So how did the Mayans come up what their calendar? It's a bit complex, but here is a greatly simplified explanation. (Of course, if you see I'm wrong here or have oversimplified things a tad too much, please shoot me a post and I'll see what I can do.)

Okay, so this is where it all started. This is what is known as Monument Six, a massive stone tablet that was found at an obscure ruin in southern Mexico during highway construction in the 1960s.

Cool, huh? The stone tablet almost didn't survive; the site was largely paved over and parts of the tablet were looted. However, what survived shows that "something" is supposed to occur in 2012 involving Bolon Yokte, a mysterious Mayan god associated with both war and creation. Unfortunately, erosion and a crack in the stone make the end of the passage almost illegible. That, however, never stops a determined archeologist, one of whom, Guillermo Bernal of Mexico's National Autonomous University, interprets the last eroded glyphs as maybe saying, "He will descend from the sky."

Spooky, perhaps, but Bernal notes there are other inscriptions at Mayan sites for dates far beyond 2012 - including one that roughly translates into the year 4772. But this doesn't explain how the Mayan's came up with their December 21st, 2012 date. Okay, but before we go there, we need to know a little about the Mayans.

The Mayans were an indigenous race of people who populated the area we know today as southern Mexico , Guatemala, and El Salvador from roughly 1800 BCE until around 900 CE. Though the Mayans flourished in the Americas for over three thousand years, their "golden age" occurred between 250 and 900CE, at which point they were one of the most densely populated and culturally dynamic societies in the world. Known for possessing the only fully developed written language in pre-Columbian America, the Mayans were also famous for their spectacular art, monumental architecture, and sophisticated mathematical and astronomical systems making them, in many ways, as advanced a society as that which existed in Europe at the time. They even built irrigation systems and developed building techniques as dynamic and articulate as that of ancient Rome and that could even be considered almost modern by our standards today. Then, for reasons still debated among archeologists today, around 900 CE they abruptly abandoned their great cities and, though they never entirely disappeared (the Mayan language is still spoken in some parts of Mexico to this day) by the time the warlike Aztecs came along in the late 1200's, they had all but gone, leaving only crumbling but still magnificent ruins to mark their presence.

It was their advanced understanding of mathematics and astronomy, however, which is the most impressive aspect of these remarkable people. The Mayans were famous for producing a series of calendars to track various lunar, solar, and earth cycles with remarkable precision and accuracy. These calendars acted like a type of harmonic calibrator, linking and coordinating the earthly, lunar, solar and galactic seasons in an aesthetically simple and elegant manner. In fact, their calculations proved to be so extraordinarily accurate that they are capable of impressing us with their skills even today, and it is these calendars that have end-times aficionados intrigued and remain the source of so much speculation.

How they work is fairly complex, but not indecipherable. Basically they used three different dating systems in parallel, the Long Count, the Tzolkin (divine calendar), and the Haab (civil calendar). I won't go into all the details about how each works but suffice is to say that they each use very different dating cycles than does our modern Julian calendar. For example, the Tzolkin has weeks of two different lengths, one a numbered week of 13 days and the second a week of 20 named days, while the Haab calendar consists of 18 months of 20 days each, followed by 5 extra days, known as Uayeb, giving the year a length of 365 days. Long time periods are measured by means of the Long Count, in which one 360-day year (a Tun), consists of eighteen 20-day months (known as Uinals). Twenty of these Tuns makes a Katun; twenty Katuns a Baktun (nearly 400 years); and thirteen Baktuns a "Great Cycle" of 1,872,000 days or about 5,125 years. Got it? Me neither.

Now the problem comes from the fact that, at least according to the Mayans, there are five Great Cycles in all, which when combined denote the history of time (from their perspective). Scholars who have studied this calendar in detail have been generally able to agree that, as best they can determine, the last Great Cycle began on the 11th of August in 3114 BCE, and is set to end on the 21st of December 2012 CE ( in the Long Count) thereby finishing off the Mayan's 26,000 year, five cycle calendar. Now what's most interesting about this is that at around 11:00 PM Greenwich Mean Time on that date there will be an extremely close conjunction of the Winter Solstice Sun with the crossing point of the Galactic Equator (Equator of the Milky Way) and the Ecliptic path of the Sun. This is something that happens about once every 26,000 years, making it a big deal (as well as marking the end of time-at least according to some).

The implication here, at least to some people, is that the end of this cycle was interpreted by the Mayans as being synonymous with the end of time or, at very least, a period marked with major changes to the planet, both physically and spiritually. However, there is no evidence that the Mayans believed that at all. While doubtlessly the Mayans would have interpreted this to be a significant event, that doesn't necessarily mean they considered it a time of catastrophic changes. They would have had spiritual significance to be sure, but there is nothing to suggest the Mayans considered such a change to be apocalyptic in nature. Unfortunately, it appears to be a common human trait to interprete such specific date-setting in generally apoclyptic terms, resulting in many people seeing the end of the Mayan calender and December 21, 2012 as the end of time rather than just the last day on an ancient calender. Of course, since some 150,000 people die on this planet each and every single day, for a small percentage of the population December 21, 2012 really will be doomsday, so the prophecy isn't entirely wrong. It's just applicable to a few unfortunate souls rather than to all of us, which should be of comfort to most of the planet's 6.7 billion souls.

See you in 2013!