FTL without warp drive...time dialation?

Discussion in 'Trek Tech' started by FreddyE, Jul 16, 2014.

  1. FreddyE

    FreddyE Captain Captain

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    I recently watched the episode where Sisko and Jake travel in an bajorian style "sailing" starship. In one scene they are pushed to warp speed by a stream of FTL-particles. Lets assume they were pushed to light speed for what seemed about 10 to 20 seconds. How big would the relativistic effect be? How big time dialation would occour from that few seconds?
     
  2. Christopher

    Christopher Writer Admiral

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    First off, it's dilation, not dialation. I'll never get why so many people hear a fourth syllable there.

    Anyway, you can't be "accelerated" to FTL speeds. Pushing something faster and faster will just cause its relativistic inertial mass to increase toward infinity as it approaches the speed of light, so that it will be impossible to get it to go faster than light. So the tachyon stream "pushing" the sail ship into warp would be an entirely different phenomenon.

    After all, if the tachyons can "push" the sails, then the sails must be of a material that's opaque/reflective to tachyons, and that means the tachyons would have to be instantaneously stopped at the point of impact -- which is impossible, since tachyons can't go slower than light. But the material of the sails can't go faster than light. So there's a paradox if a sublight material is reflecting tachyons. As I see it, the only way to resolve the paradox is if the bubble of spacetime occupied by the sails is distorted so that it travels at effective superluminal speed relative to the surrounding spacetime, carrying the sails within it at sublight speed relative to the spacetime within the bubble. Which is exactly how a warp field works. So the sailship FTL actually is a warp effect after all. And thus it doesn't have time dilation any more than any other warp propulsion.
     
  3. Nebusj

    Nebusj Rear Admiral Rear Admiral

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    Re: FTL without warp drive...time dilation?

    There's not really a way to answer that from real-world considerations: relativity makes it awfully hard to even form a coherent explanation of what a thing moving faster than light would be.

    So you have to fall back on what the show says. What kind of strange time effects were seen when the Siskos did take their journey?
     
  4. Ithekro

    Ithekro Rear Admiral Rear Admiral

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    Since he seemed to arrive at Cardassia relatively soon after he left Bajor...basically no effect based on time...at least no different from a standard warp drive.

    Cardassia is at least a few light years away, so that stream plus sails made for a really fast warp factor without a wormhole. Too bad it was probably only one way, or else they could have had interstellar trade routes based on the tachyon "winds".
     
  5. Timo

    Timo Admiral Admiral

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    It wouldn't be that hard for the Bajoran culture to have undergone major upheavals during its hundreds of millennia of history - from being in control of a vast network of interstellar sailing routes to being remembered as an obscure world of nice architecture and zero technological achievement, say. In the great lengths of time involved, history could have been rewritten several times, by Bajorans and their foes alike.

    All we really know about this is that Sisko thinks the type of sail he built was in use 800 years before the episode. We don't learn if that was the earliest lightsail type known to exist, or perhaps the last, or if lightsails were a passing fad that was preceded by ion-drive bicycles and followed by gravity-gradient surfboards. Nor do we learn whether Bajor had conventional warp concurrently with that particular lightsail type or not.

    That said, yeah, it was a very fast journey from Bajor to Cardassia. Usually, when our heroes travel by runabout, it takes at least several hours of story time, although "Tribunal" appears to feature a very fast journey as well. We might just as well say that the sail traveled slowly for an external observer, and the trip only appeared short for the two people aboard (i.e. traditional time dilation effects but this time due to exotic phenomena rather than Einsteinian relativity).

    Timo Saloniemi
     
  6. Ronald Held

    Ronald Held Rear Admiral Rear Admiral

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    And how does a Bajorian sailship change its local space-time in a tachyon field to allow it to go FTL?
     
  7. Christopher

    Christopher Writer Admiral

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    Re: FTL without warp drive...time dilation?

    Not really. Special Relativity is unable to address the question, but General Relativity's equations allow for the alteration of spacetime topology in ways that can theoretically allow effectively faster-than-light travel. Warp drives, wormholes, space folds, and hyperspace are all ideas derived from the equations and concepts of General Relativity. Einstein himself was one of the people who first conceived of wormholes. Heck, even the idea of tachyons is derived from Special Relativity, because they're the solution that falls out of the equations when you plug velocities above c into them. It's a mistake to say that theories are useless at predicting things beyond the known physical world; on the contrary, mathematical equations can easily describe scenarios far removed from physical reality, because you can easily plug impossible numbers into them. (You can't pick twelve flowers out of a bed of seven, but you can easily write 7 - 12 = -5.) So it's actually pretty easy for theories to describe how things would behave in impossible circumstances.

