One often hears that our universe is expanding because "space itself is expanding" (usually with the analogy of raisins in a cake to illustrate that this is happening everywhere and not from some central point). Can this be wholly true if measurement of space is relative to the observer?
Expansion (dark energy aside) is often explained as the inertia following the inflationary epoch. Inflation, for all its false vacuums and negative pressure, seems to be a repulsive force between particles rather than something expanding "space itself" whatever that may be. Is space itself expanding or merely distances between objects? Something must be happening in space itself to lead to CMB stretching into microwaves.
Feel like I'm missing the big picture.
A secondary query, what does it mean to move or recede relative to CMB? CMB is everywhere and in all directions, correct? How does a galaxy recede relative to a field that is everywhere? Relative to a particular photon at a specific point in space and time?