1 00:00:08,119 --> 00:00:11,440 Speaker 1: Hey, Daniel, I've got a question for you about aliens. 2 00:00:12,360 --> 00:00:15,000 Speaker 1: Did you meet some aliens? Can you introduce me? I'd 3 00:00:15,000 --> 00:00:17,599 Speaker 1: love to meet some aliens. Well, that's my question. Would 4 00:00:17,640 --> 00:00:20,320 Speaker 1: you believe me if I just told you that I 5 00:00:20,360 --> 00:00:23,119 Speaker 1: think there are aliens here on Earth? Well? Are you 6 00:00:23,200 --> 00:00:25,360 Speaker 1: joking or are you being serious? Well? I mean, would 7 00:00:25,400 --> 00:00:28,560 Speaker 1: I joke about science? Isn't that what this podcast? Is 8 00:00:28,680 --> 00:00:34,360 Speaker 1: you joking about science? Me? Now, I don't think I 9 00:00:34,479 --> 00:00:38,760 Speaker 1: joke about science. I think we are a jostle science. Well, um, 10 00:00:39,240 --> 00:00:43,280 Speaker 1: I think a question of that magnitude of that, you know, 11 00:00:43,360 --> 00:00:46,519 Speaker 1: historical importance, I'd need to see some evidence. Really, you 12 00:00:46,520 --> 00:00:50,960 Speaker 1: wouldn't trust me if I said, hey, I met an alien, 13 00:00:51,000 --> 00:00:53,519 Speaker 1: or I think I know who an alien is. Um, 14 00:00:53,560 --> 00:00:55,279 Speaker 1: I have a lot of confidence in you, but I 15 00:00:55,280 --> 00:00:57,520 Speaker 1: think you know, I need to see some evidence on 16 00:00:57,720 --> 00:00:59,920 Speaker 1: such a big claim and don't take it personally. You know, 17 00:01:00,000 --> 00:01:03,040 Speaker 1: I don't think I believe Stephen Hawking or Neil deGrasse Tyson, 18 00:01:03,240 --> 00:01:06,760 Speaker 1: or you know, anybody on a question of such magnitude. Actually, 19 00:01:06,800 --> 00:01:10,480 Speaker 1: those are the guys that I think are aliens. Okay, 20 00:01:10,680 --> 00:01:28,959 Speaker 1: now you have me convinced I am jorhe I'm the 21 00:01:29,040 --> 00:01:32,600 Speaker 1: creator of DHD Comics and a cartoonist. Hi, I'm Daniel. 22 00:01:32,640 --> 00:01:36,720 Speaker 1: I'm a particle physicist and probably not an alien. Probably 23 00:01:36,880 --> 00:01:39,559 Speaker 1: keep that in mind. Who can really say for sure? 24 00:01:39,720 --> 00:01:41,520 Speaker 1: And together we're the co authors of the book We 25 00:01:41,560 --> 00:01:44,280 Speaker 1: Have No Idea, A Guide to the Unknown Universe, and 26 00:01:44,360 --> 00:01:47,280 Speaker 1: the co host of this podcast, Daniel and Jorge Explained 27 00:01:47,319 --> 00:01:50,600 Speaker 1: the Universe, a production of I Heart Radio. That's right, 28 00:01:50,680 --> 00:01:53,200 Speaker 1: the podcast in which we take you on a journey 29 00:01:53,440 --> 00:01:56,680 Speaker 1: here and there and everywhere to wonder where is their life? 30 00:01:56,760 --> 00:01:59,480 Speaker 1: Who's thinking about the universe? Are we the only ones 31 00:02:00,040 --> 00:02:03,240 Speaker 1: asking our minds out into the vast reaches of empty space, 32 00:02:03,480 --> 00:02:06,360 Speaker 1: wondering who else is out there? Are we alone? Or 33 00:02:06,440 --> 00:02:09,000 Speaker 1: is there somebody else out there thinking about the universe? 34 00:02:09,120 --> 00:02:12,160 Speaker 1: I thought you were gonna launch into Doctor SEUs type 35 00:02:12,480 --> 00:02:15,679 Speaker 1: of Ryan there, But did Doctor So let's write a 36 00:02:15,680 --> 00:02:20,359 Speaker 1: book about aliens. Maybe he was the alien. Maybe that's 37 00:02:20,360 --> 00:02:22,840 Speaker 1: why his books are so good. Now this is the 38 00:02:22,880 --> 00:02:26,080 Speaker 1: podcast in which we tackle big questions with a Doctor 39 00:02:26,160 --> 00:02:29,639 Speaker 1: Seuss sort of mindset, explaining things in simple words. That's right. 40 00:02:29,720 --> 00:02:33,239 Speaker 1: All the places you'll go, all the places will take you. Oh, 41 00:02:33,320 --> 00:02:37,960 Speaker 1: the tentacles you'll meet on aliens who come and visit. Yeah, 42 00:02:38,080 --> 00:02:41,200 Speaker 1: we uh kind of This podcast is a lot about 43 00:02:41,200 --> 00:02:44,679 Speaker 1: our place in the universe, you know, right, And a 44 00:02:44,800 --> 00:02:47,360 Speaker 1: big question is are we alone? Are we the only 45 00:02:47,560 --> 00:02:54,720 Speaker 1: ones thinking and having existential crises and having podcasts in 46 00:02:54,800 --> 00:02:57,960 Speaker 1: this huge universe. It's an amazing question, and it's my 47 00:02:58,080 --> 00:03:00,840 Speaker 1: favorite type of question because does no matter what the 48 00:03:00,919 --> 00:03:05,200 Speaker 1: answer is, it's mind blowing, right, Like, Either we're totally 49 00:03:05,280 --> 00:03:08,760 Speaker 1: alone in the universe trillions and trillions of stars and 50 00:03:08,840 --> 00:03:13,440 Speaker 1: planets and we're the only thinking technological creatures. That's incredible. 51 00:03:13,639 --> 00:03:17,680 Speaker 1: What that means I don't know, but spiritually that's pretty important, right, 52 00:03:18,440 --> 00:03:22,200 Speaker 1: Or we're not and there are thinking aliens out there. 53 00:03:22,560 --> 00:03:26,960 Speaker 1: Life began on other planets, intelligence is possible in other areas, Like, 54 00:03:27,320 --> 00:03:29,680 Speaker 1: that's incredible, and what we could learn from those folks. 55 00:03:30,000 --> 00:03:33,640 Speaker 1: So either answer is incredible, and one day I hope 56 00:03:33,720 --> 00:03:36,640 Speaker 1: humanity will know the answer. They will know whether we 57 00:03:36,680 --> 00:03:39,400 Speaker 1: live in this universe where we're all alone or in 58 00:03:39,520 --> 00:03:42,520 Speaker 1: that universe where we have neighbors, and they're gonna look 59 00:03:42,520 --> 00:03:44,560 Speaker 1: back and wonder, like, Wow, what was it like to 60 00:03:44,560 --> 00:03:48,000 Speaker 1: live before we knew the answer to this really basic question. Yeah, 61 00:03:48,040 --> 00:03:50,760 Speaker 1: they might wonder how could you not know or how 62 00:03:50,800 --> 00:03:53,600 Speaker 1: could you not expect there to be other sentient life 63 00:03:53,600 --> 00:03:55,840 Speaker 1: out there? Yeah, it's incredible and so but here we 64 00:03:55,880 --> 00:03:58,840 Speaker 1: are living in the dark ages of human knowledge, right, 65 00:03:58,960 --> 00:04:02,360 Speaker 1: not knowing whether we are alone, and of course wondering. 66 00:04:02,800 --> 00:04:04,760 Speaker 1: And so that's the kind of question that we wanted 67 00:04:04,760 --> 00:04:07,520 Speaker 1: to ponder today. Are we alone in the universe? Yeah? 68 00:04:07,760 --> 00:04:10,200 Speaker 1: Could there be somebody else out there? What does physics 69 00:04:10,200 --> 00:04:13,560 Speaker 1: say about whether or not aliens could have come to visit? 70 00:04:14,200 --> 00:04:17,320 Speaker 1: So today on the podcast, we'll be tackling the question 71 00:04:22,600 --> 00:04:26,360 Speaker 1: why haven't aliens visited us or you know, at least 72 00:04:26,360 --> 00:04:30,320 Speaker 1: called U or d M, does or sent the text 73 00:04:30,320 --> 00:04:34,159 Speaker 1: message at least you know, let's you know what. Maybe 74 00:04:34,160 --> 00:04:36,960 Speaker 1: they're using Google Plus and they didn't realize they's been canceled. 75 00:04:38,960 --> 00:04:41,159 Speaker 1: That would be a t they were early adopters, but 76 00:04:41,760 --> 00:04:45,080 Speaker 1: it worked against them. Maybe Google, maybe people like Google 77 00:04:45,080 --> 00:04:48,000 Speaker 1: are the aliens and they tried. That's right, they tried. 78 00:04:48,200 --> 00:04:50,920 Speaker 1: That's right. And let's set some assumptions, right, because you 79 00:04:50,960 --> 00:04:53,560 Speaker 1: could talk about this question from lots of different angles. 80 00:04:53,960 --> 00:04:56,760 Speaker 1: But I think we should make two assumptions. One, let's 81 00:04:56,760 --> 00:04:59,680 Speaker 1: assume that there are aliens out there, right, I mean, 82 00:05:00,040 --> 00:05:03,920 Speaker 1: why why do we have to assume it? Well, um, 83 00:05:03,960 --> 00:05:05,760 Speaker 1: I don't know, Maybe I just prefer it. You know, 84 00:05:06,200 --> 00:05:07,920 Speaker 1: it's hard for me to imagine that we live in 85 00:05:07,960 --> 00:05:11,600 Speaker 1: the universe where we are the smartest things in the university. 86 00:05:11,640 --> 00:05:13,880 Speaker 1: You know, that's just difficult to accept. Well, I think 87 00:05:13,920 --> 00:05:17,039 Speaker 1: this is the core of the paradox, you know, the question, 88 00:05:17,320 --> 00:05:19,880 Speaker 1: you know, because you know, we hear a lot from scientists, 89 00:05:19,920 --> 00:05:24,239 Speaker 1: and you know, science people like Neolograsty Tyson and Stephen Hawking, 90 00:05:24,279 --> 00:05:26,960 Speaker 1: perhaps that you know, the universe is so big and 91 00:05:26,960 --> 00:05:30,440 Speaker 1: there's so many stars and so many galaxies out there 92 00:05:30,480 --> 00:05:33,039 Speaker 1: that there must be life out there. But I think, 93 00:05:33,200 --> 00:05:36,560 Speaker 1: you know, probably the everyday person listening to this might 94 00:05:36,560 --> 00:05:39,560 Speaker 1: be thinking, but you know, why haven't we heard from them? 95 00:05:39,600 --> 00:05:43,239 Speaker 1: You know, any kind of radio signal or probe or 96 00:05:43,279 --> 00:05:46,359 Speaker 1: a visit or a postcard something. Um, that's kind of 97 00:05:46,360 --> 00:05:48,680 Speaker 1: the paradox, right, It's like it it seems like we 98 00:05:48,720 --> 00:05:52,719 Speaker 1: should assume aliens exists, but why haven't we heard from them? 99 00:05:52,720 --> 00:05:55,240 Speaker 1: That's right, That's right. That's that's the other question. I 100 00:05:55,240 --> 00:05:59,400 Speaker 1: think the second assumption we should make is that we haven't. Right, 101 00:05:59,680 --> 00:06:02,360 Speaker 1: there's a lot of talk their people say they've seen 102 00:06:02,520 --> 00:06:05,680 Speaker 1: UFOs and maybe pilots see weird stuff over the ocean. 103 00:06:05,839 --> 00:06:09,719 Speaker 1: And there's this ridiculous documentary featuring Bubba Lazar and his 104 00:06:09,800 --> 00:06:13,600 Speaker 1: absurd claims about having worked in an alien you know, 105 00:06:13,800 --> 00:06:18,760 Speaker 1: technology re re engineering base. But he has absolutely no 106 00:06:18,880 --> 00:06:20,640 Speaker 1: evidence to back up any of these claims. That we 107 00:06:20,680 --> 00:06:23,479 Speaker 1: could dissect some of those claims, etcetera. But I think 108 00:06:23,839 --> 00:06:27,400 Speaker 1: it was in the Joe Rogan podcast to right, yeah exactly. 