I grew up in the southern part of Michigan,where thunderstorms and tornadoes are frequent and epic. Sometimes they are raging, maniacal frenzies of destruction, sometimes gentle electrical stimulations of the Earth’s generative apparatus. While the furious lashings of cataclysm were thrilling and sparked a delightful instinctive reaction at the base of my spine, it was the soft rumblings of intimately murmured thunder that moved my poetic soul. I was always intrigued by the way a discharge of thunder could roll voluptuously about a rural or urban landscape, like a familiar voice, almost purring like a great and ancient cat.
As the thunder’s voice spoke of the ancient marriage of sky and earth, I would follow it with my ears and eyes as it crossed over a field or strolled down a city street, sometimes originating in a high, crackling plaint, to descend in frequency but build in depth and strength, sometimes arising from a quiet basso profundo to a comforting rumble that felt like a squeeze around the middle, only to return to its distant low chanting and dwindle away. Often the voice of thunder moves across the landscape under the sky, crossing away and back again, more than once, meandering like a lost old man, a fully embodied thing, a spirit seeking to and fro for a home.
Such is the poetic reflection of my soul’s response to the being of thunder. But I am also a scientist. So I knew that the embodied being of thunder was an illusion (though no more so than we ourselves are), its material nature being that of a complex series of atmospheric compressions and relaxations. But that complexity of vibration is also not without its poetic vitality.
Thunder results from an extremely high and rapid pulse of temperature variation as trillions of electrons make their exit from an excessively negative region to the more open and positive spaces of uncharged atoms -- a flight to which many of us can relate. Their passing along an established corridor heats and expands a chaotically shaped tube of air, which then, just as suddenly, collapses with the force of thousands of tons of atmosphere. It is a brief, singular, and very local event. Why then, my poetic and scientific minds wondered together, does this event spawn that entity that roams about the countryside, that long chanting voice, that familiar old man, both directionless and purposeful?
That question haunted me a long time. There is a seeming paradox between the instantaneity and locality of the lightning event and the lingering, wandering quality of the thunder. In a simple sense, it is understandable: The instantaneous event causes a lingering disturbance, as a single rock thrown into a pond leaves a lingering disturbance on the surface. This explains the duration of the thunder, but not its character. The ripples on the surface of the pond have a particular character, a pattern of concentric rings, easily recognized in any context, that is a product of the properties of still water (its surface tension, density, viscosity, etc.). What was it about the atmosphere that produced the singular character of thunder? And what is more, why is it that, although ripples on a pond are everywhere mostly the same, every stroke of thunder seems a unique individual, a snowflake, a signature, a fingerprint, never heard just so before, and never to be heard just so again?
Students in my mathematics classes have become accustomed to my tangential divergences from the subject at hand. I like to think they also, eventually, come to appreciate that these divergences are never random, but always connect in some way, though perhaps not obviously, to the matter under consideration. The superficially digressive nature of my dialog with them about mathematics is simply a reflection of the interconnectedness of all things. What do the Taoist stories of Lieh Tzu have to do with the irrational solutions of quadratic equations? Why, everything, students. Everything.
But those who have not sat or stood or wandered about in my mathematics classes (or science, or history, or literature… just what class is this, anyway?) will have to learn patience and trust that it all connects back together.
There is a man who can echolocate like a bat.
His name is Daniel Kish. Blind since 13 months because of retinal cancer, he began at an early age to click with his tongue. Listening to the way the click echoed about a room, Kish could understand things about his environment: Is there a wall nearby, is the room large or small? The more he clicked and listened, the more Daniel Kish derived information about his surroundings. Is the door open or closed? Are there people in the room? He began to detect finer and finer objects,and became able to detect an object as thin as a 3 inch diameter pole at a distance of several feet. Eventually, Daniel Kish was able to play ball and ride a bicycle using his clicks to create an image of the world around him. This is exactly the process used by bats, dolphins, other toothed whales (such as orcas) and a few species of bird to navigate in a dark or murky environment. Kish not only navigates by echolocation himself, he teaches the skill to blind children, through his organization, World Access for the Blind.
Daniel Kish’s ability seems inconceivable at first glance (google the name to find many striking demonstrations, including an excellent TED talk). Yet it turns out that latent echolocating ability in humans has a neurological basis (see, e.g., http://blogs.plos.org/neuroanthropology/2011/06/14/getting-around-by-sound-human-echolocation/). Further reflection only amplifies the plausibility of human echolocation. Dolphins are genetically similar to humans, and have intelligence and sociability that compare to human traits. Indeed, nearly all of the echolocating animals are mammals like us.
