Remaining Mysteries CMB observations fit LCDM standard cosmological model but leave three major questions unanswered: Why is the CMB so uniform? (almost exactly the same temperature in opposite directions) Why is the Universe flat? (zero spatial curvature) Why were the initial conditions scale invariant? (equal number of lumps of all sizes) The theory of Inflation appears to offer a "natural" explanation for all of these ...and also makes prediction that there is a background of primordial gravity waves ...which will generate B-mode CMB polarization with a specific form