WEBVTT - Rerun: Seti Not At Home 0:00:04.480 --> 0:00:12.840 Welcome to tech Stuff, a production from iHeartRadio. Hey theren 0:00:12.920 --> 0:00:16.360 Welcome to tech Stuff. I'm your host, Jonathan Strickland. I'm 0:00:16.360 --> 0:00:19.799 an executive producer with iHeart Podcasts and how the tech 0:00:19.960 --> 0:00:24.640 are you well. I am finishing up my vacation down 0:00:24.680 --> 0:00:28.680 in floridaar and I will be back in Atlanta next week. 0:00:29.000 --> 0:00:31.040 In the meantime, I do have an episode for you. 0:00:31.120 --> 0:00:34.600 This one published on March eleventh, twenty twenty. It is 0:00:34.640 --> 0:00:38.760 titled SETI Not at Home. It's about the SETI at 0:00:38.760 --> 0:00:44.800 Home program, a program that crowdsourced the search for extraterrestrial intelligence, 0:00:45.320 --> 0:00:49.720 and why it shut down in March of twenty twenty. 0:00:50.240 --> 0:00:53.680 At least the crowdsource part. The program itself has not 0:00:53.840 --> 0:00:56.760 shut down, to be clear, but the crowdsource part has. 0:00:57.200 --> 0:01:00.960 Let's find out why. As I record, it is early 0:01:01.200 --> 0:01:08.160 March twenty twenty, just days after I received some devastating news. Technically, 0:01:08.520 --> 0:01:11.200 the whole world received this news. I'm just taking it 0:01:11.240 --> 0:01:15.600 particularly hard. I heard that the distributed computing project SETI 0:01:15.720 --> 0:01:19.800 at Home is shutting down, at least for a while. 0:01:19.959 --> 0:01:23.280 It's going on hiatus by the end of March twenty twenty. 0:01:23.880 --> 0:01:27.280 Now for two decades. This project has been relying on 0:01:27.319 --> 0:01:31.640 computer processing cycles provided by people like all of you 0:01:31.680 --> 0:01:35.440 guys out there, just using regular computer processors rather than 0:01:35.480 --> 0:01:40.280 some sort of massive supercomputer. Why was it making use 0:01:40.319 --> 0:01:43.760 of that, Well, it was coming through massive amounts of 0:01:43.800 --> 0:01:47.600 information gathered by radio telescopes in search for signals created 0:01:47.800 --> 0:01:54.000 not through some natural cosmological process, but rather as evidence 0:01:54.240 --> 0:01:59.880 of intelligent communication. SETI, you see, stands for the search 0:02:00.120 --> 0:02:04.520 for extraterrestrial intelligence. Now, in this episode, I'm going to 0:02:04.560 --> 0:02:08.280 talk about the history of SETI as a science, and 0:02:08.320 --> 0:02:10.800 then as well, I'm going to kind of pivot around 0:02:10.840 --> 0:02:14.480 and talk about the distributed computer programs and the SETI 0:02:14.520 --> 0:02:18.080 at Home program in particular. We'll find out how distributed 0:02:18.080 --> 0:02:20.840 computing works, we'll talk about a couple of other distributed 0:02:20.880 --> 0:02:23.400 computing programs that you could still participate in if you're 0:02:23.400 --> 0:02:26.720 so inclined, And we'll also look into what's next for 0:02:26.840 --> 0:02:29.959 SETI at Home and learn why it's going on hiatus 0:02:30.000 --> 0:02:35.040 in the first place. Now, we human beings have hypothesized 0:02:35.080 --> 0:02:40.160 about the possibility of extraterrestrial or alien intelligence for a 0:02:40.160 --> 0:02:44.040 really long time. It's a frequent topic in pop culture. 0:02:44.880 --> 0:02:48.320 But perhaps I shouldn't even use the word hypothesize, because 0:02:48.360 --> 0:02:51.640 for a really long time in our history, there really 0:02:51.680 --> 0:02:54.800 wasn't any way to test that hypothesis other than for 0:02:54.880 --> 0:02:58.400 us to look up at the sky and say, Nope, 0:02:58.440 --> 0:03:02.160 that ain't it. That would all change with the invention 0:03:02.400 --> 0:03:06.359 of the radio telescope. So it was in the nineteen 0:03:06.480 --> 0:03:10.679 twenties when an engineer named Karl Janski, working for Bell 0:03:10.840 --> 0:03:15.560 Telephone Laboratories, set the stage for radio astronomy. But that 0:03:15.639 --> 0:03:18.920 wasn't Jansky's goal at the time. He had been tasked 0:03:19.160 --> 0:03:22.640 with figuring out where the source was of some signal 0:03:22.680 --> 0:03:27.160 interference that was affecting telephone communications at