for 6 billion milliseconds or 6 billion nanoseconds, that'd be confusing all the time. So we tend to pick units so you can say small numbers. I think you're talking about like the scale of a second, not exactly like the second. Like why isn't the second 1.1 seconds, nobody knows, right? Yeah, nobody knows. It's totally arbitrary.

But why is the second not like 100 times longer or 100 times shorter that tells, us something about like the scale in which we live we also talk about like minutes and hours those are really important too but i think you're saying like the second is maybe the minimum amount of time that sort of our brains can grog or understand or grasp yeah exactly we have no smaller time unit that's not just like a fraction of a second that makes sense right like nobody worries about things that happen in the millisecond level on an everyday basis yeah exactly and if you think about the way your body works you know like roughly your heart beats once a second-ish depending on whether you're an athlete or not.

And your eyes, for example, blink in like a tenth of a second. And your eyes can only see things that happen, you know, to like one-thirtieth of a second, which is why you can play a movie with like 30 frames per second, and it looks continuous. Your eye can't tell the difference between that and actual continuous motion. So maybe more, it's more like the one-tenth of a second is really kind of the minimum unit that we were used to thinking about, right? We are used to thinking about things that happen in the blink of an eye.

And I think that's why you choose a unit to be like a second. And you can think about small numbers of it, you know, a tenth of a second or ten seconds. It encapsulates the typical range of human activity. But of course, the physical universe, things happen much faster. You know, like even inside your brain, neurons fire. You know, we think like about a thousand times a second. So the processing speed of your brain is like a thousand times faster than a second. And, you know, tiny particles out there can interact and live for much shorter times.

It's like, do you create a muon in the upper atmosphere because a cosmic ray is smashed into a particle? That muon lives for 10 to the minus six seconds, a millionth of a second. Whoa. And you can zoom in much faster, of course, and think about like what happens in a billionth of a second. Well, in billionth of a second, light travels about a foot. Yeah, light is fast. Light is pretty fast, but it's amazing to think about like slowing time down enough to see light move, right? For light to travel at a small distance.

Usually we think about light is going like around the earth lots of times, but in a billionth of a second, it only goes afoot, which is cool. There are other tiny particles that live much shorter than the muon. For example, if you create a bottom cork, it lives about a billionth of a second before flying off to something else. This is a slice of time. It's hard to even really think about. Like, does that really exist? Is there like a moment when the bottom cork is like there and doing its thing before it decays? It feels almost like zero time already.

Well, I wonder if it feels like zero time. us because we're so slow, you know, in our thinking, but maybe if you have like, you know, microscopic creatures or, you know, really tiny beings that probably think a lot faster, I wonder if that will seem slow to them. Yeah, exactly. It's all relative, right? This choice of a second, it tells us about like how we live our lives. It's relative to the length of our lives and the operating of our brain. But it's arbitrary. Time extends on this enormous spectrum from the many, many, many billions of years down to the tiniest slice. And we're, operating on a tiny little bit of it.

It's sort of like the way we can see a little slice of the visual spectrum, but there's light with much higher frequencies and lower frequencies and the universe is awash in that kind of light

that we don't normally see. It's like our human perspective. But the universe operates on even shorter time scales. You know, if you go down to like 10 to the minus 15 seconds, this is now a femtose second. I wonder if,

because we also know time is sort of relative, right? So I wonder, like, if you create a bottom core near a black hole or in a spaceship going near the speed of light, is that we're going to seem longer lived to us from our perspective?

Absolutely, yeah. And like these muons, for example, that we create in the upper atmosphere, they only live for a millionth of a second. And so you might wonder, like, well, would they ever get down to the surface of the Earth? And the answer is yes. And the only reason they do make it to the surface

is because they're going very, very fast relative to us. So their clocks are running slow. So even though they live for a millionth of a second, that's enough time for them to make it to the surface because that millionth of a second clicks very, very slowly as we're watching them essentially. To them, are you saying they live a millionth of a second

if you're the muon, but to us they actually live longer? To us they live longer, yeah, they travel much further than otherwise because they're going fast and so their time ticks slowly. From our point of view, if you had like a little clock traveling with a muon, you would see its ticks going very, very slowly and it would fly very far before,

