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Speaker 1: One of my favorite things about physics is that it

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Speaker 1: lets us think concretely and carefully about the basic nature

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Speaker 1: of our experience. What is space? What is matter? What

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Speaker 1: is time? What's a particle? Why are there waves everywhere?

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Speaker 1: Physics helps us convert these squishy conversations on rooftops over

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Speaker 1: smoke banana peels into robust mathematics. The math doesn't require

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Speaker 1: persuasion or a clever choice of words. It's either right

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Speaker 1: or it's wrong. So instead of answering a question about

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Speaker 1: the nature of the squish universe, we get to poke

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Speaker 1: and prod our mathematical description of it. Sometimes that gives

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Speaker 1: us real insight, like when relativity tells us that distance

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Speaker 1: and velocity have to be relative rather than absolute, because

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Speaker 1: that's the only mathematical model that describes the universe we see.

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Speaker 1: Other times it surprises us by telling us that we

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Speaker 1: might just be asking the wrong question. Maybe the things

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Speaker 1: we thought were important just reveal our fundamental misunderstandings of

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Speaker 1: the universe and how it works. Today we'll be asking

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Speaker 1: what physics can tell us about energy, What is it?

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Speaker 1: And more importantly, where does it come from? Welcome to

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Speaker 1: Daniel and Kelly's Extraordinary energetic Universe.

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Speaker 2: Hello. I'm Kelly Wiener Smith.

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Speaker 3: I study space and parasites and I just got over

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Speaker 3: having the flu for a week and I really could

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Speaker 3: have used energy.

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Speaker 1: Hi. I'm Daniel. I'm a particle physicist and I love

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Speaker 1: how Kelly opens the podcast with so much energy every time.

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Speaker 2: Okay, well we both have a lot of energy.

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Speaker 3: Speaking of energy, do you rely on caffeine? What is

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Speaker 3: your favorite form of liquid energy?

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Speaker 1: I do rely on caffeine. I'm drinking coffee right now here.

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Speaker 1: You go, Oh oh for you asmr. Folks. Yeah, yes,

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Speaker 1: I have caffeine in the mornings, but I can't have

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Speaker 1: any really after lunch or interference with my sleep. I'm

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Speaker 1: at that age where sleep is not necessarily a given.

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Speaker 2: Yeah. Same.

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Speaker 3: I used to drink coffee all day long. I like

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Speaker 3: didn't drink water in college.

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Speaker 1: That doesn't sound like a good idea.

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Speaker 3: You know, I got a lot done, I got a

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Speaker 3: whole lot done, but I could still fall asleep. But

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Speaker 3: now I also if it's after lunch, forget it. I

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Speaker 3: can't have coffee anymore either.

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Speaker 1: Remember, folks, this is not a health podcast. Do not

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Speaker 1: take our advice.

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Speaker 3: Noah, no, please don't don't follow our lead. When you

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Speaker 3: were a kid, did you ever try jolts?

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Speaker 1: Jolt was the kind of thing that was so forbidden

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Speaker 1: in my family. Like my mom was very controlling about

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Speaker 1: the kind of food we could eat, you know, she

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Speaker 1: like counted potato chips, this kind of thing, So junk

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Speaker 1: food definitely off of this jolt. She saw that as

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Speaker 1: like battery acid, Like there was no way she would

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Speaker 1: allow us. Did you try jolts?

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Speaker 2: Yeah? Do you remember pixie stick?

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Speaker 1: Yeah?

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Speaker 3: So there used to be like a megapixie stick. It

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Speaker 3: was like a giant plastic tube like the thickness of

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Speaker 3: my thumb, and it was just filled with.

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Speaker 2: Sugar and food coloring.

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Speaker 3: And we had like a party once where we just

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Speaker 3: like had those pixie sticks with jolts.

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Speaker 2: And I got pretty sick.

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Speaker 3: And jolts made me feel horrible the way too much

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Speaker 3: caffeine makes me feel now.

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Speaker 2: But I tried it once, and it was one thing

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Speaker 2: as a kid.

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Speaker 3: Where I was like, I shouldn't do that again. Anyway,

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Speaker 3: I had a lot more fun.

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Speaker 1: It sounds like it does sound like you had more fun,

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Speaker 1: but you also got sick. But I have a basic

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Speaker 1: biology question for you about caffeine. I mean, I understand

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Speaker 1: if you eat a pixie stick, it's sugar. Sugar has energy.

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Speaker 1: You could potentially get high and a rush and feel

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Speaker 1: energetic from that. But caffeine, how does that give me

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Speaker 1: energy or make me alert? Is it really energy from

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Speaker 1: the caffeine that my body's using. Is it releasing some

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Speaker 1: energy stores in my body? Or is it some much

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Speaker 1: more complicated neuro answer, dot dot dot. It depends.

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Speaker 2: Probably, it depends. I don't actually know.

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Speaker 3: I didn't prepare the answer for that coming in here.

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Speaker 3: I believe it binds to certain receptors in your brain.

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Speaker 3: My job in college was barista. I worked at like

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Speaker 3: four different coffee shops, and so I've had like shirts

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Speaker 3: with the caffeine molecule on the front. So yeah, I

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Speaker 3: think it binds with some receptors in your brain. And

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Speaker 3: I don't know how that results in you feeling awake,

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Speaker 3: but it works.

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Speaker 1: It pulls on some levers and ropes of the Rube

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Speaker 1: Goldberg machine that is my mind.

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Speaker 3: That's right, that's right, and thank God for it. I

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Speaker 3: don't know how I would have gotten through college without it.

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Speaker 3: At some point I was working at a coffee shop

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Speaker 3: because I couldn't afford all the coffee I wanted to drink,

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Speaker 3: but if I worked at the coffee shop, I could

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Speaker 3: afford it and pay my rent. So anyway, I had

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Speaker 3: a problem maybe, but I also had fun.

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Speaker 1: Well. Energy is a really fun topic because it's something

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Speaker 1: that is colloquial and we talk about it in our

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Speaker 1: lives and whether you feel energetic and whether you drink

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Speaker 1: caffeine whatever, And it's also something deeply important to physics

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Speaker 1: and the universe. So it's one of these topics that

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Speaker 1: people have like a personal feeling about, like where energy is,

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Speaker 1: where it comes from, and what it means. And it's

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Speaker 1: also really pervasive in popular science. You know, equals MC squared,

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Speaker 1: energy is mass. People tell us there's a lot of

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Speaker 1: nonsense out there about energy. So I thought it'd be

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Speaker 1: good to have an episode where we dig into some

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Speaker 1: details about what energy is and where it comes from

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Speaker 1: and what we know and don't know about it.

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Speaker 3: Yes, and you always do a great job of getting

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Speaker 3: us back on tracks. That was fantastic, and the other

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Speaker 3: people who keep us on track are our amazing audience,

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Speaker 3: and so we asked them where does energy come from?

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Speaker 3: And if you want to answer questions for us, you

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Speaker 3: can write us at questions at Daniel and Kelly dot org.

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Speaker 3: But let's go ahead and here from our audience, where

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Speaker 3: does energy come from?

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Speaker 1: Energy comes from heat, which comes from photon. I have

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Speaker 1: no idea.

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Speaker 4: Is it a mathematical trick, is it just an accounting system?

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Speaker 1: Who else? Nobody knows where energy comes from, and nobody's

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Speaker 1: ever gonna know. It is the magic of the universe.

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Speaker 5: I don't think energy comes from anyway, because you can't

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Speaker 5: have not energy.

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Speaker 1: Well, it comes from fields that permeate the entire universe.

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Speaker 1: Energy comes from hydrogen fusion caused by gravity, So I'd

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Speaker 1: have to say gravity.

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Speaker 4: Yes, it comes from the Big Bang and has just

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Speaker 4: been circulating in different forms ever since. Or powered Now,

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Speaker 4: if you're talking about the energy that powered the Big Bang,

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Speaker 4: or energy required to keep all the quantum fuels fluctuating

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Speaker 4: and alive, I imagine a physicist is better suited to

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Speaker 4: provide insight.

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Speaker 1: Hint, hint, So I guess that MLGS comes from symmetries

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Speaker 1: in nature. Obviously the Big Bang has a big role

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Speaker 1: in it, but it might not be the whole thought.

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Speaker 6: Since you can't create energy, I assume it originates from

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Speaker 6: the Big Bang, and before then who knows.

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Speaker 1: I guess it's always better around.

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Speaker 6: It just changes form after form.

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Speaker 1: Perhaps what we're calling space time is actually energy. Oh well,

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Speaker 1: I really am stumped by this one. I really don't know.

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Speaker 1: All the energy in the universe today came from the

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Speaker 1: storehouse of energy released in the Big Bang.

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Speaker 5: Some energy comes from the Big Bang, and some comes

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Speaker 5: from dark energy, but most energy in this universe comes

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Speaker 5: from eating your waities.

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Speaker 6: Have we not always had the same amount of energy?

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Speaker 5: I would say all energy originated from the Big Bang

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Speaker 5: and everything since then it's just been conversions of different forms.

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Speaker 5: But then you can ask where did that come from?

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Speaker 5: And where does dark energy come from?

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Speaker 1: And I don't know. There's some really philosophical answers in here,

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Speaker 1: and I loved listening to these.

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Speaker 2: Well, I mean, that's what I've come to expect from

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Speaker 2: the audience.

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Speaker 3: It's like always a nice combination of like philosophical some

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Speaker 3: people who get like exactly the right answer or get

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Speaker 3: really close, and then some people who know they don't

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Speaker 3: know and so they.

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Speaker 2: Just go all in on being hilarious.

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Speaker 3: I always love listening to the answers.

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Speaker 1: This comment that you can't have not energy, I had

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Speaker 1: to pause that and think about it for a while.

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Speaker 1: I was like, Wow, that sounds really profound, but I'm

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Speaker 1: not even share what it means.

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Speaker 3: Like a lot of philosophy, I thought that they were

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Speaker 3: trying to say, if there wasn't energy, none of us

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Speaker 3: would be here, which doesn't really the answer the question

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Speaker 3: where it comes from, but just something had to have

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Speaker 3: made it exist.

