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Speaker 1: Hey, Daniel, what's the latest news in physics?

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Speaker 2: We still don't know how anything works. Newsflash.

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Speaker 1: That's not really news, is it.

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Speaker 2: It's true every single morning.

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Speaker 1: There's been no new discoveries in the last week or so.

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Speaker 2: No, we learn stuff every year, but the fraction of

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Speaker 2: all knowledge we have remains approximately zero.

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Speaker 1: You mean compared to the infinity of the universe or

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Speaker 1: how much you're already forgetting due to age.

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Speaker 2: I think both are true. The denominator is infinite and

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Speaker 2: the numerator is true. It's decaying with time, Yes, exactly.

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Speaker 2: I may have reached my peak smartness a few years ago.

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Speaker 1: Oh, I think I reached my peak smartness like when

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Speaker 1: I was five.

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Speaker 2: Maybe you should have retired then, man.

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Speaker 1: I wish I could have. Yeah, I could have been

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Speaker 1: playing golf for the last fifty years.

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Speaker 2: There you go, folks. Advice to all you five year

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Speaker 2: olds out there, what's the advice? Be rich and retire earlier.

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Speaker 1: I am Jorge, a cartoonist and the author of Oliver's.

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Speaker 2: Great Big Universe. Hi, I'm Daniel. I'm a particle physicist

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Speaker 2: and the professor at UC Irvine, and I don't plan

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Speaker 2: to ever retire.

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Speaker 1: What do you mean you'll have to like drag you

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Speaker 1: out of your office at some point, or you plan

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Speaker 1: to die in your office.

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Speaker 2: I plan to die in this job, though I haven't

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Speaker 2: actually decided where physically that will be.

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Speaker 1: I guess, Yeah, I guess you can work from work

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Speaker 1: and die from home. I guess. But really you don't

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Speaker 1: plan to ever, you know, not do physics.

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Speaker 2: As so long as I can keep teaching and thinking,

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Speaker 2: then yeah, I'll keep doing it.

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Speaker 3: Mmmm.

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Speaker 1: You don't believe in like making room for the next

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Speaker 1: generation of physicists.

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Speaker 2: They're all retiring at five. They don't need jobs.

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Speaker 1: Well, you need room for the four year olds, you know.

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Speaker 1: But anyways, Welcome to our podcast Daniel and Jorge Explain

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Speaker 1: the Universe, a production of iHeartRadio.

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Speaker 2: In which we make the whole universe our problem, to

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Speaker 2: figure it out, to explain it to you, to understand

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Speaker 2: how it all works, to break it down into its

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Speaker 2: tiniest little bits and make it make sense if at

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Speaker 2: all possible.

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Speaker 1: That's right. We try to retire the ignorance that we

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Speaker 1: have about our universe and the beautiful cosmos that we

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Speaker 1: all live in, and we try to make headway into

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Speaker 1: your brain to help you understand how it all works

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Speaker 1: and what it all means about our existence.

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Speaker 2: And step one to figuring it out is understanding what

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Speaker 2: we don't know is examining the questions we still have

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Speaker 2: in our minds. What is it that we want to

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Speaker 2: figure out? What can the usion do we have about

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Speaker 2: how things are fitting together? What topics remain completely unexplored

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Speaker 2: and unknown. And it's not just professional physicists and five

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Speaker 2: year olds asking questions about the universe. It's everybody. And

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Speaker 2: we want to encourage you, everybody out there who's listening,

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Speaker 2: who is curious about the nature of the universe, to

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Speaker 2: ask questions. Ask them of yourself, and if you can't

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Speaker 2: figure them out, ask them of us. Write them to

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Speaker 2: Questions at Danielandjorge dot com and you'll get an answer.

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Speaker 1: Yeah, Because, as we said many times, the process of science,

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Speaker 1: the process of discovery and finding knowledge out there, starts

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Speaker 1: with questions, starts with people being curious about what they

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Speaker 1: see and what they think they don't understand.

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Speaker 2: And if you write to us with your questions, you'll

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Speaker 2: get a reply at least even if it's not a

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Speaker 2: complete answer, Because some of these questions nobody knows the

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Speaker 2: answer to, so all we can do is fast forward

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Speaker 2: you to the current forefront of human.

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Speaker 1: Ignorance, right, because sometimes asking a question of a scientist

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Speaker 1: helps them come up with new questions, right, or think

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Speaker 1: of questions and new ways in their research. Right. Has

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Speaker 1: anybody ever written you and you're like, WHOA, I never

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Speaker 1: thought about that before.

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Speaker 2: People have definitely written to me with questions I've never

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Speaker 2: had myself, ideas I've never thought of all the time,

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Speaker 2: I don't know that any of them have like actually

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Speaker 2: spurred new research.

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Speaker 1: Or maybe like a new way to think about what

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Speaker 1: you're doing.

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Speaker 2: I think sometimes the way people ask questions forces me

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Speaker 2: to think about things in a new way. Sure, and

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Speaker 2: you know, always the process of teaching and explaining forces

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Speaker 2: you to examine your own understanding and shore it up

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Speaker 2: and make connections you didn't make before. So this whole

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Speaker 2: podcast is like deep in my understanding of physics because

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Speaker 2: I'm forced to go out there and make connections and

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Speaker 2: find explanations for things that I was pretty sure I understood.

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Speaker 2: But when you go to explain it, you can always

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Speaker 2: find holes in your understanding.

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Speaker 1: Yeah, it's all the big conversations and we try to

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Speaker 1: make all of you listeners part of the conversation here

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Speaker 1: in our podcast, because sometimes in our episodes we answer

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Speaker 1: questions that we yet from listeners like you.

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Speaker 2: As are right. Sometimes the questions that come in through

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Speaker 2: the inbox are fascinating or tricky or complicated, or I

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Speaker 2: just think everybody might enjoy hearing the answer, so we

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Speaker 2: select some to answer here on the podcast. Thank you

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Speaker 2: to everybody who sends in your questions.

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Speaker 1: So today on the podcast, we'll be tackling listener questions.

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Speaker 1: Number sixty one, So Daniel, we're back to numbering these sequentially?

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Speaker 1: Or is this still a random number with a secret

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Speaker 1: code in it?

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Speaker 2: This is not a random number with secret code.

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Speaker 1: No.

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Speaker 2: I like to be sequential because when people write in

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Speaker 2: and I tell them we're going to answer it on

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Speaker 2: the podcast, I like to tell them which episode to

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Speaker 2: wait for, So numbers are useful for that, though I

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Speaker 2: suppose I could name them. Also, this could be the

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Speaker 2: elephant episode, or we're going to have a Polka Dot

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Speaker 2: episode or whatever. Those are just as arbitrary as numbers. Yeah,

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Speaker 2: or or like random numbers too?

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Speaker 1: Right? This could be sixty one point seven four five three?

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Speaker 2: Sure? Why not?

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Speaker 1: Aren't extractional names? That's right? Or you give me like

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Speaker 1: Elon Muskin and name things with weird symbols in them.

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Speaker 1: Then we'd have to struggle to pronounce them. Yeah, I

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Speaker 1: guess it is a podcast. We have to read things

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Speaker 1: out loud, so we could.

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Speaker 2: Just give them weird sounds then you know.

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Speaker 1: Oh, there you go. This is listener questions number and

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Speaker 1: then but then you have to also have to write them,

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Speaker 1: so that might be Yeah, maybe we should just stick

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Speaker 1: the numbers. Wow, it's like numbers are useful integers. Yeah. Yeah,

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Speaker 1: all right, so sixty one. I feel like we've been

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Speaker 1: increasing these numbers because I feel like we just a

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Speaker 1: few weeks ago we were at number forty three.

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Speaker 2: Man, We've been doing about one a week for a

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Speaker 2: while now because we got so many more questions coming in.

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Speaker 1: MMM. And so our first question comes from Augustine, and

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Speaker 1: his question is about the gravity of black holes.

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Speaker 4: Hello, Danny on her head, this is your friend. I

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Speaker 4: have a crazy idea. We know that the gravity and

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Speaker 4: a black hole is so strong that it will reap

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Speaker 4: apart matter or what we call sometimes stagratification. My understanding

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Speaker 4: is that this will happen all the way until even

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Speaker 4: particles are pull apart. My brain now is thinking, okay,

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Speaker 4: what about quarts. If I'm correct, the stronger you pull

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Speaker 4: apart a couple of quarks, the stronger the force. And

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Speaker 4: when we put in a force to pull them apart,

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Speaker 4: we give them force enough to create a new one,

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Speaker 4: and they are always in pairs. So now we have

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Speaker 4: like four age sixteen and close quarts. So it could

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Speaker 4: be possible that inside black holes we have an infinite

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Speaker 4: machine of creating quarts that might even be so many

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Speaker 4: at some point that we create a new universe inside

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Speaker 4: a black hole. Or even more, what if all that

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Speaker 4: energy of the black hole turns into just quarts and

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Speaker 4: making the black hole disappear? Thank you?

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Speaker 1: All right? Really fun question. Basically, I think he's asking

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Speaker 1: can he make spaghetti out of quarks?

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Speaker 2: Well, you know all spaghetti is made out of quarks

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Speaker 2: and electrons, so yeah, but this is not a cooking show. Now,

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Speaker 2: I think he's asking a really hard question about what

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Speaker 2: happens to particles inside a black hole.

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Speaker 1: Now we're talking about black hole, so I suspect the

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Speaker 1: answer will be we have no idea. But Augustine is

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Speaker 1: sort of a friend of the podcast, right.

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Speaker 2: Yeah, that's right. Augustine has his own Spanish language podcast,

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Speaker 2: which you should go and check out Kurt Gasidad Scientifica.

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Speaker 2: It's excellent and he and I have been in conversation

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Speaker 2: about physics for several years and I think he wrote

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Speaker 2: this in to try to stump me.

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Speaker 1: Cool, So go ahead and check out that podcast, even

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Speaker 1: if you don't speak Spanish. I imagine it's interesting.

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Speaker 2: You'll either learn physics or Spanish.

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Speaker 1: Yeah, are both?

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Speaker 5: Oh my goodness. Yeah, all right, So the question is interesting.

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Speaker 5: I think the question is like what happens to a

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Speaker 5: particle as it goes into a black hole, Because we've

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Speaker 5: talked about before this idea of spa gutification. As you

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Speaker 5: get near a black hole, the intensity of the gravitational

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Speaker 5: feel is so high that it sort of rips you apart.

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Speaker 2: Right, Yeah, that's exactly right. Gravity is very very powerful

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Speaker 2: near a black hole. And if you have a physical extent,

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Speaker 2: if you're not just a point particle, like if you're

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Speaker 2: a little blob, then gravity on one side is going

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Speaker 2: to be stronger than gravity on the other side, and

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Speaker 2: that means you're getting pulled harder on one side, and

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Speaker 2: that's equivalent to being pulled apart. So, for example, if

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Speaker 2: you are near a black hole, and your feet are

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Speaker 2: closer than your head, then the black hole is trying

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Speaker 2: to pull you into spaghetti. So it's like trying to

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Speaker 2: pull your head off of your body and your feet

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Speaker 2: off of your ankles, because it's pulling on those things differently.

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Speaker 2: That's where spaghettification comes from. It's the tidal forces of

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Speaker 2: the black hole, not directly the strength of the gravity

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Speaker 2: of the black hole, but the difference in its strength

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Speaker 2: as you get closer or further.

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Speaker 1: Right, because gravity depends on distance, right, gravity gets stronger

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Speaker 1: the closer you are to the source, just like gravity

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Speaker 1: stronger here on Earth than it is out there in space.

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Speaker 1: But sometimes the difference can be so big that it

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Speaker 1: can be enough to rip you apart.

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Speaker 2: That's right. Technically, the Earth is trying to rip you

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Speaker 2: apart because as you stand on the surface, the gravity

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Speaker 2: on your feet is stronger than the gravity on your head,

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Speaker 2: but that difference is much weaker than the internal strength

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Speaker 2: of your body, and so you're able to hold yourself together.

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Speaker 2: But that's not true near a black hole, because not

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Speaker 2: only is the gravity stronger, but the differences are stronger

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Speaker 2: because gravity gets weaker much faster with distance.

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Speaker 1: Right, So it's super intense when you get close to

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Speaker 1: a black hole, and so like if you were to

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Speaker 1: jump in head first, you would get ripped apart. Now,

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Speaker 1: I think Augustine's question is what happens to a particle?

