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Speaker 1: The message you often hear about space is that it's

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Speaker 1: vast and empty. The Earth and even the Sun are

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Speaker 1: these tiny dots and a huge ocean of black space.

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Speaker 1: That's all true, but it gives you the wrong idea

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Speaker 1: about our cosmic neighborhood. It suggests that the Earth is isolated, alone,

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Speaker 1: not affected by our neighbors, not in danger. The truth

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Speaker 1: is actually the opposite. Space is vast, but gravity is

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Speaker 1: also very patient. There are a lot of big dark

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Speaker 1: rocks out there that could get tugged by gravity towards

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Speaker 1: the Earth and then dramatically affect our way of life,

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Speaker 1: both positively or negatively. They could, of course smash into

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Speaker 1: us and cause an extinction event, but then they could

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Speaker 1: also create new snazzy bling around our planet. So today

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Speaker 1: we're going to dig deep into the history of Earth

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Speaker 1: within our cosmic neighborhood, understand the gravitational dance between all

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Speaker 1: of these objects, and ask the question about whether there

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Speaker 1: was ever a time when the universe put a ring

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Speaker 1: on the Earth. So, just in time for Valentine's Day,

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Speaker 1: we're getting cosmically romantic and asking did Earth ever have

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Speaker 1: a ring? Welcome to Daniel and Kelly's extraordinary universe. Hello.

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Speaker 2: I'm Kelly Wienersmith. I'm a parasitologist and I stopped wearing

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Speaker 2: rings because I got fish guts stuck in my ring

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Speaker 2: too many times and decided it was too gross.

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Speaker 1: Oh isn't that romantic though?

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Speaker 2: Fish guts in a ring? You got a weird sense

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Speaker 2: of romance, Daniel, I'm.

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Speaker 1: Trying to resonate with a biology. Hi. I'm Daniel. I'm

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Speaker 1: a particle physicist, and I bought my wedding rings for

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Speaker 1: two dollars on Telegraph Avenue in Berkeley.

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Speaker 2: I was going to ask you, are you and Katrina

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Speaker 2: ring people or not ring people?

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Speaker 1: We have rings which we feel sentimental about, but we're

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Speaker 1: not people who are into expensive fancy stuff. So like

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Speaker 1: her engagement ring has a piece of amber in it,

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Speaker 1: and I designed the ring myself. There's no like crazy

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Speaker 1: diamond in there. And we didn't want to spend a

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Speaker 1: lot of money on crazy rings, so we just walked

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Speaker 1: down Telegraph Avenue and found a guy who made silver

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Speaker 1: rings and bottom for a couple of bucks.

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Speaker 2: You designed a ring with amber and got it for

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Speaker 2: two bucks.

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Speaker 1: Oh no, the engagement ring I had a friend make,

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Speaker 1: so that was more than two dollars, but yes, I

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Speaker 1: designed it myself. It has a bunch of Danish ruins

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Speaker 1: in it and stuff and a piece of amber in

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Speaker 1: the middle.

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Speaker 2: Oh that's great.

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Speaker 1: How about you? What's your guys ring story?

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Speaker 2: Can I tell you our engagement story really quick? Oh?

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Speaker 1: Yes? Does it involve fish cuts? No?

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Speaker 2: No, the rest of our life involves fish cuts, but no,

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Speaker 2: our engagement story. So Zach is like not a super

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Speaker 2: sentimental guy, and so, like, a couple months earlier, I

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Speaker 2: had said to him, like, hey, you know we've been

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Speaker 2: together for a year, do you think you could ever

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Speaker 2: see yourself marrying me? Because if still, let's keep going.

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Speaker 2: But if not, let's like cut our losses and bee

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Speaker 2: like this was fun. And so his response, and this

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Speaker 2: is amazing. His response was I think you're really nice, wow,

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Speaker 2: which I thought was him being like I don't want

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Speaker 2: to answer this question because it's going to be uncomfortable,

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Speaker 2: but like, that's not what I was looking for, right,

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Speaker 2: And so I thought to myself, like, Okay, in a

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Speaker 2: couple more months, I'm going to ask him this again,

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Speaker 2: and if I don't get a better answer, it's over.

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Speaker 2: But so Zach thought, well, you marry the person who

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Speaker 2: you think is really nice. So he thought he had

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Speaker 2: said like, yeah, I could marry you one day, and

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Speaker 2: he thought after that conversation that it was locked in

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Speaker 2: and that he didn't even really need to ask.

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Speaker 1: That was like the most positive thing he could think

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Speaker 1: of saying, I think you're really nice.

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Speaker 2: No, he's not a super sentimental side. So it was

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Speaker 2: Pie Day, March fourteenth, and he gave me a little

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Speaker 2: card with a pie on it that said don't open

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Speaker 2: until what are the extended digits of pie? So three

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Speaker 2: fourteen is the date, and then it's nine okay, yeah,

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Speaker 2: so don't open until one fifty nine. And I thought

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Speaker 2: it was going to be a poem about how like

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Speaker 2: I eat too much pie he writes like weird poems,

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Speaker 2: and I forgot about it, and so later in the day,

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Speaker 2: it was like four pm and he was in the

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Speaker 2: restroom and I reached into my pocket and I was like, oh,

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Speaker 2: I've got this card in my pocket and it's after

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Speaker 2: one fifty nine, so I can open it. And it

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Speaker 2: said something to the effect of, like, you get frustrated

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Speaker 2: because I forgot our anniversary. But if we got engaged

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Speaker 2: on Pie Day, that's a date I'd always remember.

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Speaker 1: Oh my gosh.

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Speaker 2: And so he came out of the bathroom and I

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Speaker 2: was like, are you asking me to marry you? And

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Speaker 2: so I'll note that he forgot when one fifty nine passed,

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Speaker 2: so he wasn't worried about the answer. He knew what

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Speaker 2: the answer was gonna be.

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Speaker 1: And I love that there's a bathroom visit in the

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Speaker 1: middle of this story. That's very Kelly and Zach.

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Speaker 2: Exactly, very scatological. And so I was like, wait, so

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Speaker 2: are we engaged now? And all he said was, well,

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Speaker 2: you weren't supposed to read it while I was on

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Speaker 2: the hut. Anyway, he didn't have a ring, he didn't

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Speaker 2: have anything. We're not very sentimental. So anyway, we went out.

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Speaker 2: We got a ring. I got fish guts in it,

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Speaker 2: so I stopped wearing it because while I was doing dissections,

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Speaker 2: it kept getting in the way. I got him a ring,

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Speaker 2: and when we were walking around Rice University, our daughter

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Speaker 2: was playing with it, and I was like, Zach, and

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Speaker 2: she was like two as like, Zach, she's gonna drop it.

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Speaker 2: You're gonna lose your wedding ring. You probably shouldn't let

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Speaker 2: her play with it. And we got back into the

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Speaker 2: car and he sat down and he goes, uh oh.

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Speaker 2: And anyway, so he lost his ring, and I don't

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Speaker 2: wear mine because of fish guts and we are not

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Speaker 2: super sentimental. But you know, it's been almost twenty years

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Speaker 2: since we've been together, so it's working out.

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Speaker 1: So Zach's ring is somewhere on the campus of Rice University, or.

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Speaker 2: Some undergrad plays drinking games with it or something. I

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Speaker 2: don't know. I don't know where it ended up. We

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Speaker 2: never found it.

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Speaker 1: All right, Rice students, if you see a ring on campus,

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Speaker 1: send it to Kelly.

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Speaker 2: Yeah, I'll take all the random rings that get lost

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Speaker 2: on campus. All right, Well, I've gotten us off topic.

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Speaker 2: Your story was lovely. Mine was hopefully good for a laugh.

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Speaker 2: But today we're talking about whether or not Earth ever

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Speaker 2: had a ring, which is a fun question to think about.

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Speaker 1: It's fun to think about because it makes us think

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Speaker 1: about the deep past and how we think of the

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Speaker 1: Earth as a certain way and having the moon and

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Speaker 1: the sky looks a certain way and the solar systems

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Speaker 1: arranged a certain way, and we imagine it's always been

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Speaker 1: that way or forzillions of years. But it turns out

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Speaker 1: that on a cosmic time scale, the solar system has

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Speaker 1: a very chaotic history, and things used to look quite

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Speaker 1: a bit different. So it's really fun for me to

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Speaker 1: go deep into the past and learn about how the

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Speaker 1: Solar system used to be quite different, how life on

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Speaker 1: Earth could have been different. You could have looked up

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Speaker 1: at the sky and seeing different stuff out there.

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Speaker 2: And I got to say, when you sent me this

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Speaker 2: idea for a podcast episode topic, it had not been

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Speaker 2: on my radar at all that Earth could have ever

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Speaker 2: had a ring. So I'm excited about hearing the answer

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Speaker 2: to this.

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Speaker 1: So I was wondering if folks out there had considered

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Speaker 1: the possibility of whether Earth had ever had a ring.

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Speaker 1: So I sent this question to our intrepid volunteers. Thank

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Speaker 1: you very much to everybody who plays along. If you

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Speaker 1: would like to hear your voice answering questions on the podcast,

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Speaker 1: please don't be shy. We would love to have you

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Speaker 1: as part of the chorus. To us two questions at

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Speaker 1: Danielankelly dot org and we will set you up in

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Speaker 1: the meantime. Think about it for a minute. Do you

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Speaker 1: think Earth could have ever had a ring? Here's what

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Speaker 1: our listeners had to say. A big meteorite smashed into

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Speaker 1: the Earth all the debris shot up into the into space.

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Speaker 1: The Earth did have a ring with the material that

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Speaker 1: eventually call us into the Moon.

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Speaker 2: Yes, it did have a ring, and it still does.

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Speaker 3: Maybe it did, like with all the rocks flying around

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Speaker 3: it right at the beginning when it was being formed,

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Speaker 3: had like a wriggled rocks around it. And maybe when

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Speaker 3: the ice it happens and been a thing of vice

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Speaker 3: around it when there was the ice. Say, I don't

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Speaker 3: really think that could have happened.

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Speaker 2: So, yes, the Earth probably had a ring when the

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Speaker 2: Moon was born. As bodies coal started to fall into

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Speaker 2: planet olids and eventually planets that would have been rings.

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Speaker 1: Earth might have had a ring after the collision with Theata.

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Speaker 1: If you're referring to a persistent ring system akin to Saturns,

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Speaker 1: then that's more of a complex question open to interpretation.

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Speaker 1: The ejecta from that collision temporarily formed a ring.

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Speaker 2: There is a chance that's to be some sort of

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Speaker 2: ring during its creation.

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Speaker 1: It no longer has a ring because it is divorced.

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Speaker 1: Middle Earth did and it was a big freaking deal.

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Speaker 1: Is that one of the theories or hypotheses behind where

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Speaker 1: the Moon came from.

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Speaker 2: When a Mars sized object collided with Earth. Do Bear's

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Speaker 2: poop in the woods?

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Speaker 1: Do taco taste better on Tuesdays?