109 00:06:27,600 --> 00:06:30,120 Speaker 1: Netflix paid money for it. Joe Rogan had this guy on, 110 00:06:31,320 --> 00:06:33,719 Speaker 1: but the guy has absolutely no evidence to back up 111 00:06:33,760 --> 00:06:35,039 Speaker 1: any of his claims. So I think you can just 112 00:06:35,040 --> 00:06:37,719 Speaker 1: put him in the same category as lots of other 113 00:06:37,760 --> 00:06:40,480 Speaker 1: folks that have seen something weird, something they don't understand, 114 00:06:41,000 --> 00:06:44,400 Speaker 1: and are maybe not reliable eye witnesses. Right, Well, I 115 00:06:44,400 --> 00:06:46,960 Speaker 1: think this this is kind of the question is should 116 00:06:46,960 --> 00:06:49,320 Speaker 1: you just believe someone who says they saw aliens? Does 117 00:06:49,360 --> 00:06:52,599 Speaker 1: physics say it's impossible and therefore you should pay no 118 00:06:52,680 --> 00:06:55,040 Speaker 1: attention to them, or does physics say that it might 119 00:06:55,080 --> 00:06:58,840 Speaker 1: be possible, in which case you maybe should think about 120 00:06:58,880 --> 00:07:01,280 Speaker 1: it or look into it more. Aren't closely? That's right, 121 00:07:01,680 --> 00:07:04,440 Speaker 1: and that's the question we want to answer. Today's Is 122 00:07:04,440 --> 00:07:07,159 Speaker 1: there a physics reason to say aliens could not have 123 00:07:07,279 --> 00:07:10,240 Speaker 1: come visit. Right, does physics say it's possible for aliens 124 00:07:10,240 --> 00:07:12,840 Speaker 1: to have found us? Or does physics say it's impossible? 125 00:07:13,280 --> 00:07:15,640 Speaker 1: And then you can take your own skepticism if you 126 00:07:15,720 --> 00:07:18,440 Speaker 1: like to, to listen to Bob Lazar's claims or the 127 00:07:18,440 --> 00:07:21,120 Speaker 1: claims of anybody else who who says they've been abducted 128 00:07:21,120 --> 00:07:25,000 Speaker 1: by aliens, has been experimented on by aliens, etcetera. But 129 00:07:25,040 --> 00:07:27,679 Speaker 1: today we're going to focus on that question. Right, could 130 00:07:27,720 --> 00:07:30,320 Speaker 1: aliens have contacted us? Right? Because it could be that 131 00:07:30,400 --> 00:07:34,640 Speaker 1: it's impossible for aliens to have visited us or contact us, right, 132 00:07:34,680 --> 00:07:38,040 Speaker 1: I mean, the universe is so vast and d predictable 133 00:07:38,520 --> 00:07:41,720 Speaker 1: that we you know, it could be impossible for there 134 00:07:41,800 --> 00:07:44,400 Speaker 1: to be other life out there, and it could be 135 00:07:44,400 --> 00:07:48,680 Speaker 1: impossible for them to ever reach us or get to us. Right, 136 00:07:48,800 --> 00:07:51,840 Speaker 1: that's right, And you're just thinking about it momentarily, like 137 00:07:52,200 --> 00:07:54,840 Speaker 1: you know that space is vast, You know that space 138 00:07:54,920 --> 00:07:57,520 Speaker 1: is mostly empty. You know, even if it takes us 139 00:07:57,600 --> 00:08:00,240 Speaker 1: years to get even to the neighboring planet. Right, we've 140 00:08:00,280 --> 00:08:02,040 Speaker 1: got a rocket ship and wanted to fly to Mars. 141 00:08:02,040 --> 00:08:04,240 Speaker 1: That would take years, and so to get to a 142 00:08:04,280 --> 00:08:07,000 Speaker 1: nearby star or do you get to you know, several 143 00:08:07,320 --> 00:08:10,680 Speaker 1: to explore a space of stars that's a significant fraction 144 00:08:10,720 --> 00:08:13,520 Speaker 1: of the galaxy. How long would that take? Is that possible? 145 00:08:13,640 --> 00:08:16,880 Speaker 1: Is the galaxy just too big to explore? That's the 146 00:08:16,960 --> 00:08:19,400 Speaker 1: kind of question we want to dig into today. Right, 147 00:08:20,000 --> 00:08:22,400 Speaker 1: So this is a question probably a lot of people 148 00:08:22,560 --> 00:08:25,080 Speaker 1: maybe think about at least in the back of their 149 00:08:25,120 --> 00:08:29,280 Speaker 1: minds or entertainedly. You know, everyone has seen the Avengers movies. 150 00:08:30,320 --> 00:08:35,280 Speaker 1: They're they're aliens there in Star Wars. In the Avengers 151 00:08:35,320 --> 00:08:37,880 Speaker 1: movies that like, some of the aliens look like raccoons, 152 00:08:38,520 --> 00:08:41,680 Speaker 1: which is that would be weird? Raccoons are like the 153 00:08:41,880 --> 00:08:46,280 Speaker 1: central race of the the universe. Wait wait, hold on, 154 00:08:46,320 --> 00:08:48,560 Speaker 1: are you saying we have been visited by aliens and 155 00:08:48,559 --> 00:08:52,600 Speaker 1: they are eating our garbage? Maybe it's a delicacy for them. 156 00:08:52,760 --> 00:08:56,560 Speaker 1: It's like a tourism. That would be a win win, right, 157 00:08:56,720 --> 00:08:59,960 Speaker 1: we meet aliens, we learned about the physics of the university, 158 00:09:00,080 --> 00:09:04,920 Speaker 1: and we find somebody to finally accept our recycling. Perfect. 159 00:09:05,040 --> 00:09:07,600 Speaker 1: We just have to put up with their pooping in 160 00:09:07,640 --> 00:09:11,360 Speaker 1: your yard or something. And what if they're trash is 161 00:09:11,440 --> 00:09:14,960 Speaker 1: something we love? Right? Like they poop out gold bars 162 00:09:15,040 --> 00:09:19,200 Speaker 1: or something chocolate. Well, would you eat a chocolate bar 163 00:09:19,320 --> 00:09:22,839 Speaker 1: and alien pooped out? Or well you sort of do, right, 164 00:09:22,920 --> 00:09:27,840 Speaker 1: I mean chocolate, cocoa beans are are fermented, right, so 165 00:09:27,880 --> 00:09:30,400 Speaker 1: you're sort of eating a kind of the poop there 166 00:09:30,400 --> 00:09:34,000 Speaker 1: of bacteria. Right, chocolate is fermented. What I think? I 167 00:09:34,000 --> 00:09:37,080 Speaker 1: think they ferment that they ferment cocoa beans like they 168 00:09:37,120 --> 00:09:39,000 Speaker 1: harvest them and then they lead them on the sun. 169 00:09:39,280 --> 00:09:42,600 Speaker 1: They rot a little and then they I could, I could, 170 00:09:42,920 --> 00:09:46,760 Speaker 1: I could be saying physically impossible things. Well, um, I 171 00:09:46,800 --> 00:09:49,760 Speaker 1: don't know about whether cocoa is fermented, but you're right, 172 00:09:49,840 --> 00:09:53,000 Speaker 1: we do consume a lot of products that are fermented, 173 00:09:53,040 --> 00:09:56,640 Speaker 1: which is basically the byproduct of microbial metabolism. So we 174 00:09:56,720 --> 00:10:00,600 Speaker 1: have cheese and bread and beer. We're definitely building up 175 00:10:00,720 --> 00:10:04,360 Speaker 1: my cribial poop all the time, and some of it's delicious. Yeah, 176 00:10:04,480 --> 00:10:10,200 Speaker 1: until he's totally not derailed this conversation. But back to aliens, 177 00:10:10,240 --> 00:10:13,480 Speaker 1: Back to aliens, Back to aliens exactly. And so I 178 00:10:13,520 --> 00:10:17,000 Speaker 1: was wondering what do people think about the possibility, like, 179 00:10:17,280 --> 00:10:19,600 Speaker 1: you know, not just aliens, but like could we explore 180 00:10:19,600 --> 00:10:22,000 Speaker 1: the galaxy? Say we are the aliens? Right, if we 181 00:10:22,080 --> 00:10:25,000 Speaker 1: had a sufficient technology, could we explore the galaxy? How 182 00:10:25,000 --> 00:10:26,959 Speaker 1: would people do it? So I walked around campus that 183 00:10:27,000 --> 00:10:29,400 Speaker 1: you see Irvine, and I asked people that question, not 184 00:10:29,800 --> 00:10:32,360 Speaker 1: do you think aliens have visited us? But what do 185 00:10:32,400 --> 00:10:35,360 Speaker 1: you think is the best way to explore the whole galaxy? 186 00:10:35,400 --> 00:10:37,199 Speaker 1: To think about it for a second, if you were 187 00:10:37,240 --> 00:10:41,560 Speaker 1: in charge of NASA and or humanity, how would you 188 00:10:41,760 --> 00:10:45,240 Speaker 1: direct people to explore the universe? That's right, you have 189 00:10:45,320 --> 00:10:48,480 Speaker 1: an unlimited budget and unlimited time. What's the best way 190 00:10:48,480 --> 00:10:50,760 Speaker 1: to fait to visit every solar system and figure out 191 00:10:51,120 --> 00:10:54,480 Speaker 1: if there are aliens there? To find the raccoon home planet? 192 00:10:54,559 --> 00:10:57,760 Speaker 1: That's right? If you had an unlimited amount of raccoon 193 00:10:57,960 --> 00:11:02,160 Speaker 1: gold poop, what would you do? Here's what people had 194 00:11:02,200 --> 00:11:06,679 Speaker 1: to say, vonouma probes? Where's that? Uh? So it's the 195 00:11:07,000 --> 00:11:10,880 Speaker 1: idea by voneuman and by self replicating your robot. So 196 00:11:10,960 --> 00:11:13,720 Speaker 1: they sent them out in all directions, and then they 197 00:11:13,800 --> 00:11:17,439 Speaker 1: have the blueprint to replicate themselves using raw materials to 198 00:11:17,520 --> 00:11:19,920 Speaker 1: find and then send out other probes. So you keep 199 00:11:19,960 --> 00:11:23,240 Speaker 1: expanding in the swear you can cover the galaxy probably 200 00:11:23,280 --> 00:11:26,480 Speaker 1: and uh the under tousing years or so, and since 201 00:11:26,520 --> 00:11:29,960 Speaker 1: we had like two mc swear right, so that would 202 00:11:29,960 --> 00:11:31,920 Speaker 1: be the I remember someone told me that would be 203 00:11:31,920 --> 00:11:35,160 Speaker 1: the best way to do that through a telescope because 204 00:11:35,160 --> 00:11:38,079 Speaker 1: they'll probably be impossible, right, since it's just so far away. 205 00:11:38,120 --> 00:11:39,920 Speaker 1: I don't know how physically we would be able to 206 00:11:39,960 --> 00:11:43,599 Speaker 1: do that, so just by viewing it through satellites or 207 00:11:43,679 --> 00:11:48,240 Speaker 1: trying to get a really big telescope pretty much, well, 208 00:11:48,600 --> 00:11:51,360 Speaker 1: I need to certainly I'm trying to visit them via 209 00:11:52,120 --> 00:11:56,680 Speaker 1: telescope or other means. Well, I mean you need a rocket. 210 00:11:57,080 --> 00:11:59,880 Speaker 1: I don't know, jeez, that would take a long time. 211 00:12:00,559 --> 00:12:03,520 Speaker 1: I would assume that that would be like years and 212 00:12:03,600 --> 00:12:09,320 Speaker 1: years and years. If there's a means of some kind 213 00:12:09,320 --> 00:12:13,599 Speaker 1: of fassion that might travel, it would be feasible. Otherwise, 214 00:12:13,760 --> 00:12:17,439 Speaker 1: I feel like the it would just be near impossible 215 00:12:17,480 --> 00:12:19,520 Speaker 1: to do that within a lifetime. All right, So what 216 00:12:19,520 --> 00:12:22,080 Speaker 1: do you think of people's answers? Uh? They all sound 217 00:12:22,120 --> 00:12:25,680 Speaker 1: pretty pretty reasonable to me. I mean, somebody said you 218 00:12:25,679 --> 00:12:29,040 Speaker 1: could use empty square or two empty square? Was that? 219 00:12:29,720 --> 00:12:32,160 Speaker 1: Is that a typo or a smire? Is that a 220 00:12:32,200 --> 00:12:34,840 Speaker 1: new theory? No? No, No, that's like you know, maybe 221 00:12:34,920 --> 00:12:37,160 Speaker 1: mc squared is not enough. So we've got to upgrade 222 00:12:38,280 --> 00:12:42,719 Speaker 1: physics squared. I'm gonna wait for five MC squared to 223 00:12:42,720 --> 00:12:45,120 Speaker 1: come out before I get my new physics. Do you 224 00:12:45,200 --> 00:12:46,720 Speaker 1: do you have to upgrade? Do you have to? Um? 225 00:12:47,200 --> 00:12:51,040 Speaker 1: You get new icons on your phone and everything. Yeah, exactly. 