The earth has spent more time orbiting the sun than all the religions, all superstitions, all of humanity, and even of all life itself. The Winter Solstice represents an actual astronomical event unlike superstition driven celebrations that occur only in religious imagination. The exact day of the winter solstice marks the end of autumn, just one point along the orbital path of earth. The energy of the sun and the fertile earth, along with the over 4.5 billion winter solstices that have occurred, allowed enough time for all of earth's evolution to happen (and to continue to happen). This puts the Winter Solstice in a far more humbling position than anything invented by humans. Considering that the earth also comes closest* to the sun during the winter, what better time to honor the sun than during the Winter Solstice.
The festivals of the Winter Solstice celebrate the start of the new solar year and the beginning of winter. The fantasies of superstition have also used this astronomical event to celebrate Saturnalia, Yule, Christmas, and many other superstitious events. The unknown builders of Stonehenge (see photo above) in southern England constructed the megaliths at around 2000 B.C.E. which makes it at least twice as old as Christianity. It accurately predicts both the summer and winter solstices.
In astronomy, a solstice occurs two times a year. During the Winter Solstice the sun appears at its greatest distance from the celestial equator, the great circle on the celestial sphere that occurs 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 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 the same for several days before and after the solstice. The summer solstice occurs either June 21 or 22, when the sun shines directly over the tropic of Cancer. In the southern hemisphere, the winter and summer solstices appear reversed.
* It may seem contradictory that the earth comes closest to the sun during the winter and the farthest during the summer, but the seasons occur mostly because of the tilt away or toward the sun, rather than the distance from the sun.)
Stonehenge photo from rebootd.blogspot.com. The photo shows the sun setting during the shortest day of the year, between the two largest megaliths, the mark of the Winter Solstice.
For more information on the solstice:
Winter solstice and Christmas: http://home.ccil.org/~kmiles/dln/12-95/decsol.html
The Surest Sign of Winter: http://www.bisque.com/thesky/brian/20001127.htm
The Sun and the Seasons: http://www.museum.vic.gov.au/planetarium/constetour/fss/fss5.html
How the Christians stole the Winter-Solstice holiday: http://www.nobeliefs.com/facts.htm#anchor189702