The Moon Illusion The moon on the horizon appears much larger than it does when it is overhead, higher up in the sky, but this is an illusion. The moon is the same size and remains the same distance from us regardless of where it is in the sky. Objects near the horizon lead the brain to think that the horizon moon is farther away than when it is overhead, so the brain mistakenly enlarges its size in our perception because the retinal images of the horizon and overhead moons are the same size.
Paul Souders/The Image Bank/Getty Images