The Moon Illusion: An Unsolved Mystery

Andrew Vanden Heuvel takes a look at the question of why the moon seems so much larger when it’s near the horizon than when it’s seen overhead. Scientists and other great thinkers from Aristotle, Ptolemy, da Vinci and Descartes have pondered this question since ancient times. The size of the moon seen from Earth doesn’t change, so it must be some sort of optical illusion.

In this short video, Vanden Heuvel presents some of the various theories and current thinking. But the debate rages on.