Is it Love, a “Supermoon” or Just an Illusion?
The full moon will “fill the sky like a big pizza pie” this Saturday and good for you if you conclude “that’s amore!”, but scientists say in their usual deflating way that it’s just another perigee moon, or what’s recently been dubbed a Supermoon. The full moon this Saturday will indeed be 14% bigger and 30% brighter. This is due to the moon making its closest approach to the Earth at about the same time that it appears full. This combination of events is not particularly uncommon as the attached video from NASA explains - it happens on average about once every, well, 12 moons, but combined with mostly clear skies predicted for Saturday night and we denizens could be in for a treat. Best viewing times are soon after the moon rises when it is closest to the eastern horizon (around 7pm).
But, the real reason why the moon may appear so big at times may surprise you. Like amore, it may be all in our heads.
It turns out that our brains and the way they process visual data have a lot more to do with how big the moon appears to us than the moon’s orbital eccentricities. Although it is still not completely understood (brain science is one of those final frontiers), some scientists believe the Moon Illusion is an example on a grand scale of a well known optical illusion called the Ponzo Illusion (which may be best illustrated here).
Illusion, Supermoon, or love? Either way, enjoy!