The expanding Universe and Galactic collisions

Maybe not the best way to motivate people to address your questions?--Percy

Yes, the rate of expansion is increasing, and no, gravity is not more powerful than expansion, except within regions no larger than local galactic groups.--Percy

When you said, "Gravity is massively more powerful than expansion," combined with your doubt that accelerating expansion has become accepted within mainstream cosmological circles, it sounded like an argument that the expansion would one day slow and reverse. It sounds like that's not what you were trying to say.Maybe one of the cosmology buffs will check in and help us out here, but for my part I question the validity of likening the expansion of the universe (which is only postulated to be due to the effects of dark energy, not verified) to a force and then comparing it with the force of gravity, but perhaps it's just a preference for a different explanatory model that's at work in my mind.--Percy