WEBVTT - Listener Questions 52 0:00:08.200 --> 0:00:12.320 Hey, Daniel, any aliens yet, not so far, at least 0:00:12.400 --> 0:00:13.319 not that I'm aware of. 0:00:13.560 --> 0:00:16.759 Ooh, do you think they're not hearing your invitations to 0:00:16.800 --> 0:00:17.600 come on the podcast? 0:00:18.440 --> 0:00:20.759 Well, you know, if they're hearing the podcast, maybe that's 0:00:20.800 --> 0:00:22.240 why they're staying away. 0:00:22.280 --> 0:00:26.040 Oh no, are you seeing our podcast? Is keeping humanity 0:00:26.079 --> 0:00:28.720 for making first contact with an alien species? 0:00:29.280 --> 0:00:30.760 It could be. But you know, if they don't like 0:00:30.920 --> 0:00:33.400 dad jokes or bananas or chocolate, do we really want 0:00:33.440 --> 0:00:34.040 to talk to them? 0:00:34.240 --> 0:00:35.920 That's right? They can't be very cool if they don't 0:00:36.000 --> 0:00:38.280 like any of those things. I mean, what are we 0:00:38.280 --> 0:00:39.239 going to talk about with them? 0:00:39.440 --> 0:00:41.479 I know that is in the end the great filter. 0:00:57.480 --> 0:00:57.639 Hi. 0:00:57.640 --> 0:01:00.000 I'm Hori, ma cartoonist and the author of Oliver's Great 0:01:00.240 --> 0:01:00.960 Big Universe. 0:01:01.080 --> 0:01:01.240 Hi. 0:01:01.320 --> 0:01:03.800 I'm Daniel. I'm a particle physicist and a professor a 0:01:03.920 --> 0:01:06.479 uc Ermine, and I live five miles from the most 0:01:06.560 --> 0:01:08.800 famous chocolate covered banana joint. 0:01:08.920 --> 0:01:11.319 Wait what, I didn't know this? What makes it the 0:01:11.360 --> 0:01:12.119 most famous one? 0:01:12.120 --> 0:01:13.600 You've never seen? Arrested Development. 0:01:14.000 --> 0:01:16.520 I've seen the show. I guess I'm not a super fan. 0:01:17.040 --> 0:01:18.839 Is that like a real thing? Like the one featured 0:01:18.880 --> 0:01:19.959 in the show is a real thing? 0:01:20.040 --> 0:01:22.280 Oh? Yes, absolutely, it's a real thing. In fact, there 0:01:22.280 --> 0:01:26.360 are two chocolate covered frozen banana stands on Balbo Island 0:01:26.480 --> 0:01:29.560 near my house, and they both claim to be the original. 0:01:29.720 --> 0:01:31.720 Well one of them is lying. Then, yes, one of 0:01:31.760 --> 0:01:34.800 them is lying, or one of them is wrong at least, 0:01:34.840 --> 0:01:38.360 or maybe they're both wrong. Maybe the original one is 0:01:38.400 --> 0:01:39.840 in New Jersey or something. 0:01:40.120 --> 0:01:43.120 Either way, they're feuding about bananas and chocolate. 0:01:43.200 --> 0:01:45.160 But then, which is one featured in the show that 0:01:45.240 --> 0:01:46.440 must be the most famous one. 0:01:46.920 --> 0:01:48.440 I'm not sure if the one featured in the show 0:01:48.480 --> 0:01:50.000 is one of the real ones, or if it's a 0:01:50.040 --> 0:01:51.240 fictional stand. 0:01:50.960 --> 0:01:54.840 In Oh interesting, So then neither of them is very famous. 0:01:57.960 --> 0:02:00.680 The concept of Newport Beach chocolate covered for as bananas 0:02:00.960 --> 0:02:02.080 is famous. 0:02:02.080 --> 0:02:03.559 Have you tried it? Is it good? 0:02:03.640 --> 0:02:05.040 You know? Not a fan of the bananas. 0:02:05.160 --> 0:02:07.160 Is it worth going to Bubblea Island to have them? 0:02:07.360 --> 0:02:09.160 No? Not a fan of the bananas. Even if you're 0:02:09.200 --> 0:02:10.000 covered in chocolate. 0:02:10.200 --> 0:02:12.680 Wow, what if it's a dark chocolate that's better? 0:02:12.960 --> 0:02:14.720 Definitely better, but not good enough? 0:02:15.560 --> 0:02:17.560 You would stop at the banana like you would eat 0:02:17.600 --> 0:02:20.440 it anything but the banana. 0:02:20.480 --> 0:02:23.799 It's just a chocolate delivery system, exactly the banana's got 0:02:23.800 --> 0:02:24.600 nothing to represent. 0:02:24.760 --> 0:02:26.360 I would have thought it's the food that bring us 0:02:26.360 --> 0:02:30.120 all together. Daniel, It's like this podcast is a chocolate 0:02:30.120 --> 0:02:30.960 covered banana. 