1 00:00:00,160 --> 00:00:02,360 Speaker 1: Hey, please take a second and leave us a review 2 00:00:02,440 --> 00:00:06,240 Speaker 1: on Apple Podcasts, Spotify, or wherever you listen to the podcast. 3 00:00:06,920 --> 00:00:07,440 Speaker 2: Thanks a lot. 4 00:00:08,520 --> 00:00:12,080 Speaker 1: Hey, Welcome to Science Stuff, a production of iHeartRadio. I'm 5 00:00:12,119 --> 00:00:17,239 Speaker 1: Horehea Champ and today we are looking for aliens. There 6 00:00:17,239 --> 00:00:20,680 Speaker 1: are trillions upon trillions of stars out there with planets 7 00:00:20,720 --> 00:00:23,280 Speaker 1: that are not too different from the one we're living on, 8 00:00:23,880 --> 00:00:27,120 Speaker 1: which means it's very likely that there's other life out 9 00:00:27,160 --> 00:00:31,040 Speaker 1: there in the universe, and that begs the question where 10 00:00:31,080 --> 00:00:34,440 Speaker 1: are they? Why haven't we seen them, heard from them, 11 00:00:34,600 --> 00:00:37,479 Speaker 1: or why haven't they come here. We're going to talk 12 00:00:37,520 --> 00:00:40,280 Speaker 1: to three scientists who've worked on the search for alien 13 00:00:40,320 --> 00:00:42,920 Speaker 1: life and we're going to hear whether they think it's 14 00:00:43,080 --> 00:00:46,280 Speaker 1: likely we'll ever find it. So get ready to leave 15 00:00:46,320 --> 00:00:49,000 Speaker 1: Earth as we cast our eyes and ears to the 16 00:00:49,040 --> 00:00:52,640 Speaker 1: cosmos to answer the question where are all the aliens? 17 00:00:58,920 --> 00:00:59,120 Speaker 3: Hey? 18 00:00:59,120 --> 00:01:01,760 Speaker 1: Everyone, all right, I'm just gonna come out and say it. 19 00:01:02,080 --> 00:01:06,160 Speaker 1: I think there are aliens out there. Now, before you 20 00:01:06,200 --> 00:01:10,160 Speaker 1: think I'm some crazy conspiracy theorists, hear me out. There 21 00:01:10,200 --> 00:01:14,000 Speaker 1: are one hundred billion stars in our galaxy and at 22 00:01:14,080 --> 00:01:18,679 Speaker 1: least that many galaxies in the observable universe. Scientists estimate 23 00:01:18,720 --> 00:01:22,000 Speaker 1: that about one in ten stars has a planet that's 24 00:01:22,160 --> 00:01:26,479 Speaker 1: like Earth, rocky and toasty enough to support life as 25 00:01:26,480 --> 00:01:29,559 Speaker 1: we know it. This means there are at least one 26 00:01:29,880 --> 00:01:34,199 Speaker 1: six tillion or one, followed by twenty one zeros Earth 27 00:01:34,319 --> 00:01:38,480 Speaker 1: like planets out there. Plus the universe is fourteen billion 28 00:01:38,560 --> 00:01:41,720 Speaker 1: years old, which is a long time for lots of 29 00:01:41,760 --> 00:01:45,320 Speaker 1: things to have happened. Now, if you look at life 30 00:01:45,319 --> 00:01:48,680 Speaker 1: around this here on Earth, it does seem pretty special. 31 00:01:49,280 --> 00:01:52,600 Speaker 1: But is it one in one sixty million. That's one 32 00:01:52,680 --> 00:01:56,760 Speaker 1: followed by twenty one zeros times fourteen billion years special. 33 00:01:57,320 --> 00:02:00,960 Speaker 1: I'm willing to bet that it's not, But of course 34 00:02:01,200 --> 00:02:05,200 Speaker 1: we don't know yet. That is the topic of today's episode. 35 00:02:05,600 --> 00:02:08,360 Speaker 1: Why don't we know? And what are we doing to 36 00:02:08,480 --> 00:02:11,480 Speaker 1: find out? Now? The search for life outside of our 37 00:02:11,520 --> 00:02:15,800 Speaker 1: planet can be basically split into two. One is the 38 00:02:15,840 --> 00:02:19,679 Speaker 1: search for basic life, meaning are there bacteria like life 39 00:02:19,720 --> 00:02:23,320 Speaker 1: forms and the moons of Jupiter or simple organisms in 40 00:02:23,360 --> 00:02:27,480 Speaker 1: the atmosphere of distant planets? And two is the search 41 00:02:27,680 --> 00:02:32,000 Speaker 1: for intelligent life. Are there little green beings in flying 42 00:02:32,040 --> 00:02:37,360 Speaker 1: saucers or vast civilizations with advanced technology? So in today's 43 00:02:37,400 --> 00:02:40,880 Speaker 1: episode we'll tackle these one at a time. First we'll 44 00:02:40,880 --> 00:02:43,720 Speaker 1: talk about the search for basic life, and then we'll 45 00:02:43,720 --> 00:02:46,959 Speaker 1: cover the search for intelligent life, and then at the 46 00:02:47,080 --> 00:02:50,919 Speaker 1: end we'll talk to an anthropologist who specializes in how 47 00:02:51,000 --> 00:02:55,680 Speaker 1: people would react if we ever did find extraterrestrial life. 48 00:02:56,080 --> 00:02:59,440 Speaker 1: Would we phone home, live long and prosper or fight 49 00:02:59,639 --> 00:03:03,239 Speaker 1: and not go quietly into the night? And bonus points 50 00:03:03,280 --> 00:03:06,480 Speaker 1: if you get all three of those movie references. All right, 51 00:03:06,600 --> 00:03:10,000 Speaker 1: let's start with the search for basic life. To guide 52 00:03:10,080 --> 00:03:16,359 Speaker 1: us through this, here's my chat with Professor Chris Impi. Well, 53 00:03:16,360 --> 00:03:17,919 Speaker 1: thank you, doctor imp for joining us. 54 00:03:18,040 --> 00:03:19,680 Speaker 2: Yes, it's good to be with you. My name is 55 00:03:19,720 --> 00:03:22,680 Speaker 2: Chris Impi. I'm a professor of astronomy at the University 56 00:03:22,720 --> 00:03:23,440 Speaker 2: of Arizona. 57 00:03:23,560 --> 00:03:25,760 Speaker 1: I thought maybe you could start by telling us what 58 00:03:25,840 --> 00:03:29,040 Speaker 1: are some of the different ways that us humans are 59 00:03:29,200 --> 00:03:31,640 Speaker 1: trying to find life outside of our planet. 60 00:03:31,800 --> 00:03:34,680 Speaker 2: Sure, well, you let off with where are all the aliens? 61 00:03:34,840 --> 00:03:37,720 Speaker 2: So we can maybe move back to that. But that's 62 00:03:37,760 --> 00:03:41,000 Speaker 2: her reprise is a question that Enrico Fermi asked well 63 00:03:41,000 --> 00:03:43,400 Speaker 2: way back in nineteen fifty, where he was saying where 64 00:03:43,440 --> 00:03:45,920 Speaker 2: are they? Where are all the aliens? So I think, 65 00:03:45,960 --> 00:03:48,520 Speaker 2: in practical terms, mostly we're going to be talking about 66 00:03:48,560 --> 00:03:51,920 Speaker 2: looking for microbial life or basic forms of life. So 67 00:03:51,960 --> 00:03:55,040 Speaker 2: there are a set of strategies and they're coming to 68 00:03:55,080 --> 00:03:57,800 Speaker 2: fruition now because we didn't know who were Earth like 69 00:03:57,880 --> 00:04:01,320 Speaker 2: planets or habitable planets elsewhere, and now we know all 70 00:04:01,400 --> 00:04:04,560 Speaker 2: of that, so it's like game on for finding life. 71 00:04:05,440 --> 00:04:08,040 Speaker 1: Okay. The first thing doctor Impy wanted to caution us 72 00:04:08,080 --> 00:04:11,240 Speaker 1: on the search for basic or simple life forms is 73 00:04:11,280 --> 00:04:14,760 Speaker 1: that life is neither basic nor simple. 