WEBVTT 00:00:21.745 --> 00:00:23.096 I want to ask you something: 00:00:23.096 --> 00:00:25.578 When was the last time you watched the stars? 00:00:25.578 --> 00:00:27.861 I know most people forget they exist 00:00:27.861 --> 00:00:30.061 specially in this polluted city 00:00:30.061 --> 00:00:32.598 which is sometimes foggy, 00:00:32.598 --> 00:00:34.092 we never see them. 00:00:34.092 --> 00:00:36.436 But since I was a kid, maybe not that young, 00:00:36.436 --> 00:00:38.120 maybe 12 or 13 years, 00:00:38.120 --> 00:00:41.481 I've been captivated by stars and would watch them whenever possible. 00:00:41.481 --> 00:00:43.808 My dad gave me a small telescope 00:00:43.808 --> 00:00:46.806 by the time I was 14 and I spent hours 00:00:46.806 --> 00:00:48.965 watching planets and stars 00:00:48.965 --> 00:00:50.349 and always wondering: 00:00:50.349 --> 00:00:51.773 What is out there? 00:00:51.773 --> 00:00:54.747 Is there someone watching me back 00:00:54.747 --> 00:00:56.936 with a telescope, wondering what is out here? 00:00:57.508 --> 00:00:59.966 This allure went on for years 00:00:59.966 --> 00:01:02.388 and at some point I decided to be an astronomer. 00:01:03.102 --> 00:01:05.820 In Mexico, in order to be an astronomer you need to be a physicist. 00:01:05.820 --> 00:01:07.724 So I studied physics. 00:01:07.724 --> 00:01:10.618 I never got to be an astronomer, now I'm something in between, 00:01:10.893 --> 00:01:13.203 half an astrophysicist, half a physicist 00:01:13.203 --> 00:01:14.837 but this idea of stars 00:01:14.837 --> 00:01:16.848 and the possibility of reaching them 00:01:16.848 --> 00:01:18.251 remained with me. 00:01:18.584 --> 00:01:20.692 When I started my major in physics 00:01:20.692 --> 00:01:23.232 I realized something many of you 00:01:23.232 --> 00:01:26.065 have heard of, even if you are not totally clear about it: 00:01:26.555 --> 00:01:30.564 that more than 100 years ago, in 1905, 00:01:30.564 --> 00:01:32.432 this guy named Albert Einstein, 00:01:32.432 --> 00:01:35.155 discovered that light speed 00:01:35.155 --> 00:01:37.792 is the fastest in the universe. 00:01:37.792 --> 00:01:39.187 That might not say you a lot 00:01:39.187 --> 00:01:41.400 because light speed is huge. 00:01:41.400 --> 00:01:44.583 Light moves up to 186,000 mi/s 00:01:44.583 --> 00:01:47.657 so high a speed that we can phone call 00:01:47.657 --> 00:01:49.837 someone in India or Japan 00:01:49.837 --> 00:01:52.389 with no problem at all. 00:01:52.389 --> 00:01:55.795 Even astronauts who went to the moon 40 years ago 00:01:56.825 --> 00:02:00.556 were interviewed and the President could talk to them 00:02:00.556 --> 00:02:03.834 with no evident delay 00:02:03.834 --> 00:02:06.331 even though the astronauts were in the moon, 00:02:06.331 --> 00:02:09.473 thing is that light speed is huge 00:02:09.473 --> 00:02:12.592 and the universe gigantic. 00:02:13.759 --> 00:02:16.376 We cannot travel faster than light speed 00:02:16.376 --> 00:02:18.231 and that is a severe problem 00:02:18.231 --> 00:02:20.589 to reach for the stars. 00:02:20.589 --> 00:02:23.354 Sun is 8 light-minutes away, 00:02:23.354 --> 00:02:25.707 that is, it takes 8 minutes for light 00:02:25.707 --> 00:02:28.382 to get here from the Sun, from the Sun to us. 00:02:28.382 --> 00:02:29.988 If the Sun exploded right now, 00:02:29.988 --> 00:02:32.273 nobody would notice up until eight minutes later. 