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Speaker 2: I don't know, what do you think?

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Speaker 1: I didn't know? Yeah, what is not energy? Is that

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Speaker 1: energy equals zero. It's true, you can't have zero energy

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Speaker 1: in the universe because of quantum mechanics. Yeah, fascinating, Yeah,

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Speaker 1: really fun answers here and a lot of assumptions. You

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Speaker 1: hear that energy doesn't come from anywhere because we've had

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Speaker 1: the same amount the whole time. Because people have this

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Speaker 1: conception which we're going to take apart and debunk a

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Speaker 1: little bit, that energy is conserved. The energy has to

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Speaker 1: come from somewhere because you can either create nor destroy it,

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Speaker 1: and therefore it can only flow.

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Speaker 3: So yeah, when I was looking through your outline and

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Speaker 3: I saw energy is not conserved, I was like, what,

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Speaker 3: I'm sure I've heard that a lot of times, and so,

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Speaker 3: you know, I think a lot of us are looking

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Speaker 3: forward to having our preconceptions about energy sort of cleared up.

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Speaker 1: Yeah, exactly. But before we get into the mind blowing

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Speaker 1: revelations about the nature of energy, we have to be

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Speaker 1: clear and careful about what is it we're talking about anyway.

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Speaker 1: Are we talking about how the earth keeps warm? Are

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Speaker 1: we talking about what happens when you eat your wheaties?

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Speaker 1: Are we talking about philosophical revelations about the fundamental nature

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Speaker 1: of the universe. So the first thing we have to do,

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Speaker 1: of course, is define what do we mean when we

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Speaker 1: say energy.

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Speaker 3: Yeah, so as a biologist, I'm thinking ATP, I'm thinking

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Speaker 3: at it at a chemistry level. We're as a physicist.

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Speaker 3: Do you think about it like that as well? Or

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Speaker 3: this is just a totally different topic.

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Speaker 1: Now ATP is like a chemical store of energy, so

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Speaker 1: it's completely related to the topic at hand. But it's

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Speaker 1: an example, right. It's like if somebody says to you, hey,

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Speaker 1: what is a vegetable and you're like, an implant is

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Speaker 1: a vegetable, And you're like, yeah, that's true, but what

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Speaker 1: makes it vegetable? Why do we have them? Where do

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Speaker 1: vegetables come from? Right? Showing you an a plant doesn't

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Speaker 1: answer that question.

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Speaker 3: Right, and then I'll go on a long rant about

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Speaker 3: how vegetables not a phylogenetic category and it's something humans

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Speaker 3: made up, and so anyway, go ahead.

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Speaker 1: Oh my gosh, wow, oh I love when we accidentally

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Speaker 1: stumble up upon a hidden Kelly rant. Love that. Wow.

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Speaker 3: Okay, let's go deeper, hurt, but not on vegetables. So

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Speaker 3: what is energy? How does a physicist start to answer

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Speaker 3: this question?

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Speaker 1: I like to answer this question by pointing out that

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Speaker 1: we can invent any kind of concept. I mean, you

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Speaker 1: can just make up a word called it, you know,

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Speaker 1: bliblyon or whatever, and then define it and it could

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Speaker 1: be a thing. And the question is like, does that

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Speaker 1: reveal anything about the universe? Is it related to the

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Speaker 1: physical universe in some insightful way, or is it just

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Speaker 1: some nonsense that you made up? And so, from that

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Speaker 1: point of view, like everything in physics is something we

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Speaker 1: made up, and a lot of it is just nonsense

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Speaker 1: we then ignore because it wasn't useful. And some of

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Speaker 1: it actually seems to reflect something that's happening in the

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Speaker 1: universe and is therefore useful, and we think maybe in

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Speaker 1: delightful about the fundamental nature of reality. Right, And so

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Speaker 1: energy is that way. It is something we invented. It's

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Speaker 1: just like a concept we came up with. We talked

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Speaker 1: recently on the podcast about entropy and the history of

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Speaker 1: energy is similar predates entropy because entropy was defined as

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Speaker 1: moving of energy the een and entropy comes from energy.

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Speaker 1: But this is something people have been wondering about it

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Speaker 1: for a long time, like how do you get a

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Speaker 1: machine to work? And what's going on with heat a temperature?

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Speaker 1: And so people came up with this concept of energy

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Speaker 1: one hundreds of years ago. It was actually leading It's

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Speaker 1: first identified energy of motion, like things in motion have energy,

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Speaker 1: and he called it this visviva, this living force, just

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Speaker 1: energy of motion. He recognized that.

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Speaker 3: That was like a thing, but like an asteroid hurtling

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Speaker 3: towards the Earth would have energy. But in what way

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Speaker 3: is that a living force? Was he like specifically thinking

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Speaker 3: about living organism.

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Speaker 1: No, he was just thinking about animation, not necessarily like

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Speaker 1: something is alive, but in motion. And so I think

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Speaker 1: he was thinking more about the motion than the actual

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Speaker 1: life force or the definition of life in some sort

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Speaker 1: of biological way. But that's something we still recognize, right.

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Speaker 1: We call that kinetic energy today and kinetic energy is

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Speaker 1: definitely a form of energy, like photons have energy, right,

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Speaker 1: they zoom around the universe. They're moving really really fast,

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Speaker 1: So it's a type of energy. But again, this is

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Speaker 1: like quoting the eggplant, right, it's not a definition of

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Speaker 1: the concept. It's an example of the kind of thing,

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Speaker 1: and it comes from history. And something that's especially fascinating

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Speaker 1: and revealing about kinetic energy is that it's not conserved. Right.

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Speaker 1: For example, you throw a ball up into the air,

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Speaker 1: it slows down, right because of gravity. If you throw

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Speaker 1: it straight up, it slows down, and eventually, when it

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Speaker 1: reaches the top of its arc, its stopped. So kinetic

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Speaker 1: energy on its own is not something that's conserved in

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Speaker 1: the universe, Like the universe doesn't seem to have a

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Speaker 1: special relationship with kinetic energy. It's the way you could

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Speaker 1: make up any other thing, like, hey, how many ice

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Speaker 1: cream cones are there currently in the universe. That's a

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Speaker 1: number that we don't expect to stay constant. Right, I

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Speaker 1: eat one, it's gone. I've decreased the number. I make one,

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Speaker 1: it goes up. Kelly makes five thousand ice cream cones,

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Speaker 1: it goes up a lot. Right, It's not anything meaningful

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Speaker 1: or specific and kinetic energy is sort of the same way.

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Speaker 1: Like when the ball gets thrown up into the air,

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Speaker 1: it loses that kinetic energy. Where does the kinetic energy go. Well,

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Speaker 1: energy can just go up and down. In this case,

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Speaker 1: we know it actually transforms into another kind of energy

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Speaker 1: we call potential energy, because now that ball has gained altitude,

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Speaker 1: which means it's moved up in the gravitational field, and

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Speaker 1: so it's imbued now with something we call potential energy.

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Speaker 1: And so now we have two kinds of energy kinetic energy,

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Speaker 1: energy of motion, and potential energy, which is energy of

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Speaker 1: position or arrangement.

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Speaker 3: Okay, do all different kinds of energy have the same units?

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Speaker 1: Yes?

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Speaker 2: Units, help me think about scientific phenomena.

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Speaker 1: Yes, all energy has the same unit. So you can

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Speaker 1: use jewels, for example, as a unit of energy, and

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Speaker 1: kinetic energy can be calculated in jewels, and potential energy

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Speaker 1: also calculated in jewels, and you can go back and forth. Right,

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Speaker 1: if you're standing on the top of a building, you

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Speaker 1: have a lot of potential energy because you're high up,

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Speaker 1: you have a lot of altitude, and you jump off

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Speaker 1: that building. You turn that potential energy into kinetic energy

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Speaker 1: because by the time you get to the bottom of

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Speaker 1: the building. You no longer have the altitude, so you

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Speaker 1: have no potential energy, and you have a lot of velocity. Right,

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Speaker 1: So you've turned potential energy into kinetic energy. And you

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Speaker 1: roll a ball up a hill, or you throw a

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Speaker 1: ball up in the air, kinetic energy turns into potential energy.

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Speaker 1: And the same thing is true for example, like a spring.

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Speaker 1: A spring is a way to store potential energy. And

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Speaker 1: if you push on a spring and then you let

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Speaker 1: it go, it will oscillate back and forth and back

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Speaker 1: and forth. And what's happening there is it's slashing kinetic

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Speaker 1: energy into potential energy, back into kinetic energy, back into

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Speaker 1: potential energy. So you know, like a simple model of

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Speaker 1: you have a block of stone on a spring, it'll

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Speaker 1: just sit there oscillating back and forth if there's no friction,

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Speaker 1: turning kinetic and potential energy back and forth into each other.

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Speaker 1: Which is also a really helpful way of thinking about

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Speaker 1: waves in general. Like whenever we're talking about fields oscillating,

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Speaker 1: even quantum fields, that's what's happening is that they're sloshing

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Speaker 1: back and forth between different kinds of energy. And so

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Speaker 1: now we go from having just kinetic energy energy of

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Speaker 1: motion to having two kinds of energy, which, if there's

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Speaker 1: no friction, do appear to conserve the total energy. So

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Speaker 1: kinetic energy not conserved, potential energy not conserved, but their

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Speaker 1: combination in simple systems with no friction or irresistance or

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Speaker 1: anything does seem to be conserved, which suggests that it's

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Speaker 1: like something may be more important to the universe.

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Speaker 3: Okay, all right, So for the examples that we've talked

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Speaker 3: about so far, you've got like a ball rolling down

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Speaker 3: a hill, or a ball being thrown up in the

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Speaker 3: air or something that it seems like the energy for

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Speaker 3: those activities came from the energy of the person who's

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Speaker 3: making it happen. Is that an okay way to think

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Speaker 3: about it? Both of those examples seem the energy is

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Speaker 3: coming from the person who set the ball in motion.

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Speaker 1: Or carried it originally to the top of the building

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Speaker 1: and dropped it.

