Prof. Suzanne Staggs, Princeton University

"Looking at the past with the Atacama Cosmology Telescope to predict the state of the universe today"

Abstract: From measurements of its remnant radiation, we comprehend more about the primordial universe than one might have guessed possible. Knowledge of the present-day universe gives hindsight for modeling the early universe and its dynamics. Data from the Planck satellite have been compressed to a set of six parameters describing initial conditions. Those six can be used to predict aspects of the present-day universe, including its present expansion rate. Measurements of the expansion rate obtained from the recessional speeds of supernovae in the local universe disagree with the predictions from Planck. The fault could be due to Planck, the model, or the local measurements. 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.