WEBVTT - How should we search for extra terrestrial intelligence? 0:00:00.400 --> 0:00:03.160 Hi, it's Jorge and Daniel here. And this holiday season, 0:00:03.240 --> 0:00:05.760 if you're looking for a gift for yourself, for a friend, 0:00:05.920 --> 0:00:08.320 or for your your family, why not get him the 0:00:08.360 --> 0:00:10.799 gift of Answers about the Universe. So check out our 0:00:10.840 --> 0:00:13.960 new book Frequently Ask Questions about the Universe. You can 0:00:14.000 --> 0:00:17.520 find details at universe f a q dot com. Thanks 0:00:17.520 --> 0:00:31.200 for supporting the podcast. Happy holidays everyone. How much have 0:00:31.280 --> 0:00:33.760 you thought about what it might be like to talk 0:00:33.880 --> 0:00:38.000 to aliens? While biologists wonder about what form alien life 0:00:38.040 --> 0:00:42.320 might take, linguists speculate about how we might communicate with them, 0:00:42.360 --> 0:00:46.280 and conspiracy theorists wonder whether aliens have already visited Earth 0:00:46.280 --> 0:00:50.160 and taken over our government. Physicists have long expressed confidence 0:00:50.400 --> 0:00:53.840 that they could most easily find common ground with aliens, 0:00:53.880 --> 0:00:58.000 assuming that math and physics are universal, not specific to 0:00:58.000 --> 0:01:02.680 Earth biology. Even more than that, physicists practically salivate at 0:01:02.680 --> 0:01:06.200 the prospect of learning from aliens answers to big questions 0:01:06.240 --> 0:01:08.840 in physics, how to bend space and time, or crack 0:01:08.880 --> 0:01:12.120 open black holes and play elaborate pranks on Navy pilots. 0:01:12.360 --> 0:01:14.480 But what would it actually be like to try to 0:01:14.600 --> 0:01:18.000 learn physics from aliens. Could we even understand the cosmic 0:01:18.080 --> 0:01:20.440 secrets they might share with us? Would they be so 0:01:20.520 --> 0:01:23.600 advanced it would be like Schrodinger explaining quantum mechanics to 0:01:23.680 --> 0:01:26.720 its cat. Do we actually share math and physics with 0:01:26.800 --> 0:01:30.600 every intelligent civilization out there? Or would their minds be 0:01:30.680 --> 0:01:49.560 so alien it would just be impossible. Hi, I'm Daniel. 0:01:49.560 --> 0:01:52.440 I'm a particle physicist, and I can't wait to talk 0:01:52.480 --> 0:01:55.080 to the aliens and learn the secrets of the universe. 0:01:55.280 --> 0:01:58.480 There are so many things we don't understand about the universe, 0:01:58.800 --> 0:02:01.520 and if aliens visit it or managed to send us 0:02:01.520 --> 0:02:04.400 a message, it seems likely that they might have been 0:02:04.440 --> 0:02:07.640 working on these questions for thousands or millions, or even 0:02:07.680 --> 0:02:12.320 billions of years. Imagine catapulting our understanding that far forward. 0:02:12.760 --> 0:02:15.400 We might learn about how quantum mechanics really works, or 0:02:15.440 --> 0:02:18.680 what's inside a black hole, or how the universe actually began. 0:02:19.120 --> 0:02:22.280 But is that making a basic mistake? Assuming the humans 0:02:22.280 --> 0:02:24.880 and aliens might think about science in the same way, 0:02:25.000 --> 0:02:28.440 how could we possibly anticipate what aliens might know, or 0:02:28.520 --> 0:02:31.960 think about or wonder at so Welcome to the podcast. 0:02:32.120 --> 0:02:34.959 Daniel and Jorge explain the universe of production of I 0:02:35.120 --> 0:02:37.959 Heart Media, in which we dive deep into all these 0:02:38.040 --> 0:02:40.919 questions about the universe. We asked the biggest, the deepest, 0:02:40.960 --> 0:02:44.640 the craziest questions, and we strain for answers, explaining to 0:02:44.639 --> 0:02:47.880 you everything we understand and everything that we don't. My 0:02:48.080 --> 0:02:50.440 friend and co host Jorge is on a break, but 0:02:50.520 --> 0:02:52.960 I have a special treat for you today. We are 0:02:53.080 --> 0:02:54.960 very lucky to have as a guest one of the 0:02:55.040 --> 0:02:59.480 leading scholars in the field of the search for extraterrestrial intelligence. 