tardis said:Many books and threads state that the 7 other dimensions are really small. For the 11D model to work, how small could the other 4 (x,y,z,t) theoretically/mathematically be for a stable universe model?
Then the question is how small could the visibile dimensions be in the big bang. The classical answer is zero - a singularity. But some quantum cosmologies show no singularity, but a minimum around Planck length for the spatial dimensions and Planck time for the time.tardis said:Is that really true? It seems as if t was 1 year less last year and x,y,z (the observable or known universe) some percent of a light year smaller. So the 4Ds would seem to be possible at a size less than it is today in the 11D model. I was wondering whether there was a mathematical/theoretical limit as to how small one could make x,y,z & t and still have an 11D model that is possible. Is there some size (on the small side) for x,y,z & t at which the 11D model would not be possible?