Cosmic expansion drives galactic dynamics

The cosmic acceleration scale cH and the extra-Newtonian acceleration inferred from galaxy rotation and velocity dispersion are on the same order of magnitude, 10^(-10) ms^(-2), but opposite in direction—thus often disregarded as a numerical coincidence.

However, the correspondence becomes natural when the vacuum is viewed not as an empty void but a physical, relativistic continuum in flux. Much like in hydrodynamics, an outflow of spatial substance from a local system into expanding, sparser surroundings pulls bodies together, whereas inflow from denser sources pushes them apart.

The universal field arising from the immense efflux of space expanding isotropically cannot be canceled by the shell theorem—which strictly holds for stationary rather than dispersing matter—nor curtailed by distance, as the quadratic rise in galaxy count outweighs the inverse falloff of individual potentials.

By partitioning the universal flux into local and cosmic components, we derive the generalized baryonic Faber--Jackson and Tully--Fisher relations, matching observations without dark matter or modified gravity. Accordingly, structures emerge on ever larger scales as the turnaround radii of efflux--influx balance lengthen with the thinning cosmic density from the early universe to the present sparseness, manifested in the cosmic gravitational redshift.