Today marks the first day of winter in the northern hemisphere. It’s the shortest day of the year for the Los Angeles area; the solar disk will be above the horizon for only 9 hours and 54 minutes today at our latitude.
The diagram above illustrates the orbit of the Earth around the Sun and highlights the passage of our planet through eight significant portals recognized by cultures for many millennia. Those are the two equinoxes, the four cross quarter days and the two solstices. Today, we pass through the winter solstice for the northern hemisphere.
For more information about the science and lore of these several special days, check out the website Archaeoastronomy.com and have a look around.