Daniel and Kelly’s Extraordinary Universe - Listener Questions 47: Gravity, Time, Photons

Episode Date: January 23, 2024

Daniel and Jorge answer questions from listeners like you! Ask your [e-mail] 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

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. Wait a minute, Sam. Maybe her boyfriend's just looking for extra credit. Well, Dakota, luckily, it's back to school week on the OK Storytime podcast, so we'll find out soon. This person writes, my boyfriend's 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 or gone.

Hold up. Isn't that against school policy? That seems inappropriate. Maybe find out how it ends by listening to the OK Storytime podcast on the IHeart Radio app, Apple Podcasts, or wherever you get your podcasts. Every case that is a cold case that has DNA. Right now in a backlog will be identified in our lifetime. On the new podcast, America's Crime Lab, every case has a story to tell. And the DNA holds the truth. He never thought he was going to get caught. And I just looked at my computer screen.

I was just like, ah, gotcha. This technology's already solving so many cases. Listen to America's Crime Lab on the IHeart Radio app, Apple Podcasts, or wherever you get your podcasts. Do we really need another podcast with a condescending finance brof trying to tell us how to spend our own money? No, thank you. Instead, check out Brown Ambition. Each week, I, your host, Mandy Money, gives you real talk, real advice with a heavy dose of I feel uses, like on Fridays when I take your questions for the BAQA.

Whether you're trying to invest for your future, navigate a toxic workplace, I got you. Listen to Brown Ambition on the IHeart Radio app, Apple Podcast, or wherever you get your podcast. Hey, Daniel, we've been answering listener questions for years, right? Yeah, more than five years, actually. Wow, that's wild. But do you think it's making a difference? Like, are we making a dent in humanity's understanding of the universe? You know, I think every time we answer one person's question, we move all of humanity forward a tiny little bit.

Forward towards what? Towards the forefront of human knowledge. And what's there? The vast abyss of our confusion. I was going to say if there are treats there, like do you get a lollipop? No, it's mostly just a bunch of scientists, scratchy. their head. Eating lollipops.

Sometimes, that's all you can do. But can you sense humanity moving forward a little bit each time you answer a question? I guess so. I mean, the nature of questions we get has been changing. Sometimes people ask follow-up questions to answers to other people's questions. Wow. So we're moving forward. That's pretty cool.

But what happens when we reach the edge of your understanding and humanity's understanding? Then we declare success and I retire. As a physicist or as a podcaster? Yes and yes. But wait, if we reach that point, don't we need more physicists? If we reach that point, then everybody's a physicist. And then everyone gets a Lollipop. And a podcast.

Hi, I'm Horamie Kartunis and the author of Oliver's Great Big Universe. Hi, I'm Daniel. I'm a physicist and a professor at UC Irvine, and I'm a full-time questions answerer. I thought you were a full-time question asker. Isn't that what physicists do? Do you feel like you get paid to answer questions or to ask questions about the universe? Which one pays more? I feel like that's just two sides of the same coin. But when I'm at work, I'm asking questions. And then as soon as I get home, I'm answering them. Who emptied the dishwasher? Whose turn is it to take out the dog? I feel like I'm the answer repository of the family. Interesting. And the dog walker, apparently. Well, there's a quote in one of the Ph.D. movies where someone says, in academia, you're either known as the person who came up with the question or the person who answered the question.

Everyone in between gets sort of forgotten about. Like all those bricks don't matter. It's just the person who puts the cap on the pyramid. Yeah, the person who designs the pyramid and the person who puts the last stone gets all the fame. Yeah, that might be true. But there's a lot of things we learn along the way. I guess you can still have fun doing the questions, trying to answer the questions, and that's kind of what science is all about, right? Trying and failing. Yeah, and it's also fundamentally exploring.

You don't always know where your research is going to end up. You might start out asking one question and answering somebody else's question or a completely different question. That's some of the joy of it, the surprise. Right, right. Like what's going to be inside this lollipop? Who knows? It could be a scorpion, it could be chewing gum. Let's find out.

Let's give it to the dog and they'll find out. Well, what if it has chocolate inside? Oh, no. Oh, no. I hope it's a chicken-flavored lollipop. But anyways, welcome to our podcast, Daniel and Jorge, Explain the Universe, a production of I-Hard Radio. In which we ask all sorts of questions about the nature of the universe,

how it works in the tiniest level, how it comes together to make our incredible reality and how it exists on the grandest scale, expanding and accelerating and zooming photons all to the universe. And we do our best to try to answer some of the questions that we have and that you have about how it all works. That's right, because it is a giant universe full of mystery and unanswered questions. And so in this podcast, we try to think about those questions,

figure out where they came from, what those questions are, and sometimes how to avoid them if we don't know the answer. Avoid them, no, we embrace the questions. We don't know the answer to. Actually, you avoid questions sometimes. Like, if you don't know the answer, you pull this kind of like politician thing where you, very cleverly circumvent the question.

I don't know what you're talking about. There you go. You're doing it right now. But my daughter's been helping us a little bit with our new TikTok account where I walk around campus at UCI and ask people questions. And she's been commenting that the answer of the question is almost always, well, we don't know. Unfortunately, that is the answer still for a lot of physics. But also maybe kind of the fortunate thing, I guess, if you're a physicist, because it means job security.