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Speaker 3: Yeah, right, right, Okay, so we haven't really gotten to

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Speaker 3: where energy came from because energy seems like it's coming

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Speaker 3: from the person who started it.

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Speaker 2: Is that a fair way to think about it?

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Speaker 1: Yeah? I think that's fair. And there's something cool you

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Speaker 1: can do there, which is sort of trace the path

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Speaker 1: of the energy. Right, Like say the person threw the

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Speaker 1: ball into the air, So you're right, it has potential

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Speaker 1: energy which came from its kinetic energy, which came from

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Speaker 1: the energy stored in that person's muscles, right, which converted

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Speaker 1: some sort of chemical energy storage into the contraction of

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Speaker 1: those muscle cells, which accelerated the ball. And that chemical

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Speaker 1: energy storage came from something that person ate, right. And

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Speaker 1: that thing the person ate probably grew and maybe it

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Speaker 1: was an animal and ate plants, or maybe it was

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Speaker 1: a plant directly and that grew somehow by drinking light

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Speaker 1: from the sun. Right. And so you can play this

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Speaker 1: game where you trace the energy back, and one of

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Speaker 1: our listeners commented that a lot of the energy on

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Speaker 1: Earth seems to come from the sun, which is true, right,

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Speaker 1: There's like a little bit of a source of energy

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Speaker 1: from inside the Earth, but most of the energy does

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Speaker 1: come from the Sun. And playing this game tracing the

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Speaker 1: energy back has inside of it an implicit assumption that

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Speaker 1: you can trace energy because again, it has to come

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Speaker 1: from somewhere because it's conserved. It doesn't just disappear and

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Speaker 1: it doesn't appear. And again I'm not saying that energy

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Speaker 1: is conserved. I'm saying that if energy were conserved, then

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Speaker 1: you can play this game, which is really fascinating because

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Speaker 1: it allows you to like, you know, sort of rewind

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Speaker 1: the accounting of the universe, and it is kind of

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Speaker 1: mind blowing to realize that, like, wow, almost all the

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Speaker 1: energy that we use here on Earth was originally created

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Speaker 1: in the sun by fusion and then gobbled up by plants.

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Speaker 3: All right, let's take a break, and when we come back,

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Speaker 3: we are going to dig into whether or not mass

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Speaker 3: could be considered a kind of energy.

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Speaker 2: All right, we're back.

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Speaker 3: So before the break, we were talking about how a

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Speaker 3: lot of energy on Earth comes from the Sun, and

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Speaker 3: so I'm thinking about you know, plants growing, putting on

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Speaker 3: mass as you know, their chloroplasts, or turning energy from

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Speaker 3: the Sun into energy for them, and then I eat

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Speaker 3: them and put on a little bit of mass, just

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Speaker 3: a little and use that energy to make a lot

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Speaker 3: of ice cream cones, which makes people very happy. Should

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Speaker 3: I think about mass as a third kind of energy.

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Speaker 1: It's tempting, right to think about mass and another kind

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Speaker 1: of energy, because we talked about stored energy, chemical energy,

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Speaker 1: and atp energy stored in protons as they get fused

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Speaker 1: together in the sun. And you hear a lot that

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Speaker 1: mass is another kind of energy. People say equals mc squared, right,

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Speaker 1: and so therefore mass is energy and energy is mass. Yeah,

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Speaker 1: so that's not really true, and the deeper answer is

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Speaker 1: that mass is just an indicator of internal stored energy.

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Speaker 1: Think about some object and you can categorize all of

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Speaker 1: its energy into two different boxes. One is the motion

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Speaker 1: of that object, like, is the whole thing moving? If so,

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Speaker 1: it's got some kinetic energy, right. Cool. The other kind

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Speaker 1: of energy you can have is internal energy, like maybe

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Speaker 1: there's a bunch of particles and they have bonds, or

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Speaker 1: there's chemistry or something. All that internal stored energy is

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Speaker 1: what we call mass. Mass is not a new form

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Speaker 1: of energy. It's not a special kind of energy on

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Speaker 1: its own. It's an indicator of how much energy is

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Speaker 1: stored inside something.

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Speaker 3: Okay, So like if you've got a big truck and

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Speaker 3: a little truck and you set both of them going

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Speaker 3: down the hill, the big truck is going to have

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Speaker 3: more energy because it has more mass, and it's an

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Speaker 3: indicator that it has more energy.

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Speaker 1: But it's yeah, exactly, if you measure the inertia of

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Speaker 1: something right by giving it a push, you give something

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Speaker 1: a certain amount of and then you measure its acceleration.

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Speaker 1: That tells you it's inertia because F equalsma. Then what

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Speaker 1: you're really measuring is how much energy is stored inside something.

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Speaker 1: And you can make this very concrete, like take a

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Speaker 1: rock that has a certain mass, shoot a photon at it.

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Speaker 1: What happens. The photon is absorbed by the rock, and

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Speaker 1: where's that energy go It like goes into the bond somehow,

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Speaker 1: it makes some rock molecule vibrate more, or if it's

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Speaker 1: a gas that you're hitting that it makes those particles

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Speaker 1: move faster. It's some sort of internal energy, right, it

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Speaker 1: doesn't matter. The mass of that rock goes up when

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Speaker 1: it eats that photon, which means like you lie in

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Speaker 1: the sun absorbing photons, your mass goes up. Or you know,

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Speaker 1: you have an electric car parked in your garage and

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Speaker 1: you've plugged it in and now you're adding energy to

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Speaker 1: the battery. Its mass is going up, right, because that

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Speaker 1: mass is an indicator of how much energy is stored

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Speaker 1: inside of whatever kind. As long as it's internal stored energy,

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Speaker 1: it contributes to the mass. So the mass is not

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Speaker 1: on its own. A new kind of energy it's just

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Speaker 1: an d cater of how much energy is stored inside

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Speaker 1: and that's what equals MC squared means. E. There doesn't

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Speaker 1: mean total energy. It's not saying that all mass is

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Speaker 1: energy and all energy is mass. E really means just

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Speaker 1: internal stored energy, and there's a fuller equation that captures

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Speaker 1: the full energy of the object as a term for

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Speaker 1: momentum as well. So it really tells you that energy

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Speaker 1: is internal stored energy as revealed by mass and another

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Speaker 1: term for energy of motion energy of momentum.

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Speaker 3: All right, so mass is just a reflection of kineticum potential.

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Speaker 1: Energy, internal stored energy, which could be kinetic or potential. Yes, absolutely.

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Speaker 3: Okay, are there other forms of energy or are they

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Speaker 3: all essentially just different versions of kinneticum potential energy?

439
00:21:44,720 --> 00:21:46,680
Speaker 1: Period It's a great question and the answer is yes.

440
00:21:46,720 --> 00:21:50,520
Speaker 1: Kineticum potential energy are the two categories of energy, and

441
00:21:50,560 --> 00:21:53,760
Speaker 1: there's nothing else. Right, So everything can be either kinetic

442
00:21:53,840 --> 00:21:57,200
Speaker 1: or potential energy. And if it's internal stored energy, it

443
00:21:57,200 --> 00:21:59,959
Speaker 1: could be kinetic or potential then we call it mass.

444
00:22:00,240 --> 00:22:02,280
Speaker 1: And if it's just motion of the whole object, then

445
00:22:02,280 --> 00:22:06,000
Speaker 1: that's kinetic energy of the whole shebang. And this helps

446
00:22:06,000 --> 00:22:09,080
Speaker 1: you understand things like, well, how can photons have energy

447
00:22:09,119 --> 00:22:10,680
Speaker 1: if they don't have mass. People write to me a

448
00:22:10,720 --> 00:22:13,399
Speaker 1: lot and say, like, photons have energy, right, Well, equals

449
00:22:13,400 --> 00:22:17,840
Speaker 1: empc square, therefore photons have mass, right, Not true, photons

450
00:22:17,880 --> 00:22:21,360
Speaker 1: don't have mass because again that equation equals empc squared.

451
00:22:21,560 --> 00:22:24,439
Speaker 1: That e is just internal stored energy. Photons have no

452
00:22:24,560 --> 00:22:27,760
Speaker 1: internal stored energy because they have no mass. But the

453
00:22:27,760 --> 00:22:30,480
Speaker 1: full equation has a term for momentum in it, and

454
00:22:30,480 --> 00:22:34,800
Speaker 1: photons definitely do have momentum, which is why photons also

455
00:22:34,960 --> 00:22:38,679
Speaker 1: have energy. So you can have energy without having any mass, right,

456
00:22:38,680 --> 00:22:42,399
Speaker 1: because photons again are pure motion energy. And then you

457
00:22:42,440 --> 00:22:45,480
Speaker 1: can play all sorts of fun games to confuse yourself

458
00:22:45,520 --> 00:22:48,320
Speaker 1: by what this means. Like, you know, take a box,

459
00:22:48,520 --> 00:22:51,360
Speaker 1: for example, and shoot a photon in it, and don't

460
00:22:51,400 --> 00:22:54,080
Speaker 1: let the photon get absorbed, put back mirrors inside the box,

461
00:22:54,160 --> 00:22:56,080
Speaker 1: the photon just bounces around. You still just have a

462
00:22:56,080 --> 00:22:58,720
Speaker 1: photon in the box. Then what you've done is you've

463
00:22:58,720 --> 00:23:02,560
Speaker 1: added to the mass of the by adding a massless photon.

464
00:23:02,960 --> 00:23:05,760
Speaker 1: People have this intuition that mass is like the amount

465
00:23:05,800 --> 00:23:08,240
Speaker 1: of stuff in something, but it really isn't. It really

466
00:23:08,280 --> 00:23:11,320
Speaker 1: just captures the internal store energy. Even if you add

467
00:23:11,359 --> 00:23:15,159
Speaker 1: massless things to your box, then you're increasing the mass

468
00:23:15,280 --> 00:23:17,679
Speaker 1: of the box. It's really kind of mind bending. It

469
00:23:17,720 --> 00:23:20,800
Speaker 1: really makes you change your understanding of what mass is.

