Why is the sky blue? This is a pretty simple question. It is a question a child might ask, and why not? The sky is right there in full view and it is blue.
Actually, thinking about it, this question can be asked of someone of any age. It certainly was a question of early scientific inquiry. It was Issac Newton who played around with prisms that ushered in the early understanding of color, light and perception: discoveries to build upon. Perhaps I should not say played around with. Sir Issac Newton was a very sober individual who probably wouldn’t have appreciated describing his methodical efforts in such simplistic terms. Nonetheless, the question before us is, why is the sky blue?
Thanks to Issac Newton and countless scientists over the years, we can safely answer the question, why the sky is blue? It is no longer a mystery. It may be a mystery for those who don’t yet know but one can easily look it up or google it.
The explanation is straight forward and easily found. Mystery solved. Usually the explanation goes something like this: As light travels through the atmosphere most of the various wave lengths pass through. The shorter wavelengths, say 450-495 nm, what we would call blue, have a different path, a different relationship. Those shorter wavelengths undergo what is called rayleigh scattering, meaning those wavelengths are absorbed by gas molecules of the atmosphere and scattered about the sky, hence a blue sky. So far this explanation has stood the test of time and has been the standard answer for the question, why is the sky blue?
Despite all the efforts applied over the centuries and the detailed explanations based on solid scientific pursuits, I have found the conventional response somewhat lacking. The more I approach and explore this simple question, the more there seems to be to it. Something unacknowledged and unsaid lingers in the background.
What is it? What is in the background? What is in the background are million of photoreceptor cells in the back of the eye, some shaped like cones, some like rods. It’s the cone shaped cells that respond to the wavelengths that are interpreted as color. This is an alternative response to the question, why is the sky blue? When certain wavelengths make contact with the cones, in this case the 450-495 nm range, the cones sends a message to the bipolar cells which in turn send a message along to the ganglion cells, then through the optic nerve to the brain. In other words, the eye comes into contact with the 450-495 nm wavelength and produces a visual consciousness, a visual experience of the color. As that visual experiences becomes recognizable, the linguistic symbol blue is then associated with that experience. Somewhere, sometime in our human history someone or a group of someones associated the experience with the word blue (or rather the equivalent in some past language.) Since then, the naming has been handed down from generation to generation to us today.
This alternative optical scenario is another way to explain why the sky is blue. In this answer, the blue sky is dependent upon our perception, which is all very scientifically sound. In fact, color is very dependent upon our perceptions because our friend Newton, all those years ago, also discovered that objects do not have intrinsic color. Objects absorb some wavelengths and reflect others. Our eyes receive the reflected ones, hence, we experience color.
In effect, the red Maserati is not really red, the orange orange is not orange and the burnt slice of bread is not really black. It still tastes bad (unless you like burnt toast), but it is not really black. And yes, the sky is not really blue. It is all perception and interpretation: Perhaps an illusion. If we did not have the faculty of perception then there would be no experience of color. On the other hand, if there were no wavelengths to perceive, again there would be no color. In the wider view, perhaps we can see a larger picture: The two explanations are parts of an integrated whole.
This is an interesting proposition to me due to the fact that we are talking not on a spiritual, metaphysical level but on a material and scientific level. Even the physical world speaks to the existence of interconnectedness if we look close enough.
This leads me back to the original question, why is the sky blue? What has peaked my interest in this question is not really the scientific explanations behind it, fascinating and wondrous as they are. What I find compelling is how we leave the element of ourselves out of the explanation.
There is the perceived but no perceiver in these explanations. It is as if the world exists for its own sake and that we are mere bystanders, like mere observers wandering in a natural history museum. We eat, we breath, we walk, we sit in awe, we cry. We are of the universe and the universe is of us.
We did not land here from a distant galaxy or another dimension nor did we just suddenly appear. The story of humanity is the story of the earth which is the story of the universe, of time, of space. Didn’t humanity create science to perceive that which we could not see before? To understand the relationship of it all? This question is not really why is the sky blue, but rather why do we see the sky as blue? Why do we perceive it in a certain way? What is our relationship as the perceiver to the perceived? Are these two aspects actually separate? These questions beg a different answer, an answer about a deeper understanding leading to a deeper meaning and even deeper mysteries. To look to the sky and ask myopically why is the sky blue without a wider view of our own humanity, without a view of our participation in the universe, is a missed opportunity. It is nothing less than a missed-perception.
Window into the Now
Within Buddhism there is the teachings on dependent origination, sometimes translated as interdependent origination. Simply put, as it is often expressed in the early sutras themselves, “if this exists, that exists; if this ceases to exist, that also ceases to exist.” Some began to interpret the teachings of dependent origination as strictly sequential and linear, a force like a row of dominos, topple one and the others will fall in line, one after another (providing you set them up properly).
Later schools of Buddhism, such as the Huayen school, based on the Avatamsaka Sutra, took dependent origination further. All things are not only dependent upon other things for their perceived existence, but everything can be found in everything else. In other words, we exist in an infinite interconnected universe where everything is dependent upon everything else and everything contains everything else.
For example, as I look outside my window at the pine tree, I reflect on how that tree got there, in this case it was planted years ago, and how the rain, sun and soil are present, sustaining its existence. I also see the pine cones. What are the pine cones? Future potential trees. I also see how it helps produce oxygen, a rather important thing for life on this planet and at this moment, my life. As I observe the tree it becomes part of my experience as a conscious being. The teachings on mind show us that consciousness does not happen independently on its own. We are always conscious of something.
What I find most important in all of this is how this teaching and understanding can be accessed in the present moment, just by exploring. So, here are two questions:
1) Looking at your hand can you see a Tyrannosaurs Rex (no, not a plastic toy one)?
2) What does it take for your present moment experience to happen, both in the past and right now?