Multiverses _ Wormholes with Brian Cox _ Neil deGrasse Tyson – Cosmic Queries-এর সম্পূর্ণ প্রতিলিপি

00:04:01.349 --> 00:04:09.949 This is a performance with a hugely visually delivered messaging 75 00:04:10.009 --> 00:04:12.770 about science and physics and the universe and yeah. 76 00:04:13.610 --> 00:04:15.669 And uh there's music's a big part of it so 77 00:04:15.689 --> 00:04:19.899 it starts with um Sibelius's fifth symphony the third movement 78 00:04:20.100 --> 00:04:23.399 and uh almost a version of 2001 that I ended 79 00:04:23.519 --> 00:04:25.620 up making because I asked a friend of mine who's 80 00:04:25.660 --> 00:04:27.720 a conductor as a joke one night you know what 81 00:04:27.759 --> 00:04:31.199 said what should Stanley Kubrick have used right and he 82 00:04:31.230 --> 00:04:32.990 was kind of a joke but he immediately said he 83 00:04:33.029 --> 00:04:35.269 should have chosen this piece of music by Sibelius which 84 00:04:35.310 --> 00:04:37.949 was written in 1915. And it's at one level, it's 85 00:04:37.970 --> 00:04:40.709 about swans taking off from a lake in northern Finland. 86 00:04:41.300 --> 00:04:44.019 But at another level, it's about the deep beauty of nature. 87 00:04:44.439 --> 00:04:47.000 It's that idea, that famous quote from Einstein, that if 88 00:04:47.040 --> 00:04:50.160 you look carefully at nature, you might catch a glimpse 89 00:04:50.220 --> 00:04:53.779 of something deeply hidden, which is the structure of nature itself. 90 00:04:54.319 --> 00:04:57.139 And so it just sounded like that to me. So 91 00:04:57.160 --> 00:05:01.810 I ended up almost remaking 2001 in eight minutes, which 92 00:05:01.959 --> 00:05:03.610 to the horror of my promoter. 93 00:05:04.319 --> 00:05:11.110 So let me quantify how popular you are in the UK. 94 00:05:11.449 --> 00:05:13.970 I have a way to measure that for you. I 95 00:05:13.990 --> 00:05:18.410 don't know if I ever told you this. So right 96 00:05:18.490 --> 00:05:23.529 now in the United States, I'd be stopped by 15 97 00:05:23.529 --> 00:05:27.149 out of 20 people in the street, because they'd recognize me, whatever. 98 00:05:28.029 --> 00:05:29.550 I think for you, it's 20 out of 20, or 99 00:05:29.550 --> 00:05:34.709 21 out of 20 people. in the UK, but I 100 00:05:34.730 --> 00:05:39.470 can quantify that, okay? You were so popular there that 101 00:05:39.610 --> 00:05:41.990 no one knows who the hell I am there, so 102 00:05:42.050 --> 00:05:47.560 watch what happened. We were filming Cosmos. We're in Trafalgar Square, 103 00:05:47.920 --> 00:05:52.199 big square, and we're filming Cosmos, and we're cordoned off, okay? 104 00:05:52.899 --> 00:05:55.850 And I'm there, you know, delivering lines and things, and 105 00:05:56.250 --> 00:05:58.860 all manner of people, hey, that's Neil deGrasse Tyson. I said, oh, 106 00:05:58.959 --> 00:06:01.680 where are you from? Oh, we're from the Netherlands. Oh, 107 00:06:01.740 --> 00:06:04.360 we're from India. Oh, we're from Russia. Oh, we're from... 108 00:06:05.180 --> 00:06:12.189 Nobody stops who is from the UK.

Nobody. So either 109 00:06:12.209 --> 00:06:17.430 they're just polite and they don't, or you completely occupy 110 00:06:17.490 --> 00:06:20.740 that space in the UK. And that's what I'm thinking 111 00:06:20.779 --> 00:06:21.420 is going on there. 112 00:06:21.660 --> 00:06:24.259 Or... Brian does all of his talks in the UK, 113 00:06:24.439 --> 00:06:27.079 and instead of ending it with keep looking up, he 114 00:06:27.180 --> 00:06:29.620 ends it with don't listen to Neil deGrasse Tyson. 115 00:06:32.060 --> 00:06:35.540 I'm totally happy, okay, to swap for a few months. 116 00:06:35.939 --> 00:06:39.209 So you can have the UK. I'll have the US 117 00:06:39.230 --> 00:06:42.110 just until the end of this tour. We'll swap roles. 118 00:06:42.149 --> 00:06:44.410 That's a good deal for me. 119 00:06:45.009 --> 00:06:45.769 Here's the question, Brian. 120 00:06:45.790 --> 00:06:47.610 I can't even recite this many cities in the UK 121 00:06:47.649 --> 00:06:49.670 that you're going to do here. In the United States. 122 00:06:49.930 --> 00:06:51.970 You know what this feels like? A little bit. Because 123 00:06:51.990 --> 00:06:54.129 you've got that Beatles haircut. It feels a little bit 124 00:06:54.149 --> 00:06:56.610 like the British invasion, you know? Putting us in a 125 00:06:56.629 --> 00:06:59.060 new place that we didn't even know we could land. 126 00:06:59.139 --> 00:07:03.399 Nothing wrong with that. Yeah, nothing wrong with that. Very cool. So, Chuck, 127 00:07:03.459 --> 00:07:06.019 you collected questions from our Patreon supporters. 128 00:07:06.100 --> 00:07:10.829 Indeed, we do have them. And, of course, you know, 129 00:07:11.050 --> 00:07:15.920 our listeners are very excited. to ask Brian questions. So 130 00:07:15.939 --> 00:07:17.120 do you want to jump into this? 131 00:07:17.279 --> 00:07:19.480 Yeah, let's go straight ahead. What do you have? 132 00:07:19.500 --> 00:07:28.089 All right, this is Marcus Gustafsson, who says, hello and 133 00:07:28.209 --> 00:07:32.089 greetings from Sweden. If the strength of gravity happened to 134 00:07:32.129 --> 00:07:35.649 be a little stronger or a little bit weaker than 135 00:07:35.689 --> 00:07:40.569 it is, how different would our universe be? 136 00:07:42.329 --> 00:07:45.470 It's a good question and it's this is widely debated 137 00:07:45.550 --> 00:07:49.129 actually because um there's a question of how much you 138 00:07:49.149 --> 00:07:52.290 can change the the fundamental properties of nature so do 139 00:07:52.310 --> 00:07:54.029 you say the strength of gravity the mass of the 140 00:07:54.089 --> 00:07:57.089 electron the way the higgs field works all those things 141 00:07:57.550 --> 00:08:00.529 such that you have a radically different universe and actually 142 00:08:00.550 --> 00:08:03.360 it's quite hard because you can change some things and 143 00:08:03.379 --> 00:08:05.519 then change something else and it kind of balances the 144 00:08:05.560 --> 00:08:08.579 change out and and so it's quite a controversial area 145 00:08:08.660 --> 00:08:13.870 actually but Broadly speaking, if gravity were too strong, all 146 00:08:13.949 --> 00:08:17.610 else being equal, then things would collapse ultimately into black 147 00:08:17.629 --> 00:08:20.430 holes very quickly. So the early universe would not have 148 00:08:20.490 --> 00:08:26.420 formed extended structures like galaxies and solar systems, or stars 149 00:08:26.459 --> 00:08:29.720 may be very short-lived and so on. So you can 150 00:08:30.500 --> 00:08:32.320 change the universe such that you would not have life 151 00:08:32.379 --> 00:08:34.559 in the universe if you increase the strength of gravity 152 00:08:34.600 --> 00:08:37.100 too much. But also you can decrease it too much, 153 00:08:37.159 --> 00:08:39.679 and then stars and galaxies don't form in the early universe. 154 00:08:40.610 --> 00:08:45.059 you probably don't have a living universe. Now, the complication 155 00:08:45.120 --> 00:08:47.340 comes when you say, okay, well, what if in the 156 00:08:47.379 --> 00:08:52.559 early universe the slightly over-dense regions were a bit denser, 157 00:08:52.879 --> 00:08:55.700 which would have something to do with a theory we 158 00:08:55.720 --> 00:08:59.049 called inflation, possibly, or something the way the Big Bang was, 159 00:08:59.690 --> 00:09:01.690 and then you turn gravity down a bit. Can you 160 00:09:01.750 --> 00:09:04.429 kind of compensate? And it's true, you can. So it 161 00:09:04.470 --> 00:09:08.759 becomes an extremely difficult modelling challenge And so you'll see 162 00:09:08.899 --> 00:09:11.139 research papers on this. How can you change the things 163 00:09:11.179 --> 00:09:14.159 and fine tune things? But then broadly speaking, that's what happens. 164 00:09:14.200 --> 00:09:17.340 If it is too strong, then everything collapses into black holes. 165 00:09:17.419 --> 00:09:20.200 And if it is too weak, nothing forms at all. 166 00:09:20.360 --> 00:09:23.710 So that's the physicist answer. Okay. Now we'll give you 167 00:09:23.730 --> 00:09:25.039 the astrophysicist answer. 168 00:09:25.179 --> 00:09:27.409 All right. 169 00:09:27.590 --> 00:09:34.289 In graduate astrophysics 101, okay, one of the first calculations 170 00:09:34.330 --> 00:09:37.639 we do is, What happens to the luminosity of a 171 00:09:37.700 --> 00:09:43.899 star if you change the gravitational constant? It's a calculation 172 00:09:43.940 --> 00:09:47.409 we do. So what you do is you put a 173 00:09:47.419 --> 00:09:50.830 little parameter there and see what happens to that parameter 174 00:09:50.929 --> 00:09:54.309 as you run through the calculations for a star's luminosity. 175 00:09:54.549 --> 00:09:57.850 And what you find is that the luminosity of a 176 00:09:57.909 --> 00:10:02.759 star is extremely small. sensitive to the value of Newton's 177 00:10:02.799 --> 00:10:10.440 gravitational constant, to the seventh power. So what's

