WEBVTT - Detecting Gravitational Waves 0:00:00.160 --> 0:00:07.160 Brought to you by Toyota. Let's go places. Welcome to 0:00:07.360 --> 0:00:15.360 Forward Thinking. Hey there, and welcome to Forward Thinking, the 0:00:15.440 --> 0:00:19.040 podcast that looks at the future and says white about 0:00:19.760 --> 0:00:23.160 I'm Jonathan Strickland, I'm Lauren voc Obama, and I'm Joe McCormick. 0:00:23.200 --> 0:00:25.439 And today, you guys aren't going to be able to 0:00:25.600 --> 0:00:27.920 depend on me to be my normal plucky self because 0:00:27.960 --> 0:00:30.120 I've got kind of a bad cold. So I'm sorry 0:00:30.120 --> 0:00:33.040 that I'm even talking in your general direction right now, 0:00:33.080 --> 0:00:35.440 but I suppose the show must go on. Well yeah, 0:00:35.479 --> 0:00:37.919 and Joe, it's it's kind of it's kind of fitting 0:00:38.120 --> 0:00:42.680 that that you are a little out of play here, 0:00:42.920 --> 0:00:46.640 right because we're going to revisit a topic that Lauren 0:00:46.680 --> 0:00:50.200 and I talked about, gravitational waves, and you weren't here 0:00:50.240 --> 0:00:52.559 for that episode. God, just act like I'm not here. 0:00:52.640 --> 0:00:55.080 So yeah, so mentally you're you're again not in the room. 0:00:56.800 --> 0:01:00.560 You're on vacation. You're always wonderful and find an excellent Yeah, 0:01:00.640 --> 0:01:03.440 I'm sure that you'll be a joy as always. But hey, 0:01:03.480 --> 0:01:07.840 gravitational waves, this was some big this month. Yeah, huge news. 0:01:07.920 --> 0:01:10.959 And actually it's funny because the discovery happened in two 0:01:11.000 --> 0:01:14.039 thousand and fifteen. But as is the case with any 0:01:14.120 --> 0:01:19.160 really you know, careful, responsible scientific inquiry, it took some 0:01:19.240 --> 0:01:23.560 time for scientists to verify the information the data they 0:01:23.600 --> 0:01:26.560 had gathered before they actually announced what they had found. 0:01:26.640 --> 0:01:28.560 You know, it did, but I don't know if you 0:01:28.640 --> 0:01:31.319 all noticed it, if you follow the the I don't know, 0:01:31.400 --> 0:01:36.240 science writers on Twitter or or the science press in general. 0:01:36.640 --> 0:01:41.600 There were several rounds of rumors flaring up where some 0:01:41.760 --> 0:01:45.240 prominent physicists or cosmologists would sort of like drop a 0:01:45.319 --> 0:01:49.400 hint saying like, I think they found gravity waves. Yeah, 0:01:49.400 --> 0:01:50.920 I know, you're gonna you're gonna get out of your 0:01:50.960 --> 0:01:53.800 red pin about that a little bit. Yeah, And and 0:01:53.840 --> 0:01:55.760 so somebody would print a story about that, and the 0:01:55.800 --> 0:01:58.200 rumor mill would flare up, and then it would all 0:01:58.280 --> 0:01:59.960 end with well, I guess we'll just have to wait 0:02:00.040 --> 0:02:02.600 until they announced their findings and see what happened. But 0:02:02.720 --> 0:02:05.880 it turned out that the rumors were in this case true, right. 0:02:05.920 --> 0:02:10.880 There was a very very strong, very well established piece 0:02:10.880 --> 0:02:14.120 of evidence for gravitational waves in the universe. Yes, a 0:02:14.600 --> 0:02:19.760 a detection that appears to be pretty much air tight. 0:02:20.400 --> 0:02:23.400 So uh, And that was announced on February eleven. We 0:02:23.400 --> 0:02:26.560 were all eagerly waiting for the announcement. In fact, many 0:02:26.600 --> 0:02:30.280 of us were following it live as it was happening. Joe, 0:02:30.360 --> 0:02:32.320 you were tweeting about it live as it was happening. 