The Earth is bathed in a flood of sunlight. A fierce inundation of photons: 342 joules per second per square meter. And these are just the lucky few who have spent ten thousand years struggling to free themselves from the vast pressures of the solar core: inching their way to the surface before light-speeding eight minutes through outer space to impact here and now on the surface of the ocean and the back of your eye.
Not all light. Reflect this received sunlight through a glass prism, as Joseph von Fraunhofer did, and you will see dark patches in the spectrum: gaps in the light. These lines correspond to the absorption spectra of certain molecules in the photosphere, the outer layer of the sun. Photons, on the very point of escape, colliding with free-floating oxygen, helium, mercury, and magnesium atoms, and being re-absorbed. They show telluric contamination too: water vapor and industrial gases in the Earth’s atmosphere block and bounce back the light. It takes 4,185 joules – one calorie – to raise the temperature of one kilogram of water by one degree C. If all the photon energy streaming from the sun were captured by the Earth’s atmosphere, its temperature would rise by ten degrees C in one day. So all that telluric dust and fog is no bad thing; indeed, we might make some more of it, the right kind, just to bounce some of it back and keep it cool down here. Scatter salt crystals in the sky, form clouds, reflect light. Write a new atmosphere.
But that isn’t even half of it. For all that light, we live in such a narrow band of the electromagnetic cosmos. From 380 to 740 nanometres: the visible spectrum, from blue to red, and beyond that – to us – a darkness, yet filled with infrared, ultraviolet, X and gamma rays, micro- and radio-waves, perceptible only by specialized instruments, cameras with their anthropomorphic IR filters removed, certain kinds of squid and shrimp. (Snakes “see” in the infrared, plants signal to one another with ultraviolet pulses we are only just beginning to decode.)
The light impacting on the back of your eye was born a hundred thousand years ago in the heart of the sun, when humans were first placing one stone upon the other, before we learned to daub or write or even speak.
We mostly think of ourselves limited by our spatial and temporal bounds. We, six feet high at best, can see a few miles from a peak, live four score and ten years if lucky, and so on. Our spectral capabilities are limits too: a tiny slice of the universe, easily overwhelmed by noise, interference, conflicting frequencies. Our very ability to know is so constrained, so unimaginably meager in the grand scheme of possible knowledges, of sights and senses, and yet we experience it as an overload, a glut, a constant battle, a tragedy, a failure to comprehend and act fully. We are all too easily overwhelmed by light, despite the little of it we really see: the white-out, the sunburn, the melanoma, the sheer weight of knowledge and experience that full exposure to contemporary enlightenment brings down with it, ceaselessly flowing from the sky.
Awareness of these restraints makes us chafe against them. We have developed tools, technologies, to ameliorate and deny them. Hulls, wheels, and wings, even (borrowed) hooves to move us (if only we could see through horses’ eyes as easily as we can saddle them: 350 and better in the dark). Medicines that stretch out lifetimes; soon, gene therapy to remake living cells anew. And so too tools for manipulating light and tools for capturing it: polished lenses, tele- and micro-scopes, silver halides, fiber optics, quantum calculators.
These latter tools are becoming as risky and potentially injurious as all our others. Our current most popular methods of locomotion spew black carbon and other noxious gases in the streets and into the upper atmosphere, billowing from exhaust pipes and jet engines. Antibiotic resistance threatens to encourage the rise of new, unconquerable superbugs, while hormones and mood stabilizers leach into the water supply, reduce fertility, cascade through fish and insect bodies. And light, life-giving, photosynthesizing, illuminating, fixed on photographic paper and celluloid, snaffled by CCDs, fed into the fiber optic infrastructure of knowledge production, becomes another manipulable medium, becomes big data and fake news, becomes cognitive collapse, becomes its opposite. Light pollution affects not only our vision, but our very ability to think.
The essence of light is not revelation, not eternal truth or verity, not the fixed image of the photograph, but the flickering frames of the cinema.
We must reconstruct not only our industry, our biochemistry, our politics and our relationship to the natural world, but our way of seeing the world. In the coming decades, we will learn to harness light in new and necessary ways. The price of photovoltaic – solar panels – falls year on year, precipitously. Do we use these newly cheap photons to maintain our current, eminently unsustainable and exploitative lifeways, or do we understand them as a call to redistribute knowledge and power meaningfully and practically: teach engineering skills, build local battery farms, set up energy co-operatives, share our resources? Changes in technology always and already necessitate changes in society, and so we ask the question we always have to ask: what, how, and for whom?
And as image-makers, writers, programmers of machines, educators, people who see, we have to ask: what, in this age of overexposure, is the role of art? What stories can we tell that encompass the whole planet, and the sun, the streams of photons and rivers, the ocean currents, the rising sea levels, the forests and their inhabitants, the turn from global to terrestrial, the borders and their breaking down? Stories of change, of which light is the best teacher. The essence of light is not revelation, not eternal truth or verity, not the fixed image of the photograph, but the flickering frames of the cinema. It is shift, flux, fusion, and emission. It is radiation and diffraction; the expansion of the circle and the dappling and interference of the grey area, the uncertain, the unpredictable. The light impacting on the back of your eye was born a hundred thousand years ago in the heart of the sun, when humans were first placing one stone upon the other, before we learned to daub or write or even speak. The same light scatters in the sky and glitters on the sea, it shimmers and vibrates, and we shimmer and vibrate with it. We do not directly perceive the world, rather we absorb it second by second as the impression of a billion wave-particles, endlessly reflected and retransmitted, that make us up too. As we are reconfigured by light, so we shall reconfigure the world.
Postface written by James Bridle for the 2019 Overexposure catalog edition.