Starless Sky

If the three wise men were to travel on their camels to the stable in Bethlehem this year, they would almost certainly get lost. Along vast tracts of their route, they would be unable to rely upon their guiding star, for the simple reason that it would not be visible. Baby Jesus would have to forego his gold, frankincense and myrrh.

A paradox characterises our society: we know more about the universe than ever before – we know why the stars shine, how they are born, how they grow old and die, can perceive the swirling motion of galaxies invisible to the naked eye, listen (so to speak) to the sounds of the origin of the universe emitted some 15 billion years ago. Yet for the first time in human history few adults can recognize even the brightest of stars, while most children have never witnessed a starry night. I say most because the majority of the world’s population today – now surpassing 4 billion – live in urban areas, where artificial light obscures the stars from view.

(This is a form of contradiction common to modern life. The moment we are able to satisfy our desire to fly across the world to exotic beaches and get a tan, the hole in the ozone layer makes the ultraviolet rays of the sun dangerous and carcinogenic. As soon as we realize our desire for cleanliness – see my previous article on eliminating odours – water becomes a limited resource, and so on.)

The awesome spectacle of the star-filled sky is quite unknown to most of us today. Rarely do we raise our gaze to the skies, and if we did, we would see only a handful of dull glimmers of light. To think than on a clear night in ‘normal’ darkness as many as 6,000 celestial bodies are visible to the naked eye, the furthest being the Triangulum Galaxy, some 3 million light years away (we see it as it was three million years ago). And this is nothing compared to the many billions whose existence observatories and telescopes have revealed to us, as our eyes have become ever more blinded by artificial light.

In Darkness Manifesto (2022), the Swedish writer Johan Eklöf tells us that in Hong Kong (together with Singapore the most illuminated city in the world) the night is 1,200 times brighter than without artificial lighting. To realise the enormity of the transformation, you only have to look at this map which records light pollution (you can zoom in and see the situation where you live). In 2002, the amateur astronomer John Bortle devised a scale which measures the darkness of the night sky: level 1 corresponds to an ‘excellent dark-sky’, level 3 ‘rural sky’, level 5 ‘suburban sky’; at level 6 (‘bright suburban sky’) only 500 stars are visible to the naked eye; at level 7 (‘suburban/urban transition’) the Milky Way disappears. At level 8 (‘city sky’) and 9 (‘inner city sky’) only a few celestial objects are visible (nearby planets and a few clusters of stars).

A case could be made that artificial lighting is the industrial innovation which has most profoundly affected human life. It won the multi-millennial war against darkness, driving away the terror of the night; its nightmares and its monsters. Only a few centuries ago, when night fell, not only homes but entire cities were barricaded, their gates bolted. The night was populated by demons (Satan, of course, was the ‘Prince of Darkness’); it was the time when the forces of evil gathered, when witches celebrated the Sabbath riding pigs or other animals, as Carlo Ginzburg recounts in his Ecstasies: Deciphering the Witches’ Sabbath (1990).

Illuminating cities has been a practice for over three centuries, long preceding the invention of electrical lighting. Ancient Romans knew night lighting, but a millennium would pass before oil lamps appeared in city streets. It is perhaps no coincidence that the Enlightenment was coeval with urban lighting; its definition of the ‘Dark Ages’ may not have been simply a metaphor. In Disenchanted Night: The Industrialization of Light in the Nineteenth Century (1988) Wolfgang Schivelbusch details the ‘chemical enlightenment’ brought about by Antoine Lavoisier’s modern theory of combustion, according to which flames are not fuelled – as has hitherto been assumed – by a substance called phlogiston, but by oxygen in the air. It is with this that the modern history of artificial illumination begins. ‘The light produced by gas is too pure for the human eye, and our grandchildren will go blind’, Ludwig Börne feared of gas lamps in 1824. ‘Gas has replaced the Sun’, Jules Janin wrote in 1839. Illumination was also a means of control: the first target of the revolutions of 1830 and 1848 were the street lanterns. A new profession appeared: the lamplighter, who becomes a literary figure, as in Andersen’s ‘The Old Street Lamp’ (1847) and ‘The Lamplighter’ (1859) by Dickens. Saint-Exupéry’s Le Petit Prince (1943), upon arriving on the fifth planet, encounters only a streetlamp and a lamplighter:

When he landed on the planet he respectfully saluted the lamplighter.

‘Good morning. Why have you just put out your lamp?’

‘Those are the orders’, replied the lamplighter. ‘Good morning.’

The carbon filament lamp that Thomas Edison presented at the Exposition Universelle in Paris in 1878 swept away gas lighting, and became the new artificial sun, just as blinding as its natural counterpart. Schivelbusch cites the following medical text from 1880:

In the middle of the night, we see the appearance of a luminous day. It’s possible to recognise the name of streets and shops from the other side of the street. Even people’s facial expressions can be seen clearly from a great distance and – of particular note – the eye adjusts immediately and with the least effort to this intense illumination.

With electricity, humanity conquered the dark. Mealtimes shifted, as did those for socializing, for entertainment, for work – the ‘night shift’ became possible. A new rhythm now regulated daily life, one in conflict with our circadian one (a term derived from the Latin circa diem, ‘around the day’).

