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Speaker 1: Any Daniel, do you think kids think about the world differently? Oh,

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Speaker 1: I'm sure they do because they aren't tied down by

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Speaker 1: all of our crazy misconceptions. Actually, I meant because they

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Speaker 1: have smaller brains. But I think you're right about the misconceptions.

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Speaker 1: Do you think that makes them smarter than us? I

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Speaker 1: don't know, but I think there's a reason that it's

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Speaker 1: rare to have, like a brilliant insight or crazy new

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Speaker 1: idea after your thirty Mm. So just because I'm older

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Speaker 1: than thirty, that means I'm never gonna win the Nobel

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Speaker 1: Prize in physics. Oh no, No, you might still, but

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Speaker 1: it would be for an idea you had when you

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Speaker 1: were twenty nine. You mean, like when I decided to

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Speaker 1: leave academia and become a cartoonist. Yeah, maybe the best

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Speaker 1: idea you ever had. Do they give Nobel prices in

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Speaker 1: bad career choices? Hi? I am more handmade cartoonist and

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Speaker 1: the creator of PhD comics. Hi, I'm Daniel. I'm a

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Speaker 1: particle physicist and a professor UC Irvine. And I was

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Speaker 1: once stumped by a question from a six year old. Really,

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Speaker 1: was it a question about physics or just about life?

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Speaker 1: It sort of was. I was doing demonstrations and the

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Speaker 1: elementary school about how cool liquid nitrogen is, and some

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Speaker 1: kid asked me if lightsabers were real, would they be

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Speaker 1: made of liquid nitrogen? Interesting question. It's like it's blending

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Speaker 1: fiction and reality and some imagination there. Yeah. I was

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Speaker 1: literally stumped. I had no idea how to that question

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Speaker 1: in the universe in which lightsabers like, is a khyber

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Speaker 1: crystal made out of liquid nitrogen? Really? It could be, right, Yeah,

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Speaker 1: I suppose it could. Can you make a crystal out

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Speaker 1: of liquid nitrogen? Somehow? I guess that would be crystal nitrogen? Yeah.

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Speaker 1: But welcome to our podcast Annual and Jorge Explain the Universe,

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Speaker 1: a production of I Heart Radio in which we try

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Speaker 1: to summon that curiosity we all had when we were

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Speaker 1: children about the way the world worked and extend that

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Speaker 1: to everything in the universe and wonder about the nature

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Speaker 1: of the universe, the origin of the universe, explanations for

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Speaker 1: how everything works, and dig into the mysteries for the

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Speaker 1: things that we still don't understand. We apply our innate

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Speaker 1: curiosity to everything in the universe because we think that

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Speaker 1: everything is understandable and that if we bang away at

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Speaker 1: it long enough, we eventually we will figure things out. Yeah,

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Speaker 1: because it is a big universe and there are enough

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Speaker 1: questions in it for all kinds of people are young

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Speaker 1: and old. He might be eight years old and still

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Speaker 1: have questions about the universe, or he might be ninety

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Speaker 1: nine and also have questions about the university. Universe seems

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Speaker 1: to never run out of questions. That's right, And some

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Speaker 1: of the questions that we are asking suggests that, like

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Speaker 1: we as a species are quite young. End of the way,

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Speaker 1: the kids ask very basic questions, you know, like where

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Speaker 1: does the sun go at night? Stuff like that. We

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Speaker 1: are still asking really basic questions. How old is the universe,

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Speaker 1: what happened before it? How big is it? What's past?

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Speaker 1: What we can see? Really, just like novice initial questions

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Speaker 1: do you ask as a species coming into these universe

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Speaker 1: and wondering about our place in it? Are you saying

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Speaker 1: our species is like in the teenage years you think

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Speaker 1: or are we tweens? No? I think we're basically six

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Speaker 1: year old intellectually as a species. I think we're six

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Speaker 1: years old. We're asking really basic questions. We're still in

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Speaker 1: the kindergarten of the galaxy exactly. We're asking questions that

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Speaker 1: reveal the way we think about the universe rather than

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Speaker 1: the way the universe works. You know, we're asking the

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Speaker 1: questions we think are important and that reveal our misunderstandings

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Speaker 1: about how the universe works. Well, we definitely don't have

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Speaker 1: our wisdom teeth yet. As a species, we're definitely lacking

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Speaker 1: any wisdom, it seems these days. But there is a

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Speaker 1: lot of that you can ask about the universe, and

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Speaker 1: it's for all kinds of ages. Yeah, and sometimes it's

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Speaker 1: fun to dig back into that. You know, as a researcher,

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Speaker 1: I'm working at like the very edge of knowledge, asking

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Speaker 1: very pacific questions what's inside a cork? Or are electrons

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Speaker 1: made of something smaller? But it's fun to go back

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Speaker 1: to the questions at five year old, six year old,

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Speaker 1: ten year olds ask and remember that we still don't

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Speaker 1: have answers to those big questions. And like, the whole

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Speaker 1: context of our exploration is that we're trying to answer

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Speaker 1: these really big, basic, deep questions, and that all the

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Speaker 1: specific work we're doing at the edge of knowledge and

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Speaker 1: the end is motivated by trying to get back to

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Speaker 1: those basic questions. I think trying to make a lightsaber

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Speaker 1: is at the edge of knowledge, thank you. I mean,

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Speaker 1: have you seen those YouTube videos where people try to

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Speaker 1: recreate lightsabers? It's hard, it's really impossible almost what motivated

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Speaker 1: you to walk to those who Hey, when you're trying

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Speaker 1: to build one yourself. I was curious as a kid, Yes,

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Speaker 1: to watch YouTube videos. You're gonna slice your way out

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Speaker 1: of your childhood situation. No, I've not gone down that

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Speaker 1: particular rabbit hole. But yeah, there's a lot of really

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Speaker 1: fun questions we asked there. Yeah, and sometimes we get

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Speaker 1: those questions here and our inbox, and specifically we get

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Speaker 1: questions from little kids, not just adults or young people

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Speaker 1: like like the people listening to this podcast right now,

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Speaker 1: But we got questions from a little little kids, that's right.

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Speaker 1: Sometimes folks have their seven year old or their ten

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Speaker 1: year olds listening with them and a podcast will inspire

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Speaker 1: a question, and then they'll write to us and say, Hey,

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Speaker 1: my kid asked me this question. I don't know the answer.

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Speaker 1: Maybe you guys can help out, which makes me glad

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Speaker 1: about all the jokes we don't say in this podcast,

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Speaker 1: all those jokes about dark matter, and that's right, all

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Speaker 1: those racy browser histories that we don't like to talk

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Speaker 1: about but exactly because we hope that you are out

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Speaker 1: there listening with your kids and that inspires conversations. I'm

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Speaker 1: always really happy to hear when somebody writes it and says,

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Speaker 1: how was listening to your podcast with my eleven year

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Speaker 1: old and then we spent an hour talking about what's

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Speaker 1: inside a black hole or just on the way to school,

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Speaker 1: wondering about the nature of the universe. Our whole goal

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Speaker 1: here is to share our joy of our ignorance and

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Speaker 1: wondering about what's in the universe and helping you talk

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Speaker 1: to everybody in your life about it. Yes, so if

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Speaker 1: you're a kid listening to this podcast right now, we

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Speaker 1: want to thank you for listening. We're glad that you're here,

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Speaker 1: and I'm sure you have a lot of questions as

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Speaker 1: well as well as a lot of other kids. And

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Speaker 1: we have a whole box full of questions from kids,

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Speaker 1: that's right, So don't be shy to ask your parents

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Speaker 1: questions or to send your questions to us. We'd love

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Speaker 1: to tackle them. So to be on the podcast, we'll

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Speaker 1: be tackling kid questions about the universe. At least are

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Speaker 1: questions about kids or buy kids. These are the biggest

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Speaker 1: questions from the littlest people. These are questions about the

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Speaker 1: whole universe, about black holes, and about how things work,

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Speaker 1: you know, the kind of things that go through the

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Speaker 1: vines of an eight year old. And these are all

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Speaker 1: spontaneously generated, right like kids just sent this question in

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Speaker 1: with their parents, that's right. I don't know if the

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Speaker 1: parents put the kids up to it, or these are

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Speaker 1: actually child actors. I can't vouch for the veracity of these,

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Speaker 1: but they are good questions, and so I thought they'd

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Speaker 1: be fun to talk about on the podcast. Yes, so

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Speaker 1: long as you didn't go around soliciting little kids or

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Speaker 1: things on the internet, I think we're safe. No, I

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Speaker 1: try to stay as far away as I can from

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Speaker 1: the child acting industry down here in southern California. Yeah.

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Speaker 1: So we have all kinds of awesome questions here from

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Speaker 1: kids about black hole, about diamond cores, about the expanding universe,

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Speaker 1: and we have a whole bunch of him. So let's

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Speaker 1: dig into him. Daniel, what's our first question? Our first

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Speaker 1: question comes from Joey. He's seven years old. What are

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Speaker 1: the newest than the oldest black holes in the universe? Mmmm?

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Speaker 1: Appropriately A question about youngest and oldest something in the universe.

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Speaker 1: I wonder if there's a relationship there with like Grandpa

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Speaker 1: black holes and grandkid black holes. Yeah, like maybe the

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Speaker 1: younger black holes and more attitude, maybe they think they

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Speaker 1: had they know everything in the universe. I was thinking

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Speaker 1: the other direction, like maybe the little black holes look

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Speaker 1: up to the supermassive black holes and they're like, that's

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Speaker 1: gonna be me. One day. I'm gonna have my own

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Speaker 1: galaxy of stars swirling around me. I'm gonna devour millions

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Speaker 1: of stars and planets and potentially a civilizations and then

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Speaker 1: get bigger something. I'm gonna be huge and round. One day,

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Speaker 1: I'm gonna have a whole galaxy for bowling around me.

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Speaker 1: Just me. Yeah. So it's a great question because the

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Speaker 1: black holes weren't all made at this time. I guess

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Speaker 1: it's one thing that people may not know that black

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Speaker 1: holes are not all the same age. That's right, and

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Speaker 1: part of the reason is that we have several different

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Speaker 1: categories of black holes. We have different ways that black

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Speaker 1: holes could be made, so different processes that are capable

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Speaker 1: of creating this crazy density that you need to create

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Speaker 1: this craziest and most mysterious of universal objects. Yeah, so

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Speaker 1: there are black holes being born right now, and there

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Speaker 1: were maybe black holes that were made in the Big Bang.

