WEBVTT - Time After Time Travel 0:00:04.120 --> 0:00:07.160 Get in touch with technology with tech Stuff from how 0:00:07.200 --> 0:00:13.800 stuff works dot com. Hey there, and welcome to tech Stuff. 0:00:13.840 --> 0:00:17.200 I'm your host, Jonathan Strickland. I'm an executive producer with 0:00:17.239 --> 0:00:19.840 How Stuff Works, and iHeart radio and I love all 0:00:20.120 --> 0:00:24.119 things tech. And today we're gonna talk about a fun 0:00:24.280 --> 0:00:26.840 science fiction e kind of topic. We're gonna talk about 0:00:26.880 --> 0:00:29.280 time travel. But I don't really want to focus too 0:00:29.360 --> 0:00:35.479 much on the various proposed technological approaches to time travel, 0:00:35.520 --> 0:00:39.680 because those are all either pure science fiction or they're 0:00:40.360 --> 0:00:49.880 very much hypothetical and based upon lots of of tenuous guesswork. Instead, 0:00:49.880 --> 0:00:54.480 I'm gonna do something even more outlandish, like how could 0:00:54.480 --> 0:00:58.200 we tell if time travelers have walked among us? All Right, 0:00:58.280 --> 0:01:00.280 so we're gonna talk a little bit about that. I 0:01:00.320 --> 0:01:04.000 will cover a bit of the philosophy behind time travel, 0:01:04.640 --> 0:01:08.039 because there's still a debate about whether or not time 0:01:08.080 --> 0:01:12.559 travel is a technological possibility. I mean, we know that 0:01:12.880 --> 0:01:17.000 time travel works, because we're doing it right now, traveling 0:01:17.000 --> 0:01:20.839 forward in time at the rate of sixty minutes per hour. 0:01:21.840 --> 0:01:26.000 That that's just how time works. However, we also know 0:01:26.520 --> 0:01:29.920 that if you were able to say, get in a 0:01:29.959 --> 0:01:34.520 spaceship and push that spaceship too incredible speeds that humans 0:01:34.520 --> 0:01:36.520 have never been able to get to. But let's say 0:01:36.520 --> 0:01:38.560 that you're getting into a spaceship and you're able to 0:01:38.600 --> 0:01:44.319 accelerate to near the speed of light, like five the 0:01:44.319 --> 0:01:49.240 speed of light. That is wicked fast. And you know, 0:01:49.280 --> 0:01:51.720 we know the speed of light is the speed limit 0:01:52.120 --> 0:01:54.800 for space time in our universe, so you're not gonna 0:01:54.800 --> 0:01:57.600 go faster than that. And you can't really get mass 0:01:58.160 --> 0:02:00.160 to the speed of the speed of light as it 0:02:00.200 --> 0:02:02.440 has mass. That that's one of the limiting factors. But 0:02:02.520 --> 0:02:06.560 let's say you can get If you were able to 0:02:06.600 --> 0:02:12.000 do that, then time to you would seem to pass 0:02:12.080 --> 0:02:14.480 as normal, like a second would be a second, a 0:02:14.520 --> 0:02:16.720 minute would be a minute. It would feel exactly the 0:02:16.760 --> 0:02:20.200 same as if you were anywhere else. However, time with 0:02:20.280 --> 0:02:23.800 respect to someone who's back on Earth, it would seem 0:02:23.840 --> 0:02:26.360 to be very different. It would seem as if the 0:02:26.360 --> 0:02:28.920 people back on Earth were living out time at a 0:02:29.000 --> 0:02:33.560 much accelerated rate, and that to them, you are experiencing 0:02:33.600 --> 0:02:36.040 time at a much slower rate. So let's say you 0:02:36.080 --> 0:02:40.720 go off on a five year adventure of exploration around 0:02:40.800 --> 0:02:45.680 the galaxy. So you're zooming around at the speed of light. 0:02:46.080 --> 0:02:48.840 After five years, you come back home to Earth, it 0:02:48.840 --> 0:02:52.960 would look like everyone had aged decades while you were 0:02:52.960 --> 0:02:56.680 gone for just five years. Like you aged five years, 0:02:56.680 --> 0:03:00.840 everyone else aged fifty years. Everyone else looks much older 0:03:00.880 --> 0:03:03.800 to them. It would seem as if time had barely 0:03:03.880 --> 0:03:07.240 touched you at all. They had lived out their lives 0:03:07.600 --> 0:03:12.240 decade after decade, and you are barely any older than 0:03:12.280 --> 0:03:14.560 when you left. So, in a way, that's kind of 0:03:14.560 --> 0:03:16.600 like time travel, right it would be like you are 0:03:16.680 --> 0:03:21.160 traveling to the future, but you're doing so in a 0:03:21.200 --> 0:03:24.280 way that time is still to you, passing exactly the 0:03:24.320 --> 0:03:27.240 way it always has. It's only when you take the 0:03:27.320 --> 0:03:30.679 reference of someone else. Uh, this is why we call 0:03:30.760 --> 0:03:35.400 it special relativity. That's part of the theory of special relativity. 