字幕列表 影片播放 列印英文字幕 The Force is what gives a Jedi his power. It's an energy field created by all living things. It surrounds us and penetrates us. It binds the galaxy together. So, that's a fairly deep quote, isn't it? Fairly deep quote. And so, I got contacted by a journalist for The Guardian. They were doing an article on The Force and they wanted to know, from a physicist, well, what were your thoughts on The Force? The Force, of course, is taken -- and George Lucas himself has admitted this -- that it was informed by, sort of, concepts of Eastern mysticism and tying together the world, the universe, in terms of almost like a spiritual force that binds us, binds us all together. But it also obeys your commands. Now, I have a lot of problems, when it comes to quantum mechanics, for example, where quantum mechanics is abused in terms of 'quantum woo' and the idea that quantum mechanics tells us that everything is bound together, and that, um, you know, Brady's electrons and my electrons are all part of one holistic, integrated whole. Kid, I've flown from one side of this galaxy to the other. I've seen a lot of strange stuff; but I've never seen anything to make me believe there's one all-powerful force controlling everything. In this universe, that doesn't happen for reasons I've discussed at length in other videos. But let's think about what -- you know, what -- What could be the origin of The Force in Star Wars? Is there a universe where it might be possible? Let's say my starting point is existing physics, and let's think about how we would have to modify that existing physics to, um, to have something like The Force in the universe around us. What's remarkable in this universe and with current existing physics is that quantum mechanics, at one level, quantum physics *does* tell us that Brady's and my electrons are coupled together. Binds the galaxy together. It *does* tell us that my electrons are coupled with the building over there; are coupled with small, blue, furry creatures on Alpha Centauri; are coupled with the universe at whole. Quantum mechanics does tell us that. And in fact, we can't really think, in some ways -- in terms of the theoretical context -- we can't think of an individual electron; we've got to think of them all coupled together. Its energy surrounds us and binds us. That's called 'entanglement' and, that's, and that sounds very much like The Force. But why doesn't it work in this universe? Well, the reason it doesn't work in [this] universe is that coupling is so *incredibly* tiny; incredibly tiny. You may as well say, if I do this [exhales a puff of breath], that I've affected the orbit of Mars. That's sort of what it's like saying. There is an effect, but that effect is not only *tiny*; it's utterly, completely, totally, fundamentally negligible. It doesn't affect anything in the world around us. [Brady, off camera:] You're almost making the case there, though. You're saying, "For you and me, we can't do it; but maybe a Jedi, [Brady continues] "who is more sensitive or can amplify these things" But what would have to happen -- So, it's interesting because, um, there are people like Deepak Chopra; there are people in *this* universe, in this world who claim that this coupling happens. But the coupling doesn't happen. Quantum mechanics, if -- [Brady, off camera:] But *you* just said the coupling happens. No! The coupling happens *theoretically* and you have to set the *theory* up so that that, um, coupling is within the theory. But there's a big difference between a theory and something that happens practically, or something that's measurable. As I say, the theory tells us there's a coupling; but that coupling is at the level of -- It's just so far off the scale, not only could we not measure it; we couldn't even begin to hope to measure it with *whatever* technology, because it's *completely* overridden by any other effect. It's, as I say, it's like me [exhales a puff of breath] doing that, and expecting that not only have I affected the orbit of Mars, but I've affected the orbit of planets around Alpha Centauri, or whatever. So it's a very theoretical concept, and the problem is -- [Brady:] But you never ____ theoretical; weak. [Brady, off camera:] It does exist; you *did* affect Mars just then; just not very much. Exactly! But, you know, so, in terms of the context of, um, what it means for our everyday lives -- Can we control it? Does it make a difference? So -- What would need to happen to have something like The Force in this universe, in terms of coupling us all together? Well, that f[orce] -- somehow would have to amplify that entanglement. We'd have to somehow, you know, in terms of, um, me being able to connect with Brady from my electrons, to entangle with Brady's, so I could influence his thoughts, for example. How would I influence his thoughts? Well, I'd have to change the biochemistry? And what's the biochemistry about? It's about electrons? So, somehow my electrons would have to couple -- they'd have to become strongly quantum mechanically entangled with Brady's electrons. How would we do that? I don't know. [Brady, off camera:] But I thought you said our electrons *are* entangled