WEBVTT - How Ice Ages Work 0:00:00.120 --> 0:00:02.000 This episode of Stuff you Should Know is brought to 0:00:02.000 --> 0:00:04.760 you by square Space. Whether you need a landing page, 0:00:04.800 --> 0:00:08.119 a beautiful gallery, a professional blog, or an online store, 0:00:08.480 --> 0:00:11.200 it's all possible with a square space website. And right now, 0:00:11.240 --> 0:00:13.000 listeners to Stuff you Should Know can start a free 0:00:13.000 --> 0:00:16.000 trial today. Just go to squarespace dot com and enter 0:00:16.040 --> 0:00:18.600 the offer code s t U f F and you'll 0:00:18.640 --> 0:00:21.680 get ten percent off your first purchase. Squarespace set your 0:00:21.720 --> 0:00:26.360 website apart. Welcome to Stuff you Should Know from House 0:00:26.360 --> 0:00:36.000 Stuff Works dot com. Hey, I'm welcome to the podcast. 0:00:36.360 --> 0:00:40.360 I'm Josh Clark, and there's Charles W. Chuck Bryant and 0:00:40.600 --> 0:00:44.040 uh guests. Who's over there being quiet as a church mouse. 0:00:44.840 --> 0:00:50.120 The producer who may or may not exist, Jerry. People 0:00:50.159 --> 0:00:52.680 still think that. I think a few people do. Yeah, 0:00:53.520 --> 0:01:00.280 she's real, says you. She's real because I can always 0:01:00.280 --> 0:01:03.520 smell her me. So from here? Oh man? I um, 0:01:03.640 --> 0:01:06.760 so I like avocado a lot, right, So I like 0:01:06.800 --> 0:01:12.959 avocado a lot. Basically an avocado a day. Um, And 0:01:13.600 --> 0:01:15.839 normally I make guacamole. As you know, I make probably 0:01:15.840 --> 0:01:20.600 the best guacamole on the planet. Sometimes, okay, we'll have 0:01:20.640 --> 0:01:24.160 a guac off one day. Well, yeah, but it's personal taste, 0:01:24.160 --> 0:01:27.880 you know, you know that whole thing. Remember, no taste 0:01:27.920 --> 0:01:35.080 is absolute. Um. So it's sometimes it's just too much 0:01:35.120 --> 0:01:40.480 to make guac sure, right, that's where avocado toast comes in. Yeah, 0:01:40.800 --> 0:01:43.840 it's so easy, but and it's totally different too. So 0:01:43.880 --> 0:01:45.480 if you start to get sick of guacamole, you like, 0:01:45.560 --> 0:01:48.960 I'll have some avocado toast. Anyway. The upshot is is 0:01:49.000 --> 0:01:53.360 I recently took antibiotics, which are disgusting poison, but just 0:01:53.560 --> 0:01:55.520 had to have them this time because my body would 0:01:55.560 --> 0:02:00.280 not get rid of whatever had um. And so I've 0:02:00.320 --> 0:02:03.080 been like repopulating my gut flora with fermented stuff like 0:02:03.160 --> 0:02:07.559 mis Took some miso, put it in some avocado, whipped 0:02:07.560 --> 0:02:09.640 it up, spread it on some toasts. It was great. 0:02:10.840 --> 0:02:16.400 And avocado, being a fibrous vegetable, should be a prebiotic. 0:02:16.639 --> 0:02:20.240 It will probably provide the conditions for that miso to 0:02:20.400 --> 0:02:26.160 ripen into some really top notch gut flora. Well I'm 0:02:26.160 --> 0:02:28.760 grossed out now, are you really? Yeah? I found that 0:02:28.800 --> 0:02:32.760 stuff fascinating. All that your gut flora. It's a matter 0:02:32.800 --> 0:02:34.800 of personal taste. I guess. It's like people like the 0:02:34.800 --> 0:02:39.079 smell of their own poop. That's not two different things. 0:02:40.720 --> 0:02:46.400 Do you like the smelling your own poop? Great? Really? Yeah? 0:02:46.760 --> 0:02:50.640 I like all my smells. I got you. Do you 0:02:50.639 --> 0:02:56.080 like ice? Ay? Just I do? We're in one yeah, 0:02:56.560 --> 0:03:01.200 well can we be in a noisy age? It's hottest wherever, right, 0:03:01.480 --> 0:03:04.480 but the climb is not changing. Why this summer has 0:03:04.520 --> 0:03:09.040 been awful? Yeah, supposedly every year we just keep getting 0:03:09.080 --> 0:03:11.240 hotter and hotter. Yeah, And I'm like, I have a 0:03:11.280 --> 0:03:14.920 feeling here and Georgia, it's going to be hot into October. 0:03:16.040 --> 0:03:19.840 I noticed the change take place to day Oh really? 