Robert Macfarlane, The Wild Places
(London: Granta Books, 2007), pp. 192-194:
Noctambulism is usually taken to mean sleepwalking. This is inaccurate: it smudges the word into somnambulism. Noctambulism means walking at night, and you are therefore etymologically permitted to do it asleep or awake. Generally, people noctambulise because they are in search of melancholy, or rather a particular type of imaginative melancholy. Franz Kafka wrote of feeling like a ghost among men — 'weightless, boneless, bodiless' — when he walked at night.
I had found another reason for being out at night, however, and that is the wildness which the dark confers on even a mundane landscape. Sailors speak of the uncanniness of seeing a well-known country from the sea; the way that such a perspective can make the most homely coastline seem strange. Something similar happens to a landscape in darkness. Coleridge once compared walking at night in his part of the Lake District to a newly blind man feeling the face of a child: the same loving attention, the same deduction by form and shape, the same familiar unfamiliarity. At night, new orders of connection assert themselves: sonic, olfactory, tactile. The sensorium is transformed.
Associations swarm out of the darkness. You become even more aware of landscape as a medley of effects, a mingling of geology, memory, movement, life. The landforms remain, but they exist as presences: inferred, less substantial, more powerful. You inhabit a new topology. Out at night, you understand that wildness is not only a permanent property of land — it is also a quality which can settle on a place with a snowfall, or with the close of day.
Over the past two centuries in particular, however, we have learned how to deplete darkness. Homo sapiens evolved as a diurnal species, adapted to excel in sunlit conditions, and ill-equipped to manoeuvre at night.
For this reason, among others, we have developed elaborate ways of lighting our lives, of neutralising the claims of darkness upon us, and of thwarting the circadian rhythm.
The extent of artificial lighting in the modernised regions of the earth is now so great that it produces a super-flux of illumination easily visible from space. This light, inefficiently directed, escapes upwards before being scattered by small particles in the air — such as water droplets and dust — into a generalised photonic haze known as sky glow. If you look at a satellite image of Europe taken on a cloudless night, you will see a lustrous continent. Italy is a sequined boot. Spain is trimmed with coastal light, and its interior sparkles. Britain burns brightest of all. The only significant areas of unlit land are at the desert margins of the continent, and along its mountainous spine.
The stars cannot compete with this terrestrial glare, and are often invisible, even on doudless nights. Cities exist in a permanent sodium twilight. Towns stain their skies orange. The release of this light also disrupts habits of nature. Migrating birds collide with illuminated buildings, thinking them to be daytime sky. The leaf-fall and flowering patterns of trees — reflexes controlled by perceptions of day length — are disrupted. Glow-worm numbers are declining because their pilot lights, the means by which they attract mates, are no longer bright enough to be visible at night.