is it not impossible for Christ to be conceived during Great Lent, because there was no death of Christ before the birth?
Or, is this one of those God exists outside of spacetime questions
No, this is one of those commemorating events spaced out over 33 years within a single year questions.
Feast of the Annunciation (Anniversary of Christ's conception)- March 25 (during Great Lent)
Feast of Nativity- December 25 (Nine months later)
Good logic, but you've got it backwards. The Feast of Annunciation is calculated based on the day of the Nativity, not the Nativity based on the day of Annunciation. So we start with December 25 or January 7 and count back 9 months of human gestation, and there you have it. A major feast day falling in Lent.
I had arranged the dates merely for ease in calculating the 9 months (it being easier to count forward with the months for the same reason it's easier to count forward with the alphabet, we're used to saying "January February March"), not for the way at which the determined dates were reached (which seemed pointlessly confusing for a quick response to an already confused person).
If had wanted to get really
technical I could have pointed out that the Church New Year is in September, so the Nativity always
precedes the Resurrection, and the real
question is how can Christ be conceived after
He is born. It was tempting at the time, but also seemed pointlessly confusing (and not just a little smarmy).
a) No, it doesn't always fall within Great Lent, but it usually does.
Though for those of us on the New Calendar it pretty much always does. The only way for the Annunciation to fall outside of Lent is for it to occur after the Pascha, something impossible when the Pascha must happen after April 2.