Yeah, or if you're an aspiring physicist, there's still so much left to figure out about the universe and not just tiny loose ends about how to do 11-dimensional integrals over quantum brains, but really basic stuff about how the universe works. So we encourage you all out there to think about the universe, to try to understand it. And when those ideas don't quite come together, when it doesn't weave itself together into a whole concept in your mind, reach out to us, ask us questions. We will answer. We will help you understand. to us to questions at Daniel and Jorge.com. Maybe what you need to do

on TikTok is do one of those dances that they do on TikTok and then maybe that will distract people from the fact that you don't know the answer. It'll show them

that I don't know the dance either. I guess we'll be testing the theory that any publicity is good publicity. There you go. Or that maybe there's an intricate dance

of the universe in terms of math and physics and the particles that make up reality. I'm going to do two moves at the same time. to show you how an electron can be in superposition of two quantum states.

That's right. And how does that run where it looks like you're floating on the air work? That's what I want to know. That's not physics. That's dance engineering. All right, but questions is sort of the name of the game here. We talk about questions and sometimes we answer questions from listeners. We absolutely do.

Any question that comes into our inbox, we will answer it. And some of those questions we feature here on the podcast because we think lots of people want to know the answer. or I just think it would be a great opportunity for Jorge to make fun of physicists. Yeah, I got to earn my keep here. But yeah, today on the podcast, we'll be tackling. Listener questions number 47. We're getting close to 50, but both in questions, episodes, and an age, Daniel. You know, I'm 48, but once I passed 45, I just decided to round it up to 50.

And then my wife recently turned 45, and I said to her, welcome to the Round It Up to 50 Club. And she was not very happy with that invitation. She's like, nope, I'd like to use more numbers of precision, please. Exactly. She asked me if when I get to 51, if I was going to round it up to 100. There you go. And I said, bring it on.

Maybe you'll gain the wisdom by then of never commenting on your wife's age. See, there are always things to learn. Yeah, there. It is a mysterious universe full of answers to be had. But yeah, we like to answer listener questions here on the podcast. And so today we have three pretty intense questions, I feel like. They're intense, not just in the sense of how complicated the concepts are, but also intense in the sense that it's all about sort of atoms, right, and things at the smallest of levels. Yeah, absolutely. These

folks are really digging into the details of how the universe works and trying to make it click together in their minds. I love it. And so let's jump right in. The first question comes from Noel from Perth, Australia. Hi, Daniel, and Hawaii. This is not a lot of from Perth, Western Australia. My question is, how many atoms does it take before you can measure its gravity? Thank you and keep that excellent content coming. All right, awesome question here. Pretty intense. It has something to do with both the smallest things in the universe and also maybe one of the most significant forces in the universe. Yeah, it's a great question because it really leans in the direction of understanding gravity for little particles, which is so important. It's one of the

biggest open questions in the universe is how does gravity work for quantum particles? Can we unify all the forces into a theory of quantum gravity? And one of the reasons that it's difficult is that it's even hard to see gravity happening on particles because gravity is so weak. It's so much weaker than all the other forces and particles have tiny, tiny masses. So it's almost impossible to see the gravitational effects of little particles. Well, I guess it's not hard to see it. like if you hold up a rock, right?

You know, it's made out of particles and you let go of the rock. The rock will fall down to the ground. So you can see gravity acting on all the particles of that rock. Yeah, absolutely. The whole universe is made out of particles and we see gravity happening. But all those objects we see gravity happening for, these are classical objects where all the quantum effects have averaged out. The rock can be described using purely classical physics,

F equals MA even. You don't even need relativity. And so we can describe gravity there. I think Noel's question is like how small an object can you see gravity happening on? How many atoms do you have to put together before you can measure the gravity of an object? What's the tiniest thing? I see. You're talking about like how to measure the gravity or like how much gravity is being exerted on a small clump of particles or atoms, right? Because like you can take a small clump of atoms and you let it go and it is going to fall to the floor, isn't it?

You're going to see it. A small clump of atoms, if you let them go, will feel gravity, we think. But it'll also feel a bunch of other stuff. If there's any electromagnetic forces that are residual, it'll feel that. That's why, for example, you can use a magnet to overcome the gravity of the earth. Or static electricity can hold something to your head defying gravity. Gravity is so weak that any other force, if it's an all in play, is going to overwhelm it. So that's why you mostly see gravity happening on really, really big stuff where there's a lot of it.

The earth and the moon, for example. Or a rock? or a lollipop or your dog but dogs and lollipops are lots and lots of particles right you're not seeing gravity happen on individual particles there

but I guess I'm thinking of like a gas if you fill up a room or even the gas in our atmosphere you can see the effects of gravity on each one of those air particles right like the air is densest near the surface than it is up in the sky and if you want to think about like

where have we seen gravity in action then thinking about the atmosphere is a great way to do that because the reason we have an atmosphere is because of gravity. Like the moon has no atmosphere, has an exosphere, but it has no atmosphere because it doesn't have enough gravity to hold gas to it. If you turned off the earth's gravity, we would lose all of our particles of atmosphere. When we're actually already losing particles of atmosphere all the time, they boil off the top of the atmosphere if they have enough velocity. And that's something we've studied in great detail. We know that like lighter atoms like helium and hydrogen boil off at

faster rates and heavier atoms don't. We can calculate the escape velocity for a particle to leave the Earth's atmosphere. We do all these calculations and we can even check them against things we've observed. So that's an example of gravity acting on particles in a way that we can calculate and that

we can observe. Right. You can see the macro effects, but I think maybe what you're talking about is like if we want to measure the gravity on an atom, for example, you might be able to see an atom and keep track of it, but you can't maybe ascribe all of its emotion or what it does to gravity. Like it might be affected by other forces which are stronger than gravity, which might

confuse your measurement of its gravity. Yeah, I think there's a few things going on here. One is what you just said, that it's hard to get rid of everything else so we can focus just on the gravity, though people have done that. And we can talk about experiments where people look at the gravitational effects on just pure neutrons, which have no electric charge. But the real issue is that all of this is probing still the gravity. of the earth not the gravity of that particle or that neutron right we're pulling on that object using

the earth's gravity we're not like seeing two neutrons attract each other gravitationally oh i see now you're talking about measuring the gravity between two small the objects like atoms but was that nol's question well noel says how many atoms does it take before you can measure its gravity and so on one hand you can say well the earth is acting with gravity on that object and so by newton's laws they're for the object is also acting on the earth, there's a symmetry there. But actually seeing the gravitational effect of a tiny little clump of stuff, not the effect on it, but the effect of it, I think would be really fascinating. Oh, I see.

