WEBVTT - Listener Questions #18

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<v Speaker 1>I'd like us to quickly explore deep into space. Can

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<v Speaker 1>gravity slingshots help us win that race?

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<v Speaker 2>If ancient humans killed off the giant kangaroo, why didn't

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<v Speaker 2>we kill off the African elephant too?

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<v Speaker 1>How much do tiny black holes like to eat? If

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<v Speaker 1>I adopt one, will it nap at my feet?

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<v Speaker 2>Whatever questions keep you up at night, Daniel and Kelly's answers.

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<v Speaker 3>Will make it right.

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<v Speaker 1>Welcome to Daniel and Kelly's extraordinarily Curious universe.

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<v Speaker 3>Hello, I'm Kelly Waiter Smith.

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<v Speaker 2>I study parasites and space, and I am excited to

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<v Speaker 2>talk about charismatic megafauna today.

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<v Speaker 1>Hi. I'm Daniel. I'm a particle physicist, and I never

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<v Speaker 1>wanted a willing mamoth as a pet.

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<v Speaker 2>Oh you No, I didn't either. I don't think I

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<v Speaker 2>want anything bigger than the goats that we have right now?

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<v Speaker 1>What about a goat sized black hole? Or do goats

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<v Speaker 1>basically operate as black holes because they eat everything?

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<v Speaker 3>You know?

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<v Speaker 2>Our goats are surprisingly picky about what they eat, which

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<v Speaker 2>I'm winding a little frustrated because I was like, Oh,

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<v Speaker 2>we're gonna get walking garbage disposals, but ours are like no,

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<v Speaker 2>I don't want that.

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<v Speaker 3>I don't want that either, So your goats are not

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<v Speaker 3>the goat.

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<v Speaker 2>I wouldn't say that. They are definitely the greatest of

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<v Speaker 2>all time. And one of them is named Greatest of

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<v Speaker 2>all Time aka Kevin for short. That's the full name

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<v Speaker 2>that's on its certificate, because we let children name our goats.

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<v Speaker 2>So one of them is the goat literally literally. But

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<v Speaker 2>I had a particularly negative experience with wildlife this morning.

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<v Speaker 2>I just walking up the hill accidentally smacked a wasp

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<v Speaker 2>of some sort and my thumb is expanding. Oh and

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<v Speaker 2>we'll see how big it is by the end of

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<v Speaker 2>the episode. But I wanted to focus on more positive interactions.

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<v Speaker 2>Since we're gonna be talking like Africa's charismatic wildlife, I

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<v Speaker 2>wanted to know what is the most like awe inspiring

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<v Speaker 2>experience you've had with an animal in nature?

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<v Speaker 3>Because you and Katrina hike, you're like outdoor people.

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<v Speaker 1>I think one of the most incredible experiences I've had

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<v Speaker 1>was seeing a mountain lion close up. Who I grew

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<v Speaker 1>up in the mountains of northern New Mexico, and there

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<v Speaker 1>were mountain lions because they were mountains, and you know,

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<v Speaker 1>sometimes you'd get up in the morning and you'd see

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<v Speaker 1>their pop rinks in the snow. But one time I

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<v Speaker 1>actually did spot one, and it's incredible how much they

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<v Speaker 1>are like housecats, you know, in their smoothness and their

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<v Speaker 1>their feline charisma, but also how terrifyingly huge they are,

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<v Speaker 1>because I've often wondered, like, what would my housecat do

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<v Speaker 1>if it weighed a thousand pounds? And now I know

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<v Speaker 1>the answer is it would eat me.

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<v Speaker 2>I mean, most of the time, mountain lions don't go

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<v Speaker 2>after people. I want to clear the mountain lion's name,

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<v Speaker 2>and if anybody wants to read more about that, they

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<v Speaker 2>should check out more ark Elbrock's book on mountain lions.

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<v Speaker 2>But yeah, so that is beautiful. So like, did you

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<v Speaker 2>see it at a distance where like how far away

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<v Speaker 2>was it?

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<v Speaker 1>It was like maybe eighty feet or something. My parents'

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<v Speaker 1>backyard was right up against National Forest and so there

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<v Speaker 1>was just like a lot of trees and canyons back there,

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<v Speaker 1>and I saw one walking through the trees and I

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<v Speaker 1>saw it and it saw me, and we like shared

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<v Speaker 1>a little moment, and I was like, I'm on a

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<v Speaker 1>tiptoe back inside. You can have the whole outdoors.

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<v Speaker 2>It's all yours now, buddy, and I assumed that he did.

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<v Speaker 2>It did not approach you or anything like that.

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<v Speaker 1>No, no, it did not, and I'm very happy that

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<v Speaker 1>it went on its way. But it reminds me of

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<v Speaker 1>this incredible story I heard about European lions. You know,

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<v Speaker 1>the lions used to roam Europe also, but they were

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<v Speaker 1>killed off many, many years ago. And the story I

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<v Speaker 1>heard is that for a long time there was a

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<v Speaker 1>question about European lions. Do they have mains like African

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<v Speaker 1>lions or not like North American lions. And we answered

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<v Speaker 1>this question through cave drawings. People found drawings of lions

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<v Speaker 1>from tens of thousands of years ago from Paleolithic artists,

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<v Speaker 1>and it's basically like a lab book and they don't

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<v Speaker 1>have mains, and you can see like hunting pears even

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<v Speaker 1>And so that's incredible to me that, like humans, tens

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<v Speaker 1>of thousands of years ago answered our current science question.

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<v Speaker 2>Okay, so that is amazing, but how does the absence

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<v Speaker 2>of seeing mains like so, you know, in Africa, when

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<v Speaker 2>you get groups that are hunting, it's usually groups of

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<v Speaker 2>females that are hunting. The females do most of the hunting,

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<v Speaker 2>So how do you know that, you know, the worthless

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<v Speaker 2>males just were weren't drawn on the insides of the caves.

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<v Speaker 1>Yeah, great question. I shouldn't have said hunting pair. I

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<v Speaker 1>think they had some reason to believe this is like

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<v Speaker 1>a family unit. But it sort of connects us over

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<v Speaker 1>space and time to you know, early humans who are

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<v Speaker 1>also awed by the majesty of megafauna.

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<v Speaker 3>Yes, absolutely, very cool.

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<v Speaker 2>And when I asked you that question, I assumed you

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<v Speaker 2>we're going to pick megafauna because almost almost everyone picks,

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<v Speaker 2>you know, some large mammal, the largest mammal they've ever seen,

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<v Speaker 2>is usually the answer to that question.

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<v Speaker 1>Oh, I see, You've asked other people this question, and

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<v Speaker 1>nobody has said the time I saw a rat in

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<v Speaker 1>my kitchen.

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<v Speaker 3>Well, of course not No, no one has said that.

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<v Speaker 2>But I think my moment was I was in the

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<v Speaker 2>woods and I was helping a friend with the snake survey,

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<v Speaker 2>and a bunch of wood frogs had recently like metamorphosed

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<v Speaker 2>from tadpoles into like adults, but they were are you know,

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<v Speaker 2>into the landstage.

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<v Speaker 3>But they were really tiny.

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<v Speaker 2>And there were literally hundreds of them, and I noticed

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<v Speaker 2>them because I like moved my foot forward and all

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<v Speaker 2>of these tiny things hopped out of the way.

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<v Speaker 1>Oh my god.

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<v Speaker 2>And I realized, like, oh my gosh, I'm surrounded by

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<v Speaker 2>like hundreds of little froglets, these little tiny frogs, and

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<v Speaker 2>I just sat down and like the sun was coming

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<v Speaker 2>through the trees and just the right way that it

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<v Speaker 2>kind of had like a magical feeling. And every time

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<v Speaker 2>I'd sort of move my hand, all of these little

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<v Speaker 2>froglets would like hop around, and it was just like,

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<v Speaker 2>I don't know, it was magic. It was like being

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<v Speaker 2>in some sort of a fairy book or something. And

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<v Speaker 2>I think for me that was that was my moment.

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<v Speaker 1>Well, I have a moment I recall from being in

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<v Speaker 1>your neck of the woods. Oh, it was more of

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<v Speaker 1>a horror story than a magical moment. Katrina and I

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<v Speaker 1>were hiking and backpacking, I think it was in the

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<v Speaker 1>Blue Ridge Mountains, and we set up our camp and

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<v Speaker 1>we had a nice campfire, and at the end of

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<v Speaker 1>the evening we were ready to go back to our tent,

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<v Speaker 1>and it was only then that we noticed that the

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<v Speaker 1>ground just outside the extent of the fire was covered

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<v Speaker 1>in daddy long legs. There were like millions and millions

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<v Speaker 1>of them, and they were crawling all over our tent

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<v Speaker 1>and everywhere. It was incredible. We were so grateful that

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<v Speaker 1>we had zipped our tent closed, so we like sprained

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<v Speaker 1>it back to the tent open it, jumped in closed it,

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<v Speaker 1>and was just like terrified of the carpet of Daddy

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<v Speaker 1>long legs that were outside. I was like, wow, Virginia's crazy.

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<v Speaker 3>But they can't hurt you.

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<v Speaker 1>They can't hurt you. But I'm still not gonna like

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<v Speaker 1>lie down and have Daddy long legs crawl all over me.

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<v Speaker 2>All right, Well I don't I feel like I'm not

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<v Speaker 2>really feeling.

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<v Speaker 1>All right, Zach, you are free to release Daddy long

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<v Speaker 1>legs all over Kelly was she's asleep. Sure, sure, Wow, amazing.

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<v Speaker 1>You don't have the same reaction to spiders as other

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<v Speaker 1>people do.

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<v Speaker 2>Huh, Well, Daddy long legs aren't really spiders.

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<v Speaker 1>Oh my gosh. Wow, and that scientific knowledge puts you

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<v Speaker 1>at ease, it does.

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<v Speaker 2>Let me make sure that's right. Our Daddy long legs spiders.

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<v Speaker 2>I think there are racknids. Oh maybe they do still

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<v Speaker 2>count as spiders. Yeah, all right, so sorry, I guess

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<v Speaker 2>they are still Teddy long legs are still see.

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<v Speaker 1>I told you they were creepy like that makes a.

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<v Speaker 2>Difference, all right, So sorry, you were right, daddy, long

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<v Speaker 2>legs looks like they are spiders. But I do feel

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<v Speaker 2>like knowledge makes a huge difference. So we've got these

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<v Speaker 2>they're called rabid wolf spiders, bad name, right, and they're

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<v Speaker 2>like big and they do look kind of scary. And

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<v Speaker 2>when I first moved here, I freaked out because my

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<v Speaker 2>son likes to roll around in the grass and these

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<v Speaker 2>are like grass spiders that are in the grass, and

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<v Speaker 2>so he'd roll around in it. I always see like

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<v Speaker 2>a big spider running away and it really freaked me out.

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<v Speaker 2>But I read about them, and now I'm not scared

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<v Speaker 2>of them, like they're they're not gonna go after my son.

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<v Speaker 3>It's fine.

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<v Speaker 2>I do feel like knowledge makes a big difference in

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<v Speaker 2>my fear outside in general.

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<v Speaker 1>You're totally right, and of course, knowledge is our business.

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<v Speaker 1>We're here to help everybody understand the universe better and

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<v Speaker 1>be less afraid of it, or maybe appropriately afraid of it.

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<v Speaker 1>So let's get into it, because today we're not here

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<v Speaker 1>just to talk about my experiences with spiders and Kelly's

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<v Speaker 1>magical moment with the frogs. We're here to talk about

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<v Speaker 1>your questions about the universe, things you wonder about, places

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<v Speaker 1>where you wish you had more knowledge. So we regularly

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<v Speaker 1>ask our listeners to send in their questions, and we'd

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<v Speaker 1>love to hear from you. Please write to us to

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<v Speaker 1>questions at Danielankelly dot org. We always write back to everybody,

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<v Speaker 1>and sometimes we pick questions to answer here on the

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<v Speaker 1>pod because we think a lot of people might be

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<v Speaker 1>interested in the answer, or because I think it'd be

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<v Speaker 1>fun to joke about it with Kelly.

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<v Speaker 2>Or because when I get the EMO from you, I

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<v Speaker 2>don't know the answer and I need to stall for

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<v Speaker 2>Time's you go.

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<v Speaker 3>That's the other reason.

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<v Speaker 1>So, speaking of stalling for time, here's our first question,

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<v Speaker 1>which is about how to quickly explore the outer Solar

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<v Speaker 1>System using gravity's help.

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<v Speaker 4>Hi, Daniel and Kelly. I was thinking about how we

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<v Speaker 4>use gravitational slingshots permissions such as Voyager, Cassini and New

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<v Speaker 4>Horizons as we venture further into the Solar System. Would

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<v Speaker 4>we use this method for human credmissions and what forces

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<v Speaker 4>would the crew feel if they were slingshotted to their destination? Thanks?

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<v Speaker 1>All right, and that question was from Rob Pixley. Rob,

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<v Speaker 1>thank you very much for writing in. Kelly, you're an

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<v Speaker 1>expert on space and exploration. What do you think about this?

