|How far is the rainbow?~ Images by Jonathon Stone. ©Jonathon Stone.
"My sister and I were driving alongside a thunderstorm a few miles south of Knoxville, Tennessee. The storm had just passed the interstate and we could see a faint portion of a rainbow off in the distance. Then something cool happened; a rainbow began to form in the mist of the vehicles in front of us. It soon turned into a full spectrum appearing and disappearing in the mist.
What was really interesting though, when the trees cleared we could see that the two rainbows were connected around the same point and actually one rainbow! Though one seemed just ahead of us and one miles away!"
It is impossible to say how far away is a rainbow because it has no distance, no size or indeed real existence. It is purely a collection of rays from glinting water drops that happen to be intercepted by your eye.
It is valid, however, to ask how far away are the water drops forming it. But even then there are difficulties.