The Death Star's OTHER Fatal Flaw

what is the Death Star's other fatal flaw okay so I think we are all now aware that the recently completed Death Star has a tiny tiny flaw and it's just okay okay it's a major flaw I'll acknowledge that but I have some news there's a another major flaw that we have to deal with if we fire our giant super laser everyone in this station is going to turn into paste wait wait we can work out a solution to this with science dang vade dang the star wars super weapons known as Death Star's have been overly analyzed for over 40 years now and in that time fans and even other Star Wars movies have added weaknesses and design flaws to the weapons however there is one particular consequence to firing a planet destroying lazer that I think is often overlooked it has nothing to do with exhaust port scores or rebels but it could be just as disastrous for the empire first how powerful is the Death Star's laser all you have to do is jump to know that it takes some work some force applied over some distance like your legs are doing to move an object with mass away from a source of gravity smart boy Isaac Newton's law of gravitation multiplied by distance describes this amount of work and it says that the further you want to move some object away from a source of gravity the more work the more energy it will take now if you wanted to completely destroy a planet one interpretation of a successful demonstration yeah would be the work you'd have to put into that planet with a laser in order to take out every single bit of its mass so far apart that it wouldn't reform under gravity this is called the planets gravitational binding energy so what we can do now to get that gravitational binding energy is imagine the planet that we want to destroy as an arbitrarily large number of arbitrarily thin shells then if we add up all of the energy that we would need to take each shell out to infinity with some work so that it wouldn't reform under gravity we would get the total amount of energy for a total obliteration if you make a few assumptions about the planet you want to destroy like it's a perfect sphere of uniform density and you go through the full calculus for all these shells you can check out the full derivation in the show notes it's actually not that bad you get this expression which is how much energy you would have to put into a planet to destroy it Death Star style this is unlimited mathematical power if a planet like Alderaan is an earth-sized planet then the gravitational binding energy equation tells us then the amount of energy that this station supe Lisa needs to put out is at least 200 million trillion trillion joules that's as much energy as Earth's Sun puts out over an entire week you may fire when ready yeah but the flaw I was talking about earlier isn't how much energy this station has to produce it's what would happen to every fleshy body on board this station if you released that much energy all at once I mean we can't all be walking tin can light may not have mass but it does have momentum and a super lasers momentum would easily be deadlier than a life smart boy Albert Einstein's equation e equals MC squared is arguably the most famous equation in all of human history and yet I bet most of you haven't seen its final form e equals MC squared only considers objects at rest once those objects start moving their momentum P which is a product of their mass and velocity also starts adding to the total energy and for our purposes here light like laser light doesn't have any mass so we can cross out this part of Einstein's equation what we're left with is energy equaling momentum times the speed of light and because momentum is conserved even something like a massless laser can have recoil I know it may not intuitively feel like it but all lasers have some recoil the reason why we don't feel any recoil from something like a typical laser pointer is because it simply doesn't have that much energy and so it can't put that much force on your body maybe one Pico Newton or one trillionth of a Newton of force if we had real laser rifles they probably wouldn't have much of a kick to them either doing some estimations they might put a force on you that's in the milli Newton range you might not even feel it fire but the Death Star you would definitely feel just from the exponent alone you can see that the Death Star super laser will have an absolutely incredible amount of momentum and like any other firing weapon if it is flinging that moment for words it's going to experience an equal and opposite momentum backwards and it's enough to be the Death Star's other fatal flaw I know I'm getting to it I'm just you're not gonna like it if this station fires everyone on board is going to liquify if we discharge this station's laser depending on our assumptions there are a few sited diameters even though we made it and I'm assuming that this station is a sphere of solid steel it helps make everything easier then we will fire a laser with enough momentum to fling us backwards at anywhere from forty four to a hundred kilometers per second that is literally faster than anything that humans have ever made in that galaxy far far away it takes us about five seconds to discharge the laser right so if we go from zero to two hundred and thirty five thousand miles per hour in five seconds backwards we are gonna pull anywhere between nine hundred and twenty-one hundred G's anyone wearing their seat belts is gonna be torn in half and anyone standing on the decks is gonna hit the wall so hard that they are going to become ketchup fine fine fine you don't believe me you may fire when ready [Music] Wow good thing we had another one of those