WEBVTT - Why didn't we evolve around a red dwarf star? 0:00:08.440 --> 0:00:11.520 Hey, Daniel, do you believe in luck? Do you think 0:00:11.560 --> 0:00:15.000 you're a lucky person? I'm not sure. I guess I'm 0:00:15.000 --> 0:00:17.800 pretty happy with how things have turned out. Oh yeah, 0:00:17.800 --> 0:00:20.759 But was that luck or was it inevitable? I'm sure 0:00:20.800 --> 0:00:23.680 there was a lot of randomness involved. I guess I'd 0:00:23.680 --> 0:00:26.880 have to study the multiverse to see how often Daniel 0:00:26.880 --> 0:00:29.200 gets to be a physics professor. But wait, is that 0:00:29.240 --> 0:00:32.680 the lucky outcome. Wouldn't the lucky outcome be the one 0:00:32.680 --> 0:00:34.400 where you get to be a movie star or a 0:00:34.440 --> 0:00:38.600 billionaire or maybe a billionaire movie star physics professor. That's 0:00:38.600 --> 0:00:40.800 a lot of titles there. It might cause the universe 0:00:40.920 --> 0:00:44.960 to collapse on itself, physicists always ending the universe. We 0:00:45.040 --> 0:00:47.160 might have caused it, but it doesn't mean it's our fault. 0:00:47.360 --> 0:00:50.640 That sounds like a logical contradiction. Wouldn't that also collapse 0:00:50.720 --> 0:01:09.360 the universe into a puff of logic? Hi am Jorhanmay, 0:01:09.360 --> 0:01:12.400 cartoonists and the creator of PhD comics. Hi, I'm Daniel. 0:01:12.440 --> 0:01:15.280 I'm a particle physicist and a professor at UC Irvine, 0:01:15.400 --> 0:01:18.399 and I'm doing my best to understand the universe without 0:01:18.440 --> 0:01:20.600 collapsing it. You're doing your best. I feel like your 0:01:20.600 --> 0:01:23.800 best is not enough, like I guarantee is not enough. 0:01:23.840 --> 0:01:28.480 Maybe you should look into that before doing it. I'll 0:01:28.560 --> 0:01:32.360 check with my legal department. I'll do twice my best 0:01:32.400 --> 0:01:35.959 time of that still not enough. Ending the universe twice 0:01:36.360 --> 0:01:38.920 is still ending the universe. Maybe it's like negative signs. 0:01:38.920 --> 0:01:40.280 You know, if you do it twice, it comes back. 0:01:40.400 --> 0:01:42.360 But then are you going to be a physics professor again? 0:01:43.040 --> 0:01:45.440 Are we going to be that unlucky? Maybe when everything 0:01:45.440 --> 0:01:47.600 snaps back, that's when I get to be a billionaire. 0:01:47.760 --> 0:01:50.559 But anyways, welcome to our podcast, Daniel and Jorge Explain 0:01:50.640 --> 0:01:53.960 the Universe, a production of iHeartRadio, where we try our 0:01:53.960 --> 0:01:57.240 best to make sense of this crazy universe. When you 0:01:57.320 --> 0:01:59.960 look out there in the cosmos and try to understand 0:02:00.120 --> 0:02:02.400 the way things are, the way things might be, and 0:02:02.600 --> 0:02:05.640 how it all can possibly make sense. We do our 0:02:05.640 --> 0:02:10.160 best to cram this incredible, giant, fantastical universe into our 0:02:10.200 --> 0:02:13.680 tiny little primate brains and squish it all around until 0:02:13.720 --> 0:02:16.760 it makes sense to us and hopefully makes sense to you. Yeah, 0:02:16.800 --> 0:02:20.000 it is an amazing universe, or maybe an amazing multiverse, 0:02:20.080 --> 0:02:22.160 or might be more than one universe out there, But 0:02:22.200 --> 0:02:24.480 at least the one we're in. It seems pretty amazing, 0:02:24.520 --> 0:02:26.960 pretty awesome to explore and to ask questions about, and 0:02:27.000 --> 0:02:29.880 to wonder about the logic of it. Yeah, as we 0:02:29.919 --> 0:02:32.560 look out into the universe, we wonder why is it 0:02:32.600 --> 0:02:35.480 this way and not some other way? Why are we 0:02:35.520 --> 0:02:37.440 in this part of the universe and not some other 0:02:37.440 --> 0:02:39.839 part of the universe? Are we lucky that we ended 0:02:39.919 --> 0:02:42.120 up here? Was it just a fluke or is it 0:02:42.200 --> 0:02:45.880 pretty common our experience of the universe? Is the universe 0:02:45.880 --> 0:02:48.320 guaranteed to be logical? Daniel? Do you think is it 0:02:48.360 --> 0:02:51.920 logical that the universe is not logical? Yeah? A guarantee 0:02:51.960 --> 0:02:56.200 itself rests on logic, and so if the universe is illogical, 0:02:56.240 --> 0:02:59.760 then it cannot provide any kind of guarantees at all. 0:03:00.120 --> 0:03:03.040 Philosophically speaking, we don't know why the universe makes sense 0:03:03.080 --> 0:03:05.240 to us at all, Like, why is it even possible 0:03:05.440 --> 0:03:09.239 to describe it in terms of pretty simple mathematical stories. 