Bailyn, Charles. ASTR 160: Frontiers and Controversies in Astrophysics, Spring 2007. Yale OpenCourseWare: Astronomy, Accessed 19/9/14 http://oyc.yale.edu/astronomy/astr-160/lecture-1 License: Creative Commons Attribution-Noncommercial-Share Alike 3.0 license Professor Bailyn introduces the course and discusses the course material and requirements. The three major topics that the course will cover are (1) exoplanets--planets around stars other than the Sun, (2) black holes--stars whose gravitational pull is so strong that even their own light rays cannot escape, and (3) cosmology--the study of the Universe as a whole. Class proper begins with a discussion on planetary orbits. A brief history of astronomy is also given and its major contributors over the centuries are introduced: Ptolemy, Galileo, Copernicus, Kepler, and Newton.