00:02:33.269 --> 00:02:35.677 The closest star after the Sun 00:02:35.677 --> 00:02:37.779 is Alfa Centauri, 00:02:37.779 --> 00:02:40.138 it takes four years for light to travel 00:02:40.138 --> 00:02:41.626 and it's right besides the Sun. 00:02:42.057 --> 00:02:43.483 We live in a galaxy 00:02:43.493 --> 00:02:46.487 that is a star spiral called Milky Way. 00:02:46.487 --> 00:02:49.662 The center of our galaxy was 30,000 light years away, 00:02:49.662 --> 00:02:52.160 it takes 30,000 light years for light to travel 00:02:52.160 --> 00:02:54.765 from the center of the galaxy to us, 00:02:54.765 --> 00:02:56.582 and two million years 00:02:56.582 --> 00:02:58.495 in traveling from Andromeda galaxy 00:02:58.495 --> 00:03:01.464 that is one of our neighbor galaxies. 00:03:01.624 --> 00:03:04.254 The universe is huge, vast, 00:03:04.254 --> 00:03:06.732 if we ever want to reach the stars 00:03:06.732 --> 00:03:09.583 the light limit is very serious, 00:03:09.583 --> 00:03:11.973 a very serious problem, but why? 00:03:12.620 --> 00:03:14.913 Why we cannot travel faster than light? 00:03:14.923 --> 00:03:16.901 And it's not because Einstein said so, 00:03:16.901 --> 00:03:18.767 that is no how science works. 00:03:18.767 --> 00:03:21.053 In science there is no authority principle; 00:03:21.053 --> 00:03:23.116 it's not because some famous guy says so. 00:03:23.623 --> 00:03:25.635 There are reasons, theoretical reasons, 00:03:25.635 --> 00:03:27.715 observational reasons, 00:03:27.715 --> 00:03:29.413 experiments show it, 00:03:29.413 --> 00:03:32.592 it is a verified fact, 00:03:32.592 --> 00:03:33.971 but why? 00:03:34.285 --> 00:03:38.384 Basically, the answer is that theory of relativity prevents it, 00:03:38.384 --> 00:03:40.179 so I will tell you a bit, 00:03:40.179 --> 00:03:42.489 a very quick course: 00:03:42.489 --> 00:03:45.612 Relativity in a couple of minutes. 00:03:45.612 --> 00:03:48.625 Don't be afraid, I'll give a general overview, 00:03:48.625 --> 00:03:51.992 normally it takes six months to teach this 00:03:51.992 --> 00:03:54.561 to sixth and seventh graders of physics major. 00:03:54.561 --> 00:03:56.854 So right now I will explain it 00:03:56.854 --> 00:03:59.276 in two minutes and for non-physicists. 00:03:59.276 --> 00:04:01.036 So, don't worry. 00:04:02.639 --> 00:04:05.036 Relativity is an old concept 00:04:05.036 --> 00:04:07.428 though it wasn't called like that. 00:04:07.428 --> 00:04:10.951 The concept can be traced back from Galileo Galilei 00:04:10.951 --> 00:04:14.252 around 1620, in the 17th century. 00:04:14.667 --> 00:04:17.939 Galileo was the first one to realize something interesting, 00:04:17.939 --> 00:04:20.224 when it comes to movement, when I move, 00:04:20.224 --> 00:04:23.342 my movement is always relative to something else. 00:04:23.342 --> 00:04:25.491 Movement is said to be relative, 00:04:25.491 --> 00:04:28.834 here on the stage, my movement is relative to the floor. 00:04:29.088 --> 00:04:32.401 The measurement of your car speed is relative to the street, 00:04:33.221 --> 00:04:35.433 actually planes speed measurement 00:04:35.433 --> 00:04:37.648 is made relative to the air, not the floor. 00:04:37.648 --> 00:04:40.349 You might have noticed this while watching a movie. 