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In my planned fantasy story, the protagonists must escape a dangerous situation by teleporting the ship they're on (a kind of steam-powered ocean liner) into outer space, then back to the ocean surface in a different location. The ship remains in outer space for about 12-15 seconds (which is about how long people can survive without oxygen). I won't go into the mechanics of the teleportation, except to say that it is done by magic, and involves exchanging everything in a certain radius around the object being transported with everything in an identically-sized zone at the destination location.

(Edit: Because of the particular circumstances they find themselves in, they aren't able to select a precise destination for the spell (out of all possible locations in the entire universe), and they're therefore most likely statistically to end up in deep space somewhere. They do have enough control over the spell that sends them back to Earth that they can be sure of returning; it's only the first spell that's completely uncontrolled.)

The problem is that all the oxygen that was surrounding the ship will have dispersed into space, so when they teleport back into the atmosphere, there will be a huge vacuum surrounding the ship that will instantly collapse. As far as I can tell, this would be devastating on a massive scale; the ship would likely be capsized or even destroyed, and everyone on board would be most likely killed or severely injured at the least.

How can I avoid the horrendous consequences the crew would experience in teleporting back into the atmosphere, or at least ensure that the boat remains intact and that as many people survive as possible?

I should mention that even if people sustained grievous injuries that could be fatal given time, it isn't necessarily a problem for the story, since there are supplies of healing elixir on board that can swiftly heal any recent injury. As long as the elixir is administered quickly enough to those who've been fatally injured, they should fully heal within the course of a few minutes. It's becomes a problem when either 100% of the people are grievously injured (meaning no one is well enough to find the elixir and administer it) or killed instantly (meaning there might as well be no elixir at all).

Another thought I had is that perhaps the mechanics of the teleportation cause the air to enter the space around the ship gradually, but it'd have to do so quickly enough that people don't suffocate from being denied air for too long. Also, it'd have to be a natural byproduct of how the spell functions, since nobody in this world has ever been to space before and has no knowledge of the associated dangers of teleporting from a vacuum into atmosphere. But I don't know what justifiable reason there might be for the spell functioning this way.

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  • $\begingroup$ Comments are not for extended discussion; this conversation has been moved to chat. $\endgroup$
    – L.Dutch
    May 26 at 11:24
  • $\begingroup$ Aside note: If matter is swapped with the near-vacuum of space, you'll get a pretty catastrophic implosion at the place where the ship departs. A bubble of air replaced with vacuum will create a strong shockwave (similar to fuel-air bombs), a half-bubble of water replaced with vacuum will have a shaped-charge effect (going upwards but still). This kind of technology would be weaponized by anybody who knows it. $\endgroup$
    – toolforger
    May 29 at 7:33

9 Answers 9

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Instead of space, go to the upper atmosphere

The upper atmosphere is less dense, but that may very well be enough to substantially neutralize the destructive pressure wave you get when returning from a vacuum.

This seems like a pretty reasonable idea for a couple of reasons:

First: go up high enough, and the ship can free-fall for 15 seconds. A web calculator suggests that the ship would fall ~3,620 feet if it fell for 15 seconds. For comparison, the web suggests that humans can breathe just fine up to ~20,000 feet, which is around 5 times the height you need for this fall.

Second: people who are unaware of the vacuum of space are by definition ignorant that the atmosphere ends at all, which likely means that they wouldn't know to make their spell target a region outside the atmosphere. The intent of such people might very well be to just "go up really high." That is, this spell only has to teleport these ignorant people into a region of hard vacuum if you choose to insist that it does.

I think you can avoid the catastrophic pressure wave by deliberately construing the intent of the spell in a way that is more consistent with their incomplete understanding of space.

Also, since this is magic, you do not need to insist that the ship's momentum be preserved by the teleportation.

This does mean that the occupants and objects on the vessel will experience weightlessness for 15 seconds. That is far less dangerous than a devastating pressure wave, but can present its own challenges. It would certainly make for an interesting interlude in a story, as well as an opportunity to spring a new problem on them. As they say: out of the frying pan, into the fire.