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Speaker 2: Does Tom Cruise will have to sprint like a maniac

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Speaker 2: in every one of his movies? Yes, yes, the Earth

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Speaker 2: had a ring, but.

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Speaker 1: I'll do notize that Liberachi had rings during the formation

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Speaker 1: of the Moon.

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Speaker 2: No, I mean Saturn offered, but long distance relationships just

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Speaker 2: never work out.

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Speaker 1: And a protope planet hits it to form the Moon.

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Speaker 2: While the moon was being formed.

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Speaker 1: I really don't know, but I imagine not since the

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Speaker 1: moon has been there.

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Speaker 2: That was an amazing mix of like serious good answers

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Speaker 2: and some really clever not answers.

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Speaker 1: I think Tom Cruise does sprint in every movie he's in.

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Speaker 1: I think that's true every.

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Speaker 2: Movie I can think of. Did he sprint in Jerry Maguire,

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Speaker 2: He must have. There must have been a reason to sprint.

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Speaker 2: Somebody check the footage, Okay, let us know.

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Speaker 1: And I was a little surprised, though I guess I

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Speaker 1: shouldn't have been that most people went to the sort

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Speaker 1: of early formation of the Earth, the impact with the

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Speaker 1: protoplanet that formed the Moon, and thinking about how that

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Speaker 1: might have been a ring as well, and that's a

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Speaker 1: totally reasonable answer. That it's not what I was going

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Speaker 1: for for today's episode.

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Speaker 2: Well, I think probably it would help to know how

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Speaker 2: rings are formed in general. So I'm guessing you're going

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Speaker 2: to tell us that today, but let's start even earlier. So, like,

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Speaker 2: what are rings? I guess I realized, Well, I was

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Speaker 2: thinking about this question, like, you know, the moon orbits

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Speaker 2: in a ring, but that's not a ring. How continuous

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Speaker 2: does the line need to be before you have a

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Speaker 2: satellite versus a ring?

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Speaker 1: Yeah, so it's astronomy, which means we're going to do

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Speaker 1: our best to draw arbitrary dotted lines between the continuous

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Speaker 1: concepts that really exist on a spectrum. But you know,

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Speaker 1: some things we call moons, some things we call rings.

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Speaker 1: What's the difference? How many tiny moons does it take

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Speaker 1: before you start calling it a ring? Typically we call

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Speaker 1: something a ring if it's composed of solid materials such

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Speaker 1: as dust or moonlits, But it's not in one single object.

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Speaker 1: So you know, basically there's a spectrum between Like you

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Speaker 1: have one single object, you call that a moon. If

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Speaker 1: you break that moon up into little rocks, you could

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Speaker 1: call those moonlits, Or you could say if they're fine

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Speaker 1: enough you could call it a ring.

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Speaker 2: But if you had two objects as big as the

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Speaker 2: Moon that somehow didn't run into each other, would that

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Speaker 2: be a ring. Does Mars have a ring or does

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Speaker 2: it just have two moons?

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Speaker 1: Mars has two moons, so I think there isn't a

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Speaker 1: very crisp distinction. I couldn't find a crisp distinction online.

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Speaker 1: I don't think like the astronomers have had a meeting

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Speaker 1: arguing about this yet.

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Speaker 2: Nature doesn't care about our criteria in our categories.

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Speaker 1: But I think one thing that is important for a

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Speaker 1: ring is that it's basically in a plane. So, you know,

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Speaker 1: a swarm of objects surrounding a planet, you wouldn't call

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Speaker 1: that a ring. If it's like in a sphere. If

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Speaker 1: it's orbiting in every direction and completely surrounding the planet

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Speaker 1: with little rocks, that isn't a ring. When distinguishing feature

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Speaker 1: of a ring is that it does orbit in a plane, right, that, like,

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Speaker 1: the vertical motion relative to the ring is small compared

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Speaker 1: to the motion around the planet.

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Speaker 2: Does it happen that you get junk like all around

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Speaker 2: a planet or does it always end up in the

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Speaker 2: same plane as a ring?

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Speaker 1: Yeah? Great question. You can get junk around a planet,

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Speaker 1: but that's sort of temporary. That's not a very stable

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Speaker 1: situation because gravity will eventually pull it down together into

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Speaker 1: a plane. There's a reason that planets have rings and

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Speaker 1: not swarms of stuff. And there's a reason that moons

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Speaker 1: typically form in a single plane around a planet, which

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Speaker 1: aligns with the planet's spin usually, And it's the same

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Speaker 1: reason why the planets all spin in the same plane

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Speaker 1: as their motion around the Sun, which aligns with the

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Speaker 1: rotation of the Sun. And the reason is angular momentum.

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Speaker 1: Gravity would like to pull everything down together into a

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Speaker 1: little dot. What resists that, Well, sometimes it's like structural

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Speaker 1: or integrity. The Earth doesn't collapse into a black hole

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Speaker 1: because it's solid, right, and the rocks resist being crushed.

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Speaker 1: But there's another factor there, which is the Earth is spinning,

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Speaker 1: and the spinning of the Earth sort of fluffs it

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Speaker 1: up a little bit and makes it larger. So like

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Speaker 1: the Earth's radius from the core to the surface is

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Speaker 1: larger at the equator because it's spinning, and if the

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Speaker 1: Earth was softer like pizza dough, it would get flatter

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Speaker 1: and flatter as that spinning resists gravity. But the spinning

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Speaker 1: only resists gravity along the plane. Right, So if you

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Speaker 1: have like the Earth spin axis, the spinning helps resist gravity,

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Speaker 1: helps keep Earth fluffed out along the plane of that

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Speaker 1: spin right, so the axis is perpendicular to the plane,

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Speaker 1: but it doesn't prevent things from collapsing to the plane.

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Speaker 1: So now I imagine you have a big swarm of

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Speaker 1: stuff that's swirling around the Earth. Gravity can pull it

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Speaker 1: down into that plane, making a disk, but the spinning

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Speaker 1: keeps gravity from pulling it down into the Earth necessarily.

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Speaker 1: That's why a big swarm of stuff would collapse into

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Speaker 1: a plane. And it's the same reason why the whole

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Speaker 1: solar system has collapsed into a plane. The original blob

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Speaker 1: of gas and dust that formed our solar system collapse

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Speaker 1: due to gravity, but didn't collapse as far along that plane.

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Speaker 1: Because everything is spinning, it keeps stuff from falling all

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Speaker 1: the way in.

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Speaker 2: So if you had a speck around the Earth, not

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Speaker 2: around like the plane where you get the ring, would

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Speaker 2: it get thrown out or pulled in or either?

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Speaker 1: Yeah? So say, for example, Earth has a big ring

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Speaker 1: and now you add a rock in a random orientation

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Speaker 1: to the Earth. What's going to happen to it? Well,

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Speaker 1: it has a lot of al so it's not going

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Speaker 1: to fall to the Earth. It's going to be an orbit,

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Speaker 1: but it's going to get gravitated towards the ring. The

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Speaker 1: ring is going to pull it in, and so while

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Speaker 1: it's going to maintain an orbit because of its speed,

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Speaker 1: that orbit's going to shift until it joins the ring.

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Speaker 1: The ring, because of its gravity, is going to pull

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Speaker 1: that new rock into it. So gravity pulls things together,

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Speaker 1: but it can't overcome angular momentum.

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Speaker 2: Okay, And are rings always at the equator of the

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Speaker 2: thing that they're orbiting around, And if the thing is

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Speaker 2: at a tilt, that's why it doesn't look like it's

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Speaker 2: straight around. So like Saturn, is that a tilt and

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Speaker 2: that's why it's rings are kind of tilty.

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Speaker 1: Yes, great question, And it depends a little bit on

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Speaker 1: the formation. And this is actually a question people have

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Speaker 1: about how rings form, Like if the ring formed from

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Speaker 1: the original blob of stuff that made the planet. And

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Speaker 1: one of the theories for how rings formed is you

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Speaker 1: have a big blob of stuff and some of it

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Speaker 1: collapses into a planet, and some of it doesn't because

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Speaker 1: it's moving too fast and it stays outside and forms

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Speaker 1: a ring. Then it all comes from the initial blob

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Speaker 1: of stuff that's spin, and then you expect it to

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Speaker 1: have the same spin on the same plane and basically

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Speaker 1: be around the equator of the planet. But another theory

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Speaker 1: is that these rings come from the outside. You have

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Speaker 1: a planet that forms, it's already spinning and hard and compact,

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Speaker 1: and now some material comes from the outside is captured

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Speaker 1: by the planet into a ring that will collapse on

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Speaker 1: its own, but its axis doesn't have to align with

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Speaker 1: the axis of the planet. Gravity will pull it down

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Speaker 1: into a single ring and it will orbit around its

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Speaker 1: own spin axis. It doesn't have to align with the planet.

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Speaker 1: There's nothing the planet can do to change its spin

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Speaker 1: axis because angular momentum is conserved.

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Speaker 2: All right, Is there anything else we need to know

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Speaker 2: about how rings are formed? Are we all now experts?

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Speaker 1: Another thing to think about is the difference between the

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Speaker 1: formation of moons and rings, Like, why do some planets

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Speaker 1: have rings and some of them have moons and some

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Speaker 1: of them have both? You know, why doesn't gravity always

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Speaker 1: pull a ring together into a moon? Right? You could

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Speaker 1: imagine like a string of little moonlits orbiting together in

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Speaker 1: a circle r planet. Why doesn't gravity always pull those together.

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Speaker 1: It can do that without violating anyngular momentum. And the

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Speaker 1: answer there is tidal forces. Usually when we think about

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Speaker 1: the Solar System, we're thinking about gravity as just like

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Speaker 1: here you have a rock and there you have a rock,

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Speaker 1: and there's gravity between them and they're pulling on each other.

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Speaker 1: But gravity is a little bit more complex than that.

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Speaker 1: If your rocks are not just points objects. If they're

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Speaker 1: just points, then you can just think about the gravity

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Speaker 1: on the objects. But if it's big, then you have

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Speaker 1: one side that's closer and another side that's further, and

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Speaker 1: gravity depends on distance. So gravity is going to pull

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Speaker 1: on the closer part harder than it's pulling on the

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Speaker 1: further part. And that's true always. So for example, if

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Speaker 1: you're an astronaut and you're in space and you're doing

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Speaker 1: an ev or whatever, the Earth is pulling on your

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Speaker 1: feet harder than it's pulling on your head. You might think,

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Speaker 1: no big deal, But those are relative forces. You can

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Speaker 1: think of it as pulling on your feet harder than

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Speaker 1: your head, or equivalently, you can think the Earth is

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Speaker 1: trying to pull your head off of your body, because

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Speaker 1: that's really what it's doing, right, It's pulling on one

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Speaker 1: side harder than the other side. It's trying to tear

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Speaker 1: you apart. And normally your neck is strong enough that

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Speaker 1: the Earth's not going to decapitate you. But if you

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Speaker 1: are close to a very powerful body like a black hole,

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Speaker 1: then those tidle forces are powerful enough to pull you apart.

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Speaker 1: That's what spaghetification is. And so planets pull on things.