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Speaker 1: So let's get into what we know, Daniel, What is

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Speaker 1: the youngest black hole that we know about? So we think,

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Speaker 1: as you say, that black holes are being made all

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Speaker 1: the time, right, because black holes come from collapsing stars,

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Speaker 1: at least one category do so. At the end of

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Speaker 1: the life of a star. We think that they collapse

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Speaker 1: and they form a black hole if they have enough mass,

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Speaker 1: and that should be happening basically all the time around

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Speaker 1: the universe. I mean, not like ten thousand every second

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Speaker 1: per cubic light year, but at a certain rate all

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Speaker 1: over the universe. So there should be a black hole

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Speaker 1: being made right now on another one right now, another

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Speaker 1: one right now. Every ten seconds, the black hole is born. Yeah,

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Speaker 1: it's like asking who is the youngest person on Earth.

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Speaker 1: It's a constantly changing answer because new babies are constantly

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Speaker 1: being born. But as you say, we can ask the question,

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Speaker 1: what is the youngest black hole that we have seen? Right?

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Speaker 1: And then there's another twist there, because you know, the

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Speaker 1: things that are further away from us are a little older.

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Speaker 1: So we're naturally going to have seen things that are younger,

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Speaker 1: that are closer to us, just because the light has

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Speaker 1: had a chance to reach us. Oh I see. So

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Speaker 1: there's kind of a delay between when something happens and

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Speaker 1: when we find out about it. So what we think

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Speaker 1: might be the youngest might not be the youngest. It's

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Speaker 1: just the youngest that we know about that the news

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Speaker 1: of which has gotten to us. Yeah, precisely. And so

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Speaker 1: the youngest black hole that we know about is about

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Speaker 1: twenty six thousand light years from Earth. It's called wt

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Speaker 1: B because astronomers are so creative with names, and we

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Speaker 1: think it's about a thousand years old. We think that

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Speaker 1: it was formed in a supernova that happened about a

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Speaker 1: thousand years ago. Supernova black hole. Now, not all stars

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Speaker 1: go supernova and become black holes, right, Like, there's lots

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Speaker 1: of stars that never become a black hole. Like, our

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Speaker 1: star is not going to become a black hole, that's right.

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Speaker 1: And our star won't even go supernova. And the whole

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Speaker 1: thing is determined just by how much stuff there is

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Speaker 1: in the original star. The more stuff there is, the

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Speaker 1: more likely that it's gonna have a supernova collapse. And

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Speaker 1: then only the heaviest of stars have enough mass to

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Speaker 1: create a black hole, because remember, to create a black hole,

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Speaker 1: you have to have gravity overcome all of the things

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Speaker 1: that are pushing back against gravity's pressure. Gravity is trying

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Speaker 1: to push everything into the smallest space possible because it's

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Speaker 1: just attracting mass to other mass. But things prevent that,

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Speaker 1: like our star is burning and shooting out radiation, which

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Speaker 1: prevents it from collapse. When that burning stops, then there

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Speaker 1: are other things that will prevent it from collapsing, like

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Speaker 1: just the atoms pushing against each other, or eventually just

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Speaker 1: like quantum mechanical effects. But if you have enough stuff,

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Speaker 1: you have a big enough scoop of original hydrogen serving,

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Speaker 1: then you can overcome that if you're above a minimum threshold.

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Speaker 1: So you're right, not every supernova becomes a black hole.

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Speaker 1: And so the youngest supernova and that that became a

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Speaker 1: black hole that we know about happened. We think a

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Speaker 1: thousand years ago, twenty six light years from Earth. Twenty

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Speaker 1: six thousand light years from twenty six thousands are light

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Speaker 1: years from Earth. What did I say? Twenty six thousand

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Speaker 1: miles light years? But hey, what's three years in magnitude

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Speaker 1: between friends? Yeah? It's right here, but really it must

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Speaker 1: have been then that it was maybe born twenty five

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Speaker 1: thousand light years or something like that years ago, Like

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Speaker 1: it can be a thousand years old, but then it's

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Speaker 1: twenty six thousand light years away, because it would take

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Speaker 1: twenty six thousand years for the light to get to us.

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Speaker 1: That's right. What we mean by that is the supernova

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Speaker 1: should have been visible here on Earth a thousand years ago, right,

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Speaker 1: And so a thousand years ago we should have seen

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Speaker 1: a supernova indicating the formation of the black hole. But

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Speaker 1: of course that would have happened twenty seven thousand years ago.

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Speaker 1: I guess, how do we know that it's there or

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Speaker 1: how do we know it's age? Like black holes are black,

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Speaker 1: so they're kind of hard to see in space. How

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Speaker 1: do we know it's there? And how do we know

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Speaker 1: how old it is? So these are tricky to identify. Right,

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Speaker 1: every time you see a supernova, you don't necessarily get

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Speaker 1: a black hole, and so you can't actually see these

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Speaker 1: black holes directly. You always have to infer it indirectly,

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Speaker 1: and so you see for example, in acretion disc forming,

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Speaker 1: but you don't see any object there at the core,

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Speaker 1: or perhaps you can measure the mass because there's something

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Speaker 1: else nearby, and you can measure the radios because things

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Speaker 1: are passing near it, and so you can tell what

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Speaker 1: the density of the object is. And it's denser than

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Speaker 1: a neutron star could be. And so, as we talked

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Speaker 1: about on a recent episode about black holes, we're never

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Speaker 1: a hundred sure about a black hole. Were always inferring

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Speaker 1: in the argument is usually something like this is denser

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Speaker 1: than a neutron star could be or anything we know,

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Speaker 1: therefore it must be a black hole. There's always a

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Speaker 1: bit of a leap there, like we don't know anything

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Speaker 1: other than a black hole that could be this small

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Speaker 1: and this dense, So therefore we think it's a black hole.

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Speaker 1: And that's sort of the argument we make when we

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Speaker 1: look at these nebula, right you sort of look at

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Speaker 1: it black spot in the in space and you see

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Speaker 1: things moving around it in an orbit, and so you

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Speaker 1: mustn't for that there's something like a black holder. But

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Speaker 1: I guess, how do you know it's a thousand years old?

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Speaker 1: Like how do you know when it happened? Like we

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Speaker 1: weren't looking a thousand years ago? That's right, But these

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Speaker 1: things have clouds, right, The supernova is an active process,

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Speaker 1: and so there's a big explosion and a lot of

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Speaker 1: the stuff gets thrown out to form this nebula and

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Speaker 1: some of it collapses into the black hole. But we

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Speaker 1: can watch the process of this nebula and it's going

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Speaker 1: to like create new planets and have all sorts of dynamics,

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Speaker 1: and so that's sort of a thing that we can

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Speaker 1: watch and we can look at and we can say, well,

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Speaker 1: this nebula looks like it's about a thousand years old,

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Speaker 1: because we think it looks like about a thousand years

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Speaker 1: worth of like gravitational reformation has happened. You can see

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Speaker 1: the wrinkles. You don't have to check the idea. You

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Speaker 1: can just guess by looking at it. You can measure

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Speaker 1: the velocity of things in the nebula by seeing the

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Speaker 1: red shift, and so you can sort of tell where

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Speaker 1: it is in this process of having exploded and then

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Speaker 1: reforming something. Sometimes you'll get like new planets forming around

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Speaker 1: the neutron star or the black hole at the core.

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Speaker 1: Well that's cool. So then that's the youngest black hole

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Speaker 1: we've ever seen, Like we haven't seen one in the

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Speaker 1: last thousand years, or we don't think one has come

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Speaker 1: into existence in the last thousand years. Isn't that weird?

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Speaker 1: Given how many stars there are in the galaxy and

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Speaker 1: in the universe. It is kind of weird. And there's

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Speaker 1: a couple of things going on there. One is that

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Speaker 1: there aren't that many supernova in our galaxy, Like there's

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Speaker 1: a lot of stars in our galaxy, and we expect

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Speaker 1: only like a few supernova per century because not many

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Speaker 1: stars actually end up turning into supernova. And one of

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Speaker 1: the weird things is that we haven't seen a supernova

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Speaker 1: in more than four hundred years, like the last supernova

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Speaker 1: in the Milky Way that we saw. We see lots

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Speaker 1: of them in other galaxies constantly, hundreds every year, but

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Speaker 1: the last one that we saw in our galaxy was

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Speaker 1: in sixteen o four. Kepler saw the last supernova any

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Speaker 1: human has ever observed in our galaxy. Whoa really, how

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Speaker 1: do you know we didn't miss it? Like in the

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Speaker 1: eighteen hundreds for everyone with everyone looking, was everyone looking diligently,

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Speaker 1: Like what if we kind of like one happened and

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Speaker 1: we were looking the other way, or you know, the

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Speaker 1: French Revolution was happening that the we were a little busy,

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Speaker 1: or World War two is happening, and so there are

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Speaker 1: other things we were attending to do. Yeah, there are.

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Speaker 1: There are a couple of candidates where we see in Nebula,

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Speaker 1: were like, Hm, this looks like it should have been

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Speaker 1: a supernova about a hundred years ago. We should have

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Speaker 1: seen it. Why didn't anybody notice it? There are a

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Speaker 1: couple of candidates, but even still is kind of weird

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Speaker 1: because we expect a few per century and we haven't

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Speaker 1: seen a single one in four hundred years. We're actually

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Speaker 1: gonna dig into that in a whole podcast episode about

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Speaker 1: the formation of supernov and why we haven't seen any

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Speaker 1: in the Milky Way pretty soon. But basically, we haven't

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Speaker 1: seen a lot of supernova in the Milky Way recently,

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Speaker 1: and you need a supernova to form these black holes,

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Speaker 1: all right, So then the answer is stay tuned. But

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Speaker 1: that is the youngest black hole we've seen. It's a

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Speaker 1: thousand years old, twenty six thousand light years from Earth,

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Speaker 1: and so what's the oldest black hole we know about?

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Speaker 1: The oldest black holes we know about are ones that

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Speaker 1: formed at the hearts of galaxies the very beginning of

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Speaker 1: the universe. Remember that after the Big Bang stuff flew

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Speaker 1: out and then gravity started doing its job and made

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Speaker 1: stars and galaxies, and that took about a billion years

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Speaker 1: for the universe to look familiar, you know, eight hundred million,

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Speaker 1: maybe a billion years before we had the first galaxies.

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Speaker 1: And the interesting thing is that we already have supermassive

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Speaker 1: black holes at the hearts of those galaxies. Now, those

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Speaker 1: galaxies are billions of years old, which means we can

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Speaker 1: only see them if they're very very far away, because

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Speaker 1: the light from those far away galaxies is just now

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Speaker 1: hitting Earth. So if you look deep out into space,

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Speaker 1: you're looking back in time and you're looking at the

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Speaker 1: very very early galaxies. And the crazy thing is at

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Speaker 1: the heart of those galaxies there are these very bright emissions,

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Speaker 1: these things we called quaisars, which are light from the

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Speaker 1: gas that's surrounding those huge black holes in the very

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Speaker 1: early universe. So we think that black holes were formed

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Speaker 1: at the heart of these early galaxies, you know, just

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Speaker 1: a few hundred million years after the Big Bang. M interesting,

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Speaker 1: so we can see these black holes because they're actually

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Speaker 1: really shiny, or at least what's around them is really shiny.