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  • $\begingroup$ I really like this idea, although as in the comment I made in the other answer, they have no control over where they end up. It's my fault for not making that clear. If I can't find a way to resolve the difficulties inherent in my premise, I will change it so they find a way to teleport themselves into the upper atmosphere. Since teleportation in this universe requires two linked objects, they'd probably have to use magic to launch something very high and then complete the spell. But then there's the matter of how they're supposed to get down... $\endgroup$
    – Skallod
    May 25 at 2:48
  • $\begingroup$ @Skallod What if the Moon is magically linked to something somehow which can be used to anchor the teleportation mechanic? $\endgroup$ May 26 at 17:27
  • $\begingroup$ You still have the far more destructive pressure wave caused by all of the water dispersing! $\endgroup$
    – user253751
    May 27 at 16:13
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Change route

Instead of going up, go down.

Teleport into the crust.

You will make a cave a few kikometers deep into the crust. It will be hell hot, but the ceiling could last longer than fifteen seconds before collapsing, and the air should keep the temperature survivable for a while. Then teleport to wherever and you're safe.

Plus, if you are being followed, whomever is chasing you will suddenly have to deal with a rogue wave due to the immense boulder you've dropped on the water where you once were.

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    $\begingroup$ For reasons I won't go into, they don't have any control over where the first teleportation sends them. They do have control over their ability to get back, but they can't choose where in the entire universe they will end up, which is statistically most likely to be empty space. I now realize that I should have made this clearer in my initial question, and I'll be adding that in. I very much appreciate the suggestion though, and if I end up making a major shift to how this scene works, I'll keep it in mind. $\endgroup$
    – Skallod
    May 25 at 2:41
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    $\begingroup$ This is probably actually the best bet for survivability. The water will be teleported along with the ship, and while it might heat up in 12 seconds it shouldn't be enough to be catastrophic unless you teleport into magma. $\endgroup$
    – aslum
    May 25 at 16:10
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They shelter in a watertight compartment below decks.

hatch

Big ships have such compartments to reduce flooding and improve buoyancy. Here they would serve double duty. Your characters get in one before they jump to vacuum. When they come back it is very loud and tough on the ship but they stay safe.

When they are in the vacuum they will know it because every pore that air can escape through will start to shriek and whistle. They have wet clothes around the door but there are other places not quite airtight. You can have a character put a thumb on one. And then back off. And back on. wah-wah-waaahhhh...

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  • $\begingroup$ This is exactly what most of the passengers and crew will be doing. But there are a few people who have to remain on deck, including the protagonists. $\endgroup$
    – Skallod
    May 26 at 2:35
  • $\begingroup$ Maybe the bar has a refrigerator they could shelter in? Big cooler? Hot tub with the cover on? $\endgroup$
    – Willk
    May 26 at 20:46
  • $\begingroup$ That's pretty dangerous. Any airtight compartments will suddenly have to withstand inside pressure instead of the outside pressure they're usually built for. Also, if you have a bridge with glass windows, these will likely burst, unless the bridge door was kept open. (As will the lungs of anybody who closes off his lungs to gas - "preparing for vacuum" will do your soft tissues no good, there will be pressure differentials they aren't built to sustain.) $\endgroup$
    – toolforger
    May 27 at 10:59
  • $\begingroup$ @toolforger - of those pretty dangerous situations, I thought sheltering in the airtight compartment seems like the best bet. $\endgroup$
    – Willk
    May 27 at 18:35
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12-15 seconds are not enough to completely bring a large sphere in pressure equilibrium with the vacuum surrounding it, and that is more true the larger the sphere is.

Also, the higher pressure differential will happen at the border of the sphere where you have no ship, while the inner layers will take more time to balance and will act as a buffer when the pressure bounces back to normal.

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    $\begingroup$ Air can get to the center of a 300m-diameter sphere in 15s by moving at a breezy 10 m/s (20mph). Even the most violent winds on earth (~250mph) are generated by pressure differences of only about 0.1 atm. A full atmosphere of pressure differential will make the air move considerably faster, I don't see it taking very long at all to approach equilibrium. $\endgroup$ May 25 at 18:42
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    $\begingroup$ This sounds like a great question for xkcd, but yeah, I can't fathom it taking more than a second for the air to disperse enough to be useless for breathing purposes. But I wonder if the fact that it's going in every direction, all at once, with no containment, might make it a much less violent event. Just kinda poof and now you're in a loose nebula of air. $\endgroup$
    – JamieB
    May 26 at 14:03
  • $\begingroup$ The air rushing outward will also have some momentum to counteract the air rushing inwards after 15s… but I guess the spherical geometry means the effect won't be much good $\endgroup$
    – Bergi
    May 27 at 8:52
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    $\begingroup$ @JamieB from the OP's set up, their not too worried about breathing while in space, relying on exposure to vacuum not being instantly fatal, instead they're worried about dropping a sphere of vacuum back into the atmosphere and what happens when a sledgehammer of air rushes to fill that vacuum. Oh, and here is the XKCD; what-if.xkcd.com/6 $\endgroup$
    – Jontia
    May 27 at 12:52
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Water surging back as the ship falls is going to be the real danger.

