Physical Society Colloquium

Even More from the Cosmic Microwave Background:
Its Polarization and Finest Features

Suzanne Staggs

Princeton University

Overwhelming evidence indicates that our complicated present-day universe (full of galaxies and stars and planets and at least some lifeforms) is evolving from a simple beginning as a dense cloud of hot plasma. The leftover, cooled-off radiation from the primordial plasma still permeates the universe, and is called the Cosmic Microwave Background (CMB). Inflation, reionization, and dark-matter- driven oscillations of the primordial plasma polarize the CMB slightly. The radiation's interactions with gas and dark matter en route to the current epoch imprint its distribution with fine-scale features . The DASI experiment detected small polarization anisotropies in the CMB in 2002, and several new polarization results have come out since. I will elaborate on polarization measurements from the high-resolution CAPMAP, a 16-element correlation polarimeter array operating at 90 GHz, the sweet spot in the foreground spectrum. Several experiments are gearing up to measure the CMB anisotropy at fine angular scales, below those to be probed by the PLANCK satellite. I will conclude by providing some details of the ACT project, which is now being construced and is designed to make fine-scale maps of the CMB.