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Speaker 1: When and how did we learn that the Sun is

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Speaker 1: at the center of the Solar system? And if distance

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Speaker 1: and location are just relative, what does center mean? Anyway?

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Speaker 1: There's a commonly told story about all of this, how

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Speaker 1: Capernicus and Kepler over threw geocentrism with better data and

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Speaker 1: clever math, But as usual, that story is missing a

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Speaker 1: lot of the fun nuance. Did you know that it

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Speaker 1: wasn't just geocentrism versus heliocentrism, but that there was a third,

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Speaker 1: even weirder theory in the mix that also explained the

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Speaker 1: data very nicely, and that it was shockingly recently that

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Speaker 1: we were able to nail any of this down. Understanding

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Speaker 1: the true history of science is super fun because it

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Speaker 1: shows you how puzzles are actually sorted out, and how

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Speaker 1: things seem obvious in hindsight, but when you're standing at

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Speaker 1: the forefront of human knowledge, the path forward is very unclear.

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Speaker 1: Welcome to Daniel and Kelly's Extraordinary Universe.

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Speaker 2: Hello, I'm Kelly Wader Smith. I study parasites and space,

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Speaker 2: and I'm looking forward to seeing how many different incorrect

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Speaker 2: ways I can say Tycho Brahe today. That's probably one.

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Speaker 1: Hi. I'm Daniel. I study particles and aliens, And even

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Speaker 1: though I speak Danish, I'm not going to try the

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Speaker 1: correct pronunciation of tico Brahe's name.

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Speaker 2: So that wasn't it.

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Speaker 1: That was not it, because that's like a latinization of

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Speaker 1: his name, which has some other Danish formulation which I've

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Speaker 1: heard Dane say and I'm not going to try to

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Speaker 1: reproduce because it uses one of those many Danish vowels

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Speaker 1: that doesn't exist in English.

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Speaker 2: And you said, tiho.

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Speaker 1: Tico Brahe is the like Pico, the latinization of it.

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Speaker 1: But yeah, it's very different in the actual Danish.

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Speaker 2: Okay, I was closer than I think probably any of

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Speaker 2: us would have guessed. So that's pretty good.

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Speaker 1: All right, points today for kelly're right off the bat.

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Speaker 2: Whoo for not being so far off. So today we're

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Speaker 2: talking about sort of misconceptions about the way the universe works.

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Speaker 2: And so my question for you is, and I'll be honest,

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Speaker 2: mostly this is just because I want to share a

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Speaker 2: funny story. My question for you is, what is a

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Speaker 2: misconception that you have heard from a child, or a

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Speaker 2: misconception that you had as a child that you thought

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Speaker 2: was pretty funny and you'd like to share It.

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Speaker 1: Was shockingly recently that one of my children I won't

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Speaker 1: embarrass them by naming which one, revealed that they didn't

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Speaker 1: understand that stars were distant sons. What. We had a

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Speaker 1: moment at the Tenner table when I said, wait, you

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Speaker 1: know that stars are just other sons? And their jaw

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Speaker 1: just dropped like that was the moment they learned that.

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Speaker 1: And I felt like surprised and confused and embarrassed, like,

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Speaker 1: how can my child not have known this and deal

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Speaker 1: fairly recently? Oh my gosh, I have failed as a

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Speaker 1: parent and as an educator.

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Speaker 2: Wouldn't they think they were like aliens shining laser pointers?

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Speaker 1: That was my follow up question, and they were like,

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Speaker 1: you know, I just never really gave it much thought.

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Speaker 1: And I was like, what are you doing with your life?

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Speaker 1: You never thought about what the stars are? Oh my gosh,

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Speaker 1: and how have I failed you as a parent?

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Speaker 2: A plus A plus? So I mentioned to one of

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Speaker 2: my kids I also will not say which one, that

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Speaker 2: my husband's middle name is Alexander, and they go Alexander,

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Speaker 2: that's like a name for magicians. And I was like

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Speaker 2: magicians and she goes, yeah, like Alexander the Great.

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Speaker 1: Who I saw in Vegas.

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Speaker 2: He was great, it was, and I was like, Alexander

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Speaker 2: the Great was like a commander who killed a bunch

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Speaker 2: of people to make one of the largest empires in history.

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Speaker 2: He wasn't pulling rabbits out of a hat. He goes what,

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Speaker 2: oh wait, and they wishever child it was that did that?

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Speaker 2: Said what? Anyway? And then I started laughing so hard

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Speaker 2: I cried, and so that they started laughing so hard

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Speaker 2: they cried, and we both had a really good laugh

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Speaker 2: about it. And now we joke about Alexander the Great,

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Speaker 2: the Magician.

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Speaker 1: Also not the main character from Alexander and the No Good,

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Speaker 1: Very Bad, Terrible Day.

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Speaker 2: Oh I loved that book when I was a kid. Yeah,

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Speaker 2: another great one, another great Alexander, but not Alexander the Great.

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Speaker 3: Yeah.

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Speaker 1: Absolutely. And today we are trying to clear up some

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Speaker 1: of your great misconceptions about the history of physics how

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Speaker 1: we figure it it all out, because you know, physics

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Speaker 1: and science more broadly is not a linear step from

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Speaker 1: A to B. It's multiple branching paths, dead ends, and

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Speaker 1: wrong ideas which persisted for centuries before we figured stuff out.

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Speaker 1: And though we often tell the stories as a linear progression,

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Speaker 1: obviously moving from one step to the next. It's much

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Speaker 1: more interesting when you dig into the details and learn

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Speaker 1: the nuance.

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Speaker 2: And I feel like we often don't hear those stories

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Speaker 2: because they're harder to tell, but it's a much more

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Speaker 2: accurate depiction of, you know, how humans as a society work.

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Speaker 2: And so we're going to try to tell that story

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Speaker 2: today because we like challenges. And I started looking through

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Speaker 2: our outline today and I looked at the question you

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Speaker 2: sent our extraordinary yeah, And I have to think that

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Speaker 2: maybe they are wondering what's happening to the podcast that

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Speaker 2: they're listening to you, because the question you asked them is, yeah,

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Speaker 2: could the Sun or but the Earth? And maybe maybe

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Speaker 2: Kelly next week is gonna send out how many times

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Speaker 2: have you seen Bigfoot? Or how tall is Bigfoot? But

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Speaker 2: I guess we'll see what they had to say.

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Speaker 1: That's right, Right, is heliocentrism a government scam?

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Speaker 2: That's right? Are the lizard people running the world?

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Speaker 1: That's right? But there was a caveat also in the

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Speaker 1: question right. The question was is it possible that the

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Speaker 1: Sun orbits the Earth? With all the other planets orbiting

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Speaker 1: the Sun?

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Speaker 2: Oh?

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Speaker 1: Right? An even weirder idea.

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Speaker 2: Oh, you wrote that in smaller text, and so I

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Speaker 2: skipped it.

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Speaker 1: All right, So think about your mental picture of the

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Speaker 1: Solar System. Is it possible that the Sun could be

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Speaker 1: moving around the Earth with all the other planets orbiting

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Speaker 1: the Sun or is that just too weird to be true.

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Speaker 1: Here's what the extraordinaries had to say.

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Speaker 4: I don't think so, just based on what we know

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Speaker 4: about the masses of the Sun, Earth, and other planets.

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Speaker 4: I think technically the Sun and Earth orbit their common

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Speaker 4: center of mass, but I'm not sure that might still

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Speaker 4: be inside the Sun.

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Speaker 5: As I understand it, it's not that the Sun would

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Speaker 5: orbit the Earth.

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Speaker 1: It's that orbits are the two.

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Speaker 5: Objects orbiting around one point, And if you were to

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Speaker 5: expand this out to all of the planets in the

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Speaker 5: Solar System, they are all orbiting some point, which is

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Speaker 5: probably inside the Sun.

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Speaker 4: No, I do not think it is possible that the

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Speaker 4: Sun orbits the Earth with all our planets ordering the Sun.

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Speaker 4: I think we've had this figured out since Copernicus.

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Speaker 3: Now, if the Sun orbited the Earth but all the

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Speaker 3: planets still orbited it, that would make Helios really upset.

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Speaker 3: I would expect, and also be more than a three

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Speaker 3: body problem.

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Speaker 6: No, since motion is relative, you could describe the motions

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Speaker 6: of these things in such a way. But for that

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Speaker 6: to hold with all we know about gravity, the masses

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Speaker 6: of these objects, and star formation.

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Speaker 7: Is it possible that the Sun orbits Earth is other

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Speaker 7: planet's orbit in the Sun. I don't think so, because

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Speaker 7: otherwise it would mean that the Earth is the center

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Speaker 7: of gravity. And is this some orbits Earth, then all

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Speaker 7: other planets will also orbit to Earth.

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Speaker 2: All right, so at least one of our extraordinaries are

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Speaker 2: one hundred percent onto you, and provided the historical context,

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Speaker 2: I think you confuse some of them and the rest

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Speaker 2: of them are Switching over to Real Science Podcast now, Daniel.

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Speaker 1: Join us. Next week we'll be interviewing Bigfoot on his

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Speaker 1: theory of heliocentrism.

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Speaker 2: Okay, but what is the context for why you asked

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Speaker 2: this question?

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Speaker 1: In particular, the context is the history of how we

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Speaker 1: figured out the geometry of the Solar System and crucially,

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Speaker 1: how it moves in relation to the rest of the universe.

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Speaker 1: And it turns out the usual story of like the

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Speaker 1: Earth is the center of the Solar system, to this

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Speaker 1: the Sun is the center of the Solar System, and

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Speaker 1: that we moved to this new idea of that five

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Speaker 1: hundred years ago misses a lot of interesting nuance about

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Speaker 1: the history of physics and the alternative ideas which took

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Speaker 1: a long time to squash.

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Speaker 2: All right, well, let's start at the very beginning, then,

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Speaker 2: what was like the first theory for what was happening

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Speaker 2: with the Earth in the sun? I mean, fortunately, some

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Speaker 2: people who were not your kids were looking outwards and

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Speaker 2: were thinking, what's going on out there?

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Speaker 1: Out out anymore? You know, that's a blow against me

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Speaker 1: as a parent.

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Speaker 2: Ooh.

