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Speaker 1: Ay, Katie, what's the weather going to be like tomorrow?

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Speaker 1: And you're part of Italy, let me check. It says

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Speaker 1: it's going to be sunny with a chance of meatballs,

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Speaker 1: and you believe in that, or the weather prediction is

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Speaker 1: pretty reliable over there, not really. We're kind of near

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Speaker 1: the Alps and that seems to scramble whatever weather radar

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Speaker 1: that they use, So sometimes you plan a picnic and

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Speaker 1: sometimes you get meat balled on. It's sure would be

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Speaker 1: nice if the weather was more reliable, like it was

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Speaker 1: just a pattern and it repeated, like you could sort

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Speaker 1: of schedule the rain at like two pm and then

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Speaker 1: at three o'clock you get some snow. That would be awesome.

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Speaker 1: Or you know, you could also just try my strategy.

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Speaker 1: What's that? Just moved to a place where there isn't

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Speaker 1: any weather. It's just sunny every day. So essentially you're

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Speaker 1: going to move to the moon. Sometimes southern California does

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Speaker 1: feel like the moon? Is it because of all the

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Speaker 1: people just as alien? It's because of all the people

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Speaker 1: acting like aliens. Hi, I'm Daniel. I'm a particle physicist

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Speaker 1: and a professor at UC Irvine in Southern California, and

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Speaker 1: I definitely do appreciate the sunshine. My name is Katie.

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Speaker 1: I'm the host of Creature Feature and Animals podcast. I

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Speaker 1: live in northern Italy and I do appreciate that our

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Speaker 1: weather is mainly like pasta and pesto based. And I

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Speaker 1: know we're joking around, but is there an expression in

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Speaker 1: Italian that's something like a cloudy with a chance of meatballs?

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Speaker 1: Or is that a purely American thing? I think that's

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Speaker 1: pretty American. In fact, meatballs are not so much of

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Speaker 1: a thing in Italy. It's as much of the iconic

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Speaker 1: Italian food as it seems in the US that is

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Speaker 1: more kind of an Americanized version of Italy. So it's

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Speaker 1: neither on our plates nor in our weather. So there's

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Speaker 1: no like strange weather event that would make Italians say

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Speaker 1: it's raining meatballs, huge pieces of hail or something not

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Speaker 1: that I know of. Now, well, welcome to the podcast.

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Speaker 1: Daniel and Jorge explain the Universe, in which we examine

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Speaker 1: all of the crazy and amazing and surprising things that

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Speaker 1: the universe does. We dig into whether it all makes

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Speaker 1: sense and whether it can be predicted, whether we can

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Speaker 1: find simple scientific, mathematical stories that explain all of the

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Speaker 1: amazing things that the universe does, from compressing matter the

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Speaker 1: hearts of black holes, to whizzing corks and gluons together

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Speaker 1: inside neutron stars, to causing all of the weather patterns

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Speaker 1: on Earth, to maybe even wiping out huge parts of

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Speaker 1: life on the planet. This sounds fun. We try to

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Speaker 1: be an uplifting podcast as usual, though we don't shy

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Speaker 1: away from facing the truth and from accepting our ignorance

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Speaker 1: of it. My friend and usual co host Orge can't

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Speaker 1: be here today, but I'm very glad to be joined

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Speaker 1: by one of our regular co host Katie. Katie, thanks

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Speaker 1: again for joining us. Yeah. Absolutely. I noticed Jorge is

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Speaker 1: suspiciously absent the day we're talking about asteroid impacts, and

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Speaker 1: I gotta ask, does he got a secret space ship?

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Speaker 1: Maybe he's the one causing the asteroid impacts, you know,

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Speaker 1: he's the one dropping these things on the planet. Has

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Speaker 1: Jorge ever been in the same room with you as

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Speaker 1: the asteroid. No, but it does seem like sometimes he

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Speaker 1: does want to wipe everything out. But I love thinking

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Speaker 1: about the long history of life on Earth. You know,

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Speaker 1: we are curious beings. We look around ourselves here on

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Speaker 1: the planet. We wonder how do we get here? How

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Speaker 1: did the Earth end up to be this way and

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Speaker 1: not some other way? And one of the more fascinating

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Speaker 1: things about the history of life on Earth is how

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Speaker 1: much it hinges on certain tipping points, specific moments in history,

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Speaker 1: which if they had gone another way, we might not

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Speaker 1: be here, or we might look totally different, or we

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Speaker 1: might have to there's or three heads. It's fun to

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Speaker 1: imagine alternative earths. If you had run this experimental universe

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Speaker 1: many times and had different earths, what would life on

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Speaker 1: Earth look like at this point? Would there still be dinosaurs?

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Speaker 1: Would we all be huge intelligent ladybugs. It's fun to

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Speaker 1: imagine all the different varieties and what chance there was

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Speaker 1: for us to actually get here. I love the idea

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Speaker 1: of being huge intelligent ladybugs. I think we'd need a

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Speaker 1: lot more oxygen for that, But I think we would

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Speaker 1: also look much more fashionable. Do you think ladybugs, if

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Speaker 1: they developed intelligence and technology, would also develop clothing. I mean,

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Speaker 1: because they already look good naked. They already looked pretty fantastic.

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Speaker 1: But I can't imagine some sort of fashion revolution of

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Speaker 1: a ladybug who dares to wear stripes instead of thoughts

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Speaker 1: the Ladybug Fashion Podcast. Pretty controversial stuff, but it is

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Speaker 1: part of our job here, not just to understand what

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Speaker 1: are the basic rules of the universe. How do the

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Speaker 1: tiny particles come together and we've our reality out of

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Speaker 1: little corks and gluons and electrons or whatever other particles

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Speaker 1: might be out there. How does the dark matter shape

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Speaker 1: the formation of the universe. We also like to think

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Speaker 1: about the formation of life here on Earth and what

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Speaker 1: happened to create this story, What exactly led to us

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Speaker 1: being here having a podcast that isn't hosted by two ladybugs.

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Speaker 1: I mean, in a way, we are feasting on the

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Speaker 1: bones of dinosaurs because by their mass death came the

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Speaker 1: rise of mammals, and we are mammals, So we can

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Speaker 1: thank a dead dinosaur for being here, I think, in

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Speaker 1: my opinion, do you think that's like the best example

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Speaker 1: of inherited privilege ever? You know, It's like, we're not

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Speaker 1: responsible for the dinosaur's extinction directly, but we're definitely benefiting

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Speaker 1: from the fact that they were wiped out. Are you

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Speaker 1: saying that some kind of very early prehistoric shrew was

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Speaker 1: colluding with the asteroid and saying make it look like

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Speaker 1: an accident It certainly does seem convenient, right, you know,

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Speaker 1: when we benefit from the kinds of things. Well, hopefully

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Speaker 1: the dinosaurs of today, that is, birds will not sue us.

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Speaker 1: Statute of limitations is long, long, long expired. And one

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Speaker 1: fascinating thing about the history of life on Earth is

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Speaker 1: that it is punctuated with these mass extinctions. It's not

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Speaker 1: just the asteroid that hit the Earth that probably wiped

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Speaker 1: out the dinosaurs that created a new flowering of mammals.

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Speaker 1: There many times in the history of life on Earth

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Speaker 1: when there were these wipeout events where a huge fraction

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Speaker 1: of life on Earth was killed, making room for new developments,

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Speaker 1: new explorations of the evolutionary tree by the remaining life.

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Speaker 1: And it's interesting to think about how each of these

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Speaker 1: contribute to us being here today. Right, If all of

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Speaker 1: those hadn't gone exactly the way that they went, we

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Speaker 1: wouldn't be here talking about it. Maybe we wouldn't even

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Speaker 1: be any intelligent life on Earth. It would just be

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Speaker 1: a bunch of dumb dinosaurs ting on each other and

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Speaker 1: nibbling on plants, right, I mean, it's just hard to

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Speaker 1: know where things would have been. I mean, as you said,

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Speaker 1: like when there is a die off of animals, there

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Speaker 1: is an opportunity as long as the earth is still

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Speaker 1: habitable for a new kind of group, a resurgence of

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Speaker 1: species who otherwise would not be able to really thrive

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Speaker 1: because they'd be out competed by the animals that went extinct.

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Speaker 1: So it's hard to imagine, you know, if dinosaurs hadn't

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Speaker 1: died off, you know, maybe there would not have been

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Speaker 1: evolutionary pressure for any one species to become as intelligent

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Speaker 1: as humans. Maybe it would have been too dangerous a

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Speaker 1: life for primates to have been able to come to power.

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Speaker 1: It's just it's so hard to know. Of course, you know,

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Speaker 1: we could have also just been like two dinosaurs now

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Speaker 1: talking about stuff on the podcast, talking about like what

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Speaker 1: if we had gone extinct because of an asteroid? Would

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Speaker 1: some of those little shrews turned into weird pink things? Yea, exactly.

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Speaker 1: And I think there's something really interesting that you brought

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Speaker 1: up there that's not widely enough appreciated, which is the

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Speaker 1: importance of randomness and opportunity in evolution. You know, some

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Speaker 1: people feel like evolution is this transformation where species develop

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Speaker 1: into more and more advanced versions of themselves. But you know,

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Speaker 1: there's really a randomness there, Like how does the species

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Speaker 1: change from generation to generation. It's from like changes in

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Speaker 1: the genetic code, which comes from transcription errors or cosmic rays.

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Speaker 1: There's no design here. It's really just like a random

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Speaker 1: walk through genetic space. Right, It's like throwing a bunch

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Speaker 1: of dice to see what your kids are going to be. Like, yeah,

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Speaker 1: I mean, so evolution doesn't have a game plan. I

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Speaker 1: think that's one of the most important things to understand

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Speaker 1: is evolution is not this like efficient force perfecting things

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Speaker 1: into their most like quote unquote perfect forms. It's just

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Speaker 1: a very simple rule. If something survives and passes on

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Speaker 1: its genetic information, hooray, it's survived and passed on its

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Speaker 1: genetic information to the next that's it. That is absolutely it.

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Speaker 1: And for that extremely simple rule, you get incredibly marvelous complexity.

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Speaker 1: So there are a lot of things that can happen.

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Speaker 1: It's not just the random mutation of DNA. It's the

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Speaker 1: reshuffling of DNA. Right, you have like mate choice, what

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Speaker 1: happens there, And then it's the environment, like what happens

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Speaker 1: with your environment. There can be random changes in the

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Speaker 1: environment that leads to selective pressures, to extinction events, two

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Speaker 1: changes in related species that then causes the other species

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Speaker 1: to have to evolve. So there's so many factors that

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Speaker 1: go into evolution that from this incredibly simple rule just

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Speaker 1: like if you can pass on your DNA, yeah you

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Speaker 1: did it. You passed on your DNA, and then the

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Speaker 1: next generation gets a shot at that. That has turned

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Speaker 1: into just this incredibly immensely complex and convoluted situation with

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Speaker 1: life on Earth, where sometimes an animal will have weird

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Speaker 1: features that we try to look at, we think, what

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Speaker 1: is this, what is the thing? Why did they evolve it?

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Speaker 1: And it just turns out it's this weird artifact of

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Speaker 1: earlier evolution or something like you know, we have this

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Speaker 1: appendix and it's kind of mysterious. What does it do.

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Speaker 1: We're not really sure if it has much of a

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Speaker 1: purpose for us. But it's not like evolution has that

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Speaker 1: foresight of like, well, I better take this appendix out

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Speaker 1: because they're not really going to need it that much

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Speaker 1: as modern humans. So like, it's not an intelligent designer.

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Speaker 1: It's kind of just improv all the time. I think

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Speaker 1: that's a really fascinating aspect of it, not just that

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Speaker 1: there's a randomness there, but that it's so tightly linked

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Speaker 1: to the environment in which this exploration is happening. Right,

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Speaker 1: It's really a reflection. It's like a mirroring of the

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Speaker 1: situation that doing the selection because one animal might survive

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Speaker 1: very well in one context and just die off rapidly

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Speaker 1: in another, and so the animals, the life we have

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Speaker 1: here on Earth is a reflection of the selection pressure

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Speaker 1: which comes from the environment in which we live, of course, right,

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Speaker 1: But that goes also backwards in time. As you say,

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Speaker 1: it's like it's telling story of the selection pressure over time.

