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Homework Help: SciFi short story

  1. Sep 22, 2005 #1
    Hello folks. The hinge for a story I am writing is based on a theory that I can't back. It's not entirely original, but bear with me. With this machine, you could recreate any combination of energy that has ever existed - and therefore any object/being.

    The only thing I have going for me at the moment is conservation of energy. After that, I'm lost. I don't need too much, just some fluff to give my physicist some credibility. This is, after all, a short story. Any pointers? Any ideas that would make the machine more credible/believable?

    Thanks in advance,
    Yossarian Lives
    Last edited: Sep 22, 2005
  2. jcsd
  3. Sep 22, 2005 #2
    Hi. What do you mean 'recreate any combination of energy'? Recreate from what? You referenced the conservation of energy, so what energy is input to this machine?

    You might want to look at the laws of thermodynamics to highlight problems your characters' machine might have.

    1. You cannot get more energy out than you put in.
    2. You cannot change the state of a system with 100% efficiency.

    This machine will be greatly reducing the entropy of the system that becomes the recreated object, so must be drastically increasing entropy elsewhere. In the long run, your machine will actually destroy more than it recreates.
  4. Sep 22, 2005 #3
    Also, the pertinent conservation law for the operation of your machine is the conservation of information, that is, from the moment the object you're trying to recreate was destroyed, none of the information about it when it existed is lost. However, this information will almost certainly be spread out across the cross-section of its future light cone (from the moment of its original destruction) at the time of recreation. Even if your machine had the capacity to rebuild the object from this information, it still could not be everywhere within the light cone at the point of reconstruction to access all of this information. In AI they got around this by inventing a postulate that the fabric of spacetime itself stores information of everything that ever happened at every point. A similar idea may be required for your machine to work.
  5. Sep 22, 2005 #4
    Thanks a million! I think that's just enough information to weave my way through.

    Yossarian Lives
  6. Sep 22, 2005 #5


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    What's the AI here? A book? Or movie?
  7. Sep 23, 2005 #6
    It's a rather dull movie from Spielberg who inherited a treatment by Kubrick based on a short story by [not sure I'm correctly remembering his name, but...] Brian Aldiss? Or something. He's famous - I'm just ignorant. Anyway, the robots in the film do the same thing that Yossarian wants his machine to do.
  8. Sep 23, 2005 #7


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    Oh, AI the movie! I have even seen it meself yet failed to make the connection.
  9. Sep 23, 2005 #8
    No fault of your own; it was forgettable stuff.
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