After reading How do we resolve a flat spacetime and the cosmological principle? I still remain perplex.
Please excuse my ignorance and try explaining to me :
I thought that basically, when we rewind back to the big bang, we get down to planck's dimension (something like 10exp-35) which is small and therefore (?) finite. (i acknowledge we have yet no theory beyond that).
big bang => small
small => finite
finite * whatever_expansion = finite
finite ~> curved (but see below point #2)
I derive :
big bang ~> should still be curved
So, just like @adam asked (see link above), how can spacetime be said to be flat now ?
May be my question simply gets down to clarify :
When experts say "flat", do they mean :
- strictly flat whatever the geometry (and then i am lost)
- strictly flat, but in the sens of specific geometry like "Flat universe ... In three dimensions, there are 10 finite closed flat 3-manifolds, of which 6 are orientable and 4 are non-orientable" as mentionned in [wikipedia Shape_of_the_Universe] (http://en.wikipedia.org/wiki/Shape_of_the_Universe)
- or : nearly flat only, as we can observe, (but can't be strictly, because ... see above my reasoning).
- other ? (please elaborate ...)