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Speaker 1: You know, if you read ancient theology and ancient writing

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Speaker 1: about the Solar system, people were curious about it for

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Speaker 1: a long long time, and they had sort of a

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Speaker 1: mental picture of how things worked. And you know, some

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Speaker 1: of them were geometric thinkers, and they imagined the Earth

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Speaker 1: as a flat disk covered in a dome and the

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Speaker 1: stars were like lights in that dome somehow, and other

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Speaker 1: theories like the Chinese or more arithmetic, just looking at

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Speaker 1: the patterns in the sky not always assembling like a

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Speaker 1: geometric picture of like where everything was at the same time.

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Speaker 1: I think the first like credible theory for how things

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Speaker 1: work comes from the ancient Greeks. You know, we're talking

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Speaker 1: like Aristotle days three hundred ish BC, which rests, of

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Speaker 1: course on the knowledge that the Earth is a sphere

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Speaker 1: and not a flat disc.

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Speaker 2: I've been reading a little bit more about the history

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Speaker 2: of like medicine and the just kind of like the

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Speaker 2: history of science. Does every piece of information we know,

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Speaker 2: like go back to Aristotle. It's just like everybody has

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Speaker 2: to have a like what did Aristotle think about this

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Speaker 2: moment in their history?

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Speaker 1: Yeah, well, you know, Aristotle and the Greeks get a

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Speaker 1: lot more credit than people usually give them because their

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Speaker 1: theory of geocentrism was honestly pretty good. Okay, Like it's

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Speaker 1: fit the data. It was the best explanation for the data.

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Speaker 1: And we're gonna explain why in a minute. And I've

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Speaker 1: often been guilty of like dismissing the Greeks as being

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Speaker 1: pre scientific about just like sitting in a cave and

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Speaker 1: thinking about the universe. But that's too simple, Like they

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Speaker 1: really did use data and look at the universe and

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Speaker 1: try to make their theories fit with their observations. And

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Speaker 1: it's like not technically empiricism because that didn't come for

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Speaker 1: a couple thousand more years, but it's almost empiricism. I mean, like,

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Speaker 1: how did they know that the Earth was a sphere

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Speaker 1: to begin with? You know, they could see that, like

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Speaker 1: the constellations were different in the northern and southern hemisphere. Right,

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Speaker 1: you see different stars, which suggests you have a different

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Speaker 1: view because you're looking out on a different part of

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Speaker 1: a round ball. Right, You're not just standing on a

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Speaker 1: disk where you would see the same view all through

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Speaker 1: the year. They could also see the shape of the

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Speaker 1: Earth when they saw lunar eclipse. Right. Remember, a lunar

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Speaker 1: eclipse is when the Earth is between the Sun and

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Speaker 1: the Moon, So the Earth is making a shadow on

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Speaker 1: the Moon instead of the Moon making a shadow on

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Speaker 1: the Earth, which means you can see the shape of

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Speaker 1: the Earth on the Moon. It's super amazing, right, It's

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Speaker 1: like the universe is revealing the shape of the Earth.

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Speaker 1: It's like if you did hand puppets, Right, you stood

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Speaker 1: up on the edge of the Earth and you stuck

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Speaker 1: your hand out during a lunar eclipse, technically you could

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Speaker 1: do like hand puppets on the surface of the moon.

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Speaker 1: The Moon is the screen there.

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Speaker 2: Right, It's amazing, But wouldn't a flat Maybe I'm not

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Speaker 2: gonna Maybe I'm not gonna want this on the record.

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Speaker 1: No, wouldn't do it.

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Speaker 2: Wouldn't a flat disc make a similar shadow as a sphere.

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Speaker 1: A flat disc would make a similar shadow if it

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Speaker 1: was perfectly aligned right. Otherwise it'd be like an ellipse,

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Speaker 1: or it would look like a line, depending on its

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Speaker 1: alignment between the Earth and the Sun. So you could,

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Speaker 1: if you only had that one piece of data, argue

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Speaker 1: that the Earth could be a flat disc that was

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Speaker 1: perfectly aligned to make a circular shadow. Yes, okay, So

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Speaker 1: that one piece of information is not enough, got.

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Speaker 2: It, okay? And then I had heard that another piece

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Speaker 2: of information that they'd use is they'd watch ships and

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Speaker 2: as the ships went away, you could see the bottom

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Speaker 2: part of the ship going away, but you'd still see

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Speaker 2: there the masts and the.

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Speaker 1: Yeah, exactly. You can literally see the curvature of the

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Speaker 1: Earth if you look over long distances, because you can

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Speaker 1: see the top of the ship and you can no

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Speaker 1: longer see the bottom of the ship. Right. And there's

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Speaker 1: also an experiment they did where you look at shadows

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Speaker 1: at different parts of the Earth, and you know, if

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Speaker 1: the sun is straight overhead in one city, so it

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Speaker 1: makes no shadow, you can measure the length of a

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Speaker 1: shadow in another city, and you can deduce whether or

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Speaker 1: not you're on a flat surface or on a curve

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Speaker 1: based on the length of that shadow. And flat earthers

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Speaker 1: also argue like, oh, but that would also be true

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Speaker 1: if the sun was not super far away. If it

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Speaker 1: was close, it could cause the same effect. But you

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Speaker 1: can roll that out by just adding a couple more

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Speaker 1: sticks and measuring more shadows. So anyway, the Earth is

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Speaker 1: not flat, and the Greeks knew that, right, and that

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Speaker 1: raised an obvious question to them, which is like, Okay,

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Speaker 1: if the Earth is a sphere, why don't we fall

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Speaker 1: off the bottom of it? Right? And why does the

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Speaker 1: stuff in the sky not fall to the earth, Because

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Speaker 1: like you drop an apple, it does fall. You don't

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Speaker 1: need Newton to observe apples falling to see that apples

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Speaker 1: do fall. So this is the very natural next question

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Speaker 1: for Aristotle, and this is where his theory sort of

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Speaker 1: falls apart, because his theory here is sort of just

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Speaker 1: like well, because he says apples and people are made

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Speaker 1: out of a certain kind of stuff, which we'll call

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Speaker 1: like earthy stuff, and earthy stuff is defined as stuff

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Speaker 1: that falls to the center of the universe for no reason.

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Speaker 1: That's just the nature of earthy stuff to do. And

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Speaker 1: heaveny stuff, star stuff doesn't it's embedded in crystal spheres

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Speaker 1: and so doesn't fall. And so like, why don't we

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Speaker 1: fall off the surface of the earth, Because it's not

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Speaker 1: in our nature to fall off the surface of the earth.

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Speaker 1: We are made out of earthy stuff, and everything falls

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Speaker 1: towards the center of the universe, which is the center

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Speaker 1: of the Earth, and everything out in the heavens is

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Speaker 1: not made of that stuff, and so it doesn't fall

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Speaker 1: to the earth. And it seems kind of quaint, now,

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Speaker 1: doesn't it.

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Speaker 2: Yes, Yeah, why don't I go to California? Well, because

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Speaker 2: I'm made out of Virginia, and so I tend to

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Speaker 2: fall into Virginia. And yes, and you're made of like

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Speaker 2: crystals that stay in California.

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Speaker 1: Yes, we are made of crystals out here exactly, hence

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Speaker 1: our shimmering lifestyle. And because stuff doesn't fall to the earth,

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Speaker 1: it's made out of heavenly stuff, and therefore it's perfect

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Speaker 1: and it moves in perfect circles. And this is the

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Speaker 1: first idea, that the Earth is at the center and

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Speaker 1: everything moves around it. And you might initially think like, well,

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Speaker 1: this is kind of a goofy idea, right, why did

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Speaker 1: they come up with this plan? And this is the

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Speaker 1: first place where I think the Greeks don't get enough

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Speaker 1: credit and the story is more nuanced than people understand.

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Speaker 1: Because the Greeks considered the idea that the Earth was

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Speaker 1: not at the center, they thought about, well, what if

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Speaker 1: the Sun is at the center? You know, could that be?

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Speaker 1: And they examined what that would mean for the Solar

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Speaker 1: system and they actually thought of a way to test it,

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Speaker 1: which is super cool, right, because you shouldn't just sit

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Speaker 1: in your toga and eat olives and think about the universe.

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Speaker 1: You should figure out a way to force the universe

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Speaker 1: to reveal to you the truth. Right, That's what experimental

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Speaker 1: physics is all about. And they realized that if the

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Speaker 1: Earth was not at the center of the universe, if

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Speaker 1: it moved around the Sun. Right, if the Sun was

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Speaker 1: at the center and the Earth moved, they should be

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Speaker 1: able to tell because they should see the stars wiggling.

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Speaker 2: Oh and is there a technical name for wiggling?

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Speaker 1: Are you insisting that I use a Latin term instead

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Speaker 1: of explaining the concepts?

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Speaker 2: No, No, let's stick with wiggling. That's it the whole episode.

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Speaker 2: I want you to stick with wiggling.

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Speaker 1: Well, you want to learn more about it, You're going

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Speaker 1: to need to know the official term, which is parallax,

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Speaker 1: but we call it stars wiggling.

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Speaker 2: Oh oh oh wait, So what I want to explain?

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Speaker 2: A species?

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Speaker 4: Is it?

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Speaker 2: Okay? If I just say, well, the listeners might want

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Speaker 2: to know more about you Florcis california asis, which is

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Speaker 2: why I need to tell you the species name.

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Speaker 1: I didn't realize that worked if anybody actually wanted to

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Speaker 1: know more, and.

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Speaker 2: How who would not want to know more about brain

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Speaker 2: infecting parasites a fish?

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Speaker 1: Hard to imagine? Hard to imagine?

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Speaker 2: All right, all right, para got it? Stars wiggling is

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Speaker 2: called parallax.

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Speaker 1: Yeah, exactly. And this is something that's very easy to understand.

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Speaker 1: This is actually how your eyes work to see distance.

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Speaker 1: Like if you hold your thumb out in front of

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Speaker 1: you and you look at it with one eye versus

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Speaker 1: the other eye, it moves right, It's not in the

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Speaker 1: same location relative to the two eyes, So your two

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Speaker 1: eyes have a different view of your thumb, and as

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Speaker 1: your thumb gets further away, the different strengths and as

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Speaker 1: your thumb gets closed through to your eyes, the different

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Speaker 1: gets larger, and this is a binocular vision. This is

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Speaker 1: how your brain can tell how far away something is.

