Here's why it happens:
* Atmospheric Perspective: When the moon is near the horizon, it appears through a greater thickness of atmosphere. This atmosphere can refract (bend) light, making the moon seem slightly larger and distorted. However, the actual size change is very minor.
* Depth Perception: Our brains perceive objects in the distance differently than objects close up. When the moon is on the horizon, we compare it to familiar objects like trees and buildings, which gives us the sense that it's much larger than when it's high in the sky, where there's no comparison.
* Ponzo Illusion: This is a well-known optical illusion that makes us perceive objects as larger when they are surrounded by converging lines. The horizon lines appear to converge in the distance, giving the illusion of a larger moon.
The real reason the moon appears bigger on the horizon is because of how our brains interpret the visual information, not because the moon actually changes in size.
You can test this illusion by holding a small object at arm's length and comparing its size when you look at it directly, and when you look at it through a narrow tube or a piece of paper with a small hole in it. The object will appear larger when viewed through the tube, similar to the way the moon appears larger on the horizon.