You think that the Nol's question is like, what's the smallest bit of stuff that we can measure how much it attracts other things? Yes, exactly. Because you have a neutron or a helium atom in the atmosphere is being pulled on by the Earth. We already know the Earth has gravity, no big deal. How many atoms do you have to clump together before you can feel something having its own gravity, pulling on other stuff? All right, because I think what he's maybe trying to get at is that it's really hard to do it with one atom, and so maybe even possible. But maybe he's thinking, what if I take two atoms or three atoms or four atoms, can I measure the gravity of a small clump of atoms and then just divided by the number of atoms?

Would that let me measure the gravity of one atom? Yeah, exactly. And I think his question is, how small can that? go technologically. Like in principle, any tiny amount of matter has gravity to it. But in practice, it's very difficult to measure this gravity. And so how many atoms do you have to put together before we can like register the effects of gravity before we can actually see the needle go above zero? And I guess maybe this is more of a technical question, like more of an engineering question, right? Like what's the best instrument that we've made to measure gravity? Or maybe he's

talking about a theoretical limit? The theoretical limit is. one, right? Two atoms near each other. In theory, they have gravity. We don't know what the quantum mechanical description of their gravity is, but if we assume they act classically, though of course they don't, then we know how to calculate their gravity and how they bend space and all sorts of stuff. Treat them like tiny planets. We know how to do that theoretically and we think theoretically that there is gravity there. Really just a practical question of measuring it. It's essentially impossible to measure the gravity of an individual atom because it's so tiny and gravity is so weak. So I think Noel's question is an engineering one, which is like, how good have we

gotten at measuring the gravity of tiny bits of stuff? Well, let's start maybe with something large and then try to go down in size. Okay. So what have we started with a bowling ball? Can we measure the gravity inherent in a bowling ball? Have we? Have we done this important measurement in the history of science? Well, I know bowling balls weigh about, what, 10 or 15 pounds? How do you know? They have numbers on the size to tell you. you how happy they are. But not if they drill the holes in them, then it changes. Oh, no.

Oh, my gosh. They're totally inaccurate. Then now we're getting to a theoretical limit here. But that's about six or eight kilos. And that's the kind of thing that we can measure. It's gravity. Absolutely. How would you measure that?

We have these torsion experiments where essentially you put like two bowling balls on the ends of a long rod and then you suspend it from a wire. So it's balanced really, really well. and a tiny push sideways on the bowling ball will make it spin. Then you bring other bowling balls near it, like next to this torsion pendulum, and you see if it spins a little bit. If it spins a little bit, that tells you there's a tiny little force there between the bowling balls.

So this is like the Cavendish experiment. It's the most precise way we know to measure the gravitational constant without knowing, for example, already the mass of the Earth. Okay, so if you do this for a couple of bowling balls, then you can measure its gravity. can see like the force that one bowling ball exerts on the other bowling ball through gravity. And you're pretty sure it's not like, you know, the electromagnetic attraction or vandal world forces between the two bowling balls.

Exactly. And this is really just pure experimental science, like isolating this, keeping it stable, making sure you're not getting shaken by trucks rolling down the highway or affected by static electricity or even by like the force of light on these bowling balls. Remember photons have momentum. So you have to do this experiment like in the dark. And so, yeah, it's a real experimental accomplishment to make this work. Also, you have to make sure your bowling lane is like oiled evenly, right?

That's bowling engineering. That's out of my field of expertise. Yeah, I don't know. Oh, sorry. That's not a physics experiment. So we can measure the gravity of a bowling ball. We have done it, you're saying. And like, how well do we know this like down to what precision?

Like, are we barely getting it, or are we pretty comfortable we know the gravity of a bowling ball? We're pretty comfortable, though we can measure the gravity of six kilo objects and do it pretty precisely. These are still the same kind of experiments we use to measure Big G, although we have a whole podcast episode about how we measure the gravitational constant. And these days, we can measure it using really, really tiny twist of that torsion pendulum. You do it by putting a mirror on the wire, and then you shine a laser on the mirror so that even if the wire turns as tiny as tiny as a torsion. little bit, you can see the laser spot move. It's really clever. Okay, so we've tried it with bowling balls and you're saying we've gone smaller like billiard balls down to maybe even smaller objects. What's the smallest object we've done?

The smallest experiment I could find used three quarters of a kilogram lead weights. Oh. So basically billiard balls. Billiard balls. So that's not that small. I mean, that's only like a tenth of a bowling ball. That's a billiard ball. That's the smallest we've done an experiment on. where the objects are symmetric, where you have the same mass. And that seems pretty small, but remember, that's still a lot of atoms. That's what I'm going to say. It seems like it's huge.

