For many people, this time of year brings joy.
I'm no exception, but it hasn't been solely because of parties and presents. I've been particularly happy lately for another reason: My shadow has been getting shorter and shorter.
December 21st was the day of the winter solstice in the Northern Hemisphere. This meant that at high noon, the Sun was lower in the sky — and thus my shadow was longer on the ground — than on any other day of the year. Since that low point, the Sun has been arcing higher across the sky, lengthening each day and also shrinking my shadow.