226 00:12:51,080 --> 00:12:52,880 Speaker 1: Every time a new theory of physics comes out, I 227 00:12:52,960 --> 00:12:55,480 Speaker 1: have to get a new physics phone. It's because otherwise 228 00:12:55,520 --> 00:12:58,360 Speaker 1: it went is too slow. No, there's some good ideas here. 229 00:12:58,400 --> 00:13:01,240 Speaker 1: I mean some people said, like the just use telescopes, right, 230 00:13:01,280 --> 00:13:03,760 Speaker 1: why do you have to go to every planet? And 231 00:13:03,840 --> 00:13:06,800 Speaker 1: that was really intriguing. Um, And I guess it's true 232 00:13:06,840 --> 00:13:09,319 Speaker 1: that if you had really powerful telescopes, if you could 233 00:13:09,360 --> 00:13:13,520 Speaker 1: really image things like across the galaxy and the one 234 00:13:13,559 --> 00:13:15,280 Speaker 1: way to do it. But you know, you can't see 235 00:13:15,360 --> 00:13:17,640 Speaker 1: the other side of the galaxy because the center of 236 00:13:17,679 --> 00:13:20,240 Speaker 1: the galaxy is in the way right. You can see 237 00:13:20,320 --> 00:13:22,640 Speaker 1: the nearby stars, you can see the rest of the 238 00:13:22,840 --> 00:13:24,320 Speaker 1: arm that we're on in the Milky Way, you can 239 00:13:24,360 --> 00:13:27,079 Speaker 1: see the next arm over, but the center of the 240 00:13:27,160 --> 00:13:30,079 Speaker 1: galaxy is blocking us from the other side. Right. It's 241 00:13:30,080 --> 00:13:32,240 Speaker 1: like we're on one side of Manhattan and you want 242 00:13:32,280 --> 00:13:33,960 Speaker 1: to look to see a little town on the other 243 00:13:34,040 --> 00:13:35,599 Speaker 1: side of Manhattan. You're just not gonna be able to 244 00:13:35,600 --> 00:13:38,800 Speaker 1: see anything I see. You're I think that the idea is, 245 00:13:39,200 --> 00:13:42,040 Speaker 1: why should I go over to my neighbors and shake 246 00:13:42,120 --> 00:13:44,079 Speaker 1: their hands to welcome them to the neighborhood when I 247 00:13:44,120 --> 00:13:47,360 Speaker 1: could choose spy on them with a telescope? Is kind 248 00:13:47,360 --> 00:13:52,199 Speaker 1: of That's right, exactly exactly and uh, And it's true 249 00:13:52,480 --> 00:13:55,719 Speaker 1: that we're developing more and more impressive telescopes and we 250 00:13:55,800 --> 00:13:59,040 Speaker 1: will soon be able to image planets around other stars, 251 00:13:59,120 --> 00:14:01,199 Speaker 1: which will be an in audible moment in the history 252 00:14:01,240 --> 00:14:04,200 Speaker 1: of exploration. I mean, we can see black holes, right, 253 00:14:04,320 --> 00:14:07,319 Speaker 1: and we have seen planets around other stars, right, like 254 00:14:07,400 --> 00:14:10,760 Speaker 1: little blips. Right. We've detected their presence because of their 255 00:14:10,800 --> 00:14:14,160 Speaker 1: gravitational effects and because they dim the light. But imaging 256 00:14:14,240 --> 00:14:16,800 Speaker 1: those planets directly, like seeing the photons that come from 257 00:14:16,840 --> 00:14:18,839 Speaker 1: those planets, so we can tell or is there a 258 00:14:18,960 --> 00:14:21,880 Speaker 1: cloudy atmosphere or is there blue water under it? You 259 00:14:21,920 --> 00:14:23,480 Speaker 1: know that kind of stuff where we're not quite there 260 00:14:23,560 --> 00:14:26,280 Speaker 1: yet though, though that's going to come soon. But even still, 261 00:14:26,360 --> 00:14:29,080 Speaker 1: even if you had incredible telescopes, there's a limit because 262 00:14:29,120 --> 00:14:31,400 Speaker 1: you just can't see the rest of the galaxy from here, 263 00:14:31,400 --> 00:14:34,160 Speaker 1: because the center of the galaxy is such a crazy blob. 264 00:14:34,200 --> 00:14:37,000 Speaker 1: There's a black hole there, the zillions of stars, this 265 00:14:37,160 --> 00:14:39,560 Speaker 1: gas and dust. So if you really wanted to be thorough, 266 00:14:39,640 --> 00:14:41,280 Speaker 1: telescopes are not going to get you all the way 267 00:14:41,320 --> 00:14:45,880 Speaker 1: around the galaxy. Well. Also, would it be satisfying, you know, 268 00:14:46,200 --> 00:14:51,080 Speaker 1: just to to see other alien filications, but not talk 269 00:14:51,200 --> 00:14:54,280 Speaker 1: to them and or exchange information with them? Would that 270 00:14:54,400 --> 00:14:57,400 Speaker 1: be satisfying? Not for me? I mean if we used 271 00:14:57,440 --> 00:15:00,480 Speaker 1: our telescopes and found an exoplanet that was fairly nearby, 272 00:15:00,600 --> 00:15:03,520 Speaker 1: you know, tens of light years or something, and we 273 00:15:03,640 --> 00:15:06,200 Speaker 1: saw aliens there, Oh my gosh, we'd have to send something. 274 00:15:06,240 --> 00:15:09,280 Speaker 1: We'd have to send a delegation because otherwise the conversation 275 00:15:09,360 --> 00:15:12,920 Speaker 1: would take forever. I mean, say it's twenty light years away, right, 276 00:15:13,000 --> 00:15:16,480 Speaker 1: then every step of the conversation is forty years, right 277 00:15:16,720 --> 00:15:19,760 Speaker 1: they say, huh, Let me say what you say? Huh, 278 00:15:20,240 --> 00:15:23,600 Speaker 1: that's sixty years gone by, you know. Um, So that 279 00:15:23,600 --> 00:15:26,200 Speaker 1: would be crazy. That would be a pretty slow If 280 00:15:26,240 --> 00:15:28,080 Speaker 1: you looked in out your window and you saw your 281 00:15:28,400 --> 00:15:30,680 Speaker 1: neighbors were having a huge raccoon party, you can go 282 00:15:30,720 --> 00:15:32,480 Speaker 1: over and knock on the doorway. No, I would send 283 00:15:32,560 --> 00:15:36,480 Speaker 1: him a letter and wait thirty three years, like, hey, 284 00:15:36,520 --> 00:15:38,440 Speaker 1: look they have a chocolate fountain at that party, let's 285 00:15:38,440 --> 00:15:43,320 Speaker 1: go over there. Um. But I think you know that 286 00:15:43,480 --> 00:15:45,720 Speaker 1: with the takeaways that there are a lot of ways 287 00:15:45,800 --> 00:15:48,000 Speaker 1: that we could explore the galaxy out there, right, We 288 00:15:48,120 --> 00:15:52,320 Speaker 1: could be seeing things out there, or sending signals or 289 00:15:52,440 --> 00:15:55,880 Speaker 1: sending probes, or getting on ships and taking off and 290 00:15:55,960 --> 00:15:59,080 Speaker 1: sending humans out there. And so if you flip it around, 291 00:15:59,160 --> 00:16:02,040 Speaker 1: the question is kind to like have other aliens done that? 292 00:16:02,480 --> 00:16:05,320 Speaker 1: Or or why haven't they done that? Yeah? Exactly why 293 00:16:05,400 --> 00:16:07,840 Speaker 1: haven't they done that? Because again, we're assuming we have 294 00:16:07,960 --> 00:16:10,440 Speaker 1: not been visited by secretive aliens that have taken over 295 00:16:10,480 --> 00:16:14,560 Speaker 1: the government and are infiltrating the highest levels of power. 296 00:16:15,040 --> 00:16:16,920 Speaker 1: Who we are assuming that nobody has come to visit, 297 00:16:17,200 --> 00:16:19,880 Speaker 1: And so then the question is why not? Right, if 298 00:16:19,960 --> 00:16:22,680 Speaker 1: the life, if the galaxy is teeming with life, why 299 00:16:22,760 --> 00:16:25,760 Speaker 1: have we not been visited or contacted? So I thought 300 00:16:25,800 --> 00:16:28,840 Speaker 1: that the first question might be like, well, you know, 301 00:16:28,920 --> 00:16:32,840 Speaker 1: why would they come here? You know, so what if 302 00:16:32,880 --> 00:16:34,760 Speaker 1: they know that we're here? What if they hear one 303 00:16:34,840 --> 00:16:37,600 Speaker 1: of our messages? Because you know, we've been broadcasting television 304 00:16:37,640 --> 00:16:41,080 Speaker 1: and radio for decades and decades, so it's possible, even 305 00:16:41,120 --> 00:16:44,600 Speaker 1: without intentionally trying to contact the aliens, that we've made 306 00:16:44,600 --> 00:16:47,160 Speaker 1: our presence known. It's kind of like, why would they 307 00:16:47,240 --> 00:16:49,880 Speaker 1: even come to Earth at all? Out of all the 308 00:16:49,960 --> 00:16:53,000 Speaker 1: billions of planets, why would they come to ours? Besides 309 00:16:53,120 --> 00:17:00,840 Speaker 1: the excellent trash that we have, really five star trash here, 310 00:17:00,840 --> 00:17:03,560 Speaker 1: I'm sure in the Michelin Guide to the Galaxy, Earth 311 00:17:03,640 --> 00:17:07,760 Speaker 1: ranks very high in the quality of our garbage. But yeah, exactly. 312 00:17:07,760 --> 00:17:09,560 Speaker 1: And so I thought, well, there is one way we've 313 00:17:09,600 --> 00:17:12,360 Speaker 1: made ourselves known, and that's through these messages to television 314 00:17:12,440 --> 00:17:14,800 Speaker 1: or radio broadcasts. So I thought, well, let's do a 315 00:17:14,840 --> 00:17:18,879 Speaker 1: little calculation, like is there time for those messages to 316 00:17:18,960 --> 00:17:22,840 Speaker 1: have gone out into the galaxy been received by aliens, 317 00:17:23,119 --> 00:17:25,640 Speaker 1: and have them have a chance to come back and visit? 318 00:17:25,760 --> 00:17:29,280 Speaker 1: Like should we have expected to be visited because of 319 00:17:29,400 --> 00:17:31,760 Speaker 1: the radio and TV broadcast that we've been sending out 320 00:17:31,840 --> 00:17:34,600 Speaker 1: inadvertently into space, right? Or when can we expect people 321 00:17:34,720 --> 00:17:41,040 Speaker 1: to hear our our nineteen fifties television right? That's right, exactly. 