SIO462: The Day the Dinos Died

Transcript

This transcript was generated automatically and may contain errors — the audio is the record.

0:00:16 Thomas: Hello and welcome to Serious Inquiries Only. This is episode 462. I'm your host, Thomas Smith. And I'M SO EXCITED ABOUT TODAY'S EPISODE. We've got everyone's favorite dino... Well, I shouldn't say dino expert, but everyone's favorite person who loves talking about dinosaurs and is an expert in certain areas of biology, Eric Jaffe. And this is one we've wanted to do for a while that is so fascinating to me. He's going to be talking about the day the dinos died, essentially. What happened? What do we think happened? What do мы know? Does the evidence show? And just what was it like for a giant meteor comet? I always forget the proper, I think it's meteor, right? Meteor, right oh happened how did that take everything out how did it not take everything out like I my mind is blown that something like that could happen and stuff survives like it's so crazy um those questions and more, this is a really fun one if you've ever wondered what it was actually like. Um, our best kind of approximation summation anyway, when a giant thingy took out a lot of life on this planet and was, I think, pretty sure the only reason we're here today. I think it sort of made room for us. So what did that look like? Do we know about that? All kinds of cool stuff. And Dr. Eric Jaffe is always so much fun. His enthusiasm is infectious. So really excited to bring you this one. Let's see, any updates? Going to be a lot stuff coming out at the end of the month, as kind of is usual, although I promise we're working on it. We're going to have some sort of special Where There's Woke coming out. Were working on the other series, of course, but this election stuff is just too much all over my mind, the rally in New York. There's so much to talk about there, And we're going to be putting that out at end of the month here in the next few days. It's really interesting. We went through that whole rally. Also some stuff about polling, like there's people who think that the polling has been kind of rigged by Republicans. I want to talk about that. There's just so much stuff that obviously is time sensitive that I need to put out right away. And the other stuff can always wait a little longer because it's not necessarily time sensitive. So expect releases over there. Expect releases on Gavel Gavel. About finishing up that trial. So much fun over on patreon.com/gavelpod. so the end of the month is a lot of fun. The end ofthe month, if you are into my podcast, is Christmas. If you hate my podcast, I suppose it's anti -Christmas. It's about that. If you hate My Podcast, you're probably not listening. So I know who I just apologized to. Anyway, that said, please support the shows. Really, truly, it's the only reason we can do all this. It's the only reason we can bring you delightful guests like Dino Expert, Dr. Eric Jaffe. Please support the show, patreon.com/seriouspod. appreciate those who do. And also, if you can't support the show, please write us a good review somewhere, you know, whether it's Apple Podcasts or whatever, or share it with somebody. Word you so much to those who do. And after this break, we'll find out who killed all those dinosaurs and why. And welcome back to the show. Everyone's favorite dino expert. Probably won't say you're a dino talker about of dinos. Dr. Eric Jaffe, how are you doing? Oh,

0:03:19 Eric: I am doing pretty well. We just had our first day of students in the building for orientation, so school year's picking up again, kind of getting into that nice rhythm again.

0:03:26 Thomas: I remember we were trying to get recordings done before that happened. And yet here we are. So thanks for taking the time. I'm so excited. This This is one you've mentioned in your list of possibilities. And I was like, oh, I can't wait for this.

0:03:31 Eric: Worries. And I think this one's good because it's a story that I think we're all somewhat familiar with, but it's great kind of demonstration of just the scale that's involved in global processes that I don't think we encounter in our everyday life.

0:03:53 Thomas: Where do we want to start? Generally, I feel like everyone knows, you know, Big Rock probably did it. Is we start there?

0:04:00 Eric: I was actually going to start on why this one kind of captures the imagination of everyone involved. And I think it's important to note that, like, this actually isn't the biggest mass extinction on Earth or in Earth's history. This is only about third on the list of great mass extinctions, so I thought we would very quickly go through those.

0:04:18 Thomas: But in size or in number of species because I feel like by volume like it's got to be wow

0:04:26 Eric: Actually both. What is unprecedented is the time scale that we're talking about. So I thought it would be helpful to kind of go through. There are five major mass extinctions in Earth's history. The Cretaceous one, the one that killed the dinosaurs, is actually the fifth in a line of them. And I thought It would be important to kind Of very quickly go through those first four and just show how catastrophic and just how different this one is.

0:04:51 Thomas: Yeah, sure, that.

0:04:53 Eric: Why don't we hop in our time machine. And there's a couple of things as we go through the story of death on earth that I kind of want us to keep in mind. So this may just be because I'm kind of in back to school mode. But I've always heard a lot of people say like, oh, they don't teach science right in schools. And that's the big problem. And they only teach what it is, but not really how to think. And I thought as we Go through this story, we layer in some of the concepts and kind of ways that we teach science in the classroom to address that because this is a great model system for kind of going over the new ways of thinking about science in the class. A big part of that is before people used to always say, why would I need this topic? Or we're just learning random facts about the cell, random facts, about mitochondria. And a big shift that we're doing in science pedagogy is looking at what we call cross -cutting concepts. This one is a a great example of some of those cross -cutting concepts. In particular, in this episode, we're really going to look at things like scale, proportion, and quantity, how little things add up to just truly massive kind of mind -blowing numbers. We're going to look at how all of this is just kind of the logical consequence of energy and matter transferring through systems. And then we're going talk about those systems and how they have periods of stability and then periods of violent disruption and change. Big theme in kind of what we're going to be talking about as we work our way through the periods of death in Earth's history are those cross -cutting concepts and how very similar principles in science kind of re -show themselves over and over and again and form patterns that we can study. And so as we go through our list of mass extinctions, try and pay attention to what are the commonalities and then what's so different about the dinosaur extinction. That's really where we're going to kind of put a bow on this episode. So with that being said, let's get in our time machine and let's go all the way to about 450 million years ago or so to the Ordovician period. Now, the Ordovician Period was

0:06:53 Eric: Our first great mass expansion.

0:06:53 Thomas: I don't think I've ever heard of that one. Really? Must've been a bunch of bullshit died that nobody cared about.

0:06:59 Eric: That's actually kind of true because in million million years ago, we haven't had vertebrates on land yet. We haven't had the development of many of the things that we actually care about. And the land was actually formed by land terrestrial plants, and then insect species. So so there wasn't really a lot of these kind of things that we would care about, which is actually why we're going to completely skip over the first great mass extinction event, which happened about 2 billion years ago, which was the Great Oxidation Event. This is called the Oxygen Revolution. And what happened there was basically things started doing photosynthesis. Now, we think of oxygen as like a fundamental property of life because we are one of those things that have a eukaryotic cell with mitochondria that process it, but that eat plants that use oxygen to turn into food, right? So we thinkof oxygen as a fundamental process because it's part of that respiration, right, that breathing. But bacteria don't have lungs, they don't respire. And they actually use different chemicals in order to do their metabolism, in order for it to process energy. And then these chloroplasts, and these blue -green algae more specifically, started coming and doing photosynthesis. And it put all this oxygen in the atmosphere that was actually poisonous to these microbes. And so there was a huge dying about about 2 billion years ago, when oxygen, which kind of reshaped what life will look like, got rid of the first kind of generation of life. They didn't really get rid of it because there's plenty of non -oxygen -using bacteria now, but they really changed the paradigm.