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Speaker 1: Every species that survives has survived through changing environments. Right,

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Speaker 1: Things were colder and then they were hotter, and in in

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Speaker 1: order to get here, you have to manage all of

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Speaker 1: those changes somehow. It's your population grows and evolves and

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Speaker 1: gains hair and lose his hair and all that kind

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Speaker 1: of stuff. So I think it's really fascinating that not

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Speaker 1: only does the earth itself tell the histories you like,

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Speaker 1: dig down through the layers and see layers of rock

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Speaker 1: and events that have happened through the history, but life

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Speaker 1: on Earth also carries with it the history of its evolution. Right,

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Speaker 1: As you say, why do you have this vestigial bid. Oh, well,

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Speaker 1: we needed that millions of years ago, and we're still

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Speaker 1: getting rid of it due to the new pressure. So

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Speaker 1: I think that's super fascinating to look at the history

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Speaker 1: of life on Earth, And to me, that's one of

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Speaker 1: the most important things about science is answering this question,

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Speaker 1: like how did we get here? What is the story

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Speaker 1: of us? It tells us sort of how to live

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Speaker 1: our lives and who we are, and in some sense,

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Speaker 1: you know, as much as science can, it tells us

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Speaker 1: why we're here at least what happened before we got here. Yeah,

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Speaker 1: And I think it's so interesting because our life spans

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Speaker 1: are relatively short compared to the universe, even compared to

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Speaker 1: our own Earth. So our perception of what is stable, right,

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Speaker 1: like what stable species are existence is warped by our

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Speaker 1: you know, relatively short lifespans, and so we have this

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Speaker 1: sense of things are as they are. Giraffes have always existed,

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Speaker 1: We've always existed, but that's really not the case. And

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Speaker 1: you know, when we look at some of these animals

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Speaker 1: that have gone extinct and we think, like, wow, how

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Speaker 1: could something that's strange have existed? Well, maybe hopefully if

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Speaker 1: we're still alive, and like a thousand years. Potentially some

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Speaker 1: species like the panda that's highly specialized to eat massive

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Speaker 1: if there's an environmental change, you know, we might look

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Speaker 1: back and say, like, how could such a silly animal

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Speaker 1: have existed where it's entire diet is dependent on bamboo

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Speaker 1: and they're really bad at mating in captivity. I think

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Speaker 1: we have this very narrow view in our own lifespan,

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Speaker 1: so it is it becomes kind of fascinating when we

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Speaker 1: and you're like, oh, yeah, we're just like little babies,

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Speaker 1: Like we're a little baby species. Yeah. And it's hard

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Speaker 1: for us because we tend to think in time scales

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Speaker 1: took us a long time to appreciate how old the

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Speaker 1: Earth was. The first hints we had that it might

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Speaker 1: be billions of years old blew people's minds because it

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Speaker 1: was just such a strange concept. Understanding geological processes like

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Speaker 1: the formations of the continents and like glaciation work hard

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Speaker 1: for people because we don't tend to think in sort

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Speaker 1: of deep time, and yet we know that these processes

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Speaker 1: really do shape and influence the nature of the world

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Speaker 1: in which we live. And maybe most interesting and most

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Speaker 1: dramatic are the cataclysmic events, right is where if the

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Speaker 1: asteroid it hits somewhere different, maybe the dinosaurs wouldn't have

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Speaker 1: wiped out. Or if dinosaur scientists had looked up in

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Speaker 1: the sky and seen it coming and developed technology too diverted,

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Speaker 1: you know, then maybe things really would be different. I

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Speaker 1: love those moments when history could really take lots of

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Speaker 1: different courses. Yeah, dinosaur Matt Damon and a dinosaur Jennifer

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Speaker 1: Lawrence trying to figure things out. I wonder if the

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Speaker 1: dinosaur version of that movie would have been any better. Yeah,

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Speaker 1: I mean it is that. I do think about those

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Speaker 1: cataclysmic events quite a bit, you know, just the our

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Speaker 1: vulnerability of you know, as a single human, were relatively

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Speaker 1: vulnerable in our little fleshy bodies, but then our planet

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Speaker 1: also feels somewhat vulnerable just this like little paradise of

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Speaker 1: being able to be alive on it in a pretty

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Speaker 1: unforgiving universe. And then just that rock just traveling along

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Speaker 1: randomly could just you know, spell the end for an

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Speaker 1: entire planet of species. It's somewhat terrifying right to know

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Speaker 1: that these rocks are out there, and if one of

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Speaker 1: them falls into the gravity well of the Earth, it

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Speaker 1: could end all life on Earth, or some lives on Earth.

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Speaker 1: It certainly would not be a good day. And as

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Speaker 1: we saw in the nineties, these kind of things do happen,

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Speaker 1: like comic Shoemaker Levy, which came into the Solar System

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Speaker 1: smashed into Jupiter, creating fireballs bigger than planet Earth. So

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Speaker 1: this is not only something that happens than the deep

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Speaker 1: history of time, it's something that could happen. We don't

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Speaker 1: know when NASA is doing its best to track these asteroids,

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Speaker 1: but beyond that, we wonder, like, is it possible to

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Speaker 1: predict these events far in the future. Is there some

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Speaker 1: sort of like deep time process sort of like glaciation

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Speaker 1: or like formations of the continents which we can't yet

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Speaker 1: imagine because it happens on a galactic scale, which is

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Speaker 1: shaping these asteroid impacts, which is maybe creating patterns that

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Speaker 1: we could understand, which we could use to predict, so

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Speaker 1: we could know. Guys, we only got a million more

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Speaker 1: years before the next wave of killer asteroids. Better start

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Speaker 1: funding those spaceships. Yeah, I mean I'd like to know

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Speaker 1: because if an asteroid's coming in like the next year,

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Speaker 1: I know I can skip a dentist appointment. So don't

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Speaker 1: bother saving for retirement, folks. So on today's episode, we'll

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Speaker 1: be asking the question is there a pattern to major

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Speaker 1: asteroid impacts on Earth? And is it gonna benefit us

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Speaker 1: to know this or just make us scared? You can

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Speaker 1: short the stock market because you know all life on

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Speaker 1: Earth is going so put everything in gold, folks. This

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Speaker 1: is now a financial investment podcast. I believe that's illegal.

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Speaker 1: But also if the asteroid is made out of gold,

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Speaker 1: maybe you shouldn't invest in it because then we will

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Speaker 1: be inundated with gold and then also extremely dead. That's

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Speaker 1: not actual financial advice. Don't sue me. So you're saying

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Speaker 1: that when we're wiped out and the Ladybug civilization rises

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Speaker 1: up in our ashes, they're going to find so much

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Speaker 1: gold everywhere. It's just gonna be like they're paving their

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Speaker 1: streets in gold. Yeah, they're building their little Ladybug toilets

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Speaker 1: out of gold. So what is Ladybug Donald Trump then

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Speaker 1: going to do to make his bathroom extra bling well

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Speaker 1: as usual. I was wondering if people out there had

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Speaker 1: thought about if there was a pattern to major asteroid

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Speaker 1: impacts and if there was something we could do to

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Speaker 1: predict it. So thanks very much to everybody who participates

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Speaker 1: in these off the cuff answers on the virtual street.

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Speaker 1: If you would like to play this role for future episodes,

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Speaker 1: please don't be shy right to me. Two questions at

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Speaker 1: Daniel and Jorge dot com. So think about it for

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Speaker 1: a moment before you hear these answers. Do you think

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Speaker 1: there's a pattern to major asteroid impacts on Earth? Here's

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Speaker 1: what some listeners had to say. I think I heard

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Speaker 1: once it's like every thirty million years or something like that,

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Speaker 1: there's this massive asteroid that crashes into Earth and basically

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Speaker 1: wipes off all of the life on it. But I

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Speaker 1: don't really know. I don't think there's like any sort

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Speaker 1: of pattern to the distribution of asteroids. Those pods will

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Speaker 1: collide with Earth at some point in the post island,

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Speaker 1: so I don't think that there's a pattern of asteroid impacts.

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Speaker 1: It's orbital mechanics. Anything more than two bodies is pretty

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Speaker 1: chaotic and random, but I do think that there is

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Speaker 1: a governing frequency that decreases over time, so as our

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Speaker 1: Earth and Solar system get older, um impacts become less frequent.

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Speaker 1: I think you get some patterns with asteroids, because wouldn't

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Speaker 1: you get kind of like a cyclic almost resonant wave

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Speaker 1: function if you spend things up on a macro scale,

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Speaker 1: just since everything is orbiting, you could kind of mathematically

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Speaker 1: predict when it might fling stuff in our direction. I

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Speaker 1: don't know, well, hopefully if it's a pattern, it will

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Speaker 1: show us that no major asteroid will either art in

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Speaker 1: the future or until we are able to defend ourselves

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Speaker 1: properly to define them, because probably this is the most

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Speaker 1: difficult thing to just to see them in time for

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Speaker 1: us to prepare to do something about it. I really

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Speaker 1: do agree with the person who says that they hope

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Speaker 1: that no asteroid hits Earth until we're ready to defend ourselves,

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Speaker 1: because I feel like if we just learn like in

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Speaker 1: a hundred years we're going to get a big one,

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Speaker 1: but we have no way to do anything about it,

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Speaker 1: that would be a bit of a bomber. I'll be

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Speaker 1: honest with you, what do you mean we have no

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Speaker 1: way to do anything about it. You have no faith

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Speaker 1: in physicists and engineers to save the planet. It depends

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Speaker 1: on how fast you guys are at writing grant proposals.

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Speaker 1: I guess. So, if we've got an asteroid coming in

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Speaker 1: a hundred years, maybe you can do it. But if

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Speaker 1: it's like five weeks, do you think we could do

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Speaker 1: something about it? You know, the key really is to

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Speaker 1: discovering these things early on. If you see far in

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Speaker 1: advance that it's coming, that it only needs a little

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Speaker 1: bit of a push to not hit the Earth. It's

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Speaker 1: sort of like if somebody's firing a sniper shot from

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Speaker 1: five miles away, the tiniest little deviation in the direction

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Speaker 1: of their rifle means they're going to miss their target.

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Speaker 1: And so if you can figure out that this thing

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Speaker 1: is going to come in a hundred years, then even

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Speaker 1: the faintest little push, you could throw a rock at it,

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Speaker 1: or is that it with a laser, and they would

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Speaker 1: miss the Earth. You only have a few weeks of notice.

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Speaker 1: Then it's much much harder. You have to give it

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Speaker 1: a much bigger push. But actually, you know, this week,

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Speaker 1: as we record this episode, NASA is doing an amazing

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Speaker 1: test the dart probe is out there and it's about

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Speaker 1: to push on an asteroid to see if this works.

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Speaker 1: Can we actually find an asteroid and push on it

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Speaker 1: and see if we can change its direction. This is

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Speaker 1: not one that NASA thinks is going to hit the Earth.

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Speaker 1: This is just an experiment to see is it possible

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Speaker 1: to change its trajectory. Also, fortunately it's not one that

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Speaker 1: NASA thinks is going to hit the Earth after they

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Speaker 1: change its traject Right. I was about to say, I

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Speaker 1: really hope they double checked their math and their units,

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Speaker 1: because that would be a heck of all whoop. See

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Speaker 1: that is actually something people worry about developing these tools

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Speaker 1: that can affect the future of the human race. Like

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Speaker 1: if you can now aim asteroids, then you know some

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Speaker 1: super billain might decide to use that to threaten Earth

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Speaker 1: with asteroids. Right. Another direction people are working on is

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Speaker 1: zapping these things with lasers. That sounds like science fiction,

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Speaker 1: but you can get a powerful enough laser and zap

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Speaker 1: one side of the asteroid, then you can like vaporize

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Speaker 1: some of the rock and the ice and it can

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Speaker 1: give it a sideways push so that it doesn't hit

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Speaker 1: the Earth. There, people in Santa Barbara working on these

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Speaker 1: kind of super lasers. But also that does make me

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Speaker 1: worry about you know, like other applications of supers well,

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Speaker 1: like you're not firing this laser from Earth right because

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Speaker 1: I would imagine you'd scorch a few birds and maybe

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Speaker 1: a few planes if you did that. I don't think

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Speaker 1: they even have a prototype of this laser so far.

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Speaker 1: It's still in the exploratory studies. But there are a

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Speaker 1: range of solutions, and we actually have a whole podcast

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Speaker 1: episode about how to defend the Earth from asteroids, including

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Speaker 1: gravity tractors and laser beams and giving them a push.

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Speaker 1: It all depends on what the thing is made out of,

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Speaker 1: Like if it's a pile of rubble, it's kind of

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Speaker 1: hard to give it a push, or if it's a

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Speaker 1: big ball of ice, it's good to zap it with

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Speaker 1: a laser, And also really depends on spotting it early

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Speaker 1: and understanding where it comes from. We're gonna take a

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Speaker 1: quick break, but when we come back, we're going to

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Speaker 1: talk about the source of these deadly rocks that might

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Speaker 1: wipe out life on Earth, whether or not the data

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Speaker 1: suggests there are coming in a pattern, and what we

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Speaker 1: can do about it. So like what angle I should

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Speaker 1: keep my umbrella at. Essentially how many umbrellas you need

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Speaker 1: to buy? Actually, all right, we're back and we're talking

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Speaker 1: about whether there's a pattern to asteroid impact on Earth.

