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Speaker 1: Hey, Orge, are you preparing your kids for when the

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Speaker 1: end times come?

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Speaker 2: Oh?

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Speaker 3: You mean when bananas go extinct? Or do you mean

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Speaker 3: when I retire?

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Speaker 1: Yeah, I mean the fall of civilization, when we're all

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Speaker 1: listening to podcast in our caves.

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Speaker 3: I feel like I've been preparing my whole life. If

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Speaker 3: there's a post apocalyptic movie out there, I probably see it.

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Speaker 1: Well, then I hope you're teaching your kids some useful skills,

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Speaker 1: you know, blacksmithing, martial arts, cartooning.

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Speaker 3: Oh yeah, cartooning for sure, that's going to come in handy.

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Speaker 3: But you don't think they should learn a particle physics.

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Speaker 1: I don't know that anybody's going to be building colliders

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Speaker 1: out of sticks and rocks.

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Speaker 3: Isn't it fire? Doesn't it fire evolve particles colliding?

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Speaker 1: A fire is kind of a chemical accelerator. I suppose

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Speaker 1: there must be some collisions, or.

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Speaker 3: Are you going to be like, you know, freezing out there,

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Speaker 3: and you're gonna be like, oh no, no, sorry, the

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Speaker 3: fire is just not fundamental.

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Speaker 1: Enough for me. I think I would be hiding in

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Speaker 1: my cave eating the last of the world's chocolate reserves.

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Speaker 3: Who would that be a useful skill? You could be

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Speaker 3: it the world's only chocolate tear. Hopefully the zombies like chocolate.

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Speaker 1: Dark chocolate is the world's final currency.

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Speaker 3: I am Poorge, my corctoonist and the author of Oliver's

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Speaker 3: Great Big Universe.

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

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Speaker 1: at UC Irvine, and I purposely got into particle physics

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Speaker 1: because it was useless.

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Speaker 3: You're like, how can I make my time here on

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Speaker 3: Earth less useful?

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Speaker 1: I wasn't so much worried about the positive practical benefits

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Speaker 1: as the negative. You know, my parents worked in the

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Speaker 1: weapons programs, and I really really didn't want to do

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Speaker 1: anything that could be used as the basis of a

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Speaker 1: death ray.

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Speaker 3: I see, But you could have picked something positively useful,

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Speaker 3: like making a chocolate Yeah, there you go, making people happy.

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Speaker 1: Well, you know, my dad did retire from the lab

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Speaker 1: and then became a blacksmith, so he's definitely got useful

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Speaker 1: skills for the end times.

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Speaker 3: He became a blacksmith. Wow, was he forging like swords

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Speaker 3: or internal combustion engines in your garage?

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Speaker 1: Or what swords? Spears? All kinds of stuff?

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Speaker 3: Yes, He's like, I want to wait more weapons.

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Speaker 1: I wish I were joking more and.

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Speaker 3: More direct, but anyways, Welcome to our podcast. Daniel and

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Speaker 3: Jorge Explain the Universe, a production of iHeartRadio.

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Speaker 1: In which our only weapon is our minds. As we

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Speaker 1: tackle the quest of understanding the universe, we go forging

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Speaker 1: through all of the craziness that's out there and try

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Speaker 1: to weave it all together into an explanation that makes sense.

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Speaker 1: We hope that whatever the universe is made out of

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Speaker 1: its time, any little basic bits that somehow they're danced

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Speaker 1: together can explain everything that we experience in the universe,

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Speaker 1: that we can somehow find fundamental laws, and then we

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Speaker 1: can also make sense of it all that's right.

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Speaker 3: We try to hone our knowledge of signs here and

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Speaker 3: try to prepare you for the end times when we'll

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Speaker 3: all be looking up at the stars wondering how do

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Speaker 3: we all get here? And how do we avoid those

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Speaker 3: pesky zombies.

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Speaker 1: I guess we should all try to sharpen our minds

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Speaker 1: so we can slice our way through these problems.

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Speaker 3: Yeah, I'm sure having physics knowledge will be helpful in

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Speaker 3: the apocalypse, right, you can, I guess, try to build

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Speaker 3: a laser gun to fight the zombies.

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Speaker 1: If the zombies assigned a lot of homework problems, then

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Speaker 1: I'm definitely there to help.

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Speaker 3: Oh, that could be another way to defeat them. You know,

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Speaker 3: you give them physics problems that are so tricky that

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Speaker 3: their brains explode, and that everyone knows that's how you

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Speaker 3: kill zombies.

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Speaker 1: Wow. Yes, exactly. Too many into girls.

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Speaker 3: Calculus.

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Speaker 1: No, you know, Newton definitely believed in zombies. Really, Newton

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Speaker 1: definitely believed in some weird stuff. I don't know about zombies,

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Speaker 1: but you know, he was an alchemist and he definitely

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Speaker 1: was a fan of the arcane.

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Speaker 3: Wasn't he really into currencies too?

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Speaker 1: Mm hmmm, yeah, exactly.

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Speaker 3: At some point became like a coin master or something.

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Speaker 1: He was definitely a weird dude.

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Speaker 3: Yes, by word, do you mean a genius who basically

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Speaker 3: invented science.

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Speaker 1: I think that's actually giving him a little bit too

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Speaker 1: much credit. But yeah, he invented lots of physics and

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Speaker 1: big chunks of math, and I think he would be

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Speaker 1: pretty tickled if we could use calculus against the zombies.

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Speaker 3: Oh well, I'm sure a lot of people will be

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Speaker 3: relieved to learn it's useful for something after all that

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Speaker 3: work in high school.

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Speaker 1: Yeah, they can integrate it into their lives.

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Speaker 3: Oh boy, that was very terrifical joke. But anyways, we

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Speaker 3: do like to think about the universe and we try

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Speaker 3: to explain it here on the podcast, and sometimes that

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Speaker 3: involves answering questions.

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Speaker 1: That's right. It's not just Isaac Newton who's thinking about

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Speaker 1: the nature of the universe. It's everybody. The goal of

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Speaker 1: science is to understand the universe, and that means for

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Speaker 1: everybody to figure it out. And that, of course means

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Speaker 1: everybody's got to be out there thinking about the universe,

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Speaker 1: asking questions, wondering how it all works, and we want

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Speaker 1: you to be doing that. We hope that this podcast

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Speaker 1: stimulates your curiosity. You hear on the podcast about the

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Speaker 1: questions we are asking, but we want to hear about

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Speaker 1: the questions you are asking, and then we want to

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Speaker 1: answer them. So if you have questions about the nature

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Speaker 1: of the universe or something you heard about on the podcast,

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Speaker 1: or something you heard about on Gass another podcast, please

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Speaker 1: write to me to questions at Danielanjorge dot com. We'll

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Speaker 1: clear it up for you.

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Speaker 3: Yeah, because it's part of human nature to be asking questions,

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Speaker 3: and it's totally fun to ask questions as well, and

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Speaker 3: so here in the podcast we sometimes like to answer

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Speaker 3: questions that listeners send us, and so to be on

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Speaker 3: the podcast, we'll be tackling listener questions number sixty six.

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Speaker 1: You have a sixty six related snide comment.

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Speaker 3: Only a warning, Daniel. If we keep going, we're going

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Speaker 3: to hit listener questions six sixty six.

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Speaker 1: Oh, I thought you were going to warn me. But

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Speaker 1: listener question sixty nine, where we turn everything upside down.

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Speaker 3: I have warned you repeatedly about that milestone, and you

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Speaker 3: don't seem very concerned.

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Speaker 1: I'm mindlessly barreling towards it.

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Speaker 3: Well, just maybe we'll record it, but then we'll censor it.

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Speaker 1: Maybe we'll just skip it. We'll go straight to seventy.

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Speaker 3: Yeah, seventy isn't new sixty nine.

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Speaker 1: Nobody says that. Don't make that a thing.

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Speaker 3: I don't care if other people say, oh I see,

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Speaker 3: but yeah. We do like to answer questions here on

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Speaker 3: the podcast that listeners said this, and so today we

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Speaker 3: have three awesome questions. They are about galaxies colliding but

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Speaker 3: extreme forces, and about the air we breathe. So let's

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Speaker 3: jump right in. Our first question comes from Pedra from Boston.

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Speaker 4: Hi, Daniel and jre I routinely hear not to worry

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Speaker 4: about the impending collision between our galaxy and the Andromeda galaxy,

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Speaker 4: since the space between the stars within each galaxy is

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Speaker 4: so great there won't be any direct collisions. However, on

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Speaker 4: some of the podcast episodes, it seems as though the

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Speaker 4: orbital stability of the planets in our Solar system isn't

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Speaker 4: all that great. For example, some planets may have traded places,

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Speaker 4: while other planets could have been captured or ejected. So, really,

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Speaker 4: which argument wins? Do I need to tell my descendants

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Speaker 4: to start worrying about it in four point five billion years,

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Speaker 4: I really want them to see the Sun become a

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Speaker 4: red giant.

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Speaker 1: Thanks for the great podcast.

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Speaker 3: All right, interesting question. Basically, should we be worried four

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Speaker 3: and a half billion years from now?

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Speaker 1: Yeah, exactly if we're all alive, or should the zombies

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Speaker 1: that have succeeded us, should they be worried about.

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Speaker 3: What's going to happen? I think that's the best part

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Speaker 3: of being a zombies is you don't have to worry

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Speaker 3: about anything.

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Speaker 1: As long as you've killed off all the people who

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Speaker 1: might assign you homework problems, you're.

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Speaker 3: Fine, man, I wou think the best part of being

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Speaker 3: a zombies you can just turn your brain off.

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Speaker 1: Don't you need to protect it from exploding? Right? Isn't

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Speaker 1: that the kryptonite of zombies?

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Speaker 3: Well, I think fire also kills zombies.

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Speaker 1: Oh boy, wow, Yeah, I'm so glad you've been doing

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Speaker 1: this research.

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Speaker 3: I'm glad the people I'll be hanging out with know

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Speaker 3: how to make a fire.

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Speaker 1: But I think Petra's question is really touching on two

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Speaker 1: things we hear about a lot in science. One that

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Speaker 1: our galaxy is colliding with another galaxy and the other

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Speaker 1: that our solar system is kind of fragile, that the

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Speaker 1: orbits are not really that stable, and so he's worried

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Speaker 1: that even if stars are pretty dilute in the galaxy,

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Speaker 1: would our solar system get upset?

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Speaker 3: Basically, what's going to happen when our galaxy collides with Andromeda?

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Speaker 1: Like?

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Speaker 3: Will be safe?

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Speaker 4: Like?

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Speaker 3: Is nothing going to happen to us? Or should we

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Speaker 3: be concerned that maybe our plant might get disrupted and

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Speaker 3: thrown out into space?

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Speaker 1: Yeah, it's definitely a valid concern, and it touches on

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Speaker 1: a lot of really interesting physics. And the first thing

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Speaker 1: I want to talk about is why Andrama is going

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Speaker 1: to collide with the Milky Way, because I get a

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Speaker 1: lot of questions about exactly this. People hear us talking

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Speaker 1: about how the universe is expanding and space is being

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Speaker 1: created between galaxies, and then they hear us talking about

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Speaker 1: how Andromeda is coming towards us and say, how does

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Speaker 1: that make any sense? Why isn't space expanding between us

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Speaker 1: and Andromeda and pushing it further and further away? And

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Speaker 1: so first we should try to reconcile that apparent contradiction.