    So we actually have very good relativistic models for how things moving effectively faster than light would behave; we just have to do the math using the equations of General Relativity instead of the more limited Special Relativity (which is called that because it was only intended to apply to the specific case of unaccelerated motion, as a simpler problem to solve before Einstein moved on to the bigger, more general questions).
     
  8. Nebusj

    Nebusj Rear Admiral Rear Admiral

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    Re: FTL without warp drive...time dilation?

    They're also all things for which there is no observable evidence and requiring the existence of exotic forms of matter with ever-more strange properties to keep being 'not perfectly ruled out'. Note that Einstein's original idea of wormholes was realized to be impossible, though the mathematics took a generation to work out; are you willing to take a bet that the current crop of Fantastic Further Relativistic Notions will survive to, say, 2050 intact?

    Perhaps there is some way to send something faster-than-light. There is not yet any method known to work, so we can't say what would have to happen if one followed this method, for the same reasons we can't say exactly what would happen if a human were to change into the form of a turtle.

    We can make some suppositions about things that would probably follow, but we are talking about something which is, in detail, beyond the bounds of our knowledge. If you want to make up effects, that's fine and dandy and probably fun, but it also means you can make up whatever side effects you want.


    Yes, and they still remain problematic, even past the point that we have no evidence that they exist. Grant that a tachyon is a thing which can travel only at velocities faster than light; given that, how do you have an object made up of more than a single particle made of tachyons? Do both particles interpret the others as tachyons? By what means can they interact?

    And yet, just because you can do a calculation it does not mean that the calculation carries any meaning. When you start doing something new you may easily require new interpretations and new understandings of what is going on. A gas with a temperature of 10 Kelvin is colder than one with a temperature of -10 Kelvin, and it's not twenty degrees of difference between the two. It is a mistake to uncritically accept the apparent predictions of a theory in circumstances very different from what it was developed to predict and in which it has not been tested.
     
  9. Christopher

    Christopher Writer Admiral

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    Re: FTL without warp drive...time dilation?

    Not true, because science doesn't work that way. Since everything follows the same laws of physics, you can extrapolate the way the laws would apply in an exotic context by observing how they apply in known contexts. General Relativity has been consistently verified by every single experiment we've ever thrown at it. Its equations work reliably and consistently. And the predictions of warp drives, wormholes, and the like are derived, not from different, untested equations, but from the very same equations that have been tested extensively -- just with different terms plugged into those equations.

    This is what so many laypeople don't understand about science. They assume you can't know anything about what hasn't been directly observed, but the whole point of theory -- the reason it's such a powerful tool -- is that it allows you to predict things beyond what you've observed. If you can understand the fundamental rules that underlie your observations, then you can figure out how those same rules would apply in a new situation. No, you can't be absolutely certain of how they'd play out in an untested situation because there might be factors you're unaware of, but you can make a prediction that's consistent with everything you do know and that has a good probability of being right. And just about every prediction of General Relativity that's ever been experimentally tested has turned out to be correct.


    Actually more recent work has lent more credence to the possibility of wormholes and warp drives, not less. Theorists have devised potential workarounds to the negative-energy problem and the infinite-energy problem, which were once considered to be insoluble.

    Anyway, you're redefining the question. Of course we can't predict future discoveries, but that's not what you said before. You said, specifically, that relativity could not "form a coherent explanation" of an entity moving faster than light. In fact, most of the theories we have about faster-than-light propulsion come directly from General Relativity. So relativity absolutely can provide an explanation for how we expect objects would behave if they could travel superluminally. No, that doesn't mean we can be sure the explanation is absolutely true, but that's irrelevant, because science never claims absolute certainty. It only makes predictions. And the point is that relativity can and does predict the behavior of FTL entities in quite precise mathematical detail.


    All you're doing is betraying a fundamental misunderstanding of how science works. Deriving predictions from a theory is not "making up effects" -- it's doing mathematics. It's developing equations that explain and codify our observations and make testable predictions. You don't "make up" the results of an equation in new conditions -- you just plug in the numbers and do the calculations. For instance, if you know the equation d = (1/2)at^2 for an object falling under gravity, then you can calculate how long it would take an object to fall from a given height on any planet or moon with any strength of gravity. You wouldn't need to go there and measure it, you wouldn't have to "make up" a result, because it's math and math is consistent and predictable. The only things you make up are the initial conditions, the variables you plug into the equation -- e.g. dropping something from a height of ten kilometers onto a planet with a surface gravity of 8 gees. The results of the computation arise inexorably from the math. And that lets you reliably predict what would happen in conditions you've never actually experienced, even conditions that can't physically exist.

    And again, that's what we're talking about here -- not whether FTL travel is actually possible, but just whether relativistic theory can predict how it would happen if it did occur. And the answer is, yes, it can, and it does. Most of our FTL theories come directly from relativistic equations.
     
