0 00:00:00,000 --> 00:00:30,000 Dear viewer, these subtitles were generated by a machine via the service Trint and therefore are (very) buggy. If you are capable, please help us to create good quality subtitles: https://c3subtitles.de/talk/718 Thanks! 1 00:00:14,860 --> 00:00:16,959 For the next talk, we will hear 2 00:00:16,960 --> 00:00:19,179 about how to get together 3 00:00:19,180 --> 00:00:21,879 lasers and dark matter. 4 00:00:21,880 --> 00:00:24,129 So our 5 00:00:24,130 --> 00:00:26,289 speaker for the next grant 6 00:00:26,290 --> 00:00:29,229 studied physics in Hanover and taught 7 00:00:29,230 --> 00:00:31,869 astro astronomy in 8 00:00:31,870 --> 00:00:34,379 remote places like Tanzania. 9 00:00:34,380 --> 00:00:36,429 He is a postdoc at the University of 10 00:00:36,430 --> 00:00:38,499 Florida, where he now works on 11 00:00:38,500 --> 00:00:41,079 the apps instrument 12 00:00:41,080 --> 00:00:43,149 or device that he will talk to 13 00:00:43,150 --> 00:00:45,639 you about and will maybe 14 00:00:45,640 --> 00:00:47,739 give you the chance to one 15 00:00:47,740 --> 00:00:50,079 day actually know 16 00:00:50,080 --> 00:00:52,419 that at least where the dark matter 17 00:00:52,420 --> 00:00:55,719 is that you might want to own. 18 00:00:55,720 --> 00:00:57,789 So please welcome with me 19 00:00:57,790 --> 00:01:00,159 Simon Barker 20 00:01:00,160 --> 00:01:02,559 with Eavesdropping on the Dark Cosmos, 21 00:01:02,560 --> 00:01:03,560 given Wylma Plus. 22 00:01:10,340 --> 00:01:12,559 Well, hi, thanks 23 00:01:12,560 --> 00:01:14,929 for having me. Thank you for being here. 24 00:01:14,930 --> 00:01:17,449 And did you know that the screen 25 00:01:17,450 --> 00:01:19,729 behind me has two million 26 00:01:19,730 --> 00:01:21,889 pixels, let's say, 27 00:01:21,890 --> 00:01:24,169 just for fun, let's assume 28 00:01:24,170 --> 00:01:26,389 this screen is all there 29 00:01:26,390 --> 00:01:28,399 is and the entire universe. 30 00:01:28,400 --> 00:01:31,249 So if that was the case, 31 00:01:31,250 --> 00:01:33,799 this screen would be 32 00:01:33,800 --> 00:01:36,079 dark for 95 percent. 33 00:01:36,080 --> 00:01:37,639 95 percent of the screen would be 34 00:01:37,640 --> 00:01:39,109 completely invisible. 35 00:01:39,110 --> 00:01:41,269 There would be another like eighty five 36 00:01:41,270 --> 00:01:43,399 thousand pixels, which are utterly 37 00:01:43,400 --> 00:01:44,400 boring. 38 00:01:45,050 --> 00:01:46,999 Then we have some cool, like 10000 39 00:01:47,000 --> 00:01:49,309 asphyxiates, which are made of stars. 40 00:01:49,310 --> 00:01:50,539 That's nice. 41 00:01:50,540 --> 00:01:52,609 We have elusive neutrinos 42 00:01:52,610 --> 00:01:55,339 making up like 6000 pixels. 43 00:01:55,340 --> 00:01:57,259 And do you know what the small portion 44 00:01:57,260 --> 00:01:58,609 down there is? 45 00:01:58,610 --> 00:02:01,759 622 pixels. 46 00:02:01,760 --> 00:02:03,769 That is you. That is me. 47 00:02:03,770 --> 00:02:05,179 That is this planet. 48 00:02:05,180 --> 00:02:07,579 This is all the higher elements like 49 00:02:07,580 --> 00:02:09,709 oxygen and carbon, like gold and 50 00:02:09,710 --> 00:02:10,939 plutonium. 51 00:02:10,940 --> 00:02:13,639 That is all there is of matter 52 00:02:13,640 --> 00:02:14,599 we care about. 53 00:02:14,600 --> 00:02:15,600 Usually 54 00:02:17,090 --> 00:02:19,339 astrophysicists care 55 00:02:19,340 --> 00:02:21,409 about a little bit more so 56 00:02:21,410 --> 00:02:23,089 they don't care about zero point zero 57 00:02:23,090 --> 00:02:24,799 three percent, but more like about the 58 00:02:24,800 --> 00:02:27,169 five percent over 59 00:02:27,170 --> 00:02:28,170 there on the right. 60 00:02:29,300 --> 00:02:31,609 I myself care about the ninety 61 00:02:31,610 --> 00:02:32,959 five percent. 62 00:02:32,960 --> 00:02:35,089 So I'm interested in the stuff you 63 00:02:35,090 --> 00:02:37,369 can't see in the invisible dark 64 00:02:37,370 --> 00:02:38,629 part of the cosmos. 65 00:02:38,630 --> 00:02:41,149 So welcome to 66 00:02:41,150 --> 00:02:44,119 Eavesdropping on the Dark Cosmos. 67 00:02:44,120 --> 00:02:45,979 I'm here on behalf of the Max Planck 68 00:02:45,980 --> 00:02:48,049 Institute for Gravitation of Physics and 69 00:02:48,050 --> 00:02:50,629 Hanover and the University of Florida 70 00:02:50,630 --> 00:02:52,909 in Gainesville, United States. 71 00:02:52,910 --> 00:02:54,259 My name is Simon Bach. 72 00:02:54,260 --> 00:02:56,839 And before I would 73 00:02:56,840 --> 00:02:59,029 like before I continue to 74 00:02:59,030 --> 00:03:01,219 talk about the dark side of the cosmos, 75 00:03:01,220 --> 00:03:03,499 I would first like to explain to you 76 00:03:03,500 --> 00:03:05,509 what I mean when I talk about Cosmos or 77 00:03:05,510 --> 00:03:07,759 universe, what is our universe? 78 00:03:09,050 --> 00:03:10,759 So I'm pretty sure you've heard that our 79 00:03:10,760 --> 00:03:13,039 universe started in a big bang and 80 00:03:13,040 --> 00:03:15,169 here we have the size of 81 00:03:15,170 --> 00:03:16,879 the universe over it. 82 00:03:18,200 --> 00:03:20,449 It took three hundred eighty thousand 83 00:03:20,450 --> 00:03:22,699 years after the Big Bang 84 00:03:22,700 --> 00:03:25,189 for the universe to expand 85 00:03:25,190 --> 00:03:27,469 to a size where the density 86 00:03:27,470 --> 00:03:29,569 was low enough so that light 87 00:03:29,570 --> 00:03:32,209 could pass through the universe 88 00:03:32,210 --> 00:03:34,429 through the very first events we can 89 00:03:34,430 --> 00:03:36,439 observe happened three hundred eighty 90 00:03:36,440 --> 00:03:38,869 thousand years after the Big Bang. 91 00:03:38,870 --> 00:03:41,059 Since then, thirteen point eight 92 00:03:41,060 --> 00:03:43,129 billion years have passed and 93 00:03:43,130 --> 00:03:45,919 the universe became quite bigger. 94 00:03:45,920 --> 00:03:48,229 Actually, the universe right now 95 00:03:48,230 --> 00:03:50,569 has a radius of forty 96 00:03:50,570 --> 00:03:52,669 six billion 97 00:03:52,670 --> 00:03:55,039 billion billion light years, so diameter 98 00:03:55,040 --> 00:03:57,799 of ninety two billion light years. 99 00:03:57,800 --> 00:03:59,869 And now you may wonder how could 100 00:03:59,870 --> 00:04:03,139 we see something 46 101 00:04:03,140 --> 00:04:05,419 billion light years away 102 00:04:05,420 --> 00:04:07,489 if the light had only thirteen point 103 00:04:07,490 --> 00:04:09,589 eight billion years time to 104 00:04:09,590 --> 00:04:10,759 Treva? 105 00:04:10,760 --> 00:04:11,760 What? 106 00:04:12,830 --> 00:04:15,769 Back then, when the light originated, 107 00:04:15,770 --> 00:04:17,958 like 380000 years after the Big 108 00:04:17,959 --> 00:04:20,359 Bang, the universe was much smaller, 109 00:04:20,360 --> 00:04:22,489 actually just roughly 40 110 00:04:22,490 --> 00:04:23,990 million light years across. 