WEBVTT - Seti Not at Home 0:00:04.400 --> 0:00:07.800 Welcome to Tech Stuff, a production from I Heart Radio. 0:00:12.119 --> 0:00:14.640 Hey there, and welcome to tech Stuff. I'm your host, 0:00:14.760 --> 0:00:18.120 Jonathan Strickland. I'm an executive producer with I Heart Radio 0:00:18.239 --> 0:00:22.320 and I love all things tech. And as I record this, 0:00:22.480 --> 0:00:26.480 it is early March twenty twenty, just days after I 0:00:26.520 --> 0:00:32.520 received some devastating news. Technically, the whole world received this news. 0:00:32.600 --> 0:00:35.320 I'm just taking it particularly hard. I heard that the 0:00:35.440 --> 0:00:40.559 distributed computing project SETI at Home is shutting down, at 0:00:40.640 --> 0:00:43.720 least for a while. It's going on hiatus by the 0:00:43.880 --> 0:00:48.639 end of March. Now, for two decades, this project has 0:00:48.680 --> 0:00:53.360 been relying on computer processing cycles provided by people like 0:00:53.400 --> 0:00:56.400 all of you guys out there, just using regular computer 0:00:56.480 --> 0:01:01.440 processors rather than some sort of massive super computer. Why 0:01:01.680 --> 0:01:04.160 was it making use of that, Well, it was combing 0:01:04.200 --> 0:01:08.200 through massive amounts of information gathered by radio telescopes in 0:01:08.240 --> 0:01:14.320 search for signals created not through some natural cosmological process, 0:01:14.360 --> 0:01:20.360 but rather as evidence of intelligent communication. SETTI, you see, 0:01:20.680 --> 0:01:25.400 stands for the search for extra terrestrial intelligence. Now, in 0:01:25.400 --> 0:01:27.920 this episode, I'm going to talk about the history of 0:01:28.040 --> 0:01:31.720 SETTI as a science, and then as well, I'm gonna 0:01:31.720 --> 0:01:33.600 I'm gonna kind of pivot around and talk about the 0:01:33.600 --> 0:01:38.440 distributed computer programs and the CETI at Home program in particular. 0:01:38.800 --> 0:01:41.800 We'll find out how distributed computing works. We'll talk about 0:01:41.800 --> 0:01:44.280 a couple of other distributed computing programs that you can 0:01:44.319 --> 0:01:47.120 still participate in if you're so inclined, and we'll also 0:01:47.240 --> 0:01:50.720 look into what's next for SETI at Home and learn 0:01:50.760 --> 0:01:53.680 why it's going on hiatus in the first place. Now, 0:01:54.440 --> 0:01:59.000 we human beings have hypothesized about the possibility of extra 0:01:59.080 --> 0:02:03.960 terrestrial or alien intelligence for a really long time. It's 0:02:03.960 --> 0:02:08.240 a frequent topic in pop culture. But perhaps I shouldn't 0:02:08.280 --> 0:02:11.880 even use the word hypothesize, because for a really long 0:02:11.919 --> 0:02:14.720 time in our history, there really wasn't any way to 0:02:14.840 --> 0:02:17.880 test that hypothesis other than for us to, you know, 0:02:18.120 --> 0:02:21.240 look up at the sky and say, Nope, that ain't it. 0:02:22.080 --> 0:02:24.800 But that would all change with the invention of the 0:02:24.919 --> 0:02:29.560 radio telescope. So it was in the nineteen twenties when 0:02:29.560 --> 0:02:34.280 an engineer named Carl Jansky, working for Bell Telephone Laboratories 0:02:34.639 --> 0:02:38.680 set the stage for radio astronomy. But that wasn't Jansky's 0:02:38.720 --> 0:02:41.920 goal at the time. He had been tasked with figuring 0:02:41.919 --> 0:02:45.680 out where the source was of some signal interference that 0:02:45.720 --> 0:02:49.840 was affecting telephone communications at that time. So in an 0:02:49.840 --> 0:02:52.880 effort to kind of figure this out, he built a 0:02:52.880 --> 0:02:56.840 directional antenna, and I guess that itself deserves its own 0:02:57.000 --> 0:03:02.200 quick explanation. So and enna's can transmitted pickup signals, right, 0:03:02.240 --> 0:03:05.080 I mean, that's what they do, and it actually helps 0:03:05.120 --> 0:03:10.359 to talk about transmitters first to understand how receiving antenna works. 