Tag Archives: Easter

From the Tablet: Why is Ash Wednesday So Late This Year?

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This entry is part 61 of 181 in the series Across the Universe

This column ran in The Tablet for the new year’s issue of 2008, when Easter occurred remarkably early, on March 23. It was relatively early in 2016, on March 27th, when we ran it here. This year, it’s about as late as it can be! Early or late, the explanation is the same… and so probably worth running again. Why is Ash Wednesday so late this year? Contrary to popular conception, the Vatican Observatory doesn’t set the date of Easter. (We don’t cast horoscopes for the Pope, or evangelize UFOs, either.) But since Pope Gregory’s reform of the calendar in 1582 marked the beginning of the Vatican’s support for astronomy, we have a historical connection. Our calendars have always been marked by a confusion of days, planets, and gods. Even today, our week begins with the Sun’s day, followed by the Moon’s day and ending with Saturn’s Day. The month (think, “moonth”) was originally based on the 29.5 day period of the Moon, … Continue reading →

A note on the date of Easter

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This entry is part 28 of 38 in the series Diary

Horst Rademacher,  a seismologist at U C Berkeley, wrote to friends of mine there last weekend, asking about the date of Easter: May I bother you with a question, which is probably trivial for astronomers like you to answer. However neither Peggy nor I could find an answer anywhere. Here is the question: Tomorrow (Apr 1) is Easter. According to the classic definition Easter always falls on the first Sunday after the first full moon after the vernal equinox. That makes sense, because today is full moon, which is the first full moon after the beginning of spring. And tomorrow is Sunday, hence Easter. However, today’s full moon occurred at 5:37 am PDT. Let’s assume, the full moon would have occurred at 5:37 pm PDT. Applying the definition above from a purely California perspective, tomorrow would still be Easter. However, if we were in the Netherlands, in Germany or in the Vatican for that matter, this assumed full moon would … Continue reading →

Across the Universe: Redating Easter?

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This entry is part 155 of 181 in the series Across the Universe

This column first ran in The Tablet in January 2016 The archbishop of Canterbury Justin Welby has recently [2016] announced discussions to redefine the date of Easter. Pope Francis and various leaders of Eastern churches have also expressed interest in a common date that all churches would celebrate together. Easter was originally the Sunday following Passover, the first full moon of the Hebrew year. But the start of the Hebrew year varied from year to year. Jewish months, 29 days long, mirror the phases of the moon, and so every three or four years an extra month is needed to keep that lunar calendar in phase with the seasons. After the destruction of the Temple in AD 70, there was no central Jewish authority to determine when to add that month. Instead, Jews of the Diaspora relied on a Greek formula (devised in 432 BC by Meton) to add seven intercalary months over a repeating 19 year cycle. It was … Continue reading →

Holy Week and Easter: The Collision Point of Measured Time!

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How can you reduce your Priest to a stammering ball of confusion with one, simple question? In two weeks, ask him, “Father, what is the date for Easter in 2016?” Unless your Pastor had the good fortune of looking at his Liturgical Planner a year ahead of time, I can almost guarantee his answer will be, “Uuuum… I think its… ah… late March… early… mid… or late April?” The reason this question can stump the smartest of liturgical chumps is because the date of Easter is a collision point between differing approaches of measured time. The calculation of Easter is done by identifying the Sunday that falls after the first full moon after the vernal equinox. Sounds easy enough.  However, given that lunar cycles do not match up exactly with our calendars, we can have a spread of dates for Easter. For Western Christians, those dates can occur between March 22 to April 25. For Eastern Christians, the dates for … Continue reading →