What Is the Moon Illusion?

Have you ever noticed how the moon seems larger when it's on the horizon than it does when it's higher up the in sky? This visual phenomenon is known as the moon illusion and has been a topic of interest since ancient times. Why does this illusion occur? Learn more about some of the different theories and explanations for the moon illusion.

_{Top Image by TexasEagle, Bottom Image by Janet Crum}