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Aether Theories

  1. Dec 17, 2012 #1
    No, I'm not talking about the original luminiferous aether disproven by the Michelson-Morley experiments. I'm asking what the consensus is on whether 'empty' space is actually made of something:

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

    To what extent is there a consensus on what space is made of? On what issues are there disagreement? Which theories are the favored candidates for further development and investigation?
     
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  3. Dec 17, 2012 #2

    Chronos

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    'Empty' space is filled with virtual particles that pop in and out of existence quicker than Santa down a chimney. Some people might think empty space is comprised of these virtual particles, but, most would say they are just expressing the joy of being quantum mechanical.
     
  4. Dec 18, 2012 #3
    How can we move beyond mere speculation of what empty space is comprised of, and actually prove it definitively? Have any experimental ideas been proposed?

    When the original luminiferous aether debate was going on, it was Michelson and Morley who came up with their famous landmark experiment which settled the debate.

    How can we come up with the equivalent of a "new Michelson-Morley experiment" which could likewise settle what space is made of, so that debate and conjecture can be turned into accepted theory?
     
  5. Dec 18, 2012 #4

    Chronos

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    ok, what are you suggesting?
     
  6. Dec 18, 2012 #5

    Chalnoth

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    This question basically boils down to the nature of quantum gravity. So to answer the question, we need to have an answer to the question of what theory of quantum gravity is the correct one. There are two possible experimental avenues for this:
    1. Use detailed tests of gravity to discover where General Relativity starts to break down.
    2. Carefully examine high-energy physics in an attempt to discover the correct theory of high-energy physics, which at high enough energies must eventually also give us quantum gravity.

    The primary difficulty is that the extreme weakness of gravity compared to other forces makes both of these prospects difficult to practically impossible. It is entirely conceivable that we may never experimentally determine the correct theory of quantum gravity.
     
  7. Dec 18, 2012 #6
    In order of precedence, what further breakthroughs would help us to determine the answer?

    Are there any other lesser discoveries/advancements which could occur, which would take us forward in being able to answer the question?
     
  8. Dec 19, 2012 #7

    Chalnoth

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    I think the difficulty is that which discoveries will get us there depends upon the nature of reality in the first place. So we won't know until we have made the discoveries.
     
  9. Dec 19, 2012 #8
    Hmm, well are there any promising candidates that might help to narrow down the choices? It's hard to believe that the field is totally wide open to absolutely any explanation or speculation.

    I remember there was Stephen Lamoreaux's famous experiment which measured the Casimir force exerted by empty space. I also remember some nano-devices demonstrated at UCLA Riverside which showed how it was possible to make a sort of spring-like device supported by the Casimir force of empty space.
    There have also been experiments showing that the value of c can be altered within a QED cavity.
    I've also read about "atom lasers" which could be made very sensitive to the detection of gravitational forces.

    It seems to me that these types of experiments are gradually exposing the nature of the vacuum more and more. Nobody knows if there are any planned experiments of significance on the horizon?
     
  10. Dec 20, 2012 #9
    Lol, I'm assuming that's a reference to the fact that, to visit every household on Earth which celebrates christmas, he'd have to travel unrealistically fast?

    Anyway, I don't think this really qualifies, but I'm surprised dark matter hasn't been brought into this discussion.
     
  11. Dec 20, 2012 #10
    I'm not. Dark matter is just as elusive as any theory where our observational evidence is indirect or incomplete.

    I'm wondering if there is any progress in examining the fundamental particles. Can we show evidence of fractional electron energy, or are there any indications that quarks with fractions of e are as deep as we can go into the composition of particles. Do quarks have internal composition that determines their 1/3, 2/3, positive charge negative charge? Something must differentiate them.

    Are there any clues in the newest models of the atoms with electron orbitals, and with the theory that accelerated particles radiate within atoms and molecules, which should allow detection. Are we able to explain all of the fields and charges within the atoms and molecules or it is all theory at this point?
     
  12. Dec 20, 2012 #11

    Chalnoth

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    Well, this thread is about space-time. Dark matter would be a different topic.
     
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