1 00:00:08,640 --> 00:00:12,600 Speaker 1: Traveling to the stars always seems so exciting in the movies. 2 00:00:12,680 --> 00:00:16,000 Speaker 1: At least it involves lots of dramatic wooshing noises. There's 3 00:00:16,040 --> 00:00:20,440 Speaker 1: some strengths of light, exotic planets to visit, probably dramatic 4 00:00:20,520 --> 00:00:24,400 Speaker 1: meetings with aliens. You also noticed in those movies everybody 5 00:00:24,480 --> 00:00:27,720 Speaker 1: is always well rested. They walk everywhere with a purpose, 6 00:00:28,200 --> 00:00:31,640 Speaker 1: and they're wearing a well fitting uniform, and everybody seems 7 00:00:31,640 --> 00:00:34,280 Speaker 1: to be in great shape. I don't know about you, 8 00:00:34,440 --> 00:00:38,760 Speaker 1: but that's not like any travel experience that I've ever had. Realistically, 9 00:00:38,920 --> 00:00:41,240 Speaker 1: a trip to the stars is more likely to involve 10 00:00:41,360 --> 00:00:44,840 Speaker 1: tired people eating junk food and shopping at duty free stores. 11 00:00:45,400 --> 00:00:48,480 Speaker 1: It probably resembles the experience of a cruise ship more 12 00:00:48,520 --> 00:00:51,760 Speaker 1: than a trip on the Star Trek Enterprise. So load 13 00:00:51,840 --> 00:01:11,520 Speaker 1: up on the buffet because we're going to Alpha Centauri. Hi. 14 00:01:11,800 --> 00:01:15,120 Speaker 1: I'm Daniel. I'm a particle physicist, and you're listening to 15 00:01:15,160 --> 00:01:19,120 Speaker 1: the podcast Daniel and Jorge Explain the Universe, brought to 16 00:01:19,160 --> 00:01:22,319 Speaker 1: you by My Heart Radio. Jorge is still away. He's 17 00:01:22,360 --> 00:01:26,000 Speaker 1: my friend and collaborator and usual co host of this podcast, 18 00:01:26,400 --> 00:01:29,080 Speaker 1: in which we zoom all around the universe and try 19 00:01:29,120 --> 00:01:32,520 Speaker 1: to find interesting, amazing facts and talk to you about 20 00:01:32,560 --> 00:01:35,000 Speaker 1: them and explain them to you so that you really 21 00:01:35,120 --> 00:01:37,920 Speaker 1: understand them, so they're not just words that you hear 22 00:01:37,959 --> 00:01:40,080 Speaker 1: coming out of your mouth to try to impress your friends, 23 00:01:40,240 --> 00:01:43,520 Speaker 1: but actual concepts in your mind you can manipulate and 24 00:01:43,560 --> 00:01:46,440 Speaker 1: talk about with intelligence. And today we're gonna do more 25 00:01:46,440 --> 00:01:48,760 Speaker 1: than just zoom around the universe. We're going to talk 26 00:01:48,800 --> 00:01:51,760 Speaker 1: about how we're going to zoom around the universe. And 27 00:01:51,800 --> 00:01:53,480 Speaker 1: if you're like me, you like looking up at the 28 00:01:53,480 --> 00:01:56,480 Speaker 1: stars and imagining what it's like to be over there. 29 00:01:57,080 --> 00:01:59,240 Speaker 1: What would it be like to orbit that other star? 30 00:01:59,320 --> 00:02:01,440 Speaker 1: Are there planning it over there? Could you put your 31 00:02:01,440 --> 00:02:03,960 Speaker 1: foot on them? And I think there's a natural human 32 00:02:04,000 --> 00:02:07,200 Speaker 1: desire to explore, to see other parts of the world 33 00:02:07,240 --> 00:02:10,840 Speaker 1: and other parts of the universe. Well, the problem is 34 00:02:10,840 --> 00:02:16,840 Speaker 1: that the universe is big, frustratingly big, stubbornly huge. Like 35 00:02:16,919 --> 00:02:20,360 Speaker 1: the nearest star, the closest one to our sun, is 36 00:02:20,480 --> 00:02:24,280 Speaker 1: four point two light years away. It's called Proximus Centauri. 37 00:02:24,840 --> 00:02:28,440 Speaker 1: That's a huge distance by any measure. If you use kilometers, 38 00:02:28,520 --> 00:02:30,400 Speaker 1: which is sort of absurd, you've got a number like 39 00:02:30,600 --> 00:02:35,000 Speaker 1: forty trillion kilometers. It's sort of like we're on a 40 00:02:35,040 --> 00:02:37,799 Speaker 1: little island in the middle of nowhere. If anybody out 41 00:02:37,800 --> 00:02:39,880 Speaker 1: there has been to like Tahiti or a tiny little 42 00:02:39,880 --> 00:02:42,040 Speaker 1: dot in the Pacific Ocean, you know, the feeling of 43 00:02:42,080 --> 00:02:45,200 Speaker 1: standing on an island and being surrounded by water and 44 00:02:45,240 --> 00:02:48,760 Speaker 1: feeling like maybe there's nothing else out there. That's sort 45 00:02:48,760 --> 00:02:51,360 Speaker 1: of the way I feel standing on Earth, where in 46 00:02:51,400 --> 00:02:54,520 Speaker 1: an ocean of space, and everything else out there is 47 00:02:54,680 --> 00:02:58,320 Speaker 1: super duper far away. These distances, they're sort of hard 48 00:02:58,360 --> 00:03:01,040 Speaker 1: to grasp. You know. Let's talk about how long would 49 00:03:01,080 --> 00:03:03,240 Speaker 1: it take to get there. Well, if you travel on 50 00:03:03,320 --> 00:03:05,920 Speaker 1: speeds that are familiar here on Earth, like if you 51 00:03:06,000 --> 00:03:09,000 Speaker 1: traveled at the speed of a car, then going forty 52 00:03:09,080 --> 00:03:13,600 Speaker 1: trillion kilometers would take you about forty five million years. 53 00:03:13,800 --> 00:03:15,560 Speaker 1: Even if you travel at the speed of an airplane, 54 00:03:15,560 --> 00:03:19,080 Speaker 1: it would take you five million years. Now, nobody's actually 55 00:03:19,080 --> 00:03:22,000 Speaker 1: gonna drive to Alpha Centauri or even fly an airplane. 56 00:03:22,240 --> 00:03:25,040 Speaker 1: You can imagine some technology that might take you there 57 00:03:25,080 --> 00:03:28,000 Speaker 1: in a spaceship at a respectable fraction in the speed 58 00:03:28,000 --> 00:03:31,320 Speaker 1: of light, maybe five percent or ten percent. Even those 59 00:03:31,400 --> 00:03:34,119 Speaker 1: kind of ships would take hundreds of years to get 60 00:03:34,160 --> 00:03:36,960 Speaker 1: to Alpha Centauri. And who wants to board a ship 61 00:03:37,000 --> 00:03:39,040 Speaker 1: knowing that they're going to die on it, And who 62 00:03:39,120 --> 00:03:41,760 Speaker 1: wants to have kids on a ship knowing that those 63 00:03:41,840 --> 00:03:45,200 Speaker 1: kids will probably never set foot on land, any land, 64 00:03:45,240 --> 00:03:48,040 Speaker 1: on any planet. This kind of structure, of course, is 65 00:03:48,080 --> 00:03:51,040 Speaker 1: called a colony ship, where you have generations upon generations 66 00:03:51,040 --> 00:03:54,360 Speaker 1: of humanity living on board, and then eventually one day 67 00:03:54,520 --> 00:03:57,720 Speaker 1: some some group of people generations down the road, get 68 00:03:57,760 --> 00:04:00,840 Speaker 1: to actually land on that planet. That would work. That's 69 00:04:00,960 --> 00:04:03,760 Speaker 1: one way to explore the universe. But I want more. 70 00:04:03,920 --> 00:04:06,160 Speaker 1: I'm greedy, and I want to walk on those other 71 00:04:06,200 --> 00:04:09,640 Speaker 1: planets myself. But even if you traveled like at the 72 00:04:09,720 --> 00:04:12,400 Speaker 1: speed of light, it would still take you four years 73 00:04:12,440 --> 00:04:15,560 Speaker 1: to get to proximates centauri. That's a long time to 74 00:04:15,640 --> 00:04:19,440 Speaker 1: spend eating junk food and shopping duty free, And so 75 00:04:19,480 --> 00:04:22,039 Speaker 1: it makes you wonder is there any way to get 76 00:04:22,080 --> 00:04:25,160 Speaker 1: there faster? So today on the podcast, we're asking the 77 00:04:25,279 --> 00:04:35,320 Speaker 1: question can we build a warp drive to travel the universe? 78 00:04:35,600 --> 00:04:37,600 Speaker 1: I want to take a step back and talk about 79 00:04:37,800 --> 00:04:39,960 Speaker 1: how we travel the universe and sort of the size 80 00:04:39,960 --> 00:04:42,880 Speaker 1: of our horizons. You know, a hundred years ago or 81 00:04:42,920 --> 00:04:45,960 Speaker 1: five hundred years ago, things on the other side of 82 00:04:46,040 --> 00:04:50,279 Speaker 1: the Earth seemed unreachable. To travel to China, for example, 83 00:04:50,279 --> 00:04:52,400 Speaker 1: would take months or years. It's not the kind of 84 00:04:52,440 --> 00:04:55,279 Speaker 1: thing you could do in an afternoon or even a week. Now, 85 00:04:55,320 --> 00:04:59,200 Speaker 1: of course, because we have better technology for transportation, it's 86 00:04:59,200 --> 00:05:00,960 Speaker 1: not a big deal to go to the other side 87 00:05:00,960 --> 00:05:02,440 Speaker 1: of the planet. You can go there, you can come 88 00:05:02,480 --> 00:05:05,440 Speaker 1: back a couple of days later. So the scope about 89 00:05:05,480 --> 00:05:08,120 Speaker 1: the universe that we can explore has expanded and has 90 00:05:08,200 --> 00:05:11,920 Speaker 1: expanded because our technology has improved. And so the thing 91 00:05:12,000 --> 00:05:15,719 Speaker 1: to understand is that it's not actually distances that are important. 