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From A New Hope to Revenge of the Sith to The Last Jedi, we see starships blown up in battles in space. The larger ships, like Star Destroyers and Dreadnoghts, don't just blow up, however. They partially explode and fall. Larger structures, like the Death Star, explode. Smaller ships, like X-Wings and TIE Fighters, explode. While we can assume that certain weapons will affect smaller ships differently than their larger counterparts, this disharmony is a bit confusing.

What causes larger ships to 'fall' when blown up in the Star Wars universe?

  • 4
    Repulsor lifts fail? – Edlothiad Dec 15 '17 at 16:29
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    Check out Newton's Third Law and consider, along with the failure of engines and directional control, the effect that an explosion on / out of the superstructure of a craft would be – NKCampbell Dec 15 '17 at 16:39
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    Momentum. Presumably, when a ship explodes, whatever is keeping it stationary/upright/whatever fails. At that point, explosions on the hull will be the primary forces acting on the ship so an explosion on the aft underside of the vessel would push the aft section up and the fore section down causing it to "fall". Explosions elsewhere would cause similar motions. – geewhiz Dec 15 '17 at 16:45
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    Does this happen near a large mass with a strong gravitational pull (i.e. a moon/planet), or does it also happen in deep space? – Moogle Dec 15 '17 at 16:56
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    Out-of-universe: because it looks better on-screen and helps sell the idea that the ship is seriously damaged. – Anthony X Dec 17 '17 at 19:32
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Typically when you're in space above a gravity well, you stay "up" by falling sideways so fast that you just keep circling around the object/planet. That's what it means to be in orbit.

In Star Wars, we rarely see ships in orbit. They usually just hover over a single place. Rather than moving sideways to stay up, they utilize Repulsorlifts to accomplish this feat, directly counteracting the effects of gravity wanting to pull them down.

When a ship is damaged or destroyed however, the repulsorlifts fail. Since there's no longer anything holding them up against gravity, they then begin to fall back towards the object/planet.

Now, regarding the discrepancy between large and small ships. If you launch a missile at a small ship, the power of the explosion compared to the size of the craft is more than enough to blow it into tiny pieces, wherein the force of the explosion launching those pieces every-which-way is more apparent than the pull of gravity for a time. If you were to take that same missile and launch it at a large ship however, it would do substantially less structural damage relative to its size (and impart less relative force), even if it is still capable of doing sufficient critical damage to disable it.

If a small ship were to take critical damage without being blown to tiny pieces, we should expect it to fall just as larger ships do. This just rarely happens.

Lastly, the Death Star was known as an orbital battle station, and it's almost always in orbit when we see it (Yavin, Endor, Jedha, Scarriff). It would make little sense for a craft the size of a small moon to use repulsorlifts, since it has no need to stop above a planet, or lower/raise itself relative to the surface (it's not like it needs to land). So when it explodes, gravity has no apparent effect, because it's acting equally on it the same as it always had been, continuing to fall sideways. The debris we do see falling and burning up are the parts blown towards the planet by the explosion itself.

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    @Mwr247 If you wanted to stay near a part of the planet, you couldn't do it by hovering. You'd have to orbit (geosynchronously), right? – Lord Farquaad Dec 15 '17 at 18:54
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    @LordFarquaad Very much depends on the rotational speed of the planet as well as it's mass. Geosynchronous to Earth is really far out. I didn't mean to imply the ships were stationary though; just that that move in such a way as to remain relatively in position above the point of interest. – Mwr247 Dec 15 '17 at 18:59
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    @Mwr247 gotcha, that makes sense. Keep your engines firing all the time to keep a geosynchronous orbit way lower (a couple miles vs a couple thousand miles)? – Lord Farquaad Dec 15 '17 at 19:08
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    @jpmc26 No, what is required to stay above a specific point on the planet is being in a synchronous orbit or hovering as this answer explains. (Hovering = being lower than synchronous height, so that your orbital period would be shorter than the rotational period, but not orbiting, and making up for it with continuous thrust towards the zenith.) – hobbs Dec 15 '17 at 20:57
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    @jpmc26 "In physics, an orbit is the gravitationally curved trajectory of an object, such as the trajectory of a planet around a star or a natural satellite around a planet.". You can stay above a point on the surface without being in synchronous orbit. Helicopters do it all the time. Being in space makes no difference (aside drag, but that's besides the point). While there are times that they might actually be in orbit (fighting the Death Star most likely), for many of the battles they don't appear to be (above Scarriff being a very apparent example). – Mwr247 Dec 15 '17 at 22:25
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Because Star Wars battles are Naval battles, roughly WW2 era.

What you are seeing is those starships "sinking", like how a large naval ship sinks on a planet.

There may be arbitrary in-world justifications for it. But fundamentally it is the same reason why fighters do banking turns and behave as if they are flying through air, and why bombers "drop" bombs.

