WEBVTT - How metallic is the Sun?

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<v Speaker 1>Hey, or Hey, how's your dad band going?

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<v Speaker 2>Uh? Pretty good? Yeah, we're getting better. It's a lot

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<v Speaker 2>of fun, didn't you guys have some clever name, sort

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<v Speaker 2>of clever. We call ourselves the Grateful Dads.

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<v Speaker 1>And is that the kind of music you play? Psychedelic

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<v Speaker 1>sixties rock or are you more like alternative or metal?

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<v Speaker 2>We play a little bit of everything, you know, Eighties music,

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<v Speaker 2>nineties rock, some Marvin Gaye, some Pink Floyd, a little bit.

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<v Speaker 1>Of all right. So then the physicist in me wants

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<v Speaker 1>to know how metal are you guys?

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<v Speaker 2>I would say we're less and Iron Maiden, maybe more

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<v Speaker 2>than the Doobie Brothers.

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<v Speaker 1>That sounds like it leaves a lot of uncertainty.

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<v Speaker 2>That's for sure. We always try to rocket.

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<v Speaker 1>Hi.

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<v Speaker 2>I'm Horem and Cartoonez and the author of Oliver's Great

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<v Speaker 2>Big Universe.

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<v Speaker 1>Hi. I'm Daniel. I'm a particle physicist and a professor

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<v Speaker 1>at UC Irvine, and I like music with all different

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<v Speaker 1>kinds of metal.

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<v Speaker 2>You mean, like the instruments or like the genre the genre?

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<v Speaker 1>You know, A little heavy metal, little light metal? Is

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<v Speaker 1>light metal even a thing?

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<v Speaker 2>M I think some of these heavy metal groups have

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<v Speaker 2>saw songs. Does that still count as metal.

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<v Speaker 1>I'm not even going to weigh in on that.

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<v Speaker 2>Yeah, we don't want to anger those metal people. M

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<v Speaker 2>they're pretty intense. But anyways, Welcome to our podcast Daniel

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<v Speaker 2>and Jorge Explain the Universe, a production of iHeartRadio.

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<v Speaker 1>In which we attempt to understand everything in the universe,

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<v Speaker 1>from the tiny quantum particles to the amazing shiny metals

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<v Speaker 1>that make up our universe. We want to know how

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<v Speaker 1>everything in the universe functions. We want to know what

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<v Speaker 1>its smallest bits are and how they come together to

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<v Speaker 1>explain everything in our amazing, crazy, delicious and bonkers universe.

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<v Speaker 2>That's right, because the universe is made out of all

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<v Speaker 2>kinds of things, and in this podcast we'd like to

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<v Speaker 2>explore all of it and to figure out what it's

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<v Speaker 2>all made out of, how it's all put together, and

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<v Speaker 2>what makes things the way they are.

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<v Speaker 1>How you can go from quantum particles to dad bands

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<v Speaker 1>in Pasadena or marching bands in New Mexico. The only

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<v Speaker 1>kind of band I've ever been in.

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<v Speaker 2>And did you play metal or did you play a

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<v Speaker 2>metal instrument?

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<v Speaker 1>Not even I played the totally unhearable instrument, the clarinet. Oh,

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<v Speaker 1>you can only hear the clarinet in the marching band

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<v Speaker 1>if you're literally in the middle of the clarinet section.

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<v Speaker 1>Otherwise it's just trumpets.

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<v Speaker 2>But the clarinet is made out of metal, isn't it?

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<v Speaker 2>Or is that one of the woodwinds.

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<v Speaker 1>It's a woodwind, though there are metal bits of course

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<v Speaker 1>to operate the holes.

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<v Speaker 2>And what kind of music did you guys play?

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<v Speaker 1>Oh? You know, we played marching band versions of all

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<v Speaker 1>your greatest.

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<v Speaker 2>Hits, including metal songs, including metal songs.

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<v Speaker 1>Absolutely, there's a marching band version of every song you love,

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<v Speaker 1>and we ruin it.

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<v Speaker 2>Maybe you should start a band with physicists.

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<v Speaker 1>What would we call it?

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<v Speaker 2>I don't know what would you call it?

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<v Speaker 1>Maybe some Higgs Boson reference. We make everything heavy?

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<v Speaker 2>How about you too have mass?

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<v Speaker 1>That's pretty good?

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<v Speaker 2>Or how about the clash of particles?

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<v Speaker 1>All right, now, I just need some musical talents that

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<v Speaker 1>I'm all set.

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<v Speaker 2>How about the doov Boson brothers?

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<v Speaker 1>All right? I think we're good on band names.

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<v Speaker 2>But yeah, it is interesting to think about all the

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<v Speaker 2>things that the stuff in the universe is made out of, right.

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<v Speaker 1>It is really interesting. It's fascinating to understand how all

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<v Speaker 1>that stuff got made and how it comes together to

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<v Speaker 1>make our universe, because even the tiniest little bits of

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<v Speaker 1>metal here and there are required, absolutely essential for the

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<v Speaker 1>universe to operate the way that it does.

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<v Speaker 2>Yeah, Because the universe, I guess, is made out of

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<v Speaker 2>all kinds of things, gases, solids, liquids, metals, non metals, acids, bases.

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<v Speaker 2>There's all kinds of ways that you can categorize the

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<v Speaker 2>stuff that stuff is made out of, right.

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<v Speaker 1>Yeah, absolutely, And though it's all made out of the

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<v Speaker 1>same fundamental bits. You take quarks and you mix them

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<v Speaker 1>together to make protons and neutrons, you add electrons. Those

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<v Speaker 1>few little ingredients can make all kinds of things out

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<v Speaker 1>there in the universe, with all kinds of different behaviors.

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<v Speaker 1>Some of them conduct electricity, some of them don't. Some

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<v Speaker 1>of them are strong, some of them are brittle, some

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<v Speaker 1>of them are soft, some of them interact, and some

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<v Speaker 1>of them don't. It's incredible the variety of stuff you

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<v Speaker 1>can make with just a few basic bits.

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<v Speaker 2>Some of the stuff is soft rock, some of it

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<v Speaker 2>is classical physics, some of it is heavy metals.

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<v Speaker 1>Literally, with the same instruments, you can make any kind

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<v Speaker 1>of music.

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<v Speaker 2>And with the same kinds of particles. You can make

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<v Speaker 2>everything that you see out there in the universe, all

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<v Speaker 2>the different kinds of stuff out there, And sometimes it's

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<v Speaker 2>kind of surprising all the different kinds of things that

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<v Speaker 2>we're made out of, right, Like, we're not just made

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<v Speaker 2>out of carbon and the basic building blocks, but there's

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<v Speaker 2>a bunch of weird things that it turns out are

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<v Speaker 2>sort of essential to our living. Right. Our bodies need copper.

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<v Speaker 1>Yeah, and oxygen for example, and all sorts of bits

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<v Speaker 1>to take advantage of the clever tricks of chemistry to

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<v Speaker 1>communicate information along our nerves. To capture oxygen in our

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<v Speaker 1>red blood cells, you need all sorts of elements. So

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<v Speaker 1>it's wonderful that these things exist out there in the universe,

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<v Speaker 1>that they've been somehow manufactured through physics in order to

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<v Speaker 1>shape our existence.

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<v Speaker 2>Now, some of us have more or less metal inside

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<v Speaker 2>of us, right, I mean, I grew up in the eighties,

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<v Speaker 2>and so my teeth are full of metals, all kinds

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<v Speaker 2>of metals in there. Absolutely, you got some lead grills.

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<v Speaker 1>And some of us probably played with mercury as a kid,

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<v Speaker 1>and so we have more or less mercury in us.

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<v Speaker 2>Yeah, did you play with Mercury. I play with Mercury

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<v Speaker 2>all the time, which probably maybe explains a lot.

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<v Speaker 1>That's why you're in a heavy metal band now, Yeah.

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<v Speaker 2>Yeah, that's why I'm so Mercuriers. But yeah, it kind

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<v Speaker 2>of makes you wonder what else the stuff out there

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<v Speaker 2>in the universe is made out of. You know, even

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<v Speaker 2>our planet I'm sure is mostly iron and rocks and silica.

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<v Speaker 2>But the stuff out there in space, what is that

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<v Speaker 2>made out of?

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<v Speaker 1>Yeah? Most of the stuff in the Solar System is

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<v Speaker 1>not us or even the Earth. An overwhelming fraction of

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<v Speaker 1>the Solar System is basically just the Sun. And of

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<v Speaker 1>course the Sun is crucial to life on Earth and

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<v Speaker 1>the operation of the Solar system. So it's in our

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<v Speaker 1>interest to understand, like, hey, what's in the sun because

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<v Speaker 1>that affects how long it's going to last and how

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<v Speaker 1>it behaves.

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<v Speaker 2>And so today on the podcast, we'll be tackling the

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<v Speaker 2>question how much metal is in the sun, not how

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<v Speaker 2>much metal is the sun?

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<v Speaker 1>How metal is the sun? If it had a dad band,

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<v Speaker 1>what would it play?

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<v Speaker 2>Well, we probably play a lot of songs about the sun.

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<v Speaker 2>You know, here comes the Sun, you are my sunshine.

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<v Speaker 1>It's opening has to be. Here comes the Sun. Absolutely,

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<v Speaker 1>that's its walk on music. For sure, that's their theme music.

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<v Speaker 2>Who would the son being a band with Jupiter, I guess,

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<v Speaker 2>or other suns?

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<v Speaker 1>It might outshine Jupiter.

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<v Speaker 2>Yeah, or maybe it's a solo act. Can you be

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<v Speaker 2>a solo metal act?

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<v Speaker 1>Probably you'd have to because nobody wants to be in

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<v Speaker 1>the Sun's shadow.

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<v Speaker 2>I think if you're next to the Sun, you're definitely

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<v Speaker 2>not in the shadow.

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<v Speaker 1>I know. I love how that joke made no sense.

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<v Speaker 2>Yeah, I'm trying to save it there, but no, you know,

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<v Speaker 2>I'm finding the loss of physics here.

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<v Speaker 1>Daniel, No, I was going for maximum nonsense.

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<v Speaker 2>Hmm, right, right, was on purpose. There's very metal of you.

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<v Speaker 2>If he has shouted it out, it would be even

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<v Speaker 2>more metal.

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<v Speaker 1>This is a really fascinating topic to me because I

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<v Speaker 1>love mysteries in our own neighborhood. You know, we wonder

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<v Speaker 1>about what's going on at the edge of the universe

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<v Speaker 1>or the beginning of time. But gosh darn it, we

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<v Speaker 1>haven't even figured out what our own solar system is

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<v Speaker 1>made out of.

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<v Speaker 2>We live in it, but we don't know kind of

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<v Speaker 2>what's in it, what's it all made out of? But

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<v Speaker 2>it's kind of an interesting question because you're particularly asking

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<v Speaker 2>how much metal is in the sun, not like what

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<v Speaker 2>is the sun made out of? Because I guess most

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<v Speaker 2>of the sun is just one thing, right.

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<v Speaker 1>Yeah, the sun is mostly hydrogen and a little bit

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<v Speaker 1>of helium, and what you call the rest is kind

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<v Speaker 1>of up for debate. I cringe to inform you that

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<v Speaker 1>it depends on your definition of metal, because in astronomy,

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<v Speaker 1>metal is anything but hydrogen or helium.

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<v Speaker 2>Right. I was going to mention that, like, what exactly

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<v Speaker 2>do you mean by metal? Because the metal means different

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<v Speaker 2>things to different people, right, yeah, exactly. I feel like

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<v Speaker 2>to us or to the everyday person, a metal is

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<v Speaker 2>something that's shiny and hard conducts electricity. Now is that wrong?

