Cosmological implications from the observed properties of CMB

Observations of the cosmic microwave background represent a remarkable source of information for modern cosmology. Besides providing impressive support for the Big Bang model itself, they quantify the overall framework, or background, for the formation of large scale structure. Most exciting, however, is the potential access these observations give to the first moments of cosmic history and to the physics reigning at such exceptionally high energies, which will remain beyond the reach of the laboratory in any foreseeable future. Upcoming experiments, such as the Planck mission, thus offer a window onto the Physics of the Third Millennium. To cite this article: A. Blanchard et al., C. R. Physique 4 (2003).