I began studying Fortran, a computer language in the first semester of graduate school. We had a computer department on the campus and people to staff it. As far as I could tell, the people in the department were developing their curriculum and department as they went along. This was the mid 60's. Our teacher was openly developing his knowledge of Fortran and computer use at the same time we were. There were six of us in the one-credit class. The teacher gave us one assignment but it ran for three years. In the end, I finally got the one credit I have in computer science.
That one assignment was to write a computer program which would take any two dates as input and give the number of days between them as output. At first, that seemed straightforward and easy. But our teacher was very tricky. He was also inventing twists, turns and extensions as time went on. Researching possible challenges he might give us, we learned that in1752, all British lands, including the American colonies, agree to accept the calendar adjustments created much earlier under Pope Gregory XIII to correct the calendar. The Pope's astronomers had calculated that the calendar needed to omit 11 days for better adjustment and different countries adopted the correction at different times. The British lands had riots over the correction, where some workers feared the shortened month would result in less pay. It seems that the calendar riots resulted in full pay for that month's work.
We just recently had the winter solstice here on earth, the moment when the earth's north pole is tipped as far away from the sun as it ever gets (we hope!). I carry in my head the dates of the 21st of December, March, June and September for the change of the seasons but I have seen that the calendar sometimes says the 22nd of the month is the pivotal change for a given year. I have read that the exact moment of the solstice can happen on any day from the 20th to the 24th. This year, according to various web sites, the winter solstice occurred at 10:49 PM Central Standard Time. After that time, for about 6 months, we will get longer days and shorter nights. The longer days, with more sunshine, will give us spring and blooming plants. We still have many days to go before the winter days are noticeably longer and brighter but we are on our way.
Since we cussed and re-punched our computer cards to try to meet the tests of our teacher for three years, I have great respect for the scholars, calculators, thinkers, and debaters in many lands for many governments and organizations over several millennia to try and find a humanly useable system that combines in a fairly simple and straightforward way, the days, the weeks, the months and the seasons. Three cheers for the calendars!
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