0:02:59.760 --> 0:03:04.120 Today we'll be talking to Jill Tarter, astronomer and longtime 0:03:04.200 --> 0:03:08.240 chair of the SETI program, the Search for Extra Terrestrial Intelligence, 0:03:08.720 --> 0:03:11.040 and so today on the program, we'll be asking the 0:03:11.160 --> 0:03:19.919 question how should we be searching for extra terrestrial life? 0:03:20.000 --> 0:03:22.760 So it's my great pleasure to introduce Dr Jill Tarter. 0:03:23.200 --> 0:03:25.639 She's very well known for leading the SETI program for 0:03:25.680 --> 0:03:28.560 many years and is also famous for introducing the phrase 0:03:28.639 --> 0:03:31.799 brown dwarf in her pH d thesis, which she completed 0:03:31.840 --> 0:03:35.400 at Berkeley nine. But she's also been a leading voice 0:03:35.440 --> 0:03:37.840 in the search for extra terrestrial life and intelligence for 0:03:37.920 --> 0:03:40.480 more than three decades and has won many awards, including 0:03:40.480 --> 0:03:43.960 the Carl Sagan Prize for Science popularization and being elected 0:03:43.960 --> 0:03:47.200 to the American Academy of Arts and Sciences. Dr Tarter, 0:03:47.360 --> 0:03:49.880 Welcome to the podcast. Thank you for joining us, Thank 0:03:49.920 --> 0:03:51.960 you for having me. Daniel. So, I actually dug into 0:03:52.000 --> 0:03:53.320 your thesis a little bit and I thought it was 0:03:53.400 --> 0:03:58.440 quite fascinating. But it's well. I actually also got my 0:03:58.520 --> 0:04:01.920 PhD from Berkeley the several years later, and I was 0:04:01.960 --> 0:04:04.560 curious reading through it. It's not obvious the direction of 0:04:04.600 --> 0:04:07.120 your career would take. So how did you get into 0:04:07.240 --> 0:04:09.920 the search for extraterrestrial intelligence? Like what set you on 0:04:10.040 --> 0:04:12.800 that course? Well, it all had to do with Berkeley 0:04:12.840 --> 0:04:16.000 and graduate school and it was a big accident. So 0:04:16.160 --> 0:04:19.599 my first year at Berkeley, I was supported on our 0:04:19.600 --> 0:04:25.120 research assistant ship to program the first computer that we 0:04:25.240 --> 0:04:28.320 ever had on our desktop. So it was a PDP 0:04:28.600 --> 0:04:32.520 eight slash s now took two people to get it 0:04:32.560 --> 0:04:36.200 on the desktop, so it wasn't that small. But the 0:04:36.240 --> 0:04:38.960 other thing about it was that it had no language, 0:04:39.600 --> 0:04:41.840 so you had to program the whole thing in often 0:04:42.400 --> 0:04:44.720 for every instruction you wanted it to do, you had 0:04:44.760 --> 0:04:47.279 to set all the ones in zeros. Kind of a 0:04:47.320 --> 0:04:50.080 pretty arcane skill, but I found it interesting and fun, 0:04:51.200 --> 0:04:53.640 so I did that for a year, and then I 0:04:53.720 --> 0:04:59.000 went on to other things. Finally, many years later, when 0:04:59.040 --> 0:05:02.039 I was about to finish my PhD and go off 0:05:02.080 --> 0:05:05.160 to a post dog, Stu Bowyer, an X ray astronomer, 0:05:05.400 --> 0:05:08.520 had a really clever idea. He'd been reading the material 0:05:08.720 --> 0:05:11.560 that had been put out by NASA aims on the 0:05:11.680 --> 0:05:14.600 search for life beyond Earth, and he said, you know, 0:05:15.200 --> 0:05:19.760 UC Berkeley has a radio telescope in northern California, and 0:05:19.800 --> 0:05:22.640 he was clever enough to know that with a radio 0:05:22.720 --> 0:05:27.479 telescope you can make essentially a noiseless copy of the 0:05:27.560 --> 0:05:32.200 voltage coming out of the telescope, and then on your 0:05:32.240 --> 0:05:35.760 copy you could process it looking for engineered signals while 0:05:35.800 --> 0:05:38.320 the astronomers went ahead and did whatever they were going 0:05:38.360 --> 0:05:43.280 to do anyway, So very clever, this idea of observing commensally. 