74 00:04:15,400 --> 00:04:17,520 Speaker 2: If you want a biologist to wrap you on the knuckles, 75 00:04:17,560 --> 00:04:22,159 Speaker 2: just say microbes are temple. So there are the people 76 00:04:22,200 --> 00:04:24,360 Speaker 2: who try and create life in the lab, you know, 77 00:04:24,480 --> 00:04:27,599 Speaker 2: start to generate life from simple chemical ingredients and see 78 00:04:27,600 --> 00:04:29,599 Speaker 2: if they can simulate what they think happened on the 79 00:04:29,640 --> 00:04:32,840 Speaker 2: Earth four billion years ago. They haven't succeeded yet. It's 80 00:04:32,880 --> 00:04:36,320 Speaker 2: a very difficult lab experiment. They point to some very 81 00:04:36,320 --> 00:04:39,560 Speaker 2: difficult steps that have to be followed to go from 82 00:04:39,600 --> 00:04:43,040 Speaker 2: these very simple molecules of ten or twenty atoms to 83 00:04:43,200 --> 00:04:46,760 Speaker 2: the first replicating molecule to the first simple cell. And 84 00:04:46,839 --> 00:04:47,880 Speaker 2: cells are not simple. 85 00:04:48,920 --> 00:04:52,440 Speaker 1: Doctor imp explains. There are two general places where we 86 00:04:52,560 --> 00:04:56,200 Speaker 1: are looking for signs of basic life in our own 87 00:04:56,240 --> 00:05:00,080 Speaker 1: backyard here in our Solar System and also outside our 88 00:05:00,120 --> 00:05:04,600 Speaker 1: Solar system and planets around other stars. Now in our 89 00:05:04,640 --> 00:05:08,520 Speaker 1: Solar system, there aren't that many places besides Earth that 90 00:05:08,600 --> 00:05:12,280 Speaker 1: we can imagine there being life, at least life as 91 00:05:12,320 --> 00:05:16,000 Speaker 1: we think is possible. Mercury and Venus are too hot, 92 00:05:16,560 --> 00:05:20,479 Speaker 1: and all the planets Saturn and beyond are cold gas planets. 93 00:05:20,920 --> 00:05:24,000 Speaker 1: So the main place we've been looking is Mars. 94 00:05:25,560 --> 00:05:27,960 Speaker 2: So the first place to look for life is on 95 00:05:28,040 --> 00:05:30,880 Speaker 2: an in near's location that you can study in detail, 96 00:05:30,920 --> 00:05:34,640 Speaker 2: you know, place we've actually sent robotic probes Mars, and 97 00:05:34,720 --> 00:05:38,080 Speaker 2: so Mars is still at the epicenter of very active 98 00:05:38,240 --> 00:05:42,680 Speaker 2: searches for biology. So the first Mars life experiments with 99 00:05:42,760 --> 00:05:45,720 Speaker 2: the Twin Viking experiments in nineteen seventies. 100 00:05:45,880 --> 00:05:48,400 Speaker 1: So they sent some not robots but sort of like 101 00:05:48,520 --> 00:05:50,159 Speaker 1: little base stations to Mars. 102 00:05:50,240 --> 00:05:53,920 Speaker 2: Right, Yeah, and there are remarkable missions based on nineteen 103 00:05:53,960 --> 00:05:56,160 Speaker 2: sixties technology. There are far ahead of their time because 104 00:05:56,160 --> 00:05:59,120 Speaker 2: they actually did do life detection at two different locations 105 00:05:59,120 --> 00:06:02,040 Speaker 2: on the surface. It's remarkable stuff. Yeah, think of how 106 00:06:02,080 --> 00:06:05,160 Speaker 2: primitive computing was in the mid nineteen seventies. So there 107 00:06:05,160 --> 00:06:07,640 Speaker 2: were landers, so they were stationary, but they had little 108 00:06:07,880 --> 00:06:12,000 Speaker 2: diggers and so they scooted soil into containers and they 109 00:06:12,000 --> 00:06:14,480 Speaker 2: could add water to see if something happened, to see 110 00:06:14,480 --> 00:06:17,200 Speaker 2: if they could grow something or culture something, and they 111 00:06:17,200 --> 00:06:19,320 Speaker 2: did mostly return negative results. 112 00:06:20,480 --> 00:06:23,000 Speaker 1: So we've been looking for life on Mars since the 113 00:06:23,120 --> 00:06:30,159 Speaker 1: nineteen seventies. Then we started sending rovers. 114 00:06:28,480 --> 00:06:31,440 Speaker 2: And to sum up the research from the rovers of 115 00:06:31,520 --> 00:06:35,080 Speaker 2: the last thirty years, they were essentially looking for potential. 116 00:06:35,279 --> 00:06:37,719 Speaker 2: They were looking for organic material, They were looking for 117 00:06:37,960 --> 00:06:41,839 Speaker 2: possible evidence of life in the geochemistry of rocks without 118 00:06:41,920 --> 00:06:45,360 Speaker 2: actually looking for biology itself. So that was the limitation 119 00:06:45,520 --> 00:06:46,800 Speaker 2: and still is the limitation. 120 00:06:48,000 --> 00:06:50,760 Speaker 1: Over the last fifty years, we've been looking for the 121 00:06:50,800 --> 00:06:54,480 Speaker 1: science of life on Mars because scientists are pretty sure 122 00:06:54,880 --> 00:06:58,960 Speaker 1: Mars was once a lot like Earth. There were oceans 123 00:06:59,080 --> 00:07:02,480 Speaker 1: and rivers and in the atmosphere, but then it all 124 00:07:02,600 --> 00:07:07,000 Speaker 1: dried up and went away. Although that doesn't mean there 125 00:07:07,080 --> 00:07:10,120 Speaker 1: isn't still liquid water on Mars. 126 00:07:10,840 --> 00:07:15,240 Speaker 2: There's really good indirect evidence for subsurface liquid water aquifers. 127 00:07:15,640 --> 00:07:18,160 Speaker 2: It comes from a variety of sources, from radar, from 128 00:07:18,240 --> 00:07:21,400 Speaker 2: various things, people who've even seen little eruptions of sulf 129 00:07:21,440 --> 00:07:25,160 Speaker 2: surface water rolling down gullies. So you can absolutely have 130 00:07:25,280 --> 00:07:28,440 Speaker 2: liquid water under the surface, maybe ten fifty one hundred 131 00:07:28,520 --> 00:07:32,200 Speaker 2: meters kilometer down. But that opens the prospect that there 132 00:07:32,240 --> 00:07:35,600 Speaker 2: is life on Mars right now, not just fossilized life. 133 00:07:35,400 --> 00:07:39,000 Speaker 1: Or who knows, maybe a little Martian fish possibly. 134 00:07:38,720 --> 00:07:41,280 Speaker 2: Maybe slightly bigger than microbes. Yeah, if I mean, if 135 00:07:41,280 --> 00:07:45,120 Speaker 2: there are subsurface pockets of ocean or sea, they could 136 00:07:45,120 --> 00:07:47,480 Speaker 2: set up an ecosystem that might be more interesting than 137 00:07:47,520 --> 00:07:48,200 Speaker 2: just microbes. 138 00:07:48,280 --> 00:07:52,560 Speaker 1: Yeah, possibly in seeing people speculate, all right. The other 139 00:07:52,600 --> 00:07:55,560 Speaker 1: places we can look for life in our Solar system 140 00:07:55,720 --> 00:07:58,840 Speaker 1: are the moons of Jupiter and Saturn. 141 00:08:00,080 --> 00:08:03,160 Speaker 2: Ask how many places could there be the ingredients for life, 142 00:08:03,200 --> 00:08:06,840 Speaker 2: critically including liquid water in the Solar System. The answer 143 00:08:06,880 --> 00:08:09,920 Speaker 2: is probably a dozen a dozen, and all the rest 144 00:08:10,080 --> 00:08:14,000 Speaker 2: are giant planets moons, which are substantial worlds in their 145 00:08:14,040 --> 00:08:16,720 Speaker 2: own right. The biggest moons of the giant planets are 146 00:08:16,720 --> 00:08:19,880 Speaker 2: bigger than the Moon itself and almost like mercury size. 147 00:08:20,080 --> 00:08:23,480 Speaker 2: They can keep liquid water under a rocky crust. 