0:03:09.440 --> 0:03:11.560 We don't know, But we do know that it seems 0:03:11.600 --> 0:03:14.360 to work, and it works really really well. Well, the 0:03:14.440 --> 0:03:17.799 universe is random, right at the quantum level, things are random? 0:03:18.000 --> 0:03:20.799 Is random the same as logical. Well, that's a really 0:03:20.800 --> 0:03:24.359 interesting point. Because even if quantum mechanics is random, it's 0:03:24.360 --> 0:03:28.239 still also logical, Like quantum mechanics makes very specific predictions 0:03:28.240 --> 0:03:31.400 for the probabilities of different things to happen, even if 0:03:31.400 --> 0:03:35.040 it doesn't actually pin down what will happen. So quantum 0:03:35.040 --> 0:03:37.760 mechanics being random doesn't mean it's like crazy, you're out 0:03:37.800 --> 0:03:40.840 of control. It still makes very specific predictions about what 0:03:40.920 --> 0:03:44.320 can and cannot happen and the probabilities of those things happening. 0:03:44.640 --> 0:03:48.000 Right although technically acquantic to quantum physics, like a pink 0:03:48.080 --> 0:03:51.120 unicorn could technically appear in front of me out of 0:03:51.160 --> 0:03:53.600 the boob right now, or in front of any of 0:03:53.680 --> 0:03:56.800 us right now, right and that would be logical. According 0:03:56.880 --> 0:03:59.560 to physicists, that would be logical, even though it would 0:03:59.560 --> 0:04:02.360 also be fantastical. And that's something we're always trying to 0:04:02.400 --> 0:04:04.680 understand about the universe. We see what happens to us, 0:04:04.720 --> 0:04:07.800 we wonder was that just a random, lucky fluke, or 0:04:07.960 --> 0:04:09.720 is that the kind of thing we expect to see 0:04:09.800 --> 0:04:13.720 in the universe. And there's this overriding principle in science 0:04:13.760 --> 0:04:17.480 called the Copernican principle, which argues that our experience is 0:04:17.560 --> 0:04:20.839 not weird, that everywhere in the universe is the same, 0:04:20.920 --> 0:04:24.240 and nothing is special anywhere, and so when we look 0:04:24.279 --> 0:04:26.200 out into the universe, we tend to try to explain 0:04:26.240 --> 0:04:30.479 what we see without resorting to lucky chances and random flukes. 0:04:30.800 --> 0:04:34.039 But lucky flukes is why we're here, Daniel, Lucky flukes 0:04:34.080 --> 0:04:38.320 are the best. Well, every individual person, of course, has 0:04:38.360 --> 0:04:42.839 an almost astronomically tiny chance of ever existing with all 0:04:42.880 --> 0:04:45.279 of their constituent details. But what we don't know is 0:04:45.279 --> 0:04:48.320 what are the chances of any person existing? You know, 0:04:48.320 --> 0:04:50.279 one of the deep questions in the universe is what 0:04:50.320 --> 0:04:53.520 are the chances for life evolving, for intelligent life to evolve? 0:04:53.600 --> 0:04:56.240 Are we unusual or are we common in the universe? 0:04:56.640 --> 0:04:58.560 And we'd like to be able to explain our existence 0:04:58.600 --> 0:05:01.760 here without resorting to a one in a trillion chance 0:05:02.000 --> 0:05:03.760 of all of this is happening. Well, it seems like 0:05:03.760 --> 0:05:06.839 there's a sort of a fine line between illogic and 0:05:07.279 --> 0:05:10.680 unlikeliness or as you said, improbability. Yeah, that's right, and 0:05:10.760 --> 0:05:13.039 often we can tell the difference, you know, we have 0:05:13.200 --> 0:05:16.240 just this one example of our lives and the part 0:05:16.240 --> 0:05:18.640 of the universe that we can see. And often we 0:05:18.680 --> 0:05:20.440 look out into the universe and we see stuff that 0:05:20.560 --> 0:05:23.520 seems weird, that seems like a weird coincidence, and we 0:05:23.680 --> 0:05:25.640 want to try to explain it. We don't want to 0:05:25.680 --> 0:05:27.520 just like brush it under the rug and say, hm, 0:05:27.880 --> 0:05:31.000 that's random, seems weird. I guess sometimes you just get lucky. 