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Speaker 1: Hey, Daniel, do people still write us with questions? You know,

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Speaker 1: the inboxes overflowing like usual, overflowing? Don't you answer them?

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Speaker 1: I do, but every time I send a response, it

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Speaker 1: just seems to generate more questions. You're not giving them

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Speaker 1: a good answer. Maybe, but even when they say, oh,

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Speaker 1: now I get it, they always come back with but

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Speaker 1: that makes me wonder about something else. You should try

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Speaker 1: asking them a question you stopped them that might give

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Speaker 1: them something to think about, A question like would you

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Speaker 1: fund my research? Oh? Nobody will ride you back? Then

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Speaker 1: the question to end all questions? Literally, Hi am or

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Speaker 1: handmad cartoonist and the creator of PhD comments. Hi, I'm Daniel.

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Speaker 1: I'm a particle physicist and a professor at U c Irvine,

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Speaker 1: and I refuse to limit my chuckles. Are people trying

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Speaker 1: to limit your chuckles? Are you under the oppressive rule

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Speaker 1: of an anti chuckler? Well, we did have one person

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Speaker 1: who wrote in and complain about how much time I

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Speaker 1: spent chuckling on the podcast, and then we talked about

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Speaker 1: it on a recent episode, and then I got an

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Speaker 1: avalanche of emails from people who say, never stopped chuckling.

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Speaker 1: All right, there you go. You got some support from

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Speaker 1: the internet to keep chuckling. Somebody literally wrote to me

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Speaker 1: this morning and said, chuckle to your heart's content, sir.

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Speaker 1: So here I am chuckling away. It seems like a

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Speaker 1: bit of an overreaction over one comment from the internet.

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Speaker 1: It's suddenly turned into a social cause. Here free Daniel's chuckles. Now,

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Speaker 1: I'm self conscious about it. I don't know if I'm

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Speaker 1: chuckling on purpose, or chuckling to chuckle, or what's going on.

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Speaker 1: I got to get out of my own head. Oh man,

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Speaker 1: So they are being limited, they are shackled. Now. I

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Speaker 1: think maybe it's like a quantum thing. We just shouldn't

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Speaker 1: look at it so much and just let it be itself.

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Speaker 1: Let it be both annoying and endearing at this same time.

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Speaker 1: Stop trying to measure the chuckle and let it be

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Speaker 1: uncertain but welcome. For a podcast, Daniel and Jorge Explain

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Speaker 1: the Universe, a production of I Heart Radio in which

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Speaker 1: we do try to measure the universe, or at least

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Speaker 1: our understanding of it. Our goal is to use our

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Speaker 1: minds to try to nail down everything that's happening out

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Speaker 1: there in the universe from the tiniest little vibrating strings

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Speaker 1: that might make up the very fabric of reality, all

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Speaker 1: the way up to cosmic black holes that are swallowing

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Speaker 1: the centers of galaxies. We think it's a worthwhile way

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Speaker 1: to spend your time to try to understand the universe,

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Speaker 1: and we exult in the joy of our curiosity and

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Speaker 1: the chuckles that we find along the way. Yeah, because

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Speaker 1: it is a wonderful universe. It's huge, it's amazing, it's fascinating.

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Speaker 1: It gives us a lot to think about, and, as

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Speaker 1: you said, sometimes a lot to chuckle about. It's kind

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Speaker 1: of a funny universe. Funny smelling, funny looking, or funny weird.

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Speaker 1: It's got all the funnies. It's quantum in that way

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Speaker 1: as well. It's both funny ha ha and funny uh

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Speaker 1: at the same time. It's a superposition of funnies. It

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Speaker 1: is pretty funny weird, that's for sure. So many things

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Speaker 1: we have discovered about the universe that make us go,

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Speaker 1: what that can't possibly be true, And then we do

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Speaker 1: the experiment and the universe says, oh, yeah, that's exactly

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Speaker 1: what's going on, and it makes us reformulate the way

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Speaker 1: we think about the whole universe. For me, those are

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Speaker 1: the best moments in science, when the universe tells us

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Speaker 1: that we've been thinking about things the wrong way the

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Speaker 1: whole time. And science is how we explore the universe

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Speaker 1: and find out how things work and why they are

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Speaker 1: the way they are. And the way we do that

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Speaker 1: is with questions, right. Science is all based on questions.

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Speaker 1: Science is basically just people asking questions. You might imagine

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Speaker 1: that science is like some big building with columns where

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Speaker 1: information gets turned out on like a ticker tape or something,

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Speaker 1: But it's just a bunch of people being curious about

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Speaker 1: the universe. Every time you spend like nineteen seconds reading

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Speaker 1: about the life cycle of some guinea pig, it's because

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Speaker 1: some person has decided to devote their life to studying

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Speaker 1: that mee pig and how it spends its time. But

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Speaker 1: what you mean every time I spend nineteen seconds reading

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Speaker 1: about a guinea pig? Often do you spend nineteen seconds

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Speaker 1: reading about guinea pigs? Do I need to answer that question?

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Speaker 1: That's a question I don't want to answer to. I'm

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Speaker 1: not sure we want to go there. It's just a

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Speaker 1: hypothetical example. I want people to appreciate the time and

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Speaker 1: devotion that goes into every single scientific bit of knowledge

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Speaker 1: we have. Each one comes from some individual needing to

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Speaker 1: know the answer to that question. So science is in

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Speaker 1: the end, just a bunch of people asking questions and

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Speaker 1: deciding they got to know the answer, and then Daniel

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Speaker 1: deciding he's only going to spend nineteen seconds reading about

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Speaker 1: their lives work. Well, there is this amazing asymmetry right

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Speaker 1: in the same way you can spend decades doing research

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Speaker 1: and somebody can just like skim it on their phone

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Speaker 1: while they're in the bathroom and they go, oh, that's cool,

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Speaker 1: and then they move on with their lives. Right, But

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Speaker 1: think about the millions of people that could be reading

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Speaker 1: this on their phones. If you multiply I guess those

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Speaker 1: nineteen seconds of bathroom reading, you get, you know, millions

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Speaker 1: of seconds of bathroom reading. It's my goal as a

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Speaker 1: scientist is just to get maximum number of seconds of

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Speaker 1: bathroom or aim low, you know, just aim somewhere. Who

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Speaker 1: cares about Nobel prizes or citation counts or fancy awards

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Speaker 1: seconds of bathroom phone scrolling. That's my new metric. All right,

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Speaker 1: do you think academis should be based on that? Just

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Speaker 1: forget about you know, impact factors and h Indices and

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Speaker 1: Nobel Prices have a new award called the Toilets to Release.

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Speaker 1: I do think it's important that we reach everybody out there.

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Speaker 1: It's not important that they're on their toilet while we

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Speaker 1: reach them, But I do think it's vital that science

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Speaker 1: communicates outside of just academia and the rest of us scientists,

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Speaker 1: to everybody out there who's curious about the world and

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Speaker 1: who's helping to pay for our studies and pay our salaries.

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Speaker 1: This knowledge and this curiosity belongs to everyone, which is

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Speaker 1: why we did these episodes where we talk about questions

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Speaker 1: from not just from cutting edge scientists, but from people

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Speaker 1: out there like you. That's right, because science effects everybody,

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Speaker 1: and in fact, everybody has questions about the universe, maybe

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Speaker 1: not necessarily about guinea pigs or I'm sure people don't

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Speaker 1: think they have questions about guinea pig, but maybe they do,

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Speaker 1: and maybe they do have an ultimately question about how

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Speaker 1: life on nurse is here, why we're here, why is

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Speaker 1: the earth here, or what would it be like to

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Speaker 1: live in other planets? Are you saying there are people

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Speaker 1: out there who don't have questions about guinea pigs? Are

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Speaker 1: you serious? How many people do you know? Have you

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Speaker 1: met people outside of your little bubble there? It's just

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Speaker 1: so easy for your brain to generate guinea pig questions,

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Speaker 1: for example, how long would a guinea pig last on

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Speaker 1: the surface of the moon, or on guinea meat or

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Speaker 1: in outer space? Now you're sounding like a super villain.

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Speaker 1: I'm not suggesting we do these experiments, but I would

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Speaker 1: like to know the answer that people do have questions,

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Speaker 1: and sometimes we answer them here on the podcast. That's right.

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Speaker 1: If you have a question about something that doesn't make

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Speaker 1: sense to you, or maybe you heard us talk about

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Speaker 1: something on the podcast and it doesn't quite click in

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Speaker 1: your brain, or you were just line in your back

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Speaker 1: staring up at the stars and wondering what's going on

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Speaker 1: at the heart of them? Right to us two questions.

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Speaker 1: At Daniel and Jorge dot com, we answer every single

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Speaker 1: email and tweet, and we will answer your question as well. Wait, Daniel,

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Speaker 1: you don't answer all of my emails answer all emails

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Speaker 1: from listeners. Absolutely, do you listen to our podcast? I

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Speaker 1: do listen to the podcast. Maybe I just need to

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Speaker 1: frame it in the form of a physics question. There

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Speaker 1: you go. But people do send questions to us and

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Speaker 1: we answer them here. And so today we have three

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Speaker 1: great questions from listeners about exciting topics like what's it

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Speaker 1: like to live in a moon of Jupiter? Question about

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Speaker 1: black holes and whether they have a surface, and also

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Speaker 1: a question about math, which I guess maybe it's not

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Speaker 1: as exciting as the first two. What if it's about

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Speaker 1: guinea pig math? Would that make you more or less interested?

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Speaker 1: Does that mean like a trial math for the universe? No,

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Speaker 1: it is an exciting question. Also, it's about the very

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Speaker 1: nature of reality and whether reality is based on that,

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Speaker 1: And so it's tackled this first question first, and this

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Speaker 1: one comes from Billy. Hey, guys, I'm wondering what life

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Speaker 1: would be like for humans on the moon of a

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Speaker 1: gas giant. So suppose we find a Jupiter like system

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Speaker 1: within what we currently understand as the habitable zone of

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Speaker 1: a star. In this system is a moon that could

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Speaker 1: sustain human life. What would the day night cycle look

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Speaker 1: like with the planet or other moons blocking the Sun?

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Speaker 1: What kind of seasons would you go through with the

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Speaker 1: passing of more or less massive moons disrupt gravity? And

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Speaker 1: interesting ways could one of those moons support smaller satellites

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Speaker 1: like Phobos and demos. M Thanks and I look forward

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Speaker 1: to hearing your answer. Awesome, Thank you, Billie. That's a

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Speaker 1: great question, like what's it like? Because we often hear

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Speaker 1: about how the moons of other planets are maybe habitable,

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Speaker 1: and there are maybe like the size of the of Earth,

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Speaker 1: and sometimes they even have water, and so diggussion is like,

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Speaker 1: what would it be like to live in a moon

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Speaker 1: of another planet? It's a great question to put yourself

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Speaker 1: on the surface of one of those moons and think about,

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Speaker 1: like what would this guy look like? How long would

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Speaker 1: the day be, what would you see in this sky?

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Speaker 1: How many eclipses would there be, what would the seasons

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Speaker 1: be like. It's a really fun question, especially for example,

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Speaker 1: if you're writing a science fiction novel that's set on

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Speaker 1: one of those planets, as I suspect Billy might be, Well,

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Speaker 1: you're really suspicious here. Do you think Billy just has

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Speaker 1: an ulterior motive here? Can't you be asking out of

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Speaker 1: cheer curiosity? Absolutely, maybe he is and maybe he isn't.