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Speaker 1: When a basketball is flying towards your head, your brain

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Speaker 1: does this calculation based on the different view from the

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Speaker 1: two eyeballs to tell you how close is it right,

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Speaker 1: how rapidly is it approaching? And so you can do

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Speaker 1: the same thing with the Earth. If the Earth was

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Speaker 1: moving around the Sun, then we should get two views

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Speaker 1: of the heavens at different times of year, like in

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Speaker 1: June and in December. We would have a different relationship

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Speaker 1: to the stars, and we should see them move, right,

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Speaker 1: we should see them wiggle. And they looked. They looked

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Speaker 1: at the stars unlike my kids, and they did not

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Speaker 1: see them wiggle. And they said, oh, look, the stars

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Speaker 1: are not wiggling. Therefore, because the stars must be close

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Speaker 1: enough to wiggle if we were moving, we are not moving.

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Speaker 1: And that was the flaw in their logic. They could

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Speaker 1: not fathom that the stars were far enough away to

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Speaker 1: be wiggling but invisibly, because they were so crazy far away.

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Speaker 1: And they said, well, the stars can't be that far away,

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Speaker 1: and we don't see them wiggling. Therefore the Earth is

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Speaker 1: not moving, and that is solid logic.

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Speaker 2: But their stars are so tiny, how could they not

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Speaker 2: consider it? Well, you know what I should. That is

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Speaker 2: impressive that they did the experiments and they figured out parallax.

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Speaker 2: That like props to the Greeks exactly in their togas.

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Speaker 1: And of course now we know with hindsight that the

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Speaker 1: stars were wiggling. It's just that the wiggle is so

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Speaker 1: small because the stars are crazy bonkers far away, so

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Speaker 1: much further away than they could even ever imagine, so

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Speaker 1: far away that we didn't see parallax. We couldn't measure

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Speaker 1: it until eighteen thirty eight, fairly recently. This was just

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Speaker 1: a theoretical concept for a very very long time and

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Speaker 1: turns out to be quite relevant to this story. So

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Speaker 1: the Greeks a thought of parallax, then they ruled out

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Speaker 1: a sun centered universe because they didn't see it. There's

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Speaker 1: a logical flaw there, But you got to give them

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Speaker 1: props for using experimental data, for actually testing these two theories.

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Speaker 1: And if I was in their shoes, I would probably

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Speaker 1: come to the same conclusion.

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Speaker 2: Yeah, yeah, this is the kind of stuff that keeps

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Speaker 2: me up at night thinking, oh, my gosh, what else

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Speaker 2: do we think, like, oh, yeah, well we thought of

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Speaker 2: that and we've ruled it out exactly. What else?

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Speaker 1: You make one very reasonable sounding assumption the stars are

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Speaker 1: not crazy bonkers distance away, and you go down the

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Speaker 1: wrong track for a thousand.

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Speaker 2: Years, yeah, or more than a thousand years. But yes,

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Speaker 2: all right, let's take a break and when we get

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Speaker 2: back we will jump in to the ideas of Ptolemy

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Speaker 2: with the silent p.

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Speaker 1: Kelly, you are inviting some Greek speaker to write in

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Speaker 1: and tell us that we are mispronouncing Ptolemy. Maybe there's

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Speaker 1: just like a really subtle pe in there. Oh, I

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Speaker 1: don't not allowed to do it. Greek speakers write in

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Speaker 1: and tell us if we are mangling Ptolemy and pterodactyls.

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Speaker 2: Oh, I mean, nobody's going to be surprised names. But

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Speaker 2: all right, let us know.

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Speaker 1: So. The first problem with Aristotle's theory that things in

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Speaker 1: heaven are perfect and move in perfect circles is that

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Speaker 1: they don't. Right, If you follow the planets, you can

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Speaker 1: see that they do not move in perfect circles in

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Speaker 1: the heavens. They go sometimes into retrograde. This is not

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Speaker 1: an astrology podcast. We're not talking about, you know, whether

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Speaker 1: you should be making big moves in your romance life

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Speaker 1: when mercury is in retrograde. Retrograde is also an astronomical thing.

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Speaker 1: It's when planets change their apparent direction in the sky.

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Speaker 2: Are they actually changing direction or do they just look

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Speaker 2: like they're changing direction because of how we're moving?

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Speaker 1: What's the difference? I mean, everything is relative, right, and

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Speaker 1: so we are looking at the motion of the planet

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Speaker 1: against the background stars from our point of view. So

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Speaker 1: from the point of view of the Sun, planets don't

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Speaker 1: change direction. They move in an orbit going the same

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Speaker 1: direction all the time. But planets move at different speeds

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Speaker 1: around the Sun, and so sometimes they can pass each other.

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Speaker 1: So from our point of view, sometimes it looks like

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Speaker 1: they're moving one way, and then we pass them, so

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Speaker 1: they're going backwards, and then it looks like they're moving

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Speaker 1: forwards again, just like you know, if you're on the

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Speaker 1: highway and somebody is really far ahead of you, you

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Speaker 1: can tell that they're going forwards because they're passing stuff right,

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Speaker 1: But then as you pass them, it looks momentarily like

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Speaker 1: they're going backwards relative to you. Right in your car's window,

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Speaker 1: they're going backwards. Then once you're far away from them again,

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Speaker 1: you can tell, oh, look they're going forwards relative to

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Speaker 1: the background mountains.

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Speaker 2: Got it.

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Speaker 1: That's sort of what's happening with the planets. If you

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Speaker 1: look at Mars and you write down its location in

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Speaker 1: the sky every night, you'll see it moving through the ecliptic,

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Speaker 1: and then you'll see it go backwards and then go

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Speaker 1: forwards again. It does this like s shaped zigzag. And

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Speaker 1: that was a big problem for Aristotle's theory that like

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Speaker 1: everything is perfect in the heavens and moves in these

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Speaker 1: perfect crystalline circles.

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00:22:33,960 --> 00:22:35,320
Speaker 2: What is the ecliptic?

438
00:22:35,720 --> 00:22:38,679
Speaker 1: The ecliptic is the plane of the Solar system, and

439
00:22:38,800 --> 00:22:40,960
Speaker 1: so everything in the Solar System is roughly in the

440
00:22:40,960 --> 00:22:43,879
Speaker 1: same plane. Right. The Sun rotates, and it rotates around

441
00:22:43,880 --> 00:22:47,040
Speaker 1: an axis, and a plane perpendicular to that axis has

442
00:22:47,080 --> 00:22:49,119
Speaker 1: all the planets in it. So if you're on the

443
00:22:49,160 --> 00:22:51,239
Speaker 1: Earth and you track the motion of the Sun, it

444
00:22:51,320 --> 00:22:54,240
Speaker 1: moves in a line through the sky that's the ecliptic,

445
00:22:54,680 --> 00:22:57,720
Speaker 1: and all the planets tend to move in that same line.

446
00:22:58,160 --> 00:23:00,400
Speaker 1: So if you're looking up in the night sky, shouldn't

447
00:23:00,400 --> 00:23:03,040
Speaker 1: just see planets everywhere? Willy nilly, they're all in the

448
00:23:03,040 --> 00:23:05,439
Speaker 1: same plane in the Solar system, which is a line

449
00:23:05,520 --> 00:23:06,160
Speaker 1: in our sky.

450
00:23:06,400 --> 00:23:07,520
Speaker 2: Got it? Okay?

451
00:23:07,640 --> 00:23:11,000
Speaker 1: All right, So to explain how to planets sometimes zigzag,

452
00:23:11,119 --> 00:23:15,800
Speaker 1: they had to add the famously mocked epicycles. Right, They're like, okay,

453
00:23:15,840 --> 00:23:18,000
Speaker 1: we're not giving up on circles. The Greeks love their

454
00:23:18,040 --> 00:23:20,840
Speaker 1: geometry in their circles, but they're just gonna have circles

455
00:23:21,119 --> 00:23:25,520
Speaker 1: within circles. So now Mars moves in a circle around

456
00:23:25,520 --> 00:23:28,920
Speaker 1: the Earth, but in that circle isn't Mars, it's another circle.

457
00:23:29,359 --> 00:23:31,760
Speaker 1: So Mars is moving within a little circle, and that

458
00:23:31,800 --> 00:23:34,280
Speaker 1: little circle is moving within a bigger circle.

459
00:23:34,760 --> 00:23:37,440
Speaker 2: So is it like every once in a while it'll

460
00:23:37,440 --> 00:23:40,360
Speaker 2: stop and like take a little walk around a cul

461
00:23:40,359 --> 00:23:43,879
Speaker 2: de sac, or is it just constantly doing like purowets

462
00:23:44,320 --> 00:23:46,240
Speaker 2: as it goes around in its big circle.

463
00:23:46,320 --> 00:23:49,040
Speaker 1: It's constantly going around the little circle, and the little

464
00:23:49,040 --> 00:23:52,040
Speaker 1: circle is constantly going around the big circle. Oh wow.

465
00:23:52,240 --> 00:23:54,639
Speaker 1: And the thing about this theory is that it seems

466
00:23:54,680 --> 00:23:57,520
Speaker 1: kind of ridiculous, but it worked really really well, Like

467
00:23:57,960 --> 00:24:00,760
Speaker 1: compared to the previous theory with no circles, thin circles,

468
00:24:01,160 --> 00:24:03,600
Speaker 1: it could really describe the data and you had to

469
00:24:03,600 --> 00:24:05,680
Speaker 1: take a bunch of measurements, and it was a lot

470
00:24:05,760 --> 00:24:08,520
Speaker 1: of tedious calculations to find all the parameters, like how

471
00:24:08,520 --> 00:24:11,159
Speaker 1: big is this circle? How fast is it moving? And

472
00:24:11,200 --> 00:24:13,280
Speaker 1: there's a guy whose job there was to do this

473
00:24:13,359 --> 00:24:16,359
Speaker 1: in the twelve hundreds, and he's famous for saying, quote,

474
00:24:16,560 --> 00:24:18,760
Speaker 1: had I been present at the creation of the universe,

475
00:24:18,800 --> 00:24:26,040
Speaker 1: I would have preferred a simpler design. Amazing, But for

476
00:24:26,119 --> 00:24:29,320
Speaker 1: fifteen hundred years, this is how people understood the motion

477
00:24:29,520 --> 00:24:32,800
Speaker 1: of the planets in the heavens. And it worked. You know,

478
00:24:32,880 --> 00:24:36,840
Speaker 1: it described the data really well. So like, yes, circles

479
00:24:36,840 --> 00:24:39,760
Speaker 1: within circles or epicycles is used to describe the scenario

480
00:24:39,760 --> 00:24:43,280
Speaker 1: where you like made your theory too complicated, too baroque.

481
00:24:43,560 --> 00:24:45,960
Speaker 1: You know, you had to add too many wheels within

482
00:24:46,000 --> 00:24:49,320
Speaker 1: wheels to fit the data, but it did work. Didn't

483
00:24:49,320 --> 00:24:51,960
Speaker 1: fit the data right, And it's just two layers deep.