322 00:17:41,200 --> 00:17:43,320 Speaker 1: And you know some of us have sent messages into 323 00:17:43,400 --> 00:17:46,640 Speaker 1: space specifically, right, Like we used the air CBO radio 324 00:17:46,680 --> 00:17:49,520 Speaker 1: telescope to send a message back in response to the 325 00:17:49,840 --> 00:17:52,600 Speaker 1: wild signal that we got in in seventy seven. That's 326 00:17:52,680 --> 00:17:56,480 Speaker 1: very sporadic. Mostly we've just been broadcasting random stuff and 327 00:17:56,600 --> 00:18:00,040 Speaker 1: that just sends goes out into into interstellar space. So 328 00:18:00,040 --> 00:18:01,879 Speaker 1: if you had a really fine telescope, you might pick 329 00:18:01,920 --> 00:18:05,480 Speaker 1: it up, but of course physics limits us. Right those 330 00:18:05,600 --> 00:18:08,720 Speaker 1: messages have not penetrated the whole galaxy. We've only been 331 00:18:08,720 --> 00:18:11,920 Speaker 1: broadcasting for you know, maybe a hundred years, and so 332 00:18:12,280 --> 00:18:15,359 Speaker 1: you imagine a sphere that's just a hundred light years 333 00:18:15,440 --> 00:18:19,480 Speaker 1: around centered to the Earth. That's a tiny, tiny fraction 334 00:18:19,960 --> 00:18:22,400 Speaker 1: of the galaxy, which you remember is a hundred thousand 335 00:18:22,520 --> 00:18:27,640 Speaker 1: light years across to our radius of influence right now, 336 00:18:27,960 --> 00:18:31,640 Speaker 1: is pretty small. Like the idea that an alien heard 337 00:18:31,720 --> 00:18:33,760 Speaker 1: us and then came to visit us and we haven't 338 00:18:33,840 --> 00:18:37,879 Speaker 1: noticed it seems unlikely because who there's nobody could have 339 00:18:37,920 --> 00:18:40,240 Speaker 1: heard our message yet so far. Well, that was the 340 00:18:40,320 --> 00:18:43,439 Speaker 1: question I had, is how many how many planets are 341 00:18:43,480 --> 00:18:45,639 Speaker 1: there out there that could have heard our message and 342 00:18:45,800 --> 00:18:47,840 Speaker 1: had a chance to build a ship and come visit us. 343 00:18:48,640 --> 00:18:51,879 Speaker 1: So I did a little bit of calculation, and I said, well, 344 00:18:52,000 --> 00:18:54,119 Speaker 1: what if you know, how fast could they get here? 345 00:18:54,200 --> 00:18:56,719 Speaker 1: Let's not assume that they have faster than light travel, right, 346 00:18:56,800 --> 00:18:59,680 Speaker 1: Let's use physics. So assume that they traveled like half 347 00:18:59,760 --> 00:19:02,159 Speaker 1: this beat of light, which seems pretty reasonable, which is 348 00:19:02,240 --> 00:19:05,119 Speaker 1: pretty fast. That's still pretty fast, right, Yeah, that's pretty 349 00:19:05,240 --> 00:19:07,840 Speaker 1: that's pretty zippy. So then if we have a hundred 350 00:19:07,960 --> 00:19:11,119 Speaker 1: years since we broadcast the first message, then sort of 351 00:19:11,160 --> 00:19:14,600 Speaker 1: the outer shell that's fear would actually be like thirty 352 00:19:14,640 --> 00:19:17,840 Speaker 1: three light years away, right, people a hundred light years away. 353 00:19:17,880 --> 00:19:20,440 Speaker 1: They're just now getting the messages we sent a hundred 354 00:19:20,520 --> 00:19:22,600 Speaker 1: years ago, so we could expect to see them in 355 00:19:22,640 --> 00:19:26,719 Speaker 1: two are the ones thirty three light years away? They 356 00:19:26,840 --> 00:19:29,880 Speaker 1: got the message sixty six years ago, so in principle, 357 00:19:30,400 --> 00:19:33,680 Speaker 1: they could have gotten on a ship, immediately pointed it 358 00:19:33,680 --> 00:19:36,040 Speaker 1: in our direction, been traveling a half the speed of 359 00:19:36,119 --> 00:19:38,840 Speaker 1: light for sixty six years, and arrived today, right, meaning 360 00:19:38,920 --> 00:19:42,200 Speaker 1: like they were ready to go. They had the car 361 00:19:42,480 --> 00:19:44,960 Speaker 1: warmed up in the garage, spaceship warmed up. They're like, oh, 362 00:19:45,000 --> 00:19:48,840 Speaker 1: we gotta let's go. That's right. Maybe they have like 363 00:19:48,880 --> 00:19:51,280 Speaker 1: a trash crisis on their planet. They're like, we desperately 364 00:19:51,320 --> 00:19:53,520 Speaker 1: need more trash. And then you know, they hear our 365 00:19:53,560 --> 00:19:55,320 Speaker 1: message and they're like, ah ha, this is what we 366 00:19:55,400 --> 00:19:58,040 Speaker 1: were waiting for. And then they just head out to 367 00:19:58,400 --> 00:20:00,520 Speaker 1: do a trash more like this. Think fan, that guy's 368 00:20:00,960 --> 00:20:05,800 Speaker 1: super hilarious. Let's go meet him. Yeah, exactly. And so 369 00:20:06,240 --> 00:20:09,480 Speaker 1: that's sort of the sphere of possibility. Anybody within thirty 370 00:20:09,560 --> 00:20:12,920 Speaker 1: three light years could have heard our messages and had time, 371 00:20:13,320 --> 00:20:15,919 Speaker 1: you know, given some assumptions that they have the technology, 372 00:20:16,000 --> 00:20:19,280 Speaker 1: that they're interested, etcetera, to come and visit us. So 373 00:20:19,440 --> 00:20:21,920 Speaker 1: then that seems kind of small. Thirty three light years, 374 00:20:21,960 --> 00:20:23,720 Speaker 1: it does seem kind of small, I mean compared to 375 00:20:23,760 --> 00:20:26,240 Speaker 1: the galaxy. But so then I thought, well, how many 376 00:20:26,400 --> 00:20:28,680 Speaker 1: how many planets are there out there? And so I 377 00:20:28,720 --> 00:20:32,440 Speaker 1: actually looked up how many stars there are within a 378 00:20:32,520 --> 00:20:34,520 Speaker 1: certain number of light years and it did a calculation, 379 00:20:34,640 --> 00:20:36,320 Speaker 1: and what did you find. It turns out that there's 380 00:20:36,480 --> 00:20:40,359 Speaker 1: a few hundred stars within that sphere, right, and we 381 00:20:40,560 --> 00:20:45,400 Speaker 1: know that about twenty of stars have an earth like planet. 382 00:20:45,800 --> 00:20:47,840 Speaker 1: Now that depends exactly on the kind of star. But 383 00:20:47,920 --> 00:20:50,800 Speaker 1: let's be generous, so ballparking, you know, And this is 384 00:20:50,840 --> 00:20:52,240 Speaker 1: what we do in physics. We're just like trying to 385 00:20:52,280 --> 00:20:54,240 Speaker 1: get the answer to within the factor of five. Again, 386 00:20:55,440 --> 00:21:01,240 Speaker 1: precision physics right there. Well, you know, decision six out 387 00:21:01,280 --> 00:21:06,320 Speaker 1: of a quarters plus or minus seven ten dollars. Here's 388 00:21:06,359 --> 00:21:11,280 Speaker 1: two dollars. That's pretty enough. Did you say it was 389 00:21:11,320 --> 00:21:14,560 Speaker 1: gonna cost ten billion oops to cost a hundred billions? Sorry? No. 390 00:21:14,920 --> 00:21:16,560 Speaker 1: In physics we do this a lot. We say, well, 391 00:21:16,640 --> 00:21:18,760 Speaker 1: we don't know. This is a really hard problem. We 392 00:21:18,840 --> 00:21:21,080 Speaker 1: don't know the answer precisely. Can we get a rough 393 00:21:21,280 --> 00:21:22,960 Speaker 1: estimate of it? You know, can we figure out, you know, 394 00:21:23,119 --> 00:21:25,920 Speaker 1: to within a factor of two or five ish roughly 395 00:21:25,960 --> 00:21:28,480 Speaker 1: with the back of the envelope and back of the 396 00:21:28,560 --> 00:21:32,840 Speaker 1: envelope exactly and so approximately fifty is the answer we 397 00:21:32,920 --> 00:21:36,240 Speaker 1: expected to be about fifty Earth like planets in that 398 00:21:36,480 --> 00:21:39,960 Speaker 1: sphere where our messages have had time to arrive and 399 00:21:40,160 --> 00:21:42,200 Speaker 1: there's been time for them to turn around and come 400 00:21:42,280 --> 00:21:45,800 Speaker 1: visit us. Interesting, fifty seems that it's a reasonable number, 401 00:21:45,880 --> 00:21:48,920 Speaker 1: isn't it like if you had fifty earths, you know, 402 00:21:49,119 --> 00:21:54,320 Speaker 1: surely some of them might have people on them and listening. 403 00:21:54,600 --> 00:21:57,240 Speaker 1: That's exactly the question. We don't know. We don't know 404 00:21:57,760 --> 00:22:00,560 Speaker 1: what fraction of earthlike planets have life on them? Is it? 405 00:22:02,119 --> 00:22:04,600 Speaker 1: Is it one in fifty, is it one in fifty trillion? 406 00:22:04,960 --> 00:22:08,160 Speaker 1: Or is it one over infinity right as an only Earth. 407 00:22:08,680 --> 00:22:11,280 Speaker 1: And so the fascinating thing about doing these measurements is 408 00:22:11,320 --> 00:22:14,960 Speaker 1: that we've learned something. We know it's not right because 409 00:22:15,440 --> 00:22:17,600 Speaker 1: there are fifty planets out there that have received our 410 00:22:17,640 --> 00:22:21,280 Speaker 1: messages and had time to come, and they haven't. So 411 00:22:21,520 --> 00:22:24,840 Speaker 1: that means that the rate at which earthlike planets have 412 00:22:25,440 --> 00:22:29,879 Speaker 1: intelligent technological aliens that are interested in visiting us is 413 00:22:30,080 --> 00:22:32,720 Speaker 1: less than one in fifty. Say that again, what's that's 414 00:22:32,840 --> 00:22:35,399 Speaker 1: the disc There are fifty planets out there that have 415 00:22:35,520 --> 00:22:38,840 Speaker 1: received our messages. Fifty earthlike planets have received our messages 416 00:22:39,080 --> 00:22:41,040 Speaker 1: and none of them have come to visit us. So 417 00:22:41,200 --> 00:22:44,200 Speaker 1: that means that the rate at which earthlike planets have 418 00:22:44,560 --> 00:22:48,080 Speaker 1: technological aliens that are interested in visiting us and willing 419 00:22:48,119 --> 00:22:50,359 Speaker 1: to take the trip is less than one in fifty. 