*thinks about it* *head hurts* Many immediate thoughts: The main problem is that gravity is a pathetic, and I mean pathetic, and I mean, pathetic force. As evident by the fact that you awesome, glistering and electrochemically driven muscles have no problem fighting a planet's mass worth of one. And the universe is huge, way beyond such a topology begins to matter. As in very huge. Huger than you think. In fact, by reading this sentence you probably thought of something huge so I'd like to stop you and tell you are wrong. It's even huger than that. Such a gravity effect would be way, way, way smaller than being affected by the gravity of a paperclip in alpha centauri. Or a dandelion in andromeda, all of which are relatively "close by" compared to the distances you describe. Now. Were the universe infinite in detail, I suppose you could have infinitely small effects, however another problem is that the universe isn't. There is a "distance", under which details smaller than it are "meaningless" called plank length or so the even science-industrial complex says. Things now get super complicated regarding quantum gravity but, intuitively talking, I am rather sure that at some point any such "space curvature" or whatever you describe gravity in, at so far a distance, would need to be described in detal smaller than a plank lenght's worth. And so become "meaningless". It would be like trying to talk about an energy state lower than vaccum energy (which is also defined by the plank constant). Plank lenght, is basically like a hard coded limit where the simulation's detail ends Another problem is that there is a difference between the observable universe, and the "universe". The observable universe is only the one which light speed interactions had a time to reach us (and in turn ours effect it), but I am rather sure that the universe is assumed to be much larger than that and because of space's expansion, parts of it will never become observable because light cannot catch up from point A to point B, due to all that expanding space inbetween. Since I am also rather sure than gravitational effects propagate at the speed of light (otherwise merely waving a rock around, would mean FTL communication with a sensitive enough detector somewhere else), this mean's sun's gravity hasn't had the time to reach the "edge" of the universe in order to "loop around", neither it ever will. To sum up: No