On cosmic voids

Void space time is as far up any gravity wells and is aging faster than
the rest of the universe, no? And the difference in aging rates would
increase as the voids got bigger, no?

If so, could that explain the apparent increase in the expansion rate we
see today?

[[Mod. note --
1. I apologise for the delay in processing this article, which the author
originally submitted on 12 November 2015.
2. I think the amount of time dialation difference between a cosmic void
and even the densest supercluster would be very small, probably on the
order of 1%. (You can see this because the velocity dispersion of
even a dense supercluster is still at most a few 1000 km/sec, i.e.,
it's under 1% of the speed of light.)
3. The accelerating expansion is seen (even) after averaging over large
volumes of spacetime (i.e., both voids and dense regions), so I don't
think cosmic-void time dialation is relevant.
-- jt]]

In article , David Staup
writes:

Void space time is as far up any gravity wells and is aging faster than
the rest of the universe, no? And the difference in aging rates would
increase as the voids got bigger, no?

If so, could that explain the apparent increase in the expansion rate we
see today?

[[Mod. note --
2. I think the amount of time dialation difference between a cosmic void
and even the densest supercluster would be very small, probably on the
order of 1%. (You can see this because the velocity dispersion of
even a dense supercluster is still at most a few 1000 km/sec, i.e.,
it's under 1% of the speed of light.)
3. The accelerating expansion is seen (even) after averaging over large
volumes of spacetime (i.e., both voids and dense regions), so I don't
think cosmic-void time dialation is relevant.
-- jt]]

The moderator's comments are all true. There have been proposals to
explain what is usually interpreted as accelerated expansion due to a
cosmological constant by invoking some "local" underdensity, much larger
than a conventional void, but a) this doesn't seem to work in detail, is
ad-hoc, and violates the Copernican Principle (since we would have to be
at the centre of such an underdense region). Nevertheless, such
inhomogeneities need to be taken into account when interpreting
cosmological observations, since local inhomogeneities affect the
propagation of light, even if the overall expansion of the universe is
the same, and essentially all our observations are via light. Also, it
might be that local inhomogeneities "react back" and affect the
expansion rate. Very probably not enough to explain any cosmological
observation, but might need to be taken into account when doing
cosmology at the per-cent level.