> I think it's established fact that energy and matter are, and that time is finite in the past, so the visible universe is finite. None of that is established

> I think it's established fact that energy and matter are, and that time is finite in the past, so the visible universe is finite. None of that is established, actually: Metric expansion of space comes with a cosmic event horizon where redshift goes to infinity. While the energy contained within that region is finite, there's no reason to assume that the universe outside the horizon looks any different than inside the horizon, and it might very well be spatially infinite. As to time being finite in the past, it is possible to generalize Einstein's equations so that they can be extended past the big bang singularity, and what you get is a mirror universe on the other side. The issue here is that as we approach Planck scale, quantum gravity becomes relevant, and we have no predictive theory of that.