WEBVTT 00:00:07.187 --> 00:00:11.372 There is something about physics 00:00:11.396 --> 00:00:15.396 that has been really bothering me since I was a little kid. 00:00:17.110 --> 00:00:18.919 And it's related to a question 00:00:18.943 --> 00:00:22.187 that scientists have been asking for almost 100 years, 00:00:22.211 --> 00:00:23.380 with no answer. 00:00:25.208 --> 00:00:28.218 How do the smallest things in nature, 00:00:28.242 --> 00:00:30.395 the particles of the quantum world, 00:00:30.419 --> 00:00:33.450 match up with the largest things in nature -- 00:00:33.474 --> 00:00:36.721 planets and stars and galaxies held together by gravity? 00:00:37.350 --> 00:00:40.123 As a kid, I would puzzle over questions just like this. 00:00:40.147 --> 00:00:43.039 I would fiddle around with microscopes and electromagnets, 00:00:43.063 --> 00:00:45.258 and I would read about the forces of the small 00:00:45.282 --> 00:00:46.616 and about quantum mechanics 00:00:46.640 --> 00:00:50.204 and I would marvel at how well that description matched up 00:00:50.228 --> 00:00:51.398 to our observation. 00:00:52.320 --> 00:00:53.903 Then I would look at the stars, 00:00:53.927 --> 00:00:56.451 and I would read about how well we understand gravity, 00:00:56.475 --> 00:00:59.825 and I would think surely, there must be some elegant way 00:00:59.849 --> 00:01:02.494 that these two systems match up. 00:01:03.121 --> 00:01:04.522 But there's not. 00:01:05.773 --> 00:01:06.933 And the books would say, 00:01:06.957 --> 00:01:10.140 yeah, we understand a lot about these two realms separately, 00:01:10.164 --> 00:01:12.774 but when we try to link them mathematically, 00:01:12.798 --> 00:01:14.128 everything breaks. 00:01:14.974 --> 00:01:16.284 And for 100 years, 00:01:16.308 --> 00:01:21.336 none of our ideas as to how to solve this basically physics disaster, 00:01:21.360 --> 00:01:23.174 has ever been supported by evidence. 00:01:24.471 --> 00:01:26.125 And to little old me -- 00:01:26.149 --> 00:01:27.959 little, curious, skeptical James -- 00:01:27.983 --> 00:01:30.851 this was a supremely unsatisfying answer. 00:01:32.211 --> 00:01:34.444 So, I'm still a skeptical little kid. 00:01:34.468 --> 00:01:38.278 Flash-forward now to December of 2015, 00:01:39.129 --> 00:01:41.603 when I found myself smack in the middle 00:01:41.627 --> 00:01:44.567 of the physics world being flipped on its head. 00:01:46.099 --> 00:01:49.419 It all started when we at CERN saw something intriguing in our data: 00:01:49.443 --> 00:01:51.717 a hint of a new particle, 00:01:51.741 --> 00:01:55.957 an inkling of a possibly extraordinary answer to this question. 00:01:57.877 --> 00:02:00.004 So I'm still a skeptical little kid, I think, 00:02:00.028 --> 00:02:02.161 but I'm also now a particle hunter. 00:02:02.185 --> 00:02:05.648 I am a physicist at CERN's Large Hadron Collider, 00:02:05.672 --> 00:02:09.143 the largest science experiment ever mounted. 00:02:09.977 --> 00:02:13.512 It's a 27-kilometer tunnel on the border of France and Switzerland 00:02:13.536 --> 00:02:15.386 buried 100 meters underground. 00:02:15.410 --> 00:02:16.564 And in this tunnel, 00:02:16.588 --> 00:02:20.541 we use superconducting magnets colder than outer space 00:02:20.565 --> 00:02:23.626 to accelerate protons to almost the speed of light 00:02:23.650 --> 00:02:27.527 and slam them into each other millions of times per second, 00:02:27.551 --> 00:02:30.377 collecting the debris of these collisions 00:02:30.401 --> 00:02:34.372 to search for new, undiscovered fundamental particles. 