a millionth of a second ticked, and then that muon decayed. From its point of view, it only lives for a millionth of a second, but it sees the atmosphere is compressed, because when you're moving fast relative to something, you see it's shortened. So for the muon's point of view, it sees the atmosphere is compressed and short. It can make it to the bottom of the atmosphere, to the surface in a millionth of a second. So that's an example of how special relativity is cool, because from one point of view, it's time dilation, from another point view, it's length contraction. It's really the same physics. But yeah, time is relative. Okay, so what else is fast in the universe? So if you go down to like a femtosecond, how far can

light travel in like 10 to the minus 15 seconds? Now we're talking about short distances. We're talking about like less than a micrometer. And you can go down even further to atto seconds. This is 10 to minus 18 seconds. This is a hard number to think about. It's so short that the number of aught of seconds in a single second is the same as the number of seconds that have elapsed in the whole history of the universe. Like, there's been about 10 to the 18 seconds since the beginning of the universe. And an atto second is one in 10 to the 18th of a second. So it's really an incredible slice.

Wow. That's like if you take a second and you split it into a million and then take each of those and split it into a million and then take each of those and split it into a million times that's what an add a second is. Yeah, exactly. a millionth of a millionth of a millionth. Is there anything that happens at the out of second level that we know about? Absolutely.

There are lots of particles that decay in an out of second. And as we'll talk about a minute, we've actually measured things down to the attosecond. It's sort of incredible. But the universe happens even faster. So we can think about like a zepto second, which is 10 to the minus 21 seconds. This is how long it takes a photon to go from one side of the hydrogen atom to the other side of the hydrogen atom, like super fast photon moving a very short. distance only takes a zeptos second. Pretty zifty. But, you know, down in the realm of fundamental

particles, even a zeptos second can feel like a long time. If we create a higgs boson in the large Hadron Collider, for example, that lasts for a thousandth of a zepto second. It's 10 to the minus 24 seconds. Well, meaning like you create a Higgs boson, but in less than a thousandths of a septa second, it's gone. Yeah. Or probably gone. It's probably gone. Yeah. Each one has a distribution. They're pretty tight. It's sort of like radioactive decay. It's not an exact measurement. It doesn't disappear when its time is up.

There's an average there. But yeah, they live much, much shorter than muons. Muons live forever compared to a Higgs boson. You know, Higgs boson can be born and died 10 to 18 times before a muon decays. Whoa. Digging down even deeper, some of the shortest live particles we know about are things like the W boson, the Z boson, and the top cork. These last for like 10 to the minus 27 seconds.

And that's about as far as we can go in terms of like theoretical stuff that we can describe. And this is just probing theoretically, like what can we describe in our theories of quantum particles that takes this short amount of time? That's about the bottom of it. Meaning like of all the things that we have names for physically in the universe, that's about the shortest scale that we operate it. Yeah, exactly. And you could postulate something that happens shorter. There's no limitation there. Like we think about other particles that are really, really heavy.

that might decay much, much faster. There's nothing that's stopping you from thinking about that. But we don't know of any particles in the universe that operate on a shorter time scale. You can always talk about how fast things go, right? Or light goes, right? Like, can't you say, well, light travels, one zipto, fento, mini second in less amount of time than that? Yeah, exactly. You can always divide time further.

According to general relativity, you can just keep slicing it, and you could measure it the way you described, like how far. is light go. And if space is continuous and time is continuous, you could just keep doing that forever, right? You go down to 10 to the minus a million, you know, 0.0 with a million zeros and then a one at seconds and think about how far light goes there. But at some point, you're beyond the extrapolation, the same way that we talked about like general relativity breaking down, you know, when we go to the heart of black holes and having infinite density, we're not really comfortable thinking about things theoretically smaller than a certain time called the plank time,

which is 10 to the minus 44 seconds. We think that our theory of quantum particles and quantum field theory in the standard model works very, very well down to about that resolution, and beyond that, we don't trust it. I know we had an episode about the plank time, but it was too much time ago, and I don't remember. So maybe for our listeners, what is the plank time? But make it quick. The plank time is sort of two things.

