>>12637580Nobody knows, but it's likely a similar phenomenon to
>If atoms are mostly empty space, how come solid objects don't phase through each other?The answer to that one is, allegedly, the Coulomb barriers generated by electron clouds around atoms. Or, briefly, the EM force.
My hypothesis for your situation is that gravitational strength is highly correlated with temperature in the medium. Within galaxies, the gravitational pull is influenced by stars and planets. Whereas outside of galaxies the gravitational pull is influenced by galaxies on a whole.
