1.4. CONCLUSIONS

The pre-WMAP CMB angular power spectrum assembled from multiple experiments is very well fit by a six-parameter model. Of these six parameters, the vacuum energy density _V and the redshift of reionization z_ri are still poorly determined from CMB data alone. However, the well-determined parameters either match independent determinations or the expectations from inflation:

• The baryon density _b is determined to 10% and agrees with the value from Big Bang nucleosynthesis.
• The age of the Universe is determined to 11% and agrees with determinations from white dwarf cooling (Rich 2003), main sequence turnoffs, and radioactive decay.
• The predicted shape of the LSS power spectrum P(k) agrees with the observed shape.
• The curvature _k is determined to 4% and agrees with the expected value from inflation.
• The spectral index n is determined to 4% and agrees with the expected value from inflation.

The angular power spectrum of the CMB can be computed using well-understood physics and linear perturbation theory. The current data set agrees with the predictions of inflation happening less than 1 picosecond after the Big Bang, the observations of light isotope abundances from the first three minutes after the Big Bang, and the observations of LSS in the current Universe. The inflationary scenario and the hot Big Bang model appear to be solidly based on confirmed quantitative predictions.

The greatly improved CMB data expected from WMAP, and later Planck, should dramatically improve our knowledge of the Universe.