I figured this was the best place for this thread as it involves science and literature and TV & movies and quite a bit of theory and conjecture.
You are in a spaceship traveling at 5X the speed of light. Of course you have a warp bubble around you that allows you to do this because within the bubble nothing exceeds c. All of the sudden, the warp bubble collapses. What happens to the ship?
For a real answer to this, you’d need to know how the warp bubble works, and what it means for it to collapse.
But the most plausible answers are “The ship is destroyed”, “The ship is forever lost in the space between spaces”, or “The ship is suddenly back in normal space with whatever velocity it had before the warp drive was engaged”.
Oh, and note that in Star Trek, Warp Factor 5 is a lot more than 5 times the speed of light. The official formulas varied in different editions of the show, and the episodes weren’t consistent, but the warp scale has always been nonlinear.
You fall out of warp into normal space. Or everyone dies. One of those. Whatever the script demands.
Ninja’d to note that a third option of “stuck in limbo” also exists.
The same thing that happens when they exit warp speed. The ship moves at the same acceleration (or velocity in TV physics) as it did when it entered warp.
That’s why the question is here and not FQ or even GD.
FTR, although I expect posters will pull in ideas from media, the intention is what would happen in real space not fictional space.
But observationally, isn’t the bubble just manually collapsed by the crew when they want to exit warp?
From the various shows, ships “fall out of warp” in lots of ways and the answer seems to be
I don’t recall if any of them specifically involve the “collapse” of the warp bubble but I’d be surprised if none of them do.
Based on what little plausible science there is here and the aforementioned shows, if the ship is otherwise structurally intact and under control, it will just fall out of warp and back into regular space at whatever impulse speed.
So let me get this straight: you want to know what happens in the real universe when a fictional scientific concept in a fictional universe breaks down?
For my best attempt at a real-world answer, I’d say it’s probably a combination of my answers 1 and 3. Whatever a warp bubble is, it would presumably involve ludicrously huge curvature of spacetime (and hence ludicrously huge tidal forces) at its edge. Under normal operating conditions, the engines (however they work) must be very precariously balancing matters to keep such region of ludicrous curvature away from the ship and its crew, and at the end of a nominal journey, would very carefully and precisely smooth spacetime back out. But if something sudden, unexpected, and traumatic happens to “collapse” the bubble, that precarious balance is gone, and I’d expect the resulting tidal forces to rip through the ship and shred it to at least the atomic level. And the resulting expanding cloud of plasma would then be in normal space, with its center of mass moving at the same velocity that the ship had before establishing the bubble.
Well, there’s a real-world physical model for ‘warp drive’ type of devices, known as the Alcubierre drive. This is a valid solution to the Einstein equations, however, it depends on conditions (negative energy density) typically thought to be unphysical. Setting those aside, though, it’s perfectly possible to compute what happens when such a ‘warp bubble’ collapses, and people have indeed done so. However, at a first scan, they’re more interested in whether there might be an observable gravitational wave signature from such events (answer: yes, but not with current gravitational wave detectors, since the frequency of the signal is higher than they can resolve), not in what happens to the ship. But interestingly, there seems to be a remnant of the collapsed bubble that just persists—but I don’t know whether that would be a real barrier of presumably high tidal forces that tear matter apart, or how exactly that would manifest. (Also, they only investigated ships moving at sublight speed, I think.)
Hmm, however, it seems to me that since anything within an Alcubierre bubble effectively follows a geodesic, that is, experiences freefall even during acceleration, there probably shouldn’t be any issue during collapse, at least suitably far from the bubble wall. But I’m on very thin ice here.
In Star Trek it really depends on what the plot requires. The warp bubble just does not collapse like that I(not)RL normally, but losing the bubble can throw a ship out of warp sometimes spinning a bit as it ‘pops’ out of warp back into normal space. Sort of like any ship leaves warp, but a bit more uncontrolled. Also there seems to be the possibility of coasting a bit at warp sometimes, like when the saucer section of STTNG separated at warp but has no ability to maintain its bubble.
Just found this:
So it would seem while the warp system keeps the bubble open, it does not instantly go away but it is no longer being maintained to stay open, so like a boat up on plane when engine power is cut will remain on plane till it falls back to displacement.
There is a physical plausible-ish theory (using the Einstein field equations of general relativity, so not just made up by screenwriters) that allows for the Star Trek ‘warp drive’:
The question of conservation of momentum is a valid question; since the ship itself is moving (within its ‘warp bubble’ which is a disconnected area of spacetime) faster than c it is creating dislocations in spacetime where there are no longer causal connections, and the ‘warp field’ must somehow absorb rapid changes in gravitational gradients and changes in momentum for anything entering or leaving the ‘warp field’, especially anywhere near a massive body. Presumably the warp drive ‘heals’ the space behind it so not to leave these discontinuities but this would create large gravitational waves, essentially a bow shock in spacetime trailing the starship which at close proximity could shred matter.
The larger problem is that even stars in the same group are often moving at high speeds relative to one another (on the order of many tens of km/s) so if the ship had the same components of momentum as it did when entering the warp bubble it would likely be moving at a high velocity relative to its destination; therefore, it must have some way of compensating to match the near-zero velocity relative to the reference frame of its destination. When you start calculating how much energy it would take to compensate for a change in velocity for a vessel the size of a starship the numbers are astonishing, and that is even before you get to the energy to somehow create and propagate a ‘warp bubble’. Even antimatter is probably not a sufficiently dense energy source to male this workable.