0:07:16 Thomas: The big giant bugs. Whoa. 2 billion. Wow. Right.

0:08:33 Thomas: Well, that's fascinating because it's not like that was even, I mean, not that this stuff had intentions really, but at all, but like, it's Not like that. Was like, Oh, they were over hunted or some new predator. It sounds like that was like a byproduct of just some totally unrelated way that an organism or two or whatever, we're going to live. And it's like, oh shoot, that just sucked out all the, well, not the oxygen, that's just put in all the oxygen in the room.

0:08:58 Eric: It's the opposite, yes. That's going to be one of those patterns we see, that a lot of times with these mass extinction events, a new organism, a New Kind of Process in Earth's systems develop that kind of change the fundamental composition of either the atmosphere or the oceans. And that just causes devastation in general. We're going to put a little pin on similar patterns about new organisms coming in and kind of terraforming the globe. And that brings us to the Ordovician. Ordovision was, again, 445 million years ago. And this is is what I would call like one of your stereotypical mass extinctions, in that it either happened very quick on the geologic timescale, we're talking, you of thousands of years, but more likely, it happened over about seven, what we call pulses, right? Things that are vast kind of bursts of extinction, each about 2 million years long, over the course of millions of years. And so in this Ordovician event, what really was affected was oceans and not the land because we didn't have that much land animals yet. But roughly 85 % of all marine species died between these two pulses.

0:10:07 Thomas: But when you talk about that timescale, it's interesting to call it an extinction, you know? Cause it's that's so long, you know, I don't know, what would you consider normal, because humans have been around for something like one to three hundred thousand years, right, in our current form, it's like we could be being extinct that whole time, we could be, we could begin, if an extinction could take millions of years, our whole life could be an extinction

0:10:33 Eric: We will get to that at the end of this episode, actually, because we're actually in the process of the sixth mass extinction, but I don't want to kind of bury the lead there. But you are right that when we're talking Talking about geologic timescale, we have a hard time because of the way that we evolved in a day to day sense. We have a heart time wrapping our minds around the scales involved. And that's why I wanted to put a pin on kind of keeping that scale in mind. This is a pretty quick extinction event, but you're still talking about millions of years that's happening where all this 85 % of marine species died.

0:10:38 Thomas: Spoiler yeah yeah

0:11:07 Eric: This one, the reason why I say it's a pretty stereotypical kind of mass extinction is because it's caused by a number of environmental factors. That first pulse that really started the extinction event was really caused by glaciation, right? The cooling of the atmosphere and then the sea levels are treating into ice caps, right. That's going to drop those CO2 levels and that's gonna change the environment very, very quickly, right, then Then right after a period of warming happened, and then all of that sea ice melted, changing again, the stuff, but more importantly, a period of anoxia and acidification happened. And what happens in anoxía is basically the oxygen is lower than it needs to be. So now we have the opposite problem of that first extinction event, right? We need that oxygen, but it's being removed from the oceans. And not only that, the oceans are getting more and more acidic. Acidic. And the reason why that's so important is because the things that kind form the base of our food web in the ocean, because there aren't grass and trees and plants, right? You can't have your herbivores in the Ocean. Instead, you have photosynthetic microorganisms and then small invertebrates that would eat those. And those small invertebras typically make their shells out of calcium carbonate, right? Those calcium carbonates shells dissolve in overly acidic conditions. And so when you lose that base of the food web, the rest of the Food Web in the ocean collapses. And that's what we see happen in the Ordovician. But that's also why it takes a fair amount of time because it's gonna take a while for all of these cascading effects to become more and more pronounced over time. Was actually the second biggest extinction event in Earth's history at around 85 % of life or known species being wiped out. Now fast forward about 70 million years to the Devonian period. And again, now we're starting to get colonization of animals onto land. So now we really have insects and small invertebrates on land. We have our tetrapods starting to develop from fish into the more kind of lungfish, tectolic and things that will start to take those first steps on land. Most importantly, because we have land plants, they are really messing up the freshwater system that used to not have any symptoms of life, any byproducts of life filtering through their waters, right? So what happens is as these processes of life on land are being filtered into the ocean, they're going to dump new nutrients into the water systems. They're they're going to alter that chemical balance again. There was also probably a period of volcanism, volcanic that is increasing the acidification of the oceans. And just like with the last time, we get a slight period of cooling, followed by that ocean acidification, subsequent warming, and then death in the oceans, and in this one, about 75 % of marine life died out. And this again happened over around the course of about 13 million years. So again, Again, we're talking about a large timescale in our view, but a very short timescale on Earth where the oceans are getting deprived of oxygen. They're becoming more and more acidic, and that causes a collapse of that ecosystem in the ocean. And the ocean is really the key to life in our planet. But notice again, it's also because there are patterns to this. There's also that effect of new organisms altering the systems, altering the balance of Earth, and then having that have cascading effects. Now, I should mention that there are a couple of extraterrestrial kind of suspects in this thing, right? Are some impact craters, including one that might be timed around that first pulse of extinction, but there's none that were dated precisely enough and none that we can really definitively time. But there is increased oxygen damage in the fossils in the strata of rock. And I should mention, the way that we know extinctions happen is by looking at the rock, right? Forms layers over time. If you've ever been to like the Grand Canyon, you may notice this. And this may sound obvious, but the rock at the bottom of that layer is going to be your oldest rock. And then over time, it gets compacted and pushed down by the elements in the environment, and it forms those nice compact layers. And so when we're talking mass extinction events, we're really talking about, you look at the rock, and at lower levels, you see abundant types of creatures, right? Whether you're talking about your sea invertebrates, your dinosaurs in the case of the Mesozoic. And then above a certain layer at a different time period, there is a sharp shift in the type of fossils you get. They become much less common and much less diverse. That's typically what we mean by we're seeing a mass extinction. We're losing the fossils we had at lower levels. And we're now not seeing like a good recycling for at least a long sustained period of time before there's recovery and a new set of fossils taking over. So when I say that there's increased oxygen damage in fossils at that Shroud of Rock, what I mean is that the animals at that time were in an environment showing oxygen damage. And that led to a really interesting hypothesis that it may have been caused by a neighboring supernova.

0:11:07 Thomas: Interesting Interesting.