0:02:31.040 --> 0:02:32.600 I know, and it's a big joke, so you think 0:02:32.639 --> 0:02:33.160 we'd love it. 0:02:33.200 --> 0:02:36.200 But anyway, speaking of podcasts, welcome to our podcast, Daniel 0:02:36.240 --> 0:02:39.680 and Jorge Explain the Universe, a production of iHeartRadio, in 0:02:39.680 --> 0:02:40.079 which we. 0:02:40.040 --> 0:02:42.880 Try to feed you the secrets of the universe. We 0:02:43.000 --> 0:02:45.320 dip them in chocolate, we freeze them, we do everything 0:02:45.320 --> 0:02:47.960 we can to make them palatable because we think that 0:02:48.040 --> 0:02:50.920 everything that's out there in the universe can be understood 0:02:50.960 --> 0:02:54.399 and deserves to be understood by me and by you 0:02:54.520 --> 0:02:58.160 and by everybody out there. Explanations are possible, and you 0:02:58.200 --> 0:02:59.080 deserve to hear them. 0:02:59.240 --> 0:03:02.600 That's right to hear on this podcast, which is in fact, 0:03:02.639 --> 0:03:06.000 the most popular podcast called Daniel and Jorge Explain the 0:03:06.080 --> 0:03:09.880 Universe that has not been featured in a TV show yet. 0:03:12.720 --> 0:03:15.079 That's true, that's highly qualified, but also accurate. 0:03:17.000 --> 0:03:19.360 It's all the details. You could read the fine prints. 0:03:19.440 --> 0:03:22.200 We're probably also the most successful podcast that mentions the 0:03:22.200 --> 0:03:25.639 word banana so often there might be podcasts dedicated to bananas. 0:03:25.800 --> 0:03:28.040 I feel like you're making an unscientific claim. Have you 0:03:28.080 --> 0:03:31.280 sampled all other podcasts to make that claim? I have not. 0:03:31.360 --> 0:03:34.520 I'm guessing I'm definitely speculating. The first step in science 0:03:34.600 --> 0:03:37.360 is speculating. Right then you go out, you gather some data. 0:03:37.920 --> 0:03:39.560 Let's see, that's your hypothesis. 0:03:39.920 --> 0:03:40.800 I'll follow up on it. 0:03:42.080 --> 0:03:43.440 That's your dull hypothesis. 0:03:45.960 --> 0:03:48.080 Nature is always full of surprises, and so maybe the 0:03:48.160 --> 0:03:49.960 podcast Universe will surprise me. 0:03:50.240 --> 0:03:53.440 We'll see, we'll see. But anyways, we do like to 0:03:53.480 --> 0:03:55.920 take facts about the universe and all the amazing things 0:03:55.920 --> 0:03:58.400 that are happening out there, cover them in delicious chocolate, 0:03:58.440 --> 0:04:00.680 and then tell them to you so that you can 0:04:00.720 --> 0:04:04.520 also appreciate what's out there and the dark mysteries of 0:04:04.600 --> 0:04:05.320 the cosmos. 0:04:05.400 --> 0:04:08.400 But this podcast isn't just us talking about the universe. 0:04:08.440 --> 0:04:11.160 It's a conversation between us and you. We want to 0:04:11.200 --> 0:04:14.080 know what you don't understand about the universe. We'd love 0:04:14.120 --> 0:04:16.520 to know what puzzles you, what you'd like to hear 0:04:16.600 --> 0:04:20.920 more about, and what explanations you find unsatisfactory. So if 0:04:20.960 --> 0:04:23.240 you have questions about how the universe works, or you've 0:04:23.240 --> 0:04:25.279 always heard something explained a certain way and it never 0:04:25.400 --> 0:04:29.160 really clicked. Please write to us to questions at Danielandjorge 0:04:29.320 --> 0:04:31.760 dot com. We will write back to you and help 0:04:31.800 --> 0:04:32.560 you figure it out. 0:04:32.800 --> 0:04:35.200 Yeah, because even though it sort of starts with guessing, 0:04:35.360 --> 0:04:39.480 before guessing comes to questions, right, scientific progress starts with 0:04:39.520 --> 0:04:42.520 somebody looking at something and going, huh, how does that work? 0:04:42.560 --> 0:04:44.560 Why is that the way it is? And can I 0:04:44.680 --> 0:04:46.120 freeze it and cover it in chocolate? 