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<v Speaker 2>Well, I believe that gravitational slingshots are when you use

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<v Speaker 2>massive objects to gain some speed. But I'm going to

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<v Speaker 2>wait for you to give some more information. But when

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<v Speaker 2>I read this, it reminded me of Jules Verne's and

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<v Speaker 2>I can never say his name right.

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<v Speaker 3>Thank you, because he's French. Okay, all right, that guy,

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<v Speaker 3>That French guy.

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<v Speaker 2>He wrote a book From the Earth to the Moon,

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<v Speaker 2>and it was about a Baltimore gun club who decided

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<v Speaker 2>they were going to build a giant gun and shoot

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<v Speaker 2>people to the moon. And it works. But the problem is, actually,

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<v Speaker 2>if you were to calculate how many gs the crew

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<v Speaker 2>would have felt, they would have been probably like liquefied

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<v Speaker 2>in chapter twenty on the Way to the Moon. They

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<v Speaker 2>wouldn't have made it. So let's hear about gravitational slingshots.

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<v Speaker 2>Would this kill humans or nothing?

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<v Speaker 1>Gravitational slingshots are super awesome. They are a way to

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<v Speaker 1>boost your speed and change your direction without using any fuel.

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<v Speaker 1>You know, one of the big issues for getting around

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<v Speaker 1>the Solar System or getting around the universe is that

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<v Speaker 1>fuel is heavy and if you use fuel to propel yourself.

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<v Speaker 1>You need fuel to help you push that fuel, and

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<v Speaker 1>then you need more fuel to help you push that fuel,

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<v Speaker 1>and pretty soon you have a gas tank the size

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<v Speaker 1>of Jupiter just to get anywhere. So it's very nice

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<v Speaker 1>if you can navigate the universe without using fuel, because

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<v Speaker 1>then you don't have the additional mass and then need

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<v Speaker 1>to propel that all that stuff. So for decades, NASA

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<v Speaker 1>and other folks have been using this technique called a

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<v Speaker 1>gravitational slingshot, which essentially steals a little bit of speed

0:10:53.960 --> 0:10:56.800
<v Speaker 1>from a planet or a moon. The way it works

0:10:56.840 --> 0:10:59.960
<v Speaker 1>is you can approach a big planet and it's gravity

0:11:00.080 --> 0:11:03.320
<v Speaker 1>you will change your direction. So for example, say you're

0:11:03.360 --> 0:11:06.600
<v Speaker 1>just coasting, you have no rockets on, and you're approaching Jupiter,

0:11:06.800 --> 0:11:08.839
<v Speaker 1>and you swing around the back of Jupiter and come

0:11:08.880 --> 0:11:11.840
<v Speaker 1>out the other side. Now you're going in a new direction. Right.

0:11:12.280 --> 0:11:15.760
<v Speaker 1>That's not something you can otherwise accomplish, usually without burning

0:11:15.800 --> 0:11:18.839
<v Speaker 1>some fuel, without thrusters, because a change in direction, even

0:11:18.880 --> 0:11:21.880
<v Speaker 1>if your overall magnitude is the same, is still an acceleration.

0:11:22.360 --> 0:11:24.600
<v Speaker 1>To change your direction in space, you've got to have

0:11:24.679 --> 0:11:27.679
<v Speaker 1>some acceleration. Somebody's got to pull on you. So basically

0:11:27.760 --> 0:11:29.800
<v Speaker 1>you use the gravity of the planet to pull on

0:11:29.920 --> 0:11:31.959
<v Speaker 1>you and you can even come out the other side,

0:11:32.040 --> 0:11:34.400
<v Speaker 1>not just with a change in direction, but with a

0:11:34.480 --> 0:11:37.160
<v Speaker 1>net increase in speed. And that's why it's called a

0:11:37.200 --> 0:11:38.720
<v Speaker 1>gravitational slingshot.

0:11:38.880 --> 0:11:41.800
<v Speaker 2>Well, I don't think we've ever used this on a

0:11:41.920 --> 0:11:44.760
<v Speaker 2>vehicle carrying humans, because the only option would be the

0:11:44.800 --> 0:11:47.080
<v Speaker 2>trip to the Moon. But have we used this for

0:11:47.120 --> 0:11:49.160
<v Speaker 2>our rovers or anything or probes.

0:11:49.320 --> 0:11:52.400
<v Speaker 1>We've used it for lots of probes, absolutely, because a

0:11:52.400 --> 0:11:54.640
<v Speaker 1>lot of times we don't have the fuel to get

0:11:54.640 --> 0:11:56.920
<v Speaker 1>them all the way out to the outer Solar System,

0:11:57.240 --> 0:11:59.600
<v Speaker 1>and we want to keep them light and it saves fuel.

0:12:00.040 --> 0:12:02.000
<v Speaker 1>And then also you get to add like another planet

0:12:02.080 --> 0:12:03.360
<v Speaker 1>on your trip. You're like, hey, I want to go

0:12:03.360 --> 0:12:05.360
<v Speaker 1>to Saturn, but I'd like to swing by Mars on

0:12:05.400 --> 0:12:07.199
<v Speaker 1>the way, Or I'd like to go to Neptune. Can

0:12:07.240 --> 0:12:09.720
<v Speaker 1>we stop by Jupiter? And then you also get to

0:12:09.720 --> 0:12:11.800
<v Speaker 1>take pictures of Jupiter because you know, none of these

0:12:11.840 --> 0:12:13.880
<v Speaker 1>things are so well explored that like one more trip

0:12:13.960 --> 0:12:16.600
<v Speaker 1>is boring, you know. Yeah, so that's like a bonus

0:12:16.640 --> 0:12:18.800
<v Speaker 1>for these things. And I think the physics of it

0:12:18.840 --> 0:12:21.440
<v Speaker 1>is really fascinating because it's a little bit counterintuitive, like

0:12:21.520 --> 0:12:25.280
<v Speaker 1>it feels like free energy, Like where is this speed

0:12:25.400 --> 0:12:27.680
<v Speaker 1>coming from? And the answer to that question is that

0:12:27.679 --> 0:12:30.439
<v Speaker 1>you're really taking that speed from the planet. Like if

0:12:30.440 --> 0:12:34.120
<v Speaker 1>you swing by Jupiter, it changes your direction, it accelerates you,

0:12:34.320 --> 0:12:37.520
<v Speaker 1>and it effectively slows down. It slows down in its

0:12:37.600 --> 0:12:40.920
<v Speaker 1>orbit around the Sun. So, for example, if you take

0:12:40.960 --> 0:12:43.520
<v Speaker 1>a normal space probe and you swing it around Jupiter

0:12:43.640 --> 0:12:46.880
<v Speaker 1>and it gets sped up in the process, Jupiter slows down,

0:12:46.920 --> 0:12:49.880
<v Speaker 1>but just by a tiny little bit because the mass

0:12:49.880 --> 0:12:52.839
<v Speaker 1>of Jupiter is so huge compared to the mass of

0:12:52.880 --> 0:12:56.200
<v Speaker 1>the probe that it loses I did this calculation one

0:12:56.240 --> 0:12:59.480
<v Speaker 1>times ten to the negative twenty five kilometers per second

0:12:59.520 --> 0:13:03.560
<v Speaker 1>of its flow, so basically negligible. However, if you scale

0:13:03.600 --> 0:13:06.120
<v Speaker 1>this up and you did like, you know, ten to

0:13:06.160 --> 0:13:09.040
<v Speaker 1>the twenty five space probes, because you want to explore

0:13:09.040 --> 0:13:12.199
<v Speaker 1>the whole galaxy, you might start having an impact on Jupiter.

0:13:12.240 --> 0:13:15.600
<v Speaker 1>But basically, think about Jupiter as a huge battery of

0:13:15.760 --> 0:13:18.560
<v Speaker 1>momentum and you're tapping into that a little bit and

0:13:18.600 --> 0:13:20.040
<v Speaker 1>adding it to your space probes.

0:13:20.200 --> 0:13:23.440
<v Speaker 2>So if an aggressive alien civilization wanted to screw up

0:13:23.480 --> 0:13:28.120
<v Speaker 2>our solar system, could they just send probes by Jupiter

0:13:28.280 --> 0:13:30.560
<v Speaker 2>enough times to get it to sort of move around

0:13:30.600 --> 0:13:32.040
<v Speaker 2>and rek havoc on the rest of Us.

0:13:32.440 --> 0:13:34.240
<v Speaker 1>I guess they could. But you know, if they were

0:13:34.280 --> 0:13:36.800
<v Speaker 1>capable of doing that, they should just like nudge an

0:13:36.840 --> 0:13:39.800
<v Speaker 1>asteroid towards Earth. I mean, I'm not giving advice to

0:13:40.120 --> 0:13:44.400
<v Speaker 1>malevolent aliens. Okay, sounds like I am, so you please

0:13:44.559 --> 0:13:48.240
<v Speaker 1>if you are malevolent aliens, don't do this, or anybody

0:13:48.280 --> 0:13:50.160
<v Speaker 1>shouldn't do this. But yeah, the most dangerous thing you

0:13:50.160 --> 0:13:52.600
<v Speaker 1>could do in the Solar system is nudge a comet,

0:13:52.640 --> 0:13:55.000
<v Speaker 1>for example, because comments by the time they get to

0:13:55.040 --> 0:13:57.640
<v Speaker 1>the inner Solar System are going really really fast because

0:13:57.640 --> 0:14:00.160
<v Speaker 1>they fall from so far away, and they're really are

0:14:00.280 --> 0:14:02.760
<v Speaker 1>to see in advance because their periods are so long.

0:14:03.280 --> 0:14:05.440
<v Speaker 1>So yeah, nudging a comet would be the most dangerous thing.

0:14:05.480 --> 0:14:08.000
<v Speaker 1>I guess the most subtle thing would be tweaking Jupiter.

0:14:08.120 --> 0:14:10.560
<v Speaker 1>That would be a cool basis for a science fiction novel.

0:14:10.600 --> 0:14:12.280
<v Speaker 1>Get on it, Daniel, And for those of you who

0:14:12.360 --> 0:14:15.200
<v Speaker 1>still trying to like Grock, how this works? You know?

0:14:15.280 --> 0:14:18.520
<v Speaker 1>Another analogy is like think about a moving train and

0:14:18.559 --> 0:14:21.000
<v Speaker 1>you have a tennis ball. If you throw your tennis

0:14:21.000 --> 0:14:23.960
<v Speaker 1>ball against the front of the train. Then the train's

0:14:24.000 --> 0:14:26.560
<v Speaker 1>velocity gets added to the tennis ball's velocity when it

0:14:26.560 --> 0:14:29.200
<v Speaker 1>bounces off, right, So now it comes back, it's going

0:14:29.280 --> 0:14:31.720
<v Speaker 1>not just the same velocity as it was when it

0:14:31.800 --> 0:14:33.960
<v Speaker 1>hit the train. Like if you bounce the tennis ball

0:14:33.960 --> 0:14:35.880
<v Speaker 1>against a wall, it comes back with the same speed.

0:14:36.040 --> 0:14:38.200
<v Speaker 1>If you bounce a tennis ball against a train rushing

0:14:38.240 --> 0:14:40.760
<v Speaker 1>at you, it comes back much much faster. It slows

0:14:40.800 --> 0:14:43.000
<v Speaker 1>down the train a tiny little bit, nobody's ever going

0:14:43.040 --> 0:14:45.480
<v Speaker 1>to notice, but it speeds up the tennis ball. And

0:14:45.520 --> 0:14:48.800
<v Speaker 1>so it's this huge mass ratio that makes this possible.

0:14:49.080 --> 0:14:52.040
<v Speaker 2>All right, So how fast does this speed up happen?

0:14:52.080 --> 0:14:53.440
<v Speaker 2>And is it going to be fast enough that you're

0:14:53.440 --> 0:14:55.920
<v Speaker 2>going to liquefy the humans inside?

0:14:56.360 --> 0:14:59.200
<v Speaker 1>Right? So two really interesting questions, and that's really what

0:14:59.280 --> 0:15:02.040
<v Speaker 1>Rob was asking about. So number one, this isn't a

0:15:02.080 --> 0:15:04.800
<v Speaker 1>great idea for human missions, but not because of the

0:15:04.800 --> 0:15:07.640
<v Speaker 1>g forces, but because usually it involves going pretty far

0:15:07.720 --> 0:15:10.720
<v Speaker 1>out of your way. Like you're sending a probe to Pluto.

0:15:11.000 --> 0:15:12.800
<v Speaker 1>You know it's going to take forever to get there.