00:02:34.827 --> 00:02:37.291 Its design and construction took decades of work 00:02:37.315 --> 00:02:40.347 by thousands of physicists from around the globe, 00:02:40.371 --> 00:02:42.912 and in the summer of 2015, 00:02:42.936 --> 00:02:46.360 we had been working tirelessly to switch on the LHC 00:02:46.384 --> 00:02:50.851 at the highest energy that humans have ever used in a collider experiment. 00:02:51.835 --> 00:02:54.358 Now, higher energy is important 00:02:54.382 --> 00:02:56.569 because for particles, there is an equivalence 00:02:56.593 --> 00:02:58.794 between energy and particle mass, 00:02:58.818 --> 00:03:01.279 and mass is just a number put there by nature. 00:03:02.168 --> 00:03:03.486 To discover new particles, 00:03:03.510 --> 00:03:05.632 we need to reach these bigger numbers. 00:03:05.656 --> 00:03:08.910 And to do that, we have to build a bigger, higher energy collider, 00:03:08.934 --> 00:03:11.499 and the biggest, highest energy collider in the world 00:03:11.523 --> 00:03:12.989 is the Large Hadron Collider. 00:03:14.371 --> 00:03:19.270 And then, we collide protons quadrillions of times, 00:03:19.294 --> 00:03:23.578 and we collect this data very slowly, over months and months. 00:03:24.913 --> 00:03:29.248 And then new particles might show up in our data as bumps -- 00:03:29.272 --> 00:03:31.717 slight deviations from what you expect, 00:03:31.741 --> 00:03:35.708 little clusters of data points that make a smooth line not so smooth. 00:03:36.479 --> 00:03:38.200 For example, this bump, 00:03:39.110 --> 00:03:41.643 after months of data-taking in 2012, 00:03:41.667 --> 00:03:43.796 led to the discovery of the Higgs particle -- 00:03:43.820 --> 00:03:45.025 the Higgs boson -- 00:03:45.049 --> 00:03:48.414 and to a Nobel Prize for the confirmation of its existence. 00:03:50.072 --> 00:03:53.630 This jump up in energy in 2015 00:03:54.728 --> 00:03:58.020 represented the best chance that we as a species had ever had 00:03:58.044 --> 00:03:59.521 of discovering new particles -- 00:03:59.545 --> 00:04:01.657 new answers to these long-standing questions, 00:04:01.681 --> 00:04:04.778 because it was almost twice as much energy as we used 00:04:04.802 --> 00:04:06.724 when we discovered the Higgs boson. 00:04:06.748 --> 00:04:10.489 Many of my colleagues had been working their entire careers for this moment, 00:04:10.513 --> 00:04:12.589 and frankly, to little curious me, 00:04:12.613 --> 00:04:15.523 this was the moment I'd been waiting for my entire life. 00:04:15.547 --> 00:04:17.278 So 2015 was go time. 00:04:18.754 --> 00:04:20.964 So June 2015, 00:04:21.822 --> 00:04:24.481 the LHC is switched back on. 00:04:25.140 --> 00:04:28.017 My colleagues and I held our breath and bit our fingernails, 00:04:28.041 --> 00:04:30.552 and then finally we saw the first proton collisions 00:04:30.576 --> 00:04:32.532 at this highest energy ever. 00:04:32.556 --> 00:04:34.632 Applause, champagne, celebration. 00:04:34.656 --> 00:04:38.252 This was a milestone for science, 00:04:38.276 --> 00:04:42.898 and we had no idea what we would find in this brand-new data. 00:04:46.090 --> 00:04:48.268 And then a few weeks later, we found a bump. 00:04:50.292 --> 00:04:51.968 It wasn't a very big bump, 00:04:53.052 --> 00:04:55.564 but it was big enough to make you raise your eyebrow. 