The law of universal gravitation describes the attractive force that exists between any two masses in the universe. This force is directly proportional to the product of the two masses and inversely proportional to the square of the distance separating their centers. Mathematically, this relationship dictates that the force decreases rapidly as the distance between the interacting objects increases. This principle provides the foundational framework for understanding orbital mechanics, describing how celestial bodies, such as planets orbiting stars or moons revolving around larger planets, maintain their stable trajectories. It is a critical concept in classical mechanics, allowing for the prediction of gravitational interactions within complex systems, from terrestrial tides to the dynamics of the solar system.