Video:Why do Easter Dates Change Each Year?with John DeMike
Easter dates rely on a mixture of solar and lunar calendars, which have been adjusted over many years of observing the holiday. Learn the history about why Easter dates change and how different religions base their calendar.See Transcript
Transcript:Why do Easter Dates Change Each Year?Why Easter falls on a different day each year. We have several reasons for this: First is the fact that the exact date of Christs resurrection was never actually recorded, except that we know that it took place after the Jewish Passover. The problem with Passover is that it was, and still is, correlated to the ancient Hebrew calendar, which was somewhat inaccurate, and was based upon a combination of Solar and Lunar movements.
Religious Calendars are Different and Easter Dates Change over the YearsWhile this was taking place, the Romans were using the Julian calendar, which is based strictly upon the rotation of the Earth around the Sun, and completely ignores the positions of the Moon. So because Passover is based upon the sighting of the full moon, and because our dates are based upon the Earth going around the Sun, and because the moon moves independently from the Earth and Sun, Passover ends up having a moving date each year, which means Easter has a moving date each year.
Easter is Based on the Gregorian Calendar for Western ChurchesTo make matters worse, the early churches each made up their own schedules, and although they celebrated Easter after Passover, it was on all different days of the week and varied from church to church. In an attempt to standardize all this, in 325 A.D. the Roman Emperor Constantine made the official decision that Easter shall be celebrated on the first Sunday, after the first full moon, which occurs after the Vernal Equinox, as observed from Jerusalem. This took care of Passover and Easter not sharing the same date, and made it easier to calculate all the Easter dates in the future. However, the Julian calendar is off by about 11 seconds per year. So by the year 1582 we were off by about 10 days. To correct this, Pope Gregory the 13th gave us the Gregorian calendar, which is an update of the Julian calendar, and its the one that we use today.
But the Orthodox Church still uses the Julian calendar to calculate their Easter dates, and they use actual astronomical observations to determine the full moon and the Vernal Equinox. Meanwhile, the Western church uses the more up-to-date Gregorian calendar, which fixes the equinox date at March 21st each year, but their full moon dates are base upon their own tables, and can vary by as much as 2 days from the astronomical full moon. So thats why we have so many different dates for Easter each year.
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