that time. So 0:03:27.400 --> 0:03:30.200 in an effort to kind of figure this out, he 0:03:30.240 --> 0:03:34.040 built a directional antenna. And I guess that itself deserves 0:03:34.080 --> 0:03:39.240 its own quick explanation. So antennas can transmit and pick 0:03:39.320 --> 0:03:42.119 up signals, right, I mean, that's what they do, And 0:03:42.160 --> 0:03:46.040 it actually helps to talk about transmitters first to understand 0:03:46.080 --> 0:03:50.560 how a receiving antenna works. So a transmitter takes an 0:03:50.600 --> 0:03:55.960 electrical signal, typically one that's been boosted with amplification, and 0:03:56.480 --> 0:04:00.440 sends that signal to a transmitting antenna. We know that 0:04:00.480 --> 0:04:04.360 electricity and magnetism are related, right. We've talked about that 0:04:04.880 --> 0:04:08.680 a ton in previous episodes, and we've talked about electromagnetism 0:04:08.760 --> 0:04:13.640 and the electromagnetic spectrum a lot on this show, even recently. So, 0:04:14.240 --> 0:04:17.640 if you run a current through a conductor, it generates 0:04:17.640 --> 0:04:22.360 electromagnetic waves, including if the conductor's big enough, radio waves. 0:04:23.200 --> 0:04:26.760 Now on the electromagnetic spectrum, radio waves have the longest 0:04:26.800 --> 0:04:30.359 wavelengths if you look across that spectrum. They are a 0:04:30.520 --> 0:04:34.080 non ionizing form of radiation, meaning they lack the power 0:04:34.120 --> 0:04:37.920 to strip electrons away from atoms, and they aren't harmful 0:04:38.240 --> 0:04:40.520 the way stuff like X rays or gamma rays are. 0:04:40.640 --> 0:04:45.039 So you can wander around and have radio waves hitting you. 0:04:45.160 --> 0:04:47.160 It's not going to affect you in any way. You 0:04:47.200 --> 0:04:51.839 won't even notice. Okay, So, sending a powerful electrical current 0:04:52.160 --> 0:04:57.159 through a big conductor generates radio waves along with other 0:04:57.200 --> 0:05:04.279 electromagnetic radiation code information on radio waves by altering that 0:05:04.360 --> 0:05:08.240 signal in some way. Otherwise you're just sending out a long, 0:05:08.440 --> 0:05:12.200 steady tone like a sin wave. The two main ways 0:05:12.240 --> 0:05:15.880 to do this are frequency modulation, in which you change 0:05:15.920 --> 0:05:18.719 the frequency of the radio waves that you're sending out 0:05:18.839 --> 0:05:22.880 within a certain band of frequencies, or amplitude modulation in 0:05:22.920 --> 0:05:25.200 which you change the amplitude, or you can think of 0:05:25.200 --> 0:05:27.839 it as almost like the strength of the radio waves 0:05:27.839 --> 0:05:31.679 that you're sending out. That would end up being FM 0:05:31.760 --> 0:05:36.360 and AM radio respectively. All right, So receivers take that 0:05:36.480 --> 0:05:40.039 same process, but they reverse it. So as long as 0:05:40.080 --> 0:05:44.080 the signals that the antenna pickup are fluctuating in some way, 0:05:44.640 --> 0:05:48.599 then it's going to create an electric current in that antenna. 0:05:48.880 --> 0:05:53.880 So a properly tuned receiver that encounters the respective radio 0:05:53.920 --> 0:05:57.760 wave radiation will see that whole process go in reverse. 0:05:57.839 --> 0:06:00.839 The radio waves will induce electricity to flow through the 0:06:00.880 --> 0:06:03.800 antenna to whatever device the antenna's hooked up to. It 0:06:03.880 --> 0:06:05.919 might be a meter, in which case you'll see the 0:06:05.920 --> 0:06:09.960 little indicator show that there's a current running through that circuit. 0:06:11.200 --> 0:06:14.400 Or it'll be a radio so that you can listen 0:06:14.440 --> 0:06:17.080 to a radio station that way. Could be any number 0:06:17.160 --> 0:06:20.799 of things. It usually will require amplification of that signal. 