00:04:55.588 --> 00:04:57.839 But on a scale of one to 10 for eyebrow raises, 00:04:57.863 --> 00:05:00.473 if 10 indicates that you've discovered a new particle, 00:05:00.497 --> 00:05:02.224 this eyebrow raise is about a four. 00:05:02.248 --> 00:05:03.398 (Laughter) 00:05:04.532 --> 00:05:09.743 I spent hours, days, weeks in secret meetings, 00:05:09.767 --> 00:05:12.127 arguing with my colleagues over this little bump, 00:05:12.151 --> 00:05:15.387 poking and prodding it with our most ruthless experimental sticks 00:05:15.411 --> 00:05:17.388 to see if it would withstand scrutiny. 00:05:18.088 --> 00:05:21.549 But even after months of working feverishly -- 00:05:21.573 --> 00:05:24.005 sleeping in our offices and not going home, 00:05:24.029 --> 00:05:26.106 candy bars for dinner, 00:05:26.130 --> 00:05:27.700 coffee by the bucketful -- 00:05:27.724 --> 00:05:31.967 physicists are machines for turning coffee into diagrams -- 00:05:31.991 --> 00:05:33.390 (Laughter) 00:05:33.414 --> 00:05:35.950 This little bump would not go away. 00:05:36.804 --> 00:05:38.942 So after a few months, 00:05:38.966 --> 00:05:42.676 we presented our little bump to the world with a very clear message: 00:05:43.557 --> 00:05:46.268 this little bump is interesting but it's not definitive, 00:05:46.292 --> 00:05:49.621 so let's keep an eye on it as we take more data. 00:05:49.972 --> 00:05:52.263 So we were trying to be extremely cool about it. 00:05:53.563 --> 00:05:55.751 And the world ran with it anyway. 00:05:56.483 --> 00:05:58.115 The news loved it. 00:05:58.835 --> 00:06:01.390 People said it reminded them of the little bump 00:06:01.414 --> 00:06:04.837 that was shown on the way toward the Higgs boson discovery. 00:06:04.861 --> 00:06:07.989 Better than that, my theorist colleagues -- 00:06:08.648 --> 00:06:10.965 I love my theorist colleagues -- 00:06:10.989 --> 00:06:14.601 my theorist colleagues wrote 500 papers about this little bump. 00:06:14.625 --> 00:06:16.080 (Laughter) 00:06:16.674 --> 00:06:20.640 The world of particle physics had been flipped on its head. 00:06:21.845 --> 00:06:26.087 But what was it about this particular bump 00:06:26.111 --> 00:06:30.201 that caused thousands of physicists to collectively lose their cool? 00:06:31.696 --> 00:06:33.132 This little bump was unique. 00:06:34.298 --> 00:06:35.667 This little bump indicated 00:06:35.691 --> 00:06:38.713 that we were seeing an unexpectedly large number of collisions 00:06:38.737 --> 00:06:42.068 whose debris consisted of only two photons, 00:06:42.092 --> 00:06:43.336 two particles of light. 00:06:43.360 --> 00:06:44.597 And that's rare. 00:06:45.169 --> 00:06:47.789 Particle collisions are not like automobile collisions. 00:06:47.813 --> 00:06:49.332 They have different rules. 00:06:49.356 --> 00:06:52.006 When two particles collide at almost the speed of light, 00:06:52.030 --> 00:06:53.451 the quantum world takes over. 00:06:53.475 --> 00:06:54.735 And in the quantum world, 00:06:54.759 --> 00:06:57.952 these two particles can briefly create a new particle 00:06:57.976 --> 00:07:00.756 that lives for a tiny fraction of a second 00:07:00.780 --> 00:07:03.661 before splitting into other particles that hit our detector. 