My view of space is that its two qualities are infinity and equilibrium.

What fills space is this "energy." Which manifests waves/patterns.

The energy radiates out, toward infinity, while the patterns coalesce in, toward equilibrium, essentially synchronization. One wave is more efficient that lots of smaller waves.

So there are galaxies. The structure coalesces in and whatever residual energy it carries, is shot out the poles as quasars. Which as essentially giant lasers, are synchronized light waves.

Energy being lost in one area is replaced by energy radiating in from surrounding areas. Which has an harmonizing effect across the universe. Black body radiation.

So both are entropic, but as giant feedback loops, it functions eternally.

The "missing mass" is due to the properties of mass being intermediate effects of this relationship, so the synchronizing effect goes from the barest bending of the light, to the vortices at the center of galaxies. Essentially mass is an effect of gravity, not gravity a property of mass.

The music is more real than the matter.