Dr. Wendy Freedman is University Professor at the University of Chicago. Until recently, she served as the Crawford H. Greenewalt Director of the Carnegie Observatories in Pasadena, California. She also chairs the Board of Directors for the Giant Magellan Telescope (GMT), a 25-m optical telescope scheduled for construction in Chile in 2020. Her principle research interests are in observational cosmology; Dr. Freedman was a lead investigator for a team of astronomers who carried out the Hubble Key Project to measure the current expansion rate of the Universe. Her current research interests are directed at measuring both the current and past expansion rate of the universe, and in characterizing the nature of dark energy, which is causing the universe to speed up its expansion.