0:04:48.520 --> 0:04:50.880 Every scientific question ends with can I freeze it and 0:04:50.920 --> 0:04:51.719 cover it in chocolate? 0:04:51.839 --> 0:04:56.880 Yes? Can you take a cork, freeze it and covered 0:04:56.920 --> 0:04:58.200 it in dark matter chocolate? 0:04:58.360 --> 0:04:59.919 These are some dark forces we're playing with. 0:05:00.320 --> 0:05:03.320 Yeah, it's a tasty field of research there, but yeah, 0:05:03.320 --> 0:05:05.320 it all starts with questions. And as you said, Daniel, 0:05:05.400 --> 0:05:08.280 we love to take questions from our listeners, and sometimes 0:05:08.320 --> 0:05:11.320 we dedicate whole episodes to answering them, or at least 0:05:11.560 --> 0:05:13.159 trying to answer them. 0:05:13.440 --> 0:05:16.279 To making silly jokes about them. At the very minimum, 0:05:16.520 --> 0:05:18.320 if I get a question that I think, hmm, I 0:05:18.360 --> 0:05:20.120 bet other people want to hear the answer to this, 0:05:20.320 --> 0:05:22.800 or I'm Sureorge has some funny things to say about 0:05:22.839 --> 0:05:25.039 this topic, then instead of just running back to you, 0:05:25.120 --> 0:05:27.599 we will answer it here on the podcast For everybody 0:05:27.640 --> 0:05:27.960 to hear. 0:05:28.240 --> 0:05:29.880 Wait, are you saying there are questions you get and 0:05:29.920 --> 0:05:33.080 you're like, nobody else wants to know the answer. You're like, 0:05:33.160 --> 0:05:37.240 only the person asking this question could possibly be interested 0:05:37.240 --> 0:05:37.839 in this topic. 0:05:37.960 --> 0:05:41.359 Absolutely. People send me their crazy, detailed theories of the 0:05:41.480 --> 0:05:44.960 universe and they want specific answers to why it works 0:05:45.040 --> 0:05:47.560 or doesn't work. That's not the kind of thing we 0:05:47.560 --> 0:05:48.320 talk about on the. 0:05:48.279 --> 0:05:52.080 Podcast, although maybe we should. I don't know. I wonder 0:05:52.080 --> 0:05:54.360 if that would make an interesting episode to get some 0:05:54.440 --> 0:05:56.640 of your theories about the universe that you get and 0:05:56.680 --> 0:05:58.320 then figure out why they're not true. 0:05:58.480 --> 0:06:00.760 Yeah, maybe it would. And if I ever find one 0:06:00.760 --> 0:06:03.360 that is compelling that does sound great, then absolutely we'll 0:06:03.400 --> 0:06:04.520 talk about it on the podcast. 0:06:04.680 --> 0:06:06.960 Or I mean we can. I'll shoot another podcast, you know, 0:06:07.040 --> 0:06:09.479 Daniel and Jorge shoot down your theory of everything. 0:06:10.600 --> 0:06:12.880 Why You're wrong about the universe with Daniel. 0:06:13.320 --> 0:06:17.720 Yes, or just why you're wrong? That's actually a pretty 0:06:17.760 --> 0:06:18.400 good idea there. 0:06:19.000 --> 0:06:21.320 There's a podcast already called wrong about Everything. 0:06:21.440 --> 0:06:23.440 Yeah, but we be the more famous one. 0:06:23.360 --> 0:06:25.760 Yeah, we talk about bananas more than the other one. 0:06:26.080 --> 0:06:30.120 Yeah. We recorded in Bubble Island, which automatically makes it 0:06:30.120 --> 0:06:33.120 more famous. But Anyways, we do like to ask her questions, 0:06:33.120 --> 0:06:41.600 and so today on the podcast, we'll be tackling listener questions. 0:06:41.880 --> 0:06:45.280 Number fifty two. Is fifty two an important number? 0:06:46.480 --> 0:06:48.279 Yeah, it's one more important than fifty one. 0:06:49.600 --> 0:06:52.200 I feel like it has area fifty two connotations. 0:06:52.279 --> 0:06:53.400 Isn't that area fifty one? 0:06:53.640 --> 0:06:57.920 Oh? Is it? No? I'm talking about the extra secret 0:06:57.920 --> 0:07:01.520 area that people don't even know exists. It's the one 0:07:01.560 --> 0:07:02.720 after the area fifty one. 0:07:03.360 --> 0:07:05.440 Make sure you don't tell anyone about Area fifty three. 0:07:05.560 --> 0:07:09.800 That's double extra secret. You need one more level of clearance. 