Gravitational acceleration is the rate at which an object accelerates towards a massive body due to gravity. On Earth, this acceleration is approximately 9.81 m/s², meaning that an object in free fall increases its speed by about 9.81 meters per second for each second it falls. This value can vary slightly depending on altitude and location. This phenomenon is a result of Isaac Newton's law of universal gravitation, which states that every mass attracts every other mass. The strength of this attraction depends on the masses involved and the distance between them. Gravitational acceleration is crucial for understanding the motion of objects in space and on Earth.