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Speaker 1: The Earth, for example, is tugging on the Moon. It's

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Speaker 1: trying to squeeze the Moon into a football. It's trying

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Speaker 1: to pull rocks off the surface of the Moon that's

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Speaker 1: closer to it.

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Speaker 2: I can imagine how that pulling over time would start

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Speaker 2: to pull off pieces and result in a ring. So

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Speaker 2: does that mean that a lot of the rings around

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Speaker 2: planets are moons that just got kind of crushed? And

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Speaker 2: then why didn't our moon end up succumbing to that?

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Speaker 1: Sure, it depends on distance. It also depends on structural

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Speaker 1: integrity what your moon is made out of. But basically,

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Speaker 1: if a moon gets too close to a planet, the

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Speaker 1: tidle forces will pull it apart. If the moon is

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Speaker 1: far enough away, then the structural integrity of the moon

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Speaker 1: is more powerful than the tidal forces. It'll stay together.

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Speaker 1: So if you look at all the planets in the

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Speaker 1: Solar System, you notice that it's usually rings on the

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Speaker 1: inside and moons on the outside. And you can calculate

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Speaker 1: this sort of dividing line. It's called the Roche limit.

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Speaker 1: Things that are closer than the roach limit, the tidal

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Speaker 1: forces will probably pull it apart. Things that are further

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Speaker 1: things will coalesce into a moon. The self gravity will

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Speaker 1: pull it together, and then the structural forces will hold it.

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Speaker 2: Is it an interplay between distance and size or is

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Speaker 2: it just size or distance? Size and what you're made

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Speaker 2: out of, like a chunk of metal, would be harder

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Speaker 2: to pull apart than something else.

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Speaker 1: It's mostly distance from the planet and what you're made

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Speaker 1: out of. So, for example, there's a different roach limit

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Speaker 1: for a blob of water than there is for like

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Speaker 1: a moon made of diamond, which would be much harder

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Speaker 1: to pull apart, but for like a typical rock. You

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Speaker 1: can calculate these distances. For the moon, for example, if

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Speaker 1: it came within ten thousand kilometers of the surface of

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Speaker 1: the Earth, it would be pulled apart. Its orbit is

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Speaker 1: safely outside that. It's like three hundred and ninety thousand kilometers,

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Speaker 1: so it's well past the Roach limit. And you know,

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Speaker 1: the Sun has a roach limit. If a planet gets

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Speaker 1: too close to the Sun, it would get pulled apart

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Speaker 1: by its tidal forces. So, for example, the Earth came

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Speaker 1: within almost a million kilometers of the Sun, it would

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Speaker 1: get pulled apart. We're like one hundred and fifty million kilometers,

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Speaker 1: so we're in no danger. But this is the distinguishing

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Speaker 1: feature between rings and moons, basically how far you are

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Speaker 1: from the surface of the planet.

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Speaker 2: You know. Now, anytime we discuss something that's named after someone,

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Speaker 2: and I'm guessing the roof limit is named after it Roach. Yeah,

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Speaker 2: I find myself wanting to have Kathy Johnson back because

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Speaker 2: I want to be like, Kathy, did Roche really come

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Speaker 2: up with this? Or who was he building on? What

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Speaker 2: were people thinking at the time? She should just always

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Speaker 2: give us the background on everything, because she's wonderful.

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Speaker 1: M m yeah. And science is a human story, which

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Speaker 1: means that every time you learn a little bit of knowledge,

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Speaker 1: there's a fascinating, probably tortured history for how we figure

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Speaker 1: that out and how it is named after this person

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Speaker 1: and whether that person was actually a jerk, and if

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Speaker 1: their paper was full of mistakes, and whether they deserve

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Speaker 1: the credit for that or not. Human history is always fascinating.

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Speaker 1: Every time you lift up the rug you find really

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Speaker 1: interesting stuff under there.

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Speaker 2: I want you check out if you missed it, our

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Speaker 2: episode on Maxwell's equation, to hear Kathy's amazing history, and

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Speaker 2: also to make you feel better if you're not good at.

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Speaker 1: Math, because neither was fair Day or Maxwell. Apparently Maxwell

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Speaker 1: was good at math. He just wasn't good at keeping

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Speaker 1: track of minus signs. But hey, who is He got.

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Speaker 2: Away with a lot of mistakes. Yes, all right, that's true.

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Speaker 1: I have fewer published math errors than Max.

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Speaker 2: There you go. You should feel good about that. You

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Speaker 2: should get a plaque to put over your desk.

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Speaker 1: Maybe just a T shirt.

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Speaker 2: There you go, that's right here, mistakes than Maxwell. It's

436
00:20:33,040 --> 00:20:36,359
Speaker 2: got to be a pretty niche audience for that T shirt. Okay,

437
00:20:37,480 --> 00:20:40,560
Speaker 2: all right, Well, we're all missing Kathy right now, but

438
00:20:40,560 --> 00:20:42,120
Speaker 2: there's nothing we can do about it at the moment.

439
00:20:42,160 --> 00:20:43,960
Speaker 2: So let's take a break to think about how great

440
00:20:44,000 --> 00:20:46,080
Speaker 2: Kathy is, and when we come back, we'll talk about

441
00:20:46,119 --> 00:21:05,040
Speaker 2: what those rings tend to be made of. All right, So,

442
00:21:05,119 --> 00:21:07,680
Speaker 2: based on our earlier conversation, I'm guessing that a lot

443
00:21:07,720 --> 00:21:10,359
Speaker 2: of rings are made out of you know, like moves

444
00:21:10,359 --> 00:21:13,280
Speaker 2: that got crushed, so probably you know, rocks and metal

445
00:21:13,320 --> 00:21:15,600
Speaker 2: and stuff. What else do we get out there.

446
00:21:15,880 --> 00:21:17,919
Speaker 1: Yeah, so the rings tend to be made out of

447
00:21:17,920 --> 00:21:20,040
Speaker 1: the same stuff that the solar system is made out of.

448
00:21:20,240 --> 00:21:22,919
Speaker 1: So the inner Solar system it's mostly rocky because you

449
00:21:22,920 --> 00:21:25,439
Speaker 1: know the solar system, well, it starts out mostly gas,

450
00:21:25,920 --> 00:21:28,280
Speaker 1: but all that gas gets gobbled up by the Sun

451
00:21:28,680 --> 00:21:31,280
Speaker 1: and any gas left over and the inner Solar system

452
00:21:31,359 --> 00:21:34,239
Speaker 1: got blasted out of it by the Sun's radiation, so

453
00:21:34,280 --> 00:21:35,600
Speaker 1: you don't have a whole lot of gas left in

454
00:21:35,600 --> 00:21:38,120
Speaker 1: the inner Solar system. The rings closer to the Sun

455
00:21:38,200 --> 00:21:40,959
Speaker 1: are going to be rockier. Further out, you're more distant

456
00:21:40,960 --> 00:21:43,280
Speaker 1: from the Sun, so you can have things like water crystals,

457
00:21:43,920 --> 00:21:47,320
Speaker 1: and outpast what we call the frost line, where water

458
00:21:47,400 --> 00:21:50,760
Speaker 1: isn't vaporized by the Sun, you have ice. And so,

459
00:21:50,880 --> 00:21:54,600
Speaker 1: for example, beyond Jupiter, there's a lot of ice in

460
00:21:54,640 --> 00:21:55,360
Speaker 1: those rings.

461
00:21:55,600 --> 00:21:58,520
Speaker 2: So you don't get any ice in rings between the

462
00:21:58,560 --> 00:22:02,040
Speaker 2: Sun and Jupiter, but outwards you can get ice and rings.

463
00:22:02,440 --> 00:22:05,399
Speaker 1: Yeah, exactly right, And so we have some pretty spectacular

464
00:22:05,520 --> 00:22:07,919
Speaker 1: ring systems in the solar system right, and one of

465
00:22:07,920 --> 00:22:10,760
Speaker 1: the first ever to be seen was Saturn's This is

466
00:22:10,760 --> 00:22:13,160
Speaker 1: one of the first things actually that Galileo saw through

467
00:22:13,200 --> 00:22:16,359
Speaker 1: his telescope on those cold Italian nights in the early

468
00:22:16,440 --> 00:22:20,119
Speaker 1: sixteen hundreds are the rings of Saturn, which of you know,

469
00:22:20,160 --> 00:22:23,040
Speaker 1: anybody who's used a telescope in their backyard knows that

470
00:22:23,119 --> 00:22:24,639
Speaker 1: this is an amazing thing to see.

471
00:22:24,720 --> 00:22:26,879
Speaker 2: I can't imagine being the first one to see that

472
00:22:26,960 --> 00:22:29,600
Speaker 2: must have been just absolutely mind blowing right.

473
00:22:29,600 --> 00:22:32,040
Speaker 1: Right to me. It's always exciting when you can resolve

474
00:22:32,119 --> 00:22:34,920
Speaker 1: any feature on these objects in the night sky. Like

475
00:22:34,960 --> 00:22:36,680
Speaker 1: you look at the Moon and you can see things

476
00:22:36,760 --> 00:22:39,119
Speaker 1: on the surface. That's super cool because it's not just

477
00:22:39,160 --> 00:22:41,600
Speaker 1: like a point, and seeing the rings of Saturn is

478
00:22:41,640 --> 00:22:43,840
Speaker 1: the same way. You're like, I'm seeing something that's really

479
00:22:43,920 --> 00:22:45,920
Speaker 1: out there. I don't know about you, but when I

480
00:22:45,920 --> 00:22:48,159
Speaker 1: look at the night sky, it's just too easy to

481
00:22:48,240 --> 00:22:50,919
Speaker 1: think of it as like a screen with dots on it.

482
00:22:51,280 --> 00:22:54,840
Speaker 1: But when you can resolve features on something, then suddenly

483
00:22:54,880 --> 00:22:57,760
Speaker 1: I'm transported to this mode where I understand I'm looking

484
00:22:58,160 --> 00:23:03,480
Speaker 1: across an incredibly vast ocean of nothingness to huge objects

485
00:23:03,520 --> 00:23:06,359
Speaker 1: that are incredibly distant you know, it's so difficult for

486
00:23:06,400 --> 00:23:09,560
Speaker 1: your mind to really put yourself in that vast three

487
00:23:09,640 --> 00:23:11,800
Speaker 1: D space. But on a clear night when you can

488
00:23:11,800 --> 00:23:13,800
Speaker 1: see the rings of Saturn or the moons of Jupiter,

489
00:23:14,000 --> 00:23:17,400
Speaker 1: I feel like it's easier to visualize yourself in this

490
00:23:17,520 --> 00:23:20,040
Speaker 1: vast space rather than thinking of it as a screen.

