Speaker 1: One of my favorite things about physics is that it
Speaker 1: lets us think concretely and carefully about the basic nature
Speaker 1: of our experience. What is space? What is matter? What
Speaker 1: is time? What's a particle? Why are there waves everywhere?
Speaker 1: Physics helps us convert these squishy conversations on rooftops over
Speaker 1: smoke banana peels into robust mathematics. The math doesn't require
Speaker 1: persuasion or a clever choice of words. It's either right
Speaker 1: or it's wrong. So instead of answering a question about
Speaker 1: the nature of the squish universe, we get to poke
Speaker 1: and prod our mathematical description of it. Sometimes that gives
Speaker 1: us real insight, like when relativity tells us that distance
Speaker 1: and velocity have to be relative rather than absolute, because
Speaker 1: that's the only mathematical model that describes the universe we see.
Speaker 1: Other times it surprises us by telling us that we
Speaker 1: might just be asking the wrong question. Maybe the things
Speaker 1: we thought were important just reveal our fundamental misunderstandings of
Speaker 1: the universe and how it works. Today we'll be asking
Speaker 1: what physics can tell us about energy, What is it?
Speaker 1: And more importantly, where does it come from? Welcome to
Speaker 1: Daniel and Kelly's Extraordinary energetic Universe.
Speaker 2: Hello. I'm Kelly Wiener Smith.
Speaker 3: I study space and parasites and I just got over
Speaker 3: having the flu for a week and I really could
Speaker 3: have used energy.
Speaker 1: Hi. I'm Daniel. I'm a particle physicist and I love
Speaker 1: how Kelly opens the podcast with so much energy every time.
Speaker 2: Okay, well we both have a lot of energy.
Speaker 3: Speaking of energy, do you rely on caffeine? What is
Speaker 3: your favorite form of liquid energy?
Speaker 1: I do rely on caffeine. I'm drinking coffee right now here.
Speaker 1: You go, Oh oh for you asmr. Folks. Yeah, yes,
Speaker 1: I have caffeine in the mornings, but I can't have
Speaker 1: any really after lunch or interference with my sleep. I'm
Speaker 1: at that age where sleep is not necessarily a given.
Speaker 2: Yeah. Same.
Speaker 3: I used to drink coffee all day long. I like
Speaker 3: didn't drink water in college.
Speaker 1: That doesn't sound like a good idea.
Speaker 3: You know, I got a lot done, I got a
Speaker 3: whole lot done, but I could still fall asleep. But
Speaker 3: now I also if it's after lunch, forget it. I
Speaker 3: can't have coffee anymore either.
Speaker 1: Remember, folks, this is not a health podcast. Do not
Speaker 1: take our advice.
Speaker 3: Noah, no, please don't don't follow our lead. When you
Speaker 3: were a kid, did you ever try jolts?
Speaker 1: Jolt was the kind of thing that was so forbidden
Speaker 1: in my family. Like my mom was very controlling about
Speaker 1: the kind of food we could eat, you know, she
Speaker 1: like counted potato chips, this kind of thing, So junk
Speaker 1: food definitely off of this jolt. She saw that as
Speaker 1: like battery acid, Like there was no way she would
Speaker 1: allow us. Did you try jolts?
Speaker 2: Yeah? Do you remember pixie stick?
Speaker 1: Yeah?
Speaker 3: So there used to be like a megapixie stick. It
Speaker 3: was like a giant plastic tube like the thickness of
Speaker 3: my thumb, and it was just filled with.
Speaker 2: Sugar and food coloring.
Speaker 3: And we had like a party once where we just
Speaker 3: like had those pixie sticks with jolts.
Speaker 2: And I got pretty sick.
Speaker 3: And jolts made me feel horrible the way too much
Speaker 3: caffeine makes me feel now.
Speaker 2: But I tried it once, and it was one thing
Speaker 2: as a kid.
Speaker 3: Where I was like, I shouldn't do that again. Anyway,
Speaker 3: I had a lot more fun.
Speaker 1: It sounds like it does sound like you had more fun,
Speaker 1: but you also got sick. But I have a basic
Speaker 1: biology question for you about caffeine. I mean, I understand
Speaker 1: if you eat a pixie stick, it's sugar. Sugar has energy.
Speaker 1: You could potentially get high and a rush and feel
Speaker 1: energetic from that. But caffeine, how does that give me
Speaker 1: energy or make me alert? Is it really energy from
Speaker 1: the caffeine that my body's using. Is it releasing some
Speaker 1: energy stores in my body? Or is it some much
Speaker 1: more complicated neuro answer, dot dot dot. It depends.
Speaker 2: Probably, it depends. I don't actually know.
Speaker 3: I didn't prepare the answer for that coming in here.
Speaker 3: I believe it binds to certain receptors in your brain.
Speaker 3: My job in college was barista. I worked at like
Speaker 3: four different coffee shops, and so I've had like shirts
Speaker 3: with the caffeine molecule on the front. So yeah, I
Speaker 3: think it binds with some receptors in your brain. And
Speaker 3: I don't know how that results in you feeling awake,
Speaker 3: but it works.
Speaker 1: It pulls on some levers and ropes of the Rube
Speaker 1: Goldberg machine that is my mind.
Speaker 3: That's right, that's right, and thank God for it. I
Speaker 3: don't know how I would have gotten through college without it.
Speaker 3: At some point I was working at a coffee shop
Speaker 3: because I couldn't afford all the coffee I wanted to drink,
Speaker 3: but if I worked at the coffee shop, I could
Speaker 3: afford it and pay my rent. So anyway, I had
Speaker 3: a problem maybe, but I also had fun.
Speaker 1: Well. Energy is a really fun topic because it's something
Speaker 1: that is colloquial and we talk about it in our
Speaker 1: lives and whether you feel energetic and whether you drink
Speaker 1: caffeine whatever, And it's also something deeply important to physics
Speaker 1: and the universe. So it's one of these topics that
Speaker 1: people have like a personal feeling about, like where energy is,
Speaker 1: where it comes from, and what it means. And it's
Speaker 1: also really pervasive in popular science. You know, equals MC squared,
Speaker 1: energy is mass. People tell us there's a lot of
Speaker 1: nonsense out there about energy. So I thought it'd be
Speaker 1: good to have an episode where we dig into some
Speaker 1: details about what energy is and where it comes from
Speaker 1: and what we know and don't know about it.
Speaker 3: Yes, and you always do a great job of getting
Speaker 3: us back on tracks. That was fantastic, and the other
Speaker 3: people who keep us on track are our amazing audience,
Speaker 3: and so we asked them where does energy come from?
Speaker 3: And if you want to answer questions for us, you
Speaker 3: can write us at questions at Daniel and Kelly dot org.
Speaker 3: But let's go ahead and here from our audience, where
Speaker 3: does energy come from?
