What if the asteroid hadn't killed the dinosaurs?

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Speaker 1: Hey, Jorge, what did you want for your birthday when you were nine? I'm pretty sure I wanted legos because I think throughout most of my childhood that's all I wanted. What do I do? Yeah? Probably legos? That or having my own bedroom. Did you want legos so you could build your own room. I wanted my own room so I didn't have to share my legos? Oh? So are you saying that nine year old Jorge didn't want answers to some big science questions. I think Jorge in the third grade didn't know what science was, So probably my biggest science question would be what is science? So you weren't wondering about aliens and black holes? I did probably have a question about the universe back then? What was that? Well, what's the biggest thing you can build out of legos? All right, I'm going online after this to buy you a bunch of legos. Done, I'll take it. It's on the record. You know my address. Did they make a entire universe set for legos? I'm thinking of adding to our house, so I think we'll we'll just make it out of legos. Did you send me save on constructor materials? Hi'm r Hammack, cartoonists and the creator of PhD Comics. Hi, I'm Daniel. I'm a particle physicist, and I'm not great at building real things out of legos. Really, you never play with them as a kid. No, I play with legos all the time, but I always end up making weird abstract stuff rather than like ships or dinosaurs or you know, cartoon characters. I would have thought as a future particle physicist, all you would do is build stuff and then smashing together. Is there another reason to make legos? Then knocking them down? That is the joyful part. Now, the joys putting them together, right, seeing how everything fits together, that's part of the wonder Well, there is a wonderful connection between legos and particle physics because it turns out that our universe follows the lego principle. It's made of tiny, little interlocking pieces, and everything that's unique about you is how those pieces are put together, not the pieces themselves. Are quarks also painful when you step on them, by excellent absolutely, since legos are made out of quarks, it's really the quarks that you're stepping on at three in the morning. But welcome to our podcast. Daniel and Jorge explain the university production of I Heart Radio, in which we knock down everything about the universe and break it up in the tiny, little lego sized pieces so that we can explain it to you. We tackle black holes and neutron stars and galaxies and the tiniest of little particles. We tear all of it apart and show you what it's made out of, the pieces that we understand and the pieces that we are still puzzling over. Yeah, because it is a pretty wonderful universe, very complex, very interesting, very fascinating to see how it all sort of fits together, because it does seem like sometimes somebody put it together using some kind of instruction manual. It does sometimes, and it makes me wonder if we ever do figure out what the smallest thing is, what that will sort of mean, you know, what we will learn from that philosophically, how we will interpret that if the universe is made out of strings or tiny little foaming bits of space or something else entirely, Eventually we'll be faced with the question, what does that mean about the universe? Yeah, because there might be a tiny little particle at the end of everything that everything is made out of and Daniel, I think if you ever discovered I think you should call it with some sort of acronym that spells out lego, because that would be just so wonderfully ironic, maybe like light energetic gluon ob oreo oreo. You can't call a particle an oreo because oreos have something inside them, so it can't be fundamental. Oh boy, you can go in loops like maybe oreos are then made out of legos, and legos are made out of oreosa. Our oreos and acronym. I just wonder because I always see them capitalized. Hey, you're right, Yeah, what does oreo stand for? Another secret of the universe uncovered here? Yeah, listeners out there educated us what does oreo mean? But it is a wonderful universe, and you know, as human beings, we sort of can't help as we look at it. We can't help but wonder about it and ask questions about it. You know, we see things that we don't understand, or see things that are maybe seem unexplainable, and you have to ask, why is it the way that is or how does that work? Yeah, and we are surfing along on this incredible wave of scientific knowledge. People a hundred years ago do so much less about the universe than we do, and people in a hundred years will know exponentially more about the universe than we do. So every year that goes by, we gain more and more insight into this crazy, bonkers universe. And all you have to do is sit back and enjoy the wave, or you can come join us and pitch in to create that knowledge. Yeah, there's a lot we know and a lot we don't know, and people have questions. And by the way, I should give a shout out again to our book. Frequently ask questions about the universe, which is out down people can get it, and we answer all kinds of amazing questions in it for you. That's right, And for those moments on our podcast when we're he says, Oh, that's tricky to do on a podcast. I wish I could scribble on a piece of paper. Well, the book is a bunch of pieces of paper. A lot of them have Jorges hilarious scribbles on them. Because don't forget he's not just a podcaster. He's also a cartoonist. Just a cartoonists, yes, but yeah, we askewer all kinds of awesome questions in it, So please support the podcast. Get a book for yourself when you read over the holidays, or for a friend, or maybe as a leg gift to that special love when you totally forgot about. Or if you're building an extension to your house and you need some building materials, order a bunch of copies. Yeah, they staged pretty well, right, the rectangular they're sort of brick like they're made out of dance matter as well, that's right. But yeah, people have questions, and we get so many questions on the podcast here through social media that we couldn't fit them all in one book, and so we like to answer those questions here on the podcast live. That's right. We encourage you when you are thinking about the universe and wondering how something works to write to us two questions at Daniel and Jorge dot com. I can usually answer people's emails in less than a day and give them a clear answer about their question. Sometimes the question is so good that I want to talk about it on the podcast. When we ask listeners to send in audio of themselves asking their question. Yeah, so to be on the program will be tackling listener questions. Number twenty two twenty two. Have we actually recorded twenty two of these listener question episodes? We have in our more than three hundred fifty episodes that we've done so far, we've done twenty two listener question episodes, which means we've answered like sixty six questions on the air. Wow. And the questions