0:03:35.440 --> 0:03:40.560 It's relative to the perspective of someone else who's moving 0:03:40.560 --> 0:03:44.640 at a different speed throughout space time. So that kind 0:03:44.720 --> 0:03:47.400 of time travel would be totally possible if you could 0:03:47.840 --> 0:03:51.960 get a spacecraft up to those speeds, which right now 0:03:52.240 --> 0:03:55.040 would be impossible for us. But if you could, you 0:03:55.040 --> 0:03:57.080 would be able to travel to the future. But what 0:03:57.280 --> 0:04:03.000 if you wanted to travel to the asked ah That 0:04:03.040 --> 0:04:07.800 would be super duper hard traveling to the future is easy, 0:04:08.120 --> 0:04:14.120 you just wait. Traveling to the past way more tricky. So, scientifically, 0:04:14.960 --> 0:04:18.480 based upon what we understand of our universe and the 0:04:18.560 --> 0:04:22.560 laws of physics as we understand them right now, we 0:04:22.600 --> 0:04:26.960 would say that if time travel to the past is 0:04:27.040 --> 0:04:31.760 possible at all, it's probably only possible up to the 0:04:31.839 --> 0:04:35.120 point where uh are from the point where the time 0:04:35.160 --> 0:04:39.599 travel machine was first made. So, in other words, let's 0:04:39.600 --> 0:04:43.640 say it's Tuesday afternoon and you don't have anything going on, 0:04:43.960 --> 0:04:47.719 so you build yourself a time machine. Well, any point 0:04:47.839 --> 0:04:50.520 after Tuesday afternoon, you could use that time machine to 0:04:50.560 --> 0:04:53.400 travel back to Tuesday afternoon, but you couldn't go to 0:04:53.520 --> 0:04:58.840 Tuesday morning or Monday, or any point before you had 0:04:58.880 --> 0:05:01.640 created the time machine. The time machine would be your 0:05:01.680 --> 0:05:06.320 point zero. So, sadly, this would mean there's no way 0:05:06.320 --> 0:05:08.400 for us to go back to the time of the 0:05:08.440 --> 0:05:12.360 dinosaurs unless we just happened to come across some t 0:05:12.600 --> 0:05:16.359 rex's old time machine sitting around somewhere or something, or 0:05:16.440 --> 0:05:20.039 maybe an alien time machine where aliens had visited the 0:05:20.040 --> 0:05:23.800 Earth millions of years ago, and so we find their 0:05:23.839 --> 0:05:26.400 time machine. It's still miraculously works. We figured out how 0:05:26.400 --> 0:05:28.279 to use it, and it doesn't turn us into goo. 0:05:29.200 --> 0:05:33.000 That's a lot of ifs. Also, it depends upon aliens 0:05:33.000 --> 0:05:36.400 having visiting us, so a long shot at best, I 0:05:36.440 --> 0:05:40.400 guess we could say, however, we can look for evidence 0:05:40.440 --> 0:05:44.600 to see if time travelers have visited us. So let's 0:05:44.600 --> 0:05:48.240 say that someone has infened a time machine at some point. 0:05:49.240 --> 0:05:53.200 Presumably that would mean someone from the future could come 0:05:53.200 --> 0:05:57.440 back to some point in our past up to present day, 0:05:57.839 --> 0:06:00.479 any point where the time machine had been made forward, 0:06:01.040 --> 0:06:04.160 and we would potentially be able to figure that out. 0:06:05.000 --> 0:06:08.240 How would we do that? How do we identify the 0:06:08.360 --> 0:06:13.120 time travelers who secretly walk among us? Well, maybe they 0:06:13.120 --> 0:06:16.200 would identify themselves. So the first person I want to 0:06:16.200 --> 0:06:18.960 talk about is someone that I actually did a full 0:06:19.040 --> 0:06:22.560 episode of tech stuff about years and years ago. This 0:06:22.560 --> 0:06:26.039 would be John t toor or tight towards t I 0:06:26.200 --> 0:06:30.039 t O R. This is one of those Internet memes 0:06:30.080 --> 0:06:33.279 