484
00:24:52,000 --> 00:24:55,400
Speaker 1: It's not like circles within circles within circles within circles, right,

485
00:24:55,920 --> 00:24:59,840
Speaker 1: Just circles within circles, just two layers of circles described

486
00:25:00,040 --> 00:25:02,160
Speaker 1: what was happening in the heavens for the first time ever.

487
00:25:02,520 --> 00:25:04,840
Speaker 1: So like that's a big step forward folks.

488
00:25:05,040 --> 00:25:08,199
Speaker 2: We really don't know of anyone who was like, actually, like,

489
00:25:08,320 --> 00:25:10,280
Speaker 2: wouldn't it all just be easier if we put the

490
00:25:10,320 --> 00:25:11,199
Speaker 2: sun in the center.

491
00:25:11,280 --> 00:25:13,480
Speaker 1: Guys, That theory was out there, but it was refuted

492
00:25:13,480 --> 00:25:14,240
Speaker 1: by parallax.

493
00:25:14,560 --> 00:25:15,720
Speaker 2: Oh okay, we had.

494
00:25:15,560 --> 00:25:17,640
Speaker 1: A reason to reject that theory.

495
00:25:17,640 --> 00:25:18,320
Speaker 2: Right, got it.

496
00:25:18,400 --> 00:25:20,520
Speaker 1: Okay, people had thought of it and it was in

497
00:25:20,600 --> 00:25:22,960
Speaker 1: the bin, right Like, that theory didn't work.

498
00:25:22,880 --> 00:25:25,080
Speaker 2: Got it? Got it? So everyone was reminded of parallax,

499
00:25:25,119 --> 00:25:29,159
Speaker 2: and we still didn't realize the stars were very far away. Yeah, exactly, Okay,

500
00:25:29,840 --> 00:25:30,560
Speaker 2: who's next?

501
00:25:30,880 --> 00:25:33,640
Speaker 1: All right? So next up is a famous player, Copernicus

502
00:25:33,720 --> 00:25:36,520
Speaker 1: in the fifteen hundreds, and there's a lot of stories

503
00:25:36,560 --> 00:25:39,399
Speaker 1: out there a by Copernicus that he's often described as

504
00:25:39,400 --> 00:25:42,600
Speaker 1: a Polish priest, but he wasn't actually a priest. He

505
00:25:42,760 --> 00:25:44,879
Speaker 1: was a canon of the cathedral, which is more like

506
00:25:44,960 --> 00:25:48,040
Speaker 1: a church administer who was never ordained as a priest.

507
00:25:48,480 --> 00:25:50,760
Speaker 1: But you know, he was part of the church and

508
00:25:50,800 --> 00:25:53,720
Speaker 1: he held administry to post his whole life, and he

509
00:25:53,840 --> 00:25:57,560
Speaker 1: was not against the church. He developed his theory of

510
00:25:57,760 --> 00:26:00,840
Speaker 1: heliocentrism that the sun was at the seend, but he

511
00:26:00,880 --> 00:26:04,119
Speaker 1: didn't want to like attack the church or embarrass the church,

512
00:26:04,680 --> 00:26:07,879
Speaker 1: and so famously he withheld publishing his theory and it

513
00:26:07,920 --> 00:26:11,879
Speaker 1: was only published on his deathbed. So he got the

514
00:26:11,920 --> 00:26:15,480
Speaker 1: first printed copy of his theory May twenty fourth, fifteen

515
00:26:15,560 --> 00:26:17,560
Speaker 1: forty three, the day he died.

516
00:26:17,880 --> 00:26:20,720
Speaker 2: Wow. Okay, so that sounds less like he didn't want

517
00:26:20,760 --> 00:26:23,439
Speaker 2: to embarrass the church and more like he was worried

518
00:26:23,440 --> 00:26:26,080
Speaker 2: about his own skin. If he still wants it to

519
00:26:26,119 --> 00:26:28,720
Speaker 2: come out, but not until it can't hurt him anymore.

520
00:26:29,920 --> 00:26:33,119
Speaker 1: Yeah, exactly. There's a lot of complicated stuff in here. Also,

521
00:26:33,160 --> 00:26:36,240
Speaker 1: it turns out that the printer who printed his book,

522
00:26:36,560 --> 00:26:40,919
Speaker 1: Andreas Osander, was trying to like minimize the impact on

523
00:26:41,480 --> 00:26:44,639
Speaker 1: the church, and so he added a preface which said, like,

524
00:26:44,720 --> 00:26:47,280
Speaker 1: you know, this is just like mathematics, this is not

525
00:26:47,520 --> 00:26:48,800
Speaker 1: the truth or anything.

526
00:26:49,359 --> 00:26:51,560
Speaker 2: Oh slice, I know.

527
00:26:52,000 --> 00:26:54,159
Speaker 1: So this might have also helped a little bit, but

528
00:26:54,160 --> 00:26:56,920
Speaker 1: probably Copernicus would have been furious or who knows. Maybe

529
00:26:56,960 --> 00:26:59,200
Speaker 1: he wanted to, like, you know, not embarrass the church,

530
00:26:59,240 --> 00:27:01,920
Speaker 1: and he would have agreed with that, But his motivation

531
00:27:02,160 --> 00:27:06,160
Speaker 1: was also religious. He just thought that Ptolemy's theory circles

532
00:27:06,160 --> 00:27:09,360
Speaker 1: within circles was kind of ugly and it didn't reflect

533
00:27:09,359 --> 00:27:12,639
Speaker 1: like the divine work of the best and greatest artist.

534
00:27:13,200 --> 00:27:15,320
Speaker 1: So he wanted to put the Sun at the center,

535
00:27:16,119 --> 00:27:18,879
Speaker 1: not because he had any insight into astronomy, and not

536
00:27:19,080 --> 00:27:22,040
Speaker 1: because it explained the data any better. In fact, it

537
00:27:22,080 --> 00:27:26,159
Speaker 1: explained the data worse, but because he just felt like

538
00:27:26,240 --> 00:27:28,880
Speaker 1: the Sun should be at the center, because that made

539
00:27:28,920 --> 00:27:32,920
Speaker 1: the explanation simpler. You no longer needed circles. Within circles,

540
00:27:33,320 --> 00:27:35,879
Speaker 1: you could explain retrograde motion. So you put the Sun

541
00:27:35,960 --> 00:27:38,080
Speaker 1: at the center, and now you can just have everything

542
00:27:38,160 --> 00:27:39,840
Speaker 1: moving in a circle around the Sun.

543
00:27:40,600 --> 00:27:42,760
Speaker 2: But what about parallax.

544
00:27:43,160 --> 00:27:45,760
Speaker 1: Yeah, so this does not solve the parallax problem, right,

545
00:27:45,800 --> 00:27:48,439
Speaker 1: and so this is the reason why people were not

546
00:27:48,520 --> 00:27:52,280
Speaker 1: going for heliocentrism for fifteen hundred years. His new theory

547
00:27:52,520 --> 00:27:56,439
Speaker 1: does not solve that problem. He suggested, Well, maybe the

548
00:27:56,480 --> 00:28:00,239
Speaker 1: stars are just too far away for us to notice, right,

549
00:28:00,440 --> 00:28:04,639
Speaker 1: good idea, Copernicus every thought, hah, that's ridiculous, what are

550
00:28:04,640 --> 00:28:07,280
Speaker 1: you talking about. But the other thing I think it's

551
00:28:07,320 --> 00:28:10,240
Speaker 1: important to understand is that when he moves the Sun

552
00:28:10,280 --> 00:28:12,679
Speaker 1: to the center of the Solar system, it does not

553
00:28:12,880 --> 00:28:16,120
Speaker 1: give a better description of the data. Oh so, even

554
00:28:16,160 --> 00:28:18,480
Speaker 1: though it's like, we know it's true and it feels

555
00:28:18,520 --> 00:28:21,560
Speaker 1: like we're getting towards the truth. His theory did not

556
00:28:21,720 --> 00:28:27,440
Speaker 1: describe observations any better than Ptolemy's theory of circles within circles. Right,

557
00:28:28,280 --> 00:28:30,920
Speaker 1: it's simpler, but Ptolemy had this flexibility in his theory.

558
00:28:30,960 --> 00:28:33,920
Speaker 1: It's a little baroque and complicated, but it could describe

559
00:28:33,920 --> 00:28:37,639
Speaker 1: the data. So what is heliocentrism from Copernicus really get you?

560
00:28:38,080 --> 00:28:40,760
Speaker 1: It can't explain parallax unless you believe the stars are

561
00:28:40,800 --> 00:28:43,040
Speaker 1: zuper duper far away, for which there was no evidence,

562
00:28:43,640 --> 00:28:46,320
Speaker 1: and it doesn't describe the data any better. So I

563
00:28:46,320 --> 00:28:49,800
Speaker 1: think people typically like this was the revolution in astronomy,

564
00:28:49,960 --> 00:28:51,000
Speaker 1: but it really wasn't.

565
00:28:51,240 --> 00:28:53,080
Speaker 2: Okay, it's just pretty, it's just.

566
00:28:53,000 --> 00:28:53,920
Speaker 1: A little prettier.

567
00:28:54,400 --> 00:28:59,280
Speaker 2: Exactly was that the dominant theory or was this just

568
00:28:59,600 --> 00:29:02,160
Speaker 2: a theory that was out there, because from what you've

569
00:29:02,200 --> 00:29:04,120
Speaker 2: said to me, it's not clear that this should have

570
00:29:04,160 --> 00:29:06,400
Speaker 2: become immediately the dominant theory.

571
00:29:06,480 --> 00:29:09,480
Speaker 1: Yeah, what we really needed at this point was better data. Okay,

572
00:29:09,600 --> 00:29:12,280
Speaker 1: you know the reason we couldn't tell the difference between

573
00:29:12,600 --> 00:29:15,080
Speaker 1: the two theories that both of them described the data

574
00:29:15,200 --> 00:29:18,680
Speaker 1: is the data was kind of fuzzy. This is pre Galileo. Right,

575
00:29:18,760 --> 00:29:21,240
Speaker 1: So we don't have telescopes looking at the sky taking

576
00:29:21,240 --> 00:29:25,160
Speaker 1: careful measurements. This is all naked eye astronomy, and so

577
00:29:25,240 --> 00:29:28,720
Speaker 1: that really relies on like people's ability to take measurements.

