Friday June 9 at 7:30 p.m.

Live at Willcox Hall and via Zoom (link on WAA home page)

Searching for New Physics in the Universe’s Oldest Light

J. Colin Hill, Ph.D.
Columbia University Department of Physics

Dr. Hill will begin with a general review of the state of physical cosmology — what do we know about our universe, and how do we know it? He will then discuss recent and ongoing work focused on attempts to resolve a potential discrepancy amongst some measurements of the current cosmic expansion rate (the “Hubble  tension”). He will then describe how this discrepancy could potentially be resolved via the introduction of new physics into our cosmological model around the time of “recombination”, the moment when photons in the cosmic microwave background (CMB) last scattered in the primordial plasma, a few hundred thousand years after the Big Bang.

He will discuss constraints on these new-physics models derived using the latest CMB data from the Atacama Cosmology Telescope (ACT), as well as new data from Supernova Refsdal just published in May, and will conclude with a look ahead to forthcoming CMB measurements from ACT and the Simons Observatory, which will definitively detect or exclude these scenarios.

Free & open to the public!