1 00:00:01,735 --> 00:00:03,293 Freeman: Our Universe. 2 00:00:03,370 --> 00:00:07,272 It's awe-inspiring and baffling. 3 00:00:07,340 --> 00:00:10,309 From colossal explosions of stars 4 00:00:10,377 --> 00:00:13,869 to the strange movements of tiny particles... 5 00:00:16,416 --> 00:00:17,678 ...each new discovery 6 00:00:17,751 --> 00:00:20,379 seems to reveal another layer of mystery. 7 00:00:20,453 --> 00:00:24,355 Our understanding of the world around us 8 00:00:24,424 --> 00:00:28,588 has taken us from the Stone Age to the Silicon Age. 9 00:00:30,330 --> 00:00:34,664 Now ironclad laws of physics are breaking apart. 10 00:00:34,734 --> 00:00:41,333 What we believe is reality may not be real at all. 11 00:00:41,408 --> 00:00:44,502 The future of humanity depends on our discovering... 12 00:00:46,413 --> 00:00:49,280 ...how the Universe really works. 13 00:00:56,322 --> 00:01:01,191 Space, time, life itself. 14 00:01:03,229 --> 00:01:07,757 The secrets of the cosmos lie Through the Wormhole. 15 00:01:19,746 --> 00:01:21,611 Think of existence 16 00:01:21,681 --> 00:01:26,175 as an enormous web that we're all woven into, 17 00:01:26,252 --> 00:01:28,948 but we can't see the whole thing. 18 00:01:29,022 --> 00:01:32,014 We just see the patch where we are standing. 19 00:01:32,092 --> 00:01:34,390 We can't see the whole of reality. 20 00:01:34,461 --> 00:01:38,591 But what if we could see it all? 21 00:01:38,665 --> 00:01:40,599 What if we could understand 22 00:01:40,667 --> 00:01:44,763 how the whole of creation joins together? 23 00:01:44,838 --> 00:01:51,107 The rewards of finding this equation would be enormous, 24 00:01:51,177 --> 00:01:53,372 a revolution in science 25 00:01:53,446 --> 00:01:56,643 far beyond anything that has come before - 26 00:01:56,716 --> 00:01:58,445 a great leap forward 27 00:01:58,518 --> 00:02:01,316 that will transform life on Earth 28 00:02:01,387 --> 00:02:05,756 and ensure our survival as a species. 29 00:02:05,825 --> 00:02:08,953 But what hope do we mere mortals have 30 00:02:09,028 --> 00:02:13,294 of uncovering the hidden secrets of the Universe, 31 00:02:13,366 --> 00:02:16,267 of knowing the mind of God? 32 00:02:19,839 --> 00:02:22,831 I remember my first day of school, 33 00:02:22,909 --> 00:02:26,572 the day I was supposed to start learning about the world 34 00:02:26,646 --> 00:02:28,978 and how it works. 35 00:02:29,048 --> 00:02:32,381 I made it about 20 yards to the schoolhouse, 36 00:02:32,452 --> 00:02:34,249 then I froze. 37 00:02:35,922 --> 00:02:37,913 What hope did I have 38 00:02:37,991 --> 00:02:41,586 of understanding everything or anything? 39 00:02:41,661 --> 00:02:45,722 My mind reeled. 40 00:02:45,798 --> 00:02:48,062 I ran back home. 41 00:02:50,537 --> 00:02:55,236 I wonder if scientists feel much the same way. 42 00:02:55,308 --> 00:02:57,606 There is so much we don't know 43 00:02:57,677 --> 00:03:01,738 about why the Universe functions the way it does. 44 00:03:01,814 --> 00:03:04,476 Imagine trying to play a game of chess 45 00:03:04,551 --> 00:03:07,111 if you don't know the rules. 46 00:03:07,187 --> 00:03:09,155 You might figure out some moves, 47 00:03:09,222 --> 00:03:12,157 but a lot of it would make no sense. 48 00:03:12,225 --> 00:03:14,750 Once you know the rules, though, 49 00:03:14,827 --> 00:03:18,729 you can begin to move the pieces with purpose. 50 00:03:18,798 --> 00:03:23,292 Science is our means to discover those rules, 51 00:03:23,369 --> 00:03:26,896 and so far we've revealed quite a few of them. 52 00:03:26,973 --> 00:03:30,500 But what if we've got them wrong? 53 00:03:32,278 --> 00:03:36,544 Deep in the basement tunnels of Purdue University, 54 00:03:36,616 --> 00:03:40,950 scientists Jere Jenkins and Ephraim Fischbach 55 00:03:41,020 --> 00:03:42,487 have discovered 56 00:03:42,555 --> 00:03:46,013 that one of the supposedly unbreakable laws of physics 57 00:03:46,092 --> 00:03:47,389 is broken. 58 00:03:47,460 --> 00:03:50,452 It began with a mystery. 59 00:03:50,530 --> 00:03:52,589 Man: I'll come out and set up a few tethers 60 00:03:52,665 --> 00:03:53,996 and receive some tools, 61 00:03:54,067 --> 00:03:56,797 then he'll come out right after me. 62 00:03:56,869 --> 00:03:58,837 Jenkins: The second week of December of 2006, 63 00:03:58,905 --> 00:04:00,566 astronauts from the space shuttle 64 00:04:00,640 --> 00:04:02,733 were up in the International Space Station, 65 00:04:02,809 --> 00:04:05,209 and everybody was out on an E.V.A., 66 00:04:05,278 --> 00:04:06,677 and there was a solar storm. 67 00:04:16,055 --> 00:04:18,649 Because the astronauts were all out there, 68 00:04:18,725 --> 00:04:20,750 the solar storm was big news. 69 00:04:20,827 --> 00:04:23,057 Sitting there and watching that news story, I thought, 70 00:04:23,129 --> 00:04:24,562 "Wow, wouldn't that be funny 71 00:04:24,631 --> 00:04:28,362 if I saw that appear in the data?" 72 00:04:28,434 --> 00:04:29,264 Freeman: Jenkins studies 73 00:04:29,335 --> 00:04:31,599 a powerful source of energy we can't see 74 00:04:31,671 --> 00:04:33,605 but is all around us - 75 00:04:33,673 --> 00:04:35,231 radioactivity. 76 00:04:35,308 --> 00:04:37,902 Every second of every day, 77 00:04:37,977 --> 00:04:41,572 the Sun sprays out showers of radioactive atoms. 78 00:04:41,648 --> 00:04:44,242 These atoms are unstable. 79 00:04:44,317 --> 00:04:46,683 They spit out energy until they burn away 80 00:04:46,753 --> 00:04:51,349 in a process known as radioactive decay. 81 00:04:51,424 --> 00:04:55,758 Radioactive decay is supposed to be a random process 82 00:04:55,828 --> 00:04:58,695 that cannot be affected by anything. 83 00:04:58,765 --> 00:05:00,995 Jenkins: In early December of 2006, 84 00:05:01,067 --> 00:05:02,762 we're plotting this. 85 00:05:02,835 --> 00:05:04,302 It's a nice, straight line. 86 00:05:04,370 --> 00:05:06,270 It's following exactly like it should, 87 00:05:06,339 --> 00:05:08,466 but then on December 13th, a flare happened. 88 00:05:08,541 --> 00:05:11,476 And we see that the decay has actually departed 89 00:05:11,544 --> 00:05:13,375 what the standard decay line should have been, 90 00:05:13,446 --> 00:05:15,710 and it departed it for quite some time. 91 00:05:15,782 --> 00:05:18,376 This is actually the space of about four days. 92 00:05:18,451 --> 00:05:21,113 It appeared, or so it seemed, 93 00:05:21,187 --> 00:05:23,314 that something may have been changing 94 00:05:23,389 --> 00:05:24,913 this radioactive-decay process, 95 00:05:24,991 --> 00:05:26,959 which nothing is supposed to change. 96 00:05:27,026 --> 00:05:30,518 Freeman: Fischbach, a theoretical physicist, 97 00:05:30,596 --> 00:05:33,793 struggled with the huge implications of this finding. 98 00:05:33,866 --> 00:05:37,097 Knowing how fast radioactive particles break down 99 00:05:37,170 --> 00:05:39,104 is critical for nuclear power, 100 00:05:39,172 --> 00:05:42,767 weapons, electronics, and medicine. 101 00:05:42,842 --> 00:05:46,938 Could it be that a concept so uniformly accepted 102 00:05:47,013 --> 00:05:51,814 and central to modern life was wrong? 