keep on coming, right. They come into your inbox every day. Absolutely, we get dozens of questions every single day, and they're a joy to read because it shows me that people out there are thinking. They're using physics to try to understand the universe. They're taking the ideas we are giving them and trying to apply them elsewhere and saying, hey, how come this doesn't work? Or I don't get it? What happens when the ship turns around in the twin paradox. So if you're confused about something or you see something in physics you don't understand, please don't be shy right to us. Two questions at Daniel and Jorge dot com. We love your emails. Do you ever get questions about legos? Which color should I use? Next door? Have you seen my four by one piece? Have you seen my lego model of the fundamental particle of the universe. No, but I think we should have a contest. We should have listeners send in pictures of their most physics Lego creations. Interesting, So email those to us two questions at Daniel and Jorge dot com, and we'll post our favorites online. And you can't just have like one little piece in the middle there and say it's like a model the fundamental particle of nature. That's that's right, or just a black picture and say hey it's a black hole. Yeah, it's a dark matter. That's an empty picture, and then and just say it's dark matter, lego, that's right. In this episode is airing just after Christmas, so I hope that all of you folks out there have been lucky and gotten some nice pile of new Legos for Christmas and can make something physics see out of it and send us a nice snapshot. Yeah. So we'll be answering questions from listeners here today, and we have some awesome questions about asteroids and dinosaurs and black holes, the cane stars and and that's all just one question or maybe two questions, and also aliens of course, what's happening in proximusentri So these are awesome questions, and we'll start for this first one from Spencer from Melbourne, who, by the way, is having a birthday right now. That's right, December twenty ninth is Spencer's birthday, So happy birthday, Spencer. He's in Melbourne, Australia. But does that mean that if it's decembery here, it's actually already December twenty nine in Australia. Yeah, but three years in the future, because those Australians are ahead of their time. That's right through the wormhole. We are also communicating with Spencer's and seventy five birthday parties. Yeah, well we should record his next like three birthdays here right now so you can just replay them. So happy ninth birthday, Spencer, and happy tenth birthday, Spencer. And happy eleventh birthday that's right, and happy seventy fifth birthday. I hope we're all still around by Yeah. I doubt it though, unless we moved to Australia and they have that fasting technology. That's right, Australia is going to deflect the asteroid, but only from Australia. They're gonna send it our way instead. Yeah, but happy birthday, Spencer, and thank you for listening to the podcast. We hear you're a big fan and we have your question here that's really awesome and it's about asteroids and dinosaurs. Hi, Daniel and j Hi. My name is Spencer. I live in Australia and um eight years old. So I have this questions for you. So, um, what would happen if the asteroid that killed the Donna Shaws missed us? And I really love your podcast and I can't waite to hear your answer. Oh so awesome. Thank you Spencer. That's such a great question. I feel like that's a plot of a movie, the voice of a future scientist, I love it, or a science fiction author. Yeah maybe, Yeah, I think there's a job for you at Marvel. They have a whole show called What If Agents. Somebody get out there and get Spencer on contract. Well, it's a great question, and his question is what would happen if the aster right that killed the dinosaurs had actually missed the Earth? That's a pretty big one, right, like would we still be around? Even? It's a wonderful idea to think about because it really shows you how our existence depends on a huge sequence of random events. Things that might have gone slightly differently and could have had very very different outcomes. It's really amazingly improbable that we are even here. Yeah, it's sort of a crazy coincidence that we're all here right now the way we are right now. Like any sort of small event in the past could have changed the course of history or even the course of your life exactly. And you might imagine that, you know, things would have roughly gone the same way. But there are moments in evolution of life and in our cosmic history when very small changes would lead to very large differences in the outcome. And this is a great example, because for that asteroid to hit the Earth, it had to be on exactly the right trajectory, a tiny little deviation earlier on like a hundred or a thousand years earlier in its history, and it would have missed the Earth, and the Earth could have had a totally different history. So like some little rock bouncing against that asteroid a thousand years before it hit totally determined the future of life on Earth. Yeah, all right, Well, let's get to answering Spencer's question. And I guess, first of all, Daniel, an asteroid killed the dinosaurs. That's the prevailing theory these days, we think that a piece of rock from the outer part of the asteroid belt, something about the size of Mount Everest, hit the Earth around sixty five million years ago, traveling around thirty kilometers per second. So that's an incredible amount of energy to deliver to the surface of the Earth. Thirty kilometers per second. That's faster than the speed of sound, right, that's that's super fast. It's super fast, and it would have caused incredible shock waves. And you know, rocks are hitting the atmosphere all the time. Every time you see a shooting star, that's a rock hitting the atmosphere. But the atmosphere slows them down and there's friction, and that's where they heat up and they burn and they turn into flames. And a huge number of them never hit the ground because they melt. They vaporized before they hit the ground. But if you're big enough to serve that, only your outer edges vaporized and the core actually hits the surface of the Earth. And this one was definitely plenty big to hit the surface and cause a huge amount of damage. Yeah, it came with a ton of energy. I mean, like much much bigger than the Hiroshima bomb or any of those nuclear bombs we have yet. It has the energy equivalent of ten billion Hiroshima bombs. So it was an enormous, devastating impact and delivered an incredible amount of energy to the atmosphere and also to the surface of the Earth itself. Yeah, and it hits somewhere in the Yucatan Peninsula, right, which is in Mexico. Yeah, it hit in the Yucatan, which is really interesting and had a big role in its effect on life on Earth because the water there is fairly shallow. If it had hit a few minutes earlier or a few minutes later, like if it had gone deep into the Atlantic or deep into the Pacific, it would have had a very different effect on