Winter Solstice Lantern Festival, Vancouver BC (photo: ItzaFineDay via Flickr)

Astronomy has always played an important role in our lives… navigation, eclipses, new & full moons, interpretation of the constellations, predicting the tides. When I was in high school, back in the very late 1960s, we actually had a planetarium at school. I took astronomy and loved it. We had to do the math to figure out orbits and such… it was pretty fascinating. I mostly don’t remember much of that math now, but it was fun at the time.

This week we celebrate the Winter Solstice. According to….

The winter solstice occurs exactly when the Earth’s axial tilt is farthest away from the sun at its maximum of 23° 26′. Though the winter solstice lasts only a moment in time, the term is also a turning point to midwinter or the first day of winter to refer to the day on which it occurs. More evident to those in high latitudes, this occurs on the shortest day, and longest night, and the sun’s daily maximum position in the sky is the lowest. The seasonal significance of the winter solstice is in the reversal of the gradual lengthening of nights and shortening of days. Depending on the shift of the calendar, the winter solstice occurs on December 21 or 22 each year in the Northern Hemisphere, and June 20 or 21 in the Southern Hemisphere. The 2010 winter solstice will occur on December 21, at 23:38 pm UTC.

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And further on, also from wikipedia…

The solstice itself may have been a special moment of the annual cycle of the year even during neolithic times. Astronomical events, which during ancient times controlled the mating of animals, sowing of crops and metering of winter reserves between harvests, show how various cultural mythologies and traditions have arisen. This is attested by physical remains in the layouts of late Neolithic and Bronze Age archaeological sites such as Stonehenge in Britain and Newgrange in Ireland. The primary axes of both of these monuments seem to have been carefully aligned on a sight-line pointing to the winter solstice sunrise (New Grange) and the winter solstice sunset (Stonehenge). Significant in respect of Stonehenge is the fact that the Great Trilithon was erected outwards from the centre of the monument, i.e., its smooth flat face was turned towards the midwinter Sun. The winter solstice may have been immensely important because communities were not certain of living through the winter, and had to be prepared during the previous nine months. Starvation was common in winter between January and April, also known as 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. The concentration of the observances were not always on the day commencing at midnight or at dawn, but the beginning of the pre-Romanized day, which falls on the previous eve.

Wendy Davis has written a post about the full moon that is part of this winter solstice… such a thing has not happened for centuries. And Ruth Calvo has written a post about Newgrange.

Edited: Hey! I can still edit, so I’m adding twolf’s post to the post, rather than just having it in the comments.

Please feel free to consider this as an open thread…if there is anything else you would like to discuss.