103 00:05:51,884 --> 00:05:53,374 The idea that nuclear decays 104 00:05:53,453 --> 00:05:55,921 cannot be influenced by an external influence 105 00:05:55,988 --> 00:05:59,185 is so fundamental to so many aspects of quantum physics, 106 00:05:59,258 --> 00:06:01,283 nuclear physics, elementary-particle physics, 107 00:06:01,361 --> 00:06:03,829 that changing that would likely have a significant change 108 00:06:03,896 --> 00:06:06,194 on our understanding of the Universe, 109 00:06:06,265 --> 00:06:08,563 as well as on practical applications. 110 00:06:08,634 --> 00:06:11,467 Freeman: Still reeling from this shock, 111 00:06:11,537 --> 00:06:14,870 Jenkins and Fischbach uncovered another mystery. 112 00:06:14,941 --> 00:06:17,876 Radioactive decay was not just being affected 113 00:06:17,944 --> 00:06:19,878 by the solar flare. 114 00:06:19,946 --> 00:06:24,110 The discharge of radioactive particles appears to change 115 00:06:24,183 --> 00:06:27,812 depending on how close the Earth is to the Sun. 116 00:06:32,792 --> 00:06:34,384 Fischbach: When the Earth is closer to the Sun, 117 00:06:34,460 --> 00:06:35,893 around January 4th, 118 00:06:35,962 --> 00:06:38,192 the rate of radioactive decay seems to be faster. 119 00:06:38,264 --> 00:06:41,756 And when farther away, the rate seems to be slower. 120 00:06:41,834 --> 00:06:44,234 Now, we can illustrate this in the following way. 121 00:06:44,303 --> 00:06:45,600 I represent the Sun, 122 00:06:45,671 --> 00:06:47,434 and Jere is gonna represent the Earth, 123 00:06:47,507 --> 00:06:48,940 and the bucket represents 124 00:06:49,008 --> 00:06:50,976 a sample of radioactive radium atoms. 125 00:06:53,045 --> 00:06:55,878 And you'll see that as Jere moves in an ellipse, 126 00:06:55,948 --> 00:06:58,815 where he's closer to the Earth around January 4th, 127 00:06:58,885 --> 00:07:00,318 more tennis balls are thrown out, 128 00:07:00,386 --> 00:07:03,651 meaning more particles come out than happen around July 4th. 129 00:07:08,227 --> 00:07:10,058 Freeman: This small change in numbers 130 00:07:10,129 --> 00:07:13,326 could have big consequences. 131 00:07:13,399 --> 00:07:17,233 Cancer patients receive very tiny doses of radiation 132 00:07:17,303 --> 00:07:19,464 to kill their rebel cells. 133 00:07:19,539 --> 00:07:23,236 If the strength of that radiation changes seasonally, 134 00:07:23,309 --> 00:07:27,541 they might get too little or too much of a dose. 135 00:07:27,613 --> 00:07:31,481 Knowing the difference could save lives. 136 00:07:31,551 --> 00:07:34,816 But the duo's most important discovery 137 00:07:34,887 --> 00:07:37,981 could secure the future of the human race. 138 00:07:38,057 --> 00:07:42,255 40 hours prior to the actual time of the flare, 139 00:07:42,328 --> 00:07:45,559 we saw the decay rate change and actually leave the line. 140 00:07:45,631 --> 00:07:48,156 After the flare, 141 00:07:48,234 --> 00:07:51,533 it started to recover and move back toward the line. 142 00:07:51,604 --> 00:07:54,198 So, this possibly gives us the opportunity, then, 143 00:07:54,273 --> 00:07:56,935 to predict when these solar flares are happening. 144 00:07:57,009 --> 00:08:00,604 Freeman: A large solar flare could wipe out 145 00:08:00,680 --> 00:08:04,980 every one of the nearly 3,000 satellites orbiting the Earth. 146 00:08:05,051 --> 00:08:08,111 In a flash, we would lose the Internet, 147 00:08:08,187 --> 00:08:11,850 GPS, television, radio, telephones, 148 00:08:11,924 --> 00:08:16,293 and the systems that control our power grids. 149 00:08:16,362 --> 00:08:22,028 Knowing a flare is coming could avert a global apocalypse. 150 00:08:22,101 --> 00:08:25,229 If this phenomenon is real, as we believe it is, 151 00:08:25,304 --> 00:08:27,738 then it's essential to understand how this is happening 152 00:08:27,807 --> 00:08:29,240 because this will certainly be 153 00:08:29,308 --> 00:08:31,742 a part of a bigger puzzle that we must understand 154 00:08:31,811 --> 00:08:33,574 to put all this physics together. 155 00:08:35,915 --> 00:08:39,146 Freeman: We're groping in the dark of the vast Universe, 156 00:08:39,218 --> 00:08:42,710 thinking we have uncovered its deepest truths, 157 00:08:42,788 --> 00:08:45,689 then finding we still have much to learn 158 00:08:45,758 --> 00:08:48,090 about the rules of nature. 159 00:08:49,328 --> 00:08:53,355 And nature does not make things easy for us. 160 00:08:53,432 --> 00:08:56,333 Down at the smallest scale of existence, 161 00:08:56,402 --> 00:08:59,530 deep in the weird world of quantum mechanics, 162 00:08:59,605 --> 00:09:02,665 it seems to play by two different rules 163 00:09:02,742 --> 00:09:03,868 at the same time. 164 00:09:06,512 --> 00:09:08,946 And the deeper we probe into its mysteries, 165 00:09:09,015 --> 00:09:14,920 the more we are forced to ask not just how the Universe works, 166 00:09:14,987 --> 00:09:18,514 but whether anything is real. 167 00:09:22,995 --> 00:09:26,487 Quantum mechanics has transformed the world. 168 00:09:26,566 --> 00:09:29,433 We owe most of our amazing technology 169 00:09:29,502 --> 00:09:34,462 to its explanations of how extremely small particles... 170 00:09:34,540 --> 00:09:36,599 behave. 171 00:09:36,676 --> 00:09:39,440 But we don't really understand it. 172 00:09:39,512 --> 00:09:43,505 In the quantum world, nothing seems to make sense. 173 00:09:43,583 --> 00:09:47,815 Reality stops being... real. 174 00:09:47,887 --> 00:09:51,050 This mystery is our greatest obstacle 175 00:09:51,123 --> 00:09:53,614 to unlocking the secrets of the Universe. 176 00:09:53,693 --> 00:09:56,161 If we can solve it, 177 00:09:56,228 --> 00:09:59,254 we may hold the keys to creation itself. 178 00:10:07,974 --> 00:10:09,737 Vienna, Austria, 179 00:10:09,809 --> 00:10:13,142 is arguably the birthplace of quantum mechanics. 180 00:10:13,212 --> 00:10:15,043 This is where you will find 181 00:10:15,114 --> 00:10:18,140 the leading quantum experimentalist in the world, 182 00:10:18,217 --> 00:10:21,152 professor Anton Zeilinger. 183 00:10:23,356 --> 00:10:26,154 Zeilinger: When I first heard of quantum mechanics 184 00:10:26,225 --> 00:10:27,522 when I was a student, 185 00:10:27,593 --> 00:10:33,657 I was immediately struck by three things - 186 00:10:33,733 --> 00:10:37,567 first, its unbelievable mathematical beauty. 187 00:10:37,637 --> 00:10:42,074 Secondly, by the incredible precision 188 00:10:42,141 --> 00:10:44,041 to which the predictions work. 189 00:10:44,110 --> 00:10:45,907 And thirdly, 190 00:10:45,978 --> 00:10:51,211 by the fact that... it doesn't make sense. 191 00:10:53,486 --> 00:10:55,886 Freeman: Quantum mechanics describes the behavior 192 00:10:55,955 --> 00:11:00,119 of all the tiny particles that everything is made of. 193 00:11:00,192 --> 00:11:02,422 This knowledge has given us computers, 194 00:11:02,495 --> 00:11:07,262 nuclear power, satellites, advanced medicine - 195 00:11:07,333 --> 00:11:08,595 most of the great leaps forward 196 00:11:08,668 --> 00:11:12,001 humanity has taken in the past 100 years. 