470
00:23:21,440 --> 00:23:25,679
Speaker 3: I need more coffee, Yeah, but I'm following you. Okay,

471
00:23:25,680 --> 00:23:29,200
Speaker 3: So let's dig in more to this question about you know, when,

472
00:23:29,440 --> 00:23:31,720
Speaker 3: if ever, is energy conserved.

473
00:23:32,440 --> 00:23:33,080
Speaker 2: So you were.

474
00:23:33,000 --> 00:23:35,280
Speaker 3: Talking about throwing a ball in the air and it

475
00:23:35,320 --> 00:23:39,760
Speaker 3: goes from kinetic energy to potential energy, but it doesn't

476
00:23:39,800 --> 00:23:42,280
Speaker 3: always get conserved. Can we talk about the history of

477
00:23:42,320 --> 00:23:44,720
Speaker 3: why we used to think energy was conserved.

478
00:23:45,000 --> 00:23:47,879
Speaker 1: It's a really fascinating story. And you know, for a

479
00:23:47,920 --> 00:23:50,480
Speaker 1: long time we just sort of noticed that energy seemed

480
00:23:50,520 --> 00:23:53,600
Speaker 1: to be conserved. Like if you created a new quantity

481
00:23:53,760 --> 00:23:56,159
Speaker 1: number of ice cream sandwiches or something, and then you

482
00:23:56,359 --> 00:23:59,480
Speaker 1: notice that, weirdly, no matter what you did, the number

483
00:23:59,520 --> 00:24:02,919
Speaker 1: didn't change, Like every time Kelly ate an ice cream sandwich,

484
00:24:02,960 --> 00:24:06,280
Speaker 1: Daniel made one, there was this weird cosmic connection or

485
00:24:06,359 --> 00:24:09,920
Speaker 1: vice versa. Then you'd be like, something is going on here, right,

486
00:24:10,040 --> 00:24:13,639
Speaker 1: Like the universe respects ice cream sandwiches or something.

487
00:24:14,520 --> 00:24:16,040
Speaker 2: I want to live in that use.

488
00:24:17,720 --> 00:24:20,439
Speaker 1: And that's sort of the case for energy. That In

489
00:24:20,520 --> 00:24:24,240
Speaker 1: lots of situations that we studied, energy seems to be conserved,

490
00:24:24,240 --> 00:24:26,600
Speaker 1: and so we assumed that it was same was also

491
00:24:26,640 --> 00:24:29,119
Speaker 1: true for mass. For a long time, people assumed that

492
00:24:29,200 --> 00:24:31,600
Speaker 1: you couldn't create or destroy mass. A lot of people

493
00:24:31,640 --> 00:24:34,040
Speaker 1: still out there repeat that, even though now we know

494
00:24:34,160 --> 00:24:36,640
Speaker 1: that it's not true. We know that you can convert

495
00:24:36,760 --> 00:24:40,320
Speaker 1: mass into energy of motion or into potential energy that's

496
00:24:40,359 --> 00:24:42,879
Speaker 1: not internal. I do that all the time at my

497
00:24:43,040 --> 00:24:45,560
Speaker 1: day job. Right when we smash protons together, we are

498
00:24:45,560 --> 00:24:48,880
Speaker 1: turning their mass into new forms of energy. We're turning

499
00:24:48,920 --> 00:24:51,760
Speaker 1: their energy into mass all the time, back and forth,

500
00:24:52,200 --> 00:24:54,440
Speaker 1: and every time you absorb photons from the Sun, you're

501
00:24:54,480 --> 00:24:57,600
Speaker 1: turning their energy into mass. But that's a hard thing

502
00:24:57,640 --> 00:24:59,879
Speaker 1: to notice unless you have control a tiny part of

503
00:25:00,000 --> 00:25:01,920
Speaker 1: goals and you can see these things happen. Which is

504
00:25:01,960 --> 00:25:05,080
Speaker 1: why chemists for a long time reasonably believed that mass

505
00:25:05,240 --> 00:25:08,160
Speaker 1: was conserved, because they would measure the stuff going into

506
00:25:08,200 --> 00:25:10,200
Speaker 1: a reaction and the stuff coming out of a reaction,

507
00:25:10,400 --> 00:25:14,600
Speaker 1: and they never saw a change to within their measuring uncertainties. Now,

508
00:25:14,680 --> 00:25:17,040
Speaker 1: of course, we know that if they had measured more accurately,

509
00:25:17,320 --> 00:25:19,960
Speaker 1: they would have noticed very tiny changes in mass because

510
00:25:20,119 --> 00:25:22,399
Speaker 1: mass is very very dense stuff. Right. The C square

511
00:25:22,480 --> 00:25:24,359
Speaker 1: there tells you that a big change in energy is

512
00:25:24,400 --> 00:25:28,200
Speaker 1: required to make even a small change in the mass. Anyway,

513
00:25:28,240 --> 00:25:31,159
Speaker 1: the same thing was long true for energy. People are like, okay,

514
00:25:31,160 --> 00:25:33,680
Speaker 1: well mass is not conserved, we're going to give that up.

515
00:25:34,000 --> 00:25:36,399
Speaker 1: But energy still, Energy definitely has got to be a

516
00:25:36,400 --> 00:25:39,320
Speaker 1: conserved right, because people made all these measurements, and it

517
00:25:39,400 --> 00:25:41,800
Speaker 1: seemed like the more accurately you measured it, the more

518
00:25:41,840 --> 00:25:45,240
Speaker 1: you discovered energy had to go somewhere. So in realistic studies,

519
00:25:45,280 --> 00:25:47,760
Speaker 1: for example, say you throw that ball up into the air,

520
00:25:47,920 --> 00:25:50,439
Speaker 1: what's going to happen. Well, it's not going to convert

521
00:25:50,440 --> 00:25:53,000
Speaker 1: all of its kinetic energy into potential because some of

522
00:25:53,040 --> 00:25:55,520
Speaker 1: it's going to get lost to air resistance. Or if

523
00:25:55,560 --> 00:25:57,399
Speaker 1: you roll a ball down a hill, right, some of

524
00:25:57,440 --> 00:25:59,960
Speaker 1: it's going to get lost to friction. That energy seemed

525
00:25:59,960 --> 00:26:02,479
Speaker 1: to creep out of those systems. But as long as

526
00:26:02,480 --> 00:26:04,800
Speaker 1: you define the system to include those things, you account

527
00:26:04,840 --> 00:26:07,840
Speaker 1: for friction and you account for air resistance, you're able

528
00:26:07,880 --> 00:26:11,000
Speaker 1: to account for all of that energy. The balls flying

529
00:26:11,040 --> 00:26:14,000
Speaker 1: up into the air and it loses energy to air resistance,

530
00:26:14,000 --> 00:26:16,400
Speaker 1: but that energy then just goes into heating the air,

531
00:26:17,200 --> 00:26:19,160
Speaker 1: or if you're sliding down a hill and you feel

532
00:26:19,160 --> 00:26:22,400
Speaker 1: friction between your pants and the grass, then you're heating

533
00:26:22,520 --> 00:26:25,560
Speaker 1: up the grass and your pants. That energy is still there.

534
00:26:26,080 --> 00:26:28,560
Speaker 1: And so for a long time people just noticed, even

535
00:26:28,600 --> 00:26:31,240
Speaker 1: with more and more careful accounting, that energy did seem

536
00:26:31,280 --> 00:26:32,040
Speaker 1: to be conserved.

537
00:26:32,320 --> 00:26:36,280
Speaker 3: So I remember that we were talking about Emmy notors on.

538
00:26:36,480 --> 00:26:38,560
Speaker 3: I worked so hard to not say her name during

539
00:26:38,560 --> 00:26:40,879
Speaker 3: the episode because I knew I'd get it wrong, But

540
00:26:40,920 --> 00:26:42,760
Speaker 3: here I went and put myself in that position.

541
00:26:42,840 --> 00:26:44,760
Speaker 2: But anyway, that she had come up with a.

542
00:26:44,680 --> 00:26:49,320
Speaker 3: Really great law or theory that explained when things are

543
00:26:49,320 --> 00:26:52,080
Speaker 3: symmetrical and when they're not. And so it sounds to

544
00:26:52,119 --> 00:26:54,399
Speaker 3: me like we're going to determine here that energy is

545
00:26:54,440 --> 00:26:56,959
Speaker 3: not symmetrical, and that Emmy would tell us that if

546
00:26:56,960 --> 00:26:57,400
Speaker 3: she were here.

547
00:26:57,600 --> 00:26:59,919
Speaker 1: Yeah, it's really cool that we can do more than

548
00:27:00,240 --> 00:27:04,440
Speaker 1: just measure the number of ice cream sandwiches and notice

549
00:27:04,720 --> 00:27:07,119
Speaker 1: that they do or do not change and then conclude something.

550
00:27:07,160 --> 00:27:10,840
Speaker 1: It's not just empirical. We actually now have theoretical ways

551
00:27:11,040 --> 00:27:14,919
Speaker 1: to argue whether something should be conserved or not. And

552
00:27:14,960 --> 00:27:17,520
Speaker 1: as you say, that's due to Emmy Nuther whose name

553
00:27:17,600 --> 00:27:21,280
Speaker 1: I'm sure I'm also mispronouncing, and the number of mispronunciations

554
00:27:21,320 --> 00:27:23,199
Speaker 1: is not conserved. Like it just seems to grow, go

555
00:27:23,320 --> 00:27:25,120
Speaker 1: up and up and up every time I hear this name,

556
00:27:26,560 --> 00:27:30,040
Speaker 1: different pronunciations of it. So German listeners, please don't be

557
00:27:30,080 --> 00:27:32,560
Speaker 1: shy right in and correct our pronunciations. We want to

558
00:27:32,560 --> 00:27:35,520
Speaker 1: get this stuff right anyway. I mean, other told us

559
00:27:35,520 --> 00:27:37,800
Speaker 1: that every time we have a conservation law in the universe.

560
00:27:38,000 --> 00:27:41,440
Speaker 1: You're right, it's connected to some symmetry of the universe.