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Speaker 1: We have some pretty strong evidence that about sixty five

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Speaker 1: million years ago there was a huge impact or it

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Speaker 1: was something like five to ten kilometers wide, and it

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Speaker 1: struck the Earth the twenty thousand miles per hour. You

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Speaker 1: might wonder, like, why is it going so fast? Well,

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Speaker 1: most of the stuff out there in the Solar System

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Speaker 1: is whizzing around the Sun pretty fast. It's like we're

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Speaker 1: all the fast land on the freeway, and if somebody

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Speaker 1: comes at you at that speed, it's going to be

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Speaker 1: pretty fast. But also, the Earth has a lot of gravity,

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Speaker 1: so once something comes even near the Earth and then

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Speaker 1: falls to the surface, it gets accelerated by the Earth.

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Speaker 1: The Earth is like pulling it in, so by the

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Speaker 1: time it hits the ground, it has a lot of velocity.

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Speaker 1: And this asteroid impact, we think, wiped out about thirty

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Speaker 1: of the species on Earth at the time, including many

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Speaker 1: of the dinosaurs. Yeah, I mean, I think one of

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Speaker 1: the things that is important to remember is that this

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Speaker 1: did not just wipe out the dinosaurs, only it wiped

430
00:23:45,320 --> 00:23:49,920
Speaker 1: out anything and everything that was around, like a good

431
00:23:50,040 --> 00:23:53,520
Speaker 1: number of them, the things that ended up surviving. It

432
00:23:53,640 --> 00:23:57,840
Speaker 1: was not like a dinosaur seeking asteroid that targeted the

433
00:23:57,880 --> 00:24:01,600
Speaker 1: dinosaurs specifically. It just targeted anything that was not able

434
00:24:01,680 --> 00:24:06,400
Speaker 1: to survive. The fallout of what happened after the asteroid hit.

435
00:24:06,560 --> 00:24:08,199
Speaker 1: I mean, I'm sure there was a good amount of

436
00:24:08,200 --> 00:24:11,000
Speaker 1: death and the immediate aftermath of the asteroid, but a

437
00:24:11,040 --> 00:24:13,399
Speaker 1: lot of it was sort of both long and slow

438
00:24:13,520 --> 00:24:17,439
Speaker 1: drawn out extinction, and the exact causes of it aren't

439
00:24:17,840 --> 00:24:22,640
Speaker 1: precisely known. It's hard to find really accurate evidence of

440
00:24:22,720 --> 00:24:25,560
Speaker 1: what exactly happened. But you know, there are a lot

441
00:24:25,600 --> 00:24:29,959
Speaker 1: of theories about, you know, the ecosystems collapsing because of

442
00:24:30,359 --> 00:24:33,640
Speaker 1: the you know, massive amount of debris that cut out

443
00:24:33,680 --> 00:24:35,800
Speaker 1: the sun, and of course you don't have as much

444
00:24:35,920 --> 00:24:39,119
Speaker 1: vegetation and so you don't have as many big herbivores,

445
00:24:39,320 --> 00:24:42,040
Speaker 1: and then you don't have as many big carnivores. So

446
00:24:42,280 --> 00:24:45,040
Speaker 1: like that. It basically, you know how these ecosystems are

447
00:24:45,080 --> 00:24:48,280
Speaker 1: like these Jenga towers and you pull one thing out

448
00:24:48,320 --> 00:24:50,879
Speaker 1: and it can collapse. Well, like this asteroid hitting is

449
00:24:50,920 --> 00:24:53,520
Speaker 1: like a throwing a tennis ball at the Jenga tower,

450
00:24:53,760 --> 00:24:58,239
Speaker 1: and so only the things that were hardy enough, you know,

451
00:24:58,520 --> 00:25:01,920
Speaker 1: typically quite small as well, because they didn't require as

452
00:25:02,040 --> 00:25:05,719
Speaker 1: much food, we're able to survive. And not all the

453
00:25:05,720 --> 00:25:09,040
Speaker 1: dinosaurs one extinct, like we still have birds. Birds are

454
00:25:09,280 --> 00:25:12,520
Speaker 1: the surviving dinosaurs of this period, and they were small

455
00:25:12,640 --> 00:25:16,400
Speaker 1: enough that they were able to sort of escape the

456
00:25:16,520 --> 00:25:21,040
Speaker 1: uh starvation of these larger dinosaurs that had much more

457
00:25:21,400 --> 00:25:25,000
Speaker 1: intensive dietary needs. And that's, like, I think, to me,

458
00:25:25,160 --> 00:25:27,800
Speaker 1: is one of the more compelling theories of what happened. Yeah,

459
00:25:27,840 --> 00:25:29,959
Speaker 1: it's important to realize, as you say, that these are

460
00:25:30,000 --> 00:25:32,800
Speaker 1: not like dinosaurs seeking asteroids that didn't come and then

461
00:25:32,840 --> 00:25:35,600
Speaker 1: like hunt down all the dinosaurs and kill them one

462
00:25:35,640 --> 00:25:37,480
Speaker 1: by one. It really is a lot of the death

463
00:25:37,560 --> 00:25:40,600
Speaker 1: probably came from the change in the environment and all

464
00:25:40,600 --> 00:25:42,360
Speaker 1: this stuff is now up in the atmosphere and you're

465
00:25:42,359 --> 00:25:45,520
Speaker 1: blocking the sun's light and so, as you say, ecosystems

466
00:25:45,760 --> 00:25:48,240
Speaker 1: react to that, and now you have to survive in

467
00:25:48,240 --> 00:25:50,160
Speaker 1: a pretty new world. I don't know if anybody out

468
00:25:50,160 --> 00:25:53,720
Speaker 1: there it was a fan of the Dinosaurs sitcom aired

469
00:25:53,760 --> 00:25:56,040
Speaker 1: I think in the eighties and nineties, but the theories.

470
00:25:56,040 --> 00:25:59,840
Speaker 1: Finale of that episode actually features like basically an Aster

471
00:26:00,080 --> 00:26:03,360
Speaker 1: Royd winter where they're all hovering in their house as

472
00:26:03,400 --> 00:26:05,840
Speaker 1: the snow comes down and they're not expecting to see

473
00:26:05,840 --> 00:26:08,000
Speaker 1: the sun for years. It's sort of a bleak ending

474
00:26:08,119 --> 00:26:11,679
Speaker 1: to a comedy series. It was a huge bummer. I

475
00:26:11,720 --> 00:26:14,199
Speaker 1: think it was sort of a cautionary tale because it

476
00:26:14,280 --> 00:26:19,280
Speaker 1: was something about some dino corporation caused this to happen,

477
00:26:19,400 --> 00:26:22,280
Speaker 1: and so it was I think supposed to be an

478
00:26:22,359 --> 00:26:26,240
Speaker 1: environmental message about not destroying our own planet with global

479
00:26:26,280 --> 00:26:31,240
Speaker 1: warming or or whatever you know potential ramifications of destroying

480
00:26:31,240 --> 00:26:34,520
Speaker 1: our environment would be. And it wasn't a comedy. It

481
00:26:34,560 --> 00:26:38,560
Speaker 1: was like this lighthearted comedy with these big puppet dinosaurs

482
00:26:38,600 --> 00:26:41,440
Speaker 1: and like, you know, a dinosaur baby that would hit

483
00:26:41,640 --> 00:26:44,080
Speaker 1: the father with a frying pans. So it was as

484
00:26:44,119 --> 00:26:49,280
Speaker 1: if The Simpsons ended on basically a nuclear war and

485
00:26:49,359 --> 00:26:53,080
Speaker 1: everyone dies. How inappropriate to combine you know, hard hitting

486
00:26:53,080 --> 00:26:56,120
Speaker 1: science with ridiculous jokes. I mean, you choose that kind

487
00:26:56,160 --> 00:26:59,159
Speaker 1: of venue for talking about as a serious topic. Anyway,

488
00:26:59,280 --> 00:27:02,280
Speaker 1: let's keep making some jokes about how all the dinosaurs

489
00:27:02,440 --> 00:27:04,800
Speaker 1: were wiped out millions of years ago. But I think

490
00:27:04,840 --> 00:27:07,879
Speaker 1: it's important to understand where these things come from. Like,

491
00:27:08,160 --> 00:27:11,280
Speaker 1: these rocks don't just appear in space and get dropped

492
00:27:11,320 --> 00:27:13,640
Speaker 1: on the Earth. These are not like malevolent aliens. As

493
00:27:13,680 --> 00:27:17,199
Speaker 1: far as we know, these are parts of our Solar system.

494
00:27:17,280 --> 00:27:19,480
Speaker 1: When big misimpression is that these rocks might come from

495
00:27:19,480 --> 00:27:23,200
Speaker 1: really deep space, like from outside our Solar system to impact,

496
00:27:23,440 --> 00:27:26,919
Speaker 1: that's actually really quite rare because our star is pretty

497
00:27:26,920 --> 00:27:30,000
Speaker 1: far away from other stars. You know, there's many light

498
00:27:30,080 --> 00:27:32,640
Speaker 1: years between us and the next star, and many many

499
00:27:32,640 --> 00:27:35,399
Speaker 1: more between most stars. So there's only been a few

500
00:27:35,440 --> 00:27:38,520
Speaker 1: examples of times when we've even seen a rock come

501
00:27:38,720 --> 00:27:42,760
Speaker 1: from another Solar system and passed through hours like Omamua.

502
00:27:43,240 --> 00:27:45,880
Speaker 1: Most of the times when we're thinking about impacts on Earth,

503
00:27:46,040 --> 00:27:49,000
Speaker 1: we're talking about our own neighbors. We're talking about sources

504
00:27:49,040 --> 00:27:51,800
Speaker 1: in the Solar system. Isn't that the thing with like

505
00:27:51,960 --> 00:27:56,199
Speaker 1: murders and stuff, where stranger danger is pretty overly hyped

506
00:27:56,240 --> 00:27:58,919
Speaker 1: and it's usually someone you know that murders you. I

507
00:27:58,920 --> 00:28:02,160
Speaker 1: guess it's the same thing with asteroids. It's the asteroid

508
00:28:02,240 --> 00:28:05,040
Speaker 1: you know, your neighbor, that comes and destroys your planet.

509
00:28:05,160 --> 00:28:08,200
Speaker 1: Another good example of inappropriate humor, Katie wow Now we're

510
00:28:08,280 --> 00:28:10,720
Speaker 1: now we're joking about murders. I'm going to go to

511
00:28:10,760 --> 00:28:13,040
Speaker 1: podcast jail. No, But you're exactly right. And the thing

512
00:28:13,080 --> 00:28:16,840
Speaker 1: to understand is that the Solar System, like life on Earth,

513
00:28:16,960 --> 00:28:21,639
Speaker 1: has not stopped developing. It's a continuous, ongoing process. Solar

514
00:28:21,680 --> 00:28:23,760
Speaker 1: system is about four and a half billion years old,

515
00:28:23,800 --> 00:28:26,600
Speaker 1: and it's started from some huge cloud of gas and

516
00:28:26,720 --> 00:28:29,560
Speaker 1: dust and little bits of rock left over from the

517
00:28:29,640 --> 00:28:32,879
Speaker 1: death of other stars and coalesced into these planets and

518
00:28:32,920 --> 00:28:36,000
Speaker 1: all of these bits. But it's a dynamic, ongoing process.

519
00:28:36,040 --> 00:28:38,320
Speaker 1: And as we study our Solar system and compare it

520
00:28:38,400 --> 00:28:41,280
Speaker 1: to other solar systems, we understand that lots of things

521
00:28:41,360 --> 00:28:44,960
Speaker 1: are changing through that history of the Solar System. Planets

522
00:28:45,000 --> 00:28:47,960
Speaker 1: might even be changing position. We think that Jupiter amount

523
00:28:48,000 --> 00:28:50,120
Speaker 1: have formed in the outer part of the Solar System

524
00:28:50,320 --> 00:28:52,600
Speaker 1: and then taken a trip to the inner Solar System

525
00:28:52,640 --> 00:28:55,560
Speaker 1: before being pulled back out by Saturn into the outer

526
00:28:55,680 --> 00:28:58,400
Speaker 1: Solar System again. So don't think of the Solar system

527
00:28:58,480 --> 00:29:00,720
Speaker 1: is like a static place where it's finished and it's

528
00:29:00,720 --> 00:29:03,600
Speaker 1: going to be like this forever. It's still ongoing. And

529
00:29:03,640 --> 00:29:06,720
Speaker 1: that goes double for the little bits, not just the planets,

530
00:29:06,880 --> 00:29:09,760
Speaker 1: but the extra little rocks that didn't find their way

531
00:29:09,880 --> 00:29:12,160
Speaker 1: into a big planet. So we know, for example that

532
00:29:12,240 --> 00:29:15,960
Speaker 1: between Mars and Jupiter there's the asteroid belt. Right, These

533
00:29:16,000 --> 00:29:18,560
Speaker 1: are a bunch of little rocks that are not part

534
00:29:18,600 --> 00:29:21,440
Speaker 1: of any planet. And it's not just between Mars and Jupiter.