Returning air isn't going to be the problem. Consider a ship 150 meters long (I'm using the MS Batory, circa 1935 as likely guess for the size your ship), if the displacement is exactly a sphere centered on the ship, you'll have a 75m radius sphere of displacement. The ship will materialize over 60m above the water. It immediately will begin falling, meanwhile the water will surge in to fill the gap. Assuming the water rises just as fast as the ship falls they'll collide a little over 2 seconds later at over 40m/s (~90mph!).

While there'll likely be enough upwards force from the water to arrest motion of the ship, the water around the ship will easily push past the ship in a catastrophic manner. Put simply this would end up being the fastest sinking of a ship ever.

A smaller vessel will likely have a much higher chance of not becoming submerged within but a few seconds. Ideally you'll want a roughly circular ship with as deep of a draught as possible.

Alternatively, if your spell displaces in prolate spheroid (think american football) your chances of not floundering and sinking are much improved, but there'd still be significant risk. Also a potential for worry is if there are masts/antennae that protrude taller than your spells spheroid of influence they may get severed in the initial translation (this could be an interesting plot point).

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  • $\begingroup$ The teleportation area is likely to be a prolate spheroid, or a sort of rounded rectangle around the ship. $\endgroup$
    – Skallod
    May 26 at 2:01
  • $\begingroup$ If you're going w/ steampunk you could easily have it be a fairly short paddle boat, with wheels on the sides... the extra width would reduce chance of floundering (though the wheels well might get damaged). Then you could have it be more of an oblate spheroid (wide circumference but not tall/deep). $\endgroup$
    – aslum
    May 26 at 2:06
  • $\begingroup$ I like this idea. I was already considering making it that kind of ship, so this just gives me even more reason to do so. $\endgroup$
    – Skallod
    May 26 at 2:38
  • $\begingroup$ But the water from the first location would still be there around the ship. It won't disperse nearly as quickly as the air. $\endgroup$ May 27 at 16:18
  • $\begingroup$ @NickMatteo Only if the ship is motionless relative to the water (eg sitting in a pond). Even if the ship is travelling at a leisurely 5 km/h that's still 25m in 15 seconds. Having some of the water there would probably be worse then all or none since the ship would tip into the gap. So ideal situation would likely be at rest relative to the current. You'd get some dispersion, but it would be less catastrophic. $\endgroup$
    – aslum
    May 27 at 17:12
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By magic

I'd suggest the allmighty handwave of magic, if nothing else seems possible. Someone capable of teleporting a large mass to anywhere in the universe must surely be able to create a force field capable of holding the teleported content for 12-15 seconds? If I had mastered a spell that teleported me into space, I would probably also have tried to work out how to survive it. I don't know under which premises "magic" works in your world, but as soon as I hear the word used as an explanation, I just assume that anything is possible just at the moment where it is needed for the plot.

An explanation using the mechanics of the spell would be if the appearance weren't quite instantaneous. As if they squeezed out from a singularity of the four-dimensional spacetime or something. I don't know exactly how unpleasant creating a large bubble of vaccuum on earth would be, estimates on forums on the internet varies from moderate to destructive. Anyhow, even a small fraction of a second of delay would greatly decrease the chance of broken eardrums among the crew.

I'd add that the crew would probably be in pretty bad shape after only a couple of seconds in space, even after just an instant. Saying that people can survive 12-15 seconds in space is kinda like saying they could survive as many seconds after falling into a meat grinder, provided they landed feet first. The low pressure of space would cause all the liquid in your body to boil, if not for the tissue keeping it under pressure. Bubbles would form in your blood and block vessels in your brain, among other things. This is also what happens when divers are ascending from great depths too fast.

