WEBVTT - Where Are All the Aliens? 0:00:00.160 --> 0:00:02.360 Hey, please take a second and leave us a review 0:00:02.440 --> 0:00:06.240 on Apple Podcasts, Spotify, or wherever you listen to the podcast. 0:00:06.920 --> 0:00:07.440 Thanks a lot. 0:00:08.520 --> 0:00:12.080 Hey, Welcome to Science Stuff, a production of iHeartRadio. I'm 0:00:12.119 --> 0:00:17.239 Horehea Champ and today we are looking for aliens. There 0:00:17.239 --> 0:00:20.680 are trillions upon trillions of stars out there with planets 0:00:20.720 --> 0:00:23.280 that are not too different from the one we're living on, 0:00:23.880 --> 0:00:27.120 which means it's very likely that there's other life out 0:00:27.160 --> 0:00:31.040 there in the universe, and that begs the question where 0:00:31.080 --> 0:00:34.440 are they? Why haven't we seen them, heard from them, 0:00:34.600 --> 0:00:37.479 or why haven't they come here. We're going to talk 0:00:37.520 --> 0:00:40.280 to three scientists who've worked on the search for alien 0:00:40.320 --> 0:00:42.920 life and we're going to hear whether they think it's 0:00:43.080 --> 0:00:46.280 likely we'll ever find it. So get ready to leave 0:00:46.320 --> 0:00:49.000 Earth as we cast our eyes and ears to the 0:00:49.040 --> 0:00:52.640 cosmos to answer the question where are all the aliens? 0:00:58.920 --> 0:00:59.120 Hey? 0:00:59.120 --> 0:01:01.760 Everyone, all right, I'm just gonna come out and say it. 0:01:02.080 --> 0:01:06.160 I think there are aliens out there. Now, before you 0:01:06.200 --> 0:01:10.160 think I'm some crazy conspiracy theorists, hear me out. There 0:01:10.200 --> 0:01:14.000 are one hundred billion stars in our galaxy and at 0:01:14.080 --> 0:01:18.679 least that many galaxies in the observable universe. Scientists estimate 0:01:18.720 --> 0:01:22.000 that about one in ten stars has a planet that's 0:01:22.160 --> 0:01:26.479 like Earth, rocky and toasty enough to support life as 0:01:26.480 --> 0:01:29.559 we know it. This means there are at least one 0:01:29.880 --> 0:01:34.199 six tillion or one, followed by twenty one zeros Earth 0:01:34.319 --> 0:01:38.480 like planets out there. Plus the universe is fourteen billion 0:01:38.560 --> 0:01:41.720 years old, which is a long time for lots of 0:01:41.760 --> 0:01:45.320 things to have happened. Now, if you look at life 0:01:45.319 --> 0:01:48.680 around this here on Earth, it does seem pretty special. 0:01:49.280 --> 0:01:52.600 But is it one in one sixty million. That's one 0:01:52.680 --> 0:01:56.760 followed by twenty one zeros times fourteen billion years special. 0:01:57.320 --> 0:02:00.960 I'm willing to bet that it's not, But of course 0:02:01.200 --> 0:02:05.200 we don't know yet. That is the topic of today's episode. 0:02:05.600 --> 0:02:08.360 Why don't we know? And what are we doing to 0:02:08.480 --> 0:02:11.480 find out? Now? The search for life outside of our 0:02:11.520 --> 0:02:15.800 planet can be basically split into two. One is the 0:02:15.840 --> 0:02:19.679 search for basic life, meaning are there bacteria like life 0:02:19.720 --> 0:02:23.320 forms and the moons of Jupiter or simple organisms in 0:02:23.360 --> 0:02:27.480 the atmosphere of distant planets? And two is the search 0:02:27.680 --> 0:02:32.000 for intelligent life. Are there little green beings in flying 0:02:32.040 --> 0:02:37.360 saucers or vast civilizations with advanced technology? So in today's 0:02:37.400 --> 0:02:40.880 episode we'll tackle these one at a time. First we'll 0:02:40.880 --> 0:02:43.720 talk about the search for basic life, and then we'll 0:02:43.720 --> 0:02:46.959 cover the search for intelligent life, and then at the 0:02:47.080 --> 0:02:50.919 end we'll talk to an anthropologist who specializes in how 0:02:51.000 --> 0:02:55.680 people would react if we ever did find extraterrestrial life. 0:02:56.080 --> 0:02:59.440 Would we phone home, live long and prosper or fight 0:02:59.639 --> 0:03:03.239 and not go quietly into the night? And bonus points 0:03:03.280 --> 0:03:06.480 if you get all three of those movie references. All right, 0:03:06.600 --> 0:03:10.000 let's start with the search for basic life. To guide 0:03:10.080 --> 0:03:16.359 us through this, here's my chat with Professor Chris Impi. Well, 0:03:16.360 --> 0:03:17.919 thank you, doctor imp for joining us. 0:03:18.040 --> 0:03:19.680 Yes, it's good to be with you. My name is 0:03:19.720 --> 0:03:22.680 Chris Impi. I'm a professor of astronomy at the University 0:03:22.720 --> 0:03:23.440 of Arizona. 