>>>At one moment, it was believed that space curved back on itself - like the surface of a sphere, but with one more dimension. I am not sure what is the current view on this.
>>
>>(Super)string theory proposes 10 dimensions - prior to the Planck time (10**-43 seconds) all were of similar size, after that time only the 4 dimensions we are familiar with expanded, the remaining 6 remained compacted to below the Planck length (10**-34m) and consequently are not directly detectable.
>>
>>There is also M-theory (membrane), which proposes 11 dimensions.
>>
>>There was a recent theory of the creation of the universe based around parallel 4-dimensional membranes in a 5th dimension in collision, called something like the "Ekpyrotic" theory. I'll try & find a reference for you.
>
>Well, I have been doing some reading about superstrings. Only the latest paragraph you wrote is unknown to me.
>
>Hilmar.

Here's a couple of references :
http://feynman.princeton.edu/~steinh/npr/
http://www.space.com/scienceastronomy/astronomy/bigbang_alternative_010413-1.html