I thought maybe we had measured a thing smaller. Well, it's a pretty huge number of atoms. You know, if you use Avogadro's constant, it's like still two times 10 to the 24 atoms. It's a lot of atoms. There was another experiment where the sizes weren't symmetric. You had like one bigger and one smaller. And in that one, the smaller mass is down to 59 milligrams. So that's a whole lot small.

but it's still a pretty big number of atoms. Well, in this case, you're measuring the gravity of the 59 milligram mass or you're measuring the gravity on the 59 milligram mass. So here, the small mass is the one on the torsion pendulum. So it's the one being moved. So you're not measuring really its gravity. You're measuring the effect of gravity on it. Yeah, so that's a good point.

And so the smallest experiment where the things really are the same size, where they're having the gravitational effect on each other, is three quarters of a kilogram. Or a billiard ball, which, as you said, it's like 10 to the 24 atoms. Yeah, I don't even know what the prefix is for that number. It's a really, really big number. A bazillion. A gazillion.

A ton. Exactly. So engineers have a lot of work to do to get us down to measuring the gravity of one atom. Well, tell me what happens if you try to go smaller. Like, what if you put marbles there? What do you get? You just get pure noise? or, you know, it starts to go wonky.

What happens if you go smaller? So the limitations here really are experimental. It's sort of like LIGO. You're trying to measure a really small effect. And there are other effects that are trying to drown it out. So it's like trying to listen to something really, really quiet. You need a super quiet room. And so in this case, just the shaking of the building, like the seismic noise of the earth,

will shake your apparatus in a way that's more dramatic than the gravity of two marbles or the gravity of two tiny pebbles, for example. So you need to isolate your room. You need to remove from all other effects. Well, maybe the problem is they keep doing these experiments in like a bowling alley. Next to a freeway. Yeah, that's the problem.

Or in a pool, pool hall. So you're saying, like, if you try to measure anything smaller, it's just we don't have the instruments needed to, like, get past just the general noise of the universe to try to measure something that, Weak. Exactly. They keep inventing new instruments to suppress the noise, to be insensitive to the noise.

There's been like a whole 30 or 40 year system of these experiments, each one more precise and more accurate than the last because they figured out some clever way to prevent a source of noise from infecting their experiment, which gives them new sensitivity. And so they keep working on it and they're going to keep pushing it down. And I can see them making progress steadily, but they're nowhere close to measuring it for like one atom. Right, right. now we're like 10 to the 24 orders of magnitude away from order being able to measure that. Yeah, well, that's 24 orders of magnitude. 10 to the 24 orders of magnitude would be 10 with 10 to the

24 zeros. Oh, sorry, yeah. You know what I mean. But I think we've answered Noel's question, which is that he has, how many atoms does it take to before you can measure its gravity? And it seems like the right now the best state of the art is 10 to the 24 atoms. Yeah, though in theory, the answer is one and maybe one day we'll get there. Oh, I see. Theoretically, yes. All right. Well, let's get to these other questions about the nature of matter and reality and quantum mechanics.

But first, let's 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 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 the meets. 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. Hola, it's Honey German. And my podcast, Grasasas Come Again, is back. This season, we're going even deeper into the world of music and entertainment with raw and honest conversations with some of your favorite Latin artists and celebrities. You didn't have to audition? No, I didn't audition. I haven't audition in like over 25 years. Oh, wow. We've got some real G-talk right there. Oh, yeah. We've got some of the biggest actors, musicians,

content creators, and culture shifters sharing their real stories of failure and success. I feel like this is my destiny. You were destined to be a start. We talk all about what's viral and trending with a little bit of chisement, a lot of laughs, and those amazing vivras you've come to expect. And of course, we'll explore deeper topics

dealing with identity, struggles, and all the issues affecting our Latin community. You feel like you get a little whitewash because you have to do the code switching? I won't say whitewash because at the end of the day, you know, I'm me. Yeah. But the whole pretending and code, you know, it takes a toll on you. Listen to the new season of Grasas Has Come Again as part of My Cultura Podcast Network on the IHart Radio app, Apple Podcast, or wherever you get your podcast.

A foot washed up a shoe with some bones in it. They had no idea who it was. Most everything was burned up pretty good from the fire that not a whole lot was salvageable. These are the coldest of cold cases, but everything is about to change. Every case that is a cold case that has DNA right now in a backlog will be identified in our lifetime. A small lab in Texas is cracking the code on DNA. Using new scientific tools, they're finding clues in evidence so tiny you might just miss it. He never thought he was going to get caught, and I just looked at my computer screen.

I was just like, ah, gotcha. on America's Crime Lab we'll learn about victims and survivors and you'll meet the team behind the scenes at Othrum, the Houston lab that takes on the most hopeless cases to finally solve the unsolvable. Listen to America's Crime Lab

on the IHeart Radio app, Apple Podcasts or wherever you get your podcasts. All right, we're answering listener questions here today. We just answered one about bowling, right, in gravity? Yeah, pebbles and lasers and pool balls and bowling. And I think we struck out or got a gutter ball. I don't know. I don't know sports enough to know what the right analogy here is.

Maybe we've got a split on it. I think in bowling they call that a touchdown. Yeah, there you go. All right, well, let's get to our next question. And this one comes from Anik, who has a question about energy levels. of an electron. Hi, my name is Anik Aschner, and I have a question about time and energy levels for an electron. Does it take time, or is it instantaneous when an electron jumps between energy levels?

Thank you. Bye-bye. All right, interesting question. First of all, I guess maybe we should talk about the energy levels of an electron. Like, what is that? What is this question he's asking in the first place? Yeah, so an electron flying around the universe can have any energy. But if you put an electron in a box or like trap it around a proton in a hydrogen atom, then there's only a few solutions to the quantum mechanical equations.

