WEBVTT - Listener Questions 0:00:07.280 --> 0:00:09.480 One of my favorite things when we give our lecture 0:00:09.520 --> 0:00:12.080 about what we don't know about the universe is the 0:00:12.160 --> 0:00:14.920 questions we get from people in the audience. The best 0:00:15.000 --> 0:00:17.960 questions always come from the youngest audience members. I remember 0:00:17.960 --> 0:00:20.840 one time I gave a talk about liquid nitrogen in 0:00:20.880 --> 0:00:23.400 front of elementary school kids and some kid asked me 0:00:23.440 --> 0:00:27.040 the question. He said, if lightsabers were real, would they 0:00:27.040 --> 0:00:30.920 be made of liquid nitrogen? And Uh, that's I don't 0:00:30.920 --> 0:00:32.400 even know how to answer that question. I was like 0:00:32.560 --> 0:00:36.320 totally stumped by like a six year old. Wait, wait, wait, wait, 0:00:36.360 --> 0:00:42.320 Star Wars is not real. Lightsabers are fictional. Horr heead fictional? Yes, 0:00:42.560 --> 0:00:44.600 so you need to find some other defense against the 0:00:44.640 --> 0:00:49.040 invading arm sampire. So the questions are a fantastic way 0:00:49.080 --> 0:00:52.279 to understand have I really communicated anything? Have people really 0:00:52.320 --> 0:00:54.520 understood what I'm doing? And so that's why I love 0:00:54.640 --> 0:00:57.520 the live aspect of a presentation, because you get that 0:00:57.560 --> 0:00:59.920 feedback from the audience. They're getting it, they're asking fall 0:01:00.080 --> 0:01:03.120 up questions, or they're totally confused and they're asking you questions. 0:01:03.120 --> 0:01:06.160 It seemed to make no sense. Yeah, if only you 0:01:06.280 --> 0:01:10.959 had jedim line tricks, Daniel, These are not the questions 0:01:11.000 --> 0:01:32.640 you're looking for. This is the podcast you're looking for. However. Hi, 0:01:32.720 --> 0:01:36.319 I'm Jorhan and I'm Daniel. Welcome to our podcast. Daniel 0:01:36.319 --> 0:01:39.319 and Jorge explained the universe in which we try to 0:01:39.400 --> 0:01:42.679 make the universe understandable to you, and this time we're 0:01:42.800 --> 0:01:45.640 really going to do our best. Yeah. Today on the program, 0:01:45.800 --> 0:01:52.200 we're going to be answering questions from you the listeners. 0:01:52.320 --> 0:01:54.920 That's right. People have been sending us questions over email, 0:01:55.000 --> 0:01:57.000 and some of them really tickled our brain and said 0:01:57.000 --> 0:01:59.920 we thought let's dig into them because we thought other 0:02:00.040 --> 0:02:02.560 people must have the same questions. Yeah, we have questions 0:02:02.560 --> 0:02:05.880 here about the speed of light, about using giant lasers, 0:02:06.200 --> 0:02:10.280 and about where is the center of the universe. That's right, 0:02:10.320 --> 0:02:12.280 And these are just three questions that we chose from 0:02:12.320 --> 0:02:14.440 the pile. There are other questions I wish we could 0:02:14.440 --> 0:02:16.360 dig into, but we don't have time, like some of 0:02:16.360 --> 0:02:19.240 the joke questions. Yeah, and so as a reminder, if 0:02:19.240 --> 0:02:22.079 you have any questions even after today, after we answer 0:02:22.160 --> 0:02:24.440 some of your questions, if you're a different listener and 0:02:24.480 --> 0:02:26.480 have a question, you can always send us a question 0:02:26.600 --> 0:02:30.440 at Questions at Daniel and Jorge dot com. That's right. 0:02:30.520 --> 0:02:35.800 Send us questions about anything, life, the universe, dating, bananas, whatever. 0:02:36.120 --> 0:02:39.360 We don't promise to be experts in all these fields. 0:02:40.120 --> 0:02:42.760 You don't want to answer dating questions. Yeah, we can 0:02:42.760 --> 0:02:45.679 give an answer about dating, but you know, maybe you 0:02:45.720 --> 0:02:49.160 shouldn't follow dating advice from a cartoonists and a physicist. 