0:03:19.919 --> 0:03:23.920 Uh not me. I was out there this morning, but 0:03:24.080 --> 0:03:26.720 momo out well yeah, and I was like, oh, it's 0:03:26.880 --> 0:03:30.480 not muggy night. Nights are getting cooler. That's where it 0:03:30.600 --> 0:03:33.000 starts to change. Yeah, but it's still like up in 0:03:33.000 --> 0:03:35.320 the nineties during the day. During the day is still 0:03:35.440 --> 0:03:38.560 kind of nasty. But it feels different to me, like 0:03:38.600 --> 0:03:41.600 the air feels different. Yeah, not me yet. Yeah, that 0:03:41.720 --> 0:03:45.360 that first fall blasts I haven't experienced. Maybe it's seeing 0:03:45.400 --> 0:03:48.160 like cinnamon brooms and Kroger that's put me in the 0:03:48.200 --> 0:03:50.480 fall mood already. I'm just noticing it where it's not 0:03:50.480 --> 0:03:55.360 the Christmas decorations, right, yeah, Halloween stuff's been out since August. Man, 0:03:56.000 --> 0:04:00.520 just ridiculous. So back to ice ages. Um, like you said, 0:04:00.560 --> 0:04:03.240 we are actually in an ice age. To be specific, 0:04:03.600 --> 0:04:10.320 we are in the Holocene epoch right, yes, which features 0:04:10.360 --> 0:04:16.080 the Quaternary ice age, and specifically we're in the flandry 0:04:16.080 --> 0:04:21.280 and interglacial period. But still, even though it's interglacial, it's 0:04:21.320 --> 0:04:23.680 still an ice age that we're in. It's a mouthful, 0:04:24.040 --> 0:04:27.880 it is. Who wrote this? Was this? Molly? Molly Edmonds, 0:04:27.920 --> 0:04:30.440 our dear old friend. Yes, she she put out quality 0:04:30.600 --> 0:04:35.520 she did. Um. Yeah, Molly points out quite astutely that, uh, 0:04:35.600 --> 0:04:37.839 you know, if you look at Antarctica in Greenland, you 0:04:37.839 --> 0:04:41.840 still see ice sheets and um ice ages. Though are 0:04:42.440 --> 0:04:44.560 it's not you know, we don't have to have the 0:04:44.760 --> 0:04:46.720 entire or a third of the earth covered in ice 0:04:47.160 --> 0:04:49.400 to be in an ice age, because within an ice 0:04:49.400 --> 0:04:53.039 age there's periods of cooler weather and warmer weather, and 0:04:53.160 --> 0:04:57.120 right now that you know, glacials and interglacials respectively, and 0:04:57.200 --> 0:05:00.720 right now we're in an interglacial. That's all it is. 0:05:01.000 --> 0:05:02.960 But like I said, when people look around, they don't 0:05:03.000 --> 0:05:04.880 think of as being in an ice age, because we're 0:05:04.880 --> 0:05:08.040 just during one of those warmer periods, right. But I 0:05:08.080 --> 0:05:11.080 think so. I was reading this New Scientist article about 0:05:11.080 --> 0:05:13.039 I think it's called the History of Ice on Earth, 0:05:13.600 --> 0:05:16.960 and they said that there are basically three settings that 0:05:17.000 --> 0:05:20.960 the Earth has. UM greenhouse, which is basically there's no 0:05:21.040 --> 0:05:26.280 ice anywhere on Earth. UH. Ice house which is like 0:05:26.320 --> 0:05:29.920 an ice age glacial period where there is ice even 0:05:30.000 --> 0:05:33.560 like today there's ice on the Arctic and Antarctic caps 0:05:33.720 --> 0:05:37.760 right um. And then there's a snowball um setting the 0:05:37.800 --> 0:05:40.920 most fun of all, which is like the entire planet 0:05:40.960 --> 0:05:44.240 is frozen over the least fun of all. There have 0:05:44.279 --> 0:05:46.680 been periods of Earth's history where the whole thing was 0:05:46.760 --> 0:05:50.080 just a giant ball of ice. Yeah, if we want 0:05:50.120 --> 0:05:52.839 to talk about the you know, the I don't know 0:05:52.839 --> 0:05:54.400 if you want to call it the Big Ice Age. 0:05:54.480 --> 0:05:58.400 But when we think of the term ice age, we 0:05:59.000 --> 0:06:01.360 most people are probably talking about the one that began 0:06:01.400 --> 0:06:04.880 about seventy thousand years ago, uh during the Pleistocene era 0:06:05.520 --> 0:06:08.800 lasted about sixty thousand years UH. And if you're talking 0:06:08.800 --> 0:06:12.679 about the United States, uh, and the four major glaciations 0:06:13.520 --> 0:06:16.640 they hit the Midwest, the Nebraska and the