Lately, at night, we have noticed that the moon looks awfully close and we were wondering why this is happening. Does it have to do with the eclipse that was four days ago or is this because of some strange thing that is happening? Should we be interested or frightened?


You should be interested but certainly not frightened! This is caused by a very persistent optical illusion that all of humanity over the centuries have been curious about: The Moon illusion. Please see http://en.wikipedia.org/wiki/Moon_illusion for more information. The moon looks bigger when it's on the horizon due to an optical illusion caused by foreground objects and our perception of the dome of the sky. This is explained better on the Wikipedia website because they use pictures.

You can prove the moon is not bigger by holding your thumb and index finger a pencil-width apart at arm's length–the moon should fit inside–and comparing that to its size later in the night when it looks smaller.

As for the recent eclipse, the moon orbits at an angle to the earth on an oval shape, but the difference in distance between the earth and moon is so small that it would not be a noticeable difference to us. So the effect you are noticing is probably due to moon illusion, not the eclipse.

I hope you enjoyed the recent eclipse! They are beautiful events.

Sincerely, Katie Morzinski

 
why_does_the_moon_look_bigger.txt · Last modified: 2009/01/21 15:51 by czars · [Old revisions]