0:06:20.960 --> 0:06:25.440 Typically the signal is too weak to actually power anything significant, 0:06:25.680 --> 0:06:27.880 so you would run it through an amplifier and thus 0:06:28.040 --> 0:06:31.000 take that same signal and just boost its power before 0:06:31.040 --> 0:06:33.080 sending it on to do whatever it was supposed to do. 0:06:33.600 --> 0:06:38.640 Now I've dramatically simplified this whole process. There's other stuff 0:06:38.640 --> 0:06:41.600 we could talk about that really plays an important part, 0:06:41.680 --> 0:06:45.640 like the concept of resonance, but that is really the 0:06:45.680 --> 0:06:48.760 matter for a different episode entirely, and I have covered 0:06:48.760 --> 0:06:53.839 it in previous episodes too. So essentially that's how antennas work. 0:06:54.000 --> 0:06:58.080 So Janski designed a directional antenna as opposed to an 0:06:58.080 --> 0:07:02.359 omnidirectional antenna. An omni directional antenna, as the name implies, 0:07:02.440 --> 0:07:06.200 can pick up signals transmitted from any direction from around 0:07:06.240 --> 0:07:09.640 that antenna. Like just imagine an antenna poking up straight 0:07:09.640 --> 0:07:12.720 in the air and it can accept radio waves from 0:07:12.760 --> 0:07:17.600 any direction. Now, a directional antenna is designed in such 0:07:17.600 --> 0:07:21.840 a way where it is much more sensitive at picking 0:07:21.960 --> 0:07:24.800 up signals that are coming from specific points. You have 0:07:24.840 --> 0:07:28.760 to point the antenna toward the area where you expect 0:07:29.000 --> 0:07:32.040 there to be a radio wave, and the benefit is 0:07:32.440 --> 0:07:35.600 you can pick up much weaker radio waves typically with 0:07:35.680 --> 0:07:38.840 a directional antenna than with an omni directional antenna. However, 0:07:39.320 --> 0:07:42.160 if you're a couple of degrees off, if your antenna 0:07:42.240 --> 0:07:45.720 is not pointed directly at the source, you may not 0:07:45.800 --> 0:07:48.240 pick up the signal at all. So if you have 0:07:48.360 --> 0:07:51.840 the directional antenna pointed north, for example, but the source 0:07:51.880 --> 0:07:54.800 of radio waves is to the west, then your antenna 0:07:54.880 --> 0:07:57.480 might not pick it up because it's pointed in a 0:07:57.520 --> 0:08:01.440 different direction. However, this is it's an incredibly useful tool 0:08:02.080 --> 0:08:07.720 if you're trying to look for a specific source of 0:08:08.120 --> 0:08:11.880 interference in your telephone communication system. I should also add 0:08:12.280 --> 0:08:16.320 that there's another important thing about directional antennas is that 0:08:17.080 --> 0:08:19.840 even they have a limit to how far they can 0:08:19.880 --> 0:08:23.440 pick up a signal here on Earth. And this has 0:08:23.480 --> 0:08:26.560 to do with the fact that our Earth is and 0:08:26.680 --> 0:08:32.319 brace yourselves round, it's not a flat earth, people. The 0:08:32.360 --> 0:08:35.800 way radio waves propagate and it can be transmitted and received, 0:08:36.200 --> 0:08:39.280 that alone would tell us that the Earth has to 0:08:39.320 --> 0:08:42.920 be curved. And here's the reason. When you broadcast radio waves, 0:08:43.080 --> 0:08:46.160 they travel outward in a straight line from the source 0:08:46.280 --> 0:08:50.760 of radiation. And if the Earth were flat, then no 0:08:50.800 --> 0:08:52.640 matter how far away you were, if you had a 0:08:52.679 --> 0:08:55.520 sensitive enough antenna, you'd be able to pick up radio 0:08:55.559 --> 0:09:00.240 waves from that source. However, because the Earth curves, then 0:09:00.000 --> 0:09:03.280 and you look at two different points on the planet 0:09:03.360 --> 0:09:06.439 that are far enough apart that curvature means that if 0:09:06.480 --> 0:09:09.360 you're having radio waves travel out at a straight line 0:09:09.360 --> 0:09:12.440 from point A, they won't reach point B because it's 0:09:12.480 --> 0:09:16.360 curved away from the path right, It'll those radio waves 0:09:16.400 --> 0:09:20.640 will just go out into space instead. There is an 0:09:20.679 --> 0:09:23.960 exception to this, and that certain radio waves are the 0:09:24.080 --> 0:09:27.280 right length where they can bounce off the Earth's ion 0:09:27.320 --> 0:09:30.440 a sphere. So you can use the ionosphere sort of 0:09:30.480 --> 0:09:33.720 like a mirror. You can point radio waves toward it. 0:09:33.720 --> 0:09:37.000 It will bounce off the ionosphere and then angle back 0:09:37.160 --> 0:09:39.959 down toward the surface of the Earth. That way, you 0:09:40.000 --> 0:09:43.719 could actually transmit much further than you could