Frontiers/Controversies in Astrophysics (ASTR 160) Professor Bailyn offers a review of what is known so far about the expansion of the universe from observing galaxies, supernovae, and other celestial phenomena. The rate of the expansion of the universe is discussed along with the Big Rip theory and the balance of dark energy and dark matter in the universe over time. The point at which the universe shifts from accelerating to decelerating is examined. Worries related to the brightness of high redshift supernovae and the effects of gravitational lensing are explained. The lecture also describes current project designs for detecting supernovae at high or intermediate redshift, such as the Joint Dark Energy Mission (JDEM) and Large Synoptic Survey Telescope (LSST). 00:00 - Chapter 1. From Acceleration to Deceleration of Universe Expansion 10:20 - Chapter 2. The Balance between Dark Energy and Dark Matter 18:59 - Chapter 3. Complications from Supernovae Brightness and Gravitational Lensing Effects 37:33 - Chapter 4. The Joint Dark Energy Mission (JDEM) and Large Synoptic Survey Telescope (LSST) Complete course materials are available at the Open Yale Courses website: http://open.yale.edu/courses This course was recorded in Spring 2007.