Several books have indicated that the Universe was infinite at the time of the BB. This was in "Gravitation" by Misner, et al., as an excercise. This would only be true, according to Misner, with the flat and hyperbolic solutions to GR, not with the spherical solutions. What would the Universe look like at the time of the BB if it is inifinite? If it is finite, a point or little tiny ball would seem a likely shape to imagine, but an infinite BB gives me some trouble. Would it be an infinite sheet, two dimensions, no thickness? Could such a sheet be folded? Would it have to have a thickness? Or am I missing something?