0:03:23.560 --> 0:03:25.760 I thought maybe you could start by telling us what 0:03:25.840 --> 0:03:29.040 are some of the different ways that us humans are 0:03:29.200 --> 0:03:31.640 trying to find life outside of our planet. 0:03:31.800 --> 0:03:34.680 Sure, well, you let off with where are all the aliens? 0:03:34.840 --> 0:03:37.720 So we can maybe move back to that. But that's 0:03:37.760 --> 0:03:41.000 her reprise is a question that Enrico Fermi asked well 0:03:41.000 --> 0:03:43.400 way back in nineteen fifty, where he was saying where 0:03:43.440 --> 0:03:45.920 are they? Where are all the aliens? So I think, 0:03:45.960 --> 0:03:48.520 in practical terms, mostly we're going to be talking about 0:03:48.560 --> 0:03:51.920 looking for microbial life or basic forms of life. So 0:03:51.960 --> 0:03:55.040 there are a set of strategies and they're coming to 0:03:55.080 --> 0:03:57.800 fruition now because we didn't know who were Earth like 0:03:57.880 --> 0:04:01.320 planets or habitable planets elsewhere, and now we know all 0:04:01.400 --> 0:04:04.560 of that, so it's like game on for finding life. 0:04:05.440 --> 0:04:08.040 Okay. The first thing doctor Impy wanted to caution us 0:04:08.080 --> 0:04:11.240 on the search for basic or simple life forms is 0:04:11.280 --> 0:04:14.760 that life is neither basic nor simple. 0:04:15.400 --> 0:04:17.520 If you want a biologist to wrap you on the knuckles, 0:04:17.560 --> 0:04:22.159 just say microbes are temple. So there are the people 0:04:22.200 --> 0:04:24.360 who try and create life in the lab, you know, 0:04:24.480 --> 0:04:27.599 start to generate life from simple chemical ingredients and see 0:04:27.600 --> 0:04:29.599 if they can simulate what they think happened on the 0:04:29.640 --> 0:04:32.840 Earth four billion years ago. They haven't succeeded yet. It's 0:04:32.880 --> 0:04:36.320 a very difficult lab experiment. They point to some very 0:04:36.320 --> 0:04:39.560 difficult steps that have to be followed to go from 0:04:39.600 --> 0:04:43.040 these very simple molecules of ten or twenty atoms to 0:04:43.200 --> 0:04:46.760 the first replicating molecule to the first simple cell. And 0:04:46.839 --> 0:04:47.880 cells are not simple. 0:04:48.920 --> 0:04:52.440 Doctor imp explains. There are two general places where we 0:04:52.560 --> 0:04:56.200 are looking for signs of basic life in our own 0:04:56.240 --> 0:05:00.080 backyard here in our Solar System and also outside our 0:05:00.120 --> 0:05:04.600 Solar system and planets around other stars. Now in our 0:05:04.640 --> 0:05:08.520 Solar system, there aren't that many places besides Earth that 0:05:08.600 --> 0:05:12.280 we can imagine there being life, at least life as 0:05:12.320 --> 0:05:16.000 we think is possible. Mercury and Venus are too hot, 0:05:16.560 --> 0:05:20.479 and all the planets Saturn and beyond are cold gas planets. 0:05:20.920 --> 0:05:24.000 So the main place we've been looking is Mars. 0:05:25.560 --> 0:05:27.960 So the first place to look for life is on 0:05:28.040 --> 0:05:30.880 an in near's location that you can study in detail, 0:05:30.920 --> 0:05:34.640 you know, place we've actually sent robotic probes Mars, and 0:05:34.720 --> 0:05:38.080 so Mars is still at the epicenter of very active 0:05:38.240 --> 0:05:42.680 searches for biology. So the first Mars life experiments with 0:05:42.760 --> 0:05:45.720 the Twin Viking experiments in nineteen seventies. 