interesting about 178 00:10:10.480 --> 00:10:15.700 that is if the gravitational constant were different, slightly higher 179 00:10:15.879 --> 00:10:19.899 earlier in the universe than today, As Brian can attest, 180 00:10:19.919 --> 00:10:23.830 there are whole branches of physics that think about and 181 00:10:23.879 --> 00:10:27.389 wonder and worry about whether the constants have actually been constant. 182 00:10:28.750 --> 00:10:31.909 Forget whether we have godlike powers to just change it 183 00:10:31.950 --> 00:10:34.490 and see what happens. Were they always this good? Did 184 00:10:34.570 --> 00:10:38.429 they change over time? So you can look at how 185 00:10:38.610 --> 00:10:41.889 sensitive it is and constrain how much it could have 186 00:10:41.970 --> 00:10:47.429 possibly changed because you would see stars of enormous luminosities 187 00:10:48.059 --> 00:10:50.639 living out their lives very quickly in the early universe, 188 00:10:50.700 --> 00:10:54.419 and you don't see that. So it's to the seventh 189 00:10:54.500 --> 00:10:58.919 power of that term that the luminosity would be affected. 190 00:10:59.019 --> 00:11:01.580 And seventh power is that times that times that times 191 00:11:01.620 --> 00:11:05.450 that times that, okay, all through. So we actually find 192 00:11:05.490 --> 00:11:09.129 that number in intro astrophysics graduate school. 193 00:11:09.470 --> 00:11:12.730 And can you define luminosity for me? Because if you're 194 00:11:12.769 --> 00:11:15.029 saying that it's not just brightness. 195 00:11:15.110 --> 00:11:17.690 Oh, yeah, yeah, yeah. So here it is. It's simple luminosity. 196 00:11:19.669 --> 00:11:23.970 This example is rapidly becoming obsolete, but take a 100-watt 197 00:11:24.009 --> 00:11:28.350 light bulb, okay? Yeah, well, yeah. Okay, what is that, right? Yeah, exactly. 198 00:11:28.370 --> 00:11:29.980 In the old days, there was like the bulb. 199 00:11:30.000 --> 00:11:32.559 That's like, okay, now here's what you do first. You 200 00:11:32.600 --> 00:11:34.419 dial up your grandmother on a rotary phone. 201 00:11:38.820 --> 00:11:41.519 So the wattage is its luminosity. So no matter what 202 00:11:41.639 --> 00:11:43.820 distance I put it from you, it will always be 203 00:11:43.840 --> 00:11:44.539 a 100-watt bulb. 204 00:11:44.620 --> 00:11:45.279 Okay, gotcha. 205 00:11:45.909 --> 00:11:47.990 As I get it farther away, it gets dimmer and 206 00:11:48.009 --> 00:11:50.049 dimmer and dimmer, so that would be its brightness. That's all. 207 00:11:50.110 --> 00:11:52.470 So that's it, so okay. So you're saying that gravity 208 00:11:52.509 --> 00:11:56.629 is like a string on the light itself, kind of 209 00:11:56.669 --> 00:11:58.889 like that would be making it less? 210 00:11:59.309 --> 00:12:00.750 No, no, it would be like a knob. 211 00:12:00.850 --> 00:12:02.409 Like a knob turning it down. Increase the wattage. 212 00:12:02.429 --> 00:12:03.169 Thank you, right. 213 00:12:03.269 -->

00:12:05.590 So instead of pulling it back, it's turning down the wattage. Okay, 214 00:12:05.629 --> 00:12:06.350 that's cool, man. 215 00:12:06.429 --> 00:12:09.529 Yeah, it's a dimmer or a thing on the bulb itself. Yeah, 216 00:12:09.840 --> 00:12:12.100 let's make the universe sexy, baby. You know? 217 00:12:12.259 --> 00:12:16.340 Let's dim the lights, hey, you know. How would you 218 00:12:16.379 --> 00:12:18.070 like a little cosmic champagne? 219 00:12:20.789 --> 00:12:23.049 All right. Time to go to the next question. That's 220 00:12:23.090 --> 00:12:24.090 how you know. 221 00:12:24.629 --> 00:12:25.350 I'm enjoying this. 222 00:12:26.629 --> 00:12:28.289 You like the sexy universe, Brian? 223 00:12:28.450 --> 00:12:31.840 Yeah. I'm going to use some. I'm making notes. 224 00:12:33.240 --> 00:12:38.820 All right. Let's go to Sandra Bayani. And Sandra says, 225 00:12:39.360 --> 00:12:43.049 is it possible that the laws of physics change beyond 226 00:12:43.090 --> 00:12:46.350 our cosmic horizons so that all of our theories about 227 00:12:46.409 --> 00:12:51.610 multiverses stop working and stop making sense. Greetings, fellow Earthling. 228 00:12:51.629 --> 00:12:56.549 I cannot get enough of this show. Please, whatever you do, 229 00:12:57.169 --> 00:12:59.360 never stop this podcast. 230 00:12:59.960 --> 00:13:01.759 Oh, Chuck, did you just add that? 231 00:13:01.820 --> 00:13:04.480 No, I didn't. I really didn't. 232 00:13:06.100 --> 00:13:07.779 I mean, I love that question. 233 00:13:07.799 --> 00:13:08.440 Yeah, that's wonderful. 234 00:13:08.539 --> 00:13:10.360 I love that question because it brings in our horizon 235 00:13:10.399 --> 00:13:13.500 and multiverses and the very theories that predict a multiverse. 236 00:13:13.919 --> 00:13:15.960 work in our universe, why should they work in another? 237 00:13:16.259 --> 00:13:17.820 We're going to take a break, and when we come back, 238 00:13:18.139 --> 00:13:19.779 we will get right to the heart of that question 239 00:13:20.059 --> 00:13:22.539 with our special guest today. He's a special guest to me, 240 00:13:22.980 --> 00:13:26.039 Brian Cox from over in the UK. We'll be right back. 241 00:13:28.570 --> 00:13:32.809 We're back, StarTalk Cosmic Queries. This is everything physics, because 242 00:13:32.870 --> 00:13:35.409 I got one of my people here, one of my 243 00:13:37.309 --> 00:13:41.629 science and education brethren, Brian Cox from over in the UK, 244 00:13:42.190 --> 00:13:45.840 who They call him a rock star over there, and 245 00:13:45.879 --> 00:13:48.169 we've said this on his previous appearances, but it's worth 246 00:13:48.629 --> 00:13:52.870 repeating that this man had a number one song on 247 00:13:52.909 --> 00:13:56.649 the pop charts in the UK. So you're a literal 248 00:13:56.809 --> 00:14:00.990 and figurative rock star of science. Have I overstated that, Brian? 249 00:14:01.009 --> 00:14:03.389 No, I think you've understated it, if anything. 250 00:14:08.000 --> 00:14:09.820 So what was the name of the song again that 251 00:14:09.860 --> 00:14:10.480 you performed? 252 00:14:10.990 --> 00:14:12.909 The most famous song is a song called Things Can 253 00:14:12.970 --> 00:14:17.000 Only Get Better, which you will say correctly runs counter 254 00:14:17.009 --> 00:14:18.320 to the second law of thermodynamics. 255 00:14:18.460 --> 00:14:18.960 Oh, yes. 256 00:14:19.659 --> 00:14:22.019 So it's an inaccurate song, but yeah. 257 00:14:23.019 --> 00:14:25.220 Yeah, sometimes you got to break some eggs to make 258 00:14:25.259 --> 00:14:27.019 an omelet, you know, as they say. 259 00:14:27.659 --> 00:14:27.919 All right. 260 00:14:28.080 --> 00:14:30.590 So Chuck, we left off with a brilliant question about 261 00:14:31.090 --> 00:14:32.850 here we are in our universe that has our own 262 00:14:32.889 --> 00:14:34.549 horizon and we come up with our own theories of 263 00:14:34.570 --> 00:14:36.870 the universe. And one of them is that there might 264 00:14:36.909 --> 00:14:39.889 be a multiverse. So beyond our horizon, if it's not 265 00:14:39.929 --> 00:14:42.669 in our universe, Why should we even believe that the 266 00:14:42.720 --> 00:14:45.820 rules that predict a multiverse would even exist? There you go. 267 00:14:45.860 --> 00:14:46.740 I love that. 268 00:14:46.759 --> 00:14:50.200 There's a lot to unpick there. So our horizon, first 269 00:14:50.240 --> 00:14:52.580 of all, there is a limit to how far we 270 00:14:52.600 --> 00:14:56.240 can see, which is the fact that our universe is 271 00:14:56.320 --> 00:14:59.090 of a finite age, or let's say there's been 13.8 272 00:14:59.090 --> 00:15:01.769 billion years since the Big Bang. And so there's a 273 00:15:01.870 --> 00:15:04.450 finite distance you can see because light travels at a 274 00:15:04.490 --> 00:15:08.779 finite speed. So we are very sure that that there 275 00:15:08.799 --> 00:15:12.779 are galaxies way beyond our horizon, but essentially the light 276 00:15:12.799 --> 00:15:15.899 has not had time to reach us from them. Now, actually, 277 00:15:15.919 --> 00:15:17.899 as Neil said in the answer to the last question, 278 00:15:18.539 --> 00:15:22.320 you can say, well, observationally, do we see any evidence 279 00:15:22.460 --> 00:15:25.350 of the laws of nature? So the strength of gravity, 280 00:15:25.379 --> 00:15:28.539 for example, going back to the last question, changing as 281 00:15:28.590 --> 00:15:31.190 we look out to the most distant galaxies. And the 282 00:15:31.230 --> 00:15:34.230 answer is no. We have no evidence that they change 283 00:15:34.570 --> 00:15:36.809 in the patch of the universe we can see. So 284 00:15:36.830 --> 00:15:39.850 that's the observational point. But when you start to talk 285 00:15:39.870 --> 00:15:42.789 about the laws of nature in different regions of the universe, 286 00:15:42.820 --> 00:15:46.820 our multiverse, as you said, then it becomes more interesting. 287