0:02:49.160 --> 0:02:51.519 I don't know that you're any more or less qualified 0:02:51.560 --> 0:02:53.519 to give dating advice than anybody else out there giving 0:02:53.600 --> 0:02:56.480 dating advice. Horror, everybody's only got their own experience. You know, 0:02:56.800 --> 0:02:59.560 you should definitely not get dating advice from me because 0:02:59.600 --> 0:03:03.080 I haven't dated anyone since I was like sixteen. But 0:03:03.160 --> 0:03:05.840 it was a success, right, So there you go, you 0:03:05.880 --> 0:03:11.040 have a hundred percent success, right, I have a yeah, yeah, 0:03:11.160 --> 0:03:13.240 I have one data point Every date you take leads 0:03:13.240 --> 0:03:16.160 to marriage, right, Yeah, there you go. Um yeah, so 0:03:16.840 --> 0:03:19.640 listener questions so um, And this is one of your 0:03:19.639 --> 0:03:23.000 favorite parts of teaching and giving cogs, right, Daniel. We 0:03:23.000 --> 0:03:25.920 give a lot of talks across the country in other 0:03:25.960 --> 0:03:30.160 countries about our book, and we always get great questions 0:03:30.160 --> 0:03:32.640 at the end, right, Absolutely, we always get great questions. 0:03:32.680 --> 0:03:35.400 Sometimes people show up with a question already. You can 0:03:35.400 --> 0:03:38.760 tell they're burning to ask some physicists, um, and sometimes 0:03:38.800 --> 0:03:40.840 they have a question that's inspired bout what we've said. 0:03:41.360 --> 0:03:44.400 And you know, sometimes the questions are pretty random, but 0:03:44.440 --> 0:03:47.240 it's always a lot of fun because you can really 0:03:47.280 --> 0:03:48.960 try to explain it to the person and when they 0:03:49.000 --> 0:03:50.960 get it, you can see that light go on in 0:03:50.960 --> 0:03:53.840 their eyes when they finally the pieces of clicked together 0:03:54.200 --> 0:03:56.800 and they have some understanding. And I love that feeling 0:03:56.800 --> 0:03:59.839 of like having an idea in my head translating into 0:04:00.040 --> 0:04:03.960 land waves which then wiggle across space and get translated 0:04:04.000 --> 0:04:06.880 back into an idea in their brain. I mean, it's incredible, 0:04:07.000 --> 0:04:09.240 right that you can even translate an idea from one 0:04:09.280 --> 0:04:12.320 brain to another. So when it's successful, I feel I 0:04:12.320 --> 0:04:16.080 feel pretty good. Yeah, we'll enjoy that feeling before um, 0:04:16.120 --> 0:04:17.960 you know, we're all plugged into the matrix and it's 0:04:18.000 --> 0:04:21.080 just all automatic, that's right, And then we won't need 0:04:21.120 --> 0:04:24.119 podcasts because we'll all know what everybody knows all the time. 0:04:24.440 --> 0:04:28.520 There'll be no privacy. All right, let's just jump into 0:04:28.520 --> 0:04:35.479 the questions, alright. Our first question comes from Sandy from 0:04:35.520 --> 0:04:38.040 New York and he has a question about the speed 0:04:38.120 --> 0:04:41.600 of light. Hi Daniel and Horror. My name is Sandy Delone, 0:04:41.600 --> 0:04:44.480 originally from New York City. I was hoping you can 0:04:44.520 --> 0:04:47.360 talk about whether the speed of light has always been 0:04:47.360 --> 0:04:50.200 the same or whether it is a function of space time. 0:04:50.720 --> 0:04:52.919 How do we know whether or not the speed of 0:04:53.000 --> 0:04:56.240 light has been slowing down over time? Wow, that is 0:04:56.240 --> 0:04:58.719 a great question. Yeah. Well, first of all, he said 0:04:58.760 --> 0:05:01.240 he's originally from New York. What does that mean? That's 0:05:01.279 --> 0:05:03.880 so mysterious. Where is he that? Well, right now he's 0:05:03.880 --> 0:05:05.760 on a rocket ship and at nearly the speed of 0:05:05.839 --> 0:05:13.320 light hitting someone hoping speed right away. This pressing question. 0:05:14.320 --> 0:05:16.479 Wherever he is he can get the podcast, so he 0:05:16.480 --> 0:05:19.240 can't be that far away unless he's from the future, 0:05:20.480 --> 0:05:23.039 that's right, in which case, he invited time travel and 0:05:23.120 --> 0:05:24.760 he knows more about the speed of light than I do, 0:05:25.240 --> 0:05:28.560 so I should be asking him, would be asking him questions. Yeah, 0:05:29.080 --> 0:05:31.800 you're saying these questions. Come to my house and show 0:05:31.839 --> 0:05:35.760 me your time machine. But this is a great question. Basically, 0:05:35.800 --> 0:05:38.560 it's the question of whether the speed of light has 0:05:38.640 --> 0:05:42.520 ever changed. But the first thing I thought was, holy cow, 0:05:42.680 --> 0:05:45.000 can the speed of light change? Is that even possible? 