Also, Psnarf, you have out Psnarfed yourself.
We aim to interest, elevate, and/or amuse. I was worried that some of the references were somewhat obtuse. There exists people who have never watched an episode of "Star Trek - Deep Space Nine" so they wouldn't know that "Quark" is the name of the Ferengi who runs the bar and holodecks. I didn't properly cite the panel taken from a Dilbert cartoon. I appreciate your positive remarks.
I saw a NOVA episode (youtube?) that depicted the Big Bang putting forth the proposition that the earliest rate of expansion was faster than light. I wonder what slowed it down, or if the surface containing the universe is still expanding faster than light. I imagine that it would have to because what happens when the light from the earliest stars and galaxies (Hubble Deep field, for example) reaches the edge? We can never know the nature of the edge of the Universe, so it's just a thought experiment. Would the photons reflect/refract, get absorbed, pass through into that which does not exist? Someone speculated that at the quantum level, a photon exists everywhere until an observation collapses the everywhere photon into a point. The earliest galaxies we can detect are also sending photons in the opposite direction, where they would never be detected, unless they reflected off the boundary.
Sound propagates as a pressure wave. The black-box microwave radiation is everywhere, there is no surface to be affected by the pressure waves.
Gravity lensing is observed beyond the edges of the galaxy containing the super-massive black hole. If the lensing occurs via photon refraction passing through a denser region of space-time with a curved shape with a maximum at the center of the galaxy tapering off beyond the visible region '()' then perhaps we have underestimated the gravitational influence of the central black hole? If that is the case, we wouldn't need dark stuff to explain why a galaxies don't fly apart. I need to cogitate the matter more deeply before I can explain to myself what the heck I'm talking about, this nonsense of space-time density forming a convergent (plano-convex) lens around a galaxy.