TEST BANK FOR An Introduction to Modern Astrophysics By Carroll B.W. and Ostlie D.A.

1.1 From Fig. 1.7, Earth makes S=P˚ orbits about the Sun during the time required for another planet to make S=P orbits. If that other planet is a superior planet then Earth must make one extra trip around the Sun to overtake it, hence S P˚ D S P C 1: Similarly, for an inferior planet, that planet must make the extra trip, or S P D S P˚ C 1: Rearrangement gives Eq. (1.1). 1.2 For an inferior planet at greatest elongation, the positions of Earth (E), the planet (P), and the Sun ...