0:05:31.200 --> 0:05:33.680 We'd like to understand if there's something else going on, 0:05:33.839 --> 0:05:37.000 something deeper behind it. But you know, there isn't always 0:05:37.000 --> 0:05:39.640 an explanation, like, for example, the sun in the moon 0:05:39.760 --> 0:05:42.559 take up about exactly the same space in our sky, 0:05:43.080 --> 0:05:47.159 which allows for very dramatic eclipses, and that's just a coincidence. 0:05:47.240 --> 0:05:51.920 Sometimes coincidences happen, but sometimes they do have deeper explanations 0:05:52.000 --> 0:05:54.039 that we can look for. Yeah. So one way we 0:05:54.120 --> 0:05:56.840 try to explore the logic of the universe is by 0:05:56.880 --> 0:06:00.200 coming up with situations in our minds or that maybe 0:06:00.400 --> 0:06:03.159 we get hints at out there of events or things 0:06:03.160 --> 0:06:05.919 that seem to break the logic of the universe. And 0:06:06.000 --> 0:06:09.479 these are paradoxes. Yeah. One very famous paradox is the 0:06:09.520 --> 0:06:13.880 Fermi paradox, which says where are all the aliens? You know, 0:06:13.960 --> 0:06:16.640 if the galaxy is really really old and actually filled 0:06:16.680 --> 0:06:19.760 with stars and planets, then maybe it should also be 0:06:19.839 --> 0:06:22.760 filled with aliens, and why haven't we seen any of 0:06:22.839 --> 0:06:25.600 them yet? Why haven't they sent us messages? This is 0:06:25.640 --> 0:06:28.719 called the Fermi paradox because if you accept all of 0:06:28.720 --> 0:06:31.800 those assumptions, then we should have heard from aliens, and 0:06:31.960 --> 0:06:34.760 yet we haven't. So paradoxes are fun because they make 0:06:34.800 --> 0:06:37.919 you re examine those assumptions to say, well, we haven't 0:06:37.920 --> 0:06:41.600 heard from aliens, then which of those assumptions must be wrong? 0:06:41.680 --> 0:06:44.279 And what does that tell us about the universe. Well. 0:06:44.279 --> 0:06:47.840 Another famous paradox is the grandfather of paradox. Right, This 0:06:47.880 --> 0:06:49.880 idea that if you go back in time and you 0:06:49.920 --> 0:06:54.400 somehow prevent your grandfather from giving birth or making your 0:06:54.440 --> 0:06:58.240 father or mother haven't, then that creates an illogical consistency 0:06:58.240 --> 0:07:00.719 because then how could you have existed to them prevent 0:07:00.760 --> 0:07:03.279 your grandfather from doing that. That's one of the most 0:07:03.279 --> 0:07:07.400 famous logical paradoxes, right, And that's like something that doesn't 0:07:07.440 --> 0:07:11.280 make sense logically, but it could maybe happen. Well, we 0:07:11.320 --> 0:07:14.240 don't know if that could maybe happen exactly. That's one 0:07:14.240 --> 0:07:17.360 of the paradoxes inherent in time travel. It's the kind 0:07:17.360 --> 0:07:19.440 of thing that makes people wonder like, well, what are 0:07:19.480 --> 0:07:22.600 we overlooking? Is there something in time travel which would 0:07:22.600 --> 0:07:26.000 prevent that from happening. And there are various ideas about 0:07:26.160 --> 0:07:29.880 cosmic censorship that might prevent paradoxes from cropping up if 0:07:29.880 --> 0:07:32.600 you could actually achieve time travel. So you're right, it's 0:07:32.600 --> 0:07:35.680 a really interesting idea and it focuses your thinking on 0:07:35.720 --> 0:07:37.640 the issues to say, well, what can we do to 0:07:37.680 --> 0:07:40.360 prevent this paradox from happening, because, as you say, the 0:07:40.480 --> 0:07:44.960 universe seems logical, and so anything that creates a contradiction, 0:07:45.000 --> 0:07:48.400 a logical contradiction, we don't think that that could exist. 