life on Earth. So it hit fairly shallow, which means it didn't throw up like a huge amount of water, just like a maybe a hundred meter high tsunami. It's just pretty small for such a big impact. But it did throw up a lot of sulfur into the atmosphere because the rocks right there, it's a carbon layer with a lot of sulfur, So it threw up a huge amount of sulfur into the atmosphere, which caused a lot of problems for life on Earth. I guess maybe a basic question is, like how do we know these things? I know that you can see the creator there and that you cannot peninsula, but how do we know like that's the creator that the asteroid that killed the dinosaurs landed in. You know, like, how do we know that's the one? And how do we know you know, when it hit and and how big it was. These are great questions, and it's been a while. It's been taken like decades to really put the story together. It's always going to be a little bit circumstantial. But you know, we know that there was a die off around sixty five million years ago. When you look at the fossil record, seventy of all species when extinct around sixty five million years ago, so clearly something happened. And then we also see evidence for this impact, which we can date to the same time using you know, geological layers. We can see time pass as you dig down deeper into the earth, and we see this creater and it's not just like a big hole in the ground. It looks like a crazy impact, like there are rocks that only form uncertain circumstances like incredible high energy events. This thing called shocked quartz, for example, only happens when there's a huge impact, and so there's a layer there that is evidence of an enormous impact right around the same time. How interesting, when the asteroids hit the Earth, it actually kind of transforms some of the rock that was there, or part of the rock that came with the asteroid, like made new kinds of rock. Yeah, rocks that you only see under like devastating impacts. And so it's a pretty clear signature that there was a devastating impact right around the same time as a huge die off. We can time these things pretty well, but it's sixty five million years in the past, and so you know, the uncertainty of these things is like a few thousand years by now, which seems small compared to you know, millions of years, but it's still pretty big. So we're pretty sure that these two things are aligned, but you know, we never know for sure in science, right six is five minut in years is a long time, And I guess the other question is how do we know that that it passed by the Earth once before? Like that's the part of the theories that this asteroid actually sort of did a drive by before it hit the Earth, like it was checking us out. Maybe. Yeah. When we went to JPL to talk to the team there that watches asteroids constantly to make sure this is not about to happen to us, they told us that that's the theory, that this asteroid didn't just like come straight out of the asteroid belt and hit the Earth. You know, it does a bunch of orbits before it actually hits the Earth. And in one of their reconstructions, they think that it made a really near miss one time when it run around the Sun and then it looped around again and came back and hit the Earth, which means that if you had looked up in the sky as a dinosaur, you might have seen it. And if you had been like a dinosaur scientist, you might have had some like years warning, which means, you know, you could have done something. So this comes from, you know, it's a little bit speculative, but they have an idea for where it came from in the outer asteroid belt and how big it was and where it hit and its velocity, so they can sort of like backtrack its trajectory. And this is one of those possible scenarios. Yeah, I bet they did see it, and I bet the conversation when some something like meaning like I have these little hands in front of me, I can't do anything with them set the t rex. Yeah, they didn't really have like dexterous fingers which allowed them to develop technology and send emails to get stuff done, because we all know that's how you get stuff done in this world is sending email and that's why. Anyways, so Spencer's question. Back to Spencer's question, his question was what if that asteroid had not hit the Earth? Like, what if it had missed us? What would have happened to Earth? To the history of Earth. I guess, first of all, with that rock, do you think would still be flying around? And would it sort of eventually hit us? Oh? Yeah, that's a fun question. What if it hit us later on? Right? I think the Spencer's question is like what if it missed entirely? If that hadn't happened, what would be the future of Earth? But you can imagine also it's of different scenarios where you know, waits a few more years or a few more thousands of years and then hits us and probably has similar impacts. It's really fun to think about, and I like to think about not just whether it hit the Earth, but like if it had hit the Earth in a different place. Because when it hit in the Yucatan, it threw up all this sulfur into the atmosphere, which caused incredible dust and acid rain. They were like shock waves magnitude twelve, earthquakes and volcanoes triggered. And it would have been different if it had hit the Pacific, for example, because that would have absorbed a lot more energy and you would have gotten more tsunamis and fewer earthquakes. For example, you've gotten like a five kilometer high tsunami, which would have been pretty amazing. Yeah, like a five kilometer a tall wave of coming at you that would have probably taken out most vegetation and animals in most coasts around the world. Yeah, So people speculated that maybe larger dinosaurs would have survived if it had hit in the Pacific or in the Atlantic. But because it hit in the Yucatan and threw up all this like burning ejecta into the sky that started wildfires and everything all over the Earth, that it spelled in media doom for those guys. But let's talk about what it would have happened if it had missed entirely. And this is a really active area of discussion among evolutionary biologists because some of them think that the dinosaurs were sort of already on their way out, that the climate was cooling and the dinosaurs were not well adapted, and so some scientists argue that at the end of the Cretaceous, the dinosaurs had been declining already for forty million years and that mammals were on the ascendants. Interesting, so like maybe dinosaurs were about to be extinct anyways, or at least the larger ones, right, Is that what you mean by dinosaurs or do you mean like all dinosaurs? No, I mean just the large ones, because you know, dinosaurs technically not extinct. Birds are descendants of dinosaurs, so all the birds out there are dinosaurs. So we're really just talking about the large non avian dinosaurs, right right, the cool ones, big ones with big teeth and horns. This is sort of like you know, your TV show quits before it gets canceled, you know, by the network or something. So it might be that the dinosaurs