561
00:27:41,800 --> 00:27:43,919
Speaker 1: And symmetry has a sort of special meaning there. It

562
00:27:43,960 --> 00:27:48,640
Speaker 1: says that you can transform your experiment, you can move

563
00:27:48,680 --> 00:27:50,840
Speaker 1: it or rotate it in some way, and you should

564
00:27:50,920 --> 00:27:54,000
Speaker 1: get the same answer. And so a famous and powerful

565
00:27:54,040 --> 00:27:58,560
Speaker 1: example is momentum conservation. You know, alongside energy, we have

566
00:27:58,640 --> 00:28:02,320
Speaker 1: this concept of moment momentum, which is similar to energy. Right,

567
00:28:02,359 --> 00:28:05,200
Speaker 1: Momentum contributes to your energy. We said, there's internal storat

568
00:28:05,320 --> 00:28:08,240
Speaker 1: energy and then this energy of momentum which come together

569
00:28:08,240 --> 00:28:10,760
Speaker 1: to make your total energy. And the famous and important

570
00:28:10,760 --> 00:28:13,320
Speaker 1: example of that is momentum, which is something that is

571
00:28:13,400 --> 00:28:17,399
Speaker 1: actually conserved in our universe. And when we say symmetry there,

572
00:28:17,520 --> 00:28:20,320
Speaker 1: what we mean is that you can do an experiment

573
00:28:20,520 --> 00:28:24,479
Speaker 1: and then transform the experiment according to some symmetry and

574
00:28:24,680 --> 00:28:26,760
Speaker 1: do the experiment again, you should get the same answer.

575
00:28:27,119 --> 00:28:29,560
Speaker 1: So if you build a physics experiment and you do

576
00:28:29,640 --> 00:28:32,399
Speaker 1: it in space, you know, you collide billiard balls or whatever,

577
00:28:32,880 --> 00:28:35,000
Speaker 1: and then you do it ten meters to the left

578
00:28:35,280 --> 00:28:37,639
Speaker 1: or one hundred meters to the right, or forward one

579
00:28:37,680 --> 00:28:40,600
Speaker 1: thousand meters, you should get the same answer. So that's

580
00:28:40,640 --> 00:28:43,360
Speaker 1: a symmetry of the universe. The universe doesn't care where

581
00:28:43,400 --> 00:28:45,720
Speaker 1: you do your experiment. As long as you set up

582
00:28:45,720 --> 00:28:49,400
Speaker 1: the conditions the same way nearby masses or whatever, you

583
00:28:49,440 --> 00:28:52,680
Speaker 1: should get the same answer. That's a fundamental symmetry of

584
00:28:52,720 --> 00:28:56,520
Speaker 1: the universe. And that symmetry gives you conservation of momentum.

585
00:28:56,760 --> 00:28:59,760
Speaker 1: So Emmy Nuther has this amazing conceptual bridge which you

586
00:28:59,800 --> 00:29:04,280
Speaker 1: tell you what symmetry generates a conservation law. So conservation

587
00:29:04,400 --> 00:29:07,800
Speaker 1: momentum comes from this symmetry of translation, where you don't

588
00:29:07,840 --> 00:29:10,960
Speaker 1: care about where you are in space, where space is relative.

589
00:29:11,040 --> 00:29:14,480
Speaker 1: There's no like official zero, there's no like golden numbers

590
00:29:14,600 --> 00:29:16,880
Speaker 1: glowing in the universe. It doesn't matter where you do

591
00:29:16,960 --> 00:29:20,160
Speaker 1: your experiment. And so now more than just saying hey,

592
00:29:20,240 --> 00:29:23,040
Speaker 1: look I noticed, momentum is conserved. You can say why

593
00:29:23,080 --> 00:29:26,040
Speaker 1: it's conserved, and you can inspect that reason, say does

594
00:29:26,080 --> 00:29:28,480
Speaker 1: that make sense? You know, we can say momentum is

595
00:29:28,480 --> 00:29:32,600
Speaker 1: conserved because the universe has no preferred location. You can

596
00:29:32,640 --> 00:29:34,440
Speaker 1: do your experiment anywhere, and we're like, all right, that

597
00:29:34,480 --> 00:29:36,560
Speaker 1: makes sense and that's a good reason for momentum to

598
00:29:36,560 --> 00:29:40,640
Speaker 1: be conserved. Okay, So what about energy? I mean, not

599
00:29:40,800 --> 00:29:43,840
Speaker 1: there tells us that energy is conserved in the universe

600
00:29:44,360 --> 00:29:49,160
Speaker 1: if the universe's laws don't change with time. Right, So,

601
00:29:49,280 --> 00:29:52,960
Speaker 1: momentum is conserved if the universe's laws don't depend on location,

602
00:29:53,080 --> 00:29:54,720
Speaker 1: if you don't have like different laws of physics in

603
00:29:54,760 --> 00:29:58,520
Speaker 1: different places, Energy is conserved if the laws don't change

604
00:29:58,520 --> 00:30:01,480
Speaker 1: with time. If like this, the same rules of electromagnetism

605
00:30:01,480 --> 00:30:04,720
Speaker 1: applied today and tomorrow and in a thousand years.

606
00:30:05,080 --> 00:30:07,680
Speaker 3: It feels like I want that to be there. But

607
00:30:07,880 --> 00:30:10,480
Speaker 3: I think we've decided that energy is not concerved. Can

608
00:30:10,480 --> 00:30:12,240
Speaker 3: you give me an example of how it's not conserved.

609
00:30:12,680 --> 00:30:15,840
Speaker 1: Yeah, it's fascinating because we assume that the laws of

610
00:30:15,840 --> 00:30:18,880
Speaker 1: physics are constant all the time. Think about just how

611
00:30:18,920 --> 00:30:20,680
Speaker 1: simple it is to read about an experiment in a

612
00:30:20,760 --> 00:30:23,120
Speaker 1: journal and say I'm going to reproduce that experiment and

613
00:30:23,160 --> 00:30:25,200
Speaker 1: see if it's true, and I'm going to do the

614
00:30:25,240 --> 00:30:26,800
Speaker 1: same thing and see if I get the same answer,

615
00:30:26,840 --> 00:30:30,200
Speaker 1: and reproducing it later, and assuming you get the same answer,

616
00:30:30,320 --> 00:30:33,600
Speaker 1: assumes the laws of physics shouldn't change, right, And it's

617
00:30:33,720 --> 00:30:37,280
Speaker 1: really important to our whole process of science that the

618
00:30:37,360 --> 00:30:39,480
Speaker 1: laws of physics were uncovering now are the same as

619
00:30:39,520 --> 00:30:41,959
Speaker 1: they were a thousand years ago or even a billion

620
00:30:42,040 --> 00:30:44,680
Speaker 1: years ago. Like when we look at galaxies deep out

621
00:30:44,720 --> 00:30:47,880
Speaker 1: into space in early times, we assume we know what

622
00:30:47,920 --> 00:30:50,600
Speaker 1: the speed of light was back then, and how mass

623
00:30:50,600 --> 00:30:52,840
Speaker 1: worked and all this kind of stuff. So the universe

624
00:30:52,880 --> 00:30:55,560
Speaker 1: without any constant laws is very difficult the universe to

625
00:30:55,600 --> 00:30:59,000
Speaker 1: do science in, right. And so it's not true that

626
00:30:59,000 --> 00:31:01,360
Speaker 1: the laws of physics are just wially nearly changing with time.

627
00:31:01,440 --> 00:31:04,120
Speaker 1: That's not something we've seen. But there are a couple

628
00:31:04,320 --> 00:31:07,200
Speaker 1: aspects of the laws of physics which do seem to

629
00:31:07,240 --> 00:31:10,320
Speaker 1: be changing with time, and one of them is that

630
00:31:10,360 --> 00:31:15,120
Speaker 1: the universe is expanding, so space itself, the frame in

631
00:31:15,160 --> 00:31:17,680
Speaker 1: which we're doing all of this stuff, is not static.

632
00:31:18,400 --> 00:31:21,000
Speaker 1: And when Emmy Nuther says the universe laws have to

633
00:31:21,080 --> 00:31:24,480
Speaker 1: be constant in time that includes space, right, it means

634
00:31:24,720 --> 00:31:28,320
Speaker 1: space itself needs to be constant the way like conservation

635
00:31:28,400 --> 00:31:31,240
Speaker 1: momentum requires you to be the same location in space,

636
00:31:31,680 --> 00:31:34,560
Speaker 1: it's put in the context of the space in that

637
00:31:34,640 --> 00:31:37,720
Speaker 1: same way, energy conservation requires you to have basically the

638
00:31:37,800 --> 00:31:41,160
Speaker 1: same amount of space. It's not changing the laws of

639
00:31:41,200 --> 00:31:44,400
Speaker 1: electromagnetism or you know, the speed of light or anything.

640
00:31:44,400 --> 00:31:47,280
Speaker 1: It's just saying, hey, the conditions of your experiment are

641
00:31:47,280 --> 00:31:51,640
Speaker 1: not constant because your universe is expanding. And we've known

642
00:31:51,720 --> 00:31:54,560
Speaker 1: for like twenty or so years that the universe is expanding,

643
00:31:54,760 --> 00:31:57,959
Speaker 1: and not just expanding, but accelerating in its expansion, Like

644
00:31:58,360 --> 00:32:01,800
Speaker 1: every year we are making more space between galaxy clusters

645
00:32:02,040 --> 00:32:04,560
Speaker 1: and between ice cream sandwiches and everywhere in the universe.

646
00:32:04,880 --> 00:32:08,400
Speaker 1: Space is expanding. And we actually have a not so

647
00:32:08,520 --> 00:32:12,760
Speaker 1: terrible explanation for why space expanding would mean that energy

648
00:32:12,840 --> 00:32:13,720
Speaker 1: isn't conserved.

649
00:32:14,040 --> 00:32:28,920
Speaker 3: Oh, I want to hear about that after the break.

650
00:32:33,200 --> 00:32:34,080
Speaker 2: All right, we're back.

