WEBVTT - How to Build a Real Lightsaber 0:00:00.200 --> 0:00:02.400 Hey, please take a second and leave us a review 0:00:02.480 --> 0:00:06.279 on Apple Podcasts, Spotify, or wherever you listen to the podcast. 0:00:06.960 --> 0:00:07.480 Thanks a lot. 0:00:09.000 --> 0:00:12.840 Hey, Welcome to Sign Stuff production of iHeartRadio. I'm Hoorge 0:00:13.000 --> 0:00:16.200 Champ and today we're answering the question could we build 0:00:16.360 --> 0:00:21.159 a real lightsaber? A long long time ago in a 0:00:21.200 --> 0:00:24.920 galaxy that's here. Star Wars became one of the most 0:00:24.920 --> 0:00:30.080 popular movie and television franchises ever created, and arguably one 0:00:30.080 --> 0:00:32.960 of the coolest things about it are the glowing sorts 0:00:32.960 --> 0:00:36.599 of light that the characters used to fight with. I mean, 0:00:36.720 --> 0:00:39.640 what self respecting geek hasn't dreamed of holding one in 0:00:39.680 --> 0:00:43.120 their hands? But is it actually possible to build one? 0:00:43.440 --> 0:00:45.760 Do the laws of physics allow it? Or is it 0:00:45.800 --> 0:00:49.640 something that's completely in the realm of fantasy and magic. 0:00:50.080 --> 0:00:52.199 To find out, we're going to talk to several scientists 0:00:52.240 --> 0:00:55.600 who specialize in plasma and laser physics and. 0:00:55.520 --> 0:00:58.520 Who are big Star Wars. 0:00:58.240 --> 0:01:02.840 Nerdsally one of them prefers Star Trek, but I won't 0:01:02.880 --> 0:01:04.760 tell you who it is. You'll have to use the 0:01:04.800 --> 0:01:08.360 force to figure it out. So get ready to go 0:01:08.440 --> 0:01:11.880 to warp speed, because this is the podcast you are 0:01:11.880 --> 0:01:15.840 looking for. As we answer the question possible a real 0:01:15.959 --> 0:01:28.080 lightsaber is hm? I promise it's not a trap. Hey everyone, Okay, 0:01:28.160 --> 0:01:30.880 that was a lot of Star Wars puns, but don't worry. 0:01:31.160 --> 0:01:34.000 There's a lot of real cool signs in this episode. 0:01:34.520 --> 0:01:38.640 We're gonna be talking about plasmas, laser needles, and the 0:01:38.720 --> 0:01:41.720 quantum vacuum energy. All have to figure out if it's 0:01:41.800 --> 0:01:46.319 possible to make a real lightsaber and spoiler alert, the 0:01:46.440 --> 0:01:50.880 answer is actually yes. Okay. My sagat to find the 0:01:50.960 --> 0:01:54.960 answer started as most searches do on the Internet. There 0:01:55.000 --> 0:01:58.560 is a YouTube channel called Hacksmith Industries that claims to 0:01:58.600 --> 0:02:03.120 have built the first ever real lightsaber using plasma technology. 0:02:03.680 --> 0:02:06.400 So to help me figure out what plasma is and 0:02:06.440 --> 0:02:09.480 how this proto lightsaber on the Internet works, I reached 0:02:09.480 --> 0:02:12.919 out to my friends at the Princeton Plasma Physics Laboratory, 0:02:13.200 --> 0:02:16.400 a research facility in New Jersey with over five hundred 0:02:16.440 --> 0:02:19.600 scientists and engineers all working on plasma. 0:02:21.560 --> 0:02:22.160 I'm ANDREWS. 0:02:22.240 --> 0:02:22.560 Ricker. 0:02:22.880 --> 0:02:26.760 I am a PhD plasma physicist who spent my entire 0:02:26.800 --> 0:02:29.600 career at the Princeton Plasma Physics Laboratory, and I just 0:02:30.040 --> 0:02:30.720 love my job. 0:02:31.560 --> 0:02:35.160 Archro Domingas. I am a PFC plasma physicist as well. 0:02:35.480 --> 0:02:38.880 Amazing, And are you fans of Star Wars? Yes? Worse 0:02:39.480 --> 0:02:42.400 of course you're physicist. Of course. 0:02:42.440 --> 0:02:46.280 Wait was ar truly even born when Star Wars came out? 0:02:46.400 --> 0:02:49.520 Not the first one, see see, I was a teenager. 