Kanson the 0:06:16.720 --> 0:06:21.600 Illinois and the famous Wisconsin glaciation. Yeah, that's the one 0:06:21.640 --> 0:06:23.440 that just ended that. We just came out of the 0:06:23.480 --> 0:06:26.960 Wisconsin one, that's right. And they call him this because 0:06:27.000 --> 0:06:29.440 that's where they were geographically. Well that's where I think 0:06:29.480 --> 0:06:33.280 the greatest evidence of them has been discovered. Right. So, um, 0:06:33.640 --> 0:06:36.120 and in all this it's kind of confusing, actually, but 0:06:36.279 --> 0:06:39.839 just just the the current ice age that we're in 0:06:40.000 --> 0:06:43.800 started two point five eight million years ago, right, and 0:06:43.839 --> 0:06:46.280 again it's still going two point five eight million years 0:06:46.320 --> 0:06:49.599 to present, the quaternary ice age. Um. And so those 0:06:49.680 --> 0:06:53.119 little other subdivisions have to do with when the ice 0:06:53.200 --> 0:06:56.960 has been relatively scarce or when it's been all over 0:06:57.000 --> 0:06:59.719 the place. And then to make it even more slightly, 0:06:59.760 --> 0:07:05.119 can using during periods of glaciation. There's even periods where 0:07:05.160 --> 0:07:10.800 the glaciers retreat and advance. That's stadial and interstadial periods, 0:07:10.800 --> 0:07:13.360 and those tend to be a little more local. Uh, 0:07:13.400 --> 0:07:16.560 And and happened a lot a lot more quickly, and 0:07:16.680 --> 0:07:20.280 glacial or in an interglacial period, happened on the scale 0:07:20.280 --> 0:07:23.480 of tens of thousands of years. Yes, that's right. And uh, 0:07:24.640 --> 0:07:26.320 this is nothing new, Like you said, this has been 0:07:26.360 --> 0:07:29.560 going on since there was a planet Earth. But um, 0:07:29.600 --> 0:07:34.440 actually recognizing and and what is an ice age just 0:07:34.520 --> 0:07:37.239 sort of on the newer front, because in the old days, 0:07:38.120 --> 0:07:40.520 you know, they would see a big rock and they 0:07:40.560 --> 0:07:44.440 would say, boy, the thing looks like it slid down 0:07:44.440 --> 0:07:46.840 that mountain there, because you can see that mountains all 0:07:46.880 --> 0:07:49.640 carved up and this rock shouldn't be here, and that's weird. 0:07:49.800 --> 0:07:53.640 So that was the Great Flood of Biblical Times. We 0:07:53.720 --> 0:07:56.160 treated an episode on Yeah, that was a good one, 0:07:56.440 --> 0:07:58.800 and um, so that was kind of how things were explained, 0:07:59.440 --> 0:08:02.240 how these things ended up places where they probably did 0:08:02.240 --> 0:08:04.680 not start out. Yeah, people noticed that there was just 0:08:04.800 --> 0:08:09.679 weird stuff going on in the geography around them, right, Um, 0:08:09.720 --> 0:08:12.880 but they didn't they didn't place it correctly. Until it 0:08:12.960 --> 0:08:16.280 turns out the Swiss peasantry and some German peasants as well, 0:08:16.880 --> 0:08:20.360 started to notice that their glaciers were receding. And as 0:08:20.360 --> 0:08:24.240 their glaciers receded up there and say the Alps, it 0:08:24.440 --> 0:08:29.080 left some markings that they noticed also the same kind 0:08:29.120 --> 0:08:32.600 of markings further down the mountain. So the Swiss peasants 0:08:32.600 --> 0:08:34.520 put two and two together and said, you know what, 0:08:34.679 --> 0:08:38.200 I think the glaciers used to be way, way bigger 0:08:39.080 --> 0:08:42.720 than they are today, and that maybe that is what 0:08:42.920 --> 0:08:47.439 explains these boulders that shouldn't be here being here in 0:08:47.480 --> 0:08:50.240 the middle of this field. And I guess from what 0:08:50.360 --> 0:08:52.760 I can gather, it was kind of like common folk 0:08:52.840 --> 0:08:56.320 wisdom in some areas of like the Swiss Alps, long 0:08:56.400 --> 0:08:59.640 before science understood it. And it was actually a Swiss 0:09:00.000 --> 0:09:04.360 geologist who was the first one to advance a genuine 0:09:04.440 --> 0:09:09.599 bona fide hypothesis for ice ages. Yeah, Lewis Uh, I 0:09:09.679 --> 0:09:13.680 guess sees is how I'm gonna pronounce that. And um 0:09:13.760 --> 0:09:18.360 he in seven presented um his ideas about this glacial 0:09:18.360 --> 0:09:23.000 activity at a conference, the science conference, and everyone was like, yeah, 0:09:22.760 --> 0:09:25.640 m I don't know. I don't know about you. I 0:09:25.679 --> 0:09:27.880 don't know about that. Well, they didn't know about him. 0:09:27.880 --> 0:09:30.400 He was he was a smart guy, right, he was established. 