00:04:40.349 --> 00:04:42.781 A plane speed measurement is relative to the air, 00:04:42.781 --> 00:04:45.579 and the Earth spins around the Sun, etc. 00:04:45.859 --> 00:04:48.206 If you were somewhere in space 00:04:48.206 --> 00:04:51.663 in the middle of nowhere it would be useless 00:04:51.663 --> 00:04:53.914 to ask if you are moving or not 00:04:53.914 --> 00:04:57.681 because there is no reference to compare your position, 00:04:57.681 --> 00:05:00.071 so movement is relative, speeds are relative, 00:05:00.071 --> 00:05:03.163 because they are always measured in relation to something else. 00:05:03.163 --> 00:05:06.461 This was discovered by Galileo 400 years ago. 00:05:06.461 --> 00:05:08.341 That was an interesting fact 00:05:08.341 --> 00:05:10.859 for all physic studies made after Galileo. 00:05:10.859 --> 00:05:14.679 Newton and all great advances of the 18th and 19th centuries 00:05:14.679 --> 00:05:16.626 agreed with Galileo. 00:05:16.626 --> 00:05:19.695 Speed is relative, that's fine, 00:05:19.695 --> 00:05:22.092 speeds aren't absolute. 00:05:22.092 --> 00:05:25.091 But by the end of 19th century something strange happened, 00:05:25.091 --> 00:05:28.323 many physicists studying light 00:05:28.323 --> 00:05:30.738 discovered that light is quite weird, 00:05:30.738 --> 00:05:33.653 light speed is indeed absolute 00:05:33.653 --> 00:05:36.078 and though Galileo stated that speeds were relative, 00:05:36.078 --> 00:05:38.984 that's not the case of light, it's always the same number 00:05:38.984 --> 00:05:40.488 no matter who measures it, 00:05:40.488 --> 00:05:43.477 or how fast is going whoever is measuring, 00:05:43.477 --> 00:05:46.644 no matter how fast the lightbulb sending out the light is moving. 00:05:46.644 --> 00:05:49.080 The measurement always yields the same number 00:05:49.080 --> 00:05:51.115 and this was a problem. 00:05:51.115 --> 00:05:53.221 This might not seem interesting to you 00:05:53.221 --> 00:05:56.556 but physicists of the 19th century were going crazy. 00:05:56.983 --> 00:06:00.577 Problem was: either Galileo was wrong 00:06:00.577 --> 00:06:02.718 and speeds were indeed absolute, 00:06:02.718 --> 00:06:04.583 which was apparently nonsense; 00:06:04.583 --> 00:06:06.877 or those who were measuring light speed 00:06:06.877 --> 00:06:08.896 were wrong and didn't know how to measure. 00:06:08.896 --> 00:06:10.890 But nobody was wrong 00:06:10.890 --> 00:06:13.340 which was even worst. 00:06:13.340 --> 00:06:16.658 Decades went by, 00:06:16.658 --> 00:06:20.151 until in 1905 this guy appeared, 00:06:20.151 --> 00:06:22.028 a man called Albert Einstein, 00:06:22.028 --> 00:06:24.705 who devoted his life to bringing together 00:06:24.705 --> 00:06:27.981 Galileo's idea that speeds were relative 00:06:27.981 --> 00:06:31.215 and the apparently real fact 00:06:31.215 --> 00:06:34.380 shown by the experiments, that there was an absolute speed, 00:06:34.380 --> 00:06:36.011 light speed. 00:06:36.011 --> 00:06:37.822 Long story short, 00:06:37.822 --> 00:06:39.558 because math is complicated, 00:06:39.558 --> 00:06:41.321 part of Einstein genius 00:06:41.321 --> 00:06:43.954 was realizing there was a solution. 00:06:44.641 --> 00:06:47.193 There was a logical solution to the problem 00:06:48.276 --> 00:06:51.292 and that logical solution derived in what we now know 00:06:51.292 --> 00:06:54.388 as Einstein's theory of relativity. 