from the early early days of the Internet, back in 0:06:33.320 --> 0:06:36.600 the late nineties early two thousands, was actually a radio 0:06:37.120 --> 0:06:41.320 thing before it was an Internet thing. And the story 0:06:41.560 --> 0:06:48.560 is that, supposedly, according to the narrative, a guy living 0:06:48.760 --> 0:06:53.480 in the year twenty six travels back in time, and 0:06:53.520 --> 0:06:57.320 the purpose for traveling back in time. According to the guy, 0:06:57.520 --> 0:07:00.920 was that he needed to get a specific compute, one 0:07:00.920 --> 0:07:04.000 of the early portable computers. And by portable, I mean 0:07:04.560 --> 0:07:06.919 you could in theory lug it around, but it was 0:07:07.240 --> 0:07:09.920 super heavy, like many many, many pounds. It was a 0:07:10.000 --> 0:07:13.640 nineteen computer, the IBM fifty. I think it was like 0:07:13.760 --> 0:07:17.760 fifty pounds if I'm not mistaken in weight, not in 0:07:18.080 --> 0:07:24.040 not in cost. And that, uh, this computer somehow was 0:07:24.040 --> 0:07:27.320 going to be able to fix a problem that existed 0:07:27.440 --> 0:07:31.480 in his present day of twenty thirty six, that problem 0:07:31.520 --> 0:07:38.320 being largely this issue of a Y two K like problem. 0:07:38.440 --> 0:07:41.480 So if you remember the Y two K issue, it 0:07:41.560 --> 0:07:45.760 was that a lot of computer programming had designated years 0:07:46.000 --> 0:07:48.600 as being two digit numbers. Because this was back in 0:07:48.600 --> 0:07:52.680 the nineteen hundreds, the late nineteen hundreds, when no one 0:07:52.800 --> 0:07:55.360 was really thinking, oh, the system I build now is 0:07:55.400 --> 0:07:57.240 going to be the same one we're gonna rely on 0:07:57.560 --> 0:08:01.400 thirty years from now. So pro members were building in 0:08:01.480 --> 0:08:05.120 the shortcut of of you know, abbreviating the year to 0:08:05.200 --> 0:08:08.680 two digits. The game. By the time this is getting 0:08:08.720 --> 0:08:11.240 to the point where we're at nine, surely will have 0:08:11.320 --> 0:08:15.840 moved on to a different architecture. Software architecture, and they 0:08:15.840 --> 0:08:21.680 were wrong, because if we can build onto existing structures 0:08:21.760 --> 0:08:24.320 without having to redo the whole thing, that's usually the 0:08:24.360 --> 0:08:27.880 choice we make. So the Y two K problem was 0:08:27.920 --> 0:08:30.520 that no one was really sure what would happen when 0:08:30.640 --> 0:08:34.200 the year rolled over from to two thousand and all 0:08:34.200 --> 0:08:37.880 those two digit numbers would now say zero zero instead 0:08:37.920 --> 0:08:41.240 of nine nine. Would that mean that the systems would 0:08:41.280 --> 0:08:44.640 suddenly think that we had rolled over and now the 0:08:44.720 --> 0:08:47.600 year was nineteen hundred and a lot of those systems 0:08:48.040 --> 0:08:52.760 were important for things like calculating things like interest and uh, 0:08:52.800 --> 0:08:56.560 you know, financial issues, and other control systems. There's a 0:08:56.559 --> 0:08:59.120 worry that things were really going to go pear shaped 0:09:00.040 --> 0:09:03.400 on January one, two thousand, when all these computer systems 0:09:03.480 --> 0:09:06.440 might spontaneously fail, and so there's a huge effort made 0:09:06.840 --> 0:09:10.040 to fix that. Well, there's a similar issue in Unix, 0:09:10.360 --> 0:09:13.520 except instead of it being the year two thousand, it 0:09:13.559 --> 0:09:19.160 would be the year twenty thirty eight. And so John Titor, 0:09:19.200 --> 0:09:22.320 as he called himself, said that was why he came 0:09:22.320 --> 0:09:24.680 back in time, was to get hold of this particular 0:09:24.720 --> 0:09:27.280 computer in order to solve this problem in the future 0:09:27.440 --> 0:09:31.840 and head off a terrible calamity of all the computer 0:09:31.880 --> 0:09:36.480 systems in in the world failing in various ways. The 0:09:36.640 --> 0:09:41.640 very first appearance of this personality was in a facts 0:09:42.600 --> 0:09:44.760 that used to be a thing still is in a 0:09:44.800 --> 0:09:47.080 few rare cases, but the facts that was sent to 0:09:47.880 --> 0:09:50.640 Art Bell, who was the host of a show called 0:09:51.000 --> 0:09:54.600 Coast to Coast a m which was really a show 0:09:54.640 --> 0:09:58.160 that focused on all sorts of weird fringe theories and 0:09:58.320 --> 0:10:01.280 paranormal phenomenon and things like that. This is back in 0:10:01.400 --> 0:10:07.960 nineteen and in that message, the person claimed that the 0:10:08.120 --> 0:10:11.640 Y two K problem had created a huge catastrophe in 0:10:11.640 --> 0:10:14.520 the future. And so there were a lot of warnings 0:10:15.120 --> 0:10:18.800 that John Titor would give. Over the course of the 0:10:18.840 --> 0:10:22.480 next several years. He would show up on various message 0:10:22.480 --> 0:10:29.640 boards giving various details about the future according to his travels. 0:10:30.320 --> 0:10:35.679 You know, he's making all these these claims that were unsubstantiated, 0:10:35.720 --> 0:10:37.360 although if you wait around long enough you could find 0:10:37.360 --> 0:10:39.640 out if they were true. But a lot of his 0:10:39.720 --> 0:10:42.600 predictions failed failed to play out the way he had said. 0:10:42.640 --> 0:10:44.880 Like he said, why two K was gonna lead to 0:10:45.120 --> 0:10:49.920 massive disaster? It didn't. It did cause problems, but nothing 0:10:50.400 --> 0:10:52.800 nearly on the level that what of what people were 0:10:52.840 --> 0:10:55.400 afraid of? He said the two thousand four Olympics would 0:10:55.400 --> 0:10:59.839 get canceled. They didn't. He also said that by the 0:11:00.040 --> 0:11:04.280 United States would split into warring factions and there'd be 0:11:04.280 --> 0:11:06.760 a great civil war, which did not happen. I mean, 0:11:06.760 --> 0:11:09.760 you could say that people are more polarized than ever before, 0:11:10.480 --> 0:11:14.080 but we haven't turned into tribal groups that are actually 0:11:14.120 --> 0:11:17.440 making war on each other in uh, in the way 0:11:17.480 --> 0:11:22.400 that he was suggesting. And he did say, however, that 0:11:22.679 --> 0:11:25.640 he was really from a parallel universe, one that was 0:11:26.280 --> 0:11:30.040 nearly identical to ours, but that there was probably a 0:11:30.040 --> 0:11:34.680 deviation between one to two per cent, so that things 0:11:34.720 --> 0:11:38.640 that happened in his universe may not happen exactly the 0:11:38.679 --> 0:11:42.559 same way in ours, but largely things would be more 0:11:42.640 --> 0:11:45.920 or less the same. He also said eventually that the 0:11:45.920 --> 0:11:49.599 future wasn't necessarily fixed, which is another get out of 0:11:49.679 --> 0:11:52.960 jail free car card if you're a time traveler. I 0:11:52.960 --> 0:11:56.680 guess uh. Eventually, there was some evidence that suggested that 0:11:56.760 --> 0:11:59.400 this was all the work of a couple of brothers 0:11:59.400 --> 0:12:03.280 in Florida who had sort of orchestrated the whole thing. 0:12:03.400 --> 0:12:06.240 There was another person who claimed that he was sort 0:12:06.240 --> 0:12:08.559 of consulted as part of this and that was kind 0:12:08.559 --> 0:12:11.920 of a collaborative storytelling exercise that sort of snowballed out 0:12:11.920 --> 0:12:16.600 of control. So chances are not a real time traveler. 0:12:17.400 --> 0:12:21.280 So then there was also the sad but fascinating tale 0:12:21.360 --> 0:12:24.840 of a man who used the pseudonym Bob White among others. 0:12:24.920 --> 0:12:27.440 This was back in the early two thousand's and this 0:12:27.520 --> 0:12:33.000 guy sent out emails in huge blasts, like millions of 0:12:33.000 --> 0:12:36.800 people were getting these emails, and essentially this was a 0:12:36.840 --> 0:12:40.240 spam email, but instead of trying to sell something, uh, 0:12:40.400 --> 0:12:45.679 this spam email was asking for some pretty crazy fictional technology. 