Moon

Originally posted by tomtom232
Yes, but maybe it has a significant effect on our brains for us to see the sun/moon as bigger when near or below the horizon?

How would the fact that it appears somewhere it isn't have any effect on perception of size?

The perception of size is a purely psychological illusion and has nothing to do with optics.

Originally posted by googlefudge
How would the fact that it appears somewhere it isn't have any effect on perception of size?

The perception of size is a purely psychological illusion and has nothing to do with optics.

I know that.

How would the fact that it appears somewhere it isn't not have any cause in a psychological illusion?

Edit: It must have something to do with distortion, diffraction, the way our eyes work, and the way our brain interprets what our eyes "see." If it was purely psychological then some would see it as bigger and some wouldn't.

Originally posted by tomtom232
I know that.

How would the fact that it appears somewhere it isn't not have any cause in a psychological illusion?

Edit: It must have something to do with distortion, diffraction, the way our eyes work, and the way our brain interprets what our eyes "see." If it was purely psychological then some would see it as bigger and some wouldn't.

Nope, because you can create the same (or similar) illusions with no optics involved at all.

We all get this illusion because our brains work in similar ways.

Look at the wiki link on it earlier in the thread, there is an illusion on it [linked below]
that is (as far as I know universally seen) but has nothing to do with optics at all
and is simply a function of how our brains work.

http://en.wikipedia.org/wiki/Ebbinghaus_illusion

Originally posted by googlefudge
Nope, because you can create the same (or similar) illusions with no optics involved at all.

We all get this illusion because our brains work in similar ways.

Look at the wiki link on it earlier in the thread, there is an illusion on it [linked below]
that is (as far as I know universally seen) but has nothing to do with optics at all
and is simply a function of how our brains work.

http://en.wikipedia.org/wiki/Ebbinghaus_illusion

Well, there you go. I looked at all three of the illusions given in that wiki and the circles appeared the same size as well as the lines in the Ponzo Illusion.

Actually, I was able to trick myself into seeing either circle as bigger or smaller but with the Ponzo illusion the lines just look the same size.

But maybe there is a more radical example that will trick my primary visual cortex? If not then I would have to assume that this has nothing to do with the sun/moon because I see them as bigger when they are close to the horizon.

From the wiki:

Other recent research suggests that an individual's receptivity to this illusion, as well as the Ponzo illusion, may be inversely correlated with the size of that individual's primary visual cortex.