The long days of summer are fading, and early hints of fall are starting to creep in. The impending seasonal shift is already noticeable, not in the leaves just yet, but in the light. The summer solstice is the longest day of the year, and for North America, it took place at 10:42 p.m. EDT on June 20. Ever since then, days have been getting shorter and shorter. At first, it was just by a few seconds every day, but that change is accelerating. By August, each day is 1 to 2 minutes shorter than