0:05:45.880 --> 0:05:48.400 So they sent some not robots but sort of like 0:05:48.520 --> 0:05:50.159 little base stations to Mars. 0:05:50.240 --> 0:05:53.920 Right, Yeah, and there are remarkable missions based on nineteen 0:05:53.960 --> 0:05:56.160 sixties technology. There are far ahead of their time because 0:05:56.160 --> 0:05:59.120 they actually did do life detection at two different locations 0:05:59.120 --> 0:06:02.040 on the surface. It's remarkable stuff. Yeah, think of how 0:06:02.080 --> 0:06:05.160 primitive computing was in the mid nineteen seventies. So there 0:06:05.160 --> 0:06:07.640 were landers, so they were stationary, but they had little 0:06:07.880 --> 0:06:12.000 diggers and so they scooted soil into containers and they 0:06:12.000 --> 0:06:14.480 could add water to see if something happened, to see 0:06:14.480 --> 0:06:17.200 if they could grow something or culture something, and they 0:06:17.200 --> 0:06:19.320 did mostly return negative results. 0:06:20.480 --> 0:06:23.000 So we've been looking for life on Mars since the 0:06:23.120 --> 0:06:30.159 nineteen seventies. Then we started sending rovers. 0:06:28.480 --> 0:06:31.440 And to sum up the research from the rovers of 0:06:31.520 --> 0:06:35.080 the last thirty years, they were essentially looking for potential. 0:06:35.279 --> 0:06:37.719 They were looking for organic material, They were looking for 0:06:37.960 --> 0:06:41.839 possible evidence of life in the geochemistry of rocks without 0:06:41.920 --> 0:06:45.360 actually looking for biology itself. So that was the limitation 0:06:45.520 --> 0:06:46.800 and still is the limitation. 0:06:48.000 --> 0:06:50.760 Over the last fifty years, we've been looking for the 0:06:50.800 --> 0:06:54.480 science of life on Mars because scientists are pretty sure 0:06:54.880 --> 0:06:58.960 Mars was once a lot like Earth. There were oceans 0:06:59.080 --> 0:07:02.480 and rivers and in the atmosphere, but then it all 0:07:02.600 --> 0:07:07.000 dried up and went away. Although that doesn't mean there 0:07:07.080 --> 0:07:10.120 isn't still liquid water on Mars. 0:07:10.840 --> 0:07:15.240 There's really good indirect evidence for subsurface liquid water aquifers. 0:07:15.640 --> 0:07:18.160 It comes from a variety of sources, from radar, from 0:07:18.240 --> 0:07:21.400 various things, people who've even seen little eruptions of sulf 0:07:21.440 --> 0:07:25.160 surface water rolling down gullies. So you can absolutely have 0:07:25.280 --> 0:07:28.440 liquid water under the surface, maybe ten fifty one hundred 0:07:28.520 --> 0:07:32.200 meters kilometer down. But that opens the prospect that there 0:07:32.240 --> 0:07:35.600 is life on Mars right now, not just fossilized life. 0:07:35.400 --> 0:07:39.000 Or who knows, maybe a little Martian fish possibly. 0:07:38.720 --> 0:07:41.280 Maybe slightly bigger than microbes. Yeah, if I mean, if 0:07:41.280 --> 0:07:45.120 there are subsurface pockets of ocean or sea, they could 0:07:45.120 --> 0:07:47.480 set up an ecosystem that might be more interesting than 0:07:47.520 --> 0:07:48.200 just microbes. 0:07:48.280 --> 0:07:52.560 Yeah, possibly in seeing people speculate, all right. The other 0:07:52.600 --> 0:07:55.560 places we can look for life in our Solar system 0:07:55.720 --> 0:07:58.840 are the moons of Jupiter and Saturn. 0:08:00.080 --> 0:08:03.160 Ask how many places could there be the ingredients for life, 0:08:03.200 --> 0:08:06.840 critically including liquid water in the Solar System. The answer 0:08:06.880 --> 0:08:09.920 is probably a dozen a dozen, and all the rest 0:08:10.080 --> 0:08:14.000 are giant planets moons, which are substantial worlds in their 0:08:14.040 --> 0:08:16.720 own right. The biggest moons of the giant planets are 0:08:16.720 --> 0:08:19.880 bigger than the Moon itself and almost like mercury size. 0:08:20.080 --> 0:08:23.480 They can keep liquid water under a rocky crust. 