> I was hoping for some elaboration. If you mean elaboration on how the expansion of the universe works, I can give that, but as I've said, it's irrelevant to

> I was hoping for some elaboration. If you mean elaboration on how the expansion of the universe works, I can give that, but as I've said, it's irrelevant to this discussion. > At least part of the discussion is about gravity being (caused by? understood as?) the curvature of spacetime. More precisely, the curvature of spacetime around an isolated gravitating body. Which is a very different spacetime geometry from the spacetime geometry of the universe as a whole, which is what cosmologists use to account for the observations that lead us to say that the universe is expanding. > Why would matter curve spacetime, if not for the accelerated expansion of spacetime You have it backwards. What you are calling "the accelerated expansion of spacetime" is an effect of spacetime curvature, not a cause of it. Plus, as I said above, that spacetime curvature is the curvature of the universe as a whole, which is very different from the curvature around an isolated gravitating body, that we are discussing here. > matter resisting acceleration due to inertia? This has nothing to do with spacetime curvature at all. It would be present even if spacetime were flat.