In the Northern Hemisphere, the Winter Solstice occurs on December 21, 2008 at 12:04 UT (Universal Time). That means that Winter officially begins at 04:04 on the morning of December 21, 2008 for us Pacific Time types.
For those of you visiting from one of the classroom programs I’ve done recently, this is one of two points in the Earth’s orbit at which the axis of the Earth’s daily rotation crosses the axis of the Sun (technically, the axis of the Earth’s orbit around the sun). What this means is that tomorrow, December 21st, is going to be the shortest day of the year. From here on out, the days will get longer and longer, until, six months from now, we will once again have the Summer solstice.
If you look at the graphic on the left, we are in the far right position, where the south pole crosses the south pole of the sun.
Many ancient cultures (and a few modern ones) assigned great significance to the solstices and equinoxes. The Winter solstice in particular was frequently associated with festivals. Some of these were designed to ‘bring back’ the sun, and some were merely celebrating that it would not get any darker than it was.
So, here’s to more light in the coming year! Happy Solstice!