148 00:08:24,240 --> 00:08:26,960 Speaker 1: What doctor MP's saying here is that in several of 149 00:08:27,040 --> 00:08:31,480 Speaker 1: the moons of Jupiter and Saturn, like Europa and Enceladus, 150 00:08:31,880 --> 00:08:36,360 Speaker 1: scientists believe there are huge underwater oceans that could have 151 00:08:36,559 --> 00:08:38,679 Speaker 1: life in them. 152 00:08:38,960 --> 00:08:42,320 Speaker 2: So Europa is a water world. It's entirely encased in 153 00:08:42,440 --> 00:08:46,280 Speaker 2: ice of probably five to ten kilometers thickness, and that 154 00:08:46,440 --> 00:08:49,160 Speaker 2: overlays an ocean that could be fifty to one hundred 155 00:08:49,200 --> 00:08:52,679 Speaker 2: kilometers deep. It's really substantial ocean, far more water than 156 00:08:52,720 --> 00:08:54,920 Speaker 2: the Earth's oceans. So people think of Earth as the 157 00:08:54,920 --> 00:08:57,920 Speaker 2: water world. That's not true. There's a couple of places 158 00:08:57,920 --> 00:09:00,000 Speaker 2: in the Solar System with more water than the Earth. 159 00:09:00,600 --> 00:09:03,319 Speaker 2: We're sending the Europea clipper there right now. That was 160 00:09:03,360 --> 00:09:06,760 Speaker 2: a successful launch just last year. It's going to make 161 00:09:06,920 --> 00:09:10,600 Speaker 2: very clever orbital measurements to look for traces of life 162 00:09:10,600 --> 00:09:13,440 Speaker 2: with spectroscopy and so on. It may even splash off 163 00:09:13,520 --> 00:09:17,280 Speaker 2: some icy material by sending a projectile under the surface 164 00:09:17,320 --> 00:09:19,839 Speaker 2: and then sniff the particles that come out. 165 00:09:20,120 --> 00:09:20,440 Speaker 1: Wow. 166 00:09:20,600 --> 00:09:22,920 Speaker 2: So it's not a true life detection experiment, but it's 167 00:09:22,960 --> 00:09:24,960 Speaker 2: going to learn a lot more about Europa than we 168 00:09:25,000 --> 00:09:28,440 Speaker 2: ever knew before. We also have Enceladus, which is a 169 00:09:28,480 --> 00:09:32,200 Speaker 2: tiny moon of Saturn where the icy geysers were found 170 00:09:32,320 --> 00:09:35,520 Speaker 2: ten or fifteen years ago, and those icy jets going 171 00:09:35,559 --> 00:09:38,760 Speaker 2: into space also indicate there was liquid water and sell 172 00:09:38,840 --> 00:09:41,200 Speaker 2: this it's irregular, it's a potato shaped, it's not even 173 00:09:41,240 --> 00:09:44,560 Speaker 2: a round object could have the ingredients for life. And 174 00:09:44,600 --> 00:09:48,320 Speaker 2: then the third most compelling place is Titan, so that's 175 00:09:48,360 --> 00:09:52,600 Speaker 2: the biggest moon of Saturn. Titan is fascinating because it's 176 00:09:52,600 --> 00:09:55,760 Speaker 2: a big moon. It has an atmosphere as thick as 177 00:09:55,760 --> 00:09:58,360 Speaker 2: the Earth's, and it's made of the same stuff nitrogen, 178 00:09:58,559 --> 00:10:02,840 Speaker 2: no oxygen, but nitrogen. It has weather, It has bodies 179 00:10:02,840 --> 00:10:08,080 Speaker 2: of liquid and lakes and river deltas and clouds and precipitation. 180 00:10:08,360 --> 00:10:11,839 Speaker 2: It has volcanism, but it's an alien world because it's 181 00:10:11,920 --> 00:10:15,000 Speaker 2: very cold, and so that liquid is not water. It's 182 00:10:15,080 --> 00:10:18,240 Speaker 2: ethane and methane. So the lakes on Titan are rather 183 00:10:18,360 --> 00:10:22,680 Speaker 2: strange organic brood that's not mostly water. And if you 184 00:10:22,720 --> 00:10:26,680 Speaker 2: ask a biologist, should you have biology in a medium 185 00:10:26,760 --> 00:10:30,920 Speaker 2: that's ethane and methane as opposed to water, they scratch 186 00:10:30,960 --> 00:10:34,600 Speaker 2: their heads and say, maybe you just get fanciful with 187 00:10:34,720 --> 00:10:38,599 Speaker 2: hypothetical biology. Yes, you could maybe form complex molecules in 188 00:10:38,679 --> 00:10:40,000 Speaker 2: that kind of a liquid medium. 189 00:10:41,480 --> 00:10:44,720 Speaker 1: So to summarize, there are lots of places right here 190 00:10:44,760 --> 00:10:48,199 Speaker 1: in our solar system where there could be alien life. 191 00:10:48,720 --> 00:10:51,640 Speaker 1: But the problem, according to doctor imp is there's no 192 00:10:51,760 --> 00:10:56,600 Speaker 1: funding to go look Sending probes or drones to landlin 193 00:10:56,679 --> 00:10:59,920 Speaker 1: titen or drill under the ice or ground in Europe 194 00:11:00,280 --> 00:11:04,120 Speaker 1: or Mars is expensive, and things at NASA are not 195 00:11:04,240 --> 00:11:07,240 Speaker 1: looking so good right now for science funding. 196 00:11:08,360 --> 00:11:10,640 Speaker 2: So the bottom line on the Solar System is, yes, 197 00:11:10,679 --> 00:11:12,800 Speaker 2: there could be life elsewhere in the Solar System, but 198 00:11:12,960 --> 00:11:16,160 Speaker 2: the experiments are very difficult, the timelines are long, they're 199 00:11:16,200 --> 00:11:20,120 Speaker 2: expensive experiments, and some most astronomers saying the first detection 200 00:11:20,160 --> 00:11:23,240 Speaker 2: of life on Earth will come by looking at excelp. 201 00:11:22,960 --> 00:11:27,720 Speaker 1: Planets, planets that are in other stars, not the Sun. 202 00:11:27,880 --> 00:11:31,640 Speaker 2: Right, planets orbiting other stars, of which we found thousands now, 203 00:11:31,840 --> 00:11:34,200 Speaker 2: including hundreds that are roughly Earth like. 204 00:11:34,520 --> 00:11:37,000 Speaker 1: Well, but if they're so far away, how can we 205 00:11:37,160 --> 00:11:38,640 Speaker 1: tell if they have life. 206 00:11:38,840 --> 00:11:42,280 Speaker 2: Well, the life detection experiment is just the cutting, the 207 00:11:42,440 --> 00:11:44,000 Speaker 2: very cutting, bleeding edge. 208 00:11:44,559 --> 00:11:46,559 Speaker 1: All right. When we come back, we'll talk about how 209 00:11:46,559 --> 00:11:49,960 Speaker 1: to look for alien life in distant planets. We'll talk 210 00:11:49,960 --> 00:11:55,360 Speaker 1: to another astronomer who specializes looking for intelligent alien life 211 00:11:55,800 --> 00:12:12,600 Speaker 1: out there. Don't go anywhere, we'll be right back, welcome back. 212 00:12:14,720 --> 00:12:18,000 Speaker 1: All right. We're talking about the search for alien life, 213 00:12:18,600 --> 00:12:21,160 Speaker 1: and we're going to get to the search for intelligent 214 00:12:21,360 --> 00:12:24,440 Speaker 1: alien life but first we're going to hear from Professor 215 00:12:24,520 --> 00:12:27,839 Speaker 1: Chris Impi about how we're looking for the signs of 216 00:12:27,960 --> 00:12:34,880 Speaker 1: basic life and planets far away outside of our Solar system. Okay, 217 00:12:35,400 --> 00:12:37,960 Speaker 1: you were saying that we can use James Webb and 218 00:12:38,000 --> 00:12:42,200 Speaker 1: some ground based telescopes to possibly detect life in other planets. 219 00:12:42,559 --> 00:12:45,400 Speaker 2: Right, We're not taking pictures and seeing things swimming around 220 00:12:45,440 --> 00:12:48,720 Speaker 2: in a in an exo ocean, or watching you know, 221 00:12:49,880 --> 00:12:53,600 Speaker 2: exo dinosaurs lumbering about on a continent on a planet 222 00:12:53,640 --> 00:12:56,040 Speaker 2: one hundred light years away. None of that wonderful thing. 