It's on one hand, just like you put together a bunch of physical constants of the universe until you get something that has units of time. And then you ask, okay, what's the number? So you take like the speed of light and the gravitational constant and planks constant. And those all have units on them, you know, energy or meters or seconds, whatever. But you can put them together in a way that cancels and you get a number. And that number is 10 to the minus 44 seconds. And then you can ask, well, what does that number mean?

And, you know, the number doesn't mean anything very precisely. you hear a lot in popular science that it's like definitively the minimum resolution of time. It's definitely not that. It's just like this is what we can do to say roughly where things start to be different. Because at the plank time, or if you rearrange it to the plank distance, or you rearrange it differently to like the plank energy, that's where we think our theories break down, where we need to have some contribution from gravity and some contribution from quantum mechanics. And again, we don't know how to put those two things together.

So we can extrapolate our theories up to about the plank energy or down to the plank time. It's equivalent. But beyond that is basically a question mark theoretically. We don't know how to do calculations that we trust that we can rely on shorter than the plank time. Maybe another way to look at it is that it's sort of like when the things that we know about that happen physically in the universe sort of end, right? Like we don't know of anything that's smaller than the plank distance or we don't know of anything that happens shorter than the plank time scale. and so it's like unknown territory. Yeah, it's unknown territory.

And it's unknown territory. We can't even like really think coherently past it. Like we've never seen anything at 10 to the minus 44 seconds, but we can talk about it. We can calculate it. We can imagine it. We can use our theories. But beyond that,

we don't even really know how to think about it carefully. Like you could think about it not carefully. You could say, well, I'm just going to use general relativity and assume it is correct and talk about infinite slices of time and infinitely short distances like try. Well, you could do that, but nobody believes that that describes reality.

The same way nobody believes that there's a singularity, the heart of a black hole. It's a naive extrapolation of general relativity beyond what we think is reasonable. And so we can't even really think coherently about it. Sort of the way we can't think coherently about what happened before the Big Bang, because for the same reason, our theories break down there. We need a theory of quantum gravity to take us further back. So we don't even have like mental theoretical pictures that we can trust. Right, right.

All right, well, that's kind of a picture of how fast things move in the universe. Now, Daniel, how fast do kids grow up? Faster than that or slower? It feels like a million years every hour when you're in it, and then it feels like a millionth of a second when you're looking back on it. Now is there a physical effect, a name for that? It's called the theory of relations. Theory of relatives, yeah.

That's what I was going to say, the theory of relatives. Yeah, relative theory of relatives. Parental time. dilation in the theory of relatives. But no, we have been doing our best to try to understand how fast things actually happen in our universe, not just think about them theoretically and lots of really cool, amazing techniques out there to measure really, really short slices of time. I guess what we've been talking about are things that we know happen in super short time

scales, but then there's the other question, the flip side, which is which of these events can we actually measure and see for ourselves that they happen at that time scale? go. Yeah. So let's get into that technology. But first, let's take another quick break. December 29th, 1975, LaGuardia Airport. The holiday rush.

Parents hauling luggage, kids gripping their new Christmas toys. Then, at 6.33 p.m., everything changed. There's been a bombing at the time. TWA terminal. Apparently, the explosion actually impelled metal glass. The injured were being loaded into ambulances, just a chaotic, chaotic scene. In its wake, a new kind of enemy emerged, and it was here to stay. Terrorism.

Law and order, criminal justice system is back. In season two, we're turning our focus to a threat that hides in plain sight. That's harder to predict and even. even harder to stop. Listen to the new season of Law and Order Criminal Justice System on the IHeart Radio app, Apple Podcasts, or wherever you get your podcasts. My boyfriend's professor is way too friendly, and now I'm seriously suspicious. Well, wait a minute, Sam, maybe her boyfriend's just looking for extra credit.

Well, Dakota, it's back to school week on the OK Storytime podcast, so we'll find out soon. This person writes, my boyfriend has been hanging out with his young professor a lot. He doesn't think it's a problem, but I don't trust her. Now, he's insisting we get to know each other, but I just want her gone. Now, hold up. Isn't that against school policy? That sounds totally inappropriate. Well, according to this person, this is her boyfriend's former professor, and they're the same age.

