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Speaker 1: There are so many topics in physics that are hard

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Speaker 1: to grapple with to deeply understand, and it's not helped

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Speaker 1: by the fact that often physicists have given these things

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Speaker 1: confusing names. Electrons, for example, have quantum spin, but they're

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Speaker 1: not actually spinning. Moments of inertia have nothing to do

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Speaker 1: with moments of time. Work and power have very different

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Speaker 1: meanings in physics and in English. But sometimes even when

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Speaker 1: physicists invent a brand new word to convey a new idea,

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Speaker 1: it's still slippery to grasp. So today in the pod,

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Speaker 1: we're going to try to grab hold of one of

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Speaker 1: the trickiest concepts in physics, one that's often tossed about

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Speaker 1: and attached to a simple explanation, but whose subtle power

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Speaker 1: isn't usually clearly explained. Today in the pod, we are

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Speaker 1: tackling entropy. What is it? Does it explain why our

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Speaker 1: teenager's rooms are so messy, or why coffee spills out

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Speaker 1: of cups but not back into them. Does it tell

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Speaker 1: us about the fate of the universe or the nature

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Speaker 1: of time? Is it about order and chaos? Why did

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Speaker 1: physicists even devise this concept? Welcome to Daniel and Kelly's

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Speaker 1: Extraordinarily Disorderly Universe.

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Speaker 2: Hello. My name is Kelly Wiener Smith, and I often

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Speaker 2: make jokes about entropy increasing in my home, and today

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Speaker 2: I'm gonna find out if that joke is scientifically accurate

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Speaker 2: or not. Hi.

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Speaker 1: I'm Daniel. I'm a particle a physicists, and I think

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Speaker 1: that there's always one person in the marriage who's more

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Speaker 1: orderly and one person is more chaotic.

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Speaker 2: Yeah, it's pretty easy to identify who's who in my marriage.

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Speaker 2: Are you the more orderly or the more chaotic in

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Speaker 2: your marriage? Katrina seems pretty orderly, but so do you.

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Speaker 1: I don't want to slander my wife on air, especially

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Speaker 1: if she's not here to defend herself, so I'll say

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Speaker 1: that in some categories, I'm more orderly, and in some categories,

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Speaker 1: she's more on top of stuff, and that's why we're

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Speaker 1: such a good team.

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Speaker 2: Ah, I'm going to slander my husband. He's the chaotic

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Speaker 2: force in our family, he absolutely is. But he's also,

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Speaker 2: you know, a lot of the creative force. So it

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Speaker 2: works out.

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Speaker 1: Yeah, exactly. Well. The yin and yang is what makes

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Speaker 1: it exciting, isn't it.

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Speaker 2: It keeps things fresh, that's for sure. So I was

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Speaker 2: thinking about the topic for today, and when I think

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Speaker 2: about entropy, the first thing that comes to mind is

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Speaker 2: jazz music. And when I googled entropy and jazz, actually

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Speaker 2: a lot of things came up. People have like studied

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Speaker 2: jazz music through the lens of entropy. Do you like

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Speaker 2: jazz music? What do you think?

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Speaker 1: Wow, that's fascinating. I never connected entropy and jazz music.

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Speaker 1: There's some jazz music I like, but I like things

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Speaker 1: that are a little bit more melodic. So just like

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Speaker 1: a wandering sprinkle of nodes doesn't do it for me.

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Speaker 1: I need a little bit of rhythm and some beat

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Speaker 1: to it and whatever. So I'm more of a blues

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Speaker 1: guy than jazz, how about you.

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Speaker 2: It depends on my mood. There are some moods that

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Speaker 2: I'm in where jazz is exactly what I want and

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Speaker 2: it's exactly what I need to listen to while I'm writing.

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Speaker 2: And then there's other moods where it does make me

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Speaker 2: feel kind of frustrated and overwhelmed. So, but you know,

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Speaker 2: I feel that way for a lot of different kinds

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Speaker 2: of music. I've got like very particular kinds of music

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Speaker 2: for different kinds of moods.

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Speaker 1: I appreciate the jazz nerds though, because they help me

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Speaker 1: understand how almost any human endeavor there are so many

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Speaker 1: layers to it, you know, like people who appreciate wine

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Speaker 1: and they can tell the difference between like a five

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Speaker 1: hundred dollars bottle of wine and a five thousand dollars

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Speaker 1: bottle of wine, whereas like I can't tell the difference

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Speaker 1: between ten dollars and twenty dollars bottles of wine, Or

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Speaker 1: like how many levels of skale there are two chess,

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Speaker 1: you know, where like a level twenty person will be

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Speaker 1: the level eighteen person will be the level seventeen person. Consistently.

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Speaker 1: I feel that same way about jazz, because people talk

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Speaker 1: about it and they're like, Wow, this guy is a

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Speaker 1: genius and so amazing in this way and that way,

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Speaker 1: and I'm just like at the beginning of a journey

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Speaker 1: of appreciating that. But I love when human culture goes

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Speaker 1: really deep on something and people could appreciate the fine

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Speaker 1: nuances of it.

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Speaker 2: Yeah, you know, if I had endless time and money,

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Speaker 2: I would love to just like jump into different cultures

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Speaker 2: and just sort of like appreciate and absorb, you know,

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Speaker 2: the various features that are exciting to them and just

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Speaker 2: sort of enjoy their culture for a little while. And

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Speaker 2: I very briefly jumped into jazz as I've had different

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Speaker 2: friends who do jazz things and it's a very cool culture.

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Speaker 2: But I am still at the early phases of like

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Speaker 2: what is good? I don't know. I just know that

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Speaker 2: this makes me smile.

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Speaker 1: Well, something I do have very strong opinions about because

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Speaker 1: I spent a lot of time perfecting my tastes about

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Speaker 1: it is pizza making. I'm an at home pizza maker,

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Speaker 1: and I have like strong opinions about like, you know,

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Speaker 1: the stretchiness of the dough and the puffiness of the

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Speaker 1: crust and the darkness of the sauce and whatever, because

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Speaker 1: I've made a lot of pizzas in my house, so

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Speaker 1: I know like exactly what I like in a pizza.

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Speaker 1: What have you nerded out on? What are you like

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Speaker 1: a level twenty expert in?

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Speaker 2: Hmm? Well, so first I'll say that my husband also

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Speaker 2: nerds out on pizza, which is making me wonder if

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Speaker 2: we sh make pizza when you're here to visit or

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Speaker 2: if we shouldn't. Uh oh, Zach and I will have

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Speaker 2: a discussion about that. What am I a level twenty

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Speaker 2: nerd on. I don't know. I guess I'm sort of

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Speaker 2: a generalist. I like lots of things. I mean, I'm

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Speaker 2: really into the moths in our area, and I spent

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Speaker 2: two years learning about Russian and Russian culture and like

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Speaker 2: the language. But I don't know if I'm like a

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Speaker 2: level twenty on either one.

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Speaker 1: Of those things. Well, I can tell you moths not

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Speaker 1: very good on pizza. I mean they're delicious, but really

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Speaker 1: not a popular topic.

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Speaker 2: No, I totally believe that. But I've pulled us far

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Speaker 2: from our topic. Today. We're talking about entropy, and you know,

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Speaker 2: I think first we should find out what our audience

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Speaker 2: thinks entropy means.

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Speaker 1: That's right, let's try to beat back the chaos and

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Speaker 1: stay on topic today, Kelly good luck. So I went

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Speaker 1: out there and I asked folks what they thought entropy was,

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Speaker 1: because I was curious what connections people had made in

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Speaker 1: their minds. Maybe they'll also connect it to jazz or

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Speaker 1: blues or pizza making or moth loving. Let's hear what

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Speaker 1: folks had to say. The tendency of a closed system

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Speaker 1: to kind of go from order to disorder unless you

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Speaker 1: add energy to go from order to disorder only I

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Speaker 1: had my head around it.

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Speaker 2: Entropy is a measure of the remaining free energy in

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Speaker 2: a specific.

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Speaker 1: Volume homogene as milk toast, a description of the state

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Speaker 1: of a system in terms of its energy. The more

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Speaker 1: different configurations the system can have and be in the

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Speaker 1: same state, the higher the entropy it has. Matter being

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Speaker 1: either organized or being in a chaotic state, the degree

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Speaker 1: of disorder and a physical system.

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Speaker 2: The amount of energy in a system that can't.

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Speaker 1: Be recovered, describes the level of organization.

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Speaker 2: As time progresses, entropy progresses.

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Speaker 1: I think it's the tendency of energy to spread out

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Speaker 1: slow crawl towards simplicity that the universe imposes on everything. Disorder,

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Speaker 1: aos the absence of order. Things degrade over time. It

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Speaker 1: feels weird because that seems made up what disorder is

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Speaker 1: and what order is. Or if there are more configurations,

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Speaker 1: the entropy is higher number of micro states of the system,

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Speaker 1: which can result in the current macro state.

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Speaker 2: Things want to move from a higher embodied energy state

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Speaker 2: to a lower one. Well, no pizza in those answers,

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Speaker 2: but actually a lot of variety in the answers there.

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Speaker 1: Yeah, I think we really capture something here that there's

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Speaker 1: a general sense that entropy goes up and that it

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Speaker 1: has to do something with order and disorder, but also

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Speaker 1: that there are multiple concepts of entropy. Right, this sensitive

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Speaker 1: energy and entropy and a sense of organization related to entropy.

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Speaker 1: And so I think that captures like the big chaotic

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Speaker 1: confusion that is most people's understanding of what entropy actually is.

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Speaker 2: I do think this idea has escaped into like the

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Speaker 2: general consciousness, and maybe it has disconnected from its physics

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Speaker 2: definitions in that process.

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Speaker 1: Yeah, I think you see a lot of tech bros

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Speaker 1: on social media using enterpa if they know what it means.

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Speaker 2: I mean, it's nowhere near as bad as the word quantum.

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Speaker 2: But let's clear things up today exactly.

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Speaker 1: It's getting there, though.

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Speaker 2: It's getting there, all right. So tell me about the

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Speaker 2: first time the word entropy was used.

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Speaker 1: Yeah, entropy is a fun topic because it's not an

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Speaker 1: ancient topic. Right. People have been talking about motion and

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Speaker 1: velocity and energy and time since people have been like

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Speaker 1: smoking whatever and sitting in caves and looking up at

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Speaker 1: the night sky and wondering how the universe.

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Speaker 2: Works, the things that bring us all together.

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Speaker 1: Yeah, so you can go back and look at the

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Speaker 1: Sumerians thinking about the path of the planets and the

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Speaker 1: length of the year, and you know, the structure of

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Speaker 1: the Solar system and stuff like that. But entropy is

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Speaker 1: a recent concept. It's less than two hundred years old.

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Speaker 1: It's a word that was invented fairly recently as people

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Speaker 1: were puzzling over engines and wheels and energy.

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Speaker 2: Oh so was the idea that, like, it's hard to

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Speaker 2: keep an engine working because entropy sort of overtime makes

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Speaker 2: the system less reliable or tell me more about this history.

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Speaker 1: Yes, so it's the early eighteen hundreds and there's the

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Speaker 1: Carnea cycle and so this French physicist Carno actually a

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Speaker 1: father's son team we're thinking about engines and heat and

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Speaker 1: there was sort of a mystery at the time, like

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Speaker 1: what is heat? Anyway, people had the sense that the

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Speaker 1: universe had a microscopic explanation that could help you understand

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Speaker 1: the macroscopic view, like you know, this is around the

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Speaker 1: time when we're about to get Dalton and thinking about

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Speaker 1: the existence of atoms. So that idea is out there

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Speaker 1: that like maybe this microscopic stuff, you know, and also

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Speaker 1: biologically right, like the germ theory is coming out around

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Speaker 1: this time, you know, within decades at least, so people

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Speaker 1: were wondering, like, what is heat? Is heat like a particle,

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Speaker 1: is it a substance? Does it flow from one thing

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Speaker 1: to the other. Remember early ideas of like electric charge,

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Speaker 1: where like there were two of them and they were

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Speaker 1: a liquid and they flowed. So this is sort of

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Speaker 1: like an idea that was out there. People were wondering,

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Speaker 1: how do engines work? What is energy? What is heat?

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Speaker 1: How are they all related? And in eighteen twenty four

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Speaker 1: Carnot put his finger on this idea that differences in

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Speaker 1: heat can be used to do useful stuff like if

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Speaker 1: you have something that's hot and something that's cold, energy

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Speaker 1: will flow from the hot thing to the cold thing,

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Speaker 1: and you can use that to do stuff sort of

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Speaker 1: like the way water flows from uphill to downhill, and

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Speaker 1: if you capture that flow, you put like a water

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Speaker 1: wheel there. You can use that to do stuff like

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Speaker 1: grind your wheat into flour. Right, very useful. But if

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Speaker 1: the water is all flat, you can't use it to

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Speaker 1: do anything. And so heat differences can be used to

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Speaker 1: produce work. That's Carno's big insight in the early eighteen.

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Speaker 2: Hundreds, did we have the steam engine at this point.