0:16:16 Eric: Now, here's one where I want to layer in kind of some of those classroom techniques that we learn in school these days that we might not have done in the past. In the past, you probably would get a piece of information that says something like, And one theory is the supernova. Summarize the evidence behind why this is the case. Whereas what I would likely do first is I would ask my students, what prediction can you make about whether a supernova would be the cause of the dinosaur? What evidence would you look for and how would you find it? And it's only after they have a chance to be wrong that I would then try and give them right answers. And so at every time, what I'm going to try and do with my students is I'm gonna try and probe them into making predictions and kind of coming up with their own hypotheses. So I just wanted to put a pin in that because the prediction scientists would do, and the thing that we're still looking for, is if there was a supernova, you would expect certain types of elements in those rocks that's evidence of that supernova. So, for instance, if there is increased plutonium isotopes in those fossil rocks, that would be a very good evidence that there was supernova because I'm guessing there wasn't actually atomic weapons back in this time

0:17:22 Eric: Period.

0:17:23 Thomas: Well, why don't you, uh, refresh us on, our excuse supernovas. So is that, is, is the way that that would cause extinction because of like, what is it? Radiation or what does it do exactly?

0:17:32 Eric: Exactly it would be like x -ray and gamma ray burst that that's actually one of the scariest thing um about like living on a planet in space is that there are gamma ray bursts that could happen theoretically and there's just nothing we can do about it just a game over thank you for playing that too but uh this time we really do have the suspect nailed down so we've got one more extinction to talk about before we get to the dinosaurs and then I promise the rest rest of the episode is all about them.

0:17:41 Thomas: Plus crime is pretty scary too. Yeah. So, does that finish that one? Are you, so are you saying there's no evidence of that or was there evidence of that?

0:18:02 Eric: So there's no evidence yet. Right now, all we have is that there's anoxia, and there's ocean acidification, and then 75 % of marine life died out. That combination of anoxio and ocean acidication is a really devastating one -two punch for the oceans. It's why, if you remember when you mentioned on the Brett Weinstein episode what I'm afraid of, I mentioned ocean acid. And that's exactly why. This is why I'm It's called the Late Permian Extinction, or just known as the Great Dying. And this is the one that helped set the stage for the dinosaurs. It's the one before the end of the Paleozoic and the start of the Mesozoical era. One happened pretty quick. It happened at the low end of 50 ,000 years to a high end of a couple million years. It's likely that all terrestrial animals died out within those 50, 000 years, period. Yep.

0:18:56 Thomas: That's That's crazy.

0:18:57 Eric: And it's characterized by a 500 ,000 year thick layer of altered carbon composition, which basically, again, is showing that our oceans have disrupted chemistry. We have this massive die off of terrestrial animals that's causing that carbon composition. Right. And we lost around 95 percent of all life on Earth on this extinction event. And this was likely caused by volcanism, right? Volcanoes are once again, one of those main culprits in our extinction event. And tell me if this sounds like a pattern for me. It led to a rise in ocean acidification and anoxia in the oceans. Led to huge rise in global temperatures. And I want to put the scale of this in perspective. Warming is a huge problem in today's world, right the industrial revolution. The concentration of CO2 in the atmosphere is about 200 parts per million, right? So for every million particles of air, about 200 of those will be carbon dioxide. Nowadays, and we've seen the devastating effects that this has caused on our climate already, it is around 400 parts per billion. So we've doubled that number since the start of the Industrial Revolution. Obviously change depending on whether you're in the cities or not. But in general, that's the global average. Average. At the Permian extinction, the CO2 levels were estimated to be around 2 ,500 parts per

0:20:19 Eric: Million. We are talking just a devastatingly bad climate to live in. And that's why about 70 % of terrestrial life became extinct within that 50 ,000 year period. 95 % of marine life, and because marine life dominated, around 90 to 95 % percent of all life on Earth died. There are some good things about that, right? When you have that much death, it leaves a lot of ecological niches to be filled. And it kind of reset the reptile deck for the Triassic period. And that allowed for those pelicosaurs that we talked about last time, right? Our synapsids like Dimetrodon, and then also our dinosaurs. So this is really another example of a lot extinction freeing up ecological nichers, and the new animals coming through. And that's what you'd see in the fossil record. You'd see basically a lack of fossils for a a certain time period. And then you would start to see new forms recovering, new forms becoming present. And that's typically how you know that you're dealing with a mass extinction. So overall, to sum up, I would say these are the patterns we got from our previous five mass extinctions, right? Usually a loss of marine life more than other types because of the sensitivity of oceans and the interconnectedness, right. Usually caused by anoxia and ocean acidification. Our fossils are going to disappear very quickly from those strata on a geologic timescale, and they're going to happen between thousands of years to millions of years in their duration.

0:21:42 Thomas: What if there was some event that just like destroyed fossils? Like literally the, there's some like extreme event that somehow affected only the fossils at a certain time.

0:21:49 Eric: Yet, that would be very tough because the fossils wouldn't form until after the extreme event.

0:22:01 Thomas: No, I mean, it somehow would have have to destroy like yesterday's fossils you know it'd have to be it wouldn't be the one

0:22:05 Eric: Why don't we hold that question until we talk Talk about the impacts of the asteroid.

0:22:09 Thomas: You don't have to ever answer that question it's fine ah

0:22:12 Eric: Well, what I'm going to say is once you hear the impacts of the Asteroid, I think you can say we've done the safety check and the fossils are generally safe. That isn't to say, and we will get into this, but that isn't to say that no fossils were probably destroyed in that event, right? It's just that, again, Earth is so big, its fossil layer is so large, that complete destruction is usually off the table. Now we have this kind of pattern developing Where every 100 million years or so to 50 million years, we have this mass extinction event. It's usually caused by, or at least precipitated by ocean acidification and anoxia. There's usually causes that come from things like volcanism, maybe our extraterrestrial events like supernovas or asteroids, right? Then the last thing I forgot to mention is the thing that's happening all the time. Our plate tectonics are constantly moving and that's going to shift a lot of things like ocean currents. Right. Way heat is distributed throughout Earth's system. And so every once in a while you can have really disruptive plate tektonics that help build into that story of volcanism to ocean acidification. Right. So typically with these mass extinction events, it's never just one thing. It's kind of multiple straws that break the camel's back. Notice how a lot of these stories start not with asteroids, but with really small stories of metabolism, of precipitation and runoff, right? That's what I mean by scale and proportion. These really small changes are what lead to the catastrophic stuff. So just keep that in mind. Now we're ready for the KPG the KPG extinction.

0:23:45 Eric: Yep, that stands for is the Cretaceous to Paleogene extinction. Reason why it's a K instead of a C is there already is a C in geologic time and that's the Carboniferous period. This is actually where we get most of our fossil fuel whenever people say that your car runs on dinosaurs. We actually haven't had the time yet to have our cars run on dinosaurs, but they're actually running on are forests from the Carboniferous.