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Speaker 1: In fact, super shiny. Right, It's like it's brighter than

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Speaker 1: the whole galaxy that it's in. That's right. They are

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Speaker 1: crazy shiny. These things are called quasars, and when they

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Speaker 1: were first discovered, people didn't really understand. They didn't believe

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Speaker 1: them if there must be something wrong because you're looking

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Speaker 1: at something super distant and yet super bright, which means

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Speaker 1: that added source, it must be like riduculously bright. And

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Speaker 1: people thought that just must be wrong. What could power that.

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Speaker 1: Then they discover that, oh, it's the energy from these

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Speaker 1: black holes that's like squeezing and pushing on all this

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Speaker 1: gas around it that creates this very intense radiation. Again

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Speaker 1: not from the black hole, as you say, but from

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Speaker 1: the gas that's around it. And so you're saying that

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Speaker 1: we see these quasars, these super bright black holes in

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Speaker 1: galaxies that are really really far away, which means that

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Speaker 1: they're really really old, which puts their age at around

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Speaker 1: thirteen billion years old. We think the black hole is

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Speaker 1: thirteen billion years old. Yeah, we think the black hole

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Speaker 1: is thirteen billion years old. Now we haven't seen them recently, right,

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Speaker 1: we are looking at very outdated information. So we're looking

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Speaker 1: at a black hole which is fairly young, maybe a

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Speaker 1: few hundred million years, but thirteen billion years ago. So

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Speaker 1: now we're assuming that those black holes are still around

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Speaker 1: because we don't know of any mechanism for super massive

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Speaker 1: black holes to disappear. The only way a black hole

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Speaker 1: can shrink is through hawking radiation, but that happens very

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Speaker 1: very gradually for very large black holes, and these things

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Speaker 1: are probably still eating, so they're probably even bigger now

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Speaker 1: than we are seeing them from thirteen billion years ago. Well,

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Speaker 1: it's like getting a photograph of someone from the nineteen twenties,

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Speaker 1: and you know, assuming they're still alive, that would make

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Speaker 1: them really old, just because you have a photo of

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Speaker 1: them when they were young, but the photo is really old. Yeah, exactly.

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Speaker 1: So these things been around basically the entire history of

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Speaker 1: the universe, right, almost though almost by like what a

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Speaker 1: hundred thousand years you said, a few hundred million years

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Speaker 1: order between a podcast hook covers. That's right, exactly, So

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Speaker 1: those are pretty old. Thirteen billion years old is pretty old.

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Speaker 1: But there might be even older black holes, that's right.

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Speaker 1: We don't know, but it's possible that there were black

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Speaker 1: holes made before there was even matter, for the universe

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Speaker 1: cooled down so that the energy in the quantum fields

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Speaker 1: could even be described as like particles as you know,

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Speaker 1: like corks and electrons flying around when the universe is

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Speaker 1: still so crazy dense and intense that you couldn't even

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Speaker 1: describe things as particles. We think there might have been

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Speaker 1: black holes made in that state of matter, and those

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Speaker 1: we call primordial black holes. I see, because you don't

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Speaker 1: necessarily need matter to make a black hole, right, you

398
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Speaker 1: could also make one out of pure energy. That's right,

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Speaker 1: because general relativity treats matters just another form of energy,

400
00:19:32,000 --> 00:19:35,119
Speaker 1: and it's really energy density that curves space, and so

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Speaker 1: you can accomplish that with matter, of course, but you

402
00:19:37,359 --> 00:19:39,920
Speaker 1: could also accomplish that with energy. Like if you take

403
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Speaker 1: powerful enough lasers and overlap them, you can create a

404
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Speaker 1: black hole out of light. How about liquid niitrogen lightsabers?

405
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Speaker 1: What if you cross those beams? Can you cut a

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Speaker 1: black hole in half with a lightsaber? There's a physics

407
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Speaker 1: question I don't have the answer to. Only here, Yoda,

408
00:19:57,760 --> 00:20:01,320
Speaker 1: only after nine engineers of training. So least primordial black

409
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Speaker 1: holes would be the oldest black holes in the universe.

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Speaker 1: But we don't really know if they exist, right, We

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Speaker 1: definitely do not know if they exist. If they did exist,

412
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Speaker 1: we should be seeing them, because they should have been

413
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Speaker 1: created all sorts of different sizes, really large ones, really

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Speaker 1: small ones. It's nice to imagine that they might exist

415
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Speaker 1: because they might explain how supermassive black holes got so

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Speaker 1: massive so young, Like you might ask, how do you

417
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Speaker 1: get such a big black hole after only a few

418
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Speaker 1: hundred million years? While they could have been seeded by

419
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Speaker 1: primordial black holes, they could also explain what the dark

420
00:20:31,640 --> 00:20:33,720
Speaker 1: matter is. Maybe dark matter is just a bunch of

421
00:20:33,720 --> 00:20:37,080
Speaker 1: these primordial black holes floating around in the universe. But

422
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Speaker 1: if they were creating all sorts of different sizes, then

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Speaker 1: some of them should be just the right size to

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Speaker 1: live around fourteen billion years and then evaporate to disappear.

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Speaker 1: And when black holes evaporate, they're giving off their light.

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Speaker 1: It happens more rapidly. They get brighter and brighter as

427
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Speaker 1: they're about to disappear, so we should be able to

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Speaker 1: see them sort of like flashing out of existence. But

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Speaker 1: we've never seen that happen, and so it's sort of

430
00:21:00,400 --> 00:21:03,439
Speaker 1: hard to understand how you can have primordial black holes.

431
00:21:04,200 --> 00:21:07,200
Speaker 1: Maybe they feel out, you know, kind of silent. Maybe

432
00:21:07,200 --> 00:21:09,320
Speaker 1: they don't feel a lot with a bang. Is that

433
00:21:09,359 --> 00:21:12,760
Speaker 1: possible it's possible, but our current theory of black hole

434
00:21:12,800 --> 00:21:16,360
Speaker 1: evaporation suggests that when they evaporate they turn into photons

435
00:21:16,400 --> 00:21:18,719
Speaker 1: and also to other crazy particles, and we should definitely

436
00:21:18,720 --> 00:21:21,000
Speaker 1: be seeing those, like at the edges of the galaxy

437
00:21:21,119 --> 00:21:22,920
Speaker 1: or something. But we've been looking and we haven't seen

438
00:21:22,960 --> 00:21:25,640
Speaker 1: a single one. We've never seen a black hole evaporation,

439
00:21:26,080 --> 00:21:28,959
Speaker 1: and so that suggests that probably they're either just not

440
00:21:29,119 --> 00:21:31,600
Speaker 1: formed in the right sizes, like maybe their only form

441
00:21:31,640 --> 00:21:34,679
Speaker 1: really really small and really really big. That's possible, or

442
00:21:34,720 --> 00:21:37,520
Speaker 1: they just weren't made. But if they were made, then

443
00:21:37,560 --> 00:21:40,640
Speaker 1: they'd be essentially as old as the universe. They would

444
00:21:40,640 --> 00:21:44,280
Speaker 1: be made like less than a second after the Big Bang. Interesting,

445
00:21:44,320 --> 00:21:46,480
Speaker 1: But isn't it a theory that some of those super

446
00:21:46,480 --> 00:21:49,040
Speaker 1: massive black holes in the middle of galaxies maybe we're

447
00:21:49,280 --> 00:21:52,560
Speaker 1: made by primordial black holes. It could be, yeah, because

448
00:21:52,560 --> 00:21:54,960
Speaker 1: as we said, we don't understand how those black holes

449
00:21:55,000 --> 00:21:57,680
Speaker 1: got so big so fast. If you try to model

450
00:21:57,720 --> 00:22:00,800
Speaker 1: the formation of galaxies in the early universe, stars coming

451
00:22:00,840 --> 00:22:03,800
Speaker 1: together forming a black hole, cetera, you can't get black

452
00:22:03,800 --> 00:22:06,880
Speaker 1: holes that are like billions of solar masses so quickly.

453
00:22:07,040 --> 00:22:08,880
Speaker 1: So we just don't understand how that happened. And as

454
00:22:08,920 --> 00:22:11,400
Speaker 1: you say, one idea is maybe they got a jump

455
00:22:11,480 --> 00:22:14,679
Speaker 1: start because they were seeded by a really big primordial

456
00:22:14,720 --> 00:22:17,600
Speaker 1: black hole. So that's a possibility. So it sounds like

457
00:22:17,640 --> 00:22:20,000
Speaker 1: the oldest black holes in the universe are thirteen billion

458
00:22:20,119 --> 00:22:23,119
Speaker 1: years old at least at least it might be older.

459
00:22:23,359 --> 00:22:25,480
Speaker 1: All right, Well, thank you Joy for a great question.

460
00:22:25,520 --> 00:22:28,320
Speaker 1: I think that's your answer. The youngest and the oldest

461
00:22:28,320 --> 00:22:31,240
Speaker 1: black holes in the universe are both still older than

462
00:22:31,240 --> 00:22:34,280
Speaker 1: your parents apparently, but maybe billions of years or at

463
00:22:34,320 --> 00:22:37,200
Speaker 1: least a thousand years and maybe billions of years. That's right.

464
00:22:37,600 --> 00:22:40,560
Speaker 1: These black holes make your parents seem like children. All right,

465
00:22:40,640 --> 00:22:42,840
Speaker 1: Thank you, Joey. And so let's get into more questions

466
00:22:42,840 --> 00:22:58,679
Speaker 1: from kids. But first let's take a quick break. All right,

467
00:22:58,800 --> 00:23:02,600
Speaker 1: we are answering kids questions about the universe on today's episode,

468
00:23:02,720 --> 00:23:06,000
Speaker 1: and we have some pretty cool questions here, Daniel, or

469
00:23:06,000 --> 00:23:08,399
Speaker 1: any of these questions from your own kids. None of

470
00:23:08,400 --> 00:23:10,919
Speaker 1: these questions are from my kids. These are questions that

471
00:23:10,920 --> 00:23:12,960
Speaker 1: people didn't have the answers too, so they wanted me

472
00:23:13,040 --> 00:23:15,320
Speaker 1: to answer them. If my kids ask me questions, I

473
00:23:15,440 --> 00:23:17,439
Speaker 1: just answered them, or if I don't know the answer,

474
00:23:18,000 --> 00:23:19,680
Speaker 1: I try to look it up, but I don't send

475
00:23:19,680 --> 00:23:22,200
Speaker 1: them to the podcast. I see you're like a pinch

476
00:23:22,280 --> 00:23:25,800
Speaker 1: hit hitter for parents when it comes to physics questions. Yeah,

477
00:23:25,800 --> 00:23:27,600
Speaker 1: I try to be. I think that's a lot of fun.