already. Our elec -- [Brady, off camera:] And we're close to each other. But that, but that level of entanglement is so absolutely minuscule. [Brady:] Isn't entanglement like pregnant? You can't be weakly pregnant. Absolutely you can be. [Brady:] You're entangled, or you're not entangled. No! No, no, no, no. There's a whole range of different entan -- So, electrons in the same atom can have a strong degree of entanglement; electrons in different objects can have a very, very weak degree of entanglement; electrons on either side of the universe -- that entanglement is so *incredibly* small -- the coupling is so incredibly small that it's just -- I cannot begin to describe just how incr -- [stammers] incredibly and totally minuscule and negligible it is. [Brady, off camera:] Well Professor, if there are degrees of entanglement -- [Brady:] What's the SI unit for entanglement? So an, well, [stammers] You'd have to think of -- the best way of thinking about it is in terms of -- if you've got, ah -- No, it's a very very good question, Brady. Best way of thinking about it is in terms of: What are the energies? Right? So, if you've got, ah, a system at one particular energy -- you've got an object at one particular energy; you've got an object over here at another particular energy. So, is the energy of this object affected by this object, and vice-versa? That's the best way of thinking about it. So, if you bring two atoms together, and what happens is that the electrons will start to interact -- they'll overlap -- and at some point, you no longer think of it as individual atoms; they become a molecule. Alright? So that's a fairly strongly, in terms of the electrons, that's a fairly strongly entangled system. But if you break that out, you don't need to go very, very far at all where this atom just does not feel the influence of this atom at all. And that's over the course of just a few atomic diameters. The bond breaks. So, they're not entangled; they're not communicating with each other. Move this to even a *fraction* of a millimeter, and this atom really does not care about the presence of this atom, in terms of the energies of the electrons in this atom. Move it to the other side of the universe, and that, as I said, that effect is just completely and utterly washed out by us *breathing*, for one thing; by the vibrations, the thermal vibrations of the atoms in the table. So the quantum mechanics that happens down here at the atomic level just doesn't scale up. [Brady, off camera:] It's almost like you're saying, [Brady:] Sure, it's there, but us -- but it's weak and us mortals would never see or measure it. Absolutely. So therefore -- [Brady, off camera:] No, I'm saying, [Brady:] It would take a special kind of person [Brady:] to see it, or control or measure it; [Brady:] and that special person is a Jedi. Maybe. Maybe if -- But they have to, they have to be able to control that entanglement, and amplify that effect. [Brady, off camera:] That's why they're so special. They -- [Professor:] Yeah, and it's a question of how, I guess, with um -- I know this divides the community and I don't want to have hordes of rampaging Star Wars fans chasing after me -- But maybe this midi-chlorian idea? Maybe that somehow amplifies the entanglements? It's an interesting idea. But, the interesting thing here is that within, as I say, within quantum mechanics in this universe, technically -- but I *really* want to stress that -- Technically, um, you have to couple everything together -- you can't just assume: One electron here. You have to consider *all* the electrons in the universe. So, it's interesting. The Force is what gives the Jedi his power. It's an energy field. The Force is what gives a Jedi his power. It's an energy field. Now, already a physicist goes, "Hang on!" Because a force and an energy are *very* different things. [Female voice:] Many Bothans died to bring us this information. [Brady, off camera:] I think you're being a bit -- [Brady:] This is semantics, though, isn't it? [Brady:] The reason I think this is semantics -- [Brady:] 'The Force' with a capital 'F' doesn't have to be a force [Professor:] True, true. That's true. That's true. There is -- I am being, in terms of the pedantry, I guess, it can just be thought of as, as you say, The Force with a capital F rather than a force. But that distinction between force, as a physicist sees it, and energy, is important. But this is the good -- this is the really -- That's a bit of a pedantic one. That is a bit of a pedantic one. But it's interesting -- It says, "It surrounds us and penetrates us." Basically, that's what forces, force fields, or fields, do in the universe. In quantum field theory, we think about the, the field associated with an electron or the field associated with a particle. Which permeates all of space! Or even the electron -- you're used to thinking about the -- or hearing about the Higgs boson and how that field permeates the universe; but that's true of *every* field. It does permeate the entire universe. Those, um, what makes a difference is that if you make a change here, over here, it can only respond at the speed of light; but that field in that