92 00:05:15,880 --> 00:05:20,200 Speaker 1: The number, the actual number of kilometers between you and 93 00:05:20,200 --> 00:05:23,560 Speaker 1: and another location, isn't the thing that determines whether or 94 00:05:23,560 --> 00:05:27,240 Speaker 1: not it's in sort of your sphere of explorability. What 95 00:05:27,360 --> 00:05:31,520 Speaker 1: determines that is the maximum speed you can travel. Back 96 00:05:31,600 --> 00:05:33,760 Speaker 1: when the fastest thing you can do is ride a horse, 97 00:05:34,080 --> 00:05:37,559 Speaker 1: then going across country was a huge endeavor, not something 98 00:05:37,640 --> 00:05:40,479 Speaker 1: you can do in days of weeks. Going to the 99 00:05:40,480 --> 00:05:42,279 Speaker 1: other side of the planet in less than months or 100 00:05:42,360 --> 00:05:45,760 Speaker 1: years was impossible. Now, of course, the top speed we 101 00:05:45,839 --> 00:05:48,120 Speaker 1: can travel is much much higher. We have airplanes who 102 00:05:48,120 --> 00:05:50,800 Speaker 1: can go hundreds of kilometers per hour, and so our 103 00:05:50,920 --> 00:05:55,120 Speaker 1: sphere of explorability now encompasses essentially the entire Earth, And 104 00:05:55,160 --> 00:05:57,640 Speaker 1: if you talk to old people who remember the day 105 00:05:57,680 --> 00:06:00,640 Speaker 1: when when those kind of technologies weren't wide the available 106 00:06:00,880 --> 00:06:03,760 Speaker 1: to them, the world seems to have suddenly gotten smaller. 107 00:06:04,279 --> 00:06:08,360 Speaker 1: So you might wonder, like, can science just continue? Can 108 00:06:08,400 --> 00:06:11,880 Speaker 1: science deliver and engine that brings the stars into our 109 00:06:11,880 --> 00:06:15,920 Speaker 1: sphere of explorability so that you'll be talking one day 110 00:06:15,960 --> 00:06:19,200 Speaker 1: to your great great grandkids about how amazing it is 111 00:06:19,240 --> 00:06:21,720 Speaker 1: that you can go to Alpha Centauri and and come 112 00:06:21,760 --> 00:06:25,160 Speaker 1: back in the same afternoon. That's the question we're focusing 113 00:06:25,160 --> 00:06:28,200 Speaker 1: on today. Is it possible for science to bring those 114 00:06:28,240 --> 00:06:31,600 Speaker 1: stars into our grasp. So before we dig into the question, 115 00:06:31,760 --> 00:06:34,160 Speaker 1: I of course walked around campus that you see Irvine, 116 00:06:34,440 --> 00:06:36,640 Speaker 1: and I asked people if they thought that a warp 117 00:06:36,760 --> 00:06:39,080 Speaker 1: drive is possible. How much faith did they have in 118 00:06:39,120 --> 00:06:42,239 Speaker 1: science or do they think that we have them already. 119 00:06:42,560 --> 00:06:45,599 Speaker 1: Before you hear these answers, think to yourself, do you 120 00:06:45,640 --> 00:06:48,600 Speaker 1: believe a warp drive is possible now or in the future. 121 00:06:49,080 --> 00:06:51,480 Speaker 1: Here's what people that you see Irhune had to say, 122 00:06:51,640 --> 00:06:54,240 Speaker 1: I honestly don't know enough about that to even answer it. 123 00:06:54,320 --> 00:06:58,400 Speaker 1: I don't know what a warp drive is yes, you 124 00:06:58,480 --> 00:07:02,320 Speaker 1: think like possible in the few you're possible today, uh future, 125 00:07:02,960 --> 00:07:07,960 Speaker 1: you know, I think so. I remember seeing a guide 126 00:07:08,000 --> 00:07:11,240 Speaker 1: that proved that it was possible, but you would have 127 00:07:11,400 --> 00:07:14,080 Speaker 1: to use a lot of energy, and it was changing 128 00:07:14,160 --> 00:07:21,320 Speaker 1: to spacetime ahead and afterwards maybe like today or in 129 00:07:21,320 --> 00:07:25,520 Speaker 1: the future or in the future today. Probably not at 130 00:07:25,560 --> 00:07:28,240 Speaker 1: the most point, I think it can well certainly not now. 131 00:07:28,680 --> 00:07:31,200 Speaker 1: So if all the questions I've ever asked people on 132 00:07:31,240 --> 00:07:33,520 Speaker 1: the street, this is the one that maybe got the 133 00:07:33,600 --> 00:07:37,080 Speaker 1: broadest set of responses. You have people saying I don't 134 00:07:37,080 --> 00:07:39,200 Speaker 1: know what a warp drive is. You have people saying 135 00:07:39,480 --> 00:07:41,960 Speaker 1: very confidently, yeah, I'm pretty sure we'll figure it out, 136 00:07:42,200 --> 00:07:45,080 Speaker 1: to people saying I think people could build them today. 137 00:07:45,280 --> 00:07:48,000 Speaker 1: It's crazy. And let me clarify again what I mean 138 00:07:48,080 --> 00:07:50,280 Speaker 1: by a warp drive. I mean an engine that could 139 00:07:50,280 --> 00:07:54,160 Speaker 1: take a spaceship from here to somewhere else faster than 140 00:07:54,240 --> 00:07:56,760 Speaker 1: light could get there. That's the goal. We don't want 141 00:07:56,760 --> 00:07:58,800 Speaker 1: to travel just close to the speed of light, because 142 00:07:58,840 --> 00:08:01,679 Speaker 1: even that would take us years and years to get anywhere. 143 00:08:01,960 --> 00:08:05,480 Speaker 1: The nearest stars for light years away, but other stars, 144 00:08:05,760 --> 00:08:07,600 Speaker 1: many more stars that we would love to visit in 145 00:08:07,640 --> 00:08:10,920 Speaker 1: our galaxy are hundreds or thousands of light years away. 146 00:08:11,160 --> 00:08:14,120 Speaker 1: Remember that our galaxy is a hundred thousand light years 147 00:08:14,160 --> 00:08:18,480 Speaker 1: across and the next galaxy is millions of light years away. 148 00:08:18,600 --> 00:08:20,600 Speaker 1: So if we want to explore the universe, if we 149 00:08:20,680 --> 00:08:23,320 Speaker 1: want to find alien life, if we want to see 150 00:08:23,520 --> 00:08:26,320 Speaker 1: crazy things that would never happen in our neighborhood of 151 00:08:26,320 --> 00:08:29,760 Speaker 1: the universe, after all, that's what's so amazing about traveling, 152 00:08:30,080 --> 00:08:32,840 Speaker 1: then we need to develop some sort of technology that 153 00:08:33,120 --> 00:08:36,520 Speaker 1: lets us get to places faster than lightwood get there. 154 00:08:36,920 --> 00:08:39,479 Speaker 1: And that's the question we're going to dig into today. 155 00:08:39,520 --> 00:08:54,720 Speaker 1: But first, let's take a quick break. We're back and 156 00:08:54,760 --> 00:08:57,160 Speaker 1: we're talking about whether we can build an engine we 157 00:08:57,200 --> 00:08:59,920 Speaker 1: could put in a starship that would take us somewhere 158 00:09:00,160 --> 00:09:03,360 Speaker 1: faster than light would get there. So the naturally, the 159 00:09:03,440 --> 00:09:06,320 Speaker 1: first question you might ask is can we travel faster 160 00:09:06,360 --> 00:09:11,160 Speaker 1: than light? And here physics is pretty specific. Physics says no, 161 00:09:11,880 --> 00:09:15,000 Speaker 1: nothing can move through space faster than light moves through space. 162 00:09:15,400 --> 00:09:18,840 Speaker 1: And there's already a little clue there, there's a little wrinkle, 163 00:09:19,000 --> 00:09:22,080 Speaker 1: a little loophole you might want to try to take 164 00:09:22,120 --> 00:09:25,920 Speaker 1: advantage of. Nothing moves through space faster than light moves 165 00:09:25,920 --> 00:09:28,080 Speaker 1: through that space those of you either who know something 166 00:09:28,080 --> 00:09:31,280 Speaker 1: about physics and particle physics might have heard of Churenkoff light. 