Bethe Public Lecture by Wendy Freedman
John and Marion Sullivan University Professor in Astronomy and Astrophysics
University of Chicago

Title:  How Fast is the Universe Expanding?

Host:  Abigail Crites

Abstract:  In 1929 astronomer Edwin Hubble discovered a universe filled with galaxies, and even more incredibly, a universe in which the galaxies are participating in an overall expansion of space. The current rate of expansion, called the Hubble constant, is a measure of the age and size of the universe. It has remained an exceedingly difficult quantity to measure accurately, and decades of effort have led to intense debates about its value. Recently, a new debate has emerged about the Hubble constant, potentially calling into question the standard model of cosmology. For the past 20 years, astronomers have observed the entire universe to be expanding at an increasing rate, pulled apart by a cosmic force, unexplained by any of our current physical theories. Could there be more exotic physics yet to be uncovered? I will describe the current state of cosmology and my work with the Hubble Space Telescope that has led to some of the most precise measurements of the Hubble constant made to date. I will also present some new data from the recently launched James Webb Space Telescope that promises to resolve many of the issues currently confronting these measurements.