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-3 License: Creative Commons Attribution-Noncommercial-Share Alike 3.0 license Class begins with a review of the first problem set. Newton's Third Law is applied in explaining how exoplanets are found. An overview of the Solar System is given; each planet is presented individually and its special features are highlighted. Astronomy is discussed as an observational science, and the subject of how to categorize objects in the Solar System is addressed. The Pluto controversy is given special attention and both sides of the argument regarding its status are considered.