I would also note that I have been applying, over very long (intergalactic) distances, the assumption that there is no expansion, which is clearly wrong.
Andromeda is nowhere near so far away that the expansion of the universe is important. (In fact, according to Wikipedia it’s being blueshifted, meaning that its gravitational attraction to us is winning over the expansion of space.)
Andromeda is nowhere near so far away that the expansion of the universe is important. (In fact, according to Wikipedia it’s being blueshifted, meaning that its gravitational attraction to us is winning over the expansion of space.)