December 10, 2013

How Much Solstice Do You Know?

Hi everyone. Since we’re getting in a winter holiday mood, we thought it would be interesting to track some of the origins of holidays at midwinter … so here we go.

c3cf29e70c74bc9d375c27d06549d1a5The winter solstice in the northern hemisphere is the time at which the sun appears at noon at its lowest altitude above the horizon. It occurs on the shortest day and longest night of the year. The significance of the midwinter event appears to have been recognized even during Neolithic and bronze age times. At Stonehenge in Britain and Newgrange in Ireland, the axes of the structures seem to have been carefully aligned to the solstice sunrise (Newgrange) and sunset (Stonehenge). The solstice would have been very significant to people not certain of living through a harsh winter, called the “famine months.” In temperate climates, the midwinter festival was the last feast celebration before deep winter began. Most cattle were slaughtered so they would not have to be fed during the winter, so it was almost the only time of year when a supply of fresh meat was available. The majority of wine and beer made during the year was finally fermented and ready for drinking at this time – a cause for celebration in uncertain times.

winter-solstice-fairbanks-alaskaKnowledge of when the solstice occurs has only recently been determined to near its instant according to precise astronomical data tracking. It is not possible to detect the actual instant of the solstice. To be precise to a single day, one must be able to observe a change in azimuth, or elevation less than or equal to about 1/60 of the angular diameter of the sun. Observing that it occurred within a two-day period is easier, requiring an observation precision of only about 1/16 of the angular diameter of the sun. Thus, many observations are of the day of the solstice rather than the instant. This is often done by watching the sunrise and sunset using an astronomically aligned instrument that allows a ray of light to cast on a certain point around that time.

There are many, many celebrations that occur at or around the winter solstice. Most familiar of these are Christmas which is celebrated by the Christian world, Hanukkah, the Jewish Festival of Lights, Hogmanay in Scotland, Junkanoo in the Bahamas and Jamaica, Yule celebrated by the Germanic peoples, Dongzhi Festival practiced in some East Asian cultures, and many more.

No matter how you celebrate midwinter, we hope the time is full of love, laughter, and light.