were sort of on the way out, that the t rex is and the Bronchosaurus is and all those guys. We're not going to last until present day, right, But is there something about dinosaurs and wouldn't have survived the change in climate? Like is it just not sustainable to be that big? Is that what you mean? I think it's more a question of competition. You know, are the dinosaurs or were the mammals better adapted to the climate as it was cooling. And there's one scientist, Mike Benton, a paleontologist at Bristol University, who argues that there's evidence that mammals were really rapidly diversifying just before this happened, and so they were sort of poised to fill a lot more niches than the dinosaurs. So it's really all about competition. But most evolution of biologists, I think disagree and argue that dinosaurs are very, very adaptable and then no matter what would have happened to the climate, they would have found a way to survive. I mean, one piece of evidence for that is that there are still twice as many species of birds as there are mammals today. So dinosaurs, including birds and their ancestors, were very, very adaptable, and then those survived the asteroid, right, Like, something about that asteroid killed those big dinosaurs was maybe like a sped up version of what was going to happen anyways over millions of years. It could be. But if it happened more slowly, then those bigger dinosaurs could have potentially survived, though they would be changed. So if the asteroid hadn't hit the Earth and t rexes and all those guys had survived, we wouldn't see t rex is walking around today looking the way the fossil reconstruction does. The same way. There's lots of animals from the past that we don't see walking around today because they're extinct or because they have adapted. You know, horses don't look anything like they used to, for example, right, Yeah, maybe like there would be small t rexes running around or small you know, pterodactyls flying around, like small versions of them. Yeah, And so people have gone back and looked at like the history of the Earth's climate and thought about how that might have affected the dinosaurs. If the asteroid hadn't hit so fifty five million years ago, for example, things got really really hot. You got eight degrees celsie is hotter than it was today, and there were rainforests spanning much of the planet, so dinosaurs would have to adapt it to that. And then thirty five million years ago, things got colder and draw fire, and instead of rainforest, you had grasslands covering most of the earth, and that's why we have things like elk and deer and all sorts of fast four footed mammals evolved. So you know, dinosaurs would have had to adapt it to all of those and we might have had very different, very interesting new kinds of dinosaurs evolved in response to these climate changes. Interesting, so they would have stuck around and they would have adapted and evolved, and I think it's sort of inevitably maybe had a showdown with mammals, right, Like, that's sort of like maybe more of a direct competition with mammals, maybe a big dinosaur mammal war. Now you're writing your screenplay, I can hear it. Something that's really interesting that I didn't realize is that dinosaurs weren't around to see flowers. Like flowering plants evolved after dinosaurs, and flowering plants are easier to survive on because there's like a dense packet of nutrition there either in the fruits or in the seeds or whatever. So dinosaurs might have evolved in response to that. They could have been smaller, for example, they wouldn't have to be so big, and that's one reason that our ancestors survived. You know, they were like swinging in the trees, eating fruits, and so it's interesting to wonder like, would dinosaur have evolved to fill that niche, you know, like the dinosaur version of a monkey. What would that have looked like? Would they have been competition with you know, our ancestors. It's fascinating. Yeah, yeah, all right, let's talk about a little bit about what that might mean for humans, and let's answer other questions from listeners. But first let's take a quick break. All right, we are answering listening to questions, and our first one was about dinosaurs and what would have happened if the asteroid that killed them had actually missed the earth, and we talked about how they would have adapted maybe and lived with mammals. But do you think, Daniel, that that wouldn't have meant no humans or do you think humans might have still evolved with dinosaurs. It's really hard to say, because there are no evidence of dinosaurs living in the evolutionary niche that humans take, you know, or that our ancestors took, sort of like living in trees, eating fruits, swinging around. There really aren't any dinosaurs, but then again, they weren't around when fruits and flowering plants evolved, so who knows how they would have responded or if they would have figured that out. Are you saying the humans evolved intelligence because they could eat bananas despite eating bananas? Well, that's a competing theory. I have my own theory about human evolution here. But yeah, it takes like a lot of dexterity to climb trees and to swing around them, and that gives you dexterous fingers, which allows you to manipulate your environment and develop tools and do all sorts of crazy things dot dot dot intelligence. Right, So I'm not saying bananas are responsible for physics. Bananas are tricky to peel. I mean not everyone can peel them easily. Yeah, but do all animals actually peel them? When they do, they just chop down beneath the skin. Also, well, the only intelligent once peel, which is what I'm saying. I see, that's the intelligence us, right, there. But I guess another cool scenarios that dinosaurs could have evolved intelligence and maybe they would have been like the primary species on Earth and developed spaceships and internet and phones. It's one of those deep questions what forms can intelligence take and what makes it evolve? Something we see about life on Earth is that life on Earth started fairly shortly after it was possible, like life has been around a long long time. Once the earth cooled and the chemistry was around, it didn't take that long for life to kick off, but it did take billions of years for intelligence to evolve, which might suggest that it's rare or difficult or unlikely. But you know, we're extrapolating from one example, so we don't know if another species might have developed intelligence, or if it would have taken another billion years for dinosaurs to become intelligent, or you know, maybe something else would have happened. Another afteroid would have come and killed everybody, and then the slugs would have become intelligent. Who knows, and everything would have been a lot slower. That sounds great, Actually, I bet slugs don't send him an emails. I bet they just sit in the couch all day. Into physics all right, well, thank you Spencer for that awesome question, that big what if question? And again, happy birthday. So we'll get to our next question here, and