1 00:00:04,800 --> 00:00:14,840 Speaker 1: With Technology Stuff. Hey there, and welcome to tex Stuff. 2 00:00:14,880 --> 00:00:18,239 Speaker 1: I'm your host, Jonathan Strickland, and today I wanted to 3 00:00:18,280 --> 00:00:21,800 Speaker 1: talk about something that was in the news recently, at 4 00:00:21,840 --> 00:00:26,560 Speaker 1: least recently when I'm recording this episode. On February eleven, sixteen, 5 00:00:26,720 --> 00:00:29,280 Speaker 1: that was, of course, the day when we got the 6 00:00:29,360 --> 00:00:33,960 Speaker 1: confirmation from a collaboration of scientists that in fact, the 7 00:00:34,040 --> 00:00:38,800 Speaker 1: Ligo Observatory had picked up a gravitational wave. And this 8 00:00:38,880 --> 00:00:43,000 Speaker 1: was huge news around the world. And in case you 9 00:00:43,040 --> 00:00:45,720 Speaker 1: were wondering, what the heck is this news all about? 10 00:00:45,840 --> 00:00:49,040 Speaker 1: How did they pick up that gravitational wave? What what 11 00:00:49,200 --> 00:00:54,080 Speaker 1: exactly is the technology powering our sensors to detect this stuff? 12 00:00:54,760 --> 00:00:56,480 Speaker 1: How does it all work? That's what this episode is 13 00:00:56,520 --> 00:00:59,920 Speaker 1: all about. So this was the very first time anyone 14 00:01:00,000 --> 00:01:03,680 Speaker 1: had been able to measure a gravitational wave directly. So 15 00:01:03,800 --> 00:01:07,440 Speaker 1: today we're gonna talk all about what that means and 16 00:01:07,480 --> 00:01:11,000 Speaker 1: how it happened. Now, to begin with, we need to 17 00:01:11,080 --> 00:01:14,600 Speaker 1: lay some groundwork and to to really get an understanding 18 00:01:14,680 --> 00:01:20,160 Speaker 1: what gravitational waves are. So gravitational waves, ultimately, we're one 19 00:01:20,160 --> 00:01:25,080 Speaker 1: of the predictions made by a certain Albert Einstein with 20 00:01:25,160 --> 00:01:29,040 Speaker 1: his theory of general relativity. So in that theory, Einstein 21 00:01:29,080 --> 00:01:34,039 Speaker 1: presented this idea that our universe is filled with spacetime. 22 00:01:34,480 --> 00:01:37,840 Speaker 1: If you're a fan of science fiction, you have undoubtedly 23 00:01:37,959 --> 00:01:41,120 Speaker 1: come across that term star trek is all about the 24 00:01:41,160 --> 00:01:43,560 Speaker 1: spacetime continuum, and that you've got to be careful. You 25 00:01:43,560 --> 00:01:46,199 Speaker 1: could rip a hole in the fabric of space time. 26 00:01:47,120 --> 00:01:50,480 Speaker 1: As far as we know, that's not really that possible. Um. 27 00:01:50,520 --> 00:01:53,200 Speaker 1: I mean, black holes could sort of be that maybe, 28 00:01:53,320 --> 00:01:58,880 Speaker 1: But at any rate, spacetime itself is this calling it 29 00:01:58,960 --> 00:02:00,920 Speaker 1: stuff is probably the wrong way of putting it, but 30 00:02:01,320 --> 00:02:05,560 Speaker 1: it is like a fabric and mass hangs inside this fabric. 31 00:02:06,280 --> 00:02:09,400 Speaker 1: And by mass, i'm talking about stuff like stars or 32 00:02:09,440 --> 00:02:14,440 Speaker 1: even an entire solar systems or galaxies that hang in 33 00:02:14,760 --> 00:02:18,080 Speaker 1: this fabric, and just like you would see in a 34 00:02:18,160 --> 00:02:22,720 Speaker 1: two dimensional display, Uh, it ends up curving the fabric 35 00:02:22,919 --> 00:02:27,760 Speaker 1: around the mass. Uh. We often talk about this in 36 00:02:27,919 --> 00:02:32,480 Speaker 1: terms of a very simple example that's easy to imagine. Uh. 37 00:02:32,720 --> 00:02:35,280 Speaker 1: You get some sort of stretchy material. Often you'll just 38 00:02:35,320 --> 00:02:38,359 Speaker 1: hear someone say, Okay, get a trampoline. You've got a trampoline, 39 00:02:39,160 --> 00:02:43,280 Speaker 1: and you put a big, heavy bowling ball on the trampoline, 40 00:02:43,560 --> 00:02:47,040 Speaker 1: so that bowling ball is going to deform the trampoline surface. 41 00:02:47,240 --> 00:02:49,880 Speaker 1: It's no longer going to be straight. It's going to 42 00:02:49,960 --> 00:02:52,720 Speaker 1: end up curving around the bowling ball to some extent, 43 00:02:52,800 --> 00:02:55,880 Speaker 1: creating kind of a dimple where the bowling ball has 44 00:02:56,000 --> 00:02:59,720 Speaker 1: has created this impression inside the trampoline, and as long 45 00:02:59,760 --> 00:03:02,400 Speaker 1: as the bowling ball is there, that impression is going 46 00:03:02,440 --> 00:03:05,400 Speaker 1: to stay. This is sort of the like the way 47 00:03:05,480 --> 00:03:10,760 Speaker 1: spacetime curves around giant masses like stars and and black 48 00:03:10,800 --> 00:03:14,360 Speaker 1: holes things like that. Of course, we have to remember 49 00:03:14,400 --> 00:03:17,960 Speaker 1: that spacetime is actually four dimensional, not a two dimensional 50 00:03:18,040 --> 00:03:20,360 Speaker 1: thing like a trampoline. I mean, I know that trampolines 51 00:03:20,400 --> 00:03:23,760 Speaker 1: technically have three dimensions, but we're really looking at a surface, 52 00:03:23,840 --> 00:03:27,120 Speaker 1: so it's more like a two dimensional plane in reality. 53 00:03:27,200 --> 00:03:30,000 Speaker 1: In spacetime it's four dimensional because you've got the three 54 00:03:30,320 --> 00:03:34,400 Speaker 1: spatial dimensions plus time, and that is a little difficult 55 00:03:34,440 --> 00:03:37,560 Speaker 1: to get your head around. But that's why we tend 56 00:03:37,600 --> 00:03:39,760 Speaker 1: to look at this two dimensional example. It's a lot 57 00:03:39,760 --> 00:03:43,480 Speaker 1: easier for us to imagine. So let's go a little 58 00:03:43,520 --> 00:03:46,520 Speaker 1: further with that analogy to kind of talk about gravity. See, 59 00:03:46,560 --> 00:03:49,760 Speaker 1: Einstein proposed that gravity was a manifestation of this curved 60 00:03:49,840 --> 00:03:53,640 Speaker 1: space time. And if we take that trampoline example. Let's 61 00:03:53,640 --> 00:03:55,840 Speaker 1: say that you have a regular trampoline. You haven't put 62 00:03:55,840 --> 00:03:57,920 Speaker 1: the bowling ball on there yet, so it's a nice 63 00:03:57,920 --> 00:04:00,520 Speaker 1: flat surface, and you have a marble, and you roll 64 00:04:00,600 --> 00:04:03,040 Speaker 1: the marble across the surface of the trampoline. So if 65 00:04:03,040 --> 00:04:05,440 Speaker 1: there's nothing else there, and if the trampoline is level, 66 00:04:05,520 --> 00:04:09,080 Speaker 1: if the surfaces level, the marble should just roll in 67 00:04:09,120 --> 00:04:11,240 Speaker 1: the straight line from one side of the trampoline to 68 00:04:11,240 --> 00:04:14,520 Speaker 1: the other. No problem. Now let's say you put that big, 69 00:04:14,560 --> 00:04:17,080 Speaker 1: heavy bowling ball on the trampoline. It creates that dimple, 70 00:04:17,520 --> 00:04:19,680 Speaker 1: and then you try and roll the marble across the 71 00:04:19,680 --> 00:04:23,640 Speaker 1: trampoline surface. Well, now that dimple is going to end 72 00:04:23,720 --> 00:04:26,120 Speaker 1: up affecting the pathway of the marble. It's going to 73 00:04:26,160 --> 00:04:31,040 Speaker 1: start to spiral inward toward the bowling ball. Ultimately it'll 74 00:04:31,120 --> 00:04:34,720 Speaker 1: end up making contact with the bowling ball. And Einstein said, 75 00:04:34,760 --> 00:04:37,960 Speaker 1: that's essentially what gravity is. It's that you've got these 76 00:04:38,600 --> 00:04:43,440 Speaker 1: large masses that curves spacetime to the extent that smaller 77 00:04:43,480 --> 00:04:47,720 Speaker 1: masses are spiraling inward toward the large mass. It's just 78 00:04:47,760 --> 00:04:50,800 Speaker 1: happening on a scale that's much, much, much larger than 79 00:04:50,839 --> 00:04:55,840 Speaker 1: any bowling ball marble example, But that this isn't essentially 80 00:04:55,920 --> 00:04:59,440 Speaker 1: what we see when we see planets orbiting a sun, 81 00:04:59,839 --> 00:05:02,960 Speaker 1: or or we see a moon orbiting a planet, or 82 00:05:03,040 --> 00:05:06,400 Speaker 1: we see star systems orbiting a galaxy, you know, the 83 00:05:06,400 --> 00:05:10,560 Speaker 1: center of a galaxy. And uh, it's all because of 84 00:05:10,640 --> 00:05:14,039 Speaker 1: this curved spacetime. Now, all of that already is pretty 85 00:05:14,080 --> 00:05:16,320 Speaker 1: heavy stuff. And keep in mind, there was not really 86 00:05:16,360 --> 00:05:21,960 Speaker 1: any way to directly observe this. It was mostly the 87 00:05:21,960 --> 00:05:27,080 Speaker 1: the just just Einstein using logic to work all this 88 00:05:27,160 --> 00:05:33,280 Speaker 1: out and math, logic and math, and ultimately it fit 89 00:05:33,400 --> 00:05:36,000 Speaker 1: with what we saw of the universe. But we weren't 90 00:05:36,000 --> 00:05:38,240 Speaker 1: able to test a lot of this. But then it 91 00:05:38,279 --> 00:05:41,800 Speaker 1: gets even more mind blowing because now we have to 92 00:05:41,800 --> 00:05:45,479 Speaker 1: get to gravitational waves. So Einstein said that if a 93 00:05:45,520 --> 00:05:50,240 Speaker 1: mass were large enough and either changed shape rapidly enough, 94 00:05:50,400 --> 00:05:54,120 Speaker 1: or it changed its movement in some way, uh really 95 00:05:54,160 --> 00:05:57,160 Speaker 1: really quickly, it would cause ripples of space time to 96 00:05:57,240 --> 00:06:01,640 Speaker 1: move outward from that event at the speed of light. 