535
00:29:21,480 --> 00:29:24,440
Speaker 1: There are actually two blobs that are in Jupiter's orbit,

536
00:29:24,560 --> 00:29:27,080
Speaker 1: and like in the same ellipse where Jupiter goes around

537
00:29:27,080 --> 00:29:29,200
Speaker 1: the Sun is a blob that goes ahead of them

538
00:29:29,200 --> 00:29:31,680
Speaker 1: and a blob that goes behind them. That I think

539
00:29:31,840 --> 00:29:34,120
Speaker 1: is really cool. It shows you sort of why the

540
00:29:34,160 --> 00:29:38,760
Speaker 1: asteroids exist exist because of Jupiter's gravity. Jupiter's like this

541
00:29:38,880 --> 00:29:41,480
Speaker 1: huge bully in the outer Solar System. It wasn't for

542
00:29:41,560 --> 00:29:45,280
Speaker 1: Jupiter these rocks might coalesce into a planet. We did

543
00:29:45,280 --> 00:29:48,720
Speaker 1: an episode recently about like why planets get rings versus moons,

544
00:29:48,920 --> 00:29:51,400
Speaker 1: and the answer there was because of the tidal forces

545
00:29:51,440 --> 00:29:54,239
Speaker 1: of the planets, pulling those moons apart into rings if

546
00:29:54,240 --> 00:29:56,640
Speaker 1: they're too close. This is sort of a similar thing.

547
00:29:56,760 --> 00:29:59,600
Speaker 1: Jupiter is tugging on all of these guys, preventing them

548
00:29:59,600 --> 00:30:03,280
Speaker 1: from well lessen into a single larger thing. So you

549
00:30:03,320 --> 00:30:06,400
Speaker 1: have this huge collection of rocks. But again that's not static.

550
00:30:06,600 --> 00:30:08,360
Speaker 1: It used to be in the much earlier times in

551
00:30:08,400 --> 00:30:11,600
Speaker 1: the Solar System that the asteroid belt was much much richer,

552
00:30:11,640 --> 00:30:14,360
Speaker 1: There was much more mass. A lot of that has

553
00:30:14,400 --> 00:30:17,080
Speaker 1: gotten lost because it's a little bit unstable. Things fall

554
00:30:17,160 --> 00:30:19,280
Speaker 1: in towards the Sun or get knocked out of the

555
00:30:19,320 --> 00:30:22,560
Speaker 1: asteroid belt by collisions or just by Jupiter's gravity. What

556
00:30:22,800 --> 00:30:26,840
Speaker 1: causes something to get knocked out of stability? So you

557
00:30:26,880 --> 00:30:31,120
Speaker 1: have this asteroid built, what is the impetus for one

558
00:30:31,160 --> 00:30:34,160
Speaker 1: of these asteroids just deciding to go like, well, see

559
00:30:34,200 --> 00:30:36,520
Speaker 1: it and fall into the Sun. Think about it the

560
00:30:36,520 --> 00:30:38,120
Speaker 1: other direction. What do you have to do in order

561
00:30:38,120 --> 00:30:42,440
Speaker 1: to survive over billions of years? You have Jupiter's gravity

562
00:30:42,480 --> 00:30:45,480
Speaker 1: tugging at you, if all the other planets also tugging

563
00:30:45,520 --> 00:30:47,440
Speaker 1: at you even less, and of course the Sun. In

564
00:30:47,560 --> 00:30:50,040
Speaker 1: order to survive you have to somehow balance all of

565
00:30:50,080 --> 00:30:52,800
Speaker 1: those things for billions of years. So you start out

566
00:30:52,840 --> 00:30:55,120
Speaker 1: with a huge number of rocks, and nobody has organized

567
00:30:55,160 --> 00:30:56,680
Speaker 1: these right there, just sort of like out there in

568
00:30:56,720 --> 00:31:00,479
Speaker 1: the Solar System. They formed gravitationally, and most of them

569
00:31:00,480 --> 00:31:02,959
Speaker 1: are just not on trajectories that are going to survive.

570
00:31:02,960 --> 00:31:05,320
Speaker 1: They're gonna get tugged by Jupiter, or they're gonna get

571
00:31:05,400 --> 00:31:08,160
Speaker 1: yanked by Mars, or they're gonna feel Saturn's pull, and

572
00:31:08,160 --> 00:31:10,560
Speaker 1: then eventually they're gonna fall into the Sun or into

573
00:31:10,600 --> 00:31:14,200
Speaker 1: another planet. So it requires like a really delicate balance

574
00:31:14,240 --> 00:31:17,240
Speaker 1: of all of those gravitational factors in order to survive

575
00:31:17,360 --> 00:31:20,120
Speaker 1: this long, and as time goes on, you're less and

576
00:31:20,200 --> 00:31:22,760
Speaker 1: less likely to survive because you know, it's really chaotic.

577
00:31:22,840 --> 00:31:26,000
Speaker 1: Like you can orbit a single object pretty stable for

578
00:31:26,040 --> 00:31:28,840
Speaker 1: a long long time, you're just feeling gravity towards it.

579
00:31:28,920 --> 00:31:31,160
Speaker 1: You have the right angle you can orbit. Now you

580
00:31:31,160 --> 00:31:33,800
Speaker 1: add another object in the Solar System, another thing with

581
00:31:33,840 --> 00:31:37,880
Speaker 1: heavy gravity, becomes much more complicated to keep a stable orbit.

582
00:31:38,320 --> 00:31:41,280
Speaker 1: Like the Earth, for example, its orbit is constantly being

583
00:31:41,320 --> 00:31:44,760
Speaker 1: tweaked by Jupiter and by Saturn, these tiny little tugs,

584
00:31:44,880 --> 00:31:46,840
Speaker 1: and so it's hard to find a path which is

585
00:31:46,840 --> 00:31:50,080
Speaker 1: going to be stable over billions of years. It's amazing, frankly,

586
00:31:50,120 --> 00:31:52,800
Speaker 1: that any of these asteroids were able to survive this

587
00:31:52,960 --> 00:31:56,920
Speaker 1: fairly chaotic gravitational system that long. I mean that kind

588
00:31:56,920 --> 00:32:00,240
Speaker 1: of sounds similar to evolution, where you know, the rule

589
00:32:00,320 --> 00:32:03,360
Speaker 1: is simple. If you survive, you survive, and if you don't,

590
00:32:03,480 --> 00:32:06,680
Speaker 1: you get tossed into the Sun or pulled into the Sun. Yeah.

591
00:32:06,800 --> 00:32:09,920
Speaker 1: The difference here is that there's no way to reproduce, right,

592
00:32:09,960 --> 00:32:12,680
Speaker 1: there's no like way to replenish these meteors that we

593
00:32:12,760 --> 00:32:17,719
Speaker 1: know that we know of exactly unless like two planets

594
00:32:17,800 --> 00:32:20,360
Speaker 1: collide and create a lot of debris. But our model

595
00:32:20,400 --> 00:32:23,680
Speaker 1: of the asteroid belt is that it's like point one

596
00:32:23,840 --> 00:32:27,600
Speaker 1: percent of its original mass. The first hundred million years

597
00:32:27,600 --> 00:32:30,920
Speaker 1: of the Solar System were pretty chaotic collisions all the time,

598
00:32:30,960 --> 00:32:32,920
Speaker 1: and things were falling out of it. So the asteroid

599
00:32:32,920 --> 00:32:36,000
Speaker 1: belt we think now is much much less mass than

600
00:32:36,040 --> 00:32:37,880
Speaker 1: it used to be. In total, if you took like

601
00:32:38,040 --> 00:32:40,440
Speaker 1: all the asteroids and the asteroid belt and add them up,

602
00:32:40,480 --> 00:32:42,920
Speaker 1: it'd be less than five percent of the mass of

603
00:32:42,960 --> 00:32:47,120
Speaker 1: our moon. So there's not actually that much stuff out there.

604
00:32:47,520 --> 00:32:50,240
Speaker 1: Is That good news for us? Because the more stuff,

605
00:32:50,240 --> 00:32:52,160
Speaker 1: it seems like, the more likely we're going to get

606
00:32:52,240 --> 00:32:54,600
Speaker 1: hit by that stuff. That's very good news for us.

607
00:32:54,680 --> 00:32:57,840
Speaker 1: We want fewer asteroids because each one is like a bullet, right,

608
00:32:58,080 --> 00:33:00,640
Speaker 1: Any of these things, if they're bigger and like ten

609
00:33:00,720 --> 00:33:03,959
Speaker 1: kilometers or so and they hit the Earth, that's an

610
00:33:03,960 --> 00:33:07,960
Speaker 1: extinction event, right, that's really catastrophic. Some of these guys

611
00:33:07,960 --> 00:33:11,000
Speaker 1: are huge. Like there's a dwarf planet in the asteroid belt,

612
00:33:11,080 --> 00:33:15,760
Speaker 1: it's called Series, and it's nine fifty kilometers in diameter, right,

613
00:33:15,800 --> 00:33:18,400
Speaker 1: that would just obliterate the surface of the Earth completely.

614
00:33:18,600 --> 00:33:23,080
Speaker 1: That sounds pretty serious. So it seems like earlier on,

615
00:33:23,200 --> 00:33:26,480
Speaker 1: like we probably had more asteroid collisions near Earth, because

616
00:33:26,520 --> 00:33:29,880
Speaker 1: like the Moon has a bunch of craters, But has

617
00:33:29,920 --> 00:33:33,760
Speaker 1: the Moon been hit by asteroids more recently? Was that

618
00:33:33,800 --> 00:33:36,720
Speaker 1: like debris from Earth hitting the Moon? Why do we

619
00:33:36,880 --> 00:33:41,200
Speaker 1: have more craters Like that seemed to be old than

620
00:33:41,640 --> 00:33:45,000
Speaker 1: we are currently experiencing in terms of getting hit by

621
00:33:45,120 --> 00:33:47,640
Speaker 1: space rocks. Yeah, there's a few things going on there.

622
00:33:47,720 --> 00:33:50,160
Speaker 1: It's true that we have fewer space rocks hitting things

623
00:33:50,240 --> 00:33:52,640
Speaker 1: now than we used to in the very early days

624
00:33:52,680 --> 00:33:55,080
Speaker 1: of the Solar System, just because there are fewer and

625
00:33:55,120 --> 00:33:57,640
Speaker 1: we sort of run out and the trend is towards

626
00:33:58,040 --> 00:34:01,720
Speaker 1: things coalescing into larger objects. So we just have fewer

627
00:34:01,720 --> 00:34:04,120
Speaker 1: of these rocks, which means fewer impacts. But there still

628
00:34:04,160 --> 00:34:06,239
Speaker 1: are a lot of impacts. And if you look at

629
00:34:06,240 --> 00:34:08,760
Speaker 1: the Moon, there's a very rich history there of impacts

630
00:34:08,760 --> 00:34:11,520
Speaker 1: and you can see, for example, really big craters that

631
00:34:11,600 --> 00:34:14,879
Speaker 1: you can tell are old with smaller craters inside them,

632
00:34:14,920 --> 00:34:17,520
Speaker 1: and so you can use that to tell like which

633
00:34:17,560 --> 00:34:21,120
Speaker 1: ones happened first because of the small crater it happened first,

634
00:34:21,280 --> 00:34:23,759
Speaker 1: the big one would have obliterated it. So you can

635
00:34:23,800 --> 00:34:26,759
Speaker 1: tell the sort of like the layers of cratering there,

636
00:34:27,160 --> 00:34:29,120
Speaker 1: and you can use that to try to reconstruct something

637
00:34:29,120 --> 00:34:32,239
Speaker 1: about the history of cratering on the Moon. But yeah,

638
00:34:32,280 --> 00:34:35,120
Speaker 1: there was definitely more cratering earlier on. And remember that

639
00:34:35,160 --> 00:34:38,080
Speaker 1: the Moon doesn't really have much of an atmosphere, has

640
00:34:38,160 --> 00:34:41,520
Speaker 1: almost no atmosphere. We just did an episode about the

641
00:34:41,520 --> 00:34:45,000
Speaker 1: Moon's atmosphere. It's like a few molecules per cubic centimeter,

642
00:34:45,120 --> 00:34:47,719
Speaker 1: whereas the Earth is like ten to the nineteen the

643
00:34:47,800 --> 00:34:51,520
Speaker 1: molecules per cubic centimeter, and that's a huge shield. Any

644
00:34:51,640 --> 00:34:54,040
Speaker 1: rock that hits the Moon is going to cause a crater,

645
00:34:54,280 --> 00:34:56,400
Speaker 1: whereas the rock that hits the Earth, if it's not

646
00:34:56,480 --> 00:34:59,400
Speaker 1: big enough, is going to burn up in our atmosphere