this one is from Corin, who is eleven years old. Hy Daniel Joy. My name is Julian love the show. Thank you so much for making it. Um. My son Corne recently asked me a question that I did not know how to answer, so I was really hoping you could help. How do we know that black holes come from the Kyne Star? Awesome question? Thank you Corne and Dad. That's so great. Did you guys listen to the podcast together? That is wonderful. I really enjoy hearing people out there supporting the next generation of curious scientists. So thank you all your parents and teachers of course for encouraging thinkers of the next generation. Yeah, so this one is a pretty tricky question and it's a little bit technical, but Corn wants to know how do we know that black holes come from the Kayne Stars? Like, you know, we black holes are so mysterious, we barely have a picture of them. They were mostly theoretical for a long time, Like how do we know their origin and how do we know where they come? From It's a great question, and it's important to think about what we do know and how we've drawn these conclusions, because sometimes we led astray. Sometimes we don't actually have evidence for something, we assume it's true, and then we discover, oh, that was a big mistake. It turns out that the universe works in a totally different way. So it's really good idea to go back and examine what we do know and how we know it. And it's especially tricky to understand how things in the universe turn into other things because it usually takes a long time. It might take a million years or a billion years for a start to burn out. So how do you learn about how this thing happens. You don't have a billion years to watch something, right, You can't just watch a star for a billion years until it turns into a black hole. It's pretty tricky to figure this stuff out. There would be a long PhD. I mean, that would take you billion years just to get that degree. But we do have another tool, which is that we can look out into the universe, and we can look further and further out, which means we're looking further and further back in time. Because remember light travels at a finite though dizzy lee fast speed, and that means that as we look further out into the universe, we're looking further back in time. So we can sort of like rewind and fast forward movies of the universe to see what happened. You can never look at one object at different slices in time, but you can look at different populations and you can see how things on average evolve. Right. It's like you can see a whole group of people are a little town of people, and you can see, oh, there are babies, and then there are also a little slightly bigger humans, and then slightly bigger humans, and then there's humans again wrinkles and seem to get old. And then so you sort of piece it together and say, okay, I think these humans go from babies to old people exactly. And we can't follow one individual person in that analogy through their whole life, but we can sort of piece that story together by seeing different slices from sort of different villages, and that story tells us that there is this evolution of stars, that stars are formed, we see that, and that they burn for a long time, that they expand, and that they collapse and sometimes make supernova and all those things we see again, not from an individual star, but we can see different stars at various points in their evolution. And sometimes we look at what happens after a supernova and we see this incredible cloud of stuff, this rememnants of the supernova blowing out most of its contents. But at the heart you can see something dark and something massive right there where the star used to be. Right, And I think we've actually seen sort of seem supernovas right like throughout our history. We've sort of seen a few of them and also at least see them as just as after they happen. Yes, we can see supernova happen. It's incredible because they're very short lived, right, They burn like brighter than the entire galaxy that they're in, and sometimes they last a few days, sometimes a few weeks, but there are these very brief moments in time. Then, of course we can't wait around for the black hole to form or to show it's as evidence, but we can look somewhere else from the universe, somewhere where we think a supernova happened recently, and we can tell a supernova happened because we see, for example, these clouds of gas and dust shooting out from the center at very high speeds, which is the kind of thing that only happens in a supernova. So we see, oh, here's the supernova that happened a thousand years ago or a million years ago, And we can look at the heart of that and ask, is there a black hole right there at the heart of this cloud that came from a dying star? Yeah, and sometimes you can see it, right, I mean you don't see it directly, you don't see the black hole and like a picture of it, but you see it kind of tugging on the things around it, but without any sort of bright light coming from it exactly. And we did actually once recently see a black hole that had just been born. There's this supernova called a T two thousand eighteen c o W, which is known to astronomers as the cow. Is that like the goat, but different accomplishment level? That's right, there's a different acronym there for cow. And this was very dark at the center and then suddenly it became very very bright. So this is like a supernova remnant, and at the heart of it was dark and then all of a sudden it turned on and was very very bright. And that's actually counterintuitively evidence for a black hole, because what happens in a black hole is that while it itself doesn't give off light, the gas and the dust swirling around it and the accretion disk get very very hot and they can admit a lot of radiation, very very bright sources of X rays, for example. And so what they saw, they think, is this black hole sort of turning on and giving off these beams of X rays from a secretion disk. So that's a pretty good evidence of seeing a black hole form after the death of a star. Wow, so you can actually we've actually seen this baby black hole and saw that it came from a star that imploded. Yeah, and it makes sense because if you keep looking around long enough, you should capture a star basically every stage of its life cycle. And so if you look at enough stars, you'll see these things. For me, you'll see black holes. For me, you'll see supernovas at all different stages. It really pretty fun. And on top of that experimental evidence, you know, seeing all these things at different stages, we also have a model. We have a theory for how stars form, and we can do this in simulation, we can say we know what the laws of physics are. We think we understand the starting point for stars, what should happen according to the laws of physics, And when you do those calculations, you get a supernova and then you get a collapse and you get a black hole. And the black holes that are formed are about the size of black holes that we see out there in the universe. So the story sort of all hangs