97 00:06:02,240 --> 00:06:05,200 Speaker 1: And those ripples are what we call gravitational waves, which 98 00:06:05,200 --> 00:06:08,200 Speaker 1: are different from gravity waves. By the way, I have 99 00:06:08,279 --> 00:06:11,640 Speaker 1: been known to accidentally say gravity waves instead of gravitational waves, 100 00:06:11,680 --> 00:06:14,440 Speaker 1: but the two are different things. A gravity wave is 101 00:06:14,440 --> 00:06:18,599 Speaker 1: a wave that exists because of gravity. In other words, 102 00:06:18,600 --> 00:06:21,080 Speaker 1: it's a physical wave of some sort of fluid system, 103 00:06:21,120 --> 00:06:25,719 Speaker 1: whether it's atmosphere or or water or some other liquid. Uh. 104 00:06:25,760 --> 00:06:28,520 Speaker 1: That's a gravity wave on a planet's surface. It's not 105 00:06:28,600 --> 00:06:30,760 Speaker 1: the same thing as a gravitational wave, which is really 106 00:06:30,800 --> 00:06:34,160 Speaker 1: a ripple of spacetime, and like I said, it moves 107 00:06:34,160 --> 00:06:36,840 Speaker 1: outward from that event at the speed of light um 108 00:06:36,920 --> 00:06:40,640 Speaker 1: And stuff that could cause significant gravitational waves, things that 109 00:06:40,680 --> 00:06:43,400 Speaker 1: would be big enough for us to potentially pick up 110 00:06:43,400 --> 00:06:45,880 Speaker 1: here on Earth if we had the right equipment, would 111 00:06:45,880 --> 00:06:48,880 Speaker 1: include things like two black holes orbiting or colliding with 112 00:06:48,880 --> 00:06:52,560 Speaker 1: one another, which in fact, that was the event that 113 00:06:52,640 --> 00:06:56,640 Speaker 1: we were able to pick up with the Ligo facilities. 114 00:06:56,720 --> 00:06:59,840 Speaker 1: And I'll talk about those in just a bit. But 115 00:07:00,040 --> 00:07:02,599 Speaker 1: there could be other stuff too, like neutron stars orbiting 116 00:07:02,640 --> 00:07:07,520 Speaker 1: one another fast enough would generate gravitational waves, or a 117 00:07:07,560 --> 00:07:11,000 Speaker 1: supernova explosion would create one as well. And each of 118 00:07:11,040 --> 00:07:14,120 Speaker 1: these events give off a huge amount of energy, and 119 00:07:14,200 --> 00:07:17,360 Speaker 1: some of that energy gets converted into making these gravitational waves. 120 00:07:17,400 --> 00:07:20,440 Speaker 1: So one takeaway from this prediction something that Einstein said 121 00:07:20,440 --> 00:07:25,960 Speaker 1: would happen is that any event that produces gravitational waves 122 00:07:26,200 --> 00:07:29,400 Speaker 1: is an event in which energy is being lost, So 123 00:07:29,480 --> 00:07:33,040 Speaker 1: you would expect to see less energy within that system 124 00:07:33,160 --> 00:07:36,960 Speaker 1: afterward than before. Uh. And it would be a hundred 125 00:07:37,120 --> 00:07:41,160 Speaker 1: years from the time of publication of the theory of 126 00:07:41,160 --> 00:07:45,040 Speaker 1: general relativity to the time when scientists announced that they 127 00:07:45,040 --> 00:07:50,000 Speaker 1: had detected a gravitational wave directly. And that's because gravitational 128 00:07:50,040 --> 00:07:53,840 Speaker 1: waves are devilish lye difficult to detect. And that's some 129 00:07:53,960 --> 00:07:57,880 Speaker 1: alliteration for you right there. So gravitational waves are invisible. 130 00:07:58,720 --> 00:08:01,840 Speaker 1: They don't omit any sort of a electromagnetic radiation, so 131 00:08:01,880 --> 00:08:06,240 Speaker 1: we can't see them. We can't detect them with radio detectors, 132 00:08:06,360 --> 00:08:10,480 Speaker 1: nothing like that. Uh. And that makes it pretty tricky 133 00:08:10,560 --> 00:08:12,920 Speaker 1: to figure out where they are. But they do just 134 00:08:13,000 --> 00:08:16,280 Speaker 1: pass through the universe. They don't get absorbed or scattered 135 00:08:16,400 --> 00:08:19,760 Speaker 1: the way electromagnetic radiation does. If you hold up a 136 00:08:19,800 --> 00:08:22,840 Speaker 1: mirror and light hits the mirror, light will bounce off 137 00:08:22,880 --> 00:08:25,520 Speaker 1: the mirror. That's not the case with gravitational waves. They 138 00:08:25,520 --> 00:08:29,680 Speaker 1: pass right through. UH. So it's a very different thing 139 00:08:29,880 --> 00:08:36,480 Speaker 1: than electromagnetic radiation. UM. And while they're generated from enormous events. 140 00:08:36,559 --> 00:08:39,320 Speaker 1: The gravitational waves aren't very strong by the time they 141 00:08:39,320 --> 00:08:43,600 Speaker 1: get to Earth. They are pretty weak, so weak that 142 00:08:43,720 --> 00:08:46,280 Speaker 1: you would need an incredibly sensitive tool in order to 143 00:08:46,320 --> 00:08:48,480 Speaker 1: pick them up. And also you have to be searching 144 00:08:48,520 --> 00:08:51,640 Speaker 1: at the right time, because if the event that generated 145 00:08:51,640 --> 00:08:55,920 Speaker 1: the gravitational waves happened a billion years ago, but the 146 00:08:56,000 --> 00:09:00,120 Speaker 1: location is four billion light years from Earth, then we 147 00:09:00,160 --> 00:09:03,520 Speaker 1: would have to wait another three billion years for those 148 00:09:03,600 --> 00:09:06,240 Speaker 1: gravitational waves to get to us, because again, they travel 149 00:09:06,280 --> 00:09:09,360 Speaker 1: at the speed of light, that's their limit. So you 150 00:09:09,400 --> 00:09:10,719 Speaker 1: have to be at the right place at the right 151 00:09:10,720 --> 00:09:14,000 Speaker 1: time to pick these things up. And uh, and in 152 00:09:14,080 --> 00:09:18,679 Speaker 1: some cases you might argue that that's incredibly fortuitous. Although 153 00:09:19,400 --> 00:09:23,160 Speaker 1: to be fair, uh, it looks like the events that 154 00:09:23,240 --> 00:09:27,120 Speaker 1: could generate gravitational waves happened pretty frequently throughout the universe. 155 00:09:27,400 --> 00:09:31,360 Speaker 1: But the universe is huge, so if they're happening far away, 156 00:09:31,400 --> 00:09:33,800 Speaker 1: far enough away, it will take a very long time 157 00:09:33,840 --> 00:09:37,080 Speaker 1: for that information to get to us. So before the 158 00:09:37,080 --> 00:09:41,360 Speaker 1: announcement on February eleven, sixteen, scientists had observed phenomena that 159 00:09:41,520 --> 00:09:45,800 Speaker 1: supported the existence of gravitational waves. But we're not direct 160 00:09:46,000 --> 00:09:49,920 Speaker 1: observations of a gravitational wave. Here's an example. A pair 161 00:09:49,960 --> 00:09:53,640 Speaker 1: of astronomers in Puerto Rico in the nineteen seventies noticed 162 00:09:53,679 --> 00:09:58,080 Speaker 1: that there was a binary pulsar system and they went 163 00:09:58,160 --> 00:10:01,200 Speaker 1: back to the theory of general relative because this was 164 00:10:01,200 --> 00:10:03,959 Speaker 1: a sort of system that would be exactly the type 165 00:10:03,960 --> 00:10:08,720 Speaker 1: to generate gravitational waves according to the predictions from general relativity, 166 00:10:08,880 --> 00:10:12,480 Speaker 1: and because general relativity predicted, hey, if it can create 167 00:10:12,559 --> 00:10:17,120 Speaker 1: gravitational waves, it's going to lose energy over time. They 168 00:10:17,360 --> 00:10:20,320 Speaker 1: ended up coming up with the hypothesis that, well, over time, 169 00:10:20,400 --> 00:10:24,079 Speaker 1: this binary pulsar system should start to slow down because 170 00:10:24,120 --> 00:10:27,040 Speaker 1: it's it's losing energy. It can't keep up at the 171 00:10:27,040 --> 00:10:31,480 Speaker 1: speed it's going. So they decided to keep an eye 172 00:10:31,520 --> 00:10:33,880 Speaker 1: on it. And by keeping an eye on it, I 173 00:10:33,880 --> 00:10:38,720 Speaker 1: mean they continued to observe this pulsar system over the 174 00:10:38,720 --> 00:10:41,680 Speaker 1: course of eight years, and by the end of the 175 00:10:41,720 --> 00:10:44,920 Speaker 1: eight year period, they were comparing the findings they were 176 00:10:44,920 --> 00:10:48,280 Speaker 1: observing to the predictions made by general relativity, and they 177 00:10:48,320 --> 00:10:51,760 Speaker 1: were matching up. It was. It was