April 04, 2008

*Ask Jen: Mooning Edition

Jim (yay!) asks: "So Jen, why does the moon sometimes look tiny like a dime and other times it is huge like a baby's head?"

Well, Jim, I am glad you asked. The moon has an elliptical orbit, so sometimes it is closer to the earth...but that does not account for the dramatic "change" in size during one night. What I think you are referring to is the illusion that the moon is huge near the horizon, and smaller as it rises in the sky.

This change in size is only seen by the human eye--cameras do not record the same phenomena. If you take a series of pictures of the moon throughout the evening, you'll see that the moon remains the same size. Our brains must be tricking us!

The prevailing theory on this is that we judge the size of the moon compared to what's nearby. So when the moon is near a house in our sight-line, for example, we think the moon is larger than when we see the moon hanging out by itself.

Personally, I have seen a ginormous orange moon on the horizon a couple times that I don't believe can be explained away by the above theory. It happens when the moon rises above the waste treatment plant east of my parents' town...so I think in my non-scientist way that the gases and chemical whatnot affect the appearance of the moon at those times. Seriously, it's HUGE! Then it rises and becomes white and normal-sized.

Is my mind just being tricksy? Until I start carrying a camera everywhere I go--or holding up dimes against the moon--I won't know for sure.

Do you have a question for me? You can e-mail it. If I know the answer, I'll answer it. If I don't know the answer, I might make something up.

Posted by Jennifer at April 4, 2008 12:35 PM | TrackBack


Cool. Of course you know that I'm going to have to carry a camera everywhere I go now. I profane of pocket change so the dime option is out for me.

Posted by: Jim at April 6, 2008 08:50 AM