491
00:23:20,240 --> 00:23:22,159
Speaker 2: Well, part of me feels like this is cheating, but

492
00:23:22,240 --> 00:23:24,639
Speaker 2: I love those apps on my iPhone where you look

493
00:23:24,680 --> 00:23:26,159
Speaker 2: up at the night sky and it tells you like,

494
00:23:26,240 --> 00:23:29,720
Speaker 2: that's Saturn, that's Venus, and like, to me, I get

495
00:23:29,760 --> 00:23:32,600
Speaker 2: all philosophical when I get that extra detail. It makes

496
00:23:32,640 --> 00:23:34,960
Speaker 2: me feel like I'm more of a small speck than

497
00:23:35,000 --> 00:23:36,240
Speaker 2: if I just look out at it. Like you said,

498
00:23:36,240 --> 00:23:38,320
Speaker 2: it's almost like you've got a sheet with little pin

499
00:23:38,359 --> 00:23:40,800
Speaker 2: pricks in it and lights coming through. It's like easy

500
00:23:40,800 --> 00:23:43,680
Speaker 2: to not think about it as a vast expanse out there.

501
00:23:43,720 --> 00:23:46,000
Speaker 2: But anyway, yea for technology, there's an app for that.

502
00:23:49,520 --> 00:23:51,840
Speaker 1: Well. The rings of Saturn are really incredible because they're

503
00:23:51,880 --> 00:23:54,320
Speaker 1: so very There are a bunch of different rings are separated,

504
00:23:55,160 --> 00:23:58,199
Speaker 1: and NASA has given them really creative names. There's the

505
00:23:58,240 --> 00:24:01,080
Speaker 1: A ring, the B ring, the C you know, goes

506
00:24:01,119 --> 00:24:03,840
Speaker 1: out to the G ring and the E ring, which

507
00:24:03,880 --> 00:24:06,120
Speaker 1: are sort of harder to see with your naked eye.

508
00:24:06,160 --> 00:24:07,960
Speaker 1: Some of these things have like a lot of dark

509
00:24:08,119 --> 00:24:11,119
Speaker 1: organic compounds, so they're not as easy to see. The

510
00:24:11,119 --> 00:24:14,199
Speaker 1: inner ones have more ice, like they're just basically a

511
00:24:14,200 --> 00:24:17,880
Speaker 1: bunch of icy particles spread out in these vast, very

512
00:24:17,920 --> 00:24:18,760
Speaker 1: flat rings.

513
00:24:19,119 --> 00:24:21,399
Speaker 2: Who should be naming these right? You know? So NASA

514
00:24:21,760 --> 00:24:24,399
Speaker 2: clearly shouldn't be allowed to name things because they're not

515
00:24:24,440 --> 00:24:25,879
Speaker 2: doing a good job. But you like, if you let

516
00:24:25,920 --> 00:24:27,760
Speaker 2: the Internet name them, it would have been like ringy

517
00:24:27,840 --> 00:24:31,320
Speaker 2: mcring face. What is the right solution here for these

518
00:24:31,359 --> 00:24:34,360
Speaker 2: amazing celestial objects. I think they should be renamed, That's

519
00:24:34,400 --> 00:24:34,920
Speaker 2: what I think.

520
00:24:35,200 --> 00:24:38,360
Speaker 1: Yeah, absolutely, I think they should not be named by scientists.

521
00:24:38,400 --> 00:24:41,160
Speaker 1: Maybe we should have Joge on the podcast to suggest names.

522
00:24:41,160 --> 00:24:41,879
Speaker 1: He was always good at.

523
00:24:41,880 --> 00:24:42,880
Speaker 2: That sounds good.

524
00:24:43,040 --> 00:24:45,679
Speaker 1: But there are these fascinating gaps between the rings, like

525
00:24:45,720 --> 00:24:48,160
Speaker 1: there's the A ring and the B ring, And we've

526
00:24:48,160 --> 00:24:51,399
Speaker 1: known about these gaps forever. It was Cassini, in like

527
00:24:51,480 --> 00:24:54,760
Speaker 1: the latest sixteen hundreds who first saw these gaps. And

528
00:24:54,800 --> 00:24:57,320
Speaker 1: that's why we call that spacecraft that visited Sounder and

529
00:24:57,359 --> 00:25:00,119
Speaker 1: the Cassini spacecraft, because he was the first one and

530
00:25:00,200 --> 00:25:02,960
Speaker 1: see them. And these gaps in the rings come from

531
00:25:02,960 --> 00:25:06,440
Speaker 1: actually the interactions of the ring material with little moons,

532
00:25:07,040 --> 00:25:08,439
Speaker 1: you know. So we talked about how like they are

533
00:25:08,480 --> 00:25:11,680
Speaker 1: only moons out past the rings, but if you're small enough,

534
00:25:11,720 --> 00:25:14,560
Speaker 1: you're gonna avoid those tidal forces. You're like basically a

535
00:25:14,600 --> 00:25:17,920
Speaker 1: big chunk of rock within the ring. Is it really

536
00:25:18,000 --> 00:25:20,080
Speaker 1: part of the ring? Is it a moonlit Now we're

537
00:25:20,119 --> 00:25:22,680
Speaker 1: getting into that murky territory where the dotted lines don't

538
00:25:22,680 --> 00:25:25,920
Speaker 1: make any sense. But these rings sometimes are called shepherd

539
00:25:26,000 --> 00:25:29,720
Speaker 1: rings shepherd moons because they orbit near the edges of

540
00:25:29,800 --> 00:25:32,919
Speaker 1: these rings and they can help keep the material in place.

541
00:25:32,920 --> 00:25:37,840
Speaker 1: There's these fascinating gravitational interactions between the ring and the moon.

542
00:25:38,320 --> 00:25:41,120
Speaker 2: Huh And okay, so the moon is countering Saturn's gravity

543
00:25:41,160 --> 00:25:42,760
Speaker 2: to keep some of the stuff in the ring in

544
00:25:42,800 --> 00:25:45,680
Speaker 2: its place. How is the moon clearing its own orbit?

545
00:25:45,760 --> 00:25:48,240
Speaker 2: Is it's gravity pulling anything else that might have been

546
00:25:48,640 --> 00:25:51,080
Speaker 2: in a ring in that location, It's pulling it into itself.

547
00:25:51,359 --> 00:25:54,000
Speaker 1: Yeah, essentially, it's acting like a little shepherd. It helps

548
00:25:54,080 --> 00:25:57,200
Speaker 1: keep the edge of the ring sharply defined because anything

549
00:25:57,200 --> 00:26:00,840
Speaker 1: that gets too close gets secreted onto the moon, or

550
00:26:00,920 --> 00:26:03,439
Speaker 1: it can make a near miss and can get accelerated

551
00:26:03,480 --> 00:26:05,680
Speaker 1: by the Moon and then deflect it back away from

552
00:26:05,720 --> 00:26:09,520
Speaker 1: the Moon like a slingshot back into the ring. That's

553
00:26:09,520 --> 00:26:11,360
Speaker 1: how it keeps its own like a little lane. That's

554
00:26:11,359 --> 00:26:13,800
Speaker 1: why you get these gaps in the rings. It's really

555
00:26:13,880 --> 00:26:17,560
Speaker 1: fascinating that these rings are really really broad, right, they're

556
00:26:17,640 --> 00:26:22,399
Speaker 1: like seventy thousand kilometers wide, the rings of Saturn, and

557
00:26:22,440 --> 00:26:27,200
Speaker 1: they're only twenty meters thick. That's meters, not kilometers.

558
00:26:27,280 --> 00:26:27,760
Speaker 2: Oh wow.

559
00:26:28,040 --> 00:26:29,560
Speaker 1: Yeah, it's the scale of like if you had a

560
00:26:29,600 --> 00:26:31,440
Speaker 1: sheet of paper, the sheet of paper would be like

561
00:26:31,480 --> 00:26:36,479
Speaker 1: a kilometer wide. Right. It's incredibly thin compared to the

562
00:26:36,520 --> 00:26:39,399
Speaker 1: breadth of it, and that's due to anglar momentum and gravity.

563
00:26:39,440 --> 00:26:41,720
Speaker 1: Gravity has done its work to collapse it down to

564
00:26:41,760 --> 00:26:44,240
Speaker 1: a thin sheet, but it can't do it in the

565
00:26:44,280 --> 00:26:47,160
Speaker 1: sort of plane of rotation because of angular momentum.

566
00:26:47,280 --> 00:26:49,280
Speaker 2: Kind of amazing that we can see anything that thin

567
00:26:49,560 --> 00:26:50,400
Speaker 2: from all the way here.

568
00:26:50,800 --> 00:26:53,520
Speaker 1: It's because it's reflective. It's the icy particles that make

569
00:26:53,560 --> 00:26:54,439
Speaker 1: it possible to see it.

570
00:26:54,520 --> 00:26:56,560
Speaker 2: Oh okay, all right, so then where did Saturn get

571
00:26:56,560 --> 00:26:59,919
Speaker 2: this ring in the first place. Was Jupiter feeling amorous

572
00:27:00,080 --> 00:27:00,919
Speaker 2: at some point.

573
00:27:02,880 --> 00:27:05,520
Speaker 1: You know, the story of Saturn's rings is interesting history.

574
00:27:05,560 --> 00:27:07,639
Speaker 1: It used to be that people thought this is probably

575
00:27:07,720 --> 00:27:10,960
Speaker 1: left over from formation of Saturn because it does orbit

576
00:27:11,040 --> 00:27:14,280
Speaker 1: in the plane of Saturn, and it seemed like, wow,

577
00:27:14,320 --> 00:27:16,560
Speaker 1: this must have been here for a long time. But

578
00:27:16,680 --> 00:27:20,080
Speaker 1: Cassini's visits revealed that the rings are quite low mass.

579
00:27:20,520 --> 00:27:22,600
Speaker 1: You know, there's like less stuff in there than we thought,

580
00:27:22,640 --> 00:27:25,560
Speaker 1: and it's still very sharp and bright, Like the edges

581
00:27:25,600 --> 00:27:29,280
Speaker 1: of these ice crystals are still very sharp, which isn't

582
00:27:29,320 --> 00:27:32,040
Speaker 1: consistent with like being there a long time. You know,

583
00:27:32,119 --> 00:27:35,119
Speaker 1: things tit to get rounded and collisions tend to soften stuff.

584
00:27:35,720 --> 00:27:38,240
Speaker 1: And more recent theory is that some moons of Saturn

585
00:27:38,359 --> 00:27:41,000
Speaker 1: might have collided and left a huge spray of debris

586
00:27:41,480 --> 00:27:44,240
Speaker 1: which basically formed into a ring, which might mean that

587
00:27:44,280 --> 00:27:47,720
Speaker 1: these rings themselves are temporary. It might be the Saturn

588
00:27:47,800 --> 00:27:51,720
Speaker 1: gathers them back together into moons. We don't quite know,

589
00:27:52,320 --> 00:27:54,840
Speaker 1: because the roche limit is a little bit fuzzy, you know,

590
00:27:54,880 --> 00:27:58,000
Speaker 1: the structural integrity. If those rings will be there in

591
00:27:58,040 --> 00:27:58,960
Speaker 1: one hundred million.

592
00:27:58,800 --> 00:28:00,800
Speaker 2: Years, oh man, and we're not gonna be around to know.

