Yeah i've read that book, interesting read, ive also got fabric of the cosmos, his other book, but havn't read it yet. In all honesty I didn't get on with the extra dimensions bit very well because I couldn't visualise it. I'll re-read it again and see if I get on better this time.<br /><br />I'm unsure as to whether that size would be outside the parameters, as, if the BB theory is to be believed then we came from a super dense, unimaginally small point, which would suggest that unless we became smaller than that we probably wouldn't have a problem as it wouldn't be outside the universe's parameters.<br /><br />Also, we can't exceed the speed of light, as far as we know, so we couldn't be put outside of the universe. This is almost like a natural defence to prevent this happening - mayb there is something similar with size - at a point we simply can't get any smaller - the energy requirements are too great, as it is with the speed of light.