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FOUR SEASONS BREEZE | DECEMBER 2020 15 By Steve Benoff Dec. 21, 2020, will be the shortest day of the year. Sunsets are early in the evening and the sunrises late in the morning. But curiously, Dec. 21 marks neither the earliest sunset or the latest sunrise. The same will be true in reverse on June 20 for the summer solstice. The winter solstice for the northern hemisphere is the time at which the north pole is tilted farthest from the sun. (Conversely, the summer solstice for the northern hemisphere is when the north pole is tilted closest to the sun. See figure above.) For the solstices, the times of sunset and sunrise vary with a particular site's east-west and north-south location. If you concentrate on the time of sunset from day to day, you can appreciate the change. This is especially true in the months before and after the equinox of spring and fall. The change in sunset (and sunrise, too) is two minutes a day at that time. Take a look at the position of the sun at sunset in late December and compare it to its position in late June. The shift from north to south is dramatic. Drive west on Crooked Creek late in the afternoon throughout the year and you'll see for yourself. Or pick a light pole and watch how its shadow moves at sunrise throughout the year. If you hadn't noticed it before, you'll likely be amazed at how its position changes. The shift in the position of the sun from the summer solstice to the winter solstice is over 45 degrees (one-eighth of a circle). You can see it on the horizon. This year in Beaumont the earliest sunset was at 4:40 pm on Nov. 27, and though it will change by seconds each day, the 4:40 pm sunset will remain until Dec. 13 when it will shift to 4:41 pm. By the solstice it will be 4:43 pm, and it will be getting later at a rate of about a minute every two days. By early January, sunsets will be getting later by a minute a day. The latest sunrise will be on Dec. 31 at 6:54 am when it will be four minutes later than on the solstice. And the sun won't rise earlier until Jan. 15, 2021. In the summer, the earliest sunrise comes at 5:37 am on June 7 and stays at that time until June 19 when it starts getting later. Sunset, on the other hand, doesn't reach its latest time, 8:04 pm, until June 27, a week after the solstice. And it stays there until July 2. The sunrise/sunset variation from the solstice is attributable to a number of factors – the latitude of a specific location, the elliptical orbit of the earth, the tilt of the earth, the fact that a day isn't exactly 24 hours long - all of which contribute to the sunrise/sunset times. And this has to do with the fact that the solar "noon" (when the sun reaches its apex in the sky) and your clock's "noon" are not exactly the same. Currently, around the solstices, the solar noon occurs a few minutes later each day relative to the clock noon. And these factors combine to form a pattern which moves on a 21,000-year cycle. Eight hundred years ago the earliest sunset/latest sunrise coincided with the winter solstice. Don't hold your breath. It won't happen again for almost 10,000 years. The important thing is to appreciate the many factors that combine to cause the changes throughout the year of the position of the earth relative to the sun and changes in the length of sunshine. This is best observed in the changes in sunrise and sunset and the changing shadows created by the sun throughout the year. (https://en.es-static.us/upl/2012/12/seasons_solstice_equinox_ NASA.jpeg) The Winter Solstice

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