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<v Speaker 1>No, It's totally reasonable to think metals are things that

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<v Speaker 1>are metallic that have those properties, right, And that's how chemists,

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<v Speaker 1>for example, use the word metal, But astronomers think about

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<v Speaker 1>things differently.

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<v Speaker 2>Wait wait, wait, so is there an official definition of

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<v Speaker 2>metal by chemists that's different than the definition of metals

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<v Speaker 2>by physicists.

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<v Speaker 1>Well, by astronomers in particular, because the condensed matter physicists

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<v Speaker 1>would agree with the chemists because they're sort of almost

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<v Speaker 1>on the chemistry side physics. But astronomers, Wow, that's their

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<v Speaker 1>own community, and you know they got their issues with

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<v Speaker 1>naming stuff. There's fights about everything.

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<v Speaker 2>M okay. So then if we're asking how much metal

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<v Speaker 2>is in the sun, what are we asking like how

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<v Speaker 2>much non helium and hydrogen is in the sun? Or

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<v Speaker 2>are we asking how much metallic shining stuff is in

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<v Speaker 2>the sun?

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<v Speaker 3>Well?

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<v Speaker 1>I want to know everything about what's in the sun,

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<v Speaker 1>like how much iron is there anywhere? And where did

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<v Speaker 1>it come from? How could iron get into the sun?

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<v Speaker 1>But we don't even know very well the answer to

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<v Speaker 1>the more basic question, which is how much non hydrogen

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<v Speaker 1>and helium is there in the sun? How much astronomy

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<v Speaker 1>metal is in the sun.

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<v Speaker 2>Oh okay, so we're really asking the question how much

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<v Speaker 2>of the sun is not hydrogen or helium?

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<v Speaker 1>Yeah? Exactly.

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<v Speaker 2>Can we ask later how much of the sun is

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<v Speaker 2>the shining metallic stuff.

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<v Speaker 1>I mean, you're very mercurious, so you're allowed to ask anything.

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<v Speaker 2>A mercurious said mercurious?

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<v Speaker 1>Yeah?

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<v Speaker 2>Is that like a merman? But like a curious merman?

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<v Speaker 1>Well, you know, I guess you can be bi curious,

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<v Speaker 1>you can be mercurious. You know, I don't know what

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<v Speaker 1>that means. I'll let you figure that out. You just

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<v Speaker 1>want to dive into everything.

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<v Speaker 2>Yeah, I want to know it at all, but only

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<v Speaker 2>for a short amount of time. But anyways, how much

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<v Speaker 2>metal is in the sun, that's an interesting question. How

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<v Speaker 2>did you come up with this question?

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<v Speaker 1>Well, I was reading some papers about the mysteries of

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<v Speaker 1>how much metal is in the sun. I thought it

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<v Speaker 1>was fascinating that we still don't know the answer to

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<v Speaker 1>this pretty basic question that influences like the most important

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<v Speaker 1>thing in our neighborhood.

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<v Speaker 3>Hmmm.

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<v Speaker 2>Interesting, And I think also like what's in the sun

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<v Speaker 2>sort of affects the kind of light that we get

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<v Speaker 2>from the sun, right, Like you can tell what kinds

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<v Speaker 2>of things are inside of a star by looking at

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<v Speaker 2>its light.

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<v Speaker 1>And it has really cosmic consequences because we use the

0:10:42.920 --> 0:10:45.480
<v Speaker 1>Sun to calibrate our understanding of what's in the rest

0:10:45.520 --> 0:10:48.640
<v Speaker 1>of the universe, and the amount of metal in stars

0:10:48.720 --> 0:10:51.520
<v Speaker 1>controls their fate, like whether they'll collapse into a black

0:10:51.559 --> 0:10:54.400
<v Speaker 1>hole or not, and also how likely they are to

0:10:54.520 --> 0:10:57.640
<v Speaker 1>have planets around them. And so if we revise our

0:10:57.720 --> 0:10:59.560
<v Speaker 1>understanding of what's in the sun, it could change our

0:10:59.640 --> 0:11:02.720
<v Speaker 1>understand of what's out there in the universe, how long

0:11:02.760 --> 0:11:06.119
<v Speaker 1>it will last, and the likelihood that there could be aliens.

0:11:06.360 --> 0:11:08.600
<v Speaker 1>So yeah, in the end, it always connects to aliens.

0:11:09.920 --> 0:11:14.679
<v Speaker 2>Where did that come from? Is this just a big

0:11:14.720 --> 0:11:16.200
<v Speaker 2>excuse to talk about aliens again?

0:11:16.440 --> 0:11:18.840
<v Speaker 1>That's what this whole podcast is. Are you just figuring

0:11:18.840 --> 0:11:19.200
<v Speaker 1>that out?

0:11:20.280 --> 0:11:24.640
<v Speaker 2>Yeah, a little bit. Yeah, that we were explaining the universe.

0:11:24.920 --> 0:11:26.600
<v Speaker 1>It's just a fun for talking about aliens.

0:11:26.679 --> 0:11:29.079
<v Speaker 2>I see. This is all just a ployed to what

0:11:29.160 --> 0:11:34.200
<v Speaker 2>prepares us subconsciously for the imminent arrival of aliens or

0:11:34.240 --> 0:11:36.240
<v Speaker 2>the big reveal that you are an alien?

0:11:36.520 --> 0:11:37.080
<v Speaker 1>No comment.

0:11:38.480 --> 0:11:42.040
<v Speaker 2>Yeah, that's very suspicious, all right. So, as usual, we

0:11:42.040 --> 0:11:44.000
<v Speaker 2>were wondering how many people out there had thought about

0:11:44.000 --> 0:11:47.800
<v Speaker 2>this question and about the amount of metal in the sun.

0:11:48.040 --> 0:11:50.560
<v Speaker 1>Thanks very much to everybody who answers these questions. I

0:11:50.640 --> 0:11:53.040
<v Speaker 1>love hearing your thoughts on the question of the day,

0:11:53.120 --> 0:11:56.240
<v Speaker 1>so please don't be shy. If you would like to contribute,

0:11:56.280 --> 0:11:58.640
<v Speaker 1>write to me two questions at Daniel and Jorge dot

0:11:58.640 --> 0:12:00.000
<v Speaker 1>com and I'll get you on the air.

0:12:00.360 --> 0:12:02.040
<v Speaker 2>So think about it for a second. How much metal

0:12:02.080 --> 0:12:04.680
<v Speaker 2>do you think is in the sun. Here's what be

0:12:04.760 --> 0:12:05.280
<v Speaker 2>bled to say.

0:12:05.679 --> 0:12:08.360
<v Speaker 1>I think the heavier elements only come out during supernova's

0:12:08.400 --> 0:12:10.959
<v Speaker 1>and so I would have to say no metal in

0:12:11.000 --> 0:12:11.400
<v Speaker 1>the Sun.

0:12:11.840 --> 0:12:14.040
<v Speaker 2>I think that nineteen nine percent of the Solar System's

0:12:14.120 --> 0:12:17.240
<v Speaker 2>metals allocated in the Sun itself. But with regards to

0:12:17.280 --> 0:12:19.400
<v Speaker 2>the makeup of the Sun, I think that only about

0:12:19.440 --> 0:12:21.120
<v Speaker 2>eight percent of it is metal. The rest of it

0:12:21.160 --> 0:12:21.680
<v Speaker 2>is gas.

0:12:22.120 --> 0:12:23.479
<v Speaker 1>Most of it is fine.

0:12:24.320 --> 0:12:27.240
<v Speaker 3>I want to guess not very much right now, like

0:12:27.360 --> 0:12:31.000
<v Speaker 3>less than one percent. But as the Sun grows older,

0:12:31.320 --> 0:12:33.440
<v Speaker 3>maybe the amount of metal in the core will increase

0:12:33.559 --> 0:12:36.800
<v Speaker 3>until the mass becomes so great that the light cannot escape,

0:12:37.320 --> 0:12:38.960
<v Speaker 3>and then the Sun will turn black.

0:12:39.679 --> 0:12:42.160
<v Speaker 4>If we measured that diameter of the outer core, I

0:12:42.160 --> 0:12:44.200
<v Speaker 4>would assume that the metal is like less than like

0:12:44.240 --> 0:12:48.600
<v Speaker 4>ten percent of like the diameter with But I feel

0:12:48.600 --> 0:12:51.800
<v Speaker 4>like it's a truck question because don't cosmologists say anything

0:12:51.800 --> 0:12:53.360
<v Speaker 4>above helium as a metal, so this might be a

0:12:53.400 --> 0:12:56.520
<v Speaker 4>true question. I'm going to go ninety eight percent metal.

0:12:56.840 --> 0:12:58.800
<v Speaker 5>The Sun is totally metal, but I think if we're

0:12:58.800 --> 0:13:02.080
<v Speaker 5>talking about actual companies, there's not all that much. I'm

0:13:02.080 --> 0:13:03.720
<v Speaker 5>going to guess that the Sun has a little bit

0:13:03.720 --> 0:13:06.640
<v Speaker 5>of metal, like maybe one or two percent of its

0:13:06.800 --> 0:13:10.079
<v Speaker 5>total composition, but that's actually considered a lot compared to

0:13:10.120 --> 0:13:12.320
<v Speaker 5>other stars, and that the stars that came before the

0:13:12.320 --> 0:13:13.480
<v Speaker 5>sun had even less metal.

0:13:14.120 --> 0:13:16.600
<v Speaker 2>All right, Like the person who said the sun is

0:13:16.720 --> 0:13:17.880
<v Speaker 2>totally metal.

0:13:20.960 --> 0:13:22.720
<v Speaker 1>The sun has a good attitude. I think that's what

0:13:22.760 --> 0:13:23.160
<v Speaker 1>he means.

0:13:23.240 --> 0:13:27.520
<v Speaker 2>Yeah, well it is pretty hot, I guess intense.

0:13:27.679 --> 0:13:31.760
<v Speaker 1>Yeah, it's just not back down. Yeah, it just keeps

0:13:31.840 --> 0:13:33.080
<v Speaker 1>rocking on and on.

0:13:33.600 --> 0:13:36.400
<v Speaker 2>Yeah, and it eventually burns up. So that kind of

0:13:36.400 --> 0:13:38.920
<v Speaker 2>fits the heavy metal rock star.

0:13:39.320 --> 0:13:41.360
<v Speaker 1>Trope, flaming out as a pretty metal thing to do.

0:13:42.200 --> 0:13:44.760
<v Speaker 2>Yeah, all right, well, Daniel, maybe start with the basics.

0:13:44.960 --> 0:13:48.160
<v Speaker 2>How does a star even get metal in it? Because,

0:13:48.440 --> 0:13:51.920
<v Speaker 2>as we all know, stars are made out of hydrogen,

0:13:52.000 --> 0:13:55.439
<v Speaker 2>helium or hydrogen initially, right, all stars, or at least

0:13:55.440 --> 0:13:57.360
<v Speaker 2>the original stars were made out of hydrogen.

0:13:57.559 --> 0:14:00.480
<v Speaker 1>Yeah, it's a cool question. Stars can get metal in

0:14:00.520 --> 0:14:02.320
<v Speaker 1>them in two ways. One is that they can be

0:14:02.360 --> 0:14:05.319
<v Speaker 1>formed with metal in them. Stars come from a collapse

0:14:05.320 --> 0:14:07.040
<v Speaker 1>of a big cloud of like gas and dust and

0:14:07.080 --> 0:14:09.680
<v Speaker 1>other bits, So there's metal in the neighborhood. When the

0:14:09.720 --> 0:14:13.080
<v Speaker 1>star collapses, then that metal will become part of the star.

