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Question on the expansion of space

  1. Jul 20, 2006 #1
    My apologies if this is too simplistic or poorly phrased of a question. I am trying to get a better handle on what the observed expansion of space implies about the nature of space itself.

    My basic question is: What are the mainstream theories and descriptions that cosmologists and physicists have put forward with respect to what might be occurring at the smallest dimensions of space that is undergoing expansion?

    Am I correct to think that as galaxies and clusters of galaxies recede from one another with this expansion of space, this implies that over time there is increasingly "more space” existing between / among them. If so, then where does this new “more space” emerge from? If space at the smallest dimensions involves Planck-length “quanta”, then what is the thinking about where these new “quanta” of space come from to account for the “more space” between galaxies and clusters associated with the expanding universe?

    I’ve read a little bit about quantum foam and loop quantum gravity (I do mean a little bit) but haven’t seen anything that ties those descriptions of space at these smallest dimensions to the expansion of space at the cosmological levels. Thanks in advance to those of you more versed in these things for any insights you can provide.

  2. jcsd
  3. Jul 21, 2006 #2
    One theory suggests that dark energy is a result of imperfect annihilations from the 'quantum foam'. Since the quantum foam expands with the expansion of the Universe, the larger the Universe, the greater the dark energy contribution becomes from these imperfect annihilations. In other words, the bigger space gets, the more dark energy it creates, and the more dark energy it creates, the bigger space gets, whence the Universe's acceleration. Note that just after the BB, the Universe was dominated by matter and dark energy was a tiny fraction of Omega. Today dark energy is the dominant portion of Omega (DE=0.73, Matter=0.27). Clearly, in the future, DE will increase its share of the Omega pie as space expands, and Matter will become a tiny sliver.
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