Doesn't time slow down as you move away from the Earth?
time is weird. And scientists still cannot explain why time can pass quicker or slower at some points than at others, but it can. There are a few theories which I won't go into here. Anyway we have to keep in mind this is a turn based game, so it wouldn't make sense(or be fair, especially in multi-player) if one players turn becomes the equivalent of two turns for another player located in a different sector of the universe. I know that wasn't suggested, but my point is that you can go too far with realism.