In the Sky: The ‘Star Geezer’
December 29, 2008
Besides the colder temperatures, the great snow conditions and the increased frenzy of socializing that marks the holiday season, certainly the most noticeable feature of this time of year are the short days or, conversely, the long nights. It’s that last one ” the nights ” that this debut edition of “In the Sky” will address. I’m the Star Geezer.
The first thing to realize about most celestial events is that while much of what we see in the sky can be predicted, that doesn’t necessarily mean those events conform to an easy set of rules. For instance, the dates of the earliest sunset, latest sunrise and even the solstices and equinoxes are quite fluid when it comes to easy predictions. Perhaps stranger, however, is the fact that neither the earliest sunset nor the latest sunrise occur, as one might logically assume, on the winter solstice. Still with me? I’ll try to explain.
In 2008, according to my celestial bible, “The Old Farmer’s Almanac,” the earliest sunset occurred at the officially listed time of 4:12 p.m. (the actual time may be different where you live, but it’s the relativity we’re interested in here) on Dec. 8, a full two weeks before the solstice, or what we commonly call the shortest day of the year. Keeping in mind that the official sunset was 4:12 p.m. for 13 days, the daily changes were minimal but by the time we got to the actual solstice on Dec. 21, sunset occurred at 4:15 p.m. And by the time we get to the latest sunrise on Dec. 31 (at 7:14 a.m.), sunset will be at 4:22 p.m. and the sun will be setting close to a minute later every day.
Why does this all happen? Well, the complete answer lies in a grandiose term called “The Equation of Time.” To oversimplify, what many astronomers refer to as a “wobble” in Earth’s elliptical orbit around the sun ” we go faster or slower depending on our position in that orbit ” combined with other effects arising from the Earth’s 23-degree tilt on its axis create the apparent discrepancy. So while the longest night does occur on the solstice, the earliest night “the marker that really matters more psychologically ” happened thee weeks ago.
Also, watch for one of the best meteor showers of the year the night of Jan. 3-4, the Quadrantid Meteor Shower. Look to the north in the predawn sky and with clear weather you should see a “shooting star” about every two minutes.
Next time: eclipses for 2009.