31 October 2008

Hallow's Eve

Seasons are a funny thing. We celebrate the start of summer on the solstice, the longest day of the year. From that point forward, the days shrink in length--we get less and less daylight in our 24 hours. We lose daylight until the solstice in December. The pagan Celts and their Nordic brethren started their summer around the time of our May Day. They called it "Beltane." This was the point halfway from the March equinox to the summer solstice. That way they were enjoying the continously lengthening days until midsummer, the solstice. Then it was downhill until fall. These solstices and equinoxes divide the year into quarters. If the orbit of the earth around the sun is viewed as a circle with the sun in the middle, these points are ninety degrees apart, forming right angles to each other. The orbit is not a circle of course, but an ellipse. The eccentricity of the ellipse, however, is quite small, 0.0167. The earth has a perihelion (closest approach) of about 147 million km and an aphelion (furthest distance) of 152 million km. So you can see that visualizing a "circle" is a useful device even if incorrect. If we further subdivide the quarters, bisecting them, we get the traditonal "cross-quarter" days of the pagan calendar. The Roman Catholic All Saints Day (Hallowmas, or All Hallows), is celebrated on November 1st, thus explaining the origin of Hallowe'en. The cross-quarter day we are approaching is called Samhain, and celebrates the end of the harvest season and the beginning of winter. We don't reckon winter until the December solstice, and after that point, the days begin to lengthen! Here in the State of Jefferson, we've already had freezing temperatures and the autumnal "fall" of the leaves is past its peak. Maybe those Celts and Vikings were on to something. The actual cross-quarter event (as reckoned from the earth's position along the ecliptic) will occur this year on November 6. I usually don't consider it winter around here until the Ski Park opens! (Thanks to archaeoastonomy.com for inspiration and information.)

1 comment:

nancyo said...

It is a pleasure to read the writing you do and, of course, it is always a good feeling to learn something new. Thanks! I don't think I knew about 'cross-quarter' days. Happy All Hallows Eve -- I wonder if Maire (or others) says Happy Samhain, hmmm....