What would cause it to do that? Only thing I can think of is gravity, no? That would imply there’s something in the middle that keeps everything from straying too far?
Or do you simply mean that our perception of space is limited and we simply can’t perceive it properly and thus we’d go in one direction and end up back where we started? But if that’s the case, it means we’ve also misunderstood light? Doesn’t it go infinitely? So shouldn’t there be a light source that reaches us from different directions?
Only thing I can think of is gravity, no?
They’re not talking about the stuff in the universe being finite. The space itself could be finite, for example by looping back on itself. Tthe usual comparison is to a circular track - you can drive as far as you like on it without hitting an edge, but you’ll eventually come back to the point where you started. Now scale this up to three dimensions.
That would imply there’s something in the middle that keeps everything from straying too far?
Even if we’re talking about a system held together by gravity, it does not need a central mass. The overall system just needs to be dense enough that each piece is stabilised by all the others.