223 00:12:56,160 --> 00:12:58,240 Speaker 2: It's going to happen. It would be great, but it's 224 00:12:58,280 --> 00:13:01,199 Speaker 2: some science fiction forever. So this is what you do. 225 00:13:01,360 --> 00:13:03,400 Speaker 2: The idea is it's sort of based on the Earth 226 00:13:03,800 --> 00:13:06,840 Speaker 2: because the air we breathe, one part in five is oxygen, 227 00:13:06,920 --> 00:13:09,800 Speaker 2: and that oxygen was put there by microbes mostly billions 228 00:13:09,800 --> 00:13:12,959 Speaker 2: of years ago, and that oxygen is the telltale as 229 00:13:13,080 --> 00:13:15,240 Speaker 2: for someone looking at the Earth from far away, that 230 00:13:15,280 --> 00:13:17,720 Speaker 2: the Earth is a living planet, even if they couldn't 231 00:13:17,720 --> 00:13:18,520 Speaker 2: see anything else. 232 00:13:19,320 --> 00:13:22,559 Speaker 1: What doctor MP is saying here is that planets outside 233 00:13:22,600 --> 00:13:25,680 Speaker 1: our Solar System are too far away for us to 234 00:13:25,800 --> 00:13:28,880 Speaker 1: really take a picture of them. The closest planet to 235 00:13:29,000 --> 00:13:32,560 Speaker 1: us out there is orbiting a star called Proxima Centauri, 236 00:13:32,920 --> 00:13:36,800 Speaker 1: four point twenty five light years or twenty five trillion 237 00:13:36,840 --> 00:13:40,440 Speaker 1: miles away. Not even our best telescopes can get a 238 00:13:40,520 --> 00:13:43,040 Speaker 1: clear enough view of them to tell if they have 239 00:13:43,200 --> 00:13:46,160 Speaker 1: life on them. So the main way we're looking for 240 00:13:46,320 --> 00:13:50,880 Speaker 1: basic life in other planets is by studying their atmosphere. 241 00:13:51,360 --> 00:13:54,160 Speaker 1: That we can do by looking at the light they reflect. 242 00:13:54,440 --> 00:13:57,080 Speaker 1: And once your sign of life is having a lot 243 00:13:57,120 --> 00:13:58,720 Speaker 1: of oxygen. 244 00:13:59,600 --> 00:14:03,079 Speaker 2: Imagine the biosphere the whole life on our shuts down overnight, 245 00:14:03,200 --> 00:14:05,959 Speaker 2: within a few million years, the oxygen will be gone. 246 00:14:06,360 --> 00:14:08,599 Speaker 2: It would bind with rock, it would rust things, it 247 00:14:08,600 --> 00:14:11,280 Speaker 2: would dissolve in the oceans, and it would disappear because 248 00:14:11,280 --> 00:14:15,200 Speaker 2: it's sustained by life. So the reverse logic is that 249 00:14:15,240 --> 00:14:18,200 Speaker 2: if you see oxygen in the planet, that's a good 250 00:14:18,320 --> 00:14:21,840 Speaker 2: sign that there's biology on that planet. So oxygen in 251 00:14:21,880 --> 00:14:26,440 Speaker 2: that way is what's called a biomarker or biosignature by astrobiologists. 252 00:14:26,520 --> 00:14:28,400 Speaker 2: So methane is a biomarker too. 253 00:14:29,520 --> 00:14:34,080 Speaker 1: The study of potential life in other planets is called astrobiology. 254 00:14:34,600 --> 00:14:37,400 Speaker 1: Now we have been able to see faint signs of 255 00:14:37,440 --> 00:14:40,480 Speaker 1: the atmosphere and far away planets. But it's such a 256 00:14:40,520 --> 00:14:43,200 Speaker 1: hard problem. We haven't been able to do it in 257 00:14:43,280 --> 00:14:45,280 Speaker 1: the right kind of planet. 258 00:14:46,480 --> 00:14:49,160 Speaker 2: They've proved that you can sniff the atmosphere of an 259 00:14:49,160 --> 00:14:52,520 Speaker 2: exoplanet and say what's in it, but they've been done 260 00:14:52,560 --> 00:14:56,560 Speaker 2: for more massive planets, more like neptunes and urinous type 261 00:14:56,560 --> 00:15:00,440 Speaker 2: planets gas giants, not growth like terrestrial planets. So it's 262 00:15:00,560 --> 00:15:03,640 Speaker 2: just just too hard. And then the question is how 263 00:15:03,640 --> 00:15:06,080 Speaker 2: can we do better? And then we have to wait 264 00:15:06,120 --> 00:15:09,840 Speaker 2: for this next generation of three large telescopes all under construction. 265 00:15:10,920 --> 00:15:13,280 Speaker 1: So that's where we are in the search for basic 266 00:15:13,360 --> 00:15:16,680 Speaker 1: life out there in our Solar system. We need to 267 00:15:16,760 --> 00:15:20,560 Speaker 1: fund better, more complicated missions to go out there and 268 00:15:20,640 --> 00:15:24,600 Speaker 1: bring back samples from Mars or the Moon's Europa or 269 00:15:24,720 --> 00:15:28,720 Speaker 1: Titan and beyond our Solar system. We need better telescopes 270 00:15:29,000 --> 00:15:31,120 Speaker 1: just to get a whiff of the science of life 271 00:15:31,320 --> 00:15:35,360 Speaker 1: in the atmosphere of distant planets. And that brings us 272 00:15:35,360 --> 00:15:38,840 Speaker 1: to the search for intelligent life out there, and for 273 00:15:38,920 --> 00:15:42,560 Speaker 1: that we might not need such fancy equipment because we 274 00:15:42,640 --> 00:15:45,000 Speaker 1: might not need to go looking for it. It might 275 00:15:45,440 --> 00:15:48,960 Speaker 1: come to us to guide us through this possibility. I 276 00:15:49,080 --> 00:15:51,480 Speaker 1: reached out to Professor Jason Wright. 277 00:15:53,200 --> 00:15:56,680 Speaker 3: I am Jason Right, a professor of astronomy and astrophysics 278 00:15:56,720 --> 00:15:59,680 Speaker 3: at Penn State, and I'm also the director of the 279 00:15:59,680 --> 00:16:04,040 Speaker 3: Penn State Extraterrestrial Intelligence Center, where we look at all 280 00:16:04,080 --> 00:16:07,360 Speaker 3: aspects of the search for intelligent life in the universe. 281 00:16:07,560 --> 00:16:11,040 Speaker 1: Amazing and just adult check. You're not an alien yourself? 282 00:16:11,080 --> 00:16:12,080 Speaker 1: Are you not? 283 00:16:12,240 --> 00:16:15,440 Speaker 3: As far as I know, Yes, yes, I'm not. 284 00:16:15,480 --> 00:16:16,760 Speaker 1: I mean, oh, that would be a good plot to 285 00:16:16,880 --> 00:16:20,280 Speaker 1: this if the director of the search for intelligence turned 286 00:16:20,280 --> 00:16:22,040 Speaker 1: out to be an alien but he didn't know didn't 287 00:16:22,080 --> 00:16:22,360 Speaker 1: know it? 288 00:16:22,440 --> 00:16:26,040 Speaker 3: Right, Yeah, all right. 289 00:16:26,160 --> 00:16:28,320 Speaker 1: The first thing that they're right. I wanted to clarify 290 00:16:28,400 --> 00:16:32,080 Speaker 1: for us is that looking for intelligence out there in 291 00:16:32,120 --> 00:16:35,280 Speaker 1: the universe is kind of the wrong way to go 292 00:16:35,320 --> 00:16:37,120 Speaker 1: about it. 293 00:16:37,680 --> 00:16:40,480 Speaker 3: So we use the word intelligence a little loosely. We 294 00:16:40,520 --> 00:16:42,880 Speaker 3: don't mean it in a literal sense of intelligence. What 295 00:16:42,960 --> 00:16:46,120 Speaker 3: we're looking for is technology because we imagine that it 296 00:16:46,200 --> 00:16:49,960 Speaker 3: might be much easier to find signs of technology across 297 00:16:50,000 --> 00:16:52,160 Speaker 3: the stars than signs of life. 298 00:16:52,520 --> 00:16:55,400 Speaker 1: Now, why do you draw this distinction between intelligence and technology? 299 00:16:55,440 --> 00:16:57,480 Speaker 1: Isn't it sort of the same? Like put in one 300 00:16:57,480 --> 00:16:58,200 Speaker 1: imply the other. 301 00:16:58,440 --> 00:17:01,000 Speaker 3: We try to be really careful with that word intelligence. 