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Speaker 1: Yet, yeah, steam engines existed at this point, and that's

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Speaker 1: a great example of how you use heat. Right, you

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Speaker 1: heat the steam, it rises, it turns your turbine. You

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Speaker 1: can use that to do work or these days to

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Speaker 1: make electricity. Right, and so Carne understood that engines can

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Speaker 1: do this, engines can turn heat differences into work. But

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Speaker 1: he describes sort of a perfect engine one where you

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Speaker 1: can turn heat differences into work, and then you could

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Speaker 1: use that work to create heat differences, so back and

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Speaker 1: forth and back and forth and sort of perfectly without

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Speaker 1: any loss. But he also had this idea that, well,

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Speaker 1: sometimes you have imperfect engines, that something is lost, creeps

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Speaker 1: out of your cycle. This is an imperfect engine. Eventually

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Speaker 1: it'll wind down, you'll turn a heat difference into work,

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Speaker 1: and then you'll turn that work into a heat difference.

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Speaker 1: But you get a little bit less, sort of like

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Speaker 1: the way if you drop a ball. In principle, the

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Speaker 1: potential energy the ball turns into kinetic energy and then

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Speaker 1: it bounces back up and it regains all of that

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Speaker 1: potential energy. But in practice there's a little bit of

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Speaker 1: friction and there's losses in the system, and the ball

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Speaker 1: doesn't bounce forever, right, in the same way. He understood

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Speaker 1: that this happened, but he didn't describe it mathematically. It

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Speaker 1: wasn't for a few more decades that people sort of

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Speaker 1: described this with equations and sort of more mathematical concepts.

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Speaker 2: Okay, but even today, we don't have a perfect engine, right,

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Speaker 2: all of our engines are imperfect.

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Speaker 1: All of our engines are imperfect. Exactly. And it was

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Speaker 1: Claussius who sounds like he's it would be an ancient

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Speaker 1: Greek guy he does, I know, yeah, exactly. I imagine

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Speaker 1: him in a robe, even though he probably just wore

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Speaker 1: a suit and had a top hat. But Classius defined

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Speaker 1: it mathematically, and he thought of it as the stuff

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Speaker 1: that's flowing, like entropy is leaving the system, it's moving

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Speaker 1: through It's like a physical thing. And he connected it

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Speaker 1: to temperature. And so his contribution was essentially invent this

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Speaker 1: concept of entropy to help us understand why some engines

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Speaker 1: are imperfect. And he thought of it as a thing

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Speaker 1: which flows to the system, like a real physical thing,

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Speaker 1: not just like hey, here's a number, we're calculating it.

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Speaker 1: We define it like you could invent anything, right, you

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Speaker 1: could invent the jigiblions and define it as like the

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Speaker 1: number of apples in the universe minus the number of

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Speaker 1: ice cream cones. And that doesn't necessarily have to mean anything, right,

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Speaker 1: But sometimes you invent a number and it means something

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Speaker 1: in the universe. It like describes someone which actually exists

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Speaker 1: or is important. And so he connected entropy not just

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Speaker 1: to heat, but also to temperature. Right. Temperature also something

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Speaker 1: people were trying to understand. And so we're going to

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Speaker 1: get into the mathematics of what that all means and

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Speaker 1: how it works a little later on. But Colossius's other

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Speaker 1: big contribution was the word. He created the word entropy.

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Speaker 1: Before this, we had heat and we had temperature. But

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Speaker 1: Colossius created the word entropy to think about energy flow.

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Speaker 2: And so at this point he's thinking about the movements

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Speaker 2: of heat or the movement of energy. But like so

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Speaker 2: when I think of entropy, I usually think of like

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Speaker 2: stuff getting lost. Was the idea of stuff getting lost

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Speaker 2: or getting disordered part of this idea or is he

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Speaker 2: just tracking the flow of things not disordered?

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Speaker 1: Disorder comes later with Boltzmann. We'll get to there in

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Speaker 1: a minute. But he's thinking about the energy flow and

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Speaker 1: where does it go, and he's using that to understand

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Speaker 1: why engines will wind down, right for sure, because entropy

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Speaker 1: is one of the reasons energy doesn't flow completely perfectly.

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Speaker 1: But I also love the story of how he came

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Speaker 1: up with the word. So entropy is like a word

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Speaker 1: he invented. He took the letters E N from energy

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Speaker 1: because it's related to energy, and then he took the

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Speaker 1: word trophy from the Greek word for change. So he's like, oh,

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Speaker 1: this is cool entropy. And you know, he was cognizant

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Speaker 1: of the fact that this is something he was inventing,

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Speaker 1: and it was kind of a recent idea. So that's

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Speaker 1: why he reached all the way back to Greek, because

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Speaker 1: he wanted it to connect it with like ancient languages

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Speaker 1: and ancient thoughts, and he said, quote, I prefer going

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Speaker 1: to the ancient languages for the names of important scientific quantities,

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Speaker 1: so that they may mean the same thing in all

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Speaker 1: living tongues. I think he was hoping that, like, if

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Speaker 1: he uses a Greek root, then even like Romanians and

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Speaker 1: Bulgarians and English speakers and everybody is going to have

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Speaker 1: some understanding intuitively of what this concept means.

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Speaker 2: Now I am imagining him saying that in a toga.

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Speaker 1: He's carving it into marble.

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Speaker 2: Right, and has history judged this to have been a

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Speaker 2: good decision.

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Speaker 1: I don't know. I mean, listen to the listeners, Like,

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Speaker 1: entropy is very confusing. I don't think anybody has the

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Speaker 1: same idea of what entropy is. And there's famous physicists

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Speaker 1: a few decades ago, Leon Cooper, who won the Nobel

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Speaker 1: Prize for superconductivity. So like a dude knows his stuff

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Speaker 1: and he says the COLOSSI has quote succeeded in coining

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Speaker 1: a word that means the same thing to everybody. Nothing.

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Speaker 1: I don't know. If I invent something so pervasive that

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Speaker 1: people are griping about it, then like, hey, you know

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Speaker 1: I've done something. All publicity is good publicity, right, We'll.

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Speaker 2: Never be sure about that, but okay.

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Speaker 1: And so at this point we have sort of these

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Speaker 1: macroscopic handles on it. We're describing temperature and energy and

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Speaker 1: entropy as things we can measure about the stuff we experience, right,

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Speaker 1: A macroscopic that means like stuff in our world the

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Speaker 1: human scale, you know, like you can take a thermometer

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Speaker 1: and you can put it in your water. You can

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Speaker 1: measure the temperatures, the number you can measure about like

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Speaker 1: large amounts of physical things. But people again wanted to

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Speaker 1: understand these things microscopically, like what happens down below? If

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Speaker 1: you're understanding the particles, what is this all mean? And

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Speaker 1: on the show we do that a lot, and people

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Speaker 1: are often writing in to ask me, like, well, what's

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Speaker 1: really happening at the particle level during hawking radiation or

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Speaker 1: when light bounces off a mirror or something like, what's

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Speaker 1: really going on? As if like the reductionist explanation reveals

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Speaker 1: something truer, And you know, we'll talk about that in

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Speaker 1: a minute, but I want people to understand that there

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Speaker 1: are many layers of the universe of reality. None of

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Speaker 1: them are more true than the other. We have this

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Speaker 1: sense that like, as you go deeper, maybe you're approaching

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Speaker 1: some fundamental layer of explanation, but every layer is useful.

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Speaker 1: You know, the macroscopic view, the human level view of

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Speaker 1: the universe is just as valid and just as useful,

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Speaker 1: even if there is another layer underneath. Because the amazing

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Speaker 1: thing is that you can write equations that work to

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Speaker 1: describe the macroscopic without understanding the microscopic. The universe gives

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Speaker 1: us that that access to many different layers of reality.

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Speaker 2: So if every layer is useful, what I'm hearing you

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Speaker 2: say is that it's okay that I skip chemistry. I

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Speaker 2: can focus on the other useful layers. We tell me

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Speaker 2: just as much.

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Speaker 1: I'm saying, and unfortunately you can quote me on this.

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Speaker 1: Chemistry has its uses. There are places where there are

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Speaker 1: problems you can't solve using biology or we're using physics.

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Speaker 1: You need that intermediate step where you're like, you're thinking

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Speaker 1: about the stoichiometry and whatever. So you're like, yes, chemist's

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Speaker 1: out there. I appreciate you. It's not that chemistry is terrible,

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Speaker 1: it's just that I can't do it.

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Speaker 2: Same same Yep, No, I appreciate you too, all right.

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Speaker 1: So then late eighteen hundreds we have Boltzmann. He's one

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Speaker 1: of the guys that founded statistical mechanics and thinking about

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Speaker 1: things in terms of the particles. You really want to understand,

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Speaker 1: like what is temperature in terms of the particles, Like

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Speaker 1: if I have something hot and something cold, what's going

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Speaker 1: on microscopically? And he made this huge contribution connecting temperature

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Speaker 1: to microscopic motion and specifically defining entropy in terms of

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Speaker 1: what's going on microscopically. This is a huge leap forward

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Speaker 1: and really one of the only places in physics or

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Speaker 1: maybe even in science where we have a mathematical bridge

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Speaker 1: between two different layers of reality, where you can take

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Speaker 1: the microscopic understanding of like particles whizzing around and use

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Speaker 1: it to derive the macroscopic rules right different levels of reality.

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Speaker 1: Is like when you have different kinds of laws, Like

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Speaker 1: particles have different behavior than liquid flowing, but we know

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Speaker 1: liquids are made of particles, and so liquids are this

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Speaker 1: thing that emerge from particles, and usually we don't know

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Speaker 1: how to derive it. We can like find the laws

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Speaker 1: for liquids and find the laws for particles, but we

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Speaker 1: don't know how to connect them, right, Like you can't

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Speaker 1: derive fluid mechanics from the standard model. But here he

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Speaker 1: developed an understanding of what's going on for particles and

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Speaker 1: he built the mathematical bridge, like you can derive the

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Speaker 1: ideal gas law from Boltzmann's description of what's happening with

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Speaker 1: these particles. It's amazing. It's like the only place I've

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Speaker 1: ever seen this kind of connection where like, not only

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Speaker 1: do you have a reductionist ability to see the lower level.

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Speaker 1: But also there's like a mathematical bridge that shows you

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Speaker 1: why it works. It's kind of incredible.

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Speaker 2: Why is that so rare?

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Speaker 1: Because the universe is complicated, you know, like to go

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Speaker 1: from micros gopic to macroscopic, you have to describe a

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Speaker 1: lot of stuff, and usually they're two hurdles chaos and approximations.

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Speaker 1: Chaos because like, sometimes the tiny little details matter, you know,

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Speaker 1: like butterfly flaps its wings in China, hurricane goes a

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Speaker 1: different direction, like, so you can't ignore those little details,

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Speaker 1: which means you have to keep track of lots and

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Speaker 1: lots and lots of little details, like remember how many

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Speaker 1: atoms there are in a drop of water, right, like

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Speaker 1: Avagajo's number is a big, big number. Calculating all those

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Speaker 1: details is essentially impossible, so you end up making approximations.

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Speaker 1: And sometimes those approximations work, like Boltzmann's big contribution was

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Speaker 1: finding ways to calculate these averages that work mostly, but

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Speaker 1: sometimes they don't, and maybe we just don't have the

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Speaker 1: right kind of math. So in principles should be possible,

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Speaker 1: but the approximations we make along the way and the

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Speaker 1: sensitivity to the little details make it really, really hard.

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Speaker 1: That's why we need chemistry.

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Speaker 2: All right, Well, on that note, let's take a break

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Speaker 2: so that we can sort of absorb the fact that

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Speaker 2: we need chemistry and in terms with that, and when

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Speaker 2: we get back we'll talk about the different actual definitions

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Speaker 2: of entropy. All Right, we're back. We've all come to

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Speaker 2: terms with the fact that we need chemistry in our life.

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Speaker 2: And I have a confession to make. I actually minored

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Speaker 2: in chemistry and my birthday is October twenty third, which

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Speaker 2: is ten twenty three Avagadro's number ten to the twenty third.

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Speaker 2: So when I was in college, all of my parties

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Speaker 2: were chemistry themed parties. We would play like periodic table games.

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Speaker 2: I know this confession time.

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Speaker 1: Haring this on me. Now we've been working together for

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Speaker 1: so long.

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Speaker 2: I felt like I had to tell you I can't

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Speaker 2: live this lie anymore.

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Speaker 1: Daniel, was this burning a hole in your psyche all

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Speaker 1: these times?

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Speaker 2: But I cannot tell you how large my bill was

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Speaker 2: at the glassware depot because I they broke so much

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Speaker 2: glass in my chemistry journey. I decided there's no way

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Speaker 2: I can make a living out of this. I can

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Speaker 2: maybe just become bankrupt. But anyway, Okay, let's get back

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Speaker 2: to entropy. We've talked about how you can study heat

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Speaker 2: to do work and how that heat sort of moves around.

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Speaker 2: Tell me about the relationship between those phenomena with entropy.

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Speaker 1: Yeah, So what we end up with is a description

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Speaker 1: of entropy from several different perspectives. We have like Carno

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Speaker 1: and Classius. Their description of entropy is like something the

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Speaker 1: same level is like temperature and energy a macroscopic quantity, right,

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Speaker 1: a thermodynamic quantity that relates to like temperature and energy flow.

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Speaker 1: And then we have Boltzman. He describes entropy statistically in

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Speaker 1: terms of like the little particles and how you average

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Speaker 1: those up and how that emerges from those tiny details.