0:15:13.000 --> 0:15:15.160
<v Speaker 1>If you can make it lighter by stopping by Saturn

0:15:15.200 --> 0:15:17.080
<v Speaker 1>on the way, you don't really care if it's going

0:15:17.160 --> 0:15:19.240
<v Speaker 1>to slow you down by five years, because it can

0:15:19.240 --> 0:15:21.600
<v Speaker 1>slow you down by five years, so it's a more

0:15:21.600 --> 0:15:24.440
<v Speaker 1>economical way to get this speed, But often it requires

0:15:24.440 --> 0:15:26.640
<v Speaker 1>going really far out of your way, and if you're

0:15:26.680 --> 0:15:29.200
<v Speaker 1>doing space missions, the goal is to get there fast,

0:15:29.240 --> 0:15:31.560
<v Speaker 1>to spend less time in space, less time exposed to

0:15:31.600 --> 0:15:34.880
<v Speaker 1>low gravity, less time exposed to radiation, all this kind

0:15:34.920 --> 0:15:38.240
<v Speaker 1>of stuff. Now, sometimes it can work if the Solar

0:15:38.280 --> 0:15:40.840
<v Speaker 1>system is just right. You know, if you want to

0:15:40.880 --> 0:15:43.280
<v Speaker 1>get to Saturn and Jupiter happens to be in just

0:15:43.320 --> 0:15:46.080
<v Speaker 1>the right place, then maybe a flyby of Jupiter can

0:15:46.320 --> 0:15:50.040
<v Speaker 1>help you get to Saturn faster. But usually you just

0:15:50.080 --> 0:15:52.880
<v Speaker 1>want to go directly there, and so you want chemical

0:15:52.960 --> 0:15:57.160
<v Speaker 1>rockets or ion thrusters or fusion power or something. So

0:15:57.240 --> 0:15:59.680
<v Speaker 1>this is good for long missions where you don't really

0:15:59.680 --> 0:16:02.000
<v Speaker 1>care how long it takes, which is not what we're

0:16:02.040 --> 0:16:02.800
<v Speaker 1>going for here.

0:16:03.040 --> 0:16:05.480
<v Speaker 2>Okay, so it would take longer, but I mean, if

0:16:05.520 --> 0:16:09.600
<v Speaker 2>you're doing like a generation ship on an interstellar journey,

0:16:10.080 --> 0:16:12.320
<v Speaker 2>you know you're not gonna be alive when you get

0:16:12.360 --> 0:16:15.400
<v Speaker 2>to the final destination anyway, so why not add an

0:16:15.400 --> 0:16:17.240
<v Speaker 2>extra five years to your trip to speed it up

0:16:17.240 --> 0:16:19.360
<v Speaker 2>For the next few generations. So let's assume we decide

0:16:19.360 --> 0:16:21.960
<v Speaker 2>we're going to do this anyway, or are you going

0:16:22.040 --> 0:16:23.160
<v Speaker 2>to get killed by the speed.

0:16:24.560 --> 0:16:27.200
<v Speaker 1>Well, before we answer that, there's another wrinkle, which is

0:16:27.240 --> 0:16:29.680
<v Speaker 1>you're right if you're like aiming for Alpha Centauri and

0:16:29.720 --> 0:16:31.720
<v Speaker 1>you want to be redirected and you don't want to

0:16:31.720 --> 0:16:34.200
<v Speaker 1>spend all that fuel. This is not a terrible idea,

0:16:34.520 --> 0:16:36.440
<v Speaker 1>but it's going to be more effective the closer you

0:16:36.480 --> 0:16:38.800
<v Speaker 1>get to the planet, right, because then the more powerful

0:16:38.840 --> 0:16:42.040
<v Speaker 1>the gravity. However, the closer you get to Jupiter, the

0:16:42.080 --> 0:16:44.320
<v Speaker 1>more you have to word about the radiation of Jupiter, right,

0:16:44.400 --> 0:16:46.800
<v Speaker 1>So there's really a trade off there. But here's the

0:16:46.840 --> 0:16:49.960
<v Speaker 1>thing about the G forces. There aren't any You don't

0:16:50.000 --> 0:16:54.040
<v Speaker 1>feel any of these G forces. That's right, because gravity

0:16:54.200 --> 0:16:58.080
<v Speaker 1>is not a force. You feel g forces when you're

0:16:58.080 --> 0:17:00.760
<v Speaker 1>being accelerated. So for example, if you're on a roller

0:17:00.800 --> 0:17:02.920
<v Speaker 1>coaster and you reach the bottom of the roller coaster

0:17:02.960 --> 0:17:05.280
<v Speaker 1>and you start going up, you feel those G forces.

0:17:05.560 --> 0:17:07.720
<v Speaker 1>Or if you're in a car and you're turning really fast,

0:17:07.760 --> 0:17:10.040
<v Speaker 1>you feel those G forces. Or if you're in a

0:17:10.119 --> 0:17:13.240
<v Speaker 1>rocket and somebody burns the rocket really fast to get

0:17:13.280 --> 0:17:15.960
<v Speaker 1>you going off the planet, you feel those G forces.

0:17:16.440 --> 0:17:19.439
<v Speaker 1>When you are falling just under gravity, you feel no

0:17:19.560 --> 0:17:22.880
<v Speaker 1>G forces. So for example, you jump out of an airplane,

0:17:23.040 --> 0:17:26.480
<v Speaker 1>you don't feel any G forces. Right, you're in freefall.

0:17:27.160 --> 0:17:29.919
<v Speaker 1>You only feel G forces when there's acceleration, and you

0:17:29.960 --> 0:17:33.679
<v Speaker 1>only feel acceleration when you're fighting gravity. If you just

0:17:34.320 --> 0:17:36.840
<v Speaker 1>chill with gravity, man, and go with the flow of

0:17:36.880 --> 0:17:39.600
<v Speaker 1>the universe, you feel no G forces.

0:17:39.840 --> 0:17:42.240
<v Speaker 2>Okay, well, so what if what if you're on this

0:17:42.359 --> 0:17:45.040
<v Speaker 2>interstellar ship. You want to get the Jupiter speed up,

0:17:45.520 --> 0:17:49.040
<v Speaker 2>and the folks who major interstellarship planned ahead for the

0:17:49.080 --> 0:17:51.680
<v Speaker 2>problem that low gravity is bad for human bodies. And

0:17:51.720 --> 0:17:56.000
<v Speaker 2>now you are spinning, so you have artificial gravity in

0:17:56.040 --> 0:17:59.600
<v Speaker 2>your habitat to help with things like reproduction. Now where

0:17:59.640 --> 0:18:02.560
<v Speaker 2>you feel on the G forces with the artificial gravity.

0:18:02.359 --> 0:18:06.400
<v Speaker 1>You feel the artificial gravity absolutely, because that's not gravity, right,

0:18:06.760 --> 0:18:09.119
<v Speaker 1>that's the force from the structure of the ship holding

0:18:09.119 --> 0:18:11.520
<v Speaker 1>itself together. The same with like on the surface of

0:18:11.560 --> 0:18:13.920
<v Speaker 1>the Earth, you feel what we call gravity, but it's

0:18:13.920 --> 0:18:17.520
<v Speaker 1>really the Earth pushing you up against the natural inclination.

0:18:17.680 --> 0:18:20.480
<v Speaker 1>You have to fall towards the center of the curvature.

0:18:20.760 --> 0:18:23.040
<v Speaker 1>So yes, you feel the G forces from the spinning

0:18:23.400 --> 0:18:27.840
<v Speaker 1>that's real because it's not gravity. But falling into Jupiter's

0:18:27.840 --> 0:18:29.800
<v Speaker 1>gravitational field doesn't change that at all.

0:18:30.040 --> 0:18:30.200
<v Speaker 5>Yeah.

0:18:30.240 --> 0:18:32.200
<v Speaker 2>Okay, so sorry, So I knew that you would feel

0:18:32.280 --> 0:18:34.520
<v Speaker 2>the artificial gravity, But what I meant is when you're

0:18:34.560 --> 0:18:38.080
<v Speaker 2>feeling artificial gravity and then you accelerate, Yeah, do you

0:18:38.280 --> 0:18:41.639
<v Speaker 2>feel that acceleration more strongly when you're under artificial gravity

0:18:41.680 --> 0:18:42.280
<v Speaker 2>relative to No?

0:18:42.840 --> 0:18:44.720
<v Speaker 3>Okay, no, no, you're doing cool.

0:18:44.800 --> 0:18:47.439
<v Speaker 1>Yeah, so that's sort of awesome because you know, you

0:18:47.480 --> 0:18:49.639
<v Speaker 1>don't feel gravity at all, even though it's having an

0:18:49.640 --> 0:18:52.679
<v Speaker 1>impact on you, even though you are accelerating, you're changing

0:18:52.720 --> 0:18:55.800
<v Speaker 1>your vector from the point of view of somebody distant. Right.

0:18:55.920 --> 0:18:59.320
<v Speaker 1>This is the thing about gr is that it's very confusing.

0:18:59.320 --> 0:19:01.880
<v Speaker 1>It depends on who who watching from your point of view,

0:19:01.960 --> 0:19:05.679
<v Speaker 1>you never feel acceleration due to gravity. Somebody else looking

0:19:05.720 --> 0:19:08.520
<v Speaker 1>from far away, who doesn't see the curvature. They're like, well,

0:19:08.560 --> 0:19:11.720
<v Speaker 1>according to my coordinates, your velocity is changing and therefore

0:19:11.760 --> 0:19:15.199
<v Speaker 1>you're having acceleration. And that's cool. Gr Lets everybody have

0:19:15.320 --> 0:19:19.040
<v Speaker 1>their own calculation. But what do you feel is what's important. Right,

0:19:19.240 --> 0:19:21.280
<v Speaker 1>You're not going to be torn apart, your stomach's not

0:19:21.280 --> 0:19:22.960
<v Speaker 1>going to be shredded. Your organs are not going to

0:19:23.000 --> 0:19:25.879
<v Speaker 1>be squished. Feel free to dive closed to Jupiter in

0:19:25.920 --> 0:19:28.800
<v Speaker 1>your arcship on your way to Alpha Centauri. You have

0:19:28.840 --> 0:19:30.760
<v Speaker 1>to worry about the radiation, but you don't have to

0:19:30.760 --> 0:19:31.920
<v Speaker 1>worry about the g forces.

0:19:32.080 --> 0:19:34.480
<v Speaker 2>And because I have a pod in physics, I know

0:19:34.560 --> 0:19:36.840
<v Speaker 2>that GR stands for general relativity.

0:19:37.160 --> 0:19:43.640
<v Speaker 1>Yes, absolutely, joh relativity one of the most fascinating, beautiful

0:19:43.680 --> 0:19:46.679
<v Speaker 1>and I think widely misunderstood theories, mostly because of that

0:19:46.880 --> 0:19:50.280
<v Speaker 1>dang rubber sheet bowling ball analogy out there which confuses everybody.

0:19:50.480 --> 0:19:53.600
<v Speaker 2>Yeah, but we're here to clear up misconceptions, all right,

0:19:53.640 --> 0:19:56.919
<v Speaker 2>So let's find out if Rob wants to use a

0:19:56.960 --> 0:20:01.080
<v Speaker 2>gravitational slingshot for his journey to interest that I've decided

0:20:01.119 --> 0:20:01.720
<v Speaker 2>he's going on.

0:20:03.520 --> 0:20:06.399
<v Speaker 4>Hi, Daniel and Kelly, your explanations normally make sense, but

0:20:06.480 --> 0:20:08.440
<v Speaker 4>offered a great way to look at the scenario from

0:20:08.520 --> 0:20:11.200
<v Speaker 4>multiple interesting, different perspectives. Thanks again.

0:20:31.000 --> 0:20:34.200
<v Speaker 1>Okay, we're back and we're answering questions from listeners today.

0:20:34.200 --> 0:20:37.520
<v Speaker 1>And the next question is about major animals.

0:20:38.080 --> 0:20:41.159
<v Speaker 2>Major animals, Well, I've never heard them referred to as

0:20:41.240 --> 0:20:46.240
<v Speaker 2>major before majorly awesome, So I have never been to Spain,

0:20:47.119 --> 0:20:49.040
<v Speaker 2>how would you pronounce this name, Daniel?

0:20:49.080 --> 0:20:50.280
<v Speaker 3>Do you know Adamar?

0:20:50.600 --> 0:20:52.280
<v Speaker 1>I've never heard this name before, but it looks to

0:20:52.320 --> 0:20:53.080
<v Speaker 1>me like Adamar.

0:20:53.200 --> 0:20:56.760
<v Speaker 2>Yeah, all right, anyway, fantastic name, and so adam ar

0:20:56.840 --> 0:20:57.359
<v Speaker 2>from Spain.

0:20:57.760 --> 0:20:58.800
<v Speaker 3>Let's hear your question.

0:20:59.080 --> 0:21:01.320
<v Speaker 6>Hello, Danny and Kelly. My name is Adema and I'm

0:21:01.320 --> 0:21:04.679
<v Speaker 6>asking this question from Spain. I recently learned that elephant

0:21:04.720 --> 0:21:08.000
<v Speaker 6>seemed to identify different human languages and react differently depending

0:21:08.040 --> 0:21:10.080
<v Speaker 6>on what they hear, thus being able to know if

0:21:10.119 --> 0:21:12.240
<v Speaker 6>a group of humans poses a threat to them based

0:21:12.280 --> 0:21:15.720
<v Speaker 6>on a language they speak Differently, Rainos seem to adopt

0:21:15.720 --> 0:21:19.639
<v Speaker 6>a more increasive behavior whenever the spots kincas. Some suggesting

0:21:19.680 --> 0:21:22.239
<v Speaker 6>that this could be a consequence of biological adaptation as

0:21:22.240 --> 0:21:24.680
<v Speaker 6>they evolve in contact with humans for many, many times,

0:21:24.800 --> 0:21:27.399
<v Speaker 6>in fact, since the beginning of the Haminites. What is

0:21:27.480 --> 0:21:29.520
<v Speaker 6>most intriguing is that this could be the reason why

0:21:29.520 --> 0:21:32.520
<v Speaker 6>great animals don't exist in any continent other than Africa.