302 00:17:01,200 --> 00:17:03,640 Speaker 3: The word intelligence gets used in a lot of ways, like, 303 00:17:03,720 --> 00:17:07,440 Speaker 3: you know, if you're looking at a culture that never 304 00:17:07,560 --> 00:17:12,280 Speaker 3: developed radio transmitters, are they not intelligent? You know, we 305 00:17:12,320 --> 00:17:15,600 Speaker 3: don't want to equate certain kinds of technology with a 306 00:17:15,640 --> 00:17:18,280 Speaker 3: much broader and squisher concept of intelligencing. 307 00:17:19,240 --> 00:17:21,919 Speaker 1: What doctor Wright is saying is that what you're doing 308 00:17:22,040 --> 00:17:25,040 Speaker 1: when you say you're looking for aliens, is you're really 309 00:17:25,080 --> 00:17:29,480 Speaker 1: looking for signs of technology, because there could be perfectly 310 00:17:29,520 --> 00:17:32,720 Speaker 1: intelligent aliens out there, but we may never see them 311 00:17:32,920 --> 00:17:35,920 Speaker 1: if they don't use technology that tells us they're there. 312 00:17:36,440 --> 00:17:39,879 Speaker 1: For example, Earth had intelligent life on it for thousands 313 00:17:39,920 --> 00:17:43,679 Speaker 1: of years before we even invented the light bulb. Or 314 00:17:43,800 --> 00:17:48,120 Speaker 1: think about whales or dolphins. They're intelligent, but an alien 315 00:17:48,160 --> 00:17:51,760 Speaker 1: species far away looking at Earth might never know they're 316 00:17:51,920 --> 00:17:52,520 Speaker 1: even here. 317 00:17:53,560 --> 00:17:56,240 Speaker 3: In fact, there have been many proposed alternative names for 318 00:17:56,280 --> 00:17:58,520 Speaker 3: this field. Freeman Dyson said it should be called the 319 00:17:58,520 --> 00:18:02,960 Speaker 3: Search for Extraterrestrial Technology, which would be set tea and 320 00:18:03,240 --> 00:18:06,359 Speaker 3: Jill Tarter, who looks for radio waves, said, you know, 321 00:18:06,359 --> 00:18:09,080 Speaker 3: I'm not going to detect any intelligence except that that 322 00:18:09,200 --> 00:18:12,520 Speaker 3: went into building a radio transmitter, which is electrical engineering. 323 00:18:12,600 --> 00:18:16,680 Speaker 3: So she joked it was a search for extraterrestrial electrical engineers, 324 00:18:17,119 --> 00:18:20,280 Speaker 3: which is also set easy fit. Yeah, so as long 325 00:18:20,320 --> 00:18:22,760 Speaker 3: as you just say SETI, you're you're good. 326 00:18:23,840 --> 00:18:26,520 Speaker 1: Okay, this is kind of a semantic argument. What you 327 00:18:26,600 --> 00:18:30,160 Speaker 1: really want to know is where are the smart aliens? Well, 328 00:18:30,240 --> 00:18:32,400 Speaker 1: the way that their right breaks it down is that 329 00:18:32,480 --> 00:18:35,440 Speaker 1: there are really only three ways in which we'll ever 330 00:18:35,760 --> 00:18:40,560 Speaker 1: have confirmation of intelligent life out there. We're not traveling 331 00:18:40,560 --> 00:18:43,760 Speaker 1: to other stars anytime soon, so the only ways left 332 00:18:44,000 --> 00:18:47,600 Speaker 1: are a if we see signs of their technology from here, 333 00:18:48,160 --> 00:18:51,800 Speaker 1: b if they come visit us and see if they're 334 00:18:51,800 --> 00:18:54,560 Speaker 1: trying to talk to us, or if we happen to 335 00:18:54,640 --> 00:19:00,000 Speaker 1: catch them talking to other aliens. Now, let's be clear, 336 00:19:00,359 --> 00:19:03,680 Speaker 1: none of these things have happened. We haven't noticed any 337 00:19:03,720 --> 00:19:07,560 Speaker 1: alien civilizations out there. We haven't been visited by aliens 338 00:19:07,800 --> 00:19:10,560 Speaker 1: as far as I know, despite what you might have heard, 339 00:19:10,840 --> 00:19:13,840 Speaker 1: and we haven't received a call from an alien yet. 340 00:19:14,359 --> 00:19:14,879 Speaker 3: Why is that? 341 00:19:16,320 --> 00:19:19,800 Speaker 1: As I mentioned before, there are trillions of stars and 342 00:19:20,040 --> 00:19:23,280 Speaker 1: plenty of time in the universe. If there are aliens 343 00:19:23,320 --> 00:19:26,520 Speaker 1: out there, surely one of these things would have happened 344 00:19:26,600 --> 00:19:30,880 Speaker 1: by now. And this is what's known as the Fermi paradox. 345 00:19:31,800 --> 00:19:34,480 Speaker 1: So there's this idea called the Fermi paradox, and it 346 00:19:34,520 --> 00:19:38,360 Speaker 1: goes like this. Enrico Fermi was a famous physicist, and 347 00:19:38,560 --> 00:19:41,359 Speaker 1: in nineteen fifty, before we even started looking, they were 348 00:19:41,400 --> 00:19:44,760 Speaker 1: talking about UFOs and he realized the galaxy is so 349 00:19:45,000 --> 00:19:49,320 Speaker 1: old that even with just normal rockets, it would only 350 00:19:50,119 --> 00:19:53,480 Speaker 1: take millions of years to get every anywhere you wanted 351 00:19:53,520 --> 00:19:55,440 Speaker 1: to go in the galaxy. And since the galaxy is 352 00:19:55,480 --> 00:19:58,719 Speaker 1: billions of years old, there's plenty of time for them 353 00:19:58,760 --> 00:20:01,480 Speaker 1: to have gotten here by now, even without warp drive. 354 00:20:03,119 --> 00:20:07,280 Speaker 1: So where is everybody? Sometimes this gets phrased as we 355 00:20:07,359 --> 00:20:09,919 Speaker 1: expect them to be out there, why haven't we found 356 00:20:09,960 --> 00:20:14,240 Speaker 1: them yet? That's the Fermi paradox. And I should say 357 00:20:14,359 --> 00:20:17,199 Speaker 1: there have been whole papers written on why it's not 358 00:20:17,520 --> 00:20:21,200 Speaker 1: really a paradox, because we haven't yet real doubt that 359 00:20:21,240 --> 00:20:24,119 Speaker 1: there are no aliens. But the point is it's a 360 00:20:24,119 --> 00:20:27,639 Speaker 1: big question that is puzzling. Where are all the aliens? 361 00:20:27,960 --> 00:20:30,760 Speaker 1: And here doctor Wright thinks he has an answer. 362 00:20:31,760 --> 00:20:36,160 Speaker 3: The whole Fermi paradox thing is badly misunderstood because it's 363 00:20:36,200 --> 00:20:38,520 Speaker 3: not really a puzzle, Like, none of us doing this 364 00:20:38,600 --> 00:20:39,800 Speaker 3: work are worried about it. 365 00:20:40,960 --> 00:20:44,720 Speaker 1: Meaning you have an explanation for why we haven't themed 366 00:20:44,960 --> 00:20:50,200 Speaker 1: or found or been visited by any aides. Yeah, okay, 367 00:20:50,280 --> 00:20:53,160 Speaker 1: we're going to tackle each scenario in well we Aliens 368 00:20:53,359 --> 00:20:57,720 Speaker 1: one by one, starting with why haven't any aliens come 369 00:20:58,000 --> 00:21:02,120 Speaker 1: visit us? Well, let's say, and I'm asking you, why 370 00:21:02,160 --> 00:21:04,280 Speaker 1: haven't we've been visited by any aliens? 371 00:21:04,480 --> 00:21:07,280 Speaker 3: I would say there's a lot of reasons. So my 372 00:21:07,480 --> 00:21:12,160 Speaker 3: favorite is that we're here we haven't been visited by 373 00:21:12,240 --> 00:21:15,919 Speaker 3: other species, perhaps exactly because Earth has life, and so 374 00:21:16,160 --> 00:21:18,120 Speaker 3: maybe they've come through the Solar system and they've seen 375 00:21:18,160 --> 00:21:20,080 Speaker 3: the Earth has life, and maybe they've you know, gone, oh, 376 00:21:20,080 --> 00:21:21,639 Speaker 3: that's kind of interesting. But they're just going to leave 377 00:21:21,680 --> 00:21:25,320 Speaker 3: us alone and not land and invade and like try 378 00:21:25,359 --> 00:21:28,320 Speaker 3: and take the place over because it's got life. That's 379 00:21:28,359 --> 00:21:29,240 Speaker 3: my favorite answer. 