To answer the title question -- not much. I know, this is a "weather blog" but this was just too mind-blowing to ignore...
I was trawling around for blog topic ideas on one of my favorite sites, the Astronomy Picture of the Day and came across this that was posted earlier this month.
The question is: Are the squares marked "A" and "B" the same color?
Surely, they are not. But actually, they are. Those of you who are Photoshop saavy can copy the image off this web site and see for yourself.
And if you want to see the explanation behind it, here is the original site by the MIT professor who created it.
OK, neat mind trick, but I wanted to post it here because there is a similar effect that can mess with your head and the moon.
Ever notice when the moon is near the horizon, sometimes it looks like it's three times as big? I always thought it was some sort of atmospheric effect where the air bends the lightwaves to make it appear larger. But the fascinating part is, if you take a picture with your camera, the moon comes out looking normal.
In this photo of a moon rising over Seattle, the camera shows what your mind doesn't see -- the moon stays the same size, although I'm sure to the photograher, the moon probably looked huge when it was near the horizon and skyline.
Here are some links to explanations of the moon trick:
Original thinking: http://unmuseum.mus.pa.us/exmoon.htm
Newer explanation that's surfaced over the past few years: http://facstaff.uww.edu/mccreadd/