Astronomy 162 - Stars, Galaxies, & The Universe

How do we measure distances on cosmic scales? This lecture describes the rungs in the cosmic distance ladder from measuring the AU in our own Solar System out into the Hubble expansion of the universe. These distances form the basis of the measurements that let us piece together the present, past, and future history of the expanding Universe, setting the stage for next week's lectures. Recorded 2006 February 24 in 1008 Evans Laboratory on the Columbus campus of The Ohio State University.