0:23:50 Thomas: I was gonna say what yeah who has the time hmm that's so much less fun to say

0:24:11 Eric: Is, which is why I think I'm fine with leaving the dinosaurs.

0:24:13 Thomas: So so you're saying that we're our cars run on stuff older than the dinosaurs dinosaurs wow that's

0:24:17 Eric: Yes, they run on really, really ancient plants. Some of the first plants to colonize during that actually Ordovician period would be like right around that Carboniferos.

0:24:26 Thomas: Crazy could could they someday run on dinosaurs or and

0:24:30 Eric: Yes, just give it another like 100 million years or so.

0:24:32 Thomas: Hopefully we have electric cars by then we'll see

0:24:36 Eric: I mean, we've got our best, right? Elon Musk is on it. Okay, so let's set the stage for the Cretaceous period. It is at the end of the Mesozoic era, right? The Mesozeic era consisted of three periods itself, the Triassic, the Jurassic, and then the Cretaceous period. Jurassic period is kind of what most people think of as the heyday of the dinosaurs, right, where it had its height of species diversity, it had it's kind of midpoint of the dinosaur reign, but it's actually not where most of the most famous dinosaurs come from. It's got its stegosaurs, it got its brontosauruses and other types of sauropods, but a lot of the truly iconic ones are actually in this late Cretaceous period. Do want to point out, because this will be important for kind of thinking about what might've caused it, is this is also an interesting time in the Mesozoic era because our continents are starting to form the shapes that we could visibly recognize. So one thing I would do with my students is I would actually give them a map of the world and I cut out all of the continents that are in the Cretaceous and I'd ask them to reform earth, right? And see how they fit together so that you can actually see that North America is in a spot that's pretty similar to North America now. South America is already separated from the two major continents that it was attached to, Africa and Europe, and it started to migrate forming the Atlantic Ocean, right. Now we have oceans developing, whereas before, for most of the dinosaurs, we had Pangea with its major subcontinent, Gondwana and Laurasia. And when you only have one landmass, you also, by definition, only have 1 ocean, right?

0:26:10 Eric: And that was called Panthalassa. As you can imagine, as you start getting these different oceans being separated from each other, landmasses rapidly slowly separating and forming new contours in Earth's system, that's going to have extreme effects on ocean climate, right? It's going to shift weather patterns, it's going to shift a lot of stuff, just because that energy is now being dispersed in different ways. A couple of other notes. While North America and South America are in the right spot, they're not actually connected yet. So like the Yucatan and Central America hasn't yet reached above the waters, because sea level is super high. This is a very warm period of Earth's planet. There's actually not even stable ice caps on the poles. Antarctica would actually have dinosaurs on it because it wouldn't be tropics, but you wouldn't have kind of a stable ice cap in Antarctica. You'd have the ability to live during the warm period and kind of hold out during those winter months.

0:26:09 Thomas: Wow crazy so that mean there's fossils up there sweet fossil

0:27:12 Eric: Of the best things I do with my students is when I introduce a topic like this, I asked them why there are fossil palm trees in Antarctica. That's because of plate movements, right?

0:27:22 Thomas: Palm trees know it was a dinosaur yeah crazy

0:27:25 Eric: Antarctica was in a different place a long time ago. And as they move, as the climates change, their fossil residents stay the same, even if the climate and the location of that continent changes in the present. And so you'll have tropical palm trees and Antarctica both from where it was before, but also remnants of when they could grow in that warmer time period. Okay, so it's a much warmer world. And we have a lot of the dinosaurs that we know and love, So right? Just to give kind of a quick list of some of our famous dinosaurs. We have those titanosaurs, which are like the really, truly giant sauropods. We have everyone's favorite dinosaurs, the tyrannosaurs in North and South America, kind of being that apex predator. We have the hadrosaurs, which is our duck -billed animals, right, ducky from land before time. We have ceratopsians, like triceratops, roaming around. We have our dromaeosaurs, our velociraptors, our troodontids, our deinonychus, right, those small crafty predators. We have pachycephalosaurs, the ones with those giant heads. And then in Europe and Asia, we have their equivalent of tyrannosaurs, because tyrannosaurus actually were restricted to North and South America.

0:28:37 Eric: The reason for that is before dinosaurs had a very easy time going all around the globe, right? Species in general had a much more diverse geographic footprint because of Pangea. But as our plates start shifting, they are now separated by oceans. Also had several types of birds. Right. Have the Neo Ornithines, which are the ones that are our modern birds today. But then we had all of the birds that were like Archaeopteryx, SynopteryX. Right? So we had a bunch of different type of birds at varying stages of like more dinosaur like. We also had other animals besides dinosaurs right had most of our famous sea reptiles so our mosasaurs those giant kind of whale -like looking things our elasmosaurs which is the plesiosaurs that look like the Loch and then our ichthyosaurs which are another type of archosaur another type of reptile that actually might have given birth to live young they're actually pretty fascinating which is again another example of kind of the labels we put on things are are largely not real. Now, our pterodactyls were in an interesting space because the coolest pteradactyl of all time were alive now, but they had a really sharp decrease in species diversity. The only main type of pterosaurs that were around were what we call as darkids. And as darkIDS are the really, really large ones. We're talking the size of like a jumbo jet.

0:29:58 Eric: These things would be able to fight off T -Rexes. Yeah. So Caetalcootlus was like this giant giraffe -sized thing that would would go soaring around, land on these island systems throughout Europe, chomp up animals, and then just go on its merry way to the next one in the European, kind of like an archipelago at this point because of water levels. Would have been very fun. Now, we also have a lot of our normal animals, right? We've got our crocodiles, our snakes, our anapsids, our lizards, our turtles. We have we've had mammals actually for about 100 million years at this this point, if not more. And right at the end of here is where we first start getting those marsupial and placental mammals, we've got a pretty diverse ecosystem, climate, but I should mention that dinosaur diversity in particular was in sharp decline already by this period.

0:30:16 Thomas: That sounds fun yeah dino

0:30:46 Eric: But more importantly, right, and what makes this hard to kind of disentangle when talking about the deep past, is we're seeing a lot of that anoxia in early Cretaceous rock. We're seeing volcanism from those Deccan traps in the Indian subcontinent going around for around 800 ,000 years of eruptions right around the time of the asteroid. Now, whether that happened before the asteroid, concurrent with the asteroid or caused by the asteroid, we don't quite have the resolution for in our timescale. And so it could be that this was already something that was kind of eroding away diversity in dinosaurs at the time and the the asteroid was a final push. Or it could be that this was all triggered and a byproduct of that giant impact. But dinosaurs were already in decline. At this point in terms of a diversity level, but I Wouldn't say we were in one of those extinction events, right? Those gradual, not gradual, but those relatively quick kind of loss of diversity. We're in a relatively stable decline, if that makes sense. There are a lot of theories, and this is a really cool thing. We take for granted that the asteroid is what killed the dinosaurs, right?