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Speaker 1: Does a particle get pulled apart? And maybe let's start

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Speaker 1: with an atom, like would an atom get pulled apart?

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Speaker 2: Yeah, it's a great question, and there's a couple of

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Speaker 2: competing issues here. Like number one, the tile forces depend

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Speaker 2: on you having a physical extent. The further apart you are,

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Speaker 2: the greater the distance between one side of you and

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Speaker 2: the other, the greater the difference and gravitational force will be.

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Speaker 2: So if there's no difference between one side of you

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Speaker 2: and the other, if you're like a point particle, then

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Speaker 2: there's no title forces. So title forces only apply to

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Speaker 2: things that are not point particles. And you're right, an atom,

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Speaker 2: for example, it's not a point particle, and so in

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Speaker 2: principle an atom could get pulled apart. But atoms are

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Speaker 2: so tiny, really really small, that the title forces are

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Speaker 2: going to be super duper tiny compared to like the

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Speaker 2: strength of the nuclear forces holding it together.

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Speaker 1: Right, I guess it's not just about how much gravity

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Speaker 1: there is it's about, like you said, the slope of

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Speaker 1: the gravity, or like the intensity of or how quickly

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Speaker 1: gravity is changing, Like the difference between one end of

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Speaker 1: the atom and the other end of the atom has

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Speaker 1: to be large enough to overcome those forces. But is

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Speaker 1: that possible? Though? It is kind of possible, isn't it?

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Speaker 2: In principle it is if you take the general relativistic

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Speaker 2: view of black holes a singularity, then as you get

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Speaker 2: closer and closer to the singularity, the curvature is just increasing.

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Speaker 2: And you might argue, well, the curvature has to be

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Speaker 2: crazy high for the title forces to compete with the

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Speaker 2: ternal strength of an atom. But then you can just

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Speaker 2: keep moving closer to the singularity to get arbitra early

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Speaker 2: strong gravity. And so, in principle, somewhere inside a black hole,

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Speaker 2: if there is a singularity there, you can get close

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Speaker 2: enough to it that the tidal forces should overcome the

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Speaker 2: strength of the bonds holding an atom together, and an

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Speaker 2: atom would get spaghetified.

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Speaker 1: So it wouldn't happen outside or as it goes in,

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Speaker 1: it would have to happen way in there.

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Speaker 2: Yeah, I did the calculation once, and outside the black

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Speaker 2: hole the gravity is not strong enough to spaghetify atoms.

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Speaker 2: But inside Again, if there is a singularity and we

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Speaker 2: don't know that there is, then in principle you could

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Speaker 2: get close enough inside.

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Speaker 1: Well, doesn't it depend on the size of the black hole,

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Speaker 1: Like the heavier and more intense the black hole is,

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Speaker 1: the less close you have to get to the center

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Speaker 1: to maybe rip apart an atom. Hmm.

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Speaker 2: Although if you can get arbitrary close then it doesn't

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Speaker 2: really matter what the mass of the black hole is

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Speaker 2: because you're decreasing that distance parameter. But yeah, for larger

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Speaker 2: black holes you don't have to get as close.

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Speaker 1: Did it even get to the center? Like, doesn't time

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Speaker 1: stop as you get to the edge or the surface

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Speaker 1: of a black hole?

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Speaker 2: Yeah, that's a little bit tricky. That depends on who's looking.

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Speaker 2: If you're in the outside of a black hole and

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Speaker 2: you're watching things fall in, then time slows down for

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Speaker 2: those objects according to you, and you never see them

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Speaker 2: fall into the black hole. But for the object itself,

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Speaker 2: time proceeds normally and they just fall in past the

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Speaker 2: event horizon and proceed towards the singularity and reach it

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Speaker 2: in finite time. General relativity is very tricky when it

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Speaker 2: comes to whose time we're talking about.

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Speaker 1: Right, But to the rest of the universe, it would

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Speaker 1: never happen.

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Speaker 2: Right, for the rest of the university, it would never

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Speaker 2: happen if it's the last thing you throw into the

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Speaker 2: black hole. As you approach the black hole, the black

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Speaker 2: holes of vent horizon actually grows out to meet you

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Speaker 2: because the power, the gravitational energy of the black hole

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Speaker 2: increases before the object crosses the event horizon. It's not

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Speaker 2: like it has to physically eat it and then it

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Speaker 2: pops out to be larger. So if you toss something

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Speaker 2: like a banana towards a black hole, it's event horizon

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Speaker 2: grows out or meet the banana, but never reaches it

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Speaker 2: unless you then throw an orange. That orange will pull

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Speaker 2: the event horizon out even further past the banana. So

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Speaker 2: the last thing to get thrown into a black hole

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Speaker 2: never actually reaches it, but earlier stuff will.

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Speaker 1: Will it like will the banana actually reach the center

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Speaker 1: of the black hole? Or are things frozen in time

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Speaker 1: inside the black hole?

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Speaker 2: Well, you can only answer these questions from the point

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Speaker 2: of view of some observer, and there's no observer on

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Speaker 2: the outside. They can see the inside of the black

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Speaker 2: hole from within the black hole, the banana reaches a singularity.

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Speaker 2: But I feel like Augustine is asking a question about

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Speaker 2: the interplay between the tidal forces and the strong nuclear

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Speaker 2: force inside that atom.

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Speaker 1: Right right, Well, we said that it would maybe pull

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Speaker 1: apart an atom and maybe even a cord, but only

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Speaker 1: if it gets close to the singularity. I guess. I

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Speaker 1: mean then now the question sort of hinges like, will

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Speaker 1: it ever get close to that singularity?

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Speaker 2: According to general relativity, things will approach the singularity, And

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Speaker 2: Augustine is asking about this interesting question that's trying to

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Speaker 2: balance this power of the black hole to pull basically

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Speaker 2: anything apart if it approaches a singularity, and the strong force,

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Speaker 2: which has this bizarre behavior that if you pull things apart,

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Speaker 2: it pops new particles out of the vacuum. And I

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Speaker 2: think he's wondering whether that's effectively creating an infinite amount

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Speaker 2: of mass.

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Speaker 1: Mmm, oh, I see, all right, let's dig into his

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Speaker 1: specific scenario. So now we're imagining it that a quark

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Speaker 1: somehow gets inside of a black hole and it does

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Speaker 1: make it close enough to this singularity that they would

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Speaker 1: get pulled apart, or.

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Speaker 2: I think imagine two quarks like you have a quark

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Speaker 2: antiquark pair. They're bound together into something like a pion,

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Speaker 2: or maybe you have three quarks within a proton, and

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Speaker 2: then those get pulled apart by the singularity. And when

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Speaker 2: those get pulled apart, there's now energy in that bond

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Speaker 2: which gets turned into mass in the form of new quarks. Mmm.

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Speaker 1: So then what would happen? So now you have a

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Speaker 1: third quark that suddenly appears next to the other two.

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Speaker 2: Yeah, actually you're going to get another pair of quarks.

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Speaker 2: So if you start, for example, with a quark antiquark pair,

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Speaker 2: and you pull them apart outside a black hole or

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Speaker 2: inside a black hole, with going to happen is that

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Speaker 2: there's a huge amount of energy stored in the strong

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Speaker 2: force between the two quarks. Because remember the strong force

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Speaker 2: is really weird, and the force between them doesn't decrease

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Speaker 2: with distance. As you increase the distance between the cork

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Speaker 2: and antiquark pair, the amount of energy in that bond

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Speaker 2: becomes enormous, and the universe prefers to convert that energy

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Speaker 2: back into mass, and it creates a new cork anti

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Speaker 2: cork pair, effectively reducing those distances. So you have like

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Speaker 2: cork antiquark now turns into cork antiquork cork antiquark.

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Speaker 1: So like they multiplied or they just sort of like

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Speaker 1: divided the energy between two.

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Speaker 2: Pairs, because I'm not sure what the difference is. Like,

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Speaker 2: you have one configuration with a lot of energy in

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Speaker 2: the bond. The next configuration, the one the universe prefers,

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Speaker 2: is to have lower energy in the bonds and have

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Speaker 2: more energy in the masses. The reason the universe prefers

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Speaker 2: that is that there's more possible configurations. That way, you

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Speaker 2: have more particles, they can get moved around a lot.

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Speaker 2: In general, the universe prefers to spread energy out because

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Speaker 2: it allows for more options. It's like an effective entropy.

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Speaker 1: Okay, so then the black hole would split the cork

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Speaker 1: pair and make four quarks. And now what happens next.

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Speaker 1: Then those four quarks would fall into the black hole.

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Speaker 1: Would they also get split?

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Speaker 2: Yep, those get split, and then you get more quarks,

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Speaker 2: and then those get split and you get more quarks.

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Speaker 1: But at some point, don't you start to dilute the energy?

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Speaker 1: Isn't each subsequent pair of quarks don't they have less

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Speaker 1: energy in their bonds?

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Speaker 2: Yeah? Exactly, And that's what happens in real life, like,

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Speaker 2: we do this at the Large Hadron Collider all the time.

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Speaker 2: We don't have a black hole yet, hopefully that we're

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Speaker 2: aware of. The lawyers require me to say. We create

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Speaker 2: quarks in it at quarks all the time, and we

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Speaker 2: create them in a way that they're flying apart. They

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Speaker 2: have a lot of velocity away from each other, and

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Speaker 2: so what happens is you get new pairs of quarks.

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Speaker 2: That energy is converted into mass, and eventually you got

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Speaker 2: a huge number of quark antiquark pairs and they're flying

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Speaker 2: away from each other, so that energy, that velocity gets

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Speaker 2: turned into mass. Effectively, what's happening here is something similar,

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Speaker 2: except you have gravitational energy. You're using the gravitational energy

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Speaker 2: of the black hole to basically pull the quarks apart.

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Speaker 2: That kinetic energy then gets turned into mass. So you're

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Speaker 2: turning the gravitational energy the black hole into mass.

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Speaker 1: So you're just sort of like churning energy around. You're

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Speaker 1: not creating new energy, you're not destroying energy. You know,

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Speaker 1: the energy still stays within the black hole. It's just that,

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Speaker 1: according to your theories, there's going to be a lot

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Speaker 1: of weird slashing around in there.

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Speaker 2: Yeah, exactly, and Augustine is wondering, like, does this turn

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Speaker 2: into an infinite amount of energy or where does this

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Speaker 2: energy come from? And the energy really comes from within

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Speaker 2: the black hole. It's just the gravitational energy of the

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Speaker 2: black hole. It's just like asking, hey, if you have

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Speaker 2: a particle near the edge of a black hole, doesn't

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Speaker 2: it accelerate as it gets towards the center of the

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Speaker 2: black hole? Where does that energy come from? That energy

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Speaker 2: just comes from the gravitational energy of the black hole.

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Speaker 2: It's converting the potential energy of the black hole into

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Speaker 2: kinetic energy of this particle. The thing about the black

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Speaker 2: hole is that doesn't change the overall energy of the

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Speaker 2: black hole. It still has the same total energy, which

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Speaker 2: is what in the end controls its gravitational power. So

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Speaker 2: it doesn't really matter what you do within the black hole.

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Speaker 2: Do you have quarks? Did you have the energy in

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Speaker 2: the bonds? You have it in the gravitational potential energy.

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Speaker 2: As you say, it's just sloshing around inside the black hole.

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Speaker 1: But do you get like an infinite number of quarks

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Speaker 1: being made or is there at some point does it

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Speaker 1: stop popping off these new quarks or is it that

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Speaker 1: at some point. You know, the courts you create have

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Speaker 1: so little energy to them that there's just not enough

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Speaker 1: to make new quarks.

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Speaker 2: It's a great question, and we don't actually know the

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Speaker 2: answer to it. In this simplistic model that I've drawn out,

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Speaker 2: where you have like a pure general relativity black hole

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Speaker 2: with an actual singularity in it, and then you have

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Speaker 2: these particles, you get an infinite number of quarks because

407
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Speaker 2: as you approach the singularity, there's always a place where

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Speaker 2: the new quarks are going to get rid apart to

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Speaker 2: make new quarks, to make more quarks. But the problem

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Speaker 2: there the infinity in the number of quarks comes from

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Speaker 2: the infinity in the singularity, which we don't think is physical.

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Speaker 2: So the real answer depends on knowing what's actually going

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Speaker 2: on inside a black hole, and the infinity in this

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Speaker 2: answer comes from the infinity and assuming that it's a singularity,

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Speaker 2: which is probably not true.