420 00:22:51,480 --> 00:22:53,520 Speaker 1: That's assuming that someone would get the signal, jump on 421 00:22:53,560 --> 00:22:56,359 Speaker 1: a rocket ship and come over. Yeah, exactly right. So 422 00:22:56,640 --> 00:22:59,120 Speaker 1: with all those assumptions, the answers is, you know, less 423 00:22:59,119 --> 00:23:01,520 Speaker 1: than one in fifty, and so that starts to answer 424 00:23:01,560 --> 00:23:03,680 Speaker 1: the question, right, We know it's not a percent. We 425 00:23:03,720 --> 00:23:06,880 Speaker 1: know that not every earthlike planet out there has technological 426 00:23:06,960 --> 00:23:09,520 Speaker 1: aliens desperate to visit us. Oh, I see, you're flipping 427 00:23:09,560 --> 00:23:11,880 Speaker 1: it around a little bit, right, You're you're using these 428 00:23:11,920 --> 00:23:16,240 Speaker 1: back of the envelope calculations to say, you know, if 429 00:23:16,280 --> 00:23:18,000 Speaker 1: we are going to get visited by aliens, that means 430 00:23:18,040 --> 00:23:19,600 Speaker 1: that they jumped on a ship when they heard us 431 00:23:19,640 --> 00:23:21,680 Speaker 1: and came to look for us. And so if we 432 00:23:21,760 --> 00:23:25,080 Speaker 1: haven't already, that means that probably none of these fifty 433 00:23:25,119 --> 00:23:29,440 Speaker 1: planets have such a civilization. Exactly, if if every single 434 00:23:29,480 --> 00:23:33,480 Speaker 1: earthlike planet out there had trash eating raccoons desperate to 435 00:23:33,520 --> 00:23:36,479 Speaker 1: visit us, then they would have come because there's been 436 00:23:36,520 --> 00:23:39,160 Speaker 1: time for them to do it. So because we haven't 437 00:23:39,200 --> 00:23:43,159 Speaker 1: been visited, therefore, not every earthlike planet is filled with 438 00:23:43,440 --> 00:23:52,600 Speaker 1: technologically advanced trash eating raccoons or other animals. Yeah, so 439 00:23:52,760 --> 00:23:55,520 Speaker 1: other similar aliens. And you know, there's there's a sequence 440 00:23:55,520 --> 00:23:58,360 Speaker 1: of assumptions built into their. Right, they have to be technological, 441 00:23:58,720 --> 00:24:02,280 Speaker 1: they have to use radio, they have to be interested, right, 442 00:24:03,440 --> 00:24:05,680 Speaker 1: they have to be willing all these things. But we 443 00:24:05,800 --> 00:24:08,879 Speaker 1: have learned something, right, we have learned something about what 444 00:24:09,080 --> 00:24:11,800 Speaker 1: aliens are not out there? Right, No, I see, So 445 00:24:12,400 --> 00:24:15,639 Speaker 1: we're ruling out sort of a class of aliens based 446 00:24:15,680 --> 00:24:19,080 Speaker 1: on what hasn't happened yet, that's right, that's right exactly, Okay, 447 00:24:19,400 --> 00:24:22,720 Speaker 1: And every year that number gets smaller, right, because every 448 00:24:22,840 --> 00:24:27,359 Speaker 1: year our radioways go out further, and every year that 449 00:24:27,440 --> 00:24:30,160 Speaker 1: means there are Every year that we don't have aliens 450 00:24:30,240 --> 00:24:33,600 Speaker 1: visitors means that it's less likely that there are aliens 451 00:24:33,680 --> 00:24:36,000 Speaker 1: like that exactly every year we don't get visited. If 452 00:24:36,040 --> 00:24:38,359 Speaker 1: next year they arrived, then boom, the number goes up. 453 00:24:42,760 --> 00:24:46,040 Speaker 1: Every year that we that that our sphere of influence 454 00:24:46,080 --> 00:24:50,080 Speaker 1: expands without being contacted, then we know we we have 455 00:24:50,200 --> 00:24:53,280 Speaker 1: a better and lower estimate of the rate at which 456 00:24:53,400 --> 00:24:58,960 Speaker 1: there are again technological, intelligent aliens interested in willing to 457 00:24:59,040 --> 00:25:01,119 Speaker 1: come and visit it. That are answering in any of 458 00:25:01,160 --> 00:25:04,000 Speaker 1: those assumptions, right, It could be that all those planets 459 00:25:04,080 --> 00:25:06,639 Speaker 1: have aliens, but they're not intelligent, or they're intelligent but 460 00:25:06,680 --> 00:25:10,040 Speaker 1: they're not technological, or they're intelligent and technological but they're 461 00:25:10,040 --> 00:25:12,840 Speaker 1: snobs and they're just not interested in coming to visit us, right, right. 462 00:25:12,960 --> 00:25:15,439 Speaker 1: Or sometimes you know, people have like forty seven thousand 463 00:25:15,520 --> 00:25:17,760 Speaker 1: emails in their inbox and they just can't wait, are 464 00:25:17,800 --> 00:25:19,960 Speaker 1: we talking about aliens? Now? We're talking about you I'm 465 00:25:20,040 --> 00:25:23,040 Speaker 1: just saying, sometimes it happens, you know, it's it's a 466 00:25:23,160 --> 00:25:25,720 Speaker 1: totally human thing too. Well, what I like is that 467 00:25:25,800 --> 00:25:28,960 Speaker 1: you're already empathizing with the aliens. You know, you're reaching out, 468 00:25:28,960 --> 00:25:31,440 Speaker 1: you're saying, I get you, I understand, I have a 469 00:25:31,520 --> 00:25:35,800 Speaker 1: I have a full inbox too. That's right, that's right anyway. 470 00:25:35,840 --> 00:25:39,000 Speaker 1: So that's the sort of scenario if they hear our messages. 471 00:25:39,560 --> 00:25:42,119 Speaker 1: But what if they don't, you know, like, yeah, they 472 00:25:42,160 --> 00:25:44,240 Speaker 1: doesn't have to be that they hear our messages. It 473 00:25:44,320 --> 00:25:47,120 Speaker 1: could be that they're like Star Trek, they're just out 474 00:25:47,119 --> 00:25:49,480 Speaker 1: there exploring, you know, they don't have to necessarily know 475 00:25:49,600 --> 00:25:52,560 Speaker 1: we're here to stumble across us. All right, Let's get 476 00:25:52,600 --> 00:25:56,840 Speaker 1: into another type of alien, which might find is just randomly. Right, 477 00:25:56,920 --> 00:25:59,320 Speaker 1: that's what you're saying. They're just out out and about 478 00:25:59,400 --> 00:26:01,280 Speaker 1: and they find it. So what are the likely what's 479 00:26:01,280 --> 00:26:04,800 Speaker 1: the likelihood that they'll stumble upon us like Columbus stumbled 480 00:26:04,840 --> 00:26:11,640 Speaker 1: upon the Native Americans, which is a great scenario for us. Yeah, 481 00:26:11,880 --> 00:26:14,000 Speaker 1: well for lots of reasons because of how well that 482 00:26:14,080 --> 00:26:16,800 Speaker 1: went for the Native Americans. But also if they arrive 483 00:26:17,040 --> 00:26:19,320 Speaker 1: and they happen to look just like us, then that 484 00:26:19,359 --> 00:26:21,600 Speaker 1: would be quite interesting. All right, let's get into that, 485 00:26:21,720 --> 00:26:36,600 Speaker 1: but first let's take a quick break. All right, we're 486 00:26:36,600 --> 00:26:39,119 Speaker 1: talking about aliens and how likely they are to have 487 00:26:39,400 --> 00:26:42,879 Speaker 1: visited us. So now we're exploring this scenario of what 488 00:26:43,000 --> 00:26:46,440 Speaker 1: are the chances that aliens have could have or could 489 00:26:46,960 --> 00:26:49,720 Speaker 1: stumble upon us. Meaning they're out and about exploring the 490 00:26:49,800 --> 00:26:52,200 Speaker 1: galaxy and they're like, oh, hey, here's a planet with 491 00:26:52,359 --> 00:26:56,040 Speaker 1: some cute little um water bags that move around and 492 00:26:56,119 --> 00:27:00,280 Speaker 1: have podcasts exactly, and there's sort of too compe heating 493 00:27:00,320 --> 00:27:02,440 Speaker 1: things going on from the physics point of view. On 494 00:27:02,680 --> 00:27:06,040 Speaker 1: one hand, the galaxy is huge. It's a hundred thousand 495 00:27:06,119 --> 00:27:09,399 Speaker 1: light years across. It has billions and billions of stars, 496 00:27:09,800 --> 00:27:12,440 Speaker 1: so it seems sort of unimaginable to be able to 497 00:27:12,560 --> 00:27:15,480 Speaker 1: explore it to check every solar system. Right. On the 498 00:27:15,600 --> 00:27:18,399 Speaker 1: other hand, the galaxy is very old. So even though 499 00:27:18,480 --> 00:27:20,840 Speaker 1: the speed of light limits how fast you can zoom 500 00:27:20,880 --> 00:27:23,879 Speaker 1: between stars, there's a lot of time. You know, our 501 00:27:23,960 --> 00:27:27,920 Speaker 1: galaxy is almost as old as the universe, right, So 502 00:27:28,240 --> 00:27:31,320 Speaker 1: you're saying that we should take the time to mension 503 00:27:31,440 --> 00:27:34,359 Speaker 1: into account to not just how big space is, but 504 00:27:35,080 --> 00:27:37,880 Speaker 1: how old it is. Also makes it more what you're saying, 505 00:27:37,920 --> 00:27:40,800 Speaker 1: it makes it more likely that we'll get visited. Yeah, exactly, 506 00:27:40,840 --> 00:27:43,560 Speaker 1: because there's been a lot of time. So the galaxy 507 00:27:43,600 --> 00:27:45,880 Speaker 1: has been around for you know, more than ten billion 508 00:27:46,040 --> 00:27:48,920 Speaker 1: years um, though our planets only existed for you know, 509 00:27:49,000 --> 00:27:50,920 Speaker 1: four and a half billion. But even just take a 510 00:27:51,040 --> 00:27:53,480 Speaker 1: few billion years, like, that's a lot of time to 511 00:27:53,640 --> 00:27:56,159 Speaker 1: explore the galaxy. The galaxy is a hundred thousand light 512 00:27:56,280 --> 00:27:59,120 Speaker 1: years across, but it's been around for billions of years, 513 00:27:59,200 --> 00:28:01,240 Speaker 1: So even though you have the speed of light, it's 514 00:28:01,320 --> 00:28:04,760 Speaker 1: not actually that impossible to explore the entire galaxy. So 515 00:28:04,840 --> 00:28:07,200 Speaker 1: I thought, well, what if you have an alien ship 516 00:28:07,720 --> 00:28:09,320 Speaker 1: and you wanted to do that, and you wanted to 517 00:28:09,359 --> 00:28:12,600 Speaker 1: go from star to star and explore every single solar 518 00:28:12,680 --> 00:28:15,239 Speaker 1: system in the galaxy? How long would that take? How 519 00:28:15,280 --> 00:28:17,199 Speaker 1: long would it take for you to check off all 520 00:28:17,240 --> 00:28:19,359 Speaker 1: the boxes? Like if you're an alien and you have O, 521 00:28:19,480 --> 00:28:21,680 Speaker 1: C D, how long and you wanted to visit every 522 00:28:21,760 --> 00:28:24,520 Speaker 1: single star because you're you're like an intense tourist, how 523 00:28:24,560 --> 00:28:27,800 Speaker 1: long would it take? Care that's right, you have the 524 00:28:28,040 --> 00:28:34,200 Speaker 1: ultimate bucket lift, and yeah, how long would that take? 525 00:28:34,800 --> 00:28:36,720 Speaker 1: And and then I thought, well, let's not visit every 526 00:28:36,720 --> 00:28:39,880 Speaker 1: single star. Maybe these folks are out hunting four aliens, 527 00:28:40,240 --> 00:28:42,920 Speaker 1: so let's have them only visit stars that have Earth 528 00:28:43,000 --> 00:28:44,880 Speaker 1: like planets. So that cuts it down by a factor 529 00:28:44,920 --> 00:28:49,040 Speaker 1: of five. So now you have fifty billion stars in 530 00:28:49,160 --> 00:28:51,600 Speaker 1: the Milky Way to visit. That's the fraction we think 531 00:28:51,680 --> 00:28:54,640 Speaker 1: have Earth like Oh I see, they would only you 532 00:28:54,640 --> 00:28:58,600 Speaker 1: would only pick stars you think might have life on him. Yeah, exactly, 533 00:28:59,120 --> 00:29:02,160 Speaker 1: because we're interested being contacted by aliens that we can 534 00:29:02,200 --> 00:29:05,480 Speaker 1: talk to and learn physics from, and you know, share 535 00:29:06,160 --> 00:29:08,640 Speaker 1: the experience of being alive in this universe, and so 536 00:29:09,200 --> 00:29:11,680 Speaker 1: you could be totally wide open to lots of different 537 00:29:11,760 --> 00:29:13,920 Speaker 1: kinds of life. And I'm a huge fan of that. 538 00:29:14,040 --> 00:29:17,160 Speaker 1: I imagining like life in the core of stars whatever. 