At this time of year, we are all thinking of our various winter festivals. Christmas, Hanukkah and most other winter holidays have a common origin in the celebration of the winter solstice – people gathering at the shortest day of the year to bring light to the darkness.
Astronomically, the solstice is a relatively simple phenomenon. The earth’s axis is tilted by 23.5 degrees relative to the earth’s orbit around the sun. As the earth orbits the sun once per year, different parts of the earth receive the greatest part of the sun’s energy (and the longest days), due to the tilt. In December, the Southern Hemisphere is tilted towards the sun and receives the greatest part of the sun’s energy, while in June, the opposite is true and the Northern Hemisphere basks in the light. December 21-22 is when this effect is at its maximum, so the Northern Hemisphere has its shortest day (and longest night) of the year.
Here at GMD in Vermont, our shortest day is just less than 9 hours of daylight (and conversely, a night over 15 hours long). If you live south of us, your day will be somewhat longer, so that people living in Washington DC or San Francisco will see a day that is close to 10 hours even on the winter solstice, and if you live in Miami, the day never gets shorter than 10 ½ hours. Conversely, if you live north of us, the shortest day is even shorter – the residents of London only see an 8 hour day on the winter solstice.. If you live in the tropics, day length hardly varies at all through the year – Costa Rica sees an 11 ½ hour day today.
Most cultures who live in places with widely varying day length have a festival to celebrate passing the shortest day and the gradual return of the sun. These traditions go back thousands of years – Stonehenge is aligned to the position of the sunset on the winter solstice, and this stage of its construction occurred approximately 4600 years ago. While we have no knowledge of the traditions and festivals of the people who built Stonehenge, many of the celebrations we do have a record of are focused on a struggle between light and darkness, which, in the darkest time, light finally begins to win again. Traditions often focused on evergreens, fire and community coming together. If this sounds a lot like Christmas, there is no coincidence there – Christmas is an evolution of earlier solstice festivals, and its celebration borrowed many elements. The date of Christmas was not fixed until the 4th century, and is believed to have been chosen to correspond with the shortest day.
In addition to cultural celebrations of the first stirrings of a return of light, there are a few natural moments of rebirth that occur at this time of the year. One of my favorites in New England is that the breeding season of the Great Horned Owl is about to begin. We will soon hear their haunting low hoots as they call out to each other and find their mates. As winter continues, more and more things will begin to stir, even though we are still three months or more from the re-emergence of the first hardy plants. By the end of January, the days will be noticeably longer than they are now, and I always feel rejuvenated by the coming of the light, even though the days are still cold.
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