0:14:13.679 --> 0:14:16.280
<v Speaker 1>But that depends, as you were alluding to, on what's

0:14:16.280 --> 0:14:19.640
<v Speaker 1>around what's been made? Has something else out there? Made metal,

0:14:20.120 --> 0:14:21.920
<v Speaker 1>And the only way that we know to make metal

0:14:22.080 --> 0:14:24.400
<v Speaker 1>is in the hearts of stars. So the second way

0:14:24.400 --> 0:14:26.160
<v Speaker 1>that stars can get metal in them is they can

0:14:26.200 --> 0:14:30.120
<v Speaker 1>make metal. They confuse hydrogen and helium together to make

0:14:30.200 --> 0:14:32.120
<v Speaker 1>heavier stuff producing metal.

0:14:32.360 --> 0:14:34.560
<v Speaker 2>I meaning like when a star was formed and it

0:14:34.680 --> 0:14:37.200
<v Speaker 2>gathered all the gas to become a star, maybe there

0:14:37.280 --> 0:14:40.480
<v Speaker 2>were metals floating around where all this stuff was, and

0:14:40.520 --> 0:14:42.680
<v Speaker 2>that's how metal got inside the star. But were the

0:14:42.720 --> 0:14:45.280
<v Speaker 2>first stars made out of pure hydrogen or that the

0:14:45.400 --> 0:14:47.200
<v Speaker 2>universe makes a metal at the Big bang?

0:14:47.360 --> 0:14:50.280
<v Speaker 1>Yeah, great question. So about millions of a second after

0:14:50.320 --> 0:14:53.760
<v Speaker 1>the sort of primordial do things were expanding and cooling,

0:14:54.040 --> 0:14:57.080
<v Speaker 1>and you got quarks forming into protons and neutrons and

0:14:57.440 --> 0:15:00.520
<v Speaker 1>protons are hydrogen, So basically the first thing that made

0:15:00.960 --> 0:15:04.240
<v Speaker 1>was hydrogen. Because protons form, then you have a few

0:15:04.280 --> 0:15:07.240
<v Speaker 1>minutes in which the conditions are ripe for fusion for

0:15:07.320 --> 0:15:10.840
<v Speaker 1>those protons to bang together and make heavier stuff. And

0:15:10.920 --> 0:15:13.600
<v Speaker 1>so that's when helium was made. But you only had

0:15:13.640 --> 0:15:16.560
<v Speaker 1>like three minutes where the universe was in the right

0:15:16.560 --> 0:15:20.320
<v Speaker 1>conditions to make anything heavier, So you had huge amounts

0:15:20.320 --> 0:15:23.200
<v Speaker 1>of hydrogen, made a little bit of helium, but almost

0:15:23.200 --> 0:15:26.280
<v Speaker 1>nothing else. Basically, after the Big Bang, you had vast

0:15:26.400 --> 0:15:31.120
<v Speaker 1>quantities of hydrogen, trace amounts of helium, and almost nothing else. Basically,

0:15:31.160 --> 0:15:33.920
<v Speaker 1>no metal was around after the Big Bang.

0:15:34.880 --> 0:15:37.880
<v Speaker 2>Although I hear you saying almost, does that mean that

0:15:37.880 --> 0:15:41.280
<v Speaker 2>there was a little bit of the heavier metals in

0:15:41.320 --> 0:15:45.040
<v Speaker 2>the universe right after the Big Bang before stars got made.

0:15:45.120 --> 0:15:47.040
<v Speaker 1>It's impossible to say that there was none, But it's

0:15:47.120 --> 0:15:50.120
<v Speaker 1>very hard to make those heavier elements without the density

0:15:50.160 --> 0:15:54.120
<v Speaker 1>and the time. Using helium together makes something very unstable.

0:15:54.160 --> 0:15:56.840
<v Speaker 1>If you just start with two helium nuclei, you really

0:15:56.880 --> 0:15:59.640
<v Speaker 1>need three together to get the carbon, and that's much

0:15:59.680 --> 0:16:01.920
<v Speaker 1>harder to do without the density that you have in

0:16:02.040 --> 0:16:05.280
<v Speaker 1>stars and the time to fuse them. So it's possible

0:16:05.320 --> 0:16:07.640
<v Speaker 1>you made a little tiny bit of carbon after the

0:16:07.640 --> 0:16:11.560
<v Speaker 1>Big Bang, but it's overwhelmingly hydrogen, a little bit of helium,

0:16:11.600 --> 0:16:15.160
<v Speaker 1>and maybe tiny negligible amounts of carbon mm.

0:16:16.520 --> 0:16:20.440
<v Speaker 2>So the universe, I guess, was pretty pure hydrogen and helium,

0:16:20.480 --> 0:16:23.160
<v Speaker 2>and then those started to make stars, and that's when

0:16:23.200 --> 0:16:26.760
<v Speaker 2>the first metals really came into the universe exactly.

0:16:26.800 --> 0:16:30.160
<v Speaker 1>So those first stars were basically metal free, just huge

0:16:30.240 --> 0:16:33.160
<v Speaker 1>clouds of hydrogen with a little bit of helium in them,

0:16:33.400 --> 0:16:36.720
<v Speaker 1>and they produced the first metals. Right, they didn't start

0:16:36.720 --> 0:16:39.320
<v Speaker 1>with really any metal in them at all, but these

0:16:39.360 --> 0:16:42.480
<v Speaker 1>were huge stars. Turns out, if you form stars without

0:16:42.560 --> 0:16:46.000
<v Speaker 1>any metal in them, you get much bigger globs. And

0:16:46.080 --> 0:16:48.720
<v Speaker 1>those stars are really big, so they burn really hot

0:16:48.960 --> 0:16:51.360
<v Speaker 1>and they burn really fast, so they don't last for

0:16:51.480 --> 0:16:54.360
<v Speaker 1>very long. And then when they die, they spray their

0:16:54.400 --> 0:16:57.400
<v Speaker 1>metals out into the universe to see the next stars.

0:16:57.720 --> 0:17:00.640
<v Speaker 2>Right, and some of them burn and explode and collapse

0:17:00.920 --> 0:17:03.600
<v Speaker 2>without having used up all of the hydrogen and helium.

0:17:03.640 --> 0:17:06.320
<v Speaker 1>Right, Oh, yes, absolutely, stars do not burn all of

0:17:06.320 --> 0:17:08.920
<v Speaker 1>their hydrogen helium before they end their lives.

0:17:09.080 --> 0:17:11.600
<v Speaker 2>So like when those first stars exploded, how much of

0:17:11.640 --> 0:17:14.719
<v Speaker 2>them was still hydrogen and helium and how much of

0:17:14.760 --> 0:17:16.520
<v Speaker 2>the heavier metals had they made.

0:17:16.680 --> 0:17:18.760
<v Speaker 1>Yeah, that's a cool question. We can answer that by

0:17:18.840 --> 0:17:21.600
<v Speaker 1>looking at how much metal is in the next generation

0:17:21.680 --> 0:17:24.520
<v Speaker 1>of stars, because those little bits of metal are excellent

0:17:24.640 --> 0:17:28.160
<v Speaker 1>seeds for the next stars. Like, metal is heavier than

0:17:28.200 --> 0:17:30.679
<v Speaker 1>non metal, it has more protons, and it is more mass,

0:17:30.800 --> 0:17:34.120
<v Speaker 1>it's denser, so it's more likely to form a seed

0:17:34.160 --> 0:17:37.639
<v Speaker 1>of another star start that gravitational collapse. So the next

0:17:37.680 --> 0:17:41.040
<v Speaker 1>generation of stars. The stars were called population two. These

0:17:41.080 --> 0:17:43.760
<v Speaker 1>are still really really low metal. It's like less than

0:17:43.840 --> 0:17:47.760
<v Speaker 1>a tenth of one percent of those stars is metal,

0:17:47.880 --> 0:17:51.879
<v Speaker 1>so it's still overwhelmingly hydrogen and helium. Even in the

0:17:51.880 --> 0:17:54.480
<v Speaker 1>second generation of stars whoa.

0:17:54.440 --> 0:17:58.280
<v Speaker 2>So maybe painted pictures. So those first stars burned, they collapse,

0:17:58.320 --> 0:18:02.280
<v Speaker 2>They exploded, and then all that stuff recollapsed to get.

0:18:02.359 --> 0:18:05.240
<v Speaker 1>Yeah, exactly, but it didn't happen that quickly. Helium floats

0:18:05.280 --> 0:18:08.040
<v Speaker 1>around for like hundreds of millions of years before the

0:18:08.080 --> 0:18:10.800
<v Speaker 1>first stars are born. There's this period in the early

0:18:10.880 --> 0:18:13.840
<v Speaker 1>universe called the dark Ages, before there was any light

0:18:13.920 --> 0:18:17.320
<v Speaker 1>in the universe, just these dark clouds of hydrogen and helium.

0:18:17.680 --> 0:18:19.840
<v Speaker 1>And then those first stars burn for like just a

0:18:19.880 --> 0:18:22.800
<v Speaker 1>few million years. The larger the star is, the shorter

0:18:22.920 --> 0:18:25.119
<v Speaker 1>it's life. So those didn't burn for very long. But

0:18:25.160 --> 0:18:28.199
<v Speaker 1>then the next generation they're a little smaller and they

0:18:28.240 --> 0:18:30.399
<v Speaker 1>can burn for a very very long time.

0:18:30.640 --> 0:18:31.600
<v Speaker 2>Why were they smaller.

0:18:31.680 --> 0:18:33.280
<v Speaker 1>The more metal you have in the universe, the more

0:18:33.359 --> 0:18:35.960
<v Speaker 1>likely it is that a big cloud of gas is

0:18:35.960 --> 0:18:38.399
<v Speaker 1>going to break up and do multiple stars rather than

0:18:38.440 --> 0:18:41.800
<v Speaker 1>collapsing into one megastar, because you have all these different

0:18:41.800 --> 0:18:44.320
<v Speaker 1>places for it to seed. Remember, that for a star

0:18:44.400 --> 0:18:47.040
<v Speaker 1>to form, you need sort of special conditions. You need

0:18:47.040 --> 0:18:49.240
<v Speaker 1>a big cloud of gas, but you need to also

0:18:49.280 --> 0:18:51.840
<v Speaker 1>be cold enough so that it can collapse, and you

0:18:51.880 --> 0:18:55.399
<v Speaker 1>need some like gravitational seed to get that runaway effect going.

0:18:56.000 --> 0:18:58.679
<v Speaker 1>And so if you have a variety of different densities,

0:18:58.840 --> 0:19:01.640
<v Speaker 1>you're more likely to have smaller clumps than bigger clumps.

0:19:01.920 --> 0:19:04.760
<v Speaker 1>And those smaller stars tend to burn colder, and then

0:19:04.800 --> 0:19:05.800
<v Speaker 1>they last longer.

0:19:06.040 --> 0:19:08.879
<v Speaker 2>So if you have a giant cloud of hydrogen, it

0:19:08.920 --> 0:19:12.160
<v Speaker 2>doesn't break up as much. It just hangs around until

0:19:12.240 --> 0:19:14.760
<v Speaker 2>it all condenses into a giant star exactly.

0:19:14.800 --> 0:19:17.040
<v Speaker 1>And people might be imagining like that one cloud makes

0:19:17.080 --> 0:19:20.159
<v Speaker 1>one star, but it's more likely that a huge cloud

0:19:20.200 --> 0:19:24.040
<v Speaker 1>makes multiple stars all simultaneously. And if that cloud has

0:19:24.080 --> 0:19:26.359
<v Speaker 1>more metal in it, then you have more seeds for

0:19:26.440 --> 0:19:28.840
<v Speaker 1>those stars, so you end up with more smaller stars

0:19:29.040 --> 0:19:32.399
<v Speaker 1>rather than fewer megastars like you did in the first batch.