Speaker 1: Energy comes from heat, which comes from photon. I have
Speaker 1: no idea.
Speaker 4: Is it a mathematical trick, is it just an accounting system?
Speaker 1: Who else? Nobody knows where energy comes from, and nobody's
Speaker 1: ever gonna know. It is the magic of the universe.
Speaker 5: I don't think energy comes from anyway, because you can't
Speaker 5: have not energy.
Speaker 1: Well, it comes from fields that permeate the entire universe.
Speaker 1: Energy comes from hydrogen fusion caused by gravity, So I'd
Speaker 1: have to say gravity.
Speaker 4: Yes, it comes from the Big Bang and has just
Speaker 4: been circulating in different forms ever since. Or powered Now,
Speaker 4: if you're talking about the energy that powered the Big Bang,
Speaker 4: or energy required to keep all the quantum fuels fluctuating
Speaker 4: and alive, I imagine a physicist is better suited to
Speaker 4: provide insight.
Speaker 1: Hint, hint, So I guess that MLGS comes from symmetries
Speaker 1: in nature. Obviously the Big Bang has a big role
Speaker 1: in it, but it might not be the whole thought.
Speaker 6: Since you can't create energy, I assume it originates from
Speaker 6: the Big Bang, and before then who knows.
Speaker 1: I guess it's always better around.
Speaker 6: It just changes form after form.
Speaker 1: Perhaps what we're calling space time is actually energy. Oh well,
Speaker 1: I really am stumped by this one. I really don't know.
Speaker 1: All the energy in the universe today came from the
Speaker 1: storehouse of energy released in the Big Bang.
Speaker 5: Some energy comes from the Big Bang, and some comes
Speaker 5: from dark energy, but most energy in this universe comes
Speaker 5: from eating your waities.
Speaker 6: Have we not always had the same amount of energy?
Speaker 5: I would say all energy originated from the Big Bang
Speaker 5: and everything since then it's just been conversions of different forms.
Speaker 5: But then you can ask where did that come from?
Speaker 5: And where does dark energy come from?
Speaker 1: And I don't know. There's some really philosophical answers in here,
Speaker 1: and I loved listening to these.
Speaker 2: Well, I mean, that's what I've come to expect from
Speaker 2: the audience.
Speaker 3: It's like always a nice combination of like philosophical some
Speaker 3: people who get like exactly the right answer or get
Speaker 3: really close, and then some people who know they don't
Speaker 3: know and so they.
Speaker 2: Just go all in on being hilarious.
Speaker 3: I always love listening to the answers.
Speaker 1: This comment that you can't have not energy, I had
Speaker 1: to pause that and think about it for a while.
Speaker 1: I was like, Wow, that sounds really profound, but I'm
Speaker 1: not even share what it means.
Speaker 3: Like a lot of philosophy, I thought that they were
Speaker 3: trying to say, if there wasn't energy, none of us
Speaker 3: would be here, which doesn't really the answer the question
Speaker 3: where it comes from, but just something had to have
Speaker 3: made it exist.
Speaker 2: I don't know, what do you think?
Speaker 1: I didn't know? Yeah, what is not energy? Is that
Speaker 1: energy equals zero. It's true, you can't have zero energy
Speaker 1: in the universe because of quantum mechanics. Yeah, fascinating, Yeah,
Speaker 1: really fun answers here and a lot of assumptions. You
Speaker 1: hear that energy doesn't come from anywhere because we've had
Speaker 1: the same amount the whole time. Because people have this
Speaker 1: conception which we're going to take apart and debunk a
Speaker 1: little bit, that energy is conserved. The energy has to
Speaker 1: come from somewhere because you can either create nor destroy it,
Speaker 1: and therefore it can only flow.
Speaker 3: So yeah, when I was looking through your outline and
Speaker 3: I saw energy is not conserved, I was like, what,
Speaker 3: I'm sure I've heard that a lot of times, and so,
Speaker 3: you know, I think a lot of us are looking
Speaker 3: forward to having our preconceptions about energy sort of cleared up.
Speaker 1: Yeah, exactly. But before we get into the mind blowing
Speaker 1: revelations about the nature of energy, we have to be
Speaker 1: clear and careful about what is it we're talking about anyway.
Speaker 1: Are we talking about how the earth keeps warm? Are
Speaker 1: we talking about what happens when you eat your wheaties?
Speaker 1: Are we talking about philosophical revelations about the fundamental nature
Speaker 1: of the universe. So the first thing we have to do,
Speaker 1: of course, is define what do we mean when we
Speaker 1: say energy.
Speaker 3: Yeah, so as a biologist, I'm thinking ATP, I'm thinking
Speaker 3: at it at a chemistry level. We're as a physicist.
Speaker 3: Do you think about it like that as well? Or
Speaker 3: this is just a totally different topic.
Speaker 1: Now ATP is like a chemical store of energy, so
Speaker 1: it's completely related to the topic at hand. But it's
Speaker 1: an example, right. It's like if somebody says to you, hey,
Speaker 1: what is a vegetable and you're like, an implant is
Speaker 1: a vegetable, And you're like, yeah, that's true, but what
Speaker 1: makes it vegetable? Why do we have them? Where do
Speaker 1: vegetables come from? Right? Showing you an a plant doesn't
Speaker 1: answer that question.
Speaker 3: Right, and then I'll go on a long rant about
Speaker 3: how vegetables not a phylogenetic category and it's something humans
Speaker 3: made up, and so anyway, go ahead.
Speaker 1: Oh my gosh, wow, oh I love when we accidentally
Speaker 1: stumble up upon a hidden Kelly rant. Love that. Wow.
Speaker 3: Okay, let's go deeper, hurt, but not on vegetables. So
Speaker 3: what is energy? How does a physicist start to answer
Speaker 3: this question?
Speaker 1: I like to answer this question by pointing out that
Speaker 1: we can invent any kind of concept. I mean, you
Speaker 1: can just make up a word called it, you know,
Speaker 1: bliblyon or whatever, and then define it and it could
Speaker 1: be a thing. And the question is like, does that
Speaker 1: reveal anything about the universe? Is it related to the
Speaker 1: physical universe in some insightful way, or is it just
Speaker 1: some nonsense that you made up? And so, from that
Speaker 1: point of view, like everything in physics is something we
Speaker 1: made up, and a lot of it is just nonsense
Speaker 1: we then ignore because it wasn't useful. And some of
Speaker 1: it actually seems to reflect something that's happening in the
Speaker 1: universe and is therefore useful, and we think maybe in
Speaker 1: delightful about the fundamental nature of reality. Right, And so
Speaker 1: energy is that way. It is something we invented. It's
Speaker 1: just like a concept we came up with. We talked
Speaker 1: recently on the podcast about entropy and the history of
Speaker 1: energy is similar predates entropy because entropy was defined as
Speaker 1: moving of energy the een and entropy comes from energy.