And it's even more likely that they're cheating. He insists there's nothing between them. I mean, do you believe him? Well, he's certainly trying to get this person to believe him because he now wants them both to meet. So, do we find out if this person's boyfriend really cheated with his professor or not? To hear the explosive finale, listen to the OK. Storytime podcast on the Iheart radio app, Apple Podcasts, or wherever you get your podcast. I'm Dr. Joy Harden-Brandt, and in session 421 of Therapy for Black Girls, I sit down with

Dr. Ophia and Billy Shaka to explore how our hair connects to our identity, mental health, and the ways we heal. Because I think hair is a complex language system, right, in terms of it can tell how old you are, your marital status, where you're from, you're a spiritual belief. But I think with social media, there's like a hyperfixation. and observation of our hair, right? That this is sometimes the first thing someone sees when we make a post or a reel

is how our hair is styled. We talk about the important role hairstylists play in our community, the pressure to always look put together, and how breaking up with perfection can actually free us. Plus, if you're someone who gets anxious about flying, don't miss session 418 with Dr. Angela Neil Barnett,

where we dive into managing flight anxiety. Listen to therapy for black girls on the iHeartRadio app, Apple Podcasts, or wherever you get your podcast. I'm Dr. Scott Barry Kaufman, host of the Psychology Podcast. Here's a clip from an upcoming conversation about exploring human potential. I was going to schools to try to teach kids these skills, and I get eye rolling from teachers or I get students who would be like, it's easier to punch someone in the face. When you think about emotion regulation, like you're not going to choose an adaptive strategy,

which is more effortful to use. unless you think there's a good outcome as a result of it, if it's going to be beneficial to you. Because it's easy to say, like, go blank yourself, right? It's easy. It's easy to just drink the extra beer. It's easy to ignore, to suppress, seeing a colleague who's bothering you and just, like, walk the other way. Avoidance is easier. Ignoring is easier.

Denials is easier. Drinking is easier. Yelling, screaming is easy. Complex problem solving, meditating, you know, takes effort. Listen to the psychology podcast on the online. iHeartRadio app, Apple Podcasts, or wherever you get your podcasts. All right, we're talking about the fastest things in the universe, or I guess the fastest events in the universe, the things that happened at the shortest time scale.

Yeah, exactly, the most fleeting things in the universe. Yeah, yeah. And this podcast is, I think, I think, had it for maybe the longest events. in the universe. But let's get to it because we're going to run short of time soon. Yeah, so when we try to see things happening in the universe, we do something pretty basic. We take slow motion footage.

Like if you're taking a movie and you measure 30 frames per second and then you play them on the screen at 30 frames per second, then everything plays like normal. But if instead you take like 300 frames per second and you play them on the screen at 30 frames per second, then time looks slow in the movie. Everything is slowed down. You can see Usain Bolt running at reasonable rate.

You can see fast things happening more slowly. So that's what we try to do is we try to develop cameras that can basically take pictures or make measurements equivalently much faster than 30 frames per second so that we can watch them slow down and try to understand what happens. Right. And it sort of depends on what you're trying to capture too, right? Like the slow motion camera on your phone can capture, you know, your kids running, maybe somebody jumping into a pool pretty good. But if you're trying to capture something faster like a bullet or an explosion, it's not going to be fast enough. Exactly. And in the old days, people used shutters for this.

Like you had a camera and you opened the shutter and you let light in. And if you're trying to take, for example, a picture of a sporting event or when things are moving really fast, you had a really fast shutter setting, right? Your shutters open for a tiny fraction of a second. Whereas if you're taking a picture of something in the dark, like at night, you have a really long exposure to gather as much light, maybe seconds or even hours. Now, what made you think of a camera? I wonder if that, in the history of humanity, if cameras are maybe the first time that we've had something like automated recording

instances of data about the world. Because before that, I imagine, you know, it was maybe people writing things down on a piece of paper. I think that before cameras, we probably had recordings of sound also, right? You could think about the same way. You know, probably within decades of each other,

I haven't looked at the details. but those were analog, probably, right? Yeah, those are definitely analog. The first measurements were definitely analog. It's interesting question, like, how far back do we have, like, data things where we have recordings that are not just eyewitness testimony? You know, I mean, Galileo, for example, has his drawings of the night sky. And in some sense, that's still data, right?