380 00:21:30,080 --> 00:21:33,800 Speaker 1: So one possibility for why aliens haven't visited us is 381 00:21:34,520 --> 00:21:37,919 Speaker 1: maybe they have they just chose to leave us alone. 382 00:21:38,280 --> 00:21:40,239 Speaker 1: It's sort of like if you're on a hike and 383 00:21:40,280 --> 00:21:42,560 Speaker 1: you see an ant hill or you see a bear, 384 00:21:42,880 --> 00:21:45,639 Speaker 1: you don't run up to the ants or the bear screaming, 385 00:21:45,920 --> 00:21:48,120 Speaker 1: planting a flag where they live and try to teach 386 00:21:48,160 --> 00:21:51,920 Speaker 1: them about people, you just let them be. So maybe 387 00:21:52,000 --> 00:21:55,119 Speaker 1: aliens have been here, but they just moved on. 388 00:21:57,200 --> 00:22:00,240 Speaker 3: Another answer is spaceflight is just really hard. It's very, very, 389 00:22:00,359 --> 00:22:02,919 Speaker 3: very hard to build a machine that can last the 390 00:22:03,000 --> 00:22:05,800 Speaker 3: hundreds of thousands of years or millions of years it 391 00:22:05,840 --> 00:22:08,199 Speaker 3: would take to go to another star, and it's just 392 00:22:08,200 --> 00:22:11,160 Speaker 3: not worth it that no species ever does it more 393 00:22:11,200 --> 00:22:13,919 Speaker 3: than a couple of times tops, And so they haven't 394 00:22:14,080 --> 00:22:18,440 Speaker 3: visited every single star in the galaxy because interstellar flight 395 00:22:18,560 --> 00:22:20,720 Speaker 3: is just too hard and requires machines that would have 396 00:22:20,720 --> 00:22:21,520 Speaker 3: to last too long. 397 00:22:22,680 --> 00:22:25,760 Speaker 1: Another reason we haven't been visited by aliens is that 398 00:22:25,840 --> 00:22:29,919 Speaker 1: maybe space travel is too hard. Maybe warp drives are 399 00:22:30,080 --> 00:22:32,800 Speaker 1: just to fantasy, and the reality is that it takes 400 00:22:32,960 --> 00:22:37,160 Speaker 1: hundreds or thousands of years to go visit other star systems, 401 00:22:37,480 --> 00:22:41,240 Speaker 1: not to mention it's super expensive, so maybe going around 402 00:22:41,240 --> 00:22:45,320 Speaker 1: other planets is not really worth it, or maybe even 403 00:22:45,359 --> 00:22:49,280 Speaker 1: technologically possible. I mean, can you imagine making a machine 404 00:22:49,520 --> 00:22:53,640 Speaker 1: that would still work after one thousand years? All Right, 405 00:22:53,680 --> 00:22:55,600 Speaker 1: when we come back, we're going to hear the other 406 00:22:55,720 --> 00:22:59,199 Speaker 1: possibilities for why we haven't seen any aliens, and then 407 00:22:59,200 --> 00:23:02,400 Speaker 1: we're going to talk about what we're doing to find them, 408 00:23:03,000 --> 00:23:16,560 Speaker 1: stay with us. We'll be right back, and we're back 409 00:23:17,160 --> 00:23:20,480 Speaker 1: all right. We're asking the question where are all the aliens? 410 00:23:20,520 --> 00:23:23,719 Speaker 1: And so far we've talked about looking for basic life 411 00:23:23,800 --> 00:23:26,240 Speaker 1: in the universe, and now we're talking about the search 412 00:23:26,359 --> 00:23:29,960 Speaker 1: for intelligent life. There are trillions of planets out there 413 00:23:30,040 --> 00:23:33,800 Speaker 1: that could have intelligent life, So where is it They 414 00:23:33,800 --> 00:23:37,360 Speaker 1: could have visited us? But according to astronomer and director 415 00:23:37,440 --> 00:23:41,680 Speaker 1: of the Penn State Extraterrestrial Intelligence Center, Professor Jason Wright, 416 00:23:42,000 --> 00:23:44,840 Speaker 1: maybe they just chose to leave us alone, or maybe 417 00:23:44,880 --> 00:23:47,880 Speaker 1: we're just not worth coming all this way to meet us. 418 00:23:49,480 --> 00:23:52,040 Speaker 3: Maybe it's a little romantic to imagine that they'll all 419 00:23:52,119 --> 00:23:55,200 Speaker 3: leave us alone. Maybe a little two science fiction star 420 00:23:55,320 --> 00:23:58,840 Speaker 3: trek prime directivity, But I don't know, seems reasonable to me. 421 00:23:59,080 --> 00:24:01,560 Speaker 3: For whatever reason, they don't travel around a lot, or 422 00:24:01,600 --> 00:24:02,800 Speaker 3: if they come here, they don't. 423 00:24:02,640 --> 00:24:06,640 Speaker 1: Stay all right. Venix scenario for finding intelligent life out 424 00:24:06,640 --> 00:24:10,679 Speaker 1: there is seeing evidence of their advanced technology from here. 425 00:24:11,119 --> 00:24:14,440 Speaker 1: You could imagine seeing lights at night on an alien planet, 426 00:24:14,640 --> 00:24:18,119 Speaker 1: or hearing their TV or radio chatter, or maybe seeing 427 00:24:18,240 --> 00:24:21,919 Speaker 1: giant structures they build in space, like a ring world 428 00:24:22,240 --> 00:24:25,199 Speaker 1: or a space elevator. But doctor Wright says, there's a 429 00:24:25,240 --> 00:24:28,560 Speaker 1: simple explanation for why we haven't seen anything like that 430 00:24:28,880 --> 00:24:29,320 Speaker 1: so far. 431 00:24:30,359 --> 00:24:33,439 Speaker 3: We haven't seen evidence because it's very hard to find 432 00:24:33,680 --> 00:24:38,240 Speaker 3: anything out there at interstellar distances. I mean, we only 433 00:24:38,280 --> 00:24:42,440 Speaker 3: discovered giant planets the size of Earth thirty years ago, 434 00:24:42,560 --> 00:24:46,720 Speaker 3: and at great difficulty. NASA to find more has to 435 00:24:46,720 --> 00:24:49,520 Speaker 3: spend like a billion dollars on these big space observatories 436 00:24:49,520 --> 00:24:51,439 Speaker 3: to find these things. They're very hard to find. To 437 00:24:51,520 --> 00:24:54,480 Speaker 3: find the technology that just lives right on the surface 438 00:24:54,520 --> 00:24:58,040 Speaker 3: of these planets, it's really really hard, and there's no 439 00:24:58,119 --> 00:25:00,359 Speaker 3: reason to think we would have seen anything yet haven't 440 00:25:00,359 --> 00:25:00,880 Speaker 3: looked enough. 441 00:25:01,680 --> 00:25:04,320 Speaker 1: So the reason we haven't seen any obvious signs of 442 00:25:04,359 --> 00:25:08,480 Speaker 1: alien technology out there is that, again, space is too big. 443 00:25:08,880 --> 00:25:11,840 Speaker 1: The biggest image we have of other planets out there 444 00:25:11,880 --> 00:25:15,159 Speaker 1: are barely a few pixels, and that's because they're so 445 00:25:15,400 --> 00:25:18,560 Speaker 1: far away, and also because planets are right next to 446 00:25:18,680 --> 00:25:21,280 Speaker 1: bright stars, so it's like trying to make out the 447 00:25:21,359 --> 00:25:24,359 Speaker 1: picture on a coin that's right next to a lighthouse 448 00:25:24,520 --> 00:25:28,280 Speaker 1: three thousand miles away. But according to doctor Wright, there 449 00:25:28,320 --> 00:25:31,960 Speaker 1: are less obvious signs of alien technology we might be 450 00:25:31,960 --> 00:25:33,359 Speaker 1: able to see from here. 451 00:25:34,720 --> 00:25:34,880 Speaker 2: Now. 452 00:25:34,880 --> 00:25:36,840 Speaker 3: There are other things that they could do. People have 453 00:25:36,920 --> 00:25:39,320 Speaker 3: pointed out that, you know, we're trying to find planets 454 00:25:39,320 --> 00:25:41,359 Speaker 3: and see if they might have water on their surfaces. 