Correct Option: E

The orbit of a planet around the Sun is an ellipse, with the Sun in one of the focal points of the ellipse. [This focal point is actually the barycenter of the Sunplanet system; for simplicity this explanation assumes the Sun’s mass is infinitely larger than that planet’s.] Within a planetary system, planets, dwarf planets, asteroids (a.k.a. minor planets), comets, and space debris orbit the barycenter in elliptical orbits. A comet in a parabolic or hyperbolic orbit about a barycenter is not gravitationally bound to the star and therefore is not considered part of the star’s planetary system. Bodies which are gravitationally bound to one of the planets in a planetary system, either natural or artificial satellites, follow orbits about a barycenter near that planet. Galileo believed that the inertial path of a body around the Earth must be circular. Lacking the idea of Newtonian gravitation, he hoped this would allow him to explain the path of the planets as circular inertial orbits around the Sun. When Newton solved this problem, he showed that there are four possible paths for the planets: circular, elliptical, parabolic and hyperbolic (all are conic curves). The first two curves are closed and the other two are open curves. These results were obtained for the same energy and with the sun at rest.