00:06:54.388 --> 00:06:56.787 It's a very interesting theory that changes 00:06:56.787 --> 00:06:59.337 what we understand by space and time, 00:06:59.337 --> 00:07:02.469 for instance, nobody tells us that space is relative 00:07:02.469 --> 00:07:04.809 distances, object lengths 00:07:04.809 --> 00:07:08.200 depend on their movement; if an object moves fast, they shrink. 00:07:08.200 --> 00:07:10.128 Time is also relative, 00:07:10.128 --> 00:07:13.086 any watch ticking relative to my movement, would delay 00:07:13.086 --> 00:07:15.245 this we have measured many times, 00:07:15.245 --> 00:07:19.190 even worst: simultaneity is relative; 00:07:19.190 --> 00:07:21.896 when I say two things happen exactly at once, 00:07:21.896 --> 00:07:24.445 someone moving in relation to me would disagree. 00:07:24.635 --> 00:07:27.834 One of us sees something first and worst: 00:07:27.834 --> 00:07:30.011 we might be moving on opposed directions 00:07:30.011 --> 00:07:31.403 and watch things backwards: 00:07:31.403 --> 00:07:33.097 first this one, then that one. 00:07:33.097 --> 00:07:35.228 So the conclusion is that sometimes, 00:07:35.228 --> 00:07:37.805 the order in time of different things 00:07:37.805 --> 00:07:40.387 is not absolute, the order of time can change, 00:07:40.387 --> 00:07:42.721 one thing before, other thing after 00:07:42.721 --> 00:07:44.780 but this brings up another huge problem, 00:07:44.780 --> 00:07:48.235 if time order is not well defined, what about causality? 00:07:48.235 --> 00:07:50.352 If something causes something else 00:07:50.352 --> 00:07:52.312 that something should had happened first, 00:07:52.312 --> 00:07:54.977 but if we disagree on what happened first, 00:07:54.977 --> 00:07:57.695 where does that leaves causality? 00:07:57.695 --> 00:07:59.600 Another crisis. 00:07:59.600 --> 00:08:01.643 Part of what Einstein did 00:08:01.643 --> 00:08:03.714 was realizing that there was solution, 00:08:03.714 --> 00:08:06.512 a solution to protect causality 00:08:06.512 --> 00:08:09.545 was thinking that light speed is not absolute, 00:08:10.378 --> 00:08:14.915 but the maximum speed of universe. 00:08:14.915 --> 00:08:18.373 If nothing can travel faster than light we protect causality. 00:08:18.663 --> 00:08:21.186 If something could travel faster than light 00:08:21.186 --> 00:08:24.340 then we could travel to the past, 00:08:24.340 --> 00:08:28.142 we would be able to see the effect before the cause, 00:08:28.142 --> 00:08:30.163 which is not the proper way. 00:08:30.163 --> 00:08:32.744 So light speed is the maximum speed 00:08:32.744 --> 00:08:35.001 and that is to protect causality. 00:08:35.302 --> 00:08:38.793 So far as of the beginning of the 20th century, 00:08:38.793 --> 00:08:40.467 light speed was the fastest 00:08:40.467 --> 00:08:43.207 and if that was all left to say, my talk would be done 00:08:43.207 --> 00:08:44.910 and off we go. 00:08:44.910 --> 00:08:47.100 But, fortunately that's not the case. 00:08:47.100 --> 00:08:50.028 In 1916, Einstein developed a second theory, 00:08:50.028 --> 00:08:52.904 also called relativity and that's why people get confused 00:08:52.904 --> 00:08:55.208 this one is called general relativity, 00:08:55.208 --> 00:08:57.031 and it's a theory about gravity. 