0:03:10.840 --> 0:03:15.239 So a transmitter takes an electrical signal, typically one that's 0:03:15.280 --> 0:03:19.880 been boosted with amplification, and sends that signal to a 0:03:19.960 --> 0:03:25.480 transmitting antenna. Now we know that electricity and magnetism are related, right, 0:03:25.600 --> 0:03:29.160 We've talked about that a ton in previous episodes, and 0:03:29.200 --> 0:03:32.720 we've talked about electro magnetism and the electro magnetic spectrum 0:03:32.760 --> 0:03:36.640 a lot on this show, even recently. So if you 0:03:36.720 --> 0:03:41.160 run a current through a conductor, it generates electromagnetic waves, 0:03:41.280 --> 0:03:45.600 including if the conductor's big enough, radio waves. Now on 0:03:45.640 --> 0:03:50.400 the electromagnetic spectrum, radio waves have the longest wavelengths if 0:03:50.440 --> 0:03:53.760 you look across that spectrum. They are a non ionizing 0:03:53.840 --> 0:03:56.720 form of radiation, meaning they lack the power to strip 0:03:56.760 --> 0:04:00.800 electrons away from atoms, and they aren't harmful. The waste 0:04:00.800 --> 0:04:03.400 stuff like X rays or gamma rays are. So you 0:04:03.440 --> 0:04:06.800 can wander around and you know, I have radio waves 0:04:06.880 --> 0:04:08.960 hitting you. It's not gonna affect you in any way. 0:04:09.280 --> 0:04:13.640 You won't even notice. Okay, So sending a powerful electrical 0:04:13.680 --> 0:04:19.120 current through a big conductor generates radio waves along with 0:04:19.160 --> 0:04:24.919 other electromagnetic radiation. You can encode information on radio waves 0:04:25.240 --> 0:04:29.440 by altering that signal in some way. Otherwise you're just 0:04:29.560 --> 0:04:32.679 sending out a long, steady tone like a sign wave. 0:04:33.279 --> 0:04:37.159 The two main ways to do this are frequency modulation, 0:04:37.320 --> 0:04:40.039 in which you change the frequency of the radio waves 0:04:40.080 --> 0:04:42.920 that you're sending out within a certain band of frequencies, 0:04:43.360 --> 0:04:46.840 or amplitude modulation, in which you change the amplitude. Or 0:04:46.960 --> 0:04:48.839 you can think of it as almost like the strength 0:04:49.080 --> 0:04:52.000 of the radio waves that you're sending out. That would 0:04:52.800 --> 0:04:56.480 end up being FM and a M radio respectively. All right, 0:04:56.560 --> 0:05:00.560 So receivers take that same process, but they reverse it. 0:05:01.240 --> 0:05:04.440 So as long as the signals that the antenna pick 0:05:04.480 --> 0:05:07.800 up are fluctuating in some way, then it's going to 0:05:08.120 --> 0:05:11.840 create an electric current in that antenna. So a properly 0:05:12.000 --> 0:05:17.159 tuned receiver that encounters the respect of radio wave radiation. 0:05:17.720 --> 0:05:20.520 We'll see that whole process go and reverse. The radio 0:05:20.520 --> 0:05:23.960 waves will induce electricity to flow through the antenna to 0:05:24.080 --> 0:05:26.200 whatever device the antenna is hooked up to. It might 0:05:26.240 --> 0:05:28.360 be a meter, in which case you'll see the little 0:05:28.360 --> 0:05:32.120 indicator show that there's a current running through that circuit. 0:05:33.400 --> 0:05:36.680 Or it'll my radio so that you can listen to 0:05:36.720 --> 0:05:39.799 a radio station that way, could be any number of things. 0:05:40.400 --> 0:05:43.680 It usually will require amplification of that signal. Typically the 0:05:43.680 --> 0:05:48.000 signal is too weak to actually power anything significant, so 0:05:48.120 --> 0:05:50.400 you would run it through an amplifier and thus take 0:05:50.440 --> 0:05:53.520 that same signal and just boost its power before sending 0:05:53.520 --> 0:05:55.320 it on to do whatever it was supposed to do. 0:05:55.760 --> 0:06:00.799 Now I've dramatically simplified this whole process. There's other stuff 0:06:00.839 --> 0:06:03.680 we could talk about that really plays an important part, 0:06:03.800 --> 0:06:07.800 like the concept of resonance, but that is really the 0:06:07.839 --> 0:06:10.920 matter for a different episode entirely, and I have covered 0:06:10.960 --> 0:06:16.000 it in previous episodes too. So essentially that's how antenna's work. 0:06:16.160 --> 0:06:20.000 So jen Ski designed a directional antenna as opposed to 0:06:20.080 --> 0:06:24.560 an omnidirectional antenna. So an omnidirectional antenna, as the name implies, 0:06:24.600 --> 0:06:28.359 can pick up signals transmitted from