478
00:23:27,840 --> 00:23:30,200
Speaker 1: I just love hearing the kinds of questions that other

479
00:23:30,280 --> 00:23:33,320
Speaker 1: kids are asking because it tells you something about how

480
00:23:33,359 --> 00:23:35,280
Speaker 1: they see the universe. And you know, I feel like

481
00:23:35,560 --> 00:23:38,040
Speaker 1: my brain is sort of like stuck in the modern

482
00:23:38,119 --> 00:23:41,080
Speaker 1: physics view of how things work, and I'm sure to

483
00:23:41,160 --> 00:23:44,000
Speaker 1: have all sorts of like misconceptions that have sort of

484
00:23:44,040 --> 00:23:46,840
Speaker 1: fallen into and been thinking about for twenty years. So

485
00:23:46,880 --> 00:23:48,680
Speaker 1: a kid's question can really stop you in your tracks

486
00:23:48,680 --> 00:23:50,560
Speaker 1: and ask you like, how do we know this? Or

487
00:23:50,720 --> 00:23:54,520
Speaker 1: why do we think about it this way? It's really refreshing, alright.

488
00:23:54,520 --> 00:23:57,639
Speaker 1: Our next question comes from Anthony, who has a question

489
00:23:57,680 --> 00:24:03,600
Speaker 1: about diamond core Daniel and horror. Hey, my name is Anthony.

490
00:24:03,640 --> 00:24:07,640
Speaker 1: I am eight years old, and why does fifty king

491
00:24:07,800 --> 00:24:11,840
Speaker 1: trying eat have a diamond core? Looking forward to hear

492
00:24:12,040 --> 00:24:15,919
Speaker 1: your answer, pleasing, thank you, Hey, thanks Anthony. What a

493
00:24:15,960 --> 00:24:19,520
Speaker 1: polite little young person. I know they said please and

494
00:24:19,520 --> 00:24:22,800
Speaker 1: thank you. Some of our listeners apparently are teaching their

495
00:24:22,880 --> 00:24:25,720
Speaker 1: kids manners in addition to science, can Anthony talk to

496
00:24:25,760 --> 00:24:29,400
Speaker 1: my kids please and run a little etiquette class? That's right,

497
00:24:29,440 --> 00:24:31,199
Speaker 1: and we will trae you some physics answers for some

498
00:24:31,280 --> 00:24:35,000
Speaker 1: manner's lessons. Now, this is an interesting question because, to

499
00:24:35,040 --> 00:24:37,240
Speaker 1: be honest, I didn't quite understand it. It almost sounded

500
00:24:37,280 --> 00:24:39,840
Speaker 1: like a Star Wars reference, like does this kind of

501
00:24:39,920 --> 00:24:43,760
Speaker 1: lightsaber model have a crystal core? It's a great question.

502
00:24:43,840 --> 00:24:47,200
Speaker 1: It's about an exo planet. This is the planet around

503
00:24:47,240 --> 00:24:50,520
Speaker 1: another star that we're trying to understand because you know,

504
00:24:50,800 --> 00:24:53,200
Speaker 1: we are looking at our own Solar system and wondering

505
00:24:53,320 --> 00:24:55,360
Speaker 1: are these the only kinds of planets you can have

506
00:24:55,680 --> 00:24:58,160
Speaker 1: or are there other weird kinds of planets out there.

507
00:24:58,359 --> 00:25:01,000
Speaker 1: As always, when we venture out from our little corner

508
00:25:01,080 --> 00:25:03,480
Speaker 1: of the universe, we expect to be shocked. We look

509
00:25:03,560 --> 00:25:06,199
Speaker 1: forward to seeing things that we couldn't have imagined. And

510
00:25:06,280 --> 00:25:08,520
Speaker 1: so this is a planet around another star, and we're

511
00:25:08,520 --> 00:25:10,320
Speaker 1: trying to understand what it's made out of it, you know,

512
00:25:10,400 --> 00:25:13,159
Speaker 1: like what it's like to walk on its surface. And

513
00:25:13,200 --> 00:25:15,840
Speaker 1: so there was a recent paper suggesting that maybe the

514
00:25:16,080 --> 00:25:19,560
Speaker 1: entire core of this planet could be one huge diamond,

515
00:25:19,800 --> 00:25:22,440
Speaker 1: and that's what Anthony is asking about WHOA. Yeah, because

516
00:25:22,440 --> 00:25:25,800
Speaker 1: we've seen now thousands and thousands of planets in other

517
00:25:25,960 --> 00:25:28,920
Speaker 1: solar systems, right like, we've detected them, we've even sort

518
00:25:28,920 --> 00:25:30,760
Speaker 1: of sort of have pictures of them. We can tell

519
00:25:30,800 --> 00:25:32,920
Speaker 1: what's in their atmosphere. Are we down to the point

520
00:25:32,920 --> 00:25:35,800
Speaker 1: where you can tell what's inside these planets out there

521
00:25:35,800 --> 00:25:37,760
Speaker 1: in space? We sort of can. And you know, we

522
00:25:37,800 --> 00:25:40,639
Speaker 1: have very limited information about each one of these things,

523
00:25:40,920 --> 00:25:42,960
Speaker 1: and so we're trying to do as much science as

524
00:25:43,000 --> 00:25:46,560
Speaker 1: we can with a very basic information. And here, for example,

525
00:25:46,640 --> 00:25:49,280
Speaker 1: we have like some knowledge about the mass of the

526
00:25:49,320 --> 00:25:52,360
Speaker 1: planet and then some knowledge of the radius of the planet,

527
00:25:52,560 --> 00:25:54,480
Speaker 1: and that lets you do really basic stuff like ask

528
00:25:54,640 --> 00:25:56,639
Speaker 1: what's the density of the planet. And if you know

529
00:25:56,680 --> 00:25:58,840
Speaker 1: what the density is, then you can ask questions like, well,

530
00:25:58,840 --> 00:26:01,720
Speaker 1: what could make a plant of that density? What materials

531
00:26:01,760 --> 00:26:04,600
Speaker 1: are consistent with that? So now we can't like go

532
00:26:04,640 --> 00:26:06,480
Speaker 1: and drill into the planet and say, oh, look, we

533
00:26:06,560 --> 00:26:09,480
Speaker 1: found diamond, but we can ask questions about what it

534
00:26:09,560 --> 00:26:11,560
Speaker 1: might be met out of based on what we do know.

535
00:26:11,920 --> 00:26:15,560
Speaker 1: Interesting and athink it was asking about a specific planet

536
00:26:15,600 --> 00:26:17,159
Speaker 1: that has been found out there, and he had a

537
00:26:17,240 --> 00:26:20,040
Speaker 1: name for it. It was fifty five something. Yeah, the

538
00:26:20,080 --> 00:26:22,920
Speaker 1: official name of the planet is fifty five can create E,

539
00:26:23,520 --> 00:26:27,679
Speaker 1: and so sometimes abbreviated fifty five C E can create E.

540
00:26:27,880 --> 00:26:30,080
Speaker 1: That does sound like a star trek name. It's a

541
00:26:30,080 --> 00:26:33,720
Speaker 1: planet that's orbiting the star. Fifty five can create A

542
00:26:34,440 --> 00:26:37,040
Speaker 1: and so can create E. Is you know, like one

543
00:26:37,080 --> 00:26:40,240
Speaker 1: of the things around can create A. I see there's

544
00:26:40,240 --> 00:26:42,399
Speaker 1: a B S D N A D. But we're talking

545
00:26:42,400 --> 00:26:45,040
Speaker 1: about the thing around that star. That's right. This is

546
00:26:45,040 --> 00:26:47,640
Speaker 1: the one that's most interesting, and it's kind of really

547
00:26:47,680 --> 00:26:50,800
Speaker 1: interesting history to it because it was first discovered in

548
00:26:50,840 --> 00:26:54,359
Speaker 1: two thousand four using the Wiggle method. The Wiggle method

549
00:26:54,400 --> 00:26:57,720
Speaker 1: says that a planet moving around a star should tug

550
00:26:57,760 --> 00:27:00,240
Speaker 1: on the star. It's not just that the stars pulling

551
00:27:00,240 --> 00:27:02,480
Speaker 1: on the planet. The planet is pulling on the star.

552
00:27:03,000 --> 00:27:04,840
Speaker 1: And so if you have a planet moving around the star,

553
00:27:04,920 --> 00:27:07,800
Speaker 1: you should see the star moving also, and you can

554
00:27:07,840 --> 00:27:10,440
Speaker 1: measure that by measuring the velocity of the star by

555
00:27:10,440 --> 00:27:13,520
Speaker 1: seeing how much it changes the light that's coming to

556
00:27:13,640 --> 00:27:16,760
Speaker 1: us from the star. So these doppler shifts, right, just

557
00:27:16,880 --> 00:27:19,159
Speaker 1: like like the Earth is making the Sun wiggle a

558
00:27:19,200 --> 00:27:21,800
Speaker 1: little tiny bit. And if you were you know, smart

559
00:27:21,880 --> 00:27:24,800
Speaker 1: knife and had pretty good tascos in another galaxy or

560
00:27:24,840 --> 00:27:27,520
Speaker 1: another planet, you could tell that we were here, And

561
00:27:27,520 --> 00:27:29,280
Speaker 1: so you can tell if there's a planet there because

562
00:27:29,280 --> 00:27:32,480
Speaker 1: it's pulling on the star, and you can tell something

563
00:27:32,640 --> 00:27:35,080
Speaker 1: about the mass of the planet because you can tell

564
00:27:35,119 --> 00:27:37,840
Speaker 1: how much it's pulling on the star, and you can

565
00:27:37,840 --> 00:27:40,320
Speaker 1: tell something about its period because you can tell, like

566
00:27:40,359 --> 00:27:42,840
Speaker 1: how when the star wiggles one way and the other way.