00:08:57.031 --> 00:08:59.228 Einstein tried to understand gravity, 00:08:59.228 --> 00:09:01.469 which we already understood a bit since Newton; 00:09:01.469 --> 00:09:03.125 but he noticed some problems, 00:09:03.125 --> 00:09:06.579 gravity was thought of by Newton as instantaneous, 00:09:06.579 --> 00:09:09.930 if someone moved the Sun, Earth would immediately react, 00:09:09.930 --> 00:09:14.271 this would go against the fact that nothing can travel faster than light, 00:09:14.271 --> 00:09:17.649 so Einstein began to develop a new gravity theory, 00:09:17.649 --> 00:09:18.919 it took him 10 years, 00:09:18.919 --> 00:09:22.522 an amazing achievement for someone as smart of Einstein, 00:09:22.522 --> 00:09:24.046 was based on a beautiful thing: 00:09:24.046 --> 00:09:27.054 the Equivalence Principle, also discovered by Galileo: 00:09:27.054 --> 00:09:30.142 all objects fall at the same speed 00:09:30.142 --> 00:09:33.330 if two things were dropped at once, they would fall at the same time, 00:09:33.330 --> 00:09:36.628 a bowling ball or a ping pong ball would fall just the same, 00:09:36.628 --> 00:09:39.943 the heavier one does not fall faster, in case you were wondering. 00:09:39.943 --> 00:09:42.056 That means, from another point of view, 00:09:42.353 --> 00:09:47.057 that the trajectory of an object when there is gravity, 00:09:47.057 --> 00:09:48.871 does not depend on the object. 00:09:48.871 --> 00:09:51.294 All objects follow the same trajectory 00:09:51.294 --> 00:09:53.500 curved trajectories, you've seen that, 00:09:53.500 --> 00:09:56.989 I throw objects and they move in parables and ellipses 00:09:56.989 --> 00:10:00.652 but if those trajectories are curve and nondependent of the object 00:10:00.652 --> 00:10:03.826 then trajectory is a property of space, but they are curve, 00:10:03.826 --> 00:10:05.573 then space must be curve. 00:10:05.573 --> 00:10:07.219 Einstein concluded 00:10:07.219 --> 00:10:09.923 that gravity is a space deformation. 00:10:09.923 --> 00:10:11.938 An interesting and beautiful thing, 00:10:11.938 --> 00:10:14.606 and what is beautiful about it is that I can cheat, 00:10:14.886 --> 00:10:17.620 I can use space deformation 00:10:17.620 --> 00:10:19.385 to cheat on Einstein himself, 00:10:19.385 --> 00:10:22.068 so I use Einstein to cheat on Einstein. 00:10:22.068 --> 00:10:25.271 I can imagine ways to distort space 00:10:25.711 --> 00:10:29.317 to work around the statement "nothing can go faster than light" 00:10:29.317 --> 00:10:32.500 and, technically, I could reach a faraway star 00:10:32.500 --> 00:10:34.736 and then come back in time for dinner. 00:10:34.736 --> 00:10:38.452 I will share with you two possibilities, 00:10:38.452 --> 00:10:41.414 that are allowed on Einstein theory, 00:10:41.414 --> 00:10:42.636 one is beautiful 00:10:42.636 --> 00:10:46.328 and its technical name is Einstein-Rosen bridge, 00:10:46.328 --> 00:10:48.726 sounds technical because Einstein 00:10:48.726 --> 00:10:50.795 and another scientist called Rosen 00:10:50.795 --> 00:10:53.887 had this idea in 1935. 00:10:53.887 --> 00:10:57.077 But in literature and on sci-fi movies 00:10:57.077 --> 00:10:58.793 it is called a Wormhole. 00:10:58.793 --> 00:11:02.104 If you like science fiction then you might have seen it recently, 00:11:02.104 --> 00:11:04.371 in the movie Interstellar. 