The cold dark days of December arrive with the winter solstice, and two meteor showers surround the date, bringing brief bursts of light.
The Winter Solstice for the Northern Hemisphere occurs at 7:22 p.m. EST on December 21, 2006. (Also stated as December 22, 00:22 UT. However, I live in North America so I use the December 21 date.) This is also known as the December Solstice, because the solstice also occurs for the Southern Hemisphere but marks their start of summer, not winter.
(See the First Day of Winter for upcoming years.)
Earth spins on its axis once a day and revolves around the sun once a year. But the spin on its axis is not straight up and down; it's at a 23 degree angle. As Earth revolves around the Sun, the North Pole points to the same spot in space - the star Polaris. So at one point in its orbit, Earth's North Pole will be tilted toward the Sun, but at the opposite point in its orbit, it will be tilted away. When the North Pole is tilted away from the Sun, it receives less hours of sunlight and less direct rays from the Sun. December 21 marks the first day of winter for the Northern Hemisphere. On that day the Sun, which has appeared to us to be moving farther south every day during sunrise and sunset, will come to a standstill. It has reached the farthest point south that it will reach before eventually returning north for the warmer seasons.
As you have already noticed before December 21, the sun began setting earlier and rising later, and darkness consumed much more of your waking hours. Many people spend their entire daylight hours inside an office building in winter. To answer a common question of "How many daylight hours are there on the winter solstice?" you have to specify what location you are talking about. For example, in West Palm Beach Florida, the sun rises at 7:05 am and sets at 5:32 pm. Farther north in Milwaukee, Wisconsin, the sun rises at 7:20 am and sets at 4:20 pm. And way up in Anchorage, Alaska, the sun rises at 10:14 am and sets at 3:41 pm. To calculate sun rise and set times for any place in the US for any day of the year, visit the Naval Observatory's web site.
There are two light shows in December to get you through these "dark days," one about a week before the solstice and one occurring with the solstice.
The first meteor shower in December is the Geminids. The meteors radiate from the constellation Gemini, which rises soon after sunset. However, it is better to wait for it to rise higher in the sky. The peak of the meteors occurs on December 13, with the moon being just past last quarter.
The second meteor shower in December is the Ursids. The meteors seem to radiate from a point near Ursa Major, just north (left) of the Big Dipper asterism portion of the constellation. The shower peaks on December 22. If you go out just after sunset you can also catch the moon on the opposite side of the sky, setting in the southwest with Venus sinking farther down as it just slides behind Earth.
