Secrets of Light

There are truths so obvious that only modernity can mislay them.

One is that light matters. Not metaphorical light, not the sort lifestyle coaches prattle about, but actual sunlight: the old, vulgar, democratic blaze that rises every morning and asks nothing of us except that we step outside.

Richard J. Wurtman, a nutritionist at the Massachusetts Institute of Technology, observed that light may be the most important environmental influence on the body after food. Quite right. We have spent centuries refining sauces and inventing diets while behaving as though the Sun were an optional extra, a decorative lamp fitted to the sky.

Wurtman recommends twenty minutes at noon. Sensible advice. There are dermatologists who would apparently prefer the species to be raised underground like mushrooms, pale and fretful, emerging only under factor-50 and legal indemnity.

Plants know better. They bend, stretch, contort themselves toward brightness with the urgency of addicts. We do much the same, though with deckchairs, beach towels, and Ryanair. Light means warmth, colour, movement, energy. It stirs the chemistry of life, nudges electrons into useful enthusiasm, helps cells make the tiny packets of vitality on which all animation depends.

We are, in a practical sense, creatures powered by radiance.

And there is something faintly miraculous in this: living cells emit minute traces of light themselves. Bio-photons, they’re called – invisible to us, measurable by instruments, little Morse-code flickers from the machinery of being alive. Their patterns change with health and disease. Even our illnesses, it seems, glow differently.

So light is not merely scenery. It is infrastructure. The spinal column of existence. Medicine has tended to reduce this grand relationship to a single nutrient, vitamin D, which is rather like discussing the ocean chiefly as a source of salt. Useful, yes, but comically incomplete.

Older writers understood this with less jargon and more confidence. Herbert M. Shelton wrote that sunlight enriches the blood and benefits every tissue and function of the body. The language is grand, and the instinct sound. People deprived of daylight look it. We become wan, stale, inward, as though stored too long in a cupboard.

In the early twentieth century, Augusta Rollier established solaria in Switzerland – buildings designed to maximise exposure to sunlight. Patients with tuberculosis, lupus, arthritis and other chronic complaints were wheeled into the alpine glare like offerings to Apollo.

The results were often remarkable, or at least remarkable enough that we might wonder why the idea was abandoned in favour of fluorescent waiting rooms and magazines from 2017.

Dr Zane R. Kime argued that those who receive more sunlight suffer less cancer, and that sensible exposure strengthens immunity and oxygenation. The caveat, naturally, is obvious: sunlight is a tonic, sunburn is vandalism.

There is a difference between nourishment and self-harm, though humanity has always shown a talent for confusing the two.

We need light. We crave it. We holiday for it, worship it, write poems to it, and yet somehow hesitate to use it wisely. If you wait for unanimous medical enthusiasm before stepping into the sunshine, you may expire first – if not of cancer, then of committee delay.

Without the Sun, Earth would be a frozen marble rolling dumbly through black space. With it, seas move, winds turn, weather forms, plants grow, oxygen gathers, food appears, and life continues its noisy, extravagant business.

The least we can do, in gratitude, is open the curtains.