593
00:28:01,840 --> 00:28:04,160
Speaker 1: How do you know? Come on, We're gonna have great, great,

594
00:28:04,200 --> 00:28:07,800
Speaker 1: great great great grandkids making non sentimental marriage proposals to

595
00:28:07,840 --> 00:28:10,280
Speaker 1: each other using ice from the rings of Saturn.

596
00:28:11,760 --> 00:28:14,080
Speaker 2: Your grand kids are going to are we getting into

597
00:28:14,119 --> 00:28:15,160
Speaker 2: incestuous to Oh?

598
00:28:15,800 --> 00:28:19,120
Speaker 1: I mean humanity's descendants. I couldn't say enough great great

599
00:28:19,119 --> 00:28:21,199
Speaker 1: grades to get us one hundred million years. But are

600
00:28:21,240 --> 00:28:23,240
Speaker 1: you not optimistic that people will be living in the

601
00:28:23,280 --> 00:28:25,080
Speaker 1: Solar System in one hundred million years? Hi?

602
00:28:25,240 --> 00:28:27,040
Speaker 2: No, I'm optimistic all right.

603
00:28:27,280 --> 00:28:29,520
Speaker 1: Somebody will be here to see the new moons of

604
00:28:29,560 --> 00:28:31,720
Speaker 1: Saturn and to give them a creative name.

605
00:28:31,880 --> 00:28:34,120
Speaker 2: I hope somebody gets on that much sooner. I don't

606
00:28:34,160 --> 00:28:35,879
Speaker 2: want to wait for that to happen.

607
00:28:38,240 --> 00:28:41,360
Speaker 1: And other planets in the Solar System have fascinating histories

608
00:28:41,400 --> 00:28:44,520
Speaker 1: with rings, Like Astronomers think that Mars has gone through

609
00:28:44,560 --> 00:28:48,520
Speaker 1: several cycles of having rings and moons and rings and moons.

610
00:28:48,680 --> 00:28:51,000
Speaker 2: Wait, so does that mean that like Phobos and Demos

611
00:28:51,000 --> 00:28:54,360
Speaker 2: have broken up and come back together multiple times or well,

612
00:28:54,400 --> 00:28:54,880
Speaker 2: we don't.

613
00:28:54,680 --> 00:28:57,240
Speaker 1: Know how long phobos and demos will last, but we

614
00:28:57,320 --> 00:29:01,240
Speaker 1: think that Phobos and Demos formed from a ring that

615
00:29:01,560 --> 00:29:04,520
Speaker 1: was created from a giant impact. So like something hit

616
00:29:04,600 --> 00:29:08,239
Speaker 1: Mars and then ejected a huge amount of stuff like

617
00:29:08,680 --> 00:29:12,280
Speaker 1: ten to the twenty three kilograms of stuff into orbit

618
00:29:12,840 --> 00:29:16,120
Speaker 1: and left this huge debris cloud around Mars, which then

619
00:29:16,200 --> 00:29:19,520
Speaker 1: collapsed into a ring which then got gathered together into

620
00:29:19,560 --> 00:29:20,640
Speaker 1: these small moons.

621
00:29:21,040 --> 00:29:24,240
Speaker 2: So is it possible to look at a moon and

622
00:29:24,360 --> 00:29:27,719
Speaker 2: figure out if it's gathered up ring or not? Like

623
00:29:27,760 --> 00:29:29,360
Speaker 2: that's got to be hard.

624
00:29:30,240 --> 00:29:33,160
Speaker 1: It's not always possible to tell the history, but you

625
00:29:33,200 --> 00:29:36,840
Speaker 1: can get some clues, like, for example, Phobos and Demos

626
00:29:36,840 --> 00:29:39,680
Speaker 1: have very circular orbits, which suggests that you had like

627
00:29:39,720 --> 00:29:41,600
Speaker 1: a lot of stuff which formed a ring and then

628
00:29:41,640 --> 00:29:45,440
Speaker 1: gathered together, rather than being single objects that were like

629
00:29:45,600 --> 00:29:48,680
Speaker 1: captured as they floated near Mars, which would tend to

630
00:29:48,720 --> 00:29:51,320
Speaker 1: be like more elliptical orbits and not necessarily in the

631
00:29:51,320 --> 00:29:55,040
Speaker 1: same plane as Mars, So that suggests that it formed

632
00:29:55,080 --> 00:29:57,560
Speaker 1: from a ring. Also, you can look at the composition

633
00:29:57,680 --> 00:30:00,760
Speaker 1: of the stuff, and Phobos and Demo are made of

634
00:30:00,800 --> 00:30:04,800
Speaker 1: the same stuff as Mars is, which suggests, like our moon,

635
00:30:05,320 --> 00:30:08,040
Speaker 1: that it formed due to a giant impact rather than

636
00:30:08,160 --> 00:30:10,760
Speaker 1: like was captured. Sometimes moons can be captured. Some of

637
00:30:10,760 --> 00:30:13,239
Speaker 1: the moons of Saturn and Jupiter, we think are just

638
00:30:13,240 --> 00:30:16,320
Speaker 1: like big rocks that floated too close and got gobbled

639
00:30:16,400 --> 00:30:20,400
Speaker 1: up into the gravitational system of those planets not yet torn.

640
00:30:20,160 --> 00:30:23,040
Speaker 2: Apart, but hit the cosmic lottery and didn't get pulled

641
00:30:23,080 --> 00:30:24,200
Speaker 2: into the center.

642
00:30:26,360 --> 00:30:29,480
Speaker 1: Exactly. And if these things form moons and then they're

643
00:30:29,560 --> 00:30:32,480
Speaker 1: too close to the planet, like they'll drag, if there's

644
00:30:32,480 --> 00:30:35,080
Speaker 1: an atmosphere there, they'll drag and then eventually just fall

645
00:30:35,160 --> 00:30:38,000
Speaker 1: into the planet and so that you can lose your moon.

646
00:30:38,560 --> 00:30:41,600
Speaker 1: So there's evidence on Mars of several of these cycles,

647
00:30:41,640 --> 00:30:45,280
Speaker 1: like impact forms. A cloud makes a ring, then makes

648
00:30:45,280 --> 00:30:47,800
Speaker 1: a little moon, and that moon gets dragged down into

649
00:30:47,840 --> 00:30:51,080
Speaker 1: the planet and lost and you start again. So Mars

650
00:30:51,160 --> 00:30:53,560
Speaker 1: is like a really kind of checkered history with its moons.

651
00:30:53,600 --> 00:30:55,800
Speaker 1: It's got like a bunch of x's that it's gobbled up.

652
00:30:56,080 --> 00:30:58,760
Speaker 2: Oh man, yet, one more reason and not go to Mars.

653
00:31:00,640 --> 00:31:03,160
Speaker 2: So it sounds like these transitions are very chaotic and

654
00:31:03,240 --> 00:31:05,520
Speaker 2: would be dangerous if humans were living on the surface

655
00:31:05,560 --> 00:31:06,040
Speaker 2: at the time.

656
00:31:06,120 --> 00:31:08,720
Speaker 1: Oh yeah, No, you don't want to be around during

657
00:31:08,720 --> 00:31:10,720
Speaker 1: one of these transitions. And you don't want to be

658
00:31:10,760 --> 00:31:13,080
Speaker 1: around when you have like a huge dust cloud around

659
00:31:13,080 --> 00:31:15,000
Speaker 1: your planet either, because it's going to block a lot

660
00:31:15,000 --> 00:31:18,160
Speaker 1: of light. So you know, the temperature probably plummets on

661
00:31:18,200 --> 00:31:21,280
Speaker 1: the planet when you have a situation like that. In general,

662
00:31:21,320 --> 00:31:23,600
Speaker 1: it's probably really fun to watch from far away, but

663
00:31:23,720 --> 00:31:25,280
Speaker 1: not fun to watch from the surface.

664
00:31:25,640 --> 00:31:27,440
Speaker 2: And the connection with the dust cloud is because when

665
00:31:27,440 --> 00:31:29,280
Speaker 2: something plummets, it kicks up a bunch of dust.

666
00:31:29,320 --> 00:31:31,600
Speaker 1: Is that right, Yeah, a lot of these are formed

667
00:31:31,640 --> 00:31:34,280
Speaker 1: from an impact. So either you have something that comes

668
00:31:34,360 --> 00:31:36,360
Speaker 1: nearby and is torn apart and then you get a

669
00:31:36,360 --> 00:31:38,840
Speaker 1: cloud a debris, or you get actual impact on the

670
00:31:38,840 --> 00:31:42,120
Speaker 1: planet which kicks up huge piles of stuff from the planet,

671
00:31:42,240 --> 00:31:45,320
Speaker 1: which then coalesces into a ring and then a moon.

672
00:31:45,960 --> 00:31:48,080
Speaker 1: And so we used to think that Saturn was the

673
00:31:48,080 --> 00:31:50,600
Speaker 1: only planet in the Solar System that had rings, but

674
00:31:50,720 --> 00:31:53,240
Speaker 1: now we've discovered that rings are much more common. So,

675
00:31:53,320 --> 00:31:56,720
Speaker 1: for example, Jupiter has rings, but we've only known that

676
00:31:56,760 --> 00:32:00,320
Speaker 1: since nineteen seventy nine when Voyager went to visit. These

677
00:32:00,320 --> 00:32:02,160
Speaker 1: things are so faint that you either need to send

678
00:32:02,160 --> 00:32:04,160
Speaker 1: a probe to see them or have a very powerful

679
00:32:04,160 --> 00:32:07,400
Speaker 1: space telescope like Hubble. Can see the rings of Jupiter now,

680
00:32:07,600 --> 00:32:09,560
Speaker 1: but otherwise we couldn't see them from Earth.

681
00:32:09,760 --> 00:32:12,000
Speaker 2: And what are they named? One?

682
00:32:12,240 --> 00:32:13,520
Speaker 1: Two?

683
00:32:15,320 --> 00:32:17,320
Speaker 2: I hope we've done better with Jupiter's rings.

684
00:32:20,000 --> 00:32:23,480
Speaker 1: Maybe alpha beta, gamma delta. Yeah, that's a good question.

685
00:32:24,000 --> 00:32:26,800
Speaker 1: But these rings around Jupiter are very faint because they

686
00:32:26,800 --> 00:32:30,080
Speaker 1: mostly consist of these little dust particles that come from

687
00:32:30,080 --> 00:32:34,080
Speaker 1: like tiny meteors hitting the planet's moons and then being vaporized.

688
00:32:34,800 --> 00:32:37,400
Speaker 1: But this dust also doesn't last very long in the

689
00:32:37,480 --> 00:32:41,280
Speaker 1: Jovian System because Jupiter is crazy. It has really powerful

690
00:32:41,280 --> 00:32:45,200
Speaker 1: magnetic fields, and these basically pull these rings apart and

691
00:32:45,240 --> 00:32:48,560
Speaker 1: shepherd them up to the poles, and so a piece

692
00:32:48,640 --> 00:32:51,080
Speaker 1: of dust can only last in these rings for like

693
00:32:51,120 --> 00:32:54,400
Speaker 1: a few hundred years or a few thousand years, which

694
00:32:54,440 --> 00:32:59,000
Speaker 1: means that like Jupiter's rings are constantly being degraded and replenished,

695
00:32:59,360 --> 00:33:02,480
Speaker 1: like micro ears are hitting the moons, which them to

696
00:33:02,520 --> 00:33:05,280
Speaker 1: get vaporized and then they enjoin the ring. But there's

697
00:33:05,280 --> 00:33:08,320
Speaker 1: also an outflow, so it's not like a constant structure.

