My favorite theory is that the universe is finite, some sort of (hyper)sphere or -torus. If we could just look far enough out there we would see our own galaxy
What would be even cooler is if it was warped like a moebius strip in a higher dimension, so that when we look out there, everything is mirrored from "our" reality :-D
That first theory would be interesting, but wouldn't it be basically impossible to prove unless the finite repeating universe were also pretty small? We see distant objects as they were in the past, and I'm not sure we'd recognize our own galaxy a billion years ago and a billion light years away.
It's actually an interesting thought experiment. If that theory were true, and assuming we could see ourselves face-on (rather than edge-on), then I wonder how far away and far back could we recognize ourselves.
Yeah, I realize we're looking in the past and can't "see" ourselves (probably not even our own galaxy, depending how far out we have to look). But I guess the theory in itself is not any more "weird" or "outlandish" as the idea of an infinite universe.
And maybe if we actually look both ways, we could find another galaxy that could be proven to be the same (because of some particularly remarkable stars/quasars/supernovae etc. in them). Who knows, maybe the universe is smaller than we think and we just don't recognize the "same" galaxies on different images because they are billions of years apart?
For all we know it might be - or it might actually be infinite - but the trouble is that we're limited by what we can see / detect, which is in turn limited by the speed of light.
Another commenter asked something like, what if the universe is much bigger than the observable universe, because everything beyond that 'border' has redshifted out of reach - or hasn't reached us yet / never will, because it's moving away faster than the speed of light.
That assumes that we can somehow see through time, which leads to a whole bunch of inconsistencies (aka time travel paradoxes). There's no way to look through large distances without looking back in time, unfortunately.
I don't see how seeing one's past may lead to paradoxes. Meddling withthe past would still be impossible, due to the,distance and the speed of light limit.
What am I missing?
What would be even cooler is if it was warped like a moebius strip in a higher dimension, so that when we look out there, everything is mirrored from "our" reality :-D