Moonlight
Today I went on my weekly bike ride. As has been happening all too frequently lately, I misjudged the distance and got caught by sunset while I was still riding. When this happens, I usually strap a light to my forehead so that I can see the lines on the road. (I had flashing lights on my handlebars and backpack, but they are to make sure others can see me; they don't work to help me see where I am going.) Today I was lazy, and decided to wait until it was too dark to see before strapping on a headlamp.
The funny thing is that although it definitely got dark once the sun set, it was never so dark that I could not see the painted lines on the road, or distinguish the road from the gravel shoulder. At first I thought this was because I was getting enough ambient light from the farms and houses I passed as I cycled. But I could see even when there were no building lights in sight. Then I realized that the sky was clear and the moon was full, and I was able to navigate by this light alone.
If there is a theme to this entry it is that intellectual knowledge is quite different from experiential knowledge. I had read lots of stories where characters had used moonlight to navigate their paths, but being a city-dweller I had never done so myself, and I guess somewhere inside I did not believe it was possible in this modern world. But it is, and I experienced it.
The light of the moon is much dimmer than the sun even at sunset. Although I could see the lines on the road and make out shapes around me, I could not distinguish colors well, and I could not read street signs. The moonlight was immediately washed out by headlamps from oncoming cars or streetlights at rural intersections. But it was bright enough that I could see my surroundings without feeling afraid. Perhaps if an animal had jumped in front of my bike I would have been in trouble, but I could see several metres in front of me.
What surprised me the most is that objects (including me!) cast distinct shadows. Intellectually, this should come as no surprise -- that is how physics works. Experientially, it blew my mind that the moonlight was bright enough that I cast a clear shadow as I was cycling. I am pretty certain I have heard the term "moonshadow" before, but I had never thought about what that term meant.
Tonight the moon was full and thus at its brightest. Now I am wondering how much of the moon needs to be lit in order to see at night.
Although I have not (yet?) blogged about it, I missed the totality of the April 8 solar eclipse because I went to work. Having experienced the 99% eclipse, I feel regret that I did not take time off to watch the total one. That feels like a once in a lifetime event I missed. In contrast, there is a full moon every month, and several months of the year are clear enough that one might experience its light. And yet I have never done so, and I certainly did not intend to do so today. Artificial lighting and city living has many many advantages, but losing the night sky and the rhythms of the moon has been a nontrivial price to pay. Our ancestors were in touch with the moon in a way that we are not, even though intellectually we know much more about moon facts.
There is one moon fact that struck me especially deeply as I was cycling; the sun, not the moon, deserved the credit. What I think of as moonlight is actually sunlight that reflects off the moon and then down to Earth, and it is still bright enough that I can see. The sun is a powerful entity.