The CMB and Cosmological Parameters

Finally, we can understand the behavior of the CMB power spectrum just defined using the physical processes and mathematics of the previous sec- 

There are yet other physical effects that affect the pattern of CMB fluctuations. Although the photons and baryons are tightly bound to one another via scattering, the coupling is not perfect. Hence, there is a scale (known as the Silk damping scale) below which the photons can stream freely and wash out perturbations. This free-streaming damps perturbations on small scales. 

There are, however, some puzzles and anomalies. The polarization data indicates that the Universe reionized at redshift zr 20+g° rather than the expected zr 6 there are also some outliers from the smooth best-fit power spectra at low and moderate l which may just be statistical flukes but are suf- 

We expect that all of these mysteries will be cleared up — and new ones generated — by the release of further data from WMAP expected in 2004 and beyond, many ongoing ground- and balloon-based observing campaigns, and eventually the Planck Surveyor satellite, due to be launched in 2007. 

I would bke to thank the organizers of the Cargese school, and in particular Alain Blanchard, for a wonderful time. I would also like to thank my many CMB collaborators in the MAXIMA, BOOMERANG, COMBAT and Planck 

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