0:08:24.240 --> 0:08:26.960 What doctor MP's saying here is that in several of 0:08:27.040 --> 0:08:31.480 the moons of Jupiter and Saturn, like Europa and Enceladus, 0:08:31.880 --> 0:08:36.360 scientists believe there are huge underwater oceans that could have 0:08:36.559 --> 0:08:38.679 life in them. 0:08:38.960 --> 0:08:42.320 So Europa is a water world. It's entirely encased in 0:08:42.440 --> 0:08:46.280 ice of probably five to ten kilometers thickness, and that 0:08:46.440 --> 0:08:49.160 overlays an ocean that could be fifty to one hundred 0:08:49.200 --> 0:08:52.679 kilometers deep. It's really substantial ocean, far more water than 0:08:52.720 --> 0:08:54.920 the Earth's oceans. So people think of Earth as the 0:08:54.920 --> 0:08:57.920 water world. That's not true. There's a couple of places 0:08:57.920 --> 0:09:00.000 in the Solar System with more water than the Earth. 0:09:00.600 --> 0:09:03.319 We're sending the Europea clipper there right now. That was 0:09:03.360 --> 0:09:06.760 a successful launch just last year. It's going to make 0:09:06.920 --> 0:09:10.600 very clever orbital measurements to look for traces of life 0:09:10.600 --> 0:09:13.440 with spectroscopy and so on. It may even splash off 0:09:13.520 --> 0:09:17.280 some icy material by sending a projectile under the surface 0:09:17.320 --> 0:09:19.839 and then sniff the particles that come out. 0:09:20.120 --> 0:09:20.440 Wow. 0:09:20.600 --> 0:09:22.920 So it's not a true life detection experiment, but it's 0:09:22.960 --> 0:09:24.960 going to learn a lot more about Europa than we 0:09:25.000 --> 0:09:28.440 ever knew before. We also have Enceladus, which is a 0:09:28.480 --> 0:09:32.200 tiny moon of Saturn where the icy geysers were found 0:09:32.320 --> 0:09:35.520 ten or fifteen years ago, and those icy jets going 0:09:35.559 --> 0:09:38.760 into space also indicate there was liquid water and sell 0:09:38.840 --> 0:09:41.200 this it's irregular, it's a potato shaped, it's not even 0:09:41.240 --> 0:09:44.560 a round object could have the ingredients for life. And 0:09:44.600 --> 0:09:48.320 then the third most compelling place is Titan, so that's 0:09:48.360 --> 0:09:52.600 the biggest moon of Saturn. Titan is fascinating because it's 0:09:52.600 --> 0:09:55.760 a big moon. It has an atmosphere as thick as 0:09:55.760 --> 0:09:58.360 the Earth's, and it's made of the same stuff nitrogen, 0:09:58.559 --> 0:10:02.840 no oxygen, but nitrogen. It has weather, It has bodies 0:10:02.840 --> 0:10:08.080 of liquid and lakes and river deltas and clouds and precipitation. 0:10:08.360 --> 0:10:11.839 It has volcanism, but it's an alien world because it's 0:10:11.920 --> 0:10:15.000 very cold, and so that liquid is not water. It's 0:10:15.080 --> 0:10:18.240 ethane and methane. So the lakes on Titan are rather 0:10:18.360 --> 0:10:22.680 strange organic brood that's not mostly water. And if you 0:10:22.720 --> 0:10:26.680 ask a biologist, should you have biology in a medium 0:10:26.760 --> 0:10:30.920 that's ethane and methane as opposed to water, they scratch 0:10:30.960 --> 0:10:34.600 their heads and say, maybe you just get fanciful with 0:10:34.720 --> 0:10:38.599 hypothetical biology. Yes, you could maybe form complex molecules in 0:10:38.679 --> 0:10:40.000 that kind of a liquid medium. 0:10:41.480 --> 0:10:44.720 So to summarize, there are lots of places right here 0:10:44.760 --> 0:10:48.199 in our solar system where there could be alien life. 0:10:48.720 --> 0:10:51.640 But the problem, according to doctor imp is there's no 0:10:51.760 --> 0:10:56.600 funding to go look Sending probes or drones to landlin 0:10:56.679 --> 0:10:59.920 titen or drill under the ice or ground in Europe 0:11:00.280 --> 0:11:04.120 or Mars is expensive, and things at NASA are not 0:11:04.240 --> 0:11:07.240 looking so good right now for science funding. 0:11:08.360 --> 0:11:10.640 So the bottom line on the Solar System is, yes, 0:11:10.679 --> 0:11:12.800 there could be life elsewhere in the Solar System, but 0:11:12.960 --> 0:11:16.160 the experiments are very difficult, the timelines are long, they're 0:11:16.200 --> 0:11:20.120 expensive experiments, and some most astronomers saying the first detection 0:11:20.160 --> 0:11:23.240 of life on Earth will come by looking at excelp. 