together. There's you know, little bits of it that are circumstantial. You can't actually see the whole life cycle of a star, but we try to tell a complete scientific story and probe it from lots of different angles, and it mostly hangs together. Yeah, you mean, like we can sort of think about how a star works and predict what's going to happen, and some of sometings a black hole will form, and you can also sort of see these evidence of them out there, and so it matches what you predict and it also matches what do you see right now. Yeah, and we can also see when a black hole doesn't form, because if there's not enough mass to make a black hole, then instead it will make a neutron star as other very very dense object, but not quite a black hole. It's part of a gray hole. Yeah, And we see those also, and that helps us validate, like in general, our understanding of stars and how they die and how they collapse, so we can predict not just when it makes a black hole, but when it fails to make a black hole, and our models also describe that pretty well. All right, well, I think that answers the question. We can predict that they come from the king and collapsing stars, and you can also see them out there that have the black holes that have come from collapsing stars and some that came a long time ago from the king stars. All right, let's get into our last question. But first we'll do the side question here, Daniel, and this one is sort of about your emotional state. Did this one come from a reader or your your parents? This one came from a listener here it is. Hey, guys, it's Daniel from the UK. Here. I've been thinking a lot about this recently, and I thought who better to ask it too? Then you, guys. I mean, you've got a lot of podcasts You've thought about the universe and fast get all the various questions that no one knows the answers to and I'm just thinking, do you ever get a bit sad and depressed that you probably won't be alive long enough to find out some of these big answers? Are there aliens? What they like? What stark matter? What's the meaning life? You know? What's inside a black hole? Does the universe ever end? I don't know. I'm excited for the future and to see what we discover, but also occasionally, you know, true in the extertential crisis, I'll be a bit bummed out about the fact I probably won't be alive to find out a lot of these things. Cheers, all right, great question, thank you, And yeah, Daniel, it's sort of an interesting question. I guess are they concerned about you, do you think, or are they worried that you're leading an unhappy life? I think they're just sort of capturing the feeling of living in primitive times. You know, we know that we know so little about the universe, and we hope that our Greek grandchildren in their great grandchildren will know more. And that's exciting, but it's also sort of frustrating because we know the information is out there. We know humans eventually will probably figure this stuff out. Somebody will know the answers to these questions that keep us up at night, and yet we probably will not or we may not, depending on how smart the next generation is, and that is sort of frustrating but exciting. Well, the question is sort of like, are you sad that you mind in your lifetime because you devoted your life to answering some of these big questions, Like are you a little bit sad that you may not know the answers by the end of your life? Like you may you may never know the answers. Well, I'm planning to invest in cryogenics so that a year before I die, I can just freeze my body and then thought every hundred years or so instead of good an update on the physics. But if you did right before you die, you would just be dying fifty years into the future. That's right. I'll spend my last year sort of like surfing through the future learning about what happens in physics. You want to spend the last year of your life in school, is what you're saying. I've spent all of my life in school so far. I'm in like of hundredth grade right now. Yeah, and I guess you haven't had enough. It sounds like a premise for a show called Futurama exactly. So it's really fun. But you know, even if we get the answers to those questions, then our descendants who know those things about the universe, they're going to have new questions. Because we know the answers to questions that people puzzled over five hundred years ago. We know those things definitively, but we're still tortured with new questions about the universe. So it's not like this ever going to be a moment where we're like, Okay, yeah, we got it. We have it figured out. Because we are curious, because we wonder, and because we explore, they're always going to be more things to wonder about. And I also kind of get this answer. What's fun for you for scientists, for all of us who sort of think about these things is sort of the asking of the question. You know. It's like it's the journey, not the destination. Like it's fun just to be part of this moment in time we're asking these questions and learning more about it. It's almost like if you actually found out the answer, it would be not as fun anymore. Depends on what the answer is. But yeah, often the joy isn't asking the questions, because we certainly ask a lot more questions than we get answers. So the sign that you're a scientist, it might be that you like asking questions and puzzling over them, not necessarily just getting the answers. All right, Well, we'll get to our last question, and it's it's an interesting one about maybe sending your in laws to another planet. So we'll get into that, but first let's take another quick break. All right, we're answering listener questions today here on the podcast, and we've gotten some awesome questions, and we've talked about some awesome answers here about dinosaurs, asteroids and black holes and collapsing stars. And our last question comes from Nick. Hello, Daniel and Jorge and all the guests hosts. I really appreciate the podcast. My question today is if we could put someone on a planet near another are, for example approximates Centauri, and have them try to detect the civilization on Earth with current Earth technology, would they be able to thank you very much asking for a friend. I guess if you could banish someone to another planet like a Proximus Centauri, and Nick wants to know could they find this with current Earth technology? Like, do you think he's asking if they would be out there forever or lost? Or is there a sort of an easy way to get back to Earth. I don't think he's thinking at all about sending one of his friends or your in laws to Proximates Centauri. I think he's wondering about if there are aliens on Proximates Centauri, would they have discovered that we exist if they had sort of like earthlike technology? Oh? I see, I see all right, yeah, so like if there is already somebody there, maybe your future in laws. You never know, right, I mean life takes interesting turn sometimes they could be futured in laws. How would they find this? I guess? Yeah, it's a fun question because we don't