  10. Timo

    Timo Admiral Admiral

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    ...Which is an absurd fallacy that is gonna bite us back big time at some point.

    General relativity and quantum physics together are excellent examples of how the world really works:

    1) "Making sense" is not an inherent quality of nature. Science is a way of translating nature to the limited language of human understanding, but it faces an uphill battle it is going to fail soon enough. (Not that we should care. Machines can probably take over the business of understanding and forge fantastic technologies for us from laws of nature we can never hope to comprehend.) Thus we should never fool ourselves into thinking that a "beautiful" or "sensible" theory would be better than others; only testing will tell.
    2) While nature may be consistent "across the board", science is not. Science has regions of applicability, and must have, or it fails in its task of translating nature for us. But the unfortunate thing is that we can't tell what these regions of applicability really are, not until we test them. We can easily test "inward", applying general relativity to a walk across the street or quantum chromodynamics to voltage across a capacitor (but this is also something of a self-satisfying fallacy, because we built those theories to be compatible with the mundane to begin with); we generally can't test "outward" until well after formulating the theory and its numerous competitors.
    3) "Math" is the same as "making sense". It's a human invention that does not stem from the way nature is; this convenience cannot carry us to deeper understanding of nature except within regions of applicability, and see above for the inherent problems. We have had to reinvent math several times already, sometimes for greater convenience, sometimes for better match with nature's weirdness, but it's all part of a struggle against the fundamental aphysicality of apeman counting methods. Using earlier forms of math would not have allowed for current forms of theory; the same is likely to hold true in the future as well.
    4) From the absolute need to test before declaring, it follows that we should view extrapolation across extreme scales not just with skepticism but with contempt. The last time we could claim with a straight face that nature is the same across the board, from the small to the large, from the close to the distant, from the energetic to the static, was more than a century ago. Testing for FTL is beyond our current mandate, and even testing for tachyons is impossible; we cannot reliably recognize the brand of math applicable for the putative phenomenon until we test; and evidence collected on nature so far already indicates such diversity and unpredictability that there soon are going to be too many theories to test for, either randomly or by educated-guess selection. Eventually, we really have to go places "tricorder first", stumbling along empirically, or else we get stuck in really long and winding cul-de-sacs and science grinds to a standstill.

    This is the fundamentally untrue part of your argument. There's no reliability in doing auto-maths, because math doesn't deal with reality. Math is an exceedingly coarse approximation, even when it also is a religiously absolute truth in its own terms. All this blind counting tells you is how your theory will behave in extrapolated conditions; it bears no fundamental connection to how nature will behave there.

    Timo Saloniemi
     
  11. Nebusj

    Nebusj Rear Admiral Rear Admiral

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    Re: FTL without warp drive...time dilation?

    And the prediction gives you something to test when you want to look at a very different condition. When you look into a very different condition from what data went into forming the theory you need to test whether something you did not know about is suddenly more important.

    So, then, if we know the equation d = (1/2) a t^2 for an object falling under gravity, and we know that the acceleration due to gravity is pretty near ten meters per second squared, and we know that an Apollo capsule required roughly 72 hours --- that's about six million seconds --- to journey from the Moon back to the Earth, we may conclude that the Apollo capsule attained a speed of approximately 180,000,000,000,000 meters per second by the time it returned to Earth. After all, we understand very well how things fall and the mathematics would be hard-pressed to be easier to understand or more accessible.

    Unless you want to suppose that the equation d = (1/2) a t^2 for an object falling under gravity is quite correct under certain circumstances but the matter of a spaceship traveling from the moon invokes circumstances in which the equation is no longer reflective of what really happens.


    They begin with relativistic equations, and then must throw in new, exotic things which are not observed to exist, and which may not exist in the real world, or which may exist but which have properties radically different to what we currently imagine. There are many faster-than-light which might be compatible with relativity, but we do not have a way to say that any of them are correct.

    And this is why I am insisting that we can not say what would happen if something went faster than light: if there is a way to travel faster than light, then it requires physics whose details we do not know. An attempt at expanding relativity to handle faster-than-light might be consistent with theory and with observation, or it may be that we haven't yet found the way in which it's not.

    See, again, Einstein: wormholes of the kind he and Nathan Rosen predicted in 1935 won't work; John Wheeler and Robert Fuller found in 1962 that these are unstable, and would pinch closed if anything were to travel through them. Kip Thorne and Michael Morris put forth a new idea of wormholes in the 80s and apparently the idea is not dead yet, despite requiring negative-mass matter; perhaps they are possible, and we're not ten years from a fresh paper showing that Thorne and Morris's wormholes are as impossible (or at least impractical) as Einstein and Rosen's. Perhaps not.

    But you can't tell me what ``will'' happen if you travel a Thorne-Morris wormhole; you can at most tell me that if we suppose Thorne-Morris wormholes to exist as they are presently understood then, this would follow from traveling through one.

