I have read that gravitation in a homogenous scale of the universe should cause expansion to decelerate. However, that seems to be the opposite of my logical conclusion.
It seems that if spacetime expands then the large scale affect of gravity in that space time volume would be decreased. So stepwise, less gravitational pull would be exerted allowing expansion to increase (or the perception of accelerating expansion).
I would compare this to escape velocity - if something reaches escape velocity - the affect of gravity exerted by those bodies will continually reduce and thus they will accelerate from each other (though admittedly at a lesser and lesser change in acceleration as their distance increases.) [Edit: This part is incorrect as pointed out below]
So why is there a need for dark energy: As everything moves farther apart it, the overall pull would further reduce allowing everything to move apart at an accelerating rate. No need for an exotic dark energy force - just the logical consequence of space time curvature spreading out.
So can anyone explain why it is often stated that “as the universe expands gravity should slow down the expansion.”
Is there something I am missing?