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Speaker 4: Mm.

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Speaker 3: Yeah, because we talked about like how because dark energy

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Speaker 3: is expanding the universe, the galaxies out there getting further

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Speaker 3: and further away from us, But we've also talked about

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Speaker 3: how Drama is in a collision course with our galaxy.

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Speaker 1: Yeah, And the answer comes down to distances, and dark

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Speaker 1: energy is something that gets more powerful for distant objects.

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Speaker 1: It's basically like a chunk of space grows a little bit,

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Speaker 1: and so more chunks of space are growing more. So

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Speaker 1: a little tiny chunk of space is hardly growing, but

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Speaker 1: a vast distance between our galaxy cluster and a really

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Speaker 1: distant other galaxy cluster that's kind of growing a lot.

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Speaker 1: And gravity is the opposite. Gravity gets weaker with distance.

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Speaker 1: As things get further apart, gravity fades away. So for

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Speaker 1: stuff that's really close together, like the Earth and the Sun,

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Speaker 1: or even our galaxy in the neighboring galaxy, gravity wins

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Speaker 1: over dark energy. Things that are really really far apart,

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Speaker 1: like clusters of galaxies, not individual galaxies. Dark energy is winning,

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Speaker 1: And most of the universe is far apart from most

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Speaker 1: of the universe, so mostly things are expanding away from

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Speaker 1: each other, but in little neighborhoods like our cluster of galaxy,

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Speaker 1: stuff is still getting pulled together by gravity. So gravity

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Speaker 1: is the reason the Milky Way and Andromeda will collide

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Speaker 1: in a few billion years.

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Speaker 3: Is it gravity or is it just that we just

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Speaker 3: happen to be in a course that intercepts the course

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Speaker 3: of Andromeda, Like is Indrameda really being attracted to our galaxy?

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Speaker 3: I mean, obviously it is, But is it really significant

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Speaker 3: to call it the main reason we're going to collide

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Speaker 3: with it?

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Speaker 1: It definitely is. I mean, the Milky Way Andromeda are

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Speaker 1: part of a cluster of galaxies, and that cluster exists

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Speaker 1: because of gravity, so it's holding it together and the

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Speaker 1: galaxies are sort of sloshing around. It's not guaranteed at

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Speaker 1: any moment that they're going to hit each other, but

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Speaker 1: it's gravity that holds them together, that's pulling them together.

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Speaker 1: It's sort of like asking if a comet falls towards

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Speaker 1: the Sun and it collides to the Sun, why is

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Speaker 1: that Well, it's definitely because of the gravity. That doesn't

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Speaker 1: mean that every comet does collide with the Sun. Gravity

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Speaker 1: is not omnipotent. Sometimes comets go around the back of

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Speaker 1: the Sun in the same way in the local cluster.

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Speaker 1: Not every galaxy is gonna collide with every other galaxy

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Speaker 1: as soon as possible. Sometimes they pass around each other.

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Speaker 1: But it is gravity that's pulling these two together.

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Speaker 3: Well, I guess what I mean is like if you

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Speaker 3: have to asteroids, for example, in the Solar System, and

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Speaker 3: they're gonna collide with each other. I mean, sure, they're

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Speaker 3: in the Solar System together because of the gravity well

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Speaker 3: of the Sun, but the fact that they're colliding with

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Speaker 3: each other as opposed to not colliding, it's mostly just

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Speaker 3: kind of look right, Yeah.

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Speaker 1: It's gravity plus chance. It's possible a cluster where galaxies

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Speaker 1: like ours and Andromeda don't collide until later on. Eventually

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Speaker 1: everything is going to collide and it's all going to

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Speaker 1: collapse into one supermassive black hole. So it's really just

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Speaker 1: a waiting game.

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Speaker 3: But the collision that's going to happen in four and

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Speaker 3: a half billion years, that's basically luck. Right. It's not

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Speaker 3: like it's inevitable. Like if our galaxy was moving a

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Speaker 3: few degrees in another direction, or to the right or

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Speaker 3: to the left, we wouldn't be colliding with Andromeda, would we.

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Speaker 1: Yeah, that's right. If you change the initial conditions, that

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Speaker 1: collision might happen later. It also might happen earlier, Right,

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Speaker 1: it could be that we're lucky we got this far

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Speaker 1: without colliding with Andromeda. So yeah, the whole system is

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Speaker 1: very chaotic, but it is gravity. But gravity is really

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Speaker 1: the only force at play here.

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Speaker 3: And so the reason we're worried about Andromeda and not

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Speaker 3: other galaxies is because the other galaxies are further away,

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Speaker 3: and those are definitely moving away from us because of

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Speaker 3: dark energy, or are some of them potentially getting closer

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Speaker 3: to us.

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Speaker 1: Everything in our galaxy cluster is gravitationally bound, which means

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Speaker 1: it has enough gravity to hold itself together and resist

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Speaker 1: the pull of dark energy, and galaxy clusters are like

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Speaker 1: the biggest thing that have that property. Anything that's larger

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Speaker 1: than that, what we call a supercluster, is probably too

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Speaker 1: big and too spread out for gravity to hold itself together,

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Speaker 1: and dark energy is going to win. So that's sort

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Speaker 1: of the tipping point. So anything that's in our galaxy

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Speaker 1: cluster is eventually going to collapse into one big, super

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Speaker 1: massive black hole. And we're talking very very far in.

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Speaker 3: The future unless dark energy changes, right, Yes, like if

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Speaker 3: it accelerates, then it's going to get a little more crowded,

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Speaker 3: but or if it like weekends, things might get a

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Speaker 3: little room hear.

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Speaker 1: Yeah, I think it's the opposite. If dark energy accelerates,

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Speaker 1: then even our galaxy cluster is going to get torn

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Speaker 1: apart because it becomes more powerful than gravity. We talked

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Speaker 1: about that once on the podcast. There's even a theory

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Speaker 1: of like phantom dark energy, where dark energy gets so

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Speaker 1: powerful that it tears apart atoms and even protons. And

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Speaker 1: if dark energy weakens, then gravity wins over larger distances

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Speaker 1: and it might gather together even superclusters.

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Speaker 3: Right, that's what I meant. I meant the opposite of what.

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Speaker 1: I said, But you're definitely right, and the conceptual part,

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Speaker 1: which is that we don't know what dark energy is

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Speaker 1: or what it's going to do, and we can't really

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Speaker 1: predict it. So this is assuming a naive extrapolation of

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Speaker 1: dark energy, which is basically all we can do at

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Speaker 1: this point.

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Speaker 3: All Right, so we're in a collision course with Andromeda.

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Speaker 3: What's going to happen when we collide?

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Speaker 1: So when we collide with Andromeda, there's a bunch of

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Speaker 1: different components of the galaxy, and you really need to

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Speaker 1: think about each of them individually because they all have

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Speaker 1: different behavior. So, for example, the gas and the dust

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Speaker 1: that are in the two galaxies, those are going to

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Speaker 1: collide and you're going to get all sorts of dramatic stuff.

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Speaker 1: It's going to see the creation of lots of new stars,

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Speaker 1: which would be really exciting. But the stars themselves are

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Speaker 1: very different from the gas and the dust. Right the

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Speaker 1: gas in the dust is very spread out, it's definitely

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Speaker 1: going to smash into the other stuff. But stars are

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Speaker 1: very different from gas and dust. They're not as spread out.

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Speaker 1: They're tiny, and they're clumpy, and they're really really dilute.

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Speaker 1: So when stars approach other stars, it's very hard for

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Speaker 1: them to actually collide because space is really really big,

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Speaker 1: and the stars are really really far apart.

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Speaker 3: I guess how far apart are they? Like how far

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Speaker 3: is there our year's neighbor?

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Speaker 1: So our nearest neighbor is light years away, right, the

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Speaker 1: closest star to us is almost four light years away,

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Speaker 1: and the Sun is the tiny fraction of a light

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Speaker 1: year wide. I mean, if you shrink, for example, the

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Speaker 1: Sun down to the size of a tennis ball that

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Speaker 1: you could hold in your hand, then the nearest neighbor

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Speaker 1: star would be four or five thousand miles away.

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Speaker 3: WHOA, that's like on the other side of the Atlantic kind.

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Speaker 1: Of yeah, exactly. So imagine you're throwing a tennis ball

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Speaker 1: and somebody on the other side of the ocean is

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Speaker 1: throwing a tennis ball. What are the chances that they're

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Speaker 1: going to hit each other over the ocean? Like basically zero?

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Speaker 3: But I guess how wide is the sphere of influence

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Speaker 3: of something like the sun? Like how close do you

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Speaker 3: need to get to it before you feel it's gravity?

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Speaker 1: Yeah? Exactly, good point, because we're not actually just interested

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Speaker 1: in like a collision where like the two stars really

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Speaker 1: touch each other and merge and become one. Stars can

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Speaker 1: pull in each other if they're even near each other. Right,

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Speaker 1: And that's really what Petro's quest is about, is how

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Speaker 1: close does the star need to get to distort our

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Speaker 1: star or distort the orbit of stuff around the star? Right?

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Speaker 1: Because near misses can destabilize things, and we know that

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Speaker 1: already in our galaxy, because other stars are moving relative

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Speaker 1: to the Sun. Sometimes they come closer, sometimes they come

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Speaker 1: further away, and that can distort the orbits of stuff

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Speaker 1: in our Solar system. So it's not a clear, crisp answer.

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Speaker 1: It's not like there's a certain distance within which something

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Speaker 1: happens and out of which nothing happens. It's gradual, Right.

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Speaker 1: The closer it comes, the greater the gravitational distortion.

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Speaker 3: But I guess maybe it depends on how unstable our

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Speaker 3: orbit is or how fragile our orbit is. Do you

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Speaker 3: have a sense of how precarious are a path around

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Speaker 3: the Sun is? Like if I bring in another Sun,

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Speaker 3: I don't know, a few million miles away, is it

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Speaker 3: going to affect us and kick us out of the

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Speaker 3: Solar system or maybe cause us to fall into the Sun,

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Speaker 3: or are we going to be Okay?

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Speaker 1: Yeah, it's a good question. The Earth is pretty stable,

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Speaker 1: like just the Earth in the Solar System is a

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Speaker 1: pretty stable orbit. There's a lot of stuff going on

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Speaker 1: that's going to influence the Earth's orbit that makes its

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Speaker 1: orbit change. For example, like the Sun is losing mass,

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Speaker 1: so it's gravity shrinks. The Sun is also pushing on

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Speaker 1: the Earth, not just pulling on it with gravity, but

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Speaker 1: its wind pushes on the Earth. There's effects of Jupiter,

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Speaker 1: there's gravitational radiation. But you're right, the biggest wild card

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Speaker 1: are like things from outside the Solar System. And this

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Speaker 1: is something we've thought about, not just in the case

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Speaker 1: of another galaxy, but again just stuff in our Solar system. So,

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Speaker 1: for example, there is a star it's called Glease seven

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Speaker 1: to ten that we've been tracking, and we predict that

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Speaker 1: it's gonna come kind of close to our star. It's

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Speaker 1: gonna come within one twenty fifth of the distance to

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Speaker 1: Proxima Centauri. So Proximus Centauri is four light years away,

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Speaker 1: and so this is gonna come like an eighth of

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Speaker 1: a light year away from our star.