0:02:51.880 --> 0:02:54.720 I have to say I am a fan, but none 0:02:54.760 --> 0:02:56.800 of us are as much fans as my eight year 0:02:56.840 --> 0:02:59.359 old son. He is obsessed with it. 0:02:59.520 --> 0:03:02.239 Wow, you're lucky. I can't get my kids to watch 0:03:02.360 --> 0:03:02.840 any of it. 0:03:03.000 --> 0:03:05.440 Oh, I can't get him not to watch. 0:03:06.200 --> 0:03:09.120 That original trilogy or the second. 0:03:09.160 --> 0:03:11.880 So I am very proud to say that he's watched 0:03:11.919 --> 0:03:15.200 all of them, but always gravitates back to four or five. 0:03:15.240 --> 0:03:18.239 And oh, yeah, I can see why you're proud, Yes, 0:03:18.320 --> 0:03:21.560 third proud. All right, Well, I guess the question is 0:03:21.680 --> 0:03:24.680 what do you think about Lightsabers when you first saw 0:03:24.680 --> 0:03:25.120 that movie? 0:03:25.440 --> 0:03:28.800 So I saw it in the theaters, and I'm vague 0:03:28.880 --> 0:03:33.040 memories of just being blown away by these what looked 0:03:33.080 --> 0:03:35.480 like sword fights with I didn't know what they were 0:03:35.480 --> 0:03:40.080 at this time, lasers, plasmas. This was just way beyond 0:03:40.280 --> 0:03:41.360 my teenage self. 0:03:41.720 --> 0:03:43.880 So I don't think I ever remember a time I 0:03:43.920 --> 0:03:46.680 didn't know about lights So they're just kind of a 0:03:46.760 --> 0:03:49.480 thing that existed and that when I was, you know, 0:03:49.720 --> 0:03:52.240 ten or something, I found out that wasn't real. So 0:03:52.360 --> 0:03:54.280 for me, it's just been like a part of life. 0:03:55.280 --> 0:03:58.360 Okay. So there are a few concepts in physics that 0:03:58.440 --> 0:04:02.040 could potentially be used to make a real lightsaber, and 0:04:02.080 --> 0:04:05.880 one of them is plasma. Plasma is basically the fourth 0:04:06.040 --> 0:04:10.720 state of matter. There's solid, liquid, gas, and then there 0:04:10.800 --> 0:04:13.880 is plasma. If you heat up a solid, it melts 0:04:13.960 --> 0:04:16.599 and becomes a liquid. If you heat up a liquid, 0:04:16.800 --> 0:04:19.680 it evaporates and becomes a gas. And if you heat 0:04:19.720 --> 0:04:22.480 up a gas, the gas gets so hot that the 0:04:22.520 --> 0:04:26.400 electrons and all the gas atoms separate from the nucleus 0:04:26.640 --> 0:04:29.360 and you get a floating soup of electrons and positive 0:04:29.400 --> 0:04:33.080 ions the scientists called a plasma, and it can be 0:04:33.279 --> 0:04:37.800 super hot and it glows kind of like a lightsaber. 0:04:38.400 --> 0:04:42.360 So does the real lightsaber you see on YouTube actually 0:04:42.520 --> 0:04:46.960 use plasma? Well, maybe step me through it. What do 0:04:46.960 --> 0:04:49.840 you think is going on in that YouTube version of 0:04:49.920 --> 0:04:50.560 the lightsaber? 0:04:50.880 --> 0:04:51.560 So, first of. 0:04:51.560 --> 0:04:54.400 All, what they did is beautiful. I mean, what a 0:04:54.560 --> 0:04:59.560 beautiful feat of engineering and electronics. It looks beautiful, it 0:04:59.640 --> 0:05:00.920 acts beutifully. 0:05:01.279 --> 0:05:05.440 Yeah. So it's really very much like a blowtorch in 0:05:05.480 --> 0:05:10.080 which they have a directed jet of propane that has been. 0:05:10.000 --> 0:05:13.080 Lit up, and the length is related to how fast 0:05:13.120 --> 0:05:16.479 it's coming out, and as it comes out, it's cooling down, 0:05:16.920 --> 0:05:19.800 and at some point it cools down to the point 0:05:19.800 --> 0:05:22.800 where it goes out at the tip right it stops combining. 