0:19:33.240 --> 0:19:36.640
<v Speaker 2>Okay, so then that's the second generation of stars, right.

0:19:36.680 --> 0:19:40.320
<v Speaker 1>Yeah, exactly, And those stars were formed like thirteen fourteen

0:19:40.400 --> 0:19:43.400
<v Speaker 1>billion years ago, but they burn a long time because

0:19:43.440 --> 0:19:46.919
<v Speaker 1>they're small, they're redder, they're colder stars. So we can

0:19:46.960 --> 0:19:49.280
<v Speaker 1>still see some of those stars around in the universe,

0:19:49.560 --> 0:19:51.919
<v Speaker 1>especially in globular clusters.

0:19:51.720 --> 0:19:55.160
<v Speaker 2>Like around us or only far away or further back

0:19:55.200 --> 0:19:55.520
<v Speaker 2>in time.

0:19:55.560 --> 0:19:57.879
<v Speaker 1>They're also in like the heart of our galaxy. So

0:19:58.080 --> 0:19:59.919
<v Speaker 1>population two stars are all around.

0:20:00.280 --> 0:20:03.719
<v Speaker 2>Did that generation of stars then they eventually explode and

0:20:03.720 --> 0:20:05.639
<v Speaker 2>make the next generation of stars?

0:20:05.920 --> 0:20:08.840
<v Speaker 1>That definitely happened. It's a little bit misleading to think

0:20:08.880 --> 0:20:11.800
<v Speaker 1>about these as generations in a sort of crisp sense.

0:20:12.200 --> 0:20:14.320
<v Speaker 1>It's not like all that first generation died and then

0:20:14.359 --> 0:20:17.360
<v Speaker 1>there's only the second generation and there's only the third generation.

0:20:17.920 --> 0:20:20.679
<v Speaker 1>Every star is formed from remnants of multiple stars, and

0:20:20.760 --> 0:20:22.800
<v Speaker 1>some of them might have gone through one, two, three,

0:20:22.920 --> 0:20:26.200
<v Speaker 1>four generations, maybe even more. It depends on the size

0:20:26.240 --> 0:20:29.400
<v Speaker 1>of those stars. So this categorization is very rough. It's

0:20:29.440 --> 0:20:32.000
<v Speaker 1>not super precise. It's not like all the stars are

0:20:32.000 --> 0:20:35.399
<v Speaker 1>in sync. But the latest generation of stars, which are

0:20:35.440 --> 0:20:38.880
<v Speaker 1>called population one stars for more recently in the universe,

0:20:39.119 --> 0:20:41.920
<v Speaker 1>when there's been more time to make metal in the universe.

0:20:42.320 --> 0:20:45.520
<v Speaker 1>So these we call high metallicity stars, which means they

0:20:45.560 --> 0:20:48.240
<v Speaker 1>have like between one and four percent metal.

0:20:48.480 --> 0:20:50.880
<v Speaker 2>Wait wait, wait, the third generation of stars is called

0:20:50.920 --> 0:20:51.920
<v Speaker 2>population one.

0:20:52.480 --> 0:20:55.320
<v Speaker 1>Yeah, that's exactly right. Population one are the ones made

0:20:55.320 --> 0:20:59.600
<v Speaker 1>most recently. Population two is the previous generation. Population three

0:21:00.160 --> 0:21:04.399
<v Speaker 1>is still somewhat theoretical first generation of stars. And I

0:21:04.520 --> 0:21:06.640
<v Speaker 1>know the naming system is ridiculous, and I won't defend

0:21:06.680 --> 0:21:07.600
<v Speaker 1>it even for a moment.

0:21:07.760 --> 0:21:09.240
<v Speaker 2>What generation is our sun?

0:21:09.400 --> 0:21:11.919
<v Speaker 1>Our son we think is a population one star, so

0:21:11.920 --> 0:21:13.640
<v Speaker 1>it's part of the most recent generation.

0:21:13.880 --> 0:21:15.760
<v Speaker 2>All right, Well, then let's get to the question of

0:21:15.840 --> 0:21:19.119
<v Speaker 2>how much metal is in our star, the Sun, and

0:21:19.160 --> 0:21:22.240
<v Speaker 2>whether it rocks or not. So let's dig into that.

0:21:22.400 --> 0:21:37.200
<v Speaker 2>But first let's take a quick break. All right, we're

0:21:37.200 --> 0:21:40.480
<v Speaker 2>asking the question how much metal is in the Sun,

0:21:41.200 --> 0:21:44.280
<v Speaker 2>and by metal we mean elements that are not hydrogen

0:21:44.359 --> 0:21:44.800
<v Speaker 2>or helium.

0:21:44.880 --> 0:21:49.679
<v Speaker 1>Yeah, exactly. We want to know how much oxygen, carbon, neon, nitrogen, sulfur, iron,

0:21:49.760 --> 0:21:52.520
<v Speaker 1>all that stuff all added up. That's even like the

0:21:52.560 --> 0:21:54.679
<v Speaker 1>first most basic question you want to know, like how

0:21:54.760 --> 0:21:56.800
<v Speaker 1>much of that heavier stuff is in the Sun. And

0:21:56.840 --> 0:21:59.080
<v Speaker 1>then of course we want to know the proportions also,

0:21:59.160 --> 0:22:01.480
<v Speaker 1>But we first need to nail down the initial question.

0:22:01.920 --> 0:22:05.120
<v Speaker 2>Well, why do you think astronomers call everything not hygrogen

0:22:05.200 --> 0:22:08.440
<v Speaker 2>and helium metals because they couldn't come up with another name?

0:22:08.840 --> 0:22:12.160
<v Speaker 2>Or is there rationale there? Like I would think metals

0:22:12.560 --> 0:22:15.960
<v Speaker 2>maybe in chemistry has the connotation that it conducts electricity

0:22:16.160 --> 0:22:20.320
<v Speaker 2>or is shining. So what's the astronomer's excuse.

0:22:20.560 --> 0:22:23.520
<v Speaker 1>Well, I think there is this division between hydrogen helium,

0:22:23.720 --> 0:22:27.119
<v Speaker 1>of which there's so much in the universe, and everything else,

0:22:27.680 --> 0:22:30.000
<v Speaker 1>and so you really need another category. I don't know

0:22:30.040 --> 0:22:32.439
<v Speaker 1>if metal was the right way to describe it, but

0:22:32.560 --> 0:22:35.240
<v Speaker 1>there definitely are two different categories. There really is hydrogen

0:22:35.280 --> 0:22:37.320
<v Speaker 1>helium and all the other stuff in the universe.

0:22:37.400 --> 0:22:40.600
<v Speaker 2>M So it's more of a name just given by

0:22:40.640 --> 0:22:42.120
<v Speaker 2>population or abundancy.

0:22:43.200 --> 0:22:45.840
<v Speaker 1>Also, this is the stuff produced by stars, so it's

0:22:45.840 --> 0:22:48.480
<v Speaker 1>sort of like the output of stars. It doesn't have

0:22:48.520 --> 0:22:50.680
<v Speaker 1>to do as much with like the chemical properties or

0:22:50.720 --> 0:22:53.280
<v Speaker 1>the behaviors or the appearance the way it does in chemistry.

0:22:53.760 --> 0:22:56.040
<v Speaker 1>It's more about the abundance in the universe and how

0:22:56.040 --> 0:22:56.560
<v Speaker 1>it was made.

0:22:56.800 --> 0:22:59.639
<v Speaker 2>All right, So then the latest generation of star has

0:22:59.720 --> 0:23:03.720
<v Speaker 2>a one point four to four percent metals.

0:23:03.520 --> 0:23:06.680
<v Speaker 1>Yeah, exactly, And so there's a variation there, like depending

0:23:06.720 --> 0:23:08.920
<v Speaker 1>on where you were when you were formed, and also

0:23:08.920 --> 0:23:12.359
<v Speaker 1>whether you can make metals inside you. There's a pretty

0:23:12.359 --> 0:23:14.639
<v Speaker 1>big spread and how much metal there is in stars.

0:23:15.000 --> 0:23:18.520
<v Speaker 1>On the other hand, most stars still hydrogen helium. Like,

0:23:18.560 --> 0:23:22.760
<v Speaker 1>we've been burning hydrogen for fourteen billion years. We've hardly

0:23:22.760 --> 0:23:25.480
<v Speaker 1>made a dent in the fraction of the universe that

0:23:25.720 --> 0:23:27.119
<v Speaker 1>is hydrogen.

0:23:26.880 --> 0:23:29.880
<v Speaker 2>You mean our star or in the universe in general.

0:23:29.920 --> 0:23:32.560
<v Speaker 1>The universe in general, you know, the universe is still

0:23:33.000 --> 0:23:36.200
<v Speaker 1>mostly hydrogen. Like ninety two percent of the universe right

0:23:36.200 --> 0:23:37.720
<v Speaker 1>now is hydrogen.

0:23:37.880 --> 0:23:40.560
<v Speaker 2>So like our star right now is burning hydrogen. Were

0:23:40.600 --> 0:23:43.080
<v Speaker 2>you saying, like the amount of hydrogen it's burning or

0:23:43.359 --> 0:23:46.280
<v Speaker 2>fusing together is super tiny tiny.

0:23:46.280 --> 0:23:48.600
<v Speaker 1>I'm saying, we've been burning it for fourteen billion years

0:23:48.600 --> 0:23:50.840
<v Speaker 1>and we've hardly made a dent. Yeah, stars are the

0:23:50.920 --> 0:23:55.359
<v Speaker 1>universe's mechanism for like turning light stuff like hydrogen into

0:23:55.400 --> 0:23:57.320
<v Speaker 1>heavier stuff. And you might think, wow, we've been burning

0:23:57.320 --> 0:23:59.160
<v Speaker 1>for a long time. We must have plowed through it all.

0:23:59.200 --> 0:24:02.560
<v Speaker 1>But there's still vast, vast quantities of hydrogen out there.

0:24:02.640 --> 0:24:06.480
<v Speaker 2>Now, Why is that just because there's so much hydrogen

0:24:06.520 --> 0:24:08.440
<v Speaker 2>and helium in the sun. But really the part that

0:24:08.520 --> 0:24:11.520
<v Speaker 2>is fusing, it's only at the very tiny center of it.

0:24:11.680 --> 0:24:13.960
<v Speaker 2>Or why isn't it burning up faster?

0:24:14.280 --> 0:24:16.560
<v Speaker 1>The reason you suggest it is totally accurate. Like fusion

0:24:16.600 --> 0:24:19.199
<v Speaker 1>happens mostly at the core where things are dense and

0:24:19.240 --> 0:24:22.000
<v Speaker 1>things are hot, at least in the initial stages. Then

0:24:22.040 --> 0:24:24.280
<v Speaker 1>when the core of the sun fills with ash or

0:24:24.320 --> 0:24:27.480
<v Speaker 1>fills with heavier metals than the sun confuse, then the

0:24:27.520 --> 0:24:31.960
<v Speaker 1>fusion moves outwards. But also remember fusion is hard. Even

0:24:32.000 --> 0:24:34.440
<v Speaker 1>if you have an enormous pile of hydrogen you squeeze

0:24:34.440 --> 0:24:37.400
<v Speaker 1>it to the right pressure and density and temperature, it's

0:24:37.400 --> 0:24:39.560
<v Speaker 1>not like all the hydrogen is instantly just going to

0:24:39.600 --> 0:24:42.040
<v Speaker 1>fuse into helium. You need a lot of hydrogen and

0:24:42.080 --> 0:24:44.919
<v Speaker 1>a lot of time to get any fusion happening. So

0:24:44.960 --> 0:24:47.280
<v Speaker 1>it's a very low probability thing, which is why you

0:24:47.320 --> 0:24:51.160
<v Speaker 1>need an enormous pile a very high temperature, high density

0:24:51.160 --> 0:24:52.720
<v Speaker 1>gas to get any of it to happen.

