Planck
is an ESA mediumsized mission devoted to study in detail the Cosmic
Microwave Background radiation. Although the universe is in a quite
inhomogeneous state today, it originates from a much smoother
configuration that progressively became more and more irregular as
gravitational instability developped. Since the CMB essentially shows
a picture of the matter distribution at an early epoch (370,000 years
after BBN), the temperature fluctuations it contains are extremely
small and hence difficult to measure accurately.
I will shortly review some historical aspects of CMB studies, and then
focus on the main steps of the Planck data analysis that allow to go
time ordered data to frequency maps, component separated maps and
finally cosmological parameter estimation.
The subteltites of how parameters are estimated (rather than measured)
will be presented, as well as the status of the now canonical
"corcordance model", i.e. the six parameter cosmological model that
beautifully fits the CMB as well as many other astrophysical data.
Apart from this concordance model, many signatures from various new,
expected or hoped for phenomena can possibly be detected by Planck. I
will review the constraints we have on them. Another interesting
aspect of CMB observation is that it allows to directly probe the
matter distribution in the Universe, either from the spatial distortion
of the CMB map that dark matter induces, or from the spectral
distortion, thus providing new, independent and convincing tests of the
concordance model.
Finally, I will discuss some aspects of the the BICEP2 claim of
detection of primordial gravitational waves signature on CMB
polarization and present some of the possible next steps of CMB studies. 
Bibliography
 Articles
 arXiv:1303.5072, Planck 2013 results. XII. Component separation
 arXiv:1303.5076, Planck 2013 results. XVI. Cosmological parameters
 arXiv:1303.5077, Planck 2013 results. XVII. Gravitational lensing by largescale structure
 arXiv:1303.5078, Planck 2013 results. XVIII. Gravitational lensinginfrared background correlation
 arXiv:1303.5079, Planck 2013 results. XIX. The integrated SachsWolfe effect
 arXiv:1303.5083, Planck 2013 results. XXIII. Isotropy and statistics of the CMB