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Speaker 3: Oh wait, wait, wait, so this is a star that's

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Speaker 3: gonna come within one twenty fifth of the nearest star. Yeah,

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Speaker 3: would it become the nearest star if it's coming close

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Speaker 3: to us.

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Speaker 1: Yeah, that's just for scale, our current nearest stars for

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Speaker 1: light years away. This one's going to come within one

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Speaker 1: twenty fifth of that distance again in the far far future.

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Speaker 1: How far in the future, in about one and a

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Speaker 1: half million years.

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Speaker 3: Oh, that's pretty soon cosmically speaking.

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Speaker 1: Yeah, it's a lot of generations to survive between now

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Speaker 1: and then. But yeah, that's not far away, and it's

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Speaker 1: definitely a lot sooner than when the Milky Way collides

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Speaker 1: with Andromeda.

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Speaker 3: And this is a star that's like traveling through space

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Speaker 3: relative to us, or are we traveling close to it?

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Speaker 3: You know what I mean? Like, is this an anomaly

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Speaker 3: or in our quiet neighborhood or is it all part

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Speaker 3: of the movement of the stars.

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Speaker 1: It's part of all the movement of the stars around

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Speaker 1: the center of the galaxy. You know, all the stars

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Speaker 1: are orbiting the center and they orbit at different velocities. Also,

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Speaker 1: the stars are moving up and down. They're sort of

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Speaker 1: like wiggling through the plane of the galaxy. And so

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Speaker 1: the stars that are in our immediate neighborhood change over

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Speaker 1: millions of years as these stars sort of swim through

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Speaker 1: the lazy river differently. So this is a totally normal

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Speaker 1: thing to happen.

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Speaker 3: And what does scientists predict this is going to happen

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Speaker 3: when the start flies close to us? Is it gonna

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Speaker 3: disrupt us? Or are we going to feel it?

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Speaker 1: So we are probably not going to feel it directly,

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Speaker 1: in the sense that it's not going to come close

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Speaker 1: enough to perturb the Earth's orbit. So that's already kind

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Speaker 1: of an answer, like you can come fairly close to

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Speaker 1: the Solar System, you know, within an ace of a

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Speaker 1: light year, and really have no effect on the Earth's

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Speaker 1: orbit directly, but it could have serious impacts for life

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Speaker 1: on Earth because it could impact stuff that's in the

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Speaker 1: outer Solar System that could then rain down on the

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Speaker 1: inner Solar System. The very far edges of the Solar System,

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Speaker 1: past Pluto and all the dwarf planets is a theoretical

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Speaker 1: cloud of trillions of icy objects called the Ort cloud.

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Speaker 1: We think it's probably the source of long period comets.

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Speaker 1: These things are really really far away compared to stuff

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Speaker 1: in the inner Solar System or even to Pluto, and

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Speaker 1: so a near passing star could disturb some of these.

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Speaker 1: There's lots of them, and they take just like a

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Speaker 1: little nudge to fall out of their orbit and come

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Speaker 1: barreling into the inner Solar System, where they could become

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Speaker 1: very high speed, very dangerous comets that could impact on

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Speaker 1: the Earth.

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Speaker 3: Whoa, but it maybe it might be get lucky not

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Speaker 3: get hit by right, because even the space between us

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Speaker 3: and the Sun is huge.

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Speaker 1: Yeah, absolutely, we might get lucky and we could get

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Speaker 1: protected by Jupiter.

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Speaker 5: Right.

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Speaker 1: Jupiter has a lot of gravity and it tends to

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Speaker 1: shield the Inner Solar System by pulling these things towards it.

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Speaker 1: Like when comet Shoemaker Levey came through the Solar System

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Speaker 1: in the nineties, it impacted on Jupiter and that wasn't

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Speaker 1: an accident. Not only is Jupiter just a much bigger target,

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Speaker 1: but it has that gravity. But it's not a die

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Speaker 1: you want to roll. It's sort of like playing cosmic

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Speaker 1: Russian Roulette.

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Speaker 5: You know.

440
00:20:44,359 --> 00:20:46,760
Speaker 1: If a star comes by and dislodges a lot of

441
00:20:46,880 --> 00:20:50,960
Speaker 1: art cloud objects tens millions even for example, then we're

442
00:20:50,960 --> 00:20:52,560
Speaker 1: gonna have to get lucky a lot of times to

443
00:20:52,640 --> 00:20:55,919
Speaker 1: avoid being hit. So that's the most likely scenario for

444
00:20:56,000 --> 00:20:58,800
Speaker 1: Glease and also for the collision between Andromeda and the

445
00:20:58,800 --> 00:21:01,280
Speaker 1: Milky Way, that our cloud gets perturbed.

446
00:21:01,760 --> 00:21:04,960
Speaker 3: Well, well, but I guess what is the scenario that's

447
00:21:05,280 --> 00:21:07,439
Speaker 3: going to happen when we collibe with Andromeda. Are we

448
00:21:07,440 --> 00:21:10,080
Speaker 3: going to see a lot of these stars flying as

449
00:21:10,080 --> 00:21:11,920
Speaker 3: close as Gleek or is it going to be worse

450
00:21:12,119 --> 00:21:14,240
Speaker 3: because I imagine, you know, the nearest star to us

451
00:21:14,400 --> 00:21:16,600
Speaker 3: is pretty far away, but you know, we're colliding with

452
00:21:16,640 --> 00:21:20,720
Speaker 3: a cloud of one hundred billion stars. Maybe that increases

453
00:21:20,720 --> 00:21:22,440
Speaker 3: the chances of something flying closer.

454
00:21:22,600 --> 00:21:25,040
Speaker 1: Yeah. Actually, Andromeda is much bigger than the Milky Way.

455
00:21:25,080 --> 00:21:28,560
Speaker 1: There's lots more stars in Andromeda than in the Milky Way.

456
00:21:28,760 --> 00:21:31,080
Speaker 1: It's really a big, fat galaxy. I mean in a

457
00:21:31,160 --> 00:21:34,160
Speaker 1: very positive way. And so there's no specific answers. There's

458
00:21:34,200 --> 00:21:37,560
Speaker 1: just chances. Right. The chances of a direct collision are zero,

459
00:21:37,960 --> 00:21:40,960
Speaker 1: the chances of a near miss are larger. The chances

460
00:21:41,000 --> 00:21:43,280
Speaker 1: of stars flying sort of within a light year or

461
00:21:43,280 --> 00:21:46,400
Speaker 1: so is reasonable. I haven't done the actual calculations, don't

462
00:21:46,400 --> 00:21:49,919
Speaker 1: have numbers, but qualitatively it's extraordinarily unlikely for a direct

463
00:21:49,920 --> 00:21:52,960
Speaker 1: star star collision. I think it's quite likely for a

464
00:21:53,000 --> 00:21:55,920
Speaker 1: near miss like Glease seven to ten. But I think

465
00:21:55,960 --> 00:21:58,840
Speaker 1: the most likely scenario is that no star comes really

466
00:21:58,880 --> 00:22:01,120
Speaker 1: anywhere near us, though there are a lot of them.

467
00:22:01,320 --> 00:22:03,320
Speaker 1: There are also very very spread out.

468
00:22:03,960 --> 00:22:05,560
Speaker 3: No, should we just think your word for it, or

469
00:22:06,320 --> 00:22:08,959
Speaker 3: should maybe one of you guys get on the computer

470
00:22:09,040 --> 00:22:10,760
Speaker 3: and simulate this to figure it out.

471
00:22:11,359 --> 00:22:13,200
Speaker 1: We've got four and a half billion years to figure

472
00:22:13,200 --> 00:22:15,160
Speaker 1: it out, so yeah, that's enough computation time.

473
00:22:16,160 --> 00:22:19,399
Speaker 3: I don't know. I like to plan ahead, as you know. No,

474
00:22:19,640 --> 00:22:20,560
Speaker 3: you gotta get ready.

475
00:22:20,680 --> 00:22:23,280
Speaker 1: The problem with these calculations is that the further in

476
00:22:23,320 --> 00:22:26,639
Speaker 1: the future you have to extrapolate, the more uncertainty there is.

477
00:22:27,240 --> 00:22:29,919
Speaker 1: Right Like, NASA can predict the path of these objects

478
00:22:29,960 --> 00:22:32,760
Speaker 1: for one hundred years very precisely. You ask them to

479
00:22:32,760 --> 00:22:34,840
Speaker 1: tell you where they're going to be in five billion years,

480
00:22:34,840 --> 00:22:38,800
Speaker 1: they have no idea because small uncertainties add up over

481
00:22:38,840 --> 00:22:42,560
Speaker 1: time to make those predictions essentially useless. So our understanding,

482
00:22:42,560 --> 00:22:44,439
Speaker 1: for example, of the dark matter in the Milky Way

483
00:22:44,480 --> 00:22:46,440
Speaker 1: will affect this and the dark matter and androma and the

484
00:22:46,520 --> 00:22:48,840
Speaker 1: dark matter between us and them. So we could do

485
00:22:48,880 --> 00:22:51,120
Speaker 1: a calculation and give you a number, but it's gonna

486
00:22:51,119 --> 00:22:52,680
Speaker 1: be different next year, and it's gonna be different in

487
00:22:52,720 --> 00:22:55,240
Speaker 1: a million years, it's gonna be different in a billion years.

488
00:22:55,480 --> 00:22:57,800
Speaker 3: Well, I mean, you don't need to predict what's going

489
00:22:57,880 --> 00:22:59,720
Speaker 3: to happen exactly, But could you maybe get us that

490
00:22:59,800 --> 00:23:02,159
Speaker 3: this sense? Like if I take a cloud of stars

491
00:23:02,240 --> 00:23:05,679
Speaker 3: like the Andromeda galaxy, and you take a cloud of

492
00:23:05,680 --> 00:23:08,080
Speaker 3: stars like the Milky Way galaxy, and you smash them

493
00:23:08,080 --> 00:23:10,320
Speaker 3: into each other at the speed are going, what are

494
00:23:10,359 --> 00:23:12,840
Speaker 3: the chances or how likely or you know, how often

495
00:23:12,880 --> 00:23:16,160
Speaker 3: would a star come near as enough to disrupt our orbit?

496
00:23:16,880 --> 00:23:19,720
Speaker 1: That's totally possible, and probably somebody is working on that,

497
00:23:19,840 --> 00:23:21,640
Speaker 1: but I haven't actually seen that number anywhere.

498
00:23:23,040 --> 00:23:26,520
Speaker 3: All right, Well, then the answer for Petra is hopefully

499
00:23:26,640 --> 00:23:29,440
Speaker 3: not nothing bad will happen. Daniel doesn't think.

500
00:23:29,560 --> 00:23:31,560
Speaker 1: Don't worry too much about it, Petra. Zombies are much

501
00:23:31,600 --> 00:23:32,080
Speaker 1: more likely.

502
00:23:32,800 --> 00:23:36,399
Speaker 3: Yeah, don't collide with any zombies if you can't, especially

503
00:23:36,440 --> 00:23:37,119
Speaker 3: when with teeth.