578
00:29:29,280 --> 00:29:33,000
Speaker 1: And so it wasn't until Tico Brahe who built a

579
00:29:33,000 --> 00:29:36,680
Speaker 1: world class observatory we're using money from King Frederick of

580
00:29:36,760 --> 00:29:41,240
Speaker 1: Denmark and took really careful observations. He got higher quality

581
00:29:41,320 --> 00:29:44,560
Speaker 1: data that finally let us move forward and understands something

582
00:29:44,560 --> 00:29:45,720
Speaker 1: else about the universe.

583
00:29:46,400 --> 00:29:49,640
Speaker 2: So I think we probably can't have a conversation about

584
00:29:49,640 --> 00:29:55,560
Speaker 2: good old Tiko without talking about his nose. So tell

585
00:29:55,640 --> 00:29:56,480
Speaker 2: us the nose story.

586
00:29:56,760 --> 00:30:00,320
Speaker 1: So Tiko brahe kind of a crazy dude and kind

587
00:30:00,320 --> 00:30:04,040
Speaker 1: of unhinged and also a little bit mean. And when

588
00:30:04,080 --> 00:30:06,960
Speaker 1: he was twenty he fought a duel with a fellow

589
00:30:07,040 --> 00:30:10,840
Speaker 1: Danish nobleman over math. Right, they had an argument about

590
00:30:10,840 --> 00:30:13,520
Speaker 1: like who was the better mathematician, and they found a

591
00:30:13,600 --> 00:30:16,920
Speaker 1: duel like with swords, and he lost a big chunk

592
00:30:16,920 --> 00:30:19,720
Speaker 1: of his nose. And so for the rest of his

593
00:30:19,800 --> 00:30:23,920
Speaker 1: life he had a prosthetic nose which was like brass

594
00:30:24,040 --> 00:30:26,040
Speaker 1: or maybe a silver gold alloy that he had like

595
00:30:26,080 --> 00:30:29,040
Speaker 1: stick on because otherwise he just looked really weird. And

596
00:30:29,080 --> 00:30:32,360
Speaker 1: you can't be like part of polite society with a

597
00:30:32,440 --> 00:30:35,440
Speaker 1: huge slice of your nose taken out. So he walked

598
00:30:35,480 --> 00:30:38,280
Speaker 1: around with this like box of adhesive past to stick

599
00:30:38,320 --> 00:30:39,880
Speaker 1: this fake nose onto his.

600
00:30:39,960 --> 00:30:43,240
Speaker 2: Face, which I think is a failing of polite society

601
00:30:43,360 --> 00:30:45,760
Speaker 2: back then and remains to be a failing of polite

602
00:30:45,760 --> 00:30:49,160
Speaker 2: society today. We should all be much more chill. But anyway, but.

603
00:30:49,160 --> 00:30:52,440
Speaker 1: In fifteen seventy six, King Frederick of Denmark gave him

604
00:30:52,480 --> 00:30:55,360
Speaker 1: an island. This is the island of Then, which I've

605
00:30:55,400 --> 00:30:58,840
Speaker 1: been to. It's a beautiful place. You can bike around,

606
00:30:58,960 --> 00:31:03,560
Speaker 1: it's gorgeous. He has a castle there, Ranimbour, Castle of

607
00:31:03,600 --> 00:31:08,640
Speaker 1: the Heavens, later renamed Castle of the Stars Stiernobor, And

608
00:31:08,680 --> 00:31:12,840
Speaker 1: it's essentially one of the first like astronomical research facilities

609
00:31:12,960 --> 00:31:15,600
Speaker 1: in the world, you know, like built to see the stars,

610
00:31:15,640 --> 00:31:17,000
Speaker 1: to take careful measurements.

611
00:31:17,400 --> 00:31:21,320
Speaker 2: So if you have a facility that's gigantic, you probably

612
00:31:21,360 --> 00:31:23,400
Speaker 2: need a lot of people to work at that facility.

613
00:31:23,440 --> 00:31:26,520
Speaker 2: What was it like working for good old Bray.

614
00:31:26,640 --> 00:31:29,520
Speaker 1: Yeah, so Rahi was not a kind employer, you know.

615
00:31:29,640 --> 00:31:32,520
Speaker 1: He was famous for being brutal to the local peasants,

616
00:31:33,000 --> 00:31:35,840
Speaker 1: you know, demanding all sorts of stuff from them. He

617
00:31:35,920 --> 00:31:38,160
Speaker 1: was also a really weird guy. He had like an

618
00:31:38,200 --> 00:31:41,640
Speaker 1: elk that he kept in his house and sometimes he

619
00:31:41,640 --> 00:31:43,520
Speaker 1: would feed it too much beer and it would fall

620
00:31:43,520 --> 00:31:46,960
Speaker 1: down the stairs. Like this was a weird dude. He

621
00:31:47,000 --> 00:31:49,880
Speaker 1: apparently died of a bladder infection from sitting at a

622
00:31:49,920 --> 00:31:52,520
Speaker 1: royal banquet for too long and refusing to get up

623
00:31:52,560 --> 00:31:56,160
Speaker 1: to urinate, which was apparently rude, and rupturing his bladder

624
00:31:56,160 --> 00:31:59,040
Speaker 1: because of that. So he was definitely a weird guy.

625
00:31:59,120 --> 00:32:02,080
Speaker 1: But this something's about him which resonate with me, Like

626
00:32:02,480 --> 00:32:05,320
Speaker 1: he was trying to look at the heavens and to

627
00:32:05,400 --> 00:32:08,080
Speaker 1: observe things. And there was supposed to be an alignment

628
00:32:08,480 --> 00:32:12,960
Speaker 1: of Jupiter and Saturn, but it happened two days after

629
00:32:13,160 --> 00:32:16,120
Speaker 1: it was predicted, and that's because the measurements were just

630
00:32:16,160 --> 00:32:18,880
Speaker 1: not great, Like we did not have precise measurements of stuff,

631
00:32:19,160 --> 00:32:20,960
Speaker 1: and so predicting what was going to happen in the

632
00:32:20,960 --> 00:32:23,880
Speaker 1: sky is limited by the measurements that we could make.

633
00:32:24,120 --> 00:32:25,960
Speaker 1: So that was his motivation, is like I want to

634
00:32:26,040 --> 00:32:29,520
Speaker 1: understand the heavens better. So he measured the positions of

635
00:32:29,560 --> 00:32:32,880
Speaker 1: celestial objects in the sky to one arc minute a

636
00:32:33,000 --> 00:32:36,239
Speaker 1: sixtieth of a degree, which is a precision of like

637
00:32:36,320 --> 00:32:41,480
Speaker 1: a fingernail at arm's length. Right. These are naked eye observations,

638
00:32:42,360 --> 00:32:43,840
Speaker 1: no telescopes, no lenses.

639
00:32:43,960 --> 00:32:44,960
Speaker 2: Right, that's amazing.

640
00:32:45,040 --> 00:32:48,520
Speaker 1: So this data that he gathered is like ten times

641
00:32:48,680 --> 00:32:52,240
Speaker 1: more accurate than any data anybody's had about the sky.

642
00:32:52,800 --> 00:32:55,680
Speaker 1: And this is what fueled the revolution in astronomy. Is

643
00:32:55,680 --> 00:33:00,400
Speaker 1: like needing to actually describe the universe more precisely, and

644
00:33:00,720 --> 00:33:04,520
Speaker 1: neither the Ptolemaic nor the Copernican models fit that data.

645
00:33:04,600 --> 00:33:06,800
Speaker 1: Oh boy, so you might be expecting, Oh, we take

646
00:33:06,840 --> 00:33:10,040
Speaker 1: better data, and that's when we learned the heliocentrism is

647
00:33:10,080 --> 00:33:12,080
Speaker 1: the truth. Oh no, we take better data and we

648
00:33:12,120 --> 00:33:15,240
Speaker 1: discover neither of those two models actually worked.

649
00:33:15,560 --> 00:33:16,280
Speaker 2: So what do we do.

650
00:33:17,560 --> 00:33:20,440
Speaker 1: Yeah, Tycho could not make this work either, right, and

651
00:33:20,480 --> 00:33:22,440
Speaker 1: the issue, of course was not going to be solved

652
00:33:22,520 --> 00:33:25,600
Speaker 1: until later when Kepler came up with his ideas of ellipses.

653
00:33:25,640 --> 00:33:30,320
Speaker 1: But we're not there yet because Tycho rejected Ptolemy's theory

654
00:33:30,840 --> 00:33:33,160
Speaker 1: that the Earth was at the center of the universe.

655
00:33:33,240 --> 00:33:37,320
Speaker 1: He also rejected Copernicus's theory that the Sun was at

656
00:33:37,320 --> 00:33:41,480
Speaker 1: the center of the universe. He had his own theory,

657
00:33:41,520 --> 00:33:45,160
Speaker 1: the tychonic system of the Solar System, which sounds like

658
00:33:45,160 --> 00:33:47,880
Speaker 1: a diet plan from medieval Europe, but it was like

659
00:33:47,920 --> 00:33:50,240
Speaker 1: a new vision of how the universe might work.

660
00:33:50,720 --> 00:33:53,280
Speaker 2: I hope it doesn't involve drinking beer and sitting at

661
00:33:53,320 --> 00:33:54,800
Speaker 2: a table for a real long time.

662
00:33:54,920 --> 00:33:55,440
Speaker 1: With an elk.

663
00:33:55,720 --> 00:33:56,560
Speaker 2: Sounds dangerous.

664
00:33:58,360 --> 00:34:00,760
Speaker 1: So he liked the idea that the Earth was in

665
00:34:00,800 --> 00:34:04,680
Speaker 1: the center. Tycho said the Earth was a hulking, lazy body,

666
00:34:04,840 --> 00:34:08,279
Speaker 1: unfit for motion, and it made no sense to him

667
00:34:08,360 --> 00:34:10,759
Speaker 1: that the Earth was in motion. And also, remember we

668
00:34:10,760 --> 00:34:13,160
Speaker 1: were not seeing parallax, so he really wanted to keep

669
00:34:13,200 --> 00:34:15,560
Speaker 1: the Earth at the center of the Solar system. But

670
00:34:15,680 --> 00:34:19,480
Speaker 1: he also liked the simplicity of the Copernicus system right

671
00:34:19,520 --> 00:34:21,880
Speaker 1: where you don't have circles within circles, where you can

672
00:34:21,920 --> 00:34:24,920
Speaker 1: explain retrograde motion by having the planets move around the Sun.