0:05:43.760 --> 0:05:47.000 But he had no money, so he went begging for 0:05:47.120 --> 0:05:50.719 pieces of equipment, and somebody gave him a hundred channel 0:05:50.920 --> 0:05:54.440 p AR auto car. Later, and somebody else gave him 0:05:54.480 --> 0:05:58.560 this old p d P A S computer. So somebody 0:05:58.600 --> 0:06:01.720 pointed out to Stu that I used to work on 0:06:01.760 --> 0:06:04.320 that computer, and he showed up in my office one 0:06:04.360 --> 0:06:07.720 afternoon with a copy of the cyclops report that had 0:06:07.720 --> 0:06:10.880 been done at NASA, Ames saying the way to find 0:06:10.960 --> 0:06:15.760 extraterrestrial intelligence was to build an array of six hundred 0:06:15.760 --> 0:06:19.720 meter telescopes. That never happened, but anyway, he gave me 0:06:19.760 --> 0:06:22.360 that as a recruiting tool, and I read it and 0:06:22.400 --> 0:06:26.200 I just got really hooked. Here I was with potentially 0:06:27.200 --> 0:06:30.520 the right skills, in the right place, at the right 0:06:30.560 --> 0:06:34.679 time to perhaps make a contribution to answering this age 0:06:34.720 --> 0:06:39.480 old question of are we alone? So I worked with 0:06:39.720 --> 0:06:45.600 the PDP eight s again and got a program with 0:06:45.680 --> 0:06:49.440 Stu up and running at that creek, and then, you know, 0:06:50.000 --> 0:06:52.320 as I said, I was hooked, and I've stayed hooked 0:06:52.320 --> 0:06:55.880 ever since. It amazes me how we sometimes see sciences 0:06:55.920 --> 0:06:59.120 as like linear, natural, obvious progression, but so much of 0:06:59.160 --> 0:07:01.839 it depends on random accidents. Who happens to talk to 0:07:01.880 --> 0:07:04.440 who and be inspired by what? And if you ran 0:07:04.520 --> 0:07:07.520 the Earth science a hundred times in, you know, with 0:07:07.560 --> 0:07:11.960 different initial conditions, you might get completely different trajectories of intellectually, 0:07:11.960 --> 0:07:14.680 like where we end up as a species. So you 0:07:14.720 --> 0:07:17.480 mentioned this, the device that wasn't built. What is SETI 0:07:17.560 --> 0:07:20.320 actually doing? What instruments are they using and operating and 0:07:20.400 --> 0:07:23.440 what are they actually listening for right now? Well, set 0:07:23.960 --> 0:07:28.280 the search for extraterrestrial intelligence, which is a misnomer because 0:07:28.320 --> 0:07:31.200 we don't know how to find intelligence, per say, we 0:07:31.280 --> 0:07:35.320 can't even define it um. What we're doing is trying 0:07:35.360 --> 0:07:40.800 to find evidence that somebody else is using some technology 0:07:40.880 --> 0:07:45.800 that we can discover over the vast distances between the stars. 0:07:45.880 --> 0:07:50.680 And so it started out as using radio telescopes to 0:07:50.800 --> 0:07:55.360 try and find engineered signals, and then over time we 0:07:55.600 --> 0:08:03.040 expanded it into optical searches and infrared searches, and now 0:08:03.400 --> 0:08:05.960 we are trying to do something that we've known that 0:08:06.000 --> 0:08:09.680 we should be doing for the past twenty years, but 0:08:09.840 --> 0:08:11.920 just haven't had the technology to do it, and that 0:08:12.120 --> 0:08:16.080 is to look for transient signals. And the trick there 0:08:16.440 --> 0:08:19.520 is you want to look at all the sky, all 0:08:19.680 --> 0:08:24.040 the time, and at as many frequencies as you possibly can. 0:08:24.560 --> 0:08:28.560 And so now we are finally able to build starting 0:08:28.560 --> 0:08:31.720 in the optical and then moving into the radio telescopes 0:08:31.760 --> 0:08:34.360 that look at tens of thousands of square degrees at 0:08:34.360 --> 0:08:37.160 a time, and in one case, if we can complete 0:08:37.160 --> 0:08:41.000 the instrumentation, all the sky all the time looking for 0:08:41.040 --> 0:08:46.040 these transient signals. So that's the exciting frontier for CET 0:08:46.200 --> 0:08:50.000 today to try and get this sky coverage. And the 0:08:50.080 --> 0:08:54.760 other exciting thing is to begin to look at the 0:08:54.840 --> 0:08:58.600 data in a different way. Historically, we have always looked 0:08:58.640 --> 0:09:04.040 at data and said, is there a signal of this 0:09:04.240 --> 0:09:08.640 description in the data, And we have defined the signals 0:09:08.640 --> 0:09:12.960 that we're interested in as being frequency compressed in the radio, 0:09:13.200 --> 0:09:18.280 or time compressed in the optical, or monochromatic lasers in 0:09:18.320 --> 0:09:22.760 the optical. But now we're beginning to see if