0:12:45.679 --> 0:12:49.000 It was like a three page long manifesto and it 0:12:49.040 --> 0:12:52.280 included things saying that the person needed something like an 0:12:52.360 --> 0:12:56.040 AcBe five by twenty four series time transducing capacitor was 0:12:56.080 --> 0:13:00.680 built in temporal displacement, which is not a thing, but 0:13:00.880 --> 0:13:03.880 was asked for. So a guy named Dave Hill responded 0:13:04.000 --> 0:13:07.080 to this. He found it fascinating and he went so 0:13:07.160 --> 0:13:11.160 far as to even send an old hard drive, calling 0:13:11.200 --> 0:13:14.720 it a warp generator. But then he found out that 0:13:14.760 --> 0:13:18.160 the recipient wasn't just someone like making a joke on 0:13:18.160 --> 0:13:20.440 the internet. It was someone who actually seemed to truly 0:13:20.480 --> 0:13:24.680 believe in what they were saying, and they were showing 0:13:24.760 --> 0:13:28.560 some signs of paranoia and some other concerns. And it 0:13:28.559 --> 0:13:32.160 turned out that this was Robert Robbie Todino, who had 0:13:32.200 --> 0:13:34.959 been sending millions of emails since November two thousand one. 0:13:35.160 --> 0:13:37.440 He was in his twenties. He had founded a company 0:13:37.480 --> 0:13:40.560 called RT Marketing, which sent out spam messages about all 0:13:40.559 --> 0:13:43.440 sorts of products on behalf of various clients. But he 0:13:43.520 --> 0:13:46.360 was eventually hit with a five thousand dollar fine from 0:13:46.360 --> 0:13:48.840 the state of Massachusetts in a cease and desist order 0:13:48.840 --> 0:13:51.120 for that sort of stuff. That's around the time when 0:13:51.160 --> 0:13:53.400 he started sending out these anonymous calls for help in 0:13:53.440 --> 0:13:58.880 obtaining various science e sounding but largely fictional pieces of equipment. 0:13:59.200 --> 0:14:01.559 And he said that his life had been quote severely 0:14:01.600 --> 0:14:04.440 tampered with end quote and they needed to find a 0:14:04.480 --> 0:14:07.200 way to rewind time to fix it. And he called 0:14:07.240 --> 0:14:10.040 himself Bob Wyatt or Tim Jones or several other aliases 0:14:10.440 --> 0:14:13.840 as he corresponded with other people. His father said that 0:14:14.040 --> 0:14:19.120 Tudino had mental health problems, including dissociative disorder, and that 0:14:19.200 --> 0:14:21.920 the interactions with people had made it worse. Some people 0:14:21.960 --> 0:14:25.240 were likely taking advantage of him it's a very sad story. 0:14:25.920 --> 0:14:29.400 But he was seemingly convinced that time travelers were in 0:14:29.480 --> 0:14:34.560 fact real and walking among us, but no actual evidence 0:14:34.560 --> 0:14:36.960 came from that. So that's one way we can look 0:14:36.960 --> 0:14:39.120 for time travelers, look for people who claimed to be them. 0:14:39.160 --> 0:14:42.880 But maybe that won't work. Maybe people are maybe they're 0:14:42.880 --> 0:14:44.600 a little more shy. So what if we were to 0:14:45.200 --> 0:14:48.560 ask them to show up at a particular place in time. 0:14:49.120 --> 0:14:51.440 So that was the thought behind the m i T 0:14:51.720 --> 0:14:56.560 Time Traveler Convention. On May seven, two thousand five, students 0:14:56.560 --> 0:14:58.760 at m i T, who were led by an Electrical 0:14:58.800 --> 0:15:02.120 engineering and Computer scien it's graduate student named Amal Dora 0:15:02.160 --> 0:15:07.200 I held an official convention for time travelers and according 0:15:07.240 --> 0:15:10.920 to Dora, any real lifetime traveler was welcome to show 0:15:11.040 --> 0:15:14.120 up with no rs VP. They just had to bring 0:15:14.200 --> 0:15:17.640 proof that he or she was from the future. And 0:15:17.880 --> 0:15:21.120 and what I think was a pretty clever move. They 0:15:21.160 --> 0:15:23.960 focused very heavily on getting the word out to the press. 0:15:24.920 --> 0:15:31.320 And this wasn't just about night marketing a goofy silly event. 