673
00:34:25,520 --> 00:34:28,000
Speaker 1: So Tycho was like, hmm, I want the Earth of

674
00:34:28,000 --> 00:34:30,439
Speaker 1: the center and I want the planets to move around

675
00:34:30,440 --> 00:34:34,640
Speaker 1: the Sun. Nolos dos right. I don't think he spoke Spanish,

676
00:34:34,680 --> 00:34:36,720
Speaker 1: but that was the inspiration, right, and it's.

677
00:34:36,600 --> 00:34:43,360
Speaker 2: Probably before that commercial So so that's the Tychonic model

678
00:34:43,400 --> 00:34:45,239
Speaker 2: of the Solar system is you have the Earth of

679
00:34:45,239 --> 00:34:48,960
Speaker 2: the center, the Sun moves around the Earth, and all

680
00:34:48,960 --> 00:34:53,200
Speaker 2: the planets move around the Sun, not around the Earth. Right,

681
00:34:53,440 --> 00:34:54,879
Speaker 2: that's complicated, so.

682
00:34:54,880 --> 00:34:59,560
Speaker 1: It's geo heliocentric. Right. Wow, So the Earth is at

683
00:34:59,560 --> 00:35:02,520
Speaker 1: the center, the Sun moves around the Earth, and all

684
00:35:02,520 --> 00:35:06,160
Speaker 1: the planets orbit the Sun. So like together, our Sun

685
00:35:06,280 --> 00:35:09,000
Speaker 1: is bringing all the planets with it as it orbits

686
00:35:09,080 --> 00:35:11,320
Speaker 1: around the Earth. It's kind of bonkers.

687
00:35:11,680 --> 00:35:14,000
Speaker 2: Does this actually do a great job with the data?

688
00:35:14,200 --> 00:35:17,719
Speaker 1: So you know this explains retrograde motion, right because you

689
00:35:17,800 --> 00:35:20,120
Speaker 1: have the planets moving around the Sun, not the Earth.

690
00:35:20,680 --> 00:35:24,480
Speaker 1: And it explains no parallax observation. We didn't see parallax

691
00:35:24,520 --> 00:35:27,279
Speaker 1: why because the Earth was not moving relative to the

692
00:35:27,320 --> 00:35:30,680
Speaker 1: distant stars. Right. Okay, so this was kind of a

693
00:35:30,719 --> 00:35:33,680
Speaker 1: great idea, and this taiconic model, though you never hear

694
00:35:33,760 --> 00:35:38,080
Speaker 1: about it anymore, survived for centuries and was taken seriously

695
00:35:38,120 --> 00:35:41,120
Speaker 1: for centuries because it fit the data very well.

696
00:35:41,560 --> 00:35:42,040
Speaker 2: Wow.

697
00:35:42,640 --> 00:35:45,400
Speaker 1: Now he still used circles, right, This is pre Kepler,

698
00:35:45,800 --> 00:35:48,520
Speaker 1: so he wasn't actually able to fit his own data

699
00:35:48,600 --> 00:35:52,040
Speaker 1: any better than Ptolemy or Copernicus. Right, anybody still using

700
00:35:52,040 --> 00:35:55,360
Speaker 1: circles for these planets, was still not getting great predictions,

701
00:35:55,400 --> 00:35:59,000
Speaker 1: because actually the planets move in ellipses, not in circles.

702
00:35:59,280 --> 00:36:03,200
Speaker 1: But he did exp plan retrograde motion and parallax observation,

703
00:36:03,920 --> 00:36:07,320
Speaker 1: and Tycho thought that Copernicus's idea that like, the stars

704
00:36:07,360 --> 00:36:10,440
Speaker 1: were so distant and that's why we couldn't observe parallax

705
00:36:10,760 --> 00:36:14,040
Speaker 1: was crazy because he calculated they would have to be

706
00:36:14,120 --> 00:36:17,879
Speaker 1: at least seven hundred times more distant than Saturn, which

707
00:36:17,920 --> 00:36:21,000
Speaker 1: to him was like a bonker's number. If you can

708
00:36:21,040 --> 00:36:23,120
Speaker 1: see their size and you've an estimate of their distance,

709
00:36:23,400 --> 00:36:26,400
Speaker 1: you can calculate how big they must be. And he

710
00:36:26,480 --> 00:36:29,719
Speaker 1: got a number which was huge, much bigger than the Sun.

711
00:36:29,760 --> 00:36:32,359
Speaker 1: And he was like, well that's crazy. Now. Of course

712
00:36:32,360 --> 00:36:35,480
Speaker 1: we know there are some really really big stars out there,

713
00:36:35,480 --> 00:36:38,120
Speaker 1: and they were really onto something, but these numbers were

714
00:36:38,200 --> 00:36:41,160
Speaker 1: just so bonkers to them that they dismissed it. Right,

715
00:36:41,239 --> 00:36:44,760
Speaker 1: So Tiko brahe preferred putting the Earth at the center

716
00:36:44,800 --> 00:36:48,279
Speaker 1: of the Solar system rather than accepting the stars were

717
00:36:48,280 --> 00:36:51,280
Speaker 1: super distant and some of them were super duper big.

718
00:36:51,960 --> 00:36:55,440
Speaker 2: I thought, maybe you said this idea was accepted for centuries,

719
00:36:55,560 --> 00:36:57,680
Speaker 2: and maybe I misheard you, but I thought it looks

720
00:36:57,719 --> 00:37:01,280
Speaker 2: like Kepler in like decades comes up with a better idea.

721
00:37:01,360 --> 00:37:03,880
Speaker 2: But did were Kepler's idea is not so Kepler.

722
00:37:03,560 --> 00:37:07,560
Speaker 1: Soon after Tako Brahey comes up with the idea of ellipses, right,

723
00:37:07,960 --> 00:37:11,279
Speaker 1: because he's brah he's assistant, and he's tasked with this

724
00:37:11,400 --> 00:37:14,120
Speaker 1: job of like, look, I like this theory, but it's

725
00:37:14,160 --> 00:37:16,640
Speaker 1: not really quite working. You can't explain the data. And

726
00:37:16,719 --> 00:37:19,719
Speaker 1: he was struggling and struggling and struggling to make the

727
00:37:20,000 --> 00:37:23,799
Speaker 1: orbit of Mars work in particular. So Kepler couldn't make

728
00:37:23,840 --> 00:37:26,640
Speaker 1: this work. He struggled for years, and finally he was like, Okay,

729
00:37:26,719 --> 00:37:27,640
Speaker 1: let's use ellipses.

730
00:37:28,080 --> 00:37:30,359
Speaker 2: Let's take a break, and when we come back, let's

731
00:37:30,400 --> 00:37:32,640
Speaker 2: go ahead and settle this debate, which is what you'd

732
00:37:32,640 --> 00:37:53,000
Speaker 2: expect us to do with a third segment of our show.

733
00:37:54,480 --> 00:37:56,680
Speaker 2: And we're back, and we are finally going to settle

734
00:37:56,760 --> 00:38:02,960
Speaker 2: this geocentrism heliocentrism debate. What's going on with parallax Daniel,

735
00:38:03,480 --> 00:38:05,640
Speaker 2: Let's settle this thing, right.

736
00:38:05,760 --> 00:38:07,960
Speaker 1: So we have the tom Eg version, the Earth is

737
00:38:08,080 --> 00:38:10,960
Speaker 1: the center. We have the Copernicus version, the sun is

738
00:38:11,000 --> 00:38:14,440
Speaker 1: at the center. We have the ticonic version, which puts

739
00:38:14,480 --> 00:38:16,920
Speaker 1: the Earth of the center and all the other planets

740
00:38:17,040 --> 00:38:20,040
Speaker 1: orbiting the sun right, and none of them are working

741
00:38:20,160 --> 00:38:22,480
Speaker 1: very well. The reason is that all of them are

742
00:38:22,520 --> 00:38:25,560
Speaker 1: still based on circles. All the orbits are circles. So

743
00:38:25,680 --> 00:38:28,400
Speaker 1: Kepler comes in, He's trying hard to make this work.

744
00:38:28,480 --> 00:38:30,520
Speaker 1: He can't make it work. He comes up with the

745
00:38:30,520 --> 00:38:34,919
Speaker 1: idea of ellipses. Right. He adds this to Copernicus's theory. Right,

746
00:38:35,000 --> 00:38:37,919
Speaker 1: So the Kepler view of the universe now is Copernicus,

747
00:38:38,120 --> 00:38:41,600
Speaker 1: but with ellipses instead of with circles. And this matches

748
00:38:41,640 --> 00:38:43,760
Speaker 1: the data. This works really really well.

749
00:38:43,960 --> 00:38:46,480
Speaker 2: And ellipses being long circles.

750
00:38:46,760 --> 00:38:49,640
Speaker 1: Yeah, so ellipses are like the shape of an egg. Right,

751
00:38:49,719 --> 00:38:52,000
Speaker 1: So a circle is perfectly round and ellipse is like

752
00:38:52,000 --> 00:38:53,080
Speaker 1: a swished circle.

753
00:38:53,480 --> 00:38:54,359
Speaker 2: Right, got it.

754
00:38:54,440 --> 00:38:58,560
Speaker 1: And he can also upgrade Ticobry's theory to use ellipses. Right,

755
00:38:58,640 --> 00:39:01,440
Speaker 1: So now the ticonic model can have ellipses, the Copernican

756
00:39:01,520 --> 00:39:04,880
Speaker 1: model can have ellipses. The Tolemag model does not allow

757
00:39:04,920 --> 00:39:08,359
Speaker 1: for ellipses because you know they're going for like perfect circles, right,

758
00:39:08,760 --> 00:39:12,000
Speaker 1: But you can always just add more ellipses to Ptolemy

759
00:39:12,080 --> 00:39:18,120
Speaker 1: so it is possible to fit Ptolemy's theory to Braje's observations.

760
00:39:18,520 --> 00:39:21,400
Speaker 1: You just got to add more and more circles. And

761
00:39:21,440 --> 00:39:24,760
Speaker 1: so it's not really true that Tico Brahe's data killed

762
00:39:24,960 --> 00:39:28,640
Speaker 1: the Totolemaic system, right, because the Ptolemaic system allowed you

763
00:39:28,680 --> 00:39:31,440
Speaker 1: to just add more and more circles as you liked.

764
00:39:32,120 --> 00:39:35,480
Speaker 1: What really killed the Ptolemaic system was Venus.

765
00:39:36,280 --> 00:39:40,400
Speaker 2: What how did the goddess of love kill Ptolemy?