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Speaker 3: Mmm.

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Speaker 1: I see, so you're saying the answer is that we

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Speaker 1: don't know.

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Speaker 2: We didn't know.

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Speaker 1: We could just skipped the last twenty minutes. Daniel just

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Speaker 1: comes with my answer.

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Speaker 2: No, you were totally correct right off the bat, because

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Speaker 2: we don't know how gravity and quantum particles interact we

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Speaker 2: don't even know how to calculate gravity for quantum particles

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Speaker 2: that have uncertain locations. So the right answer depends on

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Speaker 2: figuring out quantum gravity, which we have not yet done.

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Speaker 1: Right, We don't even know if it'll make it to

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Speaker 1: the center, right, Like, we don't really know what happens

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Speaker 1: even beyond the event horizon.

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Speaker 2: Right, Yeah, exactly right. There are some theories that black

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Speaker 2: holes have no center, have no interiors, all just smeared

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Speaker 2: on this sphericle event horizon, and there is nothing in

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Speaker 2: the bulk. All the information is just encoded on a

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Speaker 2: two D surface, that the black hole is not actually

435
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Speaker 2: part of our universe.

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Speaker 1: Sounds like maybe the next question is not can you

437
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Speaker 1: make spaghetti out of quarks? Is can you make smir

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Speaker 1: out of quarts?

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Speaker 2: All Schmeer has quarts in it, and in fact, the

440
00:20:59,600 --> 00:21:02,879
Speaker 2: Germans have a kind of spread called quark, which is

441
00:21:02,920 --> 00:21:04,119
Speaker 2: some kind of yogrity spread.

442
00:21:05,160 --> 00:21:08,320
Speaker 1: It sounds like the Germans know the answer to this question.

443
00:21:08,359 --> 00:21:12,680
Speaker 2: Perhaps the answer is probably one really long German word.

444
00:21:12,800 --> 00:21:15,000
Speaker 1: Are there a German science podcast you've been on that

445
00:21:15,119 --> 00:21:20,199
Speaker 1: maybe could help us illuminate the topic? Here, you've been

446
00:21:20,240 --> 00:21:25,399
Speaker 1: on nine of them.

447
00:21:25,640 --> 00:21:27,600
Speaker 2: I'm going to leave you in the quantum superposition of

448
00:21:27,680 --> 00:21:31,480
Speaker 2: thinking that was nine englishman. I think that was just

449
00:21:31,520 --> 00:21:33,760
Speaker 2: a bad pun. I think it was a pretty good pun,

450
00:21:34,000 --> 00:21:34,920
Speaker 2: or a pretty good pun.

451
00:21:35,480 --> 00:21:37,760
Speaker 1: All right, Well, thank you Augustine for what do you

452
00:21:37,800 --> 00:21:40,399
Speaker 1: do in your podcast and also for sending us this question.

453
00:21:40,640 --> 00:21:43,280
Speaker 1: So now let's get to our next questions. We have

454
00:21:43,359 --> 00:21:47,560
Speaker 1: one here about golden asteroids and one about the effects

455
00:21:47,600 --> 00:21:51,280
Speaker 1: of gravitational waves on time, So let's get to those.

456
00:21:51,320 --> 00:22:06,880
Speaker 1: But first let's take a quick break where we're answering

457
00:22:07,240 --> 00:22:11,359
Speaker 1: listener questions here today on podcast number sixty one point

458
00:22:12,000 --> 00:22:14,800
Speaker 1: zero zero zero zero zero right now? Does a podcast

459
00:22:14,840 --> 00:22:17,400
Speaker 1: number have those decimals or is it a pure integer?

460
00:22:17,960 --> 00:22:21,680
Speaker 2: I think it gets rounded by our heart processing system.

461
00:22:22,000 --> 00:22:25,880
Speaker 1: I didn't know we had a process for rounding titles.

462
00:22:27,040 --> 00:22:29,720
Speaker 1: All right. Our next question comes from Mike, who comes

463
00:22:29,760 --> 00:22:30,800
Speaker 1: from Brooklyn.

464
00:22:31,960 --> 00:22:33,080
Speaker 2: Hi, Daniel, and Jorge.

465
00:22:33,880 --> 00:22:36,439
Speaker 6: Is it possible that somewhere in the universe there are

466
00:22:36,520 --> 00:22:39,480
Speaker 6: asteroids as big as our moon, made entirely of rare

467
00:22:39,520 --> 00:22:43,080
Speaker 6: metals such as gold or silver. How large an object

468
00:22:43,200 --> 00:22:46,679
Speaker 6: or system of such objects could there be? Thanks for

469
00:22:46,760 --> 00:22:50,320
Speaker 6: considering this question. You guys are the best and Katie

470
00:22:50,359 --> 00:22:54,200
Speaker 6: and Kelly are awesome co hosts too from Mike and Brooklyn.

471
00:22:55,359 --> 00:22:58,800
Speaker 1: All right, thank you, Mike. Pretty cool question. I guess

472
00:22:58,880 --> 00:23:02,240
Speaker 1: the question is could you have a giant gold asteroid

473
00:23:02,240 --> 00:23:02,600
Speaker 1: out there?

474
00:23:03,080 --> 00:23:05,960
Speaker 2: Yeah, and he wants a giant gold moon.

475
00:23:06,119 --> 00:23:08,320
Speaker 1: Moon or a gold planet. Is that possible?

476
00:23:11,119 --> 00:23:13,760
Speaker 2: I love the idea. Well it's a golden idea.

477
00:23:14,800 --> 00:23:18,199
Speaker 1: Well, let's dig into it. What are the chances that

478
00:23:18,359 --> 00:23:19,879
Speaker 1: pure gold things are out there.

479
00:23:20,040 --> 00:23:22,640
Speaker 2: There's definitely a lot of gold out there in the universe,

480
00:23:22,720 --> 00:23:24,639
Speaker 2: Like there is a lot of gold in the Earth,

481
00:23:25,119 --> 00:23:27,560
Speaker 2: and there are big blobs of gold in some sort

482
00:23:27,560 --> 00:23:31,439
Speaker 2: of like big heavy metallic asteroids. But the process by

483
00:23:31,480 --> 00:23:34,160
Speaker 2: which gold is made in the universe makes it, I think,

484
00:23:34,280 --> 00:23:37,560
Speaker 2: pretty unlikely to have like just a huge gold bar

485
00:23:37,760 --> 00:23:39,120
Speaker 2: floating out there in space.

486
00:23:39,320 --> 00:23:41,840
Speaker 1: Hmmm, what do you mean? How is gold made in

487
00:23:41,880 --> 00:23:42,399
Speaker 1: the universe?

488
00:23:42,480 --> 00:23:44,760
Speaker 2: Well, gold is a very heavy element, like many very

489
00:23:44,880 --> 00:23:48,120
Speaker 2: rare valuable elements, and it's so heavy that it can't

490
00:23:48,160 --> 00:23:50,160
Speaker 2: actually be made inside stars.

491
00:23:50,600 --> 00:23:50,719
Speaker 1: Right.

492
00:23:50,760 --> 00:23:52,840
Speaker 2: The brief history of the universe is that we started

493
00:23:52,880 --> 00:23:55,800
Speaker 2: out with almost all hydrogen, and then we formed stars

494
00:23:55,800 --> 00:23:58,520
Speaker 2: after a few hundred million years. Those stars are hot

495
00:23:58,560 --> 00:24:01,320
Speaker 2: and dense enough to do fusion which can make heavier elements,

496
00:24:01,480 --> 00:24:04,280
Speaker 2: but only up to about iron. Up to about iron,

497
00:24:04,320 --> 00:24:08,439
Speaker 2: when you fuse nuclei, you actually gain energy that releases energy.

498
00:24:08,480 --> 00:24:11,840
Speaker 2: It powers the star above iron. It costs energy to

499
00:24:11,880 --> 00:24:14,840
Speaker 2: do fusion, so you're cooling the star, you're consuming the

500
00:24:14,880 --> 00:24:18,719
Speaker 2: star's energy. So stars basically make elements up to about iron.

501
00:24:19,080 --> 00:24:22,840
Speaker 2: Heavier things than that require more specialized conditions, like the

502
00:24:22,880 --> 00:24:27,960
Speaker 2: collisions of neutron stars or supernova collapses that briefly create

503
00:24:27,960 --> 00:24:31,000
Speaker 2: the conditions necessary to consume that energy and make the

504
00:24:31,040 --> 00:24:32,199
Speaker 2: heavier elements m.

505
00:24:33,000 --> 00:24:34,960
Speaker 1: So you need a star to explode to make anything

506
00:24:34,960 --> 00:24:35,560
Speaker 1: above iron.

507
00:24:35,720 --> 00:24:38,760
Speaker 2: Anything above iron is made either in supernova so star

508
00:24:38,840 --> 00:24:42,200
Speaker 2: explosions or in neutron star collisions. And it used to

509
00:24:42,240 --> 00:24:44,640
Speaker 2: be that we thought it was mostly supernova but then

510
00:24:44,720 --> 00:24:47,960
Speaker 2: recently observations of neutron star collisions have sort of tilted

511
00:24:48,000 --> 00:24:50,040
Speaker 2: the balance, and now we think that probably most of

512
00:24:50,080 --> 00:24:53,800
Speaker 2: the gold in the universe is made in neutron star collisions.

513
00:24:54,000 --> 00:24:56,280
Speaker 2: How do we do that, Well, some neutron star collisions

514
00:24:56,280 --> 00:24:58,760
Speaker 2: they've observed in a couple of different ways, Like they've

515
00:24:58,760 --> 00:25:03,080
Speaker 2: seen the gravitational waves generated by these really intense massive

516
00:25:03,080 --> 00:25:06,639
Speaker 2: objects orbiting around each other and then eventually colliding, and

517
00:25:06,720 --> 00:25:10,040
Speaker 2: they also observed them astronomically, like they saw light from

518
00:25:10,080 --> 00:25:12,800
Speaker 2: the same event, and from that light they can measure

519
00:25:12,880 --> 00:25:15,840
Speaker 2: like how much gold was created, because gold, like every

520
00:25:15,840 --> 00:25:19,120
Speaker 2: other element, has a very special atomic fingerprint. It tends

521
00:25:19,160 --> 00:25:21,359
Speaker 2: to glow in certain wavelengths and give off light in

522
00:25:21,400 --> 00:25:23,720
Speaker 2: certain wavelengths. So they're able to measure the amount of

523
00:25:23,760 --> 00:25:27,280
Speaker 2: golden clouds around this neutron star collision by looking at

524
00:25:27,320 --> 00:25:29,640
Speaker 2: the light that came from it. It's this new era

525
00:25:29,720 --> 00:25:32,800
Speaker 2: of multi messenger astronomy where you see the same event

526
00:25:32,880 --> 00:25:35,840
Speaker 2: in two different sort of channels, and our understanding is

527
00:25:35,840 --> 00:25:38,920
Speaker 2: still pretty fuzzy, but it suggests that like huge amounts

528
00:25:38,920 --> 00:25:41,159
Speaker 2: of gold were made, like more than the mass of

529
00:25:41,200 --> 00:25:43,399
Speaker 2: the Earth is made in each of these collisions.

530
00:25:43,480 --> 00:25:46,440
Speaker 1: But I guess maybe a question is is it only

531
00:25:46,520 --> 00:25:51,439
Speaker 1: gold that gets made or is it all materials above,

532
00:25:51,960 --> 00:25:55,280
Speaker 1: you know, iron, get made in an equal amount or

533
00:25:55,359 --> 00:25:56,560
Speaker 1: is it sort of random.

534
00:25:56,480 --> 00:25:58,920
Speaker 2: It's not just gold that gets made. It's all these

535
00:25:58,920 --> 00:26:01,359
Speaker 2: heavy elements get made these kind of special events in

536
00:26:01,480 --> 00:26:06,080
Speaker 2: supernova implusions, in neutron star collisions, and it's definitely not equal, right,

537
00:26:06,119 --> 00:26:08,000
Speaker 2: Some of these things are easier to make because the

538
00:26:08,000 --> 00:26:10,119
Speaker 2: pathways for them to happen. Some of these things are

539
00:26:10,200 --> 00:26:12,600
Speaker 2: very very unstable, so even though you make them, they

540
00:26:12,600 --> 00:26:15,679
Speaker 2: disappear very rapidly and then decay down into other stuff.