We call those different energy levels. The electron can't just have like any arbitrary energy as it's hanging around the proton. There's like a ladder of energy levels it can exist on. Right. They usually do this visually by kind of going back to the old model of the atom where which had electrons kind of going around the nucleus of an atom in an orbit. like a circular orbit. Do they have to do that?

They don't, but I think that maybe helps people understand it. Like maybe if the atom worked the way people thought it did, which is just like a kind of like a planet going around the sun, maybe the electron was going around the nucleus of an atom, then an energy level was kind of like the size of that orbit, kind of, right? Because maybe a bigger orbit has more energy to it. It's definitely true that bigger orbits have more energy and like planets going around the sun have to move faster

to have a larger radius. The difference is that orbits can have any radius. There's literally an infinite number. Any velocity you pick for your planet, there's a radius where it can sit happily. For electrons, that's not true. There's only a few energy levels where all the mathematics works out.

Right. They're discrete or quantized, which is kind of where the idea of quantum mechanics comes from, or at least an eight. Yeah, that's exactly right. And something I think is really cool that not enough people appreciate is that the quantized energy levels

comes from putting the electron in confinement. An electron out there in free space can have any energy. It's putting it in a box like trapping it around the proton or sticking it in a square well or something that generates

the quantized solutions to the Schrodinger equation. Right. It's maybe kind of analogous to like a guitar string, right? When you start to get into quantum wave functions,

like when you can strain a string from two ends of a guitar, then there are sort of sort of like main ways that it can vibrate, right? Yeah, that's exactly right. A string on its own can vibrate in any way. But once you put it in your guitar, it has a fixed length. You've imposed boundary conditions.

Like it can't vibrate at the points where it's tied down. And that limits the solutions to the wave equation. And quantum particles are governed by a different wave equation, the Schrodinger equation that tells us where its quantum wave function can exist and what solutions are allowed. And because you've put it essentially in a box, you've created boundary conditions, those limit the energy levels that it can be at. Right. So like an electron trapped kind of orbiting around a proton, like in the hydrogen atom,

can only do it in certain ways or configurations. And each one of those has a different energy level. Yeah, exactly. And something that's fascinating is that you just can't exist between those energy levels. Like if the Earth wanted to move into Mars's orbit, it could. You'd have to put a rocket on it and speed it up and do all sorts of stuff. And along the way, it would be sort of halfway between Earth's orbit and Mars's orbit. But electrons can't do that. They can't be in between. And yet they can be in one energy level at one moment and be in another energy level later on. Well, I think that's what Anna's question is asking is like, you're saying like an electron can only fit around a nucleus or a proton in certain modes or configurations.

But surely there might be some sort of transition period before it clicks into one of these. Like if I just throw an electron at a proton, you know, you're telling me there are some stable configurations, but as I throw it, doesn't it sort of exist in between these configurations? I think, ooh, that adds some complications. I think the simpler way to think about it is take an atom with an electron, a photon comes in with extra energy, the electron absorbs that photon, and now it's in a higher energy level. Does it take time to go from the lower energy level to the higher energy level? That's the question. Anna Khas, right? Yeah, that's the question Anik has exactly. But it's sort of the same

question as what I'm asking, which is like if I throw in an electron at a proton or it switches levels, doesn't it technically might take some time to go between the configurations? So the electron doesn't have to go from one configuration to another. Because

remember an electron doesn't have like a location at every moment the way the Earth does. The Earth is a classical object so it has a path, right? It has a location at every moment. And we think that that path is smooth. It's continuous. There's no instantaneous jumps in it. But electrons are not like that. They don't have a defined location at every moment. They don't have to go from one place to another to be at one place and later be at another place. You don't have to be able to track

its location at every intermediate spot for it to be somewhere and later be somewhere else. Right, because it's quantum mechanical, right? It's fuzzy. Yeah, exactly. But just because it's Fuzzy doesn't mean it can't be a weirdly shaped fuzzy in between the ones that click around the proton, can it? It can't be weirdly shaped fuzzy. Those solutions do not satisfy the mathematics, right? So they just cannot be in between. They don't satisfy the mathematics for them to be stable orbits, but can it exist in an unstable orbit or configuration for a moment? No, you really just can't do that as long as it stays bound, right?

As long as it's still within the atom, it's moving from one. energy level the atom to another, then there's no intermediate solutions. The way to think about it is not that the electron is in this state and then the electron is in that state. What happens is that the electron has a probability to be in the first state, call it 100%, and no probability to be in the higher state, so 0%. And then that probability can change. That probably changes smoothly so that at some moment the electron has a 50% chance of being in the lower state and a 50% chance of being in the higher state. And then later on, it'll have a 100% chance of being in the higher state and a 0% chance

of being in the lower state. So it's probability changes. And that actually changes smoothly. But which state is actually in, you can only ever measure it in one state or another. Right, because those are the stable solutions. But maybe, I guess maybe I wonder what Anik is asking is, you know, as those probabilities transition, can those take time maybe? Yeah.