647
00:34:59,440 --> 00:35:02,240
Speaker 1: and we're not going to see it. So every surface

648
00:35:02,280 --> 00:35:05,240
Speaker 1: of the Solar System is constantly getting bombarded by smaller

649
00:35:05,320 --> 00:35:08,960
Speaker 1: rocks and sometimes bigger ones Earth. We don't often notice

650
00:35:09,000 --> 00:35:11,960
Speaker 1: that because our atmosphere protects us, but a big enough

651
00:35:12,040 --> 00:35:14,000
Speaker 1: one is definitely going to make it to the surface

652
00:35:14,000 --> 00:35:16,200
Speaker 1: of the Earth and do some damage. Well, I want

653
00:35:16,200 --> 00:35:20,120
Speaker 1: to hear about how we can predict whether one of

654
00:35:20,120 --> 00:35:22,719
Speaker 1: these big ones are gonna hit us, But I think

655
00:35:22,840 --> 00:35:25,239
Speaker 1: first I'm going to take a quick break to hide

656
00:35:25,320 --> 00:35:40,960
Speaker 1: under the bed a little bit. So we've talked about

657
00:35:41,040 --> 00:35:45,080
Speaker 1: how there is a lot of asteroid activity, that there's

658
00:35:45,080 --> 00:35:49,480
Speaker 1: a lot of randomness and chaos to the movement of asteroids,

659
00:35:49,520 --> 00:35:53,000
Speaker 1: like from say like the asteroid belt to falling into

660
00:35:53,000 --> 00:35:56,919
Speaker 1: the Sun. So it seems like there's so much randomness

661
00:35:57,000 --> 00:35:59,759
Speaker 1: it would be like really hard to predict if one

662
00:35:59,800 --> 00:36:01,799
Speaker 1: of the these guys would come and hit us. It

663
00:36:01,840 --> 00:36:04,960
Speaker 1: does seem like a lot of the process is random, right,

664
00:36:05,080 --> 00:36:07,759
Speaker 1: Like what makes an asteroid hit the Earth or not

665
00:36:07,920 --> 00:36:10,160
Speaker 1: hit the Earth. It does seem like it just needs

666
00:36:10,160 --> 00:36:12,319
Speaker 1: to get tugged the right way gravitationally and then end

667
00:36:12,400 --> 00:36:13,880
Speaker 1: up on a path. You know, for those of you

668
00:36:13,920 --> 00:36:17,040
Speaker 1: out there who are more anxious, NASA is doing their best.

669
00:36:17,080 --> 00:36:19,600
Speaker 1: They have a bunch of telescopes now tracking these things,

670
00:36:19,680 --> 00:36:21,720
Speaker 1: and they think they know where all of the big

671
00:36:21,760 --> 00:36:24,319
Speaker 1: asteroids are, the ones that might do any damage to

672
00:36:24,360 --> 00:36:26,480
Speaker 1: the Earth. They can't find all the asteroids because they

673
00:36:26,520 --> 00:36:28,360
Speaker 1: get to be pretty small, but the bigger ones, and

674
00:36:28,480 --> 00:36:31,640
Speaker 1: especially the shinier ones, they've had a lot of opportunities

675
00:36:31,680 --> 00:36:33,879
Speaker 1: to see these things because the asteroid belt is pretty close,

676
00:36:33,920 --> 00:36:35,920
Speaker 1: so we get lots of chances. The things that are

677
00:36:35,960 --> 00:36:38,360
Speaker 1: harder to predict are the things that come from further

678
00:36:38,480 --> 00:36:41,280
Speaker 1: out in our own solar system. These seem a little

679
00:36:41,280 --> 00:36:44,319
Speaker 1: bit more random and harder to anticipate because they're on

680
00:36:44,400 --> 00:36:47,480
Speaker 1: longer time scales, and those are things like comets. So

681
00:36:47,600 --> 00:36:50,720
Speaker 1: out past the asteroid belt, that's something called the Kuiper

682
00:36:50,840 --> 00:36:53,880
Speaker 1: Belt is now past Neptune. It's like thirty a U

683
00:36:54,080 --> 00:36:56,640
Speaker 1: out there, and instead of just being rock, these things

684
00:36:56,680 --> 00:36:59,839
Speaker 1: are icy rocks out past the snow line, and so

685
00:37:00,239 --> 00:37:04,120
Speaker 1: it's cold enough for vapor to coalesce into ice. These

686
00:37:04,160 --> 00:37:07,160
Speaker 1: chunky ice balls can also get disrupted and then fall

687
00:37:07,239 --> 00:37:10,080
Speaker 1: towards the inner Solar system, and that's what we typically

688
00:37:10,120 --> 00:37:12,680
Speaker 1: call a comet to have a tail, because this ice

689
00:37:12,800 --> 00:37:15,400
Speaker 1: is getting boiled off as they get closer and closer

690
00:37:15,440 --> 00:37:17,919
Speaker 1: to the Sun, and the Kuiper Belt is responsible for

691
00:37:18,120 --> 00:37:21,400
Speaker 1: what we call short period commets, ones that loop around

692
00:37:21,400 --> 00:37:24,520
Speaker 1: every two hundred years or so. That doesn't seem very short, right.

693
00:37:24,560 --> 00:37:26,600
Speaker 1: The problem though, is that if it only comes every

694
00:37:26,600 --> 00:37:30,080
Speaker 1: two hundred years, and we've only had like telescope technology

695
00:37:30,120 --> 00:37:32,120
Speaker 1: for a few hundred years, and we don't get very

696
00:37:32,120 --> 00:37:35,440
Speaker 1: many chances to see these things and like understand their

697
00:37:35,560 --> 00:37:38,719
Speaker 1: orbit and predict very well whether they're going to hit

698
00:37:38,760 --> 00:37:41,600
Speaker 1: the Earth. How much lead time would we have, like

699
00:37:41,680 --> 00:37:45,879
Speaker 1: from first spotting a comment to it making contact with Earth,

700
00:37:46,040 --> 00:37:49,600
Speaker 1: Like how fast could it move from when we could

701
00:37:49,640 --> 00:37:53,080
Speaker 1: first feasibly see it too when it would hit us.

702
00:37:53,440 --> 00:37:55,319
Speaker 1: It's a great question, and we have an answer to

703
00:37:55,360 --> 00:37:58,279
Speaker 1: that because it's happened right Commas Shoemaker levee, which hit

704
00:37:58,360 --> 00:38:00,960
Speaker 1: Jupiter in the nineties. We knew that was going to

705
00:38:01,080 --> 00:38:04,080
Speaker 1: hit but only a few months in advance because it

706
00:38:04,120 --> 00:38:06,439
Speaker 1: comes from pretty far out in the Solar system where

707
00:38:06,440 --> 00:38:08,960
Speaker 1: it's hard to track, and then as it comes in

708
00:38:09,040 --> 00:38:11,480
Speaker 1: people can calculate its trajectory and see where it's going

709
00:38:11,520 --> 00:38:14,000
Speaker 1: to loop around this time, and that's how we knew

710
00:38:14,040 --> 00:38:16,239
Speaker 1: it was going to hit Jupiter. And so some of

711
00:38:16,280 --> 00:38:19,000
Speaker 1: these things can come sort of out of the darkness

712
00:38:19,160 --> 00:38:21,680
Speaker 1: and surprise us. The scary thing is that there are

713
00:38:21,719 --> 00:38:25,320
Speaker 1: also long period comets, these things from the ord cloud,

714
00:38:25,719 --> 00:38:28,359
Speaker 1: and there might be like trillions of things out there,

715
00:38:28,480 --> 00:38:32,440
Speaker 1: much much further out, very loosely held by the Sun's gravity,

716
00:38:32,520 --> 00:38:35,160
Speaker 1: and these things can give comments that have really long

717
00:38:35,239 --> 00:38:38,760
Speaker 1: periods five hundred years, a thousand years, maybe even longer,

718
00:38:39,160 --> 00:38:42,640
Speaker 1: you know, looping through our solar system once every million years.

719
00:38:42,800 --> 00:38:46,040
Speaker 1: And so this is another source of potential killers. And

720
00:38:46,080 --> 00:38:48,800
Speaker 1: one issue is that because they come from so far out,

721
00:38:49,200 --> 00:38:52,080
Speaker 1: when they come in, they're gonna be moving very very fast,

722
00:38:52,440 --> 00:38:56,279
Speaker 1: which makes them hard to predict and also very very dangerous.

723
00:38:56,680 --> 00:39:00,480
Speaker 1: So comets are harder to predict than asteroids and also

724
00:39:00,680 --> 00:39:03,880
Speaker 1: faster moving, so they're really something to be more worried

725
00:39:03,880 --> 00:39:07,080
Speaker 1: about than asteroids. Well I hate that, so thank you

726
00:39:07,120 --> 00:39:12,279
Speaker 1: for that, so ignoring that kind of mortal peril. Are

727
00:39:12,280 --> 00:39:16,720
Speaker 1: we able to predict asteroids better than we can predict

728
00:39:16,760 --> 00:39:22,320
Speaker 1: comments like ore? Is there some science to understanding when

729
00:39:22,480 --> 00:39:25,239
Speaker 1: asteroids would hit us? There is some science there, but

730
00:39:25,320 --> 00:39:27,719
Speaker 1: we're not great at predicting asteroids more than like a

731
00:39:27,760 --> 00:39:30,640
Speaker 1: couple hundred years out. The more measurements you have of

732
00:39:30,680 --> 00:39:33,440
Speaker 1: an object, the better you can predict its trajectory. If

733
00:39:33,440 --> 00:39:36,400
Speaker 1: you've seen an asteroid a hundred times or a thousand times,

734
00:39:36,520 --> 00:39:38,840
Speaker 1: then you have a good sense of exactly what direction

735
00:39:38,840 --> 00:39:41,680
Speaker 1: it's going in and what its velocity is, and you

736
00:39:41,719 --> 00:39:44,319
Speaker 1: can predict pretty well where it's going to go. In

737
00:39:44,320 --> 00:39:46,839
Speaker 1: the end, it always becomes chaotic because there's so many

738
00:39:46,880 --> 00:39:49,600
Speaker 1: things in the Solar System that can tug on it.

739
00:39:49,520 --> 00:39:52,239
Speaker 1: It makes it hard to predict. Comments are harder if

740
00:39:52,280 --> 00:39:54,560
Speaker 1: you don't have much data, if you've only seen it once,

741
00:39:54,640 --> 00:39:56,759
Speaker 1: or if you've never seen it before, where it's just

742
00:39:57,000 --> 00:39:59,080
Speaker 1: entering the Solar system, and you know, the things that

743
00:39:59,120 --> 00:40:02,359
Speaker 1: trigger asteroid or comets to fall into the Earth are

744
00:40:02,480 --> 00:40:07,279
Speaker 1: these gravitational tugs. Right the Solar system, like left to itself,

745
00:40:07,600 --> 00:40:11,600
Speaker 1: is pretty stable. There's some gravitational chaos internally, but something

746
00:40:11,640 --> 00:40:13,759
Speaker 1: that we need to think about our effects from other

747
00:40:13,960 --> 00:40:17,000
Speaker 1: Solar systems. You know, the Sun is moving through the

748
00:40:17,040 --> 00:40:20,120
Speaker 1: galaxy and right now it's pretty far from other stars,

749
00:40:20,200 --> 00:40:22,719
Speaker 1: but as time goes on, it gets closer to other

750
00:40:22,719 --> 00:40:24,960
Speaker 1: stars and further from other stars. It's sort of like

751
00:40:25,280 --> 00:40:28,960
Speaker 1: swimming through an ocean of the galaxy. And if you

752
00:40:29,000 --> 00:40:31,200
Speaker 1: have these things out there in the or cloud that

753
00:40:31,239 --> 00:40:34,000
Speaker 1: are sort of like very tenuously held by the Sun.

754
00:40:34,320 --> 00:40:36,719
Speaker 1: Then a little tug from something else out there might

755
00:40:36,800 --> 00:40:38,759
Speaker 1: not get out of the stable orbit it's been in

756
00:40:38,840 --> 00:40:42,160
Speaker 1: for billions of years and send it rocketing towards the

757
00:40:42,160 --> 00:40:46,680
Speaker 1: inner Solar System. We do have ways to predict things

758
00:40:46,719 --> 00:40:51,480
Speaker 1: that's not always completely accurate, but it's based on like probabilities.