541
00:26:16,119 --> 00:26:18,560
Speaker 2: We had a whole episode recently with Kelly about which

542
00:26:18,560 --> 00:26:21,000
Speaker 2: elements are more common in the universe, where we dig

543
00:26:21,040 --> 00:26:23,719
Speaker 2: into the science and the chemistry of that. But basically,

544
00:26:23,760 --> 00:26:26,399
Speaker 2: you're making everything possible and then only the stable stuff

545
00:26:26,400 --> 00:26:27,440
Speaker 2: sticks around very long.

546
00:26:28,320 --> 00:26:30,760
Speaker 1: Now, I know that in a supernova, I think what

547
00:26:30,840 --> 00:26:33,960
Speaker 1: happens is the inside of the star collapses and then

548
00:26:34,000 --> 00:26:36,119
Speaker 1: it bounces, and there's this huge shockwave. And as the

549
00:26:36,119 --> 00:26:38,919
Speaker 1: shockwave goes through the rest of the star, the outside

550
00:26:38,960 --> 00:26:42,280
Speaker 1: of the star, it basically squeezes things so much in

551
00:26:42,359 --> 00:26:45,720
Speaker 1: this shockwave that the neutrons and protons fuse together to

552
00:26:45,720 --> 00:26:47,080
Speaker 1: make these heavy elements.

553
00:26:47,160 --> 00:26:50,480
Speaker 2: Right mm hmm, yeah, that's right. You need very high

554
00:26:50,520 --> 00:26:53,160
Speaker 2: pressure and very high temperature in order to create these

555
00:26:53,280 --> 00:26:55,840
Speaker 2: heavy elements, and you need a lot of energy because

556
00:26:55,880 --> 00:26:58,879
Speaker 2: these processes absorb energy rather than creating it.

557
00:26:59,040 --> 00:27:01,520
Speaker 1: Now, is there a sort of a a propensity or

558
00:27:01,560 --> 00:27:06,679
Speaker 1: a tendency as the shockwave goes out to have phases

559
00:27:06,680 --> 00:27:09,000
Speaker 1: where it's making a lot of gold and then suddenly

560
00:27:09,040 --> 00:27:11,159
Speaker 1: it's making a ton of other elements and then suddenly

561
00:27:11,320 --> 00:27:13,080
Speaker 1: or is it all random all the time?

562
00:27:13,400 --> 00:27:15,880
Speaker 2: Yeah, that's a great question. It's not something we understand.

563
00:27:15,880 --> 00:27:18,920
Speaker 2: It's an area of current research exactly how that's happening.

564
00:27:19,440 --> 00:27:22,520
Speaker 2: This shockwave physics is very complicated because it's very sensitive

565
00:27:22,560 --> 00:27:24,719
Speaker 2: to a lot of the details. It's not like, on

566
00:27:24,760 --> 00:27:27,040
Speaker 2: average it ends up doing the same thing a little

567
00:27:27,040 --> 00:27:29,320
Speaker 2: bit hotter, a little bit colder, or the shockwave starts

568
00:27:29,320 --> 00:27:32,760
Speaker 2: here or starts there, and the conditions of the shockwave change.

569
00:27:33,040 --> 00:27:35,000
Speaker 2: So that's something people are working on right now. They

570
00:27:35,000 --> 00:27:38,879
Speaker 2: have these really complicated models of what's going on inside supernova.

571
00:27:38,960 --> 00:27:42,199
Speaker 1: So we don't know yet, but I imagine maybe the

572
00:27:42,240 --> 00:27:44,920
Speaker 1: conditions to make gold are maybe different than the conditions

573
00:27:44,920 --> 00:27:49,000
Speaker 1: to make lead or titanium, right, And so I imagine that

574
00:27:49,520 --> 00:27:51,920
Speaker 1: it's not just all random all the time. Maybe you know,

575
00:27:52,359 --> 00:27:54,640
Speaker 1: as the explosion goes out, maybe you get the conditions

576
00:27:54,640 --> 00:27:57,480
Speaker 1: for gold, and then suddenly the conditions change for something else, etc.

577
00:27:58,320 --> 00:28:00,720
Speaker 2: But it's also not clear that the condition are the

578
00:28:00,760 --> 00:28:03,760
Speaker 2: same across the whole star. The explosion might start in

579
00:28:03,800 --> 00:28:06,720
Speaker 2: one spot and then end in another. Spot, and so

580
00:28:06,760 --> 00:28:09,840
Speaker 2: you might simultaneously have different conditions across different parts of

581
00:28:09,840 --> 00:28:10,360
Speaker 2: the surface.

582
00:28:10,680 --> 00:28:12,840
Speaker 1: But I imagine there has to be a reason that

583
00:28:12,920 --> 00:28:17,200
Speaker 1: you find gold nuggets on Earth, right, like all those atoms,

584
00:28:17,280 --> 00:28:19,560
Speaker 1: those trillions of atoms in a gold nugget must have

585
00:28:19,560 --> 00:28:21,320
Speaker 1: been made at the same time. Or do you think

586
00:28:21,320 --> 00:28:24,840
Speaker 1: they were made separately in different phases and somehow they

587
00:28:24,880 --> 00:28:26,200
Speaker 1: got together at some point.

588
00:28:26,359 --> 00:28:28,680
Speaker 2: I think the formation of the gold that we find

589
00:28:28,760 --> 00:28:32,160
Speaker 2: here on Earth doesn't reflect how it is actually made

590
00:28:32,160 --> 00:28:34,800
Speaker 2: in the star. I think it more reflects the differentiation

591
00:28:34,920 --> 00:28:38,560
Speaker 2: process and the geology, the rock formation of what's happening

592
00:28:38,600 --> 00:28:42,040
Speaker 2: here on Earth. As the Earth cools. I think likely anyway,

593
00:28:42,160 --> 00:28:44,840
Speaker 2: gold made in these neutron stars comes out as a

594
00:28:44,920 --> 00:28:48,120
Speaker 2: huge fine spray, a mist, which then gets mixed out

595
00:28:48,160 --> 00:28:50,920
Speaker 2: into the universe, and you know these little granules that

596
00:28:50,960 --> 00:28:53,800
Speaker 2: then spread out. I don't think gold nuggets are formed

597
00:28:54,000 --> 00:28:55,800
Speaker 2: and then survive in that shape to be dug up.

598
00:28:56,480 --> 00:29:00,000
Speaker 1: You're saying, maybe it all gets made as dust, gold dust,

599
00:29:00,280 --> 00:29:02,080
Speaker 1: and then when the Earth was like a big ball

600
00:29:02,080 --> 00:29:06,520
Speaker 1: of lava, maybe gold doest sprinkle throughout it. The gold

601
00:29:06,600 --> 00:29:09,160
Speaker 1: doest somehow, you know, settled in the same spot and

602
00:29:09,200 --> 00:29:10,280
Speaker 1: then stuck together.

603
00:29:11,000 --> 00:29:13,600
Speaker 2: Yeah, that's exactly right. The Earth is formed from a

604
00:29:13,680 --> 00:29:15,880
Speaker 2: huge blob of gas and dust. Some of that is

605
00:29:16,040 --> 00:29:18,960
Speaker 2: little flecks of gold or heavier elements, and then as

606
00:29:19,000 --> 00:29:21,880
Speaker 2: that gets squeezed together into a planet, it gets hot, right,

607
00:29:21,920 --> 00:29:24,000
Speaker 2: and it gets molten, and then you have all sorts

608
00:29:24,040 --> 00:29:26,480
Speaker 2: of processes that happen. Like some of these elements are

609
00:29:26,480 --> 00:29:29,560
Speaker 2: called iron loving elements. They like to mix with iron

610
00:29:29,560 --> 00:29:32,200
Speaker 2: and they flow with the iron. So then as the

611
00:29:32,280 --> 00:29:35,360
Speaker 2: Earth is cooling, it differentiates and some of the heavy

612
00:29:35,400 --> 00:29:37,960
Speaker 2: things sink and some of the lighter things rise. And

613
00:29:38,000 --> 00:29:40,720
Speaker 2: the flow of those molten rocks and elements and oxides

614
00:29:40,760 --> 00:29:43,880
Speaker 2: and all sorts of complicated stuff determines where things end up.

615
00:29:44,040 --> 00:29:46,760
Speaker 2: And the big blobs that's why, like you get veins

616
00:29:46,840 --> 00:29:49,280
Speaker 2: of heavy metals or veins of copper here and there

617
00:29:49,440 --> 00:29:52,280
Speaker 2: comes from those molten flows, which then cool.

618
00:29:52,960 --> 00:29:55,240
Speaker 1: But you're saying that out there in space in the supernova,

619
00:29:55,600 --> 00:29:58,080
Speaker 1: we're not sure if these things get made as dust

620
00:29:58,280 --> 00:30:00,640
Speaker 1: or as layer chunks.

621
00:30:00,920 --> 00:30:02,640
Speaker 2: Yeah, we're not sure. I mean, I think it's most

622
00:30:02,840 --> 00:30:05,440
Speaker 2: likely because it's just the chaos and they energy this

623
00:30:05,520 --> 00:30:08,560
Speaker 2: process that it's spread out in terms of tiny granules,

624
00:30:08,840 --> 00:30:10,760
Speaker 2: But I don't know what the maximum size would be.

625
00:30:10,840 --> 00:30:13,920
Speaker 2: It's certainly possible that you get big ingots or even

626
00:30:14,080 --> 00:30:16,720
Speaker 2: enormous blobs. I mean, you can't rule out the possibility

627
00:30:16,840 --> 00:30:18,880
Speaker 2: that you're making like a blob the size of the

628
00:30:18,920 --> 00:30:22,200
Speaker 2: Los Angeles of pure gold. You know, quantum mechanically, anything

629
00:30:22,200 --> 00:30:22,840
Speaker 2: as possible.

630
00:30:22,880 --> 00:30:25,840
Speaker 1: So in principle it could be What about these neutron

631
00:30:25,920 --> 00:30:28,880
Speaker 1: star collisions. Is the mechanism the same like a shockwave

632
00:30:28,960 --> 00:30:32,040
Speaker 1: or do things it made from the soup of neutrons

633
00:30:32,080 --> 00:30:34,080
Speaker 1: and quarts that make up the stars.

634
00:30:34,400 --> 00:30:36,440
Speaker 2: Well, there definitely is a collision there and that creates

635
00:30:36,480 --> 00:30:39,680
Speaker 2: a shockwave through both neutron stars. Then they settle down

636
00:30:39,720 --> 00:30:42,360
Speaker 2: to form one bigger neutron star or a black hole

637
00:30:42,560 --> 00:30:44,600
Speaker 2: more likely if they're over the threshold now for a

638
00:30:44,640 --> 00:30:48,000
Speaker 2: neutron star to be stable, but we really don't understand

639
00:30:48,000 --> 00:30:50,640
Speaker 2: what's inside a neutron star and how that all works.

640
00:30:50,960 --> 00:30:53,320
Speaker 2: So we know that there's a process there that's capable

641
00:30:53,360 --> 00:30:55,720
Speaker 2: of creating these heavy elements, but we do not have

642
00:30:55,760 --> 00:30:58,040
Speaker 2: a detailed understanding of it. We don't even understand a

643
00:30:58,120 --> 00:31:00,600
Speaker 2: single stable neutron star, not to mention like two of

644
00:31:00,640 --> 00:31:04,120
Speaker 2: them smashing into each other, having complex shock waves bouncing

645
00:31:04,160 --> 00:31:04,840
Speaker 2: around inside.

646
00:31:05,200 --> 00:31:08,240
Speaker 1: Because I think neutron stars are basically like a giant

647
00:31:08,680 --> 00:31:12,520
Speaker 1: ball of soup of neutrons and quarks, right, So, I

648
00:31:12,520 --> 00:31:14,560
Speaker 1: mean it seems possible you could just scoop up some

649
00:31:14,880 --> 00:31:17,640
Speaker 1: neutrons or quarks and then damn you certainly get a

650
00:31:17,680 --> 00:31:18,840
Speaker 1: giant gold planet.