197 00:11:12,071 --> 00:11:14,835 But the quantum world seems to run contrary 198 00:11:14,907 --> 00:11:18,570 to everything we know about the laws of nature. 199 00:11:18,644 --> 00:11:23,081 Simply put, down where things are very, very small, 200 00:11:23,149 --> 00:11:26,676 the Universe follows a different set of rules. 201 00:11:29,155 --> 00:11:32,056 Consider the phenomenon of quantum nonlocality, 202 00:11:32,124 --> 00:11:36,151 when two tiny particles instantly share information 203 00:11:36,228 --> 00:11:39,220 across vast distances. 204 00:11:39,298 --> 00:11:42,893 If there were quantum dice, 205 00:11:42,968 --> 00:11:46,563 it would mean that if I throw one die here, 206 00:11:46,639 --> 00:11:49,039 it shows a certain number. 207 00:11:49,108 --> 00:11:52,134 The other dice thrown at some distant location 208 00:11:52,211 --> 00:11:55,442 would show the same number. 209 00:11:55,514 --> 00:11:56,538 How can that be? 210 00:11:56,615 --> 00:11:59,049 Quantum mechanics describes it very well. 211 00:12:00,319 --> 00:12:03,254 Freeman: Time and again Zeilinger has proven 212 00:12:03,322 --> 00:12:06,587 that no matter how extreme its predictions, 213 00:12:06,659 --> 00:12:10,755 quantum theory works even though it shouldn't. 214 00:12:10,830 --> 00:12:13,663 And perhaps the ultimate proof 215 00:12:13,733 --> 00:12:16,497 of just how unsettling quantum mechanics can be 216 00:12:16,569 --> 00:12:20,562 is something called the double-slit experiment. 217 00:12:20,639 --> 00:12:26,407 It will make you question whether reality exists at all. 218 00:12:26,479 --> 00:12:29,312 This simple configuration 219 00:12:29,381 --> 00:12:31,941 shoots particles of light called photons 220 00:12:32,017 --> 00:12:37,182 one at a time through two tiny slits in a screen. 221 00:12:37,256 --> 00:12:40,089 Zeilinger: There's a laser which produces light. 222 00:12:40,159 --> 00:12:41,683 This light is attenuated 223 00:12:41,761 --> 00:12:46,562 such that only one photon at a time emerges. 224 00:12:46,632 --> 00:12:50,796 These photons pass through a two-slit assembly, 225 00:12:50,870 --> 00:12:54,033 and then we have a camera which registers the pattern 226 00:12:54,106 --> 00:12:57,166 behind the two-slit assembly. 227 00:12:57,243 --> 00:13:00,269 So, what we see is that the photons arrive 228 00:13:00,346 --> 00:13:04,214 one by one on the screen - some here, some there - 229 00:13:04,283 --> 00:13:08,379 and it looks pretty random. 230 00:13:08,454 --> 00:13:10,752 Freeman: Since the photons travel one by one - 231 00:13:10,823 --> 00:13:13,951 some through this slit, some through that slit - 232 00:13:14,026 --> 00:13:16,051 you would expect them to leave 233 00:13:16,128 --> 00:13:18,392 a pattern of two stripes on the wall, 234 00:13:18,464 --> 00:13:21,194 and you would be wrong. 235 00:13:21,267 --> 00:13:25,135 They mysteriously create a band of stripes. 236 00:13:25,204 --> 00:13:27,365 This is what you would expect to see 237 00:13:27,439 --> 00:13:31,773 if a constant beam of light shined through the two slits. 238 00:13:31,844 --> 00:13:35,405 It would spread across the wall like a wave. 239 00:13:35,481 --> 00:13:38,814 So, how can single bullet-like particles of light 240 00:13:38,884 --> 00:13:40,579 create a wave pattern? 241 00:13:40,653 --> 00:13:42,348 This could only happen 242 00:13:42,421 --> 00:13:46,619 if the particles go through both slits at the same time. 243 00:13:46,692 --> 00:13:47,886 In other words, 244 00:13:47,960 --> 00:13:51,191 the particle is in two places at once. 245 00:13:51,263 --> 00:13:54,096 But strangest of all is what happens 246 00:13:54,166 --> 00:13:57,932 when you put detectors next to the slits. 247 00:13:58,003 --> 00:14:00,631 When the photons are being watched, 248 00:14:00,706 --> 00:14:04,301 the wave pattern disappears. 249 00:14:04,376 --> 00:14:08,506 Take away the detectors, and the wave pattern comes back. 250 00:14:08,581 --> 00:14:14,986 This suggests that we can change the way reality behaves 251 00:14:15,054 --> 00:14:17,454 just by looking at it. 252 00:14:17,523 --> 00:14:20,788 Does this mean that reality itself 253 00:14:20,860 --> 00:14:23,886 is not real? 254 00:14:23,963 --> 00:14:27,763 The modern answer is that the path taken by the photon 255 00:14:27,833 --> 00:14:30,233 is not an element of reality. 256 00:14:30,302 --> 00:14:34,966 We are not allowed to talk about 257 00:14:35,040 --> 00:14:37,907 the photon passing through this or this slit. 258 00:14:37,977 --> 00:14:39,945 Neither are we allowed to say 259 00:14:40,012 --> 00:14:42,344 that the photons pass through both slits. 260 00:14:42,414 --> 00:14:47,784 All this kind of language is not applicable. 261 00:14:47,853 --> 00:14:52,153 Freeman: So, do we just keep reaping the benefits 262 00:14:52,224 --> 00:14:53,748 from quantum mechanics 263 00:14:53,826 --> 00:14:57,421 and accept that, deep down, nature plays by a set of rules 264 00:14:57,496 --> 00:15:00,226 that will forever remain a mystery? 265 00:15:00,299 --> 00:15:03,029 Zeilinger: The interesting message here is 266 00:15:03,102 --> 00:15:07,163 that we have quantum physics now around for nearly 100 years, 267 00:15:07,239 --> 00:15:09,901 and we are still working at the foundations. 268 00:15:09,975 --> 00:15:12,967 And that tells me that when we find it, 269 00:15:13,045 --> 00:15:16,105 it will be an absolute revelation. 270 00:15:16,181 --> 00:15:19,912 It will be something different from what we have been thinking. 271 00:15:24,390 --> 00:15:27,917 If the quantum theorists are correct, 272 00:15:27,993 --> 00:15:29,756 we will never understand 273 00:15:29,828 --> 00:15:32,456 the fundamental level of the Universe. 274 00:15:32,531 --> 00:15:36,092 Our hopes of finding an ultimate theory will fail, 275 00:15:36,168 --> 00:15:37,499 and the human race 276 00:15:37,569 --> 00:15:41,630 will hit a roadblock it can't break through. 277 00:15:41,707 --> 00:15:44,574 But what if they're wrong? 278 00:15:44,643 --> 00:15:47,111 What if the truth about what happens 279 00:15:47,179 --> 00:15:49,807 deep inside you, me, 280 00:15:49,882 --> 00:15:52,112 and everything else in the Universe 281 00:15:52,184 --> 00:15:55,950 is there if we're willing to look for it? 282 00:15:59,625 --> 00:16:01,786 For most of the 20th century, 283 00:16:01,860 --> 00:16:05,796 scientists believed quantum physics could not be explained, 284 00:16:05,864 --> 00:16:07,889 that we would just have to accept 285 00:16:07,967 --> 00:16:10,868 that we'll never know why things behave as they do 286 00:16:10,936 --> 00:16:14,064 down at the deepest levels of existence. 287 00:16:14,139 --> 00:16:18,007 But now a growing band of rebel scientists thinks 288 00:16:18,077 --> 00:16:20,910 there may be a logical explanation 289 00:16:20,980 --> 00:16:23,471 for quantum weirdness after all 290 00:16:23,549 --> 00:16:25,949 and new hope for revealing 291 00:16:26,018 --> 00:16:30,455 the ultimate truth of our Universe. 