This afternoon, I am going to see friends who live about 1 hour's train ride away. It being December, by the time I'll get back, it will be pitch black dark outside, although I am not planning on staying out late.
When we set up our appointment for today, I felt somewhat apprehensive about having to travel back on my own in the dark. And earlier this morning, while I was doing the cleaning, I began to wonder why - there is hardly any difference between leaving work at 6.30 in the evening, when it has been dark for almost two hours already, and taking the train back home on a Saturday night.
It is dark when I get up, and it is dark when I come home, so what's the big deal? Why would I be apprehensive about this train trip and not about the daily one after work?
Admittedly, the general crowd out there tends to be a bit on the rowdy side on a Saturday night, as opposed to any night during the week. But I am not scared of those kids and usually I am invisible to them anyway, being middle-aged, of average-to-ugly looks and keeping quietly to myself.
Why does darkness feel different at, say, 10.00 pm than at 5.00 pm? And different again at 3.00 am?
It is always the same darkness - never really dark here anyway, what with me living in one of the most densely populated areas of Germany, city lights and all.
And yet there is something about our inner clock, I assume, that makes us feel different about being out on our own at different times of the day and night, and year; while I feel a sense of adventure rising in me when I am out during the night in summer, that changes into a sense of danger in winter, and I don't think this is only because of the temperature.
Does that stem from some very realistic sense of danger that our ancestors had, when they were still roaming the savannahs and the sabre tooth tigers would be on the prowl mainly from dusk till dawn?
Or is it to do with our general rhythm of life, active during the day, supposed to be sleeping during the night? And of course, that rhythm must have already been in place quite firmly back then in the savannah, or wasn't it?
Me not being an expert in the evolution of humanoids, I can only speculate.
Maybe one of my precious few readers can enlighten me.