567
00:27:42,960 --> 00:27:45,199
Speaker 1: But this wiggle method doesn't tell you anything about the

568
00:27:45,280 --> 00:27:47,439
Speaker 1: size of the planet because you know, you don't know

569
00:27:47,480 --> 00:27:50,560
Speaker 1: if it's like a big fluffy pile of styrofoam or

570
00:27:50,600 --> 00:27:53,120
Speaker 1: a tiny little black hole. They would have the same

571
00:27:53,200 --> 00:27:56,399
Speaker 1: gravitational effect on the star, right, they would wiggle the

572
00:27:56,440 --> 00:27:58,360
Speaker 1: star in the same way. And so that was two

573
00:27:58,359 --> 00:28:01,440
Speaker 1: thousand four. All we knew about this thing was how

574
00:28:01,480 --> 00:28:04,280
Speaker 1: long it took to go around its Sun and how

575
00:28:04,359 --> 00:28:07,359
Speaker 1: massive it was. But then like seven years later, we

576
00:28:07,359 --> 00:28:09,800
Speaker 1: got better telescopes and we trained them on the star

577
00:28:10,200 --> 00:28:12,399
Speaker 1: and we were able to measure the size of this

578
00:28:12,480 --> 00:28:15,359
Speaker 1: planet by seeing it eclipsing its star. Like you know,

579
00:28:15,400 --> 00:28:17,040
Speaker 1: if you go out and you watching eclipse, you see

580
00:28:17,080 --> 00:28:18,840
Speaker 1: the Moon passing in front of the Sun and it

581
00:28:18,880 --> 00:28:21,080
Speaker 1: blocks it out it's very dramatic. This is very different

582
00:28:21,080 --> 00:28:23,440
Speaker 1: because the planet is much much smaller than the star,

583
00:28:23,960 --> 00:28:26,080
Speaker 1: and so it's sort of like watching a moth lock

584
00:28:26,119 --> 00:28:28,240
Speaker 1: in front of a light bulb from like thousands of

585
00:28:28,280 --> 00:28:30,919
Speaker 1: miles away and then measuring how much the light bulb

586
00:28:30,960 --> 00:28:33,159
Speaker 1: dims because of the moth And you can use that

587
00:28:33,200 --> 00:28:35,919
Speaker 1: to measure the size of the planet, because the larger

588
00:28:35,920 --> 00:28:39,160
Speaker 1: planet would dim the star more than a smaller planet. Right.

589
00:28:39,240 --> 00:28:41,440
Speaker 1: Or if you're like looking at the Moon at night,

590
00:28:41,480 --> 00:28:45,320
Speaker 1: for example, and a little fly between you and the Moon,

591
00:28:45,360 --> 00:28:47,360
Speaker 1: you would sort of see the light from the Moon,

592
00:28:47,840 --> 00:28:50,560
Speaker 1: you know, get a little bit dimmer. But it's just

593
00:28:50,600 --> 00:28:53,240
Speaker 1: a little tiny bit, just a little tiny bit. But

594
00:28:53,440 --> 00:28:54,920
Speaker 1: if you watch, you can see it. And you can

595
00:28:54,960 --> 00:28:58,000
Speaker 1: see it happened periodically also, which really helps. It's not

596
00:28:58,080 --> 00:29:00,240
Speaker 1: just like one blip and you say, oh, is that

597
00:29:00,360 --> 00:29:03,360
Speaker 1: noise or mistake in my data. If it happens periodically

598
00:29:03,400 --> 00:29:06,880
Speaker 1: regularly and it matches up with the velocity measurements you're

599
00:29:06,920 --> 00:29:09,120
Speaker 1: making of the star, that you can be pretty confident

600
00:29:09,160 --> 00:29:11,480
Speaker 1: that that's what you're seeing, So then you know the

601
00:29:11,600 --> 00:29:13,920
Speaker 1: size of the planet. Also from that, you can make

602
00:29:13,960 --> 00:29:16,440
Speaker 1: measurements of its density and you can know like something

603
00:29:16,440 --> 00:29:18,240
Speaker 1: about what it's made out of. So you can tell

604
00:29:18,240 --> 00:29:21,000
Speaker 1: the mass from the wiggle, and you can tell the

605
00:29:21,200 --> 00:29:23,520
Speaker 1: size from the shadow it makes in front of the

606
00:29:23,520 --> 00:29:26,480
Speaker 1: that star. And so we have a measure of its density,

607
00:29:26,520 --> 00:29:28,400
Speaker 1: and I'm guessing it must be pretty dense if we're

608
00:29:28,400 --> 00:29:30,760
Speaker 1: thinking it might be made out of diamond core. Yeah,

609
00:29:30,800 --> 00:29:33,800
Speaker 1: this thing is like nine times the massive the Earth,

610
00:29:34,280 --> 00:29:37,160
Speaker 1: but its diameter is only twice the Earth, right, and

611
00:29:37,240 --> 00:29:40,200
Speaker 1: so it's definitely denser than the Earth is by how

612
00:29:40,280 --> 00:29:42,880
Speaker 1: much like three or four times? Yeah, Well, the diameter

613
00:29:42,960 --> 00:29:46,520
Speaker 1: of twice the Earth means that is volume is eight

614
00:29:46,560 --> 00:29:49,000
Speaker 1: times the Earth, right, and it's got a massive nine

615
00:29:49,000 --> 00:29:50,960
Speaker 1: times the Earth, So it's actually only a little bit

616
00:29:51,000 --> 00:29:53,080
Speaker 1: denser than the Earth is. So it must be like

617
00:29:53,120 --> 00:29:56,160
Speaker 1: a rocky planet or something, but it's just a little

618
00:29:56,160 --> 00:29:58,080
Speaker 1: bit more dense than the Earth. And the Earth is

619
00:29:58,080 --> 00:30:00,080
Speaker 1: pretty dense, right, Like the Earth is a rock you

620
00:30:00,120 --> 00:30:02,719
Speaker 1: planet with lava and rock, right, it's not. We're not

621
00:30:02,760 --> 00:30:05,600
Speaker 1: made out of a coun candy exactly. But this planet

622
00:30:05,640 --> 00:30:07,680
Speaker 1: is very different from the Earth because it's so close

623
00:30:07,720 --> 00:30:11,240
Speaker 1: to its son and it has an eighteen hour orbit,

624
00:30:11,640 --> 00:30:14,200
Speaker 1: like it takes eighteen hours for a year to pass

625
00:30:14,240 --> 00:30:16,440
Speaker 1: on this planet, like it goes around its son every

626
00:30:16,480 --> 00:30:21,280
Speaker 1: eighteen hours. Every eighteen hours there's a birthday party. It's

627
00:30:21,320 --> 00:30:24,760
Speaker 1: spent basically all of your time shopping for presents, an

628
00:30:24,760 --> 00:30:27,440
Speaker 1: opening presence, half the time shopping the o they have

629
00:30:27,600 --> 00:30:30,160
Speaker 1: opening them, that's right, and eating cake. And that makes

630
00:30:30,160 --> 00:30:33,200
Speaker 1: the surface of this planet very, very hot, like three thousand,

631
00:30:33,280 --> 00:30:38,680
Speaker 1: nine hundred degrees fahrenheit or c that's hot. That's pretty hot.

632
00:30:38,800 --> 00:30:41,200
Speaker 1: You don't need to lie your birthday candle. They're already

633
00:30:41,240 --> 00:30:43,920
Speaker 1: on fire, so I recommend a pool party. And that's

634
00:30:43,960 --> 00:30:47,040
Speaker 1: important to understand because when you're building models of these planets,

635
00:30:47,240 --> 00:30:50,280
Speaker 1: you have to understand like what state the materials that

636
00:30:50,320 --> 00:30:52,320
Speaker 1: you're putting into your model of the planet are. So

637
00:30:52,400 --> 00:30:55,360
Speaker 1: for example, they started off by assuming that this planet,

638
00:30:55,440 --> 00:30:57,800
Speaker 1: like Earth, has a lot of oxygen in it, Like

639
00:30:57,960 --> 00:31:00,040
Speaker 1: Earth is a lot of oxygen that doesn't have a

640
00:31:00,040 --> 00:31:02,200
Speaker 1: whole lot of carbon in it. And if you're going

641
00:31:02,240 --> 00:31:04,560
Speaker 1: to have a planet this size and with a lot

642
00:31:04,560 --> 00:31:06,400
Speaker 1: of oxygen in it, it should have a lot of

643
00:31:06,440 --> 00:31:08,920
Speaker 1: water on it. But it's sort of weird to have

644
00:31:09,160 --> 00:31:11,920
Speaker 1: all that water on the surface, like this planet would

645
00:31:11,960 --> 00:31:14,440
Speaker 1: be like ten water ten percent of the mass of

646
00:31:14,440 --> 00:31:16,400
Speaker 1: this planet would be watering to get the right size

647
00:31:16,440 --> 00:31:18,840
Speaker 1: and their identsity. But if you have that much water,

648
00:31:18,920 --> 00:31:22,240
Speaker 1: you're basically talking an ocean planet, but that much radiation

649
00:31:22,400 --> 00:31:24,800
Speaker 1: on the surface which split all the water and put

650
00:31:24,800 --> 00:31:27,320
Speaker 1: it in a supercritical state. So sort of a weird

651
00:31:27,400 --> 00:31:29,280
Speaker 1: idea to begin with. A right, it's not a good

652
00:31:29,280 --> 00:31:31,760
Speaker 1: assumption to think it's just like the Earth. Yeah, So

653
00:31:31,800 --> 00:31:34,000
Speaker 1: then what happened to convince them that maybe this planet

654
00:31:34,000 --> 00:31:36,720
Speaker 1: was different was that they learned something about the star.

655
00:31:36,920 --> 00:31:39,280
Speaker 1: They looked in more depth at what the star was

656
00:31:39,360 --> 00:31:41,400
Speaker 1: made out of, and they noticed that it had a

657
00:31:41,400 --> 00:31:44,160
Speaker 1: lot of carbon in it, a lot more carbon than

658
00:31:44,320 --> 00:31:47,440
Speaker 1: our star. For example, remember that these solar systems are

659
00:31:47,520 --> 00:31:51,560
Speaker 1: formed from leftover materials from other generations of solar systems,

660
00:31:51,560 --> 00:31:54,200
Speaker 1: So you have still mostly hydrogen, but like some of

661
00:31:54,200 --> 00:31:56,640
Speaker 1: them have more oxygen, some of them more carbon, some

662
00:31:56,680 --> 00:31:57,960
Speaker 1: of them have more of this, some of them have

663
00:31:58,040 --> 00:32:00,640
Speaker 1: more of that. This solar system seemed to have been

664
00:32:00,720 --> 00:32:04,600
Speaker 1: formed out of materials that were richer in carbon than

665
00:32:04,680 --> 00:32:07,440
Speaker 1: our solar system. So they think, Okay, that star has

666
00:32:07,480 --> 00:32:09,840
Speaker 1: a lot of carbon in it, Maybe the planet has

667
00:32:09,880 --> 00:32:12,160
Speaker 1: a lot of carbon also, maybe our assumption that this

668
00:32:12,240 --> 00:32:15,400
Speaker 1: planet was oxygen rich like the Earth was wrong. And

669
00:32:15,400 --> 00:32:17,480
Speaker 1: they said, well, what model could you build if you

670
00:32:17,480 --> 00:32:20,800
Speaker 1: started from carbon instead of from oxygen. I see, to

671
00:32:20,840 --> 00:32:24,080
Speaker 1: get the right sort of like size and mass, and

672
00:32:24,160 --> 00:32:26,280
Speaker 1: to make it sort of carbon ridge, you would have

673
00:32:26,320 --> 00:32:29,040
Speaker 1: to make the planet have a lot of carbon. Yeah,

674
00:32:29,440 --> 00:32:31,400
Speaker 1: so they said, well, maybe the planet is like one

675
00:32:31,480 --> 00:32:34,200
Speaker 1: third carbon, And then they started playing with models like

676
00:32:34,200 --> 00:32:36,520
Speaker 1: what would happen if you had a planet that was

677
00:32:36,560 --> 00:32:40,360
Speaker 1: one third carbon and this big right at this certain density.