292 00:16:30,522 --> 00:16:34,720 The trail begins here... 293 00:16:34,793 --> 00:16:38,229 with a drop of silicon. 294 00:16:38,297 --> 00:16:39,764 In his Paris laboratory, 295 00:16:39,832 --> 00:16:43,268 physicist Yves Couder and his team 296 00:16:43,335 --> 00:16:46,429 conduct an amazing series of experiments. 297 00:16:46,505 --> 00:16:50,134 They are observing the behavior of silicon droplets 298 00:16:50,209 --> 00:16:55,010 bouncing in lockstep on a vibrating plate. 299 00:16:55,080 --> 00:16:56,707 Couder: The liquid of the drop 300 00:16:56,782 --> 00:16:59,114 never touches the liquid of the substrate. 301 00:16:59,184 --> 00:17:01,277 So, they're always separated by a film. 302 00:17:01,353 --> 00:17:02,684 And, in fact, it is stable. 303 00:17:02,755 --> 00:17:05,690 You can keep the drop bouncing on the liquid surface 304 00:17:05,758 --> 00:17:07,692 for several days if you wish. 305 00:17:11,330 --> 00:17:15,664 Freeman: Using a camera that shoots 1,000 frames per second, 306 00:17:15,734 --> 00:17:18,532 Couder has discovered that these droplets 307 00:17:18,604 --> 00:17:22,438 mimic behavior seen in the quantum world. 308 00:17:22,508 --> 00:17:25,705 And that shouldn't be possible, 309 00:17:25,778 --> 00:17:29,214 because the quantum world and the large-scale world 310 00:17:29,281 --> 00:17:31,579 play by two different sets of rules. 311 00:17:39,491 --> 00:17:42,483 Yet here we see a single droplet moving randomly 312 00:17:42,561 --> 00:17:44,495 like a quantum particle, 313 00:17:44,563 --> 00:17:48,397 but behaving like a quantum wave. 314 00:17:48,467 --> 00:17:51,095 If you watch this carefully, you'll notice that the wave 315 00:17:51,170 --> 00:17:53,638 appears to be guiding the droplet. 316 00:17:58,043 --> 00:18:00,443 In fact, the wave fields around the droplets 317 00:18:00,512 --> 00:18:03,743 develop a memory of the trails they have followed. 318 00:18:03,816 --> 00:18:05,750 Despite their random behavior, 319 00:18:05,818 --> 00:18:08,252 they follow a small number of paths. 320 00:18:08,320 --> 00:18:11,721 Again, this is eerily similar 321 00:18:11,790 --> 00:18:14,816 to the behavior of quantum objects. 322 00:18:14,893 --> 00:18:18,021 This runs so contrary to popular belief 323 00:18:18,097 --> 00:18:22,966 that, at first, Couder refused to believe what he was seeing. 324 00:18:23,035 --> 00:18:25,162 Couder: In any physics experiment, 325 00:18:25,237 --> 00:18:28,832 you only see what you are prepared to see. 326 00:18:28,907 --> 00:18:31,068 Of course, it was very obvious that there was a memory, 327 00:18:31,143 --> 00:18:32,974 but it took us some time to realize 328 00:18:33,045 --> 00:18:35,070 that it was that that we were observing, 329 00:18:35,147 --> 00:18:39,140 because you have to adapt to this new idea. 330 00:18:39,218 --> 00:18:41,186 Freeman: Perhaps most revealing of all, 331 00:18:41,253 --> 00:18:45,815 Couder has reproduced the double-slit experiment 332 00:18:45,891 --> 00:18:49,224 using his bouncing silicon droplets. 333 00:18:49,294 --> 00:18:52,092 The mystery of quantum mechanics is, 334 00:18:52,164 --> 00:18:54,155 how can things like electrons 335 00:18:54,233 --> 00:18:59,967 sometimes behave like particles and sometimes behave like waves? 336 00:19:00,038 --> 00:19:03,269 Perhaps this is the answer. 337 00:19:03,342 --> 00:19:07,438 They are particles and waves. 338 00:19:07,513 --> 00:19:12,815 Of course, this system, though small, is not quantum. 339 00:19:12,885 --> 00:19:15,445 Couder: Our system is not a model of quantum mechanics, 340 00:19:15,521 --> 00:19:18,684 but is an association of a particle and a wave. 341 00:19:18,757 --> 00:19:22,090 And some of its properties are similar 342 00:19:22,161 --> 00:19:24,288 to the properties that are observed in quantum mechanics. 343 00:19:24,363 --> 00:19:28,231 Freeman: Couder won't claim that his experiments show us 344 00:19:28,300 --> 00:19:30,063 what is really happening 345 00:19:30,135 --> 00:19:33,468 down at the deepest layers of existence. 346 00:19:33,539 --> 00:19:35,507 But this man will. 347 00:19:35,574 --> 00:19:38,941 To him, those droplets are more proof 348 00:19:39,011 --> 00:19:41,571 that the quantum world makes sense after all 349 00:19:41,647 --> 00:19:45,583 and that reality really exists. 350 00:19:48,487 --> 00:19:52,651 Antony Valentini of Clemson University 351 00:19:52,724 --> 00:19:54,919 is a quantum heretic. 352 00:19:54,993 --> 00:19:56,722 He loudly proclaims 353 00:19:56,795 --> 00:20:00,094 that physics went off the rails in the 1920s 354 00:20:00,165 --> 00:20:03,328 when it embraced the doctrine of quantum uncertainty, 355 00:20:03,402 --> 00:20:06,838 which says that nothing is real until we look at it. 356 00:20:06,905 --> 00:20:10,602 Valentini champions the theory that got left behind. 357 00:20:10,676 --> 00:20:13,110 It was created by one of the pillars 358 00:20:13,178 --> 00:20:15,612 of early 20th-century physics, 359 00:20:15,681 --> 00:20:17,979 Louis De Broglie. 360 00:20:18,050 --> 00:20:19,711 Valentini: Louis De Broglie's original idea is 361 00:20:19,785 --> 00:20:25,314 an electron is both a wave and a particle all the time. 362 00:20:25,390 --> 00:20:28,325 It's not the case that, well, sometimes it's a particle, 363 00:20:28,393 --> 00:20:29,860 sometimes it's a wave. 364 00:20:29,928 --> 00:20:34,558 There is a wave guiding a particle at all times. 365 00:20:34,633 --> 00:20:37,727 And De Broglie called this a pilot wave. 366 00:20:37,803 --> 00:20:40,067 Freeman: In quantum theory, 367 00:20:40,138 --> 00:20:44,165 there's something called the probability wave, 368 00:20:44,243 --> 00:20:47,940 a purely mathematical object that tells you the chance 369 00:20:48,013 --> 00:20:51,244 of finding an electron at any point in space. 370 00:20:51,316 --> 00:20:52,647 Pilot wave theory 371 00:20:52,718 --> 00:20:57,087 treats this wave as a real physical object. 372 00:21:01,860 --> 00:21:05,057 Valentini: So, a simple analog is a bottle. 373 00:21:05,130 --> 00:21:08,293 Someone is on an island, and they want to send a message. 374 00:21:08,367 --> 00:21:10,801 So they write something on a piece of paper, 375 00:21:10,869 --> 00:21:14,600 put it in a bottle, close it, and throw it in the ocean. 376 00:21:17,509 --> 00:21:23,675 And water waves simply push the bottle along. 377 00:21:23,749 --> 00:21:26,149 Freeman: There is a crucial difference 378 00:21:26,218 --> 00:21:30,211 between the waves we know and the pilot wave. 379 00:21:30,289 --> 00:21:32,416 According to the theory, 380 00:21:32,491 --> 00:21:35,892 pilot waves exist in hidden dimensions of space 381 00:21:35,961 --> 00:21:39,089 beyond the three we know. 382 00:21:39,164 --> 00:21:42,065 If true, this means that, 383 00:21:42,134 --> 00:21:45,160 contrary to the accepted theory in physics, 384 00:21:45,237 --> 00:21:49,139 quantum objects obey the same rules as large objects. 385 00:21:49,207 --> 00:21:52,142 They do not exist in two places at once. 386 00:21:52,210 --> 00:21:55,077 They're part of the real world. 