Today, while most of us are having lunch or running holiday errands, the sun will pause briefly in its journey across the sky, and shift its course slightly northward. In the Northern Hemisphere, today is the winter solstice, and it occurs at 12:11 p.m. EST. The sun’s path doesn’t actually change, but thanks to the earth’s 23° tilt, it looks that way to observant earthlings.
The solstice produces the shortest day, and the longest night of the year. Today that trend will reverse. Starting tomorrow, days will be a longer and nights shorter. With instant light at our fingertips, all this astronomical hoopla is no big deal, but for most of human history, having more daylight was cause for celebration.
I won’t be lighting bonfires or attending any raucous parties, but my celebration will be a personal, astronomical observation here at home. In addition to the shortest day, the solstice creates the longest noontime shadow of the year. In true geek fashion, I plan on measuring the length of my shadow, and making a comparison to the measurement at the summer solstice, which occurs on June 21, 2014 at 6:51 AM (ET).
Hey, it should be fun (in a nerdy sort of way)! Doesn’t everyone want to be taller and thinner? Give it a try where you live and report back.
*** Update: Report From the Field ***
With the help of my trusty lab assistant Terri, I measured my shadow at noon on the Winter Solstice. I am 6 ft 1in, and my shadow was 9 ft 4 in. I suspect that there’s some trigonometric rule that explains why my shadow is almost exactly 1.5 times my height, but my trig is a bit rusty. Also, unless I miscalculated, the angle of the sun is 33° above the horizon. My sister-in-law Ellen would say that this is a perfect example of “math for no reason,” but there you have it.