0:05:22.920 --> 0:05:25.400 That's what I think is happening. And I would argue 0:05:25.480 --> 0:05:28.240 that the hottest part is the plasma, but the edges 0:05:28.279 --> 0:05:29.760 are propably just spot gas. 0:05:30.760 --> 0:05:34.000 So the lightsaber they built on YouTube is basically just 0:05:34.160 --> 0:05:38.000 the blowtorch or not that different from a lighter or 0:05:38.040 --> 0:05:40.960 a flame. And I should mention that this video with 0:05:41.000 --> 0:05:45.400 the lightsaber has gotten over forty one million views. As 0:05:45.400 --> 0:05:47.960 they explained in the video, they found a nozzle they 0:05:48.040 --> 0:05:51.600 can blow propane and oxygen in a very steady flow, 0:05:52.040 --> 0:05:55.040 and when you ignite it, it makes very super controlled, 0:05:55.520 --> 0:05:59.720 very lightsabery flame that gets up to according to them, 0:06:00.160 --> 0:06:03.839 four thousand degrees celsius, which is hot enough to basically 0:06:03.880 --> 0:06:07.480 burn most things the flame touches. But is it plasma, 0:06:08.080 --> 0:06:09.359 that's not quite clear. 0:06:10.640 --> 0:06:13.520 That's probably a mixture of some plasma hot gas. 0:06:13.680 --> 0:06:14.560 It's a mix of it. 0:06:14.560 --> 0:06:18.000 It has some plasma in it, which leads to the 0:06:18.080 --> 0:06:21.960 light emitted because plasma has light emissions. But I also 0:06:22.040 --> 0:06:24.839 think part of it is that the black body radiation 0:06:25.000 --> 0:06:28.280 from the little pieces of stuff that burnout. So it's 0:06:28.320 --> 0:06:30.800 a mix of several sources of light. 0:06:31.120 --> 0:06:34.440 Yes, okay, this is interesting because it gets into the 0:06:34.480 --> 0:06:38.840 physics of flames or fire. A flame like from a 0:06:38.920 --> 0:06:42.359 candle or a blowtorch can't have plasma in it, but 0:06:42.800 --> 0:06:47.680 not necessarily. Here's what happens. Fire happens because of combustion, 0:06:48.120 --> 0:06:54.440 which is a chemical reaction. That reaction creates energy, which 0:06:54.560 --> 0:06:58.120 heats up what's left after the reaction, and that glows 0:06:58.360 --> 0:07:01.760 just from being hot, kind of like a traditional light 0:07:01.800 --> 0:07:04.599 bulb or a piece of metal that glows when it's hot. 0:07:04.960 --> 0:07:10.160 It's called black body radiation. So on a flame, that 0:07:10.200 --> 0:07:13.400 could be mostly what you see as the part that glows, 0:07:13.720 --> 0:07:17.320 it's just hot gas or hot bits of what's combusted. 0:07:17.720 --> 0:07:21.680 But on some flames, the center of it could be plasma. 0:07:22.040 --> 0:07:24.800 It could be so hot that the electrons get ripped 0:07:24.800 --> 0:07:28.200 from the atoms and you get a true plasma. So 0:07:28.400 --> 0:07:31.960 in the lightsaber on YouTube, it's basically a blowtorch and 0:07:32.000 --> 0:07:35.440 what you're seeing is probably a combination of a hot 0:07:35.480 --> 0:07:44.360 gas and a plasma, and it's not Medichlorian's right, unfortunately. No, Yes, Okay, 0:07:44.440 --> 0:07:47.440 So now the question is is it a real lightsaber? 0:07:47.880 --> 0:07:51.040 Does a blowtorch with a long and super hot flame 0:07:51.320 --> 0:07:54.000 count as a Star Wars lightsaber? 0:07:55.920 --> 0:07:57.920 But I think it goes back to the question like, 0:07:58.640 --> 0:08:01.840 is a lightsaber by definition? Does it have to be 0:08:01.920 --> 0:08:05.200 a plasma? I don't know what the answer to that is, right, 0:08:05.600 --> 0:08:09.240 Can a lightsaber be a very hot blowtorch? 0:08:09.400 --> 0:08:11.360 Maybe? I think it would. 0:08:11.200 --> 0:08:14.320 Still count as a lightsaber. If somebody comes up to 0:08:14.400 --> 0:08:19.360 me and does a flip and pulls that out and confronts. 0:08:18.800 --> 0:08:22.320 Me, I will run away because that, to me is 0:08:22.360 --> 0:08:24.120 a weapon made out of plasma. 0:08:24.240 --> 0:08:25.960 You'd be like, I got a bad feeling about this. 0:08:26.280 --> 0:08:27.320 Yes, exactly. 