0:21:32.680 --> 0:21:35.199
<v Speaker 6>As our arrival, there was much mosch suven and they

0:21:35.240 --> 0:21:37.320
<v Speaker 6>didn't have time to bolf an adapt to us before

0:21:37.320 --> 0:21:40.280
<v Speaker 6>we hunted them down to extinction. May Kelly give us

0:21:40.280 --> 0:21:43.119
<v Speaker 6>a dieper insight in this matter? Thank you for having me,

0:21:43.160 --> 0:21:45.960
<v Speaker 6>and congratulations for providing us with such an awesome podcast.

0:21:46.280 --> 0:21:49.000
<v Speaker 2>All right, So my opinion on the matter is pretty

0:21:49.080 --> 0:21:52.560
<v Speaker 2>much that Adamar was right right on the money. So

0:21:52.600 --> 0:21:55.159
<v Speaker 2>we're just going to go ahead and talk about the

0:21:55.200 --> 0:21:58.320
<v Speaker 2>science here because it's a really fascinating story and Adamore

0:21:58.359 --> 0:22:00.560
<v Speaker 2>seems to have a good handle on it. But I'm

0:22:00.560 --> 0:22:02.280
<v Speaker 2>just gonna go ahead and reiterate how cool all this

0:22:02.280 --> 0:22:02.720
<v Speaker 2>stuff is.

0:22:02.920 --> 0:22:05.520
<v Speaker 1>Yeah, Kelly, tell us the history. How much more awesome

0:22:05.640 --> 0:22:08.160
<v Speaker 1>was the Earth ten or fifty thousand years ago.

0:22:08.359 --> 0:22:09.560
<v Speaker 3>Before humans came along?

0:22:09.600 --> 0:22:13.200
<v Speaker 2>All right, So there were a lot more large mammals

0:22:13.200 --> 0:22:15.640
<v Speaker 2>on the planet, and by large we mean greater than

0:22:15.640 --> 0:22:16.840
<v Speaker 2>forty four kilograms.

0:22:17.080 --> 0:22:20.440
<v Speaker 1>Why forty four not forty five, not forty Who decided?

0:22:20.520 --> 0:22:23.200
<v Speaker 1>Was there some meeting the forty four kilogram threshold?

0:22:23.440 --> 0:22:26.080
<v Speaker 2>I don't know who decided on the forty four kilogram threshold.

0:22:26.119 --> 0:22:28.800
<v Speaker 2>No doubt it was arbitrary. No, somebody must have looked

0:22:28.800 --> 0:22:30.919
<v Speaker 2>at an animal and been like, you're too small.

0:22:32.960 --> 0:22:35.520
<v Speaker 3>How much do you weigh? You are now our threshold?

0:22:36.200 --> 0:22:39.120
<v Speaker 1>Oh, I didn't hurt that poor animal's feelings.

0:22:39.200 --> 0:22:39.680
<v Speaker 3>Well, we'll get it.

0:22:39.920 --> 0:22:41.960
<v Speaker 2>I mean, the good news if you're below the threshold.

0:22:41.960 --> 0:22:44.480
<v Speaker 2>It sounds like you were maybe less susceptible to extinction

0:22:45.000 --> 0:22:47.080
<v Speaker 2>caused by humans, So maybe you'd be happy if you

0:22:47.080 --> 0:22:48.680
<v Speaker 2>were under this arbitrary threshold.

0:22:48.800 --> 0:22:51.440
<v Speaker 1>So tell us about these megafauna that used to roam

0:22:51.520 --> 0:22:51.960
<v Speaker 1>the earth.

0:22:52.200 --> 0:22:55.520
<v Speaker 2>Okay, So this large megafauna includes things like you mentioned

0:22:55.600 --> 0:22:58.720
<v Speaker 2>at the beginning of the show, like lions that used

0:22:58.720 --> 0:23:02.280
<v Speaker 2>to be found much farther north. There were also giant

0:23:02.359 --> 0:23:06.119
<v Speaker 2>ground sloths. There were kangaroos that were much larger, and

0:23:06.160 --> 0:23:08.959
<v Speaker 2>there were mammoths. There were just lots of much larger

0:23:09.040 --> 0:23:13.400
<v Speaker 2>mammals that were roaming the earth. And somewhere between ten

0:23:13.440 --> 0:23:16.320
<v Speaker 2>to fifty thousand years ago, about two hundred of these

0:23:16.400 --> 0:23:18.919
<v Speaker 2>large mammal species went extinct.

0:23:19.160 --> 0:23:19.640
<v Speaker 1>Wow.

0:23:19.760 --> 0:23:23.840
<v Speaker 2>And this is called the quarternary megafauna extinction QM.

0:23:24.280 --> 0:23:26.960
<v Speaker 1>And is there a bigger trend here that like animals

0:23:26.960 --> 0:23:29.800
<v Speaker 1>get bigger and bigger, because like dinosaurs got really huge

0:23:30.240 --> 0:23:31.960
<v Speaker 1>and then you know, the biggest ones died out, and

0:23:31.960 --> 0:23:34.639
<v Speaker 1>then mammals come along and then they eventually got big.

0:23:35.040 --> 0:23:37.800
<v Speaker 1>Is this some sort of evolutionary trend that like, eventually

0:23:37.800 --> 0:23:40.400
<v Speaker 1>somebody finds the niche of like being too big to eat?

0:23:40.600 --> 0:23:42.800
<v Speaker 2>I mean, I'm sure a lot of things go into

0:23:43.359 --> 0:23:47.000
<v Speaker 2>optimal size for animals. Being big does make you too

0:23:47.080 --> 0:23:48.760
<v Speaker 2>big to eat, but you know, like so t rex

0:23:48.840 --> 0:23:52.239
<v Speaker 2>was a big predator, and you know, blue whales are

0:23:52.240 --> 0:23:54.800
<v Speaker 2>also big predators, but they're going after kraill, So it's

0:23:54.840 --> 0:23:56.359
<v Speaker 2>not they don't have to be big so that they

0:23:56.359 --> 0:23:59.359
<v Speaker 2>can be vicious and take downloaded animals. They're eating teeny

0:23:59.359 --> 0:24:02.720
<v Speaker 2>tiny little creatures called kraill, little crustaceans in the ocean,

0:24:03.440 --> 0:24:04.840
<v Speaker 2>and so, yeah, I'm sure a lot of things go

0:24:04.960 --> 0:24:07.600
<v Speaker 2>into being big, but it is a niche that sometimes

0:24:07.640 --> 0:24:11.000
<v Speaker 2>makes sense to fill. Yeah, about ten to fifty thousand

0:24:11.040 --> 0:24:13.240
<v Speaker 2>years ago, we lost a bunch of these species. And

0:24:13.440 --> 0:24:18.720
<v Speaker 2>the question is why, and you know, probably because it's biology,

0:24:18.840 --> 0:24:19.919
<v Speaker 2>the answer is it depends.

0:24:19.960 --> 0:24:21.359
<v Speaker 3>There's probably a lot of different factors.

0:24:21.400 --> 0:24:23.000
<v Speaker 2>It could have been that climate was changing at the

0:24:23.040 --> 0:24:25.840
<v Speaker 2>time as well, but there's pretty good evidence to suggest

0:24:25.880 --> 0:24:28.679
<v Speaker 2>that one of the major causes of this decline in

0:24:28.760 --> 0:24:31.760
<v Speaker 2>large mammals was the fact that humans were starting to

0:24:31.840 --> 0:24:32.760
<v Speaker 2>move into.

0:24:32.520 --> 0:24:36.680
<v Speaker 3>New areas, so lunch basically lunch. Yes, that's right.

0:24:36.840 --> 0:24:41.600
<v Speaker 2>So, for example, about fourteen of the sixteen large mammal

0:24:41.640 --> 0:24:46.160
<v Speaker 2>species that were present in Australia went extinct between about

0:24:46.200 --> 0:24:49.439
<v Speaker 2>thirty and fifty thousand years ago, and humans showed up

0:24:49.480 --> 0:24:52.840
<v Speaker 2>about forty to sixty thousand years ago, So the numbers

0:24:52.840 --> 0:24:55.760
<v Speaker 2>don't match up exactly, but some evidence that humans show

0:24:55.840 --> 0:25:00.359
<v Speaker 2>up and those species go extinct. In North America, humans

0:25:00.440 --> 0:25:04.800
<v Speaker 2>arrived around like twelve to twenty thousand years ago, and

0:25:05.080 --> 0:25:08.159
<v Speaker 2>eighty three percent of the large mammals in North America,

0:25:08.240 --> 0:25:10.960
<v Speaker 2>which was thirty four out of forty seven species, went

0:25:11.040 --> 0:25:14.280
<v Speaker 2>extinct somewhere between eleven to fifteen thousand years ago. So

0:25:14.359 --> 0:25:17.800
<v Speaker 2>we show up, eighty three percent of the large mammals disappear.

0:25:17.960 --> 0:25:20.240
<v Speaker 1>And I guess it's easy to draw the doged line

0:25:20.280 --> 0:25:22.600
<v Speaker 1>to say, like, well, humans probably killed them, or humans

0:25:22.600 --> 0:25:24.879
<v Speaker 1>maybe ate them or whatever. But it could also be

0:25:24.920 --> 0:25:28.359
<v Speaker 1>more complex, right, Humans arriving could change the ecosystem, and

0:25:28.440 --> 0:25:31.639
<v Speaker 1>these megafauna could be sensitive to like the web underneath

0:25:31.640 --> 0:25:33.880
<v Speaker 1>them that are changing. Maybe humans are eating something else

0:25:33.880 --> 0:25:36.720
<v Speaker 1>the megafauna were eating or something. It could just be

0:25:36.760 --> 0:25:38.040
<v Speaker 1>more complicated.

0:25:37.560 --> 0:25:40.399
<v Speaker 2>Right absolutely, Or maybe we brought some disease that jumped

0:25:40.440 --> 0:25:43.360
<v Speaker 2>from us to them, or we brought some other domesticated

0:25:43.400 --> 0:25:46.000
<v Speaker 2>animals along that killed them in some way, so yeah,

0:25:46.000 --> 0:25:48.399
<v Speaker 2>there's a lot of complicated It's not just necessarily that

0:25:48.480 --> 0:25:52.200
<v Speaker 2>we like ran after them with spears and we ate them, but.

0:25:52.160 --> 0:25:53.199
<v Speaker 1>We probably did a little of that too.

0:25:53.440 --> 0:25:54.520
<v Speaker 3>Yeah, no, I'm not sure.

0:25:54.520 --> 0:25:58.240
<v Speaker 2>There's some fossil evidence that we did some of that too. Yeah,

0:25:58.280 --> 0:26:01.480
<v Speaker 2>we needed to eat. But anyway, there is this correlational

0:26:01.520 --> 0:26:04.560
<v Speaker 2>evidence that when humans show up on a new continent

0:26:05.040 --> 0:26:08.600
<v Speaker 2>not that long after, a large percent of their large

0:26:08.600 --> 0:26:09.680
<v Speaker 2>mammals go extinct.

0:26:09.800 --> 0:26:11.959
<v Speaker 1>And I guess another thing we should consider is there

0:26:11.960 --> 0:26:15.359
<v Speaker 1>could be like confounding factors also, like something which caused

0:26:15.400 --> 0:26:18.080
<v Speaker 1>humans to move there and could also cause the extinction,

0:26:18.520 --> 0:26:21.360
<v Speaker 1>but which wouldn't put the blame on humanity really at all.

0:26:21.560 --> 0:26:22.160
<v Speaker 3>Yeah, that's right.

0:26:22.200 --> 0:26:25.240
<v Speaker 2>So if there were, for example, large climactic changes that

0:26:25.359 --> 0:26:28.000
<v Speaker 2>made some areas bad for humans, and they were migrating

0:26:28.320 --> 0:26:30.840
<v Speaker 2>in search of new food sources or something, right, it

0:26:30.880 --> 0:26:32.640
<v Speaker 2>could be that humans came at the same time as

0:26:32.640 --> 0:26:35.240
<v Speaker 2>the climate change. There have been people who have looked

0:26:35.240 --> 0:26:38.160
<v Speaker 2>into this, and I think that they conclude that humans

0:26:38.160 --> 0:26:40.680
<v Speaker 2>still probably played a role even after you control for

0:26:40.760 --> 0:26:42.960
<v Speaker 2>some other stuff that we know was happening at that time,

0:26:43.280 --> 0:26:46.760
<v Speaker 2>but it probably wasn't just humans, but it looks like mammals.

0:26:46.840 --> 0:26:47.600
<v Speaker 3>Large mammals in.

