|So it is green because it reflects green and we see green. |
Actually BHX got this one right. It's not green. It just reflects wave with such length, that our brain interprets it as green colour.
See this as we were computer, and the wavelength was input, given by "World" through input device("Eyes"). Now this input is garbage when you don't know how it should be stored, used, etc. Moreover, it may be interpreted in many ways, just the same as computers handle language codings differently(the case I'm sometimes getting some strange letters, like óəπźŋ instead of the ones I wrote).
You may also look at it as at at some cipher - like http://en.wikipedia.org/wiki/Caesar_cipher
. Ciphered text makes no sense to you - but it's the same text that you'll read when you decode it, just wrote differently. If someone has been taught reading and speaking in english ciphered by Caesar cipher, he would understand this "garbage" perfectly fine.
And that's what our brain does. You see green, because brain is hard-coded to see green. There isn't anything surprising in telling you, that you could react differently - so instead of seeing green, you would feel warmth. It would be perfectly fine, because your brain just computed an input.
This post is already getting long on some offtopic thing, but I felt like I had to cover it - I find it interesting. To finish my thought, take a look at this funny substance: http://en.wikipedia.org/wiki/Miraculin
. You can extract it from funny fruit, and it will change the way your brain reads "taste" input. That's strange, isn't it? ;)
I don't believe UFO came to our planet. At least not in the way we could notice them.
I assume, that if some race is capable of coming to Earth undetected, and keeping away from our sight in space, they are so advanced, that there's no way we could detect - or see - them if they didn't want us to see them. And I believe they don't.
I believe seeing UFO is the same case as seeing God - brain isn't perfect. It tends to interpret things, not save them as they are. If you don't understand something, you may want to explain it somehow, hence God or aliens. I've seen some scientist claiming, that he's found "God's dimension", proofs for existence of God, and proofs of UFO existence(and used UFO's technology to create his own blueprint of spacecraft). He said that we could have been way ahead, but instead of listening to him, people are laughing at him. I don't know if he's right, but he looks a bit like a loony to me.