unfolding exactly the 178 00:10:51,800 --> 00:10:55,920 Speaker 1: way Einstein predicted it should unfold based upon his theory 179 00:10:55,920 --> 00:10:59,400 Speaker 1: of general relativity, which is incredible when you think about 180 00:10:59,400 --> 00:11:02,680 Speaker 1: it that the observations are matching up so neatly against 181 00:11:02,679 --> 00:11:07,360 Speaker 1: the predictions. Uh, you know, it just shows how how 182 00:11:07,520 --> 00:11:11,480 Speaker 1: keenly aware Einstein was of how our universe appears to work. 183 00:11:11,760 --> 00:11:16,480 Speaker 1: Keeping in mind that general relativity, while an amazing idea 184 00:11:16,840 --> 00:11:22,880 Speaker 1: collection of ideas, really it doesn't encompass everything that we know, 185 00:11:23,080 --> 00:11:26,480 Speaker 1: right it doesn't. It doesn't really address quantum mechanics, for example, 186 00:11:27,400 --> 00:11:29,480 Speaker 1: at least not in a way that incorporates it with 187 00:11:30,280 --> 00:11:35,120 Speaker 1: classical physics. But based upon what it did cover, it 188 00:11:35,160 --> 00:11:40,360 Speaker 1: seems like it was an incredibly accurate theory alright. So 189 00:11:41,800 --> 00:11:45,199 Speaker 1: this was really considered strong but indirect support of gravitational 190 00:11:45,200 --> 00:11:50,280 Speaker 1: waves because again the astronomers didn't observe gravitational waves directly. 191 00:11:50,320 --> 00:11:53,200 Speaker 1: They couldn't see them or detect them, but they could 192 00:11:53,200 --> 00:11:56,920 Speaker 1: see the effects, and again it was matching up with 193 00:11:56,960 --> 00:12:00,000 Speaker 1: the predictions made from general relativity, so it was good 194 00:12:00,040 --> 00:12:04,319 Speaker 1: it indirect evidence that gravitational waves existed. Then there was 195 00:12:04,360 --> 00:12:06,839 Speaker 1: an event a couple of years ago that you might 196 00:12:06,880 --> 00:12:12,079 Speaker 1: have heard about, when a team of researchers working on 197 00:12:12,120 --> 00:12:17,480 Speaker 1: the BICEP two telescope, which is an an Antarctica, had 198 00:12:17,480 --> 00:12:21,280 Speaker 1: announced that they thought they might have discovered evidence of 199 00:12:21,320 --> 00:12:28,360 Speaker 1: gravitational waves that supported a hypothesis called cosmic inflation. That's 200 00:12:28,360 --> 00:12:30,480 Speaker 1: a lot of information right there, So let me explain 201 00:12:30,520 --> 00:12:35,320 Speaker 1: what all that means. Cosmic inflation is a hypothesis that 202 00:12:35,360 --> 00:12:38,760 Speaker 1: relates to the Big Bang theory. So, with the Big 203 00:12:38,760 --> 00:12:42,200 Speaker 1: Bang theory, you've got this event in which the universe 204 00:12:42,400 --> 00:12:47,400 Speaker 1: undergoes a period of rapid expansion. Cosmic inflation is kind 205 00:12:47,440 --> 00:12:52,440 Speaker 1: of that rapid expansion on steroids. The idea being that, well, 206 00:12:52,600 --> 00:12:55,160 Speaker 1: when we look at our universe and we look at 207 00:12:55,200 --> 00:12:59,559 Speaker 1: the the what we can observe, it appears that are 208 00:12:59,600 --> 00:13:02,160 Speaker 1: observed aitions don't quite match up with what we would 209 00:13:02,160 --> 00:13:08,720 Speaker 1: expect if we had, uh, just steady expansion since the 210 00:13:08,760 --> 00:13:12,200 Speaker 1: Big Bang. In other words, we look at all the 211 00:13:12,240 --> 00:13:14,600 Speaker 1: information we have available to us, and it looks to 212 00:13:14,679 --> 00:13:17,839 Speaker 1: us that it doesn't quite match up. Something's got to 213 00:13:17,880 --> 00:13:22,800 Speaker 1: be wrong. Well, one possible explanation is that shortly after 214 00:13:22,840 --> 00:13:25,880 Speaker 1: the Big Bang, and by shortly I mean tend to 215 00:13:25,960 --> 00:13:29,800 Speaker 1: the negative thirty six power seconds after the Big Bang. 216 00:13:30,400 --> 00:13:32,800 Speaker 1: So you take a ten, you put a decimal point 217 00:13:32,800 --> 00:13:35,160 Speaker 1: behind the tin, then you move the decimal point to 218 00:13:35,200 --> 00:13:39,319 Speaker 1: the left thirties six times did you put seconds behind that. 219 00:13:39,360 --> 00:13:41,840 Speaker 1: We're talking a fraction of a fraction of a fraction 220 00:13:41,840 --> 00:13:47,880 Speaker 1: of a second. The universe underwent massive expansion, and it 221 00:13:48,000 --> 00:13:51,080 Speaker 1: only lasted from from that point to about ten to 222 00:13:51,120 --> 00:13:55,160 Speaker 1: the negative thirty third power or thirty second power seconds. 223 00:13:55,600 --> 00:14:01,760 Speaker 1: So again an instant. It's it's completely unimaginable, at least 224 00:14:01,880 --> 00:14:05,160 Speaker 1: for myself, how short an amount of time this was. 225 00:14:05,640 --> 00:14:10,000 Speaker 1: But that's how how quickly the universe expanded, uh significantly, 226 00:14:10,640 --> 00:14:14,960 Speaker 1: and then it slowed, but it continued to expand. Now, 227 00:14:15,120 --> 00:14:19,240 Speaker 1: if in fact cosmic inflation is correct, it solves a 228 00:14:19,320 --> 00:14:22,080 Speaker 1: lot of the problems we have between the what we 229 00:14:22,160 --> 00:14:25,280 Speaker 1: observe today and what we believe happened with the Big 230 00:14:25,320 --> 00:14:30,880 Speaker 1: Bang um and reconciles those differences. If cosmic inflation is wrong, 231 00:14:31,280 --> 00:14:34,680 Speaker 1: then something else that we believe is wrong. Right. It 232 00:14:34,760 --> 00:14:38,920 Speaker 1: means that what we observe either isn't representative of reality 233 00:14:39,040 --> 00:14:42,320 Speaker 1: somehow we're not getting a big enough picture to understand it, 234 00:14:42,440 --> 00:14:45,120 Speaker 1: or that the Big Bang theory itself is flawed in 235 00:14:45,160 --> 00:14:49,200 Speaker 1: some fundamental way. So the BICEP two team, what they 236 00:14:49,240 --> 00:14:52,920 Speaker 1: were looking for was some evidence of gravitational waves that 237 00:14:52,960 --> 00:14:56,640 Speaker 1: would have been generated during the Big Bang this would 238 00:14:56,760 --> 00:15:00,160 Speaker 1: end up supporting the cosmic inflation hypothesis. And the way 239 00:15:00,200 --> 00:15:02,120 Speaker 1: they did this was they were looking at the cosmic 240 00:15:02,200 --> 00:15:06,880 Speaker 1: microwave background or c MB. Now, the cosmic microwave background 241 00:15:06,920 --> 00:15:12,640 Speaker 1: emerged about three hundred eighty thousand years after the Big Bang. Uh. 242 00:15:12,680 --> 00:15:14,880 Speaker 1: This was still a period where the universe was so 243 00:15:15,000 --> 00:15:17,440 Speaker 1: dense that light could not pass through it. It was 244 00:15:17,600 --> 00:15:21,720 Speaker 1: dark and dense, But the cosmic microwave background formed around 245 00:15:21,760 --> 00:15:28,840 Speaker 1: that time, and the hypothesis stated, well, gravitational waves would 246 00:15:28,920 --> 00:15:34,360 Speaker 1: have affected the cosmic microwave background, polarizing some of those uh, 247 00:15:34,440 --> 00:15:38,120 Speaker 1: some of those particles really not particles, but some of 248 00:15:38,120 --> 00:15:42,080 Speaker 1: the energy polarizing some of the cosmic microwave background in 249 00:15:42,120 --> 00:15:45,280 Speaker 1: such a way that if you were to observe it, 250 00:15:45,360 --> 00:15:49,000 Speaker 1: you could see the effect of a gravitational wave passing 251 00:15:49,080 --> 00:15:54,160 Speaker 1: through the CMB. UH. And then as the universe expand 252 00:15:55,040 --> 00:15:59,600 Speaker 1: expanded rather uh, that that mark would also expand. It's 253 00:15:59,680 --> 00:16:03,600 Speaker 1: kind of like imagine leaving a fingerprint on some sort 254 00:16:03,600 --> 00:16:07,760 Speaker 1: of stretchy material and then stretching that material out. The 255 00:16:07,800 --> 00:16:10,840 Speaker 1: fingerprint is still there. It's deformed, but still there. That's 256 00:16:10,880 --> 00:16:12,920 Speaker 1: what the Bicept two team was looking for. Was this 257 00:16:13,640 --> 00:16:17,880 Speaker 1: pattern in the CMB that would indicate that gravitational waves 258 00:16:17,920 --> 00:16:20,640 Speaker 1: from the Big Bang had passed through, and if they 259 00:16:20,680 --> 00:16:23,680 Speaker 1: found that, that would be a huge support for cosmic inflation. 