0:24:53.000 --> 0:24:55.800
<v Speaker 2>All right, So then that's kind of the general picture.

0:24:55.840 --> 0:24:57.840
<v Speaker 2>But what about our sun? How much of our sun

0:24:57.960 --> 0:25:00.520
<v Speaker 2>is still hydrogen and helium and how much it is

0:25:00.920 --> 0:25:01.879
<v Speaker 2>badly named metals.

0:25:03.960 --> 0:25:06.560
<v Speaker 1>So about twenty years ago we thought we had this settled.

0:25:07.040 --> 0:25:09.080
<v Speaker 1>We had studied the sun and looked at the light

0:25:09.080 --> 0:25:10.840
<v Speaker 1>that comes from the sun, the spectrum of it, like

0:25:10.880 --> 0:25:12.920
<v Speaker 1>how much red light is there, how much green light,

0:25:12.920 --> 0:25:15.159
<v Speaker 1>how much blue light, and use that to try to

0:25:15.200 --> 0:25:17.040
<v Speaker 1>figure out what was in the sun, and we thought

0:25:17.040 --> 0:25:18.960
<v Speaker 1>we had it nailed down. We thought the answer was

0:25:19.000 --> 0:25:22.480
<v Speaker 1>about one point eight percent metal.

0:25:22.480 --> 0:25:24.480
<v Speaker 2>Meaning like if you look at the light from the Sun,

0:25:25.200 --> 0:25:27.439
<v Speaker 2>the spectrum of the light from the Sun sort of

0:25:27.480 --> 0:25:29.159
<v Speaker 2>can tell you what the Sun is made out of,

0:25:29.320 --> 0:25:30.120
<v Speaker 2>or we thought it could.

0:25:30.320 --> 0:25:33.320
<v Speaker 1>Yeah, exactly. The Sun is really fascinating because, on one hand,

0:25:33.440 --> 0:25:35.600
<v Speaker 1>a lot of the light comes from just the Sun

0:25:35.640 --> 0:25:38.440
<v Speaker 1>being hot. Everything out there in the universe that's made

0:25:38.480 --> 0:25:41.480
<v Speaker 1>of charged particles will glow based on its temperature, and

0:25:41.480 --> 0:25:44.159
<v Speaker 1>the hotter things are, the higher energy the photons it

0:25:44.200 --> 0:25:46.600
<v Speaker 1>will be released. So a lot of the light from

0:25:46.640 --> 0:25:48.880
<v Speaker 1>the Sun is what we call just black body radiation,

0:25:49.240 --> 0:25:51.880
<v Speaker 1>something hot giving off light the way like I give

0:25:51.880 --> 0:25:53.920
<v Speaker 1>off light and you give off light. We don't give

0:25:53.920 --> 0:25:56.080
<v Speaker 1>off light in the visible spectrum the way the Sun

0:25:56.119 --> 0:25:58.720
<v Speaker 1>does because we're not white hot the way the Sun is.

0:25:59.040 --> 0:26:00.600
<v Speaker 1>But that's where a lot of the light from the

0:26:00.600 --> 0:26:01.439
<v Speaker 1>Sun comes from.

0:26:01.680 --> 0:26:03.120
<v Speaker 2>Where does the other light come from.

0:26:03.200 --> 0:26:05.639
<v Speaker 1>The other light comes from specific atoms in the Sun

0:26:05.960 --> 0:26:09.159
<v Speaker 1>emitting light or absorbing that light. So I feel like

0:26:09.160 --> 0:26:11.560
<v Speaker 1>an oxygen atom in the atmosphere of the Sun and

0:26:11.640 --> 0:26:14.119
<v Speaker 1>it gets hot, its electrons jump up a couple of

0:26:14.240 --> 0:26:16.920
<v Speaker 1>energy levels, then they jump down, they relax, and they

0:26:16.920 --> 0:26:20.840
<v Speaker 1>emit a photon, and that photon it's very specific energy.

0:26:20.840 --> 0:26:24.399
<v Speaker 1>It corresponds to the difference in the energy levels of

0:26:24.400 --> 0:26:27.679
<v Speaker 1>that electron around the oxygen atom. Every atom out there

0:26:27.760 --> 0:26:31.480
<v Speaker 1>can emit an absorbed light in very specific wavelengths. So

0:26:31.520 --> 0:26:33.160
<v Speaker 1>if you look at the spectrum from the Sun, there's

0:26:33.200 --> 0:26:37.560
<v Speaker 1>this overall black body radiation, then these spikes where certain

0:26:37.600 --> 0:26:41.119
<v Speaker 1>atoms are emitting light that correspond to their energy levels

0:26:41.359 --> 0:26:44.760
<v Speaker 1>and their dips where other atoms are absorbing light that's

0:26:44.800 --> 0:26:47.080
<v Speaker 1>produced by the Sun at the energy levels that they

0:26:47.080 --> 0:26:49.280
<v Speaker 1>can do it. So you look at all those wiggles

0:26:49.280 --> 0:26:52.360
<v Speaker 1>in the spectrum and you can tell what's in the sun, or.

0:26:52.280 --> 0:26:54.879
<v Speaker 2>At least it seems like we thought we could. So

0:26:54.920 --> 0:26:56.720
<v Speaker 2>we did that for our sun, and we thought it

0:26:56.800 --> 0:26:58.840
<v Speaker 2>had a certain amount of metals in it. But then

0:26:58.880 --> 0:26:59.440
<v Speaker 2>what happened.

0:27:00.000 --> 0:27:02.040
<v Speaker 1>I thought, Okay, that's cool, one point eight percent. That

0:27:02.080 --> 0:27:04.720
<v Speaker 1>makes total sense. But then people thought, well, let's cross

0:27:04.760 --> 0:27:07.159
<v Speaker 1>check it. Let's see if we can measure what's in

0:27:07.160 --> 0:27:09.879
<v Speaker 1>the sun using another technique and come up with the

0:27:09.920 --> 0:27:12.240
<v Speaker 1>same answer. Another way to figure out what's in the

0:27:12.280 --> 0:27:15.320
<v Speaker 1>sun is to watch it boil is to like look

0:27:15.359 --> 0:27:18.439
<v Speaker 1>for waves in the surface of the Sun because that

0:27:18.440 --> 0:27:21.760
<v Speaker 1>tells you like how thick the sun is, the viscosity

0:27:21.800 --> 0:27:24.480
<v Speaker 1>of the Sun, which depends on what's in there, what's

0:27:24.480 --> 0:27:25.760
<v Speaker 1>sort of mucking around?

0:27:26.080 --> 0:27:27.919
<v Speaker 2>Wait, what what do you mean? Like as you look

0:27:27.960 --> 0:27:30.000
<v Speaker 2>at the surface of the Sun, you see it churning.

0:27:30.240 --> 0:27:33.399
<v Speaker 2>It's like super hot plasma, right mm hmm. And the

0:27:33.440 --> 0:27:37.719
<v Speaker 2>way the plasma churns tells you how goopy it is.

0:27:37.960 --> 0:27:41.280
<v Speaker 1>Yeah. They call it helio seismology, and it's sort of

0:27:41.280 --> 0:27:44.160
<v Speaker 1>similar to the way you can use earthquakes to understand

0:27:44.280 --> 0:27:46.920
<v Speaker 1>what the Earth is made out of. Like an earthquake

0:27:47.040 --> 0:27:49.879
<v Speaker 1>shakes the Earth, and then that shaking travels through the

0:27:49.920 --> 0:27:53.159
<v Speaker 1>Earth and it reflects at boundaries. Like that's how we

0:27:53.280 --> 0:27:56.280
<v Speaker 1>know where that boundary is between various layers of the Earth,

0:27:56.359 --> 0:27:58.600
<v Speaker 1>And we can also deduce things about like what's there

0:27:58.720 --> 0:28:01.840
<v Speaker 1>because how it bounces and reflects depends on the relative

0:28:01.880 --> 0:28:05.159
<v Speaker 1>density of things at those layers. So just by measuring

0:28:05.200 --> 0:28:07.640
<v Speaker 1>earthquakes at the surface, you can get a pretty good

0:28:07.640 --> 0:28:10.600
<v Speaker 1>picture for what's in the Earth. In the same way

0:28:10.680 --> 0:28:13.359
<v Speaker 1>we can look at ripples on the surface of the sun.

0:28:13.880 --> 0:28:17.280
<v Speaker 1>Helio seismology, they call it, to get a picture for

0:28:17.359 --> 0:28:18.480
<v Speaker 1>what's in the sun.

0:28:18.880 --> 0:28:21.760
<v Speaker 2>We don't have earthquake measuring devices on the sun. How

0:28:21.840 --> 0:28:24.840
<v Speaker 2>do we know the shaking of the surface of the sun.

0:28:25.320 --> 0:28:27.159
<v Speaker 1>So we don't need a complete picture of what's in

0:28:27.200 --> 0:28:29.720
<v Speaker 1>the sun. But we can watch waves move across the

0:28:29.760 --> 0:28:31.000
<v Speaker 1>surface of the sun. You know, we have a lot

0:28:31.000 --> 0:28:33.600
<v Speaker 1>of telescopes that can look at the Sun and they

0:28:33.600 --> 0:28:36.000
<v Speaker 1>can see the behavior and the churning on the surface,

0:28:36.440 --> 0:28:38.479
<v Speaker 1>and there's a lot of stuff going on there. But

0:28:38.520 --> 0:28:40.440
<v Speaker 1>we only need a sort of rough picture of what's

0:28:40.440 --> 0:28:42.920
<v Speaker 1>in the sun because it turns out this one very

0:28:42.960 --> 0:28:46.120
<v Speaker 1>particular thing that's controlled by the metals that we're trying

0:28:46.120 --> 0:28:48.320
<v Speaker 1>to get a sense of. It's a balance between two

0:28:48.440 --> 0:28:51.240
<v Speaker 1>processes that are trying to move the heat out of

0:28:51.280 --> 0:28:53.720
<v Speaker 1>the sun. The sun has sort of two parts to it.

0:28:53.720 --> 0:28:56.440
<v Speaker 1>It's like the outermost part and the innermost part. And

0:28:56.520 --> 0:28:58.959
<v Speaker 1>the innermost part a lot of heat is being created

0:28:58.960 --> 0:29:02.160
<v Speaker 1>it's radiating out, so that radiation comes out from the

0:29:02.160 --> 0:29:05.040
<v Speaker 1>core and hits the outer part of the sun. But

0:29:05.160 --> 0:29:07.240
<v Speaker 1>that outer part can be kind of opaque because of

0:29:07.320 --> 0:29:11.320
<v Speaker 1>like oxygen or heavy elements can absorb those photons. So

0:29:11.360 --> 0:29:14.560
<v Speaker 1>that means that that energy can't be radiated out from

0:29:14.600 --> 0:29:16.800
<v Speaker 1>the core of the Sun. Instead, you need to get

0:29:16.800 --> 0:29:20.520
<v Speaker 1>that energy out using another method we call convection, basically

0:29:20.600 --> 0:29:23.240
<v Speaker 1>just like hot stuff rising up the way it does

0:29:23.280 --> 0:29:25.480
<v Speaker 1>in a pot of water. So there's sort of two

0:29:25.560 --> 0:29:28.080
<v Speaker 1>parts of the Sun, one where photons can bring the

0:29:28.160 --> 0:29:30.200
<v Speaker 1>energy out and the other where we have to rely

0:29:30.360 --> 0:29:33.480
<v Speaker 1>on convection. And there's a boundary between these two regions,

0:29:33.720 --> 0:29:36.200
<v Speaker 1>and that depends a lot on like how much oxygen

0:29:36.360 --> 0:29:38.280
<v Speaker 1>is there in the Sun, and that's what we're trying

0:29:38.280 --> 0:29:41.280
<v Speaker 1>to measure with this helio seismology. We're trying to figure out,

0:29:41.280 --> 0:29:44.200
<v Speaker 1>like where's the threshold between these two parts of the

0:29:44.240 --> 0:29:45.200
<v Speaker 1>inside of the sun.