759
00:40:51,480 --> 00:40:54,560
Speaker 1: So like if you have a coin and you're flipping it,

760
00:40:54,680 --> 00:40:58,560
Speaker 1: you can't really with complete accuracy predict whether it's going

761
00:40:58,600 --> 00:41:01,480
Speaker 1: to be heads or tails, but you have an idea

762
00:41:01,640 --> 00:41:04,040
Speaker 1: of if you flip it a bunch of times that

763
00:41:04,239 --> 00:41:07,160
Speaker 1: you know roughly fifty percent at the time it should

764
00:41:07,200 --> 00:41:09,680
Speaker 1: be heads and fifty percent of the time it should

765
00:41:09,719 --> 00:41:12,239
Speaker 1: be tails. So do we have a similar thing when

766
00:41:12,280 --> 00:41:15,960
Speaker 1: it comes to asteroids, Like maybe we can't precisely predict

767
00:41:16,040 --> 00:41:19,240
Speaker 1: when an asteroid would hit us, but we have an

768
00:41:19,280 --> 00:41:23,439
Speaker 1: idea of the rough probability of asteroid hitting us over

769
00:41:23,640 --> 00:41:26,600
Speaker 1: the history of our planet. We can look back into

770
00:41:26,680 --> 00:41:29,239
Speaker 1: our history and try to see if there are patterns

771
00:41:29,280 --> 00:41:31,800
Speaker 1: there to see if there is a periodicity. But before

772
00:41:31,800 --> 00:41:33,440
Speaker 1: we do that, it's fun to think about, like what

773
00:41:33,600 --> 00:41:36,960
Speaker 1: might be causing that periodicity, Like are there even conceivably

774
00:41:37,080 --> 00:41:41,440
Speaker 1: theories that might generate that kind of pattern, because a

775
00:41:41,480 --> 00:41:44,480
Speaker 1: pattern means that there's something underlying happening. There's some like

776
00:41:44,760 --> 00:41:48,440
Speaker 1: very slow process which is grinding forward, which is changing

777
00:41:48,480 --> 00:41:52,080
Speaker 1: the nature of the environment in a way that's predictable. Right.

778
00:41:52,120 --> 00:41:55,480
Speaker 1: That's periodic, the way like the seasons are periodic. Because

779
00:41:55,520 --> 00:41:57,760
Speaker 1: of the way the Earth goes around the Sun, people

780
00:41:57,760 --> 00:42:00,560
Speaker 1: have looked for these kinds of things in our galaxy,

781
00:42:00,680 --> 00:42:03,920
Speaker 1: like periodic events that happen over tens of millions of

782
00:42:04,000 --> 00:42:07,560
Speaker 1: years that might trigger asteroids and comments to hit the

783
00:42:07,560 --> 00:42:09,440
Speaker 1: Earth on some sort of time scale. And there's a

784
00:42:09,480 --> 00:42:12,239
Speaker 1: couple of candidates. One is sort of plausible and the

785
00:42:12,280 --> 00:42:14,920
Speaker 1: other one is kind of crazy and dramatic. The one

786
00:42:14,960 --> 00:42:17,719
Speaker 1: that's sort of plausible is that the Sun does have

787
00:42:17,920 --> 00:42:21,840
Speaker 1: a sort of thirty million year cycle in the galaxy.

788
00:42:22,000 --> 00:42:24,080
Speaker 1: So the Sun is going around the center of the galaxy,

789
00:42:24,080 --> 00:42:26,360
Speaker 1: and it takes a couple of hundred million years to

790
00:42:26,480 --> 00:42:29,279
Speaker 1: orbit the center of the galaxy. That's like one galactic year.

791
00:42:29,520 --> 00:42:32,120
Speaker 1: But the Sun is also wiggling sort of up and

792
00:42:32,320 --> 00:42:35,480
Speaker 1: down through the galactic plane. So if you imagine the

793
00:42:35,560 --> 00:42:37,640
Speaker 1: Sun like going around the center of the galaxy, it's

794
00:42:37,680 --> 00:42:41,280
Speaker 1: also going up and down above and below the galactic

795
00:42:41,320 --> 00:42:44,240
Speaker 1: plane as it does that, and that happens about every

796
00:42:44,360 --> 00:42:48,480
Speaker 1: thirty million years. We pass through the sort of plane

797
00:42:48,520 --> 00:42:50,720
Speaker 1: at the center of the galaxy and then go below

798
00:42:50,760 --> 00:42:53,719
Speaker 1: it and then come back up thirty million years later. So,

799
00:42:53,880 --> 00:42:57,239
Speaker 1: like I've always kind of thought of the Sun as

800
00:42:57,320 --> 00:43:01,440
Speaker 1: this pretty stable, massive or but now I'm thinking of

801
00:43:01,480 --> 00:43:04,840
Speaker 1: it like this rubber ducky that is like circling the

802
00:43:04,920 --> 00:43:08,320
Speaker 1: drain of the bathtub, kind of bobbing under the water

803
00:43:08,440 --> 00:43:11,279
Speaker 1: and over the water exactly. And as it moves through

804
00:43:11,320 --> 00:43:14,719
Speaker 1: the galaxy, its environment changes, we get further and closer

805
00:43:14,760 --> 00:43:17,640
Speaker 1: to other stars. The center of the galaxy. The galactic

806
00:43:17,680 --> 00:43:20,799
Speaker 1: plane is definitely the densest part of the galaxy. And

807
00:43:20,880 --> 00:43:23,800
Speaker 1: so it's not inconceivable that that kind of process my

808
00:43:23,920 --> 00:43:27,280
Speaker 1: trigger comets or Kuiper Belt objects out of their otherwise

809
00:43:27,280 --> 00:43:29,920
Speaker 1: stable orbit give it just the right kind of tug

810
00:43:30,200 --> 00:43:32,920
Speaker 1: that might cause them to fall towards the center of

811
00:43:32,960 --> 00:43:36,200
Speaker 1: the Solar system. So that's the more plausible theory. Then

812
00:43:36,200 --> 00:43:38,279
Speaker 1: there's a theory that was spread in a popular book

813
00:43:38,320 --> 00:43:42,200
Speaker 1: recently about whether dark matter killed the dinosaurs. This is

814
00:43:42,200 --> 00:43:44,840
Speaker 1: a book written by a couple of theorists at Harvard,

815
00:43:45,160 --> 00:43:48,440
Speaker 1: and they suggest that dark matter, which is this invisible

816
00:43:48,480 --> 00:43:50,600
Speaker 1: matter that we know is out there but we don't

817
00:43:50,640 --> 00:43:53,319
Speaker 1: really understand very much. That we know that there's much

818
00:43:53,360 --> 00:43:56,120
Speaker 1: more of it than there is normal matter, and we

819
00:43:56,200 --> 00:43:58,239
Speaker 1: think that it's shaped sort of the whole structure of

820
00:43:58,239 --> 00:44:01,719
Speaker 1: the galaxy. They imagine that dark matter might coalesced into

821
00:44:01,760 --> 00:44:05,439
Speaker 1: sort of like a disk, like a dark frisbee. Yeah,

822
00:44:05,960 --> 00:44:08,560
Speaker 1: like a big dark frisbee. And when the Sun passes

823
00:44:08,600 --> 00:44:10,920
Speaker 1: through this dark matter disc that maybe it's the dark

824
00:44:10,960 --> 00:44:13,720
Speaker 1: matter that's tugging on the things in the outer Solar

825
00:44:13,760 --> 00:44:17,360
Speaker 1: System and then knocking them in towards our safe little garden.

826
00:44:17,640 --> 00:44:20,520
Speaker 1: Is there any evidence for this? So is there any

827
00:44:20,560 --> 00:44:22,719
Speaker 1: evidence for this? You know, this is just a fun

828
00:44:22,840 --> 00:44:26,160
Speaker 1: speculative theory. These two Harvard theorists came up with a

829
00:44:26,239 --> 00:44:28,640
Speaker 1: theory of dark matter that would generate this kind of

830
00:44:28,680 --> 00:44:30,560
Speaker 1: disc and then they went hunting to see if there

831
00:44:30,600 --> 00:44:33,799
Speaker 1: was evidence in the history on our planet for some

832
00:44:33,840 --> 00:44:36,440
Speaker 1: sort of periodicity, so that would be like an explanation

833
00:44:36,480 --> 00:44:39,279
Speaker 1: for that. We don't have any direct evidence of the

834
00:44:39,400 --> 00:44:43,360
Speaker 1: dark matter frisbee existing at all. It's just like another

835
00:44:43,480 --> 00:44:47,239
Speaker 1: idea that might generate a sort of periodic tug on

836
00:44:47,280 --> 00:44:50,000
Speaker 1: the Solar system that would create it. If indeed there

837
00:44:50,120 --> 00:44:53,759
Speaker 1: is any periodicity in the asteroid impacts on Earth, it

838
00:44:53,800 --> 00:44:57,000
Speaker 1: sounds like a very convenient scapegoat to me, Like if I,

839
00:44:57,800 --> 00:45:00,640
Speaker 1: you know, knock over a vase, I'm like, well, hey,

840
00:45:00,680 --> 00:45:04,200
Speaker 1: it's that dark matter, frisbee. You know how it is exactly.

841
00:45:04,400 --> 00:45:06,120
Speaker 1: And so now I think it's time to answer your

842
00:45:06,160 --> 00:45:08,480
Speaker 1: question from a few minutes ago, which is is there

843
00:45:08,520 --> 00:45:11,360
Speaker 1: actually any evidence can we look back on the history

844
00:45:11,400 --> 00:45:15,080
Speaker 1: on Earth and see a pattern of strikes, because you know,

845
00:45:15,160 --> 00:45:16,960
Speaker 1: one good way to predict the feature is of course

846
00:45:17,040 --> 00:45:19,279
Speaker 1: to look at the past and to see if this

847
00:45:19,320 --> 00:45:22,239
Speaker 1: has happened at regular intervals in the past. And this

848
00:45:22,320 --> 00:45:24,680
Speaker 1: is challenging, right because people weren't around, we've not been

849
00:45:24,680 --> 00:45:27,480
Speaker 1: doing astronomy for like hundreds of millions of years to

850
00:45:27,520 --> 00:45:29,640
Speaker 1: take this kind of data. But the sort of two

851
00:45:29,680 --> 00:45:32,319
Speaker 1: categories of evidence that people have looked at to see

852
00:45:32,360 --> 00:45:35,279
Speaker 1: if there are patterns. One is biological and the other

853
00:45:35,400 --> 00:45:38,800
Speaker 1: is geological. So first people look at like the history

854
00:45:38,800 --> 00:45:40,560
Speaker 1: of life on Earth, and they look at the fossil

855
00:45:40,640 --> 00:45:44,160
Speaker 1: record for extinctions, and there are a lot of them.

856
00:45:44,360 --> 00:45:46,080
Speaker 1: You know, if you look back in the history of

857
00:45:46,160 --> 00:45:49,240
Speaker 1: life on Earth is many times when you've had massive

858
00:45:49,280 --> 00:45:53,239
Speaker 1: dieots and big decreases in the diversity of life on Earth. Yeah, yeah,

859
00:45:53,320 --> 00:45:57,200
Speaker 1: you have these like bottleneck events you can look at,

860
00:45:57,680 --> 00:46:00,640
Speaker 1: you know, these kind of genetic because it's like not

861
00:46:00,719 --> 00:46:03,520
Speaker 1: just in terms of you know, you'll have a massive

862
00:46:03,640 --> 00:46:06,759
Speaker 1: dump of fossils that you can look at and that

863
00:46:06,880 --> 00:46:08,880
Speaker 1: are kind of layered and so you can see like

864
00:46:09,040 --> 00:46:13,520
Speaker 1: where you get these uh, these basically evidence of all

865
00:46:13,560 --> 00:46:17,560
Speaker 1: these animals dying. You have interesting sort of genetic bottleneck

866
00:46:17,600 --> 00:46:20,600
Speaker 1: where you can see evidence of mass die offs. I

867
00:46:20,640 --> 00:46:24,480
Speaker 1: think we have this sort of nice notion that these

868
00:46:24,520 --> 00:46:28,960
Speaker 1: mass extinctions don't really happen because we have not really

869
00:46:29,280 --> 00:46:33,160
Speaker 1: been direct witnesses to a mass extinction and our human

870
00:46:33,640 --> 00:46:37,040
Speaker 1: species lifespan. But yeah, they do happen with you know,

871
00:46:37,400 --> 00:46:42,239
Speaker 1: some regularity, not too often, but it's something that it's

872
00:46:42,280 --> 00:46:45,400
Speaker 1: hard to think of happening to us because you know,

873
00:46:45,480 --> 00:46:48,440
Speaker 1: we like very much being alive on the planet. But yes,

874
00:46:48,480 --> 00:46:52,000
Speaker 1: it does happen exactly, and sometimes these processes only happen

875
00:46:52,160 --> 00:46:54,560
Speaker 1: in deep time or there's not things that we witness

876
00:46:54,680 --> 00:46:56,919
Speaker 1: day to day or year to year, but they still

877
00:46:57,000 --> 00:46:59,840
Speaker 1: are part of the larger cycle of life on Earth.

878
00:47:00,000 --> 00:47:02,120
Speaker 1: You just might not have been paying attention long enough

879
00:47:02,160 --> 00:47:05,080
Speaker 1: to notice. And so you know, sixty five million years

880
00:47:05,120 --> 00:47:07,920
Speaker 1: ago there was a big die off, like to the species.

