Sun in the Winter Sky
How does science enter everyday thoughts?
The other morning walking up the street to Mad City Coffee, the sun barely crept over the top of the bare trees behind the houses. It was nearing noon and nearing the Winter solstice. I wondered how high (or low) did the sun go up from the horizon in my area, midway Baltimore-DC.
I knew it was about 40 degrees latitude and the angle of declination of the Earth’s orbit was 23 1/2 degrees. At high noon at the equator, when the declination was 0 degrees, the sun would be 90 degrees overhead.
Then, locally at noon winter solstice, the elevation should be about (90 â€“ 40 â€“ 23.5), which equals 27.5 degrees. Pretty low, a bit below that of the 30 degree angle in a 30-60-90 triangle. That seemed about right as the sun peaked just above the trees beyond.
When I got the time, I searched and found this NOAA solar elevation calculator. Hah! I was pretty close.
Math and science came together in my morning walk.