651
00:32:34,200 --> 00:32:36,480
Speaker 3: So you blew our minds a second ago by explaining

652
00:32:36,480 --> 00:32:39,240
Speaker 3: that the expanding universe is why energy can't be concerned.

653
00:32:39,280 --> 00:32:41,520
Speaker 3: It's crazy to me that something that's happening so far

654
00:32:41,560 --> 00:32:45,240
Speaker 3: away but I guess also happening everywhere is impacting my

655
00:32:45,400 --> 00:32:47,240
Speaker 3: day to day experience of energy.

656
00:32:47,480 --> 00:32:49,080
Speaker 2: But go ahead and tell us the crazy thing you.

657
00:32:49,120 --> 00:32:52,880
Speaker 1: Replaying, William, I think, well, that sounds kind of abstract, right,

658
00:32:52,920 --> 00:32:55,120
Speaker 1: Like you're telling me the universe is expanding, and so

659
00:32:55,240 --> 00:32:58,640
Speaker 1: in some sense the context of our experiments is changing.

660
00:32:59,240 --> 00:33:01,640
Speaker 1: But why does that mean that energy is not conserved?

661
00:33:01,680 --> 00:33:05,320
Speaker 1: Like is energy being created somewhere or destroyed somewhere. So

662
00:33:05,400 --> 00:33:08,120
Speaker 1: let's tack into the details there, Like energy actually is

663
00:33:08,240 --> 00:33:11,920
Speaker 1: being created by the expansion of the universe. We talk

664
00:33:11,960 --> 00:33:15,240
Speaker 1: about the expansion of space as creating more space, right,

665
00:33:15,240 --> 00:33:18,680
Speaker 1: Like the distance between us and some cluster galaxy is growing,

666
00:33:19,120 --> 00:33:21,840
Speaker 1: and not because we're applying some force to accelerate away

667
00:33:21,880 --> 00:33:26,280
Speaker 1: from them. This is just like general relativity. Space is expanding, right,

668
00:33:26,320 --> 00:33:29,160
Speaker 1: We're not measuring any acceleration. They're not measuring any acceleration

669
00:33:29,200 --> 00:33:33,000
Speaker 1: with their accelerometers. But the distance between our galaxies is

670
00:33:33,040 --> 00:33:36,640
Speaker 1: increasing and faster and faster every year. So new space

671
00:33:36,720 --> 00:33:39,040
Speaker 1: is being made. Well, what does that mean? For new

672
00:33:39,080 --> 00:33:42,960
Speaker 1: space to be made? Space is filled with quantum fields, right,

673
00:33:43,240 --> 00:33:46,440
Speaker 1: There's the electron field, there's electromagnetic field, there's fields for

674
00:33:46,480 --> 00:33:49,800
Speaker 1: all the quarks, all these fields in space, and all

675
00:33:49,840 --> 00:33:53,480
Speaker 1: those fields have non zero energy, like these are quantum fields,

676
00:33:53,480 --> 00:33:56,000
Speaker 1: which means they can never go down to total zero.

677
00:33:56,120 --> 00:33:59,960
Speaker 1: They always have some energy in them. So you pop

678
00:34:00,000 --> 00:34:04,000
Speaker 1: a new cube of space, boom, it comes with quantum

679
00:34:04,080 --> 00:34:07,840
Speaker 1: fields that have energy in them. Right, So new space

680
00:34:07,920 --> 00:34:12,160
Speaker 1: means new energy. So right there, making more space means

681
00:34:12,239 --> 00:34:14,600
Speaker 1: you're creating energy, that doesn't It just.

682
00:34:14,520 --> 00:34:17,560
Speaker 3: Mean the energy gets spread more thin across this new space.

683
00:34:17,680 --> 00:34:20,600
Speaker 1: Because every chunk of space is the same and the

684
00:34:20,680 --> 00:34:24,240
Speaker 1: rules of quantum mechanics have a minimum requirement of that energy.

685
00:34:24,840 --> 00:34:27,480
Speaker 1: It's not something we deeply understand, but it's something that's

686
00:34:27,520 --> 00:34:31,319
Speaker 1: required for the accelerated expansion of the universe. We know

687
00:34:31,400 --> 00:34:34,680
Speaker 1: that dark energy behaves this way. We see, for example,

688
00:34:34,719 --> 00:34:38,440
Speaker 1: as the universe expands, the density of dark energy doesn't

689
00:34:38,520 --> 00:34:42,320
Speaker 1: change in the universe like the density of protons goes down.

690
00:34:42,600 --> 00:34:44,759
Speaker 1: You have a certain number of protons, you know, some

691
00:34:44,880 --> 00:34:48,080
Speaker 1: huge number of protons in the universe. As the volume

692
00:34:48,120 --> 00:34:51,440
Speaker 1: of the universe increases, the density of those protons drops

693
00:34:51,480 --> 00:34:54,320
Speaker 1: exactly the way you would expect. Right you double the volume,

694
00:34:54,400 --> 00:34:57,600
Speaker 1: that density goes down by a factor too. But dark energies.

695
00:34:57,680 --> 00:35:01,040
Speaker 1: Density does not decrease. You double the volume, the density

696
00:35:01,080 --> 00:35:03,960
Speaker 1: stays the same. Right, So dark energy behaves in this

697
00:35:04,080 --> 00:35:06,799
Speaker 1: weird way that when you create more space, you also

698
00:35:06,800 --> 00:35:07,920
Speaker 1: create more dark energy.

699
00:35:08,120 --> 00:35:09,040
Speaker 2: Where does it come from?

700
00:35:09,040 --> 00:35:10,439
Speaker 1: Where does it come from? Yeah?

701
00:35:10,640 --> 00:35:11,600
Speaker 2: How does that keep happening?

702
00:35:11,719 --> 00:35:13,840
Speaker 1: You ask where it comes from? And that's a question

703
00:35:13,920 --> 00:35:16,799
Speaker 1: that only makes sense if it's conserved, if it has

704
00:35:16,840 --> 00:35:18,880
Speaker 1: to come from somewhere, right, Like if I make an

705
00:35:18,880 --> 00:35:21,120
Speaker 1: ice cream sandwich, do you say, hey, where did that

706
00:35:21,120 --> 00:35:22,840
Speaker 1: ice cream sandwich come from? That seems to violate the

707
00:35:22,880 --> 00:35:23,560
Speaker 1: loss of physics.

708
00:35:23,920 --> 00:35:26,200
Speaker 3: You're like, no, I wouldn't ask questions about a new

709
00:35:26,239 --> 00:35:28,359
Speaker 3: ice cream sandwich, Dane, I would just enjoy it.

710
00:35:28,640 --> 00:35:30,480
Speaker 1: Right, go on. You know it's true you have to

711
00:35:30,520 --> 00:35:32,720
Speaker 1: assemble it out of bits, But like the assembly itself

712
00:35:32,760 --> 00:35:35,240
Speaker 1: didn't violate some law physics. You didn't have to destroy

713
00:35:35,239 --> 00:35:37,799
Speaker 1: an ice cream sandwich somewhere else to make this one. Right,

714
00:35:38,000 --> 00:35:40,160
Speaker 1: there's no limit on the number of ice cream sandwiches.

715
00:35:40,280 --> 00:35:41,919
Speaker 2: Thank the Lord, hallelujah.

716
00:35:42,040 --> 00:35:45,080
Speaker 1: Yeah, I know, we're all relieved. And so that question

717
00:35:45,120 --> 00:35:47,680
Speaker 1: where does the energy come from? Only make sense if

718
00:35:47,719 --> 00:35:50,680
Speaker 1: things have to flow. If you can just change the

719
00:35:50,719 --> 00:35:53,520
Speaker 1: total energy in the universe or change under ice cream sandwiches.

720
00:35:53,760 --> 00:35:56,880
Speaker 1: Then the question itself isn't actually as meaningful.

721
00:35:57,400 --> 00:36:00,840
Speaker 3: Right, So energy comes from nowhere. Energy can just like poop,

722
00:36:01,120 --> 00:36:01,600
Speaker 3: pop up.

723
00:36:01,800 --> 00:36:05,520
Speaker 1: Energy can just pop up. Yeah, absolutely, and you can

724
00:36:05,560 --> 00:36:06,440
Speaker 1: also disappear.

725
00:36:06,960 --> 00:36:07,160
Speaker 6: Right.

726
00:36:07,640 --> 00:36:10,279
Speaker 1: We talked about how the density of protons changes as

727
00:36:10,280 --> 00:36:12,960
Speaker 1: the universe expands and the density of dark energy. So

728
00:36:13,040 --> 00:36:15,560
Speaker 1: protons dilute in a way that makes a lot of sense, right,

729
00:36:15,640 --> 00:36:18,560
Speaker 1: Like you double the volume, the density goes down by

730
00:36:18,560 --> 00:36:22,320
Speaker 1: a factor of two. Interestingly, side note, same thing is

731
00:36:22,320 --> 00:36:25,400
Speaker 1: true of dark matter dark matter. As you double the

732
00:36:25,480 --> 00:36:28,080
Speaker 1: volume of the universe, dark matter density drops by two,

733
00:36:28,080 --> 00:36:30,399
Speaker 1: which is one reason why we think of dark matter

734
00:36:30,400 --> 00:36:32,919
Speaker 1: as matter, because it dilutes the way it matter does,

735
00:36:33,160 --> 00:36:37,480
Speaker 1: because radiation doesn't photons, As you double the volume of

736
00:36:37,480 --> 00:36:40,799
Speaker 1: the universe, their energy density drops by more than two.

737
00:36:41,560 --> 00:36:43,600
Speaker 1: Like you have a certain number of photons in the universe.

738
00:36:44,080 --> 00:36:46,160
Speaker 1: Now you increase the volume of the universe, you have

739
00:36:46,200 --> 00:36:48,600
Speaker 1: the same number of photons and more volumes. You might think, oh,

740
00:36:48,640 --> 00:36:51,480
Speaker 1: the energy density just decreases because you've increase the volume.

741
00:36:51,960 --> 00:36:56,240
Speaker 1: Not true, because the expansion of space also red shifts

742
00:36:56,360 --> 00:37:01,680
Speaker 1: those photons. It stretches their wavelength to rhetoric or longer wavelengths.