111 00:04:25,710 --> 00:04:27,899 That's when the light from the 112 00:04:27,900 --> 00:04:29,999 edge of the universe started to travel 113 00:04:30,000 --> 00:04:32,669 towards our point in space 114 00:04:32,670 --> 00:04:34,799 and the universe expanded 115 00:04:34,800 --> 00:04:36,959 during the time to try 116 00:04:36,960 --> 00:04:38,249 to reach us. 117 00:04:38,250 --> 00:04:40,919 So it's like the malls on the rubber band 118 00:04:40,920 --> 00:04:42,989 pulling apart and it took the light 119 00:04:42,990 --> 00:04:44,879 thirteen point eight billion years in 120 00:04:44,880 --> 00:04:47,039 order to basically cross 40 million light 121 00:04:47,040 --> 00:04:48,299 years. 122 00:04:48,300 --> 00:04:50,729 And the universe expanded since then 123 00:04:50,730 --> 00:04:52,829 to ninety two billion light 124 00:04:52,830 --> 00:04:54,089 years in diameter. 125 00:04:54,090 --> 00:04:56,339 So that's what I speak about 126 00:04:56,340 --> 00:04:58,469 when I say our universe or more 127 00:04:58,470 --> 00:05:00,389 precisely, my universe. 128 00:05:00,390 --> 00:05:02,909 I am in the center of this universe. 129 00:05:02,910 --> 00:05:05,009 If I moved like five meters to 130 00:05:05,010 --> 00:05:07,109 the left, my universe would 131 00:05:07,110 --> 00:05:09,359 expand five meters to the left and 132 00:05:09,360 --> 00:05:10,709 contract five meters. 133 00:05:10,710 --> 00:05:12,959 Right. So you all have 134 00:05:12,960 --> 00:05:15,389 different local universes around you. 135 00:05:15,390 --> 00:05:17,789 And of course, they are universes 136 00:05:17,790 --> 00:05:19,889 out there far, far away 137 00:05:19,890 --> 00:05:22,229 with like aliens and their centers, 138 00:05:22,230 --> 00:05:24,599 which we could never reach, which 139 00:05:24,600 --> 00:05:26,919 would have no causal connection to us. 140 00:05:26,920 --> 00:05:28,289 We can see there. 141 00:05:28,290 --> 00:05:29,519 We can't interact there. 142 00:05:29,520 --> 00:05:31,379 It's universes of their own, but they are 143 00:05:31,380 --> 00:05:32,729 in our space time continuum. 144 00:05:32,730 --> 00:05:35,039 It's nothing strange, just too far away 145 00:05:35,040 --> 00:05:36,989 to be counted as part of our universe. 146 00:05:38,580 --> 00:05:41,369 Anyway, our universe 147 00:05:41,370 --> 00:05:43,829 looks like that we can do pictures 148 00:05:43,830 --> 00:05:45,029 of it. 149 00:05:45,030 --> 00:05:46,889 We can see that there are billions and 150 00:05:46,890 --> 00:05:48,449 billions of galaxies out there. 151 00:05:50,430 --> 00:05:52,559 Can we yes, 152 00:05:52,560 --> 00:05:54,779 billions and billions of galaxies, each 153 00:05:54,780 --> 00:05:56,969 galaxy contains billions 154 00:05:56,970 --> 00:05:58,589 and billions of stars. 155 00:06:00,080 --> 00:06:02,689 It's a huge space, we can see 156 00:06:02,690 --> 00:06:04,849 planets and nebula, we can 157 00:06:04,850 --> 00:06:07,609 see jets emitted from black holes, 158 00:06:07,610 --> 00:06:10,219 we can do pictures, but 159 00:06:10,220 --> 00:06:11,779 actually that's all we do. 160 00:06:11,780 --> 00:06:14,089 Or we know about the universe as 161 00:06:14,090 --> 00:06:15,920 it looks like we know. 162 00:06:17,390 --> 00:06:20,059 From light electromagnetic 163 00:06:20,060 --> 00:06:22,189 radiation, that's all 164 00:06:22,190 --> 00:06:23,190 we can do. 165 00:06:24,560 --> 00:06:26,899 These are the Maxwell equations, 166 00:06:26,900 --> 00:06:28,729 they describe light. 167 00:06:28,730 --> 00:06:31,009 So one solution of some extra 168 00:06:31,010 --> 00:06:32,989 equations is the differential 169 00:06:32,990 --> 00:06:35,359 differential WAF equation, which 170 00:06:35,360 --> 00:06:38,179 in the end results in periodic 171 00:06:38,180 --> 00:06:40,459 oscillating electric and magnetic 172 00:06:40,460 --> 00:06:42,829 fields that what we call light that 173 00:06:42,830 --> 00:06:44,779 an electromagnetic wife. 174 00:06:44,780 --> 00:06:46,389 And we use this on Earth as well. 175 00:06:47,840 --> 00:06:48,989 We use it to see other. 176 00:06:50,120 --> 00:06:52,759 So a light rain, electromagnetic magnetic 177 00:06:52,760 --> 00:06:55,639 wave will bounce off stuff. 178 00:06:55,640 --> 00:06:58,249 Different materials only reflect 179 00:06:58,250 --> 00:07:00,229 certain frequencies of the 180 00:07:00,230 --> 00:07:01,579 electromagnetic wave. 181 00:07:01,580 --> 00:07:03,889 And then we receive this wave 182 00:07:03,890 --> 00:07:06,109 as our eyes and interpret the 183 00:07:06,110 --> 00:07:08,329 different frequencies as colors 184 00:07:08,330 --> 00:07:09,769 in our brain. 185 00:07:09,770 --> 00:07:11,149 So different colors are nothing but 186 00:07:11,150 --> 00:07:13,549 different frequencies of this oscillating 187 00:07:13,550 --> 00:07:15,619 field. But again, all we know about the 188 00:07:15,620 --> 00:07:17,029 universe, we know from light. 189 00:07:18,140 --> 00:07:19,999 Wouldn't it be nice if we could not only 190 00:07:20,000 --> 00:07:22,789 see the universe, but also 191 00:07:22,790 --> 00:07:24,079 hear it? 192 00:07:24,080 --> 00:07:27,109 So we need all these different spacecraft 193 00:07:27,110 --> 00:07:29,929 in order to cover the entire range 194 00:07:29,930 --> 00:07:32,719 of electromagnetic waves there. 195 00:07:32,720 --> 00:07:34,969 But there's no way to listen to 196 00:07:34,970 --> 00:07:36,799 when events happening out there in the 197 00:07:36,800 --> 00:07:38,539 cosmos. It's all still just 198 00:07:38,540 --> 00:07:39,859 electromagnetic radiation. 199 00:07:41,040 --> 00:07:43,159 So how could we listen to 200 00:07:43,160 --> 00:07:46,159 the cosmos here on Earth? 201 00:07:46,160 --> 00:07:48,439 We listen through pressure waves 202 00:07:48,440 --> 00:07:50,709 in air, so 203 00:07:50,710 --> 00:07:53,719 sound waves travel through a medium. 204 00:07:53,720 --> 00:07:54,979 Do we have a medium in space? 205 00:07:54,980 --> 00:07:56,869 No one space. No one can hear you scream. 206 00:07:56,870 --> 00:07:57,889 That's a problem. 207 00:07:57,890 --> 00:08:00,769 We can't transmit sound through space, 208 00:08:00,770 --> 00:08:02,479 but don't we have another medium out 209 00:08:02,480 --> 00:08:03,439 there? 210 00:08:03,440 --> 00:08:04,909 In fact, we do. 211 00:08:04,910 --> 00:08:07,099 Since 100 years we know 212 00:08:07,100 --> 00:08:09,589 from the Einstein field equations 213 00:08:09,590 --> 00:08:12,139 that there is something called space 214 00:08:12,140 --> 00:08:13,459 time. 215 00:08:13,460 --> 00:08:15,769 And the Einstein field equations told 216 00:08:15,770 --> 00:08:18,229 us that gravity 217 00:08:18,230 --> 00:08:20,449 is nothing but curvature of space time. 218 00:08:20,450 --> 00:08:22,609 So you have a massive object and 219 00:08:22,610 --> 00:08:24,859 this massive object is curving 220 00:08:24,860 --> 00:08:26,149 spacetime. 