you could say that it's ironic that if the deaths are fired at Alderaan Alderaan would kind of get its own revenge but there are ways the Empire could engineer around this problem the easiest way to minimize the deadly recoil of the Death Star super laser would be to make the whole station more massive so that the same amount of momentum doesn't affect the station's velocity as much and so Death Star engineers would want to find the densest materials possible to make the station as massive as possible but again there's a problem never mind to keep the acceleration of the station down to a comfortable 1g the station would need to be solid and denser than steel denser than osmium which is the densest substance that we know of as standard temperatures and pressures something denser than the core of our Sun to get the acceleration of the station down to comfortable or almost nothing we don't see it move in the films at all the engineers would have to find a stable material that was as dense as white dwarf stars and as far as we know a stable material like that just does not exist but let's just say that in the Star Wars universe there's some readily available stable hyper dense material that would make the Death Star so massive everyone on board wouldn't turn into goo every time the super laser fired fine oh that could work but it would also give the station a surface gravity of 15 G's according to our assumptions and calculations and that would make me feel as though I weighed a literal ton various sources do say that the Death Star has a large gravitational pull so this kind of value kind of makes sense but it also makes the majority of the station unlivable it's Canon that everyone in the Death Star lives and works on or near the surface but with this kind of gravity only the core within five kilometers of it would have habitable gravity and this is right where the Death Star's laser and power source is supposed to be so this contradicts the core design of the station itself from a certain point of view a certain point of view yes a more sensible option though would be to simply match the thrust from the Death Star's laser with rust from the Death Star's engines but this too would be incredibly dangerous and fuel intensive and we don't see any of the engines firing ever in any of the movies the reason that the possible solutions to deadly Death Star recoil are so intense is that the scale of energy we are talking about here is absolutely enormous one last comparison Ford for context if you put the laser system of the death star inside of Earth and you fired it would move about this fast it's slow sure but the fact that a massless laser could move the entire earth at a speed that you can perceive should most impress you so while we all know that the Death Star has flaws a big one isn't so obvious if a station had a laser powerful enough to destroy whole planets it would also fling itself backwards at a rate that would smoosh safai everyone on board in the process there are ways to engineer around this problem but if one teenager with one proton torpedo and not the best bangs let's admit wasn't obvious to Death Star engineers who knows if they thought is this problem through because science but honestly the Empire sad devotion to this kind of design hasn't helped them defeat the rebels nor has on Oh [Music] this is a weird situation where if we make our calculations even more realistic it's even worse for the Deathstar because if you assume it's not a solid sphere it wouldn't be there'd be people and decks and stuff like that then it's less massive and it would be thrown backwards even faster and no laser can be a hundred percent efficient which means it would have to put out even more energy to get past that efficiency and destroy something with gravitational binding energy so if it's even more realistic it's even worse which leads to even more ketchup people inside of a floating sphere that a teenager destroyed thank you so much for watching Lisa if you like this video on Facebook like it again and if you like this video on YouTube subscribe and hit that notification bell fam as the kids say because we get up to a lot of weird stuff on this channel not just these episodes but also vlogs and live streams and if you go to alpha at project alpha comm you can sign up and get this main show two days earlier than anyone else and get other premium content like natural selection the debate show that I do with Dan Casey which is a lot of fun you won't want to miss it and you can vote if you're on alpha also follow because science on Instagram and Twitter here and also me [Music]

Channel: Because Science

Views: 914,224

Keywords: Nerdist, Fvid, Because Science, Kyle Hill, death star, star wars, planet destroying laser, thrust, momentum, physics, movies

Id: K6-q2edmiGk

Length: 12min 52sec (772 seconds)

Published: Thu Aug 09 2018

Reddit Comments

[u/luciferhelidon]

1. Im surprised kyle didn't talk about heat dissipation given how much he likes to talk about it.
2. Pretty sure the death star is capable of of thrusting itself quite quickly in a direction, even capable of moving in hyperspace. Dunno what its sublight speeds are like though.
3. I believe it uses hypermatter engines so those might negate previous points.

[u/uneducatedshoe2]

Long time viewer, first time commenter. Could the laser be built on some kind of rail system to act as a shock absorber? Like how heavy artillery recoils to reduce some of the force/eject the shell casing. If it was on some kind of railing system, could it also be possible to hook up a generator to where as the laser rockets backwards, it recharges changing the mechanical energy into electrical energy?