504
00:23:37,520 --> 00:23:39,640
Speaker 1: But keep working on those intervals. That's going to save

505
00:23:39,680 --> 00:23:40,560
Speaker 1: you in the end times.

506
00:23:40,840 --> 00:23:43,120
Speaker 3: That's right. Bring your math book whenever you go out

507
00:23:43,200 --> 00:23:47,840
Speaker 3: foraging for you know, particle colliders to start in your fire.

508
00:23:48,960 --> 00:23:50,919
Speaker 1: Or do what my dad did. Become a blacksmith and

509
00:23:51,000 --> 00:23:52,120
Speaker 1: make your own weapons.

510
00:23:52,400 --> 00:23:56,760
Speaker 3: Oh yeah, that's a good suggestion. Or just go to

511
00:23:56,960 --> 00:23:59,520
Speaker 3: Daniel's garage and you know, steal some of those swords.

512
00:24:00,560 --> 00:24:03,600
Speaker 1: I wouldn't recommend that that's pretty well protected.

513
00:24:04,840 --> 00:24:09,159
Speaker 3: By math. If you come within ten meters, you'll be

514
00:24:09,200 --> 00:24:12,800
Speaker 3: faced with some physics questions, or you could just blast

515
00:24:12,840 --> 00:24:16,359
Speaker 3: the podcast out in speakers. They'll keep everyone away. All right,

516
00:24:16,400 --> 00:24:18,199
Speaker 3: let's get to our other questions here today, and we

517
00:24:18,280 --> 00:24:22,359
Speaker 3: have some questions about extreme forces in the universe and

518
00:24:22,600 --> 00:24:25,720
Speaker 3: about what kind of air are we all breathing? So

519
00:24:25,760 --> 00:24:28,439
Speaker 3: we'll dig into those, but first let's take a quick break.

520
00:24:41,359 --> 00:24:41,479
Speaker 4: Right.

521
00:24:41,480 --> 00:24:45,600
Speaker 3: We're answering listener questions, and our second question comes from Derek,

522
00:24:46,040 --> 00:24:48,800
Speaker 3: who comes from the planet Earth.

523
00:24:49,119 --> 00:24:52,399
Speaker 1: I guess probably we hope, so, no, we hope not.

524
00:24:53,800 --> 00:24:56,920
Speaker 3: Yeah, Hi Daniel and Jorge.

525
00:24:57,240 --> 00:25:00,600
Speaker 5: So I have a question about extreme forces. Gravity is

526
00:25:00,600 --> 00:25:03,600
Speaker 5: one of the weakest forces in nature, but it seems

527
00:25:03,600 --> 00:25:05,800
Speaker 5: like there's no limit to how much gravity there can be,

528
00:25:06,160 --> 00:25:08,360
Speaker 5: and once you have enough of it, an event horizon

529
00:25:08,440 --> 00:25:11,160
Speaker 5: is formed and a black hole is made. Even then,

530
00:25:11,480 --> 00:25:14,320
Speaker 5: more masks can be added and gravity will continue to increase.

531
00:25:15,080 --> 00:25:17,160
Speaker 5: Can this be done with any of the other forces,

532
00:25:17,520 --> 00:25:20,359
Speaker 5: Like can a magnetic field become so strong that it

533
00:25:20,400 --> 00:25:23,080
Speaker 5: forms its own kind of event horizon? Or is there

534
00:25:23,080 --> 00:25:25,960
Speaker 5: a limit that prevents the other forces from increasing infinitely?

535
00:25:26,600 --> 00:25:29,680
Speaker 3: Thank you all, right, interesting question, I guess The question

536
00:25:29,760 --> 00:25:33,520
Speaker 3: is how extreme can other forces get? Can you make

537
00:25:33,600 --> 00:25:36,960
Speaker 3: like a magnetic black hole or a weak black hole?

538
00:25:37,680 --> 00:25:37,880
Speaker 2: Yeah?

539
00:25:38,119 --> 00:25:41,680
Speaker 1: Super fun question, really great to think about, and I

540
00:25:41,720 --> 00:25:45,200
Speaker 1: love the sort of philosophy behind this question. Trying to

541
00:25:45,240 --> 00:25:48,399
Speaker 1: make connections between forces and try to understand the differences

542
00:25:48,440 --> 00:25:52,199
Speaker 1: between ideas. This is really how you make progress in physics.

543
00:25:52,240 --> 00:25:54,720
Speaker 1: How you build a consistent model in your head, try

544
00:25:54,720 --> 00:25:56,760
Speaker 1: to understand where that model doesn't work and where the

545
00:25:56,760 --> 00:25:59,400
Speaker 1: bits don't fit together, and then try to understand how

546
00:25:59,400 --> 00:26:02,200
Speaker 1: they can possi click together. So kudos to you, Derek

547
00:26:02,240 --> 00:26:03,840
Speaker 1: for thinking about it this way and for asking this

548
00:26:03,920 --> 00:26:04,520
Speaker 1: great question.

549
00:26:06,119 --> 00:26:09,359
Speaker 3: All right, The question is Derek is wondering, like, we

550
00:26:09,400 --> 00:26:12,200
Speaker 3: know that a black hole happens when you gravity gets

551
00:26:12,240 --> 00:26:15,760
Speaker 3: so intense that it becomes basically a black hole with

552
00:26:15,800 --> 00:26:19,240
Speaker 3: an event horizon. Can that sort of thing happen with

553
00:26:19,359 --> 00:26:22,840
Speaker 3: the other forces in nature, like electromagnetism or the weak

554
00:26:22,880 --> 00:26:25,480
Speaker 3: force or the strong force. Can you get a situation

555
00:26:25,520 --> 00:26:28,080
Speaker 3: where the magnetic force is so strong it can maybe

556
00:26:28,119 --> 00:26:30,080
Speaker 3: creates its own kind of event horizon.

557
00:26:30,840 --> 00:26:34,440
Speaker 1: Yeah, so super fun question, and it's tempting to think

558
00:26:34,480 --> 00:26:37,280
Speaker 1: that there is because Derek probably thinks about gravity as

559
00:26:37,280 --> 00:26:39,879
Speaker 1: a force in the same way he thinks about magnetism

560
00:26:39,920 --> 00:26:44,400
Speaker 1: as a force, and that it creates an acceleration on objects. Right,

561
00:26:44,480 --> 00:26:47,640
Speaker 1: Two objects, as Newton described that have masks will pull

562
00:26:47,640 --> 00:26:50,560
Speaker 1: on each other the same way two objects with electric charge,

563
00:26:50,720 --> 00:26:53,480
Speaker 1: the electric force will pull on them or push on them,

564
00:26:53,840 --> 00:26:56,119
Speaker 1: and the strong force pulls and pushes on things that

565
00:26:56,240 --> 00:26:59,080
Speaker 1: have color charge. And so it's tempting to think about that,

566
00:26:59,080 --> 00:27:02,399
Speaker 1: and it's very intuitive, but remember that gravity is not

567
00:27:02,480 --> 00:27:05,959
Speaker 1: actually a force. It's our understanding of gravity today is

568
00:27:06,000 --> 00:27:09,479
Speaker 1: that it represents the curvature of space time itself, and

569
00:27:09,520 --> 00:27:12,240
Speaker 1: in many ways that's equivalent. Like most of the time,

570
00:27:12,280 --> 00:27:14,320
Speaker 1: you can think about the curvature of space time and

571
00:27:14,680 --> 00:27:16,919
Speaker 1: from that you can get exactly the same behavior that

572
00:27:17,040 --> 00:27:20,680
Speaker 1: Newton would have predicted, but it's also crucially different in

573
00:27:20,720 --> 00:27:23,520
Speaker 1: many respects. There's lots of things that the curvature of

574
00:27:23,560 --> 00:27:26,760
Speaker 1: space time can do that the simple force of gravity

575
00:27:26,800 --> 00:27:30,480
Speaker 1: cannot do. And form an event horizon is one of

576
00:27:30,520 --> 00:27:34,600
Speaker 1: those things. So Einstein's reconception of gravity as a curvature

577
00:27:34,640 --> 00:27:38,000
Speaker 1: of space time describes all of Newton's physics, but also

578
00:27:38,200 --> 00:27:42,160
Speaker 1: more than that, it doesn't just reformulate gravity. As another

579
00:27:42,160 --> 00:27:45,560
Speaker 1: way to think about it, it adds new capacity to gravity,

580
00:27:45,800 --> 00:27:48,320
Speaker 1: new things that it can do. And so the force

581
00:27:48,400 --> 00:27:51,719
Speaker 1: description of gravity cannot create an event horizon, but the

582
00:27:51,760 --> 00:27:55,879
Speaker 1: curvature description of gravity can create event horizons. And so

583
00:27:55,960 --> 00:27:58,720
Speaker 1: the other forces which can't be described in terms of

584
00:27:58,720 --> 00:28:02,399
Speaker 1: curvature can't create event horizons. That's not something a force

585
00:28:02,480 --> 00:28:05,080
Speaker 1: can do. Only spacetime curvature can do that.

586
00:28:05,800 --> 00:28:08,600
Speaker 3: Well, I guess I might ask, are you sure about that?

587
00:28:09,800 --> 00:28:13,040
Speaker 3: Couldn't you define the event horizon as the point at

588
00:28:13,080 --> 00:28:15,520
Speaker 3: which the force of gravity is so strong that nothing

589
00:28:15,560 --> 00:28:16,199
Speaker 3: can escape it.

590
00:28:16,680 --> 00:28:19,680
Speaker 1: I'm definitely not sure about that, because we don't understand

591
00:28:19,680 --> 00:28:23,680
Speaker 1: gravity right. Gravity is really weird. Einstein's theory is beautiful,

592
00:28:23,720 --> 00:28:26,679
Speaker 1: but we also know that it's flawed. We don't understand

593
00:28:26,800 --> 00:28:30,280
Speaker 1: how singularities could form. We don't understand why gravity seems

594
00:28:30,320 --> 00:28:32,520
Speaker 1: to not be quantum mechanical, or if it is when

595
00:28:32,560 --> 00:28:36,000
Speaker 1: you zoom in enough, for example. So everything we say

596
00:28:36,040 --> 00:28:39,280
Speaker 1: here today assumes that GR is correct, but we know

597
00:28:39,400 --> 00:28:43,480
Speaker 1: that GR is not correct ultimately, and so there's lots

598
00:28:43,520 --> 00:28:45,400
Speaker 1: of things to be learned, and in the far future

599
00:28:45,600 --> 00:28:48,080
Speaker 1: this could all be totally wrong. So yeah, absolutely not,

600
00:28:48,520 --> 00:28:50,360
Speaker 1: But you're right. First, we should define what we mean

601
00:28:50,440 --> 00:28:53,480
Speaker 1: by an event horizon, right, And the reason a black

602
00:28:53,480 --> 00:28:55,480
Speaker 1: hole can exist, the reason we have event horizons, the

603
00:28:55,520 --> 00:28:58,880
Speaker 1: reason that curvature can do this and the forces cannot,

604
00:28:59,320 --> 00:29:02,480
Speaker 1: is that curvature does something to space. It changes the

605
00:29:02,480 --> 00:29:06,040
Speaker 1: shape of space, like the relationship between points. So you

606
00:29:06,040 --> 00:29:07,760
Speaker 1: can think about it as like a region from which

607
00:29:07,840 --> 00:29:11,360
Speaker 1: even a photon cannot escape, right, And that again is

608
00:29:11,400 --> 00:29:13,960
Speaker 1: something gravity can do. But you can't do that with

609
00:29:14,120 --> 00:29:16,560
Speaker 1: magnetism or electric force or the strong force.