any direction from around 0:06:28.400 --> 0:06:31.799 that antenna. Like, just imagine an antenna poking up straight 0:06:31.839 --> 0:06:34.920 in the air and it can accept radio waves from 0:06:34.960 --> 0:06:39.520 any direction. Uh Now, a directional antenna is designed in 0:06:39.560 --> 0:06:43.200 such a way where it is much more sensitive at 0:06:43.720 --> 0:06:46.839 picking up signals that are coming from specific points. You 0:06:46.880 --> 0:06:50.160 have to point the antenna toward the area where you 0:06:50.360 --> 0:06:54.040 expect there to be a radio wave, and the benefit 0:06:54.160 --> 0:06:57.560 is you can pick up much weaker radio waves typically 0:06:57.680 --> 0:07:00.960 with a directional antenna than with an omnidirect antenna. However, 0:07:01.480 --> 0:07:04.320 if you're a couple of degrees off, if your antenna 0:07:04.440 --> 0:07:07.839 is not pointed directly at the source, you may not 0:07:07.960 --> 0:07:10.360 pick up the signal at all. So if you have 0:07:10.520 --> 0:07:14.000 the directional antenna pointed north, for example, but the source 0:07:14.040 --> 0:07:17.000 of radio waves is to the west, then your antenna 0:07:17.080 --> 0:07:19.680 might not pick it up because it's pointed in a 0:07:19.680 --> 0:07:24.480 different direction. However, this is an incredibly useful tool if 0:07:24.600 --> 0:07:29.840 you're trying to look for a specific you know, source 0:07:29.880 --> 0:07:33.440 of of interference in your telephone communication system. I should 0:07:33.440 --> 0:07:38.120 also add that there's another important thing about directional antennas 0:07:38.240 --> 0:07:41.600 is that even they have a limit to how far 0:07:41.680 --> 0:07:45.160 they can pick up a signal here on Earth. And 0:07:45.200 --> 0:07:47.760 this has to do with the fact that our Earth 0:07:48.320 --> 0:07:53.520 is and brace yourselves round, it's not a flat earth people. 0:07:54.440 --> 0:07:57.440 The way radio waves propagate and it can be transmitted 0:07:57.440 --> 0:08:01.320 and received, that alone would ls that the Earth has 0:08:01.360 --> 0:08:04.320 to be curved. And here's the reason. When you broadcast 0:08:04.400 --> 0:08:07.760 radio waves, they travel outward in a straight line from 0:08:07.800 --> 0:08:11.920 the source of radiation. And if the Earth were flat, 0:08:12.200 --> 0:08:14.560 then no matter how far away you were, if you 0:08:14.600 --> 0:08:16.960 had a sensitive enough antenna, you'd be able to pick 0:08:17.040 --> 0:08:21.200 up radio waves from that source. However, because the Earth curves, 0:08:21.880 --> 0:08:25.440 then you look at two different points on the planet 0:08:25.520 --> 0:08:28.600 that are far enough apart. That curvature means that if 0:08:28.640 --> 0:08:31.520 you're having radio waves travel out at a straight line 0:08:31.560 --> 0:08:34.600 from point A, they won't reach point B because it's 0:08:34.640 --> 0:08:38.360 curved away from the path right, it'll be those radio 0:08:38.360 --> 0:08:41.640 waves will just go out into space instead. There is 0:08:42.640 --> 0:08:45.959 an exception to this, and that's certain radio waves are 0:08:46.000 --> 0:08:49.040 the right length where they can bounce off the Earth's 0:08:49.120 --> 0:08:52.480 ion a sphere. So you can use the ionosphere sort 0:08:52.520 --> 0:08:55.880 of like a mirror. You can point radio waves toward it. 0:08:55.880 --> 0:08:59.160 It will bounce off the ionosphere and then angle back 0:08:59.320 --> 0:09:02.160 down toward the surface of the Earth. That way, you 0:09:02.160 --> 0:09:05.880 could actually transmit much further than you could just from 0:09:06.000 --> 0:09:08.520 line of sight. You can think of his line of sight. 0:09:08.559 --> 0:09:10.080 You don't even actually have to be able to see 0:09:10.080 --> 0:09:12.040 the thing. It just has to be, like I said, 0:09:12.080 --> 0:09:15.280 a more or less straight path from point A to 0:09:15.320 --> 0:09:17.240 point B for you to pick it up. Okay, but 0:09:17.679 --> 0:09:22.120 that's beside the point. Jansky's antenna was a directional antenna 0:09:22.600 --> 0:09:27.400 meant to pick up that source of uh of of interference. 