THE SCIENTIFIC OBJECTIVES

The main objective of PLANCK mission is to answer cosmology key question by determining the geometry and content of the Universe, and to answer the question: which theories describing the birth and evolution of the Universe are right? Planck will observe the primary fluctuations of the Cosmic Microwave Background (CMB) emitted 13 billion years ago, 400 000 years after the Big Bang. Nowaday, the CMB pervades the Universe and appears as the radiation of a black body at 2,726K. The fine measurement of the anisotropies or the infinitesimal variations of temperature around this mean value, gives rich information on the properties of the Universe at its birth.

Planck will supply maps of these temperature and polarization anisotropies of the CMB with an angular resolution lower than 5 arcmin, and a temperature sensibility of a few microkelvins on the whole sky. Planck large frequencies cover (30-857 GHz) was chosen to supply detailed results on the galactic emission (significant for the study of the polarization) and to study galaxies clouds (through the Sunyaev-Zel'dovich effect).