0:30:45 Thomas: Dei hey guess that

0:31:56 Eric: But that really wasn't the leading theory until as late as 1990. So while we kind of grew up and learned as the asteroids killing the dinosaur, that was not a foregone conclusion most of paleontology. And there were a couple of theories that I wanted to bring up very quickly. And I wanted to see, because this is the type of thing I would ask my students, if you could come up with a reason why this would not be the likely cause. So here are some of the previous theories that the dinosaurs. One was that mammals ate dinosaur eggs and they out -competed the dinosaurs, causing them to die.

0:32:28 Thomas: Sounds kind of familiar I think I I think I heard that one

0:32:32 Eric: Can you think of any reason why that would be a poor What if I told you 75 % of ocean life died off in this time period? It

0:32:42 Thomas: That would be part of it but that also just feels like like something that like I don't know if this makes any sense but I feel like that then like why it just seems like would there be some reason that that would start happening at that time versus I feellike any predator could always have that capability at any time I donno does that make sense no

0:33:03 Eric: Does and it's somewhat abutted in these theories by the idea that one thing was that dinosaurs had pretty thin eggshells and so they started hypothesizing that like maybe the eggshell were too thin and you combine that with mammals eating them and that was kind of the pushover but I would say that doesn't explain the loss of 75 of all species including mammals same another hypothesis that disease killed the dinosaurs.

0:33:29 Eric: As we know, it is very hard for disease to transfer between not only different species, but different families, different orders, right? So the idea that a virus was killing everything in the ocean and the dinosaurs is probably not likely. Another one is that new insects arose that starved out the dinosaur herbivores, crowding out the food web. That can again be disproved by the fact that we're talking talking about a global event, right? Of these theories only deal with the dinosaurs.

0:33:28 Thomas: Stds yeah yeah did these people forming these theories not have the information about the ocean stuff yet or something because it seems like those are all pretty easily disproven by the same thing.

0:34:01 Eric: They should have. Yeah, I would say they should have, and I think that this goes to a different time period in science where we were much more reductionist and not really taking everything into account. I would see science in the last 20, 30 years has moved to much more of a systems approach, especially as our computing power has gotten bigger. We're like, we don't try to reduce everything to one question and one variable, we try to really keep in mind the context of which those things develop in. Here's another fun one that can also be disproven by the ocean, but I thought was a fun note. The end of the Cretaceous is also the rise of flowers. This is when our angiosperms, our flowering plants, our grass really started to take off. And so one hypothesis was that this rapid shift in the ecosystem, again, formed a collapse of our food webs. I would say that gets disproven, sort of, yes, not only dino allergies, but let's say our herbivores can't eat those flowering plants or don't eat the flowering plant. You have emaciated triceratopsis that don't sustain the Tyrannosaurus. So they hypothesize this food web collapse, but I would that doesn't reconcile the global nature of the data. Because here's what we do see in the data, and then we will get into what actually happened. What we see is a lot of those different species, those sea reptiles, those dinosaurs, everything below this rock layer that's dated to about 66 million years ago, you then get one very thin layer of rock that is supercharged with an element called iridium, and then above that, you just have very little life, and it takes a long time for that very little little life to start to recover. Now, the iridium is actually what started to put scientists onto the asteroid as a smoking gun. Because iridium is present on Earth, but it's not super present on Earth. There's a background level of iridium that's fairly low in our soil, but you wouldn't ever expect it to get too high because it's a general kind of cycling out from the Earth's core as new rock is formed. The levels of iridium in this rock was over 25 times higher than what what they would expect to see. And that led to a couple of not even paleontologists, geophysicists who understood the significance of that iridium overload to hypothesize that it might have been an asteroid that killed the dinosaurs because that iridium was dated to around 66 million years ago. We didn't have a crater for a very, very long time, right? Actually It actually wasn't until 1990 that we found, and I'm going to apologize, the name is from a Nahuatl name, which is like the Mayan and Aztec language, so I'm going to butcher it, but the Chicxulub crater was then found off the coast of Yucatan Peninsula.

0:34:51 Thomas: Dino allergies. Now that's curious because like would there necessarily have had to been a crater? I mean is it like in that time period we sure like well you'd still see it or what if it hit like the ocean?

0:37:04 Eric: Actually hit on a very, very great point. One point is it did hit the ocean. But you are right that Earth, unlike a lot of planets and moons in our solar system, doesn't have the same kind of retention of lots of craters that most of those other things do because we have our water and wind systems, right? And so erosion is constantly working on these craters. One just happens to be so big that it's going to be fairly erosion -proof, right. This one was found underwater. Water.

0:37:33 Eric: It was found off the coast of the Yucatan Peninsula using that kind of seismic radar, right? That ground penetrating radar. Now, I'm going to give you some quick stats on the size of this crater. Crater currently is about 120 miles wide and about six miles deep.

0:37:53 Eric: It was likely caused by an asteroid that was around six to nine miles wide. Taller than Mount Everest.

0:38:02 Thomas: Massive and And with the speeds those things are doing, I mean, that's just so crazy.

0:38:05 Eric: It was traveling at 24 ,000 miles per hour in Earth's atmosphere. Hit with the force of 4.2 times 10 to the 23 joules, right? So that's 4.2, 22 zeros after it. To put it in a better perspective, that's about 1 billion Hiroshima bombs all going off instantaneously. Let's talk about what that looks like on the day the dinosaurs died. Of all, unlike most mass extinction events, this one happened very quickly. Because once that asteroid hit, we're now going to just go through what happens by those laws of physics, right? We have this Mount Everest size asteroid hitting into Earth's crust at about 24 ,000 miles an hour.

0:38:49 Thomas: Now, in the ocean or just in the Ocean? Okay. I wasn't sure if it was like later it became an ocean or something.

0:38:51 Eric: In the ocean, yes. There's both good and bad things about it hitting in the ocean. The good part is that the water can can somewhat slow as much as the ocean can slow it down, right? The problem is, is that it hit between a 45 degree and a 60 degree angle.

0:39:11 Thomas: How do they know that? Is it the crater or is it the effects?

0:39:14 Eric: Yeah, so this is actually something I've done with my students before. You can drop marbles into sand from different heights and different angles and see the shape that the crater will take as you drop it into that sand. And so based on the shape of the crater, based on kind of their projections of the way ejecta, the debris was spewed from that, they can then calculate the angle of impact. And this is one of those angle of impacts that kind of is calibrated to be as destructive as possible.

0:39:41 Eric: Because not only are you getting a near-direct hit, right? It's not a glancing blow. You're hitting it right at like that diagonal angle. You're getting just enough to get a direct hit on the force, but then you're also getting enough kind of horizontal movement to push debris all over the place.