0:09:30.400 --> 0:09:34.240 But they're like, you're just go back to your opium 0:09:34.240 --> 0:09:37.959 pretty much. And apparently his his first theory was that 0:09:38.480 --> 0:09:41.520 there there have been an ice age. It happened like 0:09:41.920 --> 0:09:45.920 very quickly. Yeah, he was off basically like night and day. Uh, 0:09:45.960 --> 0:09:51.199 and and that um it had followed a catastrophe, right, Yeah. 0:09:51.240 --> 0:09:54.040 I wonder if he would have that seems like the 0:09:54.080 --> 0:09:56.199 one thing that might have put them off. It was 0:09:56.280 --> 0:09:59.640 how unlikely that sounded right? Because he was wrong? Like 0:09:59.679 --> 0:10:01.600 I won. If you would have said it happened slowly 0:10:01.600 --> 0:10:04.440 over time, let's say, yeah, they may have said like, 0:10:04.480 --> 0:10:07.920 oh well, I'm not buy that he's presenting his finding. 0:10:08.040 --> 0:10:11.839 He's like, what do you guys want to hear? But 0:10:12.000 --> 0:10:15.000 I'll massage it in that way. Yeah, it happened overnight 0:10:15.040 --> 0:10:16.760 and they all just cross their arms. He goes or 0:10:17.679 --> 0:10:21.840 overnight over a very long period of time. Uh so 0:10:21.920 --> 0:10:24.800 before him though, um, quite a few years before him, 0:10:24.840 --> 0:10:31.079 there was a scotsman. Oh yeah, born in Edinburgh, Edinburgh, 0:10:31.760 --> 0:10:36.240 buried at Greyfriars Kirkyard. Wow, which did you ever go there? 0:10:36.480 --> 0:10:38.520 I walked past it. I never made it in Okay, 0:10:38.559 --> 0:10:41.480 well my hotel was right there, so I walked through it. Amazing, 0:10:41.640 --> 0:10:44.920 amazing cemetery. I went to Marry King's close instead, which 0:10:44.920 --> 0:10:47.200 is pretty awesome too. Oh you had to go to 0:10:47.200 --> 0:10:51.280 one or the other. They're close to each other. Um, 0:10:51.320 --> 0:10:53.320 there's only so much time in the day. Off not 0:10:53.400 --> 0:11:00.439 close enough? Uhive a man named James Hutton, uh man, 0:11:00.520 --> 0:11:03.720 this guy was He was a stud the father of geology. 0:11:03.800 --> 0:11:07.000 He had this idea that he he was one of 0:11:07.040 --> 0:11:09.040 the first people to look around and say, you know what, 0:11:09.120 --> 0:11:12.199 the Earth is always changing, Like if you look around 0:11:12.200 --> 0:11:14.400 and pay attention, look at it, that birds just died. 0:11:14.720 --> 0:11:17.960 Like he might sit for days and look and wait 0:11:18.000 --> 0:11:21.600 for something to move. But he said, the Earth is 0:11:21.640 --> 0:11:25.320 constantly changing, and I have an idea that it's probably 0:11:25.360 --> 0:11:27.680 always been this way. So if we look at what's 0:11:27.679 --> 0:11:30.440 going on now and we apply that to the past, 0:11:30.840 --> 0:11:34.160 we might come up with some pretty interesting stuff here, right. Yeah, 0:11:34.480 --> 0:11:37.080 he said that there's basically clues to the past in 0:11:37.120 --> 0:11:39.680 the present. Yeah, just like, look what's going on around you. 0:11:39.800 --> 0:11:42.360 This might have happened ten thousand years ago as well, 0:11:42.400 --> 0:11:45.720 and that might explain something like that boulder being someplace 0:11:45.720 --> 0:11:47.960 different exactly. And we keep going to the boulders. But 0:11:48.040 --> 0:11:52.200 the boulders are actually some really really high quality evidence 0:11:52.280 --> 0:11:56.640 for ice ages in general. Um, there's there. There's actually 0:11:56.640 --> 0:11:59.280 a term for it among people who study ice ages. 0:11:59.440 --> 0:12:03.360 They're called erratics. And an erratic is a very very 0:12:03.400 --> 0:12:06.520 heavy boulder, way too heavy to have been moved by humans. 