00:15:47.960 --> 00:15:50.600 One multiverse, there are lots of different kinds of multiverse, 288 00:15:50.700 --> 00:15:53.419 but one of them is called the inflationary multiverse. So 289 00:15:53.440 --> 00:15:57.669 we have a theory called eternal inflation, which essentially leads 290 00:15:57.789 --> 00:16:00.710 to the idea that there are perhaps an infinite number 291 00:16:00.789 --> 00:16:04.690 of bubble universes of which ours is one. And the 292 00:16:04.950 --> 00:16:07.960 piece that we can see, the observational piece, The little 293 00:16:07.980 --> 00:16:10.320 piece we can observe is a patch in one bubble 294 00:16:10.379 --> 00:16:13.559 universe amongst perhaps an infinite number of bubble universes in 295 00:16:13.580 --> 00:16:18.539 the inflationary multiverse. And those theories do lend themselves, potentially, 296 00:16:19.759 --> 00:16:23.870 to the laws of nature in each bubble possibly being different. 297 00:16:24.269 --> 00:16:26.450 And the way I sometimes picture it is like a 298 00:16:26.490 --> 00:16:32.049 snowstorm with snowflakes. So every snowflake is different because it's 299 00:16:32.070 --> 00:16:35.730 had a different formation history. But there's something similar about 300 00:16:35.769 --> 00:16:38.769 them all. which goes to the underlying structure, which is 301 00:16:38.809 --> 00:16:42.029 to do with the water molecule itself. So there's something similar. 302 00:16:42.049 --> 00:16:46.870 There's an underlying framework, but every snowflake is different. And 303 00:16:46.889 --> 00:16:49.889 the inflationary multiverse can be like that. So you can 304 00:16:49.950 --> 00:16:53.320 imagine that the laws we see, things like the strength 305 00:16:53.360 --> 00:16:57.639 of gravity, sort of crystallize out as these bubble universes 306 00:16:57.740 --> 00:17:02.620 form from the potential, which is this thing called inflation 307 00:17:02.659 --> 00:17:05.980 that's potentially going on all the time. So it's possible. 308 00:17:06.440 --> 00:17:11.539 that different universes have different emergent laws, things like the 309 00:17:11.559 --> 00:17:16.829 strength of gravity. I think most physicists probably all expect 310 00:17:16.869 --> 00:17:20.750 that there'll be some kind of underlying framework, which could, 311 00:17:21.069 --> 00:17:22.869 something that we don't know what it is, right? Something 312 00:17:22.890 --> 00:17:26.109 like string theory or something, which underlies the whole thing. 313 00:17:26.750 --> 00:17:29.970 So that, maybe Neil wants to add, but that's my 314 00:17:30.029 --> 00:17:31.509 summary of the inflationary multiverse. 315 00:17:32.019 --> 00:17:37.460 I love your snowflake analogy, but suppose that, Do you 316 00:17:37.500 --> 00:17:45.119 have enough latitude in your eternal inflationary multiverse model to 317 00:17:45.619 --> 00:17:49.200 have a universe that has five-pointed snowflakes instead of six? 318 00:17:49.859 --> 00:17:52.440 I mean, how much room do you have to just 319 00:17:53.039 --> 00:17:55.200 make stuff up completely? 320 00:17:56.369 --> 00:17:59.309 We don't know. This goes back. It links to something 321 00:17:59.349 --> 00:18:02.390 called the string landscape, which Leonard Susskind actually wrote a 322 00:18:02.410 --> 00:18:05.349 great book called The Cosmic Landscape a while ago detailing 323 00:18:05.390 --> 00:18:07.299 this theory. So when you look at string theory. 324 00:18:07.319 --> 00:18:09.140 Just remind me, Leonard Susskind is the one who's a 325 00:18:09.180 --> 00:18:13.529 big exponent of the holographic universe. That's the same guy. 326 00:18:13.549 --> 00:18:17.029 Yeah, he's been at the cutting edge of physics for decades, 327 00:18:17.109 --> 00:18:21.509 raising it. So in the string landscape, the idea is 328 00:18:21.589 --> 00:18:25.650 that in string theory, it turns out you can have... 329 00:18:25.970 --> 00:18:28.119 There's a number that they calculate. I don't know how 330 00:18:28.160 --> 00:18:29.700 they do it, actually, but it's something... Well, I do 331 00:18:29.720 --> 00:18:31.180 know how they do it. It's something to do with 332 00:18:31.220 --> 00:18:33.299 all the extra dimensions being curled up and stuff. It 333 00:18:33.319 --> 00:18:37.740 doesn't matter. but essentially 10 to the power 500 different possibilities. 334 00:18:38.700 --> 00:18:41.539 So one with 500 noughts after it. These are the 335 00:18:41.599 --> 00:18:46.039 different ways that you can produce laws of physics like 336 00:18:46.059 --> 00:18:49.180 the ones we see from the underlying theory. And that 337 00:18:49.200 --> 00:18:50.980 was seen as a really disappointing. 338 00:18:51.009 --> 00:18:53.180 That's a lot of wiggle room right there. 339 00:18:53.269 --> 00:18:55.809 But the way I see it, it's almost like saying 340 00:18:56.490 --> 00:18:59.509 we understand DNA. So in biology, we have a theory, 341 00:18:59.549 --> 00:19:02.319 we have these things, A, C, D, T, and G. 342 00:19:02.940 --> 00:19:05.460 the four different bases that come together to form DNA. 343 00:19:06.259 --> 00:19:08.259 And it's like saying, okay, so there's an underlying theory. 344 00:19:08.299 --> 00:19:12.480 It's pretty simple. It's the double helix. It's chemistry. Out 345 00:19:12.559 --> 00:19:16.480 of that, it's like saying, right, predict a human being. So, 346 00:19:16.509 --> 00:19:20.109 of course, you can't because there are many different combinations 347 00:19:20.190 --> 00:19:22.910 of DNA. And we have no understanding yet of which 348 00:19:23.029 --> 00:19:25.089 ones would work and which ones wouldn't and which ones 349 00:19:25.130 --> 00:19:27.289 can be realized by evolution and which ones can't. 350 00:19:27.470 --> 00:19:32.029 It's an astronomical number of combinations of just to make 351 00:19:32.089 --> 00:19:34.380 humans let alone all forms of life. 352 00:19:34.759 --> 00:19:38.240 So it's like saying we understand the basic chemistry that

353 00:19:38.339 --> 00:19:43.289 gives us that thing, DNA. But then from that, predicting 354 00:19:43.329 --> 00:19:47.210 a particular instance of that, an organism, is of course, 355 00:19:47.250 --> 00:19:50.259 it depends on its history. It depends on all sorts 356 00:19:50.299 --> 00:19:51.880 of things, and it's the same. 357 00:19:52.519 --> 00:19:55.140 If you look at that like, I don't know, an 358 00:19:55.319 --> 00:20:00.440 alphabet to create a language, can you rule out the nonsense? 359 00:20:00.539 --> 00:20:05.339 For instance, if you know English, you know that HLPPP500. 360 00:20:06.779 --> 00:20:10.480 It's not a word. Right? 361 00:20:10.549 --> 00:20:13.269 So are you able to kind of rule out the 362 00:20:13.349 --> 00:20:18.130 nonsense that, okay, these things would not happen. And so 363 00:20:18.609 --> 00:20:20.910 even though it is a possible combination, we know that 364 00:20:20.970 --> 00:20:24.150 it's kind of gibberish. How do we narrow that? 365 00:20:25.519 --> 00:20:28.259 Well, I mean, we don't. We don't know. We haven't 366 00:20:28.299 --> 00:20:30.559 got the expertise. We don't really know what the underlying 367 00:20:30.640 --> 00:20:33.759 theory is. But I mean, for example, you could imagine 368 00:20:34.099 --> 00:20:38.450 a bubble universe that forms and Gravity is so strong 369 00:20:39.450 --> 00:20:42.500 that it just collapses again in a millisecond. There may 370 00:20:42.539 --> 00:20:45.839 be many universes like that. So that might be, as 371 00:20:45.859 --> 00:20:47.640 you say, that might be a universe that we consider 372 00:20:47.680 --> 00:20:50.849 was just never got going. So it's undoubtedly true. 373 00:20:50.869 --> 00:20:51.910 That's a gibberish universe. 374 00:20:51.930 --> 00:20:54.130 That would be a gibberish universe, maybe. So it might 375 00:20:54.210 --> 00:20:57.750 just about form and then collapse again, for example. 376 00:20:58.309 --> 00:21:00.650 You'll know if you meet a life form from there 377 00:21:00.670 --> 00:21:05.440 because it's just like. 378 00:21:08.339 --> 00:21:10.720 Not only are the laws of physics gibberish, so is 379 00:21:10.759 --> 00:21:12.200 their language, right? That's what you're saying. 