Perception & Illusions: the Moon.

Shouldn't those be the same? An illusion is nothing more than a perception gone wrong. Maybe the most important part is that you will have to discover that your perception is wrong! Otherwise how would you know that what you saw (heard, et cetera) was an illusion?

Ever thought about the moon as an illusion?
No, don't get me wrong, I do not state that the moon is an illusion, no, it does exist, and we do see it, and it's there (at least, I believe it is, since personally I've never been there).
So how can the moon be an illusion?

When you look up at the sky, and there's a moon visible, you'll experience a yellow disc, far away. But if you see the moon somewhere at the horizon, you will see a larger disc. It still is far away, but it seems bigger. That could be the illusion?
In fact, it isn't. The illusions is when you see it up in the sky. At the horizon you see it in its full glory, full size, the real size. Up in the sky? Well, your brain knows that it is far away, very far away, and to experience that, and with no clues (as you have when you see it on the horizon) about its actual size, the brain makes it smaller than it really is.

So the illusion is not what you perceive. What you perceive is correct, there is a moon, and it's far, far away, unreachable for an average person. But, in order to perceive that, you brain delivers an illusion, a smaller moon.


for further explanation: http://science.nasa.gov/headlines/y2005/20jun_moonillusion.htm