Monday, December 22, 2014

Hooray for the analemma!

The winter solstice is today.  Today is the day that officially begins the winter season but more optimistically, today is the day when days cease their shortening and allow nights to shorten instead.  The path that the sun makes with its directly overhead position is the "analemma".  The path is a kind of figure 8 and its usual graphic representation appears on many globes of the earth, usually out in the Pacific ocean.


The winter solstice can be a big deal if you worry that the lowering sun might sink below the horizon permanently.  Then, where would we be?  No sunlight, no plants, no food and plenty of cold and colder.  It is true that the deeper cold has yet to show up and it probably will.  But just as robins, daffodils and leaves on the trees are signs of coming warmth, the winter solstice tells us that  the process of lengthening darkness has ended and longer days with shorter nights will now begin.


All the details are worked out and they can be rather complex.  Here is the Wikipedia on the "analemma":

None of these points is exactly at one of the ends of the analemma, where the Sun is at a solstice. As seen from north-mid-temperate latitudes, as the diagram shows, the earliest sunset occurs some time before the December solstice - typically a week or two before it - and the latest sunrise happens a week or two after the solstice. Thus, the darkest evening occurs in early to mid-December, but the mornings keep getting darker until about the New Year.


To me, the main point is that things are on the upswing.  If you want to, you can start to mourn a type of downturn starting at the summer solstice, when the days begin shortening again.



--
Bill
Main blog: Fear, Fun and Filoz
Main web site: Kirbyvariety


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