Speaker 1: But this is something people have been wondering about it
Speaker 1: for a long time, like how do you get a
Speaker 1: machine to work? And what's going on with heat a temperature?
Speaker 1: And so people came up with this concept of energy
Speaker 1: one hundreds of years ago. It was actually leading It's
Speaker 1: first identified energy of motion, like things in motion have energy,
Speaker 1: and he called it this visviva, this living force, just
Speaker 1: energy of motion. He recognized that.
Speaker 3: That was like a thing, but like an asteroid hurtling
Speaker 3: towards the Earth would have energy. But in what way
Speaker 3: is that a living force? Was he like specifically thinking
Speaker 3: about living organism.
Speaker 1: No, he was just thinking about animation, not necessarily like
Speaker 1: something is alive, but in motion. And so I think
Speaker 1: he was thinking more about the motion than the actual
Speaker 1: life force or the definition of life in some sort
Speaker 1: of biological way. But that's something we still recognize, right.
Speaker 1: We call that kinetic energy today and kinetic energy is
Speaker 1: definitely a form of energy, like photons have energy, right,
Speaker 1: they zoom around the universe. They're moving really really fast,
Speaker 1: So it's a type of energy. But again, this is
Speaker 1: like quoting the eggplant, right, it's not a definition of
Speaker 1: the concept. It's an example of the kind of thing,
Speaker 1: and it comes from history. And something that's especially fascinating
Speaker 1: and revealing about kinetic energy is that it's not conserved. Right.
Speaker 1: For example, you throw a ball up into the air,
Speaker 1: it slows down, right because of gravity. If you throw
Speaker 1: it straight up, it slows down, and eventually, when it
Speaker 1: reaches the top of its arc, its stopped. So kinetic
Speaker 1: energy on its own is not something that's conserved in
Speaker 1: the universe, Like the universe doesn't seem to have a
Speaker 1: special relationship with kinetic energy. It's the way you could
Speaker 1: make up any other thing, like, hey, how many ice
Speaker 1: cream cones are there currently in the universe. That's a
Speaker 1: number that we don't expect to stay constant. Right, I
Speaker 1: eat one, it's gone. I've decreased the number. I make one,
Speaker 1: it goes up. Kelly makes five thousand ice cream cones,
Speaker 1: it goes up a lot. Right, It's not anything meaningful
Speaker 1: or specific and kinetic energy is sort of the same way.
Speaker 1: Like when the ball gets thrown up into the air,
Speaker 1: it loses that kinetic energy. Where does the kinetic energy go. Well,
Speaker 1: energy can just go up and down. In this case,
Speaker 1: we know it actually transforms into another kind of energy
Speaker 1: we call potential energy, because now that ball has gained altitude,
Speaker 1: which means it's moved up in the gravitational field, and
Speaker 1: so it's imbued now with something we call potential energy.
Speaker 1: And so now we have two kinds of energy kinetic energy,
Speaker 1: energy of motion, and potential energy, which is energy of
Speaker 1: position or arrangement.
Speaker 3: Okay, do all different kinds of energy have the same units?
Speaker 1: Yes?
Speaker 2: Units, help me think about scientific phenomena.
Speaker 1: Yes, all energy has the same unit. So you can
Speaker 1: use jewels, for example, as a unit of energy, and
Speaker 1: kinetic energy can be calculated in jewels, and potential energy
Speaker 1: also calculated in jewels, and you can go back and forth. Right,
Speaker 1: if you're standing on the top of a building, you
Speaker 1: have a lot of potential energy because you're high up,
Speaker 1: you have a lot of altitude, and you jump off
Speaker 1: that building. You turn that potential energy into kinetic energy
Speaker 1: because by the time you get to the bottom of
Speaker 1: the building. You no longer have the altitude, so you
Speaker 1: have no potential energy, and you have a lot of velocity. Right,
Speaker 1: So you've turned potential energy into kinetic energy. And you
Speaker 1: roll a ball up a hill, or you throw a
Speaker 1: ball up in the air, kinetic energy turns into potential energy.
Speaker 1: And the same thing is true for example, like a spring.
Speaker 1: A spring is a way to store potential energy. And
Speaker 1: if you push on a spring and then you let
Speaker 1: it go, it will oscillate back and forth and back
Speaker 1: and forth. And what's happening there is it's slashing kinetic
Speaker 1: energy into potential energy, back into kinetic energy, back into
Speaker 1: potential energy. So you know, like a simple model of
Speaker 1: you have a block of stone on a spring, it'll
Speaker 1: just sit there oscillating back and forth if there's no friction,
Speaker 1: turning kinetic and potential energy back and forth into each other.
Speaker 1: Which is also a really helpful way of thinking about
Speaker 1: waves in general. Like whenever we're talking about fields oscillating,
Speaker 1: even quantum fields, that's what's happening is that they're sloshing
Speaker 1: back and forth between different kinds of energy. And so
Speaker 1: now we go from having just kinetic energy energy of
Speaker 1: motion to having two kinds of energy, which, if there's
Speaker 1: no friction, do appear to conserve the total energy. So
Speaker 1: kinetic energy not conserved, potential energy not conserved, but their
Speaker 1: combination in simple systems with no friction or irresistance or
Speaker 1: anything does seem to be conserved, which suggests that it's
Speaker 1: like something may be more important to the universe.
Speaker 3: Okay, all right, So for the examples that we've talked
Speaker 3: about so far, you've got like a ball rolling down
Speaker 3: a hill, or a ball being thrown up in the
Speaker 3: air or something that it seems like the energy for
Speaker 3: those activities came from the energy of the person who's
Speaker 3: making it happen. Is that an okay way to think
Speaker 3: about it? Both of those examples seem the energy is
Speaker 3: coming from the person who set the ball in motion.
Speaker 1: Or carried it originally to the top of the building
Speaker 1: and dropped it.
Speaker 3: Yeah, right, right, Okay, so we haven't really gotten to
Speaker 3: where energy came from because energy seems like it's coming
Speaker 3: from the person who started it.
Speaker 2: Is that a fair way to think about it?
