Freedman focuses her research on measuring both the current and past expansion rates of the universe, and on characterizing the nature of dark energy, a mysterious force that causes the universe to accelerate its expansion. A decade ago she led a team of 30 astronomers who carried out the Hubble Key Project to measure the current expansion rate of the universe. The project’s final results determined the age of the universe as approximately 13.7 billion years, resolving a longstanding debate regarding previously wide-ranging estimates. Freedman served as chair of the board of directors of the Giant Magellan Telescope Project from its inception in 2003 to 2015. She is an elected member of the National Academy of Sciences and of the American Philosophical Society. Freedman also is an elected fellow of the American Academy of Arts and Sciences and of the American Physical Society. Her honors also include the Gruber Cosmology Prize.