0:39:56 Thomas: So you're telling me someone wanted to kill these dinosaurs.

0:39:59 Eric: I'm saying, well, me and my friend friend, have been working on a theory that it's actually... Yeah, we're working on it. I don't know if you watched The Expanse or read the books, but we're work on the protomolecule people based on the location of the asteroid.

0:40:01 Thomas: Sorry. So what's the motive? Yeah. Yeah. I watched the experience. Don't totally remember what that means, but sure.

0:40:17 Eric: We've got our giant Everest -sized asteroid. It's hitting the Yucatan Peninsula at about 24,000 miles an hour with the force of a hundred Hiroshima's, So right? Let's talk about what that looks like. The very first thing is an immediate kind of crater forms about that 100 miles wide, right? And the core of that crater, that immediate area, is going to get superheated by that massive kinetic energy, right. Going to reach hotter than the sun inside of that point.

0:40:23 Thomas: Crazy yeah

0:40:51 Eric: I'm sure you can imagine what that's going to do to the surrounding bedrock and the water around it.

0:40:45 Thomas: Geez yeah what happens to the impacted water does that do anything crazy or is it just like oh

0:41:00 Eric: That was the very next thing we we were getting to. Great question. So, right, if anyone's been to a pool party, you know that the bigger the person doing the cannonball, the more water gets displaced in the pool, right? We're talking about a Mount Everest-sized person doing a cannonball at 24,000 miles an hour. So not only is it splashing, it's literally displacing the ocean basin, right. Would have hundreds of miles where there is no water in that area of the ocean. It is getting displaced. Only is that that getting displaced. Earth's crust itself is getting displaced by this force.

0:41:32 Eric: The rock is getting liquefied and turned into like a puddle and pushed outward as it's just boring into the earth. The first effect is we have this massive force that's superheating that area to the heat of the sun, right? That's going to start to radiate outwards. And for about a thousand miles, everything around it is going to both get that radiation, that infrared pulse of heat, and it's going to be hit by winds at around a thousand miles an hour.

0:41:59 Eric: And that's just going to flatten, destroy everything in the area, right? We're talking sea animals being washed or strewn about hundreds of miles away on land. We are talking dinosaurs on land being completely flattened and obliterated by either the heat from this blast or the force from this last, right. Right?

0:41:59 Thomas: A lot yeah wow

0:42:20 Eric: Just thousand mile an hour winds, like 500 miles or so, like you would not want to be there in that minute, right?

0:42:19 Thomas: So so how how big is the instant death area right in that minute yeah crazy oh

0:42:32 Eric: Probably even less than that, because this infrared pulse is going to happen at the speed of light. The winds are coming at you at about a thousand miles an hour, but that infrared pulse, that initial burst of heat is going to happen very quickly.

0:42:44 Thomas: So the wind, so even if you're in the instant, oh, I would love to see like a shaded zone of like instant death 30 seconds to death you know that'd be cool I want to like the instant because the winds will get you go

0:42:53 Eric: There's a great video on YouTube by this group called Kersagot that actually does something like that. The only reason why I'm not mentioning it is because I couldn't find their sources and I just like being able to cross validate. The main point is anything in that immediate area, we're talking just instant death, right? Like you would not even realize that the asteroid hit and that you died, which is another thing I should probably bring up. When you're talking about traveling 24,000 miles an hour, we've probably all seen movies with that last scene where they're watching the meteor hit, that is not something that would happen in real life.

0:43:10 Thomas: Mm

0:43:26 Eric: That thing is traveling so fast that by the time you're seeing it in the atmosphere that morning, you are likely going to be dying once you see it enter the atmosphere. There is no time to process it. There is not time to... You're going to see it approach the atmosphere the day before, but once it enters the atmosphere, there is no like it's burning and doing that thing where like we watched that trail, it is just straight going to come for the surface.

0:43:22 Thomas: -hmm really but you are gonna see it I mean right sure yeah right yeah

0:43:53 Eric: And once it does, it has that giant pulse of heat, those thousand mile an hour winds. And then I mentioned that the crust itself is getting pushed and liquefied, right? Giant disruption of Earth's crust is going to cause everyone's favorite waves that come from the bottom of the ocean, tsunamis. And the first tsunami that it ejected out probably covered most of the globe and was like a mile high. Are talking unfathomably large waves.

0:44:22 Eric: But then all of the water that was displaced, right, to come back in and refill that area of the ocean. And that's going to be even more turbulent motion of water that's gonna cause a sustained period of tsunamis for a couple of days. And those tsunamis, while they might not be a mile high, will probably be between 450 and like 900 feet. So we're still talking Godzilla -sized waves.

0:44:45 Thomas: You're just tsunamiing for like a period of days jeez

0:44:49 Eric: Probably like the peak was like a 24 -hour period, but it was not a 24 hour period that you would want to be a part of.

0:44:54 Thomas: But like I mean uh in our day and age I mean it's a little different back then but like a 10 foot tsunami is still isn't like it doesn't have to take much to be like destructive right it's

0:45:03 Eric: For some grounding, right, those 900 foot tsunamis would be roughly like 20,000 times stronger than that tsunami that hit India in 2000, I believe, four. Which was the largest tsunami on record at the time. We've got those tsunamis, right? What also comes with disruption to earth crust and tsunamis though are giant earthquakes, right. So those earthquakes start coming in at over magnitude 11. The strongest earthquake we have on record is about 9.5. But remember that the Richter scale both generally caps at 11 and is logarithmic. Exactly. It's exponential. So, we're talking thousands of times stronger stronger in actuality because we don't even have the tools to properly measure these earthquakes. That's also going to be strong enough that it's literally shearing apart Earth's crust and making those kind of like hellish looking like random cliff form that dinosaurs would slide into in the land before time. I would actually say land before times got this largely right in terms of it just being completely, completely terrible.

0:45:34 Thomas: Exponential yeah

0:46:02 Eric: So we've got those earthquakes, we've Got those tsunamis, right? That's not even the worst part of today. The worst part today is the the gigatons worth of material

0:46:10 Thomas: Wow I said I had vacation but dinosaur vacation time booked that's the worst part of why did I wait till now to take my dino vacation occasion.

0:46:19 Eric: The worst is that gigatons, right, billions of tons of dust debris and rock are going to shoot all over the place and they're going to go many different places some of them will reach escape velocity and go into outer space right there's actually remnants of earth that have likely reached mars and the moon from this asteroid impact yeah but But most of it is going to start cycling around Earth's atmosphere, right? There's two problems with that. One is that a lot of the debris that got ejected upwards is still subject to the laws of gravity, right? And the laws OF gravity are going to bring it back down through the atmosphere. But as we know from like astronaut movies, the atmosphere and the friction that comes from reentry starts to heat up these objects, right.