It went into his eye and out his arm. So he's sort of the recording device there. Yeah, well, that's what I mean. Like, I wonder, for most of the history of science, people were just writing things down a piece of paper. Yeah. But maybe the cameras where you expose a piece of film or played for a certain amount of time, that's maybe some of the first times that we had kind of this idea of a mechanical recording of what's happening in the universe. Yeah, very cool question.

I'm not sure. We'll dig into the history of that. Maybe I'll look into that for an episode. But these days, we use digital cameras, right? And these digital cameras can be very, very fast. And the technology behind the digital camera actually limits how fast they can go. The way a digital camera works is that a photon comes in the lens the same way it does for a normal camera. But instead of hitting a piece of film, which has like special chemicals on it that react to the light,

instead you hit a pixel, which is a piece of silicon. And the photon hits an electron inside that piece of silicon, and then the electron is like free. It's like bumped out of a little hole it was stuck in. It can move along a little bit. And then it drifts along to the edge of the pixel, and it gets picked up by some electronics and measured. That's how an individual pixel works inside your digital camera. It's this interaction between the photon, the electron, the electron causes a little bit of current. And those can be really fast.

Like, you can get CCDs or CMOS devices, which are more modern, which can take pictures down to millions of frames per second. Well, you mean like the camera in my phone can do that? Not necessarily the camera in your phone, but like very high tech CMOS and CCD devices can do this. People who want to take pictures of lightning or like fuel in a plasma dissolving or very high speed scientific events, they have specialized cameras that can get down. to millions of frames per second. In order to be that fast, you need very small pixels with very fast electron drift time.

That's what in the end limits it. How long it takes the electron once it's been freed to slide over to the part of the pixel where it gets red out. If you went really, really high-speed cameras, you're gonna make some sacrifices in the design to make it that fast. So then it's not as good for like taking pictures of your kids,

but it's really good for measuring fast things. You might be able to catch the exact point at which they grew up and record it forever. Yeah, exactly. They started rolling their eyes at you instead of laughing at your jokes. Yeah, there you go. That slow roll of their eyes, you can have it at a millionth of a second resolution.

Yeah, and these are cool devices. I actually played with one for one of my first science projects when I was a summer student, using it to take pictures of lightning in the skies in New Mexico with thousands of frames per second, which is pretty cool. It's amazing to see the world slowed down. But I wonder why you bring up cameras. I know cameras are used in like astronomy, right? Like those big telescopes, they have basically camera sensors at the end of the telescope.

But how much are cameras used in like physics labs? Well, it's a little bit philosophical. You know, you could think of our particle physics detector as kind of a camera. You know, it's a bunch of pixels arranged around a collision point. It takes an image in some sense. A camera really is just an array of detectors. You know, any kind of detector you have, just make an array of them. So you get some sort of like spatial.

measurement as well as time. You know, that's really what a picture is. It's just like a bunch of measurements all in an array. Wait, are you saying that the Large Hadron Collider, the $8 billion machine there, and we could have just used the cell phone camera? Yeah, actually, that's what we did. We just bought one iPhone and we kept the rest of the money for ourselves. It's just a whole bunch of iPhones arranged around the collision point.

Your hard-hitting investigative journalism right here has exposed the scam today on the podcast, yes. No, but seriously, like what's the difference? between the sensors that the large had in Collider and, like, myself, one camera. Do they work faster or are they basically the same? They are basically the same. I mean, actually, the devices near the center of the collision, the fastest, smallest devices we have, are silicon devices. And we borrowed the technology from the semiconductor industry, which use them to develop chips and cameras.

So we're basically piggybacking off of that technology. It's a little bit different because we apply higher voltage across these pixels to make them read out a little bit faster. But it's fundamentally the same thing, yeah. Wait, wait. So then when you take a picture of a Higgs boson, can you put it in portrait mode also? You can do the touch-up thing? Or can you apply like filters too? Yeah, absolutely.