0:07:48.440 --> 0:07:51.520 The universe can't exist in two states that disagree with 0:07:51.520 --> 0:07:56.280 each other simultaneously. Yeah, so there is another interesting paradox 0:07:56.360 --> 0:07:59.560 out there. Then maybe the challenges the logic of us 0:07:59.600 --> 0:08:02.160 being here in the first place, or at least of 0:08:02.200 --> 0:08:04.520 our son being here in the first place. Yeah, asked 0:08:04.520 --> 0:08:07.320 the question basically of why we're not looking up into 0:08:07.320 --> 0:08:11.120 our sky and seeing a different kind of star than 0:08:11.160 --> 0:08:15.600 the one that we have, or stars plural. So today 0:08:15.600 --> 0:08:23.000 on the podcast, we'll be asking the question what is 0:08:23.160 --> 0:08:27.240 the Red Dwarf paradox? The real Red Dwarf paradox is 0:08:27.440 --> 0:08:30.680 why don't more people watch the show The Red Dwarf. 0:08:31.720 --> 0:08:33.640 Is that a show? I've never seen it? Is that 0:08:33.760 --> 0:08:35.640 a show? Oh my gosh, it's like one of the 0:08:35.679 --> 0:08:39.120 most hilarious can't be science fiction shows ever. I've never 0:08:39.160 --> 0:08:41.120 heard of it. Where does it er? I think it's 0:08:41.120 --> 0:08:43.720 on the BBC, but you can find it online. Is 0:08:43.720 --> 0:08:46.480 it really hilarious show? Sort of in the vein of 0:08:46.559 --> 0:08:50.560 Hitchhiker's Guide to the Galaxy. Definitely not hard science fiction. Well, 0:08:50.600 --> 0:08:55.200 the paradox maybe, is how come I've never shown I mean, 0:08:55.600 --> 0:08:59.079 I've seen several seasons of Doctor Who. There you go, Yeah, well, 0:08:59.080 --> 0:09:02.439 maybe it only exists in another multiverse, and that's proof 0:09:02.520 --> 0:09:06.319 that I came from another universe. You do seem out 0:09:06.360 --> 0:09:09.079 of this world, Daniel, you mean out of my mind. 0:09:09.480 --> 0:09:12.000 But so, the Red Dwarf paradox apparently is a thing. 0:09:12.120 --> 0:09:14.440 I had also never heard of this, the paradox or 0:09:14.480 --> 0:09:17.120 the show before coming into this episode. But it's sort 0:09:17.120 --> 0:09:19.160 of like a thing that physicists talk about, right. It 0:09:19.360 --> 0:09:22.360 is a thing that physicists and biologists and basically everybody 0:09:22.400 --> 0:09:25.400 who's curious about why we ended up on this rock 0:09:25.520 --> 0:09:29.760 around this star. Fundamentally, we're always asking the question, is 0:09:29.800 --> 0:09:33.280 our experience unusual? Do we have to resort to shrugging 0:09:33.280 --> 0:09:35.800 our shoulders and saying, well, I guess we were just lucky, 0:09:35.960 --> 0:09:37.720 or is there a reason that our experience is this 0:09:37.760 --> 0:09:40.840 way and not some other way? And in this particular case, 0:09:40.840 --> 0:09:43.920 we're wondering about why our star is one of these 0:09:44.000 --> 0:09:47.920 yellow stars instead of a red dwarf star. Well, this, 0:09:48.200 --> 0:09:50.680 like you said earlier, this sort of seems similar to 0:09:50.720 --> 0:09:53.760 the Fermi paradox, which is sort of this idea that 0:09:53.800 --> 0:09:56.400 we should have been contacted or seen aliens right now, 0:09:56.400 --> 0:09:59.440 but we haven't, given the size of the universe. But 0:09:59.559 --> 0:10:03.440 I feel like those are not really logical paradoxes, right Like, 0:10:03.600 --> 0:10:07.080 strictly speaking, it's not a logical there's no logical contradiction here. 0:10:07.200 --> 0:10:09.959 It's just like an unlikeliness. Yeah, that's true. I mean, 0:10:10.000 --> 0:10:12.520 the set of assumptions, when you combine them, suggest that 0:10:12.559 --> 0:10:14.560 it would be very unlikely for us to not be 0:10:14.679 --> 0:10:20.520 contacted by aliens. So either we're just unlucky or there's 0:10:20.520 --> 0:10:22.600 some other reason one of the assumptions that goes into 0:10:22.640 --> 0:10:24.440 it is wrong. And so you can always explain these 0:10:24.440 --> 0:10:26.120 things away and say, oh, well, maybe it's just one 0:10:26.200 --> 0:10:28.480 a million chance, and that's what it is. But you 0:10:28.480 --> 0:10:31.479 can also sometimes make progress by digging into those assumptions 0:10:31.480 --> 0:10:34.280 and saying, is one of those wrong, let's take another look. 0:10:34.760 --> 0:10:37.239 You mean, it's sort of like a tool to examine 0:10:37.280 --> 0:10:40.839 our assumptions about the universe, or as someone else might 0:10:40.880 --> 0:10:45.960 come complete guesses. Yeah, but it's a basic part of science. 