Originally Posted by Ken G

When you look at the galaxies in the "Hubble deep field", you see galaxies that are generally closer together than galaxies are now. If you look even farther, there is not much to see but quasars, and I don't know what can be said about the density of them because there is also the important effect of how they "turn on" as they form and "turn off" as they age. Eventually you can see the cosmic background radiation formed at the epoch of "recombination", almost 400,000 years after the beginning. The density then was indeed much higher than it is today. You cannot see any farther back than that, so you can't see the higher densities at even earlier times. Dark energy and acceleration doesn't do much to these observations-- you are seeing a time when such acceleration was not occuring because the effect of dark energy was comparatively weak then. You do see the acceleration we have undergone in recent years, but that shows up as an increase in the redshift we see, and does not affect the densities we infer when we have independent distance or density indicators.