0:07:10.760 --> 0:07:13.400 They know about that, don't tell me because I have 0:07:13.440 --> 0:07:14.440 no security clearance. 0:07:16.800 --> 0:07:18.960 But yeah, we like to answer questions here, and today 0:07:19.000 --> 0:07:22.160 we have three great questions from listeners. One of them 0:07:22.240 --> 0:07:26.240 is about Daniel's favorite topic, aliens. The other one is 0:07:26.320 --> 0:07:29.480 about the electromagnetic force and why it works the way 0:07:29.520 --> 0:07:33.280 it does. And the third one is about saving humanity 0:07:33.640 --> 0:07:36.320 by destroying something that maybe a lot of people. 0:07:36.040 --> 0:07:38.160 Hold, precious chocolate covered bananas. 0:07:38.840 --> 0:07:41.800 Yeah, we'll cover the moon in troublin. All right, Well, 0:07:41.880 --> 0:07:44.800 let's jump right in, Daniel. Our first question comes from Nick, 0:07:44.880 --> 0:07:47.200 who's from Tucson, Arizona. 0:07:47.440 --> 0:07:47.600 Hi. 0:07:47.720 --> 0:07:52.000 Daniel and Jorge. This is Nick from Tucson, Arizona. Growing 0:07:52.080 --> 0:07:54.200 up in a city that is so richly involved in 0:07:54.240 --> 0:07:58.560 science and astronomy, asking questions about our universes become second nature. 0:07:59.160 --> 0:08:03.120 One of the reasons questions I've had is this, in 0:08:03.160 --> 0:08:06.720 our search for life elsewhere in the universe, we see 0:08:06.760 --> 0:08:12.520 abundant evidence that we are likely not alone in the universe. However, 0:08:13.400 --> 0:08:16.360 on the off chance that we actually are, at what 0:08:16.520 --> 0:08:19.880 point do we make that determination? Given one cannot prove 0:08:19.920 --> 0:08:23.720 a negative. I'm excited to hear your breakdown of how 0:08:23.760 --> 0:08:26.920 we tackle such a dilemma. Thanks for being awesome. 0:08:27.400 --> 0:08:30.600 All right, interesting question from Nick here. I feel like 0:08:30.600 --> 0:08:34.280 he's basically asking, how will we ever know whether we're 0:08:34.280 --> 0:08:35.480 alone in the universe or not? 0:08:35.880 --> 0:08:38.680 It's a good question, and I think he's also asking 0:08:39.200 --> 0:08:41.000 what can we say. Is there some point at which 0:08:41.040 --> 0:08:43.840 we draw the line and say we're done looking we've 0:08:43.880 --> 0:08:45.560 decided we're alone. 0:08:45.280 --> 0:08:47.640 Like at some point in the future, if we never 0:08:47.679 --> 0:08:49.480 hear from other aliens and kind have to figure it 0:08:49.520 --> 0:08:51.880 out that maybe we are alone? Right like it nobody 0:08:51.880 --> 0:08:54.600 ever comes to visit you to your house, obviously, the 0:08:54.640 --> 0:08:56.480 answer is that you're the only person on Earth. 0:08:56.640 --> 0:08:59.560 Yeah, or everybody hates you. 0:09:00.840 --> 0:09:05.200 Yeah, that's the explanation. But let's keep diluting ourselves. 0:09:05.640 --> 0:09:08.640 I think this question is really interesting from the philosophical 0:09:08.679 --> 0:09:11.160 point of view, like how could you ever know whether 0:09:11.160 --> 0:09:14.160 we're alone? And also it reveals something about how we 0:09:14.200 --> 0:09:17.880 make statements in science, how you can make statistical arguments 0:09:17.920 --> 0:09:20.440 even if you can't ever make definitive arguments. 0:09:20.640 --> 0:09:23.320 Well, Nick brings up the idea that it's impossible to 0:09:23.400 --> 0:09:27.200 prove a negative right. It's technically theoretically possible to say, 0:09:27.200 --> 0:09:29.400 for example, that there are no pink unicorns out there 0:09:29.400 --> 0:09:32.200 in the universe, because there might be, and so you'd 0:09:32.240 --> 0:09:34.840 have to check every little nuk and cranny of the 0:09:35.000 --> 0:09:38.160 entire cosmos to be able to say that such a 0:09:38.200 --> 0:09:40.000 unicorn does not exist exactly. 