ABSTRACT
This chapter provides elementary notions on several topics pertaining to the general theme of orbital perturbations of bodies of the Solar System. After the statement of the general problem of perturbations, the relativistic precession of the perihelion of Mercury will be treated. From a historical perspective, Newton’s Principia paved the way to many investigations. Today, precise ephemerides of the planets and their moons are calculated with very refined methods, which take into account a large number of perturbing factors and general relativity corrections. The theory of the movement of the Moon is one of the most challenging problems of celestial mechanics. As a preliminary remark, analytical methods have shown since long that the semi-major axes, the mean motions, the eccentricities and the inclinations of the great planets do not have appreciable secular inequalities. The Solar System offers many other interesting problems of gravitational perturbations and interaction, among planets, their moons and asteroids.