881
00:47:07,960 --> 00:47:11,800
Speaker 1: Two fifty million years ago there was a huge die off.

882
00:47:11,960 --> 00:47:14,920
Speaker 1: And the boundary between the Permian and Triassic period that

883
00:47:14,960 --> 00:47:17,640
Speaker 1: I think people still don't even really understand, something like

884
00:47:17,800 --> 00:47:21,640
Speaker 1: fifty percent of species on Earth died out. And if

885
00:47:21,640 --> 00:47:24,920
Speaker 1: you look at like over time when have species died out?

886
00:47:24,920 --> 00:47:27,160
Speaker 1: And you do see these spikes and you wonder like

887
00:47:27,880 --> 00:47:30,160
Speaker 1: is there a pattern there? So people have done a

888
00:47:30,160 --> 00:47:32,680
Speaker 1: statistical analysis to see like can you fit this to

889
00:47:32,680 --> 00:47:35,760
Speaker 1: a periodic function? Is there like a gap between these

890
00:47:35,800 --> 00:47:39,000
Speaker 1: peaks that's pretty regular or not. The way to do

891
00:47:39,040 --> 00:47:42,560
Speaker 1: this mathematically is something called a Furrier analysis. For those

892
00:47:42,640 --> 00:47:46,359
Speaker 1: you like signal processing nerds out there, it's basically like

893
00:47:46,440 --> 00:47:49,960
Speaker 1: taking a sound and decomposing it into frequencies. You listen

894
00:47:50,000 --> 00:47:52,080
Speaker 1: to Bob Dylan, for example, and you can lower the base,

895
00:47:52,160 --> 00:47:54,160
Speaker 1: or you can raise the trouble, or you know, you

896
00:47:54,200 --> 00:47:57,360
Speaker 1: can change the frequencies. That's because all sound is actually

897
00:47:57,400 --> 00:47:59,719
Speaker 1: built up of a bunch of different frequencies, and you

898
00:47:59,760 --> 00:48:03,280
Speaker 1: can decomposed sound into those frequencies and say Bob Dylan

899
00:48:03,320 --> 00:48:06,040
Speaker 1: is more based than Lady Gaga or whatever. And so

900
00:48:06,080 --> 00:48:08,719
Speaker 1: in the same way, you can take any distribution and

901
00:48:08,840 --> 00:48:12,440
Speaker 1: you can break it down into basically sine waves and say, like,

902
00:48:12,760 --> 00:48:16,359
Speaker 1: what frequencies are more common in this distribution. And when

903
00:48:16,360 --> 00:48:18,520
Speaker 1: you do that and you look at the pattern of

904
00:48:18,680 --> 00:48:23,200
Speaker 1: die offs biologically, you don't see much evidence. There's like

905
00:48:23,480 --> 00:48:27,680
Speaker 1: maybe some weak evidence for periodic die offs every sixty

906
00:48:27,680 --> 00:48:31,520
Speaker 1: million years or every hundred and forty million years. Really

907
00:48:31,520 --> 00:48:35,000
Speaker 1: you don't see something every thirty million years, like this

908
00:48:35,080 --> 00:48:37,080
Speaker 1: cycle that we talked about where the Sun goes in

909
00:48:37,120 --> 00:48:39,600
Speaker 1: and out of the galactic plane that happens every thirty

910
00:48:39,640 --> 00:48:42,439
Speaker 1: million years, But we don't see a die off every

911
00:48:42,440 --> 00:48:44,719
Speaker 1: thirty million years. It doesn't look like life on Earth

912
00:48:44,719 --> 00:48:47,440
Speaker 1: has been wiped out by an asteroid impact every thirty

913
00:48:47,440 --> 00:48:50,600
Speaker 1: million years, right, So it doesn't seem like it's on

914
00:48:50,640 --> 00:48:53,560
Speaker 1: an exact schedule, But it seems like there's also the

915
00:48:53,640 --> 00:48:56,840
Speaker 1: chance that like it wouldn't happen every thirty million years,

916
00:48:57,080 --> 00:49:00,680
Speaker 1: but you know the chance of it happening every thirty

917
00:49:00,680 --> 00:49:04,200
Speaker 1: million years would slightly increase, but you would maybe skip

918
00:49:04,239 --> 00:49:08,200
Speaker 1: a bunch of potential die offs, because just by increasing

919
00:49:08,239 --> 00:49:11,000
Speaker 1: the chance of something doesn't guarantee that it's going to happen,

920
00:49:11,360 --> 00:49:13,919
Speaker 1: Which seems like a really difficult analysis to make because

921
00:49:13,960 --> 00:49:17,440
Speaker 1: we don't have, you know, that much time to work with,

922
00:49:17,480 --> 00:49:20,640
Speaker 1: because like the Earth is not like the oldest thing

923
00:49:20,719 --> 00:49:23,360
Speaker 1: in the universe. Yeah, don't understanding the fossil record and

924
00:49:23,360 --> 00:49:25,839
Speaker 1: our ability to analyze this thing doesn't really go much

925
00:49:25,880 --> 00:49:28,600
Speaker 1: further back than like five or six hundred million years

926
00:49:29,000 --> 00:49:31,720
Speaker 1: after like the Cambrian explosion and that kind of stuff.

927
00:49:31,760 --> 00:49:33,760
Speaker 1: But you're right, it could be sort of like every

928
00:49:33,800 --> 00:49:36,520
Speaker 1: thirty million years we play Russian roulette and sometimes we

929
00:49:36,600 --> 00:49:38,960
Speaker 1: win and sometimes we don't win. But then you would

930
00:49:39,000 --> 00:49:41,759
Speaker 1: see that appearing, right, even if it didn't happen every time,

931
00:49:42,040 --> 00:49:45,280
Speaker 1: you would see it appearing at that periodicity. It wouldn't

932
00:49:45,280 --> 00:49:47,879
Speaker 1: have to happen every time for this analysis to reveal it.

933
00:49:47,920 --> 00:49:50,000
Speaker 1: But you're right, Also, this is limited, like we don't

934
00:49:50,080 --> 00:49:52,799
Speaker 1: have that many examples, and so it could be that

935
00:49:52,800 --> 00:49:55,400
Speaker 1: it's there, we just haven't seen enough examples for it

936
00:49:55,440 --> 00:49:58,000
Speaker 1: to sort of rise out of the data statistically. But

937
00:49:58,080 --> 00:50:00,279
Speaker 1: currently when we look at the data, we can't say

938
00:50:00,280 --> 00:50:03,400
Speaker 1: that there's statistical evidence for any sort of periodicity in

939
00:50:03,440 --> 00:50:06,480
Speaker 1: the die off patterns of life on Earth. There's too

940
00:50:06,560 --> 00:50:10,080
Speaker 1: much noise, uh, and there's not really much evidence of

941
00:50:10,120 --> 00:50:13,920
Speaker 1: a signal. And maybe if we had many billions of

942
00:50:14,000 --> 00:50:16,600
Speaker 1: years to work with, we could have better data, but

943
00:50:16,719 --> 00:50:21,840
Speaker 1: we don't have that. And sadly, crocodiles and celia counts

944
00:50:21,960 --> 00:50:25,360
Speaker 1: and some of these really old species are not really

945
00:50:25,400 --> 00:50:30,120
Speaker 1: good at data collections. So exactly, the fascinating thing is

946
00:50:30,160 --> 00:50:33,200
Speaker 1: that all of these events, somebody was there, you know,

947
00:50:33,360 --> 00:50:36,360
Speaker 1: some life was there, some eyeball was around seeing these

948
00:50:36,400 --> 00:50:39,160
Speaker 1: things happen. Just like all of human history, though most

949
00:50:39,160 --> 00:50:42,480
Speaker 1: of it's forgotten, all of it was witnessed, right, there

950
00:50:42,520 --> 00:50:45,760
Speaker 1: was somebody who knew exactly what happened to humans twenty

951
00:50:45,800 --> 00:50:48,239
Speaker 1: thousand years ago. It's just all those people are dead

952
00:50:48,320 --> 00:50:50,640
Speaker 1: and they didn't write it down, and so all that

953
00:50:50,760 --> 00:50:54,440
Speaker 1: information is now lost. That's so frustrating. Sometimes some scientists

954
00:50:54,440 --> 00:50:56,279
Speaker 1: have turned to the interior of the Earth to try

955
00:50:56,280 --> 00:50:59,480
Speaker 1: to understand if there's evidence in the geologic record for

956
00:50:59,520 --> 00:51:03,040
Speaker 1: these impact, not just like did enough species die off,

957
00:51:03,120 --> 00:51:05,480
Speaker 1: because you know, maybe the asteroid hit, but it just

958
00:51:05,520 --> 00:51:08,120
Speaker 1: didn't cause a big die off. So instead they've looked

959
00:51:08,120 --> 00:51:10,800
Speaker 1: at like the Earth itself to see if there's evidence

960
00:51:10,920 --> 00:51:13,839
Speaker 1: for these impacts. And these guys were interested not just

961
00:51:13,960 --> 00:51:17,759
Speaker 1: in asteroid impacts, but also in slow geologic events that

962
00:51:17,800 --> 00:51:20,279
Speaker 1: could have caused die offs from within the Earth. Like

963
00:51:20,360 --> 00:51:23,560
Speaker 1: what if there's some crazy process inside the Earth that

964
00:51:23,600 --> 00:51:27,799
Speaker 1: causes supervolcanoes every fifty million years that causes a die

965
00:51:27,840 --> 00:51:31,640
Speaker 1: off or some other very like slow process that bubbles

966
00:51:31,719 --> 00:51:34,360
Speaker 1: up every x million years and we just haven't understood

967
00:51:34,400 --> 00:51:36,839
Speaker 1: it yet. You know, we've definitely discovered these kinds of

968
00:51:36,880 --> 00:51:39,480
Speaker 1: things in geology many times, so it's fun to sort

969
00:51:39,480 --> 00:51:43,040
Speaker 1: of imagine even deeper time processes. So these guys look

970
00:51:43,120 --> 00:51:46,440
Speaker 1: not just at evidence for asteroid collisions, but also like

971
00:51:46,680 --> 00:51:50,400
Speaker 1: just large marine extinctions or changes in the sea floor

972
00:51:50,719 --> 00:51:53,520
Speaker 1: or big volcanic events. And they did the same thing.

973
00:51:53,560 --> 00:51:55,640
Speaker 1: They did a four the analysis to look for a

974
00:51:55,760 --> 00:51:58,759
Speaker 1: repeating signal to see like is there a period to

975
00:51:58,840 --> 00:52:02,280
Speaker 1: sort of large theological events on the surface of the Earth.

976
00:52:02,360 --> 00:52:05,160
Speaker 1: And these guys in their paper, they actually claim to

977
00:52:05,320 --> 00:52:09,800
Speaker 1: discover a signal every twenty eight million years. They said

978
00:52:09,840 --> 00:52:14,960
Speaker 1: that there's strong statistical evidence for something bad happening every

979
00:52:15,040 --> 00:52:18,319
Speaker 1: twenty eight million years. But I actually have to take

980
00:52:18,400 --> 00:52:20,520
Speaker 1: issue with this paper. I read this paper and I

981
00:52:20,520 --> 00:52:23,880
Speaker 1: think that they've done these statistical analysis wrong. Oh boy,

982
00:52:24,160 --> 00:52:28,600
Speaker 1: some drama, getting ready for some some statistical analysis drama.

983
00:52:28,600 --> 00:52:30,719
Speaker 1: All right, let's go. Let's let's take them down. What

984
00:52:30,760 --> 00:52:33,360
Speaker 1: they did is they looked for the most common recurrence

985
00:52:33,440 --> 00:52:35,920
Speaker 1: and they found something abound twenty eight million years. But

986
00:52:36,040 --> 00:52:37,719
Speaker 1: you know, every time you're gonna look at your data,

987
00:52:37,719 --> 00:52:39,960
Speaker 1: you're gonna find something to be the most common. The

988
00:52:40,080 --> 00:52:43,399
Speaker 1: question is like, how likely is it to be that significant?