0:09:40.080 --> 0:09:43.040 And even checking every little nuok and cranny the last 0:09:43.080 --> 0:09:46.800 cosmos doesn't prove it right, especially in a case of aliens, 0:09:46.800 --> 0:09:49.800 where the category is so broad and undefined. It's basically 0:09:50.120 --> 0:09:53.120 any sension being that doesn't come from Earth. You could 0:09:53.120 --> 0:09:55.679 have lots of different characteristics that we don't anticipate. You 0:09:55.760 --> 0:09:58.240 might imagine, oh, if we check every single planet out 0:09:58.240 --> 0:10:00.960 there and we don't find aliens, then now we're alone, 0:10:01.040 --> 0:10:04.319 but aliens could always exist in some manner we didn't anticipate. 0:10:04.720 --> 0:10:07.600 So yeah, we might not find aliens on rocky planets, 0:10:07.600 --> 0:10:10.079 but they could exist in gas giants or underground, or 0:10:10.080 --> 0:10:12.199 in the center of stars, or in dark matter, or 0:10:12.240 --> 0:10:15.720 in some other way we hadn't imagined. So it's impossible 0:10:15.760 --> 0:10:18.440 to ever say we are totally alone in the universe. 0:10:18.480 --> 0:10:21.280 You can discover aliens, you can meet them and conclude 0:10:21.320 --> 0:10:23.840 that they're there. But you're right that we can't technically 0:10:23.880 --> 0:10:26.320 say definitively that we are alone. 0:10:26.440 --> 0:10:29.240 Right, ever, Right, Like, it's theoretically impossible. 0:10:29.280 --> 0:10:33.000 It's theoretically impossible to make a completely definitive statement. But 0:10:33.080 --> 0:10:35.760 I also think that's too high a bar. That's not 0:10:35.880 --> 0:10:38.240 the bar we use in science, for example. 0:10:38.160 --> 0:10:40.520 Oh, you mean being correct is too high of a bar. 0:10:41.040 --> 0:10:43.880 Making absolute definitive statements is not the business we're in. 0:10:43.920 --> 0:10:45.959 Right, it's not the business because you can't do it. 0:10:46.080 --> 0:10:46.640 You can't do it. 0:10:46.679 --> 0:10:48.280 You try to do it, you wouldn't be able to do. 0:10:48.240 --> 0:10:51.839 It, Yeah, exactly, And so instead we have statistical tools 0:10:51.840 --> 0:10:54.320 that tell us, like how confident we can be in 0:10:54.360 --> 0:10:58.160 a statement. You could never say anything really definitively, even 0:10:58.200 --> 0:11:01.200 things like the Higgs boson. When we discovered the Higgs boson, 0:11:01.559 --> 0:11:04.640 we claim discovery of it, but we also said, here 0:11:04.679 --> 0:11:07.520 are the chances that we're wrong. Here's the chances that 0:11:07.600 --> 0:11:10.080 the Higgs boson doesn't exist, and it just sort of 0:11:10.160 --> 0:11:11.520 looks like it does right. 0:11:11.600 --> 0:11:14.880 Right. That just kind of gets to how science actually works, 0:11:14.920 --> 0:11:17.840 which is through this idea of the null hypothesis. Right, Like, 0:11:17.880 --> 0:11:20.240 for example, even the Higgs boson, it's not like you 0:11:20.280 --> 0:11:21.920 went out there and you said, well, I have a 0:11:21.960 --> 0:11:24.160 certain degree of confidence of the Higgs boson exists. You're 0:11:24.200 --> 0:11:27.320 actually really what you're saying in your science papers is saying, 0:11:27.679 --> 0:11:31.920 we have a certain degree of confidence that not having 0:11:31.960 --> 0:11:34.200 the Higgs boson is not possible. 0:11:34.440 --> 0:11:38.480 Yeah, we calculate very precisely the probability of having been 0:11:38.559 --> 0:11:41.160 fooled because remember, we don't see the Higgs directly. It's 0:11:41.200 --> 0:11:43.280 not like something we can say, here is one look 0:11:43.360 --> 0:11:45.960 at it. It's not like discovering a unicorn in the forest. 