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Speaker 1: But after we give our answer, I think he'll be

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Speaker 1: well set up to write that novel, and I'm looking

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Speaker 1: forward to reading it him and tens of thousands of

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Speaker 1: people where you get typing fast billy. But it is

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Speaker 1: an interesting question. What would it be like to live,

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Speaker 1: for example, in a moon like Europa, which is a

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Speaker 1: moon of Jupiter here in our solar system, which has

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Speaker 1: water and it's it's sort of inhabitable soon, right, Yeah,

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Speaker 1: and these moons are huge. Remember that Jupiter is much

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Speaker 1: much bigger than Earth, and so a moon of Jupiter

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Speaker 1: can be basically the size of a planet. Yeah. And

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Speaker 1: Europe in particular has liquid water in it, right, Europa

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Speaker 1: has an icy crust and we think oceans of liquid

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Speaker 1: water underneath. We're sending probes up there to sample those

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Speaker 1: oceans because sometimes they crack and shoot geysers of crystallized

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Speaker 1: water own into space, and we're gonna try to send

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Speaker 1: something through one of those plumes and see like is

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Speaker 1: their organic material in there, maybe little frozen microbes. It's

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Speaker 1: going to be pretty exciting. Yeah, And I think people

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Speaker 1: have also talked about Titan, right, which is another moon

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Speaker 1: in here in our solar system that might be livable. Yeah.

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Speaker 1: A lot of these moons are pretty big and pretty

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Speaker 1: rocky and might have liquid under the surface, so they

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Speaker 1: might like naturally have their own life. It's a great

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Speaker 1: way to ask the question like how likely is life

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Speaker 1: to evolve? Because it's like an independent way to sample

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Speaker 1: whether life emerges from similar conditions to what we have

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Speaker 1: on Earth. And there's another question, which is like, what

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Speaker 1: would it be like for us if we try to

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Speaker 1: colonize these places and actually established bases there. What would

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Speaker 1: your daily life be like on those surfaces? Yeah, and

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Speaker 1: I guess that's the question Billy had because I guess

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Speaker 1: if you're in a moon, then you're orbiting another planet,

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Speaker 1: and then that planet is presumably orbiting the Sun of

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Speaker 1: its solar system. And so the question is would that

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Speaker 1: make your days and nights super wonky and unpredictable or

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Speaker 1: would they make them maybe more predictable, or would you

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Speaker 1: even have seasons? Things like seasons. Yeah, it wouldn't make

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Speaker 1: it less predictable, but it would make it very, very

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Speaker 1: different from our experience. Earth. For example, currently just orbits

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Speaker 1: the Sun and we have a day night cycle because

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Speaker 1: of the Earth's spin. If your moon around Jupiter, for example,

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Speaker 1: then what determines whether you're seeing the Sun or not.

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Speaker 1: It's not your spin, but how long it takes you

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Speaker 1: to go around Jupiter. Wait, what do you mean Why

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Speaker 1: is it determined by your orbit around Jupiter. Wouldn't it

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Speaker 1: also depend on your inherent spin of the moon. There's

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Speaker 1: a couple of reasons. One the reason is Jupiter is huge,

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Speaker 1: and so it's going to eclipse the Sun pretty often.

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Speaker 1: Right half the time, You're gonna have Jupiter between you

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Speaker 1: and the Sun, and so because Jupiter is so big

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Speaker 1: in your sky, you can have like hours long eclipses

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Speaker 1: every day. Okay, maybe, um, let's get down to specifics,

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Speaker 1: like if I was in a moon of Jupiter, what

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Speaker 1: should I expect to see in terms of day and night?

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Speaker 1: How often would I see the Sun? One key thing

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Speaker 1: to understand is that these moons tend to be tidally locked,

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Speaker 1: meaning that one side of them faces Jupiter and one

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Speaker 1: side of them doesn't, just the way that like our

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Speaker 1: moon faces the Earth. So there's the near side of

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Speaker 1: the Moon and the far side of the Moon. We

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Speaker 1: always see the same side of the Moon from Earth.

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Speaker 1: But that doesn't necessarily mean that you're sort of going

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Speaker 1: around the Earth at the same rate that the Earth

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Speaker 1: is spinning, Like the Moon has a certain period around

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Speaker 1: the Earth, but the Earth is also spinning. So it

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Speaker 1: gets kind of complicated right, that's right. The Moon sees

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Speaker 1: different parts of the Earth, right, but the Earth always

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Speaker 1: sees the same side of the Moon. But now put

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Speaker 1: yourself on the Earth sized moon around Jupiter. It takes

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Speaker 1: like eighty five hours for Europa, for example, to go

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Speaker 1: around Jupiter. So now your day night cycle is determined

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Speaker 1: by how long it takes you to go around Jupiter. Okay,

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Speaker 1: so like if Jupiter was standing still, Europa would take

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Speaker 1: eighty five hours to go around to orbit around Jupiter.

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Speaker 1: That's what you're saying, Yeah, exactly. And so at any

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Speaker 1: given time, if it's on the side of Jupiter that's

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Speaker 1: facing the Sun, and the outward facing side of the

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Speaker 1: moon of Jupiter would see the sun, but the inner

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Speaker 1: part of this, the part of the moon that's facing Jupiter,

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Speaker 1: would not see the sun. Yeah, so you have like

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Speaker 1: two important hemispheres. You have the far side of Europa,

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Speaker 1: the one that's facing away from Jupiter, and the inner

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Speaker 1: side of the one that's facing towards Jupiter on the

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Speaker 1: far side, the outer side, that part never sees Jupiter.

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Speaker 1: Jupiter never appears in the sky on the far side

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Speaker 1: of Europa. But you do have eighty five hour long

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Speaker 1: day night cycles. So you have like forty two hours

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Speaker 1: of sunlight and then forty two hours of darkness. And

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Speaker 1: that's a big difference from what we have here. Right,

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Speaker 1: we have twenty four hour long periods which are determined

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Speaker 1: by the spin of the Earth. On Europa, the day

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Speaker 1: night cycles to term by how long it takes to

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Speaker 1: go around Jupiter. And a longer day night cycle means

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Speaker 1: higher temperatures during the day and colder temperatures at night. Yeah,

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Speaker 1: you gotta pack a heavier sweater. I guess, But I

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Speaker 1: guess if you're on the outside of the outward facing

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Speaker 1: side of the Moon, then life would be pretty regular, right,

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Speaker 1: and be sort of like here, except just longer days. Yeah,

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Speaker 1: it would be here, just longer days. And it depends

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Speaker 1: on how close in your orbit. For example, gannymed it's

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Speaker 1: pure it is like a hundred and seventy hours, and

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Speaker 1: I owe its period is forty two hours. So it

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Speaker 1: depends how close you are to the gas giant. You

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Speaker 1: can have a much longer or a shorter day night cycle.

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Speaker 1: It depends on how long it takes to go around

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Speaker 1: the gas giant instead of how fast you spin. And

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Speaker 1: all of those moons are tidally locked to Jupiter, Like

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Speaker 1: they're all always facing the same way towards Jupiter. Yeah,

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Speaker 1: they are. Okay, So like half of the world or

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Speaker 1: half of Europa just sees the regular day night cycle,

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Speaker 1: and I guess also regular seasons, right, because then the

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Speaker 1: season is kind of depend on whether Jupiter is farther

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Speaker 1: or closer to the Sun. Yeah, the seasons depend on

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Speaker 1: the tilt of the planet, right, And so Earth's axis

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Speaker 1: of rotation is tilted relative to the Sun's for example,

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Speaker 1: so part of the year the northern hemisphere is closer

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Speaker 1: to the Sun, and the other part of the year

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Speaker 1: the southern hemisphere is closer to the Sun. If you

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Speaker 1: have no tilt, then you don't have seasons. Every part

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Speaker 1: of the year is the same. If you're on a

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Speaker 1: moon of a planet that's tidally locked to that planet,

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Speaker 1: then the moon's tilt is connected to the planet's tilt.

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Speaker 1: In the case of Jupiter, for example, the tilt is

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Speaker 1: actually pretty all It's only three degrees, much less than

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Speaker 1: Earth's tilt. So on Jupiter the seasons are more mild.

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Speaker 1: The winter and summer are not as dramatic. So if

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Speaker 1: you're on the XO moon of a planet that isn't

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Speaker 1: tilted very much, then you're not going to have seasons.

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Speaker 1: You could also imagine being on the moon of a

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Speaker 1: planet that it tilted more. I see, so the seasons,

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Speaker 1: for example in Europe, at least in our case where

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Speaker 1: there isn't a lot of tilt, the seasons would be

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Speaker 1: pretty mild or like not a lot of variations in

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Speaker 1: the seasons like we have here on Earth. But maybe

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Speaker 1: that you're saying that day and night cycle would be

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Speaker 1: pretty dramatic, like the days would be super hot and

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Speaker 1: the nights would be super cool. And if you're on

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Speaker 1: the inside surface of the Moon, the one that's always

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Speaker 1: facing Jupiter, then things are pretty dramatic because Jupiter would

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Speaker 1: be huge in your sky. For example, you're on Europa,

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Speaker 1: then Jupiter would be like twenty times as big in

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Speaker 1: the sky as our moon is here on Earth. It

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Speaker 1: would be a huge thing. You'd see it all the time.

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Speaker 1: Would be like a giant thing blocking your your view. Right,

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Speaker 1: you see Jupiter like a huge thing in the sky. Yeah,

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Speaker 1: And you would see eclipses basically every day, right, because

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Speaker 1: Jupiter would get between you and the Sun every single day,

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Speaker 1: and every time you get that eclipse, it will it

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Speaker 1: will look like night, right, because Jupiter castle sich a

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Speaker 1: huge shadow. Yeah, so you have this day night cycle,

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Speaker 1: but then on the inside surface of the Moon you

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Speaker 1: also have a daily eclipse, which is like a mini

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Speaker 1: night in the middle of your day. So like everybody

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Speaker 1: takes a siesta, sounds great, let's move to open And

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Speaker 1: if you think about it, also, how much you see

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Speaker 1: of Jupiter depends on its relationship to the Sun, the

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Speaker 1: same way that like our moon, either looks full in

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Speaker 1: the sky if the sun is shining straight on it,

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Speaker 1: or it can look dark if the sun is shining

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Speaker 1: on the other side of it. The same thing will

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Speaker 1: happen to Jupiter. You could have like a crescent Jupiter

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Speaker 1: or a full Jupiter. Right, it would be pretty dramatic.

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Speaker 1: And also probably Jupiter would be spinning, so you would

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Speaker 1: see different sides of it as well, like sometimes you

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Speaker 1: see the red eye, sometimes you wouldn't. It would be

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Speaker 1: pretty beautiful actually, because Jupiter is a gorgeous planet. It's

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Speaker 1: got so much texture on it. It's frankly a lot

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Speaker 1: better looking than our moon. Well, it depends on your taste,

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Speaker 1: I guess, But I guess we're saying that if you're

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Speaker 1: on the side of the Moon and Jupiter that's facing Jupiter.

