Perturbations

This insight into celestial mechanics described the small additional gravitational influences, known as perturbations, that celestial bodies exert on one another, influencing their orbits. It was crucial in proving that the Solar System is stable over long periods, despite these slight mutual influences.
 Pierre-Simon Laplace France 1799 Perturbations

This insight into celestial mechanics described the small additional gravitational influences, known as perturbations, that celestial bodies exert on one another, influencing their orbits. It was crucial in proving that the Solar System is stable over long periods, despite these slight mutual influences.