00:11:04.371 --> 00:11:07.952 On the movie, they travel through a wormhole. 00:11:07.952 --> 00:11:09.782 A wormhole is like a tunnel, 00:11:09.782 --> 00:11:13.677 I enter here and I end up in Alpha Centauri, 00:11:13.677 --> 00:11:15.589 but traveling a shorter distance, 00:11:15.589 --> 00:11:17.885 like a shortcut in space. 00:11:17.885 --> 00:11:19.018 These structures -- 00:11:19.018 --> 00:11:22.553 here is a beautiful diagram of a wormhole in two dimensions -- 00:11:22.933 --> 00:11:26.101 are allowed by the Einstein's theory, 00:11:26.101 --> 00:11:28.905 because this theory allows these tunnels, 00:11:28.905 --> 00:11:30.700 one thing is that the theory allows it 00:11:30.700 --> 00:11:33.119 and another is having an idea of how to do that. 00:11:33.119 --> 00:11:36.115 Nobody knows how to make a wormhole, 00:11:36.115 --> 00:11:38.760 but at least theory allows it. 00:11:38.760 --> 00:11:42.017 Another idea, and I'll let you think about it, 00:11:42.017 --> 00:11:45.370 another idea is that it is not necessary to make holes in space, 00:11:45.370 --> 00:11:48.415 an idea that thought by some guy not so long ago, 00:11:48.415 --> 00:11:51.221 in 1994, this guy on the picture, 00:11:52.286 --> 00:11:55.289 and the idea is different; instead of making holes in space 00:11:55.289 --> 00:11:57.341 let's use another property of space. 00:11:57.341 --> 00:12:01.748 Space can bended, twisted and expanded, 00:12:01.748 --> 00:12:05.208 maybe you heard about how universe expands, 00:12:05.208 --> 00:12:07.406 galaxies move away from one another 00:12:07.406 --> 00:12:10.649 not because they are drifting away from a center 00:12:10.649 --> 00:12:12.663 where an explosion occurred, no. 00:12:12.952 --> 00:12:16.100 The way we understand it in physics is that galaxies are still, 00:12:16.100 --> 00:12:20.105 and what is growing bigger is space; space is expanding. 00:12:20.856 --> 00:12:23.484 So I can use this idea in a small scale. 00:12:24.254 --> 00:12:26.784 Imagine I'm standing here and somehow 00:12:26.784 --> 00:12:29.229 I can expand the space behind me. 00:12:29.229 --> 00:12:31.292 I would start to drift away from that wall, 00:12:31.292 --> 00:12:34.190 and if at the same time I shrink the space in front of me 00:12:34.190 --> 00:12:36.494 I would become closer to the wall in front of me. 00:12:36.494 --> 00:12:39.357 If I combine the expansion and contraction, 00:12:39.357 --> 00:12:42.087 I could move from here to that wall without moving, 00:12:42.087 --> 00:12:44.350 because the space made all the moving. 00:12:44.350 --> 00:12:47.973 This is called warp drive or drive through distortion 00:12:48.841 --> 00:12:51.570 and it's another way to travel faster than light, 00:12:51.570 --> 00:12:54.200 actually you could travel as fast as you wish. 00:12:54.200 --> 00:12:57.801 These are two ideas on how we could travel faster than light. 00:12:58.912 --> 00:13:01.333 But there is a price to pay. 00:13:01.333 --> 00:13:04.332 Such is life, whenever you find something cool 00:13:04.332 --> 00:13:05.721 it's too expensive. 00:13:05.721 --> 00:13:08.017 We have a similar case here: 00:13:08.615 --> 00:13:10.951 from those two ideas, 00:13:10.951 --> 00:13:13.554 both worm holes and warp propulsion 00:13:13.554 --> 00:13:16.095 require, whenever we do the math of something 00:13:16.095 --> 00:13:19.264 called negative energy, which might not be crystal clear for you, 00:13:19.264 --> 00:13:21.590 but remember what Einstein said: 00:13:21.590 --> 00:13:24.348 "mass and energy are equivalent", the same thing. 