455 00:25:41,400 --> 00:25:43,000 Speaker 3: But you know what if instead of seeing a lot 456 00:25:43,040 --> 00:25:45,720 Speaker 3: of chlorophyll on the surface, we see a lot of silicon. 457 00:25:46,680 --> 00:25:49,760 Speaker 3: Maybe it's covered in solar panels, right, Or maybe we're 458 00:25:49,800 --> 00:25:53,600 Speaker 3: studying the atmosphere and we discover chlorofloral carbons. We do 459 00:25:53,680 --> 00:25:56,479 Speaker 3: have chlorofloral carbons that are detectable in our atmosphere. So 460 00:25:56,520 --> 00:25:59,760 Speaker 3: those are two techno signatures here on Earth that might 461 00:25:59,800 --> 00:26:00,960 Speaker 3: be remotely detectable. 462 00:26:01,760 --> 00:26:04,800 Speaker 1: So we might not be able to see alien cities 463 00:26:05,040 --> 00:26:08,200 Speaker 1: because planets are too far away, but in those one 464 00:26:08,280 --> 00:26:11,199 Speaker 1: or two pixel images we can get, there could be 465 00:26:11,240 --> 00:26:14,560 Speaker 1: the signs of solar panels if their planet is covered 466 00:26:14,560 --> 00:26:17,359 Speaker 1: in them, or there could be signs of their industrial 467 00:26:17,400 --> 00:26:20,520 Speaker 1: pollution that we could tell from the light spectrum of 468 00:26:20,600 --> 00:26:23,160 Speaker 1: that one or two pixels of light we do get, 469 00:26:23,680 --> 00:26:26,720 Speaker 1: and our telescopes are getting better, so stay tuned for 470 00:26:26,960 --> 00:26:30,239 Speaker 1: maybe finding those signals in the future. Now you might 471 00:26:30,280 --> 00:26:33,200 Speaker 1: be wondering, or hey, haven't we been listening for alien 472 00:26:33,280 --> 00:26:36,200 Speaker 1: radio signals for a while now? Isn't that what SETI 473 00:26:36,400 --> 00:26:40,320 Speaker 1: the search for extra terrestrial intelligence is all about, well, 474 00:26:40,359 --> 00:26:43,040 Speaker 1: here's the thing. There's kind of no way that we 475 00:26:43,040 --> 00:26:45,960 Speaker 1: can point the radio antenna at a distant planet and 476 00:26:46,040 --> 00:26:49,879 Speaker 1: potentially listen to their TV broadcasts or their radio chatter. 477 00:26:50,320 --> 00:26:54,119 Speaker 1: Space is again too big, and any random signal like 478 00:26:54,160 --> 00:26:56,960 Speaker 1: that gets spread out and gets too weak by the 479 00:26:57,000 --> 00:26:59,760 Speaker 1: time it gets to us. Really, the only way we 480 00:26:59,760 --> 00:27:03,560 Speaker 1: can here alien signals is if they're actually trying to 481 00:27:03,720 --> 00:27:06,119 Speaker 1: talk to us, or at least trying to talk to 482 00:27:06,160 --> 00:27:10,240 Speaker 1: someone right behind us. In that case, the scenario is 483 00:27:10,240 --> 00:27:13,760 Speaker 1: that aliens know we're here, or they think we might 484 00:27:13,760 --> 00:27:17,199 Speaker 1: be here, and they're pointing their antennas at us and 485 00:27:17,320 --> 00:27:21,080 Speaker 1: beaming us a signal to say hi, or they might 486 00:27:21,080 --> 00:27:23,840 Speaker 1: be trying to send a signal to another alien race 487 00:27:24,119 --> 00:27:26,320 Speaker 1: or planet, and we just happen to be in the 488 00:27:26,359 --> 00:27:29,119 Speaker 1: way of the beam of the signals. The search for 489 00:27:29,240 --> 00:27:32,680 Speaker 1: signals like that have been going on for decades. 490 00:27:35,680 --> 00:27:39,520 Speaker 3: There have been a few small ish searches for decades, 491 00:27:39,720 --> 00:27:42,960 Speaker 3: starting in nineteen sixty. So with radio, which is the 492 00:27:43,000 --> 00:27:46,840 Speaker 3: most mature search technique, we use these big radio telescopes 493 00:27:46,880 --> 00:27:48,919 Speaker 3: like satellite dishes, the biggest ones you can fit a 494 00:27:48,920 --> 00:27:51,199 Speaker 3: football field inside. Of and we point them at a 495 00:27:51,240 --> 00:27:54,399 Speaker 3: nearby star and we just check to see if there's 496 00:27:54,520 --> 00:27:58,160 Speaker 3: any radio emission coming from the star. At most frequencies, 497 00:27:58,200 --> 00:28:00,359 Speaker 3: there's nothing. And if you saw that there was strong 498 00:28:00,440 --> 00:28:03,960 Speaker 3: signal just at one frequency, it's gotta be aliens. It 499 00:28:04,000 --> 00:28:07,080 Speaker 3: can't be anything else. And so there are billions of 500 00:28:07,119 --> 00:28:08,680 Speaker 3: those channels to check. 501 00:28:09,840 --> 00:28:13,560 Speaker 1: So since the nineteen sixties, scientists have been using radio 502 00:28:13,600 --> 00:28:17,000 Speaker 1: antennas to look for signals that aliens might be sending 503 00:28:17,040 --> 00:28:20,760 Speaker 1: our way, and they haven't found anything. But here's the 504 00:28:20,800 --> 00:28:23,960 Speaker 1: thing about the search for signals from aliens. A there's 505 00:28:24,000 --> 00:28:26,320 Speaker 1: a lot of sky out there to listen to, and 506 00:28:26,600 --> 00:28:29,520 Speaker 1: listening with a radio telescope is like looking at the 507 00:28:29,560 --> 00:28:33,120 Speaker 1: sky through a really thin straw. You can only see 508 00:28:33,160 --> 00:28:35,560 Speaker 1: a tiny little patch of it one at a time. 509 00:28:36,160 --> 00:28:39,480 Speaker 1: And B the US Congress really doesn't want to fund 510 00:28:39,600 --> 00:28:42,880 Speaker 1: the search for alien signals. Basically, nobody wants to be 511 00:28:42,920 --> 00:28:46,920 Speaker 1: seen as using taxpayer dollars to look for little green men. 512 00:28:47,400 --> 00:28:50,600 Speaker 1: So scientists in this field have had to basically beg 513 00:28:50,720 --> 00:28:55,280 Speaker 1: steal and borrow time on other people's radio telescopes to 514 00:28:55,400 --> 00:28:59,240 Speaker 1: do their search. They might piggybag on someone's left over time, 515 00:28:59,360 --> 00:29:03,000 Speaker 1: or they'll search for signals and data collected for other 516 00:29:03,200 --> 00:29:06,320 Speaker 1: science projects, all of which meant that they couldn't really 517 00:29:06,360 --> 00:29:09,600 Speaker 1: search very much of this guy. But recently all that 518 00:29:09,640 --> 00:29:13,200 Speaker 1: has changed thanks to a couple of Silicon Valley billionaires. 519 00:29:15,120 --> 00:29:19,120 Speaker 3: Now there's a project called Breakthrough Listen. Breakthrough Listen is 520 00:29:19,400 --> 00:29:24,080 Speaker 3: funded by Jury and Julia Milner, who are Silicon Valley billionaires. 