The sky isn't blue either, it just appears that way.
If something appears to be a color, it is that color, because that is what color is.
The sky may be blue because of a bunch of physics reasons, but everything is the color it is for a bunch of physics reasons. The grass is green because it reflects light in a wavelength that our eyes pick up and our brain defines as green.
And here is a source for the sky being blue:
http://spaceplace.nasa.gov/blue-sky/en/
lol do you have aspergers
I hope not. It'd hurt our reputation.
He does kind of seem like one, though, given his singleminded obsession to trolling the BLF.
Edit: I am impressed. Tony managed to argue over the blueness of the sky.
Edit 2: Huh, we got the same source. Second result on google, anyway.