00:13:24.348 --> 00:13:27.354 Remember nuclear reactors and atomic bombs, 00:13:27.354 --> 00:13:29.095 mass and energy are the same. 00:13:29.095 --> 00:13:32.574 So negative energy equals negative mass, 00:13:32.940 --> 00:13:36.798 and I'd never went to buy minus 9 pounds of tortilla. 00:13:38.211 --> 00:13:40.213 There are no negative masses, 00:13:40.213 --> 00:13:42.791 without negative masses there are no negative energies 00:13:42.791 --> 00:13:46.063 and without negative energies none of this is possible, 00:13:46.063 --> 00:13:48.043 No holes in space-time, 00:13:48.043 --> 00:13:50.422 no warp propulsion, 00:13:50.422 --> 00:13:51.589 and that's a problem. 00:13:51.589 --> 00:13:53.846 Negative energy is not forbidden, 00:13:53.846 --> 00:13:56.043 physics laws don't forbid it, 00:13:56.043 --> 00:13:57.743 but we've never seen it. 00:13:57.743 --> 00:14:00.544 It's one of those things that simply do not exist. 00:14:01.449 --> 00:14:04.763 So, with this initial question: 00:14:04.763 --> 00:14:06.705 Can we travel faster than light? 00:14:06.705 --> 00:14:09.830 will we someday travel the stars and get back in time for dinner? 00:14:09.830 --> 00:14:13.131 In 1905 Einstein told us it was not possible, 00:14:13.131 --> 00:14:15.497 that light speed was a limit, 00:14:15.497 --> 00:14:17.798 but sometimes, using Einstein's other theory, 00:14:17.798 --> 00:14:20.890 general relativity, we can cheat and bend the space, 00:14:20.890 --> 00:14:23.154 expand it, compress it, make holes on it, 00:14:23.154 --> 00:14:25.541 and travel faster than light, 00:14:25.541 --> 00:14:27.068 however, the price of it 00:14:27.068 --> 00:14:29.696 is finding energies or negative masses, 00:14:29.696 --> 00:14:31.774 though they might not exist. 00:14:31.774 --> 00:14:33.488 So we are a bit stuck, 00:14:33.488 --> 00:14:36.882 but such is science and that's part of my message, 00:14:36.882 --> 00:14:39.462 science moves forward by making questions, 00:14:39.462 --> 00:14:41.864 and sometimes we find answers, 00:14:41.864 --> 00:14:44.690 sometimes we find answers we don't like, 00:14:44.690 --> 00:14:48.083 that aren't what we wanted, but universe is not how we want it. 00:14:48.089 --> 00:14:50.149 It is what it is and we sometimes find out 00:14:50.149 --> 00:14:53.092 that we don't have enough information, 00:14:53.092 --> 00:14:55.046 to answer the question, 00:14:55.046 --> 00:14:57.131 and that is our current situation. 00:14:57.131 --> 00:14:59.443 Currently, we do not have all the information. 00:14:59.443 --> 00:15:02.533 Luckily, in 20, 30 or 100 years someone will come 00:15:02.533 --> 00:15:05.570 and find the answer and tell us for once 00:15:05.570 --> 00:15:09.179 if we can reach the stars faster than light speed. 00:15:09.179 --> 00:15:12.016 Before I go I will ask you to do something, 00:15:12.016 --> 00:15:15.840 tonight, if clouds allow it, please go out 00:15:15.840 --> 00:15:17.889 and take a look of the stars 00:15:17.889 --> 00:15:19.831 and think, what is out there? 00:15:19.831 --> 00:15:20.934 Thank you so much. 00:15:20.934 --> 00:15:23.063 (Applause)