221 00:08:26,150 --> 00:08:28,369 And then smaller objects do nothing 222 00:08:28,370 --> 00:08:30,139 but falling into the curvature of the 223 00:08:30,140 --> 00:08:31,579 space time. 224 00:08:31,580 --> 00:08:33,739 Just bend space time like Schnur's, Earth 225 00:08:33,740 --> 00:08:35,749 is curving space time and I am falling 226 00:08:35,750 --> 00:08:37,219 into the curvature of space time. 227 00:08:37,220 --> 00:08:39,168 I'm attracted by the gravitational force 228 00:08:39,169 --> 00:08:41,029 of the earth. That's what I'm seeing. 229 00:08:41,030 --> 00:08:42,859 But in reality, it's just curved space 230 00:08:42,860 --> 00:08:44,479 time. So we know there's space time 231 00:08:44,480 --> 00:08:47,689 everywhere and space time can be curved. 232 00:08:47,690 --> 00:08:49,879 Country transmit waves through space 233 00:08:49,880 --> 00:08:51,979 time where we would have 234 00:08:51,980 --> 00:08:54,199 to see if this equations, the ancient 235 00:08:54,200 --> 00:08:56,389 feud equations have way solutions. 236 00:08:56,390 --> 00:08:57,739 Yes, they have. 237 00:08:57,740 --> 00:09:00,079 And then we would need to find conditions 238 00:09:00,080 --> 00:09:02,569 under which astrophysical sources 239 00:09:02,570 --> 00:09:04,009 could emit gravitational waves. 240 00:09:04,010 --> 00:09:06,109 So what does a star have to do in 241 00:09:06,110 --> 00:09:08,149 order to emit gravitational waves in the 242 00:09:08,150 --> 00:09:09,150 fabric of space time? 243 00:09:10,400 --> 00:09:12,499 Some years ago we did some 244 00:09:12,500 --> 00:09:13,500 YouTube videos 245 00:09:14,630 --> 00:09:16,879 basically exactly about that, like 246 00:09:16,880 --> 00:09:18,349 what does a star have to do in order to 247 00:09:18,350 --> 00:09:20,629 emit gravitational waves and 248 00:09:20,630 --> 00:09:22,459 just listen to YouTube for a second or 249 00:09:22,460 --> 00:09:23,460 so? 250 00:09:24,380 --> 00:09:26,509 Yeah, normally we 251 00:09:26,510 --> 00:09:27,769 would have to solve the calculations 252 00:09:27,770 --> 00:09:29,389 involved in Einstein's theory in order to 253 00:09:29,390 --> 00:09:30,709 understand it. 254 00:09:30,710 --> 00:09:31,909 Say that for a system to emit 255 00:09:31,910 --> 00:09:33,799 gravitational waves, it only needs a 256 00:09:33,800 --> 00:09:35,599 non-zero third time derivative of the 257 00:09:35,600 --> 00:09:37,879 quadripolar of its energy tensor. 258 00:09:37,880 --> 00:09:39,859 Funnily enough, this is a bit complicated 259 00:09:39,860 --> 00:09:41,569 to intuitively understand. 260 00:09:41,570 --> 00:09:43,549 Yeah, that's a math. 261 00:09:43,550 --> 00:09:45,829 So you have to stress energy tensor, 262 00:09:45,830 --> 00:09:47,719 which basically describes energy and 263 00:09:47,720 --> 00:09:49,819 matter. And if the time derivative 264 00:09:49,820 --> 00:09:52,129 of the quadruple moment of the stress 265 00:09:52,130 --> 00:09:53,989 energy transfer of the ancient field 266 00:09:53,990 --> 00:09:56,209 equations, if that is not zero, 267 00:09:56,210 --> 00:09:57,739 then there will be gravitational waves 268 00:09:57,740 --> 00:09:58,969 easy enough. 269 00:09:58,970 --> 00:10:01,129 Actually, there's the picture 270 00:10:01,130 --> 00:10:02,599 I can give you. It's very easy to 271 00:10:02,600 --> 00:10:05,239 understand. All we need in order to 272 00:10:05,240 --> 00:10:07,909 have gravitational waves are accelerated 273 00:10:07,910 --> 00:10:10,579 objects, massive objects 274 00:10:10,580 --> 00:10:11,809 that made it to stars. 275 00:10:11,810 --> 00:10:13,879 And Robert basically also 276 00:10:13,880 --> 00:10:15,619 me spinning. 277 00:10:15,620 --> 00:10:17,719 I'm accelerating my hands in 278 00:10:17,720 --> 00:10:18,859 a circle. 279 00:10:18,860 --> 00:10:21,199 This is steering up spacetime. 280 00:10:21,200 --> 00:10:23,629 That's a non-zero time derivative 281 00:10:23,630 --> 00:10:25,039 and so on and so forth. 282 00:10:25,040 --> 00:10:26,959 And this gravitational waves are 283 00:10:26,960 --> 00:10:28,369 transmitted throughout the entire 284 00:10:28,370 --> 00:10:30,289 universe. And there are lots of objects 285 00:10:30,290 --> 00:10:31,519 out there that are constantly 286 00:10:31,520 --> 00:10:32,839 accelerated. 287 00:10:32,840 --> 00:10:35,899 So let's take two galaxies 288 00:10:35,900 --> 00:10:38,089 colliding, merging two supermassive 289 00:10:38,090 --> 00:10:40,249 black holes at their centers, 290 00:10:40,250 --> 00:10:42,529 two black holes colliding, huge 291 00:10:42,530 --> 00:10:44,659 amounts of matter accelerated 292 00:10:44,660 --> 00:10:45,949 rapidly. 293 00:10:45,950 --> 00:10:47,929 You have smaller stars or small black 294 00:10:47,930 --> 00:10:50,029 holes, neutron stars falling into 295 00:10:50,030 --> 00:10:52,159 supermassive black holes. 296 00:10:52,160 --> 00:10:54,049 Of course, this is accelerated metter 297 00:10:54,050 --> 00:10:55,849 producing gravitational waves. 298 00:10:55,850 --> 00:10:57,509 Why are they falling? 299 00:10:57,510 --> 00:10:58,510 You have. 300 00:10:59,410 --> 00:11:01,789 Very tight binary star system 301 00:11:01,790 --> 00:11:04,029 so close together that 302 00:11:04,030 --> 00:11:05,949 the companion starts actually sucking off 303 00:11:05,950 --> 00:11:08,289 metter from its bigger one until 304 00:11:08,290 --> 00:11:10,689 it explodes like a huge supernova, 305 00:11:10,690 --> 00:11:12,879 explosions accelerate and Tetragon 306 00:11:12,880 --> 00:11:14,759 should produce gravitational waves. 307 00:11:15,760 --> 00:11:18,339 And you may have like artificial 308 00:11:18,340 --> 00:11:20,169 sources of gravitational waves. 309 00:11:20,170 --> 00:11:22,239 Spaceship's accelerated very 310 00:11:22,240 --> 00:11:24,369 fast should produce gravitational. 311 00:11:27,960 --> 00:11:30,059 All that I just shown you, 312 00:11:30,060 --> 00:11:31,309 it's not science fiction, 313 00:11:32,970 --> 00:11:34,230 no, wait for it. 314 00:11:37,090 --> 00:11:39,189 We see rapidly spinning neutron 315 00:11:39,190 --> 00:11:41,409 stars, Pulsers, we 316 00:11:41,410 --> 00:11:44,169 see these vampyre stars, 317 00:11:44,170 --> 00:11:46,449 we can see we can track 318 00:11:46,450 --> 00:11:48,729 the orbits of stars circling around 319 00:11:48,730 --> 00:11:50,049 supermassive black holes. 320 00:11:50,050 --> 00:11:51,879 We see supernova explosions. 321 00:11:51,880 --> 00:11:54,159 And yes, we even have a theory 322 00:11:54,160 --> 00:11:56,109 on how to build a warp drive. 323 00:11:56,110 --> 00:11:58,299 We cannot do that now and we are not even 324 00:11:58,300 --> 00:12:00,249 sure if it's actually possible. 