0:26:47.560 --> 0:26:51.359
<v Speaker 2>Particular were susceptible to death around this time, not just

0:26:51.400 --> 0:26:53.280
<v Speaker 2>because we were hunting them or whatever it was about

0:26:53.359 --> 0:26:55.879
<v Speaker 2>humans that caused them to die, but in particular, large

0:26:55.880 --> 0:26:59.199
<v Speaker 2>mammals tend to have They live a long time, but

0:26:59.480 --> 0:27:02.000
<v Speaker 2>it takes a long time for them to start making babies,

0:27:02.119 --> 0:27:04.359
<v Speaker 2>and when they do make babies, they don't make a

0:27:04.400 --> 0:27:06.960
<v Speaker 2>lot of them. You may remember our conversation about k

0:27:07.119 --> 0:27:10.840
<v Speaker 2>selected species that we had with Katie Golden. So large

0:27:10.840 --> 0:27:13.159
<v Speaker 2>mammals tend to not have a lot of babies to

0:27:13.320 --> 0:27:15.440
<v Speaker 2>begin with, so it's a little bit easier to kill

0:27:15.480 --> 0:27:18.000
<v Speaker 2>them off because they can't sort of bounce back as quickly.

0:27:18.119 --> 0:27:21.399
<v Speaker 1>Fascinating, and so the question really is like, why didn't

0:27:21.440 --> 0:27:23.800
<v Speaker 1>the same thing happen in Africa. It seems like Africa

0:27:23.880 --> 0:27:27.880
<v Speaker 1>has more megafauna than the other continents. Why is that?

0:27:28.200 --> 0:27:29.440
<v Speaker 3>Yeah, that is a great question.

0:27:29.520 --> 0:27:32.520
<v Speaker 2>So during the same period, only ten of the forty

0:27:32.560 --> 0:27:35.760
<v Speaker 2>eight large mammal species in Africa went extinct, and in

0:27:35.800 --> 0:27:38.560
<v Speaker 2>Eurasia they lost nine of twenty six species, so that's

0:27:38.560 --> 0:27:42.880
<v Speaker 2>a much lower percent. The current hypothesis is that humans

0:27:42.960 --> 0:27:44.440
<v Speaker 2>evolved in these areas.

0:27:44.760 --> 0:27:46.600
<v Speaker 3>So as our species.

0:27:46.200 --> 0:27:48.720
<v Speaker 2>Was picking up the skills for hunting and stuff like that,

0:27:49.240 --> 0:27:52.040
<v Speaker 2>we were evolving alongside of these species. So as we

0:27:52.080 --> 0:27:54.960
<v Speaker 2>got better, we didn't get like great at this overnight,

0:27:54.960 --> 0:27:57.560
<v Speaker 2>but as we got better, selection was sort of favoring

0:27:57.600 --> 0:28:02.560
<v Speaker 2>traits in, for example, elephants, to help them stay essentially

0:28:02.560 --> 0:28:05.520
<v Speaker 2>stay away from humans and keep themselves alive in the

0:28:05.520 --> 0:28:08.399
<v Speaker 2>face of this sort of growing super predator which we

0:28:08.400 --> 0:28:10.840
<v Speaker 2>would end up becoming. And so the idea here is

0:28:10.840 --> 0:28:15.040
<v Speaker 2>that Africa and Eurasia, those animals evolved with us, and

0:28:15.119 --> 0:28:17.359
<v Speaker 2>so they were just better able to escape us. But

0:28:17.400 --> 0:28:19.879
<v Speaker 2>then when we went to somewhere new like Australia and

0:28:19.880 --> 0:28:23.600
<v Speaker 2>North America, and these animals had never seen anything like us,

0:28:24.560 --> 0:28:26.360
<v Speaker 2>all of a sudden we show up with our spears

0:28:26.400 --> 0:28:30.080
<v Speaker 2>and they are just no match for the super predators

0:28:30.080 --> 0:28:31.440
<v Speaker 2>who just landed on their continent.

0:28:31.640 --> 0:28:35.240
<v Speaker 1>Wow. Fascinating. So it's actually good luck to evolve together

0:28:35.280 --> 0:28:37.280
<v Speaker 1>with humans, right, rather than just have them show up

0:28:37.280 --> 0:28:37.920
<v Speaker 1>at your doorstep.

0:28:38.200 --> 0:28:40.880
<v Speaker 2>You want humans to be bugging you for thousands of years,

0:28:40.960 --> 0:28:44.000
<v Speaker 2>not just showing up unannounced. When we show up unannounced,

0:28:44.040 --> 0:28:46.040
<v Speaker 2>we are particularly problematic guests.

0:28:46.160 --> 0:28:48.560
<v Speaker 1>And what about this other idea that Adam r raises

0:28:48.760 --> 0:28:53.000
<v Speaker 1>about how elephants can like understand human language and guess

0:28:53.040 --> 0:28:54.920
<v Speaker 1>our intentions. Is there anything to that.

0:28:55.000 --> 0:28:57.160
<v Speaker 2>I don't think Adam Or in particular was trying to

0:28:57.200 --> 0:29:01.440
<v Speaker 2>say that elephants can understand language. They sent a paper

0:29:01.480 --> 0:29:05.320
<v Speaker 2>from twenty fourteen by macomb at All in proceedings of

0:29:05.400 --> 0:29:08.520
<v Speaker 2>the National Academy of Sciences, and essentially what they did

0:29:08.560 --> 0:29:11.280
<v Speaker 2>here was they tried to figure out if elephants, just

0:29:11.360 --> 0:29:14.440
<v Speaker 2>from hearing an audio clip would respond in a way

0:29:14.440 --> 0:29:16.680
<v Speaker 2>that suggested that they knew that different kinds of people

0:29:16.720 --> 0:29:19.280
<v Speaker 2>differed in the risk that they posed to the elephants.

0:29:19.440 --> 0:29:19.880
<v Speaker 1>Wow.

0:29:20.040 --> 0:29:20.240
<v Speaker 3>Yeah.

0:29:20.280 --> 0:29:25.000
<v Speaker 2>For example, the Massi people are pastoralists, so their grazing

0:29:25.160 --> 0:29:28.960
<v Speaker 2>land and water holes are often areas that are also

0:29:29.040 --> 0:29:32.320
<v Speaker 2>used by elephants and are used by the livestock that

0:29:32.360 --> 0:29:35.560
<v Speaker 2>the Massi are sort of walking around the area, and

0:29:35.600 --> 0:29:38.360
<v Speaker 2>so they often come in conflict and sometimes the elephants

0:29:38.400 --> 0:29:42.120
<v Speaker 2>will kill Massi and the Massai need to essentially defend themselves.

0:29:42.800 --> 0:29:45.920
<v Speaker 2>On the other hand, the Kamba people are more agricultural

0:29:46.040 --> 0:29:48.600
<v Speaker 2>and they rarely have run ins with elephants, and when

0:29:48.640 --> 0:29:51.080
<v Speaker 2>they do have run ins, it's usually like a male

0:29:51.160 --> 0:29:54.880
<v Speaker 2>elephant who has sort of invaded their field, and so

0:29:55.080 --> 0:29:58.280
<v Speaker 2>the Kamba people are often leaving alone females and the

0:29:58.320 --> 0:30:03.040
<v Speaker 2>groups of females with their babies. And additionally, human females,

0:30:03.160 --> 0:30:07.120
<v Speaker 2>whether the Massi or Kamba, are unlikely to kill elephants,

0:30:07.160 --> 0:30:09.840
<v Speaker 2>and young boys are also unlikely to kill elephants. The

0:30:09.840 --> 0:30:12.680
<v Speaker 2>people who are most likely to kill elephants are adult men.

0:30:13.280 --> 0:30:16.640
<v Speaker 2>So they did this playback experiment where they had everybody

0:30:16.720 --> 0:30:19.840
<v Speaker 2>read the same sentence, and the sentence was look over there,

0:30:20.000 --> 0:30:22.600
<v Speaker 2>a group of elephants is coming, and they said it

0:30:22.680 --> 0:30:25.000
<v Speaker 2>in their own language, and then they look to see

0:30:25.040 --> 0:30:28.600
<v Speaker 2>what the elephants did. And when you played a Massi

0:30:28.680 --> 0:30:32.680
<v Speaker 2>man saying that sentence, the elephants would bunch together in

0:30:32.720 --> 0:30:35.400
<v Speaker 2>a defensive like huddle, and they would respond in a

0:30:35.400 --> 0:30:39.160
<v Speaker 2>way that suggested that they were experiencing fear because a

0:30:39.200 --> 0:30:40.120
<v Speaker 2>predator was around.

0:30:40.280 --> 0:30:40.680
<v Speaker 1>Wow.

0:30:40.920 --> 0:30:42.480
<v Speaker 2>Yeah, and they did less of that when they heard

0:30:42.480 --> 0:30:45.000
<v Speaker 2>the Kamba people. And remember, these are people that often

0:30:45.120 --> 0:30:47.200
<v Speaker 2>don't end up in positions where they need to defend

0:30:47.240 --> 0:30:51.680
<v Speaker 2>themselves in their livelihoods against elephants. The elephants also responded

0:30:51.680 --> 0:30:54.160
<v Speaker 2>more strongly to the sound of men than women, and

0:30:54.200 --> 0:30:57.480
<v Speaker 2>more strongly to the sound of men massi relative to

0:30:57.640 --> 0:31:00.640
<v Speaker 2>boy massi. So the elephants, you seem to have a

0:31:00.640 --> 0:31:03.200
<v Speaker 2>pretty good sense that, like, humans are risky, but some

0:31:03.320 --> 0:31:06.040
<v Speaker 2>kinds of humans are more risky than others, and so

0:31:06.080 --> 0:31:08.640
<v Speaker 2>they seem to have this like nuanced ability to tell

0:31:08.760 --> 0:31:10.360
<v Speaker 2>human risk and respond accordingly.

0:31:10.560 --> 0:31:12.600
<v Speaker 1>I told you the elephants are listening. They got those

0:31:12.600 --> 0:31:15.160
<v Speaker 1>big ears, and they can tell when you're talking about them.

0:31:15.480 --> 0:31:18.800
<v Speaker 2>That's right, that's right, and they never forget and so

0:31:18.800 --> 0:31:21.320
<v Speaker 2>so you got to be extra careful. But it's worth

0:31:21.360 --> 0:31:25.040
<v Speaker 2>noting that many animals respond to humans as though we

0:31:25.080 --> 0:31:28.400
<v Speaker 2>are risky. And that's even in North America. In Europe,

0:31:28.440 --> 0:31:31.880
<v Speaker 2>they've done playback experiments with badgers that freak out if

0:31:31.920 --> 0:31:35.040
<v Speaker 2>you play sounds at water holes. In Africa, just about

0:31:35.080 --> 0:31:38.080
<v Speaker 2>every species that hears the sound of a human, they'll

0:31:38.120 --> 0:31:40.120
<v Speaker 2>respond more strongly to the sound of a human than

0:31:40.120 --> 0:31:41.480
<v Speaker 2>the sound of a lion.

0:31:41.680 --> 0:31:41.880
<v Speaker 1>Wow.

0:31:42.000 --> 0:31:44.400
<v Speaker 2>So in general, just about any continent you go to,

0:31:44.760 --> 0:31:48.280
<v Speaker 2>the animals know humans often mean trouble. We should we

0:31:48.320 --> 0:31:51.800
<v Speaker 2>should leave town or get defensive. We're going to cause

0:31:51.840 --> 0:31:54.160
<v Speaker 2>some trouble. So this is sort of an unrelated topic

0:31:54.640 --> 0:31:57.760
<v Speaker 2>than the extinction of animals. This is more like what

0:31:57.840 --> 0:32:00.720
<v Speaker 2>are animals doing in this day and age to respond

0:32:00.720 --> 0:32:02.800
<v Speaker 2>to humans? And maybe elephants were doing this back in

0:32:02.840 --> 0:32:04.840
<v Speaker 2>the past and that's what saved them from getting killed

0:32:04.840 --> 0:32:07.560
<v Speaker 2>by us. They just kind of gave us space. But

0:32:07.680 --> 0:32:11.640
<v Speaker 2>in general, humans can be devastating to wildlife.

0:32:12.480 --> 0:32:15.120
<v Speaker 1>Well, let's say some nice things about humans to balance

0:32:15.120 --> 0:32:17.240
<v Speaker 1>it out. You know, I think it's incredible that we

0:32:17.280 --> 0:32:20.560
<v Speaker 1>can unravel these stories. Recently, Hazel made this comment. She

0:32:20.640 --> 0:32:23.360
<v Speaker 1>was like, all sciences basically stuff happened and we figured

0:32:23.360 --> 0:32:25.840
<v Speaker 1>out why. And I was like, you know, that's a

0:32:25.880 --> 0:32:29.320
<v Speaker 1>pretty good point, Hazel. And it touches on this incredible

0:32:29.360 --> 0:32:31.360
<v Speaker 1>thing that we do in science, which is like gather

0:32:31.520 --> 0:32:35.560
<v Speaker 1>these clues that are just like randomly accidentally left imprinted

0:32:35.680 --> 0:32:38.200
<v Speaker 1>on the world to figure out what happened, right, to

0:32:38.280 --> 0:32:41.720
<v Speaker 1>unravel this incredible story you're telling over tens of thousands

0:32:41.720 --> 0:32:44.480
<v Speaker 1>of years about these huge animals that no longer exist

0:32:44.600 --> 0:32:48.280
<v Speaker 1>and why and a complicated interplay between species. It's incredible

0:32:48.320 --> 0:32:50.240
<v Speaker 1>to me that we can unravel these stories, that we

0:32:50.320 --> 0:32:53.560
<v Speaker 1>can pull them out, sometimes literally out of the ground,

0:32:54.040 --> 0:32:56.320
<v Speaker 1>to learn the deep history of our universe.

