Kepler\'s First Law was proposed in about 1605 on the basis of celestial observations; it was later confirmed using Newton\'s Laws of Motion. According to Kepler\'s First Law, the orbits of planets (and other bodies such as asteroids) revolving around the Sun are ellipses with the Sun at one focus. Polar coordinates are ideally suited for describing planetary orbits, because the description of an ellipse in polar coordinates assumes that one focus of the ellipse is at the origin. Recall a few facts about ellipses in polar coordinates. One equation of a conic section in polar coordinates is where 0 lessthanorequalto theta lessthanorequalto pi. When the eccentricity satisfies 0 Solution planet earth has the most nearly circular orbit.