we 0:09:22.760 --> 0:09:26.680 can use machine learning to help us find patterns of 0:09:26.800 --> 0:09:31.319 any kind in the data without having to pre describe 0:09:31.720 --> 0:09:36.839 what pattern we're looking for. So we're hoping that algorithms 0:09:36.840 --> 0:09:39.920 in the future will be able to look at data 0:09:40.240 --> 0:09:43.280 voltage is a function of time, intensity is a function 0:09:43.320 --> 0:09:48.560 of time and say there's information content here, or no, 0:09:48.840 --> 0:09:52.199 this is all noise. That's fascinating. If we need artificial 0:09:52.200 --> 0:09:56.760 intelligence to recognize alien intelligence, well that alien intelligence is 0:09:56.840 --> 0:10:01.360 quite likely to be artificial itself by machines, So maybe 0:10:01.360 --> 0:10:03.880 we need machines as interpreters. But still we need to 0:10:03.920 --> 0:10:07.079 somehow train that machine learning. We need to teach it 0:10:07.160 --> 0:10:09.160 the kind of things that we are looking for. We 0:10:09.200 --> 0:10:12.520 can't just we're not raising generic intelligence and say go 0:10:12.559 --> 0:10:15.240 out and find some aliens, right, doesn't there need to 0:10:15.240 --> 0:10:17.800 be some fought in advance for the kinds of things 0:10:17.800 --> 0:10:21.240 we're teaching our machine learning algorithms to find. Well, actually, 0:10:21.480 --> 0:10:24.839 the real problem is how do you get a null set? 0:10:25.600 --> 0:10:29.760 How do you give it data that you know has 0:10:29.840 --> 0:10:32.920 no information content. You know, when you have a data 0:10:32.960 --> 0:10:35.920 set and we've explored it for X, Y and Z, 0:10:36.200 --> 0:10:40.360 it doesn't mean that Q isn't there. So generally to 0:10:40.480 --> 0:10:44.200 get a null set you generated randomly on a computer, 0:10:44.480 --> 0:10:47.240 and then you can give it lots of examples of 0:10:47.400 --> 0:10:51.040 different signals that we have detected or that we generate 0:10:51.080 --> 0:10:55.679 ourselves as the counter. And again it's early days. We're 0:10:55.840 --> 0:10:58.680 very hopeful and we'll see what happens. Right. I suppose 0:10:58.760 --> 0:11:01.280 you can't just take the ABC from the sky and 0:11:01.360 --> 0:11:03.839 say assume there's nothing here, because the whole point is 0:11:03.880 --> 0:11:06.160 to look for data in the sky, so then it 0:11:06.200 --> 0:11:09.640 would learn to ignore signalities there. So you mentioned something fascinating, 0:11:09.679 --> 0:11:12.040 which is thinking about the messages that we would send 0:11:12.160 --> 0:11:14.400 or the ones that we have sent, and know that 0:11:14.480 --> 0:11:17.720 in the early days of space exploration, you know, for example, 0:11:17.720 --> 0:11:19.959 there's a Golden Record. We put on some of our probes, 0:11:20.000 --> 0:11:22.840 and there's a message we sent out via a Recibo. 0:11:23.400 --> 0:11:25.320 How do you look at those messages that we've sent 0:11:25.520 --> 0:11:28.120 sort of with modern eyes, How would you design a 0:11:28.160 --> 0:11:31.880 message to generic aliens now you hope would be observable 0:11:31.880 --> 0:11:35.400 and detectable to the broadest set of intelligence. Well, I 0:11:35.480 --> 0:11:38.960 do something that we haven't done with the Acibo message 0:11:39.200 --> 0:11:42.120 or any of the other messages that we've transmitted, and 0:11:42.160 --> 0:11:45.040 that is I would do it for ten thousand years, 0:11:45.200 --> 0:11:50.559 all right. If you send a finite transmission, then that 0:11:51.200 --> 0:11:53.840 message is going to go past your target in a 0:11:53.920 --> 0:11:58.440 finite amount of time, and the receivers would have to 0:11:58.480 --> 0:12:01.320 be looking at you at just the right time, in 0:12:01.480 --> 0:12:04.840 just the right way as your message flies past in 0:12:04.960 --> 0:12:07.439 order to detect it. And the probability of that is 0:12:07.480 --> 0:12:10.920 pretty small. So I think what you want to do 0:12:11.200 --> 0:12:14.720 is start transmitting and then don't stop right so that 0:12:14.840 --> 0:12:19.400 whenever an emerging technology wakes up and begins to explore 