Y2K Mesoamerican Style
OOOOOOO, spooky. Get a grip. It is a date at the end of a numeric cycle called a b'ak'tun in one of the Maya calendric systems with no more significance than the turn of the millennium (What did you do for Y2K?). Although I am of the opinion that it is correct, in point of fact, it is not even certain that Mayanists have figured out the correct corresponding date to match that particular system to the Gregorian calendar, our modern dating system. Plus, there are several other calendar cycles that were used by the ancient Maya along with many other Mesoamerican cultures and I am not sure that any of them have significant conjunctions with the Long Count date on that day. It just seems more mystical because it is tied to such an exotic culture that carved dates in stone and gave them significance. What is that day's date on the Jewish calendar or the Chinese calendar? I am guessing it falls on a date with no more numerical significance than the date in our calendric system.
It does seem to be true that the Long Count calendar was set up with an understanding of astronomy, including precession and the movement of the sun's position on the ecliptic with respect to the Milky Way. December 21, 2012 is a winter solstice where the sun is aligned with the Milky Way (which don't happen but every 26,000 years or so). However, this is no big surprise. The Maya had sophisticated understandings of the cycles visible in the sky. They were particularly interested in Venus for example and they also had a lunar-based calendar. There are cool calendars all over the world from ancient times where astronomical events were traced. Technological differences do not indicate stupidity. Smart people have been around for tens of thousands of years and even without writing, which the Maya did have the added benefit of, accumulated knowledge gets passed down. It is not that it is an unimpressive accomplishment; it is just that it does not indicate some supernatural understanding of future events. You gotta put 0 someplace so why not pick a day that something cool would be happening in the sky?
Besides, Humanity's existence is an insignificant blip in the universe that will pass without notice. There is no point in getting all worked up about it.