Time Zones and Doomsday

I just got done reading this rather thorough take-down of the idea that this Friday, December 21st, will be a "doomsday" because a certain cycle of a certain Mayan calendar ends on it on Slate's new really cool astronomy blog. Accordingly, because I need some way of procrastinating on my constitutional-theory paper that's due, well, on doomsday itself, I thought I'd share a thought I recently had about doomsday predictions. If you forecast that the end will fall on a certain calendar date, which time zone do you mean that in? Is it December 21st, Eastern Standard Time? Or Greenwich Mean Time? (In Doctor Who it does tend to be London time, as far as I can tell, though it's usually only relevant for Christmas specials.) Tokyo time? What? Does it happen at the first instant that it's December 21st anywhere on earth, or at the one brief moment, twenty-four hours later, when it's December 21st everywhere on earth? Or just at some point during the day that's December 21st, 2012 for the location of the Mayan civilization? Whenever it happens, it'll be nighttime for half the planet, and while the day is a nice naturally-occurring measurement unit, the placement of the dividing-line between one day and the next is a wee bit arbitrary. Astronomers tend to consider a day as lasting from noon to noon, for instance.

Now, this is certainly not the biggest problem with doomsday prophesies by any stretch of the imagination. Still, worth keeping in mind that there isn't even a uniform date across the whole planet, let alone a uniform time. And if we're talking about a fated planet-wide Armageddon, you'd think it would have some slightly more eternal reference-frame than just the dating conventions of twenty-first century human civilization. Just a thought.