0:12:19.520 --> 0:12:22.880 its environment, your signal will be there for them to 0:12:22.960 --> 0:12:27.120 find when and if they develop the right technologies and 0:12:27.360 --> 0:12:31.120 the right strategy and are motivated to be looking. So 0:12:31.880 --> 0:12:36.120 that's I think what I would do. And the reason 0:12:36.200 --> 0:12:40.439 that I'm not at all enamored of efforts to transmit 0:12:40.520 --> 0:12:43.480 messages today because we're just not grown up enough to 0:12:43.559 --> 0:12:47.000 be able to culturally be able to manage such a 0:12:47.040 --> 0:12:49.880 long term project. It's like just shouting once in the 0:12:50.000 --> 0:12:52.720 night and hoping that somebody hears. You know, it's fascinating 0:12:52.760 --> 0:12:55.319 as our message sort of sweeps across the universe. It's 0:12:55.360 --> 0:12:59.280 always somewhere, but the chances that it happens to arrive 0:12:59.480 --> 0:13:02.520 when some he's listening do seem pretty small. Do you 0:13:02.520 --> 0:13:05.000 think that's something our civilization would ever be capable of 0:13:05.200 --> 0:13:08.280 sending messages for tens of thousands of years? Do you 0:13:08.280 --> 0:13:10.280 think our civilization will last long enough to be able 0:13:10.280 --> 0:13:12.800 to do that? I hope so. And in fact, one 0:13:12.840 --> 0:13:15.920 of the things that I think about is that suppose 0:13:16.679 --> 0:13:22.840 the distribution of lifetimes of technological civilizations or technologies, because 0:13:22.880 --> 0:13:26.160 that's what we're going to find is the technology is bimodal, 0:13:27.160 --> 0:13:32.559 So you have lots of short lived technologies. They emerge, 0:13:32.920 --> 0:13:35.920 develop an either turn themselves off or do themselves in. 0:13:36.000 --> 0:13:39.440 They don't have a very long lifetime when compared to 0:13:39.480 --> 0:13:42.280 the ten billion year history of the Milky Way, galaxy. 0:13:42.600 --> 0:13:46.920 But now there might be an addition, some very long 0:13:47.040 --> 0:13:54.160 lived civilizations, And it might be that the probability of 0:13:54.280 --> 0:14:00.160 transitioning from short lived technology to a long lived technology 0:14:00.480 --> 0:14:07.600 is dependent on discovering other technological civilizations that have made 0:14:07.600 --> 0:14:11.960 it to an old age. And I think that's one 0:14:12.000 --> 0:14:16.160 of the things that today motivates me to continue working 0:14:16.200 --> 0:14:20.320 on this project. How can we have a long future 0:14:20.800 --> 0:14:24.200 for life on this planet? And if so, how and 0:14:24.240 --> 0:14:26.600 that the answer to me is if anybody else has 0:14:26.640 --> 0:14:29.480 made it through, that means we can figure it out too. 0:14:29.600 --> 0:14:33.960 Are you suggesting that discovering a longstanding alien civilization might 0:14:34.040 --> 0:14:37.480 help us build a civilization that's long standing just knowing 0:14:37.560 --> 0:14:42.400 that it's possible. I think that's not unlikely or not impossible. 0:14:42.720 --> 0:14:45.240 If I know that there's a solution to a problem, 0:14:45.360 --> 0:14:48.200 even if I can't figure it out right now, I 0:14:48.280 --> 0:14:52.760 have more motivation to figure out the solution. I know 0:14:52.880 --> 0:14:55.560 it's possible, So how the heck am I going to 0:14:55.640 --> 0:14:58.640 solve it? That's very insporational. I hope that's true. In 0:14:58.680 --> 0:15:02.600 all of these searches were looking for signals, signals generated 0:15:02.600 --> 0:15:05.960 by technologies which in the end are somewhat similar to ours. 0:15:06.400 --> 0:15:09.240 And there seems to be an implicit assumption there that 0:15:09.680 --> 0:15:13.160 you know their information, their messages will be encoded in 0:15:13.200 --> 0:15:15.440 ways that are familiar to us, even if the actual 0:15:15.880 --> 0:15:19.120 code is alien. The fact that they are sending messages 0:15:19.160 --> 0:15:23.640 coded in electromagnetic radiation of some kind assumes that you 0:15:23.640 --> 0:15:27.800 know the civilization is mathematical or scientific. Do you think 0:15:27.840 --> 0:15:30.680 that it's