0:09:28.960 --> 0:09:34.400 So he's picking up weird signals as he's using this 0:09:34.480 --> 0:09:38.720 directional antenna that don't seem to have any terrestrial source 0:09:38.960 --> 0:09:41.920 to them, Like if he pointed the directional antenna up 0:09:42.000 --> 0:09:44.840 into the air. He was picking up signals, but he 0:09:44.880 --> 0:09:48.240 could not identify where those signals were coming from. And 0:09:48.280 --> 0:09:52.400 in nine after he had been scratching his head over 0:09:52.480 --> 0:09:56.920 where this source could have come from, he concluded that 0:09:56.960 --> 0:09:59.520 at least some of the signals had to be extra 0:09:59.559 --> 0:10:01.920 to rest real and origin. They had to be coming 0:10:02.320 --> 0:10:07.559 from outside the Earth, from space itself. He didn't know 0:10:08.760 --> 0:10:12.280 where they were coming from or what was producing them, 0:10:12.360 --> 0:10:15.000 but he was sure that it wasn't coming from Earth. 0:10:15.520 --> 0:10:18.960 It was seemingly coming from the center of the Milky 0:10:19.000 --> 0:10:22.080 Way galaxy that, by the way, is the galaxy that 0:10:22.520 --> 0:10:26.320 that we're in the Milky Way. Well, Jansky published his 0:10:26.400 --> 0:10:30.000 findings in nineteen thirty two, and then he moved on 0:10:30.040 --> 0:10:32.160 to work with other stuff, with a telephone system. I mean, 0:10:32.200 --> 0:10:35.679 he wasn't an astronomer or an astrophysicist or anything like that, 0:10:35.760 --> 0:10:40.319 so he dedicated his attention elsewhere. But another American engineer 0:10:40.400 --> 0:10:44.720 named Grote Reber would build on Jansky's work, and by 0:10:44.720 --> 0:10:48.600 the way, I am certain I mispronounced his name entirely, 0:10:48.640 --> 0:10:53.120 but we're gonna soldier on. He read Jenski's work and 0:10:53.160 --> 0:10:55.319 then he decided, you know what, I want to find 0:10:55.320 --> 0:10:58.080 out more about these these signals that seemed to be 0:10:58.080 --> 0:11:02.720 coming from space. So he built and actual radio telescope. 0:11:03.000 --> 0:11:06.880 He set out to build a device specifically to detect 0:11:07.000 --> 0:11:09.800 these kind of signals, and so he built a bowl 0:11:10.040 --> 0:11:13.199 shaped antenna, you know, a parabolic kind of antenna in 0:11:13.320 --> 0:11:17.080 nineteen seven, and it was capable of detecting radio signals 0:11:17.080 --> 0:11:20.600 from space. Now, when I say radio signals from space, 0:11:21.120 --> 0:11:24.439 I am not necessarily talking about stuff that was purposefully 0:11:24.760 --> 0:11:29.040 or intelligently transmitted, because a lot of stuff in space 0:11:29.320 --> 0:11:34.000 generates radio waves. The Sun, for example, does it, other 0:11:34.080 --> 0:11:38.600 stars do it. Pulsars and quasars produce radio waves. Radio 0:11:38.600 --> 0:11:42.839 astronomy gave scientists tools to detect and learn more about 0:11:42.920 --> 0:11:46.120 stuff and space. Then we could manage with things like 0:11:46.240 --> 0:11:50.280 optical telescopes, that is, light based telescopes. So in the 0:11:50.320 --> 0:11:54.120 decades following Reaver's work we saw a lot of progress 0:11:54.360 --> 0:11:58.640 in astronomy thanks to radio telescopes. Now we're going to 0:11:58.760 --> 0:12:02.080 skip up to nine teen fifty seven, and that's when 0:12:02.120 --> 0:12:06.360 a telescope designed by Bernard Level and Charles Husband went 0:12:06.520 --> 0:12:09.520 live for the first time at Jodrell Bank at the 0:12:09.600 --> 0:12:13.439 University of Manchester, and it was called the Mark one telescope, 0:12:13.440 --> 0:12:15.800 though these days folks tend to refer to it as 0:12:15.880 --> 0:12:19.800 the Level telescope. And this thing is big. It has 0:12:19.840 --> 0:12:22.920 a parabolic dish to help focus radio waves on the 0:12:22.960 --> 0:12:27.120 antenna and that dish measures seventy six meters or two 0:12:27.280 --> 0:12:32.840 hundred fifty feet across. A complicated analog computer consisting of 0:12:32.840 --> 0:12:36.920 electro mechanical components was designed so that it could position 0:12:37.160 --> 0:12:41.280 this antenna, could point it at different sections of the sky, 0:12:41.360 --> 0:12:44.560 and this antenna could actually track a radio source as 