0:15:31.760 --> 0:15:36.800 It was a vital part of this experiment because by 0:15:36.840 --> 0:15:40.560 publicizing the event, by spreading the word wide, they could 0:15:41.200 --> 0:15:46.400 better ensure that people time travelers in the future learn 0:15:46.600 --> 0:15:50.400 about that convention, that party, and that as a result, 0:15:50.760 --> 0:15:53.280 they could travel back to that moment in time to 0:15:53.360 --> 0:15:57.200 attend the party. And as they said, this web page 0:15:57.240 --> 0:15:59.600 is insufficient. In less than a year, it will be 0:15:59.640 --> 0:16:03.040 taken down when I graduate. Spoiler alert, it wasn't taken down. 0:16:03.040 --> 0:16:06.280 It's still up. And furthermore, the World Wide Web is 0:16:06.360 --> 0:16:10.400 unlikely to remain in its present form permanently. Probably true, 0:16:10.400 --> 0:16:12.600 but it's still pretty much the way it was back then. 0:16:13.200 --> 0:16:16.200 We need volunteers to publish the details of the convention 0:16:16.280 --> 0:16:19.160 in enduring forms so that the time travelers of future 0:16:19.160 --> 0:16:22.800 millennia will be aware of the convention. This convention can 0:16:22.880 --> 0:16:26.280 never be forgotten. We need publicity in major outlets, not 0:16:26.360 --> 0:16:30.120 just Internet news. Think New York Times, Washington Post, books, 0:16:30.360 --> 0:16:33.160 that sort of thing. If you have any strings, please 0:16:33.520 --> 0:16:36.640 pull them. And you could ask, well, what what can 0:16:36.720 --> 0:16:39.600 I do? And they said that's great. Uh, write it 0:16:39.640 --> 0:16:42.160 down on a piece of acid free paper and slip 0:16:42.280 --> 0:16:46.239 those pieces of paper into obscure books in academic libraries, 0:16:46.640 --> 0:16:49.400 carve them into a clay tablet. If you write for 0:16:49.400 --> 0:16:52.400 a newspaper, insert a few details about the convention, tell 0:16:52.440 --> 0:16:54.360 your friends so that the word of the convention will 0:16:54.400 --> 0:16:57.640 be preserved in our oral history. Time travel is a 0:16:57.680 --> 0:17:00.280 hard problem and it may not be invented until long 0:17:00.320 --> 0:17:03.520 after m I t itself has faded into oblivion. Thus 0:17:03.760 --> 0:17:07.320 we ask you to include the latitude longitude information when 0:17:07.359 --> 0:17:10.520 you publicize the convention. You can also make an absolute 0:17:10.520 --> 0:17:14.080 commitment to publicize the convention afterwards. In that case, bring 0:17:14.119 --> 0:17:16.600 a time counsel or whatever it may be to the party, 0:17:16.720 --> 0:17:19.560 and then bury it afterwards. So I got a lot 0:17:19.560 --> 0:17:21.800 of coverage. They even got our rite up in Nature 0:17:21.840 --> 0:17:25.679 News that was called Time Travelers Snub Conference, So I 0:17:25.680 --> 0:17:28.440 guess you can see how that turned out. The website, 0:17:28.640 --> 0:17:30.640 which like I said, is still up to this day, 0:17:30.880 --> 0:17:37.080 says update. The convention was a mixed success. Unfortunately we 0:17:37.119 --> 0:17:40.680 had no confirmed time travelers visit us, yet many time 0:17:40.680 --> 0:17:44.920 travelers could have attended incognito to avoid endless questions about 0:17:44.960 --> 0:17:48.480 the future. We had a great series of lectures, awesome bands, 0:17:48.760 --> 0:17:51.880 and even a DeLorean. We regret having had to turn 0:17:51.880 --> 0:17:56.000 away visitors, but there was were capacity restrictions governing Morse Hall. 0:17:56.359 --> 0:17:58.600 Thanks so much to the dozens of people who helped, 0:17:59.560 --> 0:18:02.119 I've got a lot more to talk about trying to 0:18:02.359 --> 0:18:05.560 track down those pesky time travelers, but first let's take 0:18:05.760 --> 0:18:16.280 a little time out to thank our sponsor sticking with 0:18:16.320 --> 0:18:20.119 these events that are being held for time travelers. On 0:18:20.240 --> 0:18:24.119 June two thousand nine, Stephen Hawking held a party in 0:18:24.280 --> 0:18:30.240 Cambridge for time travelers. All time travelers were invited to come, 0:18:30.880 --> 0:18:34.000 but the catch was he did not issue the invitation 0:18:34.080 --> 0:18:37.800 to the party until after the party had already taken place. 