possible for us to imagine aliens in a 0:15:30.720 --> 0:15:33.200 more broad sense, you know, to think about aliens that 0:15:33.320 --> 0:15:37.120 might not do math or might not have a scientific exploration, 0:15:37.760 --> 0:15:39.880 or do you think that we can only search for 0:15:40.000 --> 0:15:42.880 aliens that are sort of similar to us intellectually that 0:15:42.920 --> 0:15:45.160 we could ever communicate with them. Well, they're kind of 0:15:45.200 --> 0:15:49.960 two pieces to that question. One, we have a certain 0:15:50.000 --> 0:15:53.080 amount of technology in the twenty one century, and we 0:15:53.240 --> 0:15:57.720 understand a certain subset of physics, and those are the 0:15:57.760 --> 0:16:01.240 tools we have. We can't use tools that we don't have. 0:16:01.920 --> 0:16:05.280 We can't search for things that we don't yet understand. 0:16:05.720 --> 0:16:11.520 And in terms of another technology, we're actually trying to 0:16:11.560 --> 0:16:15.480 think more broadly than we originally did, So not just 0:16:15.880 --> 0:16:20.600 radio signals or not just optical signals, but something that 0:16:20.680 --> 0:16:25.440 we call a techno signature, something that is the result 0:16:25.880 --> 0:16:30.640 of someone doing something with technology out there. And it's 0:16:30.680 --> 0:16:35.840 particularly important to think about that now because we're moving 0:16:36.080 --> 0:16:42.320 from the generation of ten class optical instruments and a 0:16:42.480 --> 0:16:51.360 hundred elements in inferometers two thirty forty telescopes and interferometers 0:16:51.480 --> 0:16:54.400 like near Cat the square kilometer array that are going 0:16:54.480 --> 0:16:58.280 to have thousands of elements. So our ability to see 0:16:58.360 --> 0:17:03.920 things on the sky is going to improve dramatically, and 0:17:04.119 --> 0:17:08.840 we want to be thinking about, oh, what's that and 0:17:08.920 --> 0:17:15.639 how the what's that might be interpreted in terms of technology, 0:17:15.800 --> 0:17:20.119 So we're thinking about signals that are almost natural or 0:17:20.240 --> 0:17:24.600 things that are obviously engineered. And obviously engineered has been 0:17:24.640 --> 0:17:27.600 the piece that we've been doing us far. But when 0:17:27.600 --> 0:17:31.680 you begin to think about almost natural, you think about 0:17:31.720 --> 0:17:36.400 maybe a pulsar, right, which has a period it's very constant, 0:17:36.440 --> 0:17:39.600 and then it changes its period. Now we've seen that 0:17:39.720 --> 0:17:42.560 in the data because there are star quakes on these 0:17:42.600 --> 0:17:45.760 neutron stars have changed the moment of inertia and change 0:17:45.800 --> 0:17:48.360 the period of the pulse sar. But what we haven't 0:17:48.359 --> 0:17:52.160 seen is a pulsar that starts at one period, changes 0:17:52.200 --> 0:17:54.840 to a second period, and then goes back to the 0:17:54.880 --> 0:17:59.359 first period. But those could well be in our data 0:17:59.400 --> 0:18:03.400 sets as we searched the sky for pulsars, So it's 0:18:03.480 --> 0:18:06.359 almost natural, and we would catch it in a net 0:18:06.520 --> 0:18:11.359 when we're doing an astronomy survey. So another example I 0:18:11.480 --> 0:18:14.280 like to think about is transit. So we've been finding 0:18:14.320 --> 0:18:18.520 all these exoplanets because they cast a shadow on the 0:18:18.560 --> 0:18:23.600 image of the star and change the stellar luminosity as 0:18:23.800 --> 0:18:26.600 the planet transits in front of the star. Now, the 0:18:26.720 --> 0:18:31.399 i AU has declared that planets are spherical, right, and 0:18:31.480 --> 0:18:34.439 so their shadows are going to be circular. But what 0:18:34.600 --> 0:18:39.320 about some giant constructed artifact that's like a Venetian blind 0:18:40.040 --> 0:18:44.600 or a triangle. Well, in the higher order moments of 0:18:44.640 --> 0:18:48.880 the light curve at ingress and egress, you could tell 0:18:48.920 --> 0:18:52.680 the difference if you looked hard enough, between a triangular 0:18:53.119 --> 0:18:58.160 shadow and a circular shadow. So that might be an 0:18:58.320 --> 0:19:04.560 