So the probability transition does take time. absolutely, though you can only ever measure it in one state or another. So it does maybe take time for an electron to switch energy levels? Yes, absolutely. It takes time for that quantum state to transition. Nothing happens instantaneously in a relativistic world. But you'll never see the electron in between, right? What's happening is the probability to be in the lower state or the higher state,

those things are changing. It's sort of like if you have a coin, a coin you can flip it and get heads or tails. And what if I have like a little dial that changes the probability of heads or tails? So I start out with only going to flip heads and then I can turn that knob. So now it's 50-50 and then later on it'll only read tails. When you flip it, you'll always get heads or tails. Just the probability of heads or tails will change over time. But I guess maybe it depends on what you call like an energy,

an electron being in a certain energy state, right? Like what you call it being in an energy state is the probability of it being in an energy state and you're saying that the transition between probabilities is smooth and takes time. Then it does sort of technically take time for an electron to. switch between energy states. Yes, absolutely. There's like a moment when you can describe it as 50% in the lower state and 50% in the higher state.

That doesn't mean that it's like physical locations in between the two or you could ever measure it at any intermediate state, right? But there is a moment when it has a probability of being in the lower state or the higher state. Well, at the particle quantum level, my understanding is that things aren't really there anyways. There's just a probability of things to be there. Yeah, exactly. So the changing of its fuzziness from one shape to the other you're saying does take time.

Yeah, exactly. And so if you're thinking about it in that quantum mechanical way, it all makes sense. I wonder about Onyx question because I wonder if Onick is wondering if the electron like teleports from one place to another instantaneously. And so I just want to make sure that Onick and everybody listening understands that the electron doesn't have like an existing location has an energy level, which is a probability distribution and that transitions to a new probability distribution. It's not like the electron is here and then it reappears instantaneously in another orbit. Right. Well, I think maybe the way that most physicists like to draw these orbits is as clouds, right? Like probability clouds.

And you're saying like a cloud can't just convert from one shape to another cloud. There has to be this transition period where it's like maybe a little bit of both, in which case the blob looks a different shape. Yeah, exactly. One blob is decreasing while another blob is increasing. There's no intermediate blob. Right. Well, if you add up the two, don't it? Doesn't that happen? Yeah, exactly. The intermediate blob is just different mixtures of the two.

Right, which would have its own shape. Yeah, which has its own shape. Okay, so maybe like don't think of it as the electron jumping from one orbit to another. Think of it just as like one electron changing from being a blobby shape that looks like this to the different blobby shape in the quantum world that looks like that. And that does take time, you're saying. Like how much time? It depends on the energy.

And it's actually a fascinating little wrinkle in quantum mechanics because the Schrodinger equation is not relativistic. It doesn't like respect special relativity and have the speed of light built into it. You have to add that in when you get to like relativistic quantum mechanics or quantum field theory. But there are still some guardrails there that prevent things from happening instantaneously. Like it's a wave function and waves evolve smoothly with time. And because it's a wave, and it's wave nature is what generates the Heisenberg uncertainty relationships. So in this case, for example, there's a relationship between energy and time.

If you want something to happen really, really fast, like almost instantaneously, then the energy of that process is very uncertain. If you want something to be really specific about energy, then the time is uncertain. Essentially, it can take a very long time. So you can have something that happen really fast, but then you can't be certain about the energy of it. Or you can have something happen with a really specific energy, but then you can't really be sure it's going to be fast. So you can't have something happen really fast and to a very specific energy at the same time. Yeah, it seems like it's maybe one of those things we talked about in a previous podcast about what the uncertainty in quantum mechanics actually means.

Yeah. Okay, so then what's the answer? How fast is it changing or can it change? You're saying they can change instantaneously if you put infinite amount of energy into it? If you have an infinite uncertainty in your energy, then yes, you can approach an instantaneous transition. But then you have no idea what transition you're going to. You're going from energy level one to energy level unknown. well maybe give us a second since you're a particle physicist when you smash these particles together

and they're interacting at the quantum level like how fast are these reactions happening or these transformations or these you know breaking up of particles it's like nanoseconds right or less oh yeah much faster than that yeah we're talking about events that like 10 to the minus 23 seconds so super short periods of time and in this case you can measure those things or is it kind of theoretical. Can you see? Can you measure? Can you clock something happening that fast? Or you just think it's happening that fast? We can make sure those measurements, but it's sort of indirect. Like the time that a particle survives depends on its energy and its mass and the uncertainty in its mass. So by measuring like the uncertainty in the mass of a bunch of particles, we can measure how long effectively those

particles are living. So for example, we measure the top quark mass really, really precisely. And we know the variation from top cork to top cork. And that tells us how long the top corks live. But it's one or two steps indirect from like actually looking at a clock and seeing it tick by. But you do seem to have some numbers for it. So in the case of the electron, what kind of number would you put on it? Like in our everyday lives, you know, a ray of light hits my skin. How long are my electrons and my skin changing energy states? So the energy levels of the hygiene atom, I happen to know because my son is doing chemistry, are like 13.6. 6 EV, so call it like 10 electron volts.

And the uncertain relationship is dominated by Planck's constant, which is like 10 to the minus 15 EV seconds. And so put that together and it tells you that we're talking about transitions of the order of like 10 to the minus 15 seconds. Whoa, which seems slower than the ones when you smash particles. Yeah, but still pretty fast. All right. Well, I think that answers annex question.

It does take some time for the electron to jump between energy levels, maybe to the order of 10 to the minus 15 seconds. All right, let's get to our last question. But first, let's 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. 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. 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. Hola, it's Honey German, and my podcast, Grasasas Come Again, is back. This season, we're going even deeper into the world of music and entertainment,

with raw and honest conversations with some of your favorite Latin artists and celebrities. You didn't have to audition? No, I didn't audition. I haven't auditioned in, like, over 25 years. Oh, wow. That's a real G-talk right there. Oh, yeah. We've got some of the biggest actors, musicians, content creators, and culture shifters

sharing their real stories of failure and success. You were destined to be a start. We talk all about what's viral and trending with a little bit of chisement, a lot of laughs, and those amazing vizras you've come to expect. And of course, we'll explore deeper topics dealing with identity, struggles, and all the issues affecting our Latin community. You feel like you get a little whitewash because you have to do the, code switching?

