your round earth assumes things about gravity that are unproven. Newton's gravity is the law, einsteins is a weak theory.
If the world would be on infinite loop, it's not much more of a stretch to picture the stars and sky on the same loop.
Pacman theory works by suggesting that there is something that moves from one edge of the 'screen' to the other. We're obviously able to see right through it, or we'd be wondering what it is. I don't mean to presume what the something is, but many suggest it's of supernatural origin and above our level of understanding.
Oh don't fuck with the stein.
YOu see Newton was a one shit wonder. What he managed to do was pull some theories out of his ass, and half of them were true. (side note: you realize his laws accept that the earth is a ball in space? Yeah, that was his Laws) But what he couldn't do was explain how gravity worked. His funamental flaw was that he believed (as I'm sure you do) that gravity is instantaneous.
This is where my main man, Albert comes in. You see he took a look at all of Newton's work. All of Newtons's math and said, "wait! This shit ain't right!" How can Gravity be instaneous if light ain't even instaneous!" In fact it takes 8 minutes for light to travel the 149,600,000 km from the sun to the earth. And since nothing can travel faster than light, well damn, we got ourselves a conundrum... unless gravity isn't instaneous. Hey, what if it travels AT the speed of light?
In fact my friends, that's what it does. Think of space as a two-dimensional bedsheet. Or even better, a trampoline. When you place an object on this trampoline, it puckers, or warps und it's massive size. Think of the sun as a bowling ball, and the earth as a golf ball (obviously sizes aren't acrurate, the earth should be slighlt smaller than a pinhead). If you roll the golf ball, on a perfect tangent to the sun, it will, in fact, roll along the sun's gravitational warping as well as the earth does. Unfortunately, the size of the area in which you can do that is much too small, friction is much too great, and who wants to spend that much time working on their putt?
But in space, things are MUCH larger. It becomes much easier to put something in orbit, with a margin od spave millions of miles wide! WOOHOO!
Anyway. The original point was the speed of gravity. It is equal to the speed of light. 227,000 kilometres per second. Now, imagine if the sun just DISAPPEARED! AHHHHH! WE"RE ALL DOOMED! Well, acording to Newton, yes we are. we'd have no time to get off this world. Gravity would imeadeatly let go of us, and we'd fly off into space on a tangent of or final curve the instant the disaster took place. Be we know this just can't happen. Einstein already figured that one out. How could we be released from orbit before we saw the resulting light of the destruction?
So in we know understand that we have 8 minutes to get off the earth. Aw hell, we're still proper fucked. But it makes for a smashing end, don't it?
So we see that Newton was a fucking poser, and Einstein pwned him proper good!