It can be amusing and perhaps, at times, frustrating how our mind plays tricks on us and causes us to perceive something that isn't exactly reality. An illusion that I find quite fascinating is the moon illusion. The moon illusion is the illusion that the moon appears larger when it's near the horizon than high in the sky. As I'm sure has happened to anyone reading this, there have been many instances where I look just above the horizon at night and stare in awe at an orange moon that appears to be incredibly large compared to others nights when it was higher in the sky. Every time I experience one of these moments I am always amazed at how big the moon can look, but I have never wondered why the moon may appear this way some nights.
So, why do we perceive the moon to be larger at the horizon? There are a few possible explanations, but one explanation for the illusion is that we humans are not able to judge the very long distance of the moon. The moon is about 240,000 miles away from Earth, so when we see the moon high in the sky, there is not much to compare it to. On the other hand, when the moon is near the horizon we perceive it as larger because of what we compare it to along the horizon, such as trees or buildings. Even though I am aware that this is an illusion, it still fascinates me that the moon appears this way at the horizon.