651
00:31:19,040 --> 00:31:21,200
Speaker 2: Well, neutron star is a little bit more complicated than that,

652
00:31:21,280 --> 00:31:23,520
Speaker 2: Like near the outside, they actually have a crust which

653
00:31:23,520 --> 00:31:25,920
Speaker 2: you can have some protons and electrons in it. Then

654
00:31:25,920 --> 00:31:28,480
Speaker 2: then we think there's probably a layer there's pure neutrons,

655
00:31:28,800 --> 00:31:31,560
Speaker 2: and below that we just don't really know, Like below

656
00:31:31,600 --> 00:31:34,000
Speaker 2: that probably doesn't even make sense to call it neutrons,

657
00:31:34,000 --> 00:31:35,880
Speaker 2: As you say, it's just like a soup of quarks,

658
00:31:36,000 --> 00:31:38,560
Speaker 2: like a quark gluon plasma, where the energy and the

659
00:31:38,600 --> 00:31:40,840
Speaker 2: density are so high that the whole idea of a

660
00:31:40,840 --> 00:31:43,360
Speaker 2: neutron doesn't really make sense. It's like a drop in

661
00:31:43,400 --> 00:31:46,000
Speaker 2: an ocean, right, you don't really call it a drop anymore.

662
00:31:46,200 --> 00:31:48,200
Speaker 2: And then below that we think probably there are new

663
00:31:48,280 --> 00:31:52,000
Speaker 2: states of matter, nuclear pasta or other weird exotic forms

664
00:31:52,000 --> 00:31:54,760
Speaker 2: of matter that only exist under these very high pressure

665
00:31:54,760 --> 00:31:57,800
Speaker 2: and temperature situations. So it's not just a ball of neutrons,

666
00:31:57,880 --> 00:31:59,680
Speaker 2: though there's plenty of neutrons there to play with.

667
00:32:00,040 --> 00:32:03,040
Speaker 1: H all right, So it sounds sort of unlikely that

668
00:32:03,080 --> 00:32:06,440
Speaker 1: in our universe there have foreign moons or big asteroids

669
00:32:06,480 --> 00:32:09,560
Speaker 1: of just pure gold. Right. Although there aren't there giant

670
00:32:09,560 --> 00:32:11,760
Speaker 1: asteroids of pure iron out there.

671
00:32:12,120 --> 00:32:14,960
Speaker 2: There are giant asteroids out there which are very metallic.

672
00:32:15,040 --> 00:32:17,280
Speaker 2: Like in our Solar system. We have a bunch of

673
00:32:17,360 --> 00:32:20,840
Speaker 2: different kinds of asteroids. There's like C type that have

674
00:32:20,920 --> 00:32:23,040
Speaker 2: a lot of water and ice in them, but there

675
00:32:23,080 --> 00:32:25,280
Speaker 2: is a kind called S type, which is a lot

676
00:32:25,320 --> 00:32:28,440
Speaker 2: of metal. For example, like a ten meters wide asteroid

677
00:32:28,720 --> 00:32:32,720
Speaker 2: might have like six hundred thousand kilograms of metal, including

678
00:32:33,200 --> 00:32:36,600
Speaker 2: like fifty kilograms of platinum and gold. And then there's

679
00:32:36,640 --> 00:32:39,440
Speaker 2: the M type, which are more rare, but they have

680
00:32:39,520 --> 00:32:42,680
Speaker 2: like ten times as much metal. So yes, these asteroids

681
00:32:42,760 --> 00:32:44,160
Speaker 2: do have a lot of metal in them, but they

682
00:32:44,200 --> 00:32:47,600
Speaker 2: start from the same basic materials as the Earth, and

683
00:32:47,640 --> 00:32:49,760
Speaker 2: so roughly they have like a random scoop of the

684
00:32:49,800 --> 00:32:52,240
Speaker 2: Solar system. It's just on the Earth, a lot of

685
00:32:52,240 --> 00:32:54,760
Speaker 2: this stuff is sunk down into the core and so

686
00:32:54,800 --> 00:32:56,760
Speaker 2: it's not as prevalent in the crust.

687
00:32:57,240 --> 00:32:59,720
Speaker 1: So you're saying that there are metal asteroids out there,

688
00:32:59,760 --> 00:33:01,560
Speaker 1: but there are sort of a mix of metals.

689
00:33:01,800 --> 00:33:04,880
Speaker 2: Yeah, exactly. It's not a pure gold asteroid, very unlikely,

690
00:33:05,160 --> 00:33:07,880
Speaker 2: or pure platinum. Most of these things are rocks with

691
00:33:08,000 --> 00:33:10,280
Speaker 2: a lot of metals mixed in and so, yes, they

692
00:33:10,320 --> 00:33:12,920
Speaker 2: are rich in gold and platinum. It's definitely out there.

693
00:33:13,320 --> 00:33:16,480
Speaker 2: But a pure gold asteroid or a silver asteroid, especially

694
00:33:16,480 --> 00:33:18,960
Speaker 2: when the size of the moon seems very unlikely.

695
00:33:19,480 --> 00:33:21,400
Speaker 1: What about gold plated, I mean it is, you know,

696
00:33:21,600 --> 00:33:23,240
Speaker 1: sometimes that's just as violable.

697
00:33:27,720 --> 00:33:29,680
Speaker 2: Well, you know, maybe we've been fooled and they actually

698
00:33:29,720 --> 00:33:31,040
Speaker 2: aren't filled with gold.

699
00:33:31,080 --> 00:33:34,680
Speaker 1: They just covered it's a pure gold inside. It's just

700
00:33:34,720 --> 00:33:36,280
Speaker 1: a mix of metals on the outside.

701
00:33:36,320 --> 00:33:38,000
Speaker 2: Well, you might wonder, like, how do we know the

702
00:33:38,000 --> 00:33:40,960
Speaker 2: composition of these things. It's mostly by looking at their

703
00:33:41,000 --> 00:33:44,400
Speaker 2: gravitational behavior. We can deduce their mass, and by looking

704
00:33:44,440 --> 00:33:46,560
Speaker 2: at their size, we deduce their volume, and that gives

705
00:33:46,640 --> 00:33:49,240
Speaker 2: us a sense of their density, and so we estimate

706
00:33:49,280 --> 00:33:51,760
Speaker 2: from the density of these things what they might be

707
00:33:51,840 --> 00:33:54,040
Speaker 2: made out of. For example, NASA is planning a mission

708
00:33:54,280 --> 00:33:57,440
Speaker 2: to an asteroid called Psyche, which is a big M

709
00:33:57,520 --> 00:34:01,360
Speaker 2: type asteroid. It's like two hundred kilometers across, and it's

710
00:34:01,400 --> 00:34:04,400
Speaker 2: so heavy, so dense that it has one percent of

711
00:34:04,400 --> 00:34:07,200
Speaker 2: the mass of the entire asteroid belt in this one

712
00:34:07,760 --> 00:34:10,480
Speaker 2: very metallic, very dense asteroid.

713
00:34:10,800 --> 00:34:14,760
Speaker 1: WHOA. Well, I wonder if maybe Mike was also asking

714
00:34:14,800 --> 00:34:17,520
Speaker 1: the question, like could you make a giant moon out

715
00:34:17,520 --> 00:34:19,160
Speaker 1: of gold? Like would it hold?

716
00:34:24,120 --> 00:34:26,040
Speaker 2: I don't think Mike was asking that. I think you're

717
00:34:26,040 --> 00:34:29,280
Speaker 2: asking that. I'm wondering what sort of like astro geoengineering

718
00:34:29,320 --> 00:34:31,400
Speaker 2: projects you have in mind over there.

719
00:34:31,920 --> 00:34:34,200
Speaker 1: Well, he's asking how large an object there or such

720
00:34:34,239 --> 00:34:35,279
Speaker 1: an object could there be?

721
00:34:35,560 --> 00:34:38,600
Speaker 2: Hmm, Yeah, that's a good question. In principle, you can

722
00:34:38,640 --> 00:34:41,520
Speaker 2: make an object about the size of the Earth, any

723
00:34:41,640 --> 00:34:45,560
Speaker 2: rocky object, anything primarily made out of heavier elements. You

724
00:34:45,560 --> 00:34:47,879
Speaker 2: can't really make it much bigger than the Earth because

725
00:34:47,880 --> 00:34:50,560
Speaker 2: then it's gravity just makes it denser and denser. You

726
00:34:50,560 --> 00:34:53,200
Speaker 2: can make about an earth sized blob of gold and

727
00:34:53,280 --> 00:34:55,280
Speaker 2: have it floating out there in the solar system.

728
00:34:55,400 --> 00:34:59,480
Speaker 1: Whoa, it's a lot of bling for the solar system.

729
00:35:01,239 --> 00:35:03,920
Speaker 2: That'd be a pretty cool engineering project. Like if you

730
00:35:03,960 --> 00:35:05,680
Speaker 2: come to an alien solar system and you find that

731
00:35:05,719 --> 00:35:09,480
Speaker 2: it's filled with like huge diamonds and Earth sized blobs

732
00:35:09,480 --> 00:35:11,520
Speaker 2: of gold. You might think like, Wow, these aliens know

733
00:35:11,560 --> 00:35:12,080
Speaker 2: what they're doing.

734
00:35:12,960 --> 00:35:16,080
Speaker 1: Or maybe gold is so cheap that they can make

735
00:35:16,120 --> 00:35:18,880
Speaker 1: a whole planet out of them.

736
00:35:18,880 --> 00:35:21,880
Speaker 2: Or maybe they've transcended the Kardashev scale and into the

737
00:35:21,960 --> 00:35:23,800
Speaker 2: Kardashian scale as you joked about it.

738
00:35:24,440 --> 00:35:28,120
Speaker 1: Yeah, there you go. All right, Well, thanks Mike for

739
00:35:28,160 --> 00:35:31,680
Speaker 1: that question. I guess the answer is that it's not likely,

740
00:35:32,160 --> 00:35:34,880
Speaker 1: but still possible. In the end, we don't really know.

741
00:35:36,400 --> 00:35:38,760
Speaker 2: In the end, almost anything is possible, but it seems

742
00:35:38,920 --> 00:35:41,960
Speaker 2: very unlikely for the universe to arrange for a gold

743
00:35:42,040 --> 00:35:43,160
Speaker 2: moon in our sky.

744
00:35:43,480 --> 00:35:46,280
Speaker 1: Unless Mike is secretly a super trillionaire or something.

745
00:35:47,280 --> 00:35:49,239
Speaker 2: If he finds that gold moon, he'll definitely be one.

746
00:35:49,800 --> 00:35:51,879
Speaker 1: Yeah. Other then you have to wonder why he lives

747
00:35:51,880 --> 00:35:52,480
Speaker 1: in New Jersey.

748
00:35:52,600 --> 00:35:54,600
Speaker 2: Oh he said, Brooklyn.

749
00:35:54,640 --> 00:35:57,560
Speaker 1: Oh, Brooklyn, Brooklyn. Oh, well that makes more sense. All right. Well,

750
00:35:57,640 --> 00:35:59,319
Speaker 1: let's get to our last question of the day, and

751
00:35:59,360 --> 00:36:03,640
Speaker 1: this one is the effects of gravitational waves on time.

752
00:36:04,320 --> 00:36:06,800
Speaker 1: So let's get to that. But first let's take another

753
00:36:06,880 --> 00:36:22,040
Speaker 1: quick break where we're asking listener questions here today, and

754
00:36:22,080 --> 00:36:24,879
Speaker 1: our third question comes from Max.

755
00:36:25,960 --> 00:36:30,600
Speaker 3: Hi, Daniel Dan JORGEV. This is Max calling from Stockholm, Sweden.

756
00:36:31,800 --> 00:36:37,480
Speaker 3: I have a question about gravitational waves, as they affect

757
00:36:37,840 --> 00:36:42,960
Speaker 3: the space, which has been proven in Bligo and Virgo,

758
00:36:43,640 --> 00:36:48,640
Speaker 3: do they also affect time the same way? Being compressed

759
00:36:49,160 --> 00:36:57,440
Speaker 3: and stressed as space, time is basically just one unit?

760
00:36:58,600 --> 00:37:02,520
Speaker 1: All right? Pretty cool? Can you get wavy with time?

761
00:37:02,680 --> 00:37:03,839
Speaker 1: Is basically the question.

762
00:37:04,640 --> 00:37:07,799
Speaker 2: Yeah. I love this kind of question because here again

763
00:37:07,800 --> 00:37:10,319
Speaker 2: he's bringing together two ideas we talk about all the time,

764
00:37:10,480 --> 00:37:13,719
Speaker 2: space and time are related. Gravitational waves or ripples in

765
00:37:13,800 --> 00:37:18,560
Speaker 2: space and time? Do they also affect time? Great question, Max.