Also; teleporting to anywhere in the universe would by "conventional" means requires unimaginable quantities of energy and/or mass. If spells in this world is capable of accomplishing feats like this, they would have incredible potential for doing other things too, if there is any consistency in that regard. Saying that someone could teleport a large mass faster than the speed of light, might also be implying that they would be able to disintegrate the earth on a whim, for example. Unless your magic works in a different, mysterious way that doesn't at all relate to physics as we know it. All in all, I'd say there is hope of saving your crew by the same magic that threatens to destroy them.

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    $\begingroup$ Jim Leblanc survived (with no lasting effects) exposure to hard vacuum for 14 seconds before he lost consciousness. He was given an air-supply around 10 seconds after that by a colleague and made a full recovery almost immediately with nothing worse than a headache. So half a minute of exposure to space-like vacuum is essentially harmless to a healthy adult human provided you get repressurised and air'd immediately. $\endgroup$
    – Ruadhan
    May 25 at 14:48
  • $\begingroup$ Oh, they're going to suffer alright. The consequences of this manoeuvre are meant to be fairly devastating. Some amount of injury (like burst eardrums) can be healed by magic. The main issue in this scene would be if incapacitating and fatal injury were guaranteed for everyone, since nobody would be left to help heal those worst off. $\endgroup$
    – Skallod
    May 26 at 1:56
  • $\begingroup$ @Ruadhan The Leblanc story is a really useful example, but in his case the depressurization was gradual, so I'm not sure if there'd be worse effects in somebody who experienced violent and sudden depressurization. Exposure to cosmic rays might also cause lasting effects. $\endgroup$
    – Skallod
    May 26 at 1:59
  • $\begingroup$ I'm mostly trying to figure out whether the bubble of vacuum would instantly kill everyone, since it is rather large, and they're right at the centre of it. It might also destroy or capsize the ship, and it's already bad enough that the ship will probably be falling into the water some distance. $\endgroup$
    – Skallod
    May 26 at 2:04
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    $\begingroup$ This is the right answer IMO. If you're OK with handwaving away "oh, they have magical healing elixirs on board which can heal whatever wounds they sustain" then you can handwave away the physics of what would happen to the air when they teleported back from space far more easily. It's magic, therefore it behaves how the plot requires it to behave. $\endgroup$
    – kaya3
    May 26 at 20:58
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Challenge: The question may be moot, because physics won't do what you expect

all the oxygen that was surrounding the ship will have dispersed into space

Are you sure about that? This obviously will depend on the size of the sphere of air, of course. I don't have the maths to prove it, but I strongly suspect you wouldn't have full dispersal of all the atmosphere within a volume of air with half-liner-length radius in 10-15s. At which point the shock wave from coming back would be reduced, because you wouldn't have 1 ATM of pressure difference.

there will be a huge vacuum surrounding the ship that will instantly collapse

Nothing happens instantly. Sure, the pressure differential means that air flows rapidly into the vacuum. However it can only do that progressively. Quickly, sure, but progressively.

There is also no physical reason why there should be damage to the ship as a result of this. Air enters the volume from all directions, so there is no shock wave affecting the ship or its passengers. From outside the sphere, there will likely be an audible "bang". Inside the sphere, the reduced pressure (or even complete vacuum) means you won't actually hear much if anything.

Your biggest problem is actually anything which is airtight but doesn't have a robust seal. Ears, sinuses, dental fillings, and anything else where divers can get a "squeeze", could be damaged by fairly rapid changes of pressure. That equates to a 10m depth of water, where divers would normally equalise their mask and ears going down that distance. Expect a reasonable number of hospital cases for this, although none will be fatal.

Your biggest threat to the liner is if it's no longer floating on a body of water. Ships don't like being unsupported, and tend to "break their back" when that happens, so you'd better hope that all the water comes back in the same shape it left. 10-15s shouldn't be enough time for the water to go anywhere significant though.

Challenge: Supposing there was this pressure shock though, this isn't your first problem

teleporting the ship they're on (a kind of steam-powered ocean liner) into outer space

would give an instant 1 ATM pressure difference. If a pressure shock was going to occur, it's already happened (within the sphere of teleported air) as soon as the liner hit space. So the issue of how to return to Earth safely is kind of irrelevant, if this is the case. Everyone died explosively 15s earlier, end of story.