0:18:38.760 --> 0:18:41.760 So the invitation flyer read you are cordially invited to 0:18:41.800 --> 0:18:45.320 a reception for time Travelers hosted by Professor Stephen Hawking, 0:18:45.480 --> 0:18:48.200 to be held at the University of Cambridge, Gonville and 0:18:48.280 --> 0:18:52.520 Caius College, Trinity Street, Cambridge. And then it's gave the 0:18:52.560 --> 0:18:56.680 exact global positioning coordinates for the party and said champagne 0:18:56.880 --> 0:18:59.920 would be served. But I guess it wasn't that rally 0:19:00.080 --> 0:19:04.000 party because it was it was held at noon, unless 0:19:04.480 --> 0:19:07.119 I don't know, kay, Cambridge, if you're out there, do 0:19:07.160 --> 0:19:14.360 you get turned up at noon? If so? Well done? Anyway, 0:19:14.800 --> 0:19:18.600 Later on, after the party had happened, he publicized the 0:19:18.640 --> 0:19:21.160 party in the press and on the web, and had 0:19:21.200 --> 0:19:24.479 an elegantly designed version of this flyer printed up and 0:19:24.520 --> 0:19:27.800 placed on sale, and said I'm hoping copies of it, 0:19:27.840 --> 0:19:30.760 in one form or another, will survive for many thousands 0:19:30.760 --> 0:19:33.720 of years. Maybe one day someone living in the future 0:19:33.760 --> 0:19:36.399 will find this information and use a wormhole time machine 0:19:36.440 --> 0:19:38.840 to come back to my party, proving that time travel 0:19:38.880 --> 0:19:43.040 will one day be possible. But no one showed up. 0:19:43.480 --> 0:19:46.320 Hawking later said during an interview at the two thousand 0:19:46.359 --> 0:19:50.120 twelve Seattle Science Festival, I have experimental evidence that time 0:19:50.160 --> 0:19:53.720 travel is not possible. I gave a party for time travelers, 0:19:53.880 --> 0:19:56.560 but I didn't send out the invitations until after the party. 0:19:56.800 --> 0:19:59.600 I sat there a long time, but no one came. 0:20:00.040 --> 0:20:03.400 So I guess Stephen Hawking just kind of watched champagne 0:20:03.440 --> 0:20:07.320 slowly go flat. So if they're not showing up to 0:20:07.320 --> 0:20:11.480 our parties, maybe maybe there's some you know, weird laws 0:20:11.520 --> 0:20:14.199 in the future about time travel and keeping it secret. 0:20:14.640 --> 0:20:17.520 What if we were to use big data to mind 0:20:17.960 --> 0:20:22.080 for the presence of time travelers. There is a paper 0:20:22.280 --> 0:20:27.359 that was written back in or released in It was 0:20:27.359 --> 0:20:31.679 written before that, titled searching the Internet for Evidence of 0:20:31.760 --> 0:20:35.439 Time Travelers. It was written by Robert J. Nemerov and 0:20:35.560 --> 0:20:40.920 Theresa Wilson over at the Michigan Technological University's physics department, 0:20:41.560 --> 0:20:44.680 and they looked for evidence of time travelers by sifting 0:20:44.760 --> 0:20:47.879 through enormous amounts of data on the Internet. And the 0:20:47.960 --> 0:20:50.800 idea was that if travelers from the future were to 0:20:50.880 --> 0:20:54.600 come to the Internet age, they might not, you know, 0:20:54.760 --> 0:20:58.479 come forward and proclaim themselves as time travelers, but they 0:20:58.560 --> 0:21:01.600 might leave some sort of race of their presence on 0:21:01.760 --> 0:21:05.439 the web if you just looked for things that showed 0:21:05.480 --> 0:21:09.480 evidence of what they called prescient knowledge, in other words, 0:21:09.800 --> 0:21:14.520 looking for any indications that someone knows about something before 0:21:14.600 --> 0:21:18.840 that something actually happens. And they used three main methods 0:21:18.880 --> 0:21:21.639 to do this. First, they looked back at the web 0:21:21.720 --> 0:21:24.679 for terms that would not have made any sense at 0:21:24.720 --> 0:21:27.639 the time they were published, but which now referred to 0:21:27.720 --> 0:21:31.800 something meaningful. They gave examples. They said, search terms related 0:21:31.840 --> 0:21:35.040 to comment I sn I S O N, which was 0:21:35.119 --> 0:21:38.520 not discovered until September twenty first, two thousand twelve. Or 0:21:38.640 --> 0:21:44.639 Pope Francis, which was formerly Cardinal Jorge Mario Burgoglio uh. 0:21:44.840 --> 0:21:48.000 He chose the name Francis in March two thousand thirteen, 0:21:48.520 --> 0:21:52.080 but before March two thirteen there was no Pope Francis. 