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Monday · June 20 2005

Summer Moon Illusion
This is the week to see the giant Moon, hanging low in the sky — an optical illusion.

Archived: To look at » June 2005
What you had to say:
June 25 2005

Do you know why it looks big? I just read up on this. It's not because it's any closer to the earth. Nor is there any enlarging effect caused by the earth's atmosphere. Technically, the apparent diameter of the moon is always the same no matter when you look at it, or where it is in the sky when you look.

It looks bigger only because our brains tell us that it looks bigger. Scientists don't completely understand this but somehow our brains always assume that the sky is like a room we're standing in, which means that we assume that the top of the sky (the ceiling) is closer to us than the horizon (the walls). So when the moon appears just over the horizon, our brains assume that it is farther away than usual and adjust the size of the image in our heads accordingly, making it look bigger than it really is. One way to counteract this effect is to screw up the way your brain interprets distance by bending over and looking at the moon on the horizon through your legs. If you do that, it appears normal-sized again.

June 25 2005

Whoops. Should've hit the link before I posted that, eh?

© 2005 Jason Keglovitz