0:02:32.320 --> 0:02:35.240 As I recall, I think I just I retweeted. Some 0:02:35.320 --> 0:02:41.360 people got you. I wasn't. I wasn't live tweeting, and 0:02:41.520 --> 0:02:45.120 you were tweeting. You weren't undead? Are you undead? Is 0:02:45.120 --> 0:02:49.919 this what this called? Isomie a little bit undead? I 0:02:50.000 --> 0:02:52.600 hope you all both brought across well at any rate. 0:02:52.880 --> 0:02:56.359 The last zombies. Okay, go ahead if you if you're 0:02:56.400 --> 0:03:00.080 really cross with a zombie, they take note. So we 0:03:00.160 --> 0:03:03.400 originally talked about gravitational waves back in September two thousand 0:03:03.400 --> 0:03:07.480 and fourteen, and in that conversation we were talking specifically 0:03:07.520 --> 0:03:11.320 about BICEP two, which is a telescope that's in the Antarctic. Yeah, 0:03:11.360 --> 0:03:14.280 and if you remember some time vaguely in the past, 0:03:14.320 --> 0:03:17.440 either this podcast or just other general news announcements a 0:03:17.480 --> 0:03:19.480 few years ago, and you're saying, like, wait, I thought 0:03:19.480 --> 0:03:22.919 they already discovered gravitational waves. There is a reason you're 0:03:22.960 --> 0:03:26.040 remembering that. Yeah. Yeah, Well they said, hey, guys, I 0:03:26.080 --> 0:03:28.920 think that we we we think that we discovered gravitational waves. 0:03:28.960 --> 0:03:30.919 This is so great. And what they actually discovered was 0:03:31.000 --> 0:03:33.760 spacedest yeah, or at least space dust was enough of 0:03:33.800 --> 0:03:37.760 a factor to throw the results into serious doubt. But 0:03:38.000 --> 0:03:39.840 we'll talk about that a little bit more later in 0:03:39.840 --> 0:03:42.800 the podcast. This time, we're going to really be focusing 0:03:43.000 --> 0:03:47.480 on what Lego found. Uh Ligo is a pair of observatories, 0:03:47.640 --> 0:03:49.360 and we'll talk more about those in a minute. But 0:03:49.440 --> 0:03:52.040 before we get into any of that, perhaps it's best 0:03:52.080 --> 0:03:55.440 to actually take some time to talk about what gravitational 0:03:55.440 --> 0:03:59.160 waves are in the first place, and to understand that 0:03:59.200 --> 0:04:02.280 you've gotta look back in history, all the way back 0:04:02.320 --> 0:04:06.800 to nineteen sixteen, which is when Albert Einstein published his 0:04:06.800 --> 0:04:09.480 his theory of general relativity, had been working on it 0:04:09.520 --> 0:04:13.200 since nineteen o five. Right, So, Alfred B. Iimstein was 0:04:13.400 --> 0:04:16.880 out on a train one day, hurling axes out the 0:04:16.920 --> 0:04:20.240 window at passing herds of buffalo and he never give 0:04:20.279 --> 0:04:23.680 you cold medication before a podcast. And he noticed that 0:04:23.760 --> 0:04:26.880 as he tossed each ax, it arcd towards the ground 0:04:26.920 --> 0:04:30.000 instead of flying off in an infinite direction in which 0:04:30.000 --> 0:04:33.560 he threw it. So why does that happen. Alright, ignoring 0:04:33.600 --> 0:04:37.440 everything that Joe just said, Here's here's what Einstein was 0:04:37.440 --> 0:04:42.800 was considering. He had been really thinking hard about the 0:04:42.880 --> 0:04:47.640 nature of the universe. Uh. This was part mathematics, part philosophy, 0:04:48.120 --> 0:04:53.680 part just uh just using logic to its inevitable conclusion. 0:04:54.320 --> 0:04:57.840 And it was incredible. The theory he came up with, 0:04:57.920 --> 0:05:00.599 it was it was phenomenal, and not just phenomenal. But 0:05:01.120 --> 0:05:04.600 over the years, so much of that theory has proven 0:05:04.680 --> 0:05:08.680 to be accurate to what we see in reality. That 0:05:09.400 --> 0:05:12.520 you know, we we just keep on supporting the various 0:05:12.560 --> 0:05:15.279 predictions that were made, and gravitational waves were one of 0:05:15.320 --> 0:05:19.280 the predictions made in the theory of general relativity. Uh. 0:05:19.320 --> 0:05:23.320 He he had argued that that the universe is made 0:05:23.400 --> 0:05:27.560 up of uh space time continuum. You've probably heard that 0:05:27.600 --> 0:05:29.760 if you've ever watched any Star Trek, you've heard about 0:05:29.760 --> 0:05:32.880 the space time continuum. But the spacetime continuum is is 0:05:32.880 --> 0:05:36.480 sort of this idea of space and time together forming 0:05:36.520 --> 0:05:40.960 kind of a fabric of the universe and matter or 0:05:41.279 --> 0:05:43.760 to be really just just to to talk it in 0:05:43.760 --> 0:05:48.800 the terms he used, mass can change, can can warp spacetime. 