0:12:44.600 --> 0:12:47.440 it moved across the sky, so you could point it 0:12:47.480 --> 0:12:51.760 at something and then use the computer to constantly adjust 0:12:52.120 --> 0:12:57.000 the radio antenna's position so that it moved along with 0:12:57.520 --> 0:13:00.560 this whatever the source was of the R waves, and 0:13:00.600 --> 0:13:02.760 you could get a better read on it. And there's 0:13:02.800 --> 0:13:06.320 a really impressive piece of technology. Uh. And it also 0:13:06.360 --> 0:13:08.880 picked up the third stage of the rocket that was 0:13:08.960 --> 0:13:12.559 used to launch spot Nick. That's the first man made satellite, 0:13:12.960 --> 0:13:15.280 that's the one the Soviet Union put up into space. 0:13:15.840 --> 0:13:18.920 And uh, it was launched just a few months after 0:13:18.960 --> 0:13:22.240 the level telescope came online, so it actually detected that. 0:13:22.240 --> 0:13:25.280 That was one of the things that indicated how useful 0:13:25.320 --> 0:13:30.640 and important radio telescopes could be beyond just their astronomical 0:13:30.720 --> 0:13:34.439 or cosmological uses. Now, the power of the level telescope 0:13:35.040 --> 0:13:38.360 impressed a lot of very smart people, and a couple 0:13:38.360 --> 0:13:43.120 of those people were Giuseppe Coccone and Philip Morrison. They 0:13:43.160 --> 0:13:48.160 proposed that a sufficiently powerful transmitter and a sufficiently powerful 0:13:48.240 --> 0:13:53.040 receiver would be able to send communications across vast reaches 0:13:53.080 --> 0:13:57.520 of space. So if you had parabolic antennas of particularly 0:13:57.679 --> 0:14:01.679 strong power in two different locations, you could transmit and 0:14:01.720 --> 0:14:05.559 receive radio signals even if you were you know, light 0:14:05.640 --> 0:14:08.720 years apart from each other. Now that communication is still 0:14:08.760 --> 0:14:11.640 restricted by the speed of light, because radio weights travel 0:14:11.679 --> 0:14:14.319 at the speed of light and nothing goes faster than 0:14:14.360 --> 0:14:16.560 the speed of light. So if the two points of 0:14:16.600 --> 0:14:20.120 contact are let's say, eight light years apart from each other, 0:14:20.360 --> 0:14:23.320 it would take eight years for an outgoing message to 0:14:23.480 --> 0:14:26.600 reach the recipient and another eight years to wait for 0:14:26.600 --> 0:14:31.120 a response. So um, there will be no instant messaging. 0:14:31.480 --> 0:14:34.120 But beyond that, it meant that you could take a 0:14:34.240 --> 0:14:37.120 radio telescope and you could use it to search for 0:14:37.240 --> 0:14:40.680 signs that maybe someone out there in space has already 0:14:40.720 --> 0:14:44.640 been using radio technology for communications or for other purposes, 0:14:44.920 --> 0:14:47.680 and that perhaps this could help us determine if there 0:14:47.720 --> 0:14:51.760 are other examples of intelligent life out there. I'll explain 0:14:51.840 --> 0:14:55.200 more about how this was used in just a moment, 0:14:55.200 --> 0:15:05.240 but first let's take a quick break. Coach Tony and 0:15:05.280 --> 0:15:09.640 Morrison wrote a paper about their proposal titled searching for 0:15:09.800 --> 0:15:14.760 Interstellar Communications. The journal Nature published this paper, and the 0:15:14.800 --> 0:15:20.640 two scientists address some pretty big questions. See now, as 0:15:20.680 --> 0:15:26.720 the late great Douglas Adams once observed, space is big, 0:15:27.520 --> 0:15:32.200 really big, and these radio telescopes are directional, so you 0:15:32.280 --> 0:15:35.640 have to pick a spot to point the telescope at. 0:15:36.680 --> 0:15:39.920 But how do you determine where you should look? How 0:15:39.960 --> 0:15:42.840 do you decide this is the point in space we're 0:15:42.880 --> 0:15:46.360 going to search right now. You might start off searching 0:15:46.360 --> 0:15:49.200 the equivalent of a ghost town, and it could be 0:15:49.280 --> 0:15:52.840 that a neighboring region of space might be absolutely teeming 0:15:53.120 --> 0:15:56.720 with life. But because of that directional telescope, you wouldn't 0:15:56.960 --> 0:16:01.760 know that. You're just be getting data from total uninhabited 