380 00:21:13.099 --> 00:21:16.210 I just want to emphasize, this is speculative stuff. So 381 00:21:16.230 --> 00:21:18.490 the string landscape, as I said, Leonard Susskind's book is 382 00:21:18.509 --> 00:21:22.119 great on this. And then the link, though, It's interesting 383 00:21:22.140 --> 00:21:24.900 that inflation, which Neil will know about as well, that's 384 00:21:24.960 --> 00:21:28.750 a theory that was introduced initially just to deal with 385 00:21:28.789 --> 00:21:31.569 something called the horizon problem. You mentioned the horizon. It's 386 00:21:31.589 --> 00:21:37.170 essentially the unexplained point that if you look in one 387 00:21:37.210 --> 00:21:39.250 direction out into the universe as far as you can, 388 00:21:39.569 --> 00:21:41.450 and then turn around and look in the other direction, 389 00:21:42.069 --> 00:21:45.819 then you're looking at points that emitted light that we're 390 00:21:45.839 --> 00:21:49.690 receiving now, that now... in the universe is something like 391 00:21:49.690 --> 00:21:52.329 93 billion, I think it is light years away, right? 392 00:21:52.349 --> 00:21:54.410 Because of the expansion of the universe. So you're looking 393 00:21:54.450 --> 00:21:56.970 at points that in the standard model of things could 394 00:21:57.069 --> 00:21:59.980 never have been in contact with each other and yet 395 00:22:00.039 --> 00:22:03.420 are at the same temperature. So one part in 100,000, 396 00:22:03.420 --> 00:22:06.500 which is an observation. So that means, and inflation is 397 00:22:06.519 --> 00:22:06.940 initially- Just a. 398 00:22:06.900 --> 00:22:09.119 Quick thing, Chuck, I think we did an explainer on this. 399 00:22:10.140 --> 00:22:13.430 There was something where I was talking about that the 400 00:22:13.470 --> 00:22:17.799 universe has a more uniform temperature than- Different parts of 401 00:22:17.839 --> 00:22:19.099 the same room you're in. 402 00:22:19.160 --> 00:22:19.339 Right. 403 00:22:19.519 --> 00:22:22.200 Well, that's because with that explainer, we were talking about 404 00:22:22.700 --> 00:22:25.220 redshifting is kind of how we got into it. 405 00:22:25.500 --> 00:22:26.960 Oh, that's how we got there. Because I was saying 406 00:22:26.980 --> 00:22:28.819 you have an air conditioner in a corner, you have 407 00:22:28.849 --> 00:22:31.170 a heater over there, and you're fine if it's a 408 00:22:31.210 --> 00:22:35.529 five-degree range in a room that's talking to itself thermodynamically. 409 00:22:36.009 --> 00:22:38.930 And now we have across the whole freaking universe, and 410 00:22:38.970 --> 00:22:43.299 it's within 100,000th of a degree, which is completely mind-boggling freaky. 411 00:22:43.619 --> 00:22:45.319 And we needed a freaky explanation for it. 412 00:22:45.319 --> 00:22:48.519 Yeah. So inflation was the idea that once upon a 413 00:22:48.559 --> 00:22:52.400 time they were in contact. And then the universe expanded very, very, very, 414 00:22:52.440 --> 00:22:56.460 very fast for probably a small amount of time. And 415 00:22:56.880 --> 00:23:00.000 so we thought that they couldn't have been in contact 416 00:23:00.400 --> 00:23:02.619 with each other. But in fact, they were. And so 417 00:23:02.640 --> 00:23:07.250 that's why inflation was introduced. But it ended up doing 418 00:23:07.289 --> 00:23:09.970 several things that it was not designed to do initially. 419 00:23:10.390 --> 00:23:13.519 One was that the thing that drives inflation which has 420 00:23:13.539 --> 00:23:15.700 got a fancy name called the inflating field, but it 421 00:23:15.720 --> 00:23:16.460 doesn't matter what it is. 422 00:23:16.460 --> 00:23:19.220 It's a breakdown in the supply chain. 423 00:23:19.460 -->

00:23:26.539 Oh, it makes that look trivial. Two points were doubling in, 424 00:23:26.799 --> 00:23:28.619 if you take the two points in the universe, then 425 00:23:28.640 --> 00:23:31.009 they double, the distance between them doubled every 10 to 426 00:23:31.029 --> 00:23:35.210 the minus 37 seconds in the basic models of inflation. 427 00:23:35.230 --> 00:23:37.670 So it's much worse than we're going through now with prices. 428 00:23:37.750 --> 00:23:39.809 It's an exponential expansion. 429 00:23:41.920 --> 00:23:44.349 Much worse is an understatement there, just to be clear. 430 00:23:44.589 --> 00:23:49.170 But in looking at that, Stephen Hawking actually was involved 431 00:23:49.210 --> 00:23:52.089 in this, and many physicists in the 80s found that 432 00:23:52.450 --> 00:23:53.029 these theories. 433 00:23:53.049 --> 00:23:56.009 Chuck, Chuck, last time we did this, he said, Stephen was. 434 00:23:55.970 --> 00:23:59.779 Involved in this. He's cleaning it up this time, Neil. 435 00:23:59.819 --> 00:24:01.819 He's been a little better. 436 00:24:02.099 --> 00:24:03.380 A name drop. 437 00:24:03.859 --> 00:24:05.319 We got to hear the last name here. 438 00:24:05.339 --> 00:24:07.480 Stephen, Kip, Lenny, all those people. 439 00:24:07.519 --> 00:24:08.119 This time. 440 00:24:08.980 --> 00:24:13.930 So that theory was discovered, predicted, that there would be 441 00:24:14.009 --> 00:24:17.970 ripples in the density of particles in the universe through 442 00:24:17.990 --> 00:24:20.750 the Big Bang as inflation drew to a close, which 443 00:24:20.869 --> 00:24:23.890 are the ripples that we see in the cosmic microwave 444 00:24:23.930 --> 00:24:26.809 background radiation, which you may have talked about, and also 445 00:24:26.849 --> 00:24:30.490 actually in the distribution of galaxies across the sky. So 446 00:24:30.509 --> 00:24:33.779 there's a distribution. They're not just completely random across the sky. 447 00:24:33.799 --> 00:24:37.480 There are patterns in the galactic distribution. And that was 448 00:24:37.539 --> 00:24:40.700 predicted before it was observed by this theory. So the 449 00:24:40.720 --> 00:24:44.599 theory is interesting. And textbook, you'll find it in cosmology textbooks. 450 00:24:44.900 --> 00:24:47.359 But the eternal inflation bit, which is kind of an 451 00:24:47.400 --> 00:24:50.539 add-on to that, ends up with this idea that inflation 452 00:24:50.579 --> 00:24:53.140 doesn't stop everywhere at the same time, basically. So you 453 00:24:53.160 --> 00:24:57.319 get multiple bubble universes. And then that theory was noticed 454 00:24:57.539 --> 00:25:01.160 that that's a mechanism to realize the string landscape. which 455 00:25:01.220 --> 00:25:03.619 gives you the possibility of varying the laws of nature 456 00:25:03.640 --> 00:25:05.759 in each of those bubbles. So that was the history. 457 00:25:05.940 --> 00:25:08.240 So it's not just, it sounds fantastical, but it's not 458 00:25:08.279 -->

00:25:10.920 just like somebody just dreamt it up one day and 459 00:25:10.940 --> 00:25:11.509 said this would be cool. 460 00:25:11.529 --> 00:25:13.529 I try to make that clear because otherwise they think 461 00:25:13.549 --> 00:25:16.170 we're just pulling stuff out of our ass. And it's, 462 00:25:17.109 --> 00:25:18.329 even if it is out of our ass, it's very 463 00:25:18.369 --> 00:25:19.470 carefully withdrawn. 464 00:25:20.309 --> 00:25:22.549 By the way, that's one of the universes. 465 00:25:23.009 --> 00:25:23.250 Yeah. 466 00:25:28.450 --> 00:25:30.829 With a central black hole. Time to go to the 467 00:25:30.869 --> 00:25:32.099 next question. Oh, no. 468 00:25:32.410 --> 00:25:35.019 Time to go to the next question. 469 00:25:35.039 --> 00:25:40.940 Okay, here we go. Hitty Wagemans says this. Hello, Dr. 470 00:25:41.000 --> 00:25:41.940 Tyson, Dr. 471 00:25:42.000 --> 00:25:45.809 Cox, and Lord Nice, and I bet you can't pronounce 472 00:25:45.910 --> 00:25:51.759 my name correctly. You win that bet, all right? Get 473 00:25:51.799 --> 00:25:52.680 no argument from me. 474 00:25:53.440 --> 00:25:55.799 And the name is what? 475 00:25:56.220 --> 00:26:06.990 His name is H-I-D-D-E-W-A-A-G-E-M-A-N-S. I said Hiddy Wigmans. And he's 476 00:26:07.029 --> 00:26:10.069 from the Netherlands, so he's Dutch. It's a Dutch name. 477 00:26:10.109 --> 00:26:13.700 That helps how to pronounce that, yeah. He de Wegmans, maybe. 