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Speaker 1: Later on, a guy named Shannon creates an idea of

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Speaker 1: information entropy, which is probably what people were talking about

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Speaker 1: when they connect jazz to entropy. So we have three

437
00:21:59,200 --> 00:22:01,800
Speaker 1: different definition of entropy, and they're actually more. There's like

438
00:22:01,880 --> 00:22:05,679
Speaker 1: five different definitions of entropy and they're all related. And

439
00:22:05,760 --> 00:22:09,000
Speaker 1: we'll talk about the statistical and the thermodynamic definitions of

440
00:22:09,119 --> 00:22:12,200
Speaker 1: entropy today, but they're connected. They're not the same thing,

441
00:22:12,280 --> 00:22:14,760
Speaker 1: but they are similar and you might think, like, what

442
00:22:15,280 --> 00:22:18,040
Speaker 1: are you talking about. How can you have different definitions

443
00:22:18,080 --> 00:22:21,239
Speaker 1: of the same thing, Right, Well, we already have that,

444
00:22:21,400 --> 00:22:24,960
Speaker 1: Like for temperature temperature, we have a statistical view of temperature.

445
00:22:25,040 --> 00:22:27,800
Speaker 1: We may have a thermodynamic view of temperature. These things

446
00:22:27,800 --> 00:22:30,159
Speaker 1: are a little bit fuzzy, and just like we have

447
00:22:30,240 --> 00:22:33,240
Speaker 1: different levels of understanding of the universe, some of which

448
00:22:33,240 --> 00:22:35,920
Speaker 1: are useful sometimes and not others. Like particle physics great

449
00:22:35,920 --> 00:22:38,760
Speaker 1: when you're at the LEDC, not so useful when you're

450
00:22:38,800 --> 00:22:42,240
Speaker 1: pouring liquid into beakers. Right, they're useful in some cases

451
00:22:42,240 --> 00:22:44,720
Speaker 1: and not useful in others. Because we don't have a

452
00:22:44,800 --> 00:22:48,680
Speaker 1: complete understanding of the universe. We have these approximate, limited

453
00:22:48,800 --> 00:22:51,640
Speaker 1: views into the universe, and you've got to pick which

454
00:22:51,680 --> 00:22:54,520
Speaker 1: toolkit you use. So that's why we end up with

455
00:22:54,600 --> 00:22:57,480
Speaker 1: several different definitions of entropy. But you know they are connected,

456
00:22:57,480 --> 00:23:00,000
Speaker 1: and today we're going to show you some of those connections.

457
00:23:00,080 --> 00:23:02,960
Speaker 2: Biologist, I'm thinking about the definition of species of the

458
00:23:03,000 --> 00:23:05,480
Speaker 2: word species, right, same sort of situation. We'll have a

459
00:23:05,480 --> 00:23:06,760
Speaker 2: whole episode on that at some point.

460
00:23:07,800 --> 00:23:09,280
Speaker 1: Please. That sounds fascinating.

461
00:23:10,080 --> 00:23:12,240
Speaker 2: Yeah, we could drink and discuss this for like weeks

462
00:23:12,280 --> 00:23:14,520
Speaker 2: on end If we have enough biologists together that and

463
00:23:14,520 --> 00:23:15,920
Speaker 2: somehow we'll start talking about boop.

464
00:23:15,960 --> 00:23:18,520
Speaker 1: But anyway, also, and then I get to have fake

465
00:23:18,560 --> 00:23:20,560
Speaker 1: outrage and how ridiculous you guys are.

466
00:23:22,560 --> 00:23:25,719
Speaker 2: That's fair, that's fair taste in my own medicine. All right,

467
00:23:25,760 --> 00:23:27,480
Speaker 2: let's start with the statistical definition.

468
00:23:27,760 --> 00:23:30,440
Speaker 1: Okay, So statistical definition is a good entry point because

469
00:23:30,480 --> 00:23:32,600
Speaker 1: I think it connects to a lot of people's intuitive

470
00:23:32,640 --> 00:23:37,440
Speaker 1: description of entropy as related to chaos or disorder or something.

471
00:23:37,760 --> 00:23:40,359
Speaker 1: And you often hear people say entropy is a measure

472
00:23:40,359 --> 00:23:43,520
Speaker 1: of disorder in the universe. But that's missing a lot

473
00:23:43,520 --> 00:23:46,800
Speaker 1: of really important nuance that I really want people to

474
00:23:46,960 --> 00:23:50,280
Speaker 1: grab hold of. Entropy does have to do with order,

475
00:23:50,520 --> 00:23:53,920
Speaker 1: but specifically, it's a relative quantity. It's not an absolute

476
00:23:53,960 --> 00:23:55,879
Speaker 1: thing where you're like, you measure the disorder and you

477
00:23:55,920 --> 00:23:58,040
Speaker 1: get a number. It has to do with how much

478
00:23:58,080 --> 00:24:02,000
Speaker 1: information you have about two relative levels of the universe,

479
00:24:02,560 --> 00:24:04,639
Speaker 1: and it requires you to define those two levels. So

480
00:24:04,640 --> 00:24:07,720
Speaker 1: we have like a macroscopic view, things you can observe

481
00:24:08,000 --> 00:24:12,080
Speaker 1: like temperature or energy or density or something that you

482
00:24:12,119 --> 00:24:14,680
Speaker 1: can measure sort of at the human level, and then

483
00:24:15,000 --> 00:24:18,600
Speaker 1: micro states things that you can't observe arrangements of the

484
00:24:18,600 --> 00:24:21,840
Speaker 1: particles or something inobservable that would give you that same

485
00:24:22,000 --> 00:24:25,680
Speaker 1: macro state. So you have to pick these two levels, right,

486
00:24:25,840 --> 00:24:29,560
Speaker 1: macro and micro in order to even define entropy. Entropy

487
00:24:29,920 --> 00:24:32,560
Speaker 1: has to do with how many different micro states you

488
00:24:32,600 --> 00:24:35,840
Speaker 1: can have that are consistent with the same macro state

489
00:24:35,880 --> 00:24:36,640
Speaker 1: that you measure.

490
00:24:36,840 --> 00:24:38,720
Speaker 2: I would love an example.

491
00:24:38,600 --> 00:24:41,719
Speaker 1: All right, So let's do an example. Let's say, for example,

492
00:24:41,760 --> 00:24:44,240
Speaker 1: you have ten coins and you flip them. They're either

493
00:24:44,280 --> 00:24:47,960
Speaker 1: heads or tails. Okay, and let's say that macroscopically, because

494
00:24:47,960 --> 00:24:50,120
Speaker 1: you have limited information about the universe, all you can

495
00:24:50,200 --> 00:24:52,680
Speaker 1: know is how many heads there are. You can't tell

496
00:24:52,760 --> 00:24:55,199
Speaker 1: which coin is heads and which coin is tails. You

497
00:24:55,240 --> 00:24:57,240
Speaker 1: can just know how many heads there are, So maybe

498
00:24:57,240 --> 00:25:01,240
Speaker 1: this five, maybe this ten. Macroscopically, you always have limited information,

499
00:25:01,680 --> 00:25:04,440
Speaker 1: like when you measure the temperature of your coffee. You're

500
00:25:04,480 --> 00:25:06,720
Speaker 1: not measuring the speed of every individual particle. You have

501
00:25:06,800 --> 00:25:11,520
Speaker 1: some big overall average quantity, right, So that's your macroscopic information,

502
00:25:12,160 --> 00:25:15,000
Speaker 1: and then we'll define the microscopic is like, actually, which

503
00:25:15,040 --> 00:25:18,520
Speaker 1: coins are heads? Right? So you know microscopically, like maybe

504
00:25:18,560 --> 00:25:20,520
Speaker 1: it's the first five or heads and the second fiber

505
00:25:20,560 --> 00:25:24,840
Speaker 1: tails or whatever. Okay, so we've defined a macro state

506
00:25:25,040 --> 00:25:27,719
Speaker 1: and a micro state. An entropy is a measure of

507
00:25:27,760 --> 00:25:30,399
Speaker 1: how many micro states you can have for a given

508
00:25:30,480 --> 00:25:34,000
Speaker 1: macro state. So say, for example, my macro state, which

509
00:25:34,040 --> 00:25:36,159
Speaker 1: is just how many heads there are? I flip all

510
00:25:36,160 --> 00:25:39,800
Speaker 1: the coins and I tell you there are zero heads. Well,

511
00:25:39,960 --> 00:25:42,760
Speaker 1: how many micro states are there they can give you

512
00:25:42,840 --> 00:25:45,280
Speaker 1: zero heads? How many arrangements of those coins can give

513
00:25:45,280 --> 00:25:51,080
Speaker 1: you zero heads one? They all yeah, exactly. So that's

514
00:25:51,080 --> 00:25:53,840
Speaker 1: a very small number of micro states. What if I

515
00:25:53,840 --> 00:25:55,880
Speaker 1: do it again, and this time I can tell you, well,

516
00:25:55,960 --> 00:25:58,719
Speaker 1: the macro state is that one of the coin has heads.

517
00:25:58,920 --> 00:26:02,400
Speaker 1: How many microstate are there that can give you one

518
00:26:02,480 --> 00:26:06,159
Speaker 1: coin having heads? Ten exactly? Ten? Choose one for the

519
00:26:06,200 --> 00:26:08,480
Speaker 1: mathematicians out there. Now, if I say, okay, we do

520
00:26:08,520 --> 00:26:10,800
Speaker 1: it again, and this time we got five heads, how

521
00:26:10,840 --> 00:26:12,080
Speaker 1: many micro states are there?

522
00:26:13,080 --> 00:26:16,480
Speaker 2: I'm gonna give you the middle finger because I can't

523
00:26:16,520 --> 00:26:17,640
Speaker 2: calculate that on air.

524
00:26:18,480 --> 00:26:20,720
Speaker 1: It's a big number, right, It's like ten times nine

525
00:26:20,800 --> 00:26:23,560
Speaker 1: times eight whatever. It's a big number. So the point

526
00:26:23,600 --> 00:26:26,560
Speaker 1: is each macro state has a different number of micro states.

527
00:26:27,000 --> 00:26:29,400
Speaker 1: Some of them have only one arrangement of the coins

528
00:26:29,600 --> 00:26:33,199
Speaker 1: that will give you the same macro state, that's low entropy.

529
00:26:33,440 --> 00:26:36,560
Speaker 1: If you have few micro states that are consistent with

530
00:26:36,640 --> 00:26:38,560
Speaker 1: that macro state, it's low entropy. If you have a

531
00:26:38,640 --> 00:26:41,160
Speaker 1: lot of micro states that are consistent with your macro state,

532
00:26:41,240 --> 00:26:43,520
Speaker 1: like if your macro state is five heads, then there's

533
00:26:43,560 --> 00:26:47,200
Speaker 1: lots of different arrangements of that, that's high entropy. Okay,

534
00:26:47,240 --> 00:26:49,600
Speaker 1: So the key here it's not just disorder like how

535
00:26:49,640 --> 00:26:53,119
Speaker 1: scrambled are the heads and tails. It's relative lack of

536
00:26:53,240 --> 00:26:55,920
Speaker 1: knowledge between the micro state and the macro state.

537
00:26:56,680 --> 00:26:57,879
Speaker 2: Okay, I get that.

538
00:26:58,240 --> 00:26:59,720
Speaker 1: If you hold onto that in your head, it actually

539
00:26:59,720 --> 00:27:03,240
Speaker 1: makes it very easy to understand why entropy tends to

540
00:27:03,280 --> 00:27:06,119
Speaker 1: increase in the universe. You just need one more piece

541
00:27:06,160 --> 00:27:09,760
Speaker 1: of information. If you assume that all the micro states

542
00:27:09,800 --> 00:27:13,720
Speaker 1: are equally likely, like any particular arrangement is equally likely,

543
00:27:13,880 --> 00:27:16,000
Speaker 1: And that's true in this example of the coins, because

544
00:27:16,080 --> 00:27:18,800
Speaker 1: like you know, every coin toss is independent. You're just

545
00:27:18,840 --> 00:27:21,639
Speaker 1: as likely to get all heads as all tails or

546
00:27:21,680 --> 00:27:25,400
Speaker 1: any other particular arrangement like heads tails, heads tails heads tails,

547
00:27:25,400 --> 00:27:29,160
Speaker 1: fine specifying them exactly, every micro state is equally likely.

548
00:27:29,720 --> 00:27:31,600
Speaker 1: What does that mean? Well, if you just slip all

549
00:27:31,600 --> 00:27:35,200
Speaker 1: the coins, you're more likely to get a macro state

550
00:27:35,240 --> 00:27:39,439
Speaker 1: that has high entropy, because the macro states that have

551
00:27:39,520 --> 00:27:42,760
Speaker 1: low entropy by definitions are the ones with few micro states,

552
00:27:42,800 --> 00:27:45,680
Speaker 1: Like it's hard to get all heads or hard to

553
00:27:45,720 --> 00:27:47,919
Speaker 1: get all tails. There's lots and lots of ways to

554
00:27:47,960 --> 00:27:50,760
Speaker 1: get five heads and fives tails. So if you keep

555
00:27:50,800 --> 00:27:54,600
Speaker 1: flipping coins right, then on average, you're going to get

556
00:27:54,720 --> 00:27:58,920
Speaker 1: higher entropy than lower entropy. And so the universe does

557
00:27:58,960 --> 00:28:03,120
Speaker 1: this not with coin but with quantum states. If each

558
00:28:03,240 --> 00:28:06,560
Speaker 1: quantum state of the universe is equally likely, then the

559
00:28:06,640 --> 00:28:11,200
Speaker 1: universe tends towards higher entropy because as you keep flipping coins,

560
00:28:11,240 --> 00:28:15,000
Speaker 1: you're more likely to get microscopic configurations that give you

561
00:28:15,119 --> 00:28:17,520
Speaker 1: higher entropy, just because there are more of them.