0:05:45.520 --> 0:05:48.200 Is that something that might actually happen and not totally 0:05:48.279 --> 0:05:50.760 break down the universe. Um, all right, So I'm gonna 0:05:50.760 --> 0:05:53.960 make a classic mistake by saying, yes, all right, so 0:05:54.040 --> 0:05:56.320 it's possible for the speed of light to not always 0:05:56.320 --> 0:05:59.880 have been the same. However, as a classical mistake, because 0:06:00.000 --> 0:06:01.240 those people are just gonna hear that and then go 0:06:01.320 --> 0:06:03.520 off and say this physicist said the speed of light 0:06:03.600 --> 0:06:08.159 might change. It's possible. And however, nobody takes that idea 0:06:08.320 --> 0:06:11.200 very seriously. It's pretty well understood that the speed of 0:06:11.279 --> 0:06:13.320 light is fixed, and we assume that it's not changing 0:06:13.360 --> 0:06:15.279 in time. We have no evidence to say that it 0:06:15.360 --> 0:06:17.000 is changing in time, and we can dig in a 0:06:17.040 --> 0:06:19.760 minute to the experiments that we've done, and the evidence 0:06:19.800 --> 0:06:22.920 we have to suggests is constant. However, you know, there's 0:06:22.920 --> 0:06:24.480 a limit to the kind of things we can know, 0:06:24.839 --> 0:06:27.600 and some things are based on assumptions, and so the 0:06:27.640 --> 0:06:29.760 speed of light is one of those things, like we've 0:06:29.839 --> 0:06:32.039 never seen it change. We have no reason to imagine 0:06:32.080 --> 0:06:35.240 it would have changed or will change. But you know, 0:06:35.279 --> 0:06:38.480 there are things we don't know. So, for example, we've 0:06:38.520 --> 0:06:40.960 measured the speed of light a bunch of times, but 0:06:41.040 --> 0:06:43.279 we don't know why it is what it is. You know, 0:06:43.320 --> 0:06:45.479 it's a number three times tend to the eight meters 0:06:45.520 --> 0:06:48.520 per second. We have no reason to feel like it 0:06:48.560 --> 0:06:50.840 should be that number or some other number. You know, 0:06:50.880 --> 0:06:52.719 if we had measured it to be a different number, 0:06:52.720 --> 0:06:54.840 we would have been like, Okay, that's the speed of 0:06:54.920 --> 0:06:57.039 light instead of this other number. So it's not like 0:06:57.080 --> 0:06:59.719 it has a special value. There's nothing in the math 0:07:00.000 --> 0:07:03.279 attics of the laws of physics that'd say the speed 0:07:03.279 --> 0:07:05.359 of light has to be this as far as we know. 0:07:05.800 --> 0:07:07.760 I mean, somebody could come up with a deeper theory 0:07:07.760 --> 0:07:09.840 of physics that doesn't have the speed of light as 0:07:09.840 --> 0:07:12.680 an arbitrary parameter that predicts the speed of light, you know, 0:07:12.960 --> 0:07:14.920 that says it has to be this way because space 0:07:15.000 --> 0:07:17.160 is made out of these quantum loops and that's and 0:07:17.200 --> 0:07:20.240 they oscillated some certain frequency, and that determines the speed 0:07:20.280 --> 0:07:22.560 of light. Maybe right, But we're not there yet at 0:07:22.560 --> 0:07:25.240 this point. It's just a number we measure about the universe, 0:07:25.600 --> 0:07:27.200 and I physicists love doing that. We go and we 0:07:27.240 --> 0:07:29.720 measure these constants because we think there are clues about 0:07:29.760 --> 0:07:32.480 the way the universe is put together. Yeah, but I 0:07:32.480 --> 0:07:35.000 guess what would happen if the speed of light did change? 