0:05:48.839 --> 0:05:51.160 In fact, it does warp spacetime. The presence of matter 0:05:51.200 --> 0:05:56.960 warps spacetime. So the most common analogy that you tend 0:05:56.960 --> 0:06:00.159 to see is that imagine you've got a trampoline and 0:06:00.200 --> 0:06:02.680 you put a bowling ball on the trampoline. It ends 0:06:02.760 --> 0:06:05.760 up making a dimple in the trampoline. It sinks down 0:06:05.800 --> 0:06:09.120 where the bowling ball is resting that here here, the 0:06:09.200 --> 0:06:12.680 trampoline being spacetime and the bowling ball being say a star, 0:06:12.839 --> 0:06:16.120 yeah exactly, let's let's a star, black hole, anything that's 0:06:16.120 --> 0:06:19.960 got a lot of mass, and uh you that would 0:06:19.960 --> 0:06:23.360 show you how the trampoline warps around the bowling ball, 0:06:23.440 --> 0:06:26.800 like spacetime warps around an object of great mass. Keeping 0:06:26.800 --> 0:06:29.080 in mind, of course, that we're using more or less 0:06:29.080 --> 0:06:32.160 a two dimensional representation to talk about three dimensional concept. 0:06:32.600 --> 0:06:36.640 But it's really hard to imagine a three dimensional concept. Really, Yeah, 0:06:36.720 --> 0:06:38.880 that's true, because you're talking about time. It is true. 0:06:39.560 --> 0:06:42.039 But then if you were to take a marble, let's say, 0:06:42.120 --> 0:06:44.240 and roll it across the trampoline. Now, if it were 0:06:44.279 --> 0:06:46.240 if there were no bowling ball on it, the marble 0:06:46.279 --> 0:06:48.360 would just roll from one side to the other, assuming 0:06:48.360 --> 0:06:50.560 that you're on level ground and all that. But with 0:06:50.640 --> 0:06:53.839 the bowling ball. There, it's gonna start spiraling inward towards 0:06:53.880 --> 0:06:57.200 the bowling ball. And Einstein argued that what we see 0:06:57.240 --> 0:07:01.599 with gravity, with with gravitational pull between like a star 0:07:01.920 --> 0:07:05.599 and a planet, or even the center of a galaxy 0:07:05.720 --> 0:07:10.200 and all of the star systems, that's how they behave 0:07:10.920 --> 0:07:15.080 they move in that same spiral. And uh So, now 0:07:15.160 --> 0:07:17.200 one difference you might observe is that you think, hey, 0:07:17.240 --> 0:07:19.200 well if I did that on a trampoline, and probably 0:07:19.320 --> 0:07:21.600 marble would probably only spiral around the bowling ball three 0:07:21.680 --> 0:07:24.040 or four times before it crashed into it. There, I 0:07:24.040 --> 0:07:25.960 would guess the difference is going to be in this 0:07:26.000 --> 0:07:30.520 example friction between the marble and the trampoline. We also 0:07:30.640 --> 0:07:34.840 speak and orbits in space being you know, almost negligible 0:07:34.840 --> 0:07:38.280 amounts of friction. Yeah, that's definitely, that's definitely the case. 0:07:38.360 --> 0:07:41.600 It helps. So what we see here is that spacetime 0:07:41.680 --> 0:07:47.560 curves around objects and then be building upon that. Uh 0:07:47.640 --> 0:07:52.480 Einstein said, if you have a large mass undergo a 0:07:52.600 --> 0:07:56.240 violent change, either it changes shape or it changes its 0:07:56.280 --> 0:07:59.880 motion in some way in a dramatic way, it creates 0:08:00.000 --> 0:08:03.440 these ripples in space time that propagate outward at the 0:08:03.480 --> 0:08:08.000 speed of light. And these are gravitational waves. Um. So 0:08:08.360 --> 0:08:13.000 it's actual ripples in space time itself, and it's kind 0:08:13.000 --> 0:08:15.600 of like an electromagnetic wave, and that it moves at 0:08:15.640 --> 0:08:19.679 that speed of light, but unlike electromagnetic waves, it can't 0:08:19.720 --> 0:08:22.960 be absorbed and it can't be scattered. Yeah, it behaves 0:08:22.960 --> 0:08:25.320 in that way, more like a sound wave. Yeah, exactly. 