0:29:45.400 --> 0:29:48.240
<v Speaker 2>And we do this by just looking at the flow

0:29:48.840 --> 0:29:51.040
<v Speaker 2>that you can see in the picture of the sun.

0:29:51.160 --> 0:29:53.400
<v Speaker 2>Or do we have like an X ray way to

0:29:53.440 --> 0:29:54.360
<v Speaker 2>look inside the sun.

0:29:54.520 --> 0:29:56.920
<v Speaker 1>No, we have no X ray. Unfortunately, it's just effectively

0:29:57.040 --> 0:30:00.520
<v Speaker 1>sound waves in the sun. And of course nobody's hearing

0:30:00.560 --> 0:30:02.760
<v Speaker 1>these things. When we say sound waves, we just mean

0:30:02.760 --> 0:30:05.360
<v Speaker 1>pressure waves moving through the Sun, but just the same

0:30:05.400 --> 0:30:08.480
<v Speaker 1>way that earthquakes make effectively sound waves through the Earth,

0:30:08.720 --> 0:30:11.320
<v Speaker 1>and you can listen to the earth ringing just by

0:30:11.320 --> 0:30:13.960
<v Speaker 1>seeing the Earth shake. If we watch the surface of

0:30:14.000 --> 0:30:16.600
<v Speaker 1>the Sun, we don't have like instruments on the surface

0:30:16.640 --> 0:30:19.280
<v Speaker 1>that measure the actual shaking, but you can see these

0:30:19.400 --> 0:30:22.720
<v Speaker 1>ripples in the plasma on the surface. You can effectively

0:30:22.800 --> 0:30:26.480
<v Speaker 1>see sound moving through the Sun and bouncing back. And

0:30:26.560 --> 0:30:29.160
<v Speaker 1>this boundary between the two parts of the Sun, one

0:30:29.160 --> 0:30:31.920
<v Speaker 1>that's opaque to photons and one that isn't shows up

0:30:31.960 --> 0:30:34.360
<v Speaker 1>as like a glitch in the sound waves. It changes

0:30:34.400 --> 0:30:36.560
<v Speaker 1>how those sound waves move through the Sun.

0:30:37.240 --> 0:30:39.480
<v Speaker 2>Well, wait, are you saying there's sort of like two

0:30:39.720 --> 0:30:41.760
<v Speaker 2>kinds of sun surfaces.

0:30:42.000 --> 0:30:44.200
<v Speaker 1>Yeah, there's like a surface within the surface, the same

0:30:44.240 --> 0:30:46.840
<v Speaker 1>way that like the Earth has multiple layers to it.

0:30:46.880 --> 0:30:48.720
<v Speaker 1>You know, it's the mantle and the outer core and

0:30:48.760 --> 0:30:51.520
<v Speaker 1>the inner core, et cetera. The Sun also has these

0:30:51.560 --> 0:30:55.200
<v Speaker 1>regions and there's this boundary. They think it's like seventy

0:30:55.320 --> 0:30:58.720
<v Speaker 1>ish percent of the solar radius. Within that photons can

0:30:58.800 --> 0:31:01.920
<v Speaker 1>like fly free, and you this radiative transfer where photons

0:31:01.920 --> 0:31:05.040
<v Speaker 1>can move heat out from the center. The outer part

0:31:05.080 --> 0:31:08.040
<v Speaker 1>is more opake and photons can't really get through it.

0:31:08.040 --> 0:31:09.880
<v Speaker 1>It's the only way to get heat out from the Sun.

0:31:09.920 --> 0:31:13.520
<v Speaker 1>There is more like convection like hot gas rising up.

0:31:13.760 --> 0:31:15.600
<v Speaker 2>But then what are you basically saying that looking at

0:31:15.600 --> 0:31:18.200
<v Speaker 2>these sound waves tells us a different number for what

0:31:18.280 --> 0:31:19.200
<v Speaker 2>the Sun is made out of.

0:31:19.440 --> 0:31:22.080
<v Speaker 1>Exactly, looking at the sound waves tells us something about

0:31:22.120 --> 0:31:24.600
<v Speaker 1>where this balance is between the two different parts of

0:31:24.600 --> 0:31:27.320
<v Speaker 1>the Sun, and that depends on how much metal is

0:31:27.360 --> 0:31:30.360
<v Speaker 1>in the Sun, because the metallicity of the Sun controls

0:31:30.400 --> 0:31:34.440
<v Speaker 1>whether it's opaque or transparent. You have more oxygen, more carbon,

0:31:34.520 --> 0:31:38.440
<v Speaker 1>more neon. That makes the Sun more opaque, which changes

0:31:38.480 --> 0:31:41.040
<v Speaker 1>how far the photons can get. So if we can

0:31:41.160 --> 0:31:43.600
<v Speaker 1>use sound waves on the surface of the Sun figure

0:31:43.600 --> 0:31:47.160
<v Speaker 1>out where is this transition within the Sun between opaque

0:31:47.280 --> 0:31:50.160
<v Speaker 1>and transparent to these photons, then we could figure out

0:31:50.400 --> 0:31:53.040
<v Speaker 1>how much metal is in the Sun because the metallicity

0:31:53.120 --> 0:31:55.360
<v Speaker 1>controls where that transition is.

0:31:55.640 --> 0:31:57.720
<v Speaker 2>But then why do metals make the Sun more opake?

0:31:58.040 --> 0:32:00.560
<v Speaker 1>These heavy elements like oxygen, they like to absorb these

0:32:00.560 --> 0:32:04.280
<v Speaker 1>photons like more than hydrogen, Yeah, more than hydrogen. You know,

0:32:04.320 --> 0:32:06.959
<v Speaker 1>every atom likes to absorb photons of a certain energy,

0:32:07.240 --> 0:32:09.080
<v Speaker 1>and so the kinds of energy that tend to be

0:32:09.080 --> 0:32:11.719
<v Speaker 1>produced in fusion tend to also be the kind that

0:32:11.800 --> 0:32:15.000
<v Speaker 1>oxygen likes to gobble up. For example. So if you

0:32:15.000 --> 0:32:17.600
<v Speaker 1>do all these calculations, you figure out, well, where is

0:32:17.680 --> 0:32:20.400
<v Speaker 1>this threshold where's the sun become opaque inside of it?

0:32:20.720 --> 0:32:22.880
<v Speaker 1>And what does that mean about the amount of metal

0:32:22.920 --> 0:32:26.000
<v Speaker 1>inside the sun? You get a different number. So from

0:32:26.080 --> 0:32:28.760
<v Speaker 1>helio seismology, from these sound waves, we get the number

0:32:28.760 --> 0:32:31.600
<v Speaker 1>one point eight percent. Whereas we look at the spectrum

0:32:31.640 --> 0:32:33.520
<v Speaker 1>of light from the sun, we got the number one

0:32:33.520 --> 0:32:36.520
<v Speaker 1>point three percent. So we thought, oh, this would be

0:32:36.520 --> 0:32:38.440
<v Speaker 1>a great way to cross check and to just make

0:32:38.480 --> 0:32:40.280
<v Speaker 1>sure we understand what's in the sun. And then it

0:32:40.320 --> 0:32:42.800
<v Speaker 1>turns out, oops, the numbers don't agree.

0:32:43.040 --> 0:32:45.920
<v Speaker 2>Now is that do you think maybe because looking at

0:32:45.960 --> 0:32:47.760
<v Speaker 2>the spectrum of the sun only kind of maybe tells

0:32:47.800 --> 0:32:49.280
<v Speaker 2>you what's in the surface of the sun.

0:32:49.560 --> 0:32:51.400
<v Speaker 1>It is possible, but they've accounted for that. They have

0:32:51.480 --> 0:32:54.280
<v Speaker 1>models for where these things are distributed in the sun

0:32:54.320 --> 0:32:57.200
<v Speaker 1>and how much they would radiate. So there are definitely

0:32:57.280 --> 0:32:59.760
<v Speaker 1>questions there and things people are trying to drill down on,

0:33:00.080 --> 0:33:01.680
<v Speaker 1>but they do think they've accounted for that.

0:33:02.600 --> 0:33:04.360
<v Speaker 2>But the second one of the ways seems a little

0:33:04.400 --> 0:33:08.840
<v Speaker 2>a bit more circumspect, I guess, or more indirect than

0:33:08.960 --> 0:33:10.760
<v Speaker 2>actually just looking at the light from the sun.

0:33:11.760 --> 0:33:14.120
<v Speaker 1>It does in the end, we're always just getting information

0:33:14.200 --> 0:33:16.240
<v Speaker 1>from far away and using that to try to infer

0:33:16.320 --> 0:33:18.800
<v Speaker 1>what's going on, and what's happening here is something I

0:33:18.880 --> 0:33:20.959
<v Speaker 1>love in science. It's like, well, let's cross check our

0:33:21.040 --> 0:33:23.880
<v Speaker 1>understanding by seeing if we could do this two different ways,

0:33:24.160 --> 0:33:26.920
<v Speaker 1>making different assumptions, or probing our model in different ways

0:33:26.960 --> 0:33:30.040
<v Speaker 1>to see whether it breaks. And this kind of detailed

0:33:30.080 --> 0:33:32.600
<v Speaker 1>work has led to crazy discoveries in the past. You know,

0:33:32.920 --> 0:33:35.800
<v Speaker 1>when we, for example, predicted how many neutrinos would be

0:33:35.800 --> 0:33:37.880
<v Speaker 1>coming from the sun versus how many new trinos we

0:33:37.920 --> 0:33:40.000
<v Speaker 1>saw from the sun, and we saw a huge difference.

0:33:40.400 --> 0:33:44.400
<v Speaker 1>That led to understanding neutrino oscillations and neutrino masses. So

0:33:44.600 --> 0:33:46.600
<v Speaker 1>not every way is going to be as precise, but

0:33:46.640 --> 0:33:48.560
<v Speaker 1>it's important to have different ways to cross check each

0:33:48.560 --> 0:33:50.600
<v Speaker 1>other and to try to get some hints about what's

0:33:50.640 --> 0:33:52.120
<v Speaker 1>really going on inside the sun.