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Speaker 1: Then you would basically like your day would be split

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Speaker 1: into too many days, kind of like you would see

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Speaker 1: the sunrise above your horizon, but then it would dip

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Speaker 1: behind Jupiter then when it come out of Jupiter, and

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Speaker 1: then it would sunset back to the horizon on the

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Speaker 1: other side, right, and the sunset could be pretty dramatic

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Speaker 1: as well. Right, you have like light bending around Jupiter.

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Speaker 1: You have like sunsetting behind Jupiter, which would be pretty

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Speaker 1: dramatic because then the sun is being filtered through the

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Speaker 1: Jovian atmosphere, which would be pretty cool. And at night

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Speaker 1: you might have a really dramatic auroras like the northern

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Speaker 1: lights and the Southern lights. Cool. So you would have

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Speaker 1: to sunsets and in two sunrises every day, yeah, exactly,

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Speaker 1: you'd have one over the horizon of your own moon

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Speaker 1: and one over the horizon of Jupiter. All right, Now,

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Speaker 1: this sort of depends a lot on like you said,

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Speaker 1: the tilt, but it is maybe a pretty typical example

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Speaker 1: if you have like a big gas giant and with moons, right, like,

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Speaker 1: if that was somewhere other in another solar system, the

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Speaker 1: like the probability is that the Moon will be tidally

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Speaker 1: locked to the giant planet. Right. Yeah, it depends a

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Speaker 1: little bit on how close it is. The closer moon

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Speaker 1: gas planet, the stronger this effect is. You can also

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Speaker 1: have more complex tidal relationships, like, for example, Mercury is

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Speaker 1: technically tidally locked to the Sun, but the same side

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Speaker 1: of Mercury doesn't face the Sun all the time. It's

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Speaker 1: a complicated three to spin orbit resonance where it does

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Speaker 1: like three flips every two times around the Sun. So

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Speaker 1: you can get even more complex relationships. But we do

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Speaker 1: expect in other solar systems to see gas giants near

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Speaker 1: the habitable zone. Like in our solar system we have

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Speaker 1: Jupiter and Saturn kind of far out compared to the Earth.

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Speaker 1: But in many other solar systems we see in telescopes

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Speaker 1: we see what we call hot Jupiter's big gas giants

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Speaker 1: much closer to the Sun than our gas giants. So

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Speaker 1: it's possible they have moons inhabitable zone. Yeah, and those

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Speaker 1: moons would see a pretty regular day and night pycho,

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Speaker 1: which might be an ingredient for life. Right, Like it's

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Speaker 1: things were totally chiotic. If your days and nights were

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Speaker 1: totally unpredictable. Maybe life wouldn't be able to thrive in

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Speaker 1: a place like that. Yeah, it would be really amazing

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Speaker 1: to see life develop in other cycles, Like what would

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Speaker 1: it be like to have a big night and a

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Speaker 1: mini night and how would that affect the development of

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Speaker 1: life and reproductive cycles. Be really amazing to see those

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Speaker 1: experiments play out in reality. Yeah, everyone would be like

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00:19:20,600 --> 00:19:23,280
Speaker 1: the Spanish were like, what you don't take siesta? Everybody

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Speaker 1: takes siesta, even the plants, even the guinea pigs or

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Speaker 1: I guess exo guinea pigs on that planet. Would they

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Speaker 1: still be called guinea pigs? Well, I think that answer

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Speaker 1: is a question. For Billy, life on an extra moon

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Speaker 1: of a gas giant in another solar system would be

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Speaker 1: most likely pretty regular. Now let's get to our next question,

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Speaker 1: and this one is about black holes and whether they

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Speaker 1: have a surface. So we'll get to that question, but

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Speaker 1: first let's take a quick break. Alright, we were answering

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Speaker 1: listener questions and we just answered one about what it's

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Speaker 1: like to live on a moon of a gas giant

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Speaker 1: in another solar system. This one has asked kind of

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Speaker 1: a similar question, almost and it comes from Bobby Pelod

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Speaker 1: annual Horge. My name is Bobby from Arizona. This question

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Speaker 1: comes to you is kind of a two part Could

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Speaker 1: a black hole have a surface in that if you

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Speaker 1: gathered enough materials, let's say iron at a thousand or

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Speaker 1: billions of times the mass of the sun, and it

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Speaker 1: became a black hole, would you be able to fall

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Speaker 1: in that hole hypothetically and stand on the surface of

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Speaker 1: that solid iron. Additionally, could this same black hole potentially

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Speaker 1: gather enough materials around it to spark fusion again within

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Speaker 1: the black hole? All right, A little bit of a

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Speaker 1: mind bending question here is can a black hole have

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Speaker 1: a surface inside of its event horizon? And could you

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Speaker 1: maybe like spark a sun inside of the hole? Man?

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Speaker 1: I love that image of a sun hidden inside a

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Speaker 1: black hole, like fusion burning away furiously pumping out photons

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Speaker 1: which are forever trapped by the black hole. So thank

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Speaker 1: you Bobby for this question. What do you think Bobby

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00:21:10,760 --> 00:21:13,320
Speaker 1: was thinking? I think Bobby, like many people, is wondering

430
00:21:13,480 --> 00:21:17,080
Speaker 1: what's going on inside a black hole? When stuff falls

431
00:21:17,160 --> 00:21:19,600
Speaker 1: inside a black hole, what happens to it, what does

432
00:21:19,600 --> 00:21:22,880
Speaker 1: it do? What is the structure of matter in there?

433
00:21:22,960 --> 00:21:25,720
Speaker 1: What kind of weird stuff does it form. I think

434
00:21:25,760 --> 00:21:27,840
Speaker 1: that's sort of the heart of his question, and that's

435
00:21:27,840 --> 00:21:31,880
Speaker 1: a question that many people have, including black hole experts

436
00:21:31,920 --> 00:21:36,720
Speaker 1: and cosmologists and astronomers. Basically everybody wants to know what's

437
00:21:36,760 --> 00:21:39,080
Speaker 1: going on inside a black hole. All right, well, let

438
00:21:39,119 --> 00:21:41,920
Speaker 1: maybe let's dig into this and let's be maybe clear,

439
00:21:41,960 --> 00:21:44,159
Speaker 1: because black holes do kind of have a surface to them, right,

440
00:21:44,160 --> 00:21:45,960
Speaker 1: They have an edge to them, which is kind of

441
00:21:46,000 --> 00:21:48,720
Speaker 1: like the where the black starts. Basically, there's definitely like

442
00:21:48,720 --> 00:21:51,120
Speaker 1: an edge to a black hole in the sense that

443
00:21:51,200 --> 00:21:53,480
Speaker 1: we can say there's a point of no return. If

444
00:21:53,480 --> 00:21:56,560
Speaker 1: you get closer to the black hole than this, then

445
00:21:56,600 --> 00:22:00,520
Speaker 1: all paths lead towards the center. There's no escape, right.

446
00:22:00,600 --> 00:22:03,080
Speaker 1: That's what we call the event horizon. It's like a threshold,

447
00:22:03,160 --> 00:22:05,160
Speaker 1: but it's not a surface in the sense that it's

448
00:22:05,200 --> 00:22:08,879
Speaker 1: like a physical boundary. If you're falling into the black hole,

449
00:22:09,280 --> 00:22:12,760
Speaker 1: you don't necessarily even notice when you pass the event horizon.

450
00:22:12,920 --> 00:22:15,960
Speaker 1: There's no like gatekeeper there or force field or anything.

451
00:22:16,280 --> 00:22:20,080
Speaker 1: You can't even necessarily know whether you're past the event horizon.

452
00:22:20,119 --> 00:22:21,640
Speaker 1: The only way to know if you're past the event

453
00:22:21,680 --> 00:22:24,680
Speaker 1: horizon is to do the calculations and see if there's

454
00:22:24,720 --> 00:22:28,600
Speaker 1: any path out for any particle, even into the infinite future.

455
00:22:28,720 --> 00:22:30,560
Speaker 1: So there is this distance from the center of the

456
00:22:30,560 --> 00:22:33,360
Speaker 1: black hole we call the event horizon. That doesn't necessarily

457
00:22:33,359 --> 00:22:35,720
Speaker 1: mean that that is a surface. It's a surface only

458
00:22:35,720 --> 00:22:38,360
Speaker 1: in sort of a mathematical sense, right. It's it's kind

459
00:22:38,359 --> 00:22:40,480
Speaker 1: of like you say, a boundary, but it is a

460
00:22:40,520 --> 00:22:45,280
Speaker 1: three dimensional boundary, which kind of makes it a fear. Technically, yes,

461
00:22:45,520 --> 00:22:48,200
Speaker 1: and that one that's the mathematical event horizon, but that's

462
00:22:48,200 --> 00:22:50,399
Speaker 1: not necessarily what we see when we look at pictures

463
00:22:50,440 --> 00:22:53,240
Speaker 1: of a black hole. That's not necessarily like the black

464
00:22:53,520 --> 00:22:56,080
Speaker 1: that we see in those pictures, right, That one's bigger

465
00:22:56,119 --> 00:22:58,600
Speaker 1: than this event horizon, But that is that does sort

466
00:22:58,640 --> 00:23:01,040
Speaker 1: of look like a surface. Yeah, you're used to looking

467
00:23:01,080 --> 00:23:04,440
Speaker 1: at something and seeing it the way it is because

468
00:23:04,520 --> 00:23:07,640
Speaker 1: your mind is used to reconstructing objects in front of you,

469
00:23:07,880 --> 00:23:10,720
Speaker 1: assuming that light travels in straight lines, which is why

470
00:23:10,760 --> 00:23:12,879
Speaker 1: your mind gets confused. If you're looking at like a

471
00:23:12,920 --> 00:23:16,600
Speaker 1: bendy mirror or through some lenses, things look distorted, right,

472
00:23:16,920 --> 00:23:21,080
Speaker 1: in the same way, space itself is distorted even outside

473
00:23:21,119 --> 00:23:24,000
Speaker 1: the black hole, and light doesn't travel in straight lines.