0:08:28.920 --> 0:08:32.120 I think the argument is what is a lightsaber? And 0:08:32.160 --> 0:08:36.160 since this was inspired by Star Wars, I think we 0:08:36.320 --> 0:08:39.320 have to take what was in the movie as a 0:08:39.440 --> 0:08:42.400 definition of what a lightsaber is, which means you have 0:08:42.480 --> 0:08:44.800 to be able to fight with it. As they hit. 0:08:45.120 --> 0:08:49.600 It's as if two solid pieces of metal or something 0:08:49.800 --> 0:08:51.840 are up against each other and you have to have 0:08:51.920 --> 0:08:55.440 that battle. Where now is who's that the more arm strength? 0:08:56.320 --> 0:09:00.120 I think that is Andrew's strongest argument is when and 0:09:00.480 --> 0:09:04.240 they have the fight scenes, you can stop a lightsaber 0:09:04.240 --> 0:09:08.360 with another lightsaber. I very much doubt that you can 0:09:08.400 --> 0:09:11.280 stop one of these that they made in twenty twenty 0:09:11.320 --> 0:09:13.720 with another one of these. I think they would just 0:09:13.800 --> 0:09:17.120 go through one another, And that I think is the 0:09:17.200 --> 0:09:19.680 strongest argument against it being a lightsaber. 0:09:21.080 --> 0:09:25.000 Okay, sorry, Hacksmith Industries. The physicists here from the Princeton 0:09:25.080 --> 0:09:28.880 Plasma Physics Laboratory don't think what you've made is quite 0:09:28.920 --> 0:09:31.960 a real lightsaber. If you cross to flames or to 0:09:32.120 --> 0:09:35.240 blow torches, the flames are just gonna go through each other, 0:09:35.800 --> 0:09:38.280 or the flow of the hot gases are gonna mix 0:09:38.400 --> 0:09:41.760 in the form. They're not gonna collide and feel solid 0:09:42.000 --> 0:09:45.840 like in the movies. So now the question is is 0:09:45.880 --> 0:09:49.880 that actually possible? Can you create something with plasma so 0:09:49.960 --> 0:09:52.480 that you get a glowing beam that is hot enough 0:09:52.480 --> 0:09:55.480 to melt things and cut through them and also feel 0:09:55.520 --> 0:09:58.760 solid when two of them hit each other? All right, 0:09:58.800 --> 0:10:00.840 all right, I feel like Andrew, you have a vision 0:10:01.040 --> 0:10:05.360 for making a more workable and real lightsaber from plasma. 0:10:05.400 --> 0:10:06.959 How would that work, Andrew, The. 0:10:06.920 --> 0:10:11.040 Way we do it is with magnets. All right. 0:10:11.040 --> 0:10:13.920 Here, doctor Zuicker has an idea for maybe how to 0:10:13.960 --> 0:10:17.160 make a real plasma lightsaber work, and it has to 0:10:17.200 --> 0:10:19.160 do with how scientists are trying to. 0:10:19.120 --> 0:10:21.120 Make a fusion reactor. 0:10:21.559 --> 0:10:24.400 A future reactor is basically the idea that you could 0:10:24.480 --> 0:10:29.200 create a miniature sun here on Earth. Inside of our Sun, 0:10:29.520 --> 0:10:32.440 there's incredible pressure at the very core of it, and 0:10:32.480 --> 0:10:35.559 there's plasma there, and the combination of those two things 0:10:35.800 --> 0:10:39.920 makes atoms fuse together. Well, here on Earth, scientists are 0:10:39.960 --> 0:10:42.800 working on making a plasma like that, and the way 0:10:42.840 --> 0:10:47.119 they hold that plasma together is using essentially a magnetic 0:10:47.200 --> 0:10:50.480 bottle that holds a blob of plasma together. 0:10:51.960 --> 0:10:56.280 We're trying to eventually make a miniature star like the Sun, 0:10:57.080 --> 0:11:01.600 but we use powerful magnets to keep the plasma where 0:11:01.600 --> 0:11:03.200 we want it to be and get it hotter and 0:11:03.280 --> 0:11:07.680 hotter and hotter. So if a lightsaber were to have 0:11:08.080 --> 0:11:13.000 a confining magnetic field in a tube that would keep 0:11:13.040 --> 0:11:17.000 the plasma inside that tube. Number one, you get the shape, Okay, okay, 0:11:17.120 --> 0:11:21.520 But what's interesting is that if two lightsabers, both with 0:11:21.600 --> 0:11:25.560 the same magnetic field, were to then come together. Just 0:11:25.880 --> 0:11:28.880 like your two magnets that want to repel each other, 0:11:29.720 --> 0:11:34.679 they would collide, they would not pass through each other. 