To See as a Scientist: The Discovery of Crepuscular Rays

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Beauty,Spring 2005
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To See as a Scientist: The Discovery of Crepuscular Rays

Amy Martin

"Wonder is a horizon-effect of the known, the unknown, and the unknowable" writes Philip Fisher in his book "Wonder, the Rainbow, and the Aesthetics of Rare Experiences". As a self-described humanist embodying a scientist's search for beauty, I must acknowledge what Fisher defines as the sliding scale of wonder. What is wondrous and thus beautiful in a scientific way to me as a quasi scientist is quite possibly insipidly dull for the scientist at large. Yet, it contains elements of the beauty of science, of the equation- the putting together of two elements to create a transformation into a new experience. Such reveling in the aesthetic beauty of my experience leads me to find the deeper scientific beauty- the beauty of the explanation. And so I have become a scientist seeking beauty, in that the explanation of my experience only enhanced the wonder of viewing it.

Wonder is the extraordinary emerging out of the ordinary. Sitting on a wall on top of Masada, I shivered in the dark night searching the sky for any sign of sun. Slowly, the sun began to rise, and though it was a beautiful sunrise full of lush Mediterranean orange, it is not the sunrise that captured my attention that morning, that continues to captivate me. After the sunrise, divine rays streamed down – that morning they evoked a spiritual wonder, they were a curtain of light and energy that seemed to be stretching out and beckoning towards me. After that breathtaking experience of beauty, I became hyperaware of this phenomenon.

And so I have seen this glory of sun and clouds time and time again since that day. Driving through New Mexico the mesas, ubiquitous red rock, encompassing achingly blue sky all were mere players that set the stage for the divine rays of the sun to kiss the earth. Again driving this time in the New England mountains, the sun's shooting rays again stopped me- urging me to notice the world around me, paused and framed that moment in my life.

Despite all this aesthetic beauty, a scientist stops and asks – Why and How? These isolated experiences, and experience of the sun that I'm sure almost all humans have seen, pushed me on to the next step of wonder- the step that all good scientists must take, the search for explanation. Why did I only get to see such flagrant beauty sometimes, when I least expected it? Why on most days do I see the sun as only a backlight that shines through the clouds, or as that comforting round ball sitting alone in a blue sky? Most often, the sky remains a flattened blue; a backdrop to life as I know it- why was the drama of the sun most often absent.

The streaming rays of sun, personified fingers aching to touch the earth, are known as crepuscular rays. The rays come from the essentially parallel columns of the sun's light. These sun rays are parallel to darkened cloud areas in the absence of sunlight. To be formed the rays need a shadow, in the instants in which they appeared so divine to me, the shadow was probably formed by a cloud. With a shadow, the sunlight breaks between the shadowed, darkened areas and the lightened areas outside of the shadow. This divides the sky into areas of shaded or sunlight air columns. Like chiaroscuro effects in art, the brightness of the sunlight column appears to our naked eye because of its contrast next to the shaded, dark air column. As in art, the difference in light and dark creates an illusion of shape that makes the light appear three dimensional instead of our normal flattened view of the sky.

Yet, we would not be able to see the rays of sunlight without aid. The light needs to be scattered, or reflected off of particles in the air. These particles can be dust or water. Whatever the particle, their basic effect is my "finger" notion- the particles make the beams appear to be originating at the sun, and then separating and spreading out over the horizon. Besides scattering, the other reason we see crepuscular rays, in reality parallel, as slanted, is because of perspective. The shadowed areas reach the ground between the sun and our eye. The shadow closest to the ground appears wider. Essentially "we know all rays are virtually parallel and they extend from the sun to your eyes, they must be descending in altitude the closer they become to you". Perspective and scattering make them appear as though they ascend and create the sentiment of divineness that so many feel experiencing crepuscular rays.

This is a simplistic example of the simplifying process. Three experiences that are "normal" to us on such a basic level – the sun, the clouds, and the existence of dust and water particles- become aesthetically extraordinary, if not scientifically extraordinary, when they are combined together. Although the sight of crepuscular rays is far more common than the sight of a rainbow, the aesthetic pleasure that is captured by viewing crepuscular rays can be and often is one of beauty and wonder. This wonder is completely relative. Since surely I am not the first or last person to see the beauty of crepuscular rays, I do not have the wonder of discovering a universal scientific "truth" from viewing the appearance of the rays multiple times. Nor was I the scientist who discovered what makes such rays appear to be radiating out over a wide area of space. Like the chemist in the lab who mixes two clear elements and emerges with Prussian blue, and not only sees the blue but knows why and how blue forms from clear, I can own the knowledge of the crepuscular ray. Not only have I seen beauty on a fundamental human, visual level, by questioning the experience of this beauty and looking beyond the experience to the explanation I see as a chemist or a physicist sees beauty. In the form of what has occurred, the aesthetic beauty is deepened. Now the sun rays are not merely sun rays, perhaps divinely inspired, I have moved from the realm of mere speculation to knowledge. Fisher writes: "At the heart of this short instance of learning is a moment of wonder composed of intellectual surprise, the unexpected and the pleasurable." In the mixture of sun and cloud and angle in which we see crepuscular rays, it is the design of nature that is so beautifully simplistic.

Or is it? Do we see crepuscular rays because of nature's design of the sunlight? Is it really the rays in contrast to the shadowed areas void of sunlight that create this visual affect? Roald Hoffman tells us that as humans we must find this beauty. "Beauty is created out of the labor of human hands and minds. It is to be found, precarious, at some tense edge where symmetry and asymmetry, simplicity and complexity, order and chaos, contend." Crepuscular rays are only as beautiful as they are to us because of our inability to see what they truly are, virtually parallel rays of sunlight and shadowed columns. In our human misgivings, our sense of perspective and our eyes interpretation of the sun reflecting off the particles in air, we create the notion of this divine image. The "story" I found on the internet explains this interaction between human fallibility and nature's design.

Still, as a newfangled scientist, I couldn't help but wonder if such a story was empirically right. The creation of why and how to simplify things as stunningly complex as the sun, the energy of light, the interaction of vision and light – this like all science to Hoffman, was just a narrative of the real world- a condensation to create simplicity where perhaps everything is complicated. As Peter Beckmann told us, the story only sticks
until the next person comes along with explanation, with the new findings, with data that is more reliable and consistent. As a scientist, this idea is where the beauty is at. All these disparate stories – from the Roman idea of the sun being pulled by a chariot across the sky to our modern notion of the sun and gravitational pull – they link back to Hoffman and Fisher. The continuation of the narrative, the possibility to expand our wonder, to build wonder upon things that once seemed ordinary and normal - the space for discovery is where the beauty in science lies.

References

1Philip Fisher, Wonder, the Rainbow, and the Aesthetics of Rare Experiences. (Cambridge, Mass: Harvard University Press, 1998) 80

2 Ibid 40-41.

3Tony Demark, Crepuscular Rays. http://www.ems.psu.edu/~demark/471/CrepuscularRays.html#scatter (Last Accessed February 19, 2005)

4 Les Cowley, Atmospheric Optics: Rays and Shadows: Formation and Perspective. 12 Feb. 2005 http://www.sundog.clara.co.uk/atoptics/rayform.htm (Last Accessed February 19,2005)
5 Fisher, 68.

6Roald Hoffman, "Thoughts on Aesthetics and Visualization in Chemistry." Preface. Issue on Aesthetics and Visualization. Hyle. 4

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