766
00:39:40,560 --> 00:39:43,160
Speaker 1: So remember Ptolemy could always just add more circles no

767
00:39:43,200 --> 00:39:45,480
Speaker 1: matter what data you took. He could actually fit it.

768
00:39:45,880 --> 00:39:50,480
Speaker 1: But Galileo realized that observing Venus would help us understand

769
00:39:50,560 --> 00:39:54,280
Speaker 1: whether Venus was orbiting the Sun or orbiting the Earth.

770
00:39:54,840 --> 00:39:58,760
Speaker 1: So Galileo comes around Lay fifteen hundreds, early sixteen hundreds,

771
00:39:59,080 --> 00:40:02,360
Speaker 1: and he realized that your view of Venus would depend

772
00:40:02,440 --> 00:40:05,960
Speaker 1: on whether it's orbiting the Earth or orbiting the Sun. Okay,

773
00:40:06,360 --> 00:40:09,000
Speaker 1: So if Venus is orbiting the Sun, right, it's moving

774
00:40:09,040 --> 00:40:11,319
Speaker 1: around the Sun, there's going to be some point at

775
00:40:11,320 --> 00:40:13,880
Speaker 1: which Venus is on the other side of the Sun

776
00:40:14,280 --> 00:40:16,800
Speaker 1: than we are. Right, then the Sun is going to

777
00:40:16,880 --> 00:40:21,600
Speaker 1: be between Earth and Venus. And in that configuration, we

778
00:40:21,640 --> 00:40:25,279
Speaker 1: should see an entire side of Venus lit up. Right,

779
00:40:25,320 --> 00:40:27,800
Speaker 1: We should see like a full side of Venus. Venus

780
00:40:27,800 --> 00:40:31,000
Speaker 1: should be like full in the sky, not a crescent,

781
00:40:31,080 --> 00:40:32,279
Speaker 1: but a full circle in the.

782
00:40:32,239 --> 00:40:34,880
Speaker 2: Sky when it's on the other side of the sun.

783
00:40:34,760 --> 00:40:36,520
Speaker 1: When it's on the other side of the sun, because

784
00:40:36,520 --> 00:40:38,800
Speaker 1: in the light of the Sun hits the whole surface

785
00:40:38,840 --> 00:40:41,560
Speaker 1: of Venus, and then we see that whole thing, just

786
00:40:41,640 --> 00:40:43,440
Speaker 1: like how you can see a full moon. Right, you

787
00:40:43,440 --> 00:40:45,719
Speaker 1: can see a full moon when the whole side of

788
00:40:45,719 --> 00:40:48,040
Speaker 1: the moon is being illuminated by the sun.

789
00:40:48,560 --> 00:40:50,799
Speaker 2: Okay, I guess when I'm imagining it's on the other

790
00:40:50,840 --> 00:40:52,359
Speaker 2: side of the Sun, I can't see it because it's

791
00:40:52,400 --> 00:40:55,560
Speaker 2: blocked by the sun. So what is my mental model

792
00:40:55,719 --> 00:40:56,360
Speaker 2: missing there?

793
00:40:56,800 --> 00:40:59,040
Speaker 1: You're right that if it's exactly behind the sun, you

794
00:40:59,040 --> 00:41:01,239
Speaker 1: couldn't see it. But now let it move like a

795
00:41:01,320 --> 00:41:03,920
Speaker 1: little bit around from behind the sun and you can

796
00:41:03,960 --> 00:41:07,040
Speaker 1: see essentially the entire surface of Venus is lit up

797
00:41:07,120 --> 00:41:08,120
Speaker 1: by the sun. Right.

798
00:41:08,360 --> 00:41:08,760
Speaker 2: Perfect.

799
00:41:08,840 --> 00:41:13,000
Speaker 1: Okay, So now in Ptolemy's model, Venus is orbiting the

800
00:41:13,120 --> 00:41:16,400
Speaker 1: Earth and not orbiting the Sun, and so never is

801
00:41:16,480 --> 00:41:19,840
Speaker 1: it on the other side of the Sun. In Ptolemy's model,

802
00:41:20,400 --> 00:41:23,200
Speaker 1: Venus has its orbit around the Earth and the Sun

803
00:41:23,280 --> 00:41:26,640
Speaker 1: has its orbit around the Earth, and their relative distances

804
00:41:26,680 --> 00:41:30,680
Speaker 1: are fixed. And so in Ptolemy's model, Venus is always

805
00:41:30,719 --> 00:41:33,720
Speaker 1: between the Earth and the Sun, and so you should

806
00:41:33,760 --> 00:41:37,120
Speaker 1: never see like the full phase of Venus. You always

807
00:41:37,120 --> 00:41:39,920
Speaker 1: see a crescent. Okay, So you can just look you

808
00:41:40,040 --> 00:41:42,000
Speaker 1: just watch Venus, and if you look at Venus, you

809
00:41:42,000 --> 00:41:45,200
Speaker 1: can see that the phases of Venus are perfectly predicted

810
00:41:45,239 --> 00:41:48,400
Speaker 1: by Venus orbiting the Sun instead of orbiting the Earth.

811
00:41:48,920 --> 00:41:51,839
Speaker 1: So it's the phases of Venus that finally kill off

812
00:41:51,880 --> 00:41:53,160
Speaker 1: the Ptolemaic.

813
00:41:52,600 --> 00:41:56,960
Speaker 2: System directed Ptolemy goes down.

814
00:41:57,120 --> 00:41:59,880
Speaker 1: But here's an important wrinkle that I didn't fully understand

815
00:41:59,880 --> 00:42:04,719
Speaker 1: it until recently. It does not kill off Tikobraya system. Right,

816
00:42:05,120 --> 00:42:08,560
Speaker 1: so we have Copernicus who says the Sun is at

817
00:42:08,600 --> 00:42:10,600
Speaker 1: the center and everything is orbiting the Sun. We have

818
00:42:10,680 --> 00:42:14,040
Speaker 1: Tigobrahe who says the Earth is at the center, the

819
00:42:14,200 --> 00:42:16,759
Speaker 1: Sun is orbiting the Earth, and all the planets are

820
00:42:16,840 --> 00:42:20,759
Speaker 1: orbiting the Sun. That's consistent with the phases of Venus. Right,

821
00:42:21,120 --> 00:42:24,800
Speaker 1: So Tiicobrahe system is not killed off by the phases

822
00:42:24,840 --> 00:42:25,400
Speaker 1: of Venus.

823
00:42:25,480 --> 00:42:28,399
Speaker 2: It's still around how do we kill that well off?

824
00:42:28,440 --> 00:42:31,160
Speaker 1: Then, the thing to understand about the difference between the

825
00:42:31,160 --> 00:42:35,759
Speaker 1: Copernicus system and the Tikobrahey system is that even though

826
00:42:35,760 --> 00:42:39,960
Speaker 1: they sound really really different, they're actually totally equivalent. For

827
00:42:40,120 --> 00:42:44,080
Speaker 1: local motion, it's just a coordinate transformation. It just says,

828
00:42:44,120 --> 00:42:46,160
Speaker 1: are you viewing it from the Sun or are you

829
00:42:46,280 --> 00:42:49,360
Speaker 1: viewing it from the Earth. They make exactly the same

830
00:42:49,440 --> 00:42:53,480
Speaker 1: predictions for where things are in the Solar System relative

831
00:42:53,560 --> 00:42:57,680
Speaker 1: to each other. Their only difference is who's moving relative

832
00:42:57,719 --> 00:43:01,000
Speaker 1: to the distant stars, Like is the Earth the motionless

833
00:43:01,040 --> 00:43:04,080
Speaker 1: with respect of those stars? Or is the Sun motionless

834
00:43:04,080 --> 00:43:07,080
Speaker 1: with respect to those stars? Within the Solar system? They're

835
00:43:07,120 --> 00:43:08,440
Speaker 1: exactly the same prediction.

836
00:43:09,040 --> 00:43:12,160
Speaker 2: Okay. And just to remind people like me again whose

837
00:43:12,200 --> 00:43:16,200
Speaker 2: brains don't hold information, Copernicus predicted the Sun at the center,

838
00:43:16,320 --> 00:43:19,319
Speaker 2: the Sun at the center, and Tiko has the Earth

839
00:43:19,320 --> 00:43:21,920
Speaker 2: at the center. The Sun goes around the Earth and

840
00:43:21,960 --> 00:43:23,279
Speaker 2: the planets go around the Sun.

841
00:43:23,640 --> 00:43:26,640
Speaker 1: Yeah, and you said that sounds a lot more complicated. Yeah,

842
00:43:26,640 --> 00:43:28,799
Speaker 1: And it seems more complicated and it's harder to hold

843
00:43:28,840 --> 00:43:32,120
Speaker 1: in your mind. But any prediction it makes is exactly

844
00:43:32,160 --> 00:43:35,680
Speaker 1: the same as the Copernican system. For inside the Solar system,

845
00:43:35,680 --> 00:43:38,960
Speaker 1: it's just a coordinate transformation. It just says, from whose

846
00:43:39,000 --> 00:43:42,120
Speaker 1: perspective are you seeing this? Okay, So the only way

847
00:43:42,120 --> 00:43:45,319
Speaker 1: to tell the difference between these two systems is to ask, well,

848
00:43:45,400 --> 00:43:50,880
Speaker 1: who's moving relative to the distant stars? And you might think, okay, finally,

849
00:43:51,080 --> 00:43:54,279
Speaker 1: here's where parallax has got to come in. Eventually we

850
00:43:54,320 --> 00:43:58,120
Speaker 1: figured it out, parallax, and that's what killed Tikobrai's system.

851
00:43:58,200 --> 00:43:59,920
Speaker 2: Right, maybe wrong.

852
00:44:00,560 --> 00:44:04,279
Speaker 1: It was not parallax that killed off takobraje system. It

853
00:44:04,320 --> 00:44:07,880
Speaker 1: was at something totally different. It was stellar aberration.

854
00:44:08,680 --> 00:44:10,239
Speaker 2: I don't know what that is at all.

855
00:44:10,960 --> 00:44:13,360
Speaker 1: Stellar aberration is super famous in the history of physics

856
00:44:13,360 --> 00:44:16,040
Speaker 1: for killing off the ether theory. That's a whole other

857
00:44:16,120 --> 00:44:19,320
Speaker 1: podcast episode fin But the idea is you can measure

858
00:44:19,320 --> 00:44:22,640
Speaker 1: our velocity relative to the stars by looking at how

859
00:44:22,680 --> 00:44:27,080
Speaker 1: their angle changes during the year. This is different from parallax. Right.