478 00:26:13.839 --> 00:26:20.259 He de Wegmans, okay. Yes, if it's Dutch, it's... He says, 479 00:26:20.319 --> 00:26:24.150 I'm asking myself after I watch the movie, The Atom Project, 480 00:26:24.930 --> 00:26:29.329 if you really can time travel with wormholes. By the way, oh, 481 00:26:30.009 --> 00:26:35.390 here we go. Chuck Headey is pronounced hidden without the N. 482 00:26:36.619 --> 00:26:41.170 Who knew? There you go. You've got to read to 483 00:26:41.190 --> 00:26:43.230 the end so you can help you pronounce it. People 484 00:26:43.289 --> 00:26:45.309 help you out there. That is too much work, Neil. 485 00:26:51.200 --> 00:26:55.660 So Brian, we're talking about time travel and wormholes. I presume, 486 00:26:56.680 --> 00:26:59.920 I think everyone knows with Einstein relativity, you can travel 487 00:26:59.960 --> 00:27:02.980 into a future, or at least into the future of 488 00:27:03.019 --> 00:27:05.619 where you once were. So let's confine this to can 489 00:27:05.660 --> 00:27:09.240 you go backwards in time? Do wormholes enable this at all? 490 00:27:09.740 --> 00:27:13.339 Wormholes are getting increasingly interesting, actually, particularly in the study 491 00:27:13.359 --> 00:27:16.700 of black holes. We can get onto that. So yes, 492 00:27:17.019 --> 00:27:21.900 wormholes are allowed geometries in Einstein's theory of general relativity, 493 00:27:22.180 --> 00:27:24.220 if you just take that theory alone. What do I 494 00:27:24.259 --> 00:27:27.180 mean by that? So they really are shortcuts through space 495 00:27:27.240 --> 00:27:29.740 and time. So you can imagine, you know, traveling from 496 00:27:29.809 --> 00:27:32.250 New York to Sydney, it takes a long time. You 497 00:27:32.289 --> 00:27:33.869 go around the surface of the Earth, or you could 498 00:27:33.910 --> 00:27:37.170 tunnel through, and you could get there quicker. So yes, 499 00:27:37.430 --> 00:27:41.960 if wormholes exist, and you could travel through them, and 500 00:27:42.000 --> 00:27:45.589 they were big enough and stable enough, then you can 501 00:27:45.680 --> 00:27:51.670 build a time machine. Now, virtually every physicist who works 502 00:27:51.750 --> 00:27:54.009 on this, and Kip Thorne, actually, who got the Nobel 503 00:27:54.029 --> 00:27:56.950 Prize for gravitational waves, did quite a lot of interesting 504 00:27:56.970 --> 00:27:59.759 work on this. And he was. 505 00:27:59.720 --> 00:28:01.539 The main advisor in the movie Interstellar. 506 00:28:01.619 --> 00:28:02.240 He was, yeah. 507 00:28:02.299 --> 00:28:04.819 In fact, an executive producer. And the robot in that 508 00:28:04.839 --> 00:28:05.579 movie was named Kip. 509 00:28:06.079 --> 00:28:09.319 It was, and it has a wormhole. And he also 510 00:28:09.400 --> 00:28:13.200 actually suggested to Carl Sagan in Contact that wormholes were 511 00:28:13.319 --> 00:28:14.759 used in the film. 512 00:28:14.819 --> 00:28:15.900 In the movie Contact. 513 00:28:15.920 --> 00:28:20.319 And the novel, actually, first. So when you add quantum 514 00:28:20.339 --> 00:28:23.289 mechanics into the mix, which is the theory of everything else, 515 00:28:23.640 --> 00:28:26.049 because our universe hasn't just got gravity in it, it's 516 00:28:26.069 --> 00:28:27.670 got all sorts of other things in it as well, 517 00:28:27.730 --> 00:28:31.549 obviously atoms and electromagnetic radiation and so on, then it 518 00:28:31.750 --> 00:28:35.170 seems like the wormholes are inherently unstable, the big ones. 519 00:28:35.779 --> 00:28:38.299 And if you try to travel through one, it collapses. 520 00:28:38.940 --> 00:28:40.609 So that's basic. I should say, by the way, that 521 00:28:40.640 --> 00:28:44.309 they're such an integral part of Einstein's theory. There's a 522 00:28:44.309 --> 00:28:47.210 very famous paper in the 1930s by Einstein and Rosen. 523 00:28:47.950 --> 00:28:51.549 And they were called Einstein-Rosen bridges before they were wormholes. 524 00:28:52.069 --> 00:28:56.009 And they're built into the basic description of a black hole. 525 00:28:56.170 --> 00:28:59.839 If the black hole had lived forever, it's called the 526 00:28:59.890 --> 00:29:02.279 maximally extended Schwarzschild metric, right? 527 00:29:02.319 --> 00:29:02.500 Whatever. 528 00:29:02.910 --> 00:29:07.089 It's called, but that which was discovered by Schwarzschild in 1916, 529 00:29:07.089 --> 00:29:09.710 just after the theory was published, then there's a wormhole 530 00:29:09.750 --> 00:29:12.269 in there, right?

So they're just fundamental to the theory, 531 00:29:12.730 --> 00:29:16.009 but most physicists believe, and Stephen Hawking wrote a paper 532 00:29:16.049 --> 00:29:19.990 actually called the chronology protection conjecture, conjecture, where he thought 533 00:29:20.039 --> 00:29:20.339 about this. 534 00:29:20.359 --> 00:29:21.539 Who knew he was a rapper? 535 00:29:21.559 --> 00:29:22.359 They will be unstable. 536 00:29:23.160 --> 00:29:23.359 Yeah. 537 00:29:23.700 --> 00:29:25.859 I can even say it. You can say it. I 538 00:29:25.880 --> 00:29:30.579 can't say it. Chronology protection conjecture. Yeah. But these things 539 00:29:30.599 --> 00:29:32.420 would not be stable and you can't travel through them 540 00:29:32.440 --> 00:29:36.230 so you can't build time machines. However, it's worth saying 541 00:29:36.670 --> 00:29:39.910 that wormholes are becoming very, very fashionable now in wormholes. 542 00:29:40.150 --> 00:29:44.819 called the er equals epr paradigm so einstein rosen er 543 00:29:44.880 --> 00:29:47.740 is einstein rosen this thing from the 1930s where einstein 544 00:29:47.759 --> 00:29:50.779 and rosen noticed that they these geometries exist in space 545 00:29:50.819 --> 00:29:55.559 time or can exist epr is einstein podolsky and rosen 546 00:29:55.779 --> 00:29:59.839 spooky action at a distance it's quantum entanglement And so 547 00:30:00.180 --> 00:30:03.680 what now is very fashionable and looks as one of 548 00:30:03.720 --> 00:30:06.019 the best explanations of how information gets out of a 549 00:30:06.059 --> 00:30:09.160 black hole is that this plays a role. So you can, 550 00:30:09.220 --> 00:30:11.380 there's a kind of a dual description. So we've got 551 00:30:11.420 --> 00:30:14.099 quantum entanglement, which is this spooky action at a distance 552 00:30:14.140 --> 00:30:17.079 thing where you separate things to large distances and they're 553 00:30:17.099 --> 00:30:21.119 still linked in some way. The linked in some way 554 00:30:21.319 --> 00:30:24.099 is starting to look possibly like you can describe that 555 00:30:24.140 --> 00:30:28.220 in terms of wormholes. microscopic wormholes linking them together but 556 00:30:28.240 --> 00:30:30.720 this is really this is stuff that's being done now 557 00:30:30.720 --> 00:30:34.339 2020 2022 so it's um it's on the edge but 558 00:30:34.400 --> 00:30:35.160 people are taking it. 559 00:30:35.299 --> 00:30:37.859 Okay so wait let's let's pause there and come back 560 00:30:37.960 --> 00:30:40.880 but all right now you've established that we agree we 561 00:30:40.900 --> 00:30:42.700 can think about wormholes but you haven't told us how 562 00:30:42.740 --> 00:30:45.200 to go backwards in time when we come back brian 563 00:30:45.220 --> 00:30:46.420 cox is going to tell you how to go back 564 00:30:46.819 --> 00:30:49.180 and not kill your parents okay. 565 00:30:50.369 --> 00:30:52.150 And i can tell you an even simpler way if 566 00:30:52.190 --> 00:30:54.630 you really want to go backwards in time get married 567 00:30:54.670 --> 00:30:58.130 and do something wrong Because she will never let you forget. 568 00:30:58.170 --> 00:31:02.420 Forget. Thank you, Chuck, for your marital, splitting your marital 569 00:31:02.480 --> 00:31:06.400 issues into this podcast. StarTalk will return with Brian Cox. 570 00:31:06.420 --> 00:31:08.099 We're going to find out how to go back in time. 571 00:31:08.960 --> 00:31:15.099 Be there. We're back. StarTalk, Cosmic Queries. Got Chuck, of course. Chuck, 572 00:31:15.119 --> 00:31:18.380 you're tweeting at ChuckNiceComic. Thank you, sir. You've got some 573 00:31:18.460 --> 00:31:21.539 fun stuff there that tracks current events and things. It's 574 00:31:21.559 --> 00:31:23.720 always good to see what you have to say about that. 575 00:31:24.200 --> 00:31:27.660 And Brian Cox, my friend and colleague from the UK, 576 00:31:27.769 --> 00:31:30.630 is taking the United States by storm and a little 577 00:31:30.650 --> 00:31:35.750 bit of Canada in dozens of cities. He's bringing his 578 00:31:36.210 --> 00:31:41.069 major theatrical production. Do you give it a title or 579 00:31:41.089 --> 00:31:43.130 is it just everything you want to know about where 580 00:31:43.170 --> 00:31:44.730 we are in the universe? How about that? 581 00:31:45.470 --> 00:31:46.069 Horizons. 582 00:31:46.230 --> 00:31:47.410 Horizons. There it is. 583 00:31:49.259 --> 00:31:52.559 Billy Connell is over that way. No, which way? That way. 584 00:31:52.720 --> 00:31:55.839 There he is. And Brian Cox, you can find his 585 00:31:55.859 --> 00:32:02.750 schedule in briancoxlive.co.uk. Just do a Google on Brian Cox Live. 586 00:32:02.789 --> 00:32:05.230 It'll send you there. And you can see the whole schedule. 587 00:32:05.690 --> 00:32:10.769 And he's coming through town with a hugely visually spectacular display. Cool. 588 00:32:11.150 --> 00:32:14.150 And this is what, you know, this is what stages 589 00:32:14.210 --> 00:32:16.490 are for. If the universe is the biggest stage of 590 00:32:16.529 --> 00:32:20.470 them all, he's brought the universe together. onto into theaters. 591 00:32:20.690 --> 00:32:23.190 So Brian, welcome to town for this. So we left 592 00:32:23.369 --> 00:32:28.339 off with describing wormholes and I have to tell the story. Brian, 593 00:32:28.700 --> 00:32:31.900 I have to tell this, okay? So Brian, you just 594 00:32:32.400 --> 00:32:33.839 stay on the side while I tell this to Chuck. 595 00:32:33.859 --> 00:32:36.640 So Chuck, I'm in London and I'm a guest on 596 00:32:36.680 --> 00:32:40.369 Brian's show. We're talking about space travel and space exploration. 597 00:32:40.890 --> 00:32:44.809 And he's got a whole audience there. They're all UK people, okay? 598 00:32:44.910 --> 00:32:46.690 And they're new to me and I'm a little new 599 00:32:46.710 --> 00:32:49.220 to them, but they know Brian. And they know I'm American. 600 00:32:49.559 -->

