Sometimes when I'm lying in bed trying to get to sleep I mull over some of the great disconcerting mysteries of life, like how my consciousness is actually a collection of cells that somehow interacts to keep me alive, how my existence and personality are the result of one vastly-outnumbered sperm meeting one egg and how I'm a tiny insignificant organism on the surface of an isolated rock adrift in the infinite universe. The thing I try not to dwell on is the fact I'm about to involuntarily lose consciousness for several hours as my body embraces sleep.
Sleep is a remarkable biological phenomenon, a daily necessity which requires us to lose contact with our environment while our bodies refresh. We've all been doing it since we were born and have to continue doing so or face debilitating consequences. Some people have trouble slipping into it but nobody can hold it off forever. Whoever we are and however badly we do it, we have to accept that at the end of the day we will find an appropriate space, embrace an unconscious state and temporarily flicker out of existence.
Our homes are designed around the fact that for maybe a third of the day we will occupy a separate space with minimal external stimulation. We own special items of furniture which allow us to lie horizontally in comfort, helping to maximise the efficiency of our daily downtime. We generally own one of these items each, or maybe one per couple to allow them to double up for other biological activities. If we're ever away from home we pay considerable amounts of money to ensure we have a bedroom for the night because a non-stop seven day holiday isn't physically possible. Sleep is an intrinsic part of our environment and our day.
If hostile aliens ever visited our planet, our need for sleep is one biological weakness they could turn against us. Keep the population awake with a non-stop cacophony of noise and all planetary resistance would fade away before the end of day one, definitely day two. It'd be an easier offensive trick to pull than removing all our oxygen or extinguishing our supply of food. For defensive reasons it's fortuitous that humanity doesn't all sleep at the same time thanks to the rotation of the earth, not to mention the existence of night shift workers, and this is just the kind of random thought that swirls around my brain as I wait for unconsciousness.
The period immediately before sleep is a strange one. You lie there with your eyes closed, thinking... perhaps for seconds, more likely minutes and if you're unfortunate hours. You may never get to the end of what you're thinking about if sleep kicks in midway, or you may continue to have conversations with yourself in a depressingly unhelpful spiral. It doesn't pay to focus too much on the fact you won't remember anything of what happens next, nor that you have no control over what follows, indeed there's always a tiny possibility you won't wake up at the end of it. They say dying in your sleep is the best way to go, and it probably is, but that's never the best thing to be pondering as eyelids fall.
We instinctively trust that sleep is needed every night and have done so since the day we were born. We might do less of it than we once did, and may now have more trouble reaching a switched-off state, but we still submit on a daily basis. Unless we're well read we don't know why we do it, indeed scientists still aren't 100% sure what the precise purposes are, but animal instinct is enough to trust that it needs to be done. It helps that we've all seen others peacefully asleep so we assume the experience can't be too traumatic, but unless someone's gone out of their way to film us sleeping it's the one part of our lives we never see.
Sleep isn't a switch you can flick, at least not without external help like inebriation or a tablet. If we're unlucky we wake several times during the night, and if we're unluckier just the once and never get back to sleep again. The night is a long and lonely time for those who are wide awake when society dictates they shouldn't be. Jolting out of sleep at the end of the night is easier, courtesy of alarm clocks of all kinds, but doesn't always leave us in the freshest frame of mind to face the day. Far better to wake naturally after your body's recharged properly, assuming of course your lifestyle, pets and family permit.
The freakiest part of our nightly slumber has to be our dreams. We dream multiple times each night, in shorter bursts earlier in the night and in longer bursts later on. We only remember our dreams if we wake up during them, and even then their narrative swiftly fades. Many reckon that dreams are our brain's way of filing away memories, but much of what they contain never happened nor ever could. Our conscious mind would swiftly ridicule the storyline for its implausibility - those people never met, she died years ago, that's not a real place, the laws of physics refute this. But while they're underway our senses are entirely absorbed by the ongoing story, however ridiculous, and react to every imaginary stimulus.
Our dreams have plots you couldn't have written and special effects you wouldn't believe. It's like a phantom projectionist sets up in our minds and shows us immersive 3D movies nightly. They might show us a meeting and we feel like part of the conversation. They might show us a car chase and it feels like we're at the wheel. They might introduce some kind of sexual interest and our lower body instinctively responds. They might collapse the floor beneath our feet, shoot us with a weapon or fire us into space and our pulse quickens as we assume it's really happening. I sometimes wonder about the physical and emotional trauma I'm subjecting myself to each night... but only if it happens to wake me up, not the countless adrenaline rushes and raised heartbeats I must have slept straight through.
Sleep is both one of the safest parts of our day and when we're at our most vulnerable. It requires our attention, refreshes the soul and hides the early hours from sight. It's a period when we willingly submit to whatever our subconscious decides to throw at us, and somehow we remember almost none of it. It's a nightly mystery we can't live without but don't fully understand. It likely occupies 20 years of our time on this planet - that's the sacrifice of two whole decades spent lying down with eyes firmly closed. And it's best not mulled over just before you drop off, in case you never do.