0:08:25.320 --> 0:08:27.440 So if you think of sound waves, where when you 0:08:27.600 --> 0:08:30.600 hear a sound, what you're actually hearing is the motion 0:08:30.640 --> 0:08:34.559 of air molecules. Those air molecules are being compressed by 0:08:34.600 --> 0:08:38.600 an oncoming wave and then they expand again afterward. It's 0:08:38.720 --> 0:08:42.520 very similar to that, except we're talking about the fabric 0:08:42.640 --> 0:08:46.560 of reality itself. Now, let me play Jonathan for a 0:08:46.559 --> 0:08:49.000 second and be pedantic. It wouldn't necessarily have to be 0:08:49.080 --> 0:08:52.880 air molecules, would it be whatever medium that the sound 0:08:52.920 --> 0:08:55.199 is traveling through. That's true. Yeah, it could be solid 0:08:55.200 --> 0:09:00.360 wood and it's still has um and we should we 0:09:00.360 --> 0:09:04.400 should put in that Einstein himself wasn't entirely sure about 0:09:04.400 --> 0:09:07.360 this gravitational wave stuff. He kind of flip flopped on 0:09:07.440 --> 0:09:09.320 it a few times, but always came back around to 0:09:09.320 --> 0:09:12.559 support it. So I think that he himself would be 0:09:12.640 --> 0:09:14.560 sort of tickled that we a came up with a 0:09:14.559 --> 0:09:17.280 way to detect them and be have actually detected Yeah. 0:09:17.280 --> 0:09:20.520 I think he would be flabber guested because I the 0:09:20.559 --> 0:09:25.120 impression I get is that Einstein was fairly certain because 0:09:25.200 --> 0:09:28.520 the nature of gravitational waves, they would be undetectable. There 0:09:28.720 --> 0:09:31.240 there'll be no way to directly observe them because they 0:09:31.240 --> 0:09:36.040 are invisible, there's nothing. They're not like electromagnetic radiation, where 0:09:36.559 --> 0:09:40.600 you've got an actual visible spectrum. Um. So I think 0:09:40.679 --> 0:09:42.800 that would have really shocked him that we had come 0:09:42.880 --> 0:09:46.800 up with a really clever way of detecting the presence 0:09:46.800 --> 0:09:49.840 of gravitational waves. Now, Jonathan, why is it that you 0:09:49.880 --> 0:09:51.880 have a bone to pick with anybody who calls this 0:09:51.960 --> 0:09:55.880 most recent discovery the discovery of gravity waves? Well, because 0:09:55.880 --> 0:09:59.200 it's wrong. So gravity waves you told me all about 0:09:59.240 --> 0:10:03.320 the wrongness. Gravity and gravitational are two different things. With 0:10:03.400 --> 0:10:05.760 a gravitational wave, you are talking about this ripple through 0:10:05.760 --> 0:10:08.559 space time that travels outward at the speed of light. 0:10:09.040 --> 0:10:12.000 With gravity waves, you're talking about a wave that exists 0:10:12.160 --> 0:10:14.760 due to gravity. It's something that you would find on 0:10:14.800 --> 0:10:17.760 a planet, either in some sort of fluid system, whether 0:10:17.800 --> 0:10:22.680 it's an atmosphere or like a body of water. So, um, 0:10:22.880 --> 0:10:26.120 let's say you've got an ocean and you've got wind 0:10:26.160 --> 0:10:28.600 blowing across the surface of that ocean, it starts to 0:10:29.320 --> 0:10:33.400 disturb the water. Gravity is pulling down on the surface 0:10:33.600 --> 0:10:38.120 of that water, and uh, waters buoyancy is acting in 0:10:38.640 --> 0:10:43.480 opposition to gravity, and that combined with the wind, creates 0:10:43.640 --> 0:10:48.280 a wind driven um wave. That would be a gravity wave. 0:10:48.679 --> 0:10:51.280 It's a wave that exists because gravity is there. If 0:10:51.320 --> 0:10:53.160 there were no gravity through would even be a body 0:10:53.200 --> 0:10:57.000 of water there. Uh. That is a gravity wave totally 0:10:57.040 --> 0:11:00.640 different from a gravitational wave, just a physical wave that 0:11:00.760 --> 0:11:04.760 you can observe through some form of fluidic system. And 0:11:04.840 --> 0:11:07.680 so if you ever hear someone say gravity waves of 0:11:07.679 --> 0:11:11.920 gravitational wave as a matter of shorthand they're technically being incorrect, 0:11:11.960 --> 0:11:15.680 you should probably find a polite way to say, maybe 0:11:15.720 --> 0:11:18.960 you meant gravitational wave, or you could be like me, 0:11:19.040 --> 0:11:23.200 and there's no polite way to say that. Yeah, I 0:11:23.240 --> 0:11:26.200 gave up on being polite years ago, so I just 0:11:26.200 --> 0:11:28.000 tried to caution other people not to make the same 0:11:28.080 --> 0:11:32.200 choices I made. Um. But yeah, there's some some other 0:11:32.240 --> 0:11:36.959 interesting things about gravitational waves. They pass through stuff. So 0:11:37.320 --> 0:11:40.559 like we said, yeah, yeah, they don't act like