0:07:35.120 --> 0:07:37.760 Like if suddenly it was twice as fast as it 0:07:37.880 --> 0:07:41.880 is now. Would anything change for us right now, like 0:07:42.400 --> 0:07:44.560 in our everyday lives. Well, if it changed, so the 0:07:44.640 --> 0:07:48.800 universities fall apart. Yeah, like suddenly, wow, suddenly, a sudden 0:07:48.880 --> 0:07:50.480 change in the speed of light. That is an awesome 0:07:50.520 --> 0:07:53.040 thought experiment. Um, I think a lot of things might 0:07:53.080 --> 0:07:57.120 break because, um, you know, we assume speed of light 0:07:57.240 --> 0:07:59.800 is the speed of light, and we use that for 0:08:00.040 --> 0:08:02.040 lots of things, like in the Internet, for to measure 0:08:02.080 --> 0:08:04.400 timing of stuff. You know, we assume things travel as 0:08:04.440 --> 0:08:08.400 certain speed. Wait, wait, wait, it might affect my web surfing. Right, 0:08:08.920 --> 0:08:12.040 that's right, that's all right, let's don't even think about that. 0:08:12.040 --> 0:08:14.600 That's too scary. Yeah, but you know, and on a 0:08:14.680 --> 0:08:16.880 deeper level, if you're like a philosophical kind of person, 0:08:17.080 --> 0:08:19.560 you can ask even deeper questions like do we know 0:08:19.640 --> 0:08:22.480 that the laws of physics themselves change? You know, we 0:08:22.560 --> 0:08:25.080 have these laws like general relativity and quantum mechanics, and 0:08:25.080 --> 0:08:28.720 they're pretty well established over you know, hundred years of experiments, etcetera. 0:08:29.400 --> 0:08:32.040 And they don't seem to be changing. But that doesn't 0:08:32.080 --> 0:08:35.679 mean they won't, right. The assumption that experiments are repeatable 0:08:35.760 --> 0:08:39.160 is foundational concept of empiricism we have in science is 0:08:39.200 --> 0:08:42.559 itself an assumption. You know that the universe has laws, 0:08:42.720 --> 0:08:45.160 and those laws don't change over time, so that we 0:08:45.240 --> 0:08:48.640 can bit by bit do experiments to reveal them. That's 0:08:48.679 --> 0:08:51.320 just an assumption. It seems to work, it works great, 0:08:51.360 --> 0:08:54.800 it works amazingly. We've never seen hints of things changing. 0:08:55.080 --> 0:08:57.400 But we don't know why the universe has laws that 0:08:57.440 --> 0:09:00.599 are discoverable and then don't change. So that assumption is 0:09:00.880 --> 0:09:02.840 based on a lot of data, but it's not based 0:09:02.840 --> 0:09:06.600 on like a bedrock principle. It's like, there's no fundamental 0:09:06.679 --> 0:09:09.840 reason why, and so it could certainly change, or it 0:09:09.840 --> 0:09:13.040 could be changing really gradually over time. So we haven't 0:09:13.080 --> 0:09:17.840 noticed yet. So it can change, but we just haven't. 0:09:18.080 --> 0:09:20.160 We don't think it's changing, that's right, But I guess 0:09:20.160 --> 0:09:23.320 the question is has it ever changed in the past, Like, 0:09:23.360 --> 0:09:27.160 how do we know it wasn't different before? Right exactly? 0:09:27.200 --> 0:09:29.679 And so we have this awesome tool for looking into 0:09:29.679 --> 0:09:32.360 the past, and it's called the universe. So you can 0:09:32.360 --> 0:09:34.520 look out intil the night sky and you can see 0:09:34.559 --> 0:09:37.679 what happened eight minutes ago. If you look at the sun, right, 0:09:37.720 --> 0:09:40.160 don't stare directly at the sun of course. But you know, 0:09:40.240 --> 0:09:41.960 the Sun you're looking at is not the Sun as 0:09:41.960 --> 0:09:44.080 it looks like now. It's how the Sun looked eight 0:09:44.120 --> 0:09:47.000 minutes ago. And the further out you look, the further 0:09:47.040 --> 0:09:49.160 back in time you look, and we can see all 0:09:49.200 --> 0:09:51.600 the way back to the very early moments of the universe, 0:09:52.000 --> 0:09:54.120 and we can see physics happening. You know. We see 0:09:54.120 --> 0:09:57.000 things rotating, we say things orbiting, we see things smashing 0:09:57.040 --> 0:09:59.640 into each other. And we apply the laws of physics 0:09:59.640 --> 0:10:01.960 that we learn about here on Earth in our environment 0:10:02.320 --> 0:10:05.200 to those systems that we see deep in the deep past, 0:10:05.559 --> 0:10:08.080 and things make sense, and they make sense using the 0:10:08.160 --> 0:10:10.880 same speed of light. So we see the speed of 0:10:10.960 --> 0:10:14.520 light unchanged way way back into the history of the universe. 