167 00:09:31,320 --> 00:09:35,360 Speaker 1: For example, when a muan moves really fast through ice, 168 00:09:35,600 --> 00:09:38,280 Speaker 1: it can emit this special kind of radiation of blue 169 00:09:38,320 --> 00:09:41,240 Speaker 1: glow called turank Off light, and it does that because 170 00:09:41,240 --> 00:09:45,400 Speaker 1: it's moving faster than the light moves through the ice. Right, 171 00:09:45,440 --> 00:09:48,880 Speaker 1: So muans can go through ice faster than light goes 172 00:09:48,960 --> 00:09:52,480 Speaker 1: through ice, and they produced this turank Off radiation sort 173 00:09:52,480 --> 00:09:54,679 Speaker 1: of for the same reason that a plane produces a 174 00:09:54,760 --> 00:09:58,080 Speaker 1: sonic boom. The muans are traveling faster than the light 175 00:09:58,120 --> 00:10:00,599 Speaker 1: they make, and so the light they catch up to 176 00:10:00,640 --> 00:10:03,200 Speaker 1: the light they make and they're adding to it creates 177 00:10:03,200 --> 00:10:06,760 Speaker 1: this wake, right, So it's sort of like alluminal bloom, 178 00:10:06,760 --> 00:10:10,160 Speaker 1: not a sonic boom. But that doesn't mean that you 179 00:10:10,200 --> 00:10:13,800 Speaker 1: could travel through space faster than light can travel through space. 180 00:10:14,400 --> 00:10:17,360 Speaker 1: It just means that in some materials, some particles can 181 00:10:17,400 --> 00:10:21,120 Speaker 1: travel through that material faster than light travels through that material. 182 00:10:21,679 --> 00:10:24,280 Speaker 1: But the speed of light in a vacuum is still 183 00:10:24,360 --> 00:10:28,120 Speaker 1: the absolute top speed anything can move through space. It 184 00:10:28,240 --> 00:10:31,360 Speaker 1: just so happens that ice slows light down more than 185 00:10:31,360 --> 00:10:33,960 Speaker 1: it slows down muance. For example, so you get this 186 00:10:34,000 --> 00:10:37,920 Speaker 1: special little loophole. But loopholes are a key. We want 187 00:10:37,920 --> 00:10:41,319 Speaker 1: to pay very careful attention to exactly what the laws 188 00:10:41,320 --> 00:10:44,120 Speaker 1: of physics say so we can try to exploit them later. 189 00:10:45,000 --> 00:10:47,560 Speaker 1: But back to traveling faster than the speed of light. 190 00:10:48,080 --> 00:10:49,880 Speaker 1: You've probably heard me say it and learned it in 191 00:10:49,920 --> 00:10:52,760 Speaker 1: lots of other places. Is impossible to travel faster than 192 00:10:52,800 --> 00:10:55,200 Speaker 1: the speed of light, and not just because it would 193 00:10:55,240 --> 00:10:57,960 Speaker 1: require you to have infinite mass or anything else, but 194 00:10:58,080 --> 00:11:01,920 Speaker 1: just because the universe does not out according to special relativity. 195 00:11:01,960 --> 00:11:04,559 Speaker 1: There is no way to get faster than the speed 196 00:11:04,559 --> 00:11:07,320 Speaker 1: of light. In fact, you can't even travel at the 197 00:11:07,360 --> 00:11:09,679 Speaker 1: speed of light if you have any mass at all. 198 00:11:10,160 --> 00:11:14,400 Speaker 1: Only massless things like photons and gravitons can travel at 199 00:11:14,440 --> 00:11:16,480 Speaker 1: the speed of light. So unless you have a way 200 00:11:16,480 --> 00:11:19,520 Speaker 1: to transform your spaceship into light and beam it over there, 201 00:11:19,840 --> 00:11:22,880 Speaker 1: you can't even travel at the speed of light. And 202 00:11:22,920 --> 00:11:25,640 Speaker 1: you might ask, okay, but that's the way we think today, 203 00:11:25,720 --> 00:11:29,640 Speaker 1: that's today's physics idea of the way the universe works. 204 00:11:29,720 --> 00:11:32,520 Speaker 1: Isn't it possible that we're wrong? And that's a good point, 205 00:11:32,520 --> 00:11:35,280 Speaker 1: And I'm always saying on this podcast in other places 206 00:11:35,640 --> 00:11:37,640 Speaker 1: that we have so much to learn about the universe 207 00:11:37,679 --> 00:11:40,559 Speaker 1: that we've learned approximately zero percent of the physics of 208 00:11:40,600 --> 00:11:43,199 Speaker 1: the universe. And that might give you hope. It might 209 00:11:43,200 --> 00:11:45,080 Speaker 1: give you the idea that, well, there could be a 210 00:11:45,120 --> 00:11:47,720 Speaker 1: crack in that armor, or maybe later we'll learn that 211 00:11:47,720 --> 00:11:50,880 Speaker 1: that was wrong. And you know, there's always a possibility, 212 00:11:51,040 --> 00:11:54,240 Speaker 1: there's always a chance that future physics will discover that 213 00:11:54,240 --> 00:11:56,679 Speaker 1: that was not correct. But I'd be very surprised if 214 00:11:56,679 --> 00:11:58,520 Speaker 1: that were true. This is the kind of thing that 215 00:11:58,559 --> 00:12:01,800 Speaker 1: we have tested extensive We've come up with all sorts 216 00:12:01,800 --> 00:12:04,640 Speaker 1: of scenarios to try this. We've tested it out the wazoo, 217 00:12:04,720 --> 00:12:07,600 Speaker 1: We've even tested it into the wazoo, And it's the 218 00:12:07,679 --> 00:12:12,120 Speaker 1: cornerstone of modern quantum field theory. The special relativity and 219 00:12:12,160 --> 00:12:15,200 Speaker 1: the Lorenz groups that we used to build quantum field 220 00:12:15,240 --> 00:12:18,839 Speaker 1: theory would be totally broken if special relativity was wrong. 221 00:12:18,880 --> 00:12:22,439 Speaker 1: And this is the basic assumption of special relativity. So 222 00:12:22,480 --> 00:12:25,760 Speaker 1: it's one of the most well tested axioms in all 223 00:12:25,840 --> 00:12:28,880 Speaker 1: of modern physics that nothing can travel faster than the 224 00:12:28,920 --> 00:12:32,200 Speaker 1: speed of light. So I'd be really shocked if that 225 00:12:32,280 --> 00:12:34,280 Speaker 1: was cracked. If we found a way to move through 226 00:12:34,320 --> 00:12:36,920 Speaker 1: space faster than the speed of light. Now, I can't 227 00:12:36,960 --> 00:12:40,160 Speaker 1: rule it out definitively, because who knows what amazing things 228 00:12:40,360 --> 00:12:43,520 Speaker 1: the future physics will discover. Maybe we all live in 229 00:12:43,520 --> 00:12:46,239 Speaker 1: a simulation and there's a way to rewrite the program 230 00:12:46,320 --> 00:12:49,080 Speaker 1: so that things change, or who knows what. I can't 231 00:12:49,120 --> 00:12:50,800 Speaker 1: rule it out forever. But I don't think that that's 232 00:12:50,840 --> 00:12:54,000 Speaker 1: a fruitful path to developing a warp drive. And even 233 00:12:54,000 --> 00:12:56,160 Speaker 1: if you were to find a crack in that armor, 234 00:12:56,440 --> 00:12:59,319 Speaker 1: you'd still have all sorts of practical problems, like accelerating 235 00:12:59,520 --> 00:13:02,079 Speaker 1: to really high speeds. So you want to go a 236 00:13:02,120 --> 00:13:05,640 Speaker 1: million light years somewhere, traveling through space at those high 237 00:13:05,679 --> 00:13:08,679 Speaker 1: speeds is difficult because you have to accelerate to those 238 00:13:08,800 --> 00:13:10,840 Speaker 1: high speeds, which you can take a long long time 239 00:13:10,880 --> 00:13:14,319 Speaker 1: and a huge amount of energy. So theoretically I think 240 00:13:14,320 --> 00:13:17,000 Speaker 1: it's very unlikely, and practically I don't think it's a 241 00:13:17,040 --> 00:13:19,880 Speaker 1: good approach. But I think the lesson to learn from 242 00:13:19,920 --> 00:13:23,079 Speaker 1: that thought experiment is that we should look for loopholes. 243 00:13:23,559 --> 00:13:26,080 Speaker 1: After all, what is our goal is our goal to 244 00:13:26,200 --> 00:13:28,920 Speaker 1: travel faster than light. I don't have an inherent desire 245 00:13:28,960 --> 00:13:31,560 Speaker 1: to move through space faster than the speed of light. 246 00:13:32,000 --> 00:13:34,160 Speaker 1: What I want to do is I want to get 247 00:13:34,200 --> 00:13:37,880 Speaker 1: to some distant star faster than the lightwood get there. 