0:12:07.160 --> 0:12:10.480 Um that is also too far from its point of 0:12:10.520 --> 0:12:14.000 origin to just say rolled downhill it doesn't make any 0:12:14.080 --> 0:12:16.720 sense that it's there, which is why it's called n erratic. 0:12:16.920 --> 0:12:19.960 There's some very famous ones. Um, there's one in the 0:12:20.040 --> 0:12:22.800 Swiss Alps. Uh, well, I'm sure there's many, but there's 0:12:22.840 --> 0:12:25.040 one in particular. This article mentions that's in the Swiss 0:12:25.040 --> 0:12:28.320 Alps that is, um, about fifty miles from its point 0:12:28.320 --> 0:12:32.600 of origin. There's one in Central Park that is many 0:12:32.600 --> 0:12:35.120 miles away from its point of origin. In New Jersey, 0:12:35.320 --> 0:12:37.439 it moved, tried to make it in the big city. 0:12:37.600 --> 0:12:39.960 It was a bridge and tunnel boulder, right. So, and 0:12:40.000 --> 0:12:42.239 that's actually one of the one of the ways the 0:12:42.280 --> 0:12:44.240 Germans figured out that there was such a thing as 0:12:44.240 --> 0:12:46.920 ice age because they said, see that bowler there in 0:12:46.920 --> 0:12:51.640 that field, I'm pretty sure that skinnin Avian rock, and uh, 0:12:52.000 --> 0:12:54.120 sure enough they were correct. And so you start to 0:12:54.160 --> 0:12:58.079 put all this stuff together, huge bowlders being moved, Um, 0:12:58.920 --> 0:13:01.800 valleys between mountains, carved out in a U shape rather 0:13:01.840 --> 0:13:05.840 than that telltale V shape that a river carves out. Um. 0:13:05.880 --> 0:13:08.560 These are clues. They're not well they are erratics, but 0:13:09.040 --> 0:13:11.800 their clues into the past. Yeah that when you start 0:13:11.840 --> 0:13:14.679 to put all of them together. The only thing that 0:13:14.679 --> 0:13:21.080 that really explains them, is huge, massive movements of glaciers. 0:13:21.400 --> 0:13:24.800 Glacial movement. Yeah. And and when you study that stuff 0:13:25.160 --> 0:13:27.640 and you look at these grooves and you study the boulders, 0:13:27.640 --> 0:13:30.880 you can actually make calculations. And it's amazing that way 0:13:30.920 --> 0:13:34.319 back then they were able to make these calculations. Uh. 0:13:34.360 --> 0:13:38.320 Agazz in particular and some other guys got together and 0:13:38.360 --> 0:13:42.480 they said that the present ice age at its peak, 0:13:42.559 --> 0:13:46.560 I guess, um, was about a mile thick of glacier 0:13:47.080 --> 0:13:51.560 A mile of ice. Yes, it's amazing yeah. Um. And 0:13:52.120 --> 0:13:56.280 further studies have concluded that in the last ice age, um, 0:13:56.320 --> 0:14:02.000 I guess there was Wisconsin glaciation. Um. The the about 0:14:02.000 --> 0:14:05.240 a third of the earth was covered in glaciers. Have 0:14:05.400 --> 0:14:08.000 we said that glacier as yet? I mean, it almost 0:14:08.000 --> 0:14:09.960 goes without saying, but just in case. Yeah, it's just 0:14:09.960 --> 0:14:13.559 really densely packed snow it is, and it snow that 0:14:13.559 --> 0:14:16.400 that isn't allowed to melt. It's it's cold enough so 0:14:16.440 --> 0:14:18.920 that it never fully melts. At the base, it forms 0:14:18.960 --> 0:14:22.240 to ice, and on top you've got more and more snow, 0:14:22.280 --> 0:14:24.640 and as more and more snow doesn't melt, the ice 0:14:24.640 --> 0:14:27.560 builds up thicker and thicker and just from the sheer 0:14:27.680 --> 0:14:32.920 force of these things mass encountering gravity, they can actually move. 0:14:33.120 --> 0:14:36.760 They're like very slow most of the time, very slow 0:14:36.840 --> 0:14:41.960 moving rivers of ice on a massive scale. Yeah, and 0:14:41.960 --> 0:14:44.120 and well we'll get to that later. I was gonna 0:14:44.360 --> 0:14:47.400 tease something out. Uh, should we take a quick break? 