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B KBC Void

  1. Jun 20, 2017 #1
    Is the experimental evidence pointing to the fact that we inhabit a supervoid sufficiently strong? In case it were a likely scenario, could this fact have any effect on the consensus value of the Hubble parameter at present time? And on the acceleration parameter?

    The reasons behind these crazy questions are:

    Could the local (in our supervoid) Cepheid I standard candels have a significant redshift due to a weak local gravitational pull inside the void and a strong one outside it? Could this non-expansion related redshifts be significant and introduce errors in the measurement of more distant galaxies redshifts?
  2. jcsd
  3. Jun 20, 2017 #2


    Staff: Mentor

    This is an open area of research, so your questions are premature. We don't know for sure yet how much of a "supervoid" we are in, or what the effects of one, if we are in one, are on our observations.

    If we are in a "supervoid", that does not mean that whatever effects that has on observed redshifts are "non-expansion related". What you are calling a "lower local gravitational pull" is just a lower average density of matter, which, heuristically, affects the local "expansion rate" (it's more complicated than that, and as above, we don't fully understand yet how all this works, hence the "heuristically").
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