0:16:01.840 --> 0:16:04.840 part of space. So the implication you get as oh, 0:16:04.840 --> 0:16:08.760 there's nobody out there. Meanwhile, like two space doors down, 0:16:08.800 --> 0:16:12.200 there's a raging party going on. It's kind of like 0:16:12.240 --> 0:16:15.920 if you were staring into a warehouse from the keyhole 0:16:16.000 --> 0:16:18.560 of a door. You would only see stuff within the 0:16:18.640 --> 0:16:21.160 view of that keyhole, but there could be a whole 0:16:21.280 --> 0:16:24.440 lot more warehouse just outside your area of view. You 0:16:24.480 --> 0:16:27.640 would have no idea if anything was actually in the 0:16:27.680 --> 0:16:30.320 warehouse or not. You would only be able to see 0:16:30.960 --> 0:16:34.520 from that narrow range of the keyhole. That was the 0:16:34.560 --> 0:16:38.200 same issue they were having with radio telescopes. Moreover, you 0:16:38.240 --> 0:16:40.720 could point the radio telescope at a place where there 0:16:40.880 --> 0:16:45.280 is intelligent life but maybe it's at a region that's 0:16:45.360 --> 0:16:49.400 so far away from the Earth we can't detect that life. 0:16:49.480 --> 0:16:52.760 So let me put that another way. Human beings started 0:16:52.800 --> 0:16:57.520 broadcasting radio in the early nineteen hundreds, so it's really 0:16:57.560 --> 0:17:00.800 been less than a hundred fifty years since we started 0:17:00.880 --> 0:17:04.760 using radio for communication. There are stars in the Milky 0:17:04.760 --> 0:17:08.600 Way Galaxy again, the same galaxy that our solar system 0:17:08.680 --> 0:17:12.919 is in, that are around nine hundred thousand light years 0:17:13.000 --> 0:17:16.840 away from us. That means it would take light nine 0:17:17.000 --> 0:17:20.840 hundred thousand earth years to travel from that distant star 0:17:21.440 --> 0:17:25.520 to us, so it takes nearly a million years for 0:17:25.560 --> 0:17:28.680 the information to get to us. A radio communication would 0:17:28.680 --> 0:17:31.040 require the same amount of time to get to us. 0:17:31.520 --> 0:17:35.320 That means that if intelligent alien life exists, or even 0:17:35.359 --> 0:17:39.680 existed on a planet around that distant star, that life 0:17:39.680 --> 0:17:42.359 would have had to have invented and made use of 0:17:42.480 --> 0:17:45.920 radio technology a million years ago for us to pick 0:17:46.000 --> 0:17:49.880 up those signals today. That's assuming that intelligent life would 0:17:49.920 --> 0:17:54.639 have somehow survived that million years. Uh for us to 0:17:54.960 --> 0:17:58.440 say that intelligent life exists today, right we we wouldn't 0:17:58.440 --> 0:18:00.800 know that for sure. All we could say is there 0:18:00.800 --> 0:18:04.399 appears to have been an intelligent civilization that existed a 0:18:04.520 --> 0:18:08.000 million years ago, we aren't really sure what they're up 0:18:08.040 --> 0:18:11.480 to now because we'd have no way of knowing. We 0:18:11.520 --> 0:18:15.040 would only know from the signals that were sent from 0:18:15.080 --> 0:18:18.320 the past. That's the neat thing about space too. The 0:18:18.440 --> 0:18:21.520 further you look, the more you're looking into the past, 0:18:22.119 --> 0:18:26.239 you're not seeing present situations just because the restriction of 0:18:26.280 --> 0:18:30.680 the speed of light. So you'd only really be able 0:18:30.760 --> 0:18:36.919 to see any current alien civilization if they were, you know, 0:18:37.160 --> 0:18:40.879 relatively close to us, because otherwise you can't be certain 0:18:40.920 --> 0:18:44.879 that that civilization still exists if it's thousands of light 0:18:44.920 --> 0:18:49.200 years away. Moreover, alien civilizations would only have been able 0:18:49.240 --> 0:18:52.639 to hear us if they were around a hundred fifty 0:18:52.760 --> 0:18:56.719 light years or closer to Earth. If they're further than 0:18:56.760 --> 0:19:01.119 a hundred fifty light years away, then our podcasts would 0:19:01.119 --> 0:19:05.199 not have gone far enough out to reach them. This, 0:19:05.280 --> 0:19:06.960 by the way, is why a lot of science fiction 0:19:07.000 --> 0:19:10.240 stories are really more like fantasy stories. A lot of 0:19:10.280 --> 0:19:13.920 