325 00:12:00,250 --> 00:12:02,709 But this is the only way we know 326 00:12:02,710 --> 00:12:04,929 that could propel a spaceship faster 327 00:12:04,930 --> 00:12:06,159 than the speed of light that is not 328 00:12:06,160 --> 00:12:07,689 forbidden by physical laws. 329 00:12:07,690 --> 00:12:09,129 And that is pretty cool. 330 00:12:09,130 --> 00:12:11,559 And it involves an artificial curvature 331 00:12:11,560 --> 00:12:13,509 of space time and some negative energy. 332 00:12:13,510 --> 00:12:14,799 But that's just a technical issue. 333 00:12:19,980 --> 00:12:22,349 But we know that if a spaceship 334 00:12:22,350 --> 00:12:24,509 would enter this warp bubble, it would 335 00:12:24,510 --> 00:12:26,339 produce gravitational waves. 336 00:12:26,340 --> 00:12:28,499 So when we would detect gravitational 337 00:12:28,500 --> 00:12:30,869 waves, we could at least say, no, 338 00:12:30,870 --> 00:12:32,939 no one out here in our universe is 339 00:12:32,940 --> 00:12:34,409 using warp drive. So maybe it's not 340 00:12:34,410 --> 00:12:35,399 possible at all. 341 00:12:35,400 --> 00:12:37,019 Or we could detect, like we have a warp 342 00:12:37,020 --> 00:12:38,519 drive detect or know if we have 343 00:12:38,520 --> 00:12:39,679 gravitational waves detector. 344 00:12:41,040 --> 00:12:42,119 Let's see. 345 00:12:42,120 --> 00:12:43,120 So 346 00:12:45,210 --> 00:12:47,309 how actually can we detect gravitational 347 00:12:47,310 --> 00:12:49,229 waves? The biggest effect of 348 00:12:49,230 --> 00:12:51,659 gravitational waves on us 349 00:12:51,660 --> 00:12:54,179 is a change in distance. 350 00:12:54,180 --> 00:12:55,739 You're sitting there where you sit and 351 00:12:55,740 --> 00:12:57,989 you don't move at all and let me 352 00:12:57,990 --> 00:13:00,419 stand over here and not move. 353 00:13:00,420 --> 00:13:02,489 And no gravitational waves is passing 354 00:13:02,490 --> 00:13:04,649 through the earth. 355 00:13:04,650 --> 00:13:07,469 What it does is it periodically changes 356 00:13:07,470 --> 00:13:09,989 the distance between us 357 00:13:09,990 --> 00:13:12,419 by stretching space time between us 358 00:13:12,420 --> 00:13:14,099 and compressing it again. 359 00:13:14,100 --> 00:13:15,929 So you don't move? I don't move, but our 360 00:13:15,930 --> 00:13:18,659 distance is changing periodically. 361 00:13:18,660 --> 00:13:19,729 That's a weird concept. 362 00:13:20,850 --> 00:13:23,159 But now we know how to how to detect 363 00:13:23,160 --> 00:13:25,379 gravitational waves or we need to do 364 00:13:25,380 --> 00:13:28,009 is measure distances like. 365 00:13:28,010 --> 00:13:28,949 Like really. Really. 366 00:13:28,950 --> 00:13:30,119 Exactly. 367 00:13:30,120 --> 00:13:32,189 The big issue is that if 368 00:13:32,190 --> 00:13:34,259 a strong gravitational wave 369 00:13:34,260 --> 00:13:36,509 hits our solar system, 370 00:13:36,510 --> 00:13:39,029 then the distance between Earth and sun 371 00:13:39,030 --> 00:13:41,099 will change by the fraction of the 372 00:13:41,100 --> 00:13:42,899 diameter of an atom. 373 00:13:42,900 --> 00:13:44,789 And that's like distance between Earth 374 00:13:44,790 --> 00:13:45,989 and sun. 375 00:13:45,990 --> 00:13:47,109 So that's what we need to do. 376 00:13:47,110 --> 00:13:49,779 That's how precise we need to become. 377 00:13:49,780 --> 00:13:51,839 We need to measure the distance 378 00:13:51,840 --> 00:13:54,239 between Earth and Sun 379 00:13:54,240 --> 00:13:55,890 with the precision of one atom. 380 00:13:57,270 --> 00:13:58,270 Technical issues. 381 00:14:01,170 --> 00:14:02,190 We actually solve them, 382 00:14:04,260 --> 00:14:05,260 so. 383 00:14:07,860 --> 00:14:10,199 OK, maybe let's start first with 384 00:14:10,200 --> 00:14:12,869 what we expect to detect, 385 00:14:12,870 --> 00:14:14,999 if we could measure that, if 386 00:14:15,000 --> 00:14:16,709 we could measure the distance between us 387 00:14:16,710 --> 00:14:18,869 and stand by the diameter of an atom 388 00:14:18,870 --> 00:14:21,029 and then amplify the signal and convert 389 00:14:21,030 --> 00:14:23,429 the frequencies to audio 390 00:14:23,430 --> 00:14:25,499 waves, we could listen to the 391 00:14:25,500 --> 00:14:27,419 universe. We could listen to start 392 00:14:27,420 --> 00:14:29,189 exploding. We could listen to black holes 393 00:14:29,190 --> 00:14:31,649 merging. And I brought some audio files 394 00:14:31,650 --> 00:14:33,749 of like 395 00:14:33,750 --> 00:14:35,909 artificially generated signals that we 396 00:14:35,910 --> 00:14:37,379 expect to hear. 397 00:14:37,380 --> 00:14:39,179 Pulsars are rapidly spinning neutron 398 00:14:39,180 --> 00:14:41,249 stars and they steer up 399 00:14:41,250 --> 00:14:43,229 space time at a constant motion should 400 00:14:43,230 --> 00:14:44,399 just be assigned signal. 401 00:14:44,400 --> 00:14:46,410 So that's our sine wave. 402 00:14:50,200 --> 00:14:51,200 No. 403 00:14:55,730 --> 00:14:58,219 That's a pattern, these are supernova 404 00:14:58,220 --> 00:15:00,319 explosions, can we turn it up a 405 00:15:00,320 --> 00:15:01,320 little? 406 00:15:05,490 --> 00:15:06,490 Supernovas. 407 00:15:10,320 --> 00:15:12,629 Then we have 408 00:15:12,630 --> 00:15:14,340 binary stars in our galaxy. 409 00:15:15,560 --> 00:15:17,629 Orbiting it so many 410 00:15:17,630 --> 00:15:19,069 of them that they will contribute to a 411 00:15:19,070 --> 00:15:20,070 nice. 412 00:15:21,550 --> 00:15:23,679 If binary stars that 413 00:15:23,680 --> 00:15:24,909 much and collide 414 00:15:27,880 --> 00:15:30,169 gone there, and this could 415 00:15:30,170 --> 00:15:32,409 happen with more massive objects like two 416 00:15:32,410 --> 00:15:35,049 black holes orbiting each other 417 00:15:35,050 --> 00:15:36,220 at low frequencies 418 00:15:37,660 --> 00:15:39,939 coming closer and closer 419 00:15:39,940 --> 00:15:40,940 and merging. 420 00:15:44,270 --> 00:15:45,820 That's what we expect to hear 421 00:15:48,080 --> 00:15:50,539 and then we have smaller stars 422 00:15:50,540 --> 00:15:52,669 falling into supermassive black holes, 423 00:15:52,670 --> 00:15:54,949 and this is more of the really 424 00:15:54,950 --> 00:15:56,989 fascinating thing. There is lots and lots 425 00:15:56,990 --> 00:15:58,339 of details to it. 426 00:15:58,340 --> 00:15:58,939 That's another one. 427 00:15:58,940 --> 00:16:00,399 Oh. 428 00:16:04,590 --> 00:16:06,149 You can hear a spin to lining, 429 00:16:07,470 --> 00:16:09,779 you can put out so much physics 430 00:16:09,780 --> 00:16:12,449 out of these signals to get to Mars 431 00:16:12,450 --> 00:16:14,519 and the orbital velocities and all of 432 00:16:14,520 --> 00:16:16,829 that out of these weird noises from 433 00:16:16,830 --> 00:16:19,079 the universe, if we could detect them. 434 00:16:19,080 --> 00:16:20,799 So let's detect them. 435 00:16:22,200 --> 00:16:23,849 We did build gravitational waves, 436 00:16:23,850 --> 00:16:25,919 detectors. We actually started 10, 20 437 00:16:25,920 --> 00:16:27,149 years ago building these. 