698
00:33:08,320 --> 00:33:11,160
Speaker 1: It's more like a river of dust that's moving through

699
00:33:11,160 --> 00:33:13,160
Speaker 1: this sort of like dust cycle around Jupiter.

700
00:33:13,280 --> 00:33:15,160
Speaker 2: It's probably nice to get some new bling from time

701
00:33:15,240 --> 00:33:17,240
Speaker 2: to time, you know, out with the old in with

702
00:33:17,320 --> 00:33:20,240
Speaker 2: the new ring.

703
00:33:20,640 --> 00:33:22,719
Speaker 1: Yeah, maybe you and Zac stually get new rings sometime.

704
00:33:23,000 --> 00:33:25,240
Speaker 2: Yeah. No, he'd just lose them and I would get

705
00:33:25,240 --> 00:33:26,960
Speaker 2: bug guts in them, and it would just not It

706
00:33:27,000 --> 00:33:28,680
Speaker 2: wouldn't work for us. It's all right.

707
00:33:28,800 --> 00:33:30,719
Speaker 1: Yeah, you know. I'm the same way. I lose stuff.

708
00:33:30,760 --> 00:33:33,400
Speaker 1: I put stuff down, I can't remember it, so I've

709
00:33:33,440 --> 00:33:35,320
Speaker 1: always been terrified I was gonna lose my ring. So

710
00:33:35,360 --> 00:33:37,800
Speaker 1: I just never ever ever take it off, Like that's

711
00:33:37,840 --> 00:33:40,280
Speaker 1: my rule. Not in the shower, I never take it

712
00:33:40,320 --> 00:33:42,680
Speaker 1: off because I'm afraid I lose it. Same with my glasses,

713
00:33:42,720 --> 00:33:45,000
Speaker 1: Like I wear glasses all the time. I actually only

714
00:33:45,040 --> 00:33:47,400
Speaker 1: need them for reading. Really, if I ever took them off,

715
00:33:47,480 --> 00:33:49,520
Speaker 1: they would be gone within a day. So I just

716
00:33:49,520 --> 00:33:53,000
Speaker 1: wear them all the time because I can't manage the other.

717
00:33:53,400 --> 00:33:55,880
Speaker 2: I'm just totally blind without mine, So I never take

718
00:33:55,920 --> 00:33:58,040
Speaker 2: mine off. But lately my kids think it's funny to

719
00:33:58,080 --> 00:34:00,840
Speaker 2: try to pull them off, and I do not think

720
00:34:00,880 --> 00:34:03,560
Speaker 2: that's funny at all, So we're working on that.

721
00:34:06,440 --> 00:34:08,600
Speaker 1: They think it's hilarious when mom bumps into stuff in

722
00:34:08,640 --> 00:34:09,120
Speaker 1: the kitchen.

723
00:34:09,239 --> 00:34:11,520
Speaker 2: I mean, yeah, I guess so. But then I remind

724
00:34:11,520 --> 00:34:13,359
Speaker 2: them like, oh, I can't drive you to go get

725
00:34:13,360 --> 00:34:15,600
Speaker 2: ice cream, And then they're like, oh, we found your glasses.

726
00:34:15,800 --> 00:34:17,840
Speaker 2: Like all that was easy.

727
00:34:18,920 --> 00:34:20,920
Speaker 1: Isn't it wonderful? As your kids grow up to be

728
00:34:20,960 --> 00:34:21,480
Speaker 1: real people.

729
00:34:21,560 --> 00:34:25,319
Speaker 2: Yeah, I know they're growing up to be bullies. I'll

730
00:34:25,360 --> 00:34:28,640
Speaker 2: do better, all right. So we've talked about how Mars

731
00:34:28,680 --> 00:34:33,040
Speaker 2: maybe had rings, Jupiter Saturn definitely have rings. How about Urytus,

732
00:34:34,680 --> 00:34:35,680
Speaker 2: She says with glee.

733
00:34:35,840 --> 00:34:37,880
Speaker 1: You're just desperate to talk about rings around Urinus.

734
00:34:37,920 --> 00:34:39,480
Speaker 2: I mean, what would an episode be without it?

735
00:34:41,160 --> 00:34:45,680
Speaker 1: So there are actually Uranian rings. The individual particles in

736
00:34:45,719 --> 00:34:49,640
Speaker 1: these rings are jet black like lumps of coal. And

737
00:34:49,840 --> 00:34:52,320
Speaker 1: we haven't visited close enough or been able to study

738
00:34:52,360 --> 00:34:55,080
Speaker 1: these enough to know exactly what they're made out of,

739
00:34:55,440 --> 00:34:58,759
Speaker 1: but they seem like some kind of carbon or hydrocarbon compounds.

740
00:34:58,760 --> 00:35:01,719
Speaker 1: They're not very well understood because they're so far out,

741
00:35:01,800 --> 00:35:04,680
Speaker 1: and they're so hard to see because they're black. Like, remember,

742
00:35:04,719 --> 00:35:07,200
Speaker 1: we can only see stuff that reflects light unless we

743
00:35:07,239 --> 00:35:10,160
Speaker 1: go and visit, and so jet black stuff out there

744
00:35:10,200 --> 00:35:12,960
Speaker 1: in the deep dark Solar system, it's very hard to study.

745
00:35:13,239 --> 00:35:16,319
Speaker 2: I would have so much fun naming things on a

746
00:35:16,440 --> 00:35:20,240
Speaker 2: Uranus mission rings and all that. Okay, let's take a break.

747
00:35:20,560 --> 00:35:23,239
Speaker 2: You think of what you would name Uranus rings if

748
00:35:23,239 --> 00:35:25,520
Speaker 2: you discovered them, And when we get back, let's talk

749
00:35:25,520 --> 00:35:44,480
Speaker 2: about whether or not Earth ever had a ring. All right,

750
00:35:44,560 --> 00:35:47,960
Speaker 2: So I am going to hope that Earth never has

751
00:35:48,040 --> 00:35:50,719
Speaker 2: another ring because I think that would probably result in

752
00:35:50,760 --> 00:35:53,840
Speaker 2: something catastrophic for the humans living on the planet. And actually,

753
00:35:53,840 --> 00:35:56,120
Speaker 2: have you ever read Seven Eves by I think it's

754
00:35:56,160 --> 00:35:56,920
Speaker 2: Neil Stevenson.

755
00:35:57,320 --> 00:36:00,360
Speaker 1: I have read Seven Eves and greatly enjoy it. It's

756
00:36:00,360 --> 00:36:03,160
Speaker 1: a fun book. I really wanted to know more about

757
00:36:03,320 --> 00:36:05,680
Speaker 1: what blows up the ring in that book. It's not

758
00:36:05,719 --> 00:36:08,239
Speaker 1: a spoiler because it happens in like chapter one, and

759
00:36:08,280 --> 00:36:10,120
Speaker 1: I thought, oh, this book is going to be about

760
00:36:10,200 --> 00:36:12,719
Speaker 1: understanding the mystery of what destroyed the moon, But he

761
00:36:12,800 --> 00:36:14,920
Speaker 1: just basically moves on to like what it's like to

762
00:36:14,960 --> 00:36:17,960
Speaker 1: live in that system, never answers the question like was

763
00:36:18,000 --> 00:36:20,920
Speaker 1: it an alien attack? Was it a random impactor? I

764
00:36:21,000 --> 00:36:24,080
Speaker 1: found that very unsatisfying. I mean, it's a great book. Otherwise,

765
00:36:24,200 --> 00:36:24,680
Speaker 1: I kind.

766
00:36:24,520 --> 00:36:27,040
Speaker 2: Of appreciated that. I felt like, you know, there's just

767
00:36:27,080 --> 00:36:28,600
Speaker 2: a lot of things we don't know the answer to,

768
00:36:28,719 --> 00:36:31,640
Speaker 2: and probably, like in a situation like that where you

769
00:36:31,719 --> 00:36:35,000
Speaker 2: think humanity is in peril, that probably goes to the

770
00:36:35,000 --> 00:36:37,440
Speaker 2: bottom of your to do list, like figuring out the

771
00:36:37,440 --> 00:36:40,120
Speaker 2: answer to that. But I had some questions about the

772
00:36:40,120 --> 00:36:41,840
Speaker 2: evolutionary biology stuff.

773
00:36:41,560 --> 00:36:44,200
Speaker 1: There, No we're science people. We're curious. You can't like

774
00:36:44,280 --> 00:36:46,480
Speaker 1: give us a huge mystery and then leave it unsolved.

775
00:36:46,560 --> 00:36:49,680
Speaker 1: That's the point of these books is to inflame your curiosity,

776
00:36:49,680 --> 00:36:52,200
Speaker 1: itch and then scratch it. You can't just inflame it.

777
00:36:52,360 --> 00:36:53,360
Speaker 1: That's really unfair.

778
00:36:53,440 --> 00:36:55,200
Speaker 2: I mean, there was a lot of other hard science

779
00:36:55,200 --> 00:36:55,680
Speaker 2: in that book.

780
00:36:55,800 --> 00:36:56,680
Speaker 1: No, there definitely was.

781
00:36:56,760 --> 00:36:59,400
Speaker 2: Yeah, if anyone knows mister Stevens said, we would love

782
00:36:59,400 --> 00:37:00,920
Speaker 2: to talk to him all the show let us see.

783
00:37:01,000 --> 00:37:04,239
Speaker 1: Yes, absolutely, please mister Stevenson, come talk to us. We

784
00:37:04,280 --> 00:37:05,040
Speaker 1: will be very nice.

785
00:37:05,160 --> 00:37:08,239
Speaker 2: We'll be huge nerds. All right, So let's hope that

786
00:37:08,280 --> 00:37:10,759
Speaker 2: Earth never has a ring into the future, but let's

787
00:37:10,800 --> 00:37:13,160
Speaker 2: look into our past when might we have had a ring?

788
00:37:13,400 --> 00:37:16,680
Speaker 1: So a lot of the answers from listeners were really insightful.

789
00:37:16,800 --> 00:37:19,840
Speaker 1: They were thinking about the early formation of the moon

790
00:37:20,320 --> 00:37:22,879
Speaker 1: and how that probably got gathered together from a big

791
00:37:22,960 --> 00:37:26,160
Speaker 1: cloud of stuff which probably initially formed into a ring.

792
00:37:26,640 --> 00:37:28,879
Speaker 1: And that's a very insightful answer. I think my only

793
00:37:28,960 --> 00:37:31,640
Speaker 1: quibble with that would be, like, was the Earth really

794
00:37:31,680 --> 00:37:34,680
Speaker 1: formed at that time? You know, we had the proto Earth,

795
00:37:34,719 --> 00:37:37,960
Speaker 1: which then got collided with Fea and formed a huge

796
00:37:38,000 --> 00:37:42,160
Speaker 1: swirling system which coalesced into the Earth and the Moon simultaneously.

