Data from the Wilkinson Microwave Anisotropy Probe (WMAP, measuring CMB anisotropies) combined with that from the Sloan Digital Sky Survey and observations of type-Ia supernovae constrain Ω 0 to be 1 within 1%. In other words, the term |Ω − 1| is currently less than 0.01, and therefore must have been less than 10 at the Planck era. The cosmological parameters measured by Planck spacecraft mission reaffirmed previous results by WMAP.