387 00:21:55,147 --> 00:21:58,173 Valentini: I think that quantum mechanics itself 388 00:21:58,250 --> 00:22:00,081 is not even a candidate 389 00:22:00,152 --> 00:22:03,553 for the truth about the microscopic world, 390 00:22:03,622 --> 00:22:06,250 because it simply doesn't attempt to describe 391 00:22:06,325 --> 00:22:08,452 precisely what the microscopic world is. 392 00:22:08,527 --> 00:22:11,758 The mere fact that there are different theories 393 00:22:11,830 --> 00:22:13,957 about what the answer might be 394 00:22:14,032 --> 00:22:16,865 doesn't mean that there's no answer. 395 00:22:16,935 --> 00:22:19,597 And eventually one of them is found to be the correct one. 396 00:22:19,671 --> 00:22:23,505 Freeman: To understand how the Universe works, 397 00:22:23,575 --> 00:22:25,736 we need to unlock 398 00:22:25,811 --> 00:22:28,609 why the quantum world is so different 399 00:22:28,680 --> 00:22:31,478 from the world we know. 400 00:22:31,550 --> 00:22:33,450 It is an unsolved mystery 401 00:22:33,518 --> 00:22:36,453 that affects every single person on Earth, 402 00:22:36,521 --> 00:22:40,787 and this man thinks he can solve it. 403 00:22:45,764 --> 00:22:49,359 The more we understand the inner workings of the Universe, 404 00:22:49,434 --> 00:22:52,699 the more we humans are rewarded with new medicines, 405 00:22:52,771 --> 00:22:53,931 new technologies, 406 00:22:54,005 --> 00:22:57,497 and undreamed of improvements in our lives. 407 00:22:57,576 --> 00:23:00,010 But some say we're a long way off 408 00:23:00,078 --> 00:23:03,309 from unlocking the Universe's deepest secrets. 409 00:23:03,382 --> 00:23:06,180 We want definitive answers. 410 00:23:06,251 --> 00:23:11,314 What we have are mysteries upon mysteries. 411 00:23:13,258 --> 00:23:15,852 And one of the greatest mysteries 412 00:23:15,927 --> 00:23:17,656 is how the big stuff 413 00:23:17,729 --> 00:23:20,630 and the small stuff in the Universe fit together. 414 00:23:23,435 --> 00:23:28,168 Two well-tested theories describe how matter behaves - 415 00:23:28,240 --> 00:23:29,468 relativity theory, 416 00:23:29,541 --> 00:23:32,135 which governs the physics of the large, 417 00:23:32,210 --> 00:23:36,306 and quantum theory, which describes the very small. 418 00:23:36,381 --> 00:23:40,784 If they were a couple, relativity would be a logical, 419 00:23:40,852 --> 00:23:42,945 pocket-protector-wearing engineer 420 00:23:43,021 --> 00:23:46,787 who strictly follows the speed limit of light. 421 00:23:46,858 --> 00:23:49,520 Quantum theory would be his volatile artist wife 422 00:23:49,594 --> 00:23:51,653 who seems to be everywhere at once. 423 00:23:51,730 --> 00:23:54,290 On paper, they don't get along. 424 00:23:54,366 --> 00:23:58,564 But in the real world, they are a happy pair. 425 00:23:58,637 --> 00:24:00,867 And like some real-life odd couples, 426 00:24:00,939 --> 00:24:03,931 no one understands why. 427 00:24:04,009 --> 00:24:08,241 The mystery boils down to gravity. 428 00:24:08,313 --> 00:24:10,941 Gravity dominates the world we know, 429 00:24:11,016 --> 00:24:13,541 and thanks to Newton and Einstein, 430 00:24:13,618 --> 00:24:16,587 we understand it pretty well. 431 00:24:16,655 --> 00:24:19,988 But physicists have no idea what role gravity plays 432 00:24:20,058 --> 00:24:21,753 in the quantum realm 433 00:24:21,827 --> 00:24:25,024 or its effect on space and time. 434 00:24:25,096 --> 00:24:27,155 If we crack this mystery, 435 00:24:27,232 --> 00:24:30,531 we will finally know if it is possible 436 00:24:30,602 --> 00:24:37,269 to travel back in time or through a wormhole. 437 00:24:37,342 --> 00:24:41,711 Petr Horava has a history of exploring 438 00:24:41,780 --> 00:24:44,908 the wild frontier of physics. 439 00:24:44,983 --> 00:24:49,511 Now he's tackling quantum gravity. 440 00:24:49,588 --> 00:24:52,853 Horava: So, how do you reconcile quantum mechanics and gravity? 441 00:24:52,924 --> 00:24:55,518 There are several different ways it can happen. 442 00:24:55,594 --> 00:24:58,154 Either quantum mechanics is stronger and wins 443 00:24:58,230 --> 00:24:59,925 and gravity has to be modified, 444 00:24:59,998 --> 00:25:02,831 or quantum mechanics has to be modified 445 00:25:02,901 --> 00:25:06,166 and gravity stays the same as in Einstein's general relativity. 446 00:25:08,373 --> 00:25:10,898 Freeman: Petr feels the key is 447 00:25:10,976 --> 00:25:12,876 to watch how things change in scale 448 00:25:12,944 --> 00:25:14,844 between the upper layers of nature, 449 00:25:14,913 --> 00:25:17,108 where gravity holds sway, 450 00:25:17,182 --> 00:25:20,913 and the quantum layers down below. 451 00:25:20,986 --> 00:25:24,615 Nature organizes itself in layers of structure, 452 00:25:24,689 --> 00:25:28,785 and you see more and more layers as you zoom in 453 00:25:28,860 --> 00:25:33,763 and gain a better resolution of how you view the system. 454 00:25:33,832 --> 00:25:35,959 It's one of the most important theoretical concepts 455 00:25:36,034 --> 00:25:37,228 in modern physics. 456 00:25:39,571 --> 00:25:42,233 Freeman: To Petr, nature is an archaeological dig 457 00:25:42,307 --> 00:25:46,175 that we're slowly excavating layer by layer. 458 00:25:46,244 --> 00:25:49,839 Right now, we're only capable of uncovering a small part 459 00:25:49,915 --> 00:25:52,577 of the vast and complex ultimate truth. 460 00:25:52,651 --> 00:25:54,881 But we can learn a lot 461 00:25:54,953 --> 00:25:57,285 by comparing the layers we can see. 462 00:26:02,594 --> 00:26:05,062 In this picture, the two images of Mona Lisa 463 00:26:05,130 --> 00:26:07,428 represent the two faces of space-time - 464 00:26:07,499 --> 00:26:09,262 space and time. 465 00:26:09,334 --> 00:26:10,358 They look the same 466 00:26:10,435 --> 00:26:12,460 when we look at it at large scales, 467 00:26:12,537 --> 00:26:14,937 but perhaps when we zoom in 468 00:26:15,006 --> 00:26:18,305 and look at the system at much smaller scales, 469 00:26:18,376 --> 00:26:20,674 it could be that space and time scale 470 00:26:20,745 --> 00:26:22,508 in a very different way. 471 00:26:22,581 --> 00:26:25,414 This could be the missing piece of the puzzle 472 00:26:25,483 --> 00:26:26,677 of quantum gravity. 473 00:26:26,751 --> 00:26:29,618 Freeman: Petr suspects that as you shrink down 474 00:26:29,688 --> 00:26:32,919 to the smallest and deepest level of existence, 475 00:26:32,991 --> 00:26:36,552 space begins to stretch at a different rate from time 476 00:26:36,628 --> 00:26:40,394 until they tear apart. 477 00:26:40,465 --> 00:26:43,229 Think of space-time as analogous to this sheet of paper. 478 00:26:43,301 --> 00:26:45,292 At microscopic scales, 479 00:26:45,370 --> 00:26:48,066 it's smooth and geometric, two-dimensional. 480 00:26:48,139 --> 00:26:53,270 But if you tear the piece of paper into two halves 481 00:26:53,345 --> 00:26:55,404 and look at the edge of the paper - 482 00:26:55,480 --> 00:26:59,007 zoom in, zoom out - 483 00:26:59,084 --> 00:27:01,075 the structure is similar to itself, 484 00:27:01,152 --> 00:27:02,983 but only if you stretch in the horizontal direction 485 00:27:03,054 --> 00:27:04,248 with a different rate 486 00:27:04,322 --> 00:27:06,984 than when you stretch with a vertical direction. 