0:32:56.480 --> 0:32:59.640
<v Speaker 2>Yeah, and you are always a more optimistic and uplifting

0:32:59.680 --> 0:33:00.640
<v Speaker 2>person than I am.

0:33:00.800 --> 0:33:02.880
<v Speaker 3>And so that that's beautiful.

0:33:02.440 --> 0:33:05.480
<v Speaker 2>And I'll attempt to follow in your footsteps by noting

0:33:05.880 --> 0:33:08.959
<v Speaker 2>that by understanding the damage we've done in the past,

0:33:09.360 --> 0:33:12.400
<v Speaker 2>you know, we can try to ameliorate the damage that

0:33:12.440 --> 0:33:14.560
<v Speaker 2>we might be doing now or the damage we might

0:33:14.640 --> 0:33:16.560
<v Speaker 2>be doing in the future. And so, you know, the

0:33:16.600 --> 0:33:20.560
<v Speaker 2>conservation movement has grown in you know, the last couple decades,

0:33:20.560 --> 0:33:23.280
<v Speaker 2>and we're getting better at caring about this stuff and

0:33:23.360 --> 0:33:26.560
<v Speaker 2>trying to at least slow the decline of some of

0:33:26.560 --> 0:33:29.520
<v Speaker 2>these species and in other cases turn around the decline

0:33:29.520 --> 0:33:32.760
<v Speaker 2>of species. So you know, if we can recognize our

0:33:32.800 --> 0:33:35.160
<v Speaker 2>past mistakes, we can hopefully use that information to do

0:33:35.240 --> 0:33:36.080
<v Speaker 2>better in the future.

0:33:36.520 --> 0:33:39.520
<v Speaker 1>Well, can I say something controversial? Do you think that

0:33:39.600 --> 0:33:43.680
<v Speaker 1>an individual species on its own has like inherent value?

0:33:43.760 --> 0:33:46.760
<v Speaker 1>Like should we be conserving every species or should we

0:33:46.760 --> 0:33:49.960
<v Speaker 1>take a bigger, broader view and say, Look, diversity is

0:33:50.000 --> 0:33:52.960
<v Speaker 1>important and that means that new species should be evolving

0:33:53.000 --> 0:33:55.720
<v Speaker 1>and sometimes species disappear, it's just part of the process.

0:33:56.240 --> 0:33:58.720
<v Speaker 1>Should we be trying to hold onto every individual species

0:33:58.800 --> 0:34:01.560
<v Speaker 1>or should we be maintaining diversity sort of in a

0:34:01.640 --> 0:34:02.280
<v Speaker 1>larger sense?

0:34:03.000 --> 0:34:06.880
<v Speaker 3>Wow, all right, So that question deserves like a whole episode.

0:34:06.880 --> 0:34:11.000
<v Speaker 2>But the short answer is, so there's a background extinction rate,

0:34:11.120 --> 0:34:16.000
<v Speaker 2>So you shouldn't necessarily lose sleep if a species goes extinct,

0:34:16.120 --> 0:34:17.839
<v Speaker 2>because that was going to happen whether humans were here

0:34:17.920 --> 0:34:20.720
<v Speaker 2>or not. But I believe the extinction rate is something

0:34:20.840 --> 0:34:24.200
<v Speaker 2>like it's at least ten times higher than we would

0:34:24.239 --> 0:34:26.839
<v Speaker 2>expect it to be based on background levels, So we

0:34:26.880 --> 0:34:31.160
<v Speaker 2>are really speeding things up for any particular species. I mean,

0:34:31.200 --> 0:34:34.480
<v Speaker 2>there are some species that play less important roles in ecosystems,

0:34:34.560 --> 0:34:36.960
<v Speaker 2>losing them would have less of an impact, but that's

0:34:37.000 --> 0:34:41.120
<v Speaker 2>still like a unique product of millions of years of

0:34:41.160 --> 0:34:45.280
<v Speaker 2>evolution that is beautiful and well adapted to its environment

0:34:45.320 --> 0:34:48.680
<v Speaker 2>and is being wiped out, you know, because of us,

0:34:48.840 --> 0:34:51.960
<v Speaker 2>And that to me does feel catastrophic and really sad.

0:34:52.200 --> 0:34:53.799
<v Speaker 2>And you know, I feel like you have to be

0:34:53.840 --> 0:34:57.040
<v Speaker 2>able to accept nuance in these conversations and weigh pros

0:34:57.080 --> 0:34:59.160
<v Speaker 2>and cons and stuff like that, but you know, I

0:34:59.440 --> 0:35:02.200
<v Speaker 2>do feel like time we lose a species, it is sad,

0:35:02.280 --> 0:35:04.120
<v Speaker 2>even if it's just a beetle that was present in

0:35:04.160 --> 0:35:05.160
<v Speaker 2>only one place.

0:35:05.000 --> 0:35:08.440
<v Speaker 1>Or something, well, it is an incredible output of evolution,

0:35:08.600 --> 0:35:13.160
<v Speaker 1>you know, it's like effectively billions of years of biological computation,

0:35:13.920 --> 0:35:16.680
<v Speaker 1>you know, to design this creator that can do something

0:35:16.760 --> 0:35:20.480
<v Speaker 1>amazing or has incredible chemicals in it. Anyway, stay tuned,

0:35:20.520 --> 0:35:23.520
<v Speaker 1>everybody for the upcoming episode where Daniel argues that extinction

0:35:23.680 --> 0:35:25.759
<v Speaker 1>is good. Actually, what.

0:35:27.320 --> 0:35:31.080
<v Speaker 2>Like all the extinction or just like I mean, this

0:35:31.160 --> 0:35:35.320
<v Speaker 2>might be the last episode of Extraordinary Universe.

0:35:36.840 --> 0:35:39.160
<v Speaker 1>All right, well we'll dig into that for another episode.

0:35:39.200 --> 0:35:42.240
<v Speaker 1>In the meantime, let's hear from Adamar about whether Kelly

0:35:42.320 --> 0:35:43.400
<v Speaker 1>answered their question.

0:35:43.800 --> 0:35:46.719
<v Speaker 6>Hello, young guys, and thank you for your response. It

0:35:46.800 --> 0:35:50.480
<v Speaker 6>makes me glad to think that possibly we're not the

0:35:50.600 --> 0:35:55.040
<v Speaker 6>only reason that those animals one extinct, And Kelly's context

0:35:55.160 --> 0:35:57.960
<v Speaker 6>really makes me think in a why that spectrum, like,

0:35:58.200 --> 0:36:01.640
<v Speaker 6>for example, what if it was the disease, what if

0:36:01.680 --> 0:36:05.000
<v Speaker 6>it was a glaciation the same we were running away from,

0:36:05.440 --> 0:36:09.400
<v Speaker 6>or maybe it wasn't other super predator anyway, who knows?

0:36:09.760 --> 0:36:32.080
<v Speaker 6>Thank you and keep up the Wool's work. All right.

0:36:32.160 --> 0:36:34.880
<v Speaker 2>I'm still trying to decide if I can forgive Daniel

0:36:34.920 --> 0:36:38.520
<v Speaker 2>for hinting that extinction caused by humans isn't always bad.

0:36:38.920 --> 0:36:41.160
<v Speaker 2>But you know what, I'm going to distract myself with

0:36:41.239 --> 0:36:43.280
<v Speaker 2>this insightful question from a listener.

0:36:43.440 --> 0:36:46.040
<v Speaker 5>Hey, Daniel and Kelly, really enjoying the podcast. Thank you.

0:36:46.280 --> 0:36:48.600
<v Speaker 5>I have a question for you, and it's about black holes.

0:36:48.640 --> 0:36:52.120
<v Speaker 5>Of course, black holes are usually described as unslakable consumers

0:36:52.120 --> 0:36:53.920
<v Speaker 5>of all matter and energy, but I know in some

0:36:54.000 --> 0:36:56.400
<v Speaker 5>cases the rate of consumption is limited by the energy

0:36:56.440 --> 0:36:59.960
<v Speaker 5>pressure of that consumption process, pushing back on the gravitation

0:37:00.200 --> 0:37:03.000
<v Speaker 5>pull and starving it of additional fuel. I would love

0:37:03.040 --> 0:37:04.880
<v Speaker 5>to hear more about what this might be like on

0:37:04.880 --> 0:37:07.800
<v Speaker 5>a more human scale, with a tiny primordial black hole

0:37:08.040 --> 0:37:10.680
<v Speaker 5>around the Earth generate a tiny accretion disc of matter

0:37:10.719 --> 0:37:13.280
<v Speaker 5>spinning around a light speed, generating the same kind of pressure,

0:37:13.320 --> 0:37:15.800
<v Speaker 5>and shooting out X ray lasers from the top and bottom.

0:37:16.160 --> 0:37:18.400
<v Speaker 5>How big or small would a black hole be to

0:37:18.440 --> 0:37:20.560
<v Speaker 5>have these sorts of effects. When we think of a

0:37:20.560 --> 0:37:23.359
<v Speaker 5>black hole interactive with normal human scale matter, what would

0:37:23.360 --> 0:37:25.400
<v Speaker 5>that look like? How long could the Earth survive with

0:37:25.400 --> 0:37:27.919
<v Speaker 5>a little black hole orbiting around inside of it? Really

0:37:27.920 --> 0:37:29.680
<v Speaker 5>looking forward to hearing more about this. Thank you.

0:37:30.120 --> 0:37:32.279
<v Speaker 1>Thank you David very much for that question. And I

0:37:32.320 --> 0:37:33.880
<v Speaker 1>hope that our answer is not going to help you

0:37:34.160 --> 0:37:37.120
<v Speaker 1>build a miniature black hole to embed into the Earth.

0:37:37.440 --> 0:37:39.320
<v Speaker 1>So We're just going to take it on good faith

0:37:39.360 --> 0:37:40.840
<v Speaker 1>and answer your question anyway.

0:37:41.440 --> 0:37:43.520
<v Speaker 3>That also sounds like a good topic for a sci

0:37:43.520 --> 0:37:44.120
<v Speaker 3>fi novel.

0:37:44.719 --> 0:37:46.840
<v Speaker 1>Let's talk about black holes and start with the basics,

0:37:46.880 --> 0:37:49.880
<v Speaker 1>because David's question involves a lot of sort of sophisticated

0:37:49.960 --> 0:37:54.360
<v Speaker 1>black hole science. Remember, black holes are regions of space

0:37:54.440 --> 0:37:57.200
<v Speaker 1>time where there's so much mass that there's so much

0:37:57.239 --> 0:38:01.200
<v Speaker 1>curvature that anything that falls beyond the event and eventually

0:38:01.239 --> 0:38:04.560
<v Speaker 1>reaches the center it can never escape. And something I

0:38:04.560 --> 0:38:06.640
<v Speaker 1>think a lot of people don't understand about black holes

0:38:06.680 --> 0:38:09.320
<v Speaker 1>is that the event horizon is not a physical surface.

0:38:09.760 --> 0:38:12.880
<v Speaker 1>It's just a designation. We make a dotted line, we draw,

0:38:13.400 --> 0:38:15.840
<v Speaker 1>and actually you never know where the event horizon is

0:38:15.880 --> 0:38:19.400
<v Speaker 1>at any moment. You can only tell in the infinite future. Essentially,

0:38:19.600 --> 0:38:22.160
<v Speaker 1>think about going to the infinite future and then asking

0:38:22.200 --> 0:38:26.000
<v Speaker 1>the question, in what regions of space did particles never escape?

0:38:26.200 --> 0:38:28.880
<v Speaker 1>Will now draw that to be the event horizon, and

0:38:28.960 --> 0:38:31.239
<v Speaker 1>so you can't ever really actually know. You can use

0:38:31.320 --> 0:38:34.120
<v Speaker 1>gr to predict at any moment, but the event horizon

0:38:34.200 --> 0:38:37.280
<v Speaker 1>is just like a categorization. We say, beyond this point,

0:38:37.560 --> 0:38:40.680
<v Speaker 1>nothing has escaped or can escape, and outside that point,

0:38:40.760 --> 0:38:44.200
<v Speaker 1>things can escape. But this is just gravity, right. Black

0:38:44.200 --> 0:38:47.480
<v Speaker 1>holes don't like suck with infinite power or anything. If

0:38:47.480 --> 0:38:49.400
<v Speaker 1>you replace the Sun with the black hole of the

0:38:49.440 --> 0:38:51.680
<v Speaker 1>same mass, we would feel it's gravity and the Earth

0:38:51.680 --> 0:38:54.160
<v Speaker 1>would continue to orbit. So it really is just a

0:38:54.200 --> 0:38:55.400
<v Speaker 1>gravitational object.