00:07:03.685 --> 00:07:07.090 Imagine a car collision where the two cars vanish upon impact, 00:07:07.114 --> 00:07:09.383 a bicycle appears in their place -- 00:07:09.407 --> 00:07:10.478 (Laughter) 00:07:10.502 --> 00:07:12.963 And then that bicycle explodes into two skateboards, 00:07:12.987 --> 00:07:14.168 which hit our detector. 00:07:14.192 --> 00:07:15.571 (Laughter) 00:07:15.595 --> 00:07:17.548 Hopefully, not literally. 00:07:17.572 --> 00:07:18.914 They're very expensive. 00:07:20.291 --> 00:07:24.039 Events where only two photons hit out detector are very rare. 00:07:24.063 --> 00:07:27.785 And because of the special quantum properties of photons, 00:07:27.809 --> 00:07:31.597 there's a very small number of possible new particles -- 00:07:31.621 --> 00:07:33.118 these mythical bicycles -- 00:07:33.142 --> 00:07:35.385 that can give birth to only two photons. 00:07:35.912 --> 00:07:38.748 But one of these options is huge, 00:07:38.772 --> 00:07:41.608 and it has to do with that long-standing question 00:07:41.632 --> 00:07:44.154 that bothered me as a tiny little kid, 00:07:44.178 --> 00:07:45.538 about gravity. 00:07:48.046 --> 00:07:50.718 Gravity may seem super strong to you, 00:07:50.742 --> 00:07:54.842 but it's actually crazily weak compared to the other forces of nature. 00:07:54.866 --> 00:07:57.497 I can briefly beat gravity when I jump, 00:07:58.490 --> 00:08:01.333 but I can't pick a proton out of my hand. 00:08:02.563 --> 00:08:05.779 The strength of gravity compared to the other forces of nature? 00:08:06.580 --> 00:08:08.770 It's 10 to the minus 39. 00:08:08.794 --> 00:08:11.331 That's a decimal with 39 zeros after it. 00:08:11.355 --> 00:08:12.512 Worse than that, 00:08:12.536 --> 00:08:15.563 all of the other known forces of nature are perfectly described 00:08:15.587 --> 00:08:17.624 by this thing we call the Standard Model, 00:08:17.648 --> 00:08:21.083 which is our current best description of nature at its smallest scales, 00:08:21.107 --> 00:08:22.263 and quite frankly, 00:08:22.287 --> 00:08:26.464 one of the most successful achievements of humankind -- 00:08:26.488 --> 00:08:30.500 except for gravity, which is absent from the Standard Model. 00:08:30.524 --> 00:08:31.674 It's crazy. 00:08:32.145 --> 00:08:35.246 It's almost as though most of gravity has gone missing. 00:08:36.494 --> 00:08:38.160 We feel a little bit of it, 00:08:38.184 --> 00:08:39.861 but where's the rest of it? 00:08:39.885 --> 00:08:41.167 No one knows. 00:08:42.102 --> 00:08:46.506 But one theoretical explanation proposes a wild solution. 00:08:48.220 --> 00:08:49.559 You and I -- 00:08:49.583 --> 00:08:51.161 even you in the back -- 00:08:51.185 --> 00:08:53.330 we live in three dimensions of space. 00:08:53.354 --> 00:08:55.911 I hope that's a non-controversial statement. 00:08:55.935 --> 00:08:57.764 (Laughter) 00:08:57.788 --> 00:09:01.226 All of the known particles also live in three dimensions of space. 00:09:01.250 --> 00:09:03.440 In fact, a particle is just another name 00:09:03.464 --> 00:09:06.473 for an excitation in a three-dimensional field; 00:09:06.497 --> 00:09:08.417 a localized wobbling in space. 00:09:09.388 --> 00:09:12.917 More importantly, all the math that we use to describe all this stuff 00:09:12.941 --> 00:09:16.014 assumes that there are only three dimensions of space. 