sense does permeate the entire universe. So some of this, you know, "It surrounds us and penetrates us." There are fields around us -- force fields -- that indeed surround us and penetrate us. So in that sense, you know, there is some interesting aspects of The Force which connect with us. Nothing more will I teach you today. Clear your mind of questions. Hmmmm. [Brady, off camera:] What does a universe look like where [Brady:] certain people can do it? [Brady:] And does that universe behave differently? Could -- That universe would have to be -- Great, huge questions; and I'm very much thinking on my feet here. I haven't given this a huge amount of thought. So, please feel free to shoot me down completely in the comments. [Brady:] They will. [Professor, laughing:] They will indeed. But, um -- The interesting [thing] about that is, if you are gonna chance a degree of entanglement, it's not just *you* we have to worry about, or the Jedi; it's the environment itself. Because, everything around us in this universe scatters those waves. Scatters those electron waves. And, then you'd have to be able to somehow locally control. What -- so, if the -- my, um -- [if] my wave function is connecting with Brady's wave function, it's not just: I have to connect with Brady; It's that I have to get rid of the influence of this table, which might scatter that wave. So, the universe would have to behave very differently. The energies would have to be different in terms of, um, the -- at the moment, the atoms vibrating in this table are scattering those waves; which means that you don't have these long-range entanglements. You'd have to control *all* the physics. You'd even have to probably think about changing fundamental -- no, you *would*, definitely! -- changing fundamental constants, which means that it wouldn't just be you, Brady, that'd be affected, or me, as a Jedi knight, that'd be affected. The whole universe, the physics would have to be very, very different. And then it might look like a very different place indeed. [Brady, off camera:] There's a long history [Brady continues:] of humans not understanding what was around us, [Brady continues:] gradually understanding what was around us, [Brady continues:] and then being able to harness that to incredible effect, [Brady continues:] good and bad. [Professor:] Yeah. [Brady, off screen:] Atomic bombs are a brilliant example. [Professor:] Yes. [Brady, off screen:] Who's to say that, [Brady continues:] in a galaxy far, far away, [Brady continues:] they haven't found a way to harness and use entanglement to their advantage, [Brady continues:] and you just haven't thought of it yet, [Brady continues:] because you're a silly human? [Professor:] That is -- My problem with that is, is not, as I said, it's not just a question of not being able to design the technology. It's just that the energy scales associated with this -- ____ me, I would love to believe there's a universe out there with The Force. That would be absolutely, absolutely fantastic, that somewhere, you know, there is a universe like the Star Wars universe. Wookies. I'd love to meet a wookie. [Wookie sound] [Brady:] If Luke Skywalker walked into the room right now, [Brady continues:] and used The Force in front of you -- [Brady continues:] he was controlling minds; he was moving things around -- [Brady continues:] Are you saying that quantum entanglement [Brady continues:] would be your first line of inquiry [Brady continues:] to figure out how he was doing it? And there's no visible sort of amplifier for his -- you know, waves associated from -- [Brady, off camera:] He just says, I'm a Jedi. [Brady continues:] I'm a Jedi. I can just do this stuff. [Professor:] Yes. I think I'd probably start thinking about entanglement. Um, the other interesting thing, as well, of course, is the, um, the cognitive abilities, or the pre-cognitive abilities -- The ability to see into the future. [Yoda:] Through The Force, things you will see, other places, the future, the past. Well, it's interesting then, because in this universe, we, you know, there are parallel worlds -- The whole, sort of, elaborate many worlds theory, um, which again, some physicists have a lot of time for, other physicists don't have huge amount of time for. But imagine a universe where somehow, you could communicate with those other worlds, which we can't, at the moment. Could you tap into those other worlds? Could you tap into other possibilities? Because the idea is, in many types of 'many worlds' theories, that every possibility happens. Could you actually couple into those? Could you somehow see into the particular universe you need to see into those particular possibility? [Obi-Wan Kenobi:] Use The Force, Luke. [Professor:] That's, again, a very much fundamental quantum, quantum effect. But let me stress, this is all science fiction. ... or the remaining Type II calculation, because it's really not worth trying to do this calculation terribly carefully. But, basically, it fires for a couple of seconds. So it's, you know, which is accurate enough for these purposes. We need to do the maths now, if you want to actually figure out what the energy is. So, if I have...