Why Easter 2008 Will Arrive So Much Earlier than Usual

Easter is one of those holidays that seems to have no rhyme or reason as to calendar dates. I know for myself, I always have to check the calendar in order to find the date. But this year, I was astonished at how unusually early Easter came.

Unlike most holidays in our modern calendar, Easter is not figured by a fixed date, such as Christmas, which always falls on December 25^th. Nor is it figured by virtual dates such as Thanksgiving falling on the fourth Thursday of November. Easter is figured by the season of year and phase of the moon. This was to better follow the ancient Hebrew calendar which put Jesus' Resurrection at this time of year in 30 A.D.

According to the Astronomical Society of South Australia (ASSA), Easter Sunday is the first Sunday following the Paschal Full Moon.¹ The Paschal Full Moon is "the 14th day of a lunar month occurring on or next after March 21 according to a fixed set of ecclesiastical calendar rules and without regard to the real moon," according to Merriam-Webster's Dictionary.² The Ecclesiastical calendar, or the Ecclesiastical Full Moon dating method (EFM), was implemented by astronomers in 325 A.D. The reason Webster's Dictionary refers to it as "without regard to the real moon" was that the astronomers attempted to estimate the astronomical full moon dates for the Christian church.³ The Paschal Full Moon dating method or PFM, was used in conjunction with the Julian calendar which was unreliable after years of use. The Julian calendar is approximately 365.25 days long each year which is slightly too long.⁴ Eventually, Easter began to fall later and later and was no longer in the same season or moon phase of Christ's Resurrection.

Later, in 1583 A.D., Pope Gregory XIII devised a more accurate method of figuring Easter dates. Based on the slightly shorter Gregorian calendar, it is deduced as the PFM being the first full moon after the vernal equinox or the first full moon in the northern hemisphere.The PFM in this case was determined using a March 20^th date rather than the old Ecclesiastical idea of the March 21^st date.⁵ It was more accurate for the moon phase. Thanks to the Gregorian calendar, which removed about 10 days from the Julian calendar, Easter once again fell in the correct season. ⁶

Some Orthodox churches still use the PFM and Julian calendar system. Once in awhile their Easter matches up with the western calendar such as in 1990. But generally, Orthodox Easter is celebrated up to two weeks later than the western Easter.⁷

So the earliest Easter can ever fall is March 22, which would have to be a Sunday following the PFM on March 21. The latest it could fall is April 25^th. This year, 2008, Easter does fall unusually early and it has not been this early since 1913. This is the last time we will see Easter fall this early in most of our lifetimes. In fact, the next time Easter falls on March 23, the year will be 2160.⁸

As for the earliest date possible, March 22, we will not see this in our lifetime at all. The last time it happened was 1818 and the next time will be 2285. It is far more likely to see later Easter dates than early. The last time Easter fell on April 25^th, the latest possible date, was 1943 and we will see it again on 2038.⁹

For further information on how to determine the Easter calendar dates, visit the Astronomical Society of Southern Australia's webpage, ASSA.

SOURCES:

¹ http://www.assa.org.au/edm.html#Calculator

² http://www.merriam-webster.com/dictionary/paschal%20full%20moon

³http://www.assa.org.au/edm.html#Calculator

⁴ http://en.wikipedia.org/wiki/Julian_calendar

⁵ http://www.assa.org.au/edm.html#Calculator

⁶ http://en.wikipedia.org/wiki/Gregorian_calendar

⁷ http://www.assa.org.au/edm.html#Calculator

⁸http://www.snopes.com/holidays/easter/earlyeaster.asp

⁹http://www.snopes.com/holidays/easter/earlyeaster.asp