Winter Solstice Poster

Features an image of the mid-winter taiga (boreal forest). Cold and covered in snow. Low on the horizon a pale, yellow sun hovers just above the mountains. A snowshoe hare runs for cover in the foreground. A solstice is either of the two times a year when the Sun is at its greatest distance from the celestial equator, the great circle on the celestial sphere that is on the same plane as the earth's equator. In the Northern Hemisphere, the winter solstice occurs either December 21 or 22, when the sun shines directly over the tropic of Capricorn The reason for the different seasons at opposite times of the year in the two hemispheres is that while the earth rotates about the sun, it also spins on its axis, which is tilted some 23.5 degrees towards the plane of its rotation. Because of this tilt, the Northern Hemisphere receives less direct sunlight (creating winter) while the Southern Hemisphere receives more direct sunlight (creating summer). As the Earth continues its orbit the hemisphere that is angled closest to the sun changes and the seasons are reversed. The winter solstice marks the shortest day and the longest night of the year. The sun appears at its lowest point in the sky, and its noontime elevation appears to be the same for several days before and after the solstice. Hence the origin of the word solstice, which comes from Latin solstitium, from sol, "sun" and -stitium, "a stoppage." Following the winter solstice, the days begin to grow longer and the nights shorter. 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, when 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. Worldwide, interpretation of the event has varied from culture to culture, but most cultures have held a recognition of rebirth, involving holidays. festivals, gatherings, rituals or other celebrations around that time. 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 (Newgrange) 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-Romanised day, which falls on the previous eve. Since the event is seen as the reversal of the Sun's ebbing presence in the sky, concepts of the birth or rebirth of sun gods have been common and, in cultures using winter solstitially based cyclic calendars, the year as reborn has been celebrated with regard to life-death-rebirth deities or new beginnings such as Hogmanay's redding, a New Year cleaning tradition. In mythology, the gods and goddesses met on the winter and summer solstice, and Hades is permitted to enter Mount Olympus {his domain is the underworld so he of course does not get accepted any other time}. Also reversal is another usual theme as in Saturnalia's slave and master reversals. Direct observation of the solstice by amateurs is difficult because the sun moves too slowly at either solstice to determine its specific day, let alone its instant. Knowledge of when the event occurs has only recently been facilitated to near its instant according to precise astronomical data tracking. It is not possible to detect the actual instant of the solstice (by definition, one can not observe that an object has stopped moving until one makes a second observation in time showing that it has not moved further from the preceding spot, or that it has moved in the opposite direction). Further, 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 1/60th 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 1/16th 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 or vice versa or using an astronomically aligned instrument that allows a ray of light to cast on a certain point around that time.