539 00:29:17,320 --> 00:29:19,040 Speaker 1: But you know, life that we can talk to and 540 00:29:19,080 --> 00:29:21,719 Speaker 1: interact with and have a chance to be technologically similar 541 00:29:21,760 --> 00:29:24,360 Speaker 1: to probably gonna come from earthlike planets. Okay, so how 542 00:29:24,440 --> 00:29:27,080 Speaker 1: long would it take us? Yeah, how long would it take? Well, Um, 543 00:29:27,200 --> 00:29:30,920 Speaker 1: the average distance between earthlike planets is about ten or 544 00:29:31,000 --> 00:29:34,560 Speaker 1: eleven light years, right, the average distance between stars is 545 00:29:34,600 --> 00:29:37,120 Speaker 1: about four ish light years, But there are not every 546 00:29:37,160 --> 00:29:39,320 Speaker 1: star as an earthlike planet, so it's about ten or 547 00:29:39,320 --> 00:29:43,160 Speaker 1: eleven light years between earthlike planets, and so again, assuming 548 00:29:43,200 --> 00:29:44,920 Speaker 1: you can travel at half the speed of light, it 549 00:29:45,000 --> 00:29:48,440 Speaker 1: takes you know, something like five years to go from 550 00:29:48,520 --> 00:29:52,000 Speaker 1: one to the other. Oh, I see, And that's assuming 551 00:29:52,160 --> 00:29:56,160 Speaker 1: that you sort of search efficiently, right, Like you have 552 00:29:56,240 --> 00:29:59,400 Speaker 1: a pretty good path to get them all. Yeah, exactly, 553 00:29:59,480 --> 00:30:02,120 Speaker 1: you start from one center and you sort of spiral outwards, 554 00:30:02,520 --> 00:30:06,120 Speaker 1: and you know, there's some additional geometrical complications there because 555 00:30:06,720 --> 00:30:08,960 Speaker 1: but but there are path to explore the galaxy where 556 00:30:08,960 --> 00:30:11,080 Speaker 1: you don't have to do a lot of backtracking, and 557 00:30:11,160 --> 00:30:13,160 Speaker 1: even if you do, that's not a huge factor, you know. 558 00:30:13,280 --> 00:30:15,480 Speaker 1: And again that's a factor to maybe and we're just 559 00:30:15,600 --> 00:30:18,680 Speaker 1: interested in sort of generally getting this answer right. And 560 00:30:18,880 --> 00:30:21,160 Speaker 1: so of course you're gonna get ended with a big number. Right. 561 00:30:21,200 --> 00:30:24,200 Speaker 1: You've got fifty billion solar systems with Earth like planets. 562 00:30:24,560 --> 00:30:28,440 Speaker 1: Each one takes twenty years to visit, and so you know, 563 00:30:28,520 --> 00:30:31,720 Speaker 1: you're talking trillions of years just in our galaxy, just 564 00:30:31,880 --> 00:30:34,880 Speaker 1: for our galaxy. And you know, you might imagine aliens 565 00:30:34,880 --> 00:30:39,280 Speaker 1: and other galaxies, but the distance between galaxies is ginormous 566 00:30:39,440 --> 00:30:41,920 Speaker 1: compared to the size of the galaxy, and so that's 567 00:30:42,120 --> 00:30:45,160 Speaker 1: you know, basically totally impractical without worms. That's why I's 568 00:30:45,160 --> 00:30:48,479 Speaker 1: focusing on just our galaxies. So a single ship would take, 569 00:30:48,560 --> 00:30:51,360 Speaker 1: you know, order trillions of years to explore the galaxy, 570 00:30:51,800 --> 00:30:55,200 Speaker 1: assuming you meaning like if you're in Captain Picard on 571 00:30:55,280 --> 00:31:00,400 Speaker 1: the starship Enterprise and you wanted to explore every possible 572 00:31:01,240 --> 00:31:03,520 Speaker 1: planet that might have life on this galaxy, it would 573 00:31:03,520 --> 00:31:05,880 Speaker 1: take you trillions of years. Yeah, exactly. It would take 574 00:31:05,880 --> 00:31:08,480 Speaker 1: you much longer than the age of the galaxy. So 575 00:31:08,680 --> 00:31:10,600 Speaker 1: even if you started when the galaxy was born, you 576 00:31:10,680 --> 00:31:12,720 Speaker 1: were like the first intelligent race in the galaxy, and 577 00:31:12,760 --> 00:31:15,560 Speaker 1: you started exploring in ten billion years, you wouldn't have 578 00:31:15,960 --> 00:31:18,440 Speaker 1: visited a significant fraction in the galaxy, you know, So 579 00:31:18,640 --> 00:31:21,120 Speaker 1: it could certainly be what that What that means is 580 00:31:21,280 --> 00:31:23,640 Speaker 1: it could be that there is an alien Picard out 581 00:31:23,680 --> 00:31:27,239 Speaker 1: there studiously visiting every solar system in the galaxy. Well, 582 00:31:27,280 --> 00:31:29,920 Speaker 1: Patrick Stewart isn't is an alien also, but let's not 583 00:31:29,960 --> 00:31:32,600 Speaker 1: get into that. He also seems to be about a 584 00:31:32,640 --> 00:31:36,800 Speaker 1: trillion years old. But he looks great. I want to 585 00:31:36,840 --> 00:31:39,200 Speaker 1: be that sexy when I'm tread. But you know, so 586 00:31:39,360 --> 00:31:41,520 Speaker 1: that means there could be an alien ship out there 587 00:31:41,520 --> 00:31:44,360 Speaker 1: exploring the galaxy, and it's reasonable that hasn't visited the 588 00:31:44,400 --> 00:31:47,360 Speaker 1: Earth yet. All right, that's interesting. But then you can 589 00:31:47,400 --> 00:31:49,160 Speaker 1: start to play the numbers game. You could say, well, 590 00:31:49,800 --> 00:31:51,760 Speaker 1: what if there are a thousand ships, what if there 591 00:31:51,800 --> 00:31:55,440 Speaker 1: are million ships? What if there are billion aliens out there? Right? 592 00:31:56,160 --> 00:31:58,920 Speaker 1: And you can do these calculations for for lots of 593 00:31:58,960 --> 00:32:02,280 Speaker 1: different ships. I see not that an alien would make 594 00:32:02,320 --> 00:32:05,240 Speaker 1: a billion ships, but let's say that each of the 595 00:32:05,400 --> 00:32:08,840 Speaker 1: billions of alien races out there made one ship to explore. 596 00:32:09,360 --> 00:32:12,120 Speaker 1: Surely one of them would have hit us by now 597 00:32:12,400 --> 00:32:14,880 Speaker 1: or found us. Yeah, exactly. So if there I did 598 00:32:14,920 --> 00:32:19,000 Speaker 1: the numbers, and if you have a billion exploring alien ships, 599 00:32:19,360 --> 00:32:21,080 Speaker 1: you know then it tis takes it takes about a 600 00:32:21,160 --> 00:32:26,040 Speaker 1: thousand years to explore the whole galaxy, right, yeah, because 601 00:32:26,120 --> 00:32:28,239 Speaker 1: you know there's lots of ships, and so what does 602 00:32:28,320 --> 00:32:30,760 Speaker 1: that tell you, Well, we've been around for a thousand years. 603 00:32:31,040 --> 00:32:33,360 Speaker 1: If aliens had come and made themselves known in the 604 00:32:33,600 --> 00:32:35,680 Speaker 1: last thousand years, we would certainly be aware of that 605 00:32:36,440 --> 00:32:38,680 Speaker 1: um And so what that tells you is there are 606 00:32:38,760 --> 00:32:42,720 Speaker 1: not a billion alien exploring ships. And again, you know, 607 00:32:42,800 --> 00:32:45,280 Speaker 1: these are aliens that are interested in visiting us and 608 00:32:45,280 --> 00:32:47,920 Speaker 1: would make themselves known when they arrive right. Put aside 609 00:32:47,960 --> 00:32:50,240 Speaker 1: the question of how they visited in the government is 610 00:32:50,280 --> 00:32:52,680 Speaker 1: covering it up, etcetera, etcetera. But what if they came 611 00:32:52,720 --> 00:32:55,080 Speaker 1: while we weren't ready? You know, like what if they 612 00:32:55,160 --> 00:32:57,720 Speaker 1: came knocked on the door we weren't ready or maybe 613 00:32:57,880 --> 00:33:00,120 Speaker 1: even existing because humans have only been around for like, 614 00:33:00,400 --> 00:33:03,680 Speaker 1: you know, a couple of ten tens of thousands of years. Right, Yeah, 615 00:33:03,720 --> 00:33:05,440 Speaker 1: that's a great question. That time to mension is a 616 00:33:05,480 --> 00:33:08,080 Speaker 1: great one. But here's the thing is that a billion 617 00:33:08,160 --> 00:33:11,880 Speaker 1: ships can explore the galaxy every thousand years. And so 618 00:33:12,280 --> 00:33:15,000 Speaker 1: if you're out there looking for aliens, you might like 619 00:33:15,680 --> 00:33:18,600 Speaker 1: check on a planet and look back right and say like, okay, well, 620 00:33:18,880 --> 00:33:21,320 Speaker 1: you know, I got this one billion of the galaxy 621 00:33:21,400 --> 00:33:23,800 Speaker 1: to sort of patrol. I'm gonna come back every thousand 622 00:33:23,920 --> 00:33:27,120 Speaker 1: years and say, you know, are there aliens yet? I mean, 623 00:33:27,200 --> 00:33:30,760 Speaker 1: are there is there intelligence yet? And so every thousand years, 624 00:33:30,800 --> 00:33:34,120 Speaker 1: a billion ships can visit every planet in the galaxy. 625 00:33:34,720 --> 00:33:37,600 Speaker 1: You're saying that maybe they could have come a thousands 626 00:33:37,680 --> 00:33:39,720 Speaker 1: or tens of thousands of years ago, but then said, 627 00:33:40,160 --> 00:33:44,080 Speaker 1: you know, their trash is not quite ripe yet, Let's 628 00:33:44,160 --> 00:33:49,520 Speaker 1: come back when they're totally abusing their environment, throwing out 629 00:33:49,600 --> 00:33:52,560 Speaker 1: prime trash. Yeah, exactly, and the time tomension has a 630 00:33:52,640 --> 00:33:55,320 Speaker 1: lot of complications. You know, did they come when we 631 00:33:55,360 --> 00:33:57,840 Speaker 1: couldn't recognize them? Are they about to come? This sort 632 00:33:57,880 --> 00:34:00,520 Speaker 1: of stuff. But a billion ships have come, you know, 633 00:34:00,600 --> 00:34:03,000 Speaker 1: every thousand years or so, and then you can crank 634 00:34:03,040 --> 00:34:04,880 Speaker 1: the numbers down and say, okay, well there's definitely not 635 00:34:05,040 --> 00:34:07,560 Speaker 1: a billion ships, because then we'd be visited every thousand 636 00:34:07,640 --> 00:34:10,160 Speaker 1: years and we certainly would have noticed that. You know, 637 00:34:10,280 --> 00:34:12,000 Speaker 1: but if there were a million ships. But if there 638 00:34:12,040 --> 00:34:15,360 Speaker 1: were a million ships exploring the galaxy, and so I 639 00:34:15,440 --> 00:34:18,200 Speaker 1: have the numbers here, that would take you know, about 640 00:34:18,239 --> 00:34:21,160 Speaker 1: a million years. So a million ships will take about 641 00:34:21,160 --> 00:34:24,000 Speaker 1: a million years to explore the whole galaxy. And so 642 00:34:24,120 --> 00:34:26,359 Speaker 1: then you can wonder, like, well, if aliens came here 643 00:34:26,400 --> 00:34:29,560 Speaker 1: a million years ago, would they have stuck around where 644 00:34:29,600 --> 00:34:33,160 Speaker 1: they have like left us a note saying, hey, when 645 00:34:33,200 --> 00:34:36,120 Speaker 1: you get it together and figure out technology, here's how 646 00:34:36,160 --> 00:34:38,800 Speaker 1: to contact us, or here's what to do or something. 