521 00:29:24,320 --> 00:29:29,680 Speaker 3: So it's scientific philanthropy from very wealthy Silicon Valley folks. Yes, 522 00:29:29,960 --> 00:29:33,760 Speaker 3: and it's working for the first time. We're searching all 523 00:29:33,800 --> 00:29:37,040 Speaker 3: of the nearby stars for these kinds of radio signals, 524 00:29:37,240 --> 00:29:40,680 Speaker 3: and we're searching billions of channels at once. So back 525 00:29:40,680 --> 00:29:43,160 Speaker 3: in nineteen sixty they had to pick a station listen 526 00:29:43,240 --> 00:29:46,080 Speaker 3: for five minutes if they were sure they hadn't recorded anything, 527 00:29:46,200 --> 00:29:48,680 Speaker 3: you know, a little turn of the dial, go to 528 00:29:48,720 --> 00:29:51,120 Speaker 3: the next channel, listen to that one. By the seventies 529 00:29:51,120 --> 00:29:53,400 Speaker 3: they could search like twenty or one hundred of these 530 00:29:53,440 --> 00:29:55,520 Speaker 3: at once, and then by the eighties they could do 531 00:29:55,560 --> 00:29:58,480 Speaker 3: a million at once. Now we can search many billions 532 00:29:58,480 --> 00:30:01,680 Speaker 3: of channels at once. It's not me, but the Breakthrough 533 00:30:01,680 --> 00:30:04,400 Speaker 3: Listening Project has a lot of time on some of 534 00:30:04,440 --> 00:30:06,760 Speaker 3: the biggest telescopes in the world. And so that's why 535 00:30:06,800 --> 00:30:08,960 Speaker 3: I say in the last five years we've done more 536 00:30:09,000 --> 00:30:12,680 Speaker 3: searching than we've done in the previous sixty that's amazing. 537 00:30:13,200 --> 00:30:14,719 Speaker 1: And so what have they found? 538 00:30:15,120 --> 00:30:17,680 Speaker 3: And so for the first time we can actually say 539 00:30:17,720 --> 00:30:20,440 Speaker 3: there are not strong beacons coming from the very nearest 540 00:30:20,440 --> 00:30:21,640 Speaker 3: stars at these frequencies. 541 00:30:22,360 --> 00:30:25,880 Speaker 1: Yeah, they still haven't found anything, but a doctor Wright 542 00:30:25,960 --> 00:30:29,400 Speaker 1: says that doesn't mean aliens don't exist or that they're 543 00:30:29,440 --> 00:30:33,400 Speaker 1: not trying to talk to us. That is a common misconception. 544 00:30:34,360 --> 00:30:37,760 Speaker 3: Yeah, the biggest one is we've been looking for radio 545 00:30:37,800 --> 00:30:42,000 Speaker 3: waves for sixty years. Surely you know it's time to 546 00:30:42,000 --> 00:30:43,920 Speaker 3: give up, or surely they're not out there, or surely 547 00:30:43,920 --> 00:30:47,000 Speaker 3: we should try something else. It's true that for sixty 548 00:30:47,360 --> 00:30:50,680 Speaker 3: seventy years we've been looking for radio waves, but we've 549 00:30:50,720 --> 00:30:53,960 Speaker 3: barely been looking. The sky is huge, The galaxy has 550 00:30:53,960 --> 00:30:57,080 Speaker 3: one hundred billion stars, and there's billions of channels to check, 551 00:30:57,560 --> 00:30:59,400 Speaker 3: and we don't know when they might be transmitting it. 552 00:30:59,440 --> 00:31:01,520 Speaker 3: So the fact that we've been looking so long and 553 00:31:01,600 --> 00:31:04,920 Speaker 3: haven't found anything yet doesn't actually tell us if they're 554 00:31:04,960 --> 00:31:05,560 Speaker 3: there or not. 555 00:31:06,800 --> 00:31:09,040 Speaker 1: All Right, this has been a pretty big topic to 556 00:31:09,120 --> 00:31:12,040 Speaker 1: tackle in one episode. I mean, I didn't even get 557 00:31:12,080 --> 00:31:14,800 Speaker 1: to aliens shooting lasers at us to get our attention. 558 00:31:16,000 --> 00:31:20,560 Speaker 1: That's another scenario scientists are seriously exploring. So if you 559 00:31:20,640 --> 00:31:22,560 Speaker 1: want to hear me go a little bit deeper with 560 00:31:22,640 --> 00:31:25,680 Speaker 1: an anthropologist, but what it would mean for us to 561 00:31:25,720 --> 00:31:28,760 Speaker 1: find alien life, tune in on Friday when we release 562 00:31:28,880 --> 00:31:32,680 Speaker 1: a bonus mini episode. We'll talk about what people think 563 00:31:32,800 --> 00:31:35,760 Speaker 1: aliens might look like and whether finding out that aliens 564 00:31:35,800 --> 00:31:40,320 Speaker 1: exist will make anyone freak out or live their lives 565 00:31:40,360 --> 00:31:43,480 Speaker 1: any different. So come back Friday for that. But I'll 566 00:31:43,560 --> 00:31:46,200 Speaker 1: end this episode with a question I asked doctor Wright, 567 00:31:46,640 --> 00:31:49,560 Speaker 1: which is, if we did get a signal from aliens, 568 00:31:49,920 --> 00:31:51,760 Speaker 1: what does he think it will say? 569 00:31:53,560 --> 00:31:55,960 Speaker 3: If we get a signal, My guess is we'll just 570 00:31:56,000 --> 00:31:58,640 Speaker 3: barely know it's there. We won't know what's in it. 571 00:31:58,640 --> 00:32:01,120 Speaker 3: It's probably going to be impots possible to the code. 572 00:32:01,320 --> 00:32:05,640 Speaker 3: Like we've got dolphins chattering away, and we've got these 573 00:32:06,040 --> 00:32:09,480 Speaker 3: animal language experts that have been studying the chatter their 574 00:32:09,520 --> 00:32:12,360 Speaker 3: whole careers, and we can't really talk to them and 575 00:32:12,400 --> 00:32:14,560 Speaker 3: have a conversation for a lot of reasons. 576 00:32:14,720 --> 00:32:17,240 Speaker 1: And we haven't even seen that interesting in pugging two Dolphins. 577 00:32:17,520 --> 00:32:18,520 Speaker 3: Yeah, exactly. 578 00:32:18,680 --> 00:32:20,600 Speaker 1: So I think that first single is going to say 579 00:32:20,720 --> 00:32:22,479 Speaker 1: with this new phone. 580 00:32:23,440 --> 00:32:25,600 Speaker 3: You know, it's an old idea in SETI that the 581 00:32:25,640 --> 00:32:28,200 Speaker 3: first signal will get will be something we sent out. 582 00:32:28,280 --> 00:32:30,959 Speaker 3: It's their way of saying hello, like they let us 583 00:32:31,000 --> 00:32:33,960 Speaker 3: know that they got our radio transmissions and so they 584 00:32:34,040 --> 00:32:36,000 Speaker 3: echo it back to us. But I love the idea 585 00:32:36,040 --> 00:32:38,840 Speaker 3: that they're actually quite sophisticated and they'll be all into 586 00:32:38,920 --> 00:32:40,760 Speaker 3: like our pop culture and needs. 587 00:32:42,400 --> 00:32:44,800 Speaker 1: Interesting. But in this case it'd be like fifties or 588 00:32:45,040 --> 00:32:47,040 Speaker 1: eighties pop culture. 589 00:32:47,400 --> 00:32:48,840 Speaker 3: It'd be like exactly radical. 590 00:32:48,960 --> 00:32:56,520 Speaker 1: Dude, Hank Ten, Thanks for joining us. See you Friday 591 00:32:56,560 --> 00:32:59,600 Speaker 1: for the bonus episode, and see you next Wednesday for 592 00:32:59,640 --> 00:33:07,440 Speaker 1: a new full episode. You've been listening to Science Stuff. 593 00:33:07,640 --> 00:33:11,560 Speaker 1: Production of iHeartRadio written and produced by me or Hey 594 00:33:11,640 --> 00:33:16,000 Speaker 1: ch Ham, edited by Rose Seguda, Executive producer Jerry Rowland, 595 00:33:16,160 --> 00:33:19,520 Speaker 1: an audio engineer and mixer Chandler Mace, and you can 596 00:33:19,560 --> 00:33:22,800 Speaker 1: follow me on social media. Just search for PhD Comics 597 00:33:22,840 --> 00:33:25,160 Speaker 1: and the name of your favorite platform. Be sure to 598 00:33:25,160 --> 00:33:28,480 Speaker 1: subscribe to Sign Stuff on the iHeartRadio app, Apple Podcasts, 599 00:33:28,560 --> 00:33:31,840 Speaker 1: or wherever you get your podcasts, and please tell your Friends. 600 00:33:32,200 --> 00:33:34,560 Speaker 1: We'll be back next Wednesday with another episode.