678
00:32:40,520 --> 00:32:43,000
Speaker 1: They realized that would create an incredible pressure at its

679
00:32:43,040 --> 00:32:46,080
Speaker 1: core and that in some circumstances you would get an

680
00:32:46,200 --> 00:32:48,960
Speaker 1: enormous diamond, you know, like we're talking a diamond it's

681
00:32:49,040 --> 00:32:52,600
Speaker 1: like thousands of kilometers across because I guess you're assuming

682
00:32:52,640 --> 00:32:55,480
Speaker 1: all the carbon would sort default to the middle or

683
00:32:55,640 --> 00:32:57,400
Speaker 1: like it would push all the other stuff out as

684
00:32:57,440 --> 00:33:01,000
Speaker 1: it forms the diamond. And this incredible pressure, you know,

685
00:33:01,040 --> 00:33:03,760
Speaker 1: would essentially turn all of this carbon at the core

686
00:33:04,000 --> 00:33:07,040
Speaker 1: into a diamond. And obviously there would be impurities, right,

687
00:33:07,080 --> 00:33:09,720
Speaker 1: You'd have heavier metals like iron also, So wouldn't be

688
00:33:09,760 --> 00:33:14,120
Speaker 1: just like one pure perfect diamond, great triple A or anything,

689
00:33:14,400 --> 00:33:16,680
Speaker 1: but it would be like mostly diamond. Wow. And so

690
00:33:16,800 --> 00:33:19,040
Speaker 1: we're talking how big do you think this diamond is?

691
00:33:19,120 --> 00:33:22,560
Speaker 1: Like the size of Manhattan or the size of Australia.

692
00:33:22,600 --> 00:33:24,800
Speaker 1: How big do you think this diamond cores? You know,

693
00:33:24,840 --> 00:33:27,280
Speaker 1: this thing would be a third of the planet. So

694
00:33:27,520 --> 00:33:31,760
Speaker 1: it's huge. Yeah, I mean we're talking thousands of kilometers across. Wow,

695
00:33:31,960 --> 00:33:35,440
Speaker 1: Like bigger than the Moon, Bigger than much bigger, like

696
00:33:35,480 --> 00:33:37,840
Speaker 1: almost the size of Earth exactly. So what's kind of

697
00:33:37,880 --> 00:33:40,560
Speaker 1: ring would you need for a diamond bigger than the moon? Yeah,

698
00:33:40,680 --> 00:33:42,480
Speaker 1: so I guess if you like it, you better put

699
00:33:42,480 --> 00:33:49,400
Speaker 1: a rig on it, right exactly? There create a better

700
00:33:49,440 --> 00:33:52,040
Speaker 1: step up. All right, Well, thank you, Anthony. I that's

701
00:33:52,040 --> 00:33:54,120
Speaker 1: a great question, and I think that's the answer. We

702
00:33:54,240 --> 00:33:57,600
Speaker 1: think that this planet that's out there orbiting another star

703
00:33:58,040 --> 00:34:00,600
Speaker 1: has a lot of carbon in it. And if you

704
00:34:00,680 --> 00:34:02,960
Speaker 1: have that much carbon in a planet under that much

705
00:34:03,000 --> 00:34:06,760
Speaker 1: pressure inside it might form into a diamond. And so yes,

706
00:34:06,800 --> 00:34:09,400
Speaker 1: there might be a giant diamond inside of that planet.

707
00:34:09,560 --> 00:34:12,360
Speaker 1: That's right. But this, of course is all hypothetical. We

708
00:34:12,400 --> 00:34:14,680
Speaker 1: have a very few pieces of information. We're playing a

709
00:34:14,680 --> 00:34:17,319
Speaker 1: lot of games about what might be possible, and in

710
00:34:17,400 --> 00:34:19,600
Speaker 1: coming years we'll be able to image these planets and

711
00:34:19,640 --> 00:34:22,280
Speaker 1: see more about the light that's reflected from the surface

712
00:34:22,360 --> 00:34:25,080
Speaker 1: off of their stars and learning more about their atmospheres.

713
00:34:25,239 --> 00:34:27,920
Speaker 1: We'll get a lot more information about these planets, and

714
00:34:27,920 --> 00:34:30,480
Speaker 1: then we'll figure out what's out there, and probably what

715
00:34:30,520 --> 00:34:34,160
Speaker 1: we learned will be even more shocking than anything we hypothesized.

716
00:34:34,320 --> 00:34:36,880
Speaker 1: I guess the hard part would be mining this giant diamond, Like,

717
00:34:36,960 --> 00:34:39,080
Speaker 1: first of all, how do you like break it apart?

718
00:34:39,719 --> 00:34:41,080
Speaker 1: And the other part is how do you get it

719
00:34:41,080 --> 00:34:43,360
Speaker 1: out of the core of a giant planet? How do

720
00:34:43,360 --> 00:34:45,279
Speaker 1: you polish it right? You need to shine this thing

721
00:34:45,320 --> 00:34:47,920
Speaker 1: up if you're gonna sell it at market value. All right, well,

722
00:34:48,000 --> 00:34:50,480
Speaker 1: let's get into our last question from kids today, and

723
00:34:50,520 --> 00:34:53,600
Speaker 1: it's about the expanding the universe. But first let's take

724
00:34:53,600 --> 00:35:09,120
Speaker 1: another quick break. We are taking questions from kids today

725
00:35:09,239 --> 00:35:12,120
Speaker 1: and our last question comes from Addie, who is eight

726
00:35:12,200 --> 00:35:18,759
Speaker 1: years old. Hi, danieland my name is Abby and I

727
00:35:18,800 --> 00:35:22,920
Speaker 1: am eight years old. My question is, since the universe

728
00:35:23,040 --> 00:35:26,719
Speaker 1: is expanding faster than the speed of why can it

729
00:35:26,840 --> 00:35:31,480
Speaker 1: go back in time? Thank you? WHOA. This question just

730
00:35:31,480 --> 00:35:37,520
Speaker 1: blew my mind. Can the universe itself be traveling back

731
00:35:37,560 --> 00:35:39,200
Speaker 1: in time? That's crazy? But first, of all, I have

732
00:35:39,200 --> 00:35:42,000
Speaker 1: a question for you, Daniel, why do kids always identify

733
00:35:42,040 --> 00:35:44,360
Speaker 1: their age? Like, at what point do we as adults

734
00:35:44,360 --> 00:35:46,279
Speaker 1: stop saying how old we are? I think the point

735
00:35:46,280 --> 00:35:49,280
Speaker 1: where we stop remembering how old we are. I introduced

736
00:35:49,320 --> 00:35:50,879
Speaker 1: myself and I'm like, oh, I'm forty four. My kids

737
00:35:50,920 --> 00:35:56,319
Speaker 1: are like, no, you're forty six, dude. Yeah. Yeah, but

738
00:35:56,360 --> 00:35:58,200
Speaker 1: it's great to know. Thank you, Addie. This is a

739
00:35:58,280 --> 00:36:01,000
Speaker 1: great question. I think Audi is putting a couple of

740
00:36:01,040 --> 00:36:03,600
Speaker 1: ideas here together, right, Like we know, and we've talked

741
00:36:03,600 --> 00:36:06,799
Speaker 1: about the idea that the universe is expanding, and it's

742
00:36:06,840 --> 00:36:09,560
Speaker 1: expanding at its edges, or at least as far as

743
00:36:09,800 --> 00:36:12,960
Speaker 1: the furthest from us as you can faster than the

744
00:36:12,960 --> 00:36:15,840
Speaker 1: speed of light. And we've also talked about how like,

745
00:36:15,920 --> 00:36:17,799
Speaker 1: nothing can move this faster than the speed of light,

746
00:36:17,960 --> 00:36:19,399
Speaker 1: but if it does, it would mean it would sort

747
00:36:19,400 --> 00:36:21,680
Speaker 1: of go back in time or break the rules of time. Yeah,

748
00:36:21,680 --> 00:36:23,960
Speaker 1: these are two really fun ideas, and I love hearing

749
00:36:24,000 --> 00:36:26,520
Speaker 1: kids put these ideas together and your first you're like, no,

750
00:36:26,640 --> 00:36:28,879
Speaker 1: that's crazy, and you know, hold on a second, Maybe

751
00:36:28,920 --> 00:36:31,920
Speaker 1: that's a good point. Maybe he's right, maybe going back right,

752
00:36:31,960 --> 00:36:34,680
Speaker 1: it's not just kids I'm like, yeah, yeah, what's the

753
00:36:34,680 --> 00:36:37,160
Speaker 1: answer here is the edge of the universe going back

754
00:36:37,200 --> 00:36:40,040
Speaker 1: in time. It's a great question, and you know, he's

755
00:36:40,200 --> 00:36:43,600
Speaker 1: right that the universe is expanding faster than the speed

756
00:36:43,640 --> 00:36:47,000
Speaker 1: of light. But there's some important subtleties there, right, like

757
00:36:47,320 --> 00:36:51,040
Speaker 1: what is happening. It's not that things are flying out

758
00:36:51,080 --> 00:36:54,520
Speaker 1: through the universe and that they're traveling relative to each

759
00:36:54,600 --> 00:36:56,960
Speaker 1: other faster than the speed of light. You know, like

760
00:36:57,120 --> 00:37:00,279
Speaker 1: no object is looking at another object and saying your

761
00:37:00,360 --> 00:37:03,440
Speaker 1: velocity is greater than the speed of light. However, that

762
00:37:03,520 --> 00:37:07,280
Speaker 1: doesn't mean that distances can't increase faster than the speed

763
00:37:07,320 --> 00:37:10,080
Speaker 1: of light. Right, It all depends on sort of who's

764
00:37:10,120 --> 00:37:12,960
Speaker 1: asking the question. It's like, nobody is moving faster than

765
00:37:12,960 --> 00:37:15,960
Speaker 1: the speed of light, but things are. The space itself

766
00:37:16,040 --> 00:37:19,520
Speaker 1: is growing faster than the speed of light overall. That's right,

767
00:37:19,560 --> 00:37:24,000
Speaker 1: because new space is being created between galaxies, new spaces

768
00:37:24,040 --> 00:37:27,160
Speaker 1: being created, and there's no limit to how fast space

769
00:37:27,200 --> 00:37:29,480
Speaker 1: can be created. And you might ask, like a hold

770
00:37:29,520 --> 00:37:31,680
Speaker 1: on a second, who's creating new space and how does

771
00:37:31,719 --> 00:37:34,000
Speaker 1: it work? And surely there's somebody in charge of it

772
00:37:34,040 --> 00:37:36,200
Speaker 1: and there's limits, right, we don't know. The answer is

773
00:37:36,200 --> 00:37:38,880
Speaker 1: to any of those questions. We just see that space

774
00:37:39,080 --> 00:37:41,680
Speaker 1: is expanding. This is what we call dark energy, and

775
00:37:41,719 --> 00:37:45,080
Speaker 1: so we know that something out there is capable of

776
00:37:45,080 --> 00:37:49,480
Speaker 1: expanding the universe itself, of stretching space or making new space,

777
00:37:49,480 --> 00:37:53,400
Speaker 1: and that's happening everywhere Isotropically, the whole universe is expanding,

778
00:37:53,520 --> 00:37:56,480
Speaker 1: but it only happens a little bit over a short distance.

