Approaches the physics of planets, emphasizing their surfaces, satellites, and rings. Topics include formation and evolution of planetary surfaces, history of the terrestrial planets, and dynamics of planetary rings. Both ASTR 3720 and ASTRr 3750 may be taken for credit in any order. Prereqs., PHYS 1110 and 1120, and calculus (MATH 1300 and 2300, or APPM 1350 and 1360). Elective for APS major and minor.