The sun hit its southernmost setting point, ending the shortest day of the year, this evening at 4:50, as a couple of dozen aficionados observed from the Cesar Chavez Memorial Solar Calendar atop a west side hilltop in the park. Lawrence Hall of Science staffer Alan Gould gave a brief explanation of the dynamics and mechanics involved in the solstice. Solar Calendar creator and curator Santiago Casal was present. Also present was Rabbi David Cooper, who has led other solar calendar celebrations at this site. The weather was most cooperative, with temperatures cool but not chilly, the absence of wind, and just enough clouds in the western sky to dress up the sunset.
Here’s a pretty thorough scientific explanation of the solstice in the Washington Post.