0:10:46.000 --> 0:10:48.080 You know, anytime you think you have an understanding of 0:10:48.080 --> 0:10:50.719 the universe, you then think about what the consequences are. 0:10:50.960 --> 0:10:52.880 You know, if the universe is this way, then I 0:10:52.880 --> 0:10:55.040 should be able to prove it by seeing this thing. 0:10:55.360 --> 0:10:57.720 And if you don't see that thing happening, then you wonder, well, 0:10:57.840 --> 0:11:00.960 what's wrong with my idea of the universe? When we thought, oh, 0:11:00.960 --> 0:11:02.959 the universe would make more sense if it had Higgs 0:11:03.000 --> 0:11:05.400 Boson in it, let's go look for it, and we 0:11:05.520 --> 0:11:07.599 found it. Now, if we hadn't found it, then we 0:11:07.640 --> 0:11:10.160 would have to go back and re examine those assumptions 0:11:10.160 --> 0:11:12.560 that suggested it does exist and wonder which one of 0:11:12.559 --> 0:11:15.240 them were wrong. All right, Well, this red dwarf paradox 0:11:15.280 --> 0:11:17.839 basically just real quickly in a nutshell. It kind of 0:11:17.880 --> 0:11:20.520 asked the question that you asked earlier, which is, why 0:11:20.640 --> 0:11:23.240 isn't our star a red dwarf. Our son is a 0:11:23.320 --> 0:11:26.960 nice yellow or white I guess technically white ball of fire. 0:11:27.040 --> 0:11:29.800 It's not a red, it's not a dwarf, and so 0:11:29.920 --> 0:11:32.120 that's kind of what the paradox is about. Yeah, that's 0:11:32.160 --> 0:11:34.080 about it all right. Well, as usually, we were wondering 0:11:34.080 --> 0:11:36.520 how many people out there had asked themselves this question, 0:11:36.600 --> 0:11:40.079 why isn't our son different? Why isn't it a red dwarf? 0:11:40.320 --> 0:11:42.920 So thanks very much to everybody who participates in this 0:11:43.040 --> 0:11:45.560 segment of the podcast, and we would love to hear 0:11:45.840 --> 0:11:47.959 your voice out there. Those of you who have been 0:11:47.960 --> 0:11:50.680 listening for a while but haven't yet chimed in, please 0:11:51.080 --> 0:11:54.640 write to us to participate to questions at Daniel Horge 0:11:54.800 --> 0:11:56.640 dot com. So think about it for a second. Have 0:11:56.760 --> 0:11:59.440 you ever asked yourself on a nice sunny day, why 0:11:59.480 --> 0:12:02.520 our star isn't red? Here's what people had to say. 0:12:02.720 --> 0:12:05.040 I feel like thybe it's too big, big to be 0:12:05.080 --> 0:12:07.840 a red dwarf. That's it. I really don't know the 0:12:07.840 --> 0:12:09.560 answer to this one. I would just imagine that it 0:12:09.559 --> 0:12:13.080 doesn't have enough mass to either collapse into itself a 0:12:13.120 --> 0:12:15.000 form a black hole or become a red giant. I 0:12:15.040 --> 0:12:18.000 don't know all a son didn't follow his diet and 0:12:18.200 --> 0:12:20.880 has eaten a lot, so it's too big to become 0:12:20.880 --> 0:12:23.480 a red dwarf. I think the main reason our star 0:12:23.600 --> 0:12:26.240 isn't a red dwarf is just because it's something has 0:12:26.280 --> 0:12:28.400 to do with like the amount of mass it has 0:12:28.360 --> 0:12:30.640 in the beginning and when it begins, because some stars 0:12:30.679 --> 0:12:33.280 go supernova and some stars just white doors. I don't know, 0:12:33.280 --> 0:12:35.120 I get mixed up. Maybe our son is not old 0:12:35.200 --> 0:12:37.880 enough to be a red dwarf. Maybe it still has 0:12:37.920 --> 0:12:39.960 a lot of fool to be larger and right, dar, 0:12:40.360 --> 0:12:43.120 I don't think that our star is supposed to be 0:12:43.679 --> 0:12:49.240 a red dwarf. I think that it may someday be 0:12:49.280 --> 0:12:53.680 a red dwarf given enough time, But I think that 0:12:53.840 --> 0:12:59.640 it's not quite yet reached that phase of stellar evolution. 