Gravitational acceleration is the acceleration experienced by an object due to the gravitational pull of a massive body. It is a fundamental concept in classical mechanics, representing the rate of change of velocity caused by gravity. The magnitude of this acceleration depends on the masses of the interacting bodies and the distance between them. On the surface of a planet, this value is often denoted as $g$. Due to the varying density and internal structure of large celestial bodies, the measured value of gravitational acceleration can differ significantly from the standardized value, and it can also vary with altitude from the planet's surface.