Speaker 1: Yeah? I think that's fair. And there's something cool you
Speaker 1: can do there, which is sort of trace the path
Speaker 1: of the energy. Right, Like say the person threw the
Speaker 1: ball into the air, So you're right, it has potential
Speaker 1: energy which came from its kinetic energy, which came from
Speaker 1: the energy stored in that person's muscles, right, which converted
Speaker 1: some sort of chemical energy storage into the contraction of
Speaker 1: those muscle cells, which accelerated the ball. And that chemical
Speaker 1: energy storage came from something that person ate, right. And
Speaker 1: that thing the person ate probably grew and maybe it
Speaker 1: was an animal and ate plants, or maybe it was
Speaker 1: a plant directly and that grew somehow by drinking light
Speaker 1: from the sun. Right. And so you can play this
Speaker 1: game where you trace the energy back, and one of
Speaker 1: our listeners commented that a lot of the energy on
Speaker 1: Earth seems to come from the sun, which is true, right,
Speaker 1: There's like a little bit of a source of energy
Speaker 1: from inside the Earth, but most of the energy does
Speaker 1: come from the Sun. And playing this game tracing the
Speaker 1: energy back has inside of it an implicit assumption that
Speaker 1: you can trace energy because again, it has to come
Speaker 1: from somewhere because it's conserved. It doesn't just disappear and
Speaker 1: it doesn't appear. And again I'm not saying that energy
Speaker 1: is conserved. I'm saying that if energy were conserved, then
Speaker 1: you can play this game, which is really fascinating because
Speaker 1: it allows you to like, you know, sort of rewind
Speaker 1: the accounting of the universe, and it is kind of
Speaker 1: mind blowing to realize that, like, wow, almost all the
Speaker 1: energy that we use here on Earth was originally created
Speaker 1: in the sun by fusion and then gobbled up by plants.
Speaker 3: All right, let's take a break, and when we come back,
Speaker 3: we are going to dig into whether or not mass
Speaker 3: could be considered a kind of energy.
Speaker 2: All right, we're back.
Speaker 3: So before the break, we were talking about how a
Speaker 3: lot of energy on Earth comes from the Sun, and
Speaker 3: so I'm thinking about you know, plants growing, putting on
Speaker 3: mass as you know, their chloroplasts, or turning energy from
Speaker 3: the Sun into energy for them, and then I eat
Speaker 3: them and put on a little bit of mass, just
Speaker 3: a little and use that energy to make a lot
Speaker 3: of ice cream cones, which makes people very happy. Should
Speaker 3: I think about mass as a third kind of energy.
Speaker 1: It's tempting, right to think about mass and another kind
Speaker 1: of energy, because we talked about stored energy, chemical energy,
Speaker 1: and atp energy stored in protons as they get fused
Speaker 1: together in the sun. And you hear a lot that
Speaker 1: mass is another kind of energy. People say equals mc squared, right,
Speaker 1: and so therefore mass is energy and energy is mass. Yeah,
Speaker 1: so that's not really true, and the deeper answer is
Speaker 1: that mass is just an indicator of internal stored energy.
Speaker 1: Think about some object and you can categorize all of
Speaker 1: its energy into two different boxes. One is the motion
Speaker 1: of that object, like, is the whole thing moving? If so,
Speaker 1: it's got some kinetic energy, right. Cool. The other kind
Speaker 1: of energy you can have is internal energy, like maybe
Speaker 1: there's a bunch of particles and they have bonds, or
Speaker 1: there's chemistry or something. All that internal stored energy is
Speaker 1: what we call mass. Mass is not a new form
Speaker 1: of energy. It's not a special kind of energy on
Speaker 1: its own. It's an indicator of how much energy is
Speaker 1: stored inside something.
Speaker 3: Okay, So like if you've got a big truck and
Speaker 3: a little truck and you set both of them going
Speaker 3: down the hill, the big truck is going to have
Speaker 3: more energy because it has more mass, and it's an
Speaker 3: indicator that it has more energy.
Speaker 1: But it's yeah, exactly, if you measure the inertia of
Speaker 1: something right by giving it a push, you give something
Speaker 1: a certain amount of and then you measure its acceleration.
Speaker 1: That tells you it's inertia because F equalsma. Then what
Speaker 1: you're really measuring is how much energy is stored inside something.
Speaker 1: And you can make this very concrete, like take a
Speaker 1: rock that has a certain mass, shoot a photon at it.
Speaker 1: What happens. The photon is absorbed by the rock, and
Speaker 1: where's that energy go It like goes into the bond somehow,
Speaker 1: it makes some rock molecule vibrate more, or if it's
Speaker 1: a gas that you're hitting that it makes those particles
Speaker 1: move faster. It's some sort of internal energy, right, it
Speaker 1: doesn't matter. The mass of that rock goes up when
Speaker 1: it eats that photon, which means like you lie in
Speaker 1: the sun absorbing photons, your mass goes up. Or you know,
Speaker 1: you have an electric car parked in your garage and
Speaker 1: you've plugged it in and now you're adding energy to
Speaker 1: the battery. Its mass is going up, right, because that
Speaker 1: mass is an indicator of how much energy is stored
Speaker 1: inside of whatever kind. As long as it's internal stored energy,
Speaker 1: it contributes to the mass. So the mass is not
Speaker 1: on its own. A new kind of energy it's just
Speaker 1: an d cater of how much energy is stored inside
Speaker 1: and that's what equals MC squared means. E. There doesn't
Speaker 1: mean total energy. It's not saying that all mass is
Speaker 1: energy and all energy is mass. E really means just
Speaker 1: internal stored energy, and there's a fuller equation that captures
Speaker 1: the full energy of the object as a term for
Speaker 1: momentum as well. So it really tells you that energy
Speaker 1: is internal stored energy as revealed by mass and another
Speaker 1: term for energy of motion energy of momentum.
Speaker 3: All right, so mass is just a reflection of kineticum potential.
Speaker 1: Energy, internal stored energy, which could be kinetic or potential. Yes, absolutely.
Speaker 3: Okay, are there other forms of energy or are they
Speaker 3: all essentially just different versions of kinneticum potential energy?
Speaker 1: Period It's a great question and the answer is yes.
Speaker 1: Kineticum potential energy are the two categories of energy, and
Speaker 1: there's nothing else. Right, So everything can be either kinetic
Speaker 1: or potential energy. And if it's internal stored energy, it
Speaker 1: could be kinetic or potential then we call it mass.
Speaker 1: And if it's just motion of the whole object, then
Speaker 1: that's kinetic energy of the whole shebang. And this helps
Speaker 1: you understand things like, well, how can photons have energy
Speaker 1: if they don't have mass. People write to me a
Speaker 1: lot and say, like, photons have energy, right, Well, equals
Speaker 1: empc square, therefore photons have mass, right, Not true, photons
Speaker 1: don't have mass because again that equation equals empc squared.
Speaker 1: That e is just internal stored energy. Photons have no
Speaker 1: internal stored energy because they have no mass. But the
Speaker 1: full equation has a term for momentum in it, and
Speaker 1: photons definitely do have momentum, which is why photons also
Speaker 1: have energy. So you can have energy without having any mass, right,
Speaker 1: because photons again are pure motion energy. And then you
Speaker 1: can play all sorts of fun games to confuse yourself
Speaker 1: by what this means. Like, you know, take a box,
Speaker 1: for example, and shoot a photon in it, and don't
Speaker 1: let the photon get absorbed, put back mirrors inside the box,
Speaker 1: the photon just bounces around. You still just have a
Speaker 1: photon in the box. Then what you've done is you've
Speaker 1: added to the mass of the by adding a massless photon.