00:32:52.160 So I talk about the future of space travel. And 601 00:32:52.220 --> 00:32:55.259 I say, maybe, you know, no, chemical rockets are not 602 00:32:55.279 --> 00:32:57.279 going to work. In order to do this, we need 603 00:32:57.299 --> 00:33:00.200 like warp drives or ideally wormholes. And then we can 604 00:33:00.220 --> 00:33:02.890 do this. And Brian kicks in and said, wormholes are 605 00:33:02.930 --> 00:33:06.569 unstable and they'll collapse and you can't do this. He's correct, 606 00:33:07.049 --> 00:33:09.509 but that's not the point. The point was the audience, 607 00:33:09.529 --> 00:33:11.430 do you remember what the audience said? The audience said, 608 00:33:12.619 --> 00:33:18.880 That's why the Americans discover everything. They're so optimistic about everything. 609 00:33:19.099 --> 00:33:21.660 That's why they went to the moon and we're stuck 610 00:33:21.700 --> 00:33:25.720 here in London. And so you lost your audience on 611 00:33:25.849 --> 00:33:29.369 that comment, Brian. And I had them from that one. 612 00:33:29.410 --> 00:33:33.509 Because they liked my American... Some of it's just me, 613 00:33:33.569 --> 00:33:37.309 but then I realized a lot of it's just American enthusiasm. 614 00:33:37.650 --> 00:33:40.089 So Brian, how do you use wormholes to actually travel 615 00:33:40.130 --> 00:33:41.210 backwards in time? Is that possible? 616 00:33:41.730 --> 00:33:46.910 Well, so... Yeah, if they were stable, or you could 617 00:33:46.950 --> 00:33:49.450 stabilize them in some way, then you could use them 618 00:33:49.490 --> 00:33:58.230 as time machines. And that's considered to be unlikely. But 619 00:33:58.750 --> 00:34:01.309 it really is true to say that we, well, it's 620 00:34:01.369 --> 00:34:03.029 very true to say we don't have what's called a 621 00:34:03.049 --> 00:34:07.490 quantum theory of gravity. So we don't really, in any sense, 622 00:34:07.569 --> 00:34:12.489 understand the deep merger of between relativity and quantum mechanics 623 00:34:12.530 --> 00:34:15.690 which you need to understand to answer that question and 624 00:34:15.710 --> 00:34:18.329 many physicists point out that we don't you know it 625 00:34:18.449 --> 00:34:20.989 feels like it's no way to build the universe we've 626 00:34:21.010 --> 00:34:22.670 all seen back to the future we all know the 627 00:34:22.710 --> 00:34:25.030 paradoxes that happen if you if time travel is a 628 00:34:25.050 --> 00:34:28.610 reality so so i think if you pushed most physicists 629 00:34:28.650 --> 00:34:30.789 and said don't be formal about it and don't say 630 00:34:30.809 --> 00:34:32.650 what i just said which is we don't understand quantum 631 00:34:32.670 --> 00:34:36.750 gravity yet um then most physicists would say okay we 632 00:34:36.849 --> 00:34:39.980 think the laws of nature will be such that There 633 00:34:40.059 --> 00:34:45.260 aren't stable, macroscopic, big wormholes. That's what I think most 634 00:34:45.320 --> 00:34:50.110 physicists would say. But actually, you mentioned interstellar. And Kip 635 00:34:50.150 --> 00:34:52.130 Thorne is one of the world experts on this, does 636 00:34:52.230 --> 00:34:55.329 point out that you can get around this. So you 637 00:34:55.429 --> 00:34:59.909 could have a universe which permitted time travel and was 638 00:34:59.980 --> 00:35:03.320 not full of contradictions if there were no free will 639 00:35:03.760 --> 00:35:08.860 at all. So the whole universe itself is completely consistent 640 00:35:08.880 --> 00:35:11.949 with And the time travel is built into the consistency. 641 00:35:12.070 --> 00:35:15.610 And that's actually what you see in Interstellar. So that 642 00:35:15.730 --> 00:35:18.980 happens in the plot of Interstellar. He can't stop it. 643 00:35:19.030 --> 00:35:21.690 I'm not spoilers, you know, but he can't stop himself 644 00:35:21.789 --> 00:35:24.150 leaving his daughter's room in the past. 645 00:35:24.230 --> 00:35:26.929 And by the way, that's also what happened in the 646 00:35:27.070 --> 00:35:30.769 story Slaughterhouse-Five by Kurt Vonnegut, which is a time travel 647 00:35:30.789 --> 00:35:32.909 story on top of being a World War II story. 648 00:35:33.489 --> 00:35:36.929 And I think Kurt Vonnegut got it right. Correct me 649 00:35:36.949 --> 00:35:39.250 if I'm wrong, Brian. He just described your life is 650 00:35:39.289 --> 00:35:42.090 always there. You're always being born. You're always dying. You're 651 00:35:42.110 --> 00:35:45.650 always in school. You're always in love. And you just 652 00:35:45.730 --> 00:35:48.989 rejoin where you were on that timeline and relive that. 653 00:35:49.340 --> 00:35:53.920 There's a Stephen Hawking's birthday party. No, it's Kip Thorne's 654 00:35:53.960 --> 00:35:57.320 birthday party. There's a proceedings. So Neil, when we go 655 00:35:57.340 --> 00:35:59.760 to scientific conferences, you have a proceedings. It's a big thing. 656 00:36:00.099 --> 00:36:03.320 And there's a proceedings. I think it's Kip's. I think 657 00:36:03.360 --> 00:36:07.780 it's his 60th birthday party. And Stephen Hawking gave a talk, 658 00:36:07.900 --> 00:36:10.579 and it's written up in the proceedings of his birthday 659 00:36:10.639 --> 00:36:14.800 party because he's so eminent. And Stephen said that Kip 660 00:36:14.960 --> 00:36:18.820 has become increasingly interested in time travel through wormholes as 661 00:36:18.900 --> 00:36:23.059 he's got older. That's how he started the paper. That's good. 662 00:36:23.079 --> 00:36:23.739 That's good. That's good. 663 00:36:23.760 --> 00:36:24.429 Chuck, this is how. 664 00:36:33.860 --> 00:36:36.840 Third of three segments. Give me a few, see if 665 00:36:36.860 --> 00:36:38.010 you can slip in a few more questions. 666 00:36:38.030 --> 00:36:42.869 All right, here we go. This is Catherine Cellarini-Moore who says, Dr. Tyson, Dr. Cox, 667 00:36:42.969 --> 00:36:47.269 Lord Nice, hoping that you can hear Dr. Cox

elaborate 668 00:36:47.429 --> 00:36:50.789 on he alluded to in his YouTube video regarding time 669 00:36:50.829 --> 00:36:54.860 and space not being the stuff from which everything else 670 00:36:54.920 --> 00:36:59.500 is derived. Rather, that time and space may be derivative 671 00:36:59.780 --> 00:37:02.940 of something much bigger, much deeper. 672 00:37:02.960 --> 00:37:03.360 Or deeper. 673 00:37:04.280 --> 00:37:09.699 This comes from the study of black holes primarily. And 674 00:37:10.679 --> 00:37:13.800 I would say it looks like space and time emerge 675 00:37:13.860 --> 00:37:18.219 from quantum entanglement. So we mentioned entanglement before. I should 676 00:37:18.260 --> 00:37:19.380 say what it is, by the way. Should I say 677 00:37:19.400 --> 00:37:21.059 what it is? Should I give the one minute introduction 678 00:37:21.099 --> 00:37:21.559 to entanglement? 679 00:37:21.599 --> 00:37:22.519 Sure, sure, sure. 680 00:37:22.780 --> 00:37:26.000 So imagine you have a coin and you can toss 681 00:37:26.079 --> 00:37:28.840 it and it can come up heads and tails. If 682 00:37:28.880 --> 00:37:31.460 it was a quantum coin and there's two of them, 683 00:37:32.050 --> 00:37:34.730 they can be in what we call a state. such 684 00:37:34.789 --> 00:37:37.889 that you could separate these coins out across the Milky 685 00:37:37.929 --> 00:37:41.289 Way to the edges of the universe. And you just 686 00:37:41.329 --> 00:37:43.010 look at one of them and you could toss it 687 00:37:43.090 --> 00:37:45.369 and it would be heads and tails. You can look 688 00:37:45.409 --> 00:37:46.630 at it and it's heads. You look at it again, 689 00:37:46.650 --> 00:37:50.530 it's tails. 50% of the time looks completely normal. But actually, 690 00:37:51.090 --> 00:37:53.849 if you got back together after doing lots of experiments 691 00:37:53.949 --> 00:37:56.960 on this thing, you would find that the coins never 692 00:37:57.039 --> 00:37:59.860 came up heads at the same time or tails at 693 00:37:59.880 --> 00:38:03.159 the same time. They're always heads, tails, plus tails, heads. 