just from 0:09:43.840 --> 0:09:45.920 line of sight. You can think of it as a 0:09:45.920 --> 0:09:47.360 line of sight. You don't even actually have to be 0:09:47.400 --> 0:09:48.960 able to see the thing. It just has to be, 0:09:49.400 --> 0:09:52.559 like I said, a more or less straight path from 0:09:52.640 --> 0:09:54.959 point A to point B for you to pick it up. Okay, 0:09:54.960 --> 0:09:59.400 but that's beside the point. Janski's antenna was a directional 0:09:59.440 --> 0:10:06.880 antenna meant to pick up that source of interference. So 0:10:08.040 --> 0:10:12.720 he's picking up weird signals as he's using this directional 0:10:12.760 --> 0:10:17.280 antenna that don't seem to have any terrestrial source to them, 0:10:17.640 --> 0:10:20.880 Like if he pointed the directional antenna up into the air. 0:10:21.320 --> 0:10:23.720 He was picking up signals, but he could not identify 0:10:23.760 --> 0:10:27.320 where those signals were coming from. And in nineteen thirty one, 0:10:27.520 --> 0:10:30.719 after he had been scratching his head over where this 0:10:30.960 --> 0:10:35.240 source could have come from, he concluded that at least 0:10:35.240 --> 0:10:38.720 some of those signals had to be extraterrestrial in origin. 0:10:38.760 --> 0:10:42.040 They had to be coming from outside the Earth, from 0:10:42.240 --> 0:10:48.280 space itself. He didn't know where they were coming from 0:10:48.400 --> 0:10:51.040 or what was producing them, but he was sure that 0:10:51.160 --> 0:10:55.440 it wasn't coming from Earth. It was seemingly coming from 0:10:55.480 --> 0:10:59.080 the center of the Milky Way galaxy that, by the way, 0:10:59.120 --> 0:11:02.679 is the galaxy that that we're in the Milky Way. Well. 0:11:02.760 --> 0:11:06.640 Jansky published his findings in nineteen thirty two, and then 0:11:07.360 --> 0:11:08.920 he moved on to work with other stuff, with a 0:11:08.960 --> 0:11:11.880 telephone system. I mean, he wasn't an astronomer or an 0:11:11.920 --> 0:11:15.880 astrophysicist or anything like that, so he dedicated his attention elsewhere. 0:11:16.160 --> 0:11:21.040 But another American engineer named Grote Reber would build on 0:11:21.200 --> 0:11:24.040 Djanski's work, and by the way, I am certain I 0:11:24.080 --> 0:11:29.480 mispronounced his name entirely, but we're gonna soldier on. He 0:11:29.760 --> 0:11:32.199 read Janski's work and then he decided, you know what, 0:11:32.480 --> 0:11:35.320 I want to find out more about these these signals 0:11:35.320 --> 0:11:37.959 that seem to be coming from space. So he built 0:11:38.720 --> 0:11:42.360 an actual radio telescope. He set out to build a 0:11:42.480 --> 0:11:46.520 device specifically to detect these kind of signals, and so 0:11:46.600 --> 0:11:50.040 he built a bowl shaped antenna, you know, a parabolic 0:11:50.240 --> 0:11:52.960 kind of antenna in nineteen thirty seven, and it was 0:11:53.000 --> 0:11:56.960 capable of detecting radio signals from space. Now, when I 0:11:56.960 --> 0:12:00.360 say radio signals from space, I am not necessar barely 0:12:00.400 --> 0:12:05.160 talking about stuff that was purposefully or intelligently transmitted, because 0:12:05.200 --> 0:12:09.720 a lot of stuff in space generates radio waves. The Sun, 0:12:10.080 --> 0:12:13.920 for example, does it, Other stars do it. Pulsars and 0:12:14.000 --> 0:12:19.040 quasars produce radio waves. Radio astronomy gave scientists tools to 0:12:19.120 --> 0:12:22.440 detect and learn more about stuff in space than we 0:12:22.480 --> 0:12:26.080 could manage with things like optical telescopes, that is, light 0:12:26.360 --> 0:12:30.520 based telescopes. So in the decades following Reaver's work, we 0:12:30.559 --> 0:12:35.240 saw a lot of progress in astronomy thanks to radio telescopes. 