almost natural signal that would in fact ultimately lead us 0:19:04.600 --> 0:19:08.640 to technology. Wow. Fascinating. So we have a whole spectrum 0:19:08.720 --> 0:19:11.960 of things which we classify as natural because we think 0:19:12.000 --> 0:19:16.560 they're not the product of intelligent action. Things are clearly artificial, 0:19:16.680 --> 0:19:19.040 like the signal that says hello, we got your air 0:19:19.160 --> 0:19:22.560 cebra message. Here's our address, and now you're imagining things 0:19:22.560 --> 0:19:26.320 in between, which are subtle evidence of deviations from sort 0:19:26.320 --> 0:19:30.160 of natural evolution of the universe because of intelligent actions. 0:19:30.359 --> 0:19:32.359 You know, we're going to have so many new and 0:19:32.520 --> 0:19:35.639 different eyes on the cosmos that we ought to be 0:19:35.720 --> 0:19:39.359 broadening our thinking. That's fascinating and it seems like a 0:19:39.520 --> 0:19:42.320 very worthwhile It still seems to me to be indicative 0:19:42.359 --> 0:19:45.119 of sort of the way that our minds work. You know, 0:19:45.240 --> 0:19:47.600 we build things that are square, and we build things 0:19:47.600 --> 0:19:51.120 that are symmetric, and we're imagining that maybe aliens could 0:19:51.160 --> 0:19:53.080 do that as well. And I certainly take your point 0:19:53.119 --> 0:19:55.320 that we can't look for things that we don't understand, 0:19:55.359 --> 0:19:57.360 and we can't look for things that we can't imagine. 0:19:57.560 --> 0:20:00.159 Does that frustrate you that you know that might be 0:20:00.320 --> 0:20:03.600 that the spectrum of intelligence aliens out there could be 0:20:03.640 --> 0:20:05.920 so much broader than we can imagine that it might 0:20:05.960 --> 0:20:09.159 make it impossible to ever discover them. Yeah. Well, for 0:20:09.240 --> 0:20:12.399 the longest time, we said, okay, if they have some 0:20:12.440 --> 0:20:16.640 technology that we might be able to detect in some fashion, 0:20:16.800 --> 0:20:19.959 they're going to have to have math, right, can't build 0:20:20.000 --> 0:20:26.480 things without some artificial way to represent them and construct them, 0:20:26.840 --> 0:20:29.800 And so we thought, okay, so that means math is 0:20:29.840 --> 0:20:34.600 the universal language of the cosmos. And then we had 0:20:34.600 --> 0:20:37.680 some really interesting talks at the Cutty Institute by people 0:20:37.680 --> 0:20:42.400 who study the human brain, and they pointed out that, yeah, 0:20:42.800 --> 0:20:48.119 they might well have math and be representing exactly the 0:20:48.240 --> 0:20:54.560 same things that are mathematical programs do, but that our 0:20:54.720 --> 0:21:00.000 math and the way we represent things is inevitably shape 0:21:00.359 --> 0:21:04.560 by the nature and structure of our human brain. And 0:21:04.680 --> 0:21:09.000 so they might well be talking about exactly the same thing, 0:21:09.400 --> 0:21:13.480 the same mathematics, but the representation of it might be 0:21:13.640 --> 0:21:17.560 so different that we don't recognize it as such. So 0:21:17.880 --> 0:21:20.080 now that's so are right now. And if you look 0:21:20.119 --> 0:21:23.159 back at the sort of history of the development of 0:21:23.359 --> 0:21:27.000 mathematics and the philosophy of mathematics, you know there are 0:21:27.040 --> 0:21:29.520 still like big open questions about how to even build 0:21:29.520 --> 0:21:32.639 a mathematical system that's self consistent, and a lot of 0:21:32.680 --> 0:21:35.920 mathematicians practicing mathematicians sort of ignore that and say, look, 0:21:35.920 --> 0:21:37.479 we have a system that mostly works. We can get 0:21:37.520 --> 0:21:40.560 stuff done. But it tells you that if human history 0:21:40.600 --> 0:21:43.520 had gone another way, if a different philosopher had been 0:21:43.560 --> 0:21:48.080 born or been influential, we might all think very differently mathematically, 0:21:48.680 --> 0:21:52.960 And so the spectrum of like possible human explorations of 0:21:53.240 --> 0:21:56.320 you know, ways to think is so potentially broad, and 0:21:56.400 --> 0:21:59.000 it's sort