Why do you see seven colours in a rainbow?

Those are the only ones that people talk about, because that's the longest list of

colors that a lot of people can remember. But the truth is that there are billions of

colors in the rainbow. A lot of them don't even have names because there are so

many. In fact, the best way to describe it is: ALL the colors are in the rainbow. If

it's something your eye can detect, then it's there.