647 00:34:39,160 --> 00:34:40,719 Speaker 1: Or maybe they just figure oh, we'll come back in 648 00:34:40,800 --> 00:34:43,360 Speaker 1: another million and see what's going on. Or maybe they 649 00:34:43,440 --> 00:34:48,840 Speaker 1: did stick around and they are on that's right, we 650 00:34:48,960 --> 00:34:51,440 Speaker 1: are the aliens and so this gets harder. But you 651 00:34:51,520 --> 00:34:54,160 Speaker 1: can also do the same trick where you invert it. 652 00:34:54,200 --> 00:34:56,719 Speaker 1: You can say, well, look, i'm pretty sure there are 653 00:34:56,800 --> 00:35:01,000 Speaker 1: not a billion alien ships exploring the galaxy. Right. We 654 00:35:01,080 --> 00:35:03,480 Speaker 1: can't really say there aren't a million, though, Right There 655 00:35:03,520 --> 00:35:07,000 Speaker 1: could be a million alien ships exploring the galaxy and 656 00:35:07,080 --> 00:35:09,759 Speaker 1: they would only get to Earth every million years or so. 657 00:35:10,480 --> 00:35:12,880 Speaker 1: And so it certainly could be that there are million 658 00:35:12,960 --> 00:35:16,560 Speaker 1: aliens out there exploring the galaxy looking for us, but 659 00:35:16,680 --> 00:35:18,799 Speaker 1: they came by a million years ago we weren't ready, right, 660 00:35:18,960 --> 00:35:22,280 Speaker 1: And again you're assuming that you're ruling out a class 661 00:35:22,280 --> 00:35:25,759 Speaker 1: of anies that would be interested in us or making 662 00:35:25,840 --> 00:35:28,360 Speaker 1: themselves known, right, Like what if they're just looking for 663 00:35:29,840 --> 00:35:32,200 Speaker 1: you know, raccoon gold poop and they don't see it 664 00:35:32,280 --> 00:35:35,400 Speaker 1: here until they keep going. Yeah, exactly, ruling out aliens 665 00:35:35,480 --> 00:35:38,320 Speaker 1: that that don't make themselves known or stay hidden or 666 00:35:38,400 --> 00:35:41,280 Speaker 1: just come by and steal the you know, heavy metals 667 00:35:41,320 --> 00:35:45,560 Speaker 1: they're particularly interested in and move on. Okay, all right, 668 00:35:45,600 --> 00:35:48,760 Speaker 1: So that that helps narrow it down a little bit, Yeah, exactly, 669 00:35:48,800 --> 00:35:51,040 Speaker 1: that helps narrow down. It's like exploring the kind of 670 00:35:51,080 --> 00:35:53,719 Speaker 1: ways they could see us, and does physics limit us? 671 00:35:54,000 --> 00:35:56,000 Speaker 1: And it turns out that you know, physics doesn't really 672 00:35:56,040 --> 00:36:00,239 Speaker 1: limit us because while the galaxy is large, there is 673 00:36:00,480 --> 00:36:02,640 Speaker 1: there's been a lot of time to do this exploration. 674 00:36:02,920 --> 00:36:05,480 Speaker 1: So if you have enough ships, you certainly can visit 675 00:36:06,000 --> 00:36:09,000 Speaker 1: every solar system in the galaxy and not a significant 676 00:36:09,040 --> 00:36:11,440 Speaker 1: fraction of the age of the galaxy, which is billions 677 00:36:11,480 --> 00:36:14,080 Speaker 1: of years. Well, there is a way you were telling 678 00:36:14,120 --> 00:36:17,759 Speaker 1: me that shoots that number up super high and makes 679 00:36:17,800 --> 00:36:20,480 Speaker 1: it super likely that we would have been contacted by 680 00:36:20,520 --> 00:36:23,359 Speaker 1: aliens um, which is a pretty interesting idea. And then 681 00:36:23,400 --> 00:36:25,640 Speaker 1: we can get into have they been here at all? 682 00:36:26,360 --> 00:36:41,600 Speaker 1: But first let's take another quick break. Okay, so I 683 00:36:41,640 --> 00:36:43,799 Speaker 1: think we can sort of rule out that there are 684 00:36:43,880 --> 00:36:46,759 Speaker 1: billions of aliens out there that have heard is and 685 00:36:46,800 --> 00:36:49,280 Speaker 1: one of visitors or that even are out there exploring 686 00:36:49,560 --> 00:36:53,560 Speaker 1: and want to say hi to us. UM. Just from 687 00:36:53,600 --> 00:36:57,359 Speaker 1: the fact that we haven't been contacted by them, sort 688 00:36:57,400 --> 00:36:59,480 Speaker 1: of rules out that there are a whole lot of 689 00:36:59,520 --> 00:37:01,279 Speaker 1: them out there ready to do that. But you're saying, 690 00:37:01,280 --> 00:37:03,640 Speaker 1: there's another way that we could explore or they could 691 00:37:03,640 --> 00:37:05,960 Speaker 1: explore the galaxy that we should have seen by Now, 692 00:37:06,200 --> 00:37:08,600 Speaker 1: that's right, and the idea is you want a lot 693 00:37:08,640 --> 00:37:11,440 Speaker 1: of ships because you there are a lot of stars 694 00:37:12,120 --> 00:37:14,680 Speaker 1: and it's sort of awkward to build all those ships. 695 00:37:14,960 --> 00:37:16,960 Speaker 1: Like here on Earth, say, we wanted to do this 696 00:37:17,280 --> 00:37:20,720 Speaker 1: this exploration, We wanted to take this task on building 697 00:37:20,719 --> 00:37:23,040 Speaker 1: a billion ships from Earth. Sounds kind of hard, build 698 00:37:23,080 --> 00:37:26,840 Speaker 1: them one at a time. So there's a famous idea 699 00:37:27,120 --> 00:37:30,480 Speaker 1: by von Neumann. So Neuman probes and he said, well 700 00:37:30,520 --> 00:37:32,960 Speaker 1: what if we build a few ships and those ships 701 00:37:33,200 --> 00:37:36,960 Speaker 1: build more ships. So essentially you send out a ship 702 00:37:37,280 --> 00:37:40,800 Speaker 1: which then finds a planet, uses the raw materials on 703 00:37:40,880 --> 00:37:44,400 Speaker 1: that planet to assemble a ship building factory. Right, So 704 00:37:44,560 --> 00:37:48,120 Speaker 1: now one ship builds a factory that makes more ships. Right. 705 00:37:48,520 --> 00:37:51,239 Speaker 1: It's sort of the way like rats fill up a city. 706 00:37:51,640 --> 00:37:55,000 Speaker 1: You don't have one mama rat have a billion babies, right, 707 00:37:55,280 --> 00:37:57,880 Speaker 1: she has ten babies, and those ten babies have ten babies, 708 00:37:57,880 --> 00:37:59,719 Speaker 1: and those ten babies have ten babies, and pretty soon 709 00:37:59,719 --> 00:38:02,520 Speaker 1: you've got a billion rats, right kind of Or like viruses, right, 710 00:38:02,960 --> 00:38:05,520 Speaker 1: Like they invade a cell and they use the cell 711 00:38:05,600 --> 00:38:08,880 Speaker 1: to replicate exactly just like a virus. So we should 712 00:38:08,920 --> 00:38:11,960 Speaker 1: be the virus, rats and viruses. This is not not 713 00:38:12,239 --> 00:38:18,040 Speaker 1: favorable not favorable analogies here. Yeah, well, um and that's 714 00:38:18,040 --> 00:38:21,000 Speaker 1: the idea. And you know that might seem like, what 715 00:38:21,280 --> 00:38:23,759 Speaker 1: is that crazy? It's it's a little crazy, but it's 716 00:38:24,040 --> 00:38:27,600 Speaker 1: it's sort of weirdly not that far off technologically. I mean, 717 00:38:27,680 --> 00:38:31,240 Speaker 1: we have factories now that are mostly stocked with robots. 718 00:38:31,360 --> 00:38:34,800 Speaker 1: Robots can build cars, so can robots build themselves. I 719 00:38:34,840 --> 00:38:37,840 Speaker 1: don't think that's too far off. The tricky thing is, 720 00:38:37,880 --> 00:38:42,040 Speaker 1: you know, landing on a planet, finding those resources, mining them. 721 00:38:42,400 --> 00:38:44,080 Speaker 1: But you don't even need to land on planets like 722 00:38:44,160 --> 00:38:48,160 Speaker 1: asteroids we know are filled with valuable materials, iron and 723 00:38:48,560 --> 00:38:50,719 Speaker 1: all sorts of heavy metals that you might need to 724 00:38:51,080 --> 00:38:54,360 Speaker 1: build these things. So imagine that we can do that, 725 00:38:54,480 --> 00:38:56,800 Speaker 1: and you know, I would estimate where maybe a hundred 726 00:38:56,920 --> 00:38:58,759 Speaker 1: two hundred years away from being able to do that. 727 00:38:59,280 --> 00:39:03,000 Speaker 1: You launch just one of those things, it launches five more, 728 00:39:03,320 --> 00:39:06,759 Speaker 1: They launch five more very quickly. You get up to 729 00:39:06,920 --> 00:39:10,320 Speaker 1: millions and millions of ships exploring the galaxy. You do 730 00:39:10,440 --> 00:39:13,600 Speaker 1: the calculation, it doesn't take very long to explore the 731 00:39:13,800 --> 00:39:17,320 Speaker 1: entire galaxy. So so you have like a satellite orbiting 732 00:39:17,440 --> 00:39:20,799 Speaker 1: every single earth like planet in the entire galaxy within 733 00:39:20,920 --> 00:39:24,839 Speaker 1: tens of thousands of years. You can go viral. Yeah, 734 00:39:25,000 --> 00:39:29,239 Speaker 1: that's exactly we go viral. So that's fascinating, right. Um, 735 00:39:29,520 --> 00:39:33,280 Speaker 1: Now there's another question like, are these crude probes or uncrude? 736 00:39:33,280 --> 00:39:35,319 Speaker 1: I don't want to say man, because you know there 737 00:39:35,360 --> 00:39:37,439 Speaker 1: are men or women on them. You know, I don't 738 00:39:37,480 --> 00:39:39,439 Speaker 1: know that we want to send people on these things 739 00:39:39,560 --> 00:39:41,560 Speaker 1: and then have those people have kids and then put 740 00:39:41,600 --> 00:39:45,839 Speaker 1: those babies on the ships to explore. Just make more 741 00:39:45,880 --> 00:39:49,560 Speaker 1: ships and more people. Yeah, exactly, I don't know that 742 00:39:49,600 --> 00:39:51,680 Speaker 1: we want people to go viral. So imagine we're just 743 00:39:51,760 --> 00:39:54,680 Speaker 1: sending probes. Right, then those probes could send a message 744 00:39:54,800 --> 00:39:59,120 Speaker 1: back to Earth if they do find something. But again, 745 00:39:59,280 --> 00:40:01,720 Speaker 1: you can flip it around. You can say, well, shouldn't 746 00:40:01,719 --> 00:40:05,000 Speaker 1: aliens have thought of this idea? Um? Aliens? You know, 747 00:40:05,040 --> 00:40:07,480 Speaker 1: if we're pretty close technologically to being able to do this, 748 00:40:07,960 --> 00:40:10,839 Speaker 1: Aliens probably would be. Also, given the billions of years 749 00:40:10,920 --> 00:40:14,680 Speaker 1: that the galaxy has been around and yet no self 750 00:40:14,800 --> 00:40:18,399 Speaker 1: replicating probes have landed on Earth, and so that's kind 751 00:40:18,400 --> 00:40:22,680 Speaker 1: of disappointing. If you can have this viral exploration scenario, 752 00:40:23,600 --> 00:40:26,240 Speaker 1: then you might have even more than a million probes 753 00:40:26,239 --> 00:40:30,200 Speaker 1: out there. You could have billions of probes out there eventually. Yeah, 754 00:40:32,960 --> 00:40:35,240 Speaker 1: it grows pretty quickly. Yeah, you can go from millions 755 00:40:35,280 --> 00:40:39,080 Speaker 1: to billions pretty quickly. And so you would expect somebody 756 00:40:39,120 --> 00:40:41,960 Speaker 1: else to have this idea and frankly for the galaxy 757 00:40:42,040 --> 00:40:44,440 Speaker 1: to be filled with these things, and yet it's not. 758 00:40:45,080 --> 00:40:48,000 Speaker 1: And yet it's not, which means what we can put 759 00:40:48,080 --> 00:40:50,800 Speaker 1: a pretty hard limit. That means like, there are no 760 00:40:51,040 --> 00:40:54,320 Speaker 1: alien species in our galaxy that have had this idea 761 00:40:54,440 --> 00:40:56,600 Speaker 1: and done it, not even one. It would take only 762 00:40:56,719 --> 00:41:01,359 Speaker 1: one to fill the galaxy and completely explore it. Uh well, 763 00:41:01,400 --> 00:41:04,040 Speaker 1: it seems like a pretty crazy idea, isn't it. Why 764 00:41:04,080 --> 00:41:06,560 Speaker 1: would you even do that just just to reach out 765 00:41:06,880 --> 00:41:09,719 Speaker 1: out there into the universe, I guess yeah, because we 766 00:41:09,840 --> 00:41:11,960 Speaker 1: want to know, right, Like I want to know if 767 00:41:12,040 --> 00:41:14,880 Speaker 1: any earth like planet in the galaxy has life. So 768 00:41:15,160 --> 00:41:16,840 Speaker 1: I mean, if we have the technology to do this, 769 00:41:17,120 --> 00:41:19,040 Speaker 1: oh my god, I would send that pro about tomorrow. 