Gravitational Forces: Gravitational forces are attractive forces between objects with mass. They cause celestial bodies to be pulled towards each other and play a crucial role in celestial mechanics.
Law of Gravitation: The law of gravitation states that every particle in the universe attracts every other particle with a force directly proportional to the product of their masses and inversely proportional to the square of the distance between them. It provides a mathematical description for gravitational forces in celestial mechanics.
Orbital Motion: Orbital motion refers to the path followed by an object (such as a planet or satellite) as it revolves around another object due to gravitational attraction. Understanding orbital motion is essential in studying celestial mechanics.