Wendy Freedman

Born on 17 July 1957, Wendy Freedman is a renowned astronomer who was instrumental in precisely measuring the Hubble constant and determining the age of the universe. Freedman received both her BSc and PhD in astronomy and astrophysics from the University of Toronto. In 1984 she accepted a position as a postdoctoral fellow at the Carnegie Observatories in Pasadena, California. In 1987 Freedman became the first woman to join Carnegie’s permanent staff, and in 2003 she became its director. She also initiated the Giant Magellan Telescope project and served as chair of its board of directors from the project’s inception in 2003 until 2015. In 2014 she joined the faculty of the University of Chicago as the John and Marion Sullivan University Professor of Astronomy and Astrophysics. Freedman first rose to prominence leading the Hubble Space Telescope Key Project, which began in the mid 1980s and involved an international group of some 30 astronomers. The team used the Hubble telescope to study Cepheid variable stars in order to estimate intergalactic distances and thus determine the expansion rate of the universe. In 2001 the team announced that it had determined the age of the universe to be 13.7 billion years and the value of the Hubble constant to be 72 km s^-1 Mpc^-1. Various studies have tweaked those numbers since then, and a puzzling discrepancy in the value of the Hubble constant continues to intrigue astrophysicists (see the article by Mario Livio and Adam Riess, Physics Today, October 2013, page 41 ). (Photo credit: University of Chicago)

Date in History: 17 July 1957