248 00:13:38,040 --> 00:13:40,319 Speaker 1: I want to get to have Proximus Centauri, for example, 249 00:13:40,520 --> 00:13:42,520 Speaker 1: in less than four years. I'd love to do it 250 00:13:42,720 --> 00:13:46,040 Speaker 1: in an afternoon. So my goal is not actually to 251 00:13:46,160 --> 00:13:49,240 Speaker 1: travel through space faster than the speed of light. What 252 00:13:49,360 --> 00:13:51,559 Speaker 1: I want to do is to get there faster than 253 00:13:51,640 --> 00:13:55,360 Speaker 1: lightwood get there. And that sounds like it's basically saying 254 00:13:55,400 --> 00:13:59,480 Speaker 1: the same thing, but there's an important difference because the 255 00:13:59,600 --> 00:14:03,520 Speaker 1: rule the actual limitation according to special relativity, it's not 256 00:14:03,559 --> 00:14:06,199 Speaker 1: about arriving somewhere faster than the speed of light would 257 00:14:06,280 --> 00:14:09,880 Speaker 1: move through that space. It's about moving through space faster 258 00:14:09,960 --> 00:14:13,000 Speaker 1: than the speed of light. There's an opportunity there. Instead 259 00:14:13,040 --> 00:14:16,160 Speaker 1: of just moving through space and accepting that the space 260 00:14:16,200 --> 00:14:19,440 Speaker 1: between here and Proximus Centauri is four million light years, 261 00:14:19,680 --> 00:14:22,440 Speaker 1: what if we could somehow manipulate that space. What if 262 00:14:22,480 --> 00:14:25,840 Speaker 1: we could squeeze that space, or twist it or bend it, 263 00:14:25,920 --> 00:14:28,440 Speaker 1: or do something to it so that we didn't have 264 00:14:28,600 --> 00:14:31,480 Speaker 1: to move through as much space, so we could keep 265 00:14:31,600 --> 00:14:34,240 Speaker 1: under that speed limit but still get there in a 266 00:14:34,280 --> 00:14:37,280 Speaker 1: shorter amount of time. That's the key, and I think 267 00:14:37,320 --> 00:14:40,720 Speaker 1: there's there's some credit we owe here to science fiction 268 00:14:40,760 --> 00:14:44,280 Speaker 1: authors because a lot of these ideas, the possibility of 269 00:14:44,320 --> 00:14:47,560 Speaker 1: getting somewhere faster than life could get there, come originally 270 00:14:47,640 --> 00:14:51,520 Speaker 1: from science fiction. Those people are thinking about the impact 271 00:14:51,560 --> 00:14:54,280 Speaker 1: of new technologies and what the future might look like, 272 00:14:54,680 --> 00:14:57,520 Speaker 1: and so their job is to think most creatively, to 273 00:14:57,680 --> 00:15:01,040 Speaker 1: think how could we change human society or how human 274 00:15:01,080 --> 00:15:04,440 Speaker 1: society changed if we had this new technology. So they're 275 00:15:04,480 --> 00:15:07,400 Speaker 1: unbound by the rules of physics and certainly by the 276 00:15:07,440 --> 00:15:11,960 Speaker 1: practicalities of the engineering, free to think inventively about how 277 00:15:12,000 --> 00:15:15,080 Speaker 1: to change our lives and explore the universe. So kudos 278 00:15:15,080 --> 00:15:17,360 Speaker 1: to them for coming up with the whole concept of 279 00:15:17,400 --> 00:15:19,400 Speaker 1: a warp drive, and of course I love it in 280 00:15:19,440 --> 00:15:22,280 Speaker 1: all of those movies. But the next step, once the 281 00:15:22,280 --> 00:15:25,080 Speaker 1: science fiction authors have come up with the idea is 282 00:15:25,120 --> 00:15:28,400 Speaker 1: for physicists to figure out how to make it possible 283 00:15:28,640 --> 00:15:31,800 Speaker 1: to take an idea from woe that would be super awesome. 284 00:15:31,800 --> 00:15:34,120 Speaker 1: I wish we could do that too, you know, there 285 00:15:34,200 --> 00:15:36,160 Speaker 1: might be a way that we could do it. And 286 00:15:36,200 --> 00:15:39,160 Speaker 1: then figuring out how to sort of avoid the physics 287 00:15:39,160 --> 00:15:42,880 Speaker 1: blockades to work away around the rules of the universe 288 00:15:43,040 --> 00:15:46,080 Speaker 1: that seemed to be preventing that from being possible, and 289 00:15:46,120 --> 00:15:48,240 Speaker 1: once the physicists have figured out how to make it 290 00:15:48,280 --> 00:15:51,200 Speaker 1: sort of theoretically possible, then to hand it off to 291 00:15:51,240 --> 00:15:52,960 Speaker 1: the next people in the chain, which are of course 292 00:15:53,080 --> 00:15:56,040 Speaker 1: the engineers, because they have to actually build it, you know, 293 00:15:56,120 --> 00:15:59,200 Speaker 1: design it and build it and make it practical, build 294 00:15:59,280 --> 00:16:02,840 Speaker 1: something which less than ten quadrillion dollars or let use, 295 00:16:02,920 --> 00:16:05,560 Speaker 1: less than the mass of the universe. So that's the 296 00:16:05,600 --> 00:16:08,320 Speaker 1: sort of progression of how you go from I really 297 00:16:08,320 --> 00:16:11,480 Speaker 1: want this thing to you know, boarding the next flight 298 00:16:11,520 --> 00:16:14,680 Speaker 1: to Alpha Centauri at four o'clock. Start with the science fiction, 299 00:16:14,920 --> 00:16:17,560 Speaker 1: move through the physicists, and get to the engineers. So 300 00:16:17,600 --> 00:16:20,200 Speaker 1: where are we on that step of the process. Clearly 301 00:16:20,280 --> 00:16:22,720 Speaker 1: science fiction authors have thought of the idea of warp drive, 302 00:16:23,080 --> 00:16:25,280 Speaker 1: and now we're in this step where physicists are thinking 303 00:16:25,760 --> 00:16:29,240 Speaker 1: what could we do, what loopholes could we exploit? And so, 304 00:16:29,320 --> 00:16:31,920 Speaker 1: as I mentioned a few moments ago, the idea here 305 00:16:32,120 --> 00:16:35,840 Speaker 1: is not to move through space faster than light can 306 00:16:35,880 --> 00:16:38,800 Speaker 1: move through space, because that's just forbidden, but instead to 307 00:16:38,800 --> 00:16:43,040 Speaker 1: try to manipulate space. And if manipulate space sounds weird 308 00:16:43,080 --> 00:16:45,600 Speaker 1: to you, then get ready for some weirdness, because we're 309 00:16:45,600 --> 00:16:47,600 Speaker 1: gonna do a lot of this on the podcast, where 310 00:16:47,640 --> 00:16:51,240 Speaker 1: we use normal sounding words together in a way that 311 00:16:51,400 --> 00:16:55,200 Speaker 1: might make no sense initially, And that's because we're pushing 312 00:16:55,200 --> 00:16:56,920 Speaker 1: the boundaries of what we can do and what we 313 00:16:56,960 --> 00:17:00,800 Speaker 1: can understand, and doing that requires challenging our assumption. And 314 00:17:00,840 --> 00:17:03,640 Speaker 1: so what does it mean to manipulate space? Well, first 315 00:17:03,720 --> 00:17:07,200 Speaker 1: you have to let go of maybe your initial concept 316 00:17:07,240 --> 00:17:11,600 Speaker 1: of space, space being emptiness, space being nothing. If you 317 00:17:11,800 --> 00:17:14,399 Speaker 1: if I say the words space and you close your eyes, 318 00:17:14,640 --> 00:17:17,720 Speaker 1: do you imagine twinkling stars out there? Sure? But what's 319 00:17:17,760 --> 00:17:20,680 Speaker 1: between us and those stars? Maybe you imagine some sort 320 00:17:20,720 --> 00:17:25,520 Speaker 1: of wire frame grid of emptiness, right, just like the rulers, 321 00:17:25,520 --> 00:17:28,000 Speaker 1: just like the notches on a ruler between here and there. 322 00:17:28,520 --> 00:17:31,640 Speaker 1: And you might think, well, that's just sort of human interpretation, 323 00:17:31,760 --> 00:17:34,640 Speaker 1: is just an overlay we put onto the nothingness that's 324 00:17:34,680 --> 00:17:38,560 Speaker 1: between here and space. But space is not nothingness. And 325 00:17:38,600 --> 00:17:41,199 Speaker 1: I'm not talking about the quantum fields that are inside it, 326 00:17:41,280 --> 00:17:43,440 Speaker 1: or the particles that are zooming around, or the little 327 00:17:43,440 --> 00:17:46,040 Speaker 1: bits of radiation. I'm not making an argument that space 328 00:17:46,119 --> 00:17:49,320 Speaker 1: is never actually empty. I'm saying that space is more 329 00:17:49,359 --> 00:17:52,960 Speaker 1: than just the backdrop. It's not just the stage on 330 00:17:53,080 --> 00:17:57,359 Speaker 1: which the universe plays out. Space itself is dynamical. It 331 00:17:57,440 --> 00:18:02,199 Speaker 1: can do things that nothingness can't, like what well space 332 00:18:02,240 --> 00:18:05,959 Speaker 1: can bend. We've talked on this podcast about what gravity is. 333 00:18:06,359 --> 00:18:10,000 Speaker 1: Newton thought about gravity as a force between two objects, 334 00:18:10,160 --> 