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    $\begingroup$ I was under the impression that people could survive explosive decompression as long as they didn't hold their breath. I also read that an instant vacuum, even at a small scale (like an instant human shaped-vacuum) would be like a bomb going off, though I've seen incredibly contradicting opinions on how devastating it would be. Some people claim it would do next to nothing but produce a loud noise, while others think it would kill everyone in the vicinity. $\endgroup$
    – Skallod
    May 25 at 17:34
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    $\begingroup$ I'd expect air to accelerate to the speed of sound pretty darn quickly - there's 100,000 newtons of force pushing on every square meter of air-vacuum interface. By W=Fd, millions of joules worth of energy will be released quite suddenly - generating just 1 cubic meter of vacuum against atmospheric pressure takes about 100 kJ. I certainly wouldn't want to be around any situation with energy changes equivalent to several kg of TNT going off. $\endgroup$ May 25 at 18:08
  • $\begingroup$ @NuclearHoagie But could anybody actually survive that? Where would the brunt of the force be situated; at the edges of the oxygen cloud, or all throughout it? $\endgroup$
    – Skallod
    May 26 at 1:51
  • $\begingroup$ Also, there's a difference between going from one atmosphere to zero atmospheres, and going from multiple atmospheres to one atmosphere. The horrific Byford Dolphin diving accident involved instantaneous decompression from nine atmospheres to one, causing instant death for most of those involved. Going from one atmosphere to zero is a totally different situation, and much less likely to cause death. tvtropes.org/pmwiki/pmwiki.php/Main/ExplosiveDecompression $\endgroup$
    – Skallod
    May 26 at 2:30
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    $\begingroup$ @Skallod The force would propagate inwards as air rushes to fill the vacuum sphere, the force will be felt wherever there's still a pressure differential. As the air fills the void, you'd get a big pressure spike near the center as the shell of air moving at Mach 1 collides with anything, either itself or the somewhat-still-pressurized ship. I don't buy the argument that there's no damage since air enters from all directions - it's like saying it won't hurt if I punch you in both sides of the head simultaneously. $\endgroup$ May 26 at 13:24
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Perhaps the teleportation works by first forming an impermeable bubble around the source and destination, which lasts for about 15 seconds before breaking down after their contents are swapped. a.k.a. Bubble Teleportation.

enter image description here

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If you need to exchange matter, outer space should not be a valid target, as vacuum is not matter.

However, what about an asteroid ? This is still outer space, so your statement is valid. If they teleport at the "top" of an asteroid, and only a small part of the teleportation bubble is opened to the vacuum, the air would probably not disappear instantly (I'm guessing pretty fast, but probably not instant), that would give you a few more seconds.

Also, if some of the crew is inside the ship, it would probably be way safer for them than for people standing on deck.

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    $\begingroup$ 1. They can't choose where they end up for the first teleportation. 2. They're not exchanging vacuum; it's more like they're exchanging all the air out of the target destination, which can't really be got around because of how teleportation works in this universe. $\endgroup$
    – Skallod
    May 25 at 17:39
  • $\begingroup$ I see your point, but I'm not convinced it's valid. You're taking the idea of "exchanging matter" too literally. In other words, you're assuming that because there's no matter to exchange in space, the teleportation can't take place. If all the magic (entirely defined by the OP) does is move whatever it finds in sphere A to sphere B, and whatever it finds in sphere B to sphere A, then you have the situation the OP is talking about. (Otherwise you'd have trouble with terrestrial teleportation due to the density difference between atmosphere and dirt.) $\endgroup$
    – JBH
    May 26 at 6:48
  • $\begingroup$ @JoinJBHonCodidact "vacuum" is not "no matter", it's just the human term for "an area with very little matter in it". E.g. near-Earth space still has 10^5...10^8 molecules per cm³. $\endgroup$
    – toolforger
    May 27 at 11:26
  • $\begingroup$ Just think of it as exchanging the content of two (let's assume spherical for convenience) volumes. $\endgroup$
    – Corey
    May 28 at 2:13
  • $\begingroup$ @toolforger, the salient point in your comment is the word "area." The contents (or lack of contents) are being exchanged. At least that's how the Q reads to me. If the available mass at point A is exchanged with the available mass at point B, the result is that vacuum at A is suddenly filled and the area at point B suddenly becomes a vacuum. $\endgroup$
    – JBH
    May 28 at 4:01

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