SCIENCE OF THE SOLSTICE
As we’ve mentioned before, the Romans celebrated a holiday known as the Saturnalia beginning on the Winter Solstice. The word Solstice comes from the Latin “solstitium” meaning “Sun, standing-still.” This year it will occur on December 22 at 00:22 UT (Greenwich Universal Time.)
Earth enjoys different seasons because the planet is tilted 23 degrees and 27 minutes off the perpendicular to the plane of orbit. This means that the earth revolves like a tilted spinning top. The Winter Solstice is the shortest day of sunlight as the Sun is at its lowest arc in the sky, at least in the Northern Hemisphere. The farther north one is from the Equator, the more pronounced this is in Winter. However, as the Earth continues its orbit, the hemisphere that is angled closest to the sun changes, and the seasons are reversed.
In the Northern Hemisphere the sun appears at its lowest point in the sky, and its noontime elevation appears to be the same for several days before and after the solstice, so that it looks like the Sun is “standing still” until following the winter solstice, the days begin to grow longer and the nights shorter.
Bill Petro, your friendly neighborhood historian