0:14:48.040 --> 0:14:50.360 All right, we'll take a break and we'll get back 0:14:50.400 --> 0:15:19.160 to a little more amazing glaciers. All right. So we've 0:15:19.160 --> 0:15:23.640 talked about the sheer size a mile a mile thick 0:15:23.680 --> 0:15:25.560 of ice. Yeah, and I said, like a third of 0:15:25.560 --> 0:15:28.760 the Earth. I think it covered seventeen million square miles 0:15:28.760 --> 0:15:31.840 of the planet during the last glaciation cubic miles, my friend, 0:15:31.880 --> 0:15:35.640 cubic miles, right, So junk is deep. Yeah, a mile deep. Man, 0:15:35.640 --> 0:15:39.840 That is nuts. Uh. So Antarctica had about ten percent 0:15:39.880 --> 0:15:42.720 more ice than it does now. And the big change 0:15:42.960 --> 0:15:46.000 with the big difference, Uh, what sets that ice age 0:15:46.000 --> 0:15:49.920 apart was the amount of activity in the northern hemisphere. 0:15:49.920 --> 0:15:52.440 It was very unusual to have the amount of ice 0:15:52.600 --> 0:15:56.720 in North America and Europe extending down like through the 0:15:56.760 --> 0:16:00.120 midwest of the United States. It was it was a 0:16:00.160 --> 0:16:03.160 new scene, a new chili scene. Ye, a whole new 0:16:03.240 --> 0:16:06.480 jam basically, and Chuck. I mean like it was largely 0:16:06.520 --> 0:16:10.840 in North America, but this also, um really covered a 0:16:10.880 --> 0:16:14.120 lot of Europe too. I mean like Ireland was covered, 0:16:14.200 --> 0:16:18.760 Germany was covered, Scandinavia was covered by ice, and basically 0:16:19.040 --> 0:16:22.280 everything that wasn't covered by ice, and Europe was a tundra, 0:16:22.760 --> 0:16:25.720 very much like Siberia is today. I actually I saw 0:16:25.760 --> 0:16:28.040 a documentary on I think it was a History Channel 0:16:28.200 --> 0:16:33.320 show about the Last Ice Age, and um, somebody figured 0:16:33.360 --> 0:16:35.520 out how much all of that ice weight are you 0:16:35.560 --> 0:16:40.360 ready for this? Basilion pounds? This might be more than 0:16:40.400 --> 0:16:45.280 a bazillion sixty eight thousand trillion tons was the total 0:16:45.320 --> 0:16:48.080 weight of the ice of the Earth on the Earth 0:16:48.160 --> 0:16:50.760 during the Last Ice Age, during the last place. How 0:16:50.760 --> 0:16:53.920 many maxes that have no idea? It's like more than 0:16:54.040 --> 0:16:59.320 a hundred uh well a North America loan about thirteen, Um, 0:16:59.520 --> 0:17:02.920 I'm sorry, about ten million square miles of ice. And 0:17:03.400 --> 0:17:05.320 you know this all came from the ocean, which means 0:17:06.040 --> 0:17:08.920 the ocean level was hundreds and hundreds of feet lower 0:17:09.240 --> 0:17:11.560 during this ice age. Yeah, like Canada is used to 0:17:11.720 --> 0:17:14.919 having large parts of it being covered by glacier, the 0:17:14.960 --> 0:17:17.440 United States is not used to this, but it came 0:17:17.480 --> 0:17:21.240 all the way down into the plains in some cases, 0:17:21.720 --> 0:17:26.640 and basically from New York over to Washington State totally 0:17:26.680 --> 0:17:32.679 covered by again a mile thick sheet of ice. Like 0:17:32.680 --> 0:17:35.520 you can ice skate on that without worry. You're not 0:17:35.560 --> 0:17:39.200 gonna fall through, it's still gonna crack. Did you ever 0:17:39.240 --> 0:17:42.480 do that growing up? Did Ohio? Like like you'd skate 0:17:42.520 --> 0:17:45.119 on lakes? Yeah, And we were never allowed to do 0:17:45.200 --> 0:17:47.880 that until my dad went out and stomped on it, 0:17:47.960 --> 0:17:50.680 like jumped up and down, and if he didn't go through, 0:17:50.760 --> 0:17:52.639 then we were allowed to skate. He's like, kids, if 0:17:52.680 --> 0:17:55.359 I die right. It wasn't. It wasn't the most fool 0:17:55.400 --> 0:17:57.959 proof technique, but it was nice and dad to do 0:17:58.040 --> 0:18:00.960 that for us. I don't know, think I'm not much 0:18:00.960 --> 0:18:02.879 of a worry word, but I'm that still would have 0:18:02.880 --> 0:18:04.520 like creeped me out. I've seen enough movies, you know, 0:18:05.160 --> 0:18:08.640 left under ice. So the Mammi River would freeze over, 0:18:08.760 --> 0:18:10.480 but we weren't allowed to skate on the