Christmas / Easter Switcharoo

By now most people don't expect the Bible to be interpreted literally. And yet, I think a lot of people don't understand why Christmas is on Dec 25. There is nothing in the Bible to suggest the birth of Jesus was in any particular time of the year. But December 25 was a date that already had much significance to pagans. As the winter sets in, the point at which the sun rises (and sets) moves gradually further north. The movement is a sinusoidal oscillation. Like a playground swing, which slows as it reaches the top of the arc, and momentarily stop before switching directions, the spot on the horizon at which the sun sets would seem to freeze for a few days right around the solstice. Finally, on December 25, the human observers could finally detect that the spot had moved south, and the days would start becoming longer again. This was a cause for celebration in a time of darkness.

Similarly, Easter latched onto existing pagan spring holidays, the season of birth. So shouldn't Christmas, the birth of Jesus, be in the spring, the season of birth? And shouldn't Easter be on December 25, the day the sun rises again? The holidays are totally flipped! What do I do? Email the pope? Start putting up Christmas lights in April? How should I proceed?