Speaker 1: People have this intuition that mass is like the amount
Speaker 1: of stuff in something, but it really isn't. It really
Speaker 1: just captures the internal store energy. Even if you add
Speaker 1: massless things to your box, then you're increasing the mass
Speaker 1: of the box. It's really kind of mind bending. It
Speaker 1: really makes you change your understanding of what mass is.
Speaker 3: I need more coffee, Yeah, but I'm following you. Okay,
Speaker 3: So let's dig in more to this question about you know, when,
Speaker 3: if ever, is energy conserved.
Speaker 2: So you were.
Speaker 3: Talking about throwing a ball in the air and it
Speaker 3: goes from kinetic energy to potential energy, but it doesn't
Speaker 3: always get conserved. Can we talk about the history of
Speaker 3: why we used to think energy was conserved.
Speaker 1: It's a really fascinating story. And you know, for a
Speaker 1: long time we just sort of noticed that energy seemed
Speaker 1: to be conserved. Like if you created a new quantity
Speaker 1: number of ice cream sandwiches or something, and then you
Speaker 1: notice that, weirdly, no matter what you did, the number
Speaker 1: didn't change, Like every time Kelly ate an ice cream sandwich,
Speaker 1: Daniel made one, there was this weird cosmic connection or
Speaker 1: vice versa. Then you'd be like, something is going on here, right,
Speaker 1: Like the universe respects ice cream sandwiches or something.
Speaker 2: I want to live in that use.
Speaker 1: And that's sort of the case for energy. That In
Speaker 1: lots of situations that we studied, energy seems to be conserved,
Speaker 1: and so we assumed that it was same was also
Speaker 1: true for mass. For a long time, people assumed that
Speaker 1: you couldn't create or destroy mass. A lot of people
Speaker 1: still out there repeat that, even though now we know
Speaker 1: that it's not true. We know that you can convert
Speaker 1: mass into energy of motion or into potential energy that's
Speaker 1: not internal. I do that all the time at my
Speaker 1: day job. Right when we smash protons together, we are
Speaker 1: turning their mass into new forms of energy. We're turning
Speaker 1: their energy into mass all the time, back and forth,
Speaker 1: and every time you absorb photons from the Sun, you're
Speaker 1: turning their energy into mass. But that's a hard thing
Speaker 1: to notice unless you have control a tiny part of
Speaker 1: goals and you can see these things happen. Which is
Speaker 1: why chemists for a long time reasonably believed that mass
Speaker 1: was conserved, because they would measure the stuff going into
Speaker 1: a reaction and the stuff coming out of a reaction,
Speaker 1: and they never saw a change to within their measuring uncertainties. Now,
Speaker 1: of course, we know that if they had measured more accurately,
Speaker 1: they would have noticed very tiny changes in mass because
Speaker 1: mass is very very dense stuff. Right. The C square
Speaker 1: there tells you that a big change in energy is
Speaker 1: required to make even a small change in the mass. Anyway,
Speaker 1: the same thing was long true for energy. People are like, okay,
Speaker 1: well mass is not conserved, we're going to give that up.
Speaker 1: But energy still, Energy definitely has got to be a
Speaker 1: conserved right, because people made all these measurements, and it
Speaker 1: seemed like the more accurately you measured it, the more
Speaker 1: you discovered energy had to go somewhere. So in realistic studies,
Speaker 1: for example, say you throw that ball up into the air,
Speaker 1: what's going to happen. Well, it's not going to convert
Speaker 1: all of its kinetic energy into potential because some of
Speaker 1: it's going to get lost to air resistance. Or if
Speaker 1: you roll a ball down a hill, right, some of
Speaker 1: it's going to get lost to friction. That energy seemed
Speaker 1: to creep out of those systems. But as long as
Speaker 1: you define the system to include those things, you account
Speaker 1: for friction and you account for air resistance, you're able
Speaker 1: to account for all of that energy. The balls flying
Speaker 1: up into the air and it loses energy to air resistance,
Speaker 1: but that energy then just goes into heating the air,
Speaker 1: or if you're sliding down a hill and you feel
Speaker 1: friction between your pants and the grass, then you're heating
Speaker 1: up the grass and your pants. That energy is still there.
Speaker 1: And so for a long time people just noticed, even
Speaker 1: with more and more careful accounting, that energy did seem
Speaker 1: to be conserved.
Speaker 3: So I remember that we were talking about Emmy notors on.
Speaker 3: I worked so hard to not say her name during
Speaker 3: the episode because I knew I'd get it wrong, But
Speaker 3: here I went and put myself in that position.
Speaker 2: But anyway, that she had come up with a.
Speaker 3: Really great law or theory that explained when things are
Speaker 3: symmetrical and when they're not. And so it sounds to
Speaker 3: me like we're going to determine here that energy is
Speaker 3: not symmetrical, and that Emmy would tell us that if
Speaker 3: she were here.
Speaker 1: Yeah, it's really cool that we can do more than
Speaker 1: just measure the number of ice cream sandwiches and notice
Speaker 1: that they do or do not change and then conclude something.
Speaker 1: It's not just empirical. We actually now have theoretical ways
Speaker 1: to argue whether something should be conserved or not. And
Speaker 1: as you say, that's due to Emmy Nuther whose name
Speaker 1: I'm sure I'm also mispronouncing, and the number of mispronunciations
Speaker 1: is not conserved. Like it just seems to grow, go
Speaker 1: up and up and up every time I hear this name,
Speaker 1: different pronunciations of it. So German listeners, please don't be
Speaker 1: shy right in and correct our pronunciations. We want to
Speaker 1: get this stuff right anyway. I mean, other told us
Speaker 1: that every time we have a conservation law in the universe.
Speaker 1: You're right, it's connected to some symmetry of the universe.
Speaker 1: And symmetry has a sort of special meaning there. It
Speaker 1: says that you can transform your experiment, you can move
Speaker 1: it or rotate it in some way, and you should
Speaker 1: get the same answer. And so a famous and powerful
Speaker 1: example is momentum conservation. You know, alongside energy, we have
Speaker 1: this concept of moment momentum, which is similar to energy. Right,
Speaker 1: Momentum contributes to your energy. We said, there's internal storat
Speaker 1: energy and then this energy of momentum which come together
Speaker 1: to make your total energy. And the famous and important
Speaker 1: example of that is momentum, which is something that is
Speaker 1: actually conserved in our universe. And when we say symmetry there,
Speaker 1: what we mean is that you can do an experiment
Speaker 1: and then transform the experiment according to some symmetry and
Speaker 1: do the experiment again, you should get the same answer.