766
00:37:18,719 --> 00:37:23,240
Speaker 1: Right, because I guess we know from relativity that gravity

767
00:37:23,320 --> 00:37:26,200
Speaker 1: is not just about making things come together. It's about

768
00:37:26,239 --> 00:37:29,200
Speaker 1: distorting space, and it's not just about distorting space but

769
00:37:29,200 --> 00:37:32,279
Speaker 1: also distorting time. Right, Like a black hole not just

770
00:37:32,360 --> 00:37:34,960
Speaker 1: bends space around it, but it also bends time around it.

771
00:37:35,040 --> 00:37:37,760
Speaker 2: Right. Yeah, that's exactly right. And there's a really important

772
00:37:37,800 --> 00:37:40,600
Speaker 2: progression of subtle ideas here as we go from like

773
00:37:41,160 --> 00:37:45,640
Speaker 2: Newton's idea of space and time to Einstein's special relativity

774
00:37:45,840 --> 00:37:47,799
Speaker 2: view of space and time where he brings space and

775
00:37:47,840 --> 00:37:51,600
Speaker 2: time together to one coherent object where they affect each other.

776
00:37:51,680 --> 00:37:54,200
Speaker 2: But we still have a clear sense of what time

777
00:37:54,320 --> 00:37:57,399
Speaker 2: is and what space is, and then into general relativity,

778
00:37:57,640 --> 00:37:59,719
Speaker 2: where concepts of space and time are much harder to

779
00:37:59,840 --> 00:38:02,719
Speaker 2: enter crprit out of our sort of generalized coordinates that

780
00:38:02,719 --> 00:38:03,319
Speaker 2: people use.

781
00:38:03,560 --> 00:38:07,040
Speaker 1: So maybe Tarrika for our listeners. What is a gravitational wave?

782
00:38:07,440 --> 00:38:11,520
Speaker 2: So gravitational wave is a wave in space time itself.

783
00:38:11,920 --> 00:38:14,799
Speaker 2: General relativity says we don't know what space time is,

784
00:38:15,320 --> 00:38:17,960
Speaker 2: but effectively, all we can do is measure the distances

785
00:38:18,000 --> 00:38:20,560
Speaker 2: between two points, Like we have this point here and

786
00:38:20,600 --> 00:38:22,960
Speaker 2: that point there. We can measure the distance between them,

787
00:38:23,280 --> 00:38:26,040
Speaker 2: and we can also measure the curvature of space, which

788
00:38:26,080 --> 00:38:29,560
Speaker 2: is how those relative distances change. So in space is curved,

789
00:38:29,840 --> 00:38:32,880
Speaker 2: things get closer together or further apart, depending on exactly

790
00:38:32,880 --> 00:38:35,879
Speaker 2: the nature of the curvature, and so ripples in that

791
00:38:35,960 --> 00:38:40,759
Speaker 2: curvature are gravitational waves because everything with energy creates curvature

792
00:38:41,120 --> 00:38:43,680
Speaker 2: in the universe. According to general relativity, if I have

793
00:38:43,719 --> 00:38:46,600
Speaker 2: a big massive object, then it's curving space and that's

794
00:38:46,640 --> 00:38:49,399
Speaker 2: what controls how things move around it. If I then

795
00:38:49,560 --> 00:38:53,280
Speaker 2: wiggle that object, then how I'm curving space is changing

796
00:38:53,320 --> 00:38:56,400
Speaker 2: with time because that information takes time to propagate out

797
00:38:56,600 --> 00:38:59,600
Speaker 2: from the wiggling object. So take a big black hole.

798
00:38:59,840 --> 00:39:03,200
Speaker 2: It's bending space. Now wiggle it, and you're making gravitational

799
00:39:03,280 --> 00:39:07,320
Speaker 2: waves from that black hole, waves in that curvature of space.

800
00:39:07,960 --> 00:39:11,000
Speaker 1: Right. It's kind of like about the propagation or how

801
00:39:11,040 --> 00:39:13,680
Speaker 1: it spreads the effects and how the group's effects of

802
00:39:13,719 --> 00:39:15,800
Speaker 1: gravity spread out basically.

803
00:39:15,440 --> 00:39:18,120
Speaker 2: Right, Yeah, if you wiggle a black hole, if the

804
00:39:18,160 --> 00:39:21,479
Speaker 2: curvature at a distant point doesn't instantly wiggle, right because

805
00:39:21,480 --> 00:39:23,600
Speaker 2: it doesn't know that you wiggle that, it takes time

806
00:39:23,920 --> 00:39:27,120
Speaker 2: for that information to propagate. And that's what the gravitational

807
00:39:27,160 --> 00:39:29,320
Speaker 2: wave is, is the propagation of that information.

808
00:39:29,760 --> 00:39:29,960
Speaker 4: Right.

809
00:39:30,040 --> 00:39:32,800
Speaker 1: Like, for example, if the Sun for some reason started

810
00:39:33,000 --> 00:39:36,359
Speaker 1: moving back and forth or wiggling or rocking back and forth, like,

811
00:39:36,440 --> 00:39:39,719
Speaker 1: we would feel that gravitational effect here on Earth, right,

812
00:39:39,719 --> 00:39:43,279
Speaker 1: we would feel that wiggling of the Sun gravitationally, like

813
00:39:43,320 --> 00:39:45,960
Speaker 1: the Earth would start to wobble too. But since it

814
00:39:46,000 --> 00:39:48,279
Speaker 1: takes some time for that gravitational effect to come from

815
00:39:48,360 --> 00:39:50,799
Speaker 1: the Sun to the Earth, that's kind of what we

816
00:39:50,840 --> 00:39:54,080
Speaker 1: call the wave, right, Like those wiggles as they propagate

817
00:39:54,080 --> 00:39:56,799
Speaker 1: out into the universe and then reach us, those are

818
00:39:56,880 --> 00:39:57,960
Speaker 1: the waves exactly.

819
00:39:58,000 --> 00:40:00,279
Speaker 2: It's very similar to other kinds of waves. You take

820
00:40:00,320 --> 00:40:03,920
Speaker 2: an electron has an electric field. Now you wiggle that electron,

821
00:40:04,200 --> 00:40:07,719
Speaker 2: you're making wiggles in that electric field. Those wiggles are photons.

822
00:40:08,000 --> 00:40:11,560
Speaker 2: Those ripples are updating you about where the electron is now.

823
00:40:12,040 --> 00:40:13,719
Speaker 2: So the same way you can create ripples in the

824
00:40:13,719 --> 00:40:17,360
Speaker 2: electromagnetic field by wiggling an electron, you can create ripples

825
00:40:17,360 --> 00:40:20,240
Speaker 2: in space time by wiggling anything that has mass.

826
00:40:20,560 --> 00:40:22,960
Speaker 1: All right, Now we've been able to measure those from

827
00:40:23,640 --> 00:40:26,640
Speaker 1: really incredible events that are happening out there in space.

828
00:40:26,920 --> 00:40:29,800
Speaker 2: Yeah, it's really sort of amazing. Einstein predicted these things,

829
00:40:30,080 --> 00:40:32,320
Speaker 2: but he also said we may never see them because

830
00:40:32,360 --> 00:40:36,560
Speaker 2: these are very very small. We're talking about tiny changes

831
00:40:36,600 --> 00:40:40,360
Speaker 2: in the distances between objects. Like you hold two mirrors

832
00:40:40,360 --> 00:40:43,600
Speaker 2: a couple of miles apart. The distance between them might

833
00:40:43,680 --> 00:40:46,600
Speaker 2: change by less than the width of a proton as

834
00:40:46,600 --> 00:40:49,759
Speaker 2: the gravitational wave passes by. So these things are very

835
00:40:49,800 --> 00:40:52,040
Speaker 2: difficult to measure. But we actually have been able to.

836
00:40:52,440 --> 00:40:56,160
Speaker 2: They have these very sensitive interferometers. We shoot laser beams

837
00:40:56,160 --> 00:40:59,120
Speaker 2: between these mirrors that are very carefully isolated from everything.

838
00:41:00,000 --> 00:41:02,920
Speaker 2: Credible triumph of experimental physics. And they've seen them a

839
00:41:02,960 --> 00:41:05,120
Speaker 2: few years ago, and now we've seen dozens and dozens

840
00:41:05,160 --> 00:41:06,120
Speaker 2: of these things.

841
00:41:06,040 --> 00:41:09,239
Speaker 1: Right, Well, as we've mentioned before, like everything moving, any

842
00:41:09,280 --> 00:41:12,080
Speaker 1: mass moving makes a gravitation wave. If I wave my arm,

843
00:41:12,360 --> 00:41:15,680
Speaker 1: I'm creating gravitational waves. They're just so small that nobody

844
00:41:15,680 --> 00:41:18,200
Speaker 1: can ever really feel them, although I have been working

845
00:41:18,200 --> 00:41:21,760
Speaker 1: out on my arm is pretty pretty massive lately.

846
00:41:23,040 --> 00:41:27,399
Speaker 2: Technically requires acceleration, not just motion. But yes, any accelerating

847
00:41:27,440 --> 00:41:29,800
Speaker 2: mass will create gravitational.

848
00:41:29,120 --> 00:41:31,160
Speaker 1: Waves, right right, Like if I wave my arm, right.

849
00:41:31,760 --> 00:41:33,840
Speaker 2: Yeah, if you move it back and forth, that's acceleration,

850
00:41:34,000 --> 00:41:36,760
Speaker 2: and that will create gravitational waves. Those are so tiny

851
00:41:36,800 --> 00:41:39,520
Speaker 2: we'll never see them. Gravitational waves we have been able

852
00:41:39,560 --> 00:41:43,520
Speaker 2: to see are from super incredibly massive objects black holes

853
00:41:43,560 --> 00:41:46,680
Speaker 2: or neutron stars swirling around each other as they collide.

854
00:41:47,360 --> 00:41:49,719
Speaker 1: Now, does it have to be acceleration, Like if let's

855
00:41:49,760 --> 00:41:52,840
Speaker 1: say an asteroid is moving in a straight line through space,

856
00:41:53,440 --> 00:41:55,960
Speaker 1: doesn't it create a ripple as it goes along too?

857
00:41:56,160 --> 00:41:59,799
Speaker 1: Because I like, I'm going to feel differently it's gravitation

858
00:42:00,440 --> 00:42:02,560
Speaker 1: attraction as it goes past me.

859
00:42:02,920 --> 00:42:06,640
Speaker 2: Well, velocity is relative, right, and so the gravitational field

860
00:42:06,640 --> 00:42:09,480
Speaker 2: there doesn't depend on relative quantities. It only depends on

861
00:42:09,520 --> 00:42:14,240
Speaker 2: absolute quantities. Acceleration is absolute, and so you don't create

862
00:42:14,320 --> 00:42:19,200
Speaker 2: gravitational waves. Just by having a velocity. You can experience

863
00:42:19,200 --> 00:42:23,080
Speaker 2: a changing gravitational field, but that's not necessarily a gravitational wave.

864
00:42:23,239 --> 00:42:25,759
Speaker 2: Like if you're near the Earth and you're moving away

865
00:42:25,800 --> 00:42:27,640
Speaker 2: from the Earth, you're measuring a change in your local

866
00:42:27,719 --> 00:42:30,239
Speaker 2: gravity because you're moving away from the Earth. So time

867
00:42:30,280 --> 00:42:34,040
Speaker 2: dependence in your position and in your velocity. But there's

868
00:42:34,040 --> 00:42:37,400
Speaker 2: no gravitational wave created unless you have acceleration, which is

869
00:42:37,400 --> 00:42:38,400
Speaker 2: an absolute quantity.

870
00:42:38,600 --> 00:42:40,440
Speaker 1: It's sort of a wave, right, Like if an asteroid

871
00:42:40,480 --> 00:42:42,799
Speaker 1: flies past me, I'm going to feel no gravity from it,

872
00:42:43,040 --> 00:42:44,480
Speaker 1: and then I'm going to feel a lot of gravity

873
00:42:44,480 --> 00:42:46,319
Speaker 1: as it's near me, and then I'm going to feel

874
00:42:46,360 --> 00:42:48,759
Speaker 1: les gravity as it flies away from me. Then I

875
00:42:48,960 --> 00:42:51,320
Speaker 1: sort of experience kind of a wave of gravity.

876
00:42:51,680 --> 00:42:54,000
Speaker 2: Well, again, you experience a change in how much local

877
00:42:54,000 --> 00:42:56,880
Speaker 2: gravity you measure, Like if you get closer to an electron,

878
00:42:57,040 --> 00:42:59,040
Speaker 2: you're going to measure a stronger electric field, and if

879
00:42:59,040 --> 00:43:01,480
Speaker 2: you move away, you're gonna measure a weaker electric field.