860
00:44:27,440 --> 00:44:30,280
Speaker 1: Parallax just says that if you're in a different location,

861
00:44:30,520 --> 00:44:33,400
Speaker 1: you'll see them at a different point in the sky.

862
00:44:33,440 --> 00:44:36,960
Speaker 1: This is sensitive to our velocity relative to the stars

863
00:44:37,480 --> 00:44:40,319
Speaker 1: because if you imagine, like the light coming from the star,

864
00:44:40,480 --> 00:44:43,080
Speaker 1: it's going to come down your telescope tube. So you

865
00:44:43,120 --> 00:44:45,360
Speaker 1: have to point your tube of your telescope where the

866
00:44:45,400 --> 00:44:49,200
Speaker 1: star is. But if the star is moving right, then

867
00:44:49,239 --> 00:44:51,320
Speaker 1: the light's going to come in at a different angle,

868
00:44:51,640 --> 00:44:54,160
Speaker 1: and so you have to point your telescope tube slightly

869
00:44:54,200 --> 00:44:57,359
Speaker 1: differently in order to catch it, and so the star

870
00:44:57,440 --> 00:45:00,080
Speaker 1: appears at a different place in the sky than it

871
00:45:00,120 --> 00:45:03,920
Speaker 1: really is if it's in motion. Now, if you have

872
00:45:04,080 --> 00:45:07,279
Speaker 1: constant velocity relative to the stars, then you'd see them

873
00:45:07,320 --> 00:45:09,279
Speaker 1: at a shifted angle all year. You wouldn't be able

874
00:45:09,280 --> 00:45:12,840
Speaker 1: to tell anything. But if our velocity changes during the

875
00:45:12,920 --> 00:45:16,360
Speaker 1: year because of our orbit around the Sun, then this aberration,

876
00:45:16,480 --> 00:45:19,640
Speaker 1: this change in angle changes with respect to the year.

877
00:45:20,239 --> 00:45:22,920
Speaker 1: One easy way to think about it is that parallax

878
00:45:23,000 --> 00:45:26,760
Speaker 1: comes from changing your position, while aberration comes from changing

879
00:45:26,760 --> 00:45:30,040
Speaker 1: your velocity. Parallax is the same effect you see when

880
00:45:30,080 --> 00:45:32,239
Speaker 1: you look at your thumb with one eye and then

881
00:45:32,280 --> 00:45:36,160
Speaker 1: the other. Aberration is more like tilting an umbrella ford

882
00:45:36,200 --> 00:45:39,040
Speaker 1: when you're walking through the rain, because your motion changes

883
00:45:39,120 --> 00:45:42,359
Speaker 1: the apparent direction the rain drops are coming from. And

884
00:45:42,680 --> 00:45:46,520
Speaker 1: this was observed one hundred and ten years before parallax,

885
00:45:46,840 --> 00:45:49,960
Speaker 1: and that proves that the Earth is moving relative to

886
00:45:50,000 --> 00:45:52,480
Speaker 1: the distant stars just the way you'd expect if it's

887
00:45:52,600 --> 00:45:55,600
Speaker 1: orbiting the Sun. If you did that measurement on the Sun,

888
00:45:55,719 --> 00:45:59,240
Speaker 1: you'd see much less aberration because the Sun is moving

889
00:45:59,480 --> 00:46:02,279
Speaker 1: less real relative to the distant stars. Okay. And so

890
00:46:02,480 --> 00:46:06,000
Speaker 1: this is what finally killed off Tiko Brahe's theory that

891
00:46:06,080 --> 00:46:09,240
Speaker 1: the Earth was at the center and not moving relative

892
00:46:09,360 --> 00:46:10,560
Speaker 1: to the distant stars.

893
00:46:10,960 --> 00:46:15,520
Speaker 2: Ha ha. Okay. And so now Kepler winds.

894
00:46:15,560 --> 00:46:18,239
Speaker 1: So now Kepler and Copernicus wind And it's not until

895
00:46:18,239 --> 00:46:21,640
Speaker 1: one hundred years later that we observe parallax, the thing

896
00:46:21,680 --> 00:46:25,280
Speaker 1: that the Greek said was the key to understanding whether

897
00:46:25,400 --> 00:46:27,920
Speaker 1: the Earth or the Sun is at the center of

898
00:46:28,000 --> 00:46:31,760
Speaker 1: the Solar system. And this comes because Besel invented something

899
00:46:31,800 --> 00:46:36,640
Speaker 1: called a heliometer, which uses relative measurements rather than absolute measurements.

900
00:46:37,040 --> 00:46:40,239
Speaker 1: So instead of like trying to really precisely measure the

901
00:46:40,320 --> 00:46:43,319
Speaker 1: location of the stars, it just measured the motion of

902
00:46:43,360 --> 00:46:46,640
Speaker 1: the stars. So it's sort of like subtracting away a

903
00:46:46,680 --> 00:46:50,200
Speaker 1: source of your systematic uncertainty to only look at changes

904
00:46:50,320 --> 00:46:54,000
Speaker 1: in your measurements. So really cool story there, but one

905
00:46:54,080 --> 00:46:57,880
Speaker 1: hundred years too late to actually be relevant to this debate.

906
00:46:59,320 --> 00:47:01,080
Speaker 2: What do you think that the takeaways are here because

907
00:47:01,200 --> 00:47:02,920
Speaker 2: like so, you've got a bunch of models that do

908
00:47:02,960 --> 00:47:05,680
Speaker 2: a good job of explaining the data, but they were

909
00:47:05,719 --> 00:47:08,600
Speaker 2: still wrong. But we kept thinking about it and trying

910
00:47:08,600 --> 00:47:10,440
Speaker 2: to do a better and better job. But how would

911
00:47:10,760 --> 00:47:13,640
Speaker 2: what is the Daniel uplifting message here?

912
00:47:14,719 --> 00:47:16,399
Speaker 1: You know, I think that this story is a lot

913
00:47:16,440 --> 00:47:20,160
Speaker 1: more complicated than people usually tell it. You know, I

914
00:47:20,160 --> 00:47:24,080
Speaker 1: think that not widely understood takeaways are that Copernicus and

915
00:47:24,080 --> 00:47:27,640
Speaker 1: Ptolemy both described the pre Kepler data really, really well,

916
00:47:27,920 --> 00:47:30,080
Speaker 1: and the Greeks had a good reason to put the

917
00:47:30,120 --> 00:47:32,680
Speaker 1: Earth at the center of the Solar system, And that

918
00:47:32,800 --> 00:47:34,560
Speaker 1: there was a third player in this whole debate, right,

919
00:47:34,560 --> 00:47:37,880
Speaker 1: Ticobrahe has sort of forgotten. Nobody talks about the Ticonic system,

920
00:47:38,160 --> 00:47:41,120
Speaker 1: even though it survived until the seventeen hundreds, And that

921
00:47:41,200 --> 00:47:46,600
Speaker 1: Kepler's analysis and ellipses didn't actually disprove geocentrism right, It

922
00:47:46,719 --> 00:47:51,000
Speaker 1: just made Ptolemaic less likely because it required more circles.

923
00:47:51,040 --> 00:47:53,799
Speaker 1: Within those circles, it was the phases of Venus that

924
00:47:53,960 --> 00:47:58,080
Speaker 1: finally killed off Ptolemy, and that it wasn't until aberration

925
00:47:58,160 --> 00:48:02,040
Speaker 1: and then eventually parallax that t Obraja system was finally disproven.

926
00:48:02,680 --> 00:48:05,200
Speaker 2: The more data you have, the better you're gonna do.

927
00:48:05,400 --> 00:48:07,160
Speaker 2: We had to know about Venus, we had to know

928
00:48:07,160 --> 00:48:11,000
Speaker 2: about parallax, we had to know about stellar aberrations. All

929
00:48:11,040 --> 00:48:13,680
Speaker 2: of this came together to tell our story exactly.

930
00:48:13,719 --> 00:48:15,480
Speaker 1: And so this tells you that our exploration of the

931
00:48:15,560 --> 00:48:18,320
Speaker 1: universe can go down weird paths for hundreds of years,

932
00:48:18,320 --> 00:48:21,520
Speaker 1: sometimes before somebody takes the right piece of data or

933
00:48:21,719 --> 00:48:24,640
Speaker 1: has the right idea, And that many of the stories

934
00:48:24,680 --> 00:48:29,400
Speaker 1: we tell about the history of scientific discoveries are vastly oversimplified,

935
00:48:29,840 --> 00:48:32,320
Speaker 1: and that if you're standing at the forefront of human

936
00:48:32,360 --> 00:48:35,160
Speaker 1: knowledge at any given moment, it's not always obvious what

937
00:48:35,200 --> 00:48:37,719
Speaker 1: the next step is, even if it seems like it

938
00:48:37,760 --> 00:48:38,440
Speaker 1: in hindsight.

939
00:48:38,880 --> 00:48:42,720
Speaker 2: That's right, all right, Thanks Daniel for this walkthrough science history.

940
00:48:42,760 --> 00:48:46,239
Speaker 2: I had a great time. Until next time, Extraordinaries.

941
00:48:52,200 --> 00:48:54,640
Speaker 1: Thanks everybody for listening. Please go and do us a

942
00:48:54,680 --> 00:48:57,919
Speaker 1: favor and rate the show on whatever podcast app you're using.

943
00:48:58,000 --> 00:48:59,560
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944
00:49:00,160 --> 00:49:04,040
Speaker 2: Daniel and Kelly's Extraordinary Universe is edited by the amazing

945
00:49:04,080 --> 00:49:04,800
Speaker 2: Matt Kesselman.

946
00:49:05,040 --> 00:49:08,279
Speaker 1: He really is a wizard. You can also find us

947
00:49:08,360 --> 00:49:13,440
Speaker 1: online on Blue Sky Instagram and x D and K Universe.

948
00:49:13,520 --> 00:49:14,759
Speaker 1: Come engage with us.

949
00:49:15,000 --> 00:49:18,319
Speaker 2: You can email us at questions at Danielankelly dot org.

950
00:49:18,440 --> 00:49:20,600
Speaker 2: We really do want to hear from you, and you.

951
00:49:20,600 --> 00:49:24,600
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952
00:49:24,880 --> 00:49:28,000
Speaker 1: where you'll also find an invitation to join our discord

953
00:49:28,080 --> 00:49:31,280
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954
00:49:31,560 --> 00:49:35,520
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955
00:49:35,560 --> 00:49:38,120
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