260 00:16:24,640 --> 00:16:27,600 Speaker 1: And in the spring of they announced that they believed 261 00:16:27,760 --> 00:16:32,680 Speaker 1: they had found such evidence, and they also invited other 262 00:16:32,760 --> 00:16:35,400 Speaker 1: researchers to take a look at their data and see 263 00:16:35,440 --> 00:16:39,920 Speaker 1: if it was verifiable or maybe they overlooked something. And 264 00:16:40,040 --> 00:16:43,920 Speaker 1: in the fall often another team said, we're sorry, but 265 00:16:44,000 --> 00:16:48,680 Speaker 1: it looks to us like space dust might have created 266 00:16:48,680 --> 00:16:52,760 Speaker 1: a false positive that what you thought it was the 267 00:16:53,000 --> 00:16:56,360 Speaker 1: polarized CMB that you had been looking for was actually 268 00:16:56,440 --> 00:16:59,400 Speaker 1: just space dust that's not actually part of the CMB. 269 00:17:00,520 --> 00:17:03,840 Speaker 1: And uh so that ended up kind of putting a 270 00:17:04,760 --> 00:17:08,200 Speaker 1: dampener on the whole celebration of finding gravitational waves to 271 00:17:08,200 --> 00:17:12,240 Speaker 1: support cosmic inflation. But even if it was completely verified, 272 00:17:12,280 --> 00:17:15,640 Speaker 1: even if BICEP two had irrefutable evidence that they had 273 00:17:15,640 --> 00:17:20,560 Speaker 1: found the presence of gravitational waves through a uh you know, 274 00:17:20,920 --> 00:17:24,639 Speaker 1: the way it affected the CNB, even then that's not 275 00:17:24,840 --> 00:17:28,600 Speaker 1: direct detection. It's still indirect. You're looking at the way 276 00:17:28,680 --> 00:17:34,280 Speaker 1: it's affected something else. So uh, you know, again, we're 277 00:17:34,280 --> 00:17:36,720 Speaker 1: still not discovering one and and part of that is 278 00:17:36,760 --> 00:17:39,640 Speaker 1: that BICEP two is a telescope. It's looking at through 279 00:17:40,040 --> 00:17:44,000 Speaker 1: the electromagnetic spectrum, and again, gravitational waves don't show up 280 00:17:44,040 --> 00:17:46,879 Speaker 1: that way, So no telescope would help you find a 281 00:17:46,880 --> 00:17:50,400 Speaker 1: gravitational wave directly. You might be able to find how 282 00:17:50,400 --> 00:17:54,920 Speaker 1: it affected something else, but not the wave itself. Now 283 00:17:54,960 --> 00:17:58,120 Speaker 1: that's not the case with the LIGO observatories. Actually it's 284 00:17:58,160 --> 00:18:03,880 Speaker 1: technically one observatory, but it has four different facilities, two detectors, 285 00:18:04,440 --> 00:18:07,800 Speaker 1: UH and to research facilities that are all part of 286 00:18:07,800 --> 00:18:12,520 Speaker 1: the LIGO observatory. LIGO itself is an acronym and it 287 00:18:12,600 --> 00:18:18,840 Speaker 1: stands for Laser Interferometer Gravitational Wave Observatory. So it's a 288 00:18:18,960 --> 00:18:21,760 Speaker 1: pair of giant detectors built on the surface of the Earth. 289 00:18:21,800 --> 00:18:27,440 Speaker 1: One is located in Hanford, Washington, the other is in Livingston, Louisiana. 290 00:18:27,640 --> 00:18:31,080 Speaker 1: Now they're about just a little under two thousand miles 291 00:18:31,119 --> 00:18:34,680 Speaker 1: apart or just over three thousand kilometers apart from each other. 292 00:18:35,280 --> 00:18:37,760 Speaker 1: And that's really important. I'll explain why in a little bit. 293 00:18:38,920 --> 00:18:40,639 Speaker 1: So to understand how they work, we also have to 294 00:18:40,640 --> 00:18:44,520 Speaker 1: talk about something else that gravitational waves do. As they 295 00:18:44,560 --> 00:18:51,200 Speaker 1: pass through space, they stretch and compress space itself. So again, 296 00:18:51,240 --> 00:18:52,520 Speaker 1: if you were to if you were to take a 297 00:18:52,520 --> 00:18:56,440 Speaker 1: piece of elastic, Let's say you've got a rubber band, 298 00:18:56,840 --> 00:19:00,639 Speaker 1: a nice thick rubber band, and you cut it so 299 00:19:00,720 --> 00:19:03,520 Speaker 1: that it's just one strip. When you pull on that 300 00:19:03,600 --> 00:19:07,760 Speaker 1: rubber band, it stretches along the line where you're applying force. 301 00:19:08,600 --> 00:19:12,480 Speaker 1: So it stretches in that direction, in the perpendicular direction 302 00:19:13,280 --> 00:19:17,560 Speaker 1: ninety degrees from where you're pulling. It compresses, it gets 303 00:19:17,800 --> 00:19:21,480 Speaker 1: more narrow, and then when you let it return to 304 00:19:21,520 --> 00:19:25,000 Speaker 1: its normal shape, it gets you know, the the long 305 00:19:25,119 --> 00:19:28,199 Speaker 1: part ends up getting shorter and the narrow part ends 306 00:19:28,240 --> 00:19:32,320 Speaker 1: up getting wider as a result, gravitational waves do this 307 00:19:32,359 --> 00:19:36,160 Speaker 1: to reality. They do this to actual space. They stretch 308 00:19:36,240 --> 00:19:39,680 Speaker 1: and compress, and it happens several times as the wave 309 00:19:39,720 --> 00:19:43,240 Speaker 1: oscillates through. Really, I should just say as the wave 310 00:19:43,280 --> 00:19:48,199 Speaker 1: passes through rather than oscillates. Uh, the distortion oscillates, but 311 00:19:48,280 --> 00:19:52,040 Speaker 1: the wave passes through. So that means the actual distance 312 00:19:52,240 --> 00:19:57,200 Speaker 1: changes between two points as that gravitational wave passes through 313 00:19:57,200 --> 00:19:59,600 Speaker 1: that area. So if we were to magnify this effect, 314 00:19:59,680 --> 00:20:05,159 Speaker 1: and I mean magnify it to a ludicrous degree, you 315 00:20:05,200 --> 00:20:07,280 Speaker 1: would be able to see it. You would actually be 316 00:20:07,320 --> 00:20:10,520 Speaker 1: able to witness this. You could stand ten feet away 317 00:20:10,560 --> 00:20:14,359 Speaker 1: from someone else, and when the gravitational wave passes through, 318 00:20:14,880 --> 00:20:16,639 Speaker 1: it would make it look like the two of you 319 00:20:16,680 --> 00:20:19,359 Speaker 1: suddenly got further away and then closer to each other, 320 00:20:19,400 --> 00:20:21,320 Speaker 1: and then further away and closer to each other, even 321 00:20:21,320 --> 00:20:25,719 Speaker 1: though you haven't moved anywhere, because the distance itself is 322 00:20:25,760 --> 00:20:31,720 Speaker 1: stretching and compressing. So why don't we see that? I mean, 323 00:20:31,720 --> 00:20:34,760 Speaker 1: if the celestial events that produce gravitational waves happen on 324 00:20:34,800 --> 00:20:37,959 Speaker 1: the order of something like every fifteen minutes, why are 325 00:20:38,040 --> 00:20:42,639 Speaker 1: we all noticing this wibbly wobbly effect. Well, it's because 326 00:20:42,640 --> 00:20:47,520 Speaker 1: the actual distortion that happens here on Earth is much 327 00:20:47,920 --> 00:20:52,880 Speaker 1: much much smaller in magnitude, so much more, so much 328 00:20:52,920 --> 00:20:56,919 Speaker 1: smaller that it's difficult to even explain. But if you 329 00:20:56,960 --> 00:21:00,879 Speaker 1: were to have a supernova explode in the Milky Way galaxy, 330 00:21:01,000 --> 00:21:05,760 Speaker 1: in our galaxy, the gravitational waves generated by that explosion 331 00:21:06,760 --> 00:21:10,080 Speaker 1: would maybe be powerful enough to distort the distance between 332 00:21:10,160 --> 00:21:13,439 Speaker 1: the Earth and the Sun by about the diameter of 333 00:21:13,480 --> 00:21:19,480 Speaker 1: a hydrogen atom, so not noticeable to any degree, and 334 00:21:19,720 --> 00:21:22,879 Speaker 1: not at least to human senses. So if you were 335 00:21:22,920 --> 00:21:24,719 Speaker 1: to even go on a smaller scale, Let's say that 336 00:21:24,760 --> 00:21:28,199 Speaker 1: you you pick two points that are a kilometer apart 337 00:21:28,280 --> 00:21:31,760 Speaker 1: here on the surface of the Earth, the amount of 338 00:21:31,760 --> 00:21:35,080 Speaker 1: distortion would be equivalent to a few thousands of the 339 00:21:35,200 --> 00:21:38,720 Speaker 1: diameter of a proton. So you're talking about a sub 340 00:21:38,760 --> 00:21:42,880 Speaker 1: atomic particle, and just a tiny, tiny, tiny fraction of 341 00:21:42,920 --> 00:21:46,600 Speaker 1: that subatomic particles diameter would be the amount of distortion 342 00:21:46,840 --> 00:21:50,080 Speaker 1: that would happen across a kilometer worth of distance here 343 00:21:50,119 --> 00:21:54,800 Speaker 1: on Earth. Again, that means it's so small that it's 344 00:21:55,280 --> 00:21:59,200 Speaker 1: incredibly difficult to detect, so much so that Einstein himself 345 00:22:00,200 --> 00:22:02,920 Speaker 1: was pretty sure we would never be able to directly 346 00:22:03,000 --> 00:22:06,480 Speaker 1: detect gravitational waves because he could not imagine a system 347 00:22:06,520 --> 00:22:09,560 Speaker 1: that would be sensitive enough to pick up such a 348 00:22:09,640 --> 00:22:14,679 Speaker 1: minute change, a distortion that's happening so quickly because it's 349 00:22:14,720 --> 00:22:18,200 Speaker 1: a fraction of a second, and it's so small as 350 00:22:18,240 --> 00:22:23,280 Speaker 1: to be unnoticeable. So the other problem here is not 351 00:22:23,359 --> 00:22:26,520 Speaker 1: just that it's such a very tiny effect that lasts 352 00:22:26,520 --> 00:22:28,960 Speaker 1: a short amount of time. It's also that a lot 353 00:22:29,000 --> 00:22:32,399 Speaker 1: of other stuff could create false positives. You can have 354 00:22:32,440 --> 00:22:38,760 Speaker 1: incredibly sensitive instrumentation, but if that instrument is really really sensitive. 