It is one of those things that divide people into two classes, like Marmite or Proust or Wagner. You look at a picture of the earth seen from space at night and your eyes swing straight to the places that glow: Europe and the right-hand side of North America, bright bits in South America, the bottom of Africa, a lot of India, East Asia, especially Japan.
But Africa from the Sahara to the Zambezi is black, along with the Amazon Basin, the poles and most of Australia. New Guinea is almost invisible. So – where do you want to be? Safe in the light or venturesome in the dark? I suspect this is also a question that divides individual people in half: parts of us thrill to the dark even as we long for the light.
On Tuesday 21 December at 15:58 the northern hemisphere will reach the farthest extent of its annual wobble away from the sun. On that day Inverness will get no more than six hours 35 minutes of daylight; London will get seven hours 50 minutes.
The December solstice brings with it the most heartfelt and widespread celebration of the year:
Together we celebrate our belief that light will conquer the darkness, as it does, in the end, every year. We have made the blackest time our season of hope.
The history of humanity is about the quest for light. This is the great metaphor for religion: the true light that lighteth every man that cometh into the world, the sudden enlightenment that comes to students of Zen, the heatless light of God in Islam. But we have also spent our history looking for light in the most literal sense possible.
It began with the control of fire, for the first benefit of fire was not warmth but light: light by which you could see your enemies coming, human and non-human, light to banish fear. It’s been suggested that humans were controlling fire two million years ago; there is hard evidence that they did so at least one million years ago.
Making fire is not hard. You need a flat piece of fairly soft wood, and a spindle, say two feet long, of hard wood. You drill down into the platform with your spindle, turning it briskly while pressing down hard with your hands. In a remarkably short space of time you have smoke, and then tiny coals as pieces of the softer wood, heated by friction, flake off and glow. You tip these coals onto combustible material – the sun-dried dung of elephants is best – and blow gently. And you have flame. You have light.
You have reprised the first verse of Genesis: God said, Let there be light. And it was light – artificial light, made and controlled by the makers of that light – that changed the world and changed our species: the rest of history has been a refinement of that principle. Lamps were invented about 70,000 years ago. By this time the secondary use of fire – warmth – had allowed humans to spread into places with less forgiving climates.
Light banishes fear, but its second gift is time. Chimpanzees, our nearest relatives, live in the tropics and so they have 12 hours of light in the course of a single day; the rest they sleep. Once humans could strike a light, they had several more hours available to them. Time in which they could sing, worship, feast, play and socialise. Time away from the daily search for food, time in which they could start to become a different kind of species.
Many things burn. Grease and oils from cooking animals and some plants will burn, and it was a small step to gather such stuff and burn it on purpose: to fill shells, horns and modified stones with grease and then add a wick made from twisted fibres of hair or dried grass – and you have a lamp, a light that will shine in the darkness for hours. The lamps became more sophisticated: pottery, alabaster, metal. The Romans made closed lamps in two parts, from terracotta, and made a huge version of this for circuses: floodlit sport, no less.
Candles, like most of these great human developments, were invented many times in different places. This involves the burning of a solid rather than liquid: tallow made from the fat of beef or mutton, fitted with a wick. Beeswax was used for a premium product, and beeswax candles were burned in churches. The Paschal candle – the first light of the great Easter Mass – is celebrated in the Catholic Church with a chant that praises both candle and the bees that made it: “a solemn offering, the work of bees”. Paraffin wax, used today, is a more recent invention. In the Dark Ages, when oil for lamps was hard to get, candles were the most important source of artificial light in Europe.
But lamps came back into widespread use when oils became easier to obtain. By the 18th Century, the oil lamp as we normally understand it – a closed container with a ratcheted wick and a glass chimney – was standard, burning olive oil, tallow and fish oil.
There are three drawbacks to this. The first is that these lamps are dangerous: when they fall and break they set fire to everything around them. The second is that they fill enclosed spaces with smoke. And the third is that they stink: burning fish oil or tallow derived from cattle doesn’t create a sweet atmosphere.
This last drawback, along with the human passion for inequality, drove the need for a premium product, and this was oil that came from the great whales. Whales were hunted not for food but for light: especially light for the rich. Best of all was spermaceti: oil from the head of a sperm whale, which burned long and bright and sweet.
Sperm whales use the stuff for the exquisite system of sonar that they used to negotiate the depths: humans found it makes a nice oil to burn – and that’s why Moby Dick, a sperm whale, was hunted with such enthusiasm.
It was all very fine while it lasted, but by the 1850s whale oil had doubled in price because of the overhunting of whales. A decade earlier a Canadian geologist named Abraham Gesner had refined kerosene, which is not only brighter but cheaper. By 1860 there were 33 kerosene plants established in the United States. Artificial light was democratised and industrialised.
The quest for stuff that burns and gives light continued to direct human endeavour. Lamps that burned coal gas were developed in 1784, and were used for street lighting. It was a new technology: it wasn’t the flame of burning gas that gave the light: the gas flame heated a refractive non-combustible substance: the higher the temperature, the brighter the light. By 1880 gas lamps were using cotton threads impregnated with thorium and cerium salts.
Darkness is dangerous. At least, it is to humans: like most primates we have very poor night vision, and very little sense of smell to help. Humans created cities in which people could live and work and study and socialise by night: but getting from one place to another was difficult, for you could easily miss your way, and bad-intentioned people could take advantage of you.