0:13:00.320 --> 0:13:02.520 All right, A lot of interesting answers here, I like 0:13:02.600 --> 0:13:05.319 the one about the Sun not following a diet, yeah, 0:13:05.559 --> 0:13:07.559 or the one about it not being old enough. But 0:13:07.679 --> 0:13:10.680 I am disappointed nobody brought off Superman. I mean these answers, 0:13:11.679 --> 0:13:13.760 what does Superman have to do with the Sun being 0:13:13.840 --> 0:13:16.720 yellow or red? You don't know. I don't know, Yeah, 0:13:16.840 --> 0:13:20.800 you don't know. Some basic mythology about Superman. I spent 0:13:20.840 --> 0:13:23.160 all my time watching the show Red Dwarf instead of 0:13:23.160 --> 0:13:26.000 reading Superman comics. Well, there you go. That's a multiverse 0:13:26.040 --> 0:13:27.680 I don't want to live in. So tell us what 0:13:27.760 --> 0:13:30.199 a Superman have to do with red stars. Yeah, it's 0:13:30.240 --> 0:13:33.720 a basic part of his mythology. So in the original comics, 0:13:33.760 --> 0:13:35.640 he grew up in a planet with the red sun, 0:13:36.360 --> 0:13:38.679 and so when he comes to Earth, he has all 0:13:38.720 --> 0:13:41.840 these superpowers because our son is not red, it's yellow, 0:13:41.920 --> 0:13:44.920 and somehow that gives him his superpowers somehow. Wow, you 0:13:45.000 --> 0:13:48.520 just yadda yadded over all the crucial elements of it. Yeah, somehow, 0:13:48.800 --> 0:13:53.080 you know, like how physicists do somehow the Higgs boson 0:13:53.200 --> 0:13:55.840 is created in architectors. That's exactly what I wrote in 0:13:55.840 --> 0:13:57.839 the paper. Yeah, that was it basically. I mean, you 0:13:57.960 --> 0:14:03.520 use more words and formulas, but there's not much difference 0:14:03.559 --> 0:14:07.200 between Action comics in the Journal of Physics. I'm sure 0:14:07.240 --> 0:14:10.360 that Action Comics hired some physics consultants to work out 0:14:10.480 --> 0:14:13.000 the details, and there's somewhere in there archives there are 0:14:13.120 --> 0:14:17.120 formulas explaining how the yellow sun gives Superman his special powers. 0:14:17.160 --> 0:14:19.560 What does that mean that Superman doesn't have those powers? 0:14:19.640 --> 0:14:22.000 In the dark. Well later on, it's sort of it's 0:14:22.000 --> 0:14:23.720 sort of like he acts like a battery, kind of 0:14:23.800 --> 0:14:26.440 like he needs to recharge, he needs to sunbathe they 0:14:27.280 --> 0:14:31.440 to get his superpowers. I see. So kryptonite isn't his kryptonite. 0:14:31.440 --> 0:14:38.280 It's sunscreen. That's his kryptonite in the long run. Yes, okay, fascinating. Well, 0:14:38.360 --> 0:14:42.440 let's dig into this red dwarf paradox and how it 0:14:42.520 --> 0:14:45.720 might affect Superman, I guess, or all of us, because 0:14:45.720 --> 0:14:48.960 it'd be great if we were all Superman and women. Well, actually, 0:14:49.000 --> 0:14:52.160 what the redware paradox suggests is that most of the 0:14:52.320 --> 0:14:55.920 universe is basically Superman, because one thing that's really interesting 0:14:55.920 --> 0:14:58.320 about the universe is that most of the stars out 0:14:58.320 --> 0:15:01.840 there in the universe are red stars, not yellow like ours. 0:15:01.920 --> 0:15:04.120 All Right, well, let's dig into this topic and this 0:15:04.320 --> 0:15:06.920 red dwarf paradox, and it's starts with the basics. What 0:15:07.240 --> 0:15:10.400 is a red dwarf star? Daniel, So, a red dwarf 0:15:10.520 --> 0:15:12.880 is just a kind of star. Remember that a star 0:15:13.040 --> 0:15:15.800 is a huge ball of gas and it's squeezed down 0:15:15.840 --> 0:15:18.240 by gravity, so at its core it's hot enough and 0:15:18.400 --> 0:15:20.920 dense enough for fusion to happen, which is where the 0:15:21.000 --> 0:15:23.280 light comes from and why the star burns at the 0:15:23.280 --> 0:15:25.280 temperature at the core, and therefore the temperature at the 0:15:25.320 --> 0:15:28.400 surface depends on the mass of the star. The more 0:15:28.520 --> 0:15:31.240 gas you have, the higher temperature and pressure you have 0:15:31.280 --> 0:15:33.760 at the core of the star, and so the higher 0:15:33.760 --> 0:15:36.120 the temperature at the surface, and so the different color 0:15:36.240 --> 0:15:38.760 of the star. Remember that everything in the universe glows, 0:15:38.880 --> 0:15:41.800 and how it glows depends on its temperature. Our sun 0:15:41.880 --> 0:15:44.880 is a surface temperature of five or six thousand degrees kelvin, 0:15:44.880 --> 0:15:47.360 and so it tends to glow in our visible spectrum. 