355 00:22:39,280 --> 00:22:42,760 Speaker 1: Any sort of interference could set off and you could 356 00:22:42,840 --> 00:22:46,560 Speaker 1: end up getting false readings. So a change in air 357 00:22:46,600 --> 00:22:52,600 Speaker 1: pressure or temperature, or seismic activity, even a heavy truck 358 00:22:52,680 --> 00:22:56,879 Speaker 1: driving nearby could set off false results. So you'd have 359 00:22:56,920 --> 00:22:59,600 Speaker 1: to come up with a really clever way to measure distortion, 360 00:22:59,680 --> 00:23:03,600 Speaker 1: to limit vibration, and to eliminate the chance that it 361 00:23:03,680 --> 00:23:06,560 Speaker 1: was a false positive. And LEGO is the answer to 362 00:23:06,640 --> 00:23:10,439 Speaker 1: all of that. So the Lego Observatory is actually the 363 00:23:10,440 --> 00:23:14,959 Speaker 1: result of decades of collaborative work among different scientific research 364 00:23:15,000 --> 00:23:19,280 Speaker 1: centers and international bodies and universities, and all started back 365 00:23:19,320 --> 00:23:23,040 Speaker 1: in nineteen seventy nine. That's when the National Science Foundation 366 00:23:23,080 --> 00:23:25,600 Speaker 1: approved funds for cal Tech and m i T to 367 00:23:25,680 --> 00:23:30,160 Speaker 1: develop laser interferometer research and development. And a few years later, 368 00:23:30,200 --> 00:23:32,760 Speaker 1: in nineteen eighty three, Caltech and m i T submitted 369 00:23:32,760 --> 00:23:38,240 Speaker 1: a proposal for a kilometer scale detector. Uh. But keep 370 00:23:38,240 --> 00:23:40,520 Speaker 1: in mind, all right, so nineteen seventy nine you get 371 00:23:40,520 --> 00:23:44,680 Speaker 1: the funding for R and D three, there's the submission 372 00:23:44,680 --> 00:23:49,640 Speaker 1: of a proposal for a kilometer scale detector. There wouldn't 373 00:23:49,680 --> 00:23:54,240 Speaker 1: be approval for a detector until nineteen nine, so almost 374 00:23:54,320 --> 00:23:59,920 Speaker 1: a decade later, and which turns out was probably a 375 00:24:00,119 --> 00:24:05,280 Speaker 1: k because we really didn't have the technological ability to 376 00:24:05,440 --> 00:24:08,679 Speaker 1: detect things on a scale small enough to register a 377 00:24:08,720 --> 00:24:12,639 Speaker 1: gravitational wave in the first place. But but still, you know, 378 00:24:12,800 --> 00:24:15,280 Speaker 1: a decade's delay before you even get approval is still 379 00:24:15,320 --> 00:24:21,800 Speaker 1: pretty rough. Construction didn't begin until nine The inauguration of 380 00:24:21,840 --> 00:24:26,280 Speaker 1: the Ligo Observatory took place in nineteen nine, but even 381 00:24:26,359 --> 00:24:30,160 Speaker 1: then that didn't mean that the the observatory was online 382 00:24:30,200 --> 00:24:33,560 Speaker 1: collecting data. It didn't do that until two thousand two. 383 00:24:34,720 --> 00:24:39,200 Speaker 1: And here's the kicker. Eventually scientists came to the conclusion 384 00:24:39,320 --> 00:24:43,520 Speaker 1: that this Ligo Observatory was not sensitive enough to detect 385 00:24:43,560 --> 00:24:46,480 Speaker 1: gravitational waves. That despite the fact that it was this 386 00:24:47,320 --> 00:24:52,000 Speaker 1: large UH detector or pair of large detectors, actually because 387 00:24:52,040 --> 00:24:56,280 Speaker 1: again one in Louisiana one in Washington, it wasn't sensitive 388 00:24:56,440 --> 00:25:00,680 Speaker 1: enough to be effective. So it was not quite back 389 00:25:00,720 --> 00:25:03,239 Speaker 1: to the drawing board. But it didn't mean that they 390 00:25:03,280 --> 00:25:07,520 Speaker 1: had to think about how they would upgrade these facilities 391 00:25:07,960 --> 00:25:10,199 Speaker 1: so that they could be sensitive enough to pick up 392 00:25:10,240 --> 00:25:13,879 Speaker 1: a gravitational wave. So in twos ten Ligo went offline 393 00:25:14,080 --> 00:25:19,159 Speaker 1: to undergo a big overhaul, and it took four years 394 00:25:19,200 --> 00:25:22,840 Speaker 1: of construction and testing to get it into shape, and 395 00:25:22,920 --> 00:25:26,359 Speaker 1: another year to set it up for new observations, which 396 00:25:26,400 --> 00:25:28,720 Speaker 1: means that it wasn't until twenty fifteen that it was 397 00:25:28,760 --> 00:25:32,280 Speaker 1: ready to come back online. By now it's called the 398 00:25:32,320 --> 00:25:36,760 Speaker 1: Advanced Ligo Observatory, and it began collecting data in September. 399 00:25:39,119 --> 00:25:44,080 Speaker 1: Literally days after it had come online, it picked up 400 00:25:44,119 --> 00:25:48,159 Speaker 1: a gravitational wave. So that's pretty phenomenal that just a 401 00:25:48,200 --> 00:25:51,199 Speaker 1: couple of days, just a few days really after it 402 00:25:51,240 --> 00:25:54,960 Speaker 1: had been turned on again in we got a hit. 403 00:25:56,080 --> 00:25:58,480 Speaker 1: So that was incredibly exciting. So how did this happen? 404 00:25:58,800 --> 00:26:01,880 Speaker 1: How does it actually were? Well we have to take 405 00:26:01,920 --> 00:26:06,320 Speaker 1: a look at what interferometers are all about. An interferometer 406 00:26:06,520 --> 00:26:11,040 Speaker 1: uses a technique in which electromagnetic waves are superimposed on 407 00:26:11,040 --> 00:26:14,720 Speaker 1: one another in order to get information. Now, Ligo does 408 00:26:14,760 --> 00:26:17,720 Speaker 1: this with a laser beam because it's a laser interferometer, 409 00:26:18,440 --> 00:26:21,880 Speaker 1: and the laser beam gets shot through a beam splitter 410 00:26:22,280 --> 00:26:25,480 Speaker 1: and the beams, the two beams that result go down 411 00:26:25,480 --> 00:26:30,760 Speaker 1: too long vacuum tubes, so both of the Lego detectors 412 00:26:30,800 --> 00:26:34,080 Speaker 1: are in an L shape. So you've got these long, 413 00:26:34,240 --> 00:26:37,240 Speaker 1: long vacuum tubes that extend two and a half miles 414 00:26:37,320 --> 00:26:41,119 Speaker 1: or about four kilometers out from the crux from the 415 00:26:41,400 --> 00:26:47,320 Speaker 1: the angle where they meet up, and each one is 416 00:26:47,600 --> 00:26:49,480 Speaker 1: you know, they're both the same length. They have to 417 00:26:49,520 --> 00:26:53,040 Speaker 1: be exactly the same length. And the way this works 418 00:26:53,080 --> 00:26:55,680 Speaker 1: is that, uh, kind of behind the crux, you've got 419 00:26:55,680 --> 00:26:58,040 Speaker 1: a laser that shoots out a beam of light to 420 00:26:58,160 --> 00:27:01,840 Speaker 1: a beam splitter. This letter does exactly what it sounds 421 00:27:01,880 --> 00:27:04,640 Speaker 1: like it does. It splits the beam into two separate 422 00:27:04,920 --> 00:27:12,560 Speaker 1: beams with with alternating canceling wavelengths. I guess I should say, 423 00:27:12,600 --> 00:27:16,720 Speaker 1: so the the troughs and peaks on one match up 424 00:27:16,960 --> 00:27:20,160 Speaker 1: with the peaks and troughs of the other. That's really 425 00:27:20,200 --> 00:27:24,000 Speaker 1: important when we get a little further down the line here. 426 00:27:24,080 --> 00:27:29,440 Speaker 1: So one of those two beams goes down one branch 427 00:27:29,920 --> 00:27:33,720 Speaker 1: of this l shaped detector. The other beam goes down 428 00:27:33,760 --> 00:27:36,040 Speaker 1: the other branch. And keep in mind, like I said, 429 00:27:36,280 --> 00:27:38,960 Speaker 1: both of these branches are exactly the same length two 430 00:27:39,000 --> 00:27:42,200 Speaker 1: and a half miles or four kilometers. When the laser 431 00:27:42,240 --> 00:27:45,359 Speaker 1: gets to the end, they hit a mirror. Each beam 432 00:27:45,440 --> 00:27:49,440 Speaker 1: hits a mirror. They come back to the point of origin. 