562
00:28:17,720 --> 00:28:20,160
Speaker 2: So so far, I haven't heard anything that would suggest

563
00:28:20,720 --> 00:28:23,880
Speaker 2: that that makes the universe more disordered or anything like that.

564
00:28:24,080 --> 00:28:24,960
Speaker 2: And is that right?

565
00:28:25,320 --> 00:28:27,720
Speaker 1: So here we get a little slippery because we have

566
00:28:27,800 --> 00:28:31,480
Speaker 1: a nice crisp mathematical definition of micro states and macro

567
00:28:31,520 --> 00:28:35,560
Speaker 1: states and numbers, and entropy is mathematically the log of

568
00:28:35,600 --> 00:28:38,080
Speaker 1: the number of micro states. So what do we mean

569
00:28:38,120 --> 00:28:40,760
Speaker 1: by disorder? Disorder is like one of these intuitive words

570
00:28:40,760 --> 00:28:42,600
Speaker 1: that we use that we don't have a crisp definition

571
00:28:42,640 --> 00:28:44,640
Speaker 1: of but we can try to connect it, you know.

572
00:28:44,800 --> 00:28:48,080
Speaker 1: So for example, if I told you all the coins

573
00:28:48,080 --> 00:28:50,120
Speaker 1: are the same, you'd be like, oh, that's nice and ordered.

574
00:28:50,320 --> 00:28:52,880
Speaker 1: If I told you, oh, it's a scrambled headstaales tails

575
00:28:52,880 --> 00:28:56,160
Speaker 1: has whatever, that would seem more disordered, right, And so

576
00:28:56,280 --> 00:28:59,480
Speaker 1: in that sense it connects with that intuitive definition. But

577
00:28:59,480 --> 00:29:02,120
Speaker 1: I think there are other examples that are maybe more intuitive.

578
00:29:02,360 --> 00:29:05,880
Speaker 2: When I hear disorder, my connotation of disorder is that

579
00:29:05,960 --> 00:29:09,160
Speaker 2: it's something bad is happening, or like we're moving towards

580
00:29:09,200 --> 00:29:12,840
Speaker 2: a state of more badness. But what we're really saying

581
00:29:13,080 --> 00:29:19,320
Speaker 2: is that as entropy increases at like each individual point

582
00:29:19,560 --> 00:29:23,400
Speaker 2: of interest, it's just harder to predict what's happening at

583
00:29:23,440 --> 00:29:25,600
Speaker 2: each of those spots.

584
00:29:25,840 --> 00:29:28,360
Speaker 1: Yeah, I don't think you need to connect disorder with badness,

585
00:29:28,400 --> 00:29:30,120
Speaker 1: you know, to think that maybe the universe is just

586
00:29:30,160 --> 00:29:32,400
Speaker 1: getting jazzier as time goes on.

587
00:29:33,080 --> 00:29:35,080
Speaker 2: That sounds good, That sounds good depending on my mood.

588
00:29:35,840 --> 00:29:38,320
Speaker 1: You know, we're getting rid of the melody, we're kicking

589
00:29:38,360 --> 00:29:41,280
Speaker 1: out inchin ideas about keys and whatever, and we're just

590
00:29:41,320 --> 00:29:44,400
Speaker 1: wandering up and down the scale without a plan. The

591
00:29:44,520 --> 00:29:46,120
Speaker 1: universe is just getting jazzier.

592
00:29:46,520 --> 00:29:50,880
Speaker 2: Is it less planned or is it just you don't

593
00:29:51,440 --> 00:29:54,400
Speaker 2: have as good a handle at the microscale of what's

594
00:29:54,440 --> 00:29:58,800
Speaker 2: going on, Like, does that necessarily result in something less planned?

595
00:29:59,440 --> 00:30:03,160
Speaker 2: I guess you would say that zero heads is a

596
00:30:03,200 --> 00:30:07,440
Speaker 2: more planny state to be in than five heads. Is

597
00:30:07,440 --> 00:30:08,160
Speaker 2: that what we're saying.

598
00:30:08,440 --> 00:30:10,200
Speaker 1: I have a little bit of trouble with the intuitive

599
00:30:10,240 --> 00:30:13,640
Speaker 1: concept of disorder again, because it's not very well defined.

600
00:30:14,080 --> 00:30:16,320
Speaker 1: I think it's maybe easier to think about it in

601
00:30:16,440 --> 00:30:20,120
Speaker 1: terms of where stuff is physically rather than heads and tails.

602
00:30:20,680 --> 00:30:23,920
Speaker 1: So let's take another example that's maybe more intuitive. So

603
00:30:24,000 --> 00:30:26,560
Speaker 1: let's say, for example, you have one hundred particles in

604
00:30:26,600 --> 00:30:31,120
Speaker 1: a box, and instead of just knowing like the average

605
00:30:31,440 --> 00:30:34,720
Speaker 1: energy of those particles, your macroscopic measurement can tell you

606
00:30:34,720 --> 00:30:37,440
Speaker 1: the energy distribution, So you can tell the difference between

607
00:30:37,480 --> 00:30:39,800
Speaker 1: like all the energies in one particle or the energy

608
00:30:39,840 --> 00:30:43,400
Speaker 1: is shared, okay, And so if all the energy is

609
00:30:43,440 --> 00:30:45,440
Speaker 1: in just one of those hundred particles, one of them

610
00:30:45,480 --> 00:30:47,520
Speaker 1: is like going crazy whizzing around. The other ones are

611
00:30:47,560 --> 00:30:50,320
Speaker 1: just sitting there. How many microstates are there that are

612
00:30:50,360 --> 00:30:53,080
Speaker 1: consistent with that? Well, one hundred, because there's one hundred

613
00:30:53,080 --> 00:30:55,560
Speaker 1: particles and you can't tell which particle is which, but

614
00:30:55,600 --> 00:30:57,600
Speaker 1: there's one hundred ways you could give all the energy

615
00:30:57,600 --> 00:31:00,400
Speaker 1: to just one particle. On the other hand, and if

616
00:31:00,440 --> 00:31:03,320
Speaker 1: you share the energy, right, if you're in a macro

617
00:31:03,360 --> 00:31:06,560
Speaker 1: state where the energy is smoothly shared between them, now

618
00:31:06,600 --> 00:31:08,880
Speaker 1: you have a lot of different particles that have energy,

619
00:31:09,000 --> 00:31:11,280
Speaker 1: so there's like one hundred times ninety nine times ninety

620
00:31:11,280 --> 00:31:13,280
Speaker 1: eight whatever. There's lots of different ways to arrange those

621
00:31:13,320 --> 00:31:17,000
Speaker 1: particles so that they share the energy. So you know

622
00:31:17,080 --> 00:31:20,280
Speaker 1: that seems more disordered because now you have more particles

623
00:31:20,320 --> 00:31:23,880
Speaker 1: whizzing around than rather than just one particle, and you

624
00:31:23,920 --> 00:31:27,760
Speaker 1: can make sort of similar arguments about physical locations of particles.

625
00:31:28,200 --> 00:31:30,680
Speaker 1: If your macro state is to measure the distribution of

626
00:31:30,720 --> 00:31:33,840
Speaker 1: the particles, right, then having all the particles in one

627
00:31:33,920 --> 00:31:36,400
Speaker 1: corner of the box gives you very few ways to

628
00:31:36,520 --> 00:31:39,200
Speaker 1: arrange the particles, whereas having the particles all the way

629
00:31:39,200 --> 00:31:41,360
Speaker 1: through the box, there's lots of different ways to arrange

630
00:31:41,400 --> 00:31:45,640
Speaker 1: those particles. And so the reason that happens is that

631
00:31:45,720 --> 00:31:48,640
Speaker 1: those have higher entropy, or another way to say that

632
00:31:48,760 --> 00:31:50,840
Speaker 1: is that there are just more ways for that to

633
00:31:50,880 --> 00:31:52,920
Speaker 1: happen in the universe. So if all the micro states

634
00:31:52,960 --> 00:31:56,440
Speaker 1: are equally likely, the ones with more entropy are more likely.

635
00:31:56,840 --> 00:31:59,840
Speaker 1: And in that sense, entropy is connected to disorder because

636
00:31:59,840 --> 00:32:03,600
Speaker 1: it tends to share energy, spread energy out and also

637
00:32:03,640 --> 00:32:06,560
Speaker 1: spread particles out, so it tends to make things smooth

638
00:32:06,600 --> 00:32:09,560
Speaker 1: and even rather than like clumped and tight together.

639
00:32:09,920 --> 00:32:13,000
Speaker 2: All right, now, I'm with you. That definition landed better

640
00:32:13,120 --> 00:32:14,760
Speaker 2: for me, I think or that example.

641
00:32:14,880 --> 00:32:18,080
Speaker 1: All right, cool, yeah, but it's important to understand that

642
00:32:18,120 --> 00:32:21,400
Speaker 1: the statistical definition of entropy really requires you to define

643
00:32:21,440 --> 00:32:24,280
Speaker 1: these two levels, and so there is no absolute sense

644
00:32:24,280 --> 00:32:26,120
Speaker 1: of entropy. Like you and I could look at the

645
00:32:26,120 --> 00:32:29,000
Speaker 1: same system and have different numbers for entropy. If you

646
00:32:29,040 --> 00:32:31,240
Speaker 1: have a different macro state, if you can observe more

647
00:32:31,280 --> 00:32:34,160
Speaker 1: fine grain details than I can, we have different macro states.

648
00:32:34,440 --> 00:32:37,680
Speaker 1: If we're thinking about different micro states, we have different entropies.

649
00:32:38,040 --> 00:32:41,680
Speaker 1: Entropy is a relative thing like velocity, right, So it's

650
00:32:41,720 --> 00:32:44,880
Speaker 1: not some fundamental thing in the universe from a statistical

651
00:32:44,880 --> 00:32:47,680
Speaker 1: point of view. It's this relative thing. But it's also

652
00:32:47,800 --> 00:32:52,040
Speaker 1: connected to energy and temperature and this thermodynamic sense of

653
00:32:52,280 --> 00:32:54,080
Speaker 1: entropy that CLAUSI is invented.

654
00:32:54,400 --> 00:32:57,760
Speaker 2: So could we go through this example again, but think

655
00:32:57,760 --> 00:33:02,520
Speaker 2: about how bolts then identified the macro and the micro states.

656
00:33:03,120 --> 00:33:06,400
Speaker 1: Yeah, absolutely, let's do that, and then let's think about

657
00:33:06,520 --> 00:33:08,560
Speaker 1: how that gives us a handle on energy. And it's

658
00:33:08,560 --> 00:33:12,240
Speaker 1: going to take us to understanding why energy flows and

659
00:33:12,280 --> 00:33:15,800
Speaker 1: the macroscopic sense of energy. And so let's back up

660
00:33:15,840 --> 00:33:18,200
Speaker 1: a thing about bolt men. Before we talk about entry,

661
00:33:18,240 --> 00:33:20,400
Speaker 1: Let's just talk about temperature, because temperature is this other

662
00:33:20,440 --> 00:33:23,080
Speaker 1: thing where we have like a definition of it microscopically

663
00:33:23,120 --> 00:33:26,760
Speaker 1: and macroscopically. Temperature macroscopically is like, well, you put a

664
00:33:26,800 --> 00:33:28,840
Speaker 1: thermometer in something, right, or you touch something you can

665
00:33:28,880 --> 00:33:32,040
Speaker 1: feel it's hot or it's cold. But we also amazingly

666
00:33:32,080 --> 00:33:35,840
Speaker 1: have this microscopic sense of temperature. Microscopically, we think about

667
00:33:35,880 --> 00:33:38,960
Speaker 1: just particles in their velocities. Like it gets more complicated,

668
00:33:39,000 --> 00:33:41,040
Speaker 1: you're talking about solids and liquids and whatever in different

669
00:33:41,040 --> 00:33:44,000
Speaker 1: like vibrational states. But just imagine a box of particles

670
00:33:44,000 --> 00:33:46,800
Speaker 1: and it's a simple gas and the particles are whizzing around.

671
00:33:46,880 --> 00:33:49,640
Speaker 1: What happens when something is hot is those particles have

672
00:33:49,760 --> 00:33:52,360
Speaker 1: higher speeds, and when something is cold, those particles have

673
00:33:52,480 --> 00:33:54,440
Speaker 1: lower speeds. And I think a lot of people already

674
00:33:54,440 --> 00:33:56,600
Speaker 1: have a sense of this, But what maybe you don't

675
00:33:56,600 --> 00:33:59,120
Speaker 1: appreciate is that this really is a mapping between the

676
00:33:59,160 --> 00:34:04,160
Speaker 1: microscopic and the macroscopic. You're like, hot equals high speed particles,

677
00:34:04,200 --> 00:34:08,200
Speaker 1: cold equals low speed particles. That's amazing, it's incredible that

678
00:34:08,239 --> 00:34:11,480
Speaker 1: we have this connection. Right, And those are two different

679
00:34:11,480 --> 00:34:16,400
Speaker 1: definitions of temperature definition, one statistical microscopic sense of like

680
00:34:16,480 --> 00:34:21,640
Speaker 1: particles moving, the other macroscopic thermodynamic definition of temperature where

681
00:34:21,640 --> 00:34:24,919
Speaker 1: you're like, it's hot, it's cold, right, I feel hot

682
00:34:24,960 --> 00:34:28,400
Speaker 1: and therefore heat is flowing from me. Right, This is incredible,

683
00:34:28,400 --> 00:34:30,600
Speaker 1: And this is what Boltzman did. He connected these two

684
00:34:30,640 --> 00:34:34,520
Speaker 1: senses of temperature microscopically and macroscopically.