0:33:52.680 --> 0:33:55.120
<v Speaker 2>Well, it sounds like we've measured how much metal is

0:33:55.120 --> 0:33:57.400
<v Speaker 2>in the sun in two different ways and they disagree

0:33:57.880 --> 0:34:00.920
<v Speaker 2>by a pretty big amount, and so let's get into

0:34:00.960 --> 0:34:04.160
<v Speaker 2>what the difference means, who's right, who's wrong, and how

0:34:04.200 --> 0:34:06.760
<v Speaker 2>metal is the sun. So let's dig into that. But

0:34:06.800 --> 0:34:21.840
<v Speaker 2>first let's take another quick break. All right, we're asking

0:34:21.880 --> 0:34:24.040
<v Speaker 2>how much metal is in the sun, and it sounds

0:34:24.040 --> 0:34:27.200
<v Speaker 2>like we have two answers. One way, by looking at

0:34:27.200 --> 0:34:29.879
<v Speaker 2>the light from the sun tells us that it's one

0:34:29.880 --> 0:34:33.560
<v Speaker 2>point three percent non hydrogen and helium. But looking at

0:34:33.600 --> 0:34:37.560
<v Speaker 2>the flow of the plasma and how the sound ways

0:34:37.600 --> 0:34:39.920
<v Speaker 2>travel across the surface of the Sun, that tells us

0:34:39.920 --> 0:34:42.920
<v Speaker 2>that maybe the sun is one point eight percent non

0:34:43.239 --> 0:34:46.439
<v Speaker 2>hydrogen and helium. So who's right and who's wrong.

0:34:47.520 --> 0:34:50.560
<v Speaker 1>We don't know yet, But we have a third answer.

0:34:51.000 --> 0:34:53.440
<v Speaker 1>People came up with yet another way to try to

0:34:53.440 --> 0:34:54.600
<v Speaker 1>figure out how much.

0:34:54.480 --> 0:34:56.839
<v Speaker 2>Metal is in the sun, just asking the sun.

0:34:58.160 --> 0:35:00.560
<v Speaker 1>Nobody thought of that. Oh my god, you know, if

0:35:00.600 --> 0:35:02.359
<v Speaker 1>the Sun really isn't a rock band, it's gonna love

0:35:02.400 --> 0:35:06.480
<v Speaker 1>doing interviews. But this third way actually does use neutrinos,

0:35:06.880 --> 0:35:09.520
<v Speaker 1>because fusion at the heart of the Sun produces vast,

0:35:09.600 --> 0:35:13.960
<v Speaker 1>vast quantities of neutrinos, these tiny, little ghostly particles that

0:35:14.000 --> 0:35:16.560
<v Speaker 1>are everwhere, but we can't feel them because they only

0:35:16.600 --> 0:35:19.480
<v Speaker 1>have weak interactions. They have no electric charge, they have

0:35:19.520 --> 0:35:23.120
<v Speaker 1>no strong force charge. They're very difficult to spot. But

0:35:23.160 --> 0:35:26.399
<v Speaker 1>we have technologies neutrino eyeballs, we've invented to be able

0:35:26.400 --> 0:35:28.759
<v Speaker 1>to pick out a few of these neutrinos. We can

0:35:28.880 --> 0:35:32.960
<v Speaker 1>also measure the energy of those neutrinos. And the neutrinos

0:35:32.960 --> 0:35:36.080
<v Speaker 1>are produced by fusion in the sun, and how much

0:35:36.160 --> 0:35:38.600
<v Speaker 1>metal you have in the sun affects the rate at

0:35:38.640 --> 0:35:41.759
<v Speaker 1>which that fusion happens and also affects the energy of

0:35:41.800 --> 0:35:45.719
<v Speaker 1>the neutrinos that's produced. We're trying to fuse protons and

0:35:45.760 --> 0:35:48.320
<v Speaker 1>protons together. If there's a bunch of heavy metal around

0:35:48.320 --> 0:35:51.640
<v Speaker 1>that actually interferes with the fusion, makes it less likely,

0:35:51.680 --> 0:35:54.080
<v Speaker 1>it makes it more important to have higher energy on

0:35:54.120 --> 0:35:58.280
<v Speaker 1>those protons, etc. So the neutrino energy spectrum you expect

0:35:58.480 --> 0:36:01.200
<v Speaker 1>depends on how much metal in the sun, but it's

0:36:01.239 --> 0:36:03.200
<v Speaker 1>a bit of a weak effect. It's not a very

0:36:03.239 --> 0:36:05.360
<v Speaker 1>strong way to measure this quantity.

0:36:05.560 --> 0:36:07.600
<v Speaker 2>Well, also, what do you compare it to, like, how

0:36:07.640 --> 0:36:10.239
<v Speaker 2>do you know what the right amount of neutrinos should

0:36:10.280 --> 0:36:11.960
<v Speaker 2>be for a certain amount of metals.

0:36:12.320 --> 0:36:15.480
<v Speaker 1>Yeah, great question. We have a really detailed model of

0:36:15.520 --> 0:36:18.680
<v Speaker 1>the fusion and how it produces neutrinos, and that's been

0:36:18.680 --> 0:36:21.359
<v Speaker 1>the subject of decades of study, and of course, first

0:36:21.400 --> 0:36:24.280
<v Speaker 1>there were big mysteries we predicted a huge amount of neutrinos,

0:36:24.280 --> 0:36:26.480
<v Speaker 1>we only saw a third of them. Later we discovered

0:36:26.520 --> 0:36:29.279
<v Speaker 1>that's because those neutrinos are changing into another kind of

0:36:29.360 --> 0:36:32.480
<v Speaker 1>neutrino as they travel through space. Check out our episode

0:36:32.480 --> 0:36:35.000
<v Speaker 1>on neutrino oscillation if you want to understand that more.

0:36:35.440 --> 0:36:37.800
<v Speaker 1>But yeah, there are definitely uncertainties there. These are models

0:36:37.840 --> 0:36:40.040
<v Speaker 1>we have of how the diffusion is happening and how

0:36:40.080 --> 0:36:42.640
<v Speaker 1>the neutrinos are being created, So we don't have an

0:36:42.640 --> 0:36:45.600
<v Speaker 1>absolute calibration of that either. We just have these calculations

0:36:45.640 --> 0:36:49.000
<v Speaker 1>we've done that predict the spectrum, and then those calculations

0:36:49.040 --> 0:36:51.640
<v Speaker 1>depend also on the metal. So you tweak the metals up,

0:36:51.680 --> 0:36:53.480
<v Speaker 1>you get one spectrum. You tweak the metals down, you

0:36:53.520 --> 0:36:55.920
<v Speaker 1>get another spectrum. So we can tweak the amount of

0:36:55.920 --> 0:36:58.680
<v Speaker 1>metals we put into these calculations to match what we see,

0:36:58.920 --> 0:37:01.000
<v Speaker 1>and then we think, well, let's the most likely value

0:37:01.000 --> 0:37:02.080
<v Speaker 1>of the metal in the sun.

0:37:03.280 --> 0:37:05.880
<v Speaker 2>So then what does this neutrino method say about the

0:37:05.920 --> 0:37:06.680
<v Speaker 2>metals in the sun.

0:37:06.880 --> 0:37:10.640
<v Speaker 1>So unfortunately, this method isn't super precise. It slightly favors

0:37:10.880 --> 0:37:13.680
<v Speaker 1>the higher metal scenario, so like one point eight percent,

0:37:13.920 --> 0:37:15.920
<v Speaker 1>but it can't rule out the one point three percent.

0:37:15.920 --> 0:37:18.080
<v Speaker 1>It's just sort of more like a hint. It's a

0:37:18.120 --> 0:37:19.880
<v Speaker 1>little bit of a vote towards heavy metals.

0:37:21.280 --> 0:37:25.440
<v Speaker 2>So then we have three competing methods and they all

0:37:25.480 --> 0:37:28.120
<v Speaker 2>say something slightly different. How are we going to figure

0:37:28.120 --> 0:37:28.879
<v Speaker 2>out which one's right.

0:37:28.880 --> 0:37:31.320
<v Speaker 1>We're going to dig in and question all of our assumptions,

0:37:31.400 --> 0:37:34.160
<v Speaker 1>understand where we might have overlooked something. We're going to

0:37:34.239 --> 0:37:39.200
<v Speaker 1>do more experiments, collect more data, these neutrino experiments. Specifically,

0:37:39.320 --> 0:37:41.160
<v Speaker 1>this is sort of like the first run, the first

0:37:41.200 --> 0:37:43.960
<v Speaker 1>gasp of the data. As that runs longer and longer,

0:37:43.960 --> 0:37:46.520
<v Speaker 1>it little bit more and more precise and maybe sharpen

0:37:46.600 --> 0:37:49.440
<v Speaker 1>our understanding. But this is really crucial that we figure

0:37:49.440 --> 0:37:51.040
<v Speaker 1>this out because the Sun is sort of like our

0:37:51.160 --> 0:37:54.440
<v Speaker 1>yardstick for the rest of the universe. For other stars,

0:37:54.480 --> 0:37:56.640
<v Speaker 1>we have no hope. But like looking at sound waves

0:37:56.640 --> 0:37:58.520
<v Speaker 1>on the surface, we can only look at the light

0:37:58.560 --> 0:38:01.480
<v Speaker 1>from those stars. Compare the light from those stars to

0:38:01.520 --> 0:38:03.680
<v Speaker 1>the light we get from the Sun, and we use

0:38:03.719 --> 0:38:06.239
<v Speaker 1>that to infer what's in them. Our whole estimate for

0:38:06.280 --> 0:38:09.040
<v Speaker 1>what's out there in the universe is based on what's

0:38:09.120 --> 0:38:11.200
<v Speaker 1>in the sun. If we were wrong about what's in

0:38:11.200 --> 0:38:14.080
<v Speaker 1>the sun, then we were wrong about the whole universe.

0:38:14.360 --> 0:38:16.640
<v Speaker 2>Well, unless it turns out that these other ways to

0:38:16.680 --> 0:38:19.680
<v Speaker 2>measure what's in the sun are wrong, and maybe the

0:38:19.800 --> 0:38:22.439
<v Speaker 2>one that you can't apply to other stars is right.

0:38:22.920 --> 0:38:25.319
<v Speaker 1>Yeah, absolutely, it could be, or it could be that

0:38:25.360 --> 0:38:27.480
<v Speaker 1>we don't understand what's inside the sun and how this

0:38:27.520 --> 0:38:30.839
<v Speaker 1>all works, and they're both wrong. Either way, we'd love

0:38:30.880 --> 0:38:33.160
<v Speaker 1>to understand better what's in the sun because it helps

0:38:33.239 --> 0:38:35.719
<v Speaker 1>us understand what's out there in the universe. It also

0:38:35.800 --> 0:38:38.920
<v Speaker 1>really helps us understand the fate of all of those stars.

0:38:39.400 --> 0:38:42.400
<v Speaker 1>Even though the stars are mostly not metal, those metals

0:38:42.440 --> 0:38:45.680
<v Speaker 1>can really influence whether those stars have planets around them,

0:38:45.880 --> 0:38:48.560
<v Speaker 1>how long those stars will live, and how they will die.

0:38:48.920 --> 0:38:52.719
<v Speaker 2>Ooh wait, what's the connection between the metals in the

0:38:52.760 --> 0:38:54.200
<v Speaker 2>star and their planets?

0:38:54.600 --> 0:38:56.799
<v Speaker 1>I knew you wanted to talk about aliens, right.

0:38:56.680 --> 0:38:58.399
<v Speaker 2>No, No, I just ask about the planets. I didn't

0:38:58.400 --> 0:39:01.600
<v Speaker 2>say anything about aliens. Don't protect your alien fetish on me.

0:39:01.719 --> 0:39:05.680
<v Speaker 1>Man, Who do you think is living on those planets? Man?

0:39:06.160 --> 0:39:11.560
<v Speaker 2>Nobody? Maybe alg plants heavy metal bands. Nobody said anything

0:39:11.560 --> 0:39:13.040
<v Speaker 2>about aliens. Daniels, All right, well.

0:39:12.960 --> 0:39:15.960
<v Speaker 1>I'm about to okay, get ready, Well, the more metal

0:39:15.960 --> 0:39:19.200
<v Speaker 1>there is in the initial cloud that forms that solar system.