0:11:37.480 --> 0:11:40.400 What doctor Zicker is proposing here is that maybe a 0:11:40.480 --> 0:11:45.080 lightsaber could be essentially a magnetic bottle. The hilt of 0:11:45.120 --> 0:11:48.840 the lightsaber could somehow form a magnetic field that contains 0:11:48.960 --> 0:11:52.280 a blob of plasma in the shape of a long tube, 0:11:52.600 --> 0:11:55.079 and it would be hot enough to glow and cut 0:11:55.160 --> 0:11:58.640 through things. And also when you hit another lightsaber, the 0:11:58.679 --> 0:12:01.880 magnetic fields would repel each other, giving you that feeling 0:12:02.000 --> 0:12:05.480 of hitting something solid. So I feel like you're saying 0:12:05.480 --> 0:12:09.960 that to make a lightsaber, you could somehow create basically 0:12:10.040 --> 0:12:13.480 a magnetic bottle in the shape of a sword. 0:12:14.040 --> 0:12:14.640 Exactly. 0:12:15.080 --> 0:12:16.920 We have so many problems with the. 0:12:19.240 --> 0:12:20.520 Why is that nonsense? 0:12:21.960 --> 0:12:25.120 What Andrew is describing is literally what we call a 0:12:25.160 --> 0:12:29.040 magnetic mirror, which is a cylinder of concentric rings that 0:12:29.120 --> 0:12:32.760 are electromagnets with a very strong one at both ends. 0:12:33.000 --> 0:12:37.240 So you've got to have some floating solid electromagnets all 0:12:37.280 --> 0:12:38.240 around the platform. 0:12:38.480 --> 0:12:40.800 To create those kinds of magnetic fields, you need to 0:12:40.880 --> 0:12:45.120 surround that whole area with magnets, which would defeat the 0:12:45.120 --> 0:12:47.920 purpose of it being like a freestanding lightsaber. 0:12:48.640 --> 0:12:56.079 I mean, my entire thing was based upon magical magnetic fields. 0:12:56.720 --> 0:13:00.720 Okay, we tried, but here's the thing about plot. A 0:13:00.720 --> 0:13:04.880 plasma is basically like a gas. It's not solid, and 0:13:04.920 --> 0:13:07.520 it wants to expand and spread out like a gas. 0:13:08.000 --> 0:13:10.240 And the only way to contain a plasma is but 0:13:10.440 --> 0:13:14.559 either something solid or you have to surround it with magnets, 0:13:14.760 --> 0:13:18.280 which would ruin the idea of a lightsaber. So it 0:13:18.320 --> 0:13:22.479 doesn't seem possible to make a real lightsaber using plasma. 0:13:22.880 --> 0:13:26.640 Does that mean a lightsaber is impossible? Well, it turns 0:13:26.640 --> 0:13:30.000 out there is another physics phenomenon that you could use 0:13:30.160 --> 0:13:33.040 to make a lightsaber, and the next two physicists that 0:13:33.120 --> 0:13:36.960 I talked to think it's totally possible. So when we 0:13:37.000 --> 0:13:39.160 come back, we're going to try to make a lightsaber 0:13:39.480 --> 0:13:55.440 out of lasers. Stay with us, we'll be right back. Hey, 0:13:55.520 --> 0:14:00.320 welcome back. We're talking about whether it's possible to the 0:14:00.320 --> 0:14:03.320 real lightsaber like the ones you see in Star Wars 0:14:03.679 --> 0:14:06.400 and so far we talked about the possibility of making 0:14:06.400 --> 0:14:09.680 one out of plasma, but as two physicists from the 0:14:09.679 --> 0:14:14.440 Princeton Plasma Physics laboratory concluded it doesn't seem possible to 0:14:14.679 --> 0:14:18.480 make one, to which I say, never tell me the odds, kid, 0:14:19.080 --> 0:14:22.280 And so we turn to another possible technology we can 0:14:22.440 --> 0:14:25.760 use to make a saver of light, and this one 0:14:25.800 --> 0:14:32.520 involves using light. In twenty nineteen, two physicists polish the 0:14:32.560 --> 0:14:36.280 paper in the European Journal of Physics titled on the 0:14:36.320 --> 0:14:41.040 physical possibility of Lightsabers, in which they say, we focus 0:14:41.120 --> 0:14:44.560 on one major problem with lightsabers that is commonly involved 0:14:44.680 --> 0:14:48.960 as an argument to dismiss them as unrealistic. Light blades 0:14:49.000 --> 0:14:51.280 are not solid and thus cannot be used in a 0:14:51.400 --> 0:14:55.600 duel as normal swords would. Using techniques coming from ultra 0:14:55.720 --> 0:14:59.600 intense laser science, we show that for high enough laser intensities, 0:15:00.240 --> 0:15:04.520 lightsaber blades can feel solid to each other. Now, when 0:15:04.520 --> 0:15:08.040 I read that, I thought, hello, there, so I reached 0:15:08.080 --> 0:15:12.400 out to doctor Jean Sebastian and doctor Francois Fillon Gardeau, 0:15:12.800 --> 0:15:16.760 the authors of the paper. Well, thank you, doctor Gagnon 0:15:16.840 --> 0:15:19.119 and doctor Philian Gardou for joining. 0:15:18.880 --> 0:15:20.080 Us like here is online. 0:15:20.200 --> 0:15:21.280 It's a pleasure to be here. 0:15:21.600 --> 0:15:25.680 Both Fasy and myself are really really huge Star Wars 0:15:25.720 --> 0:15:29.320 fans born in the seventies. I mean Star Wars shape 0:15:29.320 --> 0:15:32.960 my childhood. Really, I've watched the movie so many times, 0:15:33.000 --> 0:15:35.360 like you then by heart, and I don't know. There's 0:15:35.400 --> 0:15:38.080 something about like the Jedi Knight and the lightsaber that 0:15:38.200 --> 0:15:40.320 is just I don't know, there's something to it, right, 0:15:40.400 --> 0:15:42.600 Just the sound of it makes my hair rise on the. 0:15:45.320 --> 0:15:48.800 Amazing I guess as a physicist, when you see the movies, 0:15:48.920 --> 0:15:50.280 what do you think a lightsaber is? 0:15:50.720 --> 0:15:53.520 Actually it's funny because I think if you ask any 0:15:53.600 --> 0:15:56.680 Star Wars fan, many of them will say that it's 0:15:56.960 --> 0:16:00.000 like a plasma saber. They would say it's made of plasma. 0:16:00.440 --> 0:16:02.640 I don't know what is the origin of the idea, 0:16:02.920 --> 0:16:05.400 the exact origin, but I don't know. I'm a purist. 0:16:06.040 --> 0:16:10.240 I like the original Star Wars trilogy, and you have 0:16:10.360 --> 0:16:16.320 no mention of plasma anywhere there. We're called them lightsabers. 0:16:14.880 --> 0:16:18.280 Right, that's true. They're not called plasma sabs. 0:16:18.360 --> 0:16:21.240 They're not called planas there. They're gonna light sabers, right. 0:16:21.440 --> 0:16:25.840 Stick to that exactly for me. A concentration of light 0:16:26.040 --> 0:16:30.360 energy that's concentrated in some shape that looks like a saber. 0:16:30.560 --> 0:16:32.800 So they need to be made out of light somehow. 0:16:32.720 --> 0:16:35.680 Exactly, and that stopped at some point, it stops like 0:16:35.680 --> 0:16:36.760 the blade is finite. 0:16:37.120 --> 0:16:40.400 Oh okay, all right, Like I said, doctors Gagnon and 0:16:40.440 --> 0:16:43.160 Filian Grudeaux think they found a way to make a 0:16:43.240 --> 0:16:46.720 lightsaber actually out of light. But to do that, the 0:16:46.840 --> 0:16:50.560 design has to overcome two big challenges that people say 0:16:51.000 --> 0:16:56.120 makes it impossible to do that. Okay, Now, Star Wars 0:16:56.160 --> 0:16:57.960 is fiction, we think. 0:17:00.080 --> 0:17:04.320 All of the future. Actually it happened a long time 0:17:04.359 --> 0:17:07.520 ago in the galaxy far far away. It already happened. 0:17:07.520 --> 0:17:10.800 That's right, that's true. Good point, that's right. Well, we 0:17:10.840 --> 0:17:14.320 can only hope. But people say that lightsabers are impossible. 0:17:14.320 --> 0:17:16.959 What do you think people say lightsabers are impossible to 0:17:16.960 --> 0:17:17.720 be made out of light? 