797
00:37:42,280 --> 00:37:44,239
Speaker 1: So like, I don't know if that counts as the

798
00:37:44,280 --> 00:37:47,760
Speaker 1: Earth having a ring because the Earth itself was still forming.

799
00:37:48,280 --> 00:37:50,200
Speaker 1: But it's true that the Moon was likely a ring

800
00:37:50,239 --> 00:37:52,319
Speaker 1: of material before it formed a moon.

801
00:37:52,840 --> 00:37:54,120
Speaker 2: Oh interesting, But.

802
00:37:54,120 --> 00:37:56,520
Speaker 1: That was over four billion years ago, very very early

803
00:37:56,560 --> 00:37:59,759
Speaker 1: in the Solar system. There was actually another period much more,

804
00:38:00,400 --> 00:38:03,319
Speaker 1: only four hundred and sixty six million years ago, when

805
00:38:03,320 --> 00:38:06,960
Speaker 1: scientists think the Earth might have temporarily had a ring system.

806
00:38:07,280 --> 00:38:09,560
Speaker 2: Oh man, all right, what catastrophic thing happened to make

807
00:38:09,560 --> 00:38:10,040
Speaker 2: that happen.

808
00:38:10,160 --> 00:38:12,319
Speaker 1: So what we do know and has been well established,

809
00:38:12,760 --> 00:38:14,839
Speaker 1: is that around four hundred and sixty six million years

810
00:38:14,880 --> 00:38:17,920
Speaker 1: ago there was a time of heavy bombardment. It's the

811
00:38:18,000 --> 00:38:21,680
Speaker 1: Ordovician period of the Earth. And we know from fossil

812
00:38:21,760 --> 00:38:24,279
Speaker 1: records and from other crazy pieces of evidence we have

813
00:38:24,719 --> 00:38:26,640
Speaker 1: that there was just a lot of impacts on Earth.

814
00:38:27,120 --> 00:38:29,239
Speaker 1: Like there are these quarries in Sweden where you like

815
00:38:29,280 --> 00:38:32,600
Speaker 1: dig down to get limestone. Each layer is older and older,

816
00:38:32,800 --> 00:38:35,000
Speaker 1: and there's a layer that corresponds to this time period

817
00:38:35,360 --> 00:38:39,080
Speaker 1: with all these fossil meteorites in it. Like they found

818
00:38:39,080 --> 00:38:41,640
Speaker 1: these weird green rocks down there. They're like, what is this,

819
00:38:41,719 --> 00:38:45,120
Speaker 1: and you find them in this one particular strand, and

820
00:38:45,160 --> 00:38:47,560
Speaker 1: they dug into them and discovered these are meteorites. You

821
00:38:47,600 --> 00:38:50,320
Speaker 1: can tell like chemically and also from the shape of

822
00:38:50,360 --> 00:38:52,680
Speaker 1: these things that they are meteorites are not just like

823
00:38:52,840 --> 00:38:55,840
Speaker 1: rocks from Earth. And then they found similar impact sites

824
00:38:56,080 --> 00:38:58,840
Speaker 1: in other places around the Earth. That tells us like, wow,

825
00:38:58,880 --> 00:39:01,400
Speaker 1: there was a period here, like the weather was bad

826
00:39:01,560 --> 00:39:02,080
Speaker 1: on Earth.

827
00:39:02,239 --> 00:39:04,839
Speaker 2: So it's the idea then that there was something that

828
00:39:04,880 --> 00:39:07,799
Speaker 2: got within the roach limit and it got broken up

829
00:39:07,880 --> 00:39:11,960
Speaker 2: into a ring and then it fell all over the planet.

830
00:39:12,040 --> 00:39:14,000
Speaker 2: And that's why there's a lot of it.

831
00:39:14,120 --> 00:39:16,440
Speaker 1: Yes, So the theory used to be that there was

832
00:39:16,600 --> 00:39:21,160
Speaker 1: probably some impact between asteroids out in the asteroid belt

833
00:39:21,360 --> 00:39:24,040
Speaker 1: or near Jupiter or something that created a lot of

834
00:39:24,040 --> 00:39:27,200
Speaker 1: shrapnel and then the Earth basically flew through a cloud

835
00:39:27,239 --> 00:39:29,759
Speaker 1: of this shrapnel. That was the original idea. So we

836
00:39:29,920 --> 00:39:31,680
Speaker 1: know that there was a lot of impacts. You see

837
00:39:31,680 --> 00:39:33,920
Speaker 1: them all over the planet. There's even evidence of like

838
00:39:34,040 --> 00:39:37,600
Speaker 1: enhanced seismic and tsunami activity from all this time ago.

839
00:39:37,640 --> 00:39:40,799
Speaker 1: It's incredible what you can learn from geology from like

840
00:39:41,120 --> 00:39:43,480
Speaker 1: seeing these fragments of rock that got broken up and

841
00:39:43,520 --> 00:39:45,960
Speaker 1: stuck back together. In ways you only get from like

842
00:39:46,080 --> 00:39:50,239
Speaker 1: really cataclysmic tsunamis and seismic events. Anyway, the theory used

843
00:39:50,239 --> 00:39:53,040
Speaker 1: to be, Okay, there's a cloud of stuff that's created

844
00:39:53,120 --> 00:39:55,840
Speaker 1: far from Earth, and the Earth flies through this cloud

845
00:39:56,080 --> 00:40:00,120
Speaker 1: which creates all these impacts. Right. But a recent study

846
00:40:00,200 --> 00:40:04,239
Speaker 1: they analyzed where on the surface these craters were and

847
00:40:04,320 --> 00:40:08,440
Speaker 1: they discovered that there were suspiciously all along the equator.

848
00:40:08,840 --> 00:40:10,680
Speaker 1: That suggests that there was time for this thing to

849
00:40:10,760 --> 00:40:14,080
Speaker 1: form into a ring around the Earth. And probably your

850
00:40:14,160 --> 00:40:17,840
Speaker 1: description was more accurate that some big thing came pretty

851
00:40:17,880 --> 00:40:20,960
Speaker 1: close to the Earth within its roach limit, was then

852
00:40:21,080 --> 00:40:25,120
Speaker 1: torn apart into bits, which orbited for a while formed

853
00:40:25,120 --> 00:40:29,040
Speaker 1: a ring before the atmosphere dragged it down into impacts

854
00:40:29,080 --> 00:40:29,640
Speaker 1: on Earth.

855
00:40:29,719 --> 00:40:32,320
Speaker 2: Oh my gosh, So was there an extinction that happened

856
00:40:32,360 --> 00:40:33,040
Speaker 2: concurrent with this?

857
00:40:33,480 --> 00:40:37,400
Speaker 1: There is a moment called the Great Order Vision biodiversification event,

858
00:40:37,800 --> 00:40:40,279
Speaker 1: and there was definitely a change in the Earth's temperature.

859
00:40:40,560 --> 00:40:42,319
Speaker 1: If you look at the temperature records, they call this

860
00:40:42,400 --> 00:40:45,319
Speaker 1: a global ice house. It's like a big dip in

861
00:40:45,400 --> 00:40:48,279
Speaker 1: the history of the temperature on Earth. And so this

862
00:40:48,360 --> 00:40:50,879
Speaker 1: paper suggests, oh, this could explain that as well, because

863
00:40:50,920 --> 00:40:53,760
Speaker 1: if you have a huge ring that forms over the equator.

864
00:40:53,800 --> 00:40:56,880
Speaker 1: It's going to significantly shade the planet. And this is

865
00:40:56,920 --> 00:40:59,200
Speaker 1: a really hard study to do because if you want

866
00:40:59,200 --> 00:41:01,760
Speaker 1: to think about where these things land on the Earth,

867
00:41:02,040 --> 00:41:05,160
Speaker 1: you have to know where that land was at the time.

868
00:41:05,520 --> 00:41:08,360
Speaker 1: Right continents move, and you might be thinking, hold on,

869
00:41:08,400 --> 00:41:10,760
Speaker 1: didn't Daniel say there were a bunch of fossil meteors

870
00:41:10,760 --> 00:41:14,280
Speaker 1: that landed in Sweden? And Sweden isn't close to the equator. Yeah,

871
00:41:14,400 --> 00:41:17,320
Speaker 1: it isn't today, but four hundred and sixty six million

872
00:41:17,400 --> 00:41:20,680
Speaker 1: years ago it actually was. So what they had to

873
00:41:20,719 --> 00:41:23,160
Speaker 1: do was figure out where are all these craters that

874
00:41:23,200 --> 00:41:26,560
Speaker 1: you can associate with this time period, which isn't always

875
00:41:26,640 --> 00:41:28,960
Speaker 1: easy because sometimes you can date these things very well.

876
00:41:29,000 --> 00:41:32,319
Speaker 1: Sometimes you can't because the layers therein Then they had

877
00:41:32,360 --> 00:41:35,719
Speaker 1: to rewind the history of the Earth to understand where

878
00:41:35,719 --> 00:41:39,120
Speaker 1: were these craters when the impact actually happened. And so

879
00:41:39,160 --> 00:41:43,160
Speaker 1: they computed this amazing word. I love this, the paleo latitude,

880
00:41:43,480 --> 00:41:47,040
Speaker 1: right like, where on the Earth was this when it happened?

881
00:41:47,080 --> 00:41:47,880
Speaker 1: I love that.

882
00:41:47,880 --> 00:41:50,600
Speaker 2: That's a good word. So those people should be in

883
00:41:50,680 --> 00:41:51,800
Speaker 2: charge of naming the rings.

884
00:41:53,080 --> 00:41:57,160
Speaker 1: Yes, exactly. Riot Sometimes you hear words and signs. You're like, Okay,

885
00:41:57,200 --> 00:42:03,000
Speaker 1: that's well done, that's nice, and that's nice. And so

886
00:42:03,440 --> 00:42:06,080
Speaker 1: they did this calculation. They found all these things, but

887
00:42:06,200 --> 00:42:08,359
Speaker 1: you know, we're talking about a handful of things, not

888
00:42:08,400 --> 00:42:11,920
Speaker 1: like millions of examples. They have like a couple of dozen,

889
00:42:12,200 --> 00:42:16,120
Speaker 1: maybe three dozen craters that they can definitively pinpoint are

890
00:42:16,200 --> 00:42:19,880
Speaker 1: from the Ordovician period, and so you might wonder, like, well,

891
00:42:19,880 --> 00:42:21,880
Speaker 1: how do you really know these are within the equator.

892
00:42:21,880 --> 00:42:24,520
Speaker 1: It's not like they all line up perfectly on the equator.

