“No matter what technique you use, you should get the same value for the expansion rate of the universe today.” -Ben Hoscheit
Is it possible to measure the Hubble constant using supernovae or a Cepheid variables from galaxies outside the KBC void? I take it that the HST’s various methods of measuring the constant have had to rely on supernovas/Cepheids from less than a billion light years away, placing them inside the KBC void and thus subject to extra gravitational pull from matter at the edges of our void. What’s the distance record for a supernova/Cepheid observation to establish the Hubble constant? I take it such measurements might be more in line with the Hubble constant we measure from the CMB.
The difference in expansion at at different distances is one of the ways the look at what dark energy is doing. So if we naively took a close in expansion rate that is off, we would get the rate of change of the expansion rate wrong. What does this new knowledge do to our understanding of how the expansion rate changes over time?
Is "average" density defined via random sampling of galaxies (observers) or random sampling of points in the universe? Since more galaxies, by definition, appear in more crowded parts of the universe, sampling by selecting a galaxy will give a much greater average density than sampling by selecting a random point of the universe. Which kind of average are we less than?
Our solar system is in a relative void too: the outskirts of a spiral galaxy. between arms. Antropic principle maybe selects for voids to support life because of lower radiation levels?