December 21: Warming everyone up for the merrier spirit of December and Christmas, Google’s snowy doodle is marking the shortest day of the year on December 21 with the Winter Solstice. The winter solstice falls every year around December 21, the moment at which Earth’s axis tilts the Northern Hemisphere farthest from the sun’s warmth. It is the year's shortest day, but the start of winter also launches the sun's steady climb toward the long, warm days of summer. The day is also known as the first day of winter in the Northern Hemisphere.
The winter solstice is also known as midwinter which is the shortest day and the longest night of the year. This astronomical event will officially arrive when the sun is directly over the Tropic of Capricorn, or 23.5° south latitude which will be on Friday at 5:23 p.m. EST.
About Winter Solstice:
The term solstice comes from the Latin word 'solstitium' which means 'Sun standing still'. The Sun appears to stand still at the Tropic of Capricorn and then changes direction as it reaches the most southern point as seen from Earth.
On Winter Solstice, the polar North receives no energy from the Sun. In contrast to the amount of incoming solar energy the Earth receives on June 21 which is Summer Solstice, is 30 percent higher at the North Pole than at the Equator. At this time of year, because Earth is nearing its closest point to the sun in its elliptical orbit, each day is about 24 hours, 30 seconds long.
Even though December 21 is the shortest day of the year for the Northern Hemisphere, it does not mean every location has its earliest sunset or latest sunrise on the same day. Also, it is true that the Northern Hemisphere will get the least direct sunlight on the winter solstice, but it will not necessarily be the coldest day of the year. The coldest months are yet to come, usually in January or February, depending on the region.
To consider the historical significance of this solstice, the stones of Stonehenge, England have silently marked the winter solstice where Pagans have celebrated it for thousands of years. Every year on this day, people gather to pay homage to the winter solstice at Stonehenge. It is an annual event, where those celebrating go to watch the sunrise on the shortest day. Although no one knows for sure why Stonehenge was built some 5,000 years ago, some historians suggest that it was used to mark solstices and equinoxes, because the structure is directly aligned toward the sunset during the winter solstice. Winter solstice is significant at Stonehenge because it was when cattle were killed so they wouldn't have to be fed in winter and wine and beer was fermented too, according to historians.
There are some other monuments significant to the Winter Solstice like New Grange, in County Meath, Ireland, which points to the winter solstice sunrise and Maeshowe, Mainland, Orkney, Scotland, which also faces the winter solstice sunrise.