0:12:36.000 --> 0:12:38.920 Now we're going to skip up to nineteen fifty seven, 0:12:39.320 --> 0:12:42.640 and that's when a telescope designed by Bernard Lovell and 0:12:42.760 --> 0:12:46.720 Charles's husband went live for the first time at Jodrell 0:12:46.840 --> 0:12:49.440 Bank at the University of Manchester and it was called 0:12:49.480 --> 0:12:52.719 the Mark one Telescope, though these days folks tend to 0:12:52.760 --> 0:12:56.840 refer to it as the Level telescope. And this thing's big. 0:12:57.360 --> 0:13:00.360 It has a parabolic dish to help focus radio waves 0:13:00.480 --> 0:13:04.560 on the antenna and that dish measures seventy six meters 0:13:04.640 --> 0:13:09.400 or two hundred and fifty feet across. A complicated analog 0:13:09.520 --> 0:13:13.480 computer consisting of electro mechanical components was designed so that 0:13:13.640 --> 0:13:17.000 it could position this antenna. It could point it at 0:13:17.040 --> 0:13:20.559 different sections of the sky, and this antenna could actually 0:13:20.640 --> 0:13:23.720 track a radio source as it moved across the sky, 0:13:23.840 --> 0:13:26.880 so you could point it at something and then use 0:13:26.920 --> 0:13:32.760 the computer to constantly adjust the radio antenna's position so 0:13:32.800 --> 0:13:37.040 that it moved along with this whatever the source was 0:13:37.360 --> 0:13:39.280 of the radio waves and you could get a better 0:13:39.480 --> 0:13:42.760 read on it. There's a really impressive piece of technology. 0:13:43.600 --> 0:13:45.719 And it also picked up the third stage of the 0:13:45.840 --> 0:13:49.000 rocket that was used to launch Sputnik. That's the first 0:13:49.000 --> 0:13:52.320 man made satellite. That's the one the Soviet Union put 0:13:52.400 --> 0:13:55.960 up into space, and it was launched just a few 0:13:56.000 --> 0:13:59.400 months after the Level Telescope came online, so it actually 0:13:59.480 --> 0:14:02.120 detected that that was one of the things that indicated 0:14:02.120 --> 0:14:06.440 how useful and important radio telescopes could be beyond just 0:14:06.720 --> 0:14:11.199 their astronomical or cosmological uses. Now, the power of the 0:14:11.280 --> 0:14:15.720 level telescope impressed a lot of very smart people, and 0:14:15.800 --> 0:14:19.880 a couple of those people were Giuseppe Cocconi and Philip Morrison. 0:14:20.720 --> 0:14:25.440 They proposed that a sufficiently powerful transmitter and a sufficiently 0:14:25.520 --> 0:14:30.440 powerful receiver would be able to send communications across vast 0:14:30.480 --> 0:14:34.400 reaches of space. So if you had parabolic antennas of 0:14:34.520 --> 0:14:39.320 particularly strong power in two different locations, you could transmit 0:14:39.400 --> 0:14:43.720 and receive radio signals even if you were light years 0:14:43.760 --> 0:14:47.080 apart from each other. Now, that communication is still restricted 0:14:47.120 --> 0:14:49.640 by the speed of light, because radio waves travel at 0:14:49.680 --> 0:14:52.200 the speed of light, and nothing goes faster than the 0:14:52.240 --> 0:14:54.920 speed of light. So if the two points of contact 0:14:54.920 --> 0:14:57.920 are let's say, eight light years apart from each other, 0:14:58.200 --> 0:15:01.000 it would take eight years for an out going message 0:15:01.120 --> 0:15:04.320 to reach the recipient and another eight years to wait 0:15:04.360 --> 0:15:08.960 for a response, so there will be no instant messaging. 0:15:09.280 --> 0:15:11.960 But beyond that, it meant that you could take a 0:15:12.080 --> 0:15:14.920 radio telescope and you could use it to search for 0:15:15.080 --> 0:15:18.520 signs that maybe someone out there in space has already 0:15:18.560 --> 0:15:22.400 been using radio technology for communications or for other purposes, 0:15:22.760 --> 0:15:25.520 and that perhaps this could help us determine if there 0:15:25.520 --> 0:15:29.600 are other examples of intelligent life out there. I'll explain 0:15:29.680 --> 0:15:33.000 more about how this was used in just a moment, 0:15:33.040 --> 0:15:44.640 but first let's take a quick break. Kochoni and Morrison 0:15:44.800 --> 0:15:50.400 wrote a paper about their proposal titled searching for Interstellar Communications. 