So, by now you’ve probably heard the “news” that your star sign is off by about a month, or if you’re really lucky (born between November 19 and December 17) that you’re now an Ophiuchus, the, um, snake-carrying guy.

(incidentally, the consensus on pronunciation of the greek Ὀφιοῦχος seems to be “off-ih-YOU-cuss,” but if you’re having trouble, I suggest you go with the Latin equivalent Serpentarius, which just rolls off the tongue and into the heart)

I won’t belabour the points made by others, except to say that it’s surprising how much attention the story has received, given that by all accounts:

a) we’ve known about this for centuries
b) astrologers (at least the tropical ones) will still astrologize exactly as they did before, which is to say
c) your horoscope’s accuracy will continue to depend on nothing more or less than how much you personally want to believe it

So why am I wading in at this (admittedly late) stage of the game?  Well, because the educator in me feels like we’ve missed a crucial chance to learn some nifty science.  It’s not that the scientific explanations of this astrological game-changer which have appeared in the popular press are wrong.  It’s more that they have been rather vague, and more importantly, cut short so that journalists can focus on more important things, like the panicked responses of astrology devotees.

Tellingly, most news stories simply parroted the original quote from the Minnesota Star Tribune:

“The moon’s gravitational pull has made the Earth ‘wobble’ around its axis, creating about a one-month bump in the stars’ alignment.” – Globe and Mail, January 21, 2011

Science-centric sources, predictably, did a better job:

“The Earth is like a wobbly top. As it rotates, its axis swings in a circle, pointing in different directions. As the Earth’s position shifts, so does our perspective of the night sky.” – LiveScience.com, January 13, 2011

One even quoted a Canadian source:

“Precession has shifted our view of the stars significantly over a few thousand years, so the sun is no longer situated in front of certain star groupings on the astrologically appointed dates” – Royal Astronomical Society of Canada president Mary Lou Whitehorne, as quoted by QMI Agency, January 13, 2011

I understand that attention spans are low, and these days, what with the Internet and all, it is possible to piece together the whole story together from snippets like these (or at least wait until an intrepid blogger does it for you).  But at the same time, I can’t help but feel that even after all this attention, most people still don’t have a good understanding of what precession really is.  This is truly unfortunate, as it is public ignorance of this well-established scientific truth started this whole kerfuffle in the first place.

For what it’s worth, I’ve attempted to give such an explanation.  Admittedly, I’m not an astronomer, but I believe it’s pretty accurate, and I hope that it will help clear the cobwebs around some basic astronomical concepts, so we don’t have to go through all this again ten years from now.