685
00:34:35,080 --> 00:34:38,160
Speaker 2: So just to nail the point home, high temperature is

686
00:34:38,200 --> 00:34:41,040
Speaker 2: more entropy, is that right, because they're moving around and

687
00:34:41,080 --> 00:34:41,759
Speaker 2: more disordered.

688
00:34:41,960 --> 00:34:47,879
Speaker 1: Oh, no, great question. And entropy is a slightly more

689
00:34:47,920 --> 00:34:52,239
Speaker 1: subtle connection to temperature. When energy flows to erase a

690
00:34:52,280 --> 00:34:55,239
Speaker 1: temperature difference, like when something goes from hot to cold,

691
00:34:55,719 --> 00:34:58,960
Speaker 1: entropy is the stuff that's being transported. And sort of

692
00:34:58,960 --> 00:35:02,400
Speaker 1: the same way that like if you imagine an electric

693
00:35:02,520 --> 00:35:04,960
Speaker 1: circuit and you have a voltage difference, what happens when

694
00:35:05,000 --> 00:35:08,000
Speaker 1: you have a voltage difference, you have flow of current, right,

695
00:35:08,000 --> 00:35:10,719
Speaker 1: you have charges flowing from one to the other to

696
00:35:10,840 --> 00:35:15,080
Speaker 1: balance that out. Charges the stuff that's transported. When energy

697
00:35:15,120 --> 00:35:17,920
Speaker 1: flows to erase a temperature difference. You can think of it,

698
00:35:18,200 --> 00:35:20,319
Speaker 1: entropy is like the charge of that system. It's the

699
00:35:20,360 --> 00:35:24,640
Speaker 1: stuff that's being transported. And so there's this connection between

700
00:35:24,760 --> 00:35:28,680
Speaker 1: energy and heat and temperature and entropy. That's a little

701
00:35:28,719 --> 00:35:31,920
Speaker 1: bit subtle, but I think it's important to understand. So

702
00:35:32,120 --> 00:35:34,799
Speaker 1: we're familiar with the idea that energy flows, right, things

703
00:35:34,880 --> 00:35:37,719
Speaker 1: flow from hot to cold. Why does that happen? Right?

704
00:35:37,840 --> 00:35:40,600
Speaker 1: Why do things flow from hot to cold? The answer

705
00:35:41,120 --> 00:35:43,400
Speaker 1: is that when things flow from hot to cold, the

706
00:35:43,520 --> 00:35:47,239
Speaker 1: number of microstates tends to increase. Right, Just like the

707
00:35:47,280 --> 00:35:49,680
Speaker 1: example we talked about in a minute ago with the particles,

708
00:35:50,000 --> 00:35:52,320
Speaker 1: If you have one really really hot particle in ninety

709
00:35:52,400 --> 00:35:55,640
Speaker 1: nine cold ones that has less entropy than sharing the

710
00:35:55,760 --> 00:35:58,440
Speaker 1: energy among the particles, there's more ways to arrange it.

711
00:35:58,680 --> 00:36:00,320
Speaker 1: If you can give it to all the part articles,

712
00:36:00,360 --> 00:36:02,719
Speaker 1: then just give it to one. They're more micro states.

713
00:36:03,080 --> 00:36:06,200
Speaker 1: So what happens when you have a temperature difference is

714
00:36:06,320 --> 00:36:10,799
Speaker 1: even opportunity to increase the entropy. So energy moves to

715
00:36:10,840 --> 00:36:13,560
Speaker 1: maximize the micro states, not because like, oh, the universe

716
00:36:13,680 --> 00:36:16,040
Speaker 1: likes energy to be spread out or something like that.

717
00:36:16,280 --> 00:36:19,440
Speaker 1: It's because all the micro states are equally likely and

718
00:36:19,600 --> 00:36:22,680
Speaker 1: energy flows in a way that increases the number of

719
00:36:22,719 --> 00:36:27,800
Speaker 1: micro states, right. Maximizing entropy is what causes energy to flow,

720
00:36:28,280 --> 00:36:30,800
Speaker 1: or another way to say it is like energy flowing

721
00:36:31,200 --> 00:36:35,839
Speaker 1: is increasing the entropy, right, and energy stops flowing when

722
00:36:35,840 --> 00:36:39,040
Speaker 1: it no longer will increase the microstates. If you have

723
00:36:39,200 --> 00:36:41,520
Speaker 1: like two systems next to each other, A and B,

724
00:36:42,120 --> 00:36:43,880
Speaker 1: energy will flow from one to the other if it

725
00:36:43,920 --> 00:36:47,440
Speaker 1: increases the number of microstates. Right. So, now as energy

726
00:36:47,480 --> 00:36:51,000
Speaker 1: is flowing from A to B, A is losing energy,

727
00:36:51,360 --> 00:36:54,200
Speaker 1: It's going to have fewer micro states. You're losing microstates,

728
00:36:54,239 --> 00:36:56,719
Speaker 1: but B is gaining them. And this will happen as

729
00:36:56,719 --> 00:36:59,960
Speaker 1: long as the gain and B is greater than the law.

730
00:37:01,520 --> 00:37:04,480
Speaker 1: So as soon as that equalizes, as soon as moving

731
00:37:04,600 --> 00:37:06,840
Speaker 1: energy from one system to another will not increase the

732
00:37:06,920 --> 00:37:11,359
Speaker 1: total number of micro states, energy stops flowing, and that's

733
00:37:11,400 --> 00:37:15,160
Speaker 1: what we define to be temperature. Temperature is this relationship

734
00:37:15,200 --> 00:37:19,040
Speaker 1: between energy and entropy in a material. If the temperatures

735
00:37:19,040 --> 00:37:22,440
Speaker 1: are equal, there's no gain in energy flowing. It does

736
00:37:22,600 --> 00:37:27,120
Speaker 1: increase the energy. So that's the definition of temperature thermodynamically.

737
00:37:27,480 --> 00:37:31,720
Speaker 1: If the temperatures are equal, no energy flow. And mathematically

738
00:37:31,880 --> 00:37:35,399
Speaker 1: we define temperature to be this ratio of a change

739
00:37:35,440 --> 00:37:38,279
Speaker 1: in energy to a change in entropy. Chemist out there

740
00:37:38,320 --> 00:37:41,400
Speaker 1: probably know it's DEDs. So you don't have to have

741
00:37:41,480 --> 00:37:45,239
Speaker 1: an equal energy between systems. What you need is equal temperature,

742
00:37:45,360 --> 00:37:48,600
Speaker 1: which means that any energy that moves will make an

743
00:37:48,600 --> 00:37:52,120
Speaker 1: equal change in the entropy. And so when the temperature

744
00:37:52,160 --> 00:37:54,640
Speaker 1: is equal between the two objects, no heat will flow

745
00:37:54,680 --> 00:38:00,640
Speaker 1: because dedes is the same. That's the definition of temperature thermodynamically. Right,

746
00:38:00,680 --> 00:38:03,280
Speaker 1: we have the microscopic definition of temperature. It's like particles

747
00:38:03,280 --> 00:38:06,120
Speaker 1: whizzing around. It's their speed. Now we have this weird

748
00:38:06,200 --> 00:38:10,720
Speaker 1: thermodynamic definition of temperature as the ratio of energy to entropy.

749
00:38:11,160 --> 00:38:13,920
Speaker 1: It turns out you can derive one from the other. Right,

750
00:38:13,960 --> 00:38:16,880
Speaker 1: you can start with the mathematics of kinetic energy of

751
00:38:16,920 --> 00:38:20,440
Speaker 1: particles and derive this definition. That's what Boltimant did. It's

752
00:38:20,520 --> 00:38:24,520
Speaker 1: incredible mathematical bridge of temperature from one to the other

753
00:38:24,760 --> 00:38:28,600
Speaker 1: and also helps us understand entropy from one to the other.

754
00:38:29,320 --> 00:38:32,200
Speaker 1: And so that's sort of the thermodynamic sense of entropy,

755
00:38:32,480 --> 00:38:35,240
Speaker 1: and I think it's amazing because it tells us why

756
00:38:35,440 --> 00:38:39,480
Speaker 1: energy flows. Energy flows to increase the number of microstates,

757
00:38:39,480 --> 00:38:42,160
Speaker 1: and it will stop flowing when the number of microstates

758
00:38:42,360 --> 00:38:43,440
Speaker 1: will not be increased.

759
00:38:43,760 --> 00:38:47,200
Speaker 2: Okay, I exactly kept up with that explanation. So my

760
00:38:47,280 --> 00:38:50,480
Speaker 2: brain has no questions yet. So let's take a break

761
00:38:51,640 --> 00:38:54,279
Speaker 2: and when we get back, we'll see what Kelly's brain

762
00:38:54,320 --> 00:39:13,839
Speaker 2: has to offer. And we're back. So now we have

763
00:39:14,040 --> 00:39:19,680
Speaker 2: two different definitions of entropy. Let's talk about some applications

764
00:39:19,760 --> 00:39:20,879
Speaker 2: of this knowledge.

765
00:39:21,280 --> 00:39:24,759
Speaker 1: Yeah, entropy has a lot of really deep consequences, and

766
00:39:24,880 --> 00:39:28,640
Speaker 1: it touches so many topics and physics, from time to life,

767
00:39:28,640 --> 00:39:31,000
Speaker 1: to black holes, to the Big Bang to the future

768
00:39:31,120 --> 00:39:34,799
Speaker 1: of the universe. It's really incredibly pervasive. One reason is

769
00:39:34,800 --> 00:39:37,359
Speaker 1: that it's so simple. It just tells us about how

770
00:39:37,400 --> 00:39:40,640
Speaker 1: systems evolve. They evolve from less likely to more likely

771
00:39:41,160 --> 00:39:44,520
Speaker 1: and what does that mean the consequences And one of

772
00:39:44,560 --> 00:39:47,160
Speaker 1: the deepest connections with entropy is what we heard the

773
00:39:47,200 --> 00:39:50,880
Speaker 1: listeners say that somehow entropy is responsible for why time

774
00:39:51,120 --> 00:39:53,719
Speaker 1: moves forwards. And I remember hearing this for the first

775
00:39:53,719 --> 00:39:57,600
Speaker 1: time thinking, what, that's crazy, that would explain such a

776
00:39:57,640 --> 00:40:01,480
Speaker 1: deep mystery, right, Like, we have these three directions of

777
00:40:01,520 --> 00:40:03,719
Speaker 1: space and one of time, and we know space and

778
00:40:03,760 --> 00:40:07,400
Speaker 1: time are related and connected by relativity, but time is different.

779
00:40:07,880 --> 00:40:10,319
Speaker 1: You can always revisit a location in space, but you

780
00:40:10,320 --> 00:40:13,160
Speaker 1: can't revisit a location in time. And you can move

781
00:40:13,239 --> 00:40:15,720
Speaker 1: positive and negative in the X axis, but only positive

782
00:40:15,719 --> 00:40:18,440
Speaker 1: in the time axis. And why forwards are not backwards?

783
00:40:18,480 --> 00:40:20,319
Speaker 1: And like what does this all mean? So there's some

784
00:40:20,360 --> 00:40:23,040
Speaker 1: deep mysteries here about what time is.

785
00:40:23,800 --> 00:40:26,520
Speaker 2: The idea here that if entropy is increasing, you're never

786
00:40:26,560 --> 00:40:28,960
Speaker 2: going to get all the particles back in that same configuration,

787
00:40:29,080 --> 00:40:32,120
Speaker 2: and that's why you can't go back in time. Oh no,

788
00:40:32,239 --> 00:40:32,840
Speaker 2: you're laughing.

789
00:40:33,160 --> 00:40:35,200
Speaker 1: I love that. I think that is sort of a

790
00:40:35,239 --> 00:40:38,719
Speaker 1: summary of how physicists put it. The argument is a

791
00:40:38,760 --> 00:40:41,200
Speaker 1: little bit more elaborated. It's that when we look at

792
00:40:41,200 --> 00:40:45,080
Speaker 1: the laws of physics, so many of them are reversible.

793
00:40:45,160 --> 00:40:48,640
Speaker 1: They don't seem to prefer one direction. You know, for example,

794
00:40:48,960 --> 00:40:51,560
Speaker 1: in a vacuum, if you bounce a ball, it hits

795
00:40:51,600 --> 00:40:53,680
Speaker 1: the floor, comes back up, It'll come back up to

796
00:40:53,719 --> 00:40:56,919
Speaker 1: the same height, and so that path is reversible. Right.

