Passover 2011: What is Passover?

Passover 2011: What is Passover?
Passover begins on the 15th day of the month of Nisan, which typically falls in March or April of the Gregorian calendar. In accordance with the Hebrew Bible, Nisan is the first month of the Hebrew calendar's festival year. Passover is a spring festival, so the 14th day of Nisan begins on the night of a full moon after the vernal equinox. To ensure that Passover did not start before spring, the tradition in ancient Israel held that the first day of Nisan would not start until the barley is ripe, being the test for the onset of spring. If the barley was not ripe, or various other phenomena indicated that spring was not yet imminent, an intercalary month (Adar II) would be added. However, since at least the 4th century, the date has been fixed mathematically.

In Israel, Passover is the seven-day holiday of the Feast of Unleavened Bread, with the first and last days observed as legal holidays and as holy days involving abstention from work, special prayer services, and holiday meals; the intervening days are known as Chol HaMoed ("Weekdays of the Festival"). Diaspora Jews historically observed the festival for eight days, and most still do. Reform and Reconstructionist Jews and Israeli Jews, wherever they are, usually observe the holiday over seven days. The reason for this extra day is due to enactment of the Sages. It is thought by many scholars that Jews outside of Israel could not be certain if their local calendars fully conformed to practice of the Temple at Jerusalem, so they added an extra day. But as this practice only attaches to certain (major) holy days, others posit the extra day may have been added to accommodate people who had to travel long distances to participate in communal worship and ritual practices; or the practice may have evolved as a compromise between conflicting interpretations of Jewish Law regarding the calendar; or it may have evolved as a safety measure in areas where Jews were commonly in danger, so that their enemies would not be certain on which day to attack.