river. Some 0:18:10.520 --> 0:18:12.760 people did, we weren't allowed to. Instead, there was a 0:18:12.800 --> 0:18:16.120 golf course with ponds that would freeze pretty good, pretty good. 0:18:16.560 --> 0:18:18.320 There was your You weren't going to fall through these 0:18:18.320 --> 0:18:22.760 small ponds pretty rough though, right, like skating on it's 0:18:22.760 --> 0:18:25.639 not it depends it depends on and I don't remember 0:18:25.680 --> 0:18:27.800 what it depends on. Yeah, it's it's never like an 0:18:27.800 --> 0:18:32.560 ice drink. But certain type of weather, maybe non windy weather, 0:18:32.600 --> 0:18:35.080 I think is what it was, because then like if 0:18:35.080 --> 0:18:37.359 there was kind of like a choppiness to it from 0:18:37.400 --> 0:18:40.800 the wind, it could freeze like that freeze choppy, Whereas 0:18:40.840 --> 0:18:43.280 if it wasn't windy, I would guess it would it 0:18:43.320 --> 0:18:47.000 would be smoother. So sometimes it was pretty smooth. Other 0:18:47.040 --> 0:18:48.639 times you're like, I can't even skate on, but your 0:18:48.720 --> 0:18:51.240 dad would drive a zambonie out there and fix it 0:18:51.280 --> 0:18:54.320 all up. It over and if the zamboni didn't fall through, 0:18:54.359 --> 0:18:57.520 then we were allowed to skate, right. I just picture 0:18:57.520 --> 0:18:59.640 of the zamboni falling through. But it's a little pond, 0:18:59.680 --> 0:19:04.120 so you're a'd still like just a bove. I feel 0:19:04.119 --> 0:19:06.560 like I missed out, though, I mean not that life 0:19:06.600 --> 0:19:09.160 is over. You can still skate on ponds. I don't 0:19:09.200 --> 0:19:13.440 picture myself going to Minnesota in the in the winter. 0:19:14.000 --> 0:19:17.080 Give it a try. The trade off it wasn't It 0:19:17.119 --> 0:19:19.560 wasn't a very good trade off because the winners are 0:19:19.560 --> 0:19:22.359 pretty brutal. Yeah, like if you have local ponds that 0:19:22.400 --> 0:19:26.280 freeze over, you're cold too. I still feel like I 0:19:26.359 --> 0:19:28.919 missed out. Yeah, I mean you're fine. It wasn't that 0:19:28.920 --> 0:19:30.679 big of it was just teasing when I said, you 0:19:30.720 --> 0:19:35.000 did miss that. Uh all right, So people are skating 0:19:35.040 --> 0:19:37.440 all over the world. A third of the world people 0:19:37.440 --> 0:19:41.040 are ice skating on during during the ice age UM 0:19:41.160 --> 0:19:44.560 and like we mentioned these things, UM they've been described 0:19:44.600 --> 0:19:49.760 as bulldozers just plowing through uh the earth basically um 0:19:49.880 --> 0:19:53.719 leaving large swaths they call it glacial till. This debris 0:19:53.800 --> 0:19:57.200 that they leave behind, and these are you know, once 0:19:57.240 --> 0:20:00.000 you figure out how it works, the evidence is every 0:20:00.080 --> 0:20:03.719 where of exactly what happened. Yeah, Because as these glaciers 0:20:03.800 --> 0:20:06.840 move and that ice that has formed the basis of 0:20:06.880 --> 0:20:10.879 the glacier is in contact with the earth below it, 0:20:10.880 --> 0:20:13.479 it's picking up all sorts of crud that all that 0:20:13.640 --> 0:20:17.199 to breathe that glacial till you said, erratic boulders. And 0:20:17.200 --> 0:20:21.600 as it's doing this, it's actually creating a um a 0:20:21.760 --> 0:20:24.480 scrubbing mechanism. Right. So, like you said, if you look 0:20:24.480 --> 0:20:29.760 around at mountains and and and valleys with exposed rock 0:20:30.280 --> 0:20:34.160 that were um rubbed by glaciers. There's gonna be crazy 0:20:34.240 --> 0:20:38.600 grooves worked into them. Some look like roads almost, yes, um, 0:20:38.680 --> 0:20:42.080 some are kind of polished and rounded, And it's all 0:20:42.119 --> 0:20:45.240 from this glacial activity rubbing stuff over the tops of 0:20:45.280 --> 0:20:48.240 these mountains. It's pretty interesting stuff. And then other things 0:20:48.320 --> 0:20:50.280 like you'll know, you know, you'll see like a movie 0:20:50.320 --> 0:20:56.480 where um, this incredibly beautiful uh like river Valley has 