In the early Church there were various traditions that arose for when the date of Easter would be each year.
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After a few hundred years of confusion, the Holy See finally made a decision, to establish the official date of Easter in the Roman rite and therefore in the Western Church, as being defined as the first Sunday following the first full moon of spring. If the first full moon occurs at 23:59:59 Saturday evening, Resurrection Sunday follows in one second. If it occurs at 00:00:01 Sunday morning, the Feast day is delayed by one week.
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This is to assure that Holy Week and therefore Good Friday never takes place during a new moon, making it impossible for a solar eclipse to happen on Good Friday, and discouraging the erroneous fable of the darkness during Our Lord's crucifixion to have been due to any natural event such as an eclipse.
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The Miracle of the Sun that occurred on October 13th, 1917, was not due to any natural cause, either. And we can easily see that what everyone saw on the first Good Friday was equally inexplicable by logic or reason. It was truly a stand-alone miraculous 3 hours.
Today you can find all manner of explanations of what the Second Coming will be caused by or how it will occur with many and sundry ideas about how all the prophesies can be fulfilled using everyday ordinary means. Forget it. When Our Lord returns it will be utterly unheard of, what happens, and nobody will be able to anticipate it or do anything about it.
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