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The Galactic Barrier

  1. Feb 14, 2007 #1
    Off course we should not take too seriously what we read in Sci Fi books. I've just been to lazy to do any research into the concept of a galactic barrier which was introduced to me in a trilogy of books called the 'Q Continium' by Greg Cox. So if anyone knows if such a barrier does exist then please let me know.
     
  2. jcsd
  3. Feb 14, 2007 #2
    Probably not
     
  4. Feb 14, 2007 #3
    As a rule, assume that Star Trek gets anything related to science wrong.
     
  5. Feb 14, 2007 #4

    DaveC426913

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    They tried this in one of the movies and in the TV show. It was nonsense there too.
     
  6. Feb 14, 2007 #5
    Care to explain what this galactic barrier supposed to mean in science fiction? :tongue:
     
  7. Feb 15, 2007 #6

    Kurdt

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    Its a barrier of energy at the edge of the galaxy. There is also one around the centre of the galaxy. Its a fictional creation of Star Trek.
     
  8. Feb 15, 2007 #7
    Yeah.. but if you are just looking for a wacky energy barrier justified by physics, you could google the "Domain wall"

    http://en.wikipedia.org/wiki/Domain_wall

    http://www.damtp.cam.ac.uk/user/gr/public/cs_top.html#walls

    I think roughly it is when you have a phase transition such as water turning to ice, crystals that form adjacent to each other lock into a particular ordered structure, but crystals that form far apart cannot do this, so when the crystals grow to the point that they meet there is going to be a flaw in the crystal.

    Apparently there is an analogy with the fundamental forces that separated out when the universe had cooled enough.. stuff nearby snapped into one configuration but stuff to far away to communicate might have snapped into another.

    I dont really know what I am talking about but the upshot is there might be walls in space (but we havent seen them) that separate one patch of physics from another with a huge gravitational force
     
  9. Feb 15, 2007 #8

    DaveC426913

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    Well... in science fiction what it's supposed to mean is a plot vehicle to provide tension. In the real world, it is nonsense.
     
  10. Feb 15, 2007 #9

    DaveC426913

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    Sounds a lot like a black hole to me.

    I think if there were a barrier between parts of space that were fundamentally different, it wouldn't be a "wall" with a length and width (because that means the space on the other side has the same lengths and widths), I think the barrier would be much more elusive, for example it might be a barrier in apparent size. We might have to shrink ourselves down to smaller than the Planck length to gain access.
     
  11. Feb 15, 2007 #10
    Or even cosmological "domain walls" as postulated in some exotic theories. Well, anything that splits up the universe into cells would do I'd think. M-theory's "Horava-Witten domain walls" might fit the description too but I don't know ANYTHING about it :) But none of what I'm saying has been verified, and certainly none discovered that "surrounds" our galaxy... so it's pure fiction as far as we can tell so far.
     
  12. Feb 15, 2007 #11

    hellfire

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  13. Feb 15, 2007 #12
    Now if only there was a pedagogical introduction to "Horava-Witten domain walls" for non-string theorists :) They sound impressive enough. It would be really cool if we could get Witten himself to show up and explain it to us/me. Hmm, I wonder, does he know about the existance of PF?
     
  14. Feb 15, 2007 #13
    If there were a galactic barriercould someone travel beyound this? What would one find and experience at the end of the galaxy IYO.
     
  15. Feb 15, 2007 #14
    Ummm, I don't think anyone can really answer that.

    The start of the rest of the universe, I'd presume.
     
  16. Feb 15, 2007 #15

    DaveC426913

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    Ghosts, faeries, Santa Claus.

    When you apply 'what if's to what is a wild speculation in the first place, you fling the door wide to whatever fantasy you ... fancy.
     
  17. Feb 15, 2007 #16
    Consider a hypothetical spaceship capable of warp drive going on an inter-galatic mission. Would this hypothetical spaceship have a problem with the graviational force of the entire Milky Way when leaving our galaxy?
     
  18. Feb 15, 2007 #17
    What do you mean by "warp drive", hypothetically?
     
  19. Feb 15, 2007 #18
    Hey, don't tease, Yenchin!
    McHeathen, that really is too hypothetical to answer. Speculations on warp drives usually already contain a series of practical impossibilities.

    certainly the gravitational force of the galaxy is not that extreme from our point of view. The force of earth is greater when standing on earth (obviously) and normal matter certainly passes through galaxies without any problems, for example when galaxies collide.

    here is an interesting link:
    http://en.wikipedia.org/wiki/Alcubierre_drive
     
  20. Feb 15, 2007 #19

    DaveC426913

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    It's not hypothetical - the spacecraft's motor is irrelevant. All that matters is the gravity well and the craft's velocity/acceleration.

    It simply comes down to: what is the escape velocity of the galaxy? Apparently, according to Wiki, it is about 1000km/s, whereas the current velocity of the solar system in its orbit is about 220km/s. So, if a craft wanted to coast out of the galaxy, it would need to gather an additional 780km/s before shutting off its engines.


    Note: I talk about coasting because escape velocities are only meaningful if we have to worry about running out of fuel. If a spacecraft is able to run its engines continuously, then escape velocity is moot. (this is true whether escaping the galaxy - or Earth). Under constant thrust, a spacecraft will get away from a gravity well simply with persistence.
     
    Last edited: Feb 15, 2007
  21. Feb 16, 2007 #20
    We are talking about a drive that circumvents one of the most fundamental laws of physics. You can probably fly out of a black hole or backwards in time with this thing. Who is to say the concept of escape velocity or even conservation of energy or momentum is still relevant?
     
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