Suzanne Staggs

From measurements of its remnant radiation (the cosmic microwave background or CMB), we comprehend more about the primordial universe than one might have guessed possible.  Data  from the Planck satellite have been compressed to a set of six parameters describing initial conditions for its evolution.  Meanwhile, measurements of the present-day universe reveal multiple aspects of  the state to which it has actually evolved. This before-and-after comparison is not new, but the precision of before-and-after parameter estimates is now dazzingly high, and interesting disagreements may be emerging.   Their resolution could require new physics in the cosmological model, or we might discover errors in Planck, or  in more  local measurements, or both.   Recently, data from the WMAP satellite have been combined with data from the Atacama Cosmology Telescope (ACT)  for an independent prediction.   To compete with the powerful data set provided from a  major space mission requires years of observations from bespoke arrays of  thousands of detectors cooled to 100 mK,  deployed on a special-purpose 6 m telescope on an arid plateau at 17,000 ft. The instrument and the results of the independent WMAP+ACT predictions will be described, along with a look at the power of forthcoming data sets.