770 00:41:19,760 --> 00:41:23,960 Speaker 1: Absolutely interesting, wouldn't you. Yeah? Well it would cost a 771 00:41:24,000 --> 00:41:25,919 Speaker 1: lot of money, wouldn't it. The R and D would 772 00:41:25,920 --> 00:41:27,960 Speaker 1: cost a lot, you know, to figure out how to 773 00:41:28,040 --> 00:41:30,000 Speaker 1: get a ship, to build a copy of itself, to 774 00:41:30,040 --> 00:41:32,920 Speaker 1: build a ship making factory. But once you send it 775 00:41:32,960 --> 00:41:35,320 Speaker 1: out then it doesn't use any more resources, right It 776 00:41:35,520 --> 00:41:38,160 Speaker 1: builds more of itself based on what it finds out there. 777 00:41:38,440 --> 00:41:41,120 Speaker 1: It's like viral marketing, right, It's pretty cheap to launch 778 00:41:41,320 --> 00:41:44,480 Speaker 1: and pretty effective, right right. So, but you're saying the 779 00:41:44,600 --> 00:41:48,719 Speaker 1: fact that we haven't seen these sort of rules out 780 00:41:48,800 --> 00:41:52,400 Speaker 1: that there are aliens who would have this idea and 781 00:41:52,560 --> 00:41:56,920 Speaker 1: the resources and the smarts. Yeah, exactly. The fact that 782 00:41:57,160 --> 00:41:59,279 Speaker 1: that we haven't seen them, that it has doesn't seem 783 00:41:59,320 --> 00:42:02,759 Speaker 1: to have happened, means that there's nobody else out there 784 00:42:03,120 --> 00:42:05,640 Speaker 1: who had this idea and did it right and and 785 00:42:05,719 --> 00:42:08,560 Speaker 1: would make themselves known. Maybe maybe they have come to 786 00:42:08,640 --> 00:42:12,280 Speaker 1: our solar system, but they just reported back and moved on. Perhaps, 787 00:42:12,719 --> 00:42:14,920 Speaker 1: But you know, if they came to our solar system 788 00:42:15,000 --> 00:42:17,960 Speaker 1: before they moved on, they would need to build more ships, right, 789 00:42:18,040 --> 00:42:20,520 Speaker 1: and so they'd have to like build a ship making 790 00:42:20,600 --> 00:42:23,279 Speaker 1: factory somewhere. And if if they landed on Earth and 791 00:42:23,640 --> 00:42:25,680 Speaker 1: mind the Earth to make a ship making factory, I 792 00:42:25,760 --> 00:42:28,480 Speaker 1: think we would see signs of that. Or I mean 793 00:42:28,520 --> 00:42:30,600 Speaker 1: it could be there out somewhere in the asteroid belt 794 00:42:30,960 --> 00:42:33,920 Speaker 1: and they like mind an asteroid and then left. But 795 00:42:34,120 --> 00:42:36,400 Speaker 1: you know, if the idea is you could leave a 796 00:42:36,560 --> 00:42:39,600 Speaker 1: probe in every solar system sort of sitting there orbiting 797 00:42:39,640 --> 00:42:43,080 Speaker 1: earthlike planets, waiting for intelligence to crop up, and so 798 00:42:43,360 --> 00:42:45,160 Speaker 1: it should still be here and we certainly would have 799 00:42:45,200 --> 00:42:46,960 Speaker 1: found it if there was a probe orbiting the Earth 800 00:42:47,040 --> 00:42:51,800 Speaker 1: from that was not terrestrial. Well, that's such an interesting exercise, 801 00:42:51,880 --> 00:42:54,160 Speaker 1: you know, to think about how it's possible to get 802 00:42:54,200 --> 00:42:56,759 Speaker 1: contacted by aliens and then flip it around and say, well, 803 00:42:56,800 --> 00:42:58,399 Speaker 1: if we have, that's the fact that we haven't been 804 00:42:58,440 --> 00:43:02,040 Speaker 1: contacted means that we can rule these possibilities. Yeah, And frankly, 805 00:43:02,120 --> 00:43:04,520 Speaker 1: that's the thing that dampens my enthusiasm the most. Like 806 00:43:04,640 --> 00:43:07,680 Speaker 1: I'm a big believer that there could be aliens out 807 00:43:07,719 --> 00:43:11,120 Speaker 1: there that are technological and worth talking to. But the 808 00:43:11,200 --> 00:43:13,480 Speaker 1: fact that none of them have sent have had this 809 00:43:13,640 --> 00:43:17,160 Speaker 1: idea and sent probes the physics Earth, that makes me doubt. 810 00:43:17,360 --> 00:43:19,920 Speaker 1: That makes me wonder, like maybe we are alone in 811 00:43:19,960 --> 00:43:23,040 Speaker 1: the galaxy, because surely somebody else would have had this idea. 812 00:43:23,120 --> 00:43:26,160 Speaker 1: That's not such a brilliant idea that only humans would 813 00:43:26,160 --> 00:43:29,520 Speaker 1: have come up with it. So frankly that that that 814 00:43:29,600 --> 00:43:31,360 Speaker 1: bums me out a little bit. You're saying you believe 815 00:43:31,400 --> 00:43:35,400 Speaker 1: physics more than you believe Joe rogan I believe the 816 00:43:35,440 --> 00:43:37,799 Speaker 1: physics more than I believe Bob Lazar, that's for sure. 817 00:43:39,440 --> 00:43:41,440 Speaker 1: All right. Well, I think that's sort of the conclusion 818 00:43:41,600 --> 00:43:44,879 Speaker 1: we set out to explore, is that basically, you're saying, 819 00:43:44,920 --> 00:43:48,120 Speaker 1: physics says that it is not impossible for us to 820 00:43:48,200 --> 00:43:52,480 Speaker 1: get contacted by other intelligent species, right, You're saying that 821 00:43:52,880 --> 00:43:55,200 Speaker 1: that's right, It's totally possible, and there are many ways 822 00:43:55,239 --> 00:43:57,200 Speaker 1: that they could do it. And there are many ways 823 00:43:57,200 --> 00:44:00,080 Speaker 1: they could have heard us and come visitors, or are 824 00:44:00,120 --> 00:44:02,560 Speaker 1: many ways that they could be out there exploring the star, 825 00:44:03,160 --> 00:44:06,080 Speaker 1: you know, checking out their bucket list and oh c 826 00:44:06,320 --> 00:44:11,080 Speaker 1: d um compulsions to to visit every star. And and 827 00:44:11,239 --> 00:44:14,440 Speaker 1: the fact that we haven't um maybe tells you a 828 00:44:14,480 --> 00:44:18,000 Speaker 1: little bit about how alone we are in the galaxy exactly. 829 00:44:18,120 --> 00:44:20,640 Speaker 1: And so I think buried in the in the physics message, 830 00:44:20,680 --> 00:44:23,520 Speaker 1: there is the reason for hope, right, it's possible to 831 00:44:23,600 --> 00:44:26,399 Speaker 1: go across the stars and define aliens. And then there's 832 00:44:26,400 --> 00:44:29,520 Speaker 1: also a reason for a disappointment. Um, physics isn't the 833 00:44:29,640 --> 00:44:33,000 Speaker 1: reason why we haven't been contacted, and so you have 834 00:44:33,120 --> 00:44:36,160 Speaker 1: to think about other reasons why maybe the aliens are 835 00:44:36,200 --> 00:44:39,000 Speaker 1: just so alien they heard our message. But didn't didn't 836 00:44:39,080 --> 00:44:42,319 Speaker 1: understand it, or maybe they came here and saw us 837 00:44:42,440 --> 00:44:45,880 Speaker 1: and weren't interested. You know. So there are lots of ways. 838 00:44:46,120 --> 00:44:48,120 Speaker 1: There are lots of ways this could happen. But blame 839 00:44:48,160 --> 00:44:53,680 Speaker 1: your breath. Don't blame physics. That's right. It's probably your fault. 840 00:44:55,400 --> 00:45:00,759 Speaker 1: It's not physics, it is you, that's right. That's right. 841 00:45:01,120 --> 00:45:03,359 Speaker 1: But this is a really fun kind of calculation. Think 842 00:45:03,360 --> 00:45:06,200 Speaker 1: about what's possible to do back of the envelope calculations. 843 00:45:06,239 --> 00:45:08,920 Speaker 1: None of the calculations we did here today are precise. 844 00:45:09,000 --> 00:45:11,000 Speaker 1: They're all approximate. They could be wrong by a factor 845 00:45:11,160 --> 00:45:13,520 Speaker 1: ten um. But you know, it gives us an idea. 846 00:45:14,000 --> 00:45:15,560 Speaker 1: And and that's the kind of thing that I that 847 00:45:15,640 --> 00:45:17,440 Speaker 1: I stay up late wondering about. When I'm camping and 848 00:45:17,480 --> 00:45:19,680 Speaker 1: I'm looking up in the stars and I'm wondering who 849 00:45:19,800 --> 00:45:22,640 Speaker 1: else is out there? Um, and my physics brain gets 850 00:45:22,680 --> 00:45:25,000 Speaker 1: engaged and tries to give me a reason for why 851 00:45:25,200 --> 00:45:28,200 Speaker 1: they haven't yet contacted us and made themselves know them. Well, 852 00:45:28,239 --> 00:45:30,120 Speaker 1: I stay up late wondering how do I stop these 853 00:45:30,160 --> 00:45:34,759 Speaker 1: recruits from going through my trash? And and why would you? 854 00:45:34,880 --> 00:45:40,280 Speaker 1: Because your trash is their chocolate? All right? Well, Hopefully 855 00:45:40,440 --> 00:45:42,960 Speaker 1: that gives you some solids that maybe we are alone 856 00:45:43,000 --> 00:45:45,520 Speaker 1: in the universe. But hey, Daniel, at least you still 857 00:45:45,600 --> 00:45:49,080 Speaker 1: have physics, that's right, and chocolate and gold pood possibly. 858 00:45:50,920 --> 00:45:53,279 Speaker 1: All right, Thanks for tuning in everyone, see you next time. 859 00:46:00,719 --> 00:46:03,000 Speaker 1: If you still have a question after listening to all 860 00:46:03,080 --> 00:46:06,239 Speaker 1: these explanations, please drop us a line. We'd love to 861 00:46:06,360 --> 00:46:08,720 Speaker 1: hear from you. You can find us at Facebook, Twitter, 862 00:46:08,840 --> 00:46:12,480 Speaker 1: and Instagram at Daniel and Jorge That's one Word, or 863 00:46:12,640 --> 00:46:16,000 Speaker 1: email us at Feedback at Daniel and Jorge dot com. 864 00:46:16,560 --> 00:46:19,360 Speaker 1: Thanks for listening, and remember that Daniel and Jorge Explain 865 00:46:19,440 --> 00:46:22,440 Speaker 1: the Universe is a production of I Heart Radio from 866 00:46:22,480 --> 00:46:25,399 Speaker 1: More podcast from my heart Radio visit the I heart 867 00:46:25,480 --> 00:46:29,040 Speaker 1: Radio app, Apple Podcasts, or wherever you listen to your 868 00:46:29,120 --> 00:46:29,840 Speaker 1: favorite shows.