0:11:22.960 --> 0:11:27.720 Planets, planets that are in other stars, not the Sun. 0:11:27.880 --> 0:11:31.640 Right, planets orbiting other stars, of which we found thousands now, 0:11:31.840 --> 0:11:34.200 including hundreds that are roughly Earth like. 0:11:34.520 --> 0:11:37.000 Well, but if they're so far away, how can we 0:11:37.160 --> 0:11:38.640 tell if they have life. 0:11:38.840 --> 0:11:42.280 Well, the life detection experiment is just the cutting, the 0:11:42.440 --> 0:11:44.000 very cutting, bleeding edge. 0:11:44.559 --> 0:11:46.559 All right. When we come back, we'll talk about how 0:11:46.559 --> 0:11:49.960 to look for alien life in distant planets. We'll talk 0:11:49.960 --> 0:11:55.360 to another astronomer who specializes looking for intelligent alien life 0:11:55.800 --> 0:12:12.600 out there. Don't go anywhere, we'll be right back, welcome back. 0:12:14.720 --> 0:12:18.000 All right. We're talking about the search for alien life, 0:12:18.600 --> 0:12:21.160 and we're going to get to the search for intelligent 0:12:21.360 --> 0:12:24.440 alien life but first we're going to hear from Professor 0:12:24.520 --> 0:12:27.839 Chris Impi about how we're looking for the signs of 0:12:27.960 --> 0:12:34.880 basic life and planets far away outside of our Solar system. Okay, 0:12:35.400 --> 0:12:37.960 you were saying that we can use James Webb and 0:12:38.000 --> 0:12:42.200 some ground based telescopes to possibly detect life in other planets. 0:12:42.559 --> 0:12:45.400 Right, We're not taking pictures and seeing things swimming around 0:12:45.440 --> 0:12:48.720 in a in an exo ocean, or watching you know, 0:12:49.880 --> 0:12:53.600 exo dinosaurs lumbering about on a continent on a planet 0:12:53.640 --> 0:12:56.040 one hundred light years away. None of that wonderful thing. 0:12:56.160 --> 0:12:58.240 It's going to happen. It would be great, but it's 0:12:58.280 --> 0:13:01.199 some science fiction forever. So this is what you do. 0:13:01.360 --> 0:13:03.400 The idea is it's sort of based on the Earth 0:13:03.800 --> 0:13:06.840 because the air we breathe, one part in five is oxygen, 0:13:06.920 --> 0:13:09.800 and that oxygen was put there by microbes mostly billions 0:13:09.800 --> 0:13:12.959 of years ago, and that oxygen is the telltale as 0:13:13.080 --> 0:13:15.240 for someone looking at the Earth from far away, that 0:13:15.280 --> 0:13:17.720 the Earth is a living planet, even if they couldn't 0:13:17.720 --> 0:13:18.520 see anything else. 0:13:19.320 --> 0:13:22.559 What doctor MP is saying here is that planets outside 0:13:22.600 --> 0:13:25.680 our Solar System are too far away for us to 0:13:25.800 --> 0:13:28.880 really take a picture of them. The closest planet to 0:13:29.000 --> 0:13:32.560 us out there is orbiting a star called Proxima Centauri, 0:13:32.920 --> 0:13:36.800 four point twenty five light years or twenty five trillion 0:13:36.840 --> 0:13:40.440 miles away. Not even our best telescopes can get a 0:13:40.520 --> 0:13:43.040 clear enough view of them to tell if they have 0:13:43.200 --> 0:13:46.160 life on them. So the main way we're looking for 0:13:46.320 --> 0:13:50.880 basic life in other planets is by studying their atmosphere. 0:13:51.360 --> 0:13:54.160 That we can do by looking at the light they reflect. 0:13:54.440 --> 0:13:57.080 And once your sign of life is having a lot 0:13:57.120 --> 0:13:58.720 of oxygen. 0:13:59.600 --> 0:14:03.079 Imagine the biosphere the whole life on our shuts down overnight, 0:14:03.200 --> 0:14:05.959 within a few million years, the oxygen will be gone. 0:14:06.360 --> 0:14:08.599 It would bind with rock, it would rust things, it 0:14:08.600 --> 0:14:11.280 would dissolve in the oceans, and it would disappear because 0:14:11.280 --> 0:14:15.200 it's sustained by life. So the reverse logic is that 0:14:15.240 --> 0:14:18.200 if you see oxygen in the planet, that's a good 0:14:18.320 --> 0:14:21.840 sign that there's biology on that planet. So oxygen in 0:14:21.880 --> 0:14:26.440 that way is what's called a biomarker or biosignature by astrobiologists. 