Planetary Motions

Book excerpt: Students in an introductory physics class learn a variety of different, and seemingly unconnected, concepts. Gravity, the laws of motion, forces and fields, the mathematical nature of the science - all of these are ideas that play a central role in understanding physics. And one thing that connects all of these physical concepts is the impetus the great scientists of the past had to develop them - the desire to understand the motion of the planets of the solar system. This desire led to the revolutionary work of Copernicus and Galileo, Kepler and Newton. And their work forever altered how science is practiced and understood.