electromagnetic waves. Yeah, 0:11:40.600 --> 0:11:42.840 they don't get absorbed or reflected, so they just poop 0:11:42.920 --> 0:11:45.440 keep on going. So if you've got, for example, a 0:11:45.480 --> 0:11:50.000 planet between you and electromagnetic radiation such as light from 0:11:50.040 --> 0:11:53.280 the Sun, you will experience in eclipse because the planet 0:11:53.320 --> 0:11:57.920 blocks it. But it will not block these gravity waves exactly, won't. 0:11:57.960 --> 0:12:01.560 It won't eclipse the the movement of waves toward you. 0:12:01.800 --> 0:12:04.679 The waves will get weaker as they propagate out over 0:12:04.720 --> 0:12:08.000 distance though, yes, and uh So if you're talking about 0:12:08.040 --> 0:12:11.720 a gravitational wave that has you know, has happened because 0:12:11.760 --> 0:12:15.920 of some massive event that's a billion light years away, 0:12:15.960 --> 0:12:18.280 they are very very faint by the time they get 0:12:18.280 --> 0:12:23.600 to Earth. Uh And that also leads to why they've 0:12:23.640 --> 0:12:26.200 been so tricky to detect. Not only are they invisible, 0:12:26.240 --> 0:12:30.280 but they're not very strong. So we have to look 0:12:30.320 --> 0:12:33.160 for gravitational waves that have been caused by really really 0:12:33.200 --> 0:12:35.520 big events, like in the case of the one that 0:12:35.640 --> 0:12:39.960 Ligo detected in September two thousand fifteen, it was the 0:12:40.080 --> 0:12:43.080 collision of two black holes. It's a pretty big event. 0:12:43.720 --> 0:12:46.720 Others could be two neutron stars that are orbiting one 0:12:46.760 --> 0:12:50.520 another rapidly, which would create kind of an oscillating and 0:12:50.600 --> 0:12:55.640 continuous a series of gravitational waves. Um or it could 0:12:55.679 --> 0:12:59.280 be like a supernova exploding that to do it. A 0:12:59.280 --> 0:13:01.920 big bang that would do it too. In fact, that 0:13:02.000 --> 0:13:04.360 was what my step two was looking for, was the 0:13:04.520 --> 0:13:07.800 evidence of gravity waves from the era of the Big Bang. 0:13:07.880 --> 0:13:13.880 I just caught you in it. What, oh man, I 0:13:13.360 --> 0:13:18.640 I I stand correct, I sit corrected here in to eat, 0:13:18.840 --> 0:13:21.520 Thank you well, and as soon as I get the 0:13:21.520 --> 0:13:23.400 foot out of my mouth, I will start chewing upon 0:13:23.440 --> 0:13:27.880 the hat. Yes, gravitational wave not gravity wave. No, it's 0:13:27.920 --> 0:13:30.079 true that they have been so difficult to detect and 0:13:30.240 --> 0:13:33.959 that we've had to come up with very interesting methods 0:13:34.000 --> 0:13:39.400 of trying to detect them, involving laser interferometry. Yeah. So 0:13:39.520 --> 0:13:43.680 here's here's something that's really cool about a gravitational wave 0:13:44.240 --> 0:13:47.000 because it's this ripple in space time. It actually is 0:13:47.040 --> 0:13:48.560 a small you can think of it like a small 0:13:48.640 --> 0:13:53.360 fold in spacetime, right, and that means it can actually 0:13:53.559 --> 0:13:57.920 change the distance between two points by compressing that distance 0:13:58.480 --> 0:14:01.880 or expanding it like a rubber band. So you've got 0:14:01.880 --> 0:14:05.000 like a piece of elastic h or if you prefer, 0:14:05.120 --> 0:14:07.800 you know, just just imagine that, Um, Joe, you and 0:14:07.840 --> 0:14:10.800 I are standing across a football field from one another. 0:14:11.160 --> 0:14:13.360 You're on one end zone. I'm in the other end zone. 0:14:14.000 --> 0:14:16.640 Their en zones in football, right, I'm just looking for 0:14:17.280 --> 0:14:21.040 There's no help from the one with the oblong spheroid, right, Yes, 0:14:21.080 --> 0:14:24.240 that's it. Or you know, a soccer field if you prefer, 0:14:24.320 --> 0:14:27.800 But then you know where at either end gravitational wave 0:14:27.840 --> 0:14:30.960 passes through. Let's say it's a massive gravitational wave, something 0:14:31.120 --> 0:14:34.120 way bigger than we would ever actually observe here on Earth. 