of terrifying to imagine how broad it might 0:21:59.040 --> 0:22:02.480 be when you're including, yeah, well there are anthropologists who 0:22:02.480 --> 0:22:05.760 tell us that there are some very isolated tribal groups 0:22:05.800 --> 0:22:10.480 that don't have a zero in their worldview. So you 0:22:10.560 --> 0:22:13.080 can do what you can do, and you can't do 0:22:13.160 --> 0:22:28.000 what you can't yet do. So you've been working on 0:22:28.000 --> 0:22:30.280 this for a while. How long do you expect that 0:22:30.359 --> 0:22:33.280 this project might take? I mean when LEGO turned on, 0:22:33.400 --> 0:22:36.480 for example, I remember thinking, well, they have no idea 0:22:36.520 --> 0:22:39.080 how common gravitational waves are, and they had no clue 0:22:39.119 --> 0:22:41.680 whether they would wait decades for the first signal, And 0:22:41.720 --> 0:22:44.280 of course they were lucky they heard something almost immediately, 0:22:44.280 --> 0:22:46.680 and it's been a treasure trove. Do you harbor such 0:22:46.720 --> 0:22:49.879 hopes that, you know, if we expand our capabilities to 0:22:49.920 --> 0:22:52.480 listen to the sky, that we might learn something too. 0:22:53.320 --> 0:22:58.320 I don't know about soon. I think this could well 0:22:58.400 --> 0:23:02.000 be a multi generation all exploration. And the reason I 0:23:02.119 --> 0:23:05.720 say that is that the volume that might need to 0:23:05.760 --> 0:23:10.000 be searched, even if an electromagnetic signal is the right 0:23:10.040 --> 0:23:13.719 thing to be looking for. That volume is really vast, 0:23:14.760 --> 0:23:20.240 and so when c turned fifty, I tried to do 0:23:21.040 --> 0:23:25.680 calculation that would show how vast it was and how 0:23:25.760 --> 0:23:29.639 much we had searched to date for an electromagnetic signal. Again, 0:23:29.800 --> 0:23:32.600 assuming that's the right thing to be looking for, there 0:23:32.600 --> 0:23:36.480 are nine different parameters that you have to explore space 0:23:36.560 --> 0:23:41.239 and time and polarization and modulation and intensity, all of us. 0:23:41.480 --> 0:23:45.280 And so I tried to make a guess at what 0:23:45.480 --> 0:23:49.040 the range of each of those parameters might be, and 0:23:49.080 --> 0:23:52.000 then I multiplied them all together some sort of a 0:23:52.080 --> 0:23:56.280 nine dimensional volume. And I'm not any good at visualizing 0:23:56.359 --> 0:23:59.320 nine dimensional volumes. So I said, okay, here's the analogy 0:24:00.280 --> 0:24:03.479 that volume. I'm going to set it equal to the 0:24:03.560 --> 0:24:07.680 volume of all the Earth's oceans and then ask how 0:24:07.800 --> 0:24:13.320 much of the Earth's oceans have we searched in fifty years. 0:24:14.240 --> 0:24:16.639 And at that time the answer was one glass of 0:24:16.640 --> 0:24:20.040 water out of the ocean. Right. That shows you how 0:24:20.160 --> 0:24:24.280 vast the search might need to be. And then when 0:24:24.400 --> 0:24:28.040 city turned sixty, ten years later, the students at Penn State, 0:24:28.640 --> 0:24:31.880 we did the calculation and they said, it's not a glass, 0:24:31.920 --> 0:24:36.439 it's more like a small swimming pool, so that was 0:24:36.480 --> 0:24:39.040 a big improvement over ten years, but still not a 0:24:39.080 --> 0:24:44.160 lot of the oceans. So I think that it might 0:24:44.960 --> 0:24:50.040 be multi generational, either because we haven't yet invented the 0:24:50.119 --> 0:24:54.679 right technology, we don't understand the physics that's involved, or 0:24:54.960 --> 0:24:57.720 simply because the search is so vast it's going to 0:24:57.800 --> 0:25:02.320 take a while. It's getting faster all the time, primarily 0:25:02.400 --> 0:25:07.480 because of Moore's law and the improvements in our computational capabilities, 0:25:08.320 --> 0:25:10.760 but it may have to go on for a while. 0:25:11.080 --> 0:25:13.320 The exciting thing for me about research like that is 0:25:13.359 --> 0:25:15.760 that you just don't know until you begin if you're 0:25:15.760 --> 0:25:18.320 searching for a signal which is obvious or really subtle. 0:25:18.400 --> 0:25:20.680