0:15:47.480 --> 0:15:50.560 Bigger stars are hotter, and so they tend to be bluer. 0:15:50.960 --> 0:15:54.760 Smaller stars are colder, and so they tend to be redder, 0:15:54.880 --> 0:15:58.560 and so a red dwarf star is a smaller, colder 0:15:58.640 --> 0:16:02.240 star that tends to be redder than our star. M 0:16:02.840 --> 0:16:07.160 I guess maybe can you explain why smaller means lower temperature? 0:16:07.360 --> 0:16:09.560 Is it because when you're smaller, you don't have as 0:16:09.600 --> 0:16:12.280 much fusion, if at all, inside the core of the 0:16:12.520 --> 0:16:15.560 gas cloud. There's definitely a close connection between the size 0:16:15.600 --> 0:16:18.480 of the star and its internal temperature, and that's just 0:16:18.520 --> 0:16:22.480 because of gravity. Like more mass means more gravitational pressure, 0:16:22.640 --> 0:16:25.120 which means higher temperature. We once topped our way through 0:16:25.120 --> 0:16:27.440 that thought experiment of like taking a big blob of 0:16:27.480 --> 0:16:31.200 gas and squeezing it down. Squeezing it down heats it 0:16:31.320 --> 0:16:34.800 up because you're basically applying pressure which pushes on all 0:16:34.800 --> 0:16:38.000 those molecules, turning them around to focus them back towards 0:16:38.080 --> 0:16:41.080 the center. You imagine like a big box containing cold gas. 0:16:41.360 --> 0:16:44.120 As you can strict that box, you're pushing on all 0:16:44.120 --> 0:16:47.000 the molecules that would have otherwise escaped, so you're giving 0:16:47.040 --> 0:16:49.360 them more and more energy. So as you squeeze down 0:16:49.440 --> 0:16:52.160 harder and harder, you're speeding up all those molecules, you're 0:16:52.200 --> 0:16:55.000 making them hotter and hotter. So a bigger blob of 0:16:55.080 --> 0:17:00.080 stuff has more gravitational pressure, which means a higher temperature. 0:17:00.240 --> 0:17:02.720 Something like Jupiter, which is also a ball of gas. 0:17:02.800 --> 0:17:05.440 It does squeeze its gas in the middle, but it 0:17:05.680 --> 0:17:08.840 doesn't radiate light like this star of Sundust, did it. 0:17:09.000 --> 0:17:11.840 It does not. You're right, there's a minimum mass in 0:17:11.960 --> 0:17:15.280 order to create the conditions for fusion. Fusion is hard. Remember, 0:17:15.400 --> 0:17:18.359 what you're doing is squeezing together two protons which have 0:17:18.400 --> 0:17:22.000 a pretty powerful force repelling them. Right, they're both positively charged. 0:17:22.040 --> 0:17:24.000 You don't like to get together, So to get the 0:17:24.040 --> 0:17:27.359 protons close enough together to fuse to make helium, you 0:17:27.400 --> 0:17:30.320 have to overcome that. So you got to squeeze them really, 0:17:30.359 --> 0:17:33.840 really hard. And so if you don't have enough gravitational pressure, 0:17:33.880 --> 0:17:36.800 you haven't raised the temperature enough, then fusion just doesn't happen. 0:17:37.160 --> 0:17:40.800 So there's a minimum threshold above which fusion happens and 0:17:40.840 --> 0:17:44.320 below which it doesn't. So Jupiter is below that threshold 0:17:44.400 --> 0:17:46.600 by like a factor of ten. In order to get 0:17:46.640 --> 0:17:49.320 Jupiter to have fusion to ignite at its core, you'd 0:17:49.400 --> 0:17:52.200 have to add like nine more Jupiter's worth of mass 0:17:52.240 --> 0:17:55.159 to get it to that threshold. Red dwarfs are stars 0:17:55.160 --> 0:17:59.320 that are just above that minimum threshold, like eight percent 0:17:59.400 --> 0:18:01.560 of the mass of the Sun. It's like the minimum 0:18:01.600 --> 0:18:04.520 amount of stuff you need to get fusion going. So 0:18:04.640 --> 0:18:08.040 red dwarfs are like basically the smallest fusion reactor you 0:18:08.040 --> 0:18:10.960 can have. So red dwarf is a star in the 0:18:11.000 --> 0:18:13.399 sense that it has fusion inside of it. If you 0:18:13.400 --> 