Reflecting on Refraction
I was on a flight one morning several years ago heading north and sitting at a window in first class on the right side. I look out the window and saw something very similar to this picture. However, unlike in this picture, the plane was positioned more to the left with the first class section directly in the center of the rainbow. Hmmmmmmmm! Two thoughts: 1. Why a circular rainbow?, and 2. Why was my seat in the center?
The answer to the first question was immediately obvious. The rainbow arches that we enjoy when standing on the ground, are only that which are not blocked by the horizon. Daaaahhh! A couple more sips of coffee, and the answer to the second question hit me, and a pleasant thought that I had not considered before. Any rainbow that you see is your PERSONAL one. It is your eyes picking up a particular angle of the refraction.. Someone standing near you may see a rainbow, BUT, that is not the exact same rainbow due to the angle of view, no matter how slight. To this point, I headed to the back of the plane and saw what is presented in this picture. This picture was taken by someone in steerage behind first class. Also, keep in mind that when a rainbow occurs, the sun will always be at your back and caused by the refraction and dispersion of the sun's light by rain or other water droplets in the atmosphere:
Several years later I was skiing down a slope at Deer Valley, and went to the side of the slope to rest for a moment. It had been an intensive day on the slopes. Preparing to resume, I turned to look up the slope to be sure there was no one that would conflict with my starting down. Imagine my amazement to seeing this site looking West. In my 45 years of skiing at that point, or any other time, I had never seen this effect in the sky. It was absolutely extraordinary, not only as to glorious beauty, but that the sun was beyond the view, and not behind me. You notice the brightness of the arches as well as an additional bright concentration point on the left side. I had enough engineering courses in college to understand rainbows, but this view left me in the “dark” mentally. BTW, this picture is @ by me.
When I finished for the day, I stopped by the ski shop to ask about this phenomena. “Oh yeah!” the repair guy said. “That was a “sun dog” aka sundawg. Turning to the internet that evening I found the following offered by Wikipedia:
- Sun Dogs ARE NOT rainbows even though refraction is at play for each.
- The sun dog is a member of the family of halos caused by the refraction of sunlight by ice crystals in the atmosphere. Sun dogs typically appear as a pair of subtly colored patches of light, around 22° to the left and right of the Sun, and at the same altitude above the horizon as the Sun. They can be seen anywhere in the world during any season, but are not always obvious or bright. Sun dogs are best seen and most conspicuous when the Sun is near the horizon.
I wish sun dogs in your future.