0:11:45.960 --> 0:11:48.720 We only see its footprints and its hair left on trees, 0:11:48.840 --> 0:11:51.440 and we have indirect evidence like we almost always do 0:11:51.600 --> 0:11:54.480 in science, and so we can calculate the probability of 0:11:54.520 --> 0:11:57.800 seeing that indirect evidence without there being a Higgs boson, 0:11:57.840 --> 0:11:59.839 which is not zero, and we could say, well, we 0:12:00.200 --> 0:12:03.440 rule that out, not completely, not definitively, but we can 0:12:03.480 --> 0:12:05.800 say it's very unlikely, and we can be very specific 0:12:06.120 --> 0:12:08.599 about the level at which it's unlikely, and there's a 0:12:08.600 --> 0:12:12.120 standard threshold above which we're allowed to say we've discovered it, 0:12:12.200 --> 0:12:15.840 we've pretty much settled it. But of course it's never definitive. 0:12:16.320 --> 0:12:18.600 Although I wonder if with something like the Higgs boson, 0:12:18.679 --> 0:12:20.640 you maybe you can't say that you've seen one, right, 0:12:20.640 --> 0:12:23.240 Like if you collide something and you see a particle 0:12:23.280 --> 0:12:25.640 fly out of it, then the maybe you could say 0:12:25.640 --> 0:12:27.880 that it is there with a one hundred percent confidence. 0:12:28.040 --> 0:12:29.800 We can never say that with one hundred percent confidence. 0:12:29.840 --> 0:12:31.760 The Higgs boson lasts for like ten to the minus 0:12:31.800 --> 0:12:34.440 twenty three seconds. We can never see. We only see 0:12:34.440 --> 0:12:38.679 what it turns into, unfortunately. But that's the case of discovery, 0:12:38.720 --> 0:12:42.000 which is special and wonderful. We can also play statistical 0:12:42.040 --> 0:12:45.920 games when we don't discover something. We can say, for example, oh, 0:12:45.920 --> 0:12:48.560 there's a new particle. If it did exist, we probably 0:12:48.600 --> 0:12:51.400 would have seen it, and so we can conclude that 0:12:51.480 --> 0:12:54.920 it likely doesn't exist, and that's not getting definitive. It 0:12:54.960 --> 0:12:58.079 could be that we got unlucky or something. But it's 0:12:58.080 --> 0:13:00.280 sort of like, you know, looking for Bigfoot. If you 0:13:00.360 --> 0:13:03.079 look all through the forest and you don't see Bigfoot, 0:13:03.320 --> 0:13:05.559 then you can say, well, Bigfoot might exist, but he's 0:13:05.600 --> 0:13:08.880 got to be pretty rare or pretty sneaky, or got 0:13:08.880 --> 0:13:11.520 some camouflage technique that we didn't think of already. You 0:13:11.559 --> 0:13:14.520 can still make negative statements even if they're not definitive. 0:13:14.840 --> 0:13:16.840 Right, But in the case of like Bigfoot or aliens, 0:13:16.880 --> 0:13:18.920 I feel like, once you see one, then that's one 0:13:19.000 --> 0:13:21.760 hundred percent confidence that they exist, right. I think maybe 0:13:21.840 --> 0:13:25.199 Nick is asking more about the scenario where we don't 0:13:25.240 --> 0:13:27.520 see one. So if we see an alien, then for 0:13:27.559 --> 0:13:30.320 sure we know for one hundred percent with confidence that 0:13:30.760 --> 0:13:34.320 they exist. But if we never see one, at what point, 0:13:34.400 --> 0:13:36.760 I think is next question? Do you say, well, I 0:13:36.800 --> 0:13:37.760 guess they don't exist. 0:13:37.840 --> 0:13:39.400 Yeah, I agree in spirit with what you're saying. I 0:13:39.520 --> 0:13:41.800 just want to put an asterisk there, because even if 0:13:41.800 --> 0:13:44.200 you see an alien, you never know one hundred percent. 0:13:44.320 --> 0:13:47.760 You could be being fooled or whatever. No knowledge really 0:13:47.840 --> 0:13:51.040 is one hundred percent definitive. But in practice we call 0:13:51.120 --> 0:13:53.160 that definitive. There are a case in the past where 0:13:53.160 --> 0:13:55.560 we found things were like, there's no way that this 0:13:55.559 --> 0:13:57.400 could have been faked, and then we you know, we're 0:13:57.440 --> 0:14:00.559 pretty sure dinosaurs are real. For example, nobody takes seriously 0:14:00.600 --> 0:14:02.680 the scenario that dinosaurs are all fake. 0:14:02.920 --> 0:14:05.600 Yeah, Or like a whale, like we know, if we'll 0:14:05.600 --> 0:14:09.000 one hundred percent turnty that whales exist and that whales 0:14:09.040 --> 0:14:09.480 are a thing. 