(April 4, 2014 at 1:57 pm)Fromper Wrote: I had assumed we couldn't look back at our own galaxy at an earlier time, because the rate of expansion of the universe has to be slower than light
This does not appear to be the case - beyond about 4.5Gpc distance, the expansion rate exceeds the speed of light. (4.5Gpc is ~1.47e10 light years)
(April 4, 2014 at 1:57 pm)Fromper Wrote: But the idea that the curvature of the universe would allow us to look back at our own galaxy from the opposite direction of the one we took to get here during universal expansion hadn't occurred to me. But if that were the case, wouldn't that make the universe smaller than expected, since we'd be seeing the same part of space when looking really far away in two opposite directions?
As Alex pointed out, this possibility has been observationally ruled out. The lower possible bound on any curvature of spacetime is too large.