0:14:34.560 --> 0:14:37.640 What would appear to happen is that Joe and I 0:14:37.680 --> 0:14:40.080 from our perspectives, it would look like we got closer 0:14:40.120 --> 0:14:42.800 and then further apart, and then closer and then further apart, 0:14:43.240 --> 0:14:47.280 without ever taking a step in either direction. That the are, 0:14:47.520 --> 0:14:52.680 the world itself has compressed and expanded around us because 0:14:52.720 --> 0:14:56.680 of this fold in spacetime that's passing through, which sounds 0:14:56.720 --> 0:15:02.080 like some serious like matrix style stuff. But either fortunately 0:15:02.160 --> 0:15:05.600 or unfortunately, depending on how you know, stable you like 0:15:05.680 --> 0:15:10.240 your reality, that's that's that kind of dramatic change is 0:15:10.280 --> 0:15:13.360 not what we observe from gravitational waves, right, Not at all, 0:15:13.480 --> 0:15:16.840 not even remotely in the same football field as it were. 0:15:17.720 --> 0:15:20.200 Uh No, Instead, if you were to have something like 0:15:20.280 --> 0:15:24.880 a supernova explosion, and I should say an asymmetric supernova 0:15:24.960 --> 0:15:28.720 explosion for reasons I don't understand, a symmetrical supernova does 0:15:28.760 --> 0:15:33.280 not a supernova explosion does not generate gravitational waves. I 0:15:33.360 --> 0:15:36.160 don't know why I was reading it trying to find 0:15:36.160 --> 0:15:37.840 more information, but it got to a point where the 0:15:37.880 --> 0:15:42.440 astrophysics got way too complicated for me to understand. However, 0:15:42.480 --> 0:15:44.240 what I do understand is that if there were a 0:15:44.240 --> 0:15:47.840 supernova explosion in our galaxy in the Milky Way, the 0:15:47.880 --> 0:15:52.200 gravitational waves generated from that would only be powerful enough 0:15:52.320 --> 0:15:55.880 to change the distance between Earth and the Sun by 0:15:55.880 --> 0:15:58.640 the diameter of one hydrogen atom. That's how much it 0:15:58.640 --> 0:16:04.640 would oscillate. Oh yeah, okay, you probably would notice. So 0:16:04.800 --> 0:16:06.520 this is like a princess and the p kind of thing, 0:16:06.560 --> 0:16:12.000 isn't it. Yeah, definitely, definitely on that level. Obviously, we 0:16:12.040 --> 0:16:16.520 need to build a more sensitive princess. That's that's the 0:16:16.840 --> 0:16:20.400 you know, that's entirely the plot. Yeah, yeah, we're about 0:16:20.400 --> 0:16:24.120 a mattress. You know, it's all musical about that. Oh 0:16:24.280 --> 0:16:30.800 I didn't build a robot princess, any number of mattress. 0:16:30.920 --> 0:16:35.560 They just they just uh collued to make her uncomfortable 0:16:35.600 --> 0:16:39.760 so that she she complains about the the lumpiness of 0:16:39.760 --> 0:16:41.360 the mattress, and it turns out that there's not just 0:16:41.400 --> 0:16:43.400 a p under there. There's also a suit of armor 0:16:43.400 --> 0:16:46.640 and a shield. Spoiler alert for any of you who 0:16:46.680 --> 0:16:49.040 are really looking forward to what's upon a mattress. Yeah. 0:16:49.080 --> 0:16:50.640 But but but I suppose they did kind of create 0:16:50.720 --> 0:16:53.000 like a laser princess. So yeah, but we'll get into that. 0:16:53.040 --> 0:16:56.480 So anyway, So so I just mentioned that if you're 0:16:56.520 --> 0:16:59.640 looking at the Earth and the Sun, you're talking about 0:16:59.640 --> 0:17:02.600 the differ prints of the diameter of an hydrogen atom 0:17:02.880 --> 0:17:06.600 in the distance, which is incredible to think about. But 0:17:07.040 --> 0:17:11.120 that that change, that difference in distance gets smaller as 0:17:11.160 --> 0:17:14.600 you get two smaller scales. So let's talk about if 0:17:14.640 --> 0:17:16.960 you were on Earth and trying to measure this, because 0:17:16.960 --> 0:17:20.439 this gets to why it has been so challenging to 0:17:20.520 --> 0:17:23.520 detect gravitational waves here on Earth. Okay, don't use a 0:17:23.520 --> 0:17:27.080 football field analogy. What about the need to how about 0:17:27.080 --> 0:17:29.560 the beginning and end of the line for space Mountain. 