474
00:23:24,040 --> 00:23:26,359
Speaker 1: It gets all twisted and bent. So what you see

475
00:23:26,400 --> 00:23:29,280
Speaker 1: when you look at a black hole is not the

476
00:23:29,359 --> 00:23:32,280
Speaker 1: actual physical extent of the black hole, but an image

477
00:23:32,320 --> 00:23:35,159
Speaker 1: of the black hole that's been distorted by these weird

478
00:23:35,200 --> 00:23:38,200
Speaker 1: paths that light follows. So specifically, you see a black

479
00:23:38,200 --> 00:23:41,960
Speaker 1: circle that's actually larger than the event horizon and includes

480
00:23:42,000 --> 00:23:44,159
Speaker 1: not just the part of the event horizon that's facing you,

481
00:23:44,240 --> 00:23:47,560
Speaker 1: but also the part from behind. Like photons that leave

482
00:23:47,600 --> 00:23:50,000
Speaker 1: the event horizon from behind the black hole get bent

483
00:23:50,080 --> 00:23:52,480
Speaker 1: around by the gravity and then back towards your eye,

484
00:23:52,760 --> 00:23:55,200
Speaker 1: so you can see the entire surface of the black

485
00:23:55,200 --> 00:23:57,800
Speaker 1: hole from any side of it, right, So, and that

486
00:23:57,920 --> 00:24:00,119
Speaker 1: sort of counts as a surface, right. You said the

487
00:24:00,119 --> 00:24:02,560
Speaker 1: word surface in the sense that maybe you wouldn't be

488
00:24:02,560 --> 00:24:04,600
Speaker 1: able to tell us you're falling in, but maybe somebody

489
00:24:04,640 --> 00:24:06,879
Speaker 1: from the outside would see you sort of fall into

490
00:24:06,920 --> 00:24:09,560
Speaker 1: that surface, right where they would see a surface relative

491
00:24:09,600 --> 00:24:12,400
Speaker 1: to somebody falling in. Yeah, it's definitely a boundary. It's

492
00:24:12,400 --> 00:24:14,800
Speaker 1: a surface mathematically, it's not a surface in the sense

493
00:24:14,840 --> 00:24:16,800
Speaker 1: that you could like stand on it. There's nothing there

494
00:24:16,800 --> 00:24:19,679
Speaker 1: to support you. You can't like walk around on the

495
00:24:19,720 --> 00:24:22,880
Speaker 1: event horizon. Right. So, I think Bobby's question now here

496
00:24:23,080 --> 00:24:25,760
Speaker 1: is whether or not a black hole has a surface

497
00:24:25,840 --> 00:24:29,080
Speaker 1: in the sense of like having a physical hard surface

498
00:24:29,119 --> 00:24:31,520
Speaker 1: on which you can actually like stand or into which

499
00:24:31,520 --> 00:24:34,000
Speaker 1: you would crash if you fell into a black hole.

500
00:24:34,000 --> 00:24:36,640
Speaker 1: Because I imagine maybe he's thinking, like a regular hole

501
00:24:36,680 --> 00:24:38,320
Speaker 1: here on the ground on Earth. It's a hole, and

502
00:24:38,320 --> 00:24:40,520
Speaker 1: you would fall in, but eventually you would hit something.

503
00:24:40,560 --> 00:24:42,159
Speaker 1: And if there's a whole bunch of stuff in the

504
00:24:42,160 --> 00:24:44,520
Speaker 1: hole you or like like a trash or something, you

505
00:24:44,520 --> 00:24:46,960
Speaker 1: would eventually fall into the hole, but then you would

506
00:24:47,040 --> 00:24:49,560
Speaker 1: hit the pile of trash. And so I think maybe

507
00:24:49,560 --> 00:24:51,760
Speaker 1: Bobby is wondering, like, you know, the black holes have

508
00:24:51,800 --> 00:24:53,520
Speaker 1: all this stuff inside of him. If you fell into

509
00:24:53,560 --> 00:24:56,320
Speaker 1: the black hole, wouldn't you eventually hit this stuff? Yeah,

510
00:24:56,440 --> 00:24:58,359
Speaker 1: And it's a great question when you think about this

511
00:24:58,440 --> 00:25:01,119
Speaker 1: is in terms of the forces. So gravity is very

512
00:25:01,200 --> 00:25:04,679
Speaker 1: powerful when things get very massive and things get very close,

513
00:25:04,800 --> 00:25:07,320
Speaker 1: but it's not all powerful, right, Like think about the

514
00:25:07,400 --> 00:25:10,160
Speaker 1: huge ball of iron in the center of the Earth.

515
00:25:10,600 --> 00:25:13,000
Speaker 1: Why isn't that a black hole. It's not a black

516
00:25:13,000 --> 00:25:16,560
Speaker 1: hole because iron has internal structure, has enough internal structure

517
00:25:16,600 --> 00:25:20,760
Speaker 1: to resist the gravitational collapse, like the atoms pushing against

518
00:25:20,840 --> 00:25:24,480
Speaker 1: each other that form this ball of iron, they resist gravity.

519
00:25:24,560 --> 00:25:27,960
Speaker 1: But inside a black hole, gravity is much much more powerful.

520
00:25:28,000 --> 00:25:30,880
Speaker 1: It's more powerful than the structure of iron. It's more

521
00:25:30,920 --> 00:25:34,000
Speaker 1: powerful than any sort of bond that we are aware of.

522
00:25:34,280 --> 00:25:36,879
Speaker 1: We don't think there's anything that can overcome the power

523
00:25:36,920 --> 00:25:39,879
Speaker 1: of gravity once you are inside the black hole. So

524
00:25:39,920 --> 00:25:41,920
Speaker 1: if you take a big blob of iron, as he said,

525
00:25:41,920 --> 00:25:44,679
Speaker 1: a huge mass of iron, like millions of times the

526
00:25:44,680 --> 00:25:46,680
Speaker 1: mass of the Sun, and collapse it to a black hole.

527
00:25:46,880 --> 00:25:49,040
Speaker 1: Once all that iron is inside the black hole, it

528
00:25:49,080 --> 00:25:53,159
Speaker 1: doesn't have the strength to resist the gravitational collapse. And

529
00:25:53,200 --> 00:25:56,840
Speaker 1: that's why general relativity predicts a singularity. It says that

530
00:25:56,880 --> 00:25:59,720
Speaker 1: things just keep compressing and compressing and compressing until you

531
00:25:59,760 --> 00:26:03,440
Speaker 1: get dot of infinite density. M hmmm. I think you're saying,

532
00:26:03,440 --> 00:26:05,399
Speaker 1: like here on Earth and there's a bunch of stuff

533
00:26:05,400 --> 00:26:08,280
Speaker 1: at the center, but it's not collapsing because other forces

534
00:26:08,320 --> 00:26:11,960
Speaker 1: are keeping gravity from collapsing further, you know, like the

535
00:26:12,000 --> 00:26:15,600
Speaker 1: electromagnetic force between all of the electrons and the protons

536
00:26:15,640 --> 00:26:17,960
Speaker 1: and the corks inside of the atoms in Earth's core.

537
00:26:18,359 --> 00:26:20,800
Speaker 1: But in a black hole, like we've sort of done

538
00:26:20,840 --> 00:26:23,879
Speaker 1: something different. We've like accumulated so much stuff that gravity

539
00:26:23,880 --> 00:26:27,840
Speaker 1: is so powerful it squishes even the electromagnetic force, like

540
00:26:27,920 --> 00:26:32,240
Speaker 1: it just squeezes everything down theoretically into an infinite point. Exactly.

541
00:26:32,320 --> 00:26:34,879
Speaker 1: You can have a certain mass of iron and you

542
00:26:34,920 --> 00:26:36,919
Speaker 1: can hold itself up, but if you make it too massive,

543
00:26:37,000 --> 00:26:40,120
Speaker 1: gravity gets too strong and then it collapses. And that's

544
00:26:40,119 --> 00:26:43,160
Speaker 1: how black holes form. Right. Black holes form from stars

545
00:26:43,200 --> 00:26:46,080
Speaker 1: that made too much heavy stuff at their core, so

546
00:26:46,119 --> 00:26:49,520
Speaker 1: they're no longer able to resist gravity's collapse, and then

547
00:26:49,560 --> 00:26:52,199
Speaker 1: it turns into a black hole. So all that iron,

548
00:26:52,400 --> 00:26:56,000
Speaker 1: according to general relativity, forms a singularity, a dot at

549
00:26:56,040 --> 00:26:58,080
Speaker 1: the center of the black hole where all of that

550
00:26:58,119 --> 00:27:01,159
Speaker 1: mass has accumulated. And so unless you can walk around

551
00:27:01,160 --> 00:27:04,439
Speaker 1: on an infinitesimal point, according to general relativity, there's not

552
00:27:04,480 --> 00:27:07,040
Speaker 1: really a surface inside the black hole, and there's no

553
00:27:07,119 --> 00:27:10,080
Speaker 1: chemistry going on and no fusion or no anything else. Right,

554
00:27:10,440 --> 00:27:11,960
Speaker 1: are you saying, at the center of a black hole,

555
00:27:12,000 --> 00:27:14,800
Speaker 1: there's no surface, there's no pile of trash or iron,

556
00:27:14,920 --> 00:27:18,400
Speaker 1: there's just an infinite dot. But what about the stuff

557
00:27:18,440 --> 00:27:22,080
Speaker 1: getting to the dot? Isn't that stuff accumulated? Maybe? Yeah,

558
00:27:22,119 --> 00:27:24,000
Speaker 1: that's a good point. It takes a finite amount of

559
00:27:24,040 --> 00:27:27,840
Speaker 1: time once you pass the event horizon to reach the singularity.

560
00:27:27,920 --> 00:27:30,320
Speaker 1: And so if the black hole is actively feeding, then

561
00:27:30,359 --> 00:27:33,800
Speaker 1: you have singularity surrounded by stuff that's still falling in,

562
00:27:34,240 --> 00:27:36,000
Speaker 1: you know, sort of like a toilet bowl of stuff

563
00:27:36,040 --> 00:27:39,639
Speaker 1: swirling around it. And remember this is according to general relativity.

564
00:27:39,760 --> 00:27:43,960
Speaker 1: Einstein's equations predict this runaway effect that leads to a collapse,

565
00:27:44,000 --> 00:27:46,639
Speaker 1: that leads to a point because in Einstein's theory, space

566
00:27:46,720 --> 00:27:49,880
Speaker 1: is smooth and continuous, it can be chopped up into

567
00:27:49,920 --> 00:27:53,320
Speaker 1: infinitely small slices, and you can also know where everything

568
00:27:53,480 --> 00:27:57,119
Speaker 1: is at all times. These assumptions are in total contradiction

569
00:27:57,160 --> 00:27:59,920
Speaker 1: to what we know about the universe being quantum mechanical,

570
00:28:00,240 --> 00:28:03,640
Speaker 1: and so physicists don't take this prediction of singularity seriously.

571
00:28:03,720 --> 00:28:05,760
Speaker 1: We don't see it as like an actual prediction of

572
00:28:05,800 --> 00:28:09,040
Speaker 1: what's happening inside. It's sort of like an indication that

573
00:28:09,080 --> 00:28:12,040
Speaker 1: the theory itself is breaking down because it predicts something

574
00:28:12,320 --> 00:28:15,879
Speaker 1: kind of crazy, right, physicist, something that maybe general relativity

575
00:28:15,920 --> 00:28:18,439
Speaker 1: is wrong, and you wouldn't get a singularity at the

576
00:28:18,680 --> 00:28:20,480
Speaker 1: center of a black hole. You would maybe get like

577
00:28:20,520 --> 00:28:23,800
Speaker 1: a quantum blob. Yeah, we think that something will prevent

578
00:28:23,800 --> 00:28:26,520
Speaker 1: the singularity from happening, because you can't confine particles to

579
00:28:26,520 --> 00:28:30,040
Speaker 1: an infinitely solved space without giving them effectively infinite energy

580
00:28:30,119 --> 00:28:32,480
Speaker 1: because of the quantum uncertainty principle, and so there's a

581
00:28:32,480 --> 00:28:36,040
Speaker 1: minimum quantum fuzz to the universe always. So when you

582
00:28:36,080 --> 00:28:39,080
Speaker 1: try to compress matter really, really far, there must be

583
00:28:39,200 --> 00:28:43,120
Speaker 1: some quantum mechanical way that they resist becoming a singularity,

584
00:28:43,200 --> 00:28:44,400
Speaker 1: you know. I think of them as sort of like

585
00:28:44,640 --> 00:28:48,200
Speaker 1: layers of defense. Matter has many ways to protect itself

586
00:28:48,240 --> 00:28:51,560
Speaker 1: from collapsing. First, there's like the chemical internal structure like

587
00:28:51,600 --> 00:28:53,840
Speaker 1: the Earth, or if you have a star, then it's fusion,

588
00:28:53,880 --> 00:28:56,720
Speaker 1: which is pushing out and pumping out energy to prevent collapse.