0:38:55.680 --> 0:38:57.960
<v Speaker 2>Okay, So at black hole the same size as our

0:38:58.040 --> 0:39:01.880
<v Speaker 2>Sun wouldn't pull on us anymore than our Sun because

0:39:01.880 --> 0:39:03.120
<v Speaker 2>they're similarly dense.

0:39:03.480 --> 0:39:05.160
<v Speaker 1>If it has the same mass and it's at the

0:39:05.160 --> 0:39:06.960
<v Speaker 1>same distance, it would have the same gravity.

0:39:06.960 --> 0:39:07.920
<v Speaker 3>Okay, yeah, right, I'm with you.

0:39:08.000 --> 0:39:10.200
<v Speaker 1>It wouldn't be as bright, and the Earth would be chilly,

0:39:10.520 --> 0:39:13.680
<v Speaker 1>and it would be bad, but not gravitationally, all right.

0:39:13.560 --> 0:39:14.520
<v Speaker 3>I don't want that to happen.

0:39:15.880 --> 0:39:18.799
<v Speaker 2>Does the event horizon always stay at the exact same

0:39:18.840 --> 0:39:21.800
<v Speaker 2>spot or does it shift over time if the black

0:39:21.800 --> 0:39:25.280
<v Speaker 2>hole like absorbs big things that make it bigger.

0:39:25.440 --> 0:39:28.279
<v Speaker 1>Absolutely, the event horizon depends on the mass of the

0:39:28.320 --> 0:39:31.440
<v Speaker 1>black hole and not just on the stuff inside the

0:39:31.480 --> 0:39:33.600
<v Speaker 1>event horizon. Right. This is why you shouldn't think about

0:39:33.600 --> 0:39:36.880
<v Speaker 1>the event horizon as some physical barrier. As you approach

0:39:36.880 --> 0:39:40.520
<v Speaker 1>a black hole, your gravitational energy contributes to the mass

0:39:40.560 --> 0:39:43.480
<v Speaker 1>of the black hole, So the black hole's vent horizon

0:39:43.520 --> 0:39:46.359
<v Speaker 1>actually grows out to meet you as you fall into

0:39:46.400 --> 0:39:48.840
<v Speaker 1>the black hole. So you approach the event horizon, the

0:39:48.880 --> 0:39:53.640
<v Speaker 1>event horizon approaches you. It's like a little gravitational hug. Oh.

0:39:53.880 --> 0:39:54.040
<v Speaker 6>Yeah.

0:39:54.080 --> 0:39:55.640
<v Speaker 2>We talked about what would happen if Zach was in

0:39:55.719 --> 0:39:57.719
<v Speaker 2>a black hole and if we threw him sandwiches, would

0:39:57.719 --> 0:39:58.360
<v Speaker 2>they ever get to it?

0:39:58.480 --> 0:40:00.919
<v Speaker 1>Exactly? And the reason you need to understand that black

0:40:00.920 --> 0:40:03.080
<v Speaker 1>holes are not infinitely powerful is to think about the

0:40:03.120 --> 0:40:06.320
<v Speaker 1>stuff that's orbiting them, because that's what David's question was about.

0:40:06.320 --> 0:40:09.040
<v Speaker 1>This accretion disc. When you think about the images of

0:40:09.080 --> 0:40:11.279
<v Speaker 1>black holes out there in space, they look like a

0:40:11.320 --> 0:40:14.719
<v Speaker 1>glowing donut with a black core, or you know the

0:40:14.840 --> 0:40:19.480
<v Speaker 1>visualization in Interstellar or whatever. They have these luminous discs

0:40:19.520 --> 0:40:21.680
<v Speaker 1>around them. What is that and why aren't they getting

0:40:21.719 --> 0:40:24.359
<v Speaker 1>sucked in? Well, they're not getting sucked into the black

0:40:24.400 --> 0:40:26.040
<v Speaker 1>hole for the same reason the Earth is not getting

0:40:26.080 --> 0:40:28.720
<v Speaker 1>sucked into the Sun. Right, there's a lot of gravity

0:40:28.719 --> 0:40:31.359
<v Speaker 1>from the Sun. Why aren't we just getting sucked into

0:40:31.360 --> 0:40:33.520
<v Speaker 1>the Sun? And the answer is we have velocity. There

0:40:33.560 --> 0:40:36.319
<v Speaker 1>are stable orbits around the Sun, and the same way

0:40:36.320 --> 0:40:38.439
<v Speaker 1>there are stable orbits around a black hole. Because it's

0:40:38.480 --> 0:40:42.160
<v Speaker 1>just a gravitational object. So if you approach a black hole,

0:40:42.239 --> 0:40:44.560
<v Speaker 1>as long as you were outside the event horizon, you

0:40:44.600 --> 0:40:48.120
<v Speaker 1>could orbit around it forever without falling in if you

0:40:48.160 --> 0:40:51.239
<v Speaker 1>were stable and crucially nothing bumped into you to knock

0:40:51.280 --> 0:40:52.080
<v Speaker 1>you out of your orbit.

0:40:52.239 --> 0:40:54.000
<v Speaker 3>That doesn't sound fun, I'll pass.

0:40:54.960 --> 0:40:57.080
<v Speaker 1>And that's the same story for the Earth right now.

0:40:57.200 --> 0:40:59.360
<v Speaker 1>The accretion disc is very different because it's not just

0:40:59.440 --> 0:41:01.880
<v Speaker 1>like one chunk of matter here when chunk of matter there,

0:41:02.080 --> 0:41:04.759
<v Speaker 1>it's just like a huge hot disk of gas and

0:41:04.880 --> 0:41:07.640
<v Speaker 1>dust that has a lot of internal friction. That's why

0:41:07.719 --> 0:41:10.560
<v Speaker 1>it's glowing. The tidal forces from the black hole are

0:41:10.560 --> 0:41:13.280
<v Speaker 1>massaging it and heating it up, and it's rubbing against

0:41:13.320 --> 0:41:16.239
<v Speaker 1>itself and so it's very hot and it's glowing. So

0:41:16.280 --> 0:41:18.920
<v Speaker 1>that's why we can see these black holes. These telescope

0:41:18.920 --> 0:41:22.000
<v Speaker 1>pictures of black holes. Really they're pictures of the hot

0:41:22.040 --> 0:41:25.279
<v Speaker 1>accretion disc around the black hole. So the accretion disc

0:41:25.320 --> 0:41:27.839
<v Speaker 1>is stuff that's orbiting the black hole, hasn't fallen in yet,

0:41:27.960 --> 0:41:32.240
<v Speaker 1>is going too fast, probably will fall in eventually because

0:41:32.280 --> 0:41:34.120
<v Speaker 1>there's a lot of friction there. So you can't just

0:41:34.160 --> 0:41:36.160
<v Speaker 1>like have a stable orbit. But it's sort of like

0:41:36.280 --> 0:41:38.520
<v Speaker 1>on deck to go in the black hole, but not

0:41:38.640 --> 0:41:39.280
<v Speaker 1>there yet.

0:41:39.440 --> 0:41:41.520
<v Speaker 2>And what is that made out of? Is that just

0:41:41.560 --> 0:41:45.120
<v Speaker 2>like the basic dust and junk that you find in space, it's.

0:41:44.960 --> 0:41:47.040
<v Speaker 1>Made out of whatever you've been feeding your black hole.

0:41:47.080 --> 0:41:50.640
<v Speaker 1>But yeah, the universe is mostly hydrogen, so it's always

0:41:50.640 --> 0:41:53.279
<v Speaker 1>a safe bet to say it's mostly hydrogen because that's

0:41:53.280 --> 0:41:55.920
<v Speaker 1>what the universe is. And so yeah, there's gas and

0:41:55.960 --> 0:41:59.480
<v Speaker 1>this dust and whatever, but mostly it's hydrogen there. And

0:41:59.600 --> 0:42:02.279
<v Speaker 1>here's the black hole starts to work against itself because

0:42:02.280 --> 0:42:05.239
<v Speaker 1>the accretion disc is so hot that it glows, right,

0:42:05.280 --> 0:42:07.480
<v Speaker 1>that's where we can see these things. So it emits

0:42:07.600 --> 0:42:11.440
<v Speaker 1>radiation pressure, so it pushes stuff away. Right. We talked

0:42:11.440 --> 0:42:13.800
<v Speaker 1>in a recent episode about how stars are a balance

0:42:13.800 --> 0:42:17.120
<v Speaker 1>between gravity and radiation pressure. The fusion at their hot

0:42:17.160 --> 0:42:20.000
<v Speaker 1>core is producing a lot of energy and that pushes

0:42:20.080 --> 0:42:22.399
<v Speaker 1>out on the star, and if the star is too big,

0:42:22.440 --> 0:42:24.480
<v Speaker 1>it can actually blow the star apart. That's why you

0:42:24.480 --> 0:42:27.360
<v Speaker 1>have like a maximum size of stars. Well, a similar

0:42:27.400 --> 0:42:30.359
<v Speaker 1>thing is happening here. The heat from the accretion disk

0:42:30.480 --> 0:42:34.360
<v Speaker 1>creates radiation which pushes other stuff away. So the hotter

0:42:34.440 --> 0:42:36.440
<v Speaker 1>the black hole, the bigger the black hole, the bigger

0:42:36.440 --> 0:42:40.680
<v Speaker 1>the accretion disk the more it slows down its ability

0:42:40.719 --> 0:42:45.160
<v Speaker 1>to eat stuff. So black holes cannot grow infinitely quickly.

0:42:45.400 --> 0:42:47.759
<v Speaker 1>There's no theoretical upper limit to the size of a

0:42:47.800 --> 0:42:51.560
<v Speaker 1>black hole, but because of this process, this radiation pressure,

0:42:51.680 --> 0:42:54.480
<v Speaker 1>there is an upper limit to how rapidly they can grow.

0:42:54.719 --> 0:42:56.640
<v Speaker 1>You put a black hole in a blob of stuff,

0:42:56.800 --> 0:43:00.840
<v Speaker 1>it can't just like slurp everything out really quickly because

0:43:00.880 --> 0:43:02.560
<v Speaker 1>it's going to get hot and glow and push its

0:43:02.560 --> 0:43:03.920
<v Speaker 1>own food away from itself.

0:43:04.160 --> 0:43:07.440
<v Speaker 3>So what determines the size of the accretion disc.

0:43:07.760 --> 0:43:09.560
<v Speaker 1>It's just how much stuff was there around it. Like

0:43:09.600 --> 0:43:11.239
<v Speaker 1>if you put a black hole in deep space and

0:43:11.320 --> 0:43:13.600
<v Speaker 1>nothing is there, it have no accretion disc. It would

0:43:13.640 --> 0:43:15.640
<v Speaker 1>just be black. We could not see it except for

0:43:15.680 --> 0:43:18.239
<v Speaker 1>its gravitational effects. You drop in the middle of a

0:43:18.239 --> 0:43:20.400
<v Speaker 1>really big blob of stuff, it's going to get a

0:43:20.400 --> 0:43:23.640
<v Speaker 1>big accretion disc. So it just depends on what's around it.

0:43:24.320 --> 0:43:27.040
<v Speaker 1>And this is a really interesting puzzle in physics right

0:43:27.080 --> 0:43:30.400
<v Speaker 1>now because this limit on how quickly black holes can

0:43:30.440 --> 0:43:33.320
<v Speaker 1>grow is one of the reasons why we don't understand

0:43:33.440 --> 0:43:36.880
<v Speaker 1>super massive black holes. We see super massive black holes

0:43:36.920 --> 0:43:39.320
<v Speaker 1>in the early history of the universe, like a billion

0:43:39.440 --> 0:43:42.760
<v Speaker 1>years after the Big bang already we have black holes

0:43:42.760 --> 0:43:44.879
<v Speaker 1>with like billions of times the mass of the Sun.

0:43:45.440 --> 0:43:48.040
<v Speaker 1>But if you do the calculations the limit on the

0:43:48.080 --> 0:43:50.640
<v Speaker 1>speed of which black holes can grow, tell you that's impossible.

0:43:50.840 --> 0:43:52.960
<v Speaker 1>So how did they get so big? That's the big

0:43:53.040 --> 0:43:56.120
<v Speaker 1>question of super massive black holes, although we have some

0:43:56.400 --> 0:43:59.600
<v Speaker 1>interesting hints that like, if the accretion disc is asymmetric,

0:43:59.680 --> 0:44:03.080
<v Speaker 1>then can have what they call super Eddington accretion rates.

0:44:03.640 --> 0:44:07.240
<v Speaker 1>It's fascinating. But David's question is about tiny black holes,

0:44:07.239 --> 0:44:10.520
<v Speaker 1>and he's asking, can they also have accretion discs?

0:44:10.840 --> 0:44:13.320
<v Speaker 2>And you told me that it doesn't matter how big

0:44:13.360 --> 0:44:16.200
<v Speaker 2>a black hole is. What matters is the stuff that started.

0:44:16.239 --> 0:44:19.080
<v Speaker 2>So could a tiny black hole have a huge accretion disk?