0:14:26.520 --> 0:14:28.400 So methane is a biomarker too. 0:14:29.520 --> 0:14:34.080 The study of potential life in other planets is called astrobiology. 0:14:34.600 --> 0:14:37.400 Now we have been able to see faint signs of 0:14:37.440 --> 0:14:40.480 the atmosphere and far away planets. But it's such a 0:14:40.520 --> 0:14:43.200 hard problem. We haven't been able to do it in 0:14:43.280 --> 0:14:45.280 the right kind of planet. 0:14:46.480 --> 0:14:49.160 They've proved that you can sniff the atmosphere of an 0:14:49.160 --> 0:14:52.520 exoplanet and say what's in it, but they've been done 0:14:52.560 --> 0:14:56.560 for more massive planets, more like neptunes and urinous type 0:14:56.560 --> 0:15:00.440 planets gas giants, not growth like terrestrial planets. So it's 0:15:00.560 --> 0:15:03.640 just just too hard. And then the question is how 0:15:03.640 --> 0:15:06.080 can we do better? And then we have to wait 0:15:06.120 --> 0:15:09.840 for this next generation of three large telescopes all under construction. 0:15:10.920 --> 0:15:13.280 So that's where we are in the search for basic 0:15:13.360 --> 0:15:16.680 life out there in our Solar system. We need to 0:15:16.760 --> 0:15:20.560 fund better, more complicated missions to go out there and 0:15:20.640 --> 0:15:24.600 bring back samples from Mars or the Moon's Europa or 0:15:24.720 --> 0:15:28.720 Titan and beyond our Solar system. We need better telescopes 0:15:29.000 --> 0:15:31.120 just to get a whiff of the science of life 0:15:31.320 --> 0:15:35.360 in the atmosphere of distant planets. And that brings us 0:15:35.360 --> 0:15:38.840 to the search for intelligent life out there, and for 0:15:38.920 --> 0:15:42.560 that we might not need such fancy equipment because we 0:15:42.640 --> 0:15:45.000 might not need to go looking for it. It might 0:15:45.440 --> 0:15:48.960 come to us to guide us through this possibility. I 0:15:49.080 --> 0:15:51.480 reached out to Professor Jason Wright. 0:15:53.200 --> 0:15:56.680 I am Jason Right, a professor of astronomy and astrophysics 0:15:56.720 --> 0:15:59.680 at Penn State, and I'm also the director of the 0:15:59.680 --> 0:16:04.040 Penn State Extraterrestrial Intelligence Center, where we look at all 0:16:04.080 --> 0:16:07.360 aspects of the search for intelligent life in the universe. 0:16:07.560 --> 0:16:11.040 Amazing and just adult check. You're not an alien yourself? 0:16:11.080 --> 0:16:12.080 Are you not? 0:16:12.240 --> 0:16:15.440 As far as I know, Yes, yes, I'm not. 0:16:15.480 --> 0:16:16.760 I mean, oh, that would be a good plot to 0:16:16.880 --> 0:16:20.280 this if the director of the search for intelligence turned 0:16:20.280 --> 0:16:22.040 out to be an alien but he didn't know didn't 0:16:22.080 --> 0:16:22.360 know it? 0:16:22.440 --> 0:16:26.040 Right, Yeah, all right. 0:16:26.160 --> 0:16:28.320 The first thing that they're right. I wanted to clarify 0:16:28.400 --> 0:16:32.080 for us is that looking for intelligence out there in 0:16:32.120 --> 0:16:35.280 the universe is kind of the wrong way to go 0:16:35.320 --> 0:16:37.120 about it. 0:16:37.680 --> 0:16:40.480 So we use the word intelligence a little loosely. We 0:16:40.520 --> 0:16:42.880 don't mean it in a literal sense of intelligence. What 0:16:42.960 --> 0:16:46.120 we're looking for is technology because we imagine that it 0:16:46.200 --> 0:16:49.960 might be much easier to find signs of technology across 0:16:50.000 --> 0:16:52.160 the stars than signs of life. 0:16:52.520 --> 0:16:55.400 Now, why do you draw this distinction between intelligence and technology? 0:16:55.440 --> 0:16:57.480 Isn't it sort of the same? Like put in one 0:16:57.480 --> 0:16:58.200 imply the other. 0:16:58.440 --> 0:17:01.000 We try to be really careful with that word intelligence. 