Wednesday, December 20, 2023

Let's Welcome Winter

The earth's axis of rotation is not perpendicular to the plane described by its orbit around the sun. If it were perpendicular we would have no seasons and each day and each night would equal 12 hours. Instead it tilts some 23.5 degrees from perpendicular.

Twice a year the top and bottom of the earth's axis are equidistant from the sun, and we have the equinoxes - spring and autumn. Happening in March and September, around the 21st of each month, everywhere on earth experiences 12 hours of daylight and 12 hours of darkness.

And twice a year the top and bottom of the earth's axis are either nearest to, or farthest from, the sun. Tomorrow we reach one of these two events, as they occur around the 21st of June and December. 

This one is at roughly 7:30 p.m. PST and in the northern hemisphere we call it the Winter Solstice, when winter begins. The North Pole is farthest from the sun tomorrow, we northerners will have the least daylight and the most darkness of the entire year. South of the equator they have the most daylight and least darkness, there it is the Summer Solstice, summer is beginning.

We humans have been celebrating the turning of the season for millennia, as shown by Paleolithic constructions like Stonehenge, Newgrange and the Mayan calendar. I endorse that tradition, and in my own small way, continue it. 

Postscript: The DrsC were out and about today running errands, reveling in the sunshine and short sleeves weather the desert enjoys this time of year. I took a light jacket and never had it on.