Speaker 1: So if you build a physics experiment and you do
Speaker 1: it in space, you know, you collide billiard balls or whatever,
Speaker 1: and then you do it ten meters to the left
Speaker 1: or one hundred meters to the right, or forward one
Speaker 1: thousand meters, you should get the same answer. So that's
Speaker 1: a symmetry of the universe. The universe doesn't care where
Speaker 1: you do your experiment. As long as you set up
Speaker 1: the conditions the same way nearby masses or whatever, you
Speaker 1: should get the same answer. That's a fundamental symmetry of
Speaker 1: the universe. And that symmetry gives you conservation of momentum.
Speaker 1: So Emmy Nuther has this amazing conceptual bridge which you
Speaker 1: tell you what symmetry generates a conservation law. So conservation
Speaker 1: momentum comes from this symmetry of translation, where you don't
Speaker 1: care about where you are in space, where space is relative.
Speaker 1: There's no like official zero, there's no like golden numbers
Speaker 1: glowing in the universe. It doesn't matter where you do
Speaker 1: your experiment. And so now more than just saying hey,
Speaker 1: look I noticed, momentum is conserved. You can say why
Speaker 1: it's conserved, and you can inspect that reason, say does
Speaker 1: that make sense? You know, we can say momentum is
Speaker 1: conserved because the universe has no preferred location. You can
Speaker 1: do your experiment anywhere, and we're like, all right, that
Speaker 1: makes sense and that's a good reason for momentum to
Speaker 1: be conserved. Okay, So what about energy? I mean, not
Speaker 1: there tells us that energy is conserved in the universe
Speaker 1: if the universe's laws don't change with time. Right, So,
Speaker 1: momentum is conserved if the universe's laws don't depend on location,
Speaker 1: if you don't have like different laws of physics in
Speaker 1: different places, Energy is conserved if the laws don't change
Speaker 1: with time. If like this, the same rules of electromagnetism
Speaker 1: applied today and tomorrow and in a thousand years.
Speaker 3: It feels like I want that to be there. But
Speaker 3: I think we've decided that energy is not concerved. Can
Speaker 3: you give me an example of how it's not conserved.
Speaker 1: Yeah, it's fascinating because we assume that the laws of
Speaker 1: physics are constant all the time. Think about just how
Speaker 1: simple it is to read about an experiment in a
Speaker 1: journal and say I'm going to reproduce that experiment and
Speaker 1: see if it's true, and I'm going to do the
Speaker 1: same thing and see if I get the same answer,
Speaker 1: and reproducing it later, and assuming you get the same answer,
Speaker 1: assumes the laws of physics shouldn't change, right, And it's
Speaker 1: really important to our whole process of science that the
Speaker 1: laws of physics were uncovering now are the same as
Speaker 1: they were a thousand years ago or even a billion
Speaker 1: years ago. Like when we look at galaxies deep out
Speaker 1: into space in early times, we assume we know what
Speaker 1: the speed of light was back then, and how mass
Speaker 1: worked and all this kind of stuff. So the universe
Speaker 1: without any constant laws is very difficult the universe to
Speaker 1: do science in, right. And so it's not true that
Speaker 1: the laws of physics are just wially nearly changing with time.
Speaker 1: That's not something we've seen. But there are a couple
Speaker 1: aspects of the laws of physics which do seem to
Speaker 1: be changing with time, and one of them is that
Speaker 1: the universe is expanding, so space itself, the frame in
Speaker 1: which we're doing all of this stuff, is not static.
Speaker 1: And when Emmy Nuther says the universe laws have to
Speaker 1: be constant in time that includes space, right, it means
Speaker 1: space itself needs to be constant the way like conservation
Speaker 1: momentum requires you to be the same location in space,
Speaker 1: it's put in the context of the space in that
Speaker 1: same way, energy conservation requires you to have basically the
Speaker 1: same amount of space. It's not changing the laws of
Speaker 1: electromagnetism or you know, the speed of light or anything.
Speaker 1: It's just saying, hey, the conditions of your experiment are
Speaker 1: not constant because your universe is expanding. And we've known
Speaker 1: for like twenty or so years that the universe is expanding,
Speaker 1: and not just expanding, but accelerating in its expansion, Like
Speaker 1: every year we are making more space between galaxy clusters
Speaker 1: and between ice cream sandwiches and everywhere in the universe.
Speaker 1: Space is expanding. And we actually have a not so
Speaker 1: terrible explanation for why space expanding would mean that energy
Speaker 1: isn't conserved.
Speaker 3: Oh, I want to hear about that after the break.
Speaker 2: All right, we're back.
Speaker 3: So you blew our minds a second ago by explaining
Speaker 3: that the expanding universe is why energy can't be concerned.
Speaker 3: It's crazy to me that something that's happening so far
Speaker 3: away but I guess also happening everywhere is impacting my
Speaker 3: day to day experience of energy.
Speaker 2: But go ahead and tell us the crazy thing you.
Speaker 1: Replaying, William, I think, well, that sounds kind of abstract, right,
Speaker 1: Like you're telling me the universe is expanding, and so
Speaker 1: in some sense the context of our experiments is changing.
Speaker 1: But why does that mean that energy is not conserved?
Speaker 1: Like is energy being created somewhere or destroyed somewhere. So
Speaker 1: let's tack into the details there, Like energy actually is
Speaker 1: being created by the expansion of the universe. We talk
Speaker 1: about the expansion of space as creating more space, right,
Speaker 1: Like the distance between us and some cluster galaxy is growing,
Speaker 1: and not because we're applying some force to accelerate away
Speaker 1: from them. This is just like general relativity. Space is expanding, right,
Speaker 1: We're not measuring any acceleration. They're not measuring any acceleration
Speaker 1: with their accelerometers. But the distance between our galaxies is
Speaker 1: increasing and faster and faster every year. So new space
Speaker 1: is being made. Well, what does that mean? For new
Speaker 1: space to be made? Space is filled with quantum fields, right,
Speaker 1: There's the electron field, there's electromagnetic field, there's fields for
Speaker 1: all the quarks, all these fields in space, and all
Speaker 1: those fields have non zero energy, like these are quantum fields,
Speaker 1: which means they can never go down to total zero.
Speaker 1: They always have some energy in them. So you pop
Speaker 1: a new cube of space, boom, it comes with quantum
Speaker 1: fields that have energy in them. Right, So new space
Speaker 1: means new energy. So right there, making more space means
Speaker 1: you're creating energy, that doesn't It just.
Speaker 3: Mean the energy gets spread more thin across this new space.
Speaker 1: Because every chunk of space is the same and the
Speaker 1: rules of quantum mechanics have a minimum requirement of that energy.