797
00:40:57,120 --> 00:40:59,120
Speaker 1: If you play a video of that happening in a

798
00:40:59,160 --> 00:41:01,640
Speaker 1: vacuum with this new end energy loss, then you can't

799
00:41:01,640 --> 00:41:04,080
Speaker 1: tell if the video is being played backwards or forwards.

800
00:41:04,200 --> 00:41:06,600
Speaker 1: The same laws of physics supply and describe it perfectly,

801
00:41:06,800 --> 00:41:09,920
Speaker 1: same with particles, almost completely. And so people were wondering

802
00:41:09,920 --> 00:41:11,320
Speaker 1: for a long time, like, well, if the laws of

803
00:41:11,320 --> 00:41:14,279
Speaker 1: physics don't care if time goes forwards or backwards, they

804
00:41:14,320 --> 00:41:18,120
Speaker 1: work both ways, why does time go forwards? And so

805
00:41:18,640 --> 00:41:21,240
Speaker 1: entropy seems to be one of the places where physics

806
00:41:21,280 --> 00:41:24,160
Speaker 1: has a preference for one direction or the other, right,

807
00:41:24,239 --> 00:41:27,200
Speaker 1: like it likes the micro states to increase, so energy

808
00:41:27,239 --> 00:41:30,719
Speaker 1: increases with time. And then there's this leap people make.

809
00:41:30,800 --> 00:41:36,399
Speaker 1: They say, oh, energy and time increase together, therefore that's

810
00:41:36,440 --> 00:41:39,600
Speaker 1: why time moves forwards. And I'm not sure I follow

811
00:41:39,640 --> 00:41:42,520
Speaker 1: that leap of logic, Like I will accept that entropy

812
00:41:42,560 --> 00:41:46,160
Speaker 1: and time are connected. Entropy increases as time goes up.

813
00:41:46,600 --> 00:41:49,120
Speaker 1: But that same law could tell you, like, well, the

814
00:41:49,280 --> 00:41:51,920
Speaker 1: universe could still run backwards. It just wouldn't be symmetric.

815
00:41:51,960 --> 00:41:53,960
Speaker 1: It would just mean that if the universe ran backwards,

816
00:41:54,280 --> 00:41:57,760
Speaker 1: entropy would decrease. That law predicts that also, it predicts

817
00:41:57,800 --> 00:42:01,040
Speaker 1: that if time ran backwards, Andy, will, why don't we

818
00:42:01,040 --> 00:42:03,680
Speaker 1: live in that universe. I don't know it's consistent with

819
00:42:03,719 --> 00:42:06,040
Speaker 1: the second law of physics, right as long as time

820
00:42:06,120 --> 00:42:09,160
Speaker 1: runs backwards. So I don't believe that the second law

821
00:42:09,200 --> 00:42:12,600
Speaker 1: physics tells you why time runs forwards. It connects time

822
00:42:12,640 --> 00:42:15,120
Speaker 1: and entropy, but it doesn't tell you why time goes

823
00:42:15,160 --> 00:42:18,160
Speaker 1: forward or backwards. There could be folks out there living

824
00:42:18,160 --> 00:42:21,760
Speaker 1: in another universe where time runs backwards and entropy is decreasing,

825
00:42:21,800 --> 00:42:24,719
Speaker 1: and they're claiming that entropy is the reason time runs backwards.

826
00:42:25,200 --> 00:42:27,520
Speaker 1: Of course they don't call it backwards. There's definitely some

827
00:42:27,920 --> 00:42:30,919
Speaker 1: interesting hints there, but I don't believe that it conclusively

828
00:42:30,960 --> 00:42:33,320
Speaker 1: shows us why time goes forwards.

829
00:42:33,719 --> 00:42:35,360
Speaker 2: So maybe I've missed this, but I think that's the

830
00:42:35,360 --> 00:42:37,239
Speaker 2: first time we've used the phrase second law.

831
00:42:37,760 --> 00:42:40,160
Speaker 1: The second law is just a statement that entropy increases

832
00:42:40,160 --> 00:42:43,520
Speaker 1: as time goes on. Okay, delta S is greater than zero, right,

833
00:42:43,760 --> 00:42:45,920
Speaker 1: S is the symbol for entropy, and so it just

834
00:42:45,920 --> 00:42:48,160
Speaker 1: says the entropy increases as time marches on.

835
00:42:48,360 --> 00:42:50,560
Speaker 2: All right, So if I can hijack the conversation for

836
00:42:50,600 --> 00:42:53,600
Speaker 2: a second, oh please do so. You know, as someone

837
00:42:53,600 --> 00:42:56,440
Speaker 2: who spends a lot of time with evolutionary biologists. I've

838
00:42:56,440 --> 00:43:04,600
Speaker 2: been to a couple creationism evolution debates and they get spicy.

839
00:43:04,719 --> 00:43:06,520
Speaker 1: That really bends the meaning of a word debate.

840
00:43:06,560 --> 00:43:08,960
Speaker 2: Also, I felt like I learned a lot by thinking

841
00:43:09,000 --> 00:43:12,200
Speaker 2: through the arguments. But anyway, so a common point that

842
00:43:12,320 --> 00:43:15,920
Speaker 2: is brought up during these discussions is that the second

843
00:43:16,080 --> 00:43:20,040
Speaker 2: law says that things should be getting more disordered with time.

844
00:43:20,640 --> 00:43:24,640
Speaker 2: So how do you have evolution creating more complex organisms

845
00:43:24,680 --> 00:43:28,160
Speaker 2: over time? And what is the answer that you would

846
00:43:28,200 --> 00:43:30,760
Speaker 2: give them? The answer I heard, if this is helpful,

847
00:43:30,880 --> 00:43:32,680
Speaker 2: is it has to do something with the second law

848
00:43:32,760 --> 00:43:35,239
Speaker 2: being about if you're in a closed system. But the

849
00:43:35,280 --> 00:43:37,799
Speaker 2: Earth isn't a closed system because energy is coming in

850
00:43:37,800 --> 00:43:39,800
Speaker 2: from the sun, and so if you're not in a

851
00:43:39,840 --> 00:43:42,759
Speaker 2: closed system, none of that holds, Is that right?

852
00:43:43,040 --> 00:43:45,239
Speaker 1: Yeah, I'm thinking about it for a minute first, because

853
00:43:45,280 --> 00:43:48,440
Speaker 1: I'm wondering what it is meant here by complexity, you know,

854
00:43:48,600 --> 00:43:53,280
Speaker 1: like and whether it even is connected to entropy, statistically

855
00:43:53,800 --> 00:43:56,839
Speaker 1: order disorder, micro states, macro states, or if it's just

856
00:43:56,840 --> 00:44:00,359
Speaker 1: this sort of like intuitive this seems similar to that,

857
00:44:00,440 --> 00:44:02,600
Speaker 1: So let's use one word in place of the other.

858
00:44:03,640 --> 00:44:06,440
Speaker 1: I'm not even really sure that complexity is connected to entropy.

859
00:44:06,520 --> 00:44:10,040
Speaker 1: At all. But it's definitely true that life and entropy

860
00:44:10,120 --> 00:44:14,480
Speaker 1: have a close connection because living things tend to decrease

861
00:44:14,760 --> 00:44:18,480
Speaker 1: their local entropy. My body is a system that decreases

862
00:44:18,520 --> 00:44:20,960
Speaker 1: its entropy. You might wonder, like, well, if entropy is

863
00:44:21,000 --> 00:44:23,399
Speaker 1: supposed to always increase, how does that happen. Well, as

864
00:44:23,440 --> 00:44:26,240
Speaker 1: you say, I'm not isolated, right, I have a huge

865
00:44:26,360 --> 00:44:29,759
Speaker 1: environment around me, and so I exchange energy with the

866
00:44:29,800 --> 00:44:32,400
Speaker 1: environment and do all sorts of complicated stuff to locally

867
00:44:32,440 --> 00:44:36,480
Speaker 1: make my entropy go down. Overall, I'm increasing the entropy

868
00:44:36,840 --> 00:44:39,640
Speaker 1: of the environment I'm interacting with more than my entropy

869
00:44:39,680 --> 00:44:42,640
Speaker 1: is decreasing, So overall second law is fine. The point

870
00:44:42,680 --> 00:44:44,320
Speaker 1: of the second law is you can't pick out a

871
00:44:44,400 --> 00:44:46,720
Speaker 1: one part of a system and say the entropy always

872
00:44:46,760 --> 00:44:48,920
Speaker 1: has to increase for every sub part of the system.

873
00:44:48,920 --> 00:44:52,520
Speaker 1: It's just the whole system where entropy has to increase.

874
00:44:52,840 --> 00:44:55,360
Speaker 1: The same way, like you can't apply conservation of energy

875
00:44:55,560 --> 00:44:57,960
Speaker 1: to just half of a system and say, oh, the

876
00:44:58,040 --> 00:45:00,440
Speaker 1: energy is flowing out of this and so energy is

877
00:45:00,480 --> 00:45:02,640
Speaker 1: not conserved. Like energy is conserved for the whole system.

878
00:45:02,760 --> 00:45:06,319
Speaker 1: Entropy increases for the whole system. So actually, this is

879
00:45:06,360 --> 00:45:09,120
Speaker 1: one way that some physicists think we should define life.

880
00:45:09,160 --> 00:45:13,040
Speaker 1: It's like systems that decrease their local entropy at the

881
00:45:13,080 --> 00:45:17,360
Speaker 1: expense of the environment. Because you know, biologists spend hours arguing, like,

882
00:45:17,400 --> 00:45:20,040
Speaker 1: what is life anyway in the system that can reproduce

883
00:45:20,160 --> 00:45:23,840
Speaker 1: is it's something that passes on genetic information? Whatever is

884
00:45:23,880 --> 00:45:25,759
Speaker 1: all these definitions of life? And this is sort of

885
00:45:25,800 --> 00:45:29,160
Speaker 1: a physics based definition of life. It's something that decreases

886
00:45:29,160 --> 00:45:32,280
Speaker 1: its local entropy. Doesn't violate the second law of thermodynamics

887
00:45:32,320 --> 00:45:35,279
Speaker 1: to decrease your local entropy at all. And I don't

888
00:45:35,320 --> 00:45:38,440
Speaker 1: know how to think about evolution in terms of complexity.

889
00:45:38,520 --> 00:45:42,560
Speaker 1: Like I guess evolution has produced systems that tend to

890
00:45:42,600 --> 00:45:45,719
Speaker 1: decrease their local entropy more and more as time goes on.

891
00:45:46,320 --> 00:45:48,560
Speaker 1: But to me, that's not a violation of the second

892
00:45:48,600 --> 00:45:51,160
Speaker 1: law of thermodynamics at all, or really says anything about

893
00:45:51,280 --> 00:45:52,800
Speaker 1: micro versus macro states.

894
00:45:53,239 --> 00:45:55,719
Speaker 2: Interesting, That's not an answer I heard it any of

895
00:45:55,719 --> 00:45:58,799
Speaker 2: the debates that I attended. I was raised We don't

896
00:45:58,800 --> 00:46:00,440
Speaker 2: need too much of Kelly history here. And I was

897
00:46:00,520 --> 00:46:04,280
Speaker 2: raised Catholic in a family where and I know Catholicism

898
00:46:04,320 --> 00:46:06,279
Speaker 2: is okay with evolution, But I was raised in a

899
00:46:06,280 --> 00:46:09,239
Speaker 2: family where the young Earth hypothesis that Earth is only

900
00:46:09,239 --> 00:46:12,239
Speaker 2: six thousand years old was held pretty tightly, and so

901
00:46:12,320 --> 00:46:13,960
Speaker 2: I went to a lot of these debates to try

902
00:46:13,960 --> 00:46:16,200
Speaker 2: to figure out how I felt about it on my own,

903
00:46:16,320 --> 00:46:18,880
Speaker 2: and the answer I always heard from the evolutionary billogist

904
00:46:18,960 --> 00:46:21,920
Speaker 2: was well, we're not a closed system or whatever. So anyway,

905
00:46:21,960 --> 00:46:24,720
Speaker 2: that was really interesting. W what a virus be alive

906
00:46:24,800 --> 00:46:27,319
Speaker 2: according to the physicist definition of life?

907
00:46:27,920 --> 00:46:29,640
Speaker 1: That's a good question, I think it would be. I

908
00:46:29,719 --> 00:46:32,840
Speaker 1: once had a conversation with Sarah AMRII Walker, and she

909
00:46:32,920 --> 00:46:35,240
Speaker 1: wrote a fascinating book last year about this whole question.

910
00:46:35,719 --> 00:46:37,480
Speaker 1: So I should ask her that, but I think so.

911
00:46:38,040 --> 00:46:40,680
Speaker 1: But let me ask you, what was it that convinced

912
00:46:40,719 --> 00:46:43,480
Speaker 1: you that the Earth is not young, that it's billions

913
00:46:43,520 --> 00:46:45,960
Speaker 1: of years old and not thousands of years old, assuming,

914
00:46:46,000 --> 00:46:48,279
Speaker 1: of course, that you got there. I did.