I like my sepia Higgs boson, oldie-timey Higgs boson. Or like the Higgs boson with bunny ears or something? All the best scientific papers have bunny ears. Absolutely, yes. Yeah, I know. It would be very popular in TikTok. Yeah, but in the end, this is limited in time. You know, the large Hadron Collider, we don't need things.

much faster than that. We have millions of collisions per second. And so that the fact that our devices can read out millions of times per second is fast enough. We don't need to go faster. But there are people who are interested in things that happen in like a trillionth of a second instead of a billionth or a millionth. There are special devices, special cameras that can take footage with trillions of frames per second. Wait, wait. So you're saying at the large hydrogen collider, you don't care about things or you can't measure things that happen faster than a millionth of a second. We don't care about things that happen faster than that. that. We can't resolve it anyway. It would be much more expensive to have our devices be able to do that. But we only have one collision. I know you need the latest iPhone probably.

We're interested in one collision at a time, right? So if we only looked at one collision, we wouldn't need to be very fast. You just have a collision. It sits in your detector. You read it out. It's like a single picture. We're not taking movies of these interactions. We only take one picture basically per interaction. Oh, I see. But could you? Would you? Would you look? learn more if you could take a slow motion movie of like two protons hitting each other? We can't actually instrument the collision itself, only the stuff that flies out of it. And so in the end, we're just sort of looking at the debris. And sometimes we are interested in like when bits arise because it tells us like how fast they're moving. So we do have some specialized time of flight detectors.

People develop to see like, did this photon arrive before that electron in the same collision or not? So we do sometimes dig into that a little bit. But mostly we just care about what flew out. We don't usually care about, like, what the order was or the sequence of events doesn't really tell us that much more. And it's really, really hard to do, especially that fast. Interesting. But you're saying that there are, as we talked about before, there are physical events that happen in a much shorter time scale.

And so for that, you need even better cameras. Yeah. And these are called streak cameras. The idea of a CCD or CMOS devices, a photon releases an electron, and then you pick up those electrons. But you don't distinguish between an electron that arrived near the end of your time cycle. and near the beginning of it. Within a single frame, you count those electrons the same way, and that loses information.

If there are things happening faster than your time cycle, then your frame, then you're losing them. So a streak camera tries to take advantage of that and applies a time-varying electric field. So electrons that are released at one moment and electrons are released another moment will end up in different directions.

So it sort of like sweeps a single frame across something in space and like spreads it out. That's why it's called a streak camera, like takes these electrons and sprays them across something so you can tell when they arrived. Well, wait, wait. So this is like a sensor just like the camera or is this a different kind of sensor? It's fundamentally like a camera, right?

A photon comes in and releases an electron. But instead of just letting the electrons drift across your pixel, you know, guiding these electrons to different places, like on a mini screen based on when they arrived. So sort of instead of catching the electrons in a bucket, you sort of sweep the bucket. so that you can tell when the electrons were released, which tells you when the photons arrived at your sensor. Exactly. Yeah.

So where the electron hits tells you when it was created, which tells you when the photon arrived. So then you could tell the difference between a photon that arrived to the beginning or the end of your frame. And this gets you more time resolution. Yes, exactly. And so street cameras go down to like 10 to the minus 14 seconds.

The fastest that I found was one that can do 70, trillion frames per second. That's like a lot of pictures of your kid picking their nose. Yeah. Well, depends how quickly they do it. But what kinds of things are being measured with this crazy camera? Like,

what are they trying to do? These things are used to understand like biochemistry and some kind of interactions, you know, like proteins folding or bonds forming, you know, basically chemicals interacting, this kind of stuff. but you know lots of people are just curious and nobody really knows it's sort of like uncharted territory

there are things we think happen in a certain way and it might be that if you slow them down they happen differently this weird stuff happening that nobody expected so it's sort of like exploring the unknown so people are using street cameras to explore all sorts of things hoping to find something new now this is if you're trying to capture photons right yeah in order to like take a picture of something right right but you can also just measure things in other ways right like the voltage or something or measure, I don't know, the magnetic field or something. Would those be able to be measured faster? Yeah, absolutely. There's not a fundamental limitation there.