    There's other hypothetical wormholes, too, so you can't even insist that if wormholes exist they must be of either Einstein-Rosen ones or the Thorne-Morris ones. There are quite likely many kinds of wormholes one could imagine which would be consistent with present theory and observation, and there's not grounds for preferring one to the other yet.
     
  12. Christopher

    Christopher Writer Admiral

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    Re: FTL without warp drive...time dilation?

    That is true, but it is not the same thing as saying, as you did before, that the theory cannot even allow us to form a "coherent explanation" of an object moving at FTL in the first place. In fact, the theory makes very definite predictions and absolutely does explain why we think an object would behave a certain way in FTL. Explanation is what theories are all about. Whether a theory's predictions can be tested is a different question from whether the predictions can be made at all.


    Yes, and that is exactly my point -- that the fuller Newtonian and Einsteinian theories include more equations that let us predict things beyond direct experience. That's the whole reason we have the concepts of warp drive and wormholes and hyperspace to begin with: because they are results that emerged from the equations of the theory when we plugged in unusual numbers. So it's wrong to say they're just "made up" ideas that relativity says nothing about. They are from relativistic theory in the first place. That's my point. Whether they're true or not is another question; I'm only refuting the assertion that they aren't explained by relativity.


    But the false premise there is that just because we don't know everything, it means we don't know anything. Yes, there are unanswered questions, but that doesn't mean there isn't a lot that we can predict with confidence. We may not know how to create a stable space warp, but we know a lot about what would happen to an object that moved through a stable space warp if one did exist. They're different parts of the question. Yes, there are always new things to be discovered, but they do not erase the things we already know; they just fill in the gaps in what we know.

    Again, whether it's provably true is not the point, because we're talking about fiction and abstract discussions of the possibilities. You said that relativity could not offer any coherent explanations about FTL travel. That is wrong. Almost everything we believe about FTL travel comes from relativistic theory in the first place. It may not be "proven" or "certain" -- neither of which is a term scientists ever use anyway -- but it is definitely a coherent explanation. If someone asks an astrophysicist what they think would happen in an FTL spacewarp, they wouldn't just shrug and make vague handwavey generalizations -- they can do actual mathematics and make very detailed, exact, and coherent predictions, and they can explain in precise detail why they have made those predictions.
     
  13. publiusr

    publiusr Rear Admiral Rear Admiral

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    I thought that, outside a wormhole, the only way to do FTL is if that variable speed of light theory held up. There, you have to travel along a cosmic superstring--which effectively raises the speed limit--a superhighway if you will.

    So does that mean that--if I mastered the waste heat of a nuclear salt water rocket, I could keep accelerating--and what happens if I leave the vicinity of the string and turn away?
     
  14. Christopher

    Christopher Writer Admiral

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    Haven't heard that one. But a wormhole is just one of several spatial topology distortions that would allow bypassing the lightspeed limit. An Alcubierre-style warp drive -- which is basically a Star Trek-style warp drive, though with a ring instead of nacelles -- is another way. Basically you're "surfing" a bubble of normal spacetime containing your ship on a propagating distortion wave in spacetime, since there's no limit to how fast spacetime itself can expand or contract. There are also other variants like the Krasnikov Tube, which is similar to a wormhole in that you create a "tunnel" in spacetime where the internal dimension is small relative to the external one, so you have a shorter distance to travel to get to another star system. Like a wormhole, this would have to be built, probably at slower-than-light speeds and thus taking years or decades to establish, before it could be used.
     
  15. Tim Walker

    Tim Walker Fleet Captain Fleet Captain

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    If this is the Trek universe, you switch over to warp drive.
     
  16. Maurice

    Maurice Vice Admiral Admiral

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    Since "dial" [ˈdī(-ə)l] sounds like tile [ˈtī(-ə)l], when people hear "dilation" perhaps their go-to for writing the beginning sound of "dilation" is the word "dial", as opposed to hearing an extra syllable.
     
  17. Christopher

    Christopher Writer Admiral

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    ^But when the word is spoken aloud, it doesn't sound like "dial" because the L has a vowel following it and thus has a "beginning L" sound rather than a "final L" sound. So it sounds like "dye-lation."

    Maybe they're thinking of the sound of "violation." That's a more common and familiar word.
     
  18. Maurice

    Maurice Vice Admiral Admiral

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    You're expecting a lot from a populace which writes "your" to mean "you're". ;)
     
  19. Lord Manitou

    Lord Manitou Commander Red Shirt

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    I once said before concerning this thread that FTL can be explained by an acceleration toward a source of light and what Einstein has proven is not proven yet. If someone ever understands these realities he will mathematically write them out to make a more solid base.
     
  20. sojourner

    sojourner Admiral Admiral

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    Um, what????