433 00:27:50,080 --> 00:27:55,560 Speaker 1: And because the two laser beams have these uh, these 434 00:27:55,600 --> 00:28:01,800 Speaker 1: counteracting wavelengths, they cancel each other out, so the peaks 435 00:28:01,840 --> 00:28:04,239 Speaker 1: on one cancel out the troughs of the other, and 436 00:28:04,359 --> 00:28:08,040 Speaker 1: vice versa. That means that no light gets emitted through 437 00:28:08,400 --> 00:28:11,000 Speaker 1: this system. And that's important because there's actually a light 438 00:28:11,040 --> 00:28:14,159 Speaker 1: detector that's part of this system as well. It's looking 439 00:28:14,200 --> 00:28:17,520 Speaker 1: for any sign of laser light, because a sign of 440 00:28:17,640 --> 00:28:21,280 Speaker 1: laser light would say that something has changed somehow the 441 00:28:21,440 --> 00:28:25,399 Speaker 1: distances between these or the distances represented by these two 442 00:28:25,480 --> 00:28:28,320 Speaker 1: vacuum tubes has changed, and that would be indicative of 443 00:28:28,359 --> 00:28:32,840 Speaker 1: an event like a gravitational wave moving through. So if 444 00:28:32,880 --> 00:28:38,600 Speaker 1: any light shines through, you know something has happened. Essentially, 445 00:28:38,640 --> 00:28:41,000 Speaker 1: it says that there's a mismatch in the lengths of 446 00:28:41,000 --> 00:28:44,920 Speaker 1: the vacuum tubes themselves. So when a gravitational wave passes through, 447 00:28:45,960 --> 00:28:49,760 Speaker 1: one vacuum tube will get shorter while the other gets longer. 448 00:28:50,360 --> 00:28:54,520 Speaker 1: And that's because the two tubes are offset by ninety degrees, 449 00:28:55,640 --> 00:28:58,440 Speaker 1: so one is going to be along one side of 450 00:28:58,480 --> 00:29:01,880 Speaker 1: the wave and that lengthen the other will be along 451 00:29:02,320 --> 00:29:05,480 Speaker 1: uh will be perpendicular to that and will shorten as 452 00:29:05,480 --> 00:29:08,680 Speaker 1: a result. And this means that the lasers will have 453 00:29:08,760 --> 00:29:13,280 Speaker 1: different distances to travel down. So the laser traveling the 454 00:29:13,280 --> 00:29:16,560 Speaker 1: shorter distance takes less time to get back to the crux. 455 00:29:17,120 --> 00:29:19,600 Speaker 1: The laser going down the longer distance takes more time. 456 00:29:20,040 --> 00:29:22,200 Speaker 1: And even though this is only happening within a fraction 457 00:29:22,240 --> 00:29:24,520 Speaker 1: of a second, it's long enough for us to be 458 00:29:24,560 --> 00:29:27,280 Speaker 1: able to detect the difference. And it also means that 459 00:29:27,320 --> 00:29:30,640 Speaker 1: those wave lengths don't match up anymore, they don't cancel 460 00:29:30,720 --> 00:29:33,480 Speaker 1: each other out anymore. So some of that laser light 461 00:29:33,560 --> 00:29:38,360 Speaker 1: gets admitted to the light detector, which then indicates what's 462 00:29:38,400 --> 00:29:42,680 Speaker 1: going on. It knows which which one of the branches 463 00:29:42,880 --> 00:29:46,000 Speaker 1: was short versus long, It knows how long it happened, 464 00:29:46,040 --> 00:29:48,680 Speaker 1: It knows how much it oscillated back and forth, because 465 00:29:48,720 --> 00:29:52,800 Speaker 1: obviously this is continuing as these as the gravitational wave 466 00:29:52,840 --> 00:29:56,080 Speaker 1: moves through. So you collect a lot of data in 467 00:29:56,080 --> 00:29:58,560 Speaker 1: a short amount of time. And we're talking like teeny 468 00:29:58,600 --> 00:30:01,480 Speaker 1: tiny slices of a second as we're getting all this information, 469 00:30:01,720 --> 00:30:06,680 Speaker 1: which is pretty incredible. So once you get all that data, 470 00:30:06,720 --> 00:30:10,080 Speaker 1: you can then analyze it. Actually, more importantly, before you 471 00:30:10,120 --> 00:30:13,360 Speaker 1: analyze it, you have to verify it. Now. This is 472 00:30:13,400 --> 00:30:16,640 Speaker 1: why it's important that there are two detectors, and it's 473 00:30:16,640 --> 00:30:19,120 Speaker 1: also important that they are so far apart, like three 474 00:30:19,120 --> 00:30:22,560 Speaker 1: thousand kilometers apart from each other. That's because if you 475 00:30:22,560 --> 00:30:25,560 Speaker 1: get a blip on one of them, if it's a 476 00:30:25,560 --> 00:30:28,360 Speaker 1: true gravitational wave, you should also get a blip on 477 00:30:28,440 --> 00:30:31,640 Speaker 1: the other one. And because gravitational waves move at the 478 00:30:31,640 --> 00:30:34,520 Speaker 1: speed of light, there should be a slight difference in 479 00:30:34,640 --> 00:30:38,880 Speaker 1: time when both detectors pick up on this gravitational wave, 480 00:30:39,640 --> 00:30:43,840 Speaker 1: somewhere right around ten milliseconds or less. In the case 481 00:30:43,920 --> 00:30:47,240 Speaker 1: of the one that was detected back in the fall 482 00:30:47,360 --> 00:30:50,720 Speaker 1: of two thousand fifteen but not announced until two thousand sixteen, 483 00:30:51,480 --> 00:30:56,480 Speaker 1: it hit the Louisiana detector first, and seven milliseconds later 484 00:30:56,640 --> 00:31:01,400 Speaker 1: it hit the Washington detector, So that was indicative of 485 00:31:01,440 --> 00:31:04,080 Speaker 1: something like a gravitational wave, as opposed to some local 486 00:31:04,200 --> 00:31:07,360 Speaker 1: event that would have caused interference and created a false positive. 487 00:31:07,720 --> 00:31:12,520 Speaker 1: If an earthquake had happened in Washington, then the facility 488 00:31:12,560 --> 00:31:16,040 Speaker 1: may have may have picked something up, but you wouldn't 489 00:31:16,080 --> 00:31:18,920 Speaker 1: expect to see it in Louisiana because it was a 490 00:31:18,960 --> 00:31:21,960 Speaker 1: localized event. Same thing is true if something had happened 491 00:31:22,000 --> 00:31:25,840 Speaker 1: in Louisiana. So by seeing it happen at both within 492 00:31:25,960 --> 00:31:30,080 Speaker 1: this ten millisecond time frame meant that it was a 493 00:31:30,200 --> 00:31:35,000 Speaker 1: very good candidate for a gravitational wave passing through. And 494 00:31:35,040 --> 00:31:38,240 Speaker 1: that's exactly what happened. Um it was a home run 495 00:31:38,600 --> 00:31:41,200 Speaker 1: in the first ending of the game, or even really 496 00:31:41,240 --> 00:31:44,160 Speaker 1: the first at bat of the game. It's like your 497 00:31:44,160 --> 00:31:46,720 Speaker 1: first player steps up on the first day of baseball 498 00:31:46,800 --> 00:31:50,600 Speaker 1: and knocks a home run and that defines the moment 499 00:31:50,720 --> 00:31:53,920 Speaker 1: the season. Really, that's that's the equivalent of what we 500 00:31:53,920 --> 00:32:00,240 Speaker 1: saw here on a scientific basis. Uh So the eat. 501 00:32:01,000 --> 00:32:02,640 Speaker 1: The other thing I want to talk about was how 502 00:32:02,760 --> 00:32:07,520 Speaker 1: LEGO tries to minimize the possibility of detecting a false 503 00:32:07,520 --> 00:32:10,120 Speaker 1: positive in the first place. So, yeah, false positives are 504 00:32:10,160 --> 00:32:12,280 Speaker 1: something that that they worry about, and the fact that 505 00:32:12,320 --> 00:32:15,239 Speaker 1: there are two detectors helps minimize that. But even so, 506 00:32:15,360 --> 00:32:18,160 Speaker 1: you want to eliminate the possibility of a false positive 507 00:32:18,760 --> 00:32:22,040 Speaker 1: so that you're not constantly sifting through noise looking for 508 00:32:22,080 --> 00:32:25,000 Speaker 1: a signal. Do you want to minimize noise as much 509 00:32:25,040 --> 00:32:30,360 Speaker 1: as possible. So Lego does this through using combinations of 510 00:32:30,600 --> 00:32:36,960 Speaker 1: active and passive UH vibration reduction systems. One thing that 511 00:32:37,000 --> 00:32:40,600 Speaker 1: they do is they remove the air from the tubes. 512 00:32:40,640 --> 00:32:42,760 Speaker 1: That's why their vacuum tubes they remove the air for 513 00:32:42,840 --> 00:32:46,880 Speaker 1: two reasons. One, they don't want any sound passing through 514 00:32:46,920 --> 00:32:51,680 Speaker 1: the chambers. Sound could possibly interfere with the measurements. Sound 515 00:32:51,680 --> 00:32:56,080 Speaker 1: would impact the mirrors, and even a small impact would 516 00:32:56,080 --> 00:33:01,000 Speaker 1: be enough to cause a problem. When you're measuring this laser. 517 00:33:01,520 --> 00:33:04,360 Speaker 1: For one thing, they're looking at distances when they're measuring 518 00:33:04,400 --> 00:33:08,240 Speaker 1: the changes between the two branches. You know, I mentioned 519 00:33:08,240 --> 00:33:12,400 Speaker 1: that one's getting longer, one's getting smaller. The distances they're 520 00:33:12,440 --> 00:33:15,160 Speaker 1: looking at are very very tiny. We're talking ten to 521 00:33:15,280 --> 00:33:19,360 Speaker 1: the negative nineteenth power meters. So again, you take the 522 00:33:19,440 --> 00:33:22,880 Speaker 1: number ten, you move a decimal place nineteen times to 523 00:33:22,960 --> 00:33:26,280 Speaker 1: the left of that, and you put meters at the end. 524 00:33:26,600 --> 00:33:30,880 Speaker 1: That's the distance that these lasers are are measuring the 525 00:33:30,920 --> 00:33:34,800 Speaker 1: distortion and distance. So it's very very very tiny, and 526 00:33:34,880 --> 00:33:38,400 Speaker 1: something as simple as sound could change that. So you 527 00:33:38,480 --> 00:33:40,840 Speaker 1: can't have any sound in these vacuum tubes. You've got 528 00:33:40,840 --> 00:33:44,080 Speaker 1: to get the air out. Also, air can absorb and 529 00:33:44,240 --> 00:33:48,800 Speaker 1: uh and and scatter laser light, which would interfere with 530 00:33:48,880 --> 00:33:51,080 Speaker 1: the experiment as well. So you've got to get air out. 531 00:33:52,520 --> 00:33:55,720 Speaker 1: Now dawn to the vibration reduction systems. So the active 532 00:33:55,760 --> 00:33:59,800 Speaker 1: isolation system is meant to weed out the majority of vibration. 