Why does the moon look so large on the horizon?

The phenomenon of the moon appearing larger near the horizon, known as the moon illusion, has puzzled scientists for centuries. Various theories have been proposed, including atmospheric refraction and perceptual factors. While atmospheric effects can slightly alter the moon's appearance, the brain's interpretation of distance and size plays a significant role. Theories such as the apparent distance theory and the size-contrast theory suggest that our perception is influenced by surrounding objects. Despite extensive research, the exact cause of the moon illusion remains unresolved, as acknowledged by NASA.