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The sum

  1. Sep 8, 2005 #1

    wolram

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    Of all possibilties, is infinite, if any where where will the search for qg stop ?
     
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  3. Sep 8, 2005 #2

    marcus

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    quantum gravity is simply the study of spacetime itself

    (gravity is the geometry of spacetime. "quantum" is only a word indicating our present level of understanding. the important thing is to understand gravity-----that is the geometry of spacetime---better)

    you ask, very reasonably, WHEN WILL THE STUDY OF SPACETIME and its geometry STOP?

    I will try to answer this, since it's you wolram.

    Life-forms will usually study something until they figure out how to eat it, or cook with it, or use it as a weapon.

    these generally turn out to be different kinds of burning.

    this business with gravity is a classic case, wolram.

    Lifeforms (whether human or not) will continue studying spacetime until they figure out how to burn it.

    we have a long ways to go
     
  4. Sep 8, 2005 #3

    marcus

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    didn't anybody else read Slaughterhouse Five?
     
  5. Sep 8, 2005 #4

    selfAdjoint

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    Yes, I read it twice, but I don't have your literary recall!
     
  6. Sep 8, 2005 #5

    marcus

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    you have great literary recall, I just happened to be impressed by a small anecdote in Vonnegut's S5
    where there are these advanced beings who look like brooms
    and at the top-end of each broom handle there is a hand, with an eye in the palm of the hand.

    in situations where we would want to WINK they close and open their hand several times rapidly, which has the same effect as winking.

    they are four dimensional beings who can each of them put their now-consciousness at any point along their world line and live in any part of their life they want to

    they know how the world ends
     
    Last edited: Sep 8, 2005
  7. Sep 8, 2005 #6

    marcus

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    they know how the universe ends
    This is how it ends: one of them is a test-pilot whose job is to test new flying saucers
    It is a new model fighter---with a newly developed propulsion engine, very spiffy, expected to be really hot.

    He presses the starter button and the universe ends.


    these beings are four dimensional and for them everything has already happened. the humans ask them why don't they NOT build the new saucer engine (I think it must derive power by consuming space or time, but Vonnegut does not say).
    they just look puzzled and open and close their hands very rapidly (which is how they express embarrassed laughter at a silly question). It does not occur to them to try NOT to destroy the universe because for them it has already happened.
     
  8. Sep 9, 2005 #7

    wolram

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    That question sounded rude, it was not meant to be.
    My thoughts were more like, may be qg is unsolvable without including the
    other unknowns, "what is mass", "what is energy", and that the bottom up
    method is like attempting to jump several stages of learning. clumsy uneducated
    thoughts i know.
     
  9. Sep 9, 2005 #8

    marcus

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    Hi wolram, I already answered. Maybe someone else can give you a different answer but this is the best one I can think of. (It's my own thought on the subject you raised, not actually taken out of Vonnegut's story but you might say inspired by it.)

    I think the essence of your question was when will the study of spacetime (and the curved geometry we experience as gravity) stop. I am saying that this study will probably continue until we, or whatever other species they have then, figures out how to USE it.

    consume it, harness its expansion, make more of the stuff for particular purposes, hide in it, lay eggs in it, destroy it, use it as a weapon, make art out of it, whatever life-forms USE stuff for------the particular use I would not expect anyone to be able to predict at this stage.
     
  10. Sep 9, 2005 #9

    selfAdjoint

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    Umm, I think the first question is already going away. Baryonic mass is presented in the Standard Model as an interaction, no more primary than magnetism is in EM. Now Dark Matter (nonbaryonic mass of some kind) is another question, we have no agreed-on theory of that, but if I was to make a bet, it would be that it is an interaction too.

    Energy is the ability to do work.
     
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