743
00:37:02,000 --> 00:37:05,880
Speaker 1: Longer wavelength means lower energy. So you have a universe

744
00:37:05,920 --> 00:37:09,400
Speaker 1: filled with photons, you expand that universe, their energy density

745
00:37:09,440 --> 00:37:13,319
Speaker 1: drops faster than the energy density of matter or dark matter.

746
00:37:13,760 --> 00:37:17,040
Speaker 1: Where does that energy go? It doesn't have to go anywhere.

747
00:37:17,040 --> 00:37:20,640
Speaker 3: It just goes moves into the space that was just created.

748
00:37:21,480 --> 00:37:23,800
Speaker 2: I've solved it. Where's my Nobel price?

749
00:37:24,200 --> 00:37:26,160
Speaker 1: I love that idea. People are right to be about

750
00:37:26,200 --> 00:37:29,080
Speaker 1: that a lot. They're like, Okay, energy is creative when

751
00:37:29,120 --> 00:37:32,000
Speaker 1: you expand space and also destroyed. Do these two numbers

752
00:37:32,000 --> 00:37:34,600
Speaker 1: add up, And it would be amazing if they did, right,

753
00:37:34,680 --> 00:37:36,799
Speaker 1: And that would be a beautiful explanation, you know, plus

754
00:37:36,880 --> 00:37:39,440
Speaker 1: seven thousand minus seven thousand boom. I think we figured

755
00:37:39,440 --> 00:37:42,680
Speaker 1: it out. These two numbers are vastly different scales. Like

756
00:37:42,719 --> 00:37:45,759
Speaker 1: the energy and photons in the universe is tiny, like

757
00:37:46,120 --> 00:37:48,279
Speaker 1: much less than one percent of all the energy and

758
00:37:48,400 --> 00:37:51,239
Speaker 1: universe is in photons, but the dark energy of the

759
00:37:51,320 --> 00:37:54,319
Speaker 1: universe is like two thirds of all the energy. So

760
00:37:54,480 --> 00:37:58,120
Speaker 1: energy is increasing in dark energy much much more rapidly

761
00:37:58,160 --> 00:38:01,960
Speaker 1: than energy is decreasing by redshift of photons. So we

762
00:38:02,000 --> 00:38:04,279
Speaker 1: don't think that photons are like getting turned into dark

763
00:38:04,360 --> 00:38:05,160
Speaker 1: energy or anything.

764
00:38:05,480 --> 00:38:09,040
Speaker 3: Okay, So bottom line here, we don't know where energy

765
00:38:09,080 --> 00:38:15,240
Speaker 3: comes from. We know it's not conserved. Physicists have job security.

766
00:38:16,000 --> 00:38:18,440
Speaker 1: Yeah, we don't even really still have an answer to

767
00:38:18,520 --> 00:38:22,480
Speaker 1: the original question of like what is energy? Right, still

768
00:38:23,000 --> 00:38:26,000
Speaker 1: a description of something we've seen, and we have a

769
00:38:26,080 --> 00:38:29,120
Speaker 1: little bit more theoretical footing now because we could, in

770
00:38:29,120 --> 00:38:32,600
Speaker 1: principle define energy as the thing that would be conserved

771
00:38:32,840 --> 00:38:36,200
Speaker 1: if the laws of physics were perfectly symmetric in time. Right,

772
00:38:36,239 --> 00:38:39,240
Speaker 1: you can use Nuther's theorem as a definition of energy

773
00:38:39,280 --> 00:38:42,759
Speaker 1: and say, oh, energy is that thing which would be conserved.

774
00:38:42,800 --> 00:38:44,920
Speaker 1: And that's kind of cool. I like that. It is

775
00:38:45,000 --> 00:38:47,400
Speaker 1: very theoretically grounded, but it doesn't give you like a

776
00:38:47,400 --> 00:38:51,200
Speaker 1: conceptual sense for like what is this thing? But unfortunately

777
00:38:51,200 --> 00:38:53,680
Speaker 1: that sort of turns you back to the philosophy of it, like, well,

778
00:38:53,719 --> 00:38:55,520
Speaker 1: what do you mean what is this thing? What kind

779
00:38:55,560 --> 00:38:58,600
Speaker 1: of answer are you looking for when you ask what

780
00:38:58,760 --> 00:39:02,520
Speaker 1: is energy? Part of the question is not satisfied by like, well,

781
00:39:02,560 --> 00:39:04,880
Speaker 1: here's the description of the kinds of energy, here are

782
00:39:04,920 --> 00:39:07,600
Speaker 1: the rules that it follows. Here's how it's created, here's

783
00:39:07,600 --> 00:39:10,560
Speaker 1: how it's destroyed. Here's how it's not concerned. But part

784
00:39:10,560 --> 00:39:13,320
Speaker 1: of the question is not answered by that description.

785
00:39:13,440 --> 00:39:15,600
Speaker 2: Do you think I have no idea?

786
00:39:16,000 --> 00:39:19,560
Speaker 1: Yeah, I feel like there's something about it that's still unsatisfied,

787
00:39:19,600 --> 00:39:22,040
Speaker 1: that's still like yeah, but what is it? You know, like,

788
00:39:22,080 --> 00:39:23,840
Speaker 1: why do we have it? Where does it come from?

789
00:39:24,440 --> 00:39:26,960
Speaker 1: It's a deep human question, but like the human questions

790
00:39:26,960 --> 00:39:30,480
Speaker 1: we ask, aren't always the appropriate questions, aren't always the

791
00:39:30,480 --> 00:39:33,920
Speaker 1: ones that answer the question. Sometimes we discover that something

792
00:39:34,000 --> 00:39:36,719
Speaker 1: is different from how we expected it to behave and

793
00:39:36,760 --> 00:39:38,560
Speaker 1: that means the kind of questions we should ask about

794
00:39:38,600 --> 00:39:43,520
Speaker 1: it are changing. Because energy isn't something that comes from somewhere.

795
00:39:43,560 --> 00:39:46,360
Speaker 1: It's a feature of the universe, and it does seem

796
00:39:46,360 --> 00:39:50,040
Speaker 1: to be important because under lots of context it is conserved,

797
00:39:50,640 --> 00:39:52,560
Speaker 1: but it's not fundamental in that way, and so it

798
00:39:52,560 --> 00:39:56,120
Speaker 1: could just be something that humans notice, something the humans

799
00:39:56,239 --> 00:39:59,239
Speaker 1: like to calculate, something that connects with our everyday experience

800
00:39:59,400 --> 00:40:01,920
Speaker 1: in a way that it's important to us, but isn't

801
00:40:02,120 --> 00:40:04,480
Speaker 1: Like alien physicists, for example.

802
00:40:04,280 --> 00:40:08,240
Speaker 3: It only appears to be conserved on human scales because

803
00:40:08,880 --> 00:40:11,280
Speaker 3: it's being lost at such low numbers it's hard to measure,

804
00:40:11,320 --> 00:40:14,160
Speaker 3: but it's not even conserved on small scales.

805
00:40:14,200 --> 00:40:14,879
Speaker 2: It just looks that way.

806
00:40:14,960 --> 00:40:17,799
Speaker 1: Yeah, that's exactly right. And I think it's useful to

807
00:40:17,800 --> 00:40:20,120
Speaker 1: think about this because it impacts other questions we have.

808
00:40:20,680 --> 00:40:23,719
Speaker 1: Like a lot of listeners who wrote in Thought about

809
00:40:23,719 --> 00:40:26,080
Speaker 1: the conservation of energy, and it talked about how the

810
00:40:26,080 --> 00:40:29,680
Speaker 1: Big Bang had energy, and maybe all the energy in

811
00:40:29,680 --> 00:40:32,759
Speaker 1: the universe just came from the Big Bang, right, And

812
00:40:32,840 --> 00:40:35,600
Speaker 1: so I hope the answer today reveals that, like, no,

813
00:40:35,760 --> 00:40:38,160
Speaker 1: there's some energy in the universe which was created after

814
00:40:38,239 --> 00:40:40,480
Speaker 1: the Big Bang. Right, This expansion of the universe is

815
00:40:40,520 --> 00:40:43,160
Speaker 1: making energy, and that's post Big Bang energy. And also

816
00:40:43,280 --> 00:40:45,560
Speaker 1: some of the energy of the Big Bang is gone now.

817
00:40:46,360 --> 00:40:48,040
Speaker 1: Like you have the Big Bang, you have matter and

818
00:40:48,080 --> 00:40:51,440
Speaker 1: anti matter created, they annihilate. You have a universe mostly

819
00:40:51,480 --> 00:40:54,960
Speaker 1: filled briefly with photons. So photons did dominate the universe

820
00:40:55,040 --> 00:40:58,399
Speaker 1: energy budget initially, but a lot of those photons are

821
00:40:58,440 --> 00:41:02,279
Speaker 1: now red shifted and their energy is gone. Like we

822
00:41:02,320 --> 00:41:04,640
Speaker 1: talk on the podcast a lot about the cosmic microwave

823
00:41:04,680 --> 00:41:08,160
Speaker 1: background radiation, this energy from the early universe that reveals

824
00:41:08,200 --> 00:41:10,839
Speaker 1: so much about how the universe came together and what

825
00:41:10,880 --> 00:41:13,680
Speaker 1: it means and how it rippled. But those photons are

826
00:41:13,800 --> 00:41:16,479
Speaker 1: very very red. They're at a temperature of like two

827
00:41:16,480 --> 00:41:20,279
Speaker 1: point seven calvin, very very cold. The plasma that made

828
00:41:20,320 --> 00:41:24,319
Speaker 1: them was like three hundred thousand degrees calvin. Right, they

829
00:41:24,360 --> 00:41:26,760
Speaker 1: were a glow of them, a very very hot plasma,

830
00:41:26,920 --> 00:41:31,640
Speaker 1: very energetic photons. Originally that energy is just gone now right,

831
00:41:31,760 --> 00:41:34,680
Speaker 1: It didn't go anywhere. So a lot of the energy

832
00:41:34,719 --> 00:41:36,440
Speaker 1: in the universe didn't come from the Big Bang, and

833
00:41:36,480 --> 00:41:38,359
Speaker 1: a lot of the energy of the Big Bang is

834
00:41:38,400 --> 00:41:39,719
Speaker 1: now gone, it's fizzled out.