880
00:43:01,600 --> 00:43:04,439
Speaker 2: But there's no electromagnetic wave there. It's just your motion

881
00:43:04,560 --> 00:43:07,440
Speaker 2: relative to the electron that's changing your local measurement.

882
00:43:08,960 --> 00:43:12,040
Speaker 1: The effect is the same, though, don't I feel changing

883
00:43:12,120 --> 00:43:15,120
Speaker 1: my gravitational field over time?

884
00:43:15,320 --> 00:43:17,520
Speaker 2: If you wanted to create exactly the same set of

885
00:43:17,560 --> 00:43:20,920
Speaker 2: local measurements, you wanted an oscillating gravitational field that you

886
00:43:20,960 --> 00:43:23,640
Speaker 2: need to move back and forth, and that's acceleration. So

887
00:43:24,160 --> 00:43:25,600
Speaker 2: you can't do it without acceleration.

888
00:43:25,920 --> 00:43:30,279
Speaker 1: M Well, let's get to the question here. Now, we

889
00:43:30,360 --> 00:43:34,000
Speaker 1: know that a gravitational wave affects space. That's how we

890
00:43:34,040 --> 00:43:36,520
Speaker 1: measure them, right, Like we have giant rulers made out

891
00:43:36,520 --> 00:43:40,759
Speaker 1: of lasers very deep underground, and as they contract and

892
00:43:40,880 --> 00:43:44,480
Speaker 1: expand we know that a gravitational wave has passed by us.

893
00:43:44,840 --> 00:43:45,040
Speaker 2: Yeah.

894
00:43:45,280 --> 00:43:47,400
Speaker 1: Now the question is does it also affect time?

895
00:43:47,880 --> 00:43:52,120
Speaker 2: Yeah? And the answer is pretty unsatisfying. The answer is

896
00:43:52,400 --> 00:43:55,600
Speaker 2: you can't really say yes or no because it depends

897
00:43:55,600 --> 00:43:58,600
Speaker 2: on what time means in general relativity, which is very

898
00:43:58,600 --> 00:44:02,880
Speaker 2: fuzzy and unclear. That's the short version of the unsatisfying answer.

899
00:44:03,520 --> 00:44:06,600
Speaker 2: The longer version of the unsatisfying answer. It takes a

900
00:44:06,640 --> 00:44:10,120
Speaker 2: bit of a tour through special relativity. Right, Like Newton says,

901
00:44:10,239 --> 00:44:13,000
Speaker 2: space and time are totally separate things. Things move through

902
00:44:13,040 --> 00:44:17,920
Speaker 2: space there obviously, time moves forward. Space and time are unrelated,

903
00:44:18,280 --> 00:44:21,239
Speaker 2: Einstein tells us in special relativity, No, no, space and

904
00:44:21,280 --> 00:44:23,920
Speaker 2: time are two parts of the same thing. It's a

905
00:44:23,920 --> 00:44:27,120
Speaker 2: beautiful realization that together they make a lot more sense

906
00:44:27,160 --> 00:44:30,360
Speaker 2: than a part. It's like electricity and magnetism fused together

907
00:44:30,520 --> 00:44:34,040
Speaker 2: into one idea makes much more sense than two separate ideas.

908
00:44:34,200 --> 00:44:35,879
Speaker 2: This is not to say that they're the same thing.

909
00:44:36,239 --> 00:44:38,480
Speaker 2: Two things can be two parts of the same thing

910
00:44:38,760 --> 00:44:41,400
Speaker 2: without being equivalent. Like you say the front and the

911
00:44:41,440 --> 00:44:43,560
Speaker 2: back of the elephant are two parts of an elephant.

912
00:44:43,600 --> 00:44:45,399
Speaker 2: Doesn't mean the front and back are the same thing.

913
00:44:45,960 --> 00:44:48,920
Speaker 2: So space and time are closely related in special relativity,

914
00:44:49,320 --> 00:44:51,799
Speaker 2: and space affects time and time effects space. But you

915
00:44:51,800 --> 00:44:54,920
Speaker 2: can always still say what is time and what is space?

916
00:44:55,719 --> 00:44:58,799
Speaker 2: Now we get to general relativity. In general relativity, the

917
00:44:58,840 --> 00:45:02,160
Speaker 2: coordinates you choose, like which direction things we're moving in,

918
00:45:02,280 --> 00:45:05,400
Speaker 2: are not so physical. They're just sort of like abstract,

919
00:45:05,880 --> 00:45:08,400
Speaker 2: and you can choose lots of different sort of systems

920
00:45:08,440 --> 00:45:11,680
Speaker 2: in order to do your calculations, like are using polar

921
00:45:11,719 --> 00:45:15,640
Speaker 2: coordinates or using xyz or lots of much more complicated

922
00:45:15,680 --> 00:45:19,960
Speaker 2: abstract coordinate systems, And some of those coordinates it's impossible

923
00:45:20,000 --> 00:45:22,520
Speaker 2: to say, like which direction is time and which direction

924
00:45:22,600 --> 00:45:25,560
Speaker 2: is space, they're all sort of mixed together. For example,

925
00:45:25,600 --> 00:45:28,040
Speaker 2: as you were saying earlier, what happens as you're going

926
00:45:28,040 --> 00:45:31,200
Speaker 2: inside a black hole, Well, time and space sort of reverse.

927
00:45:31,400 --> 00:45:35,600
Speaker 2: Right now, your future is the singularity. Every path into

928
00:45:35,640 --> 00:45:38,520
Speaker 2: your future ends at the singularity. Time and space have

929
00:45:38,640 --> 00:45:41,680
Speaker 2: sort of reversed roles there. That's just sort of shorthand

930
00:45:41,680 --> 00:45:44,160
Speaker 2: way of saying that we have a new interpretation for

931
00:45:44,200 --> 00:45:44,960
Speaker 2: the coordinates.

932
00:45:45,160 --> 00:45:48,319
Speaker 1: Now I imagine this is super complicated, but I feel

933
00:45:48,320 --> 00:45:50,600
Speaker 1: like we're getting a little bit abstract here. Like I

934
00:45:50,640 --> 00:45:54,000
Speaker 1: wonder if Max is asking, you know, how in these

935
00:45:54,280 --> 00:45:56,560
Speaker 1: experiments where we can measure gravitation of ways, you can

936
00:45:56,600 --> 00:46:00,959
Speaker 1: see that the length of something changes as the wave

937
00:46:01,000 --> 00:46:03,719
Speaker 1: goes past. Does I wonder if he's asking, you know,

938
00:46:03,760 --> 00:46:05,960
Speaker 1: if I had a clog, would I see my clock

939
00:46:06,040 --> 00:46:08,479
Speaker 1: suddenly take a little faster and then take a little

940
00:46:08,480 --> 00:46:10,000
Speaker 1: slower as the wave goes past me.

941
00:46:10,320 --> 00:46:12,319
Speaker 2: The answer is, you can't really separate it out into

942
00:46:12,320 --> 00:46:14,799
Speaker 2: the effects of space and the effects of time, and

943
00:46:14,840 --> 00:46:17,200
Speaker 2: the details of it dependent a little bit on exactly

944
00:46:17,239 --> 00:46:20,759
Speaker 2: how you've built your clock. Like let's say, instead of

945
00:46:20,800 --> 00:46:23,160
Speaker 2: having lego or you have lasers, and you're shooting lasers

946
00:46:23,200 --> 00:46:25,719
Speaker 2: back and forth to measure distance. You have like two

947
00:46:25,760 --> 00:46:28,480
Speaker 2: people far apart from each other, and they're constantly sending

948
00:46:28,520 --> 00:46:31,080
Speaker 2: each other little laser pings. Right like, I'm going to

949
00:46:31,160 --> 00:46:34,880
Speaker 2: send you a pulse of lasers every one nanosecond or something,

950
00:46:35,280 --> 00:46:37,239
Speaker 2: and then you're going to observe those We're going to

951
00:46:37,360 --> 00:46:39,720
Speaker 2: try to see if the time between the pulses changes

952
00:46:39,760 --> 00:46:42,600
Speaker 2: as the gravitational wave goes by. Right, Well, what's going

953
00:46:42,640 --> 00:46:45,080
Speaker 2: to happen as the gravitational wave goes by is that

954
00:46:45,120 --> 00:46:47,319
Speaker 2: those pings are going to get either red shifted or

955
00:46:47,360 --> 00:46:51,120
Speaker 2: blue shifted by the gravitational wave. But whether you interpret

956
00:46:51,200 --> 00:46:55,320
Speaker 2: that as like space expanding or time slowing down depends

957
00:46:55,480 --> 00:46:58,920
Speaker 2: in general relativity, on these coordinate systems that you've chosen.

958
00:46:59,239 --> 00:47:02,040
Speaker 2: So somebody could come along and say, look, I interpret

959
00:47:02,080 --> 00:47:04,440
Speaker 2: this as space bending. Somebody else come along and say, no,

960
00:47:04,480 --> 00:47:07,920
Speaker 2: I interpret that as time bending. In general relativity, most

961
00:47:07,960 --> 00:47:10,800
Speaker 2: people tend to work in what's called a synchronous gauge,

962
00:47:11,040 --> 00:47:13,480
Speaker 2: where you basically put all the bending into the space

963
00:47:13,520 --> 00:47:16,600
Speaker 2: part and you say time doesn't bend at all, And

964
00:47:16,640 --> 00:47:19,040
Speaker 2: that's just sort of like our interpretation. But it's totally

965
00:47:19,120 --> 00:47:21,880
Speaker 2: valid to say no, actually, time is doing the bending.

966
00:47:22,280 --> 00:47:24,399
Speaker 2: So the answer is sort of like, yeah, space time

967
00:47:24,440 --> 00:47:27,520
Speaker 2: as a whole is bending. Whether you call that space

968
00:47:27,560 --> 00:47:29,799
Speaker 2: bending or time bending is a little bit arbitrary.

969
00:47:30,400 --> 00:47:32,279
Speaker 1: I wonder if what do you mean is like, let's

970
00:47:32,280 --> 00:47:36,319
Speaker 1: say a measuring time using a Grandfather clock, right with

971
00:47:36,520 --> 00:47:41,000
Speaker 1: like a swinging pendulum, and that's how measuring time. Now,

972
00:47:41,040 --> 00:47:46,640
Speaker 1: if the wave is coming let's say from directly at me,

973
00:47:47,800 --> 00:47:51,640
Speaker 1: and I face the Grandfather clock in one direction, then

974
00:47:52,920 --> 00:47:54,719
Speaker 1: maybe it's not going to fec how it takes. But

975
00:47:54,760 --> 00:47:56,759
Speaker 1: if I turn in ninety degrees, maybe it is going

976
00:47:56,800 --> 00:47:58,960
Speaker 1: to efac how it takes. And in which case you

977
00:47:59,040 --> 00:48:03,040
Speaker 1: might say in one instance that it did slow down time,

978
00:48:03,320 --> 00:48:04,880
Speaker 1: But in the other instance you might say, no, it

979
00:48:04,880 --> 00:48:08,240
Speaker 1: doesn't slow that time. It just stretched space.

980
00:48:08,840 --> 00:48:10,640
Speaker 2: Yeah, that's right. And even in the case where it

981
00:48:10,640 --> 00:48:13,080
Speaker 2: did slow down time, you could argue it did it

982
00:48:13,160 --> 00:48:15,959
Speaker 2: slow down time because time actually went slower or because

983
00:48:16,040 --> 00:48:18,839
Speaker 2: increase the distance that the pendulum had to swing, Right,

984
00:48:18,880 --> 00:48:21,560
Speaker 2: You can interpret it both ways. Sort of how even

985
00:48:21,560 --> 00:48:25,440
Speaker 2: in special relativity you can interpret like contraction of distances

986
00:48:25,640 --> 00:48:28,400
Speaker 2: and stretching of time to be two sides of the

987
00:48:28,400 --> 00:48:31,160
Speaker 2: same coin, Like when I travel to a nearby star

988
00:48:31,239 --> 00:48:34,080
Speaker 2: at nearer the speed of light, I see the distance

989
00:48:34,080 --> 00:48:36,319
Speaker 2: to the star contracted, so it only takes me a

990
00:48:36,360 --> 00:48:39,200
Speaker 2: minute to get there. Somebody else sees me flying for

991
00:48:39,400 --> 00:48:41,400
Speaker 2: light years, but my time is slowed down, which is

992
00:48:41,400 --> 00:48:43,839
Speaker 2: why it only seems like a minute for me. So

993
00:48:43,960 --> 00:48:47,480
Speaker 2: I see length contracted, somebody else sees time dilated. In

994
00:48:47,520 --> 00:48:50,200
Speaker 2: many cases, it just depends on your perspective whether you're

995
00:48:50,239 --> 00:48:52,400
Speaker 2: calling it a space effect or a time effect.