438 00:16:27,150 --> 00:16:28,679 The two biggest ones are currently in the 439 00:16:28,680 --> 00:16:30,659 United States, one in Louisiana, one in 440 00:16:30,660 --> 00:16:32,039 Washington state. 441 00:16:32,040 --> 00:16:34,769 And that is like the Laser 442 00:16:34,770 --> 00:16:36,239 Interferometer gravitational waves 443 00:16:36,240 --> 00:16:38,909 detector and 444 00:16:38,910 --> 00:16:41,069 basically consists of two big 445 00:16:41,070 --> 00:16:43,739 lasers at a rectangular 446 00:16:43,740 --> 00:16:45,839 four kilometers long. 447 00:16:45,840 --> 00:16:47,879 And when gravitational waves hits the 448 00:16:47,880 --> 00:16:50,429 detector, the distance 449 00:16:50,430 --> 00:16:52,499 of one arm or the length of one arm 450 00:16:52,500 --> 00:16:53,999 will become longer and the other one will 451 00:16:54,000 --> 00:16:55,139 become shorter. 452 00:16:55,140 --> 00:16:57,059 So all we need to do is to measure the 453 00:16:57,060 --> 00:16:59,129 length of the two arms in order 454 00:16:59,130 --> 00:17:01,559 to detect gravitational waves 455 00:17:01,560 --> 00:17:03,179 with only four km long arms. 456 00:17:03,180 --> 00:17:05,159 We need to do that better than the 457 00:17:05,160 --> 00:17:07,229 fraction of an atomic nucleus. 458 00:17:08,869 --> 00:17:10,519 That's why it took us 20 years to build 459 00:17:10,520 --> 00:17:11,520 the thing. 460 00:17:13,930 --> 00:17:16,269 And then last 461 00:17:16,270 --> 00:17:18,189 year, September 14th, I guess 462 00:17:20,680 --> 00:17:22,720 you need not go too far away from here, 463 00:17:24,790 --> 00:17:27,159 last year, September 14th, 464 00:17:27,160 --> 00:17:28,599 gravitational wave hit the detector. 465 00:17:28,600 --> 00:17:31,059 So what happened was we are measuring 466 00:17:31,060 --> 00:17:33,259 the length of both arms with lasers. 467 00:17:33,260 --> 00:17:34,689 We are sending one laser beam to beam 468 00:17:34,690 --> 00:17:36,339 splitter, reflecting it back from 469 00:17:36,340 --> 00:17:38,469 tumorous. And usually 470 00:17:38,470 --> 00:17:40,179 we don't have light at the airport. 471 00:17:40,180 --> 00:17:41,919 But when the gravitational wave changes 472 00:17:41,920 --> 00:17:44,259 the length of both arms, we see a light 473 00:17:44,260 --> 00:17:46,689 flickering at the lower, lower output 474 00:17:46,690 --> 00:17:48,129 on our detector. 475 00:17:48,130 --> 00:17:49,989 So all we need to look for is this 476 00:17:49,990 --> 00:17:51,069 flickering light. 477 00:17:51,070 --> 00:17:53,349 And since full 478 00:17:53,350 --> 00:17:55,419 brightness and no intensity at 479 00:17:55,420 --> 00:17:57,789 all is only like half 480 00:17:57,790 --> 00:17:59,869 of a wavelength, only 500 nanometer 481 00:17:59,870 --> 00:18:01,749 distance, and we cannot only detect full 482 00:18:01,750 --> 00:18:03,969 brightness and zero, we can detect 483 00:18:03,970 --> 00:18:06,429 a little brightness where we can 484 00:18:06,430 --> 00:18:08,799 go all the way down to the fraction 485 00:18:08,800 --> 00:18:11,349 of an atomic nucleus and measuring 486 00:18:11,350 --> 00:18:13,269 the distance variations between the both 487 00:18:13,270 --> 00:18:14,589 arms. 488 00:18:14,590 --> 00:18:16,599 And then the gravitational wave came like 489 00:18:16,600 --> 00:18:18,579 basically a day after we switched on the 490 00:18:18,580 --> 00:18:20,739 device after a big upgrade, a 491 00:18:20,740 --> 00:18:22,959 very beautiful signal. 492 00:18:22,960 --> 00:18:23,960 And here it is. 493 00:18:25,750 --> 00:18:27,400 This is really a simulation. 494 00:18:32,550 --> 00:18:35,159 That is the very first gravitational 495 00:18:35,160 --> 00:18:37,229 wave ever detected 496 00:18:37,230 --> 00:18:40,229 by a gravitational wave detector. 497 00:18:40,230 --> 00:18:41,230 You see? 498 00:18:50,730 --> 00:18:52,499 It wasn't me, it was thousands and 499 00:18:52,500 --> 00:18:53,949 thousands of physicists working at the 500 00:18:53,950 --> 00:18:56,219 thing for 10, 20 years, but 501 00:18:56,220 --> 00:18:58,529 it's it's an amazing discovery. 502 00:18:58,530 --> 00:19:00,209 We know that the prediction of Einstein 503 00:19:00,210 --> 00:19:03,299 was real. What we have here is time 504 00:19:03,300 --> 00:19:04,289 over amplitude. 505 00:19:04,290 --> 00:19:05,579 And you see that this gravitational 506 00:19:05,580 --> 00:19:07,469 waves, we detect, it only lasted for 200 507 00:19:07,470 --> 00:19:08,699 milliseconds. 508 00:19:08,700 --> 00:19:10,469 You also have the frequency. 509 00:19:10,470 --> 00:19:13,079 So the peak frequency was like 250 510 00:19:13,080 --> 00:19:14,219 hertz. 511 00:19:14,220 --> 00:19:16,499 That kind of means that the two objects 512 00:19:16,500 --> 00:19:18,119 orbiting each other, producing this 513 00:19:18,120 --> 00:19:19,889 gravitational waves, had to orbit each 514 00:19:19,890 --> 00:19:22,019 other 250 times a second 515 00:19:22,020 --> 00:19:23,309 that fast. 516 00:19:23,310 --> 00:19:24,599 We don't do this around Sun. 517 00:19:26,730 --> 00:19:28,919 We can also, like, change 518 00:19:28,920 --> 00:19:30,839 the pitch of the signal a little to make 519 00:19:30,840 --> 00:19:31,840 it. 520 00:19:32,130 --> 00:19:34,439 Uh, that didn't look sorry, 521 00:19:34,440 --> 00:19:35,440 Beck. 522 00:19:42,280 --> 00:19:43,280 One more. 523 00:19:45,790 --> 00:19:47,239 We can change the pitch a bit later. 524 00:19:48,850 --> 00:19:49,850 Make it 525 00:19:51,370 --> 00:19:53,769 easier to hear and then you can download 526 00:19:53,770 --> 00:19:55,959 all the raw data from the 527 00:19:55,960 --> 00:19:57,189 Open Science Center. 528 00:19:57,190 --> 00:19:59,199 They also provide Pisin scripts for you 529 00:19:59,200 --> 00:20:01,299 so you can get the raw 530 00:20:01,300 --> 00:20:03,309 data and play with it a little to make it 531 00:20:03,310 --> 00:20:04,959 sound cooler. Many people did music. 532 00:20:04,960 --> 00:20:07,239 Was it actually that was surprising. 533 00:20:07,240 --> 00:20:08,240 Doesn't sound that good. 534 00:20:10,240 --> 00:20:12,279 But what we can do from the data, what 535 00:20:12,280 --> 00:20:14,259 you could actually do with the raw data 536 00:20:14,260 --> 00:20:16,629 is figure out what kind of objects 537 00:20:16,630 --> 00:20:18,219 exactly emitted these gravitational 538 00:20:18,220 --> 00:20:19,179 waves. 539 00:20:19,180 --> 00:20:20,180 So. 540 00:20:22,930 --> 00:20:24,710 The sum of Shiatsus. 541 00:20:31,770 --> 00:20:33,090 Here we go. So 542 00:20:34,560 --> 00:20:36,929 what we found out was 543 00:20:36,930 --> 00:20:38,909 that these gravitational waves were 544 00:20:38,910 --> 00:20:41,009 emitted somewhere 545 00:20:41,010 --> 00:20:42,599 from the direction of the derartu 546 00:20:42,600 --> 00:20:43,600 constellation. 