Thursday, January 24, 2008

Rainbows

What is there about a rainbow that evokes the visceral appreciation as we feel? I know some people will relate it to the promise in the Bible that God will never again destroy the Earth by flood. But for those who don't refer everything back to the Bible, there is still the thrill that comes from seeing that stupendous splash of color. It does seem like a gift that Nature has presented. And here is this morning's rainbow as I saw it through my back window.


Of course, we know that there is an explanation . . .

Scientific explanation

The rainbow's appearance is caused by dispersion of sunlight as it goes through raindrops. The light is first refracted as it enters the surface of the raindrop, reflectedangles, with the most intense light at an angle of 40°–42°. The angle is independent of the size of the drop, but does depend on its refractive index. Seawater has a higher refractive index than rain water, so the radius of a 'rain'bow in sea spray is smaller than a true rainbow. This is visible to the naked eye by a misalignment of these bows.[2] off the back of the drop, and again refracted as it leaves the drop. The overall effect is that the incoming light is reflected back over a wide range of

The amount by which light is refracted depends upon its wavelength, and hence its colour. Blue light (shorter wavelength) is refracted at a greater angle than red light, but because the area of the back of the droplet has a focal point inside the droplet, the spectrum crosses itself, and therefore the red light appears higher in the sky, and forms the outer colour of the rainbow. Contrary to popular belief, the light at the back of the raindrop does not undergo total internal reflection and some light does emerge from the back. However, light coming out the back of the raindrop does not create a rainbow between the observer and the sun because spectra emitted from the back of the raindrop do not have a maximum of intensity, as the other visible rainbows do, and thus the colours blend together rather than forming a rainbow.

http://en.wikipedia.org/wiki/Rainbow (with lots of photos and more information)

I've included the entire physical explanation taken from Wikipedia, because I want to see if that explanation increases my pleasure when I see a rainbow. And, the answer is, that I see there are more kinds of pleasure than one. It gives me intellectual pleasure to know . . . to understand . . . the processes that create a rainbow. This has nothing to do with the great wave of joy I feel when I look out and see that a rainbow has come to live out its short life just beyond my back yard. Yet, I am glad to have both kinds of pleasure. Here is the left end of the rainbow.


We're all familiar with the Irish belief that at the end of the rainbow there is a pot of gold. But looking at this full arch of rainbow I can't help wondering whether there is a pot of gold at both ends!

I found a website that explores the different ways people have thought about rainbows, all really interesting to read. The last two short paragraphs kind of sum it up for me:

The rainbow is a bridge between the real and imaginary. It is looked at as a magic bridge on one hand, but on the other hand, people say a project doomed to fail is one built on a rainbow. A person who chases rainbows is someone who never accomplishes anything. I wonder what people think about us, rainbow makers.

People all over the world have different beliefs and different ways of looking at and understanding the same thing. We can be sure when a rainbow appears everyone is struck by its magic and its beauty. There is no doubt of that. What is the real meaning of the rainbow? Go look at one and you will know. Without words, without pictures, with a feeling inside you. Yes, there are things we just know and those are the important things in our life. The things that do not need words.

http://www.zianet.com/rainbow/frrelig.htm


So, now I need to take a walk down to see if the creek is still flowing. Oh . . . I didn't mention that it was? LOL I didn't find out myself until after dark last night. Now, it's already 10:20 and I'm sitting here at the computer. I've taken care of my little critters, including the outside birds, and even though mine are clamoring to be let out to fly, I'm going to take some time to go see the creek. (I looked for the batteries to my video cam and, so far, haven't found them. So, no video--just still shots. Oh, well.)

Thanks for joining me here. Sorry if I'm not consistent about posting something, but I have to follow how I'm feeling and what's happening to stir my imagination.

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And they have rainbows in Tennessee, too. (smile) Here's one sent to me by my nephew Douglas, taken at his work place.



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