Monday, June 21, 2010

Longest Day and Shortest Night

This year I greet the longest day well-prepared and without frustration thanks to a splendid illustration I managed to find on the website of the Yohkoh Outreach Project, an organization jointly sponsored by Montana State University and Lockheed Martin Solar and Astrophysics Lab. The site of the source is here. My frustrations arise (as earlier noted here) because my viscera really believe that the earth stands still and the sun moves. With this temperament, the usual explanation of an earth tilted on its axis tracing an elliptical path around a sun—and thus producing the seasons and the longs and shorts of days and nights—causes me bewilderment, vexation, and a sort of dizziness. I look at all the diagrams and can’t make heads or tails of them, because I’m looking at it all as from a spaceship, but actually I’m down here on the surface of the globe, right by the shores of Lake St. Claire. Yohko Outreach Project to the rescue. They’ve produced this simple, straightforward chart.



They’ve even put me in the center of it—see? And this chart, which shows the position of the sun as I would see it, from my own backyard, makes the solstices and the equinoxes crystal clear. The sun never dips lower to the south than at the Winter Solstice. After that day it rises daily to a slightly higher point in the sky. Thus the sun seems to be in motion, not only side to side, as from dawn to dusk, but also from the Winter Solstice up to the Summer Solstice. And it never goes higher than it does today. Tomorrow it reverses its course.

The name of this day, solstice, comes from the Latin for sun, sol, and sistere, to stand still. Its upward movement stands still today and reverses direction tomorrow. And it shall stand still again on December 21 and begin to rise again. Exactly in the middle of that process we have the equinoxes, coming and going. At the Winter Solstice we have the longest night, today the shortest, and in the middle night and day have the same length: equi nox.

Deep sigh of relief. Thank you Yohkoh Outreach Project. If only more of humanity would follow your example and do good things for the needy and the ignorant. It would be a better world. Now there must be at least a dozen people like me out there who’ll get something out of this post. So enroll me, too, on the side of the angels.

1 comment:

  1. I'm totally baffled by this diagram! I for whom the spaceship model is crystal clear can not understand why your backyard is suddenly on the shores of Lake St Clair which is in the center of the Earth???

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