487 00:27:07,058 --> 00:27:10,255 Freeman: From a distance, the tear looks smooth. 488 00:27:10,328 --> 00:27:12,558 But close up, 489 00:27:12,631 --> 00:27:15,464 you can see mountains and valleys along the edge. 490 00:27:15,533 --> 00:27:18,866 Similarly, space and time seem perfectly joined 491 00:27:18,937 --> 00:27:20,165 from a distance. 492 00:27:20,238 --> 00:27:23,833 But close up, you can see the separation. 493 00:27:23,908 --> 00:27:27,810 Petr thinks this tearing apart of time and space 494 00:27:27,879 --> 00:27:30,746 at the microscopic scale is precisely why 495 00:27:30,815 --> 00:27:35,718 the strange rules of quantum mechanics emerge. 496 00:27:35,787 --> 00:27:39,279 If space and time are unhinged, 497 00:27:39,357 --> 00:27:43,521 particles can't be in a specific place at a specific time. 498 00:27:43,595 --> 00:27:47,929 Hence, fuzziness and uncertainty. 499 00:27:47,999 --> 00:27:50,661 Unraveling the enigma of quantum gravity 500 00:27:50,735 --> 00:27:52,600 is a major hurdle in our quest 501 00:27:52,671 --> 00:27:55,936 to understand how the Universe works. 502 00:27:56,007 --> 00:27:58,635 But it shrinks against the magnitude 503 00:27:58,710 --> 00:28:02,612 of the biggest mystery facing humanity. 504 00:28:02,681 --> 00:28:07,709 95% of the Universe is missing. 505 00:28:07,786 --> 00:28:12,553 This woman may know where and what it is. 506 00:28:17,762 --> 00:28:19,992 The more we peel away the layers of nature, 507 00:28:20,065 --> 00:28:25,401 the more we realize that something is missing - 508 00:28:25,470 --> 00:28:27,461 something big. 509 00:28:27,539 --> 00:28:29,700 An enormous chunk of the Universe 510 00:28:29,774 --> 00:28:31,833 seems to be invisible. 511 00:28:31,910 --> 00:28:36,404 We can't see it, hear it, or detect it in any way. 512 00:28:36,481 --> 00:28:40,417 But if we want to unlock the secrets of the Universe, 513 00:28:40,485 --> 00:28:43,283 if we want to advance as a species, 514 00:28:43,354 --> 00:28:46,790 we have to find out what and where it is. 515 00:28:50,895 --> 00:28:54,422 The Universe began with the Big Bang, 516 00:28:54,499 --> 00:28:58,731 a shattering explosion of raw energy. 517 00:28:58,803 --> 00:29:04,105 That energy burst outward in a mass of superheated plasma. 518 00:29:04,175 --> 00:29:06,905 As it cooled, it began to clump together 519 00:29:06,978 --> 00:29:09,708 into all the material in the Universe - 520 00:29:09,781 --> 00:29:15,276 the solids, liquids, and gases that everything is made of. 521 00:29:15,353 --> 00:29:19,449 To crack the cosmic code that underlies our Universe, 522 00:29:19,524 --> 00:29:24,223 we have to understand energy in all its forms. 523 00:29:24,295 --> 00:29:27,560 But what if almost 95% of the Universe 524 00:29:27,632 --> 00:29:30,829 is made of a form of energy we can't see 525 00:29:30,902 --> 00:29:33,097 and don't understand? 526 00:29:33,171 --> 00:29:35,935 These are the kinds of questions 527 00:29:36,007 --> 00:29:39,067 confronted daily in Geneva, Switzerland, 528 00:29:39,144 --> 00:29:42,170 the home of the world's largest particle accelerator - 529 00:29:42,247 --> 00:29:44,374 the Large Hadron Collider - 530 00:29:44,449 --> 00:29:48,010 and also hundreds of physicists. 531 00:29:52,123 --> 00:29:55,718 Clare Burrage is one of them, but she's hardly typical. 532 00:29:58,163 --> 00:30:01,394 Young, female, and an accomplished figure skater, 533 00:30:01,466 --> 00:30:04,299 Clare is trying to solve the vast mystery 534 00:30:04,369 --> 00:30:06,166 of the missing Universe. 535 00:30:12,277 --> 00:30:14,302 Burrage: So, if we think about the Sun, 536 00:30:14,379 --> 00:30:17,610 the light from the Sun carries energy to us here on Earth, 537 00:30:17,682 --> 00:30:19,946 and we can feel the warmth of the Sun on our skin 538 00:30:20,018 --> 00:30:21,246 on a nice day. 539 00:30:21,319 --> 00:30:24,288 But Einstein tells us that what's happening is 540 00:30:24,355 --> 00:30:26,289 that energy and mass are the same thing. 541 00:30:26,357 --> 00:30:28,052 So, in the center of the Sun, 542 00:30:28,126 --> 00:30:29,787 mass is being turned into energy, 543 00:30:29,861 --> 00:30:32,227 and that's what's transmitted by the light 544 00:30:32,297 --> 00:30:34,663 here to us on Earth. 545 00:30:34,732 --> 00:30:36,063 So, the energy from the Sun 546 00:30:36,134 --> 00:30:38,034 we know and we understand very well, 547 00:30:38,102 --> 00:30:40,070 but it seems like there's another form of energy 548 00:30:40,138 --> 00:30:41,935 out there in the Universe called dark energy 549 00:30:42,006 --> 00:30:43,473 that we don't understand at all. 550 00:30:43,541 --> 00:30:46,942 Freeman: Accepted laws of physics dictate 551 00:30:47,011 --> 00:30:50,412 that the expansion of the Universe after the Big Bang 552 00:30:50,481 --> 00:30:52,540 should be slowing down. 553 00:30:52,617 --> 00:30:56,053 But recent astronomical observations have revealed 554 00:30:56,120 --> 00:31:01,080 that the expansion is rapidly speeding up. 555 00:31:01,159 --> 00:31:07,496 Some unexplained form of energy is pushing galaxies apart. 556 00:31:07,565 --> 00:31:08,862 Burrage: So, at the moment, 557 00:31:08,933 --> 00:31:10,924 I'm moving forward even though I'm not doing anything 558 00:31:11,002 --> 00:31:12,526 because of the force of gravity. 559 00:31:12,604 --> 00:31:13,696 But if I were in space, 560 00:31:13,771 --> 00:31:15,705 where there are no forces acting on me, 561 00:31:15,773 --> 00:31:17,365 I shouldn't be moving at all. 562 00:31:17,442 --> 00:31:18,773 If I'm moving forwards, 563 00:31:18,843 --> 00:31:21,744 then there has to be something very strange acting on me, 564 00:31:21,813 --> 00:31:23,508 and this is what we call dark energy. 565 00:31:23,581 --> 00:31:28,018 Freeman: How much of the Universe is dark energy? 566 00:31:28,086 --> 00:31:29,781 Put it this way. 567 00:31:29,854 --> 00:31:31,788 Here's the Universe. 568 00:31:31,856 --> 00:31:37,954 This sliver, 4.6%, is all the matter we can see. 569 00:31:38,029 --> 00:31:40,657 Near-massless particles called neutrinos 570 00:31:40,732 --> 00:31:44,099 take up another 0.4%. 571 00:31:44,168 --> 00:31:47,797 We think that something called dark matter 572 00:31:47,872 --> 00:31:51,273 accounts for another 23%. 573 00:31:51,342 --> 00:31:56,939 Dark energy is the remaining 72% 574 00:31:57,015 --> 00:32:02,419 of the mass and energy of the Universe. 575 00:32:02,487 --> 00:32:07,550 We cannot see it, touch it, taste it, or detect it, 576 00:32:07,625 --> 00:32:11,891 but cosmologists are certain it is there. 577 00:32:15,767 --> 00:32:18,292 Without dark energy, 578 00:32:18,369 --> 00:32:23,500 gravity would cause the Universe to collapse in on itself. 579 00:32:28,947 --> 00:32:32,474 Clare suspects that dark energy is a by-product 580 00:32:32,550 --> 00:32:34,780 of a radical new piece of physics, 581 00:32:34,852 --> 00:32:38,948 an undiscovered particle called the chameleon. 