Nice explanation. I see a third possibility, besides from the historical effect of something now outside the observable universe because of inflation, or from the current effect of dark matter inside the visible universe. If a huge mass of ordinary matter were hiding in the un-ionized region just within the observable universe, but outside the visible universe, it could effect the motion of visible objects through gravity, even though any light it produced would be blocked by the curtain of atoms and molecules that shrouds the origin (real or apparent, depending on your world view) of time from sight.
Slashdot Mirror
Nice explanation. I see a third possibility, besides from the historical effect of something now outside the observable universe because of inflation, or from the current effect of dark matter inside the visible universe. If a huge mass of ordinary matter were hiding in the un-ionized region just within the observable universe, but outside the visible universe, it could effect the motion of visible objects through gravity, even though any light it produced would be blocked by the curtain of atoms and molecules that shrouds the origin (real or apparent, depending on your world view) of time from sight.