589
00:28:56,960 --> 00:28:58,800
Speaker 1: If you're like a neutron star, then there's like the

590
00:28:58,840 --> 00:29:01,480
Speaker 1: neutron degeneracy. We don't know what's going on inside a

591
00:29:01,520 --> 00:29:04,680
Speaker 1: black hole. There might be something else quantum mechanical that

592
00:29:04,800 --> 00:29:08,800
Speaker 1: matter can do to resist being compressed into a singularity.

593
00:29:08,880 --> 00:29:10,400
Speaker 1: To know how that works, we'd have to have a

594
00:29:10,480 --> 00:29:13,600
Speaker 1: theory of quantum gravity, which we just don't have that.

595
00:29:13,720 --> 00:29:16,320
Speaker 1: There's lots of fun ideas about what might be going

596
00:29:16,360 --> 00:29:19,240
Speaker 1: on inside. Yeah, and so inside of a black hole

597
00:29:19,280 --> 00:29:21,440
Speaker 1: there might not actually be a hole. I think it's

598
00:29:21,480 --> 00:29:23,200
Speaker 1: what you're saying, or it would still be a hole.

599
00:29:23,240 --> 00:29:26,000
Speaker 1: There just wouldn't be a pinpoint singularity in the middle.

600
00:29:26,040 --> 00:29:27,920
Speaker 1: And it might be that the stuff inside of the

601
00:29:27,960 --> 00:29:32,480
Speaker 1: hole is still holding together or you know, making a pile,

602
00:29:32,640 --> 00:29:35,760
Speaker 1: due to some other quantum force. Yeah, and it's very

603
00:29:35,840 --> 00:29:38,360
Speaker 1: unlikely that if you throw a bunch of iron into

604
00:29:38,400 --> 00:29:41,200
Speaker 1: a black hole that it's going to stay iron. It's

605
00:29:41,200 --> 00:29:44,000
Speaker 1: going to turn into some other completely different state of

606
00:29:44,120 --> 00:29:46,600
Speaker 1: matter because the iron molecules are not going to be

607
00:29:46,640 --> 00:29:49,520
Speaker 1: able to survive that intense experience. They're gonna get shredded

608
00:29:49,560 --> 00:29:52,560
Speaker 1: apart to their basic constituents. Maybe even the protons will

609
00:29:52,600 --> 00:29:55,360
Speaker 1: get pulled apart into their quarks. Maybe those quarks we

610
00:29:55,440 --> 00:29:58,000
Speaker 1: have pulled apart into whatever they are made out of.

611
00:29:58,400 --> 00:30:01,120
Speaker 1: We just don't know. From outside, it still just looks

612
00:30:01,120 --> 00:30:03,720
Speaker 1: like a black hole. You can't see beyond the event horizon.

613
00:30:04,240 --> 00:30:08,320
Speaker 1: So gravitationally speaking, a singularity or a quantum blob with

614
00:30:08,360 --> 00:30:10,960
Speaker 1: the same mass all acts the same from the outside,

615
00:30:10,960 --> 00:30:13,400
Speaker 1: So as you say, it still looks like a hole. Yeah,

616
00:30:13,520 --> 00:30:16,000
Speaker 1: But to Bobby's question, then if there is a quantum

617
00:30:16,040 --> 00:30:19,200
Speaker 1: flows ball in the middle, that means that the inside

618
00:30:19,200 --> 00:30:21,120
Speaker 1: of a black hole there would be a surface, right,

619
00:30:21,240 --> 00:30:23,880
Speaker 1: like a physical surface that you could maybe stand on,

620
00:30:24,000 --> 00:30:27,800
Speaker 1: if you could somehow survive or even think inside of

621
00:30:27,840 --> 00:30:30,440
Speaker 1: a black hole, right, Yeah, perhaps it depends a lot

622
00:30:30,600 --> 00:30:32,800
Speaker 1: on that theory of quantum gravity. So what's going on

623
00:30:32,840 --> 00:30:35,040
Speaker 1: inside it? You know, we talked to the podcast once

624
00:30:35,080 --> 00:30:38,160
Speaker 1: about the dark star theory that black holes are not

625
00:30:38,200 --> 00:30:42,320
Speaker 1: actually black holes. They're just very slowly collapsing stars that

626
00:30:42,360 --> 00:30:45,200
Speaker 1: will reach a minimum point from quantum mechanics and then

627
00:30:45,240 --> 00:30:48,520
Speaker 1: bounce back out and turn into like white holes eventually.

628
00:30:49,160 --> 00:30:51,160
Speaker 1: And so that's also not the kind of thing you'll

629
00:30:51,200 --> 00:30:54,480
Speaker 1: necessarily be able to walk around on a collapsing star

630
00:30:54,800 --> 00:30:57,560
Speaker 1: unless you have like really good boots. Yeah you have

631
00:30:57,640 --> 00:31:01,640
Speaker 1: dark Star shoes. But achnically it would have a surface, right,

632
00:31:01,640 --> 00:31:04,320
Speaker 1: It would answer Bobby's question, And the answer would be yes,

633
00:31:04,360 --> 00:31:06,880
Speaker 1: there would be like a physical blob inside of a

634
00:31:06,920 --> 00:31:09,800
Speaker 1: black hole, and that has a surface that you could

635
00:31:09,840 --> 00:31:12,400
Speaker 1: stand on or throw things at, and that they would

636
00:31:12,400 --> 00:31:14,520
Speaker 1: splat you stand on in sense that you could like

637
00:31:14,600 --> 00:31:16,360
Speaker 1: be there on top of it. I don't know if

638
00:31:16,360 --> 00:31:19,000
Speaker 1: he would absorb you or pull you apart or melt

639
00:31:19,040 --> 00:31:21,880
Speaker 1: you instantly, So I certainly wouldn't recommend it to anybody

640
00:31:21,920 --> 00:31:23,920
Speaker 1: out there who's considering it, It It sounds like people maybe

641
00:31:23,920 --> 00:31:25,680
Speaker 1: want to test it first, you know, by throwing like

642
00:31:26,560 --> 00:31:28,400
Speaker 1: an animal at it. What what kind of animal the

643
00:31:28,440 --> 00:31:33,920
Speaker 1: people usually do experiments with first? Is it bananas? Hamsters?

644
00:31:34,240 --> 00:31:39,640
Speaker 1: I can't remember bananas animals on other planets. Maybe exo

645
00:31:39,640 --> 00:31:42,560
Speaker 1: bananas might be in the animal category. Oh my goodness,

646
00:31:42,560 --> 00:31:45,440
Speaker 1: he'll bring up all kinds of ethical issues for me there.

647
00:31:45,520 --> 00:31:46,960
Speaker 1: Did I tell you, by the way, what my kids

648
00:31:47,040 --> 00:31:50,400
Speaker 1: dressed up as for Halloween? Well, my son has become

649
00:31:50,480 --> 00:31:52,440
Speaker 1: very long and lean, and so he dressed up as

650
00:31:52,600 --> 00:31:56,520
Speaker 1: a banana. All right, He's aspiring to the greatest fruit

651
00:31:56,560 --> 00:31:58,760
Speaker 1: on the planet. So we had a banana in the family.

652
00:31:59,080 --> 00:32:01,120
Speaker 1: But I'm not throwing him into any black holes no

653
00:32:01,120 --> 00:32:03,520
Speaker 1: matter what he wears on Halloween. Yeah, I might get

654
00:32:03,520 --> 00:32:06,200
Speaker 1: a little slippery, but I think that answers Bobby's question.

655
00:32:06,440 --> 00:32:09,120
Speaker 1: Could a black hole have a surface? The answer is yes.

656
00:32:09,720 --> 00:32:12,480
Speaker 1: I mean it has kind of a threshold surface. It

657
00:32:12,520 --> 00:32:16,240
Speaker 1: has a visual surface, which is the part that looks black,

658
00:32:16,280 --> 00:32:19,200
Speaker 1: and it may if general relativity is wrong, and we

659
00:32:19,240 --> 00:32:21,480
Speaker 1: think it most probably is, it does have maybe a

660
00:32:21,520 --> 00:32:24,760
Speaker 1: physical surface inside of the hole. It certainly might It

661
00:32:24,840 --> 00:32:27,280
Speaker 1: could be a dark star, it could be a fuzzball

662
00:32:27,400 --> 00:32:30,440
Speaker 1: made of strings, it could be something else entirely we

663
00:32:30,480 --> 00:32:33,280
Speaker 1: haven't yet imagined. If we could see inside a black hole,

664
00:32:33,360 --> 00:32:35,520
Speaker 1: we could know what happens when you compress matter in

665
00:32:35,560 --> 00:32:38,360
Speaker 1: these extreme circumstances, and we could learn something about the

666
00:32:38,400 --> 00:32:41,480
Speaker 1: fundamental nature of reality. All right, well, thank you Bobby

667
00:32:41,520 --> 00:32:44,240
Speaker 1: for that question, and now let's get to our last question.

668
00:32:44,400 --> 00:32:47,080
Speaker 1: This one's about the very nature of the universe and

669
00:32:47,120 --> 00:32:49,840
Speaker 1: whether or not it all adds up. So we'll tackle

670
00:32:49,880 --> 00:33:05,560
Speaker 1: that question. But first let's take another quick break. All right,

671
00:33:05,600 --> 00:33:08,240
Speaker 1: we were answering the listener questions, and our last question

672
00:33:08,520 --> 00:33:13,120
Speaker 1: is about the nature of reality. It comes from Matthew. Hello, Daniel,

673
00:33:13,160 --> 00:33:16,640
Speaker 1: and ho. I have a question about the math of

674
00:33:16,680 --> 00:33:23,280
Speaker 1: the universe. What is it? Trigonometry, algebra, calculus, the math

675
00:33:23,400 --> 00:33:27,240
Speaker 1: of space exploration. I was thinking about the James Web

676
00:33:27,280 --> 00:33:32,600
Speaker 1: space telescope out there in Lagrange too. How the heck

677
00:33:34,000 --> 00:33:38,040
Speaker 1: that was math? Right, Like somebody was like, oh, look,

678
00:33:38,080 --> 00:33:40,200
Speaker 1: here's the math. We can put this thing there and

679
00:33:40,240 --> 00:33:45,040
Speaker 1: it'll stay put because it's like circling the Sun with

680
00:33:45,200 --> 00:33:47,120
Speaker 1: the Earth and the Moon. But then it's like doing

681
00:33:47,160 --> 00:33:50,480
Speaker 1: little loop de loops in addition to the circling the sun.

682
00:33:51,720 --> 00:33:53,520
Speaker 1: And another thing, how do they get it to stay

683
00:33:53,600 --> 00:33:58,240
Speaker 1: focused on something a billion trillion miles away when it's

684
00:33:58,240 --> 00:34:02,400
Speaker 1: doing all that motion? Are they kind like firing thrusters? Anyways?