00:18:13,359 Speaker 1: pulling them together, but Einstein showed us that it's actually 335 00:18:13,359 --> 00:18:17,320 Speaker 1: more natural to talk about gravity as the bending of 336 00:18:17,520 --> 00:18:21,560 Speaker 1: space when the presence of mass and energy. So, for example, 337 00:18:21,640 --> 00:18:24,280 Speaker 1: you can imagine the Earth moving around the Sun, not 338 00:18:24,480 --> 00:18:27,439 Speaker 1: as the Sun pulling on the Earth using some force, 339 00:18:27,840 --> 00:18:31,080 Speaker 1: but the Sun distorting space so that it's most natural 340 00:18:31,080 --> 00:18:33,520 Speaker 1: for the Earth to move in this orbit, to blend 341 00:18:33,560 --> 00:18:35,639 Speaker 1: its velocity with the bending of space to come up 342 00:18:35,680 --> 00:18:39,399 Speaker 1: with a stable motion. So it's actually quite an old 343 00:18:39,480 --> 00:18:43,359 Speaker 1: idea that you could manipulate space. That space is not nothing, 344 00:18:43,359 --> 00:18:46,320 Speaker 1: that it can bend. This is an idea from Einstein's 345 00:18:46,359 --> 00:18:50,040 Speaker 1: theory of relativity that space can bend. So already that 346 00:18:50,160 --> 00:18:52,879 Speaker 1: breaks the idea that space is nothing, and it opens 347 00:18:52,880 --> 00:18:55,720 Speaker 1: the door to space doing other things right. Space can bend. 348 00:18:56,200 --> 00:19:00,280 Speaker 1: It can also ripple. We've seen gravitational waves when huge 349 00:19:00,280 --> 00:19:03,600 Speaker 1: objects like binary black holes accelerate around each other and 350 00:19:03,640 --> 00:19:06,600 Speaker 1: collapse into a single black hole. Then you get ripples 351 00:19:06,600 --> 00:19:10,400 Speaker 1: in space. What does that mean. It doesn't mean anything 352 00:19:10,680 --> 00:19:14,040 Speaker 1: if space is emptiness. But it means something if space 353 00:19:14,200 --> 00:19:16,640 Speaker 1: is a thing, if it has properties, if it can 354 00:19:16,720 --> 00:19:19,840 Speaker 1: do stuff, if it can be distorted and twisted. So 355 00:19:19,880 --> 00:19:24,280 Speaker 1: we're familiar with space bending due to gravity, were recently 356 00:19:24,440 --> 00:19:27,840 Speaker 1: aware the space can do things like ripple, and space 357 00:19:27,880 --> 00:19:31,600 Speaker 1: can also expand we know from the Big Bang, we 358 00:19:31,640 --> 00:19:34,440 Speaker 1: know from dark energy that space is expanding. Right now. 359 00:19:35,160 --> 00:19:38,600 Speaker 1: Sixty of all the energy in the universe is devoted 360 00:19:38,640 --> 00:19:41,440 Speaker 1: to something we call dark energy, which we don't understand. 361 00:19:41,720 --> 00:19:45,000 Speaker 1: But whatever it is is expanding space all the time. 362 00:19:45,440 --> 00:19:49,400 Speaker 1: It's creating new space between us and other galaxies. Right now, 363 00:19:49,480 --> 00:19:51,840 Speaker 1: it's doing it. It's making a new space between you 364 00:19:51,920 --> 00:19:55,160 Speaker 1: and the person sitting next to you. It's everywhere. So 365 00:19:55,200 --> 00:19:58,679 Speaker 1: space can do all of these things, and the amazing 366 00:19:58,760 --> 00:20:01,560 Speaker 1: thing is that they're no limit to it. As far 367 00:20:01,640 --> 00:20:04,840 Speaker 1: as we know, there's no speed limit to how fast 368 00:20:05,000 --> 00:20:08,720 Speaker 1: you can shrink or expand space. Take for example, the 369 00:20:08,760 --> 00:20:11,520 Speaker 1: Big Bang. What happened in the very first moments of 370 00:20:11,560 --> 00:20:16,320 Speaker 1: the universe. The universe expanded very, very rapidly, much faster 371 00:20:16,680 --> 00:20:19,160 Speaker 1: than the speed of light, much faster than light could 372 00:20:19,240 --> 00:20:22,840 Speaker 1: have moved through that space. That's why, for example, the 373 00:20:22,920 --> 00:20:27,439 Speaker 1: universe now is larger than the speed of light times 374 00:20:27,480 --> 00:20:29,920 Speaker 1: the age in the universe. How is that possible? If 375 00:20:29,920 --> 00:20:32,280 Speaker 1: nothing can travel faster than the speed of light, how 376 00:20:32,320 --> 00:20:36,040 Speaker 1: could stuff get further away from each other than light 377 00:20:36,080 --> 00:20:38,480 Speaker 1: could have traveled through that space. The answer, of course, 378 00:20:38,600 --> 00:20:42,360 Speaker 1: is space expanded. Inflation in the Big Bang is more 379 00:20:42,400 --> 00:20:45,760 Speaker 1: than just stuff moving through space. It's space itself expanding. 380 00:20:46,080 --> 00:20:48,399 Speaker 1: So this is an idea we're familiar with that space 381 00:20:48,440 --> 00:20:52,240 Speaker 1: can expand you might almost say the universe warped. You 382 00:20:52,320 --> 00:20:54,280 Speaker 1: might even think of the Big Bang is a huge 383 00:20:54,560 --> 00:20:58,240 Speaker 1: warping of space, and dark energy now is the continued 384 00:20:58,320 --> 00:21:01,800 Speaker 1: warping of space, all right, So that gives us an opportunity. 385 00:21:02,119 --> 00:21:05,040 Speaker 1: We're talking about how to get somewhere faster than light 386 00:21:05,040 --> 00:21:08,200 Speaker 1: would get us there. And the idea we're working towards 387 00:21:08,520 --> 00:21:10,639 Speaker 1: is not to try to move through space using some 388 00:21:10,760 --> 00:21:14,439 Speaker 1: specially fast Zippi engine, but to change the nature of 389 00:21:14,440 --> 00:21:18,119 Speaker 1: the problem by shrinking the space. And that's the idea 390 00:21:18,200 --> 00:21:21,280 Speaker 1: for a warp drive. That's how we might actually make 391 00:21:21,280 --> 00:21:24,439 Speaker 1: it work. The idea is like this, you want to 392 00:21:24,440 --> 00:21:27,359 Speaker 1: get from here to Alpha Centauri. How do you do 393 00:21:27,400 --> 00:21:29,520 Speaker 1: it well, you don't just move through that space. You 394 00:21:29,600 --> 00:21:33,879 Speaker 1: somehow shrink the space between you and that star. You 395 00:21:34,080 --> 00:21:37,159 Speaker 1: squeeze it, just the way the Sun changes the shape 396 00:21:37,160 --> 00:21:40,040 Speaker 1: the whole nature of space in the Solar System. Use 397 00:21:40,119 --> 00:21:42,480 Speaker 1: some mass and energy, and in a moment we'll talk 398 00:21:42,520 --> 00:21:44,960 Speaker 1: about the details of what we know about how engineers 399 00:21:45,040 --> 00:21:47,960 Speaker 1: might actually make that happen. Use mass and energy in 400 00:21:48,000 --> 00:21:50,320 Speaker 1: some way to squeeze the space so that instead of 401 00:21:50,520 --> 00:21:53,280 Speaker 1: having four point two light years between you and the star, 402 00:21:53,840 --> 00:21:57,880 Speaker 1: you have four point two meters. And similarly, you turn 403 00:21:57,920 --> 00:22:01,080 Speaker 1: around behind you, and instead of having four point two 404 00:22:01,080 --> 00:22:04,400 Speaker 1: meters between you and and where you've left, you can 405 00:22:04,480 --> 00:22:08,040 Speaker 1: expand the space behind you. So the idea for a 406 00:22:08,040 --> 00:22:10,640 Speaker 1: warp drive is something which shrinks the space in front 407 00:22:10,680 --> 00:22:14,440 Speaker 1: of you and expands the space behind you. In that way, 408 00:22:14,440 --> 00:22:17,639 Speaker 1: you're sort of inside a little bubble, and inside that 409 00:22:17,680 --> 00:22:21,320 Speaker 1: bubble you don't even need to move with respect to space. 