ASM047 Ask Science Mike Mini: Lightsabers

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in honor of the release of star wars the force awakens it's ask science mike mini

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so welcome to ask science mike mini a pint-sized version of the show where i answered just one question we're doing this episode to tackle a star wars question in honor of the force awakens and next week i'm going to do several of these episodes for christmas because there's so many great christmas questions in my inbox but enough about that we've got a tiny show to do so let's get it started the darkest side our question for this ask science mike mini comes from steve and he asks via email hey mike if lightsabers actually existed what do you think they'd be made of would they be made of actual light or gamma rays or something else that would give them their properties thanks and may the force be with you well to answer this we have to start by looking at the properties of a lightsaber and then think about plausible ideas in physics that could describe that behavior we're going to come up with a lightsaber hypothesis or at least try to so the first thing i'd notice about lightsabers is they cut through things quickly and easily in the films we see them with no effort whatsoever cutting through organic materials mainly people's arms and legs but also small metal objects cutting the heads off droids that kind of thing and we also see that they have a ton of thermal output because qui-gon in episode one sticks his lightsaber into a very large set of metal blast doors and those doors start to heat up very rapidly and that kind of behavior could be associated with something like a very strong laser or a high amplitude gamma emitter for gamma rays which are a lower frequency version of electromagnetic radiation and we use those in our technology here on earth at this time there are laser cutting torches that are used in industrial applications that can cut through large sheets of metal quickly and easily and so that seems pretty plausible based on that first behavior now there's a couple of problems one it would take a lot of power industrial lasers had to be connected to special power supplies and high voltage and high current power sources so we're having to assume that star wars tech has some sort of unimaginably dense uh energy storage that can fit in the handle or hilt of a lightsaber but there's another problem with lasers being a plausible explanation for lightsabers and to see why just look at a laser pointer if you have a laser pointer and you aim it at something it just goes it's there's no end there's no shape to it and in fact unless you shoot a laser through something cloudy a fog or a mist you can't actually see the laser until it strikes something so that's kind of a problem for lasers as as lightsabers they just follow the inverse square law and and you know slowly get less energy as they get further from the point they were emitted from and that doesn't look like a lightsaber even though high-energy lasers can cut like a lightsaber uh depicted in the film and have a lot of thermal output as we see in the film so we have to strike lasers from the running here as a plausible lightsaber technology now when i look at a lightsaber it looks almost like someone's holding a energized tube of fluorescent light or neon if you actually had a glass full of neon gas and you applied current to it it would look a lot like a lightsaber now it would be in glass so if you struck anything with that glass with shatter and the effect would be ruined even though plasmas are hot enough to be electrically active and to have free electrons they're not terribly dense at some points especially not fluorescent light so they don't actually have that much thermal energy in aggregate the individual atoms and molecules are moving very quickly and have a lot of thermal energy but they're not especially dense now you can have high density plasmas we can see that in the sun or on earth in fusion reactors where we contain plasmas with magnets and then you do have a lot of thermal energy enough to create nuclear fusion in fact and you can use a magnetic fields to contain plasmas now the sun uses gravity because it's massive but you know since plasmas are electrically charged you can use magnets to contain them and in fact we're getting better and better at controlling magnetic fields using computers and creating increasingly sophisticated containers for plasmas using magnets but this would be really challenging from a handheld hilt the little handle of a lightsaber it's probable that something like that's not even possible in physics you could certainly make a plasma charge or plasma field contained in a shape like a lightsaber inside a chamber with a lot of superconducting magnets but i'm not sure it could ever be done from a handheld hilt but that's the least of the problem with a plasma based lightsaber uh here's the really big ones one is heat so enough plasma to have the kind of energy to do what we see in the film would not only emit visible light that would probably be brighter than what we see in the films it would also release a ton of infrared radiation which we call heat and it would burn or maybe even vaporize the hand of its user if it had enough energy to do what we see in the film so now we have to think technologically is there some way that they're not only containing plasma but corralling photons and preventing these infrared light from coming out and heating the air surrounding the lightsaber and i don't have any idea how you would do that in physics today but that's not even the biggest problem with the plasma based lightsaber if you had two lightsabers that somehow worked and solved those problems that contained a field of high energy plasma high density high energy plasma in a space using magnets they would not work like swords if you tried to have a lightsaber battle they would pass right through each other and so i think every lightsaber battle would end with two dead sword wielders a dead sith and a dead jedi because you wouldn't have that ability to strike the other lightsaber um the magnetic fields would just pass right through each other there may be a disruptive capacity some of the plasma could leak and obviously with the kind of energy levels we're talking about that would be catastrophic for all parties involved so here's the bad news in physics as we understand it today i can't actually think of any plausible way to make a lightsaber none you know you can get increasingly elaborate uh with these theories and ideas and you know engineering capacities but at the end of the day as we understand physics there's no way to make a lightsaber and that's not a big deal for star wars because star wars isn't science fiction a lot of people think of star wars as science fiction but a core property of science fiction media and literature is that there is an attempt to explain a plausible mechanism for story elements and things presented so if you think about star trek which is a popular form of science fiction they work hard to explain how teleporters work and how warp drives work and how photon torpedoes work and how phasers work and uh so much so that one of my favorite books as a kid was the star trek technical manual where you had this very large volume that explained the technology behind everything you saw in the enterprise d in star trek the next generation and that's not how the star wars universe works because star wars is fantasy that just happens to be set in space most of the time when you see space in a book or in a film it's associated with science fiction but star wars is a fantasy piece more like lord of the rings where you see fantastic things that are just taken for granted by the characters in the media gandalf makes no explanation to explain the source of his magical powers in the same way that star wars makes no attempt to explain its hyperdrive or its lightsabers [Music]