them involve aliens finding out about Earth because they picked 0:19:14.000 --> 0:19:17.800 up a radio or television broadcast, but those broadcasts have 0:19:17.880 --> 0:19:20.320 only been around for a few decades, so that would 0:19:20.320 --> 0:19:23.159 require the aliens to be relatively close to Earth in 0:19:23.160 --> 0:19:26.199 the first place to pick up those transmissions because of 0:19:26.200 --> 0:19:29.600 those limitations of the speed of light. Anyway, my point 0:19:29.640 --> 0:19:33.080 was we might be quote unquote looking at the right spot, 0:19:33.280 --> 0:19:35.439 but the right spot might be far enough away that 0:19:35.520 --> 0:19:39.240 any radio broadcasts would still be in transit to us 0:19:39.680 --> 0:19:41.800 and wouldn't have arrived yet. It may not arrive for 0:19:41.880 --> 0:19:45.040 thousands of years. And that's just one more tiny part 0:19:45.080 --> 0:19:47.879 of why looking for meaningful signals in the sky is 0:19:47.920 --> 0:19:51.159 a huge challenge. You've heard the phrase looking for a 0:19:51.200 --> 0:19:53.800 needle in a haystack. Well, it's like that, but you know, 0:19:54.800 --> 0:19:59.280 roughly a bazillion times harder than that. Conconi and Morrison 0:19:59.480 --> 0:20:02.360 said out an argument about which areas of the galaxy 0:20:02.400 --> 0:20:05.960 would be most likely to host an intelligent civilization capable 0:20:06.000 --> 0:20:10.119 of radio transmissions. This included targeting stars that are neither 0:20:10.359 --> 0:20:15.760 too hot nor too small or cold. Hot stars burnout quickly, 0:20:16.240 --> 0:20:19.560 and the thought was, if it's a really hot star, 0:20:19.800 --> 0:20:23.440 it might go through its life cycle fast enough that 0:20:23.800 --> 0:20:27.080 life doesn't have a chance to evolve on any planets 0:20:27.119 --> 0:20:30.159 that might be an orbit around that star. So the 0:20:30.240 --> 0:20:33.240 star's life cycle is literally too short for life to 0:20:33.400 --> 0:20:39.159 have formed around that system, smaller, colder stars tend to 0:20:39.200 --> 0:20:41.680 be the really old ones, ones that have been around 0:20:41.720 --> 0:20:45.960 for billions of years, and with that much time, eventually, 0:20:46.040 --> 0:20:50.000 orbiting planets will lock on a star so that one 0:20:50.040 --> 0:20:52.480 side of the planet always faces the star and the 0:20:52.480 --> 0:20:55.399 opposite side of the planet always faces away from the start, 0:20:55.760 --> 0:20:58.480 So one side is always lit and the other side 0:20:58.520 --> 0:21:01.800 is always dark, and that kind of planet would probably 0:21:01.880 --> 0:21:06.720 be incapable of supporting life. So said coach Tony and Morrison, 0:21:07.359 --> 0:21:09.840 we should look for stars that are not that different 0:21:09.920 --> 0:21:12.879 from the Sun. These would be the right age and 0:21:13.040 --> 0:21:17.080 size to potentially support life if an orbiting planet were 0:21:17.119 --> 0:21:19.960 within a certain range, which we tend to refer to 0:21:20.000 --> 0:21:23.240 as the Goldilocks region. It has to be a distance 0:21:23.280 --> 0:21:26.200 that's not too close to the Sun, but not too 0:21:26.240 --> 0:21:30.000 far away either, and that really narrows things down in fact, 0:21:30.040 --> 0:21:33.960 and it means we can cross off potentially thousands or 0:21:34.040 --> 0:21:38.480 millions of stars from our otherwise unmanageably huge list of 0:21:38.520 --> 0:21:41.639 potential targets to look at. And so with this in mind, 0:21:42.119 --> 0:21:46.760 another astronomer and an astrophysicist named Frank Drake decided to 0:21:46.800 --> 0:21:49.920 take this hypothesis and to actually put it in action. 0:21:50.400 --> 0:21:54.000 He conducted the first search for extraterrestrial intelligence with the 0:21:54.040 --> 0:21:58.119 help of radio astronomy, and it was called Project OSMA, 0:21:58.240 --> 0:22:02.400 named after the care or Ozma from L. Frank Baum's 0:22:02.440 --> 0:22:07.480 oz books. Drake secured time on a radio telescope that 0:22:07.520 --> 0:22:10.960 measured twenty six ms or eighty five ft across to 0:22:11.080 --> 0:22:14.800 scan for radio frequencies that originated out of towels CT 0:22:15.440 --> 0:22:19.000 and epsilon Eri. Donnie. Those are two different stars, and 0:22:19.040 --> 0:22:22.840 both stars are relatively close to our own solar system, 0:22:23.000 --> 0:22:26.639 and both our sun like enough that they could serve 0:22:26.800 --> 0:22:31.880 as potentially good targets based on Cochoni and Morrison's proposed guidelines. 