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    The incongruity of a space craft acting as it actually would in space would probably be much larger for the viewing audience than that of starships falling while smaller ships simply vaporize. – FreeMan Dec 15 '17 at 20:52
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    When are people going to stop asking us to retcon space opreas that were written in the 70s… – Mazura Dec 15 '17 at 21:08
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    @Mazura or 1960s, like when Kirk tells everyone to be Vewy Quiet so the Romulans can't hear them... – RonJohn Dec 15 '17 at 21:21
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    Banking turns make sense even without an atmosphere, and it causes the g-forces to act "down" i.e. push the pilot into their seat. – Acccumulation Dec 16 '17 at 0:10
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    @Acccumulation: yes, but it would make even more sense to point the tail of the craft backwards, so you're pushed back into your seat. The G limit before you black out that way is significantly higher than for G forces down your body (draining blood from your head into your body / legs). Nevermind the fact that it lets your main engines provide the centripetal force; if we buy your argument then thrusting into a corner like a rocket ship should work even better. In a fighter with forward guns, it also lets you point them inside your turn and shoot someone that broke left in front of you. – Peter Cordes Dec 16 '17 at 4:29
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For the same reasons explosions in space go boom, fighters have wings, and so on*. It's because the writers and directors are either ignorant of physics themselves, or they think they have to appeal to an audience that's ignorant of physics.

*Especially the reason that maybe 99% of Hollywood car crashes result in fires and/or explosions. In the real world, less than 1% of crashes result in fires, and only a small fraction of those result in explosions: https://one.nhtsa.gov/cars/rules/regrev/evaluate/807675.html or visit your local auto wrecking yard and notice how few burned vehicles are brought in.

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    I don't think ignorance of physics is necessary to desire suspension of reality during something like watching a movie. People watch to have fun, whether or not they understand the fiction isn't rooted in physical law doesn't change that. – user1717828 Dec 17 '17 at 16:56
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    @user1717828: I can't speak for anyone else, but that disdain for actual physics is one of the reasons I absolutely refuse to watch "Star Wars" or similar movies. I do have a degree in physics, though. – jamesqf Dec 17 '17 at 19:06
  • I think it's about selling the idea that the ship has been sufficiently damaged to take it out of the fight, without actually blowing it to bits. We can assume that (off-screen) it may subsequently crash into something (moon, planet, another ship) and be totally destroyed anyway, or limp away to fight again another day; either way, it's done for the day and out of the current battle. It may not be an artifact of writing, but perhaps visual effects staff injecting some variety. – Anthony X Dec 17 '17 at 19:41
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    @jamesqf I don't have a degree in physics, but do find myself cringing at the obvious disdain for true physics (sound in space, gravity, etc.), but I also enjoy watching the genre (movies and TV) anyway. They want to make the action and events on screen relatable to an audience accustomed to terrestrial life, so that's what we get. – Anthony X Dec 17 '17 at 19:53
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The Star Wars universe is a movie universe.

The general consensus among movie makers goes like this:

  1. Small vessels get blown apart. This is a departure from classic war movie depiction of aircraft destruction, and serves to demonstrate that the weapons involved are very powerful.

  2. Giant vessels, such as Death Stars, are the point of space battles, and as their destruction signifies the climax of the battle, their end is, well, climactic. Complete destruction.

  3. Merely large vessels, when destroyed, are more visually impressive when the destruction is partial, with an explosion followed by flaming debris. So that's what you get. Here the visual trope is the destruction of capital ships in WWI and WWII.

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    Perhaps add some examples from other movies just to please – JeopardyTempest Dec 16 '17 at 0:37
  • … and said destruction has a two-dimensional wavefront, as added in the Special Edition. (-: – JdeBP Dec 17 '17 at 19:23
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I think the other answers cover the gravity well angle pretty well. Most of the battles we see are in a gravity well of some sort.

It's worth noting that, in The Last Jedi, we see ships outside a gravity well not falling. Most notably

after the suicide hyperspace attack by Admiral Holdo. Note that the "wing" of Snoke's ship, which completely severed, keeps its momentum with the body, but changes yaw (probably from escaping atmosphere)

  • Hang on. By the point of the scene in your spoiler, they are in a gravity well - that was the whole point of the events leading up to it. – Nij Dec 17 '17 at 10:19
  • @Nij Not how gravity works. It would actually be more dramatic realistically, since the ships were accelerating - and would have fallen back relative to the unaffected ships as soon as their engines were disabled. Funnily enough, people would probably bash that as unrealistic :P The gravity well in question was entirely uninteresting - and would be even more so if the ships weren't accelerating; in free fall, all the ships would move at the same speed anyway, so would be stationary with respect to each other - they'd just drift apart slowly. – Luaan Dec 18 '17 at 9:27
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There seem to be a lot of capital ships in the Star Wars universe that have enough power to, as @Mwr247 mentioned, lift themselves and hover about despite gravity. For instance, on Rogue One they have a Star Destroyer hovering over a city without breaking a sweat. And then during the Clone Wars era they landed older models of those starcraft or hovered over some base or installation (to load clones or laundry or whatever). Also, I could swear I saw them flying, the same way that bricks don't, at a very lazy speed at cloud level in one of the shows.

I would wager if you hit the thingie that keeps those ships hovering they will come down.

In space over a planet, unless they are high enough and in the right location (Equator anyone?) to be geosynchronous, to stay motionless above a single point will require some power to keep the lifting thingies lifting.

The Death Star is a manufactured moon with engines. I do wish they played up the gravitational pull effect in the films -- it would be ominous -- but they didn't. But, they probably plan on either orbiting a planet they do not want to destroy -- or they plan to blow it up, in which case they do not care about the orbits.

In some cases you can see small crafts falling back to the ground when they are close enough to it. When they bank to turn, it may also be because of where their main engines are placed: turn the ship around to place main engines where they can provide the thrust you need for the maneuver you want.

protected by Möoz Dec 17 '17 at 21:24

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