533 00:34:00,640 --> 00:34:04,920 Speaker 1: And it's active because it is actively working against any 534 00:34:05,000 --> 00:34:10,879 Speaker 1: vibration it encounters. You've got sensors that detect vibration, they 535 00:34:10,920 --> 00:34:16,279 Speaker 1: send commands to force actuators that move in opposition to 536 00:34:16,360 --> 00:34:19,680 Speaker 1: the vibration. So it's kind of like noise canceling headphones. 537 00:34:19,960 --> 00:34:21,520 Speaker 1: If you if you put on a pair of noise 538 00:34:21,520 --> 00:34:24,359 Speaker 1: canceling headphones, what they're supposed to do is pick up 539 00:34:24,360 --> 00:34:27,960 Speaker 1: any incoming sound and then generate sound waves that are 540 00:34:28,000 --> 00:34:31,920 Speaker 1: in direct opposition of the incoming sound, so that you 541 00:34:31,960 --> 00:34:35,200 Speaker 1: get a cancelation effect. That's the same thing that these 542 00:34:35,239 --> 00:34:38,000 Speaker 1: active systems are trying to do at LIGO, except instead 543 00:34:38,000 --> 00:34:41,240 Speaker 1: of it just being sound, it's really any vibration. Although 544 00:34:41,280 --> 00:34:43,680 Speaker 1: I guess you could argue that any vibration really is sound, 545 00:34:44,080 --> 00:34:47,240 Speaker 1: so it's kind of a moot point. But anyway, they're 546 00:34:47,280 --> 00:34:52,960 Speaker 1: actively trying to counteract that vibration. But then you've got 547 00:34:52,960 --> 00:34:56,320 Speaker 1: the passive system. This is the suspension system for the mirrors, 548 00:34:57,280 --> 00:34:59,680 Speaker 1: and this is you know, the next step. So you 549 00:35:00,000 --> 00:35:04,160 Speaker 1: you've eliminated a huge percentage of the vibration at this point, 550 00:35:04,200 --> 00:35:06,600 Speaker 1: but that's not good enough. You need to eliminate as 551 00:35:06,680 --> 00:35:09,919 Speaker 1: much as close to the vibration as you possibly can. 552 00:35:11,080 --> 00:35:15,640 Speaker 1: So next we look at the suspension system of ligos mirrors, 553 00:35:15,760 --> 00:35:19,760 Speaker 1: and they are at the base of a four pendulum system. 554 00:35:19,880 --> 00:35:23,920 Speaker 1: Meaning imagine you've got a string and it ends in 555 00:35:24,000 --> 00:35:27,200 Speaker 1: a in a pendulum, a weight a mass of some sort, 556 00:35:27,840 --> 00:35:30,600 Speaker 1: and it has to be a mass of significant size 557 00:35:31,320 --> 00:35:37,040 Speaker 1: so that it will it'll um resist moving. It's the 558 00:35:37,120 --> 00:35:40,960 Speaker 1: law of inertia, you know. Uh. An object at rest 559 00:35:41,160 --> 00:35:45,440 Speaker 1: tends to stay at rest, so it will end up 560 00:35:45,480 --> 00:35:49,520 Speaker 1: absorbing a lot of vibration and minimizing it on the 561 00:35:49,560 --> 00:35:53,240 Speaker 1: other end. So you've got that first pendulum, that's pendulum 562 00:35:53,320 --> 00:35:57,200 Speaker 1: number one. From that you suspend pendulum number two. So 563 00:35:57,320 --> 00:36:01,239 Speaker 1: already you're getting fewer vibrations because pendulum number one is 564 00:36:01,280 --> 00:36:04,439 Speaker 1: picking them up. What vibrations do manage to pass through 565 00:36:04,560 --> 00:36:07,680 Speaker 1: start to get picked up by pendulum number two, and 566 00:36:07,719 --> 00:36:11,400 Speaker 1: again the law of inertia means that it will dampen 567 00:36:11,440 --> 00:36:14,520 Speaker 1: a lot of that vibration. Then you've got pendulum number three, 568 00:36:14,960 --> 00:36:17,279 Speaker 1: and then beneath that you finally have the mirror, which 569 00:36:17,360 --> 00:36:22,080 Speaker 1: is forts or about eighty eight pounds worth of mirror. Uh. 570 00:36:22,120 --> 00:36:26,320 Speaker 1: And hopefully after the active impassive systems have all taken 571 00:36:26,320 --> 00:36:29,160 Speaker 1: care of the vibration, nothing else is getting to that mirror. 572 00:36:29,719 --> 00:36:32,080 Speaker 1: By the way, you can actually test this out yourself, 573 00:36:32,120 --> 00:36:36,160 Speaker 1: if you like, by UH, getting four strings that are 574 00:36:36,440 --> 00:36:40,080 Speaker 1: all equal length and some washers, some nice heavy washers. 575 00:36:40,680 --> 00:36:43,440 Speaker 1: Tie a washer at the end of the string of 576 00:36:43,520 --> 00:36:48,560 Speaker 1: the first string. Then tie a washer um so that 577 00:36:49,040 --> 00:36:51,480 Speaker 1: one end of the string connects to washer number one, 578 00:36:51,840 --> 00:36:53,919 Speaker 1: one end of the string connects to washer number two, 579 00:36:54,600 --> 00:36:56,359 Speaker 1: and so on and so forth. And if you hold 580 00:36:56,360 --> 00:37:00,120 Speaker 1: it up and you start shaking your hand holding the stringing, 581 00:37:00,520 --> 00:37:03,719 Speaker 1: you'll notice that the washer at the top moves more 582 00:37:03,800 --> 00:37:06,600 Speaker 1: than the second washer, which moves more than the third, 583 00:37:06,960 --> 00:37:08,680 Speaker 1: And by the time you get down to the fourth one, 584 00:37:08,920 --> 00:37:11,560 Speaker 1: it's not moving much at all because it's been the 585 00:37:11,640 --> 00:37:15,400 Speaker 1: vibrations have been dampened by the previous pendulums. That's the 586 00:37:15,440 --> 00:37:20,120 Speaker 1: principle of this passive system. So that helps eliminate a 587 00:37:20,120 --> 00:37:24,360 Speaker 1: lot of that vibration. UH. Without those dampening systems in place, 588 00:37:24,440 --> 00:37:27,080 Speaker 1: the two ligo detectors would be picking up a lot 589 00:37:27,080 --> 00:37:30,920 Speaker 1: of noise. And since we're still not really sure how 590 00:37:30,960 --> 00:37:34,640 Speaker 1: often gravitational waves passed through the Earth, that would be 591 00:37:34,719 --> 00:37:38,240 Speaker 1: a problem. Now. Between two thousand two and two thousand 592 00:37:38,200 --> 00:37:40,439 Speaker 1: and ten, with the early version of LEGO, they didn't 593 00:37:40,480 --> 00:37:44,560 Speaker 1: pick up any gravitational waves at all, which we think 594 00:37:45,360 --> 00:37:49,640 Speaker 1: is because the detectors weren't sensitive enough. We think that's 595 00:37:49,680 --> 00:37:54,879 Speaker 1: the reason, but an alternative reason could be that gravitational 596 00:37:54,880 --> 00:37:57,480 Speaker 1: waves aren't as frequent as we think they are, that 597 00:37:57,560 --> 00:38:00,520 Speaker 1: they don't pass through the Earth as frequently as we 598 00:38:00,600 --> 00:38:04,759 Speaker 1: might otherwise believe. However, the opposite could be true. We 599 00:38:04,800 --> 00:38:09,000 Speaker 1: could have way more gravitational waves passing through Earth than 600 00:38:09,360 --> 00:38:13,040 Speaker 1: we had anticipated. Some of them may be so faint 601 00:38:13,120 --> 00:38:16,120 Speaker 1: that even this advanced LIGO system cannot pick it up. 602 00:38:16,360 --> 00:38:19,920 Speaker 1: There are already plans to upgrade LIGO again, and there 603 00:38:19,920 --> 00:38:24,640 Speaker 1: are other LIGO observatory systems that will that are in 604 00:38:24,719 --> 00:38:31,200 Speaker 1: development now that will also listening for gravitational waves. And 605 00:38:31,280 --> 00:38:33,680 Speaker 1: listen tends to be the way most people refer to it, 606 00:38:33,760 --> 00:38:41,439 Speaker 1: like you're listening for this universal vibration moving through the Earth. So, 607 00:38:41,960 --> 00:38:45,880 Speaker 1: because it was only a few days after they came online, 608 00:38:45,920 --> 00:38:48,680 Speaker 1: a lot of people are thinking that gravitational waves are 609 00:38:48,680 --> 00:38:53,120 Speaker 1: probably fairly common. Otherwise, it was just extraordinarily lucky that 610 00:38:53,160 --> 00:38:57,160 Speaker 1: we picked it up just days after the observatory was 611 00:38:57,520 --> 00:39:00,759 Speaker 1: online again. The one that we did pick up was 612 00:39:00,800 --> 00:39:04,200 Speaker 1: one point three billion light years away, which means that 613 00:39:04,239 --> 00:39:06,840 Speaker 1: the event happened one point three billion years ago. That 614 00:39:06,920 --> 00:39:10,400 Speaker 1: event being two black holes colliding with one another to 615 00:39:10,520 --> 00:39:16,400 Speaker 1: form a solitary black hole mass in the UH. In 616 00:39:16,480 --> 00:39:21,400 Speaker 1: the process, it vaporized about