0:39:19.320 --> 0:39:21.600
<v Speaker 1>The more metal there's going to be for making planets,

0:39:22.040 --> 0:39:23.880
<v Speaker 1>and the more metal there is, the more likely you

0:39:23.920 --> 0:39:27.239
<v Speaker 1>are to seed something that's not just the star. You

0:39:27.280 --> 0:39:29.640
<v Speaker 1>have this huge collapse in cloud. Why doesn't it all

0:39:29.760 --> 0:39:32.960
<v Speaker 1>just become a star? If some little seed near the

0:39:33.000 --> 0:39:35.600
<v Speaker 1>star can form fast enough to make its own little

0:39:35.600 --> 0:39:38.520
<v Speaker 1>gravitational well, it can gather up a bunch of stuff

0:39:38.640 --> 0:39:41.160
<v Speaker 1>and get into orbit and avoid collapsing into the star.

0:39:41.640 --> 0:39:44.120
<v Speaker 1>Do that you need a little density seed. And so

0:39:44.600 --> 0:39:47.560
<v Speaker 1>stars with more metal in them tend to have more

0:39:47.640 --> 0:39:51.200
<v Speaker 1>planets around them as well, rocky planets and giant.

0:39:50.800 --> 0:39:53.279
<v Speaker 2>Planets, we think, or we know this for sure, Like,

0:39:53.320 --> 0:39:54.880
<v Speaker 2>have we measured this out there?

0:39:55.000 --> 0:39:57.399
<v Speaker 1>We've measured this out there because we've seen planets around

0:39:57.480 --> 0:40:00.800
<v Speaker 1>other stars and so we've seen this correlation. Stars whose

0:40:00.880 --> 0:40:04.080
<v Speaker 1>light indicates more metal in them also tend to have

0:40:04.120 --> 0:40:05.359
<v Speaker 1>more planets around them.

0:40:05.440 --> 0:40:11.040
<v Speaker 2>So there's a correlation between melicity and number of planets potentially.

0:40:10.600 --> 0:40:12.560
<v Speaker 1>No, that's something we've measured. Of course, we have a

0:40:12.560 --> 0:40:14.919
<v Speaker 1>biased view of all the planets out there. We can't

0:40:14.920 --> 0:40:17.000
<v Speaker 1>see all the kinds of planets. We're not great at

0:40:17.000 --> 0:40:19.840
<v Speaker 1>seeing some kinds of planets. We can only see planets

0:40:19.880 --> 0:40:22.440
<v Speaker 1>under certain conditions, et cetera, et cetera. So this is

0:40:22.440 --> 0:40:24.279
<v Speaker 1>sort of an initial thing, but it's a correlation that

0:40:24.280 --> 0:40:26.640
<v Speaker 1>we've noticed and also one that makes sense. Right, it

0:40:26.680 --> 0:40:29.200
<v Speaker 1>fits in with our model for householar systems form.

0:40:29.480 --> 0:40:31.160
<v Speaker 2>All right, Well, I guess how are we going to

0:40:31.239 --> 0:40:33.839
<v Speaker 2>figure out what's in our sun? Then? Is there going

0:40:33.880 --> 0:40:35.960
<v Speaker 2>to be a conclusive proof at some point? Like are

0:40:35.960 --> 0:40:37.759
<v Speaker 2>we going to be able to maybe dip into the

0:40:37.800 --> 0:40:39.000
<v Speaker 2>sun and get a scoop of it?

0:40:40.080 --> 0:40:42.080
<v Speaker 1>That would be awesome. We were thinking about sending your

0:40:42.160 --> 0:40:44.520
<v Speaker 1>band over to visit the sun. Are you guys available?

0:40:45.000 --> 0:40:45.720
<v Speaker 1>Who's your agent?

0:40:46.000 --> 0:40:48.880
<v Speaker 2>Well, it depends how much are you paying and what's

0:40:48.920 --> 0:40:52.799
<v Speaker 2>the budget. Will there be green Eminem's in the green room?

0:40:53.320 --> 0:40:55.319
<v Speaker 1>I thought it was brown Eminem's in the green room?

0:40:55.480 --> 0:40:56.960
<v Speaker 2>Well, I mean, I think the whole point is that

0:40:57.000 --> 0:40:58.799
<v Speaker 2>we get to choose what kind of mmms are in

0:40:58.840 --> 0:41:01.800
<v Speaker 2>the waiting room.

0:41:01.840 --> 0:41:04.400
<v Speaker 1>All right, we'll work on the budget, but this is

0:41:04.440 --> 0:41:07.520
<v Speaker 1>not something that we are likely to figure out directly.

0:41:07.800 --> 0:41:10.240
<v Speaker 1>It's always going to be a game of improving our models,

0:41:10.520 --> 0:41:13.200
<v Speaker 1>comparing the model's predictions to what we see out there

0:41:13.200 --> 0:41:15.400
<v Speaker 1>in the universe and then seeing if we get it

0:41:15.400 --> 0:41:17.160
<v Speaker 1>to tell a coherent story.

0:41:17.239 --> 0:41:19.799
<v Speaker 2>Can we send something into the sun, like have something

0:41:19.840 --> 0:41:21.799
<v Speaker 2>fall into the Sun, and as it falls and gets

0:41:21.880 --> 0:41:23.640
<v Speaker 2>destroyed and maybe tells us what's in the.

0:41:23.600 --> 0:41:27.200
<v Speaker 1>Sun potentially with some technological advances. As I know, you know,

0:41:27.520 --> 0:41:30.400
<v Speaker 1>our recent Parker solar probe got pretty close to the

0:41:30.400 --> 0:41:33.080
<v Speaker 1>Sun but almost got toasted. It's very difficult to even

0:41:33.120 --> 0:41:35.719
<v Speaker 1>get that close to the Sun, and it was nowhere

0:41:35.960 --> 0:41:39.839
<v Speaker 1>near being able to actually sample something. On the other hand,

0:41:39.880 --> 0:41:42.480
<v Speaker 1>we're sort of already in the Sun in one sense

0:41:42.880 --> 0:41:45.160
<v Speaker 1>because where it is the edge of the Sun, the

0:41:45.200 --> 0:41:47.000
<v Speaker 1>Sun starts out very dense and then gets more and

0:41:47.040 --> 0:41:50.160
<v Speaker 1>more dilute. Then it's got this huge extended corona and

0:41:50.200 --> 0:41:52.960
<v Speaker 1>the wind. So we're already sort of sampling stuff from

0:41:52.960 --> 0:41:55.560
<v Speaker 1>the Sun. So it's possible that like the solar wind

0:41:55.600 --> 0:41:58.520
<v Speaker 1>itself might have clues we can use to figure out

0:41:58.760 --> 0:42:02.280
<v Speaker 1>what's in the Sun. Energy of those particles could potentially

0:42:02.320 --> 0:42:04.799
<v Speaker 1>be sensitive to the metallicity of the Sun.

0:42:05.600 --> 0:42:08.160
<v Speaker 2>Well, it's kind of interesting that, like we only have

0:42:08.239 --> 0:42:11.080
<v Speaker 2>one star close to us, we be able to run

0:42:11.120 --> 0:42:14.040
<v Speaker 2>these experiments and verify our models of what goes on

0:42:14.160 --> 0:42:16.799
<v Speaker 2>in any star, and so we're sort of hoping that

0:42:16.880 --> 0:42:19.640
<v Speaker 2>our Sun is not super atypical or weird.

0:42:19.880 --> 0:42:22.560
<v Speaker 1>Yeah, exactly, And we know that our star is unusual

0:42:22.560 --> 0:42:25.000
<v Speaker 1>in some sense. It's more massive than your typical star.

0:42:25.360 --> 0:42:27.880
<v Speaker 1>Most of the stars out there are red dwarfs. But

0:42:27.920 --> 0:42:30.680
<v Speaker 1>it's also in the sort of unusually good position to

0:42:30.719 --> 0:42:33.439
<v Speaker 1>sample the average kind of stuff. In the Milky Way.

0:42:33.760 --> 0:42:36.480
<v Speaker 1>We're like halfway from the Milky Way center to the

0:42:36.680 --> 0:42:39.680
<v Speaker 1>edge of the disk of stars, and most stars out

0:42:39.680 --> 0:42:42.040
<v Speaker 1>there in the universe are in big galaxies like the

0:42:42.080 --> 0:42:44.520
<v Speaker 1>Milky Way, So the Sun is sort of a scoop

0:42:44.560 --> 0:42:47.759
<v Speaker 1>of typical material, we think, so understanding what's in the

0:42:47.800 --> 0:42:51.240
<v Speaker 1>Sun will really help us understand what's in the universe.

0:42:51.080 --> 0:42:56.120
<v Speaker 2>And how heavy metal aliens might be. Isn't that the

0:42:56.120 --> 0:42:58.080
<v Speaker 2>whole point of this episode, Daniel.

0:42:58.000 --> 0:43:00.319
<v Speaker 1>Yes, exactly. We were just working up to that one

0:43:00.400 --> 0:43:01.240
<v Speaker 1>joke the whole.

0:43:01.000 --> 0:43:06.920
<v Speaker 2>Time, all right. Well, another example of how there are

0:43:07.000 --> 0:43:10.360
<v Speaker 2>still big mystories. Even in our own heart of the

0:43:10.440 --> 0:43:13.960
<v Speaker 2>Solar system, the Sun, we sort of don't really know

0:43:14.120 --> 0:43:17.399
<v Speaker 2>what it's actually made out of, and even though it's

0:43:17.400 --> 0:43:20.720
<v Speaker 2>so close we can actually go in there and figure

0:43:20.760 --> 0:43:23.000
<v Speaker 2>it out ourselves directly. We have to find all these

0:43:23.040 --> 0:43:26.480
<v Speaker 2>clever ways to infer what's inside the sun, and.

0:43:26.520 --> 0:43:30.040
<v Speaker 1>These basic questions about what's in our own backyard, in fact,

0:43:30.040 --> 0:43:32.319
<v Speaker 1>the whole universe. They tell us what's likely to be

0:43:32.400 --> 0:43:35.480
<v Speaker 1>out there in the universe, and also how it all

0:43:35.520 --> 0:43:39.160
<v Speaker 1>will end. Stars with more metallinem are more likely to

0:43:39.239 --> 0:43:42.279
<v Speaker 1>form neutron stars rather than black holes, and so the

0:43:42.320 --> 0:43:44.520
<v Speaker 1>fate of all those stars we see up there in

0:43:44.520 --> 0:43:47.359
<v Speaker 1>the night sky could depend on these measurements of what's

0:43:47.400 --> 0:43:48.520
<v Speaker 1>in our backyard.

0:43:48.840 --> 0:43:52.160
<v Speaker 2>We hope you enjoyed that. Thanks for joining us, See

0:43:52.160 --> 0:43:52.600
<v Speaker 2>you next tent.

0:43:57.440 --> 0:44:00.640
<v Speaker 1>For more science and curiosity, come find us on social media,

0:44:00.719 --> 0:44:05.240
<v Speaker 1>where we answer questions and post videos. We're on Twitter, Discorg, Insta,

0:44:05.360 --> 0:44:09.080
<v Speaker 1>and now TikTok. Thanks for listening, and remember that Daniel

0:44:09.080 --> 0:44:12.560
<v Speaker 1>and Jorge Explain the Universe is a production of iHeartRadio.

0:44:12.840 --> 0:44:18.000
<v Speaker 1>For more podcasts from iHeartRadio, visit the iHeartRadio app, Apple Podcasts,

0:44:18.080 --> 0:44:20.440
<v Speaker 1>or wherever you listen to your favorite shows.