610
00:29:17,040 --> 00:29:19,040
Speaker 3: Well, I guess what I mean is, like, you know,

611
00:29:19,680 --> 00:29:22,000
Speaker 3: for example, you might say that the Earth has an

612
00:29:22,000 --> 00:29:25,480
Speaker 3: event horizon, right, Like there's a point and a velocity

613
00:29:25,560 --> 00:29:28,600
Speaker 3: at which you can escape to Earth, and there's a

614
00:29:28,640 --> 00:29:31,800
Speaker 3: point at which you cannot escape Earth. Right, So maybe

615
00:29:31,840 --> 00:29:33,720
Speaker 3: you might be able to call that the event horizon

616
00:29:33,760 --> 00:29:37,280
Speaker 3: of the Earth gravity black holes event horizon. It's just that.

617
00:29:37,400 --> 00:29:40,080
Speaker 3: But taking to the extreme where you're talking about not

618
00:29:40,120 --> 00:29:42,360
Speaker 3: even light being able to escape, I wonder if you

619
00:29:42,360 --> 00:29:44,800
Speaker 3: can do that the same with a magnetic field or

620
00:29:44,960 --> 00:29:47,560
Speaker 3: electromagnetic force, Like is there a point at which not

621
00:29:47,640 --> 00:29:50,760
Speaker 3: even like a super fast moving charged particle will escape

622
00:29:50,920 --> 00:29:54,240
Speaker 3: the attractive force that something has electromagnetically.

623
00:29:54,520 --> 00:29:57,080
Speaker 1: I mean, you can definitely form bound states, right, Like

624
00:29:57,600 --> 00:30:00,880
Speaker 1: the Moon is bound to the Earth gravitation, but it

625
00:30:00,920 --> 00:30:04,480
Speaker 1: can still escape, right, Or photons from the Moon can

626
00:30:04,480 --> 00:30:08,440
Speaker 1: definitely escape the gravitational system. And that's not just like

627
00:30:08,520 --> 00:30:12,080
Speaker 1: a difference in degree, it's a difference in kind. Right.

628
00:30:12,120 --> 00:30:14,560
Speaker 1: The inside of an event horizon really is cut off

629
00:30:14,680 --> 00:30:17,800
Speaker 1: from the rest of the universe. Nothing that happens there

630
00:30:17,840 --> 00:30:21,000
Speaker 1: can influence anything that happens outside the universe, whereas things

631
00:30:21,000 --> 00:30:23,840
Speaker 1: that happen on Earth can always influence things far away.

632
00:30:23,880 --> 00:30:26,560
Speaker 1: It just takes some time. So it's a question of

633
00:30:26,600 --> 00:30:29,360
Speaker 1: like causality, like are these things linked or not? Can

634
00:30:29,680 --> 00:30:32,920
Speaker 1: one area of space affect another? You can definitely attract

635
00:30:32,920 --> 00:30:34,880
Speaker 1: things together, and they can even be stuck together, and

636
00:30:34,920 --> 00:30:36,520
Speaker 1: they can be stable, and they can even last for

637
00:30:36,640 --> 00:30:39,800
Speaker 1: millions or billions of years or configurations, Like the proton

638
00:30:39,920 --> 00:30:43,240
Speaker 1: might last forever, but you know, the quarks inside the

639
00:30:43,240 --> 00:30:46,200
Speaker 1: proton could still potentially escape you give them enough energy.

640
00:30:47,120 --> 00:30:49,000
Speaker 1: It's a bound stay. That's not the same thing as

641
00:30:49,040 --> 00:30:49,880
Speaker 1: an event horizon.

642
00:30:50,080 --> 00:30:52,640
Speaker 3: But could you say that, like a charge ball of

643
00:30:52,760 --> 00:30:56,000
Speaker 3: electricity has an escape velocity to it and a point

644
00:30:56,000 --> 00:30:58,160
Speaker 3: at which no charge particle can escape it.

645
00:30:58,360 --> 00:31:01,160
Speaker 1: A charge ball, for example, definitely has an escape velocity,

646
00:31:01,200 --> 00:31:03,760
Speaker 1: like there's a minimum energy you would need to escape

647
00:31:03,960 --> 00:31:07,040
Speaker 1: the potential well created by that ball, and things below

648
00:31:07,040 --> 00:31:08,600
Speaker 1: that energy are bound to it, but there is still

649
00:31:08,640 --> 00:31:11,280
Speaker 1: always an escape velocity. And that's why photons are a

650
00:31:11,400 --> 00:31:14,720
Speaker 1: useful way to think about event horizons, because there's no

651
00:31:14,880 --> 00:31:17,680
Speaker 1: force that can bound a photon. Like photons always move

652
00:31:18,000 --> 00:31:20,640
Speaker 1: at the speed of light locally, and there's no force

653
00:31:20,680 --> 00:31:23,200
Speaker 1: that can prevent them from doing that. But changing the

654
00:31:23,240 --> 00:31:26,320
Speaker 1: direction of space, right, changing the configuration of space the

655
00:31:26,320 --> 00:31:29,520
Speaker 1: way gravity does, that can trap a photon because it

656
00:31:29,560 --> 00:31:31,560
Speaker 1: can change space from flat to curve. You can make

657
00:31:31,560 --> 00:31:34,640
Speaker 1: the photon move in a circle forever, which is sort

658
00:31:34,680 --> 00:31:37,400
Speaker 1: of amazing. And so that's why gravity can do this,

659
00:31:37,640 --> 00:31:39,160
Speaker 1: which no other force can do.

660
00:31:39,880 --> 00:31:45,200
Speaker 3: But I guess light is an electrically neutral right, Yeah,

661
00:31:45,320 --> 00:31:47,160
Speaker 3: So I wonder if you can envision, like, is there

662
00:31:47,520 --> 00:31:50,400
Speaker 3: a ball of charge that can be so intense that

663
00:31:50,560 --> 00:31:52,520
Speaker 3: not even a core going at the speed of light

664
00:31:52,560 --> 00:31:55,040
Speaker 3: can escape it? Do you maybe call that the event

665
00:31:55,080 --> 00:31:57,600
Speaker 3: horizon of an electromagnetic force.

666
00:31:57,880 --> 00:31:59,719
Speaker 1: So you take a ball of charge has a very

667
00:31:59,720 --> 00:32:03,560
Speaker 1: strong electric force, right, and now imagine some electron near it,

668
00:32:03,600 --> 00:32:06,200
Speaker 1: and you're wondering, like, is it possible to have that

669
00:32:06,280 --> 00:32:09,240
Speaker 1: ball be so electrically charged that even an electron moving

670
00:32:09,280 --> 00:32:12,200
Speaker 1: at the speed of light couldn't escape it. Yeah, yeah,

671
00:32:12,240 --> 00:32:14,480
Speaker 1: it's a great question. The problem is that electrons can't

672
00:32:14,520 --> 00:32:16,880
Speaker 1: move at the speed of light because they have mass.

673
00:32:17,240 --> 00:32:20,560
Speaker 3: Right, Well, of course I know this, but like, if

674
00:32:20,600 --> 00:32:22,520
Speaker 3: it was moving at the speed of light, is there

675
00:32:22,560 --> 00:32:25,520
Speaker 3: a point we're closing on nin point nine nine nine percent? Yeah,

676
00:32:25,560 --> 00:32:27,640
Speaker 3: the speed of light. Is there an event horizon for

677
00:32:27,680 --> 00:32:29,080
Speaker 3: that ball of positive charge?

678
00:32:29,160 --> 00:32:31,560
Speaker 1: Right? And I bring up the velocity not just to

679
00:32:31,600 --> 00:32:34,320
Speaker 1: be like actually, but because velocity is the wrong way

680
00:32:34,360 --> 00:32:36,880
Speaker 1: to think about it, because for a massive object, energy

681
00:32:36,960 --> 00:32:38,760
Speaker 1: is the right way to think about it. As you say,

682
00:32:38,760 --> 00:32:40,400
Speaker 1: it can't get to the speed of light. You can

683
00:32:40,400 --> 00:32:42,920
Speaker 1: get arbitrarily close, but there's no limit to the amount

684
00:32:42,920 --> 00:32:45,960
Speaker 1: of energy that an electron can have, and so you

685
00:32:46,000 --> 00:32:48,680
Speaker 1: can just keep putting energy into that electron and eventually

686
00:32:48,720 --> 00:32:52,200
Speaker 1: it will escape that ball of charge. So no, there's

687
00:32:52,240 --> 00:32:54,800
Speaker 1: no way you can trap an electron forever. You can't

688
00:32:54,840 --> 00:32:57,960
Speaker 1: create an event horizon using electric charge. You could always

689
00:32:58,000 --> 00:33:00,320
Speaker 1: just give that electron more energy and it would escape

690
00:33:00,320 --> 00:33:02,320
Speaker 1: your ball of charge no matter how big it is.

691
00:33:03,760 --> 00:33:06,480
Speaker 3: All right, So then the answer for Derek is no,

692
00:33:06,640 --> 00:33:08,400
Speaker 3: you can't make an electromagnetic black hole.

693
00:33:08,640 --> 00:33:10,880
Speaker 1: Yeah, and I think there's another wrinkle there, which is

694
00:33:10,880 --> 00:33:14,720
Speaker 1: something you brought up, which is photons are neutral electromagnetically, right,

695
00:33:15,200 --> 00:33:17,360
Speaker 1: And I think that's really cool. I'm kind of weird

696
00:33:17,560 --> 00:33:21,040
Speaker 1: that photons, even though they carry electromagnetic information, they don't

697
00:33:21,080 --> 00:33:24,120
Speaker 1: feel the force themselves. And that's something true about all

698
00:33:24,120 --> 00:33:27,760
Speaker 1: of the forces, electromagnetism, the weak force, a strong force,

699
00:33:27,880 --> 00:33:30,880
Speaker 1: there are always some particles that are neutral to it, right, So,

700
00:33:31,000 --> 00:33:34,400
Speaker 1: like the strong force can create really really strong bound states,

701
00:33:34,640 --> 00:33:36,840
Speaker 1: but then neutrinos ignore it, right, they would just fly

702
00:33:36,960 --> 00:33:39,200
Speaker 1: right through it. So in that sense, an event horizon

703
00:33:39,280 --> 00:33:42,440
Speaker 1: for like electromagnetism wouldn't really be an event horizon even

704
00:33:42,480 --> 00:33:44,959
Speaker 1: if you could make one, because some particles ignore it.

705
00:33:45,280 --> 00:33:48,360
Speaker 1: The amazing, awesome thing about gravity is that nothing can

706
00:33:48,400 --> 00:33:51,600
Speaker 1: ignore it. Gravity is just linked to energy. So anything

707
00:33:51,640 --> 00:33:54,240
Speaker 1: that has energy, which is basically anything in the way

708
00:33:54,280 --> 00:33:57,800
Speaker 1: we conceive of it, is affected by gravity. It's inescapable.