You know, the question is really like, can you capture something which varies that quickly? Can you isolate it? And in order to do that, you need to like probe it. You need to like create something that happens at that fast time slice so that you can take a picture of it. You need like something that happens really quickly and then something that can respond very quickly and then something that can record that. And people are really pushing the forefront of that technology. This is actually what won the Nobel Prize in 2023 is making super duper short laser pulses down to the ato second, down to 10 to the minus 18 seconds. And these were super short laser pulses created by layering longer laser pulses on top of each other.

They sort of like interfere with each other to make a super short pulse. And you can use this to like probe things that are happening inside the nucleus. or inside an atom, you can, like, give it a super short kick and see what happens. How does that help you measure of something fast, a short laser pulse? They use this technique called pump probe measurements. Basically, you shoot this laser pulse at the thing you're trying to look at, and you take one measurement of it. So you have, like, one measurement of where your electron is after you zapped it with a laser.

And what you're really interested in is like a movie. So you want to see, like, how does the electron jumping from one energy level to another or from one atom to another? So you zap it with this laser pulse and you take one measurement of your electron. That doesn't give you a whole movie, but you can do it over and over again. So if you can set up the same system over and over again and zap it with a laser pulse at slightly different times along the process and take a measurement each time, then you can put them together into a movie. So it's like if you watch your kid do a long jump and you take a really fast picture, but only one picture per long jump, and then you stitch them together into a whole description. of the long jump because you were able to take really fast pictures you have now a very slow motion

movie of the long jump it's really a movie of like a thousand long jumps where you took one picture from each so it's not exactly the same thing but in principle they are very fast measurements of this event i think i see what you're saying this is like a flash basically right yeah you're basically creating a super fast flash which lets you capture what's going on even if that thing is going super duper fast by having a really short flash you can get a picture of it because otherwise like even the flash in your camera takes a while and so if anything happens faster than that it'll just get streaked in your photo yeah exactly like remember those strobe photographs people develop really fast flashes and they took pictures like a bullet going

through an apple you don't need a really fast camera if you have a really fast flash and everything is dark otherwise because then you're only illuminating it during one very brief moment now imagine you did that same experiment a million times and you turn the flash on a slightly different time each time you'd have a whole movie, a whole slow-motion movie. It'd be from different bullets hitting different apples, but in principle, you'd put together the dynamics of what's happening. All right, so that's a camera then that can take pictures. It's essentially sort of every at a second.

Yeah. The limitation so far is 43 attos seconds. So this is really getting to the edge of what we can do. But the fastest thing ever measured actually does get down to the Zepto second. This is a really cool technique where they shoot a photon and a molecule that has two electrons. So say, for example, you have like H2, which is two protons and two electrons, right? Two atoms of hydrogen bonded together. You shoot a photon at it, and it actually interacts with both electrons.

Okay, so this single photon, like, hits one electron, and then it hits another electrons, and those electrons react, right? Both of them generate some signal, and those signals interfere. And by looking at the interference between the light generated from those two electrons, you can see this time difference. So you can tell that the photon hit one and then later it hit the other one. And the time difference between those two things is about 250 zepto seconds. Whoa. Now, what does this help you measure?

What can you use it to take a photograph up? It lets you declare yourself the king of time, man. This is the fastest thing ever measured. So in one sense, this is just like, and just. engineers being awesome and like trying to make things as fast as possible just for the purpose of making things as fast as possible. Well, first of all, Daniel, engineers are awesome. Yes. Just by being engineers.

Yes. Even when they sleep in and sit around in their pajamas and doodle cartoons all day, engineers are awesome. Exactly. I mean, that's even more awesome. Let's face it. Absolutely. That's the pinnacle of awesomeness. Obviously, right?

Like, who wouldn't I want that job? Without doubt, without doubt. But, you know, if you're interested in how H2 works and how electrons interfere with each other, you know, and understanding the system and all is full glory, usually we think about like an individual electron one at a time, but really it's a complicated system where the electrons can interact and affect each other. If you want to understand the finite gradations of energy levels in H2, then this can help you understand that by poking one electron and poking another.