0:17:18.000 --> 0:17:18.200 Yeah. 0:17:18.240 --> 0:17:21.199 One of the reasons for one thing is out do 0:17:21.240 --> 0:17:25.040 you stop light after like a meter of propagation? You know, 0:17:25.280 --> 0:17:27.920 when you have a leaser. Think about the leaser pointer 0:17:28.000 --> 0:17:31.240 for example. The laser pointer will go on forever until 0:17:31.280 --> 0:17:34.840 it hits something or it's reflected on something, so light 0:17:34.960 --> 0:17:39.600 naturally does not stop by itself. One thing that it's 0:17:39.600 --> 0:17:41.719 just for a lightsaber that would be hard to do 0:17:41.960 --> 0:17:44.160 or hard to implement physically. 0:17:44.359 --> 0:17:48.160 Okay, So the first challenge in making a lightsaber out 0:17:48.200 --> 0:17:51.560 of light is that light, when it's admitted, tends to 0:17:51.600 --> 0:17:54.800 want to keep going on forever. So how do you 0:17:54.840 --> 0:17:58.280 make a sword out of light that has a finite length? 0:17:59.080 --> 0:18:01.720 And the second problem, it's the same problem we had 0:18:01.880 --> 0:18:05.120 with the plasma lightsaber, which is how do you make 0:18:05.119 --> 0:18:07.320 the lightsaber feel solid? 0:18:10.680 --> 0:18:13.440 You've seen the movies when the two blades clash together, 0:18:13.960 --> 0:18:16.800 they actually feel solid. But of course that's not what 0:18:16.800 --> 0:18:18.879 you would expect from light, right. 0:18:18.880 --> 0:18:21.960 Right, Like if I cross the flashlights. 0:18:21.400 --> 0:18:22.920 You can just do it and you see that they're 0:18:23.000 --> 0:18:24.680 just like whoa go through each other. 0:18:24.800 --> 0:18:30.160 And that's because light doesn't necessarily interact with itself exactly, 0:18:30.240 --> 0:18:31.040 That's exactly it. 0:18:31.119 --> 0:18:33.960 So if you think that light is made of photons, 0:18:34.160 --> 0:18:37.760 let's say, so little particles of light, they are electrically neutral, 0:18:37.840 --> 0:18:40.760 so it means that they don't have any electromagnetic interaction 0:18:40.840 --> 0:18:43.520 between them. They don't interact in any other way in 0:18:43.600 --> 0:18:46.520 terms of like other forces, like nuclear forces for instance. 0:18:46.800 --> 0:18:49.879 So to a photon, another photon is just invisible. 0:18:50.320 --> 0:18:53.560 Yes, in some sense classically clastically, of. 0:18:53.520 --> 0:18:57.960 Course, they have no way that we traditionally understand that 0:18:58.000 --> 0:19:02.080 they can interact with each other exactly. So those are 0:19:02.160 --> 0:19:05.040 the two reasons people say making a lightsaber out of 0:19:05.119 --> 0:19:08.920 light is impossible. One how do you make it finite 0:19:09.080 --> 0:19:12.399 so the light beam doesn't go on forever? And two 0:19:12.800 --> 0:19:16.280 how do you make light feel solid? Well, it turns 0:19:16.280 --> 0:19:18.760 out there is a way to get around both of 0:19:18.800 --> 0:19:22.719 those problems, and no, it does not involve using the force. 0:19:23.320 --> 0:19:25.680 We'll start with making a finite beam of light. 0:19:26.080 --> 0:19:27.360 According to doctors. 0:19:27.040 --> 0:19:29.960 Canon and Fillian Cordeaux, you can do it with something 0:19:30.040 --> 0:19:34.840 called a needle of light. I've definitely done that as 0:19:34.840 --> 0:19:36.919 a kid, Like when you have a flashlight and you 0:19:37.000 --> 0:19:39.440 turn off the lights and you pretend that you're swinging 0:19:39.920 --> 0:19:43.120 a lightsaber around, but you're right that it keeps going 0:19:43.160 --> 0:19:46.399 on forever. Is that something that you think you have 0:19:46.440 --> 0:19:47.280 a solution. 0:19:47.119 --> 0:19:50.440 For, Well, not the direct solution, but if you look 0:19:50.480 --> 0:19:55.280 at the scientific literature and the research done by any physicists, 0:19:55.400 --> 0:19:58.159 it's called a needle of lights and so it's a 0:19:58.320 --> 0:20:02.159 very particular electro magnetic fail configuration. 