0:15:50.880 --> 0:15:54.560 The journal Nature published this paper, and the two scientists 0:15:54.640 --> 0:15:59.920 addressed some pretty big questions. See now, as the late 0:16:00.640 --> 0:16:07.600 great Douglas Adams once observed, space is big, really big. 0:16:08.240 --> 0:16:11.360 And these radio telescopes are directional, so you have to 0:16:11.400 --> 0:16:15.840 pick a spot to point the telescope at. But how 0:16:15.880 --> 0:16:19.000 do you determine where you should look? How do you 0:16:19.200 --> 0:16:22.080 decide this is the point in space we're going to 0:16:22.240 --> 0:16:25.840 search right now? You might start off searching the equivalent 0:16:25.960 --> 0:16:28.320 of a ghost town, and it could be that a 0:16:28.360 --> 0:16:32.520 neighboring region of space might be absolutely teeming with life. 0:16:32.760 --> 0:16:36.200 But because of that directional telescope, you wouldn't know that 0:16:36.440 --> 0:16:40.840 you're just be getting data from a total uninhabited part 0:16:40.880 --> 0:16:43.880 of space. So the implication you get is, oh, there's 0:16:43.920 --> 0:16:47.880 nobody out there. Meanwhile, like two space doors down there's 0:16:47.880 --> 0:16:51.200 a raging party going on. It's kind of like if 0:16:51.240 --> 0:16:54.920 you were staring into a warehouse from the keyhole of 0:16:55.000 --> 0:16:57.720 a door. You would only see stuff within the view 0:16:57.800 --> 0:17:00.320 of that keyhole, but there could be a whole lot 0:17:00.440 --> 0:17:03.560 more warehouse just outside your area of view. You would 0:17:03.560 --> 0:17:07.080 have no idea if anything was actually in the warehouse 0:17:07.240 --> 0:17:09.960 or not. You would only be able to see from 0:17:09.960 --> 0:17:13.600 that narrow range of the keyhole. That was the same 0:17:13.600 --> 0:17:17.320 issue they were having with radio telescopes. Moreover, you could 0:17:17.359 --> 0:17:19.800 point the radio telescope at a place where there is 0:17:19.960 --> 0:17:24.280 intelligent life, but maybe it's at a region that's so 0:17:24.520 --> 0:17:28.240 far away from the Earth we can't detect that life. 0:17:28.280 --> 0:17:31.600 So let me put that another way. Human beings started 0:17:31.640 --> 0:17:36.359 broadcasting radio in the early nineteen hundreds, so it's really 0:17:36.359 --> 0:17:39.080 been less than one hundred and fifty years since we 0:17:39.160 --> 0:17:43.199 started using radio for communication. There are stars in the 0:17:43.240 --> 0:17:47.040 Milky Way Galaxy again, the same galaxy that our solar 0:17:47.080 --> 0:17:51.320 system is in, that are around nine hundred thousand light 0:17:51.440 --> 0:17:54.760 years away from us. That means it would take light 0:17:55.359 --> 0:17:59.360 nine hundred thousand earth years to travel from that distant 0:17:59.400 --> 0:18:03.880 star to us, So it takes nearly a million years 0:18:04.240 --> 0:18:07.199 for that information to get to us. A radio communication 0:18:07.280 --> 0:18:09.880 would require the same amount of time to get to us. 0:18:10.320 --> 0:18:14.080 That means that if intelligent alien life exists, or even 0:18:14.200 --> 0:18:18.480 existed on a planet around that distant star, that life 0:18:18.480 --> 0:18:21.239 would have had to have invented and made use of 0:18:21.320 --> 0:18:24.760 radio technology a million years ago for us to pick 0:18:24.840 --> 0:18:28.720 up those signals today. That's assuming that intelligent life would 0:18:28.720 --> 0:18:34.040 have somehow survived that million years. For us to say 0:18:34.040 --> 0:18:37.560 that intelligent life exists today, right, we wouldn't know that 0:18:37.680 --> 0:18:40.159 for sure. All we could say is there appears to 0:18:40.240 --> 0:18:44.320 have been an intelligent civilization that existed a million years ago. 0:18:45.160 --> 0:18:48.760 We aren't really sure what they're up to now, because 0:18:48.760 --> 0:18:51.040 we'd have no way of knowing. We would only know 0:18:51.680 --> 0:18:55.359 from the signals that were sent from the past. A 0:18:55.400 --> 0:18:58.720 neat thing about space too, The further you look, the 0:18:58.720 --> 0:19:02.199 more you're looking into the past, you're not seeing present 0:19:02.320 --> 0:19:05.920 situations just because of the restriction of the speed of light. 