694 00:38:03.909 --> 00:38:06.789 Head to tails or tail centric. They're always opposite. So 695 00:38:06.809 --> 00:38:10.469 you can build a quantum state like that. That's called entanglement. 696 00:38:10.969 --> 00:38:15.000 So it's an interesting thing. It's like the information, all 697 00:38:15.039 --> 00:38:18.619 the information contained in this system of two coins is 698 00:38:18.719 --> 00:38:22.800 somehow spread between them and they don't behave as individual entities, 699 00:38:22.900 --> 00:38:26.239 even if you separate them to vast distances. So that's entanglement. 700 00:38:26.469 --> 00:38:29.070 Because they're not just coins, they're also waves. And the 701 00:38:29.130 --> 00:38:32.210 waves know about each other outside of the local place 702 00:38:32.610 --> 00:38:35.369 Were the coins getting flipped? No, it's... If that's the truth, 703 00:38:35.409 --> 00:38:37.190 then I've been saying it wrong all these years. 704 00:38:37.429 --> 00:38:41.530 No, no, they... Really, they are... The best way to 705 00:38:41.570 --> 00:38:46.010 consider it is it's a single system. And the information, 706 00:38:46.090 --> 00:38:48.090 the structure of the system is a property of the 707 00:38:48.110 --> 00:38:48.590 whole thing. 708 00:38:48.809 --> 00:38:49.489 Why is that the wave function? 709 00:38:49.510 --> 00:38:50.530 That's the best way to think about it. 710 00:38:50.530 --> 00:38:51.550 That's got to be the wave function. 711 00:38:51.730 --> 00:38:52.650 Oh, it is the wave, yeah. 712 00:38:52.710 --> 00:38:54.030 Oh, that's what I'm trying to say. 713 00:38:54.429 --> 00:38:57.829 The wave function, you'd write it down. It'd be heads, tails, 714 00:38:57.909 --> 00:39:00.829 plus tails, heads. is an example of a wave function. 715 00:39:01.070 --> 00:39:02.889 And for the geeks there, we can have a one 716 00:39:02.949 --> 00:39:05.230 over root two there in front of each one if 717 00:39:05.250 --> 00:39:05.489 we want. 718 00:39:06.190 --> 00:39:07.429 You've gone too far, Brian. 719 00:39:07.550 --> 00:39:10.429 The key point is it's. 720 00:39:10.449 --> 00:39:12.429 You had me at wave, you lost me at one 721 00:39:12.489 --> 00:39:13.610 over root whatever. 722 00:39:13.869 --> 00:39:14.250 Well, 50%. 723 00:39:14.250 --> 00:39:18.730 So you can have lots of different... Anyway, so that's 724 00:39:18.750 --> 00:39:19.769 an entangled system. 725 00:39:20.929 --> 00:39:24.690 Deep in there is that there's a term that's squared 726 00:39:24.789 --> 00:39:26.349 in the wave function. So he's got to put the 727 00:39:26.389 --> 00:39:28.400 square root of two. so that when you square that, 728 00:39:28.550 --> 00:39:29.389 it becomes a half. 729 00:39:29.750 --> 00:39:31.920 Yeah, if I want 50-50. 730 00:39:32.110 --> 00:39:34.539 That was a missing piece of what he was saying there. 731 00:39:34.780 --> 00:39:40.199 It's the amplitude, right? So that's entanglement. It's a fundamentally 732 00:39:40.300 --> 00:39:43.119 quantum mechanical thing, and it's very well understood, and we 733 00:39:43.199 --> 00:39:46.159 use it in technology and quantum cryptography and so on. 734 00:39:46.199 --> 00:39:48.360 So it's a thing. This is how the universe works. 735 00:39:49.179 --> 00:39:52.579 And it does seem as if, as I mentioned before, 736 00:39:52.639 --> 00:39:55.440 the idea that you can also interpret that as having 737 00:39:55.559 --> 00:39:58.070 wormholes connecting these things together. 738 00:39:58.150 --> 00:39:58.449 I love it. 739 00:39:58.730 --> 00:40:03.730 Essentially what you're seeing is that entanglement and space are 740 00:40:03.869 --> 00:40:07.929 intimately related. That's the modern way of looking at this, 741 00:40:07.969 --> 00:40:11.789 the very modern way. And I think it's fair to 742 00:40:11.849 --> 00:40:14.099 say that most physicists would say

that the entanglement is 743 00:40:14.119 --> 00:40:17.940 the fundamental thing. And so we're beginning to think now 744 00:40:18.670 --> 00:40:21.570 that you have a theory of quantum mechanics, quantum field 745 00:40:21.610 --> 00:40:25.980 theories on some surface or something, and then the entanglement 746 00:40:26.179 --> 00:40:29.760 actually produces the space. I mean, it's true to say 747 00:40:29.800 --> 00:40:33.099 that entanglement, I've seen it said, which is a beautiful 748 00:40:33.119 --> 00:40:35.539 thing to say, that entanglement is sort of the glue 749 00:40:35.619 --> 00:40:41.489 that keeps space together. And so entanglement is fundamentally related 750 00:40:41.530 --> 00:40:47.320 to space. And therefore, time. but it's more obscure. 751 00:40:47.360 --> 00:40:51.559 So that's the next sci-fi frontier, because the latest Doctor 752 00:40:51.599 --> 00:40:55.840 Strange is madness through the multiverse or something. So they 753 00:40:55.860 --> 00:40:58.829 got the multiverse in there, and he's opening up portals, 754 00:40:58.889 --> 00:41:03.489 which are basically wormholes, as he jiggles his hand. So 755 00:41:03.550 --> 00:41:05.409 now we've got to somehow get down into the very 756 00:41:05.469 --> 00:41:08.090 fabric of the space and time itself. That would be good. 757 00:41:08.429 --> 00:41:08.949 All right. 758 00:41:09.250 --> 00:41:09.389 Cool. 759 00:41:09.840 --> 00:41:11.239 Chuck, we got just a couple, but see if we 760 00:41:11.260 --> 00:41:14.530 can go into like lightning mode. Okay, if we can. Okay, go. 761 00:41:14.750 --> 00:41:22.829 Well, let's lighten things up here with Lindahl Freese, who says, Dr. Tyson, Dr. Cox, Chuck, 762 00:41:22.889 --> 00:41:25.469 here is, is there a parameter edge of the universe? 763 00:41:25.869 --> 00:41:28.179 And where in relation to that edge is the Earth 764 00:41:28.260 --> 00:41:31.099 or the Milky Way located? Are we closer or farther 765 00:41:31.139 --> 00:41:33.639 to the center of the universe? Also, how do we 766 00:41:33.719 --> 00:41:36.480 know the universe is expanding? And is it just that 767 00:41:36.539 --> 00:41:39.480 our instruments are getting stronger? 768 00:41:39.500 --> 00:41:39.579 Sure. 769 00:41:40.480 --> 00:41:42.019 Okay, so we need that in a soundbite. 770 00:41:43.619 --> 00:41:46.429 I can do it. So no, we're not at the 771 00:41:46.469 --> 00:41:47.889 center of the universe. We're at the center of the 772 00:41:47.929 --> 00:41:50.969 observable universe because that's just a piece that we can see. 773 00:41:51.570 --> 00:41:55.150 But the universe extends way beyond that horizon. And so 774 00:41:55.510 --> 00:41:56.750 it could be infinite in extent. 775 00:41:57.489 --> 00:41:57.889 We don't know. 776 00:41:58.809 --> 00:42:00.360 But it's much bigger, I think, than the piece we 777 00:42:00.380 --> 00:42:02.219 can see. So no, we're not at the center of 778 00:42:02.280 --> 00:42:05.179 the universe. It might be an infinite universe. We know 779 00:42:05.219 --> 00:42:07.780 it's expanding just very simply because we look at light 780 00:42:07.800 --> 00:42:12.190 from distant objects and that light is stretched. And the 781 00:42:12.230 --> 00:42:15.320 explanation is that light is a wave, and it's traveling 782 00:42:15.360 --> 00:42:19.500 through expanding space. And so it gets stretched as it journeys. 783 00:42:19.539 --> 00:42:22.280 And the basic observation, all the way back to Hubble, 784 00:42:22.860 --> 00:42:24.400 is that the further away you see. 785 00:42:24.460 --> 00:42:26.199 Hubble, the person. Edwin Hubble. 786 00:42:26.489 --> 00:42:28.909 All the way back to Edwin Hubble. The further away 787 00:42:28.949 --> 00:42:30.750 the thing is, the more the light is stretched when 788 00:42:30.789 --> 00:42:33.150 it reaches us. And that's what you would expect if 789 00:42:33.190 --> 00:42:36.789 space were expanding. Essentially, at a uniform rate, it's actually 790 00:42:36.829 --> 00:42:38.809 changing a bit. It's expanding a bit faster now. 791 00:42:40.780 --> 00:42:44.460 So if we said, I want to go to my horizon. Chuck, 792 00:42:44.500 --> 00:42:45.320 let's leave tomorrow. 793 00:42:45.530 --> 00:42:45.719 Yes. 794 00:42:46.239 --> 00:42:47.449 What would we see? 795 00:42:48.489 --> 00:42:50.829 You'd see the same universe as far as we know. 796 00:42:51.250 --> 00:42:54.989 So you could go to the horizon and look around 797 00:42:55.130 --> 00:42:58.800 and you'd see a completely uniform universe. with the same 798 00:42:58.860 --> 00:43:01.469 kind of distribution of galaxies. So like if it's C, 799 00:43:01.559 --> 00:43:04.320 it's carrying its horizon with it, basically. So yes, that's 800 00:43:04.380 --> 00:43:06.400 a good example. If you go to the horizon on 801 00:43:06.639 --> 00:43:09.039 your boat and go to the horizon 20 miles away, 802 00:43:09.079 --> 00:43:12.030 whatever it is, and then I probably got that number wrong, 803 00:43:12.050 --> 00:43:13.750 and now all the flat Earth people will go, C, 804 00:43:13.789 --> 00:43:14.289 didn't know. 805 00:43:16.170 --> 00:43:19.329 There is a horizon, whatever it is. It's way closer 806 00:43:19.349 --> 00:43:21.809 than 20 miles unless you're in a crow's nest. Okay, right. 807 00:43:23.030 --> 00:43:24.869 So you go to the horizon, and you just see ocean. 808 00:43:25.090 --> 00:43:26.909 And you go to the next horizon, you just see ocean. 809 00:43:27.170 --> 00:43:29.340 And that's what the universe is like as far as 810 00:43:29.380 --> 00:43:29.880 we can tell. 811 00:43:29.889 --> 00:43:30.219 Yeah. 812 00:43:30.679 --> 00:43:32.519 I mean, that's as simple as going to the top 813 00:43:32.559 --> 00:43:35.119 of a hill. You experience that any time? Like you're 814 00:43:35.159 --> 00:43:37.320 driving up a hill or on a bike, you look 815 00:43:37.360 --> 00:43:38.719 at the top of the hill, and it just looks 816 00:43:38.760 --> 00:43:40.699 like that's the