0:17:01.200 --> 0:17:03.640 The word intelligence gets used in a lot of ways, like, 0:17:03.720 --> 0:17:07.440 you know, if you're looking at a culture that never 0:17:07.560 --> 0:17:12.280 developed radio transmitters, are they not intelligent? You know, we 0:17:12.320 --> 0:17:15.600 don't want to equate certain kinds of technology with a 0:17:15.640 --> 0:17:18.280 much broader and squisher concept of intelligencing. 0:17:19.240 --> 0:17:21.919 What doctor Wright is saying is that what you're doing 0:17:22.040 --> 0:17:25.040 when you say you're looking for aliens, is you're really 0:17:25.080 --> 0:17:29.480 looking for signs of technology, because there could be perfectly 0:17:29.520 --> 0:17:32.720 intelligent aliens out there, but we may never see them 0:17:32.920 --> 0:17:35.920 if they don't use technology that tells us they're there. 0:17:36.440 --> 0:17:39.879 For example, Earth had intelligent life on it for thousands 0:17:39.920 --> 0:17:43.679 of years before we even invented the light bulb. Or 0:17:43.800 --> 0:17:48.120 think about whales or dolphins. They're intelligent, but an alien 0:17:48.160 --> 0:17:51.760 species far away looking at Earth might never know they're 0:17:51.920 --> 0:17:52.520 even here. 0:17:53.560 --> 0:17:56.240 In fact, there have been many proposed alternative names for 0:17:56.280 --> 0:17:58.520 this field. Freeman Dyson said it should be called the 0:17:58.520 --> 0:18:02.960 Search for Extraterrestrial Technology, which would be set tea and 0:18:03.240 --> 0:18:06.359 Jill Tarter, who looks for radio waves, said, you know, 0:18:06.359 --> 0:18:09.080 I'm not going to detect any intelligence except that that 0:18:09.200 --> 0:18:12.520 went into building a radio transmitter, which is electrical engineering. 0:18:12.600 --> 0:18:16.680 So she joked it was a search for extraterrestrial electrical engineers, 0:18:17.119 --> 0:18:20.280 which is also set easy fit. Yeah, so as long 0:18:20.320 --> 0:18:22.760 as you just say SETI, you're you're good. 0:18:23.840 --> 0:18:26.520 Okay, this is kind of a semantic argument. What you 0:18:26.600 --> 0:18:30.160 really want to know is where are the smart aliens? Well, 0:18:30.240 --> 0:18:32.400 the way that their right breaks it down is that 0:18:32.480 --> 0:18:35.440 there are really only three ways in which we'll ever 0:18:35.760 --> 0:18:40.560 have confirmation of intelligent life out there. We're not traveling 0:18:40.560 --> 0:18:43.760 to other stars anytime soon, so the only ways left 0:18:44.000 --> 0:18:47.600 are a if we see signs of their technology from here, 0:18:48.160 --> 0:18:51.800 b if they come visit us and see if they're 0:18:51.800 --> 0:18:54.560 trying to talk to us, or if we happen to 0:18:54.640 --> 0:19:00.000 catch them talking to other aliens. Now, let's be clear, 0:19:00.359 --> 0:19:03.680 none of these things have happened. We haven't noticed any 0:19:03.720 --> 0:19:07.560 alien civilizations out there. We haven't been visited by aliens 0:19:07.800 --> 0:19:10.560 as far as I know, despite what you might have heard, 0:19:10.840 --> 0:19:13.840 and we haven't received a call from an alien yet. 0:19:14.359 --> 0:19:14.879 Why is that? 0:19:16.320 --> 0:19:19.800 As I mentioned before, there are trillions of stars and 0:19:20.040 --> 0:19:23.280 plenty of time in the universe. If there are aliens 0:19:23.320 --> 0:19:26.520 out there, surely one of these things would have happened 0:19:26.600 --> 0:19:30.880 by now. And this is what's known as the Fermi paradox. 0:19:31.800 --> 0:19:34.480 So there's this idea called the Fermi paradox, and it 0:19:34.520 --> 0:19:38.360 goes like this. Enrico Fermi was a famous physicist, and 0:19:38.560 --> 0:19:41.359 in nineteen fifty, before we even started looking, they were 0:19:41.400 --> 0:19:44.760 talking about UFOs and he realized the galaxy is so 0:19:45.000 --> 0:19:49.320 old that even with just normal rockets, it would only 0:19:50.119 --> 0:19:53.480 take millions of years to get every anywhere you wanted 0:19:53.520 --> 0:19:55.440 to go in the galaxy. And since the galaxy is 0:19:55.480 --> 0:19:58.719 billions of years old, there's plenty of time for them 0:19:58.760 --> 0:20:01.480 to have gotten here by now, even without warp drive. 