0:10:15.720 --> 0:10:17.440 So that gives us a lot of confidence that things 0:10:17.440 --> 0:10:19.920 haven't changed. Oh I see, So we when we look 0:10:19.920 --> 0:10:21.960 at a star that's really far away, we're seeing the 0:10:22.040 --> 0:10:25.760 results of physics not only that far away, but that 0:10:25.840 --> 0:10:29.280 long ago. Yeah, exactly, And so that gives us confidence that, 0:10:29.360 --> 0:10:31.400 you know, the universe pretty much works the same way 0:10:31.440 --> 0:10:33.800 now as it did billions of years ago. That's right. 0:10:33.960 --> 0:10:35.640 And you know the concept that the speed of light 0:10:35.640 --> 0:10:37.880 may have been different a long time ago UM is 0:10:37.920 --> 0:10:42.280 sometimes proposed by advocates of creation theory. You know, they say, well, 0:10:42.280 --> 0:10:44.719 the universe is only a few thousand years old, and 0:10:44.760 --> 0:10:47.160 then they have a problem. They have to explain, how 0:10:47.160 --> 0:10:49.800 do the light from stars get here if it's if 0:10:49.800 --> 0:10:51.880 they're so far away in the universe is only six 0:10:51.880 --> 0:10:55.440 thousand years old, right, this night sky should be totally black. Um. 0:10:55.480 --> 0:10:57.520 And so they proposed that maybe the speed of light 0:10:57.559 --> 0:10:59.360 was super duper fast a long time ago, so the 0:10:59.400 --> 0:11:02.760 light sort of here and then it's slowed down and 0:11:02.800 --> 0:11:05.080 then you know, and then and that's the way the 0:11:05.160 --> 0:11:07.840 light got here in such a short time. So, you know, 0:11:08.320 --> 0:11:10.720 that seems kind of crazy to me, but that's one 0:11:10.760 --> 0:11:13.280 motivation for imagining the speed of light might have been different. 0:11:13.600 --> 0:11:15.640 And there are other ones that are, i mean, they're 0:11:15.640 --> 0:11:17.920 still on the on the on the fringe, but they're 0:11:17.920 --> 0:11:20.640 not as fringees creation theory, and they have to do 0:11:20.720 --> 0:11:23.440 with the very early moments of the universe, the inflation, 0:11:23.480 --> 0:11:25.160 because you know, we can look out into space and 0:11:25.240 --> 0:11:28.079 we can see the speed of light is basically unchanged 0:11:28.160 --> 0:11:31.600 until the fairly early universe a few hundred thousand years 0:11:31.640 --> 0:11:34.600 after the Big Bang, but before that is very hard 0:11:34.640 --> 0:11:37.280 to see because the universe was trent, was not transparent 0:11:37.360 --> 0:11:39.880 back then. And we have these questions about what happened 0:11:39.920 --> 0:11:42.199 the very early universe. And one of the theories is 0:11:42.240 --> 0:11:45.440 called inflation and explains how the universe got so big 0:11:45.520 --> 0:11:49.280 so quickly, right and and and it's so smooth. And 0:11:49.360 --> 0:11:51.400 one way that people explain that is that the universe 0:11:51.440 --> 0:11:55.240 got really stretched out, the space itself got stretched out, 0:11:55.679 --> 0:11:59.000 and that's called inflationary theory, says the universe expanded really 0:11:59.080 --> 0:12:02.840 rapidly early on um. And but there are other ideas. 0:12:02.960 --> 0:12:05.160 And one of those other ideas is that in the 0:12:05.240 --> 0:12:08.680 very first moments after the Big Bang, maybe the speed 0:12:08.679 --> 0:12:11.320 of light was much much faster, and that account for 0:12:11.320 --> 0:12:14.240 how things moved more quickly in the first few moments 0:12:14.280 --> 0:12:17.480 after the universe was born. Oh, I see, but you 0:12:17.480 --> 0:12:20.920 don't need that if you have the expansion of space itself. Yeah, 0:12:20.960 --> 0:12:23.880 Inflation is a much more comprehensive theory. Explains a lot 0:12:23.920 --> 0:12:27.000 of things that's been tested much more rigorously. This is 0:12:27.040 --> 0:12:29.600 sort of a crazy idea people think about, and I 0:12:29.679 --> 0:12:32.840 totally encourage crazy ideas. I mean, crazy thinking is what 0:12:32.920 --> 0:12:35.720 leads to breakthroughs, not every time, not every crazy theory 0:12:35.760 --> 0:12:38.040 is the right theory. But you've got to allow for 0:12:38.080 --> 0:12:41.200 people to think outside the scientific mainstream in order to 0:12:41.400 --> 0:12:43.720 you know, sometimes generated crazy idea which turns out to 0:12:43.720 --> 0:12:46.719 be true. We've had revolutions in physics and those came 0:12:46.760 --> 0:12:49.520 from crazy ideas. All right, So Sammy from New York, 0:12:49.600 --> 0:12:53.240 that's your answer. We know because we can see well 0:12:53.280 --> 0:12:55.520 into the past, and we have theories that project well 0:12:55.559 --> 0:12:57.480 into the past, and that that tells us that the 0:12:57.520 --> 0:13:01.000 speed of light hasn't been changing. That's right with that, 0:13:01.360 --> 0:13:16.559 Let's take a break. Our next question comes from Ariel 0:13:16.679 --> 0:13:20.000 from Russia, and he had a question about, or more 0:13:20.080 --> 0:13:22.920 like a suggestion about what we could do if there's 0:13:22.920 --> 0:13:26.920 a big asteroid coming to kills All. Hi, Daniel and Jorge. 0:13:27.400 --> 0:13:29.880 My name is Ariel. I want to ask you what 0:13:29.920 --> 0:13:32.680 if instead of using a projectile launched from Earth to 0:13:32.760 --> 0:13:36.360 intercept an incoming asteroid, we use an array of lasers 0:13:36.520 --> 0:13:41.000 and blast asteroid without living Earth. Wow, a great suggestion. 0:13:41.160 --> 0:13:43.920 I think Ariel just wants to build a huge laser 0:13:44.000 --> 0:13:46.520 and point out in the space. Right. That is an 0:13:46.559 --> 0:13:51.600 awesome question, um, and it's pretty wild. I wonder what 0:13:51.800 --> 0:13:53.800 he was doing when he thought of this question, he's 0:13:53.840 --> 0:13:56.280 probably building a huge laser and preparing to point out 0:13:56.280 --> 0:14:00.640 in his face right right. So the background year, of course, 0:14:01.000 --> 0:14:02.560 I mean, why would you want to shoot a laser 0:14:02.559 --> 0:14:06.160 at asteroids other than that sounds really fun, um. And 0:14:06.200 --> 0:14:08.760 the reason is that we did an episode about death 0:14:08.920 --> 0:14:12.120 from space or death from above, right, the danger from 0:14:12.280 --> 0:14:15.480 killer rocks floating out in space, landing on Earth and 0:14:15.520 --> 0:14:17.760 wiping us all out like the dinosaurs. And in that 0:14:17.920 --> 0:14:20.240 podcast we talked about what we could do if we 0:14:20.280 --> 0:14:22.800 see one coming at us, and we talked about how 0:14:22.880 --> 0:14:25.320 we can send rockets out there to kind of deflect 0:14:25.320 --> 0:14:27.520 the asteroid or blow it up or try to break 0:14:27.520 --> 0:14:30.080 it up. Right, that's right, um. And one of the 0:14:30.160 --> 0:14:33.960 challenges is finding the asteroid early, because the sooner you 0:14:34.040 --> 0:14:36.280 find it, the less you have to deflect it. Right, 0:14:36.400 --> 0:14:38.520 If it's really far away, you can give it a 0:14:38.560 --> 0:14:41.120 pretty tiny nudge, and by the time the asteroid gets 0:14:41.120 --> 0:14:43.160 to Earth, that tiny nudge is going to turn into 0:14:43.240 --> 0:14:46.160 a big deviation in its path. If you only find 0:14:46.200 --> 0:14:48.960 it like one second before it hits the atmosphere, then 0:14:48.960 --> 0:14:51.200 a tiny nudge is going to do nothing. So the 0:14:51.320 --> 0:14:54.480 earlier you spotted, the smaller the nudge has to be. 0:14:54.880 --> 0:14:57.480 And then one problem is, say you spot this asteroid. 0:14:57.680 --> 0:15:00.000 If you want to send up a nuclear weapon or 0:15:00.040 --> 0:15:02.360 a gravity tractor or something to tug it off, course, 0:15:03.400 --> 0:15:04.840 you have to get it up there and get it 0:15:04.880 --> 0:15:08.640 to the asteroid really fast, right, because every second counts. 