685
00:34:02,760 --> 00:34:06,160
Speaker 1: Tell me about the math of the universe, like from

686
00:34:06,200 --> 00:34:09,520
Speaker 1: the olden days to now? What the heck trigonometry? What

687
00:34:09,680 --> 00:34:13,279
Speaker 1: is it? Like that scene in Apollo thirteen where they'll

688
00:34:13,360 --> 00:34:17,279
Speaker 1: check their math and oh, my gosh, I gotta know more.

689
00:34:17,560 --> 00:34:20,520
Speaker 1: All right, thank you Matthew for that awesome question. Also,

690
00:34:20,600 --> 00:34:22,880
Speaker 1: I think, uh, I think that's my reaction to a

691
00:34:22,880 --> 00:34:25,080
Speaker 1: lot of these things about the universe. What the heck?

692
00:34:26,600 --> 00:34:29,120
Speaker 1: I can't? I can't anymore. It is amazing how the

693
00:34:29,200 --> 00:34:32,280
Speaker 1: universe works and how it seems to be so describable

694
00:34:32,320 --> 00:34:35,680
Speaker 1: by math. It really is incredible. Yeah, And so that's

695
00:34:35,960 --> 00:34:38,600
Speaker 1: Matthew's question, is that he's asking what is the math

696
00:34:38,920 --> 00:34:43,920
Speaker 1: up the universe? Is it trigonometry, algebra, calculus, long division?

697
00:34:44,200 --> 00:34:47,440
Speaker 1: It is really interesting to wonder which parts of math

698
00:34:47,640 --> 00:34:50,480
Speaker 1: describe the universe, because you can imagine that we could

699
00:34:50,560 --> 00:34:53,280
Speaker 1: invent a whole bunch of math that doesn't describe the universe,

700
00:34:53,320 --> 00:34:56,360
Speaker 1: that isn't relevant necessarily. What do you mean, Like, you

701
00:34:56,360 --> 00:34:58,600
Speaker 1: can have mathods as one plus one equals two of it,

702
00:34:58,680 --> 00:35:00,600
Speaker 1: but but maybe you could have a neverse where one

703
00:35:00,640 --> 00:35:02,520
Speaker 1: plus one doesn't equal to no. I mean that you

704
00:35:02,560 --> 00:35:05,560
Speaker 1: can invent kinds of math that don't have to reflect

705
00:35:05,600 --> 00:35:08,760
Speaker 1: the physical universe. For example, you can invent weird kinds

706
00:35:08,760 --> 00:35:12,800
Speaker 1: of geometry, you know, surfaces that live in eight dimensions,

707
00:35:12,800 --> 00:35:14,920
Speaker 1: but the universe might not be eight dimensionals. So you

708
00:35:14,920 --> 00:35:17,840
Speaker 1: can spend your whole life thinking about the mathematics of

709
00:35:17,880 --> 00:35:21,000
Speaker 1: eight dimensional objects, but that's not actually relevant to our

710
00:35:21,200 --> 00:35:24,200
Speaker 1: universe if our universe is just three dimensional. But you know,

711
00:35:24,320 --> 00:35:27,760
Speaker 1: we don't know how people spend, for example, decades developing

712
00:35:27,760 --> 00:35:31,319
Speaker 1: ideas called group theory about how things relate to each other,

713
00:35:31,520 --> 00:35:33,600
Speaker 1: then later it turns out to be totally relevant to

714
00:35:33,719 --> 00:35:36,040
Speaker 1: particle physics. So you never know what math is going

715
00:35:36,080 --> 00:35:39,080
Speaker 1: to be relevant. But it's definitely possible that there's kinds

716
00:35:39,080 --> 00:35:42,239
Speaker 1: of math which are not relevant to the universe, right.

717
00:35:42,239 --> 00:35:44,560
Speaker 1: But I guess it's kind of a tricky philosophical question

718
00:35:44,600 --> 00:35:47,160
Speaker 1: because like, if you can come up with math that

719
00:35:47,360 --> 00:35:51,480
Speaker 1: makes sense, doesn't technically mean that it exists in the universe.

720
00:35:51,880 --> 00:35:53,800
Speaker 1: Even if you can find like a you know, a

721
00:35:53,920 --> 00:35:57,160
Speaker 1: law of particles that follows that math. The maths is

722
00:35:57,160 --> 00:35:59,640
Speaker 1: still there and it makes sense in this universe. Doesn't

723
00:35:59,760 --> 00:36:01,960
Speaker 1: mean it it's part of the universe. Yeah, It's one

724
00:36:01,960 --> 00:36:04,640
Speaker 1: of the deepest questions in the philosophy of math, like

725
00:36:05,160 --> 00:36:08,240
Speaker 1: are those numbers real and the part of the universe?

726
00:36:08,880 --> 00:36:10,640
Speaker 1: And then you get into weird things like well, what

727
00:36:10,680 --> 00:36:12,920
Speaker 1: does it mean to be real? Because like those numbers,

728
00:36:13,200 --> 00:36:15,920
Speaker 1: the number two, where is the number two? Right? Everything

729
00:36:15,960 --> 00:36:18,880
Speaker 1: else that's real has like a location, it has behavior,

730
00:36:18,960 --> 00:36:22,440
Speaker 1: can participate in experiments. You can talk about whether protons

731
00:36:22,440 --> 00:36:24,360
Speaker 1: are real and you can do tests on them. You

732
00:36:24,360 --> 00:36:26,719
Speaker 1: can't do that for the number two. There's no way

733
00:36:26,880 --> 00:36:30,440
Speaker 1: the number two can like participate in experiments, can cause effects.

734
00:36:31,239 --> 00:36:33,520
Speaker 1: So if it's real, it's real in a different way

735
00:36:33,560 --> 00:36:35,919
Speaker 1: than other things that are real. But I think maybe

736
00:36:36,000 --> 00:36:39,640
Speaker 1: Matthew's question is not so much about these big philosophical questions.

737
00:36:39,719 --> 00:36:42,399
Speaker 1: I think maybe he's coming at it from a more

738
00:36:42,440 --> 00:36:44,759
Speaker 1: intuitive point of view, which is like, you know, does

739
00:36:44,840 --> 00:36:50,440
Speaker 1: the universe have a mathematical description? Can you describe the

740
00:36:50,520 --> 00:36:53,440
Speaker 1: universe with math? And if you can, what kind of

741
00:36:53,480 --> 00:36:56,120
Speaker 1: math is it? Is it trigonometry, algebra or is it

742
00:36:56,200 --> 00:37:00,279
Speaker 1: just all addition all the way down. Um. I would

743
00:37:00,320 --> 00:37:03,160
Speaker 1: say there's two parts of that answer. One is what

744
00:37:03,239 --> 00:37:05,680
Speaker 1: kind of math do we use to describe the universe?

745
00:37:06,239 --> 00:37:08,880
Speaker 1: And the other is whether we could boil that down

746
00:37:08,960 --> 00:37:11,200
Speaker 1: to one sort of like basic kind of math. So

747
00:37:11,280 --> 00:37:14,520
Speaker 1: on the first one, we tend to use calculus a lot.

748
00:37:14,840 --> 00:37:18,080
Speaker 1: Like calculus is often described as the language of physics,

749
00:37:18,080 --> 00:37:21,200
Speaker 1: it's really a very very powerful tool to describe what

750
00:37:21,239 --> 00:37:24,279
Speaker 1: we see about the universe. That's because calculus is like

751
00:37:24,360 --> 00:37:27,319
Speaker 1: the mathematics of change. If you have something flying through

752
00:37:27,360 --> 00:37:29,960
Speaker 1: the air with a certain velocity, that's fine. But now

753
00:37:30,000 --> 00:37:32,120
Speaker 1: if you want to change that's velocity and you want

754
00:37:32,120 --> 00:37:35,440
Speaker 1: to understand where it's gonna go, you have to accumulate

755
00:37:35,480 --> 00:37:38,160
Speaker 1: all those changes and figure out where it's going to land.

756
00:37:38,440 --> 00:37:42,680
Speaker 1: That requires calculus. So the mathematics of change is really

757
00:37:42,719 --> 00:37:46,239
Speaker 1: the mathematics of motion in our universe. So calculus is

758
00:37:46,280 --> 00:37:49,000
Speaker 1: really fundamental, right because we have you saying because we

759
00:37:49,040 --> 00:37:51,759
Speaker 1: have time and universe and time kind of implies change

760
00:37:51,800 --> 00:37:53,400
Speaker 1: and we need calculus. But it's also I think a

761
00:37:53,440 --> 00:37:57,360
Speaker 1: little bit maybe more fundamental, I wonder, because it calcula

762
00:37:57,440 --> 00:38:00,239
Speaker 1: is also about how the rates of change the pend

763
00:38:00,280 --> 00:38:03,280
Speaker 1: on each other, right, Like we seem to have found laws,

764
00:38:03,360 --> 00:38:05,719
Speaker 1: for example, like F equals m A that says that,

765
00:38:05,760 --> 00:38:09,000
Speaker 1: you know, the rate of change depends on this force

766
00:38:09,120 --> 00:38:12,440
Speaker 1: or that force or this situation, and so it seems

767
00:38:12,440 --> 00:38:16,759
Speaker 1: like the universe has laws that govern over the rate

768
00:38:16,800 --> 00:38:20,600
Speaker 1: of changes of things, and that's why calculus is useful. Yeah,

769
00:38:20,640 --> 00:38:23,239
Speaker 1: Calculus is useful because he gives us these tools, and

770
00:38:23,280 --> 00:38:25,600
Speaker 1: we can express the laws of the universe that we

771
00:38:25,640 --> 00:38:28,439
Speaker 1: discover in terms of those So you're right, almost all

772
00:38:28,520 --> 00:38:31,239
Speaker 1: the laws of physics, like F equals m A, that's

773
00:38:31,280 --> 00:38:35,160
Speaker 1: an expression in calculus, because a is a derivative. Acceleration

774
00:38:35,280 --> 00:38:38,400
Speaker 1: is the rate of change of velocity. That's a differential

775
00:38:38,560 --> 00:38:42,360
Speaker 1: that's part of calculus. Force is really change in momentum

776
00:38:42,440 --> 00:38:45,839
Speaker 1: with respect to time, right, and so that's a differential.

777
00:38:46,400 --> 00:38:48,400
Speaker 1: So you're absolutely right that most of the laws of

778
00:38:48,440 --> 00:38:51,600
Speaker 1: physics can be expressed in terms of objects that were

779
00:38:51,600 --> 00:38:54,839
Speaker 1: invented for calculus. But calculus also handles things that are

780
00:38:54,880 --> 00:38:57,680
Speaker 1: not rate of change with time. You know, calculus lets

781
00:38:57,719 --> 00:39:00,440
Speaker 1: you integrate over space. Also, if you have an object

782
00:39:00,520 --> 00:39:02,400
Speaker 1: that has like a varying density and you want to

783
00:39:02,400 --> 00:39:06,160
Speaker 1: know it's total mass. You can integrate over the object

784
00:39:06,440 --> 00:39:08,880
Speaker 1: over space in order to get the total mass if

785
00:39:08,880 --> 00:39:11,279
Speaker 1: the density is varying. So calculus is the math of

786
00:39:11,400 --> 00:39:14,200
Speaker 1: change of time or of space. Yeah, and then what

787
00:39:14,239 --> 00:39:16,439
Speaker 1: happens when you go down to the quantum level? First

788
00:39:16,480 --> 00:39:19,480
Speaker 1: of all, does calculus still apply or does it get

789
00:39:19,480 --> 00:39:23,280
Speaker 1: more into like quantum of waves and and functions and fields.