0:19:06.720 --> 0:19:11.000 So you'd only really be able to see any current 0:19:11.440 --> 0:19:18.320 alien civilization if they were relatively close to us, because 0:19:18.359 --> 0:19:21.919 otherwise you can't be certain that that civilization still exists 0:19:22.040 --> 0:19:26.760 if it's thousands of light years away. Moreover, alien civilizations 0:19:26.760 --> 0:19:29.760 would only have been able to hear us if they 0:19:29.800 --> 0:19:33.480 were around one hundred and fifty light years or closer 0:19:33.840 --> 0:19:36.320 to Earth. If they're further than one hundred and fifty 0:19:36.400 --> 0:19:40.920 light years away, then our broadcasts would not have gone 0:19:41.000 --> 0:19:44.520 far enough out to reach them. This, by the way, 0:19:44.560 --> 0:19:46.639 is why a lot of science fiction stories are really 0:19:46.840 --> 0:19:50.160 more like fantasy stories. A lot of them involve aliens 0:19:50.200 --> 0:19:53.600 finding out about Earth because they picked up a radio 0:19:53.800 --> 0:19:57.439 or television broadcast. But those broadcasts have only been around 0:19:57.480 --> 0:19:59.959 for a few decades, so that would require the alien 0:20:00.080 --> 0:20:02.680 to be relatively close to Earth in the first place 0:20:02.720 --> 0:20:05.919 to pick up those transmissions because of those limitations of 0:20:05.960 --> 0:20:08.920 the speed of light. Anyway, my point was, we might 0:20:08.960 --> 0:20:12.320 be quote unquote looking at the right spot, but the 0:20:12.400 --> 0:20:15.000 right spot might be far enough away that any radio 0:20:15.080 --> 0:20:19.000 broadcasts would still be in transit to us and wouldn't 0:20:19.040 --> 0:20:21.600 have arrived yet. It may not arrive for thousands of years. 0:20:22.000 --> 0:20:24.639 And that's just one more tiny part of why looking 0:20:24.640 --> 0:20:27.879 for meaningful signals in the sky is a huge challenge. 0:20:28.240 --> 0:20:31.280 You've heard the phrase looking for a needle in a haystack. Well, 0:20:31.320 --> 0:20:35.160 it's like that, but you know, roughly a bazillion times 0:20:35.280 --> 0:20:39.440 harder than that. Kachoni and Morrison set out an argument 0:20:39.560 --> 0:20:42.280 about which areas of the galaxy would be most likely 0:20:42.359 --> 0:20:46.679 to host an intelligent civilization capable of radio transmissions. This 0:20:46.800 --> 0:20:51.080 included targeting stars that are neither too hot nor too 0:20:51.119 --> 0:20:56.040 small or cold. Hot stars burn out quickly, and the 0:20:56.160 --> 0:20:59.080 thought was, if it's a really hot star, it might 0:20:59.400 --> 0:21:03.560 go through its life cycle fast enough that life doesn't 0:21:03.560 --> 0:21:06.320 have a chance to evolve on any planets that might 0:21:06.359 --> 0:21:09.760 be an orbit around that star. So the stars life 0:21:09.760 --> 0:21:13.440 cycle is literally too short for life to have formed 0:21:13.760 --> 0:21:18.600 around that system. Smaller, colder stars tend to be the 0:21:18.680 --> 0:21:21.280 really old ones, ones that have been around for billions 0:21:21.320 --> 0:21:25.760 of years, and with that much time, eventually, orbiting planets 0:21:25.800 --> 0:21:29.159 will lock on a star so that one side of 0:21:29.160 --> 0:21:31.960 the planet always faces the star and the opposite side 0:21:31.960 --> 0:21:34.679 of the planet always faces away from the star. So 0:21:34.760 --> 0:21:37.439 one side is always lit and the other side is 0:21:37.480 --> 0:21:40.760 always dark, and that kind of planet would probably be 0:21:40.880 --> 0:21:46.280 incapable of supporting life. So, said Cochoni and Morrison, we 0:21:46.280 --> 0:21:48.960 should look for stars that are not that different from 0:21:49.119 --> 0:21:52.280 the Sun. These would be the right age and size 0:21:52.320 --> 0:21:56.200 to potentially support life if an orbiting planet were within 0:21:56.280 --> 0:21:59.000 a certain range, which we tend to refer to as 0:21:59.040 --> 0:22:02.320 the Goldilocks region. It has to be a distance that's 0:22:02.600 --> 0:22:05.240 not too close to the Sun but not too far 0:22:05.320 --> 0:22:08.760 away either, and that really narrows things down in fact, 0:22:08.880 --> 0:22:12.760 and it means we can cross off potentially thousands or 0:22:12.840 --> 0:22:17.320 millions of stars from our otherwise unmanageably huge list of 0:22:17.359 --> 0:22:20.480 potential targets to look at. And so with this in mind, 0:22:20.960 --> 0:22:25.600 another astronomer and an astrophysicist named Frank Drake decided to 0:22:25.640 --> 0:22:28.679 take this hypothesis and to actually put it in action. 