0:17:31.280 --> 0:17:33.879 That's a queue that goes like, yeah, that one already 0:17:33.920 --> 0:17:36.400 loops around back on itself in weird ways. Yeah, it's 0:17:36.440 --> 0:17:38.800 not really gonna work. No, I don't need to make 0:17:38.800 --> 0:17:42.240 that comparison. I was just to to establish the weirdness 0:17:42.400 --> 0:17:45.160 of what happens. But no, I wanted to just talk 0:17:45.200 --> 0:17:47.920 about the scale. So if you were talking about here 0:17:47.960 --> 0:17:51.760 on Earth and you're trying to measure that that change 0:17:51.840 --> 0:17:56.040 in reality, that change in distance because the spacetime continuum 0:17:56.119 --> 0:17:58.720 is being folded in this ripple. Uh. If you had 0:17:58.720 --> 0:18:00.600 two objects that are about a column butt are apart, 0:18:01.080 --> 0:18:04.199 the change in distance they would experience due to that 0:18:04.280 --> 0:18:09.040 gravitational wave would be thousands of the diameter of a proton. 0:18:09.840 --> 0:18:13.159 So take a sub atomic particle and go a teeny 0:18:13.200 --> 0:18:16.240 tiny fraction of the diameter of that subotomic particle, and 0:18:16.280 --> 0:18:20.480 that's how much difference in distance it would experience. Get 0:18:20.680 --> 0:18:23.800 out your your proton knife and your proton measuring set, 0:18:24.000 --> 0:18:26.720 and it turns out your ruler is not going to 0:18:26.800 --> 0:18:30.360 be terribly helpful in that case. So that is one 0:18:30.359 --> 0:18:33.720 of the reasons why it's been so incredibly challenging to 0:18:33.880 --> 0:18:37.640 detect the presence of a gravitational wave. And and we 0:18:37.640 --> 0:18:40.399 we've had a few leads, or if you prefer, a 0:18:40.400 --> 0:18:43.840 few false starts in detecting them throughout history. Back in 0:18:44.000 --> 0:18:48.200 nineteen sixty nine, University of Maryland physicist Joseph Weber created 0:18:48.240 --> 0:18:51.840 this this six foot aluminum cylinder that he claimed would 0:18:51.880 --> 0:18:55.320 act like an antenna for gravitational waves. He said that 0:18:55.400 --> 0:18:57.640 when such a wave hit the cylinder, it would ring 0:18:57.760 --> 0:19:01.280 like a tuning fork, but nobody else could replicate his results. 0:19:01.359 --> 0:19:03.680 It was a kind of neat looking device, though. There's 0:19:03.720 --> 0:19:05.679 actual video of this, and it look kind of like 0:19:05.720 --> 0:19:09.399 a mirrored two inside another tube, like there was like 0:19:09.440 --> 0:19:13.840 some sort of crazy physics disco going on inside there. Uh, 0:19:14.520 --> 0:19:16.720 or at least that's what I like to think. Back 0:19:16.720 --> 0:19:19.280 in nineteen seventy four, there are a pair of scientists 0:19:19.680 --> 0:19:25.879 in Puerto Rico who saw a binary pulsar system and 0:19:26.359 --> 0:19:29.520 they looked at the theory of general relativity, which predicted 0:19:29.560 --> 0:19:33.119 that such a system would gradually lose energy due to 0:19:33.280 --> 0:19:36.720 the too emitting gravitational waves. Some of its energy would 0:19:36.800 --> 0:19:40.720 go into creating these gravitational waves, and because you have 0:19:40.760 --> 0:19:43.400 a system losing energy, it would start to lose speed. 0:19:44.160 --> 0:19:47.960 And so they said, well, based upon this prediction, we 0:19:48.000 --> 0:19:51.159 should observe this change in speed as long as we 0:19:51.280 --> 0:19:55.040 keep an eye on this binary pulsar system. So they 0:19:55.119 --> 0:19:58.200 tracked it for eight years. At the end of the 0:19:58.280 --> 0:20:02.040 eight year period, they said the behavior of the binary 0:20:02.080 --> 0:20:06.440 pulsar system was completely in line with the predictions from 0:20:06.440 --> 0:20:11.159 general relativity. He said, it is behaving precisely the way 0:20:11.280 --> 0:20:15.160 it would if, in fact, gravitational waves are reality. Therefore, 0:20:15.680 --> 0:20:19.000 this is in support of gravitational waves. And even since then, 0:20:19.640 --> 0:20:23.199 over the forty years of observations that have happened with 0:20:23.280 --> 0:20:27.639 this binary pulsar system, those predictions continued to be supported. 