WHY DOES THE MOON LOOK SO BIG ON THE HORIZON

Have you ever wondered why the moon appeared so much larger when it is close to the horizon compared to straight up in the sky?

This is actually an optical illusion or visual phenomenon known as Emmert's Law.

Emmert's Law states that the size of an object in our vision is related to the distance our brain perceives the object to be.

When the moon is directly above us the brain knows that the moon is at a relatively far distance and sizes the moon accordingly.  However, when the moon reaches the horizon the brain knows that the horizon is only a few miles away and adjust the image of the moon we see.

by Dr. Craig Miller | Eye Columbus