547 00:20:45,920 --> 00:20:48,409 One point three billion light years away 548 00:20:48,410 --> 00:20:50,539 by two black holes, 549 00:20:50,540 --> 00:20:53,029 129 solar masses, the other 550 00:20:53,030 --> 00:20:55,219 34 solar, 36 551 00:20:55,220 --> 00:20:57,319 months, and then 552 00:20:57,320 --> 00:20:59,749 again, we only courts of last 553 00:20:59,750 --> 00:21:01,760 orbit. So this is written here for. 554 00:21:03,390 --> 00:21:05,579 Two black holes more 555 00:21:05,580 --> 00:21:08,189 massive than our sun, orbiting each other 556 00:21:08,190 --> 00:21:09,960 250 times a second 557 00:21:11,730 --> 00:21:13,709 and producing one giant black hole, 558 00:21:15,930 --> 00:21:18,479 liger is actually 559 00:21:18,480 --> 00:21:20,729 tuned to detect these high frequency 560 00:21:20,730 --> 00:21:21,869 gravitational waves. 561 00:21:21,870 --> 00:21:23,999 That's not surprising because 562 00:21:24,000 --> 00:21:26,549 on Earth everything is shaking 563 00:21:26,550 --> 00:21:28,229 at lower frequencies. 564 00:21:28,230 --> 00:21:30,299 So let's take a 565 00:21:30,300 --> 00:21:31,589 car or me walking. 566 00:21:31,590 --> 00:21:32,590 That's a hertz. 567 00:21:33,420 --> 00:21:35,489 So I'm shaking the ground floor 568 00:21:35,490 --> 00:21:37,439 with a hertz, a cloud moving over the 569 00:21:37,440 --> 00:21:39,719 detectors like a few hertz, 570 00:21:39,720 --> 00:21:41,279 attracting one mirror. 571 00:21:41,280 --> 00:21:43,109 Why its gravity and then pulling it to 572 00:21:43,110 --> 00:21:44,069 the other direction. 573 00:21:44,070 --> 00:21:46,499 So all the noise sources on Earth, 574 00:21:46,500 --> 00:21:49,109 ocean waves at the shore 575 00:21:49,110 --> 00:21:51,089 are covering up all the gravitational 576 00:21:51,090 --> 00:21:52,319 waves we could detect at lower 577 00:21:52,320 --> 00:21:53,309 frequencies. 578 00:21:53,310 --> 00:21:55,469 So all the stuff which 579 00:21:55,470 --> 00:21:57,509 is slower than the universe we could 580 00:21:57,510 --> 00:21:59,939 never detect on ground and 581 00:21:59,940 --> 00:22:03,029 like in classic astronomy. 582 00:22:03,030 --> 00:22:04,979 What we can't measure on ground, we 583 00:22:04,980 --> 00:22:07,589 measure in space where there are no cars, 584 00:22:07,590 --> 00:22:09,989 no waves, no clouds, no me walking, 585 00:22:09,990 --> 00:22:12,359 and that is a lesser mission, so. 586 00:22:14,870 --> 00:22:17,089 The extra proposal 587 00:22:17,090 --> 00:22:19,429 for the mission concept is due 588 00:22:19,430 --> 00:22:20,479 in January. 589 00:22:20,480 --> 00:22:22,579 So we are writing the mission proposal 590 00:22:22,580 --> 00:22:25,879 right now and 591 00:22:25,880 --> 00:22:29,179 leaser consists of three spacecraft 592 00:22:29,180 --> 00:22:31,339 that will be launched before 2030 593 00:22:31,340 --> 00:22:33,589 for like 2030, 32 594 00:22:33,590 --> 00:22:35,989 ish, and they will build a giant 595 00:22:35,990 --> 00:22:37,369 laser interferometer in space. 596 00:22:37,370 --> 00:22:39,499 It's like playing Star Wars. 597 00:22:39,500 --> 00:22:42,259 You have three spacecraft separated 598 00:22:42,260 --> 00:22:45,049 by millions of kilometers, 599 00:22:45,050 --> 00:22:46,969 sending lasers back and forth and doing 600 00:22:46,970 --> 00:22:48,889 the very same thing LEGO does. 601 00:22:48,890 --> 00:22:50,179 They measure the distance between 602 00:22:50,180 --> 00:22:52,249 spacecraft and if gravitational wave 603 00:22:52,250 --> 00:22:54,289 passes the constellation, the distance 604 00:22:54,290 --> 00:22:56,419 changes without the satellites moving 605 00:22:56,420 --> 00:22:58,369 and we can detect gravitational waves, 606 00:22:58,370 --> 00:23:00,439 this time at much lower frequency 607 00:23:00,440 --> 00:23:02,389 since a million hertz range. 608 00:23:02,390 --> 00:23:04,309 And the entire constellation is so big, 609 00:23:04,310 --> 00:23:05,989 like two times, three times the diameter 610 00:23:05,990 --> 00:23:07,579 of the sun that we can't have it in 611 00:23:07,580 --> 00:23:08,659 Earth's orbit anymore. 612 00:23:08,660 --> 00:23:10,249 It's trailing the Earth on an orbit 613 00:23:10,250 --> 00:23:11,869 around the Sun. 614 00:23:11,870 --> 00:23:14,059 And you see it up there if you want 615 00:23:14,060 --> 00:23:17,029 your name to be listed on the official 616 00:23:17,030 --> 00:23:19,249 mission concept proposal to 617 00:23:19,250 --> 00:23:20,899 just visit this website, fill out 618 00:23:20,900 --> 00:23:22,369 information like name and your 619 00:23:22,370 --> 00:23:24,649 affiliation, press enter and your name 620 00:23:24,650 --> 00:23:26,179 will be next to names like Stephen 621 00:23:26,180 --> 00:23:28,219 Hawking, who is already supporting us. 622 00:23:28,220 --> 00:23:30,739 So that's like a historic chance 623 00:23:30,740 --> 00:23:32,509 to have your name, it says is a document 624 00:23:32,510 --> 00:23:33,799 that would be nice and we would 625 00:23:33,800 --> 00:23:35,059 appreciate it very much. 626 00:23:35,060 --> 00:23:36,060 Thank you. 627 00:23:37,340 --> 00:23:38,479 Why do we do all that? 628 00:23:38,480 --> 00:23:40,609 Why do you want to detect 629 00:23:40,610 --> 00:23:42,799 gravitational waves where 630 00:23:42,800 --> 00:23:44,869 gravity is the dominating force and the 631 00:23:44,870 --> 00:23:45,870 universe? 632 00:23:47,330 --> 00:23:49,669 Gravity is cool because it's everywhere. 633 00:23:49,670 --> 00:23:52,099 It's not only in stars and neutrinos. 634 00:23:52,100 --> 00:23:54,709 It's not only in the heavy elements. 635 00:23:54,710 --> 00:23:56,809 Gravity is not only emitted 636 00:23:56,810 --> 00:23:59,329 by the free helium and hydrogen 637 00:23:59,330 --> 00:24:00,649 in our universe. 638 00:24:00,650 --> 00:24:02,359 That's the five percent of normal matter 639 00:24:02,360 --> 00:24:03,360 we can see. 640 00:24:04,700 --> 00:24:07,909 Gravity is also emitted by dark matter 641 00:24:07,910 --> 00:24:10,009 stuff we cannot see. 642 00:24:10,010 --> 00:24:11,959 Dark matter is completely invisible to 643 00:24:11,960 --> 00:24:14,299 us, but we know it is there 644 00:24:14,300 --> 00:24:16,459 because it does emit 645 00:24:16,460 --> 00:24:17,749 gravity. 646 00:24:17,750 --> 00:24:19,999 If you look at to have a deep 647 00:24:20,000 --> 00:24:22,099 space, that's an image 648 00:24:22,100 --> 00:24:24,379 taken by habit and you see all 649 00:24:24,380 --> 00:24:25,579 these galaxies. 650 00:24:25,580 --> 00:24:27,829 You also see distortions 651 00:24:27,830 --> 00:24:30,139 like these rings, these arcs, as 652 00:24:30,140 --> 00:24:31,819 if someone put a lens in front of your 653 00:24:31,820 --> 00:24:33,229 picture. 654 00:24:33,230 --> 00:24:35,539 This is gravitational lensing. 