Date: 03/28/2002 at 07:38:42 From: Ellie Spitz Subject: Jewish calendar If the Jewish calendar has the same number of days each year, why do the Holidays fall at a different time each year? Thank you.
Date: 03/28/2002 at 08:35:40 From: Doctor Rick Subject: Re: Jewish calendar Hi, Ellie. The Jewish calendar is both a lunar and a solar calendar. The months are lunar months: they all start at the new moon, which makes them about 29 days long. But twelve 29-day months would be only 348 days, making a 12-month year seventeen days short of a solar year. The Muslim calendar lets this discrepancy stand: it is a strictly lunar calendar, so the year is about seventeen days short, and the holidays rotate rather rapidly around the seasons. (The month of Ramadan can occur at any time of year.) The Jewish calendar doesn't have this problem because an adjustment is made. In certain years a 13th month is inserted to bring the months back into alignment with the solar year. Thus the holidays do not rotate around the seasons: Passover always falls shortly after the spring equinox. The variation that you see in the dates of Jewish holidays is due only to the fact that the months don't start on the same days as in the Western (Christian) calendar. As I said, each Jewish month begins at the new moon. But in the Western calendar, a month can start on any day of the lunar cycle. It is worth noting that the timing of the Christian holiday of Easter acknowledges its close association with Jewish holidays. Christ was crucified in the season of Passover, and Passover starts on the 15th day (full moon) of Nisan, the first month of spring. Therefore Easter falls on the Sunday after the first full moon after the spring equinox. (That's a loose description that isn't entirely accurate.) Most of the time, therefore, Passover and Easter fall at about the same time; but occasionally they get out of sync by a month because of differences in the details. Here is one interesting Web site on the Jewish calendar; the same site has a page on the date of Easter. I can't vouch for its accuracy because I am not an expert in this field. Historical Ecclesiastical Calendar: The Jewish Calendar - Karl T. Hagen http://ourworld.compuserve.com/homepages/khagen/Jewish.html - Doctor Rick, The Math Forum http://mathforum.org/dr.math/
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