893
00:42:24,719 --> 00:42:27,520
Speaker 1: They're sort of like loosely associated with the equator. Their

894
00:42:27,600 --> 00:42:31,680
Speaker 1: paleo latitude tends to be less than thirty degrees. And

895
00:42:31,760 --> 00:42:34,520
Speaker 1: so they did a pretty robust statistical analysis. I've read

896
00:42:34,560 --> 00:42:38,160
Speaker 1: this paper carefully because honestly, I'm kind of skeptical about

897
00:42:38,160 --> 00:42:40,480
Speaker 1: the ability of lots of folks out there to do

898
00:42:40,560 --> 00:42:43,560
Speaker 1: statistics in a robust way, because not that many people

899
00:42:43,640 --> 00:42:46,640
Speaker 1: really understand statistics. And I've been shocked to read papers

900
00:42:46,640 --> 00:42:49,879
Speaker 1: in other fields, especially biology, and be like, hmm, I'm

901
00:42:49,880 --> 00:42:52,440
Speaker 1: pretty sure that statistical analysis is totally wrong.

902
00:42:53,440 --> 00:42:54,920
Speaker 2: But I'll give you that.

903
00:42:56,280 --> 00:42:57,799
Speaker 1: But I read this paper. I thought they did a

904
00:42:57,800 --> 00:43:00,719
Speaker 1: great job. They thought about, like, what are the chances

905
00:43:00,840 --> 00:43:05,520
Speaker 1: of getting this kind of distribution of paleo latitudes if

906
00:43:05,560 --> 00:43:08,359
Speaker 1: things actually were evenly spread, And they did some good

907
00:43:08,400 --> 00:43:11,560
Speaker 1: calculations and some good simulations. They look, for example, at

908
00:43:11,560 --> 00:43:14,160
Speaker 1: the distribution of modern impacts and show that they're much

909
00:43:14,200 --> 00:43:18,040
Speaker 1: more broadly distributed than these, So they calculate it's very

910
00:43:18,120 --> 00:43:21,680
Speaker 1: unlikely that these things, by random chance just happened to

911
00:43:21,680 --> 00:43:24,960
Speaker 1: fall along the equator, and that suggests that they probably

912
00:43:24,960 --> 00:43:27,480
Speaker 1: were in a ring above the Earth for a while.

913
00:43:27,840 --> 00:43:30,720
Speaker 1: This is four hundred and sixty six million years ago.

914
00:43:31,040 --> 00:43:33,520
Speaker 1: They also looked at some of these rocks, these actual

915
00:43:33,560 --> 00:43:37,440
Speaker 1: fossil metiors, and they can study the chemical composition of

916
00:43:37,480 --> 00:43:41,839
Speaker 1: these things and understand how much space radiation they were

917
00:43:41,880 --> 00:43:45,640
Speaker 1: exposed to. This is super awesome, yeah, because you know,

918
00:43:45,640 --> 00:43:47,600
Speaker 1: there's a lot more radiation out in space than there

919
00:43:47,640 --> 00:43:49,560
Speaker 1: is here on Earth. Because out in space you don't

920
00:43:49,600 --> 00:43:53,040
Speaker 1: have the benefit of our atmosphere protecting you, and so like,

921
00:43:53,040 --> 00:43:55,799
Speaker 1: there are all these high speed particles, cosmic rays and

922
00:43:55,840 --> 00:43:59,760
Speaker 1: solar wind constantly penetrating it, and that changes the chemical

923
00:44:00,120 --> 00:44:03,160
Speaker 1: position of stuff, right. It matches into the rocks, it

924
00:44:03,200 --> 00:44:07,000
Speaker 1: degrades some of those isotopes, so you can basically count

925
00:44:07,080 --> 00:44:09,920
Speaker 1: how long something has been in space by looking at

926
00:44:09,960 --> 00:44:13,480
Speaker 1: the chemical makeup of a rock, and it looks like

927
00:44:13,560 --> 00:44:16,760
Speaker 1: these rocks were not exposed to space for very long,

928
00:44:17,040 --> 00:44:20,960
Speaker 1: only like a few tens of thousands of years, not millions,

929
00:44:21,320 --> 00:44:23,839
Speaker 1: and that means that probably they were like on the

930
00:44:23,880 --> 00:44:27,280
Speaker 1: inside of some large asteroid for many, many, many millions

931
00:44:27,360 --> 00:44:30,480
Speaker 1: or billions of years, basically protected from the radiation of space,

932
00:44:31,000 --> 00:44:34,080
Speaker 1: then torn apart by the Earth's tidal forces into a

933
00:44:34,120 --> 00:44:36,560
Speaker 1: bunch of little rocks which were not protected by the

934
00:44:36,640 --> 00:44:38,920
Speaker 1: radiation of space, but only for a few tens of

935
00:44:38,920 --> 00:44:41,400
Speaker 1: thousands of years before they fell to the surface of

936
00:44:41,400 --> 00:44:44,960
Speaker 1: the Earth and then protected again. So you know they

937
00:44:44,960 --> 00:44:48,120
Speaker 1: were near the surface of an asteroid out in space,

938
00:44:48,239 --> 00:44:51,120
Speaker 1: exposed to radiation for only a few tens of thousands

939
00:44:51,200 --> 00:44:54,400
Speaker 1: of years, So that's also suggestive. None of this is

940
00:44:54,440 --> 00:44:57,880
Speaker 1: completely conclusive, but you know, this is like solving a mystery.

941
00:44:58,120 --> 00:45:00,640
Speaker 1: You have a few clues you're trying to piece together story.

942
00:45:00,760 --> 00:45:03,000
Speaker 1: All this is very circumstantial, but it all points in

943
00:45:03,040 --> 00:45:03,720
Speaker 1: the same direction.

944
00:45:03,960 --> 00:45:06,960
Speaker 2: You mentioned that there was like a shrapnel theory. Wouldn't

945
00:45:06,960 --> 00:45:10,880
Speaker 2: the shrapnel theory also have something big where most of

946
00:45:10,920 --> 00:45:13,479
Speaker 2: it was protected by space radiation, and then it got

947
00:45:13,719 --> 00:45:16,200
Speaker 2: broken into pieces, and those pieces worked both to space

948
00:45:16,280 --> 00:45:18,960
Speaker 2: radiation for a short period of time before Earth hit it.

949
00:45:19,239 --> 00:45:21,360
Speaker 2: How would you tell the difference between those two options?

950
00:45:21,760 --> 00:45:24,480
Speaker 1: Yes, a short period of time, but longer, like if

951
00:45:24,520 --> 00:45:26,719
Speaker 1: there was a collision out on the asteroid belts that

952
00:45:26,760 --> 00:45:29,360
Speaker 1: created all this shrapnel, it would take much longer to

953
00:45:29,400 --> 00:45:32,720
Speaker 1: get to Earth, probably millions of years, not just ten thousand,

954
00:45:33,280 --> 00:45:35,280
Speaker 1: and so that's how they can tell the difference.

955
00:45:35,400 --> 00:45:37,399
Speaker 2: Got it. That's very cool. Who was the first author

956
00:45:37,440 --> 00:45:39,200
Speaker 2: in this study? Let's give them some credit? This sounds

957
00:45:39,200 --> 00:45:42,320
Speaker 2: awesome as scientists who understand statistics.

958
00:45:42,600 --> 00:45:46,040
Speaker 1: Yeah, so this is Andrew Tompkins, Aaron Martin, and Peter

959
00:45:46,239 --> 00:45:49,719
Speaker 1: Kaywood and a paper in Earth and Planetary Studies in

960
00:45:49,760 --> 00:45:53,920
Speaker 1: November twenty twenty four. It's really quite readable, even for

961
00:45:54,120 --> 00:45:57,320
Speaker 1: somebody outside their field. So congrats on the exciting result

962
00:45:57,480 --> 00:45:58,720
Speaker 1: and the nicely written paper.

963
00:45:58,760 --> 00:46:00,799
Speaker 2: And where did you come across this? How did we

964
00:46:00,840 --> 00:46:02,080
Speaker 2: come to talk about this today?

965
00:46:02,440 --> 00:46:04,680
Speaker 1: I think a bunch of listeners might have heard press

966
00:46:04,719 --> 00:46:07,239
Speaker 1: releases about it and send me an email asking me

967
00:46:07,320 --> 00:46:09,440
Speaker 1: to explain it. So I put it on my list,

968
00:46:09,520 --> 00:46:12,840
Speaker 1: and eventually I actually do get to everything on my list,

969
00:46:12,920 --> 00:46:15,600
Speaker 1: as I promise, but we got along backlog, so it

970
00:46:15,680 --> 00:46:17,920
Speaker 1: might take me a while. But if you are curious

971
00:46:18,160 --> 00:46:20,200
Speaker 1: about something you've heard about in the news and you'd

972
00:46:20,239 --> 00:46:22,319
Speaker 1: like for us to break it down and explain it

973
00:46:22,360 --> 00:46:24,840
Speaker 1: to you, for Kelly to ask me hard questions, for

974
00:46:24,920 --> 00:46:28,600
Speaker 1: me to ask Kelly naive biology questions, then please send

975
00:46:28,640 --> 00:46:31,200
Speaker 1: us your questions. We'd love to dig into something you'd

976
00:46:31,200 --> 00:46:32,400
Speaker 1: like to hear more about.

977
00:46:32,239 --> 00:46:35,200
Speaker 2: So write us at question I always forget our email address.

978
00:46:35,280 --> 00:46:36,160
Speaker 2: What's our email address?

979
00:46:36,200 --> 00:46:39,520
Speaker 1: Daniel Questions at Daniel and Kelly dot org. You can

980
00:46:39,520 --> 00:46:41,120
Speaker 1: write to us and ask us like, what is our

981
00:46:41,160 --> 00:46:41,840
Speaker 1: email address?

982
00:46:42,400 --> 00:46:44,799
Speaker 2: Yes you probably I can be super successful on that one,

983
00:46:44,800 --> 00:46:46,359
Speaker 2: but good luck and we hope to hear.

984
00:46:46,320 --> 00:46:49,120
Speaker 1: From you until next time. Put a ring on it.

985
00:46:49,160 --> 00:46:54,360
Speaker 2: That's right. My daughter would be absolutely appalled if I

986
00:46:54,400 --> 00:46:56,600
Speaker 2: say so. Anyway, Thanks everyone.

987
00:46:56,400 --> 00:46:57,239
Speaker 1: Tune in next time.

988
00:47:04,320 --> 00:47:08,160
Speaker 2: Daniel and Kelly's Extraordinary Universe is produced by iHeartRadio. We

989
00:47:08,200 --> 00:47:10,600
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990
00:47:10,760 --> 00:47:13,520
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991
00:47:13,719 --> 00:47:15,400
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992
00:47:15,520 --> 00:47:18,480
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993
00:47:18,480 --> 00:47:21,480
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994
00:47:21,520 --> 00:47:21,920
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995
00:47:22,160 --> 00:47:25,640
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996
00:47:25,680 --> 00:47:28,520
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997
00:47:28,320 --> 00:47:30,200
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998
00:47:30,239 --> 00:47:34,120
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999
00:47:34,160 --> 00:47:36,480
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1000
00:47:36,880 --> 00:47:37,880
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1001
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