0:46:22 Thomas: Gross. No, I'm just kidding. That's crazy though. Jeez.

0:47:09 Eric: You end up with gigatons worth of material being burned up in Earth's atmosphere, superheating and becoming like flaming glass shards of spears of death that rain down on these dinosaurs. And that's not only a problem for being hit with these, but if you have literally billions of tons of this, that's going to heat up the entire atmosphere. And so this part we're a little unsure of, but it might have reached a thousand degrees on Earth for one minute, it, or it might have reached like an industrial oven of like 400 degrees for a couple of hours. But there would be an intense kind of cooking of the terrestrial landscape.

0:47:46 Thomas: Long or for what distance, but

0:47:48 Eric: It's debated. It might be for one minute of like super, super intense, or like an hour or so of like just we're in an oven.

0:47:54 Thomas: Like how far would that, like how much of the earth is that?

0:47:57 Eric: This would be global.

0:47:58 Thomas: Global? Oh, wow.

0:47:58 Eric: So the dust cloud, right,

0:48:01 Thomas: Convection oven going.

0:48:01 Eric: Was so powerful that it reached around around the earth within a couple of hours.

0:48:05 Thomas: Really? So that was going to be my next question was the people, the people, the dinosaur, dinosaurs are people to me, the dinosaurs on directly the opposite side of the planet. I like want to know like how long until something came for them. But if you're telling me they got cooked, geez, a

0:48:21 Eric: They would have a couple of hours and then the hell would start, right? They'd get the earthquakes, the tsunamis, the cooking, right. Not only that, if you have a sustained period over 400 degrees, is likely to happen in all the forests on land?

0:48:37 Thomas: Delicious dinosaur pie is going to be cooked, baked. No.

0:48:41 Eric: They're going to get set on fire, right, so now you have the entire earth's plant system being set on Fire, releasing all of that.

0:48:48 Thomas: How did anything survive? I

0:48:50 Eric: So So we'll

0:48:50 Thomas: Call bullshit because nothing could have survived. This is is crazy it

0:48:52 Eric: Talk about that in about five minutes. But the real key is that pretty much everything is being cooked, right? And then it gets even worse. The type of rock that was ejected from the asteroid that was vaporized and brought into the atmosphere contained large amounts of sulfur. And this sulfur did two things.

0:49:08 Thomas: Smelled bad they're like ah just me already this stinks a

0:49:13 Eric: Is kind of like an anti -greenhouse gas. It gets stuck in the atmosphere and starts blocking the sun and helps seed in cloud formation with all those dusts. It also causes rain to fall to be more acidic than normal. We just had this period of intense cooking, right? Earthquakes, tsunamis, right, those first couple of days is a hellscape. Then for the next two or three years, you are living on a dust snow globe, right where where the dusk kind of crowds out the sun and makes it so that you can't get any photosynthesis and any heat reaching the atmosphere. Earth's temperature is going to plummet up to eight degrees during this time period, Which right? Is really, really drastic. But more importantly, there's not going to be photosynthesis. So without that photosynthesis, all of the plankton in the ocean can't survive. And the plankton start to collapse. And once you get plankton collapsing in the Ocean, you start to lose pretty much the rest of your ecosystem. And

0:49:40 Thomas: Dust snow globe yeah I'm calling bullshit on anything surviving no way sorry didn't happen yeah

0:50:17 Eric: Have I painted a drastic enough picture yet.

0:50:19 Thomas: That's the whole earth died but you're gonna tell me some little mouse in a cave somehow I call bullshit there's no way

0:50:23 Eric: And I do think it's important that we kind of talk about what we mean by things did okay, right? Because roughly 70 % of all life on earth died. But I think there's this misnomer that like mammals were uniquely suited for this event, right? And that like, birds were suited for THIS event. And there really was nothing that was suited for This event. This is not an event that you are suited for. Even mammals, even birds, even the animals that did survive did not survive unscathed, right? Lost a lot of their diversity during this time period because without photosynthesis, you're going to collapse those food lobes. Let's talk about some of the things that would survive and why some of those birds survived, right. We lost every bird that wasn't the modern bird, the neo -ornithine. We lost most of our mammals and they had to re -radiate out. But the things that did survive were generally falling into two categories. They were generalists. They like eating lots of different stuff, right? Think about our ancient mouse -like ancestors. They're going to survive on plants, dead things, nuts, seeds, insects, anything they can get their hand on. And many species of birds are the same way, right. They have a very adaptable diet. Also generally lived in burrows. Birds at this point even the dominant bird species And there were lots of other things in the sky. So they were largely pushed into like a more burrowing habitat, at least the ones that survived were.

0:50:34 Thomas: I wouldn't think so how far can can they burrow 500 meters like I don't understand huh

0:51:57 Eric: You wouldn't have to burrow as far as you think. The ground is pretty good at holding its temperature and being a nerve from surface kind of events. And a good way to always visualize this is air conducts heat way more rapidly than ground in water. And the way you know this, right, is when you stick your hand above a boiling pot of water, you don't feel the heat from that water. When you Stick your hand in an oven, you feel that heat immediately. Animals that were able to find shelter in water or the ground had a much higher chance of surviving, especially ones that could then eat whatever was left over. Freshwater systems in particular, there

0:52:34 Thomas: But there are like no plants I don't get it how did that not yeah

0:52:39 Eric: Weren't plants for a while, but those plants have to die, right? So for at least a while you have some dead matter, but then also if you're a vulture, you don't care that there's no plants, you're living your best life in this time period. You have nothing but food,

0:52:54 Thomas: For a little while but then that like that doesn't they don't have refrigeration yeah

0:52:58 Eric: Well, keep in mind, not everything probably died at once. You're still probably getting a steady stream of death over these two or three years as the ecosystem system collapses, right? Also, if you're like a snake or turtle or crocodile that survived, chances are you were living either if you're a snake, or a turtle in a burrow. But if you're crocodile, the way you survived is a lot of crocodiles are freshwater animals. And freshwater animals have a huge advantage in these types of extinction events. That's both because they live in water that can be protected like the giant atmosphere cooking event. But but they're also not connected to the oceans as much. So you don't have a lot of those environmental effects. And then it gets even better in that in a lot of freshwater ecosystems, plants actually aren't the main source of that bottom of the food web. You actually have a lot of what we call detritivores, things that do eat dead things. And so if you're an ecosystem that has the base of its ecosystem as dead things, you're going to do much better than other things in

0:53:58 Thomas: That basically anything with a jordan peterson diet did great but but lydia and I as dinosaurs would be like well that's the end of me crazy

0:54:06 Eric: But that's basically the story of the dinosaurs is what really happened is a billion nuclear bombs went off at once, literally cooked the earth to a point of it literally being on fire. And then it rapidly cooled into a post -apocalyptic nuclear winter. And that one -two punch is just devastating. So in the aftermath, we have 75% of all life. Again, we Have those generalists, those burrs and their freshwaters that have a kind of increased survivability, but they did not survive unscathed. What they were, were the animals that set the new world order of the Cenozoic, right? Most of the major animal groups that we have got their start from being the kind of lone survivors that then radiated it out from that extinction event.

