3:30–4:30 pm Maria Goeppert-Mayer Lecture Hall
Wendy Freedman (University of Chicago) "The Hubble Tension: Is There a Crisis in Cosmology?"
The question of whether there is new physics beyond our current standard model, Lambda Cold Dark Matter (LCDM), is a crucial unresolved issue in cosmology today. Recent measurements of the Hubble constant (Ho) using Cepheid variables and Type Ia supernovae appear to differ significantly (5-sigma) from values inferred from the cosmic microwave background (CMB) fluctuations. This discrepancy, if real, could indicate new physics beyond the standard model. In this talk, I will present recent results using data from the Hubble Space Telescope independent of the Cepheid distance scale. The Tip of the Red Giant Branch (TRGB) is a marker of the core helium flash in low-mass stars and provides a highly precise and accurate standard candle. Finally, I will describe and present preliminary results from a new program using the James Webb Space Telescope (JWST). The superb resolution and sensitivity of JWST offer a huge improvement over Hubble, which will significantly improve the measurement of galaxy distances and H0.