915
00:46:48,440 --> 00:46:51,520
Speaker 2: I did it was? I mean, I took enough classes

916
00:46:51,680 --> 00:46:55,200
Speaker 2: where I learned about the various ways we date rocks

917
00:46:55,960 --> 00:46:59,200
Speaker 2: and about the fossil record and how complete it was,

918
00:46:59,360 --> 00:47:02,680
Speaker 2: and just sort of engaged more with what we actually

919
00:47:02,680 --> 00:47:05,239
Speaker 2: know in the science, and it became pretty clear to

920
00:47:05,280 --> 00:47:07,480
Speaker 2: me that the data was pointing to an Earth much

921
00:47:07,600 --> 00:47:10,520
Speaker 2: much much much, much, much much older than six thousand

922
00:47:10,600 --> 00:47:11,000
Speaker 2: years old.

923
00:47:11,360 --> 00:47:14,880
Speaker 1: Yeah. Wow, fascinating. So thinking about deep time and the

924
00:47:14,920 --> 00:47:17,160
Speaker 1: history of the universe in the future of the universe.

925
00:47:17,600 --> 00:47:19,920
Speaker 1: Entropy is also connected to these ideas of like the

926
00:47:19,960 --> 00:47:22,800
Speaker 1: Big Bang and the future of the universe and black holes.

927
00:47:23,480 --> 00:47:25,160
Speaker 1: And there's a lot of confusion out there about what

928
00:47:25,320 --> 00:47:28,320
Speaker 1: entropy tells us about these things. I think partially because

929
00:47:28,360 --> 00:47:31,600
Speaker 1: people are thinking about entropy from a temperature point of

930
00:47:31,640 --> 00:47:33,960
Speaker 1: view or a gravitational point of view, which are actually

931
00:47:33,960 --> 00:47:36,440
Speaker 1: a little bit different, and people are thinking about no

932
00:47:36,680 --> 00:47:39,400
Speaker 1: entropy meaning no temperature. So I thought'd be useful to

933
00:47:39,440 --> 00:47:42,160
Speaker 1: go through these a little bit and help untangle some

934
00:47:42,239 --> 00:47:42,920
Speaker 1: of the confusion.

935
00:47:43,120 --> 00:47:43,560
Speaker 2: Go for it.

936
00:47:43,600 --> 00:47:46,000
Speaker 1: So let's start the very beginning with the Big Bang. Right.

937
00:47:46,640 --> 00:47:50,240
Speaker 1: If the universe is increasing in entropy all the time,

938
00:47:50,800 --> 00:47:52,759
Speaker 1: then as you go back in time, the universe is

939
00:47:52,800 --> 00:47:55,879
Speaker 1: decreasing in entropy, and that means that entropy gets lower

940
00:47:55,880 --> 00:47:57,520
Speaker 1: and lower and lower, which means, you know, if you

941
00:47:57,560 --> 00:47:59,799
Speaker 1: go back to the very first moments that we can

942
00:47:59,800 --> 00:48:02,279
Speaker 1: think about what we call the Big Bang, when the

943
00:48:02,360 --> 00:48:05,759
Speaker 1: universe was very hot and very dense, then that must

944
00:48:05,800 --> 00:48:08,440
Speaker 1: have been very low entropy, right, because entropy is increasing,

945
00:48:08,920 --> 00:48:11,080
Speaker 1: so entry must have been very, very low. But it's

946
00:48:11,080 --> 00:48:13,480
Speaker 1: hard to get your head around. Like I'm imagining a hot,

947
00:48:13,560 --> 00:48:18,200
Speaker 1: dense gas and it's pretty smooth, right, it's not very clumpy.

948
00:48:18,680 --> 00:48:21,719
Speaker 1: That doesn't seem to me like a very low entropy situation.

949
00:48:21,840 --> 00:48:24,840
Speaker 1: In fact, it seems like I'm disorganized and everything's flying around.

950
00:48:24,840 --> 00:48:27,400
Speaker 1: How is that low entropy? This is confusing to people,

951
00:48:27,400 --> 00:48:29,479
Speaker 1: But the key thing to understand is the dominant force

952
00:48:29,560 --> 00:48:32,960
Speaker 1: there is gravity. So instead of thinking about entropy from

953
00:48:32,960 --> 00:48:35,040
Speaker 1: a point of view of like the temperature of the particles,

954
00:48:35,280 --> 00:48:37,640
Speaker 1: think about the arrangements of the particles and what's a

955
00:48:37,680 --> 00:48:39,000
Speaker 1: more likely arrangement.

956
00:48:39,400 --> 00:48:42,400
Speaker 2: So gravity is pulling everything to one spot, whereas without

957
00:48:42,440 --> 00:48:44,480
Speaker 2: that it would have been all over the place and

958
00:48:44,600 --> 00:48:47,320
Speaker 2: much more disordered and spread out. Is that the idea.

959
00:48:47,880 --> 00:48:50,759
Speaker 2: I'm going to stop trying to finish your sentences because

960
00:48:50,760 --> 00:48:54,799
Speaker 2: it reveals a little I'm understanding. But I think I'm

961
00:48:54,840 --> 00:48:55,319
Speaker 2: getting this.

962
00:48:55,760 --> 00:48:59,360
Speaker 1: A gravitational point of view, Being really spread out is

963
00:48:59,520 --> 00:49:04,759
Speaker 1: very low entropy, and being clumped together is higher entropy. Right,

964
00:49:05,000 --> 00:49:07,359
Speaker 1: Because gravity is not the same as heat, gravity tends

965
00:49:07,400 --> 00:49:10,480
Speaker 1: to clump things together instead of spread things out, and

966
00:49:10,560 --> 00:49:12,760
Speaker 1: so from a gravity point of view, being very spread

967
00:49:12,800 --> 00:49:15,400
Speaker 1: out is rare. Like if you have a bunch of

968
00:49:15,440 --> 00:49:17,799
Speaker 1: matter and you let it sit there, like, it's very

969
00:49:17,920 --> 00:49:21,480
Speaker 1: rare for it to be perfectly spread out like for

970
00:49:21,520 --> 00:49:23,880
Speaker 1: that to happen, everything would have to be in perfect balance,

971
00:49:23,960 --> 00:49:28,160
Speaker 1: like a universe that's completely smooth, where there's no perturbations.

972
00:49:28,360 --> 00:49:30,799
Speaker 1: That's what be required for gravity to not be able

973
00:49:30,840 --> 00:49:34,280
Speaker 1: to clump things together. So gravity likes to clump things together.

974
00:49:34,360 --> 00:49:38,040
Speaker 1: Clumping things together increases their entropy. From a gravitational point

975
00:49:38,040 --> 00:49:41,000
Speaker 1: of view, Remember we set entropy is relative. It's not

976
00:49:41,080 --> 00:49:43,520
Speaker 1: like there's a certain number for the universe or certain

977
00:49:43,600 --> 00:49:46,120
Speaker 1: number even for a system. It depends on the arrangements

978
00:49:46,239 --> 00:49:48,520
Speaker 1: and what you'd define as the macro and the micro states.

979
00:49:48,960 --> 00:49:51,960
Speaker 1: And so from a gravitational point of view, an initial

980
00:49:52,000 --> 00:49:54,600
Speaker 1: state where everything is very spread out is quite unlikely.

981
00:49:55,080 --> 00:49:57,080
Speaker 1: And actually one of the deep mysteries of the universe

982
00:49:57,160 --> 00:49:59,959
Speaker 1: is why did the universe begin in such a low

983
00:50:00,200 --> 00:50:02,680
Speaker 1: entropy state. If we're going from a low entropy to

984
00:50:02,760 --> 00:50:04,680
Speaker 1: high entropy and it turns out there's actually going to

985
00:50:04,719 --> 00:50:07,520
Speaker 1: be a maximum entropy of the universe, then the sort

986
00:50:07,560 --> 00:50:10,120
Speaker 1: of the time it takes to get to the maximum entropy,

987
00:50:10,200 --> 00:50:11,919
Speaker 1: which we call the heat death, which we'll talk about

988
00:50:11,960 --> 00:50:14,720
Speaker 1: in a minute, defines a sort of the interesting period

989
00:50:14,719 --> 00:50:16,600
Speaker 1: of the universe. Once we get to the heat death,

990
00:50:16,600 --> 00:50:19,799
Speaker 1: the universe isn't really very interesting anymore. So how low

991
00:50:19,840 --> 00:50:22,239
Speaker 1: the entropy is when we begin sort of defines how

992
00:50:22,320 --> 00:50:25,560
Speaker 1: long we can do interesting stuff right, and we're sort

993
00:50:25,560 --> 00:50:28,240
Speaker 1: of lucky the universe begin with very very low entropy,

994
00:50:28,360 --> 00:50:30,360
Speaker 1: Like if it started with very very high entropy, not

995
00:50:30,440 --> 00:50:32,799
Speaker 1: much would happen. I just sort of continue that way.

996
00:50:33,239 --> 00:50:36,680
Speaker 1: And so one of the mysteries of entropy actually is

997
00:50:36,719 --> 00:50:40,920
Speaker 1: like why it started with such low entropy. And as

998
00:50:41,000 --> 00:50:44,239
Speaker 1: gravity continues to do its work, it makes black holes, right,

999
00:50:44,280 --> 00:50:46,680
Speaker 1: it can clump these things together, and black holes actually

1000
00:50:46,719 --> 00:50:49,760
Speaker 1: have the maximum entropy, Like there's no way to arrange

1001
00:50:49,920 --> 00:50:53,279
Speaker 1: a mass with higher entropy than a black hole. It's

1002
00:50:53,320 --> 00:50:56,960
Speaker 1: like the maximum entropy arrangement of a system. And the

1003
00:50:57,000 --> 00:50:59,960
Speaker 1: fact that black holes have an entropy is really fascinating,

1004
00:51:00,480 --> 00:51:02,120
Speaker 1: and it was one of the ways that Hawking and

1005
00:51:02,160 --> 00:51:05,400
Speaker 1: his collaborators figured out that black holes must glow a

1006
00:51:05,400 --> 00:51:09,040
Speaker 1: little bit, because having entropy means you can define temperature

1007
00:51:09,120 --> 00:51:11,640
Speaker 1: for black holes, and if you can find temperature for

1008
00:51:11,680 --> 00:51:14,000
Speaker 1: black holes, then you can think about them glowing like

1009
00:51:14,040 --> 00:51:16,920
Speaker 1: everything else in the universe that has temperature. So you

1010
00:51:16,960 --> 00:51:21,480
Speaker 1: can derive Hawking radiation thermodynamically, saying like, well, if it

1011
00:51:21,520 --> 00:51:23,839
Speaker 1: has entropy, it's got to have some temperature and then

1012
00:51:23,840 --> 00:51:26,040
Speaker 1: it should glow in the universe. And you can think

1013
00:51:26,080 --> 00:51:28,640
Speaker 1: about the temperature of a black hole. And actually, really

1014
00:51:28,640 --> 00:51:31,319
Speaker 1: really massive black holes have lower temperature, which is why

1015
00:51:31,360 --> 00:51:34,440
Speaker 1: they glow less than small black holes that have higher

1016
00:51:34,480 --> 00:51:37,880
Speaker 1: temperature than they glow brighter. And a lot of people

1017
00:51:37,920 --> 00:51:40,920
Speaker 1: think that Hawking derived his idea of Hawking radiation from

1018
00:51:41,000 --> 00:51:43,600
Speaker 1: like thinking about the little particles near the edge of

1019
00:51:43,680 --> 00:51:46,360
Speaker 1: the black hole. But that's not true. Actually, it's not

1020
00:51:46,400 --> 00:51:49,600
Speaker 1: where the derivation comes from. It comes from thermodynamics, because

1021
00:51:49,600 --> 00:51:52,120
Speaker 1: we don't understand the gravity for little particles, like there

1022
00:51:52,200 --> 00:51:55,360
Speaker 1: is no way to think through that little example microscopically

1023
00:51:55,360 --> 00:51:57,440
Speaker 1: of what happens to the particles. We only have a

1024
00:51:57,440 --> 00:52:01,520
Speaker 1: macroscopic understanding of Hawking radiation because, as we've said many

1025
00:52:01,520 --> 00:52:04,280
Speaker 1: times on the show, we don't understand quantum gravity.

1026
00:52:05,200 --> 00:52:09,040
Speaker 2: I'm trying to decide if I can rescue my comparison

1027
00:52:09,080 --> 00:52:11,880
Speaker 2: about my house being a mess with entropy. Could I

1028
00:52:11,960 --> 00:52:14,600
Speaker 2: say my house is like a black hole because that's

1029
00:52:14,600 --> 00:52:17,440
Speaker 2: where the maximum entropy is, or I really need to

1030
00:52:17,480 --> 00:52:20,560
Speaker 2: let this comparison go. I think this is where disordered

1031
00:52:20,600 --> 00:52:22,560
Speaker 2: has a negative connotation to me, and I think that

1032
00:52:22,600 --> 00:52:24,319
Speaker 2: maybe that's been holding me back this whole time.

1033
00:52:24,400 --> 00:52:25,839
Speaker 1: I'm not going to comment because I feel like that's

1034
00:52:25,840 --> 00:52:27,200
Speaker 1: going to put me in the middle of your marriage.

1035
00:52:27,320 --> 00:52:28,440
Speaker 2: Okay, let's move on there.

1036
00:52:28,440 --> 00:52:30,440
Speaker 1: And I want Zach to like me, so all right.

1037
00:52:30,320 --> 00:52:31,399
Speaker 2: Let's move on to heat death.