709
00:33:58,400 --> 00:34:02,120
Speaker 3: Oh all right, hmm I'm still wondering, like, could you

710
00:34:02,200 --> 00:34:04,480
Speaker 3: make that calculation? Like, what did you take an electron,

711
00:34:05,120 --> 00:34:07,680
Speaker 3: give it the speed of light? Could you use that

712
00:34:07,840 --> 00:34:11,960
Speaker 3: to compute a positive ball of charge strong enough for

713
00:34:12,040 --> 00:34:13,800
Speaker 3: which that's the escape velocity.

714
00:34:14,440 --> 00:34:16,640
Speaker 1: Well, if you have an electron and you effectively give

715
00:34:16,680 --> 00:34:19,560
Speaker 1: it velocity the speed of light, you're giving it infinite energy.

716
00:34:20,280 --> 00:34:23,200
Speaker 1: And of course that's impossible. But what that means is

717
00:34:23,520 --> 00:34:27,040
Speaker 1: that there is no ball of charge that's powerful enough

718
00:34:27,120 --> 00:34:29,719
Speaker 1: to bound it because there's infinite energy, so has more

719
00:34:29,800 --> 00:34:33,040
Speaker 1: energy than any energy level in that bound state unless

720
00:34:33,080 --> 00:34:35,400
Speaker 1: you make that ball infinite. Right, So now it's like

721
00:34:35,560 --> 00:34:37,080
Speaker 1: infinity versus infinity.

722
00:34:37,400 --> 00:34:38,719
Speaker 3: Well, I guess what I mean is like, when you

723
00:34:38,719 --> 00:34:42,200
Speaker 3: compute the escape velocity of something escaping Earth, you're not

724
00:34:42,239 --> 00:34:45,920
Speaker 3: actually using the relativistic equations, right, You're just kind of

725
00:34:46,000 --> 00:34:49,160
Speaker 3: using more basic math. You're ignoring relativist effects.

726
00:34:49,200 --> 00:34:52,360
Speaker 1: Right, Yeah, the simplest calculations ignore relativistic effects. But I

727
00:34:52,360 --> 00:34:55,760
Speaker 1: don't think relativistic effects are really relevant for the Earth.

728
00:34:56,160 --> 00:34:58,960
Speaker 3: Right, But so let's say I do that for an electron,

729
00:35:00,120 --> 00:35:03,520
Speaker 3: give it the speed of light. Could I compute an

730
00:35:03,520 --> 00:35:06,800
Speaker 3: event horizon, even though maybe it's not realistic, but it

731
00:35:07,000 --> 00:35:08,040
Speaker 3: is there. One.

732
00:35:08,320 --> 00:35:10,680
Speaker 1: So you're saying, if I ignore the fact that electrons

733
00:35:10,719 --> 00:35:14,200
Speaker 1: can't go the speed of light and I ignore relativity,

734
00:35:14,520 --> 00:35:16,480
Speaker 1: can we make an event horizon for an electron.

735
00:35:16,600 --> 00:35:18,920
Speaker 3: Yeah, just like when we compute the escape velocity of

736
00:35:18,960 --> 00:35:21,920
Speaker 3: a satellite or a spacecraft, we sort of ignore that too.

737
00:35:22,040 --> 00:35:24,960
Speaker 1: You can definitely calculate and escape velocity right or effectively

738
00:35:25,000 --> 00:35:28,320
Speaker 1: an energy beyond which the electron is free and below

739
00:35:28,320 --> 00:35:31,239
Speaker 1: which the electron is bound. So you can definitely calculate that.

740
00:35:31,320 --> 00:35:34,440
Speaker 1: You can ignore relativity, you can include relativity or whatever.

741
00:35:34,920 --> 00:35:37,480
Speaker 1: But in order to trap that electron forever so that

742
00:35:37,480 --> 00:35:40,480
Speaker 1: there's no chance that ever leaves, then you essentially need

743
00:35:40,520 --> 00:35:44,440
Speaker 1: an infinitely powerful electric force. You need an infinite amount

744
00:35:44,480 --> 00:35:46,840
Speaker 1: of charge to trap an electron that could effectively have

745
00:35:46,920 --> 00:35:47,680
Speaker 1: infinite energy.

746
00:35:49,640 --> 00:35:52,440
Speaker 3: So would that mean that my electric black hole is

747
00:35:52,520 --> 00:35:54,360
Speaker 3: infinitely big or infinitely small?

748
00:35:57,760 --> 00:35:59,200
Speaker 1: It would be infinitely charged.

749
00:35:59,640 --> 00:36:02,080
Speaker 3: Oh does it have to be in constily charged or

750
00:36:02,080 --> 00:36:04,760
Speaker 3: could it just be a charge but infinitely dense.

751
00:36:05,000 --> 00:36:07,480
Speaker 1: You might imagine bringing the electron like really really close

752
00:36:07,520 --> 00:36:10,600
Speaker 1: to that charge so that the electric force gets really powerful,

753
00:36:10,640 --> 00:36:13,359
Speaker 1: because the electric force also gets powerful as things get

754
00:36:13,400 --> 00:36:16,359
Speaker 1: really close together. But again, these are quantum objects. There's

755
00:36:16,360 --> 00:36:19,640
Speaker 1: always like a minimum effective radius. It's not really an orbit,

756
00:36:19,680 --> 00:36:22,040
Speaker 1: but this is like a mean distance from the center

757
00:36:22,160 --> 00:36:25,120
Speaker 1: for the ground state, and so that effectively limits how

758
00:36:25,160 --> 00:36:28,000
Speaker 1: powerful these things can get. Like there's a reason the

759
00:36:28,040 --> 00:36:30,560
Speaker 1: hydrogen atom has a ground state and the electron is

760
00:36:30,560 --> 00:36:33,640
Speaker 1: not closer to it. It can't settle any closer, and

761
00:36:33,680 --> 00:36:36,680
Speaker 1: that effectively bounds like how strong the force can get.

762
00:36:37,080 --> 00:36:40,960
Speaker 3: Oh Man, So you're seeing quantum mechanics ruins all the time.

763
00:36:42,239 --> 00:36:45,080
Speaker 1: Like usual, But you also have another question about like

764
00:36:45,200 --> 00:36:48,680
Speaker 1: why can't we describe the other forces in terms of curvature?

765
00:36:48,840 --> 00:36:51,319
Speaker 1: And there are people working on that, people wondering like, well,

766
00:36:51,520 --> 00:36:54,839
Speaker 1: what if electromagnetism actually is curvature but not in our

767
00:36:54,920 --> 00:36:57,920
Speaker 1: three D space? What if it's curvature in like additional

768
00:36:58,000 --> 00:37:01,319
Speaker 1: spatial dimensions. And nobody's really made that theory work, but

769
00:37:01,360 --> 00:37:04,360
Speaker 1: it's really fun to think about how electromagnetism might be

770
00:37:04,440 --> 00:37:07,560
Speaker 1: like curvature in other ways that we can't see it yet.

771
00:37:08,000 --> 00:37:10,400
Speaker 1: And even in that theory, you might be able to

772
00:37:10,400 --> 00:37:13,359
Speaker 1: describe electromagnetism as curvature, and you might wonder like can

773
00:37:13,440 --> 00:37:16,640
Speaker 1: I make event horizons in those other dimensions, but then

774
00:37:16,680 --> 00:37:19,240
Speaker 1: you wouldn't be making event horizons in our three D space,

775
00:37:19,280 --> 00:37:20,920
Speaker 1: which I think is really what the question was.

776
00:37:21,200 --> 00:37:22,919
Speaker 3: So then it would be sort of like a black hole.

777
00:37:22,920 --> 00:37:24,040
Speaker 3: But the inn other dimensions.

778
00:37:24,120 --> 00:37:26,160
Speaker 1: It's pretty hard to think about, but it would be

779
00:37:26,239 --> 00:37:29,240
Speaker 1: curvature in other dimensions, and you might have event horizons

780
00:37:29,320 --> 00:37:32,880
Speaker 1: in those dimensions, but not in our dimensions, So pretty

781
00:37:32,920 --> 00:37:33,560
Speaker 1: wonky stuff.

782
00:37:33,600 --> 00:37:36,240
Speaker 3: There'd be holes in our black hole, is basically.

783
00:37:35,840 --> 00:37:36,640
Speaker 1: What you're saying.

784
00:37:36,960 --> 00:37:40,720
Speaker 3: Yeah, exactly, all right, Well that's an interesting answer for Derek.

785
00:37:41,160 --> 00:37:43,520
Speaker 3: Now let's get to our last question of today, and

786
00:37:43,600 --> 00:37:47,200
Speaker 3: it's about the air we breathe and where does part

787
00:37:47,200 --> 00:37:49,640
Speaker 3: of it come from? So let's dig into that question,

788
00:37:49,719 --> 00:38:05,440
Speaker 3: but first let's take a quick break. We're answering listener

789
00:38:05,480 --> 00:38:08,280
Speaker 3: questions here today and our last question comes from Steve

790
00:38:08,440 --> 00:38:09,800
Speaker 3: paren from Quebec.

791
00:38:10,719 --> 00:38:14,960
Speaker 2: Hi, Daniel and Jorge, this is Steve Pargan from Quebec, Canada.

792
00:38:16,040 --> 00:38:18,920
Speaker 2: My question is where is all the nitrogen in our

793
00:38:19,000 --> 00:38:24,719
Speaker 2: atmosphere coming from? And what role does it play? Amazing podcast, guys,

794
00:38:24,719 --> 00:38:25,799
Speaker 2: I love it, Thank you.

795
00:38:26,840 --> 00:38:30,759
Speaker 3: All right, A pretty straightforward question here, Where does all

796
00:38:30,800 --> 00:38:34,200
Speaker 3: the nitrogen in our atmosphere come from and what role

797
00:38:34,239 --> 00:38:34,759
Speaker 3: does it play?

798
00:38:34,920 --> 00:38:37,560
Speaker 1: Yeah, nitrogen is a big deal on Earth. Like, most

799
00:38:37,600 --> 00:38:40,760
Speaker 1: of the atmosphere is nitrogen. You take a deep breath,

800
00:38:41,040 --> 00:38:44,040
Speaker 1: you think yourself as a gulping oxygen, but it's mostly

801
00:38:44,160 --> 00:38:47,480
Speaker 1: nitrogen that you're breathing in, which is kind of weird.

802
00:38:47,640 --> 00:38:49,799
Speaker 3: Well, what do you mean mostly? What are the percentages?

803
00:38:50,239 --> 00:38:54,000
Speaker 1: It's almost eighty percent of the air is nitrogen.

804
00:38:53,600 --> 00:38:57,720
Speaker 3: Eighty percent by like a volume mass or adams.

805
00:38:57,440 --> 00:38:59,920
Speaker 1: It's seventy eight percent by mass.

806
00:39:00,800 --> 00:39:02,960
Speaker 3: And how much of it is oxygen? So it's like

807
00:39:03,040 --> 00:39:04,520
Speaker 3: most of the air is nitrogen.

808
00:39:04,800 --> 00:39:07,480
Speaker 1: It's seventy eight percent by quantity.

809
00:39:07,160 --> 00:39:09,360
Speaker 3: You mean by volume or what do you mean by

810
00:39:09,440 --> 00:39:11,200
Speaker 3: quantity like number of atoms?