779
00:37:57,080 --> 00:37:59,640
Speaker 1: So between me and you, for example, wherever you are

780
00:37:59,640 --> 00:38:02,120
Speaker 1: in the Earth Earth, space is expanding a very very

781
00:38:02,160 --> 00:38:04,680
Speaker 1: tiny bit every year, but you know, the Earth holds

782
00:38:04,719 --> 00:38:07,520
Speaker 1: us together. Between us and the Sun, space is expanding

783
00:38:07,560 --> 00:38:10,240
Speaker 1: a little bit more every year, but the Sun holds

784
00:38:10,280 --> 00:38:13,200
Speaker 1: us together. But between us and other galaxies, there's a

785
00:38:13,239 --> 00:38:15,479
Speaker 1: lot of space there. So all the new little bits

786
00:38:15,480 --> 00:38:18,560
Speaker 1: of space add up and it becomes pretty significant. And

787
00:38:18,600 --> 00:38:21,520
Speaker 1: across the whole universe is huge amounts of space. So

788
00:38:21,520 --> 00:38:24,160
Speaker 1: you're add up all of those expansions and you actually

789
00:38:24,239 --> 00:38:26,960
Speaker 1: do get speeds that exceed the speed of light. It's

790
00:38:27,000 --> 00:38:28,960
Speaker 1: kind of like maybe for audi here it's almost like

791
00:38:29,000 --> 00:38:30,960
Speaker 1: you can't run faster than the speed of light in

792
00:38:31,000 --> 00:38:34,680
Speaker 1: your house, but your house is sort of growing a

793
00:38:34,719 --> 00:38:36,600
Speaker 1: little bit. So you stand on one end of the

794
00:38:36,640 --> 00:38:38,800
Speaker 1: house and you look at the other end of the house,

795
00:38:38,840 --> 00:38:40,799
Speaker 1: at the on the other side, you would see it

796
00:38:40,920 --> 00:38:45,520
Speaker 1: sort of growing faster than like could move. That's exactly right,

797
00:38:45,880 --> 00:38:48,360
Speaker 1: And so we can measure the distances to things we

798
00:38:48,400 --> 00:38:50,840
Speaker 1: see that those velocities do seem to add up to

799
00:38:50,840 --> 00:38:52,560
Speaker 1: be greater than the speed of light. But you know,

800
00:38:52,600 --> 00:38:54,920
Speaker 1: if you looked at any one thing and you asked,

801
00:38:54,920 --> 00:38:57,520
Speaker 1: how fast is this one thing moving relative to me,

802
00:38:57,880 --> 00:39:00,880
Speaker 1: you would never measure a velocity greater than the speed

803
00:39:00,880 --> 00:39:04,080
Speaker 1: of light, because remember, you can't measure velocity relative to space.

804
00:39:04,440 --> 00:39:06,960
Speaker 1: Space doesn't have like a reference frame. There's no absolute

805
00:39:07,000 --> 00:39:10,280
Speaker 1: frame there. You can only measure velocities relative to an object.

806
00:39:10,480 --> 00:39:13,799
Speaker 1: All right, So then the universe is expanding faster than

807
00:39:13,920 --> 00:39:17,359
Speaker 1: light can travel, but nothing is actually moving faster than light.

808
00:39:17,560 --> 00:39:19,600
Speaker 1: And so the other idea they put together is this

809
00:39:19,680 --> 00:39:22,560
Speaker 1: idea that going faster than light somehow breaks time or

810
00:39:22,640 --> 00:39:24,799
Speaker 1: makes you go backwards in time. Yeah, that's a really

811
00:39:24,840 --> 00:39:28,040
Speaker 1: fun conclusion, and it's sort of meant to tell you

812
00:39:28,080 --> 00:39:30,279
Speaker 1: that you can't go faster than the speed of light.

813
00:39:30,600 --> 00:39:33,279
Speaker 1: You know, we have these ideas of how the universe works,

814
00:39:33,360 --> 00:39:36,880
Speaker 1: of how information can propagate, and how there's a maximum

815
00:39:36,920 --> 00:39:39,839
Speaker 1: speed of information, that no information can move faster than

816
00:39:39,880 --> 00:39:43,040
Speaker 1: the speed of light. No object, and no information, no particle,

817
00:39:43,400 --> 00:39:45,640
Speaker 1: no wave can ripple faster than the speed of light.

818
00:39:45,840 --> 00:39:48,120
Speaker 1: And what happens if you ask, like, well, what happens

819
00:39:48,160 --> 00:39:51,319
Speaker 1: if an object does move faster than the speed of light, Well,

820
00:39:51,360 --> 00:39:53,640
Speaker 1: then you get a paradox, You get contradictions. You get

821
00:39:53,640 --> 00:39:55,960
Speaker 1: things like, well, if it could move fast in the

822
00:39:56,000 --> 00:39:58,520
Speaker 1: speed of light, that would be equivalent to it moving

823
00:39:58,560 --> 00:40:01,160
Speaker 1: backwards in time, which we know to be impossible. And

824
00:40:01,239 --> 00:40:03,240
Speaker 1: so it's sort of just like another way of saying

825
00:40:03,239 --> 00:40:05,319
Speaker 1: that you can't move fast in the speed of light.

826
00:40:05,440 --> 00:40:07,719
Speaker 1: Sometimes people interpret this saying like, oh, if you want

827
00:40:07,719 --> 00:40:09,600
Speaker 1: to go backwards in time, all you gotta do is

828
00:40:09,640 --> 00:40:11,399
Speaker 1: go fast in the speed of light. But it's sort

829
00:40:11,400 --> 00:40:14,640
Speaker 1: of like saying no, that's impossible, right, like Superman and Superman.

830
00:40:15,680 --> 00:40:17,520
Speaker 1: But I guess maybe I'm wondering if it's maybe a

831
00:40:17,600 --> 00:40:19,480
Speaker 1: little bit of a circular argument, Like you're sort of

832
00:40:19,480 --> 00:40:21,640
Speaker 1: assuming you can't go it faster than the speed of light,

833
00:40:21,760 --> 00:40:23,520
Speaker 1: and then you say, but if you can, then it

834
00:40:23,520 --> 00:40:26,040
Speaker 1: would break the rules. It's almost like you make an

835
00:40:26,040 --> 00:40:28,160
Speaker 1: assumption and then you say, if you break the assumption,

836
00:40:28,280 --> 00:40:31,000
Speaker 1: then it doesn't work. Yeah, absolutely, And you're right, And

837
00:40:31,320 --> 00:40:33,719
Speaker 1: we don't understand this limit at all. You know, we

838
00:40:33,800 --> 00:40:36,960
Speaker 1: observe this limit. We say the speed of light is constant.

839
00:40:37,280 --> 00:40:40,400
Speaker 1: It doesn't depend on who is sending the message or

840
00:40:40,480 --> 00:40:42,920
Speaker 1: their velocity. It's always the same speed. And if you

841
00:40:42,960 --> 00:40:45,400
Speaker 1: start from that, then you get to consequences like you

842
00:40:45,440 --> 00:40:47,520
Speaker 1: can't move faster than the speed of light, and all

843
00:40:47,520 --> 00:40:50,040
Speaker 1: sorts of things about how time varies, all of special

844
00:40:50,040 --> 00:40:52,759
Speaker 1: relativity is based on that one observation. We don't know

845
00:40:52,800 --> 00:40:56,279
Speaker 1: why that thing is true, but everything flows from that

846
00:40:56,320 --> 00:40:59,200
Speaker 1: thing that the speed of light is constant for all observers,

847
00:40:59,640 --> 00:41:02,839
Speaker 1: and so that's what limits you to going faster than

848
00:41:02,840 --> 00:41:04,600
Speaker 1: the speed of light. And so you're right. If we

849
00:41:04,640 --> 00:41:07,120
Speaker 1: observe the scenario in which that wasn't true anymore, then

850
00:41:07,200 --> 00:41:09,560
Speaker 1: maybe you would, you know, change all these other rules,

851
00:41:09,640 --> 00:41:12,000
Speaker 1: or maybe that's wrong and we just don't understand. So

852
00:41:12,040 --> 00:41:13,800
Speaker 1: if you see somebody going fast in the speed of

853
00:41:13,880 --> 00:41:17,319
Speaker 1: light or going backwards in time, that suggests that the

854
00:41:17,360 --> 00:41:21,000
Speaker 1: speed of light is not constant for all observers. Interesting,

855
00:41:21,080 --> 00:41:22,759
Speaker 1: I see. It's like from what we can see about

856
00:41:22,760 --> 00:41:25,200
Speaker 1: the universe, we came up with the speed limit of

857
00:41:25,200 --> 00:41:28,680
Speaker 1: the universe, and then breaking that speed limit suddenly breaks

858
00:41:28,719 --> 00:41:31,319
Speaker 1: everything we know about time and everything else. But it is,

859
00:41:31,360 --> 00:41:33,640
Speaker 1: I guess, technically possible that you could would like go

860
00:41:33,760 --> 00:41:36,400
Speaker 1: faster than light. It's technically possible in the sense that,

861
00:41:36,440 --> 00:41:38,600
Speaker 1: you know, we've never observed it, and everything we have

862
00:41:38,719 --> 00:41:41,960
Speaker 1: observed suggests that it is impossible. But you know, that's

863
00:41:41,960 --> 00:41:44,799
Speaker 1: just physics. These are theories. We make an observation here,

864
00:41:44,840 --> 00:41:47,719
Speaker 1: we infer about the universe. From it, we draw conclusions.