Speaker 1: It's not something we deeply understand, but it's something that's
Speaker 1: required for the accelerated expansion of the universe. We know
Speaker 1: that dark energy behaves this way. We see, for example,
Speaker 1: as the universe expands, the density of dark energy doesn't
Speaker 1: change in the universe like the density of protons goes down.
Speaker 1: You have a certain number of protons, you know, some
Speaker 1: huge number of protons in the universe. As the volume
Speaker 1: of the universe increases, the density of those protons drops
Speaker 1: exactly the way you would expect. Right you double the volume,
Speaker 1: that density goes down by a factor too. But dark energies.
Speaker 1: Density does not decrease. You double the volume, the density
Speaker 1: stays the same. Right, So dark energy behaves in this
Speaker 1: weird way that when you create more space, you also
Speaker 1: create more dark energy.
Speaker 2: Where does it come from?
Speaker 1: Where does it come from? Yeah?
Speaker 2: How does that keep happening?
Speaker 1: You ask where it comes from? And that's a question
Speaker 1: that only makes sense if it's conserved, if it has
Speaker 1: to come from somewhere, right, Like if I make an
Speaker 1: ice cream sandwich, do you say, hey, where did that
Speaker 1: ice cream sandwich come from? That seems to violate the
Speaker 1: loss of physics.
Speaker 3: You're like, no, I wouldn't ask questions about a new
Speaker 3: ice cream sandwich, Dane, I would just enjoy it.
Speaker 1: Right, go on. You know it's true you have to
Speaker 1: assemble it out of bits, But like the assembly itself
Speaker 1: didn't violate some law physics. You didn't have to destroy
Speaker 1: an ice cream sandwich somewhere else to make this one. Right,
Speaker 1: there's no limit on the number of ice cream sandwiches.
Speaker 2: Thank the Lord, hallelujah.
Speaker 1: Yeah, I know, we're all relieved. And so that question
Speaker 1: where does the energy come from? Only make sense if
Speaker 1: things have to flow. If you can just change the
Speaker 1: total energy in the universe or change under ice cream sandwiches.
Speaker 1: Then the question itself isn't actually as meaningful.
Speaker 3: Right, So energy comes from nowhere. Energy can just like poop,
Speaker 3: pop up.
Speaker 1: Energy can just pop up. Yeah, absolutely, and you can
Speaker 1: also disappear.
Speaker 6: Right.
Speaker 1: We talked about how the density of protons changes as
Speaker 1: the universe expands and the density of dark energy. So
Speaker 1: protons dilute in a way that makes a lot of sense, right,
Speaker 1: Like you double the volume, the density goes down by
Speaker 1: a factor of two. Interestingly, side note, same thing is
Speaker 1: true of dark matter dark matter. As you double the
Speaker 1: volume of the universe, dark matter density drops by two,
Speaker 1: which is one reason why we think of dark matter
Speaker 1: as matter, because it dilutes the way it matter does,
Speaker 1: because radiation doesn't photons, As you double the volume of
Speaker 1: the universe, their energy density drops by more than two.
Speaker 1: Like you have a certain number of photons in the universe.
Speaker 1: Now you increase the volume of the universe, you have
Speaker 1: the same number of photons and more volumes. You might think, oh,
Speaker 1: the energy density just decreases because you've increase the volume.
Speaker 1: Not true, because the expansion of space also red shifts
Speaker 1: those photons. It stretches their wavelength to rhetoric or longer wavelengths.
Speaker 1: Longer wavelength means lower energy. So you have a universe
Speaker 1: filled with photons, you expand that universe, their energy density
Speaker 1: drops faster than the energy density of matter or dark matter.
Speaker 1: Where does that energy go? It doesn't have to go anywhere.
Speaker 3: It just goes moves into the space that was just created.
Speaker 2: I've solved it. Where's my Nobel price?
Speaker 1: I love that idea. People are right to be about
Speaker 1: that a lot. They're like, Okay, energy is creative when
Speaker 1: you expand space and also destroyed. Do these two numbers
Speaker 1: add up, And it would be amazing if they did, right,
Speaker 1: And that would be a beautiful explanation, you know, plus
Speaker 1: seven thousand minus seven thousand boom. I think we figured
Speaker 1: it out. These two numbers are vastly different scales. Like
Speaker 1: the energy and photons in the universe is tiny, like
Speaker 1: much less than one percent of all the energy and
Speaker 1: universe is in photons, but the dark energy of the
Speaker 1: universe is like two thirds of all the energy. So
Speaker 1: energy is increasing in dark energy much much more rapidly
Speaker 1: than energy is decreasing by redshift of photons. So we
Speaker 1: don't think that photons are like getting turned into dark
Speaker 1: energy or anything.
Speaker 3: Okay, So bottom line here, we don't know where energy
Speaker 3: comes from. We know it's not conserved. Physicists have job security.
Speaker 1: Yeah, we don't even really still have an answer to
Speaker 1: the original question of like what is energy? Right, still
Speaker 1: a description of something we've seen, and we have a
Speaker 1: little bit more theoretical footing now because we could, in
Speaker 1: principle define energy as the thing that would be conserved
Speaker 1: if the laws of physics were perfectly symmetric in time. Right,
Speaker 1: you can use Nuther's theorem as a definition of energy
Speaker 1: and say, oh, energy is that thing which would be conserved.
Speaker 1: And that's kind of cool. I like that. It is
Speaker 1: very theoretically grounded, but it doesn't give you like a
Speaker 1: conceptual sense for like what is this thing? But unfortunately
Speaker 1: that sort of turns you back to the philosophy of it, like, well,
Speaker 1: what do you mean what is this thing? What kind
Speaker 1: of answer are you looking for when you ask what
Speaker 1: is energy? Part of the question is not satisfied by like, well,
Speaker 1: here's the description of the kinds of energy, here are
Speaker 1: the rules that it follows. Here's how it's created, here's
Speaker 1: how it's destroyed. Here's how it's not concerned. But part
Speaker 1: of the question is not answered by that description.
Speaker 2: Do you think I have no idea?
Speaker 1: Yeah, I feel like there's something about it that's still unsatisfied,
Speaker 1: that's still like yeah, but what is it? You know, like,
Speaker 1: why do we have it? Where does it come from?
Speaker 1: It's a deep human question, but like the human questions
Speaker 1: we ask, aren't always the appropriate questions, aren't always the
Speaker 1: ones that answer the question. Sometimes we discover that something
Speaker 1: is different from how we expected it to behave and
Speaker 1: that means the kind of questions we should ask about
Speaker 1: it are changing. Because energy isn't something that comes from somewhere.