Neurological work such as that referenced above shows us that it is not only neural inputs from the eyes that stimulate the visual cortex of the brain. In fact, sounds with echoes stimulate the visual cortex of sighted people, and much more so in the blind who have trained in echolocation, like Daniel Kish. So, as Kish says, vision is much more than sight. In fact, Kish describes the experience of echolocating in visual terms, saying that it is “like lighting a match in the dark.” (http://www.worldaccessfortheblind.org/).
So, all of us are capable of echolocating. Our visual cortex is stimulated by the texture of an echo, contributing to our image of our surroundings. This is not surprising to me. Another phenomenon that has always fascinated me is the way a sound changes as it moves through the environment. I notice how a lawnmower that moves toward and away from a barn wall changes its timbre in the same way as an electric guitar played through a flanger -- an electronic effect that creates a tiny echo, and varies the length of the echo over time. I also notice how the sound of an impact-head water sprinkler changes as I walk across the lawn, thus changing my spatial relationship to the sound source and to the objects in the environment. As I reflect on this fascination, I note that a lawnmower and a sprinkler both emit short bursts of sound at regular intervals.
My wife is a dancer. She never gets lost. I’m a mathematician. I get lost driving to the same grocery store I’ve been to a dozen times, even though it is nearby. As a dancer from a very young age --practically from infancy -- Tamara has a highly developed sense of place and position, rooted in the vestibular sense of the brain-body system. I not only lack a well-developed vestibular sense (and thus am a terrible dancer and get lost a lot), but also have had poor vision since infancy. My extreme myopia was not noted until I was six years old. Is it possible that my fascination with sound and its relation to the environment is rooted in a glimpse of echolocation that I developed in childhood as a compensation for my visual and vestibular deficiencies?
My fascination with sound and its relation to the environment. That brings us back to the topic at hand. Which was thunder, in case you forgot. Early in my musings on thunder, I had begun to hypothesize that the duration, character, and sonic texture of thunder arises from a series of echoes of the original clap, echoes that reflect off various large-scale objects in the environment: trees, hills, buildings. The initial clap is a short burst of sound with a white spectrum: It contains an equal mix of nearly all frequencies, including those above and below the range of human hearing. It is very short. A first echo occurs as the soundburst reflects off trees and buildings near the original clap, the narrow physical location of the torrent of electrons. Later echoes occur off more distant objects. Sound loses power as the inverse square of distance, but the power of sound is also inversely proportional to the square of the frequency. So low frequency sounds have more power and travel farther and through more objects than high frequencies (which is why, from outside the car of someone who is rocking out to the Foo Fighters, you hear only the bass). So as the sound travels farther, the higher frequencies drop quickly below audible power. The frequencies with the longer path to travel take longest to reach your ears. Thus, a nearby thunderclap begins with a mix of frequencies, but the average frequency drops over time, as more distant echoes reach your ear. For distant thunder claps, only the lowest frequencies reach your ear, and they have all traveled very different paths as they reflect off many distant objects, so the sound begins in a low rumble, seems to change location a lot,then quietly attenuates in a bass decrescendo. So there. I had explained some coarse features of the sonic envelope of thunder. It is accurate, insofar as it goes.
But Daniel Kish just gave me a much richer understanding of the texture of thunder that blew my coarse analysis out of the sky. Kish says we can use a short sound burst and the texture of its echo to create a complete visual image of our surroundings. My long-term fascination with the texture of sound, coupled with my early poor vision and general lack of spatial orientation have stimulated in me a particular responsiveness to that image. It is an image that exists not just in the imagination or in the poetic soul, but in the visual cortex. It is something we see. “Vision is not in the eyes, it’s in the mind,” says Daniel Kish. When I hear thunder, I see an image of the landscape around me. As the flash of lightning briefly illuminates a dark sky, so the clap of thunder illuminates -- insonnates -- the landscape surrounding me. Not only that, but,unlike light, sound travels through and around objects. The sound I am hearing contains a three-dimensional image of a landscape that is somewhat transparent. It is the singular beauty of that ephemeral image that explains my fascination with thunder, my perception of it as a character, a movement, an embodiment.
The poetic soul anthropomorphizes, reifies, deifies. The rational and scientific mind tend to dismiss these processes as delusion, projection, and wish-fulfillment. But are they? What is the human that is the image of anthropomorphism? A human being is a complex of chemical and electrical processes that take place within a spongy bag of seawater. Yet we are this soul, we are this ego, this person, this spirit, this being in relation to other beings. If we allow this anthropomorphized, reified, and deified conception of ourselves, then are we so wrong to ascribe it also to natural entities as defined and romantic as ourselves? Shall we not see the living, conscious, godly entity that lives in the forest, the stone, the sea, the flock, and the thunder?
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