By making the night disappear, we alter the rhythm with which hormones are produced, in particular melatonin, which regulates the sleep cycle, and is synthesised by the pineal gland in absence of light. When darkness falls, its concentration in the bloodstream increases rapidly, peaking between 2 and 4 am, before gradually declining before dawn. Thus long periods of high melatonin levels are normal during winter months, while the opposite is true in the summer, when days are longer and brighter. According to the website Dark Sky, melatonin has antioxidant properties, induces sleep, boosts the immune system, lowers cholesterol, and helps the functioning of the thyroid, pancreas, ovaries, testes and adrenal gland. It also triggers other hormones such as leptin, which in turn regulates appetite.

Nocturnal exposure to artificial light (especially blue light), inhibits the production of melatonin. A brightness of only eight lux is enough to interfere with its cycle. This is a direct cause of insomnia, and therefore also of stress and depression and, through the deregulation of leptin, of obesity. Certain studies show that night shifts increase the risk of cancer (melatonin and its interplay with other hormones help prevent tumours). It’s therefore understandable that artificial lighting has generated the term ‘light pollution’.

This much concerns us humans. But the effect on other living beings is far more dramatic – after all we’re diurnal animals. As Eklöf writes, ‘no less than a third of all vertebrates and almost two-thirds of all invertebrates are nocturnal, so it’s after we humans fall asleep that most natural activity occurs in the form of mating, hunting, decomposing and pollinating’. The prey of nocturnal predators has far less chance of escape. Today elephants, who are also diurnal, are said to be becoming nocturnal in order to evade poachers. Toads and frogs croak at night as a mating call; without darkness their reproductive rate plunges. The eggs of marine turtles hatch on beaches at night; the hatchlings finding the water by identifying the bright horizon above it. Artificial light thus draws them away from it: just in Florida, every year this kills millions of newly-hatched turtles. Millions of birds die every year from colliding with illuminated buildings and towers; nocturnal migratory birds orient themselves with the moon and the stars, but are disoriented by artificial light and lose their way.

The worst effects are felt by insects. According to a 2017 study, total insect biomass has dropped by 75% in the last 25 years. Motorists have been aware of this for some time, through the so-called windscreen effect. The number of insects that get squashed on the front of cars is far smaller than in previous decades. There are many causes for this decline, but artificial lighting is certainly one, because the majority of insects are nocturnal. We don’t realize it, but illuminated cities are a major migratory destination for insects from the countryside. Light also disturbs their reproductive rituals. Moths are exterminated by their attraction to light, and more plants are pollinated by moths than bees (which are also declining). The problem of pollination is so serious that, as Eklöf recounts, a few years ago photos of an orchard in Sichuan showed workers with ladders pollinating flowers by hand. Working quickly, one might be able to pollinate three trees a day; a small beehive can do a hundred times that number.

A further side-effect of artificial lighting is that non-lit areas become even darker, because it takes time for the eye to adjust and reactivate the rods (which are sensitive to the intensity of light) and deactivate the cones (sensitive to colour) in the retina. The human eye is one of the most precise senses, capable of perceiving a single photon. It has been calculated as equalling a 576-megapixel camera. At night, when our eye has adjusted to very low levels of luminosity, we’re able to see quite a lot. With the full moon, we’re capable of walking briskly along a rugged path. But artificial light blinds us to everything that we would have seen with ease in earlier periods. Here is another case of the technological revolution simultaneously giving and taking away.

Light pollution has today created a market for darkness tourism; the hunt for (by now rare) places where darkness is total. Great sums can be spent in search of what we have gone to such lengths to defeat. As Paul Bogard tells us in his The End of Night: Searching for Natural Darkness in an Age of Artificial Light (2013), to find darkness in Las Vegas one has to go all the way to Death Valley. One of the darkest places on the North American continent, there, Bogard writes, the light of the Milky Way is so intense it casts shadows on the ground, while Jupiter’s brightness is strong enough to interfere with his night vision. It was in the Atacama desert, one of the darkest places on earth, that in 2012 Noche Zero, the first global conference in honour of darkness was held, attended by astronomers, neurobiologists, zoologists and artists.

A community of ‘lovers of the dark’ has thus formed, with its own cult books such as Junichiro Tanizaki’s In Praise of Shadow (1933), a veritable eulogy to the penumbral; its groups such as the International Dark Sky Association, founded by a handful of American astronomers in 1988; and its sanctuaries, parks and reserves. They cite studies according to which, rather counterintuitively, the lighting of roads can decrease safety by making victims and property easier to see. Theirs is a noble fight, though one with doubtful prospects for success, given the hunger for light that consumes our species. Speaking of consumption: LED bulbs consume far less energy than filament ones, and for this reason far more of them are used, increasing total light emission. It has been calculated than in the US and in Europe unnecessarily strong or badly directed lights (which are pointed at the sky, or other spaces that don’t need to be lit) generate emissions of carbon dioxide equal to that of 20 million cars. And every year the illuminated portion of the planet grows inexorably. I realize it’s banal to do so, but I can’t help but think of those two things which for Immanuel Kant ‘fill the mind with ever new and increasing admiration and awe, the more often and steadily we reflect upon them: the starry heavens above me and the moral law within me’. Could he ever have imagined the sky above us no longer filled with stars? We might ask if the moral law within us is also waning, or if it has already been lost.

Translated by Francesco Anselmetti.

Read on: Carlo Ginzburg, ‘Witches and Shamans’, NLR I/200.