I won't say white wash because at the end of the day I'm me. But the whole pretending and cold, you know, it takes a toll on you. Listen to the new season of Grasas Come Again

as part of My Cultura Podcast Network on the IHartRadio app, Apple Podcast, or wherever you get your podcast. A foot washed up a shoe with some bones in it. They had no idea who it was.

Most everything was burned up pretty good from the fire that not a whole lot was salvageable. These are the coldest of cold cases. But everything is about to change. Every case that is a cold case that has DNA. Right now in a backlog will be identified in our lifetime. A small lab in Texas is cracking the code on DNA.

Using new scientific tools, they're finding clues in evidence so tiny you might just miss it. He never thought he was going to get caught. And I just looked at my computer screen. I was just like, ah, gotcha. On America's crime lab, we'll learn about victims and survivors. And you'll meet the team behind the scenes at Othrum, the Houston Lab that takes on the most hopeless cases to finally solve the unsolvable. Listen to America's Crime Lab on the IHeart Radio app, Apple Podcasts, or wherever you get your podcasts.

We're answering listener questions. And our last question here today has to do. with polarization. Not of our country, but of light. Exactly. Hi, Daniel and George. I'm Vivek from Brisbane. If you could answer my question on polarization at quantum level, that would be really good.

You have a great broadcast. What the polarization is at photon level? Does the photon vibrate? in all planes and polarization allows only in a specific plane or a photon vibrates only in one plane and polarization allows photons which align with that polarization plane. Thank you. All right.

I think Vivek's question in general is basically like what is polarization? What's going on at the photon level? What does it mean for a photon or a light wave to have polarization? because polarization is sort of all around this right as sunglasses are polarized some of them definitely the screen on your phones are polarized and so it's something that actually affects us every day yeah polarization is really fascinating and tricky to think about and i find a lot of listeners are confused on some basic concepts of like the mental picture they have of what a photon looks like is usually wrong so i thought it'd be fun to talk first about what is polarization

for classical electrodynamics and then we can talk about what it looks like for a photon Okay. Now, this is a property that light has, right? Like, light can be polarized. Yeah, exactly. Light can be polarized. So what is it? So if you think of light as just like a wiggle in the electromagnetic field, let's just ignore quantum effects for now. Let's pretend that we're Maxwell and we're just thinking about light as like oscillations in electric and magnetic fields, right? Meaning like basically all around us is an electromagnetic field. Like we're all surrounded by this field.

Exactly. And the light ray is just kind of like a wiggle in that field that zooms across the room. Exactly. And there's an electric field and there's a magnetic field. And they're sort of on top of each other. A field is something that exists in all of space. Right. And so there's an electric field and there's magnetic fields all through space. And a light wave. They're different. They are different. They're two components of something larger. We call the electromagnetic field, but they're different. Like the way two sides of a coin are different but connected. And a light wave is an oscillation in these two fields that are linked. This is like Maxwell's greatest insight to show that electric fields and magnetic fields. fields are really tightly coupled. One can generate the other. So like a light ray is a wiggle in one of these fields, but it's actually, the two fields you're saying are sort of like connected to each other. So you can't just have a wiggle in one field. It has to come with a wiggle in the other field. Exactly. Because changing electric fields will give you magnetic fields and changing magnetic

fields will give electric fields. So it's a coupled oscillation. It's like sloshing back and forth between them. Okay. So we're surrounded by fields. A light ray is a wiggle in that field. So what's its polarization? So the crucial thing to understand is that these fields are not just numbers. They're a vector, which means that at every point in space, these fields don't just have a value. They have a direction, like a tiny little arrow. That's what's really interesting about the electromagnetic fields, not just like a number through space. It's a little arrow.

Meaning it's not just like an intensity at any given point or like a brightness to it. It's also like it has a directional component to it. Exactly. It has a directional component to it. Like you can have a wiggle that's pointing up or a wiggle that's pointing down or to the sides. And light is an oscillation of those little arrows. And people often think that, oh, a light wave is like literally moving side to side as it moves through the universe. That it's wiggling sideways.

But it's not. A light wave is moving along a straight line. What's wiggling sideways is the vector of the electric field and the vector of the magnetic field. So along a straight line, you have like an arrow that's growing and shrinking and growing and shrinking. Pointing at what direction? Those arrows are pointed perpendicular to the motion of this wave because light is a transverse wave. So you're saying a photon is like you can imagine it like a little bead

going along a string from here. Like if I shoot a laser I do, we can trace. It's like a little bead that's going on a string from me to you. But as it's going down the string, it has kind of like arrows shooting out of it. Exactly. To the sides and up and down. But it never moves sideways, right? It's always along that bead.

What's moving sideways is the strength of these little arrows, the electric field and the magnetic field. And polarization is telling you where those fields are pointing. So the electric field is pointing perpendicular to the motion of the photon, but there's still lots of ways that it could point. There's a whole circle of directions it could point. Polarization is telling you which direction is the electric field pointing as the photon moves along that line. So as it moves, like maybe you can have an electric field that's pointing up and it wiggles by shrinking and growing in the up direction. Yeah, exactly.

Or sideways. Now, does a photon have to have a direction? Can you have a photon that's like what, what does it mean to have a photon that's not polarized? So an individual photon has to have a direction. You can have a beam of light that's unpolarized. That means that it's a big mixture of photons of lots of different polarizations. So you can't have an unpolarized photon. Each photon by definition is polarized.

