The force that puts an object into free fall is gravity. Gravity is the natural force that attracts objects with mass towards each other. Every object in the universe has gravity, but the force is only noticeable for objects with a significant amount of mass. The Earth has a large amount of mass, so its gravity pulls objects towards it. When an object is released from a height, the only force acting on it is gravity, which causes it to accelerate towards the Earth's surface. This acceleration is known as free fall.