00:09:16.038 --> 00:09:19.419 But math is math, and we can play around with our math however we want. 00:09:19.443 --> 00:09:22.609 And people have been playing around with extra dimensions of space 00:09:22.633 --> 00:09:23.788 for a very long time, 00:09:23.812 --> 00:09:26.397 but it's always been an abstract mathematical concept. 00:09:26.421 --> 00:09:29.593 I mean, just look around you -- you at the back, look around -- 00:09:29.617 --> 00:09:31.898 there's clearly only three dimensions of space. 00:09:33.054 --> 00:09:34.613 But what if that's not true? 00:09:36.209 --> 00:09:42.464 What if the missing gravity is leaking into an extra-spatial dimension 00:09:42.488 --> 00:09:44.444 that's invisible to you and I? 00:09:45.455 --> 00:09:48.549 What if gravity is just as strong as the other forces 00:09:48.573 --> 00:09:51.714 if you were to view it in this extra-spatial dimension, 00:09:51.738 --> 00:09:54.638 and what you and I experience is a tiny slice of gravity 00:09:54.662 --> 00:09:56.559 make it seem very weak? 00:09:58.258 --> 00:09:59.433 If this were true, 00:09:59.457 --> 00:10:02.205 we would have to expand our Standard Model of particles 00:10:02.229 --> 00:10:06.315 to include an extra particle, a hyperdimensional particle of gravity, 00:10:06.339 --> 00:10:09.334 a special graviton that lives in extra-spatial dimensions. 00:10:09.358 --> 00:10:10.823 I see the looks on your faces. 00:10:10.847 --> 00:10:12.666 You should be asking me the question, 00:10:12.690 --> 00:10:16.334 "How in the world are we going to test this crazy, science fiction idea, 00:10:16.358 --> 00:10:18.849 stuck as we are in three dimensions?" 00:10:18.873 --> 00:10:20.155 The way we always do, 00:10:20.179 --> 00:10:22.318 by slamming together two protons -- 00:10:22.342 --> 00:10:23.494 (Laughter) 00:10:23.518 --> 00:10:26.082 Hard enough that the collision reverberates 00:10:26.106 --> 00:10:28.797 into any extra-spatial dimensions that might be there, 00:10:28.821 --> 00:10:31.420 momentarily creating this hyperdimensional graviton 00:10:31.444 --> 00:10:35.824 that then snaps back into the three dimensions of the LHC 00:10:35.848 --> 00:10:37.670 and spits off two photons, 00:10:38.378 --> 00:10:39.716 two particles of light. 00:10:41.517 --> 00:10:44.427 And this hypothetical, extra-dimensional graviton 00:10:44.451 --> 00:10:48.158 is one of the only possible, hypothetical new particles 00:10:48.182 --> 00:10:50.317 that has the special quantum properties 00:10:50.341 --> 00:10:54.577 that could give birth to our little, two-photon bump. 00:10:56.100 --> 00:11:01.920 So, the possibility of explaining the mysteries of gravity 00:11:01.944 --> 00:11:05.442 and of discovering extra dimensions of space -- 00:11:05.466 --> 00:11:07.058 perhaps now you get a sense 00:11:07.082 --> 00:11:11.206 as to why thousands of physics geeks collectively lost their cool 00:11:11.230 --> 00:11:13.112 over our little, two-photon bump. 00:11:13.136 --> 00:11:16.036 A discovery of this type would rewrite the textbooks. 