0:22:32.520 --> 0:22:36.439 Apart from one outlier, his team found no evidence of 0:22:36.520 --> 0:22:41.560 radio signals indicating potential intelligent communication. The one outlier they 0:22:41.600 --> 0:22:45.280 did pick up, while initially interesting, proved to be terrestrial 0:22:45.400 --> 0:22:49.320 in nature, meaning that it originated from an aircraft made 0:22:49.320 --> 0:22:52.760 by dull old humans, didn't come from outer space. It 0:22:52.880 --> 0:22:55.800 was something that we had created and this radio telescope 0:22:55.840 --> 0:22:58.240 just happened to pick it up. And uh. That actually 0:22:58.240 --> 0:23:02.600 illustrates another challenge with using radio telescopes, weeding out the 0:23:02.680 --> 0:23:06.639 signals that are actually coming from us as opposed to 0:23:06.760 --> 0:23:10.639 coming from space, and it sure would be embarrassing to 0:23:10.720 --> 0:23:13.840 come forward with a claim that you've discovered alien communication 0:23:14.280 --> 0:23:16.520 only for it to turn out to be a terrestrial signal, 0:23:16.720 --> 0:23:20.200 like an old Mork and Mindy episode or something that's 0:23:20.240 --> 0:23:22.600 only got a character who's supposed to be an alien 0:23:22.640 --> 0:23:26.440 and it it's not actually alien. Now, luckily, this early 0:23:26.480 --> 0:23:30.720 experience taught researchers to include a secondary antenna that would 0:23:30.800 --> 0:23:35.199 only be sensitive enough to detect terrestrial signals. So you 0:23:35.240 --> 0:23:38.920 put this secondary antenna near the first antenna. They're both 0:23:38.920 --> 0:23:42.000 pointed at the same section of sky, and then when 0:23:42.040 --> 0:23:46.120 you get a a beep, you know you register a signal. 0:23:46.600 --> 0:23:50.320 You can compare the primary telescope, the one that you're 0:23:50.400 --> 0:23:55.840 using to search for extra terrestrial intelligence, against this smaller antenna, 0:23:56.040 --> 0:23:58.800 and if the smaller antenna also picked up the signal, 0:23:59.000 --> 0:24:02.840 you know that signal was terrestrial, because the smaller intenna 0:24:03.240 --> 0:24:06.000 isn't powerful enough to pick up stuff from outer space. 0:24:06.480 --> 0:24:08.320 So you say, all right, well, if it appears on both, 0:24:08.760 --> 0:24:11.080 we know that that came from Earth. We know that 0:24:11.080 --> 0:24:14.280 that's not actually a signal scent from somewhere out in space. 0:24:14.640 --> 0:24:17.720 So they learned that lesson very quickly, and that was 0:24:17.840 --> 0:24:21.520 very helpful. Drake further contributed to the discourse about the 0:24:21.520 --> 0:24:24.960 search for extraterrestrial intelligence by proposing a way to sort 0:24:25.000 --> 0:24:30.160 of conceptualize the possibility of detecting intelligent civilizations in the universe. 0:24:30.480 --> 0:24:33.840 These days. We call it the Drake equation, and it's 0:24:33.840 --> 0:24:37.080 a pretty cool concept, and it goes something like this. 0:24:37.440 --> 0:24:39.800 All right, there's a variable that we're going to call in. 0:24:40.560 --> 0:24:44.159 In represents the number of civilizations in our galaxy with 0:24:44.200 --> 0:24:48.399 which we could possibly communicate. So in is that number. 0:24:48.640 --> 0:24:53.800 It's an unknown number. What determines the value of that number, Well, 0:24:53.800 --> 0:24:56.160 it's a bunch of stuff that you have to take 0:24:56.160 --> 0:25:00.000 into account, and that includes the average rate at which 0:25:00.119 --> 0:25:03.000 stars form in the Milky Way, the number of those 0:25:03.040 --> 0:25:06.600 stars that will actually have planets form around them, because 0:25:06.640 --> 0:25:10.320 not every star has planets, the average number of those 0:25:10.359 --> 0:25:14.920 planets that could potentially support life, the number of planets 0:25:15.119 --> 0:25:19.280