The Beaver, or Full Frost Moon is the name of this season’s luna llena. With the moonlight sparkling on a heavy frost and a beaver moving into a new bend of one of the ditches that runs by my house, I think it is well named. Our question this week was, why is the Moon bigger when it rises?
It turns out that how we perceive the moon is both highly personal and also not that well understood by modern science. This phenomenon where the moon looks bigger when it’s rising is called the “moon illusion”. In actuality the Moon is no bigger when it rises than when it is directly above.You can see this for yourself through a simple experiment; roll up a piece of paper and point it at the rising moon. Adjust the paper until the hole is exactly the same size as the moon and then tape it there. When the Moon is overhead several hours later take a look through your paper scope and you will see that it is the exact same size. No matter how we prove it though, we all still see the moon as larger when it rises! Several theories have been proposed as to the nature of this optical illusion but, there is no consensus among modern scientists as to exactly why.
A different way of relating to the mystery of the Moon comes from the Dine (Navajo) tribe. They view the Moon and the Stars in the Night Sky as relatives, beings of sorts that help us understand our relationship to space and time. Next time you watch the moon rise try opening up your imagination to see the speed of the Earth turning in the speed of her rise, or try and imagine the space between us on the Earth and the Moon as three dimensional objects in a big universe!
Special thanks to KVNF's intern Carmen Rodriguez for helping with some of the sound effects in this episode and gratitude to Aaron Watson for contributing his stunning image of the Beaver Moon on Nov. 30, 2020.
CITATIONS & STUDIES
The Moon Illusion, Wikipedia
Why the Moon Looks Bigger Near the Horizon, National Geographic
Chromatic Aberration, Wikipedia
Longitudinal and Lateral Chromatic Aberration, Image Engineering
Lyla June Johnston, Facebook