00:11:16.839 --> 00:11:17.991 But remember, 00:11:18.015 --> 00:11:19.739 the message from us experimentalists 00:11:19.763 --> 00:11:22.002 that actually were doing this work at the time, 00:11:22.026 --> 00:11:23.180 was very clear: 00:11:23.204 --> 00:11:24.378 we need more data. 00:11:24.402 --> 00:11:25.921 With more data, 00:11:25.945 --> 00:11:29.969 the little bump will either turn into a nice, crisp Nobel Prize -- 00:11:29.993 --> 00:11:31.753 (Laughter) 00:11:31.777 --> 00:11:34.741 Or the extra data will fill in the space around the bump 00:11:34.765 --> 00:11:36.631 and turn it into a nice, smooth line. 00:11:37.615 --> 00:11:38.833 So we took more data, 00:11:38.857 --> 00:11:41.434 and with five times the data, several months later, 00:11:41.458 --> 00:11:43.148 our little bump 00:11:43.172 --> 00:11:45.520 turned into a smooth line. 00:11:49.317 --> 00:11:52.801 The news reported on a "huge disappointment," on "faded hopes," 00:11:52.825 --> 00:11:55.335 and on particle physicists "being sad." 00:11:55.359 --> 00:11:57.170 Given the tone of the coverage, 00:11:57.194 --> 00:12:00.682 you'd think that we had decided to shut down the LHC and go home. 00:12:00.706 --> 00:12:01.856 (Laughter) 00:12:02.728 --> 00:12:04.331 But that's not what we did. 00:12:07.157 --> 00:12:09.171 But why not? 00:12:10.575 --> 00:12:13.420 I mean, if I didn't discover a particle -- and I didn't -- 00:12:14.309 --> 00:12:17.338 if I didn't discover a particle, why am I here talking to you? 00:12:17.362 --> 00:12:19.799 Why didn't I just hang my head in shame 00:12:19.823 --> 00:12:21.047 and go home? 00:12:25.269 --> 00:12:28.620 Particle physicists are explorers. 00:12:29.521 --> 00:12:32.473 And very much of what we do is cartography. 00:12:33.568 --> 00:12:36.420 Let me put it this way: forget about the LHC for a second. 00:12:36.444 --> 00:12:39.826 Imagine you are a space explorer arriving at a distant planet, 00:12:39.850 --> 00:12:41.175 searching for aliens. 00:12:41.199 --> 00:12:42.721 What is your first task? 00:12:44.031 --> 00:12:47.107 To immediately orbit the planet, land, take a quick look around 00:12:47.131 --> 00:12:49.017 for any big, obvious signs of life, 00:12:49.041 --> 00:12:50.860 and report back to home base. 00:12:50.884 --> 00:12:52.508 That's the stage we're at now. 00:12:53.369 --> 00:12:54.856 We took a first look at the LHC 00:12:54.880 --> 00:12:57.164 for any new, big, obvious-to-spot particles, 00:12:57.188 --> 00:12:59.138 and we can report that there are none. 00:12:59.731 --> 00:13:02.404 We saw a weird-looking alien bump on a distant mountain, 00:13:02.428 --> 00:13:04.598 but once we got closer, we saw it was a rock. 00:13:04.916 --> 00:13:07.556 But then what do we do? Do we just give up and fly away? 00:13:07.580 --> 00:13:08.867 Absolutely not; 00:13:08.891 --> 00:13:11.196 we would be terrible scientists if we did. 00:13:11.220 --> 00:13:14.833 No, we spend the next couple of decades exploring, 00:13:14.857 --> 00:13:16.337 mapping out the territory, 00:13:16.361 --> 00:13:18.726 sifting through the sand with a fine instrument, 00:13:18.750 --> 00:13:20.208 peeking under every stone, 00:13:20.232 --> 00:13:21.786 drilling under the surface. 00:13:22.206 --> 00:13:24.799 New particles can either show up immediately 00:13:24.823 --> 00:13:26.956 as big, obvious-to-spot bumps, 00:13:26.980 --> 00:13:30.921 or they can only reveal themselves after years of data taking. 00:13:32.203 --> 00:13:36.613 Humanity has just begun its exploration at the LHC at this big high energy, 00:13:36.637 --> 00:13:38.428 and we have much searching to do. 00:13:38.452 --> 00:13:44.277 But what if, even after 10 or 20 years, we still find no new particles? 