790
00:39:23,440 --> 00:39:26,399
Speaker 1: Is calculus still useful there and maybe even appropriate because

791
00:39:26,480 --> 00:39:29,600
Speaker 1: the world is quantized. It's absolutely still useful there. Like

792
00:39:29,600 --> 00:39:33,799
Speaker 1: the shorting your equation, that's a differential equation. Absolutely, it's

793
00:39:33,800 --> 00:39:36,000
Speaker 1: a wave equation which tells you how the wave changes

794
00:39:36,040 --> 00:39:38,320
Speaker 1: in space and how that relates to how it changes

795
00:39:38,360 --> 00:39:43,040
Speaker 1: in time. So calculus super fundamental, and the basic theory

796
00:39:43,120 --> 00:39:45,800
Speaker 1: of the standard model, which we call quantum field theory,

797
00:39:46,239 --> 00:39:49,440
Speaker 1: is full of calculus because calculus involves integrals, and integrals

798
00:39:49,440 --> 00:39:51,840
Speaker 1: allow you to add up over many, many different things.

799
00:39:52,200 --> 00:39:54,360
Speaker 1: You can add up slices in time or slices in

800
00:39:54,400 --> 00:39:57,239
Speaker 1: space a quantum mechanically, it also leads you add up

801
00:39:57,280 --> 00:40:01,360
Speaker 1: different probabilities. So, for example, one important formulation of quantum

802
00:40:01,360 --> 00:40:03,879
Speaker 1: mechanics by Feinneman says, if you want to understand how

803
00:40:03,880 --> 00:40:06,040
Speaker 1: a particle moves from A to B. You have to

804
00:40:06,239 --> 00:40:10,680
Speaker 1: integrate over all possible paths of the particle. So calculus

805
00:40:10,760 --> 00:40:15,800
Speaker 1: lest you consider multiple different possibilities simultaneously. So it's crucial

806
00:40:15,880 --> 00:40:19,120
Speaker 1: to quantum field theory. Right, So calculus is pretty useful,

807
00:40:19,239 --> 00:40:21,799
Speaker 1: So kids pay attention to that class when you when

808
00:40:21,840 --> 00:40:24,440
Speaker 1: you get to calculus. But I guess maybe a question

809
00:40:24,480 --> 00:40:28,560
Speaker 1: here is is calculus the theory to use for the university?

810
00:40:28,600 --> 00:40:30,879
Speaker 1: Like it's useful and you definitely seem to be able

811
00:40:30,920 --> 00:40:32,920
Speaker 1: to use it to describe a lot of the universe

812
00:40:32,920 --> 00:40:34,920
Speaker 1: and even predict a lot of what happens in the universe.

813
00:40:34,960 --> 00:40:37,520
Speaker 1: But maybe we're just kind of lucky, Like maybe calculus

814
00:40:37,719 --> 00:40:39,480
Speaker 1: just sort of works most of the time, and so

815
00:40:39,560 --> 00:40:41,480
Speaker 1: we think it's the way to go. But maybe there's

816
00:40:41,480 --> 00:40:43,760
Speaker 1: a different math the here that would describe the universe

817
00:40:43,760 --> 00:40:45,719
Speaker 1: in more detailed The more we learn about it, is

818
00:40:45,760 --> 00:40:49,319
Speaker 1: that possible? It certainly is possible, and we're constantly improving

819
00:40:49,360 --> 00:40:52,080
Speaker 1: on and developing new techniques in calculus. It's not like

820
00:40:52,120 --> 00:40:55,320
Speaker 1: calculus is a finished thing. It's not like Newton enliven.

821
00:40:55,400 --> 00:40:57,520
Speaker 1: It's invented a few and years ago and now it's done.

822
00:40:57,760 --> 00:41:00,600
Speaker 1: People are still working on it, like today, figuring out

823
00:41:00,640 --> 00:41:04,120
Speaker 1: ways to do complicated integrals and whole new techniques that

824
00:41:04,200 --> 00:41:08,520
Speaker 1: that makes previously unsolvable problems now solvable. So it's definitely

825
00:41:08,520 --> 00:41:11,479
Speaker 1: a developing field and it's improving, and so that means

826
00:41:11,480 --> 00:41:13,439
Speaker 1: that in the future we will have more powerful math

827
00:41:13,480 --> 00:41:16,680
Speaker 1: that describes the universe even better, because there's lots of

828
00:41:16,719 --> 00:41:19,760
Speaker 1: things that we still don't know how to do, problems

829
00:41:19,760 --> 00:41:22,080
Speaker 1: we can't solve, probably because we just don't have the

830
00:41:22,080 --> 00:41:25,600
Speaker 1: mathematical tools for them. Yet you're saying is pretty good

831
00:41:25,640 --> 00:41:28,399
Speaker 1: and we're going to stick with it, But maybe less

832
00:41:28,440 --> 00:41:31,319
Speaker 1: you were saying, the deeper question is whether or not

833
00:41:31,600 --> 00:41:34,920
Speaker 1: this is just in general, using math to describe the universe,

834
00:41:35,000 --> 00:41:37,960
Speaker 1: if that is something fundamental about the universe, or it's

835
00:41:38,000 --> 00:41:40,680
Speaker 1: just our way of understanding it. This is the question

836
00:41:40,680 --> 00:41:43,239
Speaker 1: the philosophers of math debate and have been debating for

837
00:41:43,440 --> 00:41:47,160
Speaker 1: thousands of years and probably will keep debating for thousands

838
00:41:47,239 --> 00:41:50,000
Speaker 1: more years. I'm not sure it's something they can really

839
00:41:50,080 --> 00:41:52,160
Speaker 1: make progress on that Really at the heart of it,

840
00:41:52,200 --> 00:41:55,319
Speaker 1: we're asking whether math describes the universe or whether it

841
00:41:55,360 --> 00:42:00,120
Speaker 1: controls the universe, Like is the universe itself mathematical. Is

842
00:42:00,160 --> 00:42:02,120
Speaker 1: math part of the universe itself or is it just

843
00:42:02,280 --> 00:42:05,160
Speaker 1: our description of it is the way that we organize

844
00:42:05,200 --> 00:42:08,080
Speaker 1: our thoughts. Is it like a convenient way to think,

845
00:42:08,480 --> 00:42:11,880
Speaker 1: or is it really the source code of the universe itself?

846
00:42:11,960 --> 00:42:14,640
Speaker 1: And telling the difference between those things is pretty tricky.

847
00:42:15,000 --> 00:42:17,400
Speaker 1: You mean, like the difference is kind of like whether

848
00:42:17,440 --> 00:42:20,960
Speaker 1: the universe actually cares about math, right, because maybe, like

849
00:42:20,960 --> 00:42:23,719
Speaker 1: in one scenario, the universe just does its thing and

850
00:42:23,920 --> 00:42:25,799
Speaker 1: the universe doesn't even care about math or know what

851
00:42:25,920 --> 00:42:28,880
Speaker 1: math is. The other scenario is that the universe is

852
00:42:28,960 --> 00:42:32,280
Speaker 1: kind of beholden to math or somehow the universe is

853
00:42:32,480 --> 00:42:35,120
Speaker 1: math at its core. That's the difference, right, Yeah, that's

854
00:42:35,120 --> 00:42:36,839
Speaker 1: a good way to think about it. Sometimes the way

855
00:42:36,840 --> 00:42:38,400
Speaker 1: I think about it is in terms of like a

856
00:42:38,440 --> 00:42:41,839
Speaker 1: computer program. Say somebody writes a computer program and then

857
00:42:41,880 --> 00:42:44,319
Speaker 1: you use it Microsoft Word for example, and you could

858
00:42:44,320 --> 00:42:46,719
Speaker 1: try to like figure out how word works, and you

859
00:42:46,719 --> 00:42:50,640
Speaker 1: could reverse engineering using some other programming language. Maybe it

860
00:42:50,719 --> 00:42:53,279
Speaker 1: was written in Python and you figured out how to

861
00:42:53,320 --> 00:42:55,840
Speaker 1: write it in C. Right now you have a description

862
00:42:55,880 --> 00:42:58,759
Speaker 1: of this computer program in your own language. That doesn't

863
00:42:58,760 --> 00:43:01,240
Speaker 1: necessarily mean that that's the per brand that's actually running

864
00:43:01,320 --> 00:43:03,879
Speaker 1: inside of word. You might just have a description of it,

865
00:43:04,080 --> 00:43:06,720
Speaker 1: or it might be that you've discovered the actual source

866
00:43:06,760 --> 00:43:09,319
Speaker 1: code ForWord itself. In the same way, the math that

867
00:43:09,360 --> 00:43:12,000
Speaker 1: we are building might be the actual code that the

868
00:43:12,120 --> 00:43:15,200
Speaker 1: universe is following. Or it could just be a good

869
00:43:15,239 --> 00:43:18,400
Speaker 1: description of it. And there might be other possible descriptions

870
00:43:18,400 --> 00:43:22,520
Speaker 1: that are equally valid. We just don't know, all right, Well,

871
00:43:22,560 --> 00:43:24,279
Speaker 1: which is it? Then? I guess I wish we knew.

872
00:43:24,280 --> 00:43:26,680
Speaker 1: One of my favorite philosophical attempts to answer this question

873
00:43:26,800 --> 00:43:29,879
Speaker 1: came from hartree Field. He said, let's see if it's

874
00:43:29,920 --> 00:43:34,479
Speaker 1: possible to do science and physics specifically without any math,

875
00:43:34,520 --> 00:43:38,800
Speaker 1: without any numbers at all, Like, can you devise laws

876
00:43:38,800 --> 00:43:42,120
Speaker 1: of physics that don't have numbers in them? Wait, numbers

877
00:43:42,280 --> 00:43:45,719
Speaker 1: or even like variables and symbols or none of that,

878
00:43:45,960 --> 00:43:48,200
Speaker 1: none of that at all, he writes in his book,

879
00:43:48,280 --> 00:43:52,640
Speaker 1: like I denied that numbers exist. He wrote this whole

880
00:43:52,640 --> 00:43:56,040
Speaker 1: book called Science Without Numbers where he was admitting that

881
00:43:56,120 --> 00:43:58,360
Speaker 1: math is useful, but he was trying to prove that

882
00:43:58,400 --> 00:44:01,759
Speaker 1: it's not necessary by building up a new version of

883
00:44:01,800 --> 00:44:05,240
Speaker 1: these theories that didn't use any numbers. What what would

884
00:44:05,280 --> 00:44:07,080
Speaker 1: that even look like if you wrote it down, that

885
00:44:07,200 --> 00:44:10,600
Speaker 1: you have to write down something. While on page forty

886
00:44:10,680 --> 00:44:13,959
Speaker 1: seven of his book without Numbers, for example, he talks

887
00:44:14,000 --> 00:44:17,200
Speaker 1: about how to do this. It's pretty philosophically intricate. He

888
00:44:17,320 --> 00:44:21,760
Speaker 1: like abuse points of space with certain kind of properties

889
00:44:22,160 --> 00:44:24,799
Speaker 1: so that you don't ever have to do any calculations.