835
00:41:40,000 --> 00:41:43,080
Speaker 3: Do we have less energy over time, more energy over time,

836
00:41:43,160 --> 00:41:45,080
Speaker 3: or do we not know how this balance is working out.

837
00:41:45,360 --> 00:41:47,920
Speaker 1: We definitely have more energy over time because dark energy

838
00:41:47,960 --> 00:41:51,760
Speaker 1: is much more dramatic, and so all the energy created

839
00:41:51,880 --> 00:41:56,080
Speaker 1: by dark energy, the expansion of the universe vastly outweighs

840
00:41:56,440 --> 00:41:59,480
Speaker 1: the energy loss due to red shifts of photons.

841
00:42:00,000 --> 00:42:00,880
Speaker 2: You would said that earlier.

842
00:42:00,920 --> 00:42:04,240
Speaker 3: But is that the only way that energy is lost

843
00:42:04,360 --> 00:42:06,480
Speaker 3: or is energy lost while humans are doing all of

844
00:42:06,520 --> 00:42:09,640
Speaker 3: these reactions down here, and is that impacting the like

845
00:42:09,800 --> 00:42:11,200
Speaker 3: mass balance equation.

846
00:42:10,920 --> 00:42:11,680
Speaker 2: For the universe?

847
00:42:12,880 --> 00:42:15,359
Speaker 1: To my knowledge, the expansion of the universe is the

848
00:42:15,400 --> 00:42:18,520
Speaker 1: only source of energy gain or loss. Right, You noticed

849
00:42:18,520 --> 00:42:20,640
Speaker 1: that it's an underlying mechanism for both of these things,

850
00:42:20,680 --> 00:42:23,919
Speaker 1: because it's the place that Norther's theorem is violated, right,

851
00:42:24,239 --> 00:42:26,600
Speaker 1: It's the thing that doesn't respect the time symmetry. So

852
00:42:26,640 --> 00:42:30,480
Speaker 1: the expansion of the universe redshifts those photons, breaking conservation

853
00:42:30,520 --> 00:42:34,160
Speaker 1: of energy and creates news space breaking conservation of energy.

854
00:42:34,400 --> 00:42:37,320
Speaker 1: So anything that's sensitive to the expansion of the universe

855
00:42:37,719 --> 00:42:41,920
Speaker 1: can be a source of the violation of conservation of energy.

856
00:42:42,400 --> 00:42:44,319
Speaker 1: And I want to make another comment about the Big Bang,

857
00:42:44,360 --> 00:42:46,560
Speaker 1: which is it seems like a little bit of a

858
00:42:46,640 --> 00:42:50,760
Speaker 1: loss of power to explain and explore, Like if energy

859
00:42:50,840 --> 00:42:52,759
Speaker 1: was conserved, then we could do this cool thing of

860
00:42:52,800 --> 00:42:55,120
Speaker 1: tracing it back into the Sun and then where that

861
00:42:55,160 --> 00:42:56,719
Speaker 1: came from, where that came from, all the way back

862
00:42:56,760 --> 00:42:59,200
Speaker 1: to the Big Bang. It's like we have a ledger,

863
00:42:59,400 --> 00:43:02,520
Speaker 1: you know, the tell us how energy slashes around, and

864
00:43:02,560 --> 00:43:05,239
Speaker 1: maybe by tracing that we could learn something. And that

865
00:43:05,320 --> 00:43:07,280
Speaker 1: seems really cool, and it feels like, oh, oh, maybe

866
00:43:07,280 --> 00:43:09,800
Speaker 1: we've lost that. Maybe we can no longer learn about

867
00:43:09,800 --> 00:43:12,960
Speaker 1: the Big Bang by studying energy. Well, just now we

868
00:43:13,000 --> 00:43:15,960
Speaker 1: can ask different questions, you know, we can ask how

869
00:43:16,040 --> 00:43:18,719
Speaker 1: the energy for the Big Bang came about, Like we

870
00:43:18,840 --> 00:43:22,280
Speaker 1: know that the universe was filled with hot, frothing energy

871
00:43:22,360 --> 00:43:25,400
Speaker 1: early on. Where did that come from? We no longer

872
00:43:25,440 --> 00:43:27,319
Speaker 1: have to just answer that by saying, oh, it came

873
00:43:27,320 --> 00:43:29,960
Speaker 1: from this other thing with equal energy. Now we have

874
00:43:30,040 --> 00:43:32,960
Speaker 1: more ideas about how you can create all that energy

875
00:43:33,400 --> 00:43:36,800
Speaker 1: from some earlier denser states. So, if anything, it opens

876
00:43:36,920 --> 00:43:39,680
Speaker 1: up the examination to think differently about the origin of

877
00:43:39,719 --> 00:43:41,719
Speaker 1: the universe. And you know, that's what we want. We

878
00:43:41,800 --> 00:43:44,480
Speaker 1: want our understanding of physics to evolve and to give

879
00:43:44,560 --> 00:43:47,520
Speaker 1: us new ways to think about the whole context of

880
00:43:47,680 --> 00:43:50,680
Speaker 1: reality and where it all came from. And so to me,

881
00:43:50,800 --> 00:43:53,960
Speaker 1: that's exciting. It like removes blinders a little bit and

882
00:43:54,080 --> 00:43:57,400
Speaker 1: gives us a broader sense for how the universe works

883
00:43:57,440 --> 00:43:59,040
Speaker 1: and maybe how it all started.

884
00:43:59,560 --> 00:44:02,359
Speaker 3: I bet you are great at writing grants. Okay, we

885
00:44:02,360 --> 00:44:04,560
Speaker 3: were wrong about that, but that's okay, because it's the

886
00:44:04,680 --> 00:44:07,160
Speaker 3: fascinating thing is actually revealed now.

887
00:44:08,120 --> 00:44:09,920
Speaker 1: So please send me a million dollars to make a

888
00:44:09,920 --> 00:44:11,719
Speaker 1: lot of ice cream sandwiches, because I have a lot

889
00:44:11,760 --> 00:44:12,560
Speaker 1: to learn.

890
00:44:12,760 --> 00:44:15,680
Speaker 3: You know, please share those ice cream sandwiches. Daniel, Yes,

891
00:44:15,760 --> 00:44:16,719
Speaker 3: Daniel needs this money.

892
00:44:16,719 --> 00:44:21,120
Speaker 1: It's important, everybody exactly. My cookies and cream project really

893
00:44:21,600 --> 00:44:23,960
Speaker 1: top priority for national security.

894
00:44:24,719 --> 00:44:27,279
Speaker 2: That's right, that's right, all right.

895
00:44:27,360 --> 00:44:31,239
Speaker 3: Well, I learned a ton today actually, and I can't

896
00:44:31,239 --> 00:44:33,239
Speaker 3: wait to tell my daughter actually about some of this

897
00:44:33,280 --> 00:44:34,720
Speaker 3: stuff and blow her mind somehow.

898
00:44:34,719 --> 00:44:36,440
Speaker 2: I feel like she's going to find this really interesting.

899
00:44:36,560 --> 00:44:39,720
Speaker 1: Yeah. So energy is not conserved, which means it doesn't

900
00:44:39,719 --> 00:44:43,360
Speaker 1: have to con from anywhere. But our understanding does seem

901
00:44:43,400 --> 00:44:45,239
Speaker 1: to be growing, and it seems to em and a

902
00:44:45,320 --> 00:44:47,960
Speaker 1: from these deep studies of how the universe works. So

903
00:44:48,440 --> 00:44:49,359
Speaker 1: let's keep doing that.

904
00:44:49,440 --> 00:44:53,640
Speaker 3: Let's hope our understanding is expanding faster than the information

905
00:44:53,680 --> 00:44:54,200
Speaker 3: we're losing.

906
00:44:55,480 --> 00:44:57,720
Speaker 1: All right, go off and enjoy ice cream sandwich. Everyone

907
00:44:57,840 --> 00:44:58,279
Speaker 1: on us?

908
00:44:58,560 --> 00:45:00,799
Speaker 2: Oh, not on us, Not on us, Daniel.

909
00:45:00,480 --> 00:45:02,839
Speaker 1: Virtually on us, spiritually on us.

910
00:45:03,239 --> 00:45:04,440
Speaker 2: Don't send us three sets.

911
00:45:04,719 --> 00:45:06,440
Speaker 1: That's all right, emotionally on us.

912
00:45:06,520 --> 00:45:08,320
Speaker 2: There you go, Okay.

913
00:45:15,400 --> 00:45:18,920
Speaker 3: Daniel and Kelly's Extraordinary Universe is produced by iHeartRadio.

914
00:45:19,160 --> 00:45:21,680
Speaker 2: We would love to hear from you, We really would.

915
00:45:21,840 --> 00:45:24,600
Speaker 1: We want to know what questions you have about this

916
00:45:24,800 --> 00:45:26,480
Speaker 1: Extraordinary Universe.

917
00:45:26,600 --> 00:45:29,560
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918
00:45:29,560 --> 00:45:32,560
Speaker 3: for future shows. If you contact us, we will get

919
00:45:32,600 --> 00:45:33,000
Speaker 3: back to you.

920
00:45:33,200 --> 00:45:36,719
Speaker 1: We really mean it. We answer every message. Email us

921
00:45:36,760 --> 00:45:39,600
Speaker 1: at Questions at danieland Kelly dot org.

922
00:45:39,840 --> 00:45:41,080
Speaker 2: You can find us on social media.

923
00:45:41,200 --> 00:45:45,000
Speaker 3: We have accounts on x, Instagram, Blue Sky and on

924
00:45:45,080 --> 00:45:46,000
Speaker 3: all of those platforms.

925
00:45:46,040 --> 00:45:49,000
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926
00:45:49,120 --> 00:45:50,640
Speaker 1: Don't be shy right to us.