Saturday, March 22, 2008

Easter's early this year

The earliest in 95 years, in fact. It was 1913 the last time it was this early -- March 23.The Easter date can never be earlier than March 22 or later than April 25.

(Pictured: African Empty Tomb from

Easter is a feast tied to the cycles of the moon. It is celebrated on the first Sunday on or after the first full paschal moon (vernal equinox), the beginning of spring. Full moon appeared Thursday.

It's pretty early. In the Midwest they're calling for a white Easter. The good news is that we won’t have to complain about it again for 152 years. Yep. Next time Easter is on March 23 will be the year 2160.

It is not the earliest Easter can be celebrated however - that is March 22. It will not be on March 22 until 2285. The last time it was on March 22 was 1818.

So how do we know when Easter comes each year? You'd be better off just looking at next year's calendar and save yourself some trouble.

Until AD 325, Easter coincided with the Jewish festival of Passover. But that year, bishops motivated by anti-Semitic leanings at the First Council in Nicaea decreed that the feast be celebrated on the first Sunday after the paschal, or spring moon.

Antisemitism aside, the bishops also had to figure out how to get all those pagans in the Roman Empire to celebrate Christianity's holiest day, since it was Roman law and all. So, they scheduled it on the lunar calendar to coincide each year with the festival of Ishtar. Ishtar -- Easter. Yeah, fertility rites, bunny rabbits, colored eggs, and all that. Later on, the Irish missionaries fought the lunar Easter, but they were voted down by the Archbishop of Canterbury, so that was how the West was won to a pagan-inspired, lunar Ishtar -- I mean Easter.

So why does the Easter bunny lay eggs? An Anglo-Saxon legend tells of Eostre (Ishtar's cousin they say), the goddess of spring, turned a frozen bird into a hare to help it survive the harsh winter. After a few generations, Dutch settlers in America in the 1700s were telling their children to be good so that the Easter bunny would come and lay a nest of colorful eggs. Who knows why children wanted colored eggs, but they made a lot of effort to get this magical bunny to nest at their house. That's how we got all that plastic green grass and food coloring stains on our clothes. But the peeps were not that bad an idea, come to think of it.

But getting back to this calendar quandary, it's more complicated than you thought. Western churches don’t recognize the astronomical full moon but instead an ecclesiastical full moon based on church charts. The ecclesiastical and astronomical full moons don’t necessarily coincide.

And just to add another wrinkle, the church calculation sets the vernal equinox on March 21. Actually, the equinox is a moment, not a day. Often it falls on March 20.

By contrast, this year the Eastern (Orthodox) Christian churches, using a different formula based on the Julian calendar, will celebrate Easter on April 27.

And Passover is April 19. That's because the Jewish calendar is based on the moon, too, but this year they add a month to their calendar, kind of a leap year month. The month of Nisan, when Passover is celebrated, is pushed forward. In its usual place is a second month of Adar. So Passover this year begins the night of April 19.

It took 12 centuries before a working algorithm was devised to get this Easter dating down pat. Aloysius Lilius perfected it in the 16th Century at the same time he devised the Gregorian Calendar which is still used today.

Just in case you're interested, here's the algorithm used to determine Easter each year:

((19*t+u-w-(u-(u+8)\25)+1)\3)+15)mod30)+(32+2*x+2*y-(19*t+u-w- (u-(u+8)\25)+1)\3)+15)mod30)-z)mod7)-7*(t+11*(19*t+u-w(u- (u+8)\25)+1)\3)+15)mod30)+22*(32+2*x+2*y-(19*t+u-w-(u- (u+8)\25)+1)\3)+15)mod30)-g)mod7)+114)\31

See what I mean? Just look at the calendar.

Sources: The Calgary Herald, Kansas City Star, Daily Mail.