1038
00:52:31,719 --> 00:52:33,480
Speaker 1: Yeah, so what's going to happen at the end of

1039
00:52:33,480 --> 00:52:37,080
Speaker 1: the universe. Well, you know, gravity clumps things together into

1040
00:52:37,120 --> 00:52:40,959
Speaker 1: black holes eventually, but those black holes also glow, right,

1041
00:52:41,360 --> 00:52:44,520
Speaker 1: and so you get the universe increasing its entropy, you

1042
00:52:44,560 --> 00:52:46,960
Speaker 1: get black holes, and those black holes glow out photons.

1043
00:52:47,239 --> 00:52:49,239
Speaker 1: And so the final end point of the universe is

1044
00:52:49,280 --> 00:52:53,200
Speaker 1: those black holes evaporate into photons and the universe just

1045
00:52:53,239 --> 00:52:56,600
Speaker 1: filled with this hawking radiation, sometimes photons, sometimes other particles,

1046
00:52:56,960 --> 00:52:59,920
Speaker 1: and that's the state of maximum entropy. So how do

1047
00:53:00,080 --> 00:53:02,520
Speaker 1: we understand the entropy in this whole story? It's low

1048
00:53:02,560 --> 00:53:05,400
Speaker 1: when the universe begins with matter mostly spread out, and

1049
00:53:05,400 --> 00:53:09,160
Speaker 1: then grows as the universe gathers together things into massive

1050
00:53:09,160 --> 00:53:12,239
Speaker 1: objects like black holes, and then keeps growing as the

1051
00:53:12,320 --> 00:53:15,520
Speaker 1: universe converts those black holes back into a bath of

1052
00:53:15,560 --> 00:53:19,120
Speaker 1: matter and radiation from black hole evaporation. How does that

1053
00:53:19,160 --> 00:53:21,880
Speaker 1: make sense in terms of our definition of entropy and

1054
00:53:21,960 --> 00:53:24,919
Speaker 1: microstates and all that. Yeah, the answer is it really

1055
00:53:24,960 --> 00:53:28,480
Speaker 1: doesn't because we don't have micro states for gravity. That

1056
00:53:28,520 --> 00:53:32,080
Speaker 1: would require understanding how gravity works for particles, and we

1057
00:53:32,239 --> 00:53:36,560
Speaker 1: just don't, not until somebody cracks quantum gravity. So this

1058
00:53:36,680 --> 00:53:40,720
Speaker 1: concept of black hole entropy is not statistical. It's thermodynamic,

1059
00:53:40,760 --> 00:53:43,720
Speaker 1: as we mentioned a minute ago. It's derived from arguments

1060
00:53:43,760 --> 00:53:47,360
Speaker 1: about temperature and about energy. We know that a black

1061
00:53:47,360 --> 00:53:50,600
Speaker 1: hole entropy grows with its surface area, and that lines

1062
00:53:50,640 --> 00:53:53,680
Speaker 1: up with our understanding that entropy grows because gravity will

1063
00:53:53,719 --> 00:53:57,040
Speaker 1: gather stuff together to make black holes larger. But then

1064
00:53:57,120 --> 00:53:59,560
Speaker 1: how does it make sense for entropy to keep growing

1065
00:53:59,600 --> 00:54:02,319
Speaker 1: as though a black holes evaporate away to something that

1066
00:54:02,440 --> 00:54:05,600
Speaker 1: resembles the early universe Again, But it turns out the

1067
00:54:05,640 --> 00:54:08,759
Speaker 1: heat death bath of radiation is not the same as

1068
00:54:08,760 --> 00:54:12,360
Speaker 1: the early universe conditions. We think that the quantum information

1069
00:54:12,680 --> 00:54:16,280
Speaker 1: is still there. The whole history of the universe is encoded,

1070
00:54:16,760 --> 00:54:19,120
Speaker 1: and so the particles that evaporated from the black holes

1071
00:54:19,120 --> 00:54:21,560
Speaker 1: are all entangled together in a complicated way. People are

1072
00:54:21,600 --> 00:54:25,440
Speaker 1: still figuring out that holds that information. So the answer

1073
00:54:25,560 --> 00:54:27,279
Speaker 1: is we still aren't sure about a lot of this

1074
00:54:27,440 --> 00:54:30,400
Speaker 1: black hole information, and entropy is a very active area

1075
00:54:30,560 --> 00:54:33,400
Speaker 1: of research. And that's the best explanation I can give.

1076
00:54:33,239 --> 00:54:35,000
Speaker 2: You, Daniel, that was a perfect explanation.

1077
00:54:35,239 --> 00:54:37,400
Speaker 1: And so we end up with this situation where energy

1078
00:54:37,680 --> 00:54:42,240
Speaker 1: is sort of surprisingly spread out again, but it's not cold.

1079
00:54:42,360 --> 00:54:45,279
Speaker 1: People confuse the heat death of the universe and think, oh,

1080
00:54:45,360 --> 00:54:48,600
Speaker 1: nothing is moving. They think of it like death freezing.

1081
00:54:48,920 --> 00:54:51,759
Speaker 1: But it's not absolute zero. It just means there's no

1082
00:54:51,840 --> 00:54:54,680
Speaker 1: way to get anything done the way like Carnot was saying,

1083
00:54:55,080 --> 00:54:57,520
Speaker 1: that you need energy differences to get stuff done. Like

1084
00:54:57,600 --> 00:55:00,200
Speaker 1: you run your temperature, you need hot and coals. The

1085
00:55:00,400 --> 00:55:02,680
Speaker 1: energy can flow from hot to cold. You need water

1086
00:55:02,760 --> 00:55:04,560
Speaker 1: to flow downhill so you can capture it with your

1087
00:55:04,560 --> 00:55:07,799
Speaker 1: water wheel. If everything is flat and smooth, then there's

1088
00:55:07,800 --> 00:55:10,799
Speaker 1: no way to do anything useful, right, And so that's

1089
00:55:10,880 --> 00:55:13,360
Speaker 1: what the heat death is. Not when everything is frozen,

1090
00:55:13,440 --> 00:55:16,359
Speaker 1: not when particles can't move, but when there's no way

1091
00:55:16,400 --> 00:55:19,160
Speaker 1: to do anything useful in the universe. And so that's

1092
00:55:19,200 --> 00:55:21,600
Speaker 1: why you can't have like life or anything else interesting

1093
00:55:21,800 --> 00:55:24,520
Speaker 1: because everything's maximumly spread out. You can't take advantage of

1094
00:55:24,560 --> 00:55:27,040
Speaker 1: any energy differences because there aren't any anymore.

1095
00:55:27,320 --> 00:55:29,680
Speaker 2: We know what temperature the heat death will be if

1096
00:55:29,680 --> 00:55:30,640
Speaker 2: it's not absolute zero.

1097
00:55:30,920 --> 00:55:32,759
Speaker 1: Yeah, it's a great question. It depends on how long

1098
00:55:32,800 --> 00:55:35,920
Speaker 1: it takes, because as the universe expands, it cools, and

1099
00:55:35,960 --> 00:55:38,799
Speaker 1: we don't know actually how quickly the universe will be

1100
00:55:38,840 --> 00:55:41,400
Speaker 1: expanding in the future. It's accelerating, but you know, the

1101
00:55:41,440 --> 00:55:44,480
Speaker 1: mechanism for that acceleration is dark energy, which is not understood.

1102
00:55:44,680 --> 00:55:46,760
Speaker 1: So unfortunately I can't give you a number for that today.

1103
00:55:46,800 --> 00:55:48,799
Speaker 2: Well. One of the things I love about our conversations

1104
00:55:48,840 --> 00:55:52,640
Speaker 2: is that so often halfway through a lesson, which is

1105
00:55:52,640 --> 00:55:55,120
Speaker 2: what some of these end up feeling like. I feel

1106
00:55:55,120 --> 00:55:57,799
Speaker 2: like I enter the conversation thinking Okay, I know what

1107
00:55:57,800 --> 00:56:00,600
Speaker 2: we're talking about, and I leave thinking, wow, that was

1108
00:56:00,719 --> 00:56:03,360
Speaker 2: a lot different than what I thought the answer was

1109
00:56:03,400 --> 00:56:06,680
Speaker 2: going to be. And so I always leave and think

1110
00:56:06,680 --> 00:56:09,360
Speaker 2: about the conversation like much longer into the day. It

1111
00:56:09,400 --> 00:56:12,040
Speaker 2: sticks with me for a while, and so thank you

1112
00:56:12,200 --> 00:56:15,480
Speaker 2: for helping me realize that I shouldn't be making entropy

1113
00:56:15,600 --> 00:56:20,200
Speaker 2: jokes about my house, and now I'll start thinking about

1114
00:56:20,280 --> 00:56:22,759
Speaker 2: jokes about how no work can get into I'm gonna

1115
00:56:22,760 --> 00:56:23,480
Speaker 2: start working on that.

1116
00:56:25,960 --> 00:56:28,680
Speaker 1: Yeah, or you know, use jazz instead. Hey, Zach, can

1117
00:56:28,719 --> 00:56:30,560
Speaker 1: you jazz up the kitchen a little bit? Or the

1118
00:56:30,640 --> 00:56:32,200
Speaker 1: kitchen has gotten a little too jazzy.

1119
00:56:32,400 --> 00:56:34,680
Speaker 2: A little too jazzy, I think is the problem with

1120
00:56:34,719 --> 00:56:37,960
Speaker 2: the kitchen. It needs more melody.

1121
00:56:38,200 --> 00:56:40,800
Speaker 1: I love thinking about these topics, and especially helping people

1122
00:56:40,880 --> 00:56:44,160
Speaker 1: understand how they really work, because so often the real

1123
00:56:44,239 --> 00:56:47,160
Speaker 1: understanding of it is more fascinating and more interesting. We're

1124
00:56:47,200 --> 00:56:49,160
Speaker 1: not throwing a wet blanket on people's idea of entropy.

1125
00:56:49,320 --> 00:56:52,719
Speaker 1: We're showing them how exciting, how jazzy it actually is.

1126
00:56:53,120 --> 00:56:54,799
Speaker 2: Yes, and I'm trying to make myself feel a little

1127
00:56:54,800 --> 00:56:57,239
Speaker 2: bit better about the multiple times in this conversation where

1128
00:56:57,280 --> 00:57:01,759
Speaker 2: I got the answer exactly opposite correct, And I guess

1129
00:57:01,840 --> 00:57:04,640
Speaker 2: I'm hoping that this is a place where people can

1130
00:57:04,640 --> 00:57:08,120
Speaker 2: come with their incorrect, preconceived notions Oh yeah, and not

1131
00:57:08,400 --> 00:57:12,759
Speaker 2: feel self conscious about having it wrong. Absolutely, because if

1132
00:57:12,840 --> 00:57:15,640
Speaker 2: Kelly can be wrong so often and can continue to

1133
00:57:15,680 --> 00:57:18,720
Speaker 2: move through her life with any degree of confidence, then

1134
00:57:18,800 --> 00:57:21,400
Speaker 2: you should also feel welcome to ask us anything, So

1135
00:57:21,520 --> 00:57:22,000
Speaker 2: reach out.

1136
00:57:22,160 --> 00:57:24,320
Speaker 1: Yeah, and if one of our explanations didn't make sense

1137
00:57:24,320 --> 00:57:26,919
Speaker 1: to you, please do reach out. It's not just Kelly

1138
00:57:27,000 --> 00:57:29,160
Speaker 1: you gets to ask questions, and not just me. You

1139
00:57:29,160 --> 00:57:31,240
Speaker 1: get to ask Kelly biology questions. We want to hear

1140
00:57:31,280 --> 00:57:33,880
Speaker 1: your questions. Please do write to us two questions at

1141
00:57:33,960 --> 00:57:36,840
Speaker 1: Daniel and Kelly dot org. We'll ride back to you.

1142
00:57:37,120 --> 00:57:39,480
Speaker 2: We respond to everybody, looking forward to hearing from you.

1143
00:57:39,640 --> 00:57:41,680
Speaker 1: All right, until then, everybody keep it chassy.

1144
00:57:49,720 --> 00:57:53,520
Speaker 2: Daniel and Kelly's Extraordinary Universe is produced by iHeartRadio. We

1145
00:57:53,560 --> 00:57:56,000
Speaker 2: would love to hear from you, We really would.

1146
00:57:56,160 --> 00:57:58,920
Speaker 1: We want to know what questions you have about this

1147
00:57:59,120 --> 00:58:01,000
Speaker 1: extraordinary I.

1148
00:58:01,000 --> 00:58:03,960
Speaker 2: Want to know your thoughts on recent shows, suggestions for

1149
00:58:04,040 --> 00:58:07,120
Speaker 2: future shows. If you contact us, we will get back

1150
00:58:07,120 --> 00:58:07,320
Speaker 2: to you.

1151
00:58:07,520 --> 00:58:11,040
Speaker 1: We really mean it. We answer every message. Email us

1152
00:58:11,080 --> 00:58:13,919
Speaker 1: at Questions at Danielankelly dot org.

1153
00:58:14,160 --> 00:58:16,280
Speaker 2: You can find us on social media. We have accounts

1154
00:58:16,360 --> 00:58:20,280
Speaker 2: on x, Instagram, Blue Sky and on all of those platforms.

1155
00:58:20,320 --> 00:58:23,280
Speaker 2: You can find us at d and kuniverse.

1156
00:58:23,400 --> 00:58:24,880
Speaker 1: Don't be shy, write to us