Setting aside the plausibility of powering such a system, the sudden collapse of a ‘warp bubble’ would create enormous gravitational gradients (not just from the moving mass of the ship itself but all of the energy to construct the ‘warp bubble’), which would be radiated away as high frequency gravitational waves similar to those of colliding black holes or neutron stars except from a more complex shaped field. Unless that field is convex and has small deviations in curvature some portion of that gravitational wave is going to be reflected back to the ship, creating powerful tidal gradients that should shred the ship and pulp the occupants.
The Star Trek franchise is very inconsistent about how it describes the workings of ‘warp drive’, and never seems to have problems with ships suddenly exploding from minor glitches in the control of the field or activating it too close to another ship, massive object, or just a bunch of undetected dust (unless the plot requires it) so who knows how it actually works except that it basically space wizard magic. And yet, it is only the fifth or sixth most implausible conceit of the Star Trek narrative universe notwithstanding the fundamental problems that a faster-than-light system would have with causality.
Stranger
Which would, of course, be an absolute disaster.
Think about it. You’re traveling along in your FTL starship between two worlds that are twenty light years apart. But thanks to your warp drive you can travel this distance in two days. No problem.
And then mid-voyage, your warp drive breaks down and dumps you into normal space.
You’re now stranded several light years away from any planet with a impulse drive that only produce sub-light speed travel. You’re decades away from the closest world. Your ship doesn’t have the supplies to keep you alive that long.
I don’t recall the source (probably the same), but that’s why photon torpedoes can be used in superluminal flight: they pick up a residual warp bubble from the launching ship and preserve it longer than normal warp field decay with a “warp sustainer”.
But it’s OK, you still have superluminal communications so you can call for and receive help in a reasonable amount of time.
Compare this to Verner Vinge’s “Zones of Thought” universe, where the ability to do FTL is a function of where you are in the galaxy, and if you cross the boundary between the Beyond (where FTL is physically possible) and the Slow Zone (where FTL is impossible), you’re stuck. Which is why “bottom luggers” which operate close to the boundary are also sublight ram ships with extensive suspended animation facilities, so that you can slowly make it back from a mistake like that.
Unless, of course, you’re in one of the recent Star Trek films, in which case it’s a good thing your warp bubble collapsed when it did, because it happened just as you were reaching your destination, and if it hadn’t, you’d have far overshot it.
I would like to believe that in real-life, everything would immediately be transformed into tachyons traveling at 5c.
Addressing this, in a different FTL franchise (Star Wars, at least in the TT-RPG), this is why larger vessels carry secondary FTL drives. If the primary fails, the secondary (generally smaller, cheaper, and much slower) can be used to limp to the closest nearby source of help.
IMHO, I think that the common scenario mentioned of “dropping back into normal space at the prior sublight speed” ALSO ends up being “The ship is destroyed”.
I tend to assume that the bubble is going to collapse rather than evaporate, so portions of your ship will re-enter normal space micro moments apart - which means you’re going to end up a fine chiffonade of starship and crew.
To re-enter intact seems to be a sort of controlled crash, where you’re able to safely collapse the bubble (using whatever means are normal) right BEFORE an uncontrolled collapse.
Minor niggle, but there are a number of sci-fi series (Honor Harrington and some other Weber works for examples) where there are “bands” of hyperspace, and going up and down between the layers can cause failure, and since the grav sink tech is based on bleeding off the excess energy into hyperspace, any mis-step in timing equals instant gravy mode.
So, if:
And there’s NO control of what happened, I think almost any scenario = total destruction.
Any long extant space going culture though probably is going to prepare a number of more survivable failure modes which lead to the other conclusions you mention, but an unexpected, complete failure is likely to be 99.999% fatal.
On the other hand, as long as the destination is far enough away and the speed differential is firmly non-relativistic even if large, then if you did have the energy, then you wouldn’t need an artificial gravity generator since you could simply accelerate within the warp bubble at a rate similar to G and thus change your final velocity.
But that begs the question of acceleration with respect to what reference frame? A Star Trek ship in ‘warp’ would be causally disconnected from the surrounding space (how they can see stars zipping around them, and especially to aft is an unanswered question) and accelerating within the ‘warp bubble’ doesn’t change the net momentum of the system unless the warp drive is somehow compensating for the change in momentum relative to the beginning and ending reference frames. (It is also unclear how ‘impulse engines’ work; despite the name they appear to be reactionless although also capable of emitting exhaust, so ???). In essence, despite the Alcubierre metric being mathematically workable within the framework of general relativity, the way ‘warp drive’ is treated in Star Trek is essentially magical. But just given the energy that must be generated (and the negative energy density required to create a ‘warp bubble’) you can readily infer that the sudden and uncontrolled collapse should be highly detrimental to the ship and its occupants.
The causality problems of traveling faster than light (in essence, the ship is moving backward in time, abd a round trip should result in returning to the past) remain regardless.
Stranger
I was trying to remember whether the ship actually moves through space in its warp bubble or whether it effectively moves the universe around it, but then I realized that was the science of Futurama.