0:15:08.800 --> 0:15:11.440 And so I think that's what motivated Arial's question. He's thinking, 0:15:11.640 --> 0:15:13.800 let's get something there that travels at the speed of 0:15:13.880 --> 0:15:17.880 light like light, right, and using lasers, can we build 0:15:17.880 --> 0:15:20.040 a death star? Can we turn the Earth into a 0:15:20.120 --> 0:15:22.720 death star? You know, have the guys in the black 0:15:22.720 --> 0:15:26.360 helmets pull that lever, have the green laser shootout and 0:15:26.400 --> 0:15:31.119 destroyed the asteroid. That's right, this fully operational battle station exactly. 0:15:31.960 --> 0:15:34.440 That's everybody's fantasy to pull that big lever. You know. 0:15:34.520 --> 0:15:37.680 I love pressing buttons and pulling levers, and the same 0:15:37.760 --> 0:15:40.280 things happen, So that would be a lot of fun. Um. Well, 0:15:40.440 --> 0:15:43.160 great question, Aril, and we didn't cover our podcast. You're right, 0:15:43.400 --> 0:15:45.320 and the reason is that it's a fairly new idea. 0:15:45.440 --> 0:15:47.880 So there's a short answer to your question. Yes, it's 0:15:47.920 --> 0:15:51.480 absolutely possible. People are working on it right now and 0:15:51.480 --> 0:15:55.600 they're developing this technoques. Yes, it's a grown ups working 0:15:55.640 --> 0:15:59.760 on this. Yeah, there are grown ups building death rays 0:15:59.840 --> 0:16:02.680 to shoot at rocks in space. That is somebody's job. 0:16:02.720 --> 0:16:05.000 I mean people, if you work hard, if you study, 0:16:05.440 --> 0:16:07.120 you could get to work on that kind of question. 0:16:07.560 --> 0:16:11.600 And there's a labit. You didn't realize that was an 0:16:11.600 --> 0:16:16.080 alternate career path? Should build gine a death star lasers? No? 0:16:16.240 --> 0:16:17.880 I didn't know. Yeah, well you know my life would 0:16:17.920 --> 0:16:20.160 have been so much different. Yeah, we should educate children 0:16:20.200 --> 0:16:23.440 about all of their options. Um, there's a labit you see, 0:16:23.480 --> 0:16:26.760 Santa Barbara that's working on exactly this. And the reason 0:16:27.000 --> 0:16:29.040 it's not one of the older ideas. You don't hear 0:16:29.040 --> 0:16:30.920 about this when you read like books from the seventies 0:16:31.000 --> 0:16:34.440 or eighties about asteroids and asteroid deflections is that only 0:16:34.480 --> 0:16:37.680 recently do we have lasers that are powerful enough to 0:16:37.720 --> 0:16:39.480 make this efficient. I mean, you've got to put a 0:16:39.560 --> 0:16:42.280 lot of energy into a laser if it's gonna blast 0:16:42.360 --> 0:16:45.600 something super far away. Right, lasers are really focused, right, 0:16:45.680 --> 0:16:48.960 the photons are almost parallel. But if you shoot a 0:16:48.960 --> 0:16:50.840 beam of light, it's going to get wider and wider 0:16:50.840 --> 0:16:53.960 and wider as it goes, which means less and less intense. Right, 0:16:54.640 --> 0:16:57.680 For example, you can shine your flashlight at the Moon 0:16:57.800 --> 0:16:59.760 and you can hit the moon no problem, right, because 0:16:59.800 --> 0:17:02.360 by the time you're the beam from your flashlight gets 0:17:02.560 --> 0:17:05.760 to the Moon, it's huge. It's wider than the moon. Right, 0:17:06.440 --> 0:17:08.560 So the key one of one of the photons you 0:17:08.600 --> 0:17:11.840 shoot is going to hit the moon, exactly. But the 0:17:11.920 --> 0:17:15.520 idea behind laser asteroid deflection is that you want to 0:17:15.720 --> 0:17:18.320 heat up a spot on the side of the asteroid, 0:17:18.720 --> 0:17:21.800 so it warms up to like three thousand degrees and 0:17:21.800 --> 0:17:23.639 then it's going to shoot off a jet of gas 0:17:23.680 --> 0:17:26.840 like molten rock and and gas coming out of the asteroid, 0:17:26.920 --> 0:17:29.080 which is going to act like a little rocket, pushing 0:17:29.080 --> 0:17:31.240 it to the side. Right. So if you can heat 0:17:31.320 --> 0:17:33.640 up one side of the asteroid, you basically can push 0:17:33.680 --> 0:17:35.679 it off course, so you would aim it to the 0:17:35.720 --> 0:17:37.840 side of it, not directly at it. Yeah, I mean 0:17:37.880 --> 0:17:40.679 you're imagining like compu compue compute, Right, I'm shooting these 0:17:40.720 --> 0:17:43.679 things out of the sky direct hit. We're like, We're like, 0:17:46.000 --> 0:17:48.439 but we don't