996
00:48:53,560 --> 00:48:57,440
Speaker 1: Well as it is super complicated. But I feel like

997
00:48:57,440 --> 00:48:59,880
Speaker 1: maybe in the past we've talked about or you've mentioned

998
00:49:00,200 --> 00:49:02,800
Speaker 1: there are separate effects in terms of the bending of

999
00:49:02,880 --> 00:49:05,840
Speaker 1: space and the slowing down of time, Like if you

1000
00:49:05,920 --> 00:49:09,280
Speaker 1: swing by a black hole, then time will move slower

1001
00:49:09,320 --> 00:49:12,200
Speaker 1: for you. Right, that's not up for interpretation, is it.

1002
00:49:12,520 --> 00:49:14,960
Speaker 2: You're exactly right that there are two separate effects we're

1003
00:49:14,960 --> 00:49:18,160
Speaker 2: talking about here. One is like velocity dependent time dilation

1004
00:49:18,320 --> 00:49:22,400
Speaker 2: or length contraction, which is a different effect than gravitational

1005
00:49:22,480 --> 00:49:25,440
Speaker 2: based time dilation, which is just due to the curvature

1006
00:49:25,480 --> 00:49:28,120
Speaker 2: of space. You're totally right, those are two separate effects,

1007
00:49:28,600 --> 00:49:31,960
Speaker 2: and you're right that the gravitational one is an absolute effect.

1008
00:49:32,000 --> 00:49:34,200
Speaker 2: It's not like I see your time slowed down and

1009
00:49:34,200 --> 00:49:36,719
Speaker 2: you see my time slowed down and the gravitational one.

1010
00:49:36,760 --> 00:49:39,279
Speaker 2: Everybody agrees, like the person close to the black hole

1011
00:49:39,360 --> 00:49:42,120
Speaker 2: agrees that their time is going slower than the person

1012
00:49:42,200 --> 00:49:43,239
Speaker 2: further from the black hole.

1013
00:49:43,360 --> 00:49:46,319
Speaker 1: So then what's happening as a gravitational wave goes past me?

1014
00:49:46,480 --> 00:49:48,960
Speaker 1: Is it more like a black hole, like we're getting

1015
00:49:48,960 --> 00:49:51,759
Speaker 1: far from a black hole, or is it more like

1016
00:49:51,800 --> 00:49:53,080
Speaker 1: we're speeding up and slowing that.

1017
00:49:53,520 --> 00:49:55,840
Speaker 2: The gravitational wave is a curvature effects, so it's definitely

1018
00:49:55,840 --> 00:49:58,120
Speaker 2: more like being close to a black hole. But I

1019
00:49:58,160 --> 00:50:00,520
Speaker 2: was going to say that even the story with being

1020
00:50:00,560 --> 00:50:02,880
Speaker 2: close to a black hole, we're interpreting that as an

1021
00:50:02,920 --> 00:50:05,880
Speaker 2: effect on time. You can also change your gauge. They

1022
00:50:05,920 --> 00:50:09,200
Speaker 2: call it in general relativity, redefine the axes and pretend

1023
00:50:09,239 --> 00:50:12,360
Speaker 2: that it's only happening in space coordinates. So in general

1024
00:50:12,400 --> 00:50:15,520
Speaker 2: relativity you can basically interpret these things as space or time,

1025
00:50:16,040 --> 00:50:19,440
Speaker 2: because the distinction between the two becomes much more fuzzy.

1026
00:50:19,480 --> 00:50:21,880
Speaker 1: Even the case of going near a black hole. I me,

1027
00:50:21,920 --> 00:50:24,440
Speaker 1: you just say that everyone can agree that time slow.

1028
00:50:24,280 --> 00:50:26,920
Speaker 2: Down, everyone agrees about the magnitude of the effect, and

1029
00:50:27,000 --> 00:50:29,399
Speaker 2: if both of you agree on the co ordinates, then

1030
00:50:29,400 --> 00:50:32,320
Speaker 2: we interpret that in terms of time. So, yeah, everybody

1031
00:50:32,320 --> 00:50:34,319
Speaker 2: agrees that the person close to the black hole has

1032
00:50:34,360 --> 00:50:37,719
Speaker 2: a stronger effect. If you're using a certain gauge, then

1033
00:50:37,760 --> 00:50:40,200
Speaker 2: we interpret that as a time effect. If we choose

1034
00:50:40,200 --> 00:50:43,000
Speaker 2: a different gauge, then we interpret that as a space effect.

1035
00:50:43,480 --> 00:50:46,160
Speaker 2: The thing we agree on is the magnitude of the effect.

1036
00:50:46,280 --> 00:50:48,920
Speaker 2: Whether it's space or time is up to interpretation.

1037
00:50:49,520 --> 00:50:51,719
Speaker 1: Wait, so then you already saying that when I go

1038
00:50:51,840 --> 00:50:54,239
Speaker 1: near a black hole, I could interpret that not as

1039
00:50:54,280 --> 00:50:55,240
Speaker 1: a change in time.

1040
00:50:55,600 --> 00:50:58,360
Speaker 2: Yes, you could choose some weird coordinates in general relativity

1041
00:50:58,360 --> 00:51:00,880
Speaker 2: to interpret that as just a bend of space, because

1042
00:51:00,880 --> 00:51:03,480
Speaker 2: it is a bending of space, right, that's curvature, And

1043
00:51:03,520 --> 00:51:05,840
Speaker 2: so if you redefine your time, then you could choose

1044
00:51:05,880 --> 00:51:07,080
Speaker 2: time to be invariant.

1045
00:51:07,160 --> 00:51:09,279
Speaker 1: Yeah, but it isn't the case. I mean, I know

1046
00:51:09,320 --> 00:51:11,640
Speaker 1: this because I saw the movie Interstellar that if you

1047
00:51:11,760 --> 00:51:14,040
Speaker 1: go near a black hole and then come back, you'll

1048
00:51:14,080 --> 00:51:17,520
Speaker 1: be younger than me. That's not That doesn't seem like

1049
00:51:17,600 --> 00:51:20,600
Speaker 1: it depends on a coordinate system. That's like, I'm gonna

1050
00:51:20,600 --> 00:51:22,759
Speaker 1: see you're you're gonna be younger than me. There's no

1051
00:51:22,800 --> 00:51:24,000
Speaker 1: way that I cannot see that.

1052
00:51:24,120 --> 00:51:25,839
Speaker 2: If one of us takes a trip to the black

1053
00:51:25,880 --> 00:51:29,080
Speaker 2: hole and comes back, then you completed a loop. You're

1054
00:51:29,080 --> 00:51:32,280
Speaker 2: back to the same location in space, and that makes

1055
00:51:32,320 --> 00:51:35,640
Speaker 2: those calculations invariant. It actually doesn't depend in that case

1056
00:51:36,040 --> 00:51:38,920
Speaker 2: on the choice of coordinates or gauges. So yeah, in

1057
00:51:38,960 --> 00:51:42,000
Speaker 2: that case, like in Interstellar, everyone also agrees.

1058
00:51:42,320 --> 00:51:46,440
Speaker 1: All right, well, then let's mee just close it out then,

1059
00:51:46,520 --> 00:51:49,560
Speaker 1: and what would say is the answer then? For Max's question,

1060
00:51:49,920 --> 00:51:52,919
Speaker 1: does time get dilated as a gravitation away comes through

1061
00:51:53,640 --> 00:51:54,920
Speaker 1: or can you just ignore it?

1062
00:51:55,000 --> 00:51:58,239
Speaker 2: I would say that space time does get dilated absolutely,

1063
00:51:58,680 --> 00:52:01,759
Speaker 2: which part of space time? Saying gets stretched out is

1064
00:52:01,800 --> 00:52:04,799
Speaker 2: a little bit arbitrary. Most people tend to work in

1065
00:52:04,880 --> 00:52:08,200
Speaker 2: a choice of gauges where only space is getting stretched.

1066
00:52:08,320 --> 00:52:10,560
Speaker 2: It's just sort of simpler, and it's more natural for

1067
00:52:10,600 --> 00:52:12,440
Speaker 2: people to choose. But in the end it is a

1068
00:52:12,440 --> 00:52:15,040
Speaker 2: little arbitrary because it really is all of space time

1069
00:52:15,160 --> 00:52:16,040
Speaker 2: getting squeezed.

1070
00:52:16,520 --> 00:52:18,920
Speaker 1: All right, And if Matthew McConaughey were to serve a

1071
00:52:18,960 --> 00:52:23,000
Speaker 1: gravitational wave, would he look come back younger or older?

1072
00:52:23,800 --> 00:52:25,319
Speaker 1: Let he makes it too sure.

1073
00:52:25,480 --> 00:52:27,480
Speaker 2: I think he's frozen in time. He doesn't look like

1074
00:52:27,480 --> 00:52:28,319
Speaker 2: he's aging at all.

1075
00:52:28,560 --> 00:52:30,400
Speaker 1: Right, right, that's what I mean that maybe that's a

1076
00:52:30,440 --> 00:52:32,919
Speaker 1: secret he's serving gravitational waves up there.

1077
00:52:33,760 --> 00:52:35,920
Speaker 2: Yeah, we should all be in the Matthew McConaughey gauge.

1078
00:52:35,960 --> 00:52:38,520
Speaker 1: There you go, and then maybe we can all retire.

1079
00:52:40,160 --> 00:52:43,200
Speaker 1: All right. Well, we tried, Max, Sorry, but it sounds

1080
00:52:43,239 --> 00:52:46,080
Speaker 1: like the answer is that it's really complicated and you

1081
00:52:46,120 --> 00:52:49,719
Speaker 1: need a degree in gravitational relativity to figure it out.

1082
00:52:51,480 --> 00:52:54,520
Speaker 2: But you're right that space and time are deeply, deeply connected.

1083
00:52:54,600 --> 00:52:56,799
Speaker 1: All right. Well, thanks to everyone who sent them their

1084
00:52:57,000 --> 00:53:00,239
Speaker 1: questions here today. It's always fun to take a deep

1085
00:53:00,360 --> 00:53:04,000
Speaker 1: dive into people's curiosity and to think about these scenarios

1086
00:53:04,040 --> 00:53:06,759
Speaker 1: that we don't think about it every day.

1087
00:53:07,200 --> 00:53:10,640
Speaker 2: Absolutely, we love your curiosity, not just because it tells

1088
00:53:10,719 --> 00:53:13,360
Speaker 2: us that our passion for wanting to understand the universe

1089
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Speaker 2: is shared by so many other people, but because it

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Speaker 2: actually literally powers us. Your support for science and your

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00:53:19,880 --> 00:53:23,520
Speaker 2: curiosity is what makes science possible. Thank you very much.

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Speaker 1: Yeah, and if anyone ever makes a gold asteroid out there, hey,

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Speaker 1: how about you sent me a chunk of it, because

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00:53:29,640 --> 00:53:32,280
Speaker 1: you know more about forty two years late on retiring.

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00:53:32,640 --> 00:53:35,239
Speaker 2: Yeah, so please donate a chunk of your next gold

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00:53:35,280 --> 00:53:36,680
Speaker 2: asteroid to Jorge's retirement.

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Speaker 1: Yeah, there you go. All right, Well, we hope you

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Speaker 1: enjoyed that. Thanks for joining us, See you next time.

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Speaker 2: For more science and curiosity, come find us on social media,

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00:53:51,120 --> 00:53:55,720
Speaker 2: where we answer questions and post videos. We're on Twitter, disporg, Instant,

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00:53:55,760 --> 00:53:59,440
Speaker 2: and now TikTok. Thanks for listening, and remember that Daniel

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Speaker 2: and Jorge Explain the Universe is a production of iHeartRadio.

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Speaker 2: For more podcasts from iHeartRadio, visit the iHeartRadio app, Apple Podcasts,

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00:54:08,480 --> 00:54:10,840
Speaker 2: or wherever you listen to your favorite shows.