0:20:28.040 --> 0:20:33.760 So that was great, you know, indirect evidence of gravitational waves, saying, well, 0:20:33.800 --> 0:20:37.320 if they don't exist, something else must be happening for 0:20:37.480 --> 0:20:39.600 this system to slow down the way it is. But 0:20:39.680 --> 0:20:42.160 the thing that makes most sense is that Einstein was right. 0:20:42.920 --> 0:20:45.560 Then we move ahead quite a bit. Let's talk about 0:20:45.600 --> 0:20:48.639 BICEP two. Now, BICEP two was going a different way 0:20:49.240 --> 0:20:52.520 about looking for gravitational waves. They were specifically looking for 0:20:52.600 --> 0:20:58.080 evidence of UH that would support a hypothesis called cosmic inflation, 0:20:58.840 --> 0:21:02.359 and inflation is a big deal in physical cosmology today. 0:21:02.400 --> 0:21:07.399 This is I think most physical cosmologists look at inflation 0:21:07.520 --> 0:21:11.000 is very promising theory. Yeah, And the whole reason why 0:21:11.119 --> 0:21:13.800 we have this this idea in the first place is 0:21:13.840 --> 0:21:17.600 to explain why the universe appears the way it does, 0:21:18.280 --> 0:21:22.320 while also trying to reconcile that with the Big Bang theory. 0:21:22.400 --> 0:21:25.359 Because I'm not going to get too far into the 0:21:25.359 --> 0:21:32.399 weeds here, but the basically the hypothesis says that about 0:21:32.520 --> 0:21:37.639 ten to the negative thirty six seconds. So take a 0:21:37.720 --> 0:21:40.840 ten and then take a decimal point and move that 0:21:41.119 --> 0:21:43.919 thirty six places to the left. Get get that proton 0:21:44.000 --> 0:21:47.000 knife out again, did up a second, right, That's that's 0:21:47.040 --> 0:21:49.480 where you get down to the teeny tiny, tiny tiny 0:21:49.480 --> 0:21:52.040 fraction of a second to about ten to the negative 0:21:52.080 --> 0:21:57.119 thirty three or thirty second power seconds. So so in 0:21:57.200 --> 0:22:01.760 an instant, as far as we're concerned, into an instant, Yeah, 0:22:02.000 --> 0:22:06.240 that at that moment, that's when the universe underwent rapid expansion, 0:22:07.320 --> 0:22:12.159 far greater than the rate of expansion it currently is 0:22:12.200 --> 0:22:15.960 going through. And it's expanding fast today. Yeah. Actually, then 0:22:15.960 --> 0:22:18.159 it's picking up speed, which is a little uh, at 0:22:18.240 --> 0:22:20.600 least according to our measurements, it is picking up speed. 0:22:20.640 --> 0:22:23.719 But that's that's something that we hope gravitational waves will 0:22:23.760 --> 0:22:26.440 help us learn more about in the future at any rate. 0:22:26.560 --> 0:22:30.080 A scientist named Alan Gooth proposed a hypothesis to explain 0:22:31.200 --> 0:22:34.560 why the universe looks the way it does and stay 0:22:34.640 --> 0:22:36.800 in line with the Big Bang theory. It was kind 0:22:36.840 --> 0:22:39.800 of like, well, in order for us to be where 0:22:39.840 --> 0:22:43.520 we are now based upon the observations of the universe 0:22:43.560 --> 0:22:45.760 we have made so far, and in order for the 0:22:45.760 --> 0:22:48.760 Big Bang theory to make any sense whatsoever, there had 0:22:48.800 --> 0:22:51.480 to be this period of cosmic inflation or else. It 0:22:51.560 --> 0:22:54.560 just doesn't work out. The math doesn't work out. And 0:22:55.119 --> 0:22:57.119 in a way you could argue, all this is almost 0:22:57.160 --> 0:22:59.800 like a placeholder, except again, it's kind of like Einstein. 0:23:00.119 --> 0:23:02.960 It's using logic saying, well, we we know about this, 0:23:03.359 --> 0:23:06.080 we're pretty sure about this other thing. But in order 0:23:06.119 --> 0:23:08.720 for those two things to reconcile, this other, this third 0:23:08.720 --> 0:23:11.840 thing must have happened at some point. Yeah. Yeah, it's 0:23:11.840 --> 0:23:15.880 theoretically solving for X in this equation. Yeah, and if 0:23:15.880 --> 0:23:19.960 you fast forward three thousand years after the Big Bang, 0:23:20.800 --> 0:23:23.960 you then have the emergence of the cosmic microwave background 0:23:24.119 --> 0:23:27.720 or c MB. Now, this is a radiation that's sort 0:23:27.760 --> 0:23:31.119 of a fingerprint left over from the from the era 0:23:31.240 --> 0:23:33.840 after the Big Bang. It's from it's when the universe 0:23:33.920 --> 0:23:37.080