Exactly. And now we're mixing sort of the classical and the quantum. version. The classical version is that these are just waves in the field. There are no photons. Brighter light means just like bigger wiggles in the field. The quantum version says, no, no, no. It comes in discrete packets.

Each one is its own photon. Brighter light is more photons. And so in the quantum version, this still happens, but now you have quantum spin instead of like the direction of the electric field. But still, you can't have an individual photon that's unpolarized. Every photon has a direction, either to its quantum spin, spin or to its classical electric field.

And the polarization tells you what direction that's in. Right. Like each photon, you're kind of saying has it like an kind of like an up and down and a left and right. And so its polarization is kind of like, uh, in what direction is it up and down pointing? Yeah, exactly. Like firefighters sliding down a pole, right? They can slide down in lots of different angles.

They're moving down the pole always, but they can slide down facing left or facing right or facing any angles. It's like the polarization of the firefighter. So the same way, photons move. moving in the same direction can have a different polarization and still be moving in the same direction. So then that's basically what polarization is. It's like the direction in which its electric field is pointing it as it wiggles.

Exactly. For classical electrodynamics, it's the direction of the electric field. For quantum photon, it's the direction of its quantum spin. Interesting. Now, when it comes to sort of like our everyday experience, you're saying that polarized light is one in which all the photons are basically pointing in the same. direction and unpolarized light is where all the photons are like pointing they're all pointing in random directions exactly it's not really unpolarized it's a sum of different polarizations

it's like you have a bunch of people with different political opinions it's not like you have no politics you just have lots of different politics it's like multipolarized you're saying unpolarized you're really saying multipolarize exactly and you can have polarization filters for example that only allow a certain polarization through where you can only allow light through that's like going up and down or only allows light through that's going side to side with this polarization. Now, the light from my cell phone, like the screen, I know that light is, like coming from the screen is polarized. Now, is that polarized because there's a filter in the glass of my cell phone or because the, you know, whatever diodes or something that's generating the light

somehow only produce a certain kind of photon? Yeah, I have no idea. All right. You're not even going to try to circumvent the question? let's see your crafted work if I asked you why myself when has polarized light Daniel what would you say and you can't cut this out later I don't know

I don't know I don't know the answer is I don't know meaning you Wikipedia this late it's possible that your phone screen filters it out or it's possible that it's generated in such a way to only be polarized

I think they do that because it's easier to look at but I'm not sure interesting all right well maybe we'll leave this as homework for listeners to try to look it up.

All right, but the answer to the basic question, that's kind of what polarization is. You're saying it's a direction of the wiggles of a photon in the electric field and magnetic field. Yeah, exactly. And remember that the photon itself is not wiggling in space. It never deviates from the line of its motion. What's wiggling there are the electric and magnetic fields

for the classical picture. In the quantum picture, the photon's still moving just along that line and now the polarization is describing the direction of its quantum spin. Right. Although it's sort of like these are quantum objects, right? So you can't really say that it's staying in the middle. You're just mathematically, that's where you assume that it's staying on. Yeah, exactly.

They have no path and no definitive location. But if you're solving the equation for where it's likely to be, then that's a long line. Right. So it is sort of maybe wiggling in actuality. You just mathematically, it doesn't deviate on average. Yeah, there's definitely a fuzziness to a photon's location, but not an oscillatory way. All right. Well, those have been three awesome questions.

Do you think everyone deserves a lollipop? I feel like I deserve one. Yeah, I think a bowling ball-flavored lollipop would really finish this off. Oh, my gosh. Yeah, yeah, yeah. But you have to be careful, though. You have to make sure it is a lollipop. You don't want to be licking any random bowling balls.

You don't know where those have been. Or billion balls. Maybe a billion bars would be even worse. Just don't lick stuff. That's the health advice from your physics podcast. Unless you're absolutely sure. I guess you could test it on your dog, maybe, or on a physicist. And if you do look stuff, don't sue us over it, please.

Yeah, unless you liked it. That's a whole different kind of podcast, Jorge. Well, as usual, another reminder that we can still ask a lot of questions about the universe. There's still a lot of mysteries to think about, to explore. And sometimes you can even stump the physicist to the point where they say, I don't know. We say that all the time. How often do you say it, Daniel? I don't know.

There you go. There you go. That's the exact answer I was looking for. And if there's things that make you go, I don't know, then write to me and I'll talk to you about it. I'll tell you everything I do and don't know about the subject. The email address is Questions at Danielanhorpe.com, and we love to hear from you.

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. For more podcasts from IHeartRadio, visit the IHeartRadio app, Apple Podcasts, or wherever you listen to your favorite shows. Come on, why is this taking so long?

This thing is ancient. Still using yesterday's tech, upgrade to the ThinkPad X1 Carbon, ultra-light, ultra-powerful, and built for serious productivity, with Intel Core Ultra processors, blazing speed, and AI-powered performance. It keeps up with your business, not the other way around. Whoa, this thing moves. Stop hitting snooze on new tech. Win the tech search at Lenovo.com.

Unlock AI experiences with the ThinkPad X1 Carbon, powered by Intel Core Alter processors so you can work, create, and boost productivity all on one device. 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.

of enemy emerged. Terrorism. 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. Wait a minute, Sam. Maybe her boyfriend's just looking for extra credit. Well, Dakota, luckily, it's back to school week on the OK Storytime podcast, so we'll find out soon. This person writes, my boyfriend's 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. 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. This is an IHeart podcast.