Physical Society Colloquium

Measuring how the Universe began: current status of the cosmic microwave background

Mark Halpern

Department of Physics and Astronomy
UBC

Acoustic processes in the plasma which pervades the early Universe govern the shape of the anisotropy of the cosmic background which has been measured by WMAP and other probes, notably ACT and the South Pole Telescope. I'll describe what we have learned, and what we have not learned from precise measurements of the temperature and polarization anisotropy of the CMB. Once the Universe became transparent, these acoustic signals stopped propagating. The density variations associated with them have remained fixed in co-moving (expanding) coordinates. I'll finish by talking about CHIME, the Canadian Hydrogen Intensity Mapping Experiment, a UBC-McGill-Toronto-DRAO collaboration to measure these same acoustic features at the much later epoch when cosmic acceleration became important.