Our recent weather pattern has brought us waves of surface moisture and colder air aloft. That combination produces showers and possible thunderstorms and even small hail. Something else is the result of those exact conditions and many people were privileged to witness at least one. I doubt you’ll ever find the end of one not alone a pot of gold there either. I’m sure you know I am talking about rainbows.
The rainbow is special for many reasons. It is an optical phenomenon that has dazzled us from the moment we viewed our first one. The National Weather Service Glossary defines a rainbow as “A luminous arc featuring all colors of the visible light spectrum (red, orange, yellow, green, blue, indigo, and violet). It is created by refraction, total reflection, and the dispersion of light. It is visible when the sun is shining through air containing water spray or raindrops, which occurs during or immediately after a rain shower. The bow is always observed in the opposite side of the sky from the sun.”
You might remember the acronym “ROY G BIV” taught in science classes to help students remember the order of the colors from the outside of the bow moving to the inside of the arc.
The process of producing a rainbow is not as complicated as it may sound and yet it is very specific. Believe it or not the rainbow as an optical phenomenon was discussed by Rene Descartes in 1637.
According to physicsclassroon.com “A light ray from the sun enters the droplet with a slight downward trajectory. Upon refracting twice and reflecting once, the light ray is dispersed and bent downward towards an observer on earth’s surface.” “As in the case of the refraction of light through prisms with non parallel sides, the refraction of light at two boundaries of the droplet results in the dispersion of light into a spectrum of colors.” They go on to say “The double refraction results in a distinct separation of of the sunlight into its component colors.”
If the light is reflected twice inside the water droplet a secondary bow is formed. That rainbow has the colors reversed with the red on the inside of the arc and the violet on the outside. If reflected three times in the drop a tertiary or third rainbow forms.
Many years ago I attended a local American Meteorological Society meeting when I worked in Spartanburg, South Carolina. We had as our guest speaker Professor Alistair Fraser, who is now Professor Emeritus at Penn State University.
His talk included a slide how showing how rainbows have been wrongly depicted in art and particularly religious art. Often the clouds, rain, sun, and rainbow were shown together as if they could all exist at the same time in the same part of the sky. The sun and raindrops have to be in opposite parts of the sky for the rainbow to form. Also, as in the painting above, Jesus is sitting on a rainbow with his feet resting on a cloud both of which are physically impossible under those circumstances.
For those of you who are old enough to remember Peter Max you will also remember the great ad campaign for “7Up” in which he painted a rainbow with the “7Up” under the arch. He changed the colors so that the red was on the inside of the arc to make the “7Up” logo stand out.
I have always been intrigued by rainbows and have had the privilege of seeing them all over the country. I have seen single rainbows and also the secondary bow. Once I actually saw the more rare event of the tertiary bow higher up in the sky above the primary and secondary bows. It’s too bad I didn’t have a camera with me at the time to get a picture of it. Just remember each time you see a rainbow it is your personal rainbow. Because it is an optical phenomenon you see the bow where you are standing and even someone standing right next to you will see a different rainbow. I look at it as God’s gift to each of us to be able to have a rainbow that is just for each one of us.
So remember, the next time it is raining at a distance in front of you and the sun is peeking through the clouds behind you look around because your rainbow is probably waiting for you to find it.
Let me know what you would like me to talk about or explain. You can comment below or email me at: firstname.lastname@example.org.