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Seasons without Borders: December 2011 Solstice

Image credit: Tunc Tezel/TWAN. " Four Seasons of Lake Venus " It is that time in our orbit around the Sun when we are closest to our parent star—a result of the slight eccentricity in Earth’s orbit.  But despite being closer to the Sun’s heat, those living north of the equator are having the coldest weather of the year.  In the Southern Hemisphere the situation is reversed, with the year’s warmest weather.  These seasonal changes are caused by the 23½ degree tilt of the Earth, relative to the plane of its orbit around the Sun. It is time for the December Solstice—the Winter Solstice in the north, the Summer Solstice in the south—which will happen at 05:30 UT on 22 December 2011.  At this moment our Sun reaches its southernmost declination of -23.5 degrees—which is the angle of the North Pole’s tilt.  The Northern Hemisphere experiences its shortest day while the Southern Hemisphere celebrates its longest day of the year.  All places above 66.5 degrees north latitude will be in 24 hours of darkness, while locations below 66.5 degrees south will receive 24 hours of sunlight. This date is also called the first day of Winter in the north and the first day of Summer in the south.  The name “solstice” comes from the Latin words “sol,” meaning “sun,” and “sistere,” meaning “to cause to stand still.”  Thus, on the December Solstice the sun appears to stand still in its day-by-day progress southward. Solstices can occur any time from the 20th through the 23rd of... Read More..