582 00:32:39,023 --> 00:32:41,787 These mysterious particles 583 00:32:41,859 --> 00:32:44,885 actually carry an entirely different basic force 584 00:32:44,963 --> 00:32:47,591 than the four that physicists know about, 585 00:32:47,665 --> 00:32:50,429 a fifth fundamental force. 586 00:32:53,671 --> 00:32:55,298 Burrage: In physics as we understand it, 587 00:32:55,373 --> 00:32:56,840 there are four forces. 588 00:32:56,908 --> 00:33:00,503 So, they are gravity, which holds us here on Earth. 589 00:33:00,578 --> 00:33:03,945 There are the electric interactions between atoms 590 00:33:04,015 --> 00:33:05,949 and the strong and weak forces 591 00:33:06,017 --> 00:33:08,485 that control what happens in atoms. 592 00:33:08,553 --> 00:33:11,249 And so if there is something new, 593 00:33:11,322 --> 00:33:13,290 a new particle like the chameleon, 594 00:33:13,358 --> 00:33:14,723 like dark energy, 595 00:33:14,792 --> 00:33:18,125 it's going to look to us like there's a fifth force out there. 596 00:33:20,231 --> 00:33:23,758 This force carrier is called a chameleon 597 00:33:23,835 --> 00:33:26,998 because it can change its appearance. 598 00:33:27,071 --> 00:33:28,595 When it is heavy, 599 00:33:28,673 --> 00:33:31,437 it becomes sluggish and ineffective. 600 00:33:31,509 --> 00:33:32,942 When it is light, 601 00:33:33,011 --> 00:33:36,879 it can zip around much faster and become stronger. 602 00:33:36,948 --> 00:33:41,009 How heavy it is depends on its environment - 603 00:33:41,085 --> 00:33:43,986 how much stuff is around it. 604 00:33:44,055 --> 00:33:46,956 Burrage: So, here on Earth, there's a lot of stuff around, 605 00:33:47,025 --> 00:33:48,151 a lot of matter, 606 00:33:48,226 --> 00:33:50,854 and the chameleon becomes very heavy, very massive. 607 00:33:50,928 --> 00:33:53,692 It doesn't interact with the things around it very much, 608 00:33:53,765 --> 00:33:56,325 and that's why we don't see it in our everyday lives 609 00:33:56,401 --> 00:33:58,096 and in experiments here on Earth. 610 00:33:58,169 --> 00:34:01,969 But in intergalactic space, where there's almost nothing, 611 00:34:02,040 --> 00:34:04,338 the chameleon becomes very, very light, 612 00:34:04,409 --> 00:34:07,572 and it can interact with things over huge distances. 613 00:34:07,645 --> 00:34:10,409 And that's why it can drive the acceleration 614 00:34:10,481 --> 00:34:12,346 of the expansion of the Universe. 615 00:34:12,417 --> 00:34:14,612 Freeman: This shape-shifting property 616 00:34:14,685 --> 00:34:17,176 explains why the chameleon has yet to be spotted 617 00:34:17,255 --> 00:34:19,450 in our particle accelerators. 618 00:34:19,524 --> 00:34:21,321 It should be everywhere - 619 00:34:21,392 --> 00:34:26,261 inside you and me and far out in the cosmos. 620 00:34:26,330 --> 00:34:31,700 But how do we detect a master of disguise? 621 00:34:31,769 --> 00:34:35,296 Burrage: The chameleon shows up in experiments 622 00:34:35,373 --> 00:34:37,705 on really tiny scales and on really huge scales. 623 00:34:37,775 --> 00:34:40,175 So you can look for it 624 00:34:40,244 --> 00:34:41,905 in the ways that particles behave in colliders 625 00:34:41,979 --> 00:34:42,911 on really tiny scales. 626 00:34:42,980 --> 00:34:44,140 But also, 627 00:34:44,215 --> 00:34:46,445 it affects the way that light travels, 628 00:34:46,517 --> 00:34:48,815 and so we can look on very large scales 629 00:34:48,886 --> 00:34:50,444 at how light from stars comes to us 630 00:34:50,521 --> 00:34:51,510 and whether we can see 631 00:34:51,589 --> 00:34:53,113 the effects of the chameleon there. 632 00:34:53,191 --> 00:34:57,560 Freeman: Our slow and steady understanding 633 00:34:57,628 --> 00:35:00,597 of electromagnetism and the nuclear forces 634 00:35:00,665 --> 00:35:02,997 has transformed our lives, 635 00:35:03,067 --> 00:35:06,059 from electricity to telecommunications, 636 00:35:06,137 --> 00:35:09,072 transportation to warfare. 637 00:35:09,140 --> 00:35:12,803 What benefits could dark energy bring us? 638 00:35:14,946 --> 00:35:16,277 It's very hard to say now 639 00:35:16,347 --> 00:35:18,542 how a better understanding of dark energy 640 00:35:18,616 --> 00:35:20,584 is going to make people's lives better. 641 00:35:20,651 --> 00:35:23,085 But in the past, understanding things better 642 00:35:23,154 --> 00:35:25,349 has always led to benefits for mankind. 643 00:35:25,423 --> 00:35:28,392 So, in some ways, understanding dark energy, 644 00:35:28,459 --> 00:35:30,654 for understanding the Universe, it's more important 645 00:35:30,728 --> 00:35:32,923 than understanding the physics that we know here on Earth. 646 00:35:32,997 --> 00:35:35,124 The particles that we understand 647 00:35:35,199 --> 00:35:38,760 make up about a percent of the Universe as we know it. 648 00:35:38,836 --> 00:35:43,068 Dark energy is a massively more important contribution. 649 00:35:43,141 --> 00:35:46,508 Freeman: Dark energy is the unknown variable 650 00:35:46,577 --> 00:35:50,172 in our quest to crack the cosmic code... 651 00:35:50,248 --> 00:35:52,546 to find a set of equations 652 00:35:52,617 --> 00:35:56,553 that describe how the Universe really works. 653 00:35:56,621 --> 00:36:00,921 But this man says that doesn't go far enough. 654 00:36:00,992 --> 00:36:05,622 He believes equations don't just describe the Universe. 655 00:36:05,696 --> 00:36:09,097 Equations are the Universe, 656 00:36:09,167 --> 00:36:12,261 and we are all living inside them. 657 00:36:14,472 --> 00:36:17,373 We are hunting for an ultimate equation, 658 00:36:17,441 --> 00:36:19,238 the theory of everything 659 00:36:19,310 --> 00:36:22,871 that will explain the mechanisms of the Universe 660 00:36:22,947 --> 00:36:26,075 and revolutionize life on Earth. 661 00:36:26,150 --> 00:36:29,586 One man believes that equation exists 662 00:36:29,654 --> 00:36:33,886 and the solution is the Universe. 663 00:36:33,958 --> 00:36:35,823 According to him, 664 00:36:35,893 --> 00:36:41,263 the equation of everything is everywhere you look, 665 00:36:41,332 --> 00:36:44,631 and we are all part of it. 666 00:36:48,072 --> 00:36:51,633 Max Tegmark lives in Winchester, Massachusetts, 667 00:36:51,709 --> 00:36:53,973 a northern suburb of Boston. 668 00:36:54,045 --> 00:36:56,570 He's an outdoorsy sort 669 00:36:56,647 --> 00:37:00,139 who likes to go on long walks and think. 670 00:37:00,218 --> 00:37:03,085 But Tegmark's thoughts are a bit more exotic 671 00:37:03,154 --> 00:37:06,021 than your average power walker's ponderings. 672 00:37:06,090 --> 00:37:07,387 Tegmark: I think the reason 673 00:37:07,458 --> 00:37:10,586 our Universe is so well-described by math 674 00:37:10,661 --> 00:37:13,892 is that it is math, in the sense that we are living 675 00:37:13,965 --> 00:37:15,933 in a giant mathematical structure. 676 00:37:16,000 --> 00:37:19,993 So, the reason we physicists have discovered 677 00:37:20,071 --> 00:37:23,905 all of these equations which describe our world so well 678 00:37:23,975 --> 00:37:25,909 is simply because these equations 679 00:37:25,977 --> 00:37:27,308 can approximately describe 680 00:37:27,378 --> 00:37:30,211 the true math which is our reality. 