By Gina Gaudet
Astronomy of Easter
As this will be read before Easter, I thought it would be
interesting to look at the history of the most changeable
holiday of the year. Anyone who has raised children has likely
had to explain why Easter is not the same date or Sunday every
year. The easiest and most basic explanation is that Easter
falls on the first Sunday after the first full moon after the
first day of Spring (which is around the 21st of March).
Our universe is so immeasurable that our orderly calendars are
sadly inadequate for documenting vast quantities of time or
space; we often have to manufacture computations that make sense
to us. To further complicate things, Jesus was Jewish, and
Jewish tradition follows a lunar calendar. The Christian
calendar is a solar one. (Lunar calendars follow moon cycles,
which are shorter than sun cycles). Are we having fun yet? I
know I am.
The history that is available to us through the gospels tells us
that Jesus was crucified on the day after the feast of the
Passover. The Passover commemorates the liberation and the
Hebrews’ escape from slavery to the Egyptians. The communion
service that generally initiates the sacred three days that
Christians observe as a memorial of the last supper, which was
the Passover feast that Jesus observed with his followers before
his arrest. This happens on Maundy Thursday.
Because the Passover is a Jewish holiday, we schedule Easter
(Jesus’ resurrection) to coincide with the third day of Jesus’
death. This is another source of confusion, because Jesus is
said to have risen on the third day after his crucifixion, which
is observed on a Friday. Which is two days before Sunday. Go
figure. Here we need to understand the Jewish observance of days
as beginning at sunset the prior evening (see Genesis 1:5, 1:8).
So according to the calendar above my desk, on Wednesday, April
5, Passover begins at sundown. So Jesus feasted with his
disciples on that evening.
After the last supper they went with Jesus to Gethsemane, where
he sought solitude in order to pray as he anticipated his
arrest, trial and death. He was arrested that night (still the
Passover). If the timeline holds, his crucifixion would actually
take place on the day after (which begins on Thursday at
sunset). So he would have died in the daytime after the
Passover, which would be the first day of his death. Which would
make Good Friday evening, after sunset, the second day of his
death. And Saturday evening would begin the third day of his
death. Thus, his resurrection is observed on the third day. The
women come to the tomb first thing in the morning, because the
observed Passover is officially over. (To attend to a dead body
legally renders one unclean and so these rituals could not be
observed until the holy days of Passover were ended).
So, to return us to the purpose of this exploration, we now
understand why Easter is observed on a different date every
year. The events leading up to Easter are measured on a lunar
calendar. And we see how our timeline is a little confusing
since we are translating from a lunar calendar to a solar one.
And we also know why Christian folk worship on a Sunday morning,
and Jewish folk on a Saturday evening (the beginning of the
We observe Easter on a solar morning after a lunar festival, on
a little planet orbiting a light for our days, and orbited by a
light for our nights. So, whatever and whenever you celebrate,
may your holiday be blessed with light!