410 00:22:21,840 --> 00:22:25,800 Speaker 1: It's sort of like instead of running through the airport, 411 00:22:26,080 --> 00:22:29,560 Speaker 1: you stand on a moving walkway and the walkway moves 412 00:22:29,640 --> 00:22:32,360 Speaker 1: for you. That's not perfect analogy, because in that analogy 413 00:22:32,400 --> 00:22:35,200 Speaker 1: the walkway is still moving. And I'll be talking about 414 00:22:35,200 --> 00:22:38,359 Speaker 1: like pulling the terminal closer to you instead of running 415 00:22:38,359 --> 00:22:42,040 Speaker 1: there and stretching the distance behind you. But that's the idea. 416 00:22:42,440 --> 00:22:45,080 Speaker 1: So you'd build the sort of warp drive that shrinks 417 00:22:45,160 --> 00:22:48,480 Speaker 1: the space in front of you, expands the space behind you, 418 00:22:48,880 --> 00:22:50,919 Speaker 1: and then you're in this sort of warp bubble, and 419 00:22:50,960 --> 00:22:54,040 Speaker 1: then you pop out of the bubble right and then 420 00:22:54,119 --> 00:22:57,879 Speaker 1: you're there. And because there's no limit on how fast 421 00:22:57,960 --> 00:23:00,879 Speaker 1: you can expand space or how much con shrink space, 422 00:23:01,440 --> 00:23:04,720 Speaker 1: in theory, there's no limit to how far a warp 423 00:23:04,800 --> 00:23:07,560 Speaker 1: drive could take you, as long as you have the 424 00:23:07,560 --> 00:23:10,359 Speaker 1: ability to do this and the energy budget to get 425 00:23:10,359 --> 00:23:13,600 Speaker 1: it done. So let's talk about how you might actually 426 00:23:13,680 --> 00:23:16,679 Speaker 1: build a warp drive and how much progress science and 427 00:23:16,760 --> 00:23:19,960 Speaker 1: engineers and science fiction authors have made towards making it 428 00:23:20,040 --> 00:23:35,879 Speaker 1: a reality. But first let's take another break. All right, 429 00:23:35,920 --> 00:23:38,399 Speaker 1: So we're talking about warping through the universe, and the 430 00:23:38,520 --> 00:23:42,160 Speaker 1: basic idea is to avoid the limit of the speed 431 00:23:42,200 --> 00:23:44,840 Speaker 1: of light by saying we're not going to move through 432 00:23:44,920 --> 00:23:47,480 Speaker 1: space faster than the speed of light. Instead, we're gonna 433 00:23:47,520 --> 00:23:50,640 Speaker 1: somehow change the shape of space. We're gonna build an engine, 434 00:23:50,720 --> 00:23:54,240 Speaker 1: a warp engine, which changes the nature of the problem 435 00:23:54,280 --> 00:23:56,600 Speaker 1: it doesn't solve the problem directly, it changes it to 436 00:23:56,640 --> 00:24:00,240 Speaker 1: another problem. And you know that's a standard and very 437 00:24:00,240 --> 00:24:03,919 Speaker 1: classic approach, Like it's basically what mathematics is. Somebody asks 438 00:24:03,920 --> 00:24:06,720 Speaker 1: a mathematician, can you solve this problem? They go, no, 439 00:24:06,840 --> 00:24:10,040 Speaker 1: that seems hard, But I can solve this other problem, 440 00:24:10,080 --> 00:24:11,960 Speaker 1: and I can prove that the answer is the same. 441 00:24:12,480 --> 00:24:15,399 Speaker 1: So instead of solving a hard problem, transform it to 442 00:24:15,440 --> 00:24:18,520 Speaker 1: an easy problem and then solve that. So in this case, 443 00:24:18,560 --> 00:24:22,119 Speaker 1: we're taking an impossible problem travel through space faster than 444 00:24:22,160 --> 00:24:26,160 Speaker 1: the speed of light, and transforming it to an easier problem. 445 00:24:26,320 --> 00:24:31,760 Speaker 1: Still really hard, maybe not feasible, but not theoretically impossible 446 00:24:32,000 --> 00:24:35,160 Speaker 1: to get there faster than light would have moved through 447 00:24:35,240 --> 00:24:38,919 Speaker 1: unaltered space. There, the idea again is to change the space, 448 00:24:39,000 --> 00:24:41,320 Speaker 1: is to squeeze the space in front of you and 449 00:24:41,400 --> 00:24:44,560 Speaker 1: expand the space behind you. That's the basic operating principle 450 00:24:44,880 --> 00:24:48,639 Speaker 1: of a warp drive. So let's talk about how that happens, because, 451 00:24:48,960 --> 00:24:52,280 Speaker 1: like I said earlier, squeezing space. Those are two words 452 00:24:52,320 --> 00:24:55,879 Speaker 1: you understand, squeezing and space. But what does it mean 453 00:24:55,920 --> 00:24:59,000 Speaker 1: to squeeze space? How could you possibly do that? What 454 00:24:59,160 --> 00:25:01,880 Speaker 1: kind of thing we you building? Your lab? To make 455 00:25:01,920 --> 00:25:05,040 Speaker 1: that happen. What would a warp drive actually look like? Alright, 456 00:25:05,080 --> 00:25:08,240 Speaker 1: so there's two components there, right, there's squeezing the space 457 00:25:08,240 --> 00:25:10,760 Speaker 1: in front of you and expanding the space behind you. 458 00:25:11,119 --> 00:25:14,159 Speaker 1: Let's do the easy one first. That's squeezing the space 459 00:25:14,200 --> 00:25:17,320 Speaker 1: in front of you. How can you squeeze space? How 460 00:25:17,320 --> 00:25:19,439 Speaker 1: can you make it to the shape of space as 461 00:25:19,480 --> 00:25:23,040 Speaker 1: smaller there's sort of constrained and shrunk a little bit. Well, 462 00:25:23,080 --> 00:25:25,960 Speaker 1: it turns out that's actually not that hard. You're doing 463 00:25:26,000 --> 00:25:29,440 Speaker 1: it right now. Everything with mass is changing the shape 464 00:25:29,440 --> 00:25:33,120 Speaker 1: of space in exactly that way. It's squeezing it, it's constricting, 465 00:25:33,160 --> 00:25:35,639 Speaker 1: it's constraining it. I don't want to get into the 466 00:25:35,720 --> 00:25:39,840 Speaker 1: mathematical details of the metric solutions to Einstein's equations, but 467 00:25:39,920 --> 00:25:42,960 Speaker 1: that's the basic idea. In order to shrink space, all 468 00:25:43,040 --> 00:25:46,439 Speaker 1: you need is a huge amount of mass or energy density, 469 00:25:46,480 --> 00:25:49,560 Speaker 1: because space bends in that exact way that you need 470 00:25:50,000 --> 00:25:53,440 Speaker 1: in the presence of mass and energy. So it basically 471 00:25:53,480 --> 00:25:57,719 Speaker 1: just becomes an engineering problem. You have positive mass and energy, 472 00:25:58,119 --> 00:26:01,240 Speaker 1: you can shrink space. How how much mass and energy 473 00:26:01,280 --> 00:26:04,600 Speaker 1: do you need to shrink space enough to get somewhere 474 00:26:04,640 --> 00:26:07,480 Speaker 1: interesting in the universe. Well, now it's a problem for 475 00:26:07,520 --> 00:26:10,080 Speaker 1: the engineers, and a bunch of folks have thought about this, 476 00:26:10,160 --> 00:26:12,679 Speaker 1: and I've even heard there are people in NASA working 477 00:26:12,720 --> 00:26:15,639 Speaker 1: on it, and they've done some calculations. And as usual, 478 00:26:16,080 --> 00:26:18,960 Speaker 1: when you first start out, you make basic assumptions. You 479 00:26:19,000 --> 00:26:22,120 Speaker 1: try the simplest idea first, and it seems impossible. So 480 00:26:22,160 --> 00:26:25,200 Speaker 1: the first calculation anybody ever did of how much energy 481 00:26:25,240 --> 00:26:28,240 Speaker 1: you would take, how much mass it would take in 482 00:26:28,320 --> 00:26:31,840 Speaker 1: order to bend space to get somewhere, like Proximus Centauri, 483 00:26:32,040 --> 00:26:35,119 Speaker 1: took more mass than all the stuff available in the 484 00:26:35,160 --> 00:26:39,120 Speaker 1: observable universe. That's a hundred billion solar systems for galaxy 485 00:26:39,160 --> 00:26:42,919 Speaker 1: and two trillion galaxies. That's an enormous amount of mass. 486 00:26:43,000 --> 00:26:45,640 Speaker 1: And there's no way you could ever gather that much 487 00:26:45,760 --> 00:26:48,160 Speaker 1: energy and use it for a warp drive. And anyway, 488 00:26:48,160 --> 00:26:50,720 Speaker 1: if you did, you would have already destroyed the universe 489 00:26:51,080 --> 00:26:53,080 Speaker 1: just trying to get somewhere. So it's a bit of 490 00:26:53,119 --> 00:26:55,360 Speaker 1: a chicken and egg problem. But this is the progression 491 00:26:55,400 --> 00:26:58,119 Speaker 1: of engineering, right. First you start out with a simple 492 00:26:58,160 --> 00:27:01,359 Speaker 1: solution that seems impossible and practical, and then somebody figures 493 00:27:01,359 --> 00:27:03,280 Speaker 1: out a way to do it with one percent of 494 00:27:03,280 --> 00:27:06,640 Speaker 1: the energy or costing a hundred times less money. That's 495 00:27:06,640 --> 00:27:10,000 Speaker 1: the way engineering works, and so people have already figured out, 496 00:27:10,040 --> 00:27:11,520 Speaker 1: oh wait, if you do do it this way and 497 00:27:11,520 --> 00:27:14,000 Speaker 1: that way, and you focus that this other direction, then 498 00:27:14,080 --> 00:27:16,440 Speaker 1: you can build a warp drive to get you to 499 00:27:16,480 --> 00:27:19,639 Speaker 1: the next star using only the amount of mass in 500 00:27:19,680 --> 00:27:23,320 Speaker 1: the planet Jupiter. Now, whether that seems like a big 501 00:27:23,400 --> 00:27:26,240 Speaker 1: number to you or not depends on your reference frame 502 00:27:26,680 --> 00:27:29,280 Speaker 1: if you start out comparing it to all the stars 503 00:27:29,280 --> 00:27:32,399 Speaker 1: and Solar system and stuff in the observable universe. Yeah, 504 00:27:32,400 --> 00:27:35,119 Speaker 1: it's a tiny amount of that, but compared to the 505 00:27:35,240 --> 00:27:39,639 Speaker 1: energy that any humans ever harnessed for any purpose, it's huge. 506 00:27:40,040 --> 00:27:43,440 Speaker 1: Remember we're talking about the energy stored in some object 507 00:27:43,480 --> 00:27:46,639 Speaker 1: that has mass. We're talking about releasing all of its energy. 