So what is it actually measuring, like the difference in time between when the electrons came out of the atom or just when the photons hit each of the atoms or what? Yeah, it's measuring those two electrons. So you're knocking both electrons out of the atom. And then you're making measurements of those electrons. And because they're sort of almost on top of each other, those two electrons can interfere. And the interference pattern lets you recover

that there's a time difference between the two electrons when they get knocked out. And the normal measurement, you think, oh, both electrons came out at the same time. But now you're saying we can actually tell, like, oh, this one, the right one came out first, then the left one. Exactly.

And the difference in time is really minute. it's two times 10 of the negative 19 seconds. And that is the fastest thing ever measured. Whoa. That's even faster than the Higgs boson? That's not faster than the Higgs boson, but we've never measured the lifetime of a Higgs boson. The Higgs boson lifetime, 10 to the minus 24 seconds,

that's theoretical. Like we don't know how long the Higgs boson lasts. We haven't measured it actually. Maybe if you install a new iOS on your large Hadron Collider phones, I hear it's a particle physics portrait mode. There's a way indirectly to understand the lifetime of the Higgs boson because it's connected to its mass and how different Higgs bosons have different masses. And there's a bunch of theory that lets you say if you measure the mass of the Higgs boson,

you can then extrapolate to know what its lifetime is, but that's not the same as actually measuring its lifetime. That theory could be wrong. So we haven't been able to resolve the lifetime of Higgs boson, like the time between when it's created and it decays. And even this zepto-second measuring device is like a factor of 10,000 too slow to observe a Higgs boson. Well, I guess maybe what you mean, like this is the fastest physical event we've seen with like a camera, basically. Yeah, with a camera where like the definition of a camera is kind of loose here because we're not like getting pixels or images here.

We're just sort of making measurements after illuminating it, right? We flash it with an x-ray, then we take some measurements. Right. So this is the fastest event that we have a pick for. So definitely it happened. Exactly. Because otherwise, it didn't happen. Yeah. Picks or it didn't happen. And this is the fastest. Pigs or it didn't happen. Yeah, exactly. And we think probably the universe is operating on a much shorter time scale. We do these calculations. We're pretty confident in our theory about Higgs bosons and WZ's bosons.

So we think it's happening, but it's not the same as actually seeing it. All right. Well, it's kind of this interesting. interesting convergence of technology and theory, right? It's like this is where rubber meets the road, basically, right? Like, you have these theories, but then you need actual measurements to prove that these things are happening at those timescales. And that's where the technology is right now. That's right. And the experimental technology, actually taking these pictures, is still like 25 orders of magnitude away from the theory.

Like the theory will work down to 10 of the minus 44 seconds. We've only measured down to 10 of the minus 19 seconds. So there's a long way to go. No, so we're halfway there. Sure. We've done that in, what, 20 years? So. Yeah, the same way that like getting $1,000 is like halfway to a million dollars, right?

It's just 10 to the 3 instead of 10 to the 6. Yeah, exactly. If you're thinking logarithmicistic scale. Actually. Or the way inflation is going right now. That sounds pretty much the same. Totally fair. Anyway, we're making progress and we're illuminating the universe at smaller and smaller time

slices. Maybe eventually one day we'll, see it at its smallest time slides and discover the granularity of the universe itself. Yeah, and we can measure the progress of human eyes to see the fast things in the universe. Daniel, when should be the next podcast episode where we sample how fast things can be measured? You know, things are happening pretty rapidly, so maybe in the next couple of years, some we will break this record. In which case, we might set a new record for what's the fastest change in how fast we can measure things measured by a podcast.

in portrait mode. Yeah, and maybe by then we'll be making millions of dollars instead of thousands. Yeah, by then. We're halfway there. Yeah, hopefully, hopefully. We can only hope so. And maybe by then, I'll actually remember what we talked about in the episodes. Sounds like a plan.

All right, well, we hope you enjoyed that. Thanks for joining us. See you next time. For more science and curiosity, come find us on social media, where we answer questions and post videos. We're on Twitter, Discord, Insta, and now TikTok. Thanks for listening, and remember that Daniel and Jorge Explain the Universe is a production of IHeartRadio.

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