0:20:02.200 --> 0:20:03.240 They are very hard. 0:20:03.040 --> 0:20:06.600 To do in a laboratory, so you need very special 0:20:06.640 --> 0:20:09.439 mirrors to do them, but they have the property that 0:20:09.760 --> 0:20:13.159 when this light is focused, the energy will be in 0:20:13.200 --> 0:20:14.840 the form of a long cylinder. 0:20:15.680 --> 0:20:21.119 WHOA, I don't think I was expecting this. Is there 0:20:21.119 --> 0:20:24.280 a process in physics that might allow that to concentrate 0:20:24.359 --> 0:20:26.120 light in a short beam like that? 0:20:26.480 --> 0:20:28.560 Yes? 0:20:28.359 --> 0:20:33.399 Yes, yeah, yes, yes, okay. Can you describe this phenomenon? 0:20:33.640 --> 0:20:34.080 What is it? 0:20:34.119 --> 0:20:36.480 How does it work? I imagine like you're sending a 0:20:36.560 --> 0:20:38.879 light beam that would be cylindrical, so it would be 0:20:38.880 --> 0:20:41.800 more like an annular type of beam. It means that 0:20:41.840 --> 0:20:44.640 instead of having like a cylinder that is filled with light, 0:20:44.800 --> 0:20:47.159 you would only have like the outskirt of it, like 0:20:47.240 --> 0:20:47.640 a ring. 0:20:48.000 --> 0:20:50.600 Oh I see, Instead of a solid beam of light, 0:20:50.840 --> 0:20:52.360 you're shooting out a ring of light. 0:20:52.440 --> 0:20:53.320 Yes, exactly. 0:20:53.520 --> 0:20:56.760 Then you send it on. Imagine in the hilt of 0:20:56.800 --> 0:20:59.280 the lightsaber there will be a mirror at the back, 0:20:59.320 --> 0:21:01.800 and then you send towards that mirror, and then when 0:21:01.800 --> 0:21:05.359 it's reflected like at the focus of the mirror, it 0:21:05.400 --> 0:21:08.200 would look like a needle. And it's what I said. 0:21:08.240 --> 0:21:10.040 It's related to the fact that you have like many 0:21:10.080 --> 0:21:14.040 beams of light. When it reflects to the focus, some 0:21:14.119 --> 0:21:16.320 of those beams will kind of interfere with each other. 0:21:16.359 --> 0:21:19.160 It will cancel in many places, but it would add 0:21:19.240 --> 0:21:21.280 up at the focus. 0:21:21.119 --> 0:21:24.040 And so that gives you a little light needle. 0:21:24.200 --> 0:21:25.320 Yep, exactly. 0:21:26.200 --> 0:21:28.720 Okay, the details of this are a little hard to explain, 0:21:29.080 --> 0:21:32.680 but it is something that physicists that specialize in optics 0:21:32.720 --> 0:21:36.160 and lasers have been able to do. By shooting light 0:21:36.200 --> 0:21:39.440 as a ring instead of a solid beam, and bousing 0:21:39.520 --> 0:21:43.119 and off special curved mirrors, you can essentially focus the 0:21:43.200 --> 0:21:47.400 light beam so that it interferes with itself and concentrates 0:21:47.400 --> 0:21:50.639 its energy into a kind of needle or sharp stick 0:21:50.920 --> 0:21:54.480 of light, and that basically looks like a light saver, 0:21:56.040 --> 0:21:59.280 Like the black waves are interfering and they're building up 0:21:59.320 --> 0:22:01.320 in this needle in this length of space. 0:22:01.640 --> 0:22:04.119 Yes, yes, so the energy of the beam would be 0:22:04.119 --> 0:22:06.800 concentrated in that tiny needle. 0:22:06.640 --> 0:22:07.960 And not anywhere else. 0:22:08.240 --> 0:22:10.800 So there would be much more energy conceptor along the 0:22:10.880 --> 0:22:11.960 needle than the rest. 0:22:12.320 --> 0:22:14.800 But the light would keep going after the needle, it 0:22:14.960 --> 0:22:16.000 just wouldn't be focused. 0:22:16.160 --> 0:22:19.360 Yeah, exactly, so it would be diffuse. After the needles 0:22:19.400 --> 0:22:22.920 you want, it will still propagate, but the energy will 0:22:23.119 --> 0:22:26.760 go down drastically, so it would look like a small 0:22:26.800 --> 0:22:27.240 light saber. 0:22:27.400 --> 0:22:29.439 Uh huh. We would see like an actual seat of 0:22:29.480 --> 0:22:31.159 glowing beam like a lightsaber. 0:22:31.560 --> 0:22:32.240