The world as we know it (always a dicey proposition) will come crashing to an end in 2012, we have it on good authority. Something like a mystery planet will come hurtling out of nowhere, or a neighborhood near there, to smash Earth into nothingness. Which, on the whole (not that that word seems appropriate), sounds a lot like Nebraska.

Of course, some prognosticators predicted the mystery planet would come hurtling, etc., in May 2003, and, well, that most likely did not occur. Or maybe the mystery planet did obliterate the Earth in May 2003, and word has just been slow to get to Iowa. Word is so often slow to get to Iowa.

And the good authority we have for this apocalypse is the Mayan calendar, which, according to self-appointed experts, has the bad manners to stop at Dec. 21, 2012.

Why, you wonder, is anyone paying attention to the Mayan calendar now when no one has paid much, if any, attention to it in the past? I mean, have had you ever heard of the Mayan calendar until the last few months? (No cheating.)

I thought so.

Besides, why the ancient Mayan calendar? Why not the ancient Egyptian calendar? Or the ancient Chinese calendar? Or the Western calendar before around 750?

Sometime around 750, I think, if I’m remembering Stephen Jay Gould’s essay correctly, the pope had the Western calendar changed because it was so out of whack. Unfortunately, the Europeans had no concept of the number 0, so AD started with the year 1, which has led to all sorts of problems with when decades start and end, and when centuries start and end, and when millennia start and end. If that weren’t bad enough, the pope had to change the Western calendar again around the mid-1500s — it jumped ahead by 11 days in September.

Which led to rent riots, because some landlords wanted a full month’s rent, but people didn’t want to pay for 11 days that never occurred. A problem, you have to admit.

An interesting side note to all this calendar chaos: The English, because Henry VIII was on the outs with the pope, did not jump forward 11 days. At least not for another 200 years. Which is why George Washington always celebrated his birthday on Feb. 11, not Feb. 22, which is what we, of course, know Washington’s birthday to be.

Confusing enough? Yeah, I’d say so.

But you have to admit — if old calendars have such a checkered past, it seems a bit, well, silly, to expect the end of the world based on an old Mayan calendar?

Oh yes, I am well aware that there’s a quite popular movie out, called catchily enough 2012, that apparently is all about the end of the world.

(Personally, I always thought the world would come to an end if Sarah Palin ever wrote a book. Either I was wrong, or Sarah Palin has never written a book.)

But if the world is going to end in 2012, why in the world are we arguing so much about health care? I mean, it seems a little bit beside the point.

And should we be concerned that the Senate has confirmed so few of President Obama’s nominations for judgeships? (If you’re keeping score at home, only six of Obama’s nominations have been confirmed, according to David Savage of the Los Angeles Times. He notes that George W. Bush had 28 judges confirmed in his first year, and Bill Clinton had 27.)

Savage’s article puts the blame for so few confirmations on the Republicans refusing to allow votes to occur. Apparently, the Republicans have changed their nickname to G-No-P.

But if the world is going to end in three years, who cares how many federal judges we have.

Dec. 21. Man, is that going to put a crimp on the Christmas shopping season.