989
00:52:43,440 --> 00:52:45,080
Speaker 1: Is it really a big peak or is it just

990
00:52:45,080 --> 00:52:47,480
Speaker 1: sort of like the biggest peak among a bunch of

991
00:52:47,560 --> 00:52:50,080
Speaker 1: random noise. And so they tried to calculate this. They

992
00:52:50,080 --> 00:52:52,320
Speaker 1: try to say, like how likely is there to see

993
00:52:52,360 --> 00:52:55,080
Speaker 1: this big peak at twenty million years? Is this likely

994
00:52:55,120 --> 00:52:57,360
Speaker 1: to just be noise or is this something real? So

995
00:52:57,400 --> 00:52:59,400
Speaker 1: they ran a bunch of statistical tests to see, like

996
00:52:59,480 --> 00:53:01,520
Speaker 1: how like ease it to see something at twenty eight

997
00:53:01,560 --> 00:53:04,160
Speaker 1: million years, and they found those very unlikely to see

998
00:53:04,200 --> 00:53:07,080
Speaker 1: this kind of peak. And from that they conclude, oh,

999
00:53:07,120 --> 00:53:09,680
Speaker 1: while this must be real because it's very unlikely to

1000
00:53:09,760 --> 00:53:13,440
Speaker 1: generate this from just random noise. Problem with this method

1001
00:53:13,440 --> 00:53:15,840
Speaker 1: of statistical analysis is that they were only calculating the

1002
00:53:15,840 --> 00:53:18,840
Speaker 1: probability of seeing a peak from random events at twenty

1003
00:53:18,920 --> 00:53:21,759
Speaker 1: eight million years, whereas these random events also could have

1004
00:53:21,800 --> 00:53:24,399
Speaker 1: generated peaks at thirty million years and fifteen million years,

1005
00:53:24,440 --> 00:53:26,279
Speaker 1: and if they'd seen that in their data, they would

1006
00:53:26,280 --> 00:53:28,799
Speaker 1: have happily written a Nature paper about that as well.

1007
00:53:28,920 --> 00:53:31,600
Speaker 1: So I think they sort of overstate the case that

1008
00:53:31,680 --> 00:53:35,200
Speaker 1: this thing rises above the random noise. And in my view,

1009
00:53:35,280 --> 00:53:39,280
Speaker 1: there's no real statistical evidence here for the geologic record

1010
00:53:39,400 --> 00:53:42,520
Speaker 1: having any sort of period of major events, so speaking

1011
00:53:42,600 --> 00:53:46,360
Speaker 1: purely for a friend who may go a little cross

1012
00:53:46,400 --> 00:53:52,000
Speaker 1: side when discussing statistics. So essentially they're basically kind of

1013
00:53:52,120 --> 00:53:56,920
Speaker 1: pruning data points that would make this finding more likely,

1014
00:53:57,320 --> 00:54:01,040
Speaker 1: whereas if they included in their analysis all the data points,

1015
00:54:01,120 --> 00:54:04,319
Speaker 1: you would get a lot more evidence of noise. Yeah,

1016
00:54:04,320 --> 00:54:06,920
Speaker 1: it's like saying, what's the chance of getting a random

1017
00:54:06,960 --> 00:54:09,800
Speaker 1: peak at this number? It's pretty small. Well, what's the

1018
00:54:09,880 --> 00:54:12,239
Speaker 1: chance of getting a random peak at any number? It's

1019
00:54:12,239 --> 00:54:15,040
Speaker 1: going to be much much bigger, And that's the number

1020
00:54:15,040 --> 00:54:17,600
Speaker 1: they really need to be accounting for, because they would

1021
00:54:17,600 --> 00:54:20,279
Speaker 1: have accepted a peak but basically any number. Right now,

1022
00:54:20,320 --> 00:54:22,640
Speaker 1: it is interesting that the peak they get is just

1023
00:54:22,719 --> 00:54:26,279
Speaker 1: about at thirty million years. That is suggestive because we

1024
00:54:26,320 --> 00:54:28,839
Speaker 1: know there is this process where the Sun goes in

1025
00:54:28,880 --> 00:54:32,120
Speaker 1: and out of the galactic plane every thirty one million years,

1026
00:54:32,480 --> 00:54:35,080
Speaker 1: though they measure there's to be twenty eight million years.

1027
00:54:35,120 --> 00:54:36,920
Speaker 1: And that might not seem like a big difference to you,

1028
00:54:37,000 --> 00:54:41,040
Speaker 1: but three million years is not a short amount of time. Yeah,

1029
00:54:41,239 --> 00:54:45,640
Speaker 1: sounds circumstantial to me. Can you imagine if literature review

1030
00:54:45,760 --> 00:54:48,480
Speaker 1: was like a courtroom that you actually got to kind

1031
00:54:48,520 --> 00:54:52,760
Speaker 1: of be a big fancy city lawyer in court arguing

1032
00:54:52,840 --> 00:54:56,000
Speaker 1: for against statistical analysis. I think that would make science

1033
00:54:56,040 --> 00:54:59,920
Speaker 1: a lot more interesting. It would probably make it for

1034
00:55:00,000 --> 00:55:03,080
Speaker 1: a lot more deep grudges also, and you know, for

1035
00:55:03,120 --> 00:55:06,520
Speaker 1: answering our question about whether there's a pattern to asteroid

1036
00:55:06,560 --> 00:55:09,200
Speaker 1: impacts on Earth, remember that this paper is thinking about

1037
00:55:09,239 --> 00:55:13,240
Speaker 1: all geological events, supervolcanoes and all sorts of other stuff.

1038
00:55:13,239 --> 00:55:15,040
Speaker 1: And if you look at most of these events the

1039
00:55:15,080 --> 00:55:18,960
Speaker 1: boundaries between geological time scales. For example, only the event

1040
00:55:19,000 --> 00:55:22,360
Speaker 1: it's sixty five million years ago in the geological record

1041
00:55:22,600 --> 00:55:25,360
Speaker 1: shows a significant impact. You know, we can see like

1042
00:55:25,440 --> 00:55:28,200
Speaker 1: the ash and the dust from that impact in the record.

1043
00:55:28,200 --> 00:55:30,560
Speaker 1: If you dig down into the earth, you can find

1044
00:55:30,640 --> 00:55:34,400
Speaker 1: that and see the impact the other transition periods and

1045
00:55:34,440 --> 00:55:36,680
Speaker 1: the die offs that don't seem to align with any

1046
00:55:36,760 --> 00:55:39,680
Speaker 1: asteroid impact. There's no like event. We can find no

1047
00:55:39,840 --> 00:55:43,760
Speaker 1: evidence of ash and dust, so it seems pretty loose.

1048
00:55:43,840 --> 00:55:45,600
Speaker 1: As far as we can tell right now, there is

1049
00:55:45,680 --> 00:55:49,640
Speaker 1: no evidence of periodic asteroid impact on Earth, which is,

1050
00:55:49,680 --> 00:55:51,759
Speaker 1: you know, good news because it means that another one

1051
00:55:51,840 --> 00:55:54,440
Speaker 1: might not be coming. But it's bad news because it

1052
00:55:54,640 --> 00:55:57,520
Speaker 1: means they might just be unpredictable. I mean, it's also

1053
00:55:57,600 --> 00:56:00,480
Speaker 1: bad news if I really want to cancel my dentist

1054
00:56:00,520 --> 00:56:04,799
Speaker 1: appointment and the next million years or so, you know.

1055
00:56:05,000 --> 00:56:08,239
Speaker 1: I think another thing is that when the big one

1056
00:56:08,360 --> 00:56:11,640
Speaker 1: hit Earth and you know, killed off the dinosaurs. Of

1057
00:56:11,680 --> 00:56:13,719
Speaker 1: course a little more complicated than that. I mean, there

1058
00:56:13,719 --> 00:56:18,160
Speaker 1: were also other things happening at the time, other geological

1059
00:56:18,200 --> 00:56:22,760
Speaker 1: activity that was contributing to the extinction. So it wasn't

1060
00:56:22,840 --> 00:56:26,080
Speaker 1: just the asteroid. They also think that there was volcanic

1061
00:56:26,120 --> 00:56:29,600
Speaker 1: activity that had nothing to do with the asteroid that

1062
00:56:29,800 --> 00:56:33,920
Speaker 1: was causing an impact on the environment. And so it

1063
00:56:33,960 --> 00:56:38,479
Speaker 1: was just this kind of like poorly timed asteroid that

1064
00:56:39,000 --> 00:56:41,239
Speaker 1: kind of helped put a nail in the coffin of

1065
00:56:41,760 --> 00:56:47,359
Speaker 1: an already sort of precarious situation for the dinosaurs, and

1066
00:56:47,440 --> 00:56:49,840
Speaker 1: so yeah, I think it seems like it'd be a

1067
00:56:49,880 --> 00:56:55,319
Speaker 1: little too tidy in terms of finding. You know that

1068
00:56:55,440 --> 00:56:58,080
Speaker 1: every thirty million years we get hit by an asteroid

1069
00:56:58,120 --> 00:57:01,200
Speaker 1: and all the animals, you know, go oh no, except

1070
00:57:01,280 --> 00:57:03,840
Speaker 1: for a lucky few of them that end up surviving.

1071
00:57:03,920 --> 00:57:07,440
Speaker 1: But it does seem like the actual picture of it

1072
00:57:07,480 --> 00:57:09,759
Speaker 1: would be a lot messier, have to do with a

1073
00:57:09,760 --> 00:57:14,760
Speaker 1: lot more kind of just a confluence of environmental factors,

1074
00:57:14,800 --> 00:57:17,560
Speaker 1: both on Earth and maybe you know, outside of Earth,

1075
00:57:17,680 --> 00:57:21,720
Speaker 1: rather than just one kind of convenient every thirty million

1076
00:57:21,800 --> 00:57:25,240
Speaker 1: years asteroids and backdown. You sound like the asteroids defense

1077
00:57:25,360 --> 00:57:27,760
Speaker 1: lawyer saying, hey, look, it wasn't my client. Even if

1078
00:57:27,800 --> 00:57:30,200
Speaker 1: they were there, there was other stuff going on. I

1079
00:57:30,360 --> 00:57:34,080
Speaker 1: may be a simple country lawyer, but the evidence that

1080
00:57:34,200 --> 00:57:39,080
Speaker 1: my asteroid was anywhere near those dinosaurs is purely circumstantial.

1081
00:57:39,240 --> 00:57:41,160
Speaker 1: I'm going to call in Daniel Whiteson to argue about

1082
00:57:41,160 --> 00:57:44,960
Speaker 1: the statistical analysis of this paper. Al Right, well, I

1083
00:57:45,000 --> 00:57:48,000
Speaker 1: think you can rest easy then, knowing that a big

1084
00:57:48,040 --> 00:57:52,400
Speaker 1: asteroid may not necessarily be on way to pulverize all

1085
00:57:52,440 --> 00:57:56,760
Speaker 1: of us. That is the most like lackluster optimistic thing

1086
00:57:56,800 --> 00:57:59,320
Speaker 1: I've ever heard. It's like you can rest easy knowing

1087
00:57:59,400 --> 00:58:03,360
Speaker 1: that you not die a random and horrible death along

1088
00:58:03,400 --> 00:58:06,640
Speaker 1: with everyone else on Earth. But hey, you know, glass

1089
00:58:06,680 --> 00:58:09,320
Speaker 1: half full. You may not die of predictable periodic death,

1090
00:58:09,440 --> 00:58:12,760
Speaker 1: but you may actually die a random, horrible death because

1091
00:58:13,120 --> 00:58:17,320
Speaker 1: comments and asteroids are unpredictable, and especially comets are really

1092
00:58:17,320 --> 00:58:20,000
Speaker 1: a source of danger. And we need to keep funding

1093
00:58:20,000 --> 00:58:22,240
Speaker 1: those telescopes to look out there. We need to keep

1094
00:58:22,280 --> 00:58:26,000
Speaker 1: developing these technologies to divert these objects if they do

1095
00:58:26,080 --> 00:58:29,320
Speaker 1: come towards our wonderful planet. Oh, I see, this is

1096
00:58:29,360 --> 00:58:32,800
Speaker 1: why you're blaming the asteroids. This is a shakedown for

1097
00:58:32,920 --> 00:58:36,120
Speaker 1: funding for science, just trying to save the planet. I mean,

1098
00:58:36,240 --> 00:58:39,200
Speaker 1: just a little little thing like saving the planet. How convenient?

1099
00:58:40,680 --> 00:58:42,600
Speaker 1: All right, Well, thank you Katy very much for joining

1100
00:58:42,760 --> 00:58:46,360
Speaker 1: us on this optimistic view of our situation in the

1101
00:58:46,440 --> 00:58:50,640
Speaker 1: Solar System and offering your full throw defense of asteroids.

1102
00:58:50,960 --> 00:58:54,200
Speaker 1: And thanks everybody for listening to another deep dive into

1103
00:58:54,240 --> 00:58:57,480
Speaker 1: the deep history of life on Earth. Thanks for joining us.

1104
00:58:57,480 --> 00:59:07,480
Speaker 1: Tune in next time, yea, thanks for listening, and remember

1105
00:59:07,520 --> 00:59:10,360
Speaker 1: that Daniel and Jorge explain the universe is a production

1106
00:59:10,440 --> 00:59:13,960
Speaker 1: of I heart radio. For more podcast from my heart Radio,

1107
00:59:14,120 --> 00:59:17,680
Speaker 1: visit the i heart Radio app, Apple Podcasts, or wherever

1108
00:59:17,800 --> 00:59:19,480
Speaker 1: you listen to your favorite shows.