end. You get at the top of 817 00:43:40.719 --> 00:43:42.079 the hill, and it's just more of the same. 818 00:43:42.099 --> 00:43:43.460 It's just more and more and more. 819 00:43:43.559 --> 00:43:44.539 This time you're looking down. 820 00:43:44.579 --> 00:43:45.000 More of the same. 821 00:43:45.079 --> 00:43:45.780 That's cool. Yeah. 822 00:43:46.079 --> 00:43:49.699 All right. Let's go to Alain Bredeau, who says. 823 00:43:49.719 --> 00:43:51.710 This might be the last question we have time for. Okay, go. 824 00:43:52.190 --> 00:43:58.219 Alain says this. Hey, Neil, Chuck, and Professor Cox, we 825 00:43:58.300 --> 00:44:02.519 have electron microscopes to probe smaller stuff than with regular 826 00:44:02.619 --> 00:44:06.159 light microscopes. Do you think somebody is going to come 827 00:44:06.219 --> 00:44:10.250 up with a quark microscope or something of that nature 828 00:44:10.289 --> 00:44:13.550 that will enable us to see even smaller or get 829 00:44:13.650 --> 00:44:20.820 closer microscopes? to those strings that theorists fantasize about. 830 00:44:20.960 --> 00:44:23.420 It's an old trickle. 831 00:44:23.460 --> 00:44:25.380 Let me just set that up just real quick. So 832 00:44:25.739 --> 00:44:30.500 regular microscopes use visible light and visible light has certain wavelengths. 833 00:44:31.409 --> 00:44:33.690 So if you really think about it, a visible light 834 00:44:33.710 --> 00:44:37.550 telescope can't see anything smaller than the wavelength of light 835 00:44:37.590 --> 00:44:40.670 you're using because the light would just wash over it 836 00:44:40.750 --> 00:44:43.070 and wouldn't be able to bring it into focus. So 837 00:44:43.639 --> 00:44:48.320 electron microscopes use basically, I think, Brian, is it X-rays? 838 00:44:48.739 --> 00:44:52.460 Because electrons and X-rays are the same thing at certain, 839 00:44:52.900 --> 00:44:55.110 you can beam electrons to have an energy level of 840 00:44:55.139 --> 00:44:59.030 that of an X-ray, and X-rays have really small wavelengths. 841 00:44:59.710 --> 00:45:02.510 So now you can see detail way smaller than visible light. 842 00:45:02.530 --> 00:45:06.230 So this questioner knows this about electron microscopes and wants 843 00:45:06.250 --> 00:45:07.190 to take it another step. 844 00:45:07.590 --> 00:45:10.349 And there's a really great fundamental point to make here, 845 00:45:10.389 --> 00:45:14.489 which goes to black hole physics, actually, again. So as 846 00:45:16.070 --> 00:45:19.110 you take the wavelength down, quantum mechanics allows you to 847 00:45:19.170 --> 00:45:22.010 think of light as a wave or as a stream 848 00:45:22.030 --> 00:45:25.239 of particles called photons. And as you shrink the wavelength, 849 00:45:25.280 --> 00:45:27.780 the energy of the photon goes up. So that's just 850 00:45:27.880 --> 00:45:30.539 basic quantum mechanics. So the smaller the wavelength, the higher 851 00:45:30.579 --> 00:45:33.340 the energy. So you get to a point where if 852 00:45:33.360 --> 00:45:36.969 you want to probe smaller and smaller distances, what actually 853 00:45:37.010 --> 00:45:40.190 happens is you make a black hole. Because you put 854 00:45:40.250 --> 00:45:42.650 so much energy into the small piece of space that 855 00:45:42.670 --> 00:45:45.050 a black hole forms. And then as you put more 856 00:45:45.110 --> 00:45:48.719 energy in, the black hole grows. And so you end 857 00:45:48.760 --> 00:45:53.360 up reversing that process. Because as the black hole grows, 858 00:45:53.380 --> 00:45:57.440 then you get less and less resolution again. So there's 859 00:45:57.480 --> 00:46:00.329 a limit to how small you can see. 860 00:46:00.349 --> 00:46:03.409 So I'll step in here because Chuck didn't. You kept 861 00:46:03.469 --> 00:46:06.400 talking after you said, yeah, first you make the black 862 00:46:06.460 --> 00:46:09.420 hole and then you continue. 863 00:46:09.480 --> 00:46:11.360 So you put more and more energy in. 864 00:46:11.380 --> 00:46:13.820 I'm saying this sounds dangerous, Brian. 865 00:46:15.119 --> 00:46:16.699 It's an in principle argument. 866 00:46:16.739 --> 00:46:19.260 Oh, it's a thought experiment. 867 00:46:19.280 --> 00:46:20.929 The point is that you get to a point where 868 00:46:20.949 --> 00:46:23.670 if you try to cram more and more energy into 869 00:46:23.710 --> 00:46:26.389 a smaller and smaller amount of space, which you have 870 00:46:26.429 --> 00:46:28.369 to do to see the small thing, you have to 871 00:46:28.409 --> 00:46:30.289 get more energy in, right? The smaller wavelength. 872 00:46:30.429 --> 00:46:32.969 Because you're using photons that are... Higher and higher energy. 873 00:46:33.070 --> 00:46:35.590 Or anything, yes. Or anything, electrons or whatever it is. 874 00:46:36.130 --> 00:46:38.610 Then you form, there comes a point where you form 875 00:46:38.650 --> 00:46:40.369 a black hole in that region. 876 00:46:40.409 --> 00:46:42.750 And then you can't say anything because your microscope got 877 00:46:42.829 --> 00:46:48.469 sucked into it. Because you dayed. 878 00:46:48.530 --> 00:46:53.099 You'll have less resolution. So it's called, now Leonard Susskind 879 00:46:53.119 --> 00:46:53.820 writes about it. 880 00:46:54.000 --> 00:46:58.079 Ignoring the complication that you'd be dead. Ignoring the complication 881 00:46:58.099 --> 00:47:00.250 that you'd be dead and you'd destroy the Earth. You'd 882 00:47:00.269 --> 00:47:01.789 have less resolution on your microscope. 883 00:47:01.809 --> 00:47:04.849 No, you wouldn't because it'd be a tiny, tiny black hole. 884 00:47:04.889 --> 00:47:08.860 So you wouldn't notice it, except you'd stop seeing. So 885 00:47:08.900 --> 00:47:12.679 you can't probe smaller and smaller distances forever. I think 886 00:47:12.719 --> 00:47:17.039 Susskind calls it the UVIR connection, ultraviolet infrared connection. I 887 00:47:17.079 --> 00:47:20.389 think that's what he calls it. But it's a fundamental 888 00:47:20.530 --> 00:47:23.809 property of the universe. So black holes stop you from 889 00:47:24.010 --> 00:47:26.420 doing that. going to smaller and smaller and smaller and 890 00:47:26.440 --> 00:47:27.199 smaller distances. 891 00:47:27.260 --> 00:47:28.079 Pesky black hole. 892 00:47:28.139 --> 00:47:28.440 Yes. 893 00:47:28.639 --> 00:47:32.059 Yeah. And again, it's fundamental. It's, it's, it's pointing to 894 00:47:32.099 --> 00:47:34.670 fundamental physics. So we go all the way back to 895 00:47:34.710 --> 00:47:36.989 this idea of space and time and the link to 896 00:47:37.030 --> 00:47:37.590 quantum theory. 897 00:47:38.510 --> 00:47:40.570 Dude, we got to wrap it up there. Oh my gosh. 898 00:47:40.809 --> 00:47:41.130 Wow. 899 00:47:41.590 --> 00:47:45.889 Cover the universe here. Whoa, Brian, this has been a delight. Uh, 900 00:47:46.369 --> 00:47:48.750 I know you're active on Twitter. Where else are you active? 901 00:47:48.769 --> 00:47:51.920 Cause you're prof Brian Cox on Twitter. Uh, where else 902 00:47:52.000 --> 00:47:52.219 are you? 903 00:47:52.679 --> 00:47:56.260 Yeah, I'm on Facebook as well. Um, But Twitter is 904 00:47:56.300 --> 00:48:01.079 my usual mode of communication. I don't know why. It's 905 00:48:01.360 --> 00:48:02.139 just a habit. 906 00:48:02.380 --> 00:48:04.679 I suppose. Yeah, it's a habit. It's quick and easy 907 00:48:04.949 --> 00:48:09.030 and sharp. And so, Brian, always great to see you 908 00:48:09.130 --> 00:48:12.289 and hear from you. And we'll connect again. Chuck, love you, man. 909 00:48:12.309 --> 00:48:12.829 Love you, too. 910 00:48:12.869 --> 00:48:13.409 Always a pleasure. 911 00:48:13.449 --> 00:48:17.639 All right. Neil deGrasse Tyson here, your personal astrophysicist. As always, 912 00:48:17.659 --> 00:48:18.710 keep looking out.