0:22:29.240 --> 0:22:32.800 He conducted the first search for extraterrestrial intelligence with the 0:22:32.840 --> 0:22:36.880 help of radio astronomy, and it was called Project Ozma, 0:22:37.040 --> 0:22:42.080 named after the character Ozma from L. Frank Baum's oz books. 0:22:43.080 --> 0:22:47.040 Drake secured time on a radio telescope that measured twenty 0:22:47.080 --> 0:22:50.359 six meters or eighty five feet across to scan for 0:22:50.480 --> 0:22:55.919 radio frequencies that originated out of Tao Seti and Epsilon Eridani. 0:22:56.040 --> 0:22:59.800 Those are two different stars, and both stars are relatively 0:23:00.040 --> 0:23:02.800 close to our own solar system, and both our Sun 0:23:03.160 --> 0:23:07.440 like enough that they could serve as potentially good targets. 0:23:07.480 --> 0:23:12.879 Based on Kochoni and Morrison's proposed guidelines. Apart from one outlier, 0:23:13.600 --> 0:23:17.440 his team found no evidence of radio signals indicating potential 0:23:17.480 --> 0:23:21.680 intelligent communication. The one outlier they did pick up, while 0:23:21.720 --> 0:23:25.439 initially interesting, proved to be terrestrial in nature, meaning that 0:23:25.480 --> 0:23:29.880 it originated from an aircraft made by dull old humans, 0:23:29.920 --> 0:23:32.399 didn't come from outer space. It was something that we 0:23:32.520 --> 0:23:35.200 had created and this radio telescope just happened to pick 0:23:35.240 --> 0:23:39.240 it up. And that actually illustrates another challenge with using 0:23:39.400 --> 0:23:43.960 radio telescopes, weeding out the signals that are actually coming 0:23:44.080 --> 0:23:48.000 from us as opposed to coming from space. And it 0:23:48.040 --> 0:23:50.639 sure would be embarrassing to come forward with a claim 0:23:50.680 --> 0:23:53.920 that you've discovered alien communication only for it to turn 0:23:53.920 --> 0:23:56.359 out to be a terrestrial signal, like an old Mork 0:23:56.400 --> 0:24:00.240 and Mindy episode, or something that's only got a character 0:24:00.320 --> 0:24:02.159 who's supposed to be an alien in it, it's not 0:24:02.320 --> 0:24:06.760 actually alien. Now, Luckily, this early experience taught researchers to 0:24:06.800 --> 0:24:10.960 include a secondary antenna that would only be sensitive enough 0:24:11.000 --> 0:24:15.520 to detect terrestrial signals. So you put this secondary antenna 0:24:15.960 --> 0:24:18.600 near the first antenna. They're both pointed at the same 0:24:18.680 --> 0:24:23.240 section of sky, and then when you get a beep, 0:24:23.560 --> 0:24:27.200 you know you register a signal. You can compare the 0:24:27.240 --> 0:24:30.120 primary telescope, the one that you're using to search for 0:24:30.240 --> 0:24:35.840 extraterrestrial intelligence, against this smaller antenna, and if the smaller 0:24:35.840 --> 0:24:38.840 antenna also picked up the signal, you know that signal 0:24:38.920 --> 0:24:43.200 was terrestrial, because the smaller antenna isn't powerful enough to 0:24:43.240 --> 0:24:46.119 pick up stuff from outer space. So you say, all right, well, 0:24:46.160 --> 0:24:48.480 if it appears on both, we know that that came 0:24:48.520 --> 0:24:51.520 from Earth. We know that that's not actually a signal 0:24:51.560 --> 0:24:54.320 scent from somewhere out in space. So they learned that 0:24:54.400 --> 0:24:58.359 lesson very quickly, and that was very helpful. Drake further 0:24:58.440 --> 0:25:02.240 contributed to the discourse about the search for extraterrestrial intelligence 0:25:02.440 --> 0:25:05.840 by proposing a way to sort of conceptualize the possibility 0:25:06.280 --> 0:25:10.199 of detecting intelligent civilizations in the universe these days. We 0:25:10.320 --> 0:25:14.159 call it the Drake equation and it's a pretty cool concept, 0:25:14.600 --> 0:25:17.200 and it goes something like this. All right, there's a 0:25:17.280 --> 0:25:20.320 variable that we're going to call N. N represents the 0:25:20.400 --> 0:25:23.560 number of civilizations in our galaxy with which we could 0:25:23.640 --> 0:25:29.159 possibly communicate. So N is that number. It's an unknown number. 0:25:30.000 --> 0:25:32.879 What determines the value of that number, Well, it's a 0:25:32.880 --> 0:25:35.800