have we don't have powerful enough to 0:17:48.440 --> 0:17:51.080 blow them up, right. The key is to heat it 0:17:51.160 --> 0:17:53.639 up on one side. So you're saying laser technology has 0:17:53.680 --> 0:17:56.000 been improving all these years and now we can actually 0:17:56.040 --> 0:18:00.760 maybe build a death star rate. Yeah. Well, we can't 0:18:00.760 --> 0:18:04.040 blow up planets, right, um, so we can't make disturbances 0:18:04.040 --> 0:18:06.199 in the force like the way you maybe imagining, but 0:18:06.320 --> 0:18:09.199 we can shoot lasers at pretty far away objects and 0:18:09.240 --> 0:18:13.159 deposit significant energy. Um. And so the people have been 0:18:13.200 --> 0:18:15.680 doing studies and the best plan they have so far 0:18:15.760 --> 0:18:18.280 is to build a space based laser right. Right. You 0:18:18.320 --> 0:18:20.240 don't want to shoot the lasers from the ground because 0:18:20.240 --> 0:18:21.679 then they got to go through the atmosphere and they 0:18:21.720 --> 0:18:25.280 get defocused. So you have to have an orbiting platform 0:18:25.400 --> 0:18:29.400 of powerful lasers. Right. And if you're thinking laser gun, 0:18:29.960 --> 0:18:32.200 if you're thinking, yeah, that's not going to be misused 0:18:32.240 --> 0:18:36.040 by by some politicians space gun literally space gun? Yeah, 0:18:36.080 --> 0:18:37.239 I mean, do you want to build this and then 0:18:37.240 --> 0:18:39.159 put in the hands of the next president, whoever it's 0:18:39.200 --> 0:18:41.800 going to be, you know, over of Jay Z or 0:18:42.000 --> 0:18:43.919 Kid Rock or whoever is gonna be the next president. 0:18:45.640 --> 0:18:48.320 Make sure you can't point it back, you know, like exactly, 0:18:48.400 --> 0:18:51.080 it only works you pointed away from the Earth. Anyway, 0:18:51.119 --> 0:18:53.240 you gotta point it from space. You've gotta point it 0:18:53.240 --> 0:18:55.280 at the asteroid and you gotta hit it, and you 0:18:55.280 --> 0:18:57.160 gotta cook it for a little while. I mean, because 0:18:57.200 --> 0:18:58.960 by the time the laser gets there, it's going to 0:18:59.000 --> 0:19:02.000 be more diffuse, right, So you've got a deposit enough energy. 0:19:02.400 --> 0:19:05.640 So the studies that I read, they estimate that depending 0:19:05.640 --> 0:19:07.879 on the power of the laser, it could take between 0:19:07.880 --> 0:19:10.840 a year and ten years to push the asteroid off 0:19:10.840 --> 0:19:15.520 course for like a planet killer asteroid. Yeah, and so 0:19:15.600 --> 0:19:17.720 that's a long time, which means you've got to see 0:19:17.760 --> 0:19:21.520 this thing coming well in advance. And in our podcast 0:19:21.560 --> 0:19:23.639 we talked about how there isn't really a lot of 0:19:23.720 --> 0:19:26.119 danger from asteroids in our Solar system because the biggest 0:19:26.160 --> 0:19:27.840 ones we've seen, we know where they are, we know 0:19:27.960 --> 0:19:30.640 they're not coming for us. The real danger is from 0:19:30.720 --> 0:19:34.520 comets because they're big, they're fast, and we don't necessary 0:19:34.600 --> 0:19:37.760 we haven't necessarily seen their orbits, and we might just 0:19:37.840 --> 0:19:39.920 have like less than a year of warning. And they're 0:19:39.920 --> 0:19:41.960 they're supposed to be made of ice, right, Yeah, they're 0:19:42.160 --> 0:19:44.600 there's like a huge snowball, right, and that would be 0:19:44.600 --> 0:19:46.600 pretty dangerous and we have less than a year of warning, 0:19:47.240 --> 0:19:50.760 so that that's not terribly optimistic, right. The other plan 0:19:50.880 --> 0:19:53.520 is to launch the lasers and then send them to 0:19:53.760 --> 0:19:55.800 the asteroids so they can get closer up and then 0:19:55.840 --> 0:19:58.280 you can have smaller lasers. But you know, then you 0:19:58.320 --> 0:20:00.840 have to spend time getting them to the asteroid, and 0:20:01.200 --> 0:20:04.840 it gets pretty complicated where it's the laser itself. You 0:20:04.840 --> 0:20:06.800 shoot it from Earth would get there the speed of light. 0:20:06.920 --> 0:20:08.080