0:14:09.679 --> 0:14:12.840 Yeah, right. I mean technically again, like there's always an 0:14:12.880 --> 0:14:15.280 asterisk there. You never know anything one hundred percent. But 0:14:15.559 --> 0:14:18.680 practically speaking, the probability being fooled they're so small we 0:14:18.720 --> 0:14:21.240 basically call it zero. Yes, you're right, but you're right. 0:14:21.360 --> 0:14:23.840 Nick is focused also on the other scenario. What can 0:14:23.880 --> 0:14:26.280 we learn from not discovering aliens? Is there some point 0:14:26.320 --> 0:14:29.080 at which and so we can make statistical statements like 0:14:29.480 --> 0:14:32.760 we know, if the universe was filled with aliens and 0:14:32.800 --> 0:14:35.880 that were very loud in electromagnetism and travel with stars 0:14:35.960 --> 0:14:38.920 very enthusiastically, we would have seen them already. And so 0:14:39.040 --> 0:14:41.800 by not having seen them, we can say, well, if 0:14:41.800 --> 0:14:44.320 those aliens exist, they must be rare, and we can 0:14:44.400 --> 0:14:46.240 say how rare they have to be for us to 0:14:46.280 --> 0:14:49.360 not see them, So we can make negative statistical statements 0:14:49.400 --> 0:14:50.800 about aliens. 0:14:50.360 --> 0:14:54.880 Or not about aliens, but about scenarios for aliens. Right, Like, 0:14:55.040 --> 0:14:58.400 you're not saying aliens don't exist. You're just saying aliens 0:14:58.480 --> 0:15:01.000 they watch a lot of TV, broad SEV and have 0:15:01.120 --> 0:15:06.240 spaceships that figure out inner Citi travel. Those are maybe 0:15:07.480 --> 0:15:11.040 less likely, although those could still exist, you know, maybe 0:15:11.040 --> 0:15:11.920 they don't like to travel. 0:15:12.160 --> 0:15:15.280 Yeah, exactly. You can imagine a scenario and you say, well, 0:15:15.560 --> 0:15:18.600 what are the chances that if that scenario is real, 0:15:18.920 --> 0:15:21.440 we wouldn't have seen aliens? And so if you imagine 0:15:21.480 --> 0:15:23.920 a scenario where aliens are visiting Earth all the time, 0:15:23.960 --> 0:15:26.560 it's very unlikely that we don't see them, And so 0:15:26.640 --> 0:15:28.560 if we haven't seen them, you can mostly rule that 0:15:28.600 --> 0:15:31.400 scenario out. But there are always other scenarios like maybe 0:15:31.400 --> 0:15:34.720 they can't travel, maybe they're weirder than we imagine, maybe 0:15:34.720 --> 0:15:37.200 they don't care to travel, they don't want to contact us, 0:15:37.320 --> 0:15:40.040 or maybe they all died a billion years ago, or 0:15:40.200 --> 0:15:43.320 they're hiding, or there's always some scenario in which aliens 0:15:43.360 --> 0:15:45.600 could exist and we haven't seen them. 0:15:45.760 --> 0:15:48.000 So basically, if you haven't seen them, there's nothing you 0:15:48.000 --> 0:15:50.520 can say about aliens, because I feel like there's so 0:15:50.560 --> 0:15:54.440 many ifs and possibilities that you're really just starting to, 0:15:54.800 --> 0:15:57.760 you know, make statements based on subjetions that you know, 0:15:57.800 --> 0:15:59.600 you really don't have any information about. 0:15:59.720 --> 0:16:01.360 I think the kind of stuff you can say if 0:16:01.400 --> 0:16:04.240 you don't meet aliens is pretty weak, but not exactly 0:16:04.280 --> 0:16:07.720 nothing like aliens that desperately want to come to Earth 0:16:07.760 --> 0:16:11.080 and have the capabilities to do so, those aliens don't exist, 0:16:11.280 --> 0:16:13.640 Like if they existed, they would be here. So we 0:16:13.640 --> 0:16:17.200 can rule out some scenarios, but the space of possible 0:16:17.240 --> 0:16:20.560 scenarios that we can't rule out is infinite, and it's 0:16:20.720 --> 0:16:23.200 much much bigger than the things we can rule out. 