655 00:24:35,540 --> 00:24:37,679 These are strong gravitational fields 656 00:24:37,680 --> 00:24:39,859 like curvatures in space time 657 00:24:39,860 --> 00:24:42,049 where light is like curved around 658 00:24:42,050 --> 00:24:43,969 this gravitational field. 659 00:24:43,970 --> 00:24:45,559 And then it's like you have these ghost 660 00:24:45,560 --> 00:24:47,059 images of galaxies which are actually 661 00:24:47,060 --> 00:24:49,219 behind the gravitational field now 662 00:24:49,220 --> 00:24:50,989 seen as arcs. 663 00:24:50,990 --> 00:24:53,059 And by doing data analysis on these 664 00:24:53,060 --> 00:24:54,799 pictures, we can calculate the amount of 665 00:24:54,800 --> 00:24:56,359 gravity in our universe. 666 00:24:56,360 --> 00:24:57,360 That's easy. 667 00:24:58,070 --> 00:25:00,829 Then we can also like count the dots 668 00:25:00,830 --> 00:25:02,689 and get an estimate on the matter and our 669 00:25:02,690 --> 00:25:03,690 universe. 670 00:25:04,340 --> 00:25:05,509 And then we find out 671 00:25:08,990 --> 00:25:10,070 that it does not add up. 672 00:25:11,780 --> 00:25:13,400 There's much more gravity 673 00:25:14,480 --> 00:25:16,309 than death metal. 674 00:25:16,310 --> 00:25:18,619 So very easy solution is 675 00:25:18,620 --> 00:25:20,299 well, there must be some matter. 676 00:25:20,300 --> 00:25:22,789 We can't see some invisible matter. 677 00:25:22,790 --> 00:25:24,289 And this is not the only 678 00:25:26,060 --> 00:25:28,069 the only hint we have that there must be 679 00:25:28,070 --> 00:25:29,659 more matter than we can see. 680 00:25:29,660 --> 00:25:32,030 There are ruban detected. 681 00:25:33,110 --> 00:25:35,269 By observation that spiral 682 00:25:35,270 --> 00:25:38,149 galaxies do not rotate as they should 683 00:25:38,150 --> 00:25:40,009 like. You can calculate the the outer 684 00:25:40,010 --> 00:25:42,109 star orbital velocity from 685 00:25:42,110 --> 00:25:44,179 Spiral Galaxies, how they should be 686 00:25:44,180 --> 00:25:46,339 on the left hand side, but 687 00:25:46,340 --> 00:25:48,649 they actually rotate like they are shown 688 00:25:48,650 --> 00:25:49,650 on the right hand side. 689 00:25:51,280 --> 00:25:53,319 And you can only reproduce, like 690 00:25:53,320 --> 00:25:55,899 theoretically, the right hand curves 691 00:25:55,900 --> 00:25:58,399 by adding more mass to your galaxy. 692 00:25:58,400 --> 00:26:00,339 So spiral galaxies must be much heavier 693 00:26:00,340 --> 00:26:02,049 than we see there. 694 00:26:02,050 --> 00:26:04,359 So there must be more invisible 695 00:26:04,360 --> 00:26:06,229 matter in there. 696 00:26:06,230 --> 00:26:08,289 Again, there's more 697 00:26:08,290 --> 00:26:10,629 gravity than could be explained 698 00:26:10,630 --> 00:26:11,630 with the matter we see. 699 00:26:12,760 --> 00:26:15,159 So we have no idea what documentaries 700 00:26:15,160 --> 00:26:17,049 yet, but we have many ideas. 701 00:26:17,050 --> 00:26:19,209 One idea is there could be 702 00:26:19,210 --> 00:26:21,609 there's a theory that says that could 703 00:26:21,610 --> 00:26:24,519 be an interaction between photons, 704 00:26:24,520 --> 00:26:26,649 normal light particles 705 00:26:26,650 --> 00:26:28,719 and virtual photons 706 00:26:28,720 --> 00:26:31,059 from electric or magnetic fields. 707 00:26:31,060 --> 00:26:32,889 So you have a strong magnetic field, the 708 00:26:32,890 --> 00:26:35,199 VirTra photons in there 709 00:26:35,200 --> 00:26:36,759 and you have a normal photon. 710 00:26:36,760 --> 00:26:39,429 And these two photons may sometimes 711 00:26:39,430 --> 00:26:41,919 on off channels interact 712 00:26:41,920 --> 00:26:44,109 and produce something we call action 713 00:26:44,110 --> 00:26:45,609 or action like particle. 714 00:26:45,610 --> 00:26:48,339 And these axon particles would have 715 00:26:48,340 --> 00:26:51,459 like very similar properties 716 00:26:51,460 --> 00:26:53,569 then what we expect from dark matter, 717 00:26:53,570 --> 00:26:54,909 like they don't interact with anything 718 00:26:54,910 --> 00:26:56,079 else. 719 00:26:56,080 --> 00:26:58,299 And all we need in order to detect them 720 00:26:58,300 --> 00:26:59,799 is another strong magnetic field. 721 00:26:59,800 --> 00:27:01,869 So these actions oscillate back into 722 00:27:01,870 --> 00:27:03,459 photons and then we can detect the 723 00:27:03,460 --> 00:27:05,769 photons there like these solar acción 724 00:27:05,770 --> 00:27:07,269 telescopes out already. 725 00:27:07,270 --> 00:27:09,519 What I am working on right now is another 726 00:27:09,520 --> 00:27:11,319 project. We are building a dark matter 727 00:27:11,320 --> 00:27:12,309 generator. 728 00:27:12,310 --> 00:27:14,389 So this is GPS. 729 00:27:14,390 --> 00:27:15,729 It sounds really cool. 730 00:27:15,730 --> 00:27:18,069 And thanks again. 731 00:27:22,550 --> 00:27:24,289 There are many, many physicists working 732 00:27:24,290 --> 00:27:26,749 on this. It's constructed in D.C., 733 00:27:26,750 --> 00:27:28,849 in Hamburg, but I'm actually working 734 00:27:28,850 --> 00:27:29,749 on Florida on that. 735 00:27:29,750 --> 00:27:30,819 So it's all international. 736 00:27:33,050 --> 00:27:35,149 We are on 100 meter time 737 00:27:35,150 --> 00:27:37,369 scale. We are building a vacuum system 738 00:27:37,370 --> 00:27:39,049 with strong lasers and really strong 739 00:27:39,050 --> 00:27:41,419 magnetic fields, superconducting 740 00:27:41,420 --> 00:27:43,549 magnets. And we want to 741 00:27:43,550 --> 00:27:45,259 have exactly this interaction between 742 00:27:45,260 --> 00:27:47,239 light particles and VirTra photons and 743 00:27:47,240 --> 00:27:49,009 the magnetic field. 744 00:27:49,010 --> 00:27:50,929 Our laser cannot escape the generator, 745 00:27:50,930 --> 00:27:52,699 but the dark matter, if it's generated, 746 00:27:52,700 --> 00:27:55,639 can and will enter our recombination 747 00:27:55,640 --> 00:27:56,539 cavity. 748 00:27:56,540 --> 00:27:58,909 Same device, same magnetic field, 749 00:27:58,910 --> 00:28:01,039 same properties, same resonant 750 00:28:01,040 --> 00:28:03,109 cavity, but this time no 751 00:28:03,110 --> 00:28:04,069 light at all. 752 00:28:04,070 --> 00:28:06,319 But if a dark matter particle enters 753 00:28:06,320 --> 00:28:08,449 there, it is perfectly match 754 00:28:08,450 --> 00:28:10,519 to the cavity and would oscillate back 755 00:28:10,520 --> 00:28:11,809 into light particles. 756 00:28:11,810 --> 00:28:13,549 And then we can detect the light. 757 00:28:13,550 --> 00:28:15,229 And when we switch off our generator and 758 00:28:15,230 --> 00:28:16,729 don't see this light particles anymore, 759 00:28:16,730 --> 00:28:17,809 we know what happened. 