890
00:44:24,800 --> 00:44:29,040
Speaker 1: Like most specifically he thinks about gravity and how gravity work,

891
00:44:29,120 --> 00:44:31,560
Speaker 1: and when we do gravitational calculations, we create all sort

892
00:44:31,560 --> 00:44:35,320
Speaker 1: of abstract intermediate ideas, like the gravitational field that we

893
00:44:35,360 --> 00:44:37,200
Speaker 1: say that the Earth is pulled on the Sun because

894
00:44:37,200 --> 00:44:39,879
Speaker 1: of the gravitational field of the Sun. And he's like,

895
00:44:40,120 --> 00:44:42,480
Speaker 1: you need numbers to describe that field, but what if

896
00:44:42,520 --> 00:44:46,040
Speaker 1: that field wasn't there. You don't ever observe the field directly,

897
00:44:46,080 --> 00:44:48,200
Speaker 1: You just observe the Sun pulling on the Earth. What

898
00:44:48,239 --> 00:44:51,080
Speaker 1: if that's just something that space does and there is

899
00:44:51,120 --> 00:44:53,839
Speaker 1: no field at all. That's an example of how he's

900
00:44:53,840 --> 00:44:57,520
Speaker 1: trying trying to rid the calculation of intermediate steps that

901
00:44:57,600 --> 00:45:00,640
Speaker 1: need numbers to describe them, but all tim redly would

902
00:45:00,640 --> 00:45:02,200
Speaker 1: and you have to write it down, And what do

903
00:45:02,280 --> 00:45:06,360
Speaker 1: you eventually have to you know, have an equation or

904
00:45:06,400 --> 00:45:09,960
Speaker 1: something you know in his formulation of Newton's gravity, there

905
00:45:10,000 --> 00:45:13,640
Speaker 1: are new equations, there are no numbers, there is no mathematics.

906
00:45:13,880 --> 00:45:16,120
Speaker 1: It's hard to imagine because we think that math is

907
00:45:16,160 --> 00:45:18,480
Speaker 1: the answer, right, Like you do a calculation, you get

908
00:45:18,480 --> 00:45:20,120
Speaker 1: a result, it says, oh, the force on the earth.

909
00:45:20,239 --> 00:45:23,239
Speaker 1: Is this for us? Math is the language itself. But

910
00:45:23,320 --> 00:45:25,520
Speaker 1: he developed a way to perform these calculations to think

911
00:45:25,560 --> 00:45:27,960
Speaker 1: about it that doesn't have math as the internal steps

912
00:45:28,040 --> 00:45:31,000
Speaker 1: or either as the answer. And is this credible? Does

913
00:45:31,040 --> 00:45:34,720
Speaker 1: this seem suspect or is this like an actual valid

914
00:45:35,200 --> 00:45:38,200
Speaker 1: possibility for the universe. I think that most philosophers see

915
00:45:38,200 --> 00:45:41,000
Speaker 1: its like a heroic effort to make the point that

916
00:45:41,120 --> 00:45:44,480
Speaker 1: maybe math isn't necessary. But there's a lot of steps

917
00:45:44,520 --> 00:45:46,799
Speaker 1: he took along the way which people quipple with. And

918
00:45:46,840 --> 00:45:49,200
Speaker 1: people don't think that this effort could be applied to

919
00:45:49,239 --> 00:45:52,960
Speaker 1: like everything in physics. And so it's like, hey, cool point, man,

920
00:45:53,480 --> 00:45:56,400
Speaker 1: But it doesn't really work. It doesn't really convince anybody

921
00:45:56,480 --> 00:45:59,359
Speaker 1: that you don't need math to do science. I see

922
00:45:59,360 --> 00:46:01,000
Speaker 1: people are like, hey, there are a number of errors

923
00:46:01,000 --> 00:46:02,759
Speaker 1: in your theory, and then he's like, wait, but there

924
00:46:02,760 --> 00:46:06,239
Speaker 1: are no numbers exactly. I think that most people, most

925
00:46:06,280 --> 00:46:09,160
Speaker 1: mathematicians and most physicists think that math is an inherent

926
00:46:09,280 --> 00:46:12,200
Speaker 1: part of the universe, right, But then I guess the

927
00:46:12,280 --> 00:46:15,000
Speaker 1: larger question I was kind of alluding to is whether

928
00:46:15,120 --> 00:46:17,560
Speaker 1: the universe cares if there's math or not, or like

929
00:46:17,560 --> 00:46:21,759
Speaker 1: which came first, math or physics. I don't know what

930
00:46:21,800 --> 00:46:24,400
Speaker 1: it means for the universe to care about something, but

931
00:46:24,440 --> 00:46:26,799
Speaker 1: I think there is another interesting aspect to Matthew's question,

932
00:46:26,840 --> 00:46:31,440
Speaker 1: which is, like which math is essential? Trigonometry, algebra, calculus.

933
00:46:31,840 --> 00:46:34,319
Speaker 1: And that's interesting because you're like slicing up math now

934
00:46:34,360 --> 00:46:37,600
Speaker 1: into different categories which are a little bit arbitrary, right,

935
00:46:37,600 --> 00:46:41,320
Speaker 1: Like calculus uses trigonometry and algebra and all of these things.

936
00:46:41,360 --> 00:46:43,960
Speaker 1: But there actually is a really interesting effort inside of

937
00:46:44,040 --> 00:46:47,000
Speaker 1: math to try to like boil all of math down

938
00:46:47,120 --> 00:46:49,840
Speaker 1: into the shortest list of rules you would need to

939
00:46:49,920 --> 00:46:52,319
Speaker 1: build up all the rest of math, like to find

940
00:46:52,400 --> 00:46:55,040
Speaker 1: the core axioms at the heart of it all. Oh, yeah,

941
00:46:55,080 --> 00:46:57,680
Speaker 1: where is that coming from? From the math fields or

942
00:46:57,800 --> 00:47:00,200
Speaker 1: from the physics fields? That comes from mathematics? Like a

943
00:47:00,280 --> 00:47:02,759
Speaker 1: hundred fifty years ago, people have been doing math for

944
00:47:02,800 --> 00:47:04,920
Speaker 1: thousands of years. About a hundred and fifty years ago,

945
00:47:04,920 --> 00:47:07,080
Speaker 1: people were like, hold on a second, what are the

946
00:47:07,120 --> 00:47:09,840
Speaker 1: basic rules of math? Anyway? And so there was a

947
00:47:09,840 --> 00:47:12,919
Speaker 1: guy named Piano who showed that almost all of arithmetic

948
00:47:13,120 --> 00:47:15,280
Speaker 1: can be boiled down to just a basic fuel rules,

949
00:47:15,400 --> 00:47:17,960
Speaker 1: and then people who came after him showed that most

950
00:47:18,000 --> 00:47:20,839
Speaker 1: of math could be boiled down to arithmetic, and then

951
00:47:20,920 --> 00:47:23,600
Speaker 1: later people showed that most arithmetic can be boiled down

952
00:47:23,640 --> 00:47:26,600
Speaker 1: to something called set theory, which is math about like

953
00:47:26,880 --> 00:47:29,200
Speaker 1: groups and what's in a group, what's out of a group?

954
00:47:29,200 --> 00:47:31,480
Speaker 1: How do you combine groups? How do you overlap groups?

955
00:47:31,560 --> 00:47:34,120
Speaker 1: So the current like idea about the very foundation of

956
00:47:34,160 --> 00:47:36,240
Speaker 1: math is that in the end, it's all about sets.

957
00:47:36,360 --> 00:47:38,600
Speaker 1: It's all about like what's in a group, what's out

958
00:47:38,600 --> 00:47:41,120
Speaker 1: of group? From that you can build arithmetic, and from

959
00:47:41,160 --> 00:47:44,520
Speaker 1: that you can build calculus. So fundamentally, we think that

960
00:47:44,560 --> 00:47:47,359
Speaker 1: the description of the universe is mathematical and it's all

961
00:47:47,440 --> 00:47:49,480
Speaker 1: set theory all the way down. That's kind of what

962
00:47:49,520 --> 00:47:53,719
Speaker 1: I was saying, Right, there's addition. Basically, it's just a

963
00:47:53,800 --> 00:47:58,120
Speaker 1: group exactly. It's addition and its popularity. It's all clicks

964
00:48:00,120 --> 00:48:03,640
Speaker 1: versus very elitist or it's all about clickbait. All right, Well,

965
00:48:03,640 --> 00:48:06,399
Speaker 1: I think that answers Matthew's question, what is the math

966
00:48:06,400 --> 00:48:09,239
Speaker 1: of the universe? Well, the answer is, so far calculus

967
00:48:09,280 --> 00:48:12,520
Speaker 1: has been really useful in describing the universe, but um

968
00:48:12,680 --> 00:48:15,840
Speaker 1: physicists are not sure if maybe even calculus is the

969
00:48:15,880 --> 00:48:18,959
Speaker 1: fundamental way to describe the universe, or even the most

970
00:48:18,960 --> 00:48:22,640
Speaker 1: fundamental um way to describe math itself. That's right, but

971
00:48:22,680 --> 00:48:25,120
Speaker 1: that doesn't mean we don't like thinking about these questions

972
00:48:25,120 --> 00:48:27,120
Speaker 1: and wondering about what's going on in the heart of

973
00:48:27,120 --> 00:48:29,920
Speaker 1: the universe and why it is even possible to describe

974
00:48:29,920 --> 00:48:32,480
Speaker 1: it mathematically or to make sense of it with our

975
00:48:32,520 --> 00:48:35,279
Speaker 1: little primate brains. So you're gonna keep going until it

976
00:48:35,320 --> 00:48:37,320
Speaker 1: all adds up, or until you ask what the heck?

977
00:48:37,920 --> 00:48:39,960
Speaker 1: I can't even until we're part of the in group

978
00:48:40,000 --> 00:48:42,520
Speaker 1: that actually knows some answers, until we're all guinea pigs,

979
00:48:43,200 --> 00:48:45,759
Speaker 1: we're all test subjects in this universe living on the

980
00:48:45,760 --> 00:48:49,640
Speaker 1: surface of some crazy exo moon or black hole. All right, Well,

981
00:48:49,680 --> 00:48:53,440
Speaker 1: thank you to everyone who sent in their questions. We

982
00:48:53,520 --> 00:48:56,800
Speaker 1: love answering questions. We hope you enjoyed that. Thanks for

983
00:48:56,880 --> 00:49:07,000
Speaker 1: joining us. See you next time. Ye, thanks for listening,

984
00:49:07,040 --> 00:49:09,799
Speaker 1: and remember that Daniel and Jorge Explain the Universe is

985
00:49:09,800 --> 00:49:13,200
Speaker 1: a production of I Heart Radio. For more podcast for

986
00:49:13,320 --> 00:49:17,080
Speaker 1: my heart Radio, visit the I heart Radio app, Apple Podcasts,

987
00:49:17,200 --> 00:49:25,319
Speaker 1: or wherever you listen to your favorite shows. Yeah.