0:20:03.119 --> 0:20:07.280 So where is everybody? Sometimes this gets phrased as we 0:20:07.359 --> 0:20:09.919 expect them to be out there, why haven't we found 0:20:09.960 --> 0:20:14.240 them yet? That's the Fermi paradox. And I should say 0:20:14.359 --> 0:20:17.199 there have been whole papers written on why it's not 0:20:17.520 --> 0:20:21.200 really a paradox, because we haven't yet real doubt that 0:20:21.240 --> 0:20:24.119 there are no aliens. But the point is it's a 0:20:24.119 --> 0:20:27.639 big question that is puzzling. Where are all the aliens? 0:20:27.960 --> 0:20:30.760 And here doctor Wright thinks he has an answer. 0:20:31.760 --> 0:20:36.160 The whole Fermi paradox thing is badly misunderstood because it's 0:20:36.200 --> 0:20:38.520 not really a puzzle, Like, none of us doing this 0:20:38.600 --> 0:20:39.800 work are worried about it. 0:20:40.960 --> 0:20:44.720 Meaning you have an explanation for why we haven't themed 0:20:44.960 --> 0:20:50.200 or found or been visited by any aides. Yeah, okay, 0:20:50.280 --> 0:20:53.160 we're going to tackle each scenario in well we Aliens 0:20:53.359 --> 0:20:57.720 one by one, starting with why haven't any aliens come 0:20:58.000 --> 0:21:02.120 visit us? Well, let's say, and I'm asking you, why 0:21:02.160 --> 0:21:04.280 haven't we've been visited by any aliens? 0:21:04.480 --> 0:21:07.280 I would say there's a lot of reasons. So my 0:21:07.480 --> 0:21:12.160 favorite is that we're here we haven't been visited by 0:21:12.240 --> 0:21:15.919 other species, perhaps exactly because Earth has life, and so 0:21:16.160 --> 0:21:18.120 maybe they've come through the Solar system and they've seen 0:21:18.160 --> 0:21:20.080 the Earth has life, and maybe they've you know, gone, oh, 0:21:20.080 --> 0:21:21.639 that's kind of interesting. But they're just going to leave 0:21:21.680 --> 0:21:25.320 us alone and not land and invade and like try 0:21:25.359 --> 0:21:28.320 and take the place over because it's got life. That's 0:21:28.359 --> 0:21:29.240 my favorite answer. 0:21:30.080 --> 0:21:33.800 So one possibility for why aliens haven't visited us is 0:21:34.520 --> 0:21:37.919 maybe they have they just chose to leave us alone. 0:21:38.280 --> 0:21:40.239 It's sort of like if you're on a hike and 0:21:40.280 --> 0:21:42.560 you see an ant hill or you see a bear, 0:21:42.880 --> 0:21:45.639 you don't run up to the ants or the bear screaming, 0:21:45.920 --> 0:21:48.120 planting a flag where they live and try to teach 0:21:48.160 --> 0:21:51.920 them about people, you just let them be. So maybe 0:21:52.000 --> 0:21:55.119 aliens have been here, but they just moved on. 0:21:57.200 --> 0:22:00.240 Another answer is spaceflight is just really hard. It's very, very, 0:22:00.359 --> 0:22:02.919 very hard to build a machine that can last the 0:22:03.000 --> 0:22:05.800 hundreds of thousands of years or millions of years it 0:22:05.840 --> 0:22:08.199 would take to go to another star, and it's just 0:22:08.200 --> 0:22:11.160 not worth it that no species ever does it more 0:22:11.200 --> 0:22:13.919 than a couple of times tops, And so they haven't 0:22:14.080 --> 0:22:18.440 visited every single star in the galaxy because interstellar flight 0:22:18.560 --> 0:22:20.720 is just too hard and requires machines that would have 0:22:20.720 --> 0:22:21.520 to last too long. 0:22:22.680 --> 0:22:25.760 Another reason we haven't been visited by aliens is that 0:22:25.840 --> 0:22:29.919 maybe space travel is too hard. Maybe warp drives are 0:22:30.080 --> 0:22:32.800 just to fantasy, and the reality is that it takes 0:22:32.960 --> 0:22:37.160 hundreds or thousands of years to go visit other star systems, 0:22:37.480 --> 0:22:41.240