0:18:15.520 don't make it to the threshold fusion, like if you're 0:18:15.560 --> 0:18:19.400 like point ninety ninety nine below the fusion limit, would 0:18:19.440 --> 0:18:20.919 you still glow or did you just be like a 0:18:20.960 --> 0:18:23.760 giant gas planet like Jupiter. You'd be a giant gas 0:18:23.760 --> 0:18:26.600 planet like Jupiter. You wouldn't have fusion, but you would 0:18:26.600 --> 0:18:28.960 still be kind of hot. Even just having that much 0:18:29.000 --> 0:18:31.359 mass and that pressure makes you kind of hot. Like 0:18:31.400 --> 0:18:34.159 the core of Jupiter is not cool, right, it's very 0:18:34.200 --> 0:18:38.000 high density, high temperature, just not high enough to be fusion. Now, 0:18:38.040 --> 0:18:40.280 because you're pretty hot, you are going to glow. You're 0:18:40.320 --> 0:18:43.040 gonna glow very deep in the infrared, and you're not 0:18:43.080 --> 0:18:45.800 going to be nearly as bright as stars that actually 0:18:45.880 --> 0:18:49.440 have fusion happening in them. All right, well, I'll take 0:18:49.480 --> 0:18:53.760 being kind of hot, but not being hot, although being 0:18:53.840 --> 0:18:56.359 cool it's also pretty cool. These stars are really fascinating, 0:18:56.400 --> 0:18:58.560 these red dwarfs, and they're kind of cool. As we say, so, 0:18:58.600 --> 0:19:01.360 they tend to radiate in the red region, and they're 0:19:01.400 --> 0:19:04.320 also really really dim, Like these things are not nearly 0:19:04.359 --> 0:19:07.000 as bright as our sun. As a star gets bigger, 0:19:07.040 --> 0:19:09.840 it gets hotter, and then the fusion happens faster, and 0:19:09.840 --> 0:19:12.040 so they get brighter and brighter, which is why like 0:19:12.200 --> 0:19:15.240 really big massive stars starts like one hundred or two 0:19:15.320 --> 0:19:18.160 hundred times the mass of our sun burn really brightly, 0:19:18.280 --> 0:19:21.359 very blue, and don't last for very long. They can 0:19:21.400 --> 0:19:23.920 burn out just a few million years. Stars that are 0:19:24.040 --> 0:19:27.040 about the size of our sun last for billions of years. 0:19:27.480 --> 0:19:30.679 But if a star is smaller and cooler, it doesn't 0:19:30.720 --> 0:19:33.400 burn as bright, it's much dimmer. It can actually last 0:19:33.640 --> 0:19:36.399 much much longer. So a red dwarf can last for 0:19:36.720 --> 0:19:40.720 longer than the age of the universe, or even much longer. WHOA, 0:19:41.240 --> 0:19:43.520 I guess, because it's got like the heat on low 0:19:43.640 --> 0:19:46.359 basically right, it's like it's got just enough gravity to 0:19:46.560 --> 0:19:49.440 make fusion, but not enough to like burn a lot 0:19:49.480 --> 0:19:51.760 of it, So it's just burning a little bit in 0:19:51.800 --> 0:19:54.399 the center of it like a candle, more like a bonfire, 0:19:54.560 --> 0:19:56.119 and there's something else going on like the heart of 0:19:56.119 --> 0:19:59.240 these red dwarfs. Because they're cooler, the way the heat 0:19:59.240 --> 0:20:01.960 gets mixed around in their core is a little bit 0:20:02.000 --> 0:20:04.959 different than in our star. Like at our star, a 0:20:04.960 --> 0:20:07.880 lot of the heat transfer is what we call radiative transfer. 0:20:08.240 --> 0:20:11.280 Like fusion happens, and photons zoom out and the energy 0:20:11.280 --> 0:20:15.080 gets dispersed through the star towards the outside by radiation. 0:20:15.200 --> 0:20:17.400 Right these photons are flying out and so the outer 0:20:17.480 --> 0:20:20.200 parts of the star get hotter and hotter, and helium 0:20:20.240 --> 0:20:22.879 the fusion product tends to fall towards the core in 0:20:22.960 --> 0:20:25.240 our star, and that's actually a problem for our star 0:20:25.359 --> 0:20:28.400 because that helium tends to sort of put out the fusion, 0:20:28.880 --> 0:20:31.280 and so then fusion only happens on the outside of 0:20:31.280 --> 0:20:33.160 the star. But in a red dwarf it's a little 0:20:33.200 --> 0:20:36.159 bit different. Remember it's not as bright the outside of 0:20:36.160 --> 0:20:37.639 a star. What do you mean for a star like 0:20:37.680 --> 0:20:39.600