Peak Twilight

Happy Crepusculus! Tonight is the earliest sunset of the year: 4:12:02 PM. At least it is for me and everybody else at my latitude. This image, taken last week, shows the exact moment of every sunset for the week preceding and following today’s early sunset.


Almost every sunset falls between 4:12 and 4:13. It’s like the sun is standing still! We should give this season a special name to honor this remarkable observation. We’ll call it Sun-Still. No, how about Sun-No-Go? No. How about something fancy and Latin sounding, something derived from sun (sol) and standing still (sistere): solsistere. Sol-sister? Okay fine, let’s just shorten that to solstice. I’m sure everyone will figure out what it means.

If you already know about the solstice but are surprised that it’s happening as early as December 8th, I should point out that this is merely the earliest sunset. The latest sunrise is in January, leaving the shortest day on December 21st where it belongs. If it seems surprising that the earliest sunset and the latest sunrise don’t coincide, you can blame the earth’s slightly elliptical orbit around the sun.

In the meantime, I’m more than happy to celebrate the slow retreat of sunset. Today may not be the actual solstice, but it’s worth observing for its own merits, so I’ve given it the name Crepusculus (more Latin: twilight = crepusculum).

Happy Crepusculus!