know where the aliens might be, and so it's worth asking should we have heard from them or should they have discovered us? So it's an important sort of thought experiment. If there were aliens there, shouldn't we have heard from them? Because you know, there are only four light years away, which means if they knew that we are here, it wouldn't take very long for them to send us a message back. Right. It's actually the kind of conversation we might be able to have much better than discovering aliens across the galaxy, where it takes fifty years to send a message. These are basically our neighbors, and so it's important to wonder whether or not they would even know that we are here. I see. Well, let's maybe break it down a little bit. What is Proxima Centauri. It's a it's a nearby star or a nearby planet. It's a nearby star. It's a red dwarf, and it's got two planets that we've discovered around it, and it's only three point seven light years away. It's the closest star to our sun. So if there's any place we'd like to discover friendly aliens, then it's Proximus Centre because it's very close by. And then there are other stars almost as close by, but this one edges out the other ones, and it's the closest I see, and these planets are sort of habitable, you think, all right, yes, so there are two planets out there, Proximus Centaurri B and Proximates Centauri C. One of them, Proximate B, is orbiting within proximates habitable zone, meaning that like the temperatures are right for liquid water to exist on its surface. But you know, Proximus Centauri is actually a flare star. It gets like brighter and darker, and so it's not really clear whether any aliens could survive there. Interesting, and so it's it's the closest basically outposed or like non empty space that is the closest to us in our galaxy, right, that's right, right, Well, the question is if they have if there are aliens, if you put a scientist there with Earth technology, or if there are aliens they're living there, could they find us? Would they know we're here? And three point seven light years away is not that far, right, Like if I shine a flashlight in their direction right now tonight, it would get there in four years. It would get there in four years, and some of those photons from your flashlight would actually hit Roxima B. And so that's pretty exciting because your flashlight sends out light in a cone, and that cone expands, so when you get really really far out, that cone is really really wide, so your flashlight would cover like the entire Solar system out there in Proxima b every point in that solar system could potentially see your flashlight, but of course it wouldn't be very bright anymore because it would have spread out so much. Right, Well, what you could use maybe a laser. You could use a laser. And so that's exactly the issue is that we could send signals to Proximates Centauri using Earth technology and they could discover it if it was sent intentionally. Right, So, if we on purpose sent a message to Proximates Centauri that was focused saying like we want to beam a whole bunch of light right at this one place, then yes, we could send a message that they could discover. But if we're just sort of like sending signals out into space generally, then it'd be much harder to discover it because those signals would die off very very rapidly. You mean, the way we're like broadcasting TV signals and radio signals out there and into the atmosphere and out into space. Like that's not focused, right, Like that's just going everywhere, and so that would get diluted pretty quickly, exactly. And if they have technology and Proximus Centauri like we do, you know, a dish like Aricibo or something. They only see those kinds of signals if you were within about a light year of the source. So to detect signals from Earth using a dish like Aricibo, you'd have to be within about a light year of Earth. So if you had a dish like that on Approximus Centauri, we'd have to send signals that were like sixteen times stronger in order for an aero Cibo on Proximus Centauri to pick them up. Interesting, or I guess maybe the hope that they have a bigger receiving dish, right, Yeah, maybe they have a sixteen times bigger dish than they could see us. But next question was sort of like with current Earth technology, and so if we sent a directed message there, then they could definitely pick it up. If we have no idea that they're there and we're not sending them many messages, which is sort of like blathering out into the universe, then it's unlikely with current Earth technology they would even know that we are here. I see, So they can't eaves drop on us that what you're saying, they can which off of our Netflix subscription, that's right, And the latency from there is terrible. Yeah, they're barely just watching season one of Springer things buffering, buffering, buffering for four years. All right, well, I guess that's sort of talking to them. But could they see us? Like we can see we can sort of see them, right, we can see these planets out there, and you can actually sort of almost take pictures of it, right, it's not just being detected by the gravity there. Could they see us? And could they take a picture of us almost? Like these are the closest planets and so if we use Earth like technology, we can tell that those planets are there. And now we can make some measurements of what's in the atmosphere of those planets, Like we don't yet have telescopes that are powerful enough to directly take pictures of them. That we will in about ten or fifteen years, but currently what we can do is like see how the light changes as it passes through the atmosphere of those planets and use that to get estimates for what's in the atmosphere, and like is their methane? Is there oxygen? Are there signs of life in that atmosphere? What's the weather like on those planets? Interesting? Yeah, they could tell that we are polluting our atmosphere and not doing a great job and maybe decided not to con visit us. Yeah, but it's not easy to just look at the atmosphere and conclude that life exists. People used to think, well, all you need to do is see oxygen, because oxygen is evidence of life. But now we have lots of ideas for how you can make a lot of oxygen on the surface of a planet without life. And we recently discovered, for example, phosphene on Venus, or people thought we did. That was thought to be like clear evidence of life, but now it turns out that that wasn't such a strong discovery. So it's a really vibrant and fast moving field of study. Right now, what can you learn about potential life on the surface just from understanding the atmosphere. But in about ten or fifteen years, some of these other devices like the thirty meter telescope where the giant Magellan telescope will turn on, and those will give us much better resolving power and they might be able to take direct pictures and give us a set for what's going on on those planets. Right, Yeah, that would be cool. I wonder if we could also send a probe, right like four light years away, you know, maybe