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Warp drive, then where are we?

  1. Apr 19, 2005 #1
    Hey guys;

    Say that yesterday someone invented a warp drive, that would allow you to shoot across our galaxy in an instant. Say we went up in space today and used it. When you appeared at what you would think would be the other side of the galaxy, how would you know where you are?

    My point is: If such a technology even was invented, wouldn't you be all but lost when you got to your destination? Any "signals" coming from Earth to let you know where you are would take however many billion years to reach you. Would you effectivly be lost? Or would there be other mechanisms to locate yourself? (Star locations, etc)
     
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  3. Apr 19, 2005 #2

    SpaceTiger

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    If such a technology existed, then locating yourself from the stars and galaxies would be a relatively trivial matter (particularly if you were smart enough to make a warp drive). However, current physics suggests that warp drive is not possible.
     
  4. Apr 19, 2005 #3
    Well, if the warp drive aloud you to go pass the speed of light and you knew how fast you were traveling and how long you traveled plus the direction you went in, they you could easily find your location.

    Other than that, possibly by use of star charts you could locate yourself, but then again stars can look very different in different locations because stars will be in different locations not only because you moved but also because you are closer/further to them so you are seeing "younger" or "older" light coming from them.
     
  5. Apr 19, 2005 #4

    ohwilleke

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    A guy who doesn't bring a map with him on a galactic length journey, and doesn't know which direction and distance he was travelling in to start with, to give him a good hint about where he will be, deserves to be lost.
     
  6. Apr 19, 2005 #5
    He, or she, could use the Hitchhiker's Guide to the Universe. :wink: I agree with Ohwilleke, anybody who wouldn't bring a bloody map with them is daft.

    SpaceTiger does have a point in stating current physics points out no such machine is possible.
     
  7. Apr 19, 2005 #6

    DaveC426913

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    Actually, current physics does NOT make such a machine impossible.

    It makes FTL drives impossible, but not warp drives.

    FTL (faster-than-light) drives by definition exceed c.

    Warp drives create or make use of wormholes to warp space, making the distance between 'there' and 'here' smaller and traversable without exceeding c.

    Nothing in modern day physics says this can't be done. In fact, Einstein's equations predict it as a possibility. (Then again, they also predict that time travel is possible.)
     
  8. Apr 19, 2005 #7
    If anything were to exceed c wouldn't it just turn into energy?
     
  9. Apr 20, 2005 #8

    Phobos

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    The whole of the galaxy is made of the same stuff we see on this side....stars, nebulae, etc.

    You may just not know the local layout of stuff (particularly on the other side of the galaxy where we don't have a clear view from here....the galactic center obscures our view of the other side).

    Presumably, you would target a specific location for your journey. Either you would know it beforehand through observations or you would map it out once you got there relative to areas you do know about. If you did a random shot, then although you might not have any idea about local conditions, you could still easily find the galactic plane and center merely by looking (and thereby orienting yourself) and then you could look outward toward other galaxies and figure out your new position relative to the view you had of those galaxies back on Earth.

    The galaxy is about 100,000 light years across, so an EM signal would take at most, 100,000 light years (not much help, granted).
     
  10. Apr 20, 2005 #9

    ohwilleke

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    The trouble with wormholes is that the large scale structure of the universe is very close to topologically flat, as shown by the cosmic background radiation studies. A wormhole that would get you any place far away requires a universal that significantly not topologically flat.
     
  11. Apr 20, 2005 #10

    SpaceTiger

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    Except for the fact that you'd need more than a galaxy's worth of energy to achieve it. I'd say that qualifies as "can't be done".

    An interesting link on the subject:

    http://www.nasa.gov/centers/glenn/research/warp/socanwe.html
     
    Last edited: Apr 20, 2005
  12. Apr 20, 2005 #11
    Well...

    ...if you wanna get all technical... :tongue2:
     
  13. Apr 20, 2005 #12

    JesseM

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    Why do you say that? I think maybe you are taking the embedding diagrams too literally, wormholes don't require that two regions of space be "near" each other in some higher-dimensional space (in fact general relativity itself doesn't require any such higher-dimensional space for curved 3D space to be 'embedded' in).
     
  14. Apr 20, 2005 #13

    ohwilleke

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    Don't they? The idea of a wormhole is that you avoid the need to travel at greater than c to get from here to there in a given time by connecting two points via some connection of a shorter length. I have a hard time seeing how that isn't equivalent either a higher dimensional space or a topologically non-flat space.
     
  15. Apr 20, 2005 #14

    JesseM

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    What do you mean by "topologically non-flat"? I thought flatness referred only to curvature, and would be compatible with a range of topologies. For example, it's possible to have a flat universe with the topology of a torus, as discussed in this article.
     
    Last edited: Apr 20, 2005
  16. Apr 20, 2005 #15

    turbo

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    Darn! I was hoping to use my Magellen GPS receiver to find my way back. I'll be 99,970 (or so) years too old to do that. :uhh: Unless the wormhole slowed MY time down so that I perceived only a brief passage while the entire external universe experienced 100,000 years of time. That way, a powerful enough beacon in Earth orbit might help me get back...although after about 200,000 years elapsed time on Earth, "catching up with old friends" might be a bit problematic. :frown:
     
  17. Apr 20, 2005 #16

    JesseM

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    You don't need a wormhole to get to the other end of the galaxy in a short subjective time, special relativity will work fine. From the point of view of observers at rest wrt the galaxy, although it will take you over a hundred thousand years to cross it, if you go fast enough your clock will slow down enough so that you have only aged a few years when you reach the other end...from your point of view, you are aging normally but the length of the galaxy has lorentz-contracted down to much less than a hundred thousand light years. You can look at the relativistic rocket to see a table of how much onboard time it would take to reach various distant locations, like the Andromeda Galaxy, if you accelerated at 1G for the first half of the journey and then decelerated at 1G for the second half (for example, it'd take 20 years to reach the center of the galaxy, 28 years to reach the Andromeda galaxy). But like you said, when you return to earth huge amounts of time will have passed according to earth-clocks.
     
  18. Apr 21, 2005 #17

    DaveC426913

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    Yes, on average. Doesn't mean smaller areas are flat too.
     
  19. Apr 21, 2005 #18

    DaveC426913

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    You'd be wrong. That merely qualifies as "impractical". Before determining whether it is feasible, we must first determine if it is theoretically possible, which it is.
     
  20. Apr 21, 2005 #19

    SpaceTiger

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    No, it qualifies as "can't be done". You can't harness a galaxy's worth of energy to get across a galaxy. That's one of the most ridiculous things I've ever heard. At this point, we don't think it will be physically possible to perform this feat. I acknowledge that physics might change, but it simply can't be done with what we know.
     
  21. Apr 21, 2005 #20

    JesseM

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    "more than a galaxy's worth of energy" to do what, exactly? To travel across the galaxy fast enough so that the journey only takes a few years of onboard time? To build a wormhole connection from one end of the galaxy to the other? To build an Alcubierre warp drive to get you there? I don't think it's been established that any of these things would require that much energy, although we won't know whether the last two are even physically possible until we have a theory of quantum gravity.
     
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