The European Space Agency’s Planck satellite, launched in 2009, surveys the entire sky at microwave and submillimeter wavelengths with much better sensitivity, angular resolution, and spectral coverage than was available to earlier generations of microwave orbiters. Planck’s main objective is to measure the parts-per-million spatial temperature fluctuation of the cosmic microwave background. The CMB is the light from the first moments of cosmic transparency, 3.7 × 105 years after the Big Bang. Precision measurements of its tiny, random departures from thermal isotropy on all angular scales inform and constrain cosmological models. Now the Planck collaboration has presented the results of its first 16 months of observation in 28 simultaneously released papers; the team’s overview paper is cited below. The principal finding is that cosmology’s widely accepted concordance model is alive and healthier than ever. Some of its fundamental parameters have suffered interesting tweaks, but none that clearly require new physics or additional parameters in the model’s scenario of cosmic birth, inflation, and structure formation. For example, the cosmic inventory of matter and dark energy has shifted by a few percent toward more matter, with a consequent slight reduction of the expansion rate and a mere hundred million years added to the previous best estimate (13.7 × 109 years) of the age of the universe. (P. A. R. Ade et al., Planck collaboration, Astron. Astrophys., in press, http://arxiv.org/abs/1303.5062.)—Bertram Schwarzschild