fifty years we could send something there that reaches there. Right, Yeah, it's possible. It would take a long time because a probe like that would have to accelerate to a good fraction of the speed of light to get there in fifty years, but it would be pretty awesome. The most distant probe we have ever sent only recently left the Solar system, so it takes a long time. Though our technology has improved a little bit. Yeah, just make them faster, I guess. So this is kind of us sort of talking and seeing each other. But it turns out that maybe we've actually heard from Proximus centaurians. Right. There's a story of a famous signal that came from there recently. Yeah, it said help, we're Jorges in laws and he trapped us here on Proximus centar. No. No, it's more like, hey, we want to meet this horhe we have some good prospects for him here. This was a fun story, though it was a brief excitement. Last year they collected some signals at the Park's telescope in Australia and it's part of the Breakthrough Listen project, which is looking for evidence of life in the universe by listening for potential signals. They are scanning lots of frequencies and looking for potential technological signals, and people got really excited for a few weeks that maybe we had heard something. And it's a really difficult problem to know how to scan radio signals for signs of life, because we don't know what that life would be like. We don't know whether it be a technological civilization, and we don't even know if they would use radio, how they would structure a message. It's a hard thing to do, but there are some basic things to look for if you want a message that comes not from Earth, and one of those, for example, is to see that there are shifting frequencies. You know, if you send a message from something that's in motion that has a velocity, then the waves from that object get shifted by the Doppler shift, because, like if it's coming from Proximates Centauri, that planet is going around it's star, and so it's moving away from us and then towards us, and away from us and then towards us. So a message from there should have that kind of Doppler shift as that planet goes around the star. Or maybe even a different kind of Doppler shift as the planet is spinning, if the message actually comes from the surface. So they look through all the information to get from the telescope, and they actually found one that seemed to have the right Doppler shift. Interesting, I see, because you want to make sure that it's not a signal that's coming from the star right, which is shining brightly. If you see something that looks like it's coming from something that's moving around the star, then you're like, hey, that came from the planet, and planets don't usually have bright sources, so it might be technology from these ailings, that's right. And then the second thing they do is they make sure that it really is coming from that direction. So they take the telescope and they pointed in another direction sort of like off of the target, and they hope that the signal disappears, and then they turn it back towards the target and the hope that the signal reappears. And so this one also survived that test, so it had the right Doppler shift and it seemed to be coming from that direction. You know, it only appeared when we were pointing towards proximates centauri. So people kind of excited and they start digging into the details, like what is this message? Is there information in it? Can we decoded? There was a moment we thought maybe we had heard a signal from the aliens. And it must be really exciting but also difficult to work in this field where every day could be the day that you like change the history of humanity by hearing from aliens or not. You know, it must be hard to maintain your excitement every time it's either a big discovery or a big disappointment. But you know that's that everyone is at the work right every day you go to work, it could be the day you come up with the brilliant ideal that changes the world. It could be. And so what they found when they dug deeper into the signal is they actually discovered a bunch of other signals in their data which looked almost exactly the same And we're clearly not coming from Proximus centauri because they picked up these other signals and pointing in other directions. So what they discovered is that it's some weird kind of interference. I think it's still not totally understood, but it might be some weird kind of connection between some are kind of signal. It's the aliens here on Earth that are giving you signal, not the ones in Proximus sentari. But for a moment we thought maybe we had heard something from intelligent technological civilizations on our neighboring star. That would have been awesome. And I guess my question is, is Proximus centaur is everyone they're a centaur like? That would be pretty cool, the whole planet of half horse people. It's Proximus centauri. So there's center adjacent. They're approximately center like person, not the perfect balance. Yeah, you gotta go to like asymptotic centauri to get to you know, almost get fully centaurs, that's right, or O G Centauri for the for the true stuff, maximum Centauri. That's where you gotta go. Ultimate Centauri. There you go, best centaur. Al right, well, I think that answers nixt question and the answer is cut someone in approximate centauri fines And the answer is yes. But you need to be pretty focused on listening for us, and you need to be pretty focus on sending a signal here like it can just sort of happen by accident, at least with current Earth technology, that's right. And with technology that we'll have in a dozen or so years, we might be able to see the surface of those planets and see what's going on and learn something about the surface of another planet. Would you go there, Daniel? Would you pick up and you know, right before you die, so that you wouldn't have to waste your time here? Would you go there? No? I really don't like travel. I don't even really like being on an airplane, So spaceships no, thank you. Would you'd be asleep and you'd be almost dead anyway, I would say, why not? Right? M I guess it depends on the snacks n see did you eat while you're sleeping and they stuff up your nose while you're taking your nap? And the peanuts they feed me bananas without even peeling them. Oh boy. But let's move on here and thank everyone for sending their questions. We love answering these questions. We love tapping into your curiosity and getting us to think about these crazy scenarios and wonderful mysteries about the universe. That's right, So please continue to send us your wonderings and your questions and your puzzles to Questions at Daniel and Jorge dot com. We can't get enough. Yeah, we hope you enjoyed that. Thanks for joining us, See you next time. Thanks for listening, and remember that Daniel and Jorge explained. The Universe is a production of I Heart Radio. For more podcast from my Heart Radio, visit the i heart Radio app, Apple Podcasts, or wherever you listen to your favorite shows. Ye