0:54:23 Thomas: Man great the jordan pederson animals set the new world order no No wonder everything sucks.

0:54:54 Eric: Now, I've got two quick codas to end on. This was actually only the second largest asteroid that ever hit the earth. Yes. There was one about twice as large, not the one that made the moon. That was actually a rogue exoplanet that ran into earth, but an asteroid that was two times the size of the one, that killed the dinosaurs.

0:55:05 Thomas: The one that made the moon? Oh, jeez. Your doors, everyone. There's rogue exoplanets.

0:55:20 Eric: Two times. There's a reason we don't talk about it though.

0:55:19 Thomas: Two? No way. Because it

0:55:24 Eric: If we're talking 2 billion years ago, the only thing that it could have affected were bacteria and we don't really care about bacteria it was a little bit of a tree falling in the forest the bacteria hard to extinct bacteria you can kill individual ones but they can form spores that basically let them survive in outer space one of my favorite hypotheses for life on earth I don't think it's true but one of My favorite hypotheses is that life on Earth actually came from life on Mars Mars had an extinction event similar to the one that killed the dinosaurs. And as that asteroid hit, it ejected out bacteria in rocks onto planet Earth and seeded Earth with

0:55:24 Thomas: Happened. We know that, like, it is interesting that bacteria survived, though. Because sounds so insane. Yeah. Yeah.

0:56:07 Eric: Life.

0:56:08 Thomas: It would just, you know, extend the question again, like where did that come from? But, yeah. Is cool.

0:56:14 Eric: Side note, there's actually liquid water on Mars beneath the surface in a recent discovery. So it's possible we seeded Mars with microbial life from the Cretaceous period. And then the last thing that I want to kind of end on is just a quick warning. Was the last major extinction event until today. Mass extinction event. And this one is entirely caused by humans. And it's the same causes that we've been talking about through this entire episode. Anoxia and acidification of the oceans, warming and disruption of the balance between oxygen and carbon dioxide in our atmosphere, displacement and movement of ecosystems into places that were previously separated, now becoming joined together, right? All of these things that we are doing are mimicking the effects of previous mass extinctions. The only thing we're not doing is the one from the Cretaceous that killed everything in

0:56:32 Thomas: Today, yeah,

0:57:08 Eric: A day. Well,

0:57:08 Thomas: We haven't, so far we haven'T made our own asteroid to hit ourselves with, but you know, it's not out of the question at this point.

0:57:14 Eric: To be honest, we actually have, right? I describe this as hitting with the force of a billion nuclear bombs. We don't have a billion nuclear bonds, but we probably have enough to form a mass extinction event in a single bad day. Because no matter what, we would get that nuclear winter where all that debris then settles into the atmosphere and then crowds out the sun.

0:57:34 Thomas: About that recent headline? What was that?

0:57:37 Eric: Right. Sorry. Yes. Just yesterday, or two days ago, I think, there was a new discovery about the asteroid. And this one is more of a curiosity than like a real important addition to the story. What they did was they did a chemical analysis of samples from the crater, right? And what they found was that there was an enrichment of this element called ruthenium. And the reason why that's important is it's kind of like when you have wine experts going like, you can tell by the notes of blackberries that this was grown in the Alsace region in France, right? What they're doing is they're using the chemical makeup of those samples to kind of fingerprint both what the asteroid is made of and where it came from. And where it came from was an outer part of the asteroid belt beyond the orbit of Jupiter, which actually makes it kind of interesting. Because one of the reasons why asteroid impacts are relatively rare on Earth

0:58:27 Thomas: It was because Jupiter eats them up, gobbles them up for us. It's

0:58:30 Eric: Is because Jupiter helps gobble them up. But every once in a while it works the opposite way and its massive gravity kicks a stable orbit into us. And that was the other thing I wanted to mention. There's also a reason why asteroids were much more common in the early, early parts of Earth's history and much less common now. Right. Start to fall into stable orbits and anything that would have easily hit Earth has already hit Earth. So there's a somewhat depletion. Now, there will be new asteroids that get kicked out of orbit because of stochastic stuff. But the planetary orbits and solar system was just much less stable for know, four to three billion years ago. So you had much more things that were loose and moving around in non -stable orbits. And as that calmed down, Earth finally got to get life going, which also is a real cool story about the history of life. Really, as soon as Earth stopped getting constantly pelted by asteroids and calmed down for like a couple hundred million years, we got bacteria.

0:59:28 Thomas: Like all right if you stop pelting me I'll make life give me a second yeah

0:59:33 Eric: Why I think we vastly underestimate the kind for life to form in the universe, right? Is made of four of the most common elements, and it's just simple laws of physics. If it can happen here, it should be able to happen anywhere where you have similar conditions.

0:59:47 Thomas: To be fair though there may also be a lot of impacts other places so maybe that's a common thing I don't know yeah

0:59:52 Eric: But this is kind of like the good get out of jail free about space is it's so astronomically big that you can lose 99.99% of all possible habitable Earths to like other caveats and conditions, and you're still left with millions and millions of planets that can support life. Well,

1:00:11 Thomas: But nothing anywhere near us unfortunately but yeah so this was awesome um one out for the dinosaurs everyone rest in peace yeah

1:00:18 Eric: The non -avian dinosaurs, because of course we do still have some dinosaurs flying around every day.

1:00:20 Thomas: I if any of them remember that no that That doesn't make sense. All right. Well, this was so much fun. Every bit as fun as advertised. Thank you so much, Eric. Good luck with the new school year. I hope you can still squeeze in a dino recording here and there.

1:00:37 Eric: Me up and I will try to find ways to make it work because I really do enjoy coming on and I just love talking science.

1:00:42 Thomas: You send people anywhere? I forget. Do

1:00:44 Eric: Do not, but I say currently support education and support candidates that support education.

1:00:51 Thomas: No idea which candidates those would be.

1:00:55 Eric: And that's why I'm formally endorsing Donald Trump for president. Please cut that.

1:01:00 Thomas: Yeah. You and AI Taylor Swift.

1:01:02 Eric: It's just I heard brett wine scene again and he just started making a lot more sense anytime

1:01:06 Thomas: All right, thanks so much. Thank you very much.

1:01:26 Eric: Bucky you gotta chill buddy. Nope we're not doing that right now. Sorry he is nine months old and he has a mind of his own. Buffy uh

1:01:35 Thomas: It sounded like that's how he communicates It's like, yeah, you're telling me someone wanted to kill these dinosaurs.

1:01:42 Eric: Would actually say land before times got this largely right in terms