"In the past few years the search for a consistent quantum theory of gravity and the quest for a unification of gravity with other forces have led to a great deal of interest in theories with extra spatial dimensions. These extra spatial dimensions are unseen because they are compact and small, presumably with typical dimensions of the Planck length, lPl = 1.616 × 10-33 cm. If the “internal” dimensions are static and small compared to the large “external” dimensions the only role they would play in the dynamics of the expansion of the Universe is in determining the structure of the physical laws. However, if the big bang is extrapolated back to the Planck time, then the characteristic size of both internal and external dimensions were the same, and the internal dimensions may have had a more direct role in the dynamics of the evolution of the Universe."