three solar masses worth of 617 00:39:21,400 --> 00:39:25,680 Speaker 1: of mass I guess, which is a huge amount to 618 00:39:25,719 --> 00:39:30,200 Speaker 1: think about being converted into energy, and the gravitational waves 619 00:39:30,560 --> 00:39:32,560 Speaker 1: emanated from there at the speed of light. So one 620 00:39:32,560 --> 00:39:36,319 Speaker 1: point three billion years later, Earth, which was one point 621 00:39:36,320 --> 00:39:40,239 Speaker 1: three billion light years away, picked him up. So in 622 00:39:40,239 --> 00:39:44,240 Speaker 1: a way, it was incredibly lucky. But if this happens 623 00:39:44,280 --> 00:39:48,640 Speaker 1: more frequently than we we originally believed, we might see 624 00:39:48,800 --> 00:39:52,360 Speaker 1: that this is not an uncommon event. It's very possible 625 00:39:52,400 --> 00:39:55,680 Speaker 1: that there are things we cannot see in the universe 626 00:39:56,440 --> 00:40:00,960 Speaker 1: that create gravitational waves. So the words, it's stuff that 627 00:40:01,040 --> 00:40:04,680 Speaker 1: does not give off electromagnetic radiation at all, but it 628 00:40:04,760 --> 00:40:07,520 Speaker 1: does create gravitational waves, meaning that we now have the 629 00:40:07,560 --> 00:40:11,279 Speaker 1: capacity to detect things that otherwise would have remained completely 630 00:40:11,320 --> 00:40:14,800 Speaker 1: undetectable by us. So one of the many reasons why 631 00:40:14,920 --> 00:40:19,640 Speaker 1: this discovery is so exciting. It opens up brand new science. 632 00:40:19,800 --> 00:40:24,359 Speaker 1: It creates a new discipline of science, gravitational astronomy, which 633 00:40:24,400 --> 00:40:27,920 Speaker 1: can really get going now because it's not that different 634 00:40:28,040 --> 00:40:33,040 Speaker 1: from when the telescope was invented. Before the telescope, astronomy 635 00:40:33,160 --> 00:40:37,399 Speaker 1: was pretty limited. You could map out astrological bodies when 636 00:40:37,440 --> 00:40:39,800 Speaker 1: you were way back in the day, before the science 637 00:40:39,800 --> 00:40:43,520 Speaker 1: of astronomy had really gotten going. Once you started figuring 638 00:40:43,520 --> 00:40:47,520 Speaker 1: out the difference between mythology and science, then astronomy really 639 00:40:47,520 --> 00:40:51,480 Speaker 1: takes over. You could map out where these different bodies go. 640 00:40:51,920 --> 00:40:54,520 Speaker 1: You could figure out which ones are must be planets 641 00:40:54,600 --> 00:40:59,759 Speaker 1: versus stars, but you couldn't really gather a lot more 642 00:40:59,760 --> 00:41:02,360 Speaker 1: in a nation than that. You can still get an 643 00:41:02,400 --> 00:41:06,239 Speaker 1: impressive amount of data just from observing with the naked eye, 644 00:41:07,000 --> 00:41:11,160 Speaker 1: but the telescope opened up a whole new world of study, 645 00:41:11,440 --> 00:41:15,960 Speaker 1: and this gravitational wave detector system has opened up a similar, 646 00:41:16,200 --> 00:41:21,240 Speaker 1: all new world that was not accessible by us until 647 00:41:21,719 --> 00:41:27,120 Speaker 1: this year real really late, last year late. So we 648 00:41:27,200 --> 00:41:29,640 Speaker 1: might end up discovering things that we've never been able 649 00:41:29,680 --> 00:41:33,960 Speaker 1: to observe before. Will also likely be able to study 650 00:41:34,080 --> 00:41:36,880 Speaker 1: all sorts of cool stuff like how fast is the universe, 651 00:41:36,920 --> 00:41:41,319 Speaker 1: expanding how much dark energy is in our universe, we 652 00:41:41,400 --> 00:41:45,600 Speaker 1: might learn more about black holes already. The gravitational wave 653 00:41:45,680 --> 00:41:49,640 Speaker 1: detected by the by ligo has given us the strongest 654 00:41:49,760 --> 00:41:53,680 Speaker 1: direct evidence of black holes. Um, I guess I should 655 00:41:53,719 --> 00:41:56,960 Speaker 1: say indirect evidence, because it's the gravity waves generated by 656 00:41:56,960 --> 00:42:02,239 Speaker 1: the black holes. But not that we ever doubted the 657 00:42:02,280 --> 00:42:04,880 Speaker 1: existence of black holes, but this is yet more evidence 658 00:42:04,920 --> 00:42:09,960 Speaker 1: in support of them. So it's really an exciting time. 659 00:42:10,440 --> 00:42:13,280 Speaker 1: We could end up learning all sorts of stuff, stuff 660 00:42:13,280 --> 00:42:16,160 Speaker 1: that we can't even anticipate right now, and that's why 661 00:42:16,239 --> 00:42:19,240 Speaker 1: it's such a big deal. I also think that Lego 662 00:42:19,360 --> 00:42:23,080 Speaker 1: is just an incredibly elegant way of detecting something that 663 00:42:23,120 --> 00:42:27,160 Speaker 1: otherwise is impossible for us to see or feel or experience. 664 00:42:28,280 --> 00:42:32,640 Speaker 1: And it's incredibly simple, at least on the principle of it. 665 00:42:32,960 --> 00:42:35,400 Speaker 1: The technology itself is very complicated because it has to 666 00:42:35,400 --> 00:42:38,680 Speaker 1: be so sensitive to detect these very tiny changes in 667 00:42:38,760 --> 00:42:44,960 Speaker 1: distance and time, but the principle behind it is elegant, 668 00:42:45,320 --> 00:42:47,359 Speaker 1: and I mean, you don't get much more simple than 669 00:42:47,400 --> 00:42:51,719 Speaker 1: a ninety degree angle. That's pretty bare bones there, but 670 00:42:51,880 --> 00:42:56,400 Speaker 1: a very clever way of detecting something that Einstein believed 671 00:42:56,520 --> 00:43:00,440 Speaker 1: was going to be beyond our ability to ever experience. 672 00:43:01,360 --> 00:43:05,640 Speaker 1: So now we have a revolutionary new way to examine 673 00:43:05,640 --> 00:43:08,600 Speaker 1: the universe. We have no way of knowing what sort 674 00:43:08,600 --> 00:43:11,040 Speaker 1: of stuff we might learn as a result, which is 675 00:43:11,040 --> 00:43:15,960 Speaker 1: incredibly exciting. And it's all due to some lasers, some 676 00:43:16,040 --> 00:43:19,680 Speaker 1: beam splitters, and some mirrors. And since we're already looking 677 00:43:19,719 --> 00:43:24,360 Speaker 1: at lots of different organizations building their own ligo observatories 678 00:43:24,440 --> 00:43:29,440 Speaker 1: and also increasing the capacity or at least the sensitivity 679 00:43:29,560 --> 00:43:35,279 Speaker 1: of the current ligo system, who knows what we're going 680 00:43:35,320 --> 00:43:39,560 Speaker 1: to see next. I'm so excited about this stuff. But guys, 681 00:43:39,760 --> 00:43:42,440 Speaker 1: I want to hear from you what you want to 682 00:43:42,960 --> 00:43:45,319 Speaker 1: you know, hear more about on future episodes of tech Stuff. 683 00:43:45,320 --> 00:43:48,359 Speaker 1: I've got a couple of things in the hopper. I've 684 00:43:48,400 --> 00:43:51,200 Speaker 1: got a couple of special guests that lined up for 685 00:43:51,280 --> 00:43:53,440 Speaker 1: the near future, so you should be getting some pretty 686 00:43:53,440 --> 00:43:57,640 Speaker 1: cool episodes pretty soon. And I also want to examine 687 00:43:57,800 --> 00:44:00,400 Speaker 1: UH one topic. I'm probably gonna try and get one 688 00:44:00,400 --> 00:44:01,960 Speaker 1: of the stuff they don't want you to know. Guys 689 00:44:01,960 --> 00:44:05,640 Speaker 1: to come in here with me to talk about back 690 00:44:05,719 --> 00:44:11,399 Speaker 1: door UH access to things like encryption systems and why 691 00:44:11,480 --> 00:44:13,720 Speaker 1: was that such a big deal and why did Apple 692 00:44:13,840 --> 00:44:16,239 Speaker 1: respond the way it did and why should we be 693 00:44:16,280 --> 00:44:20,440 Speaker 1: happy about it? Because I think that's a really important 694 00:44:20,480 --> 00:44:23,120 Speaker 1: topic and uh, I would love to get them on 695 00:44:23,239 --> 00:44:24,520 Speaker 1: the show, or at least one of them on the 696 00:44:24,520 --> 00:44:26,960 Speaker 1: show to kind of talk about it, So keep an 697 00:44:26,960 --> 00:44:29,359 Speaker 1: ear out for that as well. If you have any 698 00:44:29,360 --> 00:44:32,560 Speaker 1: suggestions for future topics, please get in touch with me 699 00:44:32,680 --> 00:44:35,040 Speaker 1: let me know what you would like to hear. The 700 00:44:35,200 --> 00:44:38,080 Speaker 1: email address for this show is tech stuff at how 701 00:44:38,160 --> 00:44:40,680 Speaker 1: stuff works dot com, or you can drop me along 702 00:44:40,800 --> 00:44:43,200 Speaker 1: on Twitter or Facebook. The handle it both of those 703 00:44:43,280 --> 00:44:46,520 Speaker 1: is text stuff H s W and I will talk 704 00:44:46,520 --> 00:44:56,360 Speaker 1: to you again really soon for more on this and 705 00:44:56,400 --> 00:45:02,880 Speaker 1: bothands of other topics how stuff works dot com, wh 706 00:45:03,760 --> 00:45:05,040 Speaker 1: wh whon