Wouldn't that depend on how fast they are being expanded or carried apart?
Cause I propose that it's really not going or happening very fast (equally everywhere, etc) not on or at those scales at least... That's why I mentioned the speed of light, etc, happening equally everywhere, etc, dictating or otherwise defining everything that is all otherwise all "relative", etc, and that gravity is strong enough to keep it back or pull it back in or keep it in balance or check, etc... at those scales anyway... cause the exact speed of light, or 1 times light speed, is really not all that fast, etc, not on those scales anyway, etc, and is really quite very much slow at those scales, etc, happening equally everywhere, etc...
And not accelerating really either, just growing, etc, slowly equally everywhere, etc, with nothing and nowhere being the center, except for it's only appearing that way from where you are at, and wherever you are at, etc, and that gravity is sufficient enough or does do enough to keep it (all) (the slow expansion) (and the slow (and equal) growing (or expading) of the pockets, etc) in check, etc...
Gravity on or at those scales being able to conteract or balance it/them, or what is expanding it/them etc...?
Gravity declines with the inverse square of the distance, and the expansion of space is thought to be uniform. There will be a boundary distance where the gravitational force between two galaxies or galaxy clusters is insufficient to bind them against the expansion of space. Galaxies separated by more than this distance will be carried apart by the expansion of space.
But it's not just gravity, the area's of extreme darkness or blackness, the pockets, are all pushing out equally also, (growing at the speed of light equally everywhere I believe) anyway, pushing out against or on all the normal matter and material (clusters and strings of galaxies) (us, etc) and gravity is working or operating within those bounds and with(in) those forces as well also, etc, which is why I think we have or get the "picture" that we do, etc (the clusters and strings of galaxies, etc) (being or looking the way they are or do, etc)...?
All space is expanding uniformly (though accelerating) but not at the speed of light (you have already been corrected on that), whether illuminated or in darkness. The mass of galaxies gives them a gravitational field that holds them together despite the expansion if they are near enough to each other for gravity to dominate. That's it.
Your not taking into account that the expansion itself is being caused by the push of the dark areas or pockets, on themselves, and everything else, etc...? (and their growth, etc), (which is causing them to move through space, etc), (and everything else around them or with them or it, etc), (and that's why the expansion seems/appears to be accelerating when it's really all uniform and/or otherwise all relative, etc), (relative to them, etc), (and their rate of growth and/or expansion, etc), (which I think is at 1 times light speed, etc), (and then and only then considering gravity along with that, etc)...?
And while this example is too simple and to crude to explain absolutely everything about it, it still does a pretty good job of giving you a pretty accurate picture of what's actually going on for the most part, etc, but not exact, etc, but pretty close, etc... It lacks to explain all the littler more specific details though...
I add that so I don't have to get into long winded explanations, "etc"...
Some of those hexagons might lose some of the "stuff" or walls between them and merge together sometimes maybe, I don't know, etc, or they might be slowly moving through space (as/and/or because of their growing, etc) towards some theoretical and as of yet unseen edge or something maybe, again, I don't know, but that is some of the details that are left out in this example, etc, but otherwise you should be able to get the general picture, etc...
