I am just stating the obvious--Yes, humans "work" with infinities as Limits or as constructs that make an equation valid, but these concepts of Infinity are strictly theoretical, or "constructed" by acclamation, to make the mathematics work. We are no more sure of Infinity on a physical level...
And your statement is again, a "thought experiment" -- probably stated as correctly as we 4-space humans can do, but nevertheless like saying "magic occurred". The problem lies in not being able to grasp the REAL reality of how our Universe works (I can't even say "came to be", since infinity...
Well, Andromeda (and A LOT of other objects) is blue-shifted and supposedly moving TOWARDS us, so your statement is unfounded at the start.
Also, your statement's conclusion is a non-sequitur--if everything was moving away from us, one could *logically* draw the inference that we ARE at the...