The cosmic background radiation circa v2K

We describe the implications of cosmic microwave background (CMB) observati ons and galaxy and cluster surveys of large scale structure (LSS) for theor ies of cosmic structure formation, especially emphasizing the recent Boomer ang and Maxima CMB balloon experiments. The inflation-based cosmic structur e formation paradigm we have been operating with for two decades has never been in better shape. Here we primarily focus on a simplified inflation par ameter set, {omega (b), omega (cdm), Omega (tot), Omega (Lambda), n(s), tau (C), sigma (8)} Combining all of the current CMB+LSS data points to the re markable conclusion that the local Hubble patch we can access has little me an curvature (Omega (tot) = 1.08 +/- 0.06) and the initial fluctuations wer e nearly scale invariant (n(s) = 1.03 +/- 0.08), both predictions of (non-b aroque) inflation theory. The baryon density is found to be slightly larger than that preferred by independent Big Bang Nucleosynthesis estimates (ome ga (b) = Omega (b)h(2) = 0.030 +/- 0.005 cf. 0.019 +/- 0.002). The CDM dens ity is in the expected range (omega (cdm) = 0.17+/-0.02). Even stranger is the CMB+LSS evidence that the density of the universe is dominated by unclu stered energy akin to the cosmological constant (Omega (Lambda) = 0.66 +/- 0.06), at the same level as that inferred from high redshift supernova obse rvations. We also sketch the CMB+LSS implications for massive neutrinos.