Wilkinson Microwave Anisotropy Probe data and the curvature of space

Inter alia, the high-precision Wilkinson Microwave Anisotropy Probe (WMAP) data on cosmic background radiation marginally indicate that the Universe has positively curved (and hence spherical) spatial sections. In this Letter, we take this data seriously and consider some of the consequences for the background dynamics. In particular, we show that this implies a limit to the number of e-foldings that could have taken place in the inflationary epoch; however, this limit is consistent with some inflationary models that solve all the usual cosmological problems and that are consistent with standard structure formation theory.