0:16:23.360 --> 0:16:25.680 So like, what fraction of the scenarios have we ruled 0:16:25.680 --> 0:16:28.920 out by not discovering aliens? Basically zero. But that doesn't 0:16:28.920 --> 0:16:31.080 mean there are no scenarios we've ruled out. We've learned 0:16:31.120 --> 0:16:33.280 a little bit by not having met aliens. I see. 0:16:33.320 --> 0:16:35.120 I think what you're saying is that we can sort 0:16:35.120 --> 0:16:40.520 of paint, you know, very subtle shades of rarity about 0:16:40.520 --> 0:16:44.240 the idea or the question of whether aliens exist. But again, 0:16:44.280 --> 0:16:47.200 these are just kind of like shades of statements that 0:16:47.240 --> 0:16:50.600 are you know, based on assumptions, and really nobody knows. 0:16:50.760 --> 0:16:53.160 Really nobody knows, but you can learn something like, for example, 0:16:53.200 --> 0:16:55.160 in our book, we go into some of these scenarios. 0:16:55.600 --> 0:16:58.360 Imagine there's a civilization out there in the galaxy that 0:16:58.440 --> 0:17:02.280 builds self replicating robot robots that go off into space 0:17:02.400 --> 0:17:04.920 and find moons and mine them and make more of them. 0:17:05.160 --> 0:17:07.800 So you can exponential number of these robots because each 0:17:07.800 --> 0:17:09.880 one makes two more, which makes two more, which makes 0:17:09.960 --> 0:17:12.640 two more. And you can ask, like, how long does 0:17:12.680 --> 0:17:16.080 it take before that civilization sends a robot to every 0:17:16.200 --> 0:17:19.760 single planet in the galaxy. The answer is like tens 0:17:19.760 --> 0:17:22.600 of thousands of years. So if the galaxy is billions 0:17:22.600 --> 0:17:25.560 of years old, if that civilization exists, or at least 0:17:25.600 --> 0:17:27.800 one of them, then Earth should have some of those 0:17:27.880 --> 0:17:31.240 robots visiting us. So that hasn't happened, for example, we're 0:17:31.240 --> 0:17:33.840 pretty sure, and so we can say, like, that scenario 0:17:33.960 --> 0:17:36.959 is mostly ruled out. So there are interesting scenarios that 0:17:37.000 --> 0:17:39.760 we can mostly rule out. Though you're right, we're always 0:17:39.760 --> 0:17:42.200 making statistical statements and there's lots of stuff we can't 0:17:42.240 --> 0:17:43.240 rule out. 0:17:43.160 --> 0:17:46.040 Right, and at some point I feel like you're basically 0:17:46.080 --> 0:17:50.280 making invaluable unvaluable statements, Like at some point you're basically saying, well, 0:17:50.320 --> 0:17:52.920 if we haven't seen Superman yet, that means that there 0:17:53.000 --> 0:17:55.719 isn't an alien race out there, and that grew up 0:17:55.760 --> 0:17:58.040 in around the Red Sun that was about to explode, 0:17:58.080 --> 0:17:59.600 and then their parents send at this kid out in 0:17:59.600 --> 0:18:02.520 a space and on Earth. That's something we can say 0:18:02.520 --> 0:18:08.120 about aliens. Yes, because so far we haven't seen Superman yet. 0:18:08.240 --> 0:18:11.160 Yes, that's true. Off the infinite list of possible scenarios, 0:18:11.160 --> 0:18:14.080 we can cross one off the list. That's progress. It's 0:18:14.080 --> 0:18:15.080 still infinitely long. 0:18:15.200 --> 0:18:16.840 No, you can't even cross it out the list. 0:18:17.240 --> 0:18:19.720 You can paint it with a statistical rarity, right, you 0:18:19.720 --> 0:18:20.600 can say that's much. 0:18:20.520 --> 0:18:24.320 Less likely, not even that cat right, I mean, it's statistics. 0:18:24.400 --> 0:18:26.520 So just because you haven't rolled twelve on a die 0:18:26.600 --> 0:18:28.360 doesn't mean that you can't, that's right. 0:18:28.400 --> 0:18:30.000 But if you've rolled the die a lot of times 0:18:30.119 --> 0:18:32.239 you never see twelve, then you can start to make 0:18:32.280 --> 0:18:34.960 statements ill possible. It's still possible, ill possible where you 0:18:34.960 --> 0:18:37.480