508 00:27:47,080 --> 00:27:50,160 Speaker 1: And there's an enormous amount of energy stored in every 509 00:27:50,160 --> 00:27:53,880 Speaker 1: object that has mass because of E equals mc squared. 510 00:27:54,320 --> 00:27:56,840 Speaker 1: And the reason there's a huge amount of energy and 511 00:27:56,880 --> 00:27:59,880 Speaker 1: every piece of mass is because of the C squared bit, 512 00:28:00,480 --> 00:28:02,760 Speaker 1: see being the speed of light. Speed of light is 513 00:28:02,800 --> 00:28:06,120 Speaker 1: a really big number, and see squared is a really 514 00:28:06,119 --> 00:28:08,840 Speaker 1: big number squared. So you take a small amount of 515 00:28:08,880 --> 00:28:12,359 Speaker 1: mass like a raisin, which weighs maybe one gram. It 516 00:28:12,440 --> 00:28:15,040 Speaker 1: has an incredible amount of energy in it. It has 517 00:28:15,119 --> 00:28:18,960 Speaker 1: as much energy as a nuclear explosion. For example, you 518 00:28:19,000 --> 00:28:21,679 Speaker 1: wanted to build an antimatter weapon, if you had a 519 00:28:21,800 --> 00:28:25,120 Speaker 1: raisin and an anti raisin, that's all you would need 520 00:28:25,160 --> 00:28:27,959 Speaker 1: to have a device with as much explosive power as 521 00:28:28,000 --> 00:28:31,920 Speaker 1: the bombs that were dropped on Hiroshima. So now imagine Jupiter. 522 00:28:32,480 --> 00:28:35,200 Speaker 1: Jupiter is a lot of raisins, there's a huge amount 523 00:28:35,200 --> 00:28:37,760 Speaker 1: of energy, is an incredible amount of energy and jubiter. 524 00:28:37,800 --> 00:28:40,000 Speaker 1: So if somebody tells you I need I have a 525 00:28:40,000 --> 00:28:43,080 Speaker 1: warp drive, but we gotta refuel, and we gotta stop 526 00:28:43,080 --> 00:28:46,320 Speaker 1: by Jupiter and suck it all up, has to transform 527 00:28:46,400 --> 00:28:49,360 Speaker 1: all of Jupiter into energy to build my warp drive, 528 00:28:49,680 --> 00:28:52,200 Speaker 1: you'd probably say, we don't have the budget for that. 529 00:28:52,760 --> 00:28:55,600 Speaker 1: It's a huge reduction. But even requiring all the mass 530 00:28:55,600 --> 00:28:58,840 Speaker 1: of Jupiter to fuel your warp drive is not good enough. 531 00:28:59,400 --> 00:29:01,720 Speaker 1: All right, But recently I read an article that somebody 532 00:29:01,720 --> 00:29:04,120 Speaker 1: came up with a clever reduction in the amount of 533 00:29:04,200 --> 00:29:07,440 Speaker 1: energy required, so that you'd only need something like the 534 00:29:07,560 --> 00:29:10,440 Speaker 1: energy stored in a school bus or a large car. 535 00:29:10,800 --> 00:29:14,040 Speaker 1: And again that's another big step down. From all the 536 00:29:14,080 --> 00:29:16,880 Speaker 1: stuff in the universe down to Jupiter down to the 537 00:29:16,920 --> 00:29:20,240 Speaker 1: stuff in a car. Requires some real cleverness to focus 538 00:29:20,280 --> 00:29:22,160 Speaker 1: that energy in a way that's going to squeeze space 539 00:29:22,520 --> 00:29:25,880 Speaker 1: using only you know, hundreds and hundreds of kilograms of stuff. 540 00:29:25,920 --> 00:29:28,960 Speaker 1: Remember that's still a huge amount of energy compared to 541 00:29:29,000 --> 00:29:33,040 Speaker 1: the explosions of nuclear weapons. It's an enormous budget, but 542 00:29:33,240 --> 00:29:36,680 Speaker 1: it's not totally infeasible. So the engineers have already come 543 00:29:36,760 --> 00:29:39,360 Speaker 1: up with some sort of calculations to make this possible. No, 544 00:29:39,360 --> 00:29:41,840 Speaker 1: nobody's actually built a prototype. This is still just in 545 00:29:41,880 --> 00:29:45,840 Speaker 1: the planning stages that could this ever work stages, But 546 00:29:46,040 --> 00:29:48,760 Speaker 1: you know, the physicists have shown that to get there 547 00:29:48,800 --> 00:29:50,760 Speaker 1: you need to squeeze space, and they've pointed to the 548 00:29:50,760 --> 00:29:54,160 Speaker 1: engineers what we know about squeezing space, which is using 549 00:29:54,240 --> 00:29:57,280 Speaker 1: mass and energy to do things like gravity does. And 550 00:29:57,280 --> 00:29:59,680 Speaker 1: the engineers are working on it, they're chugging through it, 551 00:29:59,720 --> 00:30:02,320 Speaker 1: and there's all the reasons to believe that in a 552 00:30:02,360 --> 00:30:05,560 Speaker 1: few years, five years, ten years, fifty years, somebody might 553 00:30:05,560 --> 00:30:10,640 Speaker 1: be able to build something which begins this process. But 554 00:30:10,640 --> 00:30:13,400 Speaker 1: but to actually have warp drive, you need both sides. 555 00:30:13,800 --> 00:30:16,440 Speaker 1: You need the thing in front of you that squeezes space, 556 00:30:16,680 --> 00:30:20,520 Speaker 1: you also need the thing behind you that expands space. Right, 557 00:30:20,560 --> 00:30:23,000 Speaker 1: you can't have a moving walkway, and the whole walkway 558 00:30:23,040 --> 00:30:25,920 Speaker 1: isn't moving, So let's talk about that. How do you 559 00:30:26,000 --> 00:30:29,680 Speaker 1: expand the space behind you? Well, this is much harder. 560 00:30:30,280 --> 00:30:33,560 Speaker 1: You are not expanding space, right, You have positive mass, 561 00:30:33,600 --> 00:30:36,240 Speaker 1: and so you are shrinking space. You're doing that thing 562 00:30:36,360 --> 00:30:40,640 Speaker 1: that's the space that gravity does. But if shrinking space 563 00:30:40,720 --> 00:30:44,400 Speaker 1: requires having positive mass, you might be tempted to suggest, 564 00:30:44,440 --> 00:30:48,320 Speaker 1: sort of the first dumb idea for how to expand space, 565 00:30:48,640 --> 00:30:52,040 Speaker 1: that maybe you could expand space with negative mass. The 566 00:30:52,120 --> 00:30:55,040 Speaker 1: argument is not very sophisticated. It's really just that it says, 567 00:30:55,840 --> 00:30:57,760 Speaker 1: we don't know how to expand space, but we know 568 00:30:57,800 --> 00:31:01,200 Speaker 1: how to sort of shrink it using positive mass. What 569 00:31:01,280 --> 00:31:04,600 Speaker 1: if we use negative mass to expand it. It's not 570 00:31:04,680 --> 00:31:08,120 Speaker 1: a terrible argument. The problem is, of course, what does 571 00:31:08,200 --> 00:31:11,200 Speaker 1: negative mass mean. It's another of these examples. You take 572 00:31:11,320 --> 00:31:14,520 Speaker 1: two words that makes sense, negative and mass, and you 573 00:31:14,600 --> 00:31:17,160 Speaker 1: put them together and you go, huh, what is that? 574 00:31:17,720 --> 00:31:21,520 Speaker 1: Everything you've ever experienced has positive mass. I have positive 575 00:31:21,520 --> 00:31:26,080 Speaker 1: mass more than i'd like. Raisins of positive mass, hamsters, bananas, everything, 576 00:31:26,120 --> 00:31:29,760 Speaker 1: has positive mass. We've never seen anything with negative mass. 577 00:31:30,000 --> 00:31:33,440 Speaker 1: We talked about on this podcast for wormholes. You might 578 00:31:33,920 --> 00:31:38,440 Speaker 1: need negative mass exotic matter particles to stabilize wormholes, but 579 00:31:38,600 --> 00:31:41,160 Speaker 1: that doesn't mean that they exist. It just means that 580 00:31:41,200 --> 00:31:43,560 Speaker 1: if you write down the equations, that's the kind of 581 00:31:43,640 --> 00:31:46,120 Speaker 1: thing which could accomplish it. The things that are in 582 00:31:46,200 --> 00:31:50,520 Speaker 1: equations aren't necessarily also part of the universe. So we've 583 00:31:50,560 --> 00:31:53,200 Speaker 1: never seen negative mass, and we don't know how to 584 00:31:53,280 --> 00:31:56,320 Speaker 1: make negative mass. And also, even if you could make 585 00:31:56,440 --> 00:31:58,760 Speaker 1: negative mass, could you make a school bus size of 586 00:31:58,800 --> 00:32:02,560 Speaker 1: it a Jupiter, the planet Jupiter size negative mass? That 587 00:32:02,600 --> 00:32:06,000 Speaker 1: seems pretty difficult. It might even be a problem engineers 588 00:32:06,000 --> 00:32:09,440 Speaker 1: couldn't solve. But there is hope. Right, we know that 589 00:32:09,520 --> 00:32:12,040 Speaker 1: this thing can happen. We know that space can expand. 