681 00:37:30,281 --> 00:37:32,044 Freeman: To Tegmark, 682 00:37:32,116 --> 00:37:34,983 equations are windows on the Universe, 683 00:37:35,052 --> 00:37:38,351 and the Universe is pure math. 684 00:37:38,422 --> 00:37:40,287 Tegmark: At first glance, 685 00:37:40,358 --> 00:37:43,350 our Universe doesn't seem mathematical at all. 686 00:37:43,427 --> 00:37:46,328 We don't have big numbers written visibly in the sky. 687 00:37:46,397 --> 00:37:48,695 But if we look more closely, 688 00:37:48,766 --> 00:37:54,363 we find mathematical patterns and shapes all around us. 689 00:37:54,438 --> 00:37:58,135 Like, if I mess around with my garden hose here... 690 00:37:58,209 --> 00:38:02,009 the water makes this very simple shape called a parabola, 691 00:38:02,079 --> 00:38:05,674 which has this extremely simple mathematical equation, 692 00:38:05,750 --> 00:38:07,809 "Y" equals "X" squared. 693 00:38:07,885 --> 00:38:10,581 This mathematical shape, the parabola, 694 00:38:10,655 --> 00:38:13,920 is really built into nature at quite a fundamental level 695 00:38:13,991 --> 00:38:16,186 because it describes the motion with gravity 696 00:38:16,260 --> 00:38:19,024 of any object, regardless of what it's made of. 697 00:38:26,904 --> 00:38:29,532 When we look around us in the Universe, 698 00:38:29,607 --> 00:38:31,302 we see shapes everywhere. 699 00:38:31,375 --> 00:38:34,208 We see that all the planets are going around the Sun 700 00:38:34,278 --> 00:38:35,836 in a shape called an ellipse. 701 00:38:35,913 --> 00:38:38,279 It just looks like the stretched circle. 702 00:38:38,349 --> 00:38:40,783 And anything orbiting anything out there in the Universe, 703 00:38:40,851 --> 00:38:42,079 why is it always that shape? 704 00:38:42,153 --> 00:38:44,678 You know, not a figure eight or a square? 705 00:38:44,755 --> 00:38:47,553 As soon as we scratch beneath the surface, 706 00:38:47,625 --> 00:38:51,117 we start to discover all these patterns and regularities 707 00:38:51,195 --> 00:38:52,560 and even numbers. 708 00:38:52,630 --> 00:38:54,928 Like, if I just pick up some sticks here, 709 00:38:54,999 --> 00:38:57,559 and I ask, like, how many sticks can I put here 710 00:38:57,635 --> 00:38:59,865 which are perpendicular to each other? 711 00:38:59,937 --> 00:39:02,098 I get a number. I get three. 712 00:39:02,173 --> 00:39:04,107 We have a fancy number for this in physics. 713 00:39:04,175 --> 00:39:06,643 We call it the dimensionality of space. 714 00:39:06,711 --> 00:39:10,078 And these numbers that are built into nature are very important, 715 00:39:10,147 --> 00:39:11,876 because if you tweak them a little bit, 716 00:39:11,949 --> 00:39:13,940 if you say the proton isn't 717 00:39:14,018 --> 00:39:16,543 1,836 times heavier than an electron, 718 00:39:16,620 --> 00:39:21,319 but 5,000 times heavier, for instance, we would die. 719 00:39:21,392 --> 00:39:23,656 In fact, if you change many of the numbers 720 00:39:23,728 --> 00:39:25,252 by just a few percent, 721 00:39:25,329 --> 00:39:28,696 the Sun might blow up or suddenly atoms would collapse 722 00:39:28,766 --> 00:39:32,566 and life as we know it just wouldn't be possible. 723 00:39:32,636 --> 00:39:34,763 So, not only are these numbers there, 724 00:39:34,839 --> 00:39:36,932 but they're extremely important 725 00:39:37,007 --> 00:39:42,138 for understanding the very essence of our reality. 726 00:39:42,213 --> 00:39:46,707 Freeman: This brings us back to an uncomfortable notion 727 00:39:46,784 --> 00:39:49,617 suggested by the prevailing theory of quantum mechanics. 728 00:39:49,687 --> 00:39:53,248 At the deepest level of reality, 729 00:39:53,324 --> 00:39:55,451 nothing is solid. 730 00:39:55,526 --> 00:39:57,551 There is only information - 731 00:39:57,628 --> 00:40:00,153 numbers adhering to a set of rules 732 00:40:00,231 --> 00:40:03,758 we don't yet understand. 733 00:40:03,834 --> 00:40:06,359 Tegmark: The only properties an electron has 734 00:40:06,437 --> 00:40:08,234 is a bunch of numbers. 735 00:40:08,305 --> 00:40:11,604 We physicists have names for them like spin and charge, 736 00:40:11,675 --> 00:40:13,700 but they're really just numbers. 737 00:40:13,778 --> 00:40:16,246 There's really nothing there at the bottom level 738 00:40:16,313 --> 00:40:19,749 except numbers, except math. 739 00:40:22,253 --> 00:40:25,086 Freeman: Math may be the ultimate truth, 740 00:40:25,156 --> 00:40:26,885 but given our limitations 741 00:40:26,957 --> 00:40:30,984 and how vast and strange so much of nature seems to be, 742 00:40:31,061 --> 00:40:34,758 is it even possible to solve this problem? 743 00:40:34,832 --> 00:40:39,735 Can we ever know how the Universe really works? 744 00:40:39,804 --> 00:40:41,328 There's certainly no guarantee 745 00:40:41,405 --> 00:40:43,498 that we'll find the ultimate equation, 746 00:40:43,574 --> 00:40:46,907 but I think we do have a shot at it. 747 00:40:46,977 --> 00:40:49,445 It's really remarkable how far we've come as a species 748 00:40:49,513 --> 00:40:51,071 in the last 100 years, 749 00:40:51,148 --> 00:40:54,709 beyond our wildest dreams in understanding stuff. 750 00:40:54,785 --> 00:40:58,152 And there's no better way to guarantee we're gonna fail 751 00:40:58,222 --> 00:41:00,190 than to not try. 752 00:41:00,257 --> 00:41:01,952 If I'm wrong 753 00:41:02,026 --> 00:41:04,517 and there is something inherently nonmathematical 754 00:41:04,595 --> 00:41:06,062 about the Universe, 755 00:41:06,130 --> 00:41:07,927 then physics is ultimately doomed. 756 00:41:07,998 --> 00:41:09,465 We're gonna reach a roadblock 757 00:41:09,533 --> 00:41:11,524 beyond which you just can't proceed. 758 00:41:11,602 --> 00:41:12,762 Whereas, if I'm right, 759 00:41:12,837 --> 00:41:15,431 that would actually be a very happy situation 760 00:41:15,506 --> 00:41:16,996 where there is no roadblock 761 00:41:17,074 --> 00:41:21,636 and our progress would only be limited by our own imagination. 762 00:41:25,549 --> 00:41:30,009 Will we ever see the entire web of reality? 763 00:41:30,087 --> 00:41:34,183 Can we find, and will we understand, 764 00:41:34,258 --> 00:41:36,419 the ultimate truth? 765 00:41:36,494 --> 00:41:39,327 Right now, we are like archaeologists 766 00:41:39,396 --> 00:41:43,196 who have uncovered a small triangle buried in the sand, 767 00:41:43,267 --> 00:41:47,795 the tip of an enormous pyramid that we can't yet see. 768 00:41:47,872 --> 00:41:49,567 Perhaps it's presumptuous 769 00:41:49,640 --> 00:41:52,404 for human beings to think we ever will. 770 00:41:52,476 --> 00:41:55,741 But we continue to uncover the truth, 771 00:41:55,813 --> 00:41:59,715 bit by bit, piece by piece. 772 00:41:59,783 --> 00:42:01,944 If we keep digging, 773 00:42:02,019 --> 00:42:06,388 we may finally reveal the full beauty of creation... 774 00:42:06,457 --> 00:42:11,759 and perhaps steal a glimpse into the mind of God.