0:44:20.440 --> 0:44:23.160
<v Speaker 1>So a tiny black hole can have accretion disc And

0:44:23.200 --> 0:44:25.560
<v Speaker 1>this Eddington limit of the rate of which black holes

0:44:25.600 --> 0:44:29.320
<v Speaker 1>can grow scales with mass, so the limit is smaller

0:44:29.360 --> 0:44:32.680
<v Speaker 1>with smaller mass. So there's like less radiation pressure from

0:44:32.719 --> 0:44:35.719
<v Speaker 1>a smaller mass black hole because it can't heat up

0:44:35.719 --> 0:44:38.520
<v Speaker 1>its accretion discs as much. But at a very small

0:44:38.520 --> 0:44:42.560
<v Speaker 1>black hole, something else happens. Right, black holes don't just

0:44:42.640 --> 0:44:45.719
<v Speaker 1>glow because of their accretion disc They are themselves not

0:44:46.080 --> 0:44:49.759
<v Speaker 1>totally black. We think they glow themselves with a little

0:44:49.800 --> 0:44:53.400
<v Speaker 1>bit of Hawking radiation. This is this bizarre radiation that

0:44:53.440 --> 0:44:56.080
<v Speaker 1>happens because you have an event horizon in quantum fields

0:44:56.480 --> 0:44:58.960
<v Speaker 1>and there's this hand wavy story out there about particles

0:44:58.960 --> 0:45:01.959
<v Speaker 1>and antiparticles or one falls into the event horizon. That's

0:45:02.040 --> 0:45:04.680
<v Speaker 1>just cartoons. It's not really the physics of what's happening.

0:45:05.080 --> 0:45:07.600
<v Speaker 1>But we do think that Hawking radiation might be real.

0:45:07.880 --> 0:45:10.680
<v Speaker 1>And the crucial thing about it is that it's bigger

0:45:10.719 --> 0:45:14.600
<v Speaker 1>for smaller black holes. Really big black holes almost no

0:45:14.680 --> 0:45:19.560
<v Speaker 1>Hawking radiation. Smaller black holes dramatic Hawking radiation. So the

0:45:19.600 --> 0:45:22.760
<v Speaker 1>smaller the black hole gets, the bigger the Hawking radiation.

0:45:22.920 --> 0:45:25.520
<v Speaker 1>So this is actually going to be more radiation pressure

0:45:25.880 --> 0:45:28.359
<v Speaker 1>than the accretion disc. For a small enough black hole,

0:45:28.680 --> 0:45:32.279
<v Speaker 1>the Hawking radiation will be brighter than the glow from

0:45:32.320 --> 0:45:33.160
<v Speaker 1>the accretion disk.

0:45:33.480 --> 0:45:35.440
<v Speaker 3>Okay, so I'm picturing it now.

0:45:35.440 --> 0:45:37.880
<v Speaker 2>There's a black hole in the middle, there's an accretion

0:45:38.000 --> 0:45:41.880
<v Speaker 2>disc around it, and then Hawking radiation extends even beyond that,

0:45:42.440 --> 0:45:44.600
<v Speaker 2>and if you were looking, could do We have a

0:45:44.680 --> 0:45:47.840
<v Speaker 2>kind of telescope that could distinguish those three objects.

0:45:48.160 --> 0:45:50.880
<v Speaker 1>We have a telescope that can see black holes, and

0:45:50.960 --> 0:45:53.360
<v Speaker 1>we've only been able to see super massive black holes

0:45:53.920 --> 0:45:57.640
<v Speaker 1>and so those have essentially no Hawking radiation or unmeasurable amounts,

0:45:57.640 --> 0:46:00.319
<v Speaker 1>so we've never seen Hawking radiation. But if you had

0:46:00.360 --> 0:46:02.759
<v Speaker 1>a small enough black hole and it was nearby, it

0:46:02.800 --> 0:46:05.839
<v Speaker 1>would be very bright in Hawking radiation. So it did

0:46:05.840 --> 0:46:07.920
<v Speaker 1>the calculation and if you had a black hole with

0:46:08.000 --> 0:46:11.200
<v Speaker 1>like forty billion kilograms, which is about the mass of

0:46:11.200 --> 0:46:13.799
<v Speaker 1>the Hoover Dam, then the glow from the accretion disc

0:46:13.840 --> 0:46:16.680
<v Speaker 1>would be about as bright as the glow from Hawking radiation,

0:46:17.200 --> 0:46:20.000
<v Speaker 1>so like pretty bright. But this is tiny, you know,

0:46:20.040 --> 0:46:22.239
<v Speaker 1>this is like a tiny fraction of the mass of

0:46:22.239 --> 0:46:24.720
<v Speaker 1>the Earth. Even so this is really a very small

0:46:24.760 --> 0:46:27.600
<v Speaker 1>black hole. Like the gravity from the Hoover Dam is

0:46:27.680 --> 0:46:30.200
<v Speaker 1>not very powerful. Remember we had that episode about like

0:46:30.239 --> 0:46:33.560
<v Speaker 1>measuring gravity and like the Scottish guys climbing around that mountain,

0:46:33.920 --> 0:46:35.960
<v Speaker 1>that was a much bigger effect because that's a much

0:46:35.960 --> 0:46:38.600
<v Speaker 1>bigger mountain and still very hard to measure. Gravity is

0:46:38.600 --> 0:46:40.920
<v Speaker 1>super weak, So a black hole with the mass of

0:46:40.960 --> 0:46:43.759
<v Speaker 1>the Hoover Dam would not be very powerful, but it

0:46:43.800 --> 0:46:47.280
<v Speaker 1>would be as bright as it's accretion disk. So yes, David,

0:46:47.400 --> 0:46:51.080
<v Speaker 1>small black holes can have accretion disk. It depends on

0:46:51.120 --> 0:46:53.120
<v Speaker 1>what they've been eating. So if you have a tiny

0:46:53.120 --> 0:46:55.440
<v Speaker 1>black hole out in the middle of nowhere, no accretion disk.

0:46:55.719 --> 0:46:57.560
<v Speaker 1>You take a tiny black hole and you PLoP it

0:46:57.600 --> 0:47:00.680
<v Speaker 1>in a huge bed of plasma and hygigen and whatever.

0:47:01.000 --> 0:47:02.719
<v Speaker 1>It will get in accretion disk as well, but it

0:47:02.719 --> 0:47:05.200
<v Speaker 1>will also glow with its own hawking radiation.

0:47:05.440 --> 0:47:05.760
<v Speaker 3>Wow.

0:47:05.880 --> 0:47:07.600
<v Speaker 2>Okay, So then let's get to the last part of

0:47:07.680 --> 0:47:10.680
<v Speaker 2>David's question. If that if you put that black hole

0:47:10.719 --> 0:47:14.040
<v Speaker 2>in the center of the Earth, how long could Earth survive?

0:47:14.680 --> 0:47:17.200
<v Speaker 1>Yeah, this is a fascinating question as well, and I

0:47:17.239 --> 0:47:20.239
<v Speaker 1>thought it was a little unrealistic because we can't make

0:47:20.440 --> 0:47:23.359
<v Speaker 1>a black hole the size of the Hoover Dam. We

0:47:23.360 --> 0:47:25.279
<v Speaker 1>were unlikely to see one. So I thought, well, let's

0:47:25.320 --> 0:47:27.440
<v Speaker 1>take it another step. Let's say we did make a

0:47:27.440 --> 0:47:30.640
<v Speaker 1>black hole. Because, for example, at the Large Hadron Collider,

0:47:30.680 --> 0:47:32.799
<v Speaker 1>we're trying to make black holes all the time. We

0:47:32.840 --> 0:47:36.360
<v Speaker 1>smash protons together. Yeah, we smash protons together in the

0:47:36.440 --> 0:47:40.239
<v Speaker 1>hopes that occasionally they will create a tiny miniature black hole.

0:47:40.280 --> 0:47:43.480
<v Speaker 1>And remember, smaller black holes radiate faster than bigger black holes.

0:47:43.800 --> 0:47:45.960
<v Speaker 1>So we make a black hole to the large hadron collider.

0:47:46.000 --> 0:47:48.320
<v Speaker 1>It's going to have like ten to the minus twenty

0:47:48.440 --> 0:47:53.360
<v Speaker 1>four kilograms of mass. It'll almost instantly radiate itself away, hope.

0:47:53.400 --> 0:47:55.480
<v Speaker 1>But it would be awesome because then we'd learn something

0:47:55.520 --> 0:47:58.680
<v Speaker 1>about quantum gravity. It would be incredible. But if you

0:47:58.719 --> 0:48:01.319
<v Speaker 1>did take one of these things and somehow was able

0:48:01.360 --> 0:48:04.600
<v Speaker 1>to feed it before it radiated away, and you put

0:48:04.600 --> 0:48:06.160
<v Speaker 1>it in the center of the Earth, and then you

0:48:06.200 --> 0:48:08.040
<v Speaker 1>do a calculation of like how long would it take

0:48:08.080 --> 0:48:10.719
<v Speaker 1>to slurp up everything and consume the entire Earth? That

0:48:10.719 --> 0:48:13.359
<v Speaker 1>would take about ten thousand years, all right, So.

0:48:13.320 --> 0:48:16.440
<v Speaker 2>I wouldn't be around anymore. So fine, that's.

0:48:16.360 --> 0:48:18.080
<v Speaker 1>Right, that's all right, And you would have time to

0:48:18.160 --> 0:48:21.080
<v Speaker 1>jump on that arcship to Alpha Centauri, and we'd even

0:48:21.120 --> 0:48:23.080
<v Speaker 1>have time to design and build it, you know, because

0:48:23.120 --> 0:48:25.279
<v Speaker 1>ten thousand years is a good amount of time, even

0:48:25.320 --> 0:48:26.400
<v Speaker 1>for space projects.

0:48:26.480 --> 0:48:29.239
<v Speaker 2>But this ecologist feels like you probably shouldn't do anything

0:48:29.280 --> 0:48:30.920
<v Speaker 2>to destroy the Earth because there are a lot of

0:48:30.920 --> 0:48:34.680
<v Speaker 2>species that would get left behind, and every species is important.

0:48:34.760 --> 0:48:37.320
<v Speaker 3>Dan, Well, extinction's not okay.

0:48:40.000 --> 0:48:42.000
<v Speaker 1>Do you want to extinctify the mosquitos? How about that

0:48:42.080 --> 0:48:44.560
<v Speaker 1>wasp that bits you earlier? How's that thumb doing?

0:48:44.600 --> 0:48:47.520
<v Speaker 2>By the way, it's about thirty percent bigger than the

0:48:47.560 --> 0:48:50.120
<v Speaker 2>other thumb right now. But I still think that the

0:48:50.239 --> 0:48:54.200
<v Speaker 2>wasps they are important pollinators in some cases they control

0:48:54.880 --> 0:48:58.400
<v Speaker 2>like other insect populations, I think it deserves to stay.

0:48:58.760 --> 0:49:01.680
<v Speaker 2>I might get rid of mosquito. See I'm glad we

0:49:01.719 --> 0:49:04.680
<v Speaker 2>got rid of small pox there. I accept that there's

0:49:04.719 --> 0:49:08.080
<v Speaker 2>some nuance, but I'm your answer didn't sound like it

0:49:08.080 --> 0:49:09.520
<v Speaker 2>was gonna be very nuanced, Daniel.

0:49:10.440 --> 0:49:13.840
<v Speaker 1>I was just trying to be controversial success. Thank you

0:49:13.960 --> 0:49:16.640
<v Speaker 1>David for that question. Let us know if we answered it,

0:49:16.680 --> 0:49:18.760
<v Speaker 1>and follow up questions are always welcome.

0:49:19.120 --> 0:49:21.840
<v Speaker 7>Hi, Daniel and Kelly, thank you so much for that answer.

0:49:22.040 --> 0:49:24.520
<v Speaker 7>You did indeed answer the question and my only follow up.

0:49:25.040 --> 0:49:27.040
<v Speaker 7>If I were to waive my magic wond and create

0:49:27.080 --> 0:49:29.719
<v Speaker 7>a Hoover Dam sized black hole and situated somewhere that

0:49:29.719 --> 0:49:32.040
<v Speaker 7>I could watch it feed from ten or twenty meters away,

0:49:32.360 --> 0:49:34.640
<v Speaker 7>would I be able to enjoy the spectacle for the

0:49:34.760 --> 0:49:37.400
<v Speaker 7>three or four hundred microseconds it would take for the

0:49:37.440 --> 0:49:40.600
<v Speaker 7>stream of gamma rays and exotic particles to shred my spacesuit,

0:49:41.040 --> 0:49:43.120
<v Speaker 7>or would be a teency little firefly I could enjoy

0:49:43.200 --> 0:49:46.040
<v Speaker 7>until my oxygen ran out. Either way, I promise not

0:49:46.120 --> 0:49:49.480
<v Speaker 7>to destroy the Earth anytime soon. Thanks again, Thanks.

0:49:49.239 --> 0:49:51.320
<v Speaker 1>Everyone out there for joining us on this episode. We

0:49:51.480 --> 0:49:54.040
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