811
00:39:11,440 --> 00:39:14,239
Speaker 1: Yeah, like number of molecules. Actually, if you count it up,

812
00:39:14,440 --> 00:39:16,360
Speaker 1: if you take like a cubic meter of air and

813
00:39:16,400 --> 00:39:19,360
Speaker 1: you count all the molecules in it, seventy eight percent

814
00:39:19,360 --> 00:39:21,719
Speaker 1: of those are nitrogen and twenty one percent of those

815
00:39:21,760 --> 00:39:22,440
Speaker 1: are oxygen.

816
00:39:22,680 --> 00:39:23,920
Speaker 3: Oh, no, hydrogen.

817
00:39:24,080 --> 00:39:27,480
Speaker 1: There's almost no hydrogen in the atmosphere because it's very volatile.

818
00:39:27,480 --> 00:39:30,320
Speaker 1: Any hydrogen will react with the oxygen and make water.

819
00:39:30,520 --> 00:39:32,200
Speaker 3: So where did all this nigrogen come from?

820
00:39:32,280 --> 00:39:34,239
Speaker 1: Yeah, it's a really fun question. It goes back to

821
00:39:34,280 --> 00:39:36,799
Speaker 1: the whole origin of like why we have an atmosphere

822
00:39:36,800 --> 00:39:39,920
Speaker 1: in the first place, because it's kind of weird. You

823
00:39:39,960 --> 00:39:42,359
Speaker 1: know that we have enough gravity to like hold this

824
00:39:42,480 --> 00:39:47,239
Speaker 1: little super thin envelope of gas around the planet. And

825
00:39:47,280 --> 00:39:49,160
Speaker 1: if you think about how the planet came to be,

826
00:39:49,760 --> 00:39:51,920
Speaker 1: it's not clear, like why we have an atmosphere that

827
00:39:51,960 --> 00:39:55,200
Speaker 1: survived the formation of the Solar System, because as things

828
00:39:55,200 --> 00:39:57,520
Speaker 1: were condensing very early in the Solar System, it was

829
00:39:57,520 --> 00:40:00,200
Speaker 1: a very volatile place. Like first of all, we're in

830
00:40:00,239 --> 00:40:03,080
Speaker 1: the Inner Solar System, which means we're pretty close to

831
00:40:03,120 --> 00:40:06,000
Speaker 1: the Sun, and so most of the hydrogen in the

832
00:40:06,000 --> 00:40:08,319
Speaker 1: Inner Solar System was gobbled up by the Sun. Like

833
00:40:08,360 --> 00:40:11,400
Speaker 1: the Sun has huge gravity. The reason that Earth was

834
00:40:11,440 --> 00:40:14,480
Speaker 1: formed is because it's not hydrogen. It's because it's rocky,

835
00:40:14,840 --> 00:40:18,120
Speaker 1: had like enough gravity to form its own little gravitational

836
00:40:18,160 --> 00:40:20,920
Speaker 1: well and cluster stuff together before it all got gobbled

837
00:40:21,000 --> 00:40:23,640
Speaker 1: up by the Sun. But that tends to gather together

838
00:40:23,719 --> 00:40:26,080
Speaker 1: heavy things like rocks and metal, right, chunks of iron

839
00:40:26,080 --> 00:40:29,120
Speaker 1: floating in space, not clouds of gas, most of which

840
00:40:29,160 --> 00:40:31,840
Speaker 1: fell into the Sun. Some of it did form with

841
00:40:31,920 --> 00:40:34,520
Speaker 1: the Earth. But then when the Sun started fusing, it

842
00:40:34,640 --> 00:40:38,440
Speaker 1: created all this intense radiation and blasted away our atmosphere.

843
00:40:38,800 --> 00:40:40,960
Speaker 1: So we might have had like a very thin hydrogen

844
00:40:40,960 --> 00:40:44,560
Speaker 1: atmosphere to begin with, but then most of that got

845
00:40:44,600 --> 00:40:48,319
Speaker 1: lost due to the solar radiation and then also collisions

846
00:40:48,360 --> 00:40:50,960
Speaker 1: by heavy stuff, like the formation of the Moon was

847
00:40:51,040 --> 00:40:54,400
Speaker 1: due to this collision with a protoplanet and that probably

848
00:40:54,600 --> 00:40:56,480
Speaker 1: destroyed all the atmosphere we had initially.

849
00:40:57,800 --> 00:41:00,480
Speaker 3: But I guess a deeper question is where it did

850
00:41:00,560 --> 00:41:03,480
Speaker 3: all come from originally, Like it just got form inside

851
00:41:03,480 --> 00:41:06,440
Speaker 3: the Sun like all the other heavy elements in previous

852
00:41:07,160 --> 00:41:09,799
Speaker 3: iterations of the Sun or supernova or what.

853
00:41:10,239 --> 00:41:12,560
Speaker 1: All the nitrogen and everything in our Solar system that

854
00:41:12,680 --> 00:41:16,279
Speaker 1: isn't hydrogen was not made by our star, right, All

855
00:41:16,320 --> 00:41:18,720
Speaker 1: that was made by previous stars. So like the deeper

856
00:41:18,800 --> 00:41:21,719
Speaker 1: history is that we have mostly hydrogen formed in very

857
00:41:21,800 --> 00:41:24,960
Speaker 1: very early universe, tiny tiny trace amounts of helium, and

858
00:41:24,960 --> 00:41:26,799
Speaker 1: then you have to wait for stars to be born

859
00:41:27,200 --> 00:41:29,800
Speaker 1: hundreds of millions of years later to turn that hydrogen

860
00:41:29,840 --> 00:41:33,120
Speaker 1: into heavier stuff. And so that nitrogen that you're breathing

861
00:41:33,200 --> 00:41:36,320
Speaker 1: right now was made at the heart of stars previous

862
00:41:36,400 --> 00:41:40,040
Speaker 1: generations which burned created that nitrogen inside them and then

863
00:41:40,120 --> 00:41:43,840
Speaker 1: blew up and spread those heavier elements, including nitrogen and

864
00:41:43,880 --> 00:41:45,919
Speaker 1: iron and copper and on carbon and all that good

865
00:41:45,920 --> 00:41:49,720
Speaker 1: stuff throughout the galaxy, and then that re coalesced into

866
00:41:49,760 --> 00:41:52,560
Speaker 1: our solar system. So all the nitrogen and the iron

867
00:41:52,600 --> 00:41:54,839
Speaker 1: and all that stuff in our bodies and in the

868
00:41:54,840 --> 00:41:57,640
Speaker 1: air and in the Earth was made by a different

869
00:41:57,719 --> 00:41:59,880
Speaker 1: star that no longer exists.

870
00:42:00,400 --> 00:42:03,080
Speaker 3: And it was made at the core of that previous star,

871
00:42:03,320 --> 00:42:04,360
Speaker 3: or when it exploded.

872
00:42:04,680 --> 00:42:06,799
Speaker 1: The stuff that's iron or lighter was made to the

873
00:42:06,800 --> 00:42:09,640
Speaker 1: core of that stars made by fusion, because when you

874
00:42:09,680 --> 00:42:12,920
Speaker 1: fuse two lighter elements together, you release energy. But that's

875
00:42:12,960 --> 00:42:15,920
Speaker 1: only true up to making iron beyond iron, When you

876
00:42:15,920 --> 00:42:18,919
Speaker 1: fuse stuff together, it costs energy. So if a star

877
00:42:19,000 --> 00:42:21,160
Speaker 1: starts to do that, it begins to dim and like

878
00:42:21,360 --> 00:42:24,680
Speaker 1: steals away the energy. And stars need that energy to

879
00:42:24,719 --> 00:42:27,560
Speaker 1: survive because they're fighting against gravity. Gravity is trying to

880
00:42:27,560 --> 00:42:29,879
Speaker 1: compress them down into a black hole. And the only

881
00:42:29,920 --> 00:42:32,480
Speaker 1: reason the star survives for millions or billions of years

882
00:42:32,800 --> 00:42:36,360
Speaker 1: is that radiation pressure outwards that's created by the energy

883
00:42:36,400 --> 00:42:38,919
Speaker 1: released by fusion. If that goes away, then the star

884
00:42:39,000 --> 00:42:42,239
Speaker 1: starts to collapse, and so stars can't make a lot

885
00:42:42,280 --> 00:42:44,799
Speaker 1: of the heavier elements above iron. For that, you need

886
00:42:44,920 --> 00:42:47,200
Speaker 1: either the death of the star, the supernova which has

887
00:42:47,239 --> 00:42:51,520
Speaker 1: super dense conditions capable of creating those heavier elements, or

888
00:42:51,560 --> 00:42:54,399
Speaker 1: things later on like collisions of neutron stars to create

889
00:42:54,440 --> 00:42:57,600
Speaker 1: the heaviest elements. But nitrogen is made in the heart

890
00:42:57,719 --> 00:42:59,720
Speaker 1: of those stars during normal fusion.

891
00:43:00,920 --> 00:43:04,440
Speaker 3: So we're basically breathing dead stars. Every time you take a.

892
00:43:04,440 --> 00:43:08,480
Speaker 1: Breath, it's a gift from those stars.

893
00:43:08,680 --> 00:43:11,040
Speaker 3: You're basically breathing zombie star.

894
00:43:11,320 --> 00:43:14,920
Speaker 1: Yes, exactly, zombie star brains. Take a deep breath.

895
00:43:16,120 --> 00:43:21,200
Speaker 3: Yeah, h smells delicious, smells like brains. So the previous

896
00:43:21,239 --> 00:43:24,080
Speaker 3: star made the It was floating around just like all

897
00:43:24,120 --> 00:43:26,920
Speaker 3: the hydrogen and carbon and dust and rocks that was

898
00:43:26,960 --> 00:43:30,880
Speaker 3: made by previous stars when our Sun started burning. And

899
00:43:30,920 --> 00:43:33,040
Speaker 3: then how did it end up on Earth or is

900
00:43:33,080 --> 00:43:35,719
Speaker 3: it spread out all around the Solar System?

901
00:43:36,040 --> 00:43:39,040
Speaker 1: It's all over the Solar System. Nitrogen is everywhere, It's

902
00:43:39,120 --> 00:43:42,960
Speaker 1: not just on Earth. And the nitrogen in our atmosphere

903
00:43:43,160 --> 00:43:46,279
Speaker 1: ended up on Earth in an interesting way. Number One,

904
00:43:46,360 --> 00:43:49,560
Speaker 1: it came from the bombardment of the Earth by like

905
00:43:49,640 --> 00:43:53,600
Speaker 1: comets and asteroids that had like frozen nitrogen in them,

906
00:43:53,760 --> 00:43:55,320
Speaker 1: and so we think, like a lot of the water

907
00:43:55,400 --> 00:43:58,279
Speaker 1: on Earth may have come from comets, the same thing

908
00:43:58,320 --> 00:44:02,840
Speaker 1: is true of nitrogen. The early Earth was blasted clean. Essentially,

909
00:44:02,880 --> 00:44:05,680
Speaker 1: it was just a bare rock because of the solar radiation.

