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What Do You Mean, "Year"?
Aug. 10th, 2014 04:51 pmA few days back I quoted a passage from Alexei Panshin's Star Well:
The first date given follows the old Roman calendar, dating from the traditional year of the founding of Rome. The second, of course, dates from the traditional year of the birth of Jesus. The fourth appears to be based from the launch of Sputnik 1. Translation among these three eras is a simple matter of addition and subtraction, but the remaining era is not so simply related. The Muslim calendar dates from the year A.D. 622, but the Muslim year, being purely lunar and making no concession to the solar year, is only 354 or 355 days long; hence, the Muslim calendar gives the year as (approximately) (Common Era - 622) * 1.03. The year A.D. 3418 will be the year A.H. 2882 (+/-1, since the years overlap), not 2795.
(In my History of Math class, early on, I allocate roughly one lecture to calendars and calendar reform, and challenge my students to determine when the Gregorian and Muslim calendars will at last, if briefly, agree.)
To history buffs, the year was 4171 A.U.C. To Christians, it was 3418. To Moslems, it was late in the year 2795. But by common reckoning, the year was 1461.I objected to one of the four numbers there given, and promised an explanation later. Here it is.
The first date given follows the old Roman calendar, dating from the traditional year of the founding of Rome. The second, of course, dates from the traditional year of the birth of Jesus. The fourth appears to be based from the launch of Sputnik 1. Translation among these three eras is a simple matter of addition and subtraction, but the remaining era is not so simply related. The Muslim calendar dates from the year A.D. 622, but the Muslim year, being purely lunar and making no concession to the solar year, is only 354 or 355 days long; hence, the Muslim calendar gives the year as (approximately) (Common Era - 622) * 1.03. The year A.D. 3418 will be the year A.H. 2882 (+/-1, since the years overlap), not 2795.
(In my History of Math class, early on, I allocate roughly one lecture to calendars and calendar reform, and challenge my students to determine when the Gregorian and Muslim calendars will at last, if briefly, agree.)
