Why The Moon Looks Bigger On Some Nights Than It Does On Others

The moon looks HUGE some nights, right? Well, yes, sort of, to you — but only because your tiny human brain contextualises it as larger sometimes than others. It's never actually any closer. It's just a confluence of a few different optical illusions screwing with your head.

So here's what happens. First, the moon seems larger, usually, when it's near the horizon. One reason for the is that there are more reference points, like trees and buildings, to compare to the moon. When it's just sitting alone, high in the night sky, the moon just looks "regular" sized.

It's the Ebbinghaus effect — you look taller standing next to a child than you would standing next to Shaq. The other thing is that our brains are used to things on the horizon shrinking, since that typically means they're farther away.

So when the moon doesn't shrink as it crosses the horizon, years of understanding perspective kicks in and tells us the moon got humongous. So there you go. Your brain is dumb, and the moon is just the moon. [YouTube]


Comments

    that boggled my tiny human brain.

      but when the moon is on the horizon perspective should still matter as we're looking at however many kilometres of land plus the stratosphere instead of just straight up, and why doesn't this theory affect the sunset? so many questions, and the only obvious answer is the moon has turned into a zombie and is coming for us

    "It’s never actually any closer"... yes it is. The moon has an eliptical orbit and can sometimes be up to 50,000km closer than at other times (and physically appear 14% larger). Doesn't affect the moon illusion though. (ref: http://en.wikipedia.org/wiki/Supermoon)

      *uses Wikipedia as a reliable reference*........ lol, but srsly, I don't disagree.

    i like the moon at horizon level test. It requires mooning the moon.

    I always thought it was something to do with refraction through the Earth's atmosphere; same with the moon. But the Ebbinghaus illusion explanation is very convincing.

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