910
00:44:06,200 --> 00:44:08,759
Speaker 1: But then it got a second atmosphere due to collisions

911
00:44:08,800 --> 00:44:12,920
Speaker 1: and also because of nitrogen and other gases trapped inside

912
00:44:13,000 --> 00:44:16,880
Speaker 1: the Earth which escaped out due to like volcanoes. You know,

913
00:44:16,880 --> 00:44:18,680
Speaker 1: you have a lot of these gases in the early Earth,

914
00:44:18,719 --> 00:44:20,759
Speaker 1: and as the Earth is settling, the heavy stuff goes

915
00:44:20,800 --> 00:44:23,200
Speaker 1: down to the core and the lighter stuff rises in

916
00:44:23,239 --> 00:44:26,080
Speaker 1: the mantle, and then some of that escapes through cracks

917
00:44:26,080 --> 00:44:29,600
Speaker 1: in the Earth. So volcanoes and the bombardment of asteroids

918
00:44:29,960 --> 00:44:34,560
Speaker 1: created our second atmosphere, which was mostly nitrogen and carbon dioxide.

919
00:44:34,640 --> 00:44:36,080
Speaker 1: So that's where the nitrogen comes.

920
00:44:35,960 --> 00:44:40,960
Speaker 3: From, and then eventually we got oxygen. But I guess

921
00:44:41,280 --> 00:44:45,080
Speaker 3: the second part of these question is what a role

922
00:44:45,120 --> 00:44:48,040
Speaker 3: does nitrogen play? Like do our bodies need a nitrogen

923
00:44:48,160 --> 00:44:49,319
Speaker 3: or do we just ignore it?

924
00:44:49,320 --> 00:44:53,400
Speaker 1: Mostly? Yeah, it's definitely not inert. Nitrogen plays a really

925
00:44:53,400 --> 00:44:57,080
Speaker 1: important role in the life cycle here on Earth, Like

926
00:44:57,239 --> 00:44:59,680
Speaker 1: plants need nitrogen. It's a crucial part of a lot

927
00:44:59,680 --> 00:45:02,040
Speaker 1: of the you know acids, and so in order for

928
00:45:02,080 --> 00:45:05,200
Speaker 1: plants to grow, you need nitrogen in the soil, a

929
00:45:05,239 --> 00:45:08,240
Speaker 1: big component of like fertilizer that people are constantly putting

930
00:45:08,280 --> 00:45:11,200
Speaker 1: onto their plants, farmers and pour huge amounts of it.

931
00:45:11,480 --> 00:45:13,520
Speaker 1: The reason you put manure on fields is that it

932
00:45:13,600 --> 00:45:17,200
Speaker 1: has nitrogen in it and other stuff. So plants need

933
00:45:17,200 --> 00:45:19,600
Speaker 1: this nitrogen in order to grow. And there are these

934
00:45:19,600 --> 00:45:22,840
Speaker 1: bacteria that will breathe the nitrogen from the atmosphere and

935
00:45:22,880 --> 00:45:25,919
Speaker 1: then basically make it available for the plants. So there's

936
00:45:25,920 --> 00:45:29,480
Speaker 1: a whole complicated nitrogen cycle that involves like these nitrogen

937
00:45:29,480 --> 00:45:32,640
Speaker 1: fixing bacteria and then plants using it to grow, and

938
00:45:32,719 --> 00:45:35,120
Speaker 1: animals eating it and then pooping it back out into

939
00:45:35,200 --> 00:45:37,920
Speaker 1: the ground. And it's a very complex cycle, but it's

940
00:45:37,920 --> 00:45:40,160
Speaker 1: definitely not inert It's a huge part of life on

941
00:45:40,160 --> 00:45:41,239
Speaker 1: Earth right right.

942
00:45:41,239 --> 00:45:43,000
Speaker 3: And I just want to take a quick moment here

943
00:45:43,000 --> 00:45:44,520
Speaker 3: to note that you were the first one to bring

944
00:45:44,640 --> 00:45:46,360
Speaker 3: up poop in this episode, not me.

945
00:45:48,440 --> 00:45:50,760
Speaker 1: Is that something you keep track of who says poop first?

946
00:45:53,360 --> 00:45:55,680
Speaker 3: I'm just saying sometimes they get you know, accused of.

947
00:45:57,440 --> 00:46:00,520
Speaker 1: Cultural language is down. Yeah, Well you know that's the

948
00:46:00,520 --> 00:46:02,840
Speaker 1: conversation we have at my house all the time because

949
00:46:02,880 --> 00:46:06,120
Speaker 1: my wife works on the gut microbiome, like literally, what's

950
00:46:06,160 --> 00:46:09,080
Speaker 1: happening inside your guts? And so the kids are always

951
00:46:09,080 --> 00:46:11,440
Speaker 1: timing like how long till mom brings up poop at

952
00:46:11,480 --> 00:46:14,839
Speaker 1: the dinner table? Oh boy? And it's never very long.

953
00:46:15,480 --> 00:46:17,480
Speaker 3: May should you just call it nigrogen instead of poop

954
00:46:20,080 --> 00:46:24,759
Speaker 3: nigrogen rich content. They'll spare your appetites.

955
00:46:25,080 --> 00:46:26,600
Speaker 1: We're just fertilizing the conversation.

956
00:46:27,239 --> 00:46:29,279
Speaker 3: Yeah, you just want to make it more fregrant. But

957
00:46:29,440 --> 00:46:33,480
Speaker 3: I guess why is nigrogen important and biological processes? Is

958
00:46:33,520 --> 00:46:36,279
Speaker 3: it something There's something special about that molecule, you know,

959
00:46:36,280 --> 00:46:38,640
Speaker 3: because carbon has some special things about it that make

960
00:46:38,719 --> 00:46:42,480
Speaker 3: it kind of crucial to life. Is nudigen similar?

961
00:46:42,920 --> 00:46:45,160
Speaker 1: Well, I think you're getting pretty deep into the chemistry here.

962
00:46:45,560 --> 00:46:48,520
Speaker 1: You know, the amino acids are the basic building blocks

963
00:46:48,520 --> 00:46:52,040
Speaker 1: of life, and having different kinds of atoms there, it

964
00:46:52,080 --> 00:46:56,239
Speaker 1: gives you different options, different things you can build. But yeah,

965
00:46:56,320 --> 00:46:58,799
Speaker 1: dot dot dot chemistry. I guess.

966
00:47:00,680 --> 00:47:01,960
Speaker 3: To be a Wikipedia later.

967
00:47:04,800 --> 00:47:07,040
Speaker 1: I mean, nitigen is already at the edge of my

968
00:47:07,120 --> 00:47:10,200
Speaker 1: ability to think about things. There's so many protons there,

969
00:47:10,239 --> 00:47:13,240
Speaker 1: it's crazy and then you have it connected.

970
00:47:12,880 --> 00:47:14,960
Speaker 3: With another your brain would explode.

971
00:47:15,080 --> 00:47:18,000
Speaker 1: Yeah, exactly, too many integrals from me.

972
00:47:18,000 --> 00:47:20,239
Speaker 3: For as a physicist zombie. You just have to throw

973
00:47:20,280 --> 00:47:24,040
Speaker 3: some chemistry questions at them, absolutely, and then their brains

974
00:47:24,040 --> 00:47:24,799
Speaker 3: will explode.

975
00:47:24,960 --> 00:47:27,680
Speaker 1: Yes, chemistry is our kryptonite for sure. And they don't

976
00:47:27,680 --> 00:47:29,680
Speaker 1: even have to be that hard, just like my high

977
00:47:29,680 --> 00:47:33,319
Speaker 1: schoolers ap chemistry questions. Whoa headache? Time?

978
00:47:33,600 --> 00:47:33,880
Speaker 2: Right?

979
00:47:34,000 --> 00:47:34,080
Speaker 4: Right?

980
00:47:34,160 --> 00:47:40,839
Speaker 3: Hey Daniel, what's up? Regardless number big Welcome to Jorge

981
00:47:40,920 --> 00:47:47,080
Speaker 3: explains the universe. All right, Well that's the answer for Steve,

982
00:47:47,640 --> 00:47:50,160
Speaker 3: which is that the nigogen we're all breathing, eighty percent

983
00:47:50,200 --> 00:47:53,760
Speaker 3: of the air we're breathing, came from a debt previous

984
00:47:53,800 --> 00:47:56,840
Speaker 3: star in our solar system. Then it got formed with

985
00:47:56,880 --> 00:47:59,080
Speaker 3: the rest of the Earth and the rocks and the

986
00:47:59,120 --> 00:48:02,719
Speaker 3: other elements, and that's how we're breathing it today, that's right,

987
00:48:02,840 --> 00:48:06,240
Speaker 3: possibly from comments, possibly from the earth burping.

988
00:48:06,360 --> 00:48:08,960
Speaker 1: Yeah, exactly. And there's been some people doing really interesting

989
00:48:09,000 --> 00:48:12,280
Speaker 1: studies to try to understand exactly where this nitrogen came from,

990
00:48:12,600 --> 00:48:14,960
Speaker 1: because not all nitrogen is the same. Some of them

991
00:48:15,000 --> 00:48:17,600
Speaker 1: have different isotope ratios, and you can tell like, was

992
00:48:17,600 --> 00:48:19,680
Speaker 1: it formed in the Outer Solar System or the Inner

993
00:48:19,719 --> 00:48:23,040
Speaker 1: Solar System, the molecules, not the pure nitrogen which was

994
00:48:23,080 --> 00:48:26,360
Speaker 1: made in the stars. And so there are these studies

995
00:48:26,360 --> 00:48:28,200
Speaker 1: that tell us that some of the nitrogen on Earth

996
00:48:28,239 --> 00:48:30,359
Speaker 1: came from the Inner Solar System and some definitely came

997
00:48:30,400 --> 00:48:32,920
Speaker 1: from the Outer Solar System. So it's a similar question

998
00:48:33,000 --> 00:48:34,920
Speaker 1: to like where did our water come from?

999
00:48:35,160 --> 00:48:38,120
Speaker 3: All right, well, three awesome questions here today. Thanks to

1000
00:48:38,440 --> 00:48:41,080
Speaker 3: all of our listeners who sent in their questions.

1001
00:48:40,960 --> 00:48:43,640
Speaker 1: And thanks to everybody who asks questions. Please don't be shy.

1002
00:48:43,760 --> 00:48:46,600
Speaker 1: Write to us two questions at Daniel and Jorge dot com.

1003
00:48:46,640 --> 00:48:48,120
Speaker 1: You'll definitely hear back from us.

1004
00:48:48,320 --> 00:48:51,440
Speaker 3: We hope you enjoyed that. Thanks for listening, See you

1005
00:48:51,480 --> 00:48:51,959
Speaker 3: next time.

1006
00:48:56,960 --> 00:48:59,719
Speaker 1: For more science and curiosity, come find us on social

1007
00:48:59,760 --> 00:49:04,760
Speaker 1: media where we answer questions and post videos. We're on Twitter, Discord, Insta,

1008
00:49:04,880 --> 00:49:08,600
Speaker 1: and now TikTok. Thanks for listening and remember that Daniel

1009
00:49:08,640 --> 00:49:12,040
Speaker 1: and Jorge Explain the Universe is a production of iHeartRadio.

1010
00:49:12,360 --> 00:49:17,520
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1011
00:49:17,640 --> 00:49:20,000
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