Sense of Events Blog takes off his military helmet and dons his ministerial hat today to write about the Star of Bethlehem.
First of all, no, Christ was not born in December.
The real birthday was probably during lambing season in the Spring and some early churches celebrated it on March 25th, but alas a celebration there would interfere with the celebration of Easter, so this date was changed to the date of the Annunciation/Christ's conception, and the feast day moved to December.
I always assumed that putting the feast of Christ's birth around the solstice was one more way of "Baptizing" a pagan holiday: i.e. taking the good part of that celebration (the return of light, the idea the rich serve the poor).
Sort of like All Saint's day here: The family visit to the grave, eating a meal and leaving flowers and candles and honoring the dead has ancient roots in Asia (if you are not familiar with this, watch the recent movie Kubo and the Two Strings). So now the holiday is "Christianized" because we go to mass that day not only pray for their souls but to ask them to pray to God for us.
Since Paul writes not to get your knickers in a know about dates and feast days, it should not be a big thing, but people being what they are, it is.
SoEblog then refers to this site that discusses the Star of Bethlehem, and summarizes what is there, including more links for your reading pleasure.
The "Star" was probably an astrological conjunction that was interpreted by the Zorastrian Magi as the birth of the king of the Jews. This was shown nicely in the movie The Nativity, how when several planets converge in the sky, it appears to be one star.
There is some confusion is about the year of Herod's death Long technical discussion about the controversy here. So Christ may have been born later than the 6 BC that is usually quoted.
the other alternative is, of course, a star that went nova, (see the famous sci fi story The Star). However, more recent knowledge of Chinese records fails to show a record of a nova then, so that has been discarded by most authorities..
more discussion here.
the UKMail has a discussion of a similar conjunction in recent years.
the conjunction here is at 1:18