00:13:45.153 --> 00:13:46.848 We build a bigger machine. 00:13:46.872 --> 00:13:48.446 (Laughter) 00:13:48.470 --> 00:13:50.160 We search at higher energies. 00:13:50.576 --> 00:13:52.146 We search at higher energies. 00:13:53.046 --> 00:13:56.099 Planning is already underway for a 100-kilometer tunnel 00:13:56.712 --> 00:13:59.688 that will collide particles at 10 times the energy of the LHC. 00:13:59.712 --> 00:14:02.049 We don't decide where nature places new particles. 00:14:02.466 --> 00:14:04.112 We only decide to keep exploring. 00:14:04.136 --> 00:14:06.694 But what if, even after a 100-kilometer tunnel 00:14:06.718 --> 00:14:08.578 or a 500-kilometer tunnel 00:14:08.602 --> 00:14:11.443 or a 10,000-kilometer collider floating in space 00:14:11.467 --> 00:14:13.045 between the Earth and the Moon, 00:14:13.069 --> 00:14:16.131 we still find no new particles? 00:14:17.697 --> 00:14:20.391 Then perhaps we're doing particle physics wrong. 00:14:20.415 --> 00:14:22.206 (Laughter) 00:14:22.230 --> 00:14:24.187 Perhaps we need to rethink things. 00:14:25.227 --> 00:14:28.489 Maybe we need more resources, technology, expertise 00:14:28.513 --> 00:14:30.021 than what we currently have. 00:14:30.710 --> 00:14:34.051 We already use artificial intelligence and machine learning techniques 00:14:34.075 --> 00:14:35.228 in parts of the LHC, 00:14:35.252 --> 00:14:37.658 but imagine designing a particle physics experiment 00:14:37.682 --> 00:14:39.351 using such sophisticated algorithms 00:14:39.375 --> 00:14:42.543 that it could teach itself to discover a hyperdimensional graviton. 00:14:42.567 --> 00:14:43.724 But what if? 00:14:43.748 --> 00:14:45.193 What if the ultimate question: 00:14:45.217 --> 00:14:48.690 What if even artificial intelligence can't help us answer our questions? 00:14:48.714 --> 00:14:50.825 What if these open questions, for centuries, 00:14:50.849 --> 00:14:53.518 are destined to be unanswered for the foreseeable future? 00:14:53.542 --> 00:14:56.471 What if the stuff that's bothered me since I was a little kid 00:14:56.495 --> 00:14:59.018 is destined to be unanswered in my lifetime? 00:15:00.495 --> 00:15:01.651 Then that ... 00:15:02.382 --> 00:15:04.476 will be even more fascinating. 00:15:06.244 --> 00:15:09.469 We will be forced to think in completely new ways. 00:15:10.461 --> 00:15:12.519 We'll have to go back to our assumptions, 00:15:12.543 --> 00:15:14.882 and determine if there was a flaw somewhere. 00:15:15.501 --> 00:15:18.896 And we'll need to encourage more people to join us in studying science 00:15:18.920 --> 00:15:21.982 since we need fresh eyes on these century-old problems. 00:15:22.006 --> 00:15:25.140 I don't have the answers, and I'm still searching for them. 00:15:25.164 --> 00:15:27.493 But someone -- maybe she's in school right now, 00:15:27.517 --> 00:15:29.201 maybe she's not even born yet -- 00:15:29.883 --> 00:15:33.016 could eventually guide us to see physics in a completely new way, 00:15:33.040 --> 00:15:37.308 and to point out that perhaps we're just asking the wrong questions. 00:15:38.212 --> 00:15:40.622 Which would not be the end of physics, 00:15:40.646 --> 00:15:42.052 but a novel beginning. 00:15:43.304 --> 00:15:44.454 Thank you. 00:15:44.478 --> 00:15:47.019 (Applause)