Almost midnight. Somehow a special
hour, although it exists only on a clock. There is a midpoint
between sunset and sunrise, but it doesn't fall at a particular hour
every night. I'm sure there are tables on the internet to say when
those times are, but I'm not really interested in looking it up.
Why do we insist that moments like this
fall on our kind of schedule? The night has a moment when it is
halfway over. We choose to claim that that moment is when both hands
are pointing at the twelve on our clocks. The actual definition of
midnight is when the place you are standing on is directly opposite
that point on the earth where the sun is at its highest point in the
sky.
That means that midnight is a great
circle marching across the globe, halfway between the two terminators
(dawn and sunset). There is a point each night when this great
circle passes over you, and part of you is in the night and part in
the morning. Midnight travels at 1000 miles an hour, give or take,
depending on your altitude.
And so, if you think about it, does
every second of every day. Breaking time into zones, large areas
where every clock reads the same, is as artificial as it gets. If
time is measured relative to midnight, dawn, noon and sunset, then
every line drawn from North to South Poles is at a slightly different
time of day.
And we are the only animals that really
worry about anything like this. Seasons matter to birds, butterflies
and rabbits. Salmon need to know when to leave for the spawning
grounds, bears need to know when to start hibernating, but not an
animal out there, mayflies included, need to know whether it's 3:14pm
or not.
On the other hand, birds, bears and
mayflies don't do much in the way of major structural engineering, so
maybe there is something to the idea of keeping time the way we do.
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