0:21:52.119 --> 0:21:54.840 There never been a Pope Francis, he's the first one. 0:21:54.960 --> 0:21:59.440 So if they said we find evidence of these terms 0:21:59.440 --> 0:22:04.160 existing before those dates, that could indicate a time traveler 0:22:04.480 --> 0:22:08.320 who was googling around or maybe popping on Facebook or 0:22:08.320 --> 0:22:12.399 Twitter or something and looking for these terms, but it 0:22:12.480 --> 0:22:16.520 was before those things had happened. The next method they 0:22:16.600 --> 0:22:20.280 used was they looked for prescient search terms in search 0:22:20.320 --> 0:22:24.359 engine history. So again, if let's say that they're not 0:22:24.440 --> 0:22:26.960 posting to Facebook or Twitter or whatever. Also, Facebook is 0:22:27.040 --> 0:22:29.520 problematic because you could back date posts for a really 0:22:29.560 --> 0:22:33.800 long time, so you could actually cheat. You could post 0:22:33.920 --> 0:22:36.119 about you could set the date on a post to 0:22:36.240 --> 0:22:39.680 being before the thing actually happened, so that would be 0:22:39.840 --> 0:22:41.679 it would look like you were a time traveler, but 0:22:41.720 --> 0:22:43.960 it was just because Facebook allowed you to do it. Anyway, 0:22:44.440 --> 0:22:47.320 they said, let's see if there's any evidence of search 0:22:47.480 --> 0:22:51.200 terms being used before these things happened. Google trends didn't 0:22:51.240 --> 0:22:54.000 really turn up any interesting results. But then they pointed 0:22:54.000 --> 0:22:58.119 out Google aggregates this data and it very well. Maybe 0:22:58.240 --> 0:23:00.760 that if it's a time traveler who's come back to 0:23:00.880 --> 0:23:03.760 present day, there might not be enough information there for 0:23:03.800 --> 0:23:07.840 you to draw an in conclusions. Uh, one of the 0:23:07.880 --> 0:23:10.920 studies authors happened to have access to the back end 0:23:10.920 --> 0:23:14.639 for NASA's Astronomy Picture of the Day subsite, so he 0:23:14.720 --> 0:23:17.560 checked to see if anyone had searched for any evidence 0:23:17.600 --> 0:23:21.680 of common ice and before it had been discovered. And Third, 0:23:21.920 --> 0:23:24.480 they invited the future people to travel into the past 0:23:25.160 --> 0:23:28.640 before the end of August tweet at them with one 0:23:28.800 --> 0:23:31.360 of two hashtags. They said, if you're a time traveler, 0:23:31.760 --> 0:23:34.159 go back to the past. Use Twitter and send on 0:23:34.240 --> 0:23:36.720 the message and include one of these two hashtags. Either 0:23:37.160 --> 0:23:41.800 hashtag I can change the past. Two. That would be 0:23:42.080 --> 0:23:45.400 if the time travelers says yes, I can travel through 0:23:45.440 --> 0:23:49.800 time and history is plastic, which means the past is changeable. 0:23:50.080 --> 0:23:53.040 You can go back in time and change things, and 0:23:53.200 --> 0:23:56.400 the present and the future are not set in stone. 0:23:56.920 --> 0:24:01.240 The second was hashtag I cannot change the past two, 0:24:01.840 --> 0:24:04.240 and that would be if time travel works, but it 0:24:04.280 --> 0:24:07.920 works in a fixed history scenario, which means it's possible. 0:24:08.480 --> 0:24:12.959 But the stuff that we experience is already part of 0:24:13.000 --> 0:24:15.040 the whole time travel thing. Like you, you wouldn't be 0:24:15.040 --> 0:24:16.959 able to change the future. It would have to be 0:24:17.400 --> 0:24:20.240 stuff that it's the way it's always happened. It's a 0:24:20.240 --> 0:24:24.160 little confusing. It actually goes into a principle called self consistency. 0:24:24.880 --> 0:24:28.760 They were careful to not use the hashtag in search 0:24:29.000 --> 0:24:32.800 until after their advertisement asking for past tweets in order 0:24:32.840 --> 0:24:36.360 to prevent time paradoxes, and it didn't turn up any results. 0:24:37.119 --> 0:24:39.560 So in the end they discovered no prescient knowledge through 0:24:39.600 --> 0:24:42.680 any of these inquiries. So that leads to the question 0:24:42.720 --> 0:24:46.200