0:20:56.760 --> 0:21:01.040 just gravel everywhere, like just scattered all all throughout, like 0:21:01.119 --> 0:21:04.600 the valley floor. That's not supposed to be there. The 0:21:04.680 --> 0:21:07.800 glacier deposited that. That's right, it's more evidence of the 0:21:07.920 --> 0:21:11.120 ice age. Yeah, that's interesting to think of it. It's 0:21:11.160 --> 0:21:13.280 not supposed to be there. No, and you think of 0:21:13.320 --> 0:21:15.679 that like that's what that's what that looks like. You know, 0:21:15.760 --> 0:21:18.520 of course that's what it's. That's that's that's supposed to 0:21:18.520 --> 0:21:20.800 be there. But no, it's technically not. Had we not 0:21:20.920 --> 0:21:25.360 had um these glaciation events, that stuff wouldn't be there. 0:21:25.640 --> 0:21:30.520 And that fascinating earth science. Uh is that your favorite science? 0:21:31.320 --> 0:21:34.480 I think it's become it. Yeah, yeah, it really does 0:21:35.280 --> 0:21:40.280 get me jazzed, all right. So it wasn't just um, 0:21:41.280 --> 0:21:44.200 the direct path of these glaciers that was affected out 0:21:44.200 --> 0:21:49.800 on the edges of these massive moving sheets of ice. Um, 0:21:50.000 --> 0:21:53.560 you had things like arctic deserts, and you had these 0:21:53.680 --> 0:21:57.320 big areas of dusty wind. Uh. And there's actually a 0:21:57.359 --> 0:21:59.639 few ways to pronounce this l O E s s 0:22:00.160 --> 0:22:05.240 heard everything from lowest to lows to less I like lowest, Yeah, 0:22:05.320 --> 0:22:09.399 like lowest too. Um covering all over the earth basically, 0:22:09.560 --> 0:22:12.720 and this is created by those glaciers just like grinding 0:22:12.760 --> 0:22:16.280 into the earth. Yeah, um, stirn everything up right, and 0:22:16.320 --> 0:22:18.720 then the wind just comes and picks it up, the 0:22:19.160 --> 0:22:22.119 finest of the particles and just deposits them. So in 0:22:22.160 --> 0:22:26.000 some places you had so if if your area wasn't 0:22:26.040 --> 0:22:29.199 covered by glacier, that didn't mean you weren't affected by 0:22:29.200 --> 0:22:32.840 the glaciation, because you would have these lowest deserts are 0:22:33.200 --> 0:22:36.480 glacier glacial deserts that formed. And in some places the 0:22:36.520 --> 0:22:39.760 lowest was like twenty ft thick, and apparently it's still there. 0:22:39.960 --> 0:22:44.000 In much of the Midwest, the sub straight below the 0:22:44.080 --> 0:22:51.359 soil is lowest, deposited from these lowest deserts UM. And 0:22:51.400 --> 0:22:53.560 so you would think when you hear about this kind 0:22:53.560 --> 0:23:00.360 of activity that it had to be like hundred degrees chillier, right, 0:23:00.680 --> 0:23:03.960 or fifty or forty even, but it was only about 0:23:04.000 --> 0:23:08.720 ten degrees fahrenheit about five point six celsius lower uh 0:23:08.720 --> 0:23:12.720 than temperatures now, which it's it wouldn't think that that 0:23:12.760 --> 0:23:15.920 would be enough, right, But it's not all just about 0:23:15.920 --> 0:23:18.920 the temperature. That's kind of the point. No, The point 0:23:18.960 --> 0:23:21.640 that Molly makes is that it's not like, oh, it's 0:23:21.680 --> 0:23:24.280 just so much colder than it was before all the time. 0:23:24.760 --> 0:23:29.199 The key to an ice age um forming glaciers a 0:23:29.200 --> 0:23:33.320 glacial period is that this the time when it's supposed 0:23:33.359 --> 0:23:37.320 to actually melt, is colder than usual, so that there's 0:23:37.440 --> 0:23:41.400 less melt than than before. And the less melt you have, 0:23:41.920 --> 0:23:44.439 the more chance you have for snow to fall and 0:23:44.520 --> 0:23:47.119 make up for whatever melted and actually add to it, 0:23:47.359 --> 0:23:50.360 which means that the glaciers growing. As long as more 0:23:50.400 --> 0:23:52.960 snow is added to the glacier than it loses during 0:23:53.000 --> 0:23:56.159 say the summer months, your glaciers growing. Yeah, and if 0:23:56.200 --> 0:23:58.919 it's not losing much, it doesn't take much snow. And 0:23:59.000 --> 0:24:04.240