760 00:28:17,810 --> 00:28:19,699 We detect the dark matter and the first 761 00:28:19,700 --> 00:28:20,960 place we generated it. 762 00:28:29,110 --> 00:28:30,249 This project is 763 00:28:31,330 --> 00:28:33,399 hopefully finished by 2019, it's 764 00:28:33,400 --> 00:28:35,619 more complex than I showed it to you 765 00:28:35,620 --> 00:28:38,109 again. It's an international effort. 766 00:28:38,110 --> 00:28:40,239 I would like to use my final minute 767 00:28:40,240 --> 00:28:42,369 with the last part of 768 00:28:42,370 --> 00:28:44,439 our universe, which is dark energy. 769 00:28:44,440 --> 00:28:46,599 So dark energy actually makes 770 00:28:46,600 --> 00:28:48,789 up almost 70 percent of everything there 771 00:28:48,790 --> 00:28:50,919 is. What is dark energy and how do 772 00:28:50,920 --> 00:28:51,919 we know it exists? 773 00:28:51,920 --> 00:28:53,289 Again, we can't see it. 774 00:28:53,290 --> 00:28:54,579 You can't really feel it. 775 00:28:54,580 --> 00:28:56,769 But remember, our universe showed 776 00:28:56,770 --> 00:28:58,839 us thirteen point 777 00:28:58,840 --> 00:29:00,669 eight billion years after the Big Bang. 778 00:29:00,670 --> 00:29:02,649 We can measure the speed of acceleration 779 00:29:02,650 --> 00:29:04,839 of the universe and we can actually 780 00:29:04,840 --> 00:29:07,089 see that it's accelerating 781 00:29:07,090 --> 00:29:08,919 in expansion. 782 00:29:08,920 --> 00:29:11,019 So the expansion of the universe is 783 00:29:11,020 --> 00:29:13,449 going faster and faster and faster. 784 00:29:13,450 --> 00:29:15,399 And if something is speeding up, there 785 00:29:15,400 --> 00:29:17,769 must be energy pushing it forward. 786 00:29:17,770 --> 00:29:19,899 And you can calculate pretty easy 787 00:29:19,900 --> 00:29:21,939 actually calculate the amount of energy 788 00:29:21,940 --> 00:29:24,189 necessary to speed up the acceleration 789 00:29:24,190 --> 00:29:26,589 of the universe and that matter. 790 00:29:26,590 --> 00:29:29,049 And this turns out to be equivalent 791 00:29:29,050 --> 00:29:31,349 to 70 percent of all the 792 00:29:31,350 --> 00:29:32,619 and our universe. 793 00:29:32,620 --> 00:29:34,959 And no, we have no idea what dark energy 794 00:29:34,960 --> 00:29:36,039 is or where it come from. 795 00:29:36,040 --> 00:29:37,689 We really don't. And that's like an open 796 00:29:37,690 --> 00:29:39,849 field where come to do research 797 00:29:39,850 --> 00:29:40,850 on that. 798 00:29:41,950 --> 00:29:43,599 The future of the universe actually is 799 00:29:43,600 --> 00:29:46,269 not very bright due to the accelerated 800 00:29:46,270 --> 00:29:48,399 expansion of the universe and the very 801 00:29:48,400 --> 00:29:50,649 end galaxies will be pulled 802 00:29:50,650 --> 00:29:52,839 apart so fast, faster than 803 00:29:52,840 --> 00:29:54,789 the speed of light. Actually, that light 804 00:29:54,790 --> 00:29:56,529 from our neighboring galaxy could not 805 00:29:56,530 --> 00:29:57,530 reach us anymore. 806 00:29:59,470 --> 00:30:01,599 Even faster, our solar system will be 807 00:30:01,600 --> 00:30:03,729 ripped apart because the space 808 00:30:03,730 --> 00:30:06,009 between Earth and Mars is 809 00:30:06,010 --> 00:30:08,229 expanding so fast that 810 00:30:08,230 --> 00:30:10,809 light from Mars cannot reach us anymore. 811 00:30:10,810 --> 00:30:11,950 We will be isolated. 812 00:30:13,390 --> 00:30:15,459 The bonds and our 813 00:30:15,460 --> 00:30:17,589 molecules and our bodies 814 00:30:17,590 --> 00:30:19,239 will be ripped apart because the space 815 00:30:19,240 --> 00:30:21,879 between carbon atoms and oxygen atoms 816 00:30:21,880 --> 00:30:23,559 will expand faster than the speed of 817 00:30:23,560 --> 00:30:24,560 light. 818 00:30:25,030 --> 00:30:27,189 So before we all evaporate and a few 819 00:30:27,190 --> 00:30:29,319 billion of years, remember, 820 00:30:29,320 --> 00:30:30,939 the universe needs you in order to 821 00:30:30,940 --> 00:30:32,049 understand itself. 822 00:30:32,050 --> 00:30:33,050 So. 823 00:30:43,140 --> 00:30:45,359 If you're interested in any 824 00:30:45,360 --> 00:30:47,639 of the projects I showed you, just visit 825 00:30:47,640 --> 00:30:49,319 the different rules of the Lisa Mission 826 00:30:49,320 --> 00:30:51,269 of the legal cooperation of the Dark 827 00:30:51,270 --> 00:30:53,039 Cosmos experiment. 828 00:30:53,040 --> 00:30:55,199 There are so many different 829 00:30:55,200 --> 00:30:57,329 universities doing research on that, and 830 00:30:57,330 --> 00:30:59,219 they all need engineers and physicists 831 00:30:59,220 --> 00:31:01,229 and computer scientists and so on and so 832 00:31:01,230 --> 00:31:03,179 forth. If you have questions, email me or 833 00:31:03,180 --> 00:31:05,339 see me later on the 834 00:31:05,340 --> 00:31:07,079 speaker's culture. 835 00:31:07,080 --> 00:31:08,129 Thank you very much. 836 00:31:08,130 --> 00:31:09,130 Have a great night. 837 00:31:18,990 --> 00:31:19,990 Go, 838 00:31:21,420 --> 00:31:23,519 OK, thank you very much, Simon 839 00:31:23,520 --> 00:31:25,559 Barker s 840 00:31:26,970 --> 00:31:28,889 he already mentioned there will be a 841 00:31:28,890 --> 00:31:32,069 question of arms before, gee, 842 00:31:32,070 --> 00:31:33,659 I would allow a question from the 843 00:31:33,660 --> 00:31:35,520 Internet if there are any. 844 00:31:36,760 --> 00:31:38,189 Yes, there's a question. 845 00:31:38,190 --> 00:31:40,289 It's about the detection of gravitational 846 00:31:40,290 --> 00:31:41,669 waves. 847 00:31:41,670 --> 00:31:44,189 If gravitational waves change spacetime, 848 00:31:44,190 --> 00:31:46,469 does it not also change the detection 849 00:31:46,470 --> 00:31:48,629 device? So we wouldn't detect them at 850 00:31:48,630 --> 00:31:50,349 all? Why does it work? 851 00:31:52,060 --> 00:31:54,449 Well, what basically happens 852 00:31:54,450 --> 00:31:57,329 is that the travel time of light 853 00:31:57,330 --> 00:31:59,489 from the beam splitter to the end 854 00:31:59,490 --> 00:32:00,899 mirror changes. 855 00:32:00,900 --> 00:32:03,059 And yes, everything 856 00:32:03,060 --> 00:32:04,349 in there changes. 857 00:32:04,350 --> 00:32:06,329 The entire device becomes longer and 858 00:32:06,330 --> 00:32:08,069 shorter. But that's exactly what we want 859 00:32:08,070 --> 00:32:09,449 to measure. We want to measure that the 860 00:32:09,450 --> 00:32:11,469 light bounce back and forth. 861 00:32:11,470 --> 00:32:13,169 It's not a little bit faster than in the 862 00:32:13,170 --> 00:32:14,429 other direction. 863 00:32:14,430 --> 00:32:16,709 So we compress entire apparatus and 864 00:32:16,710 --> 00:32:18,599 stretch it when the gravitational waves 865 00:32:18,600 --> 00:32:20,009 pass through. But that's exactly the 866 00:32:20,010 --> 00:32:21,339 effect we are measuring. 867 00:32:23,770 --> 00:32:26,099 OK, that wraps it up for today. 868 00:32:26,100 --> 00:32:28,299 Give another round of applause for 869 00:32:28,300 --> 00:32:29,300 our speaker.