Throughout the year, the time allotted to daylight each day changes. Longer times of daylight coincide with summer, which is different north and south of the equator. Summer is when the earth’s tilt favors one hemisphere or another.
Near the poles, summer daylight gets so long that at its peak there is no night; the sun just makes a circle above the horizon. Of course, in winter, that means that there are l-o-n-g nights. Even here in North America, within the lower 48 states, the difference between sunrise in Maine and sunrise in Florida on any given day can be significant. Add the difference at dusk, and you find that sunny Florida gets a shorter amount of daylight than chilly Maine.
But there are two days a year, the vernal (spring) equinox and autumnal (fall) equinox during which the amount of daylight and dark are approximately equal—approximate because you have to allow for variations due to refraction, etc. It doesn’t happen on the same date each year; the autumnal equinox, for example occurs anywhere between 21 September and 24 September.
Incidentally equinox is constructed from the Latin words for equal and night. I have to wonder why they didn’t call it equal day. Perhaps day was time for work, but the parties and other fun happened at night.
Friday, 22 September, is the autumnal equinox, when light and dark are pretty much equal. Maybe we should take some inspiration and focus on where we could be pretty much equal. For example, spending the same amount of time listening and thinking about what was said to match thinking of what we’re going to say and talking. (Don’t forget to include the time to think).
If everyone did this, it could be a celestial event of astronomic proportions.
sfnowak 