590 00:32:13,080 --> 00:32:16,400 Speaker 1: Decades ago, we might have imagined differently. We might have argued, Look, 591 00:32:16,600 --> 00:32:20,040 Speaker 1: gravity is just an attractive force. All it can do 592 00:32:20,200 --> 00:32:23,680 Speaker 1: is attract stuff. There's no repulsive side of gravity. Gravity 593 00:32:23,720 --> 00:32:26,840 Speaker 1: never pushes things apart the way magnetism can, or the 594 00:32:26,880 --> 00:32:29,120 Speaker 1: strong force can, or even the weak force. All of 595 00:32:29,120 --> 00:32:31,920 Speaker 1: these things can attract and repel because all those things 596 00:32:32,240 --> 00:32:36,720 Speaker 1: have both positive and negative charges. For their force. Gravity 597 00:32:36,840 --> 00:32:39,920 Speaker 1: has only positive charges. This is only positive mass, so 598 00:32:39,960 --> 00:32:44,320 Speaker 1: we can only attract That's what we think. However, we 599 00:32:44,400 --> 00:32:47,560 Speaker 1: also know that we don't really understand gravity, and we 600 00:32:47,640 --> 00:32:51,640 Speaker 1: do know that expansion of space does happen. We don't 601 00:32:51,640 --> 00:32:53,680 Speaker 1: know how to create negative mass. We don't know if 602 00:32:53,760 --> 00:32:56,800 Speaker 1: negative mass is the way to expand space, but we 603 00:32:56,880 --> 00:32:59,080 Speaker 1: do know that space can be expanded because we have 604 00:32:59,200 --> 00:33:02,200 Speaker 1: seen it happen. We believe that the Big Bang is 605 00:33:02,240 --> 00:33:04,760 Speaker 1: a huge expansion of space, though we don't know what 606 00:33:04,920 --> 00:33:08,280 Speaker 1: caused it. We know that dark energy is expanding space, 607 00:33:08,360 --> 00:33:12,120 Speaker 1: but we don't understand the mechanism. So we know it's possible, 608 00:33:12,560 --> 00:33:14,640 Speaker 1: but we don't know how to make it happen. We're 609 00:33:14,880 --> 00:33:17,200 Speaker 1: very far from being able to control it, and we're 610 00:33:17,280 --> 00:33:19,240 Speaker 1: super far from being able to put it in a 611 00:33:19,280 --> 00:33:22,280 Speaker 1: warp drive and take you to Alpha Centauri while you 612 00:33:22,280 --> 00:33:26,080 Speaker 1: stuff your face with junk food. So let's recap. It's 613 00:33:26,120 --> 00:33:30,000 Speaker 1: impossible to travel to Proximus Centauri or Alpha Centauri or 614 00:33:30,120 --> 00:33:34,080 Speaker 1: any of the Centauris by moving through space faster than 615 00:33:34,160 --> 00:33:36,440 Speaker 1: light could do it. You can't build a warp drive 616 00:33:36,480 --> 00:33:38,720 Speaker 1: that just moves through space. I think the kind of 617 00:33:38,720 --> 00:33:41,320 Speaker 1: warp drive to have. For example, in star Trek, does 618 00:33:41,360 --> 00:33:43,800 Speaker 1: that they traveled some factor of the speed of light 619 00:33:43,840 --> 00:33:46,160 Speaker 1: and they can get there more rapidly than light would 620 00:33:46,200 --> 00:33:48,720 Speaker 1: get there. That I'm gonna say it's flat out impossible. 621 00:33:48,720 --> 00:33:52,360 Speaker 1: It is always a possibility that sometimes the future physicists 622 00:33:52,360 --> 00:33:54,960 Speaker 1: will reveal that it wasn't actually impossible all along in 623 00:33:54,960 --> 00:33:57,960 Speaker 1: the some condition we assumed dot dot dot. I think 624 00:33:58,000 --> 00:34:01,360 Speaker 1: that's very unlikely. The more promising way to build a 625 00:34:01,360 --> 00:34:04,320 Speaker 1: warp drive is to change the problem from I'm gonna 626 00:34:04,360 --> 00:34:07,160 Speaker 1: move through space faster than the speed of light too, 627 00:34:07,160 --> 00:34:09,600 Speaker 1: I'm gonna try to squeeze the space. I'm gonna build 628 00:34:09,800 --> 00:34:12,000 Speaker 1: an engine which changes the nature of the problem. It 629 00:34:12,080 --> 00:34:14,759 Speaker 1: squeezes the space in front of me and expands the 630 00:34:14,760 --> 00:34:17,000 Speaker 1: space behind me. Space is not just to ruler you're 631 00:34:17,000 --> 00:34:19,920 Speaker 1: flying by. It's something we're in. It's like we're fish 632 00:34:19,960 --> 00:34:22,160 Speaker 1: and we're swimming in water, and to get to the 633 00:34:22,160 --> 00:34:24,319 Speaker 1: other side of the pond, you want to shrink the 634 00:34:24,320 --> 00:34:26,759 Speaker 1: amount of water that's between you and the other side 635 00:34:26,800 --> 00:34:29,680 Speaker 1: of the pond. So theoretically we think that could work. 636 00:34:30,040 --> 00:34:33,120 Speaker 1: Practically there's some big issues. Shrinking space in front of 637 00:34:33,160 --> 00:34:38,040 Speaker 1: you is very difficult. Maybe impractical, though theoretically we know, 638 00:34:38,200 --> 00:34:40,840 Speaker 1: we think we know what's going on, but expanding the 639 00:34:40,880 --> 00:34:43,920 Speaker 1: space behind you that's much harder. We have no idea 640 00:34:43,960 --> 00:34:46,680 Speaker 1: how to accomplish the expanding of space, but we think 641 00:34:46,719 --> 00:34:51,040 Speaker 1: it's probably possible because we see it happening in the universe. 642 00:34:51,160 --> 00:34:53,920 Speaker 1: We just have no handle on what's doing it or 643 00:34:54,000 --> 00:34:56,560 Speaker 1: how to make it happen in a controlled way where 644 00:34:56,600 --> 00:34:58,640 Speaker 1: you'd want to invite your grandmother on a trip to 645 00:34:58,680 --> 00:35:01,680 Speaker 1: the neighboring star. All right, So that's the explanation of 646 00:35:01,800 --> 00:35:04,719 Speaker 1: where we stand in terms of building warp drives. There's 647 00:35:04,760 --> 00:35:08,880 Speaker 1: lots of other really fascinating issues connected to space propulsion, 648 00:35:08,920 --> 00:35:10,720 Speaker 1: and people have written and asking us to talk about 649 00:35:10,719 --> 00:35:12,960 Speaker 1: e M drives and all sorts of other stuff. We'll 650 00:35:13,000 --> 00:35:15,800 Speaker 1: get to that, but until then, thanks very much for 651 00:35:15,840 --> 00:35:18,640 Speaker 1: all the folks who requested this topic, and thank you 652 00:35:18,640 --> 00:35:21,279 Speaker 1: in advance to anybody who sends in a request for 653 00:35:21,320 --> 00:35:24,560 Speaker 1: a future episode. We love hearing what you'd like to 654 00:35:24,600 --> 00:35:27,560 Speaker 1: hear about. So until Jorge gets back, this is Daniel 655 00:35:27,600 --> 00:35:31,240 Speaker 1: signing off for Daniel and Jorge explain the universe. Thanks 656 00:35:31,239 --> 00:35:41,480 Speaker 1: for tuning in. If you still have a question after 657 00:35:41,520 --> 00:35:44,640 Speaker 1: listening to all these explanations. Please drop us a line. 658 00:35:44,680 --> 00:35:46,839 Speaker 1: We'd love to hear from you. You can find us 659 00:35:46,840 --> 00:35:50,640 Speaker 1: at Facebook, Twitter, and Instagram at Daniel and Jorge That's 660 00:35:50,680 --> 00:35:54,040 Speaker 1: one Word, or email us at Feedback at Daniel and 661 00:35:54,160 --> 00:35:57,600 Speaker 1: Jorge dot com. Thanks for listening, and remember that Daniel 662 00:35:57,640 --> 00:36:00,200 Speaker 1: and Jorge Explain the Universe is a production of I 663 00:36:00,400 --> 00:36:03,799 Speaker 1: Heart Radio. For more podcasts for my heart Radio, visit 664 00:36:03,840 --> 00:36:07,360 Speaker 1: the i Heart Radio, a Apple Podcasts, or wherever you 665 00:36:07,440 --> 00:36:14,320 Speaker 1: listen to your favorite shows. H