In his diary, Samuel Pepys is always up for it when there is a cloudless night and a good moon, for it meant he could sit up late and still get home in safety: “here we eat and drank and stayed till 9 at night, and so home by moonshine”. You could lead a different sort of life under a full moon.
Street lighting has been an important matter as long as we have had cities. Roman slaves tended lamps outside villas. Link boys were employed to escort travellers with lights through medieval cities. As early as 1417 the Lord Mayor of London ordered all houses to hang a lantern outside in winter.
In Paris by 1588 a torch was burned at every intersection. Louis XIV was very keen on lit streets, and there were stiff penalties for damaging sources of light: by the end of the 17th Century Paris had 2,700 street lamps and by 1730 twice as many, requiring the brilliant invention of the lamppost. Gas lighting was established in Pall Mall in London in 1807, and the pioneer city of Preston was gas-lit by 1816. Now we had cities that glowed.
But that was only the beginning. Next came the invention of lights that could be powered by electricity. Thomas Edison took out his patent on the electric lightbulb in 1878. Electric lighting could be used indoors and, when protected from the weather, out.
Electric lights now come in the three types. The incandescent lamp has a filament that is heated to become white hot; the modern bulb, using a coiled filament of tungsten, uses three per cent of the energy supplied to produce visible light; most of the rest goes in heat. Gas discharge lamps run electricity through gas, like fluorescent lights; LED lamps operate by means of a flow of electrons.
The technicalities improved in street lighting, so that one failed lamp did not put the rest out. There was a breakthrough when all street lights could be controlled centrally; one of my earliest memories is the lamplighter, cycling through the streets with a long stick over his shoulder, lighting each individual lamp.
After the second world war there was a move towards low pressure sodium lamps which used a comparatively little power and had a long life. But the light they emit is unpleasant – “they even fug up the spectrum” complain the clever schoolboy in Julian Barnes’s Metroland – and we see better under white lights, especially in peripheral vision, and that makes driving safer. Sodium lighting was gradually replaced by other forms.
The idea of doing without light horrifies us. Even 12 days after Storm Arwen struck Britain there were more than 9,000 homes without power. The classic horror story of city life without light is that of the Great New York power cut in late December 1977. The city was in the middle of a financial crisis and its nerves were on edge with the Son of Sam murders. In the 25 hours without lights there were 1,037 fires, 1,616 shops damaged, 4,500 arrests and US$300 million in damages, estimated at US$1.3 billion in current terms. It’s been conjectured that hip-hop music was invented on DJ equipment stolen in the darkness. The idea that the power cut was followed by a baby boom nine months later is, quite literally, an urban myth.
We have used the best of our ingenuity and our resources to combat the darkness: and we have succeeded not wisely but too well. There are, it’s been estimated, 350 million street lamps worldwide: 70 per cent of them are powered by fossil fuels. Most of the world – 83 per cent of the population – lives under a light-polluted sky; 23 per cent of the land across the world is affected by sky-glow. This enthusiasm for artificial lights compromises human health and disrupts ecosystems.
Outdoors, lights are not just a safety measure: they are also used for advertising, car-parking and sport. Different countries have different standards: cities in the US emit three to five times more light than those in Germany.
The International Dark Sky Association points out that we operate with a higher light than is necessary: that the level of artificial light is not based on vision science, that much light is ill-directed, that daylight-level lighting is unnecessary, and that many lights are not on timers. Most of this could be easily enough rectified. But it isn’t.
Research in 2016 revealed that one third of the people in the world can’t see the Milky Way, including 80 per cent of Americans and 60 per cent of Europeans. This incessant self-willed bombardment of light leads to worker fatigue, stress, headaches, anxieties and a tendency to have less sex. There are links with night-shift work and cancer. We demand incessant light while our circadian rhythms need a period without it.
Away from humans this excess of light affects nocturnal life, confusing navigation for both long-distance migration and the makers of short-term nightly journeys. It affects their ability to live normally and so reproduce successfully. It has affected predator-prey relations.
Heavy light around lakes prevents zooplankton – small blobs of animal life – from eating algae; the resulting algal bloom kills plants and affects water quality. Night-blooming flowers that depend on pollination by moths are finding it hard to reproduce. The United States Fish and Wildlife Services estimated that up to five million birds are killed annually by being attracted to lights on tall buildings, and fear the actual number may be up to ten times higher.
Holman Hunt painted Jesus as the Light of the World. The 18th-century divorce between religion and science is called the Enlightenment. We know, deeper than we know almost anything else, that when there is light the evil things will vanish: the troll will turn to stone, the vampire will lose his powers, Aslan will come to life on the Stone Table, we will escape from the Dark Side, we will no longer be subject to the ring that in the darkness binds them, there will be a light to lighten the Gentiles and we will be able to live enlightened lives and our never-ending days will be filled of sweetness and, of course, light.
Because of those things – matters that lie far beyond any rational thought we will ever have – we are turning our planet into a place of perpetual daylight in which we can see everything except what ails us. We humans may have made a few mistakes in the way we have managed the life-support system that we call the Earth: but we can console ourselves with the thought that at least we now have a planet that glows in the dark.
Image by Craig Mayhew and Robert Simmon, NASA GSFC.