Speaker 1: It's a feature of the universe, and it does seem
Speaker 1: to be important because under lots of context it is conserved,
Speaker 1: but it's not fundamental in that way, and so it
Speaker 1: could just be something that humans notice, something the humans
Speaker 1: like to calculate, something that connects with our everyday experience
Speaker 1: in a way that it's important to us, but isn't
Speaker 1: Like alien physicists, for example.
Speaker 3: It only appears to be conserved on human scales because
Speaker 3: it's being lost at such low numbers it's hard to measure,
Speaker 3: but it's not even conserved on small scales.
Speaker 2: It just looks that way.
Speaker 1: Yeah, that's exactly right. And I think it's useful to
Speaker 1: think about this because it impacts other questions we have.
Speaker 1: Like a lot of listeners who wrote in Thought about
Speaker 1: the conservation of energy, and it talked about how the
Speaker 1: Big Bang had energy, and maybe all the energy in
Speaker 1: the universe just came from the Big Bang, right, And
Speaker 1: so I hope the answer today reveals that, like, no,
Speaker 1: there's some energy in the universe which was created after
Speaker 1: the Big Bang. Right, This expansion of the universe is
Speaker 1: making energy, and that's post Big Bang energy. And also
Speaker 1: some of the energy of the Big Bang is gone now.
Speaker 1: Like you have the Big Bang, you have matter and
Speaker 1: anti matter created, they annihilate. You have a universe mostly
Speaker 1: filled briefly with photons. So photons did dominate the universe
Speaker 1: energy budget initially, but a lot of those photons are
Speaker 1: now red shifted and their energy is gone. Like we
Speaker 1: talk on the podcast a lot about the cosmic microwave
Speaker 1: background radiation, this energy from the early universe that reveals
Speaker 1: so much about how the universe came together and what
Speaker 1: it means and how it rippled. But those photons are
Speaker 1: very very red. They're at a temperature of like two
Speaker 1: point seven calvin, very very cold. The plasma that made
Speaker 1: them was like three hundred thousand degrees calvin. Right, they
Speaker 1: were a glow of them, a very very hot plasma,
Speaker 1: very energetic photons. Originally that energy is just gone now right,
Speaker 1: It didn't go anywhere. So a lot of the energy
Speaker 1: in the universe didn't come from the Big Bang, and
Speaker 1: a lot of the energy of the Big Bang is
Speaker 1: now gone, it's fizzled out.
Speaker 3: Do we have less energy over time, more energy over time,
Speaker 3: or do we not know how this balance is working out.
Speaker 1: We definitely have more energy over time because dark energy
Speaker 1: is much more dramatic, and so all the energy created
Speaker 1: by dark energy, the expansion of the universe vastly outweighs
Speaker 1: the energy loss due to red shifts of photons.
Speaker 2: You would said that earlier.
Speaker 3: But is that the only way that energy is lost
Speaker 3: or is energy lost while humans are doing all of
Speaker 3: these reactions down here, and is that impacting the like
Speaker 3: mass balance equation.
Speaker 2: For the universe?
Speaker 1: To my knowledge, the expansion of the universe is the
Speaker 1: only source of energy gain or loss. Right, You noticed
Speaker 1: that it's an underlying mechanism for both of these things,
Speaker 1: because it's the place that Norther's theorem is violated, right,
Speaker 1: It's the thing that doesn't respect the time symmetry. So
Speaker 1: the expansion of the universe redshifts those photons, breaking conservation
Speaker 1: of energy and creates news space breaking conservation of energy.
Speaker 1: So anything that's sensitive to the expansion of the universe
Speaker 1: can be a source of the violation of conservation of energy.
Speaker 1: And I want to make another comment about the Big Bang,
Speaker 1: which is it seems like a little bit of a
Speaker 1: loss of power to explain and explore, Like if energy
Speaker 1: was conserved, then we could do this cool thing of
Speaker 1: tracing it back into the Sun and then where that
Speaker 1: came from, where that came from, all the way back
Speaker 1: to the Big Bang. It's like we have a ledger,
Speaker 1: you know, the tell us how energy slashes around, and
Speaker 1: maybe by tracing that we could learn something. And that
Speaker 1: seems really cool, and it feels like, oh, oh, maybe
Speaker 1: we've lost that. Maybe we can no longer learn about
Speaker 1: the Big Bang by studying energy. Well, just now we
Speaker 1: can ask different questions, you know, we can ask how
Speaker 1: the energy for the Big Bang came about, Like we
Speaker 1: know that the universe was filled with hot, frothing energy
Speaker 1: early on. Where did that come from? We no longer
Speaker 1: have to just answer that by saying, oh, it came
Speaker 1: from this other thing with equal energy. Now we have
Speaker 1: more ideas about how you can create all that energy
Speaker 1: from some earlier denser states. So, if anything, it opens
Speaker 1: up the examination to think differently about the origin of
Speaker 1: the universe. And you know, that's what we want. We
Speaker 1: want our understanding of physics to evolve and to give
Speaker 1: us new ways to think about the whole context of
Speaker 1: reality and where it all came from. And so to me,
Speaker 1: that's exciting. It like removes blinders a little bit and
Speaker 1: gives us a broader sense for how the universe works
Speaker 1: and maybe how it all started.
Speaker 3: I bet you are great at writing grants. Okay, we
Speaker 3: were wrong about that, but that's okay, because it's the
Speaker 3: fascinating thing is actually revealed now.
Speaker 1: So please send me a million dollars to make a
Speaker 1: lot of ice cream sandwiches, because I have a lot
Speaker 1: to learn.
Speaker 3: You know, please share those ice cream sandwiches. Daniel, Yes,
Speaker 3: Daniel needs this money.
Speaker 1: It's important, everybody exactly. My cookies and cream project really
Speaker 1: top priority for national security.
Speaker 2: That's right, that's right, all right.
Speaker 3: Well, I learned a ton today actually, and I can't
Speaker 3: wait to tell my daughter actually about some of this
Speaker 3: stuff and blow her mind somehow.
Speaker 2: I feel like she's going to find this really interesting.
Speaker 1: Yeah. So energy is not conserved, which means it doesn't
Speaker 1: have to con from anywhere. But our understanding does seem
Speaker 1: to be growing, and it seems to em and a
Speaker 1: from these deep studies of how the universe works. So
Speaker 1: let's keep doing that.
Speaker 3: Let's hope our understanding is expanding faster than the information
Speaker 3: we're losing.
Speaker 1: All right, go off and enjoy ice cream sandwich. Everyone
Speaker 1: on us?
Speaker 2: Oh, not on us, Not on us, Daniel.
Speaker 1: Virtually on us, spiritually on us.
Speaker 2: Don't send us three sets.
Speaker 1: That's all right, emotionally on us.
Speaker 2: There you go, Okay.
Speaker 3: Daniel and Kelly's Extraordinary Universe is produced by iHeartRadio.
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Speaker 1: Extraordinary Universe.
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