865
00:41:47,800 --> 00:41:50,360
Speaker 1: If those conclusions are wrong, then either our inference was

866
00:41:50,400 --> 00:41:53,279
Speaker 1: wrong or the observations we made were wrong, And hey,

867
00:41:53,360 --> 00:41:55,880
Speaker 1: that would be awesome because that would be you know,

868
00:41:56,000 --> 00:41:59,279
Speaker 1: a childlike dream to overthrow something so basic. Is like

869
00:41:59,400 --> 00:42:01,319
Speaker 1: the fact that the speed of light is the same

870
00:42:01,360 --> 00:42:03,640
Speaker 1: as measured by everybody. But you know, it's something it's

871
00:42:03,640 --> 00:42:05,840
Speaker 1: experiments we've been doing for more than a hundred years,

872
00:42:05,880 --> 00:42:09,040
Speaker 1: and we've seen it very concretely and very stable for

873
00:42:09,080 --> 00:42:12,359
Speaker 1: a long time. So we're pretty confident in this observation

874
00:42:12,760 --> 00:42:14,480
Speaker 1: that the speed of light is always the same no

875
00:42:14,560 --> 00:42:16,920
Speaker 1: matter who measures it, and the implication of that that

876
00:42:16,960 --> 00:42:18,680
Speaker 1: it means that you can't go faster than the speed

877
00:42:18,680 --> 00:42:21,120
Speaker 1: of light is also pretty solid, so I think it's

878
00:42:21,120 --> 00:42:24,279
Speaker 1: pretty air tight. But yeah, we have made mistakes before, right,

879
00:42:24,360 --> 00:42:27,319
Speaker 1: And so where there's this idea that going faster than

880
00:42:27,360 --> 00:42:30,879
Speaker 1: the speed of light would make time go backwards somehow, Well,

881
00:42:30,920 --> 00:42:33,759
Speaker 1: it comes from the idea that time is sort of fungible,

882
00:42:33,800 --> 00:42:36,680
Speaker 1: that like the order of events that happen depends on

883
00:42:36,760 --> 00:42:39,600
Speaker 1: your speed. Like if you're watching two things happen, like

884
00:42:39,640 --> 00:42:42,600
Speaker 1: Alice eats a pie and then Bob eats a pie,

885
00:42:43,000 --> 00:42:45,160
Speaker 1: and you're sitting there with them and you're watching, maybe

886
00:42:45,160 --> 00:42:47,960
Speaker 1: you think Alice finishes first. But if I'm going at

887
00:42:47,960 --> 00:42:51,080
Speaker 1: really high speed, I can find some scenario in which

888
00:42:51,160 --> 00:42:54,080
Speaker 1: I see the order of events happening differently. Right, So,

889
00:42:54,160 --> 00:42:57,960
Speaker 1: like Alice finishing before Bob is not like a universal truth.

890
00:42:58,040 --> 00:43:00,799
Speaker 1: It depends on who's asking and how fast they're going.

891
00:43:01,560 --> 00:43:03,920
Speaker 1: And so this idea that you know you can change

892
00:43:03,960 --> 00:43:07,480
Speaker 1: the order of events depends on your velocity tells you

893
00:43:07,520 --> 00:43:09,719
Speaker 1: that you can sort of play with time, and that

894
00:43:09,840 --> 00:43:13,279
Speaker 1: the velocity and time are connected. But it's not necessarily

895
00:43:13,280 --> 00:43:15,440
Speaker 1: the case that if you are going faster than the

896
00:43:15,480 --> 00:43:18,000
Speaker 1: speed flight. Let's say it was possible that some out

897
00:43:18,040 --> 00:43:22,400
Speaker 1: time would flow backwards or like your clocks would certainly

898
00:43:22,440 --> 00:43:24,240
Speaker 1: start going the other way, or you know, you would

899
00:43:24,440 --> 00:43:27,520
Speaker 1: travel to a different time. And that's sort of so

900
00:43:27,640 --> 00:43:30,440
Speaker 1: far kind of not really establishing the math. Well, what

901
00:43:30,520 --> 00:43:32,640
Speaker 1: the math suggests is that if you go faster than

902
00:43:32,640 --> 00:43:35,080
Speaker 1: the speed of light, then you can invert the order

903
00:43:35,120 --> 00:43:37,279
Speaker 1: of things that you otherwise shouldn't be able to, Like

904
00:43:37,400 --> 00:43:40,480
Speaker 1: you can switch who wins the pie eating contest, Alice

905
00:43:40,560 --> 00:43:42,719
Speaker 1: or Bob by going faster or slower, going in some

906
00:43:42,800 --> 00:43:45,919
Speaker 1: direction because those things aren't like caustically connected, doesn't really

907
00:43:45,960 --> 00:43:48,319
Speaker 1: matter which one happens first. But if you go faster

908
00:43:48,360 --> 00:43:50,400
Speaker 1: than the speed of light, then you might see weird

909
00:43:50,440 --> 00:43:53,520
Speaker 1: things like Alice arrives in the pie eating contest before

910
00:43:53,600 --> 00:43:56,279
Speaker 1: she leaves her house. You know, you can switch the

911
00:43:56,400 --> 00:43:59,200
Speaker 1: order of things so they're like reversed in time. So

912
00:43:59,239 --> 00:44:01,759
Speaker 1: in that sense, you're sort of like going backwards. You

913
00:44:01,800 --> 00:44:05,399
Speaker 1: would maybe experience things backwards, is what you're saying, which

914
00:44:05,440 --> 00:44:07,600
Speaker 1: is sort of like and if the whole universe is

915
00:44:07,800 --> 00:44:09,719
Speaker 1: going backwards, and it's sort of like you're going back

916
00:44:09,760 --> 00:44:11,759
Speaker 1: in time, is what you're saying. And we have a

917
00:44:11,760 --> 00:44:15,920
Speaker 1: whole interesting episode about this theoretical particle called a tachion,

918
00:44:16,320 --> 00:44:18,560
Speaker 1: which in principle moves faster than the speed of light.

919
00:44:18,840 --> 00:44:20,719
Speaker 1: But you know, if it exists, it would break all

920
00:44:20,719 --> 00:44:23,680
Speaker 1: sorts of special relativity, but has really weird properties, like

921
00:44:24,080 --> 00:44:26,840
Speaker 1: you see it as if it's leaving, even if it's arriving,

922
00:44:27,120 --> 00:44:30,480
Speaker 1: because the later light arrives first, because it's moving faster

923
00:44:30,560 --> 00:44:33,759
Speaker 1: than light. I see. So if this particle is really

924
00:44:33,760 --> 00:44:37,400
Speaker 1: would be very tacky. It would be breaking everything in

925
00:44:37,440 --> 00:44:39,879
Speaker 1: the universe, and that's just not cool. That's right. You'd

926
00:44:39,880 --> 00:44:41,600
Speaker 1: invited your birthday party and it would look like it's

927
00:44:41,640 --> 00:44:44,080
Speaker 1: leaving your birthday party, and you're like, hey man, yeah,

928
00:44:44,440 --> 00:44:47,480
Speaker 1: hey man. All right. Well it's a great question from Audi,

929
00:44:47,600 --> 00:44:50,000
Speaker 1: is if the universe expanding faster than light, can I

930
00:44:50,080 --> 00:44:53,040
Speaker 1: go back in time? And the answer is kind of

931
00:44:53,200 --> 00:44:56,600
Speaker 1: yes and no, Like, yes, the universe is expanding faster

932
00:44:56,719 --> 00:44:58,759
Speaker 1: than light, but for you to sort of break the

933
00:44:58,840 --> 00:45:01,640
Speaker 1: laws of time, you kind of have to travel faster

934
00:45:01,680 --> 00:45:03,640
Speaker 1: than light, which is not what the universe is doing.

935
00:45:03,680 --> 00:45:06,040
Speaker 1: The universe is expanding faster than light, but it's not

936
00:45:06,160 --> 00:45:09,040
Speaker 1: traveling faster than light. That's right. Nothing is moving faster

937
00:45:09,120 --> 00:45:12,120
Speaker 1: than light relative to any other thing, and so that

938
00:45:12,160 --> 00:45:15,080
Speaker 1: doesn't break the laws of special relativity. Well, things are

939
00:45:15,239 --> 00:45:17,840
Speaker 1: growing in distance from one edge of the universe to

940
00:45:17,880 --> 00:45:20,239
Speaker 1: the other. It's faster than light, but nothing's actually you

941
00:45:20,280 --> 00:45:23,640
Speaker 1: could say, is traveling through that space faster than than light? Yeah,

942
00:45:23,680 --> 00:45:26,840
Speaker 1: that's right, all right. Well those were three awesome questions

943
00:45:26,920 --> 00:45:29,440
Speaker 1: from kids. Thank you kids for sending in your questions,

944
00:45:29,600 --> 00:45:32,120
Speaker 1: and thank you parents for encouraging your kids to think

945
00:45:32,120 --> 00:45:35,120
Speaker 1: about the universe and ask the deep questions, because it's

946
00:45:35,160 --> 00:45:37,120
Speaker 1: those kids that we hope are going to one day

947
00:45:37,160 --> 00:45:39,799
Speaker 1: figure out the answers to these questions. They're not so

948
00:45:40,080 --> 00:45:43,359
Speaker 1: entrenched in today's ideas about how the universe work, and

949
00:45:43,400 --> 00:45:45,920
Speaker 1: they might have crazy new ideas about how to use

950
00:45:46,040 --> 00:45:48,920
Speaker 1: lightsabers to cut open black holes and solve the mysteries

951
00:45:48,920 --> 00:45:50,759
Speaker 1: of quantum gravity. I don't think we need to think

952
00:45:50,760 --> 00:45:54,000
Speaker 1: the parents, Daniel. Everyone knows it's a thankless job you

953
00:45:54,080 --> 00:45:58,400
Speaker 1: don't really get. But thank you to all of our listeners,

954
00:45:58,440 --> 00:46:00,720
Speaker 1: young and old for having question us about the universe.

955
00:46:00,760 --> 00:46:05,040
Speaker 1: I've been curious for wandering about this amazing and mysterious

956
00:46:05,160 --> 00:46:07,400
Speaker 1: cosmos that we live in. And if you have questions,

957
00:46:07,800 --> 00:46:10,000
Speaker 1: please feel free to send them to us. We hope

958
00:46:10,040 --> 00:46:13,440
Speaker 1: you enjoyed that. Thanks for listening, See you next time.

959
00:46:21,239 --> 00:46:24,080
Speaker 1: Thanks for listening, and remember that Daniel and Jorge explained.

960
00:46:24,080 --> 00:46:26,960
Speaker 1: The Universe is a production of I heart Radio. For

961
00:46:27,120 --> 00:46:30,040
Speaker 1: more podcast for my heart Radio, visit the i heart

962
00:46:30,120 --> 00:46:33,719
Speaker 1: Radio app, Apple Podcasts, or wherever you listen to your

963
00:46:33,760 --> 00:46:40,120
Speaker 1: favorite shows. Ye