Calendars are more than just systems for measuring days and months.
Every calendar starts with a unique culture that has its own relationship with time, and it represents a system for marking days based on that society's special knowledge of the earth and the stars.
According to a calendar created by the Meso-American Mayan culture, which thrived from about 250 AD to about 900 AD, the year 2012 marks the end of the current cycle of time.
Unlike the Gregorian calendar, which is the currently accepted international norm, the Mayan calendar has a specific beginning and end.
While the Gregorian calendar describes the annual cycle of days during which the earth revolves around the sun, the Mayan calendar describes "long time," or a period of many years that happens to include the modern present as well as the centuries old date when the culture's calendar was conceived.
You could say that the Gregorian calendar is cyclic, while the Mayan calendar is linear.
When you use a cyclic calendar, it's always easy to envision a future that fits into the calendar's pattern: once the days of each year run out, a new year and a new cycle begins.
When you use a linear calendar that has a definite start date and end date, you run into the inevitable question of what happens after the last day.
Is it the end of time as we know it, or does it simply mean that we need to develop a new notation-or a riff on the old notation-that can extend farther into the future? What We Know Virtually all of our information about the Mayan calendar comes from archaeological ruins.
The Mayans had a written language with a complex mathematical system for calculating dates, and it has only been during the past hundred years or so that Western linguists have begun to unravel its meaning.
They have succeeded at deciphering much of the writing inscribed on surviving Mayan ruins.
It is one thing to literally translate words and numbers, and another matter entirely to develop an understanding of the significance of these writings, and their relevance to the modern age.
Mayan calendar notation starts with units of days, or uinals, which aggregate into longer units known as tuns, which are made up of 20 uinals, or 360 days.
When 20 tuns pass, then a k'atun has elapsed, and a period of 20 k'atuns is known as a b'ak'tun.
A b'ak'tun is made up of 144,000 days, or approximately 394 years.
Calculating the present date involves starting at the date when the calendar began, roughly 5125 years ago, and calculating the number of uinals, tuns, k'atuns, and b'ak'tuns that have elapsed.
Alternately, you can start with the current b'ak'tun, and count the number of smaller units that have passed.
According to the Popol Vuh, a collection of creation myths from Central America, the current world began after the previous world ended, having lasted 13 b'ak'tuns, or approximately 5125 years.
The current 5125-year period is the fifth such span in a greater calendar that is made up of five, totaling approximately 26,000 years.
The year 2012-and the date December 21, 2012 in particular-marks the end of a 26,000-year cycle.
What We Don't Know The Mayan civilization did not last intact until the present day, but rather began its decline around the year 900 AD.
Nobody fully understands the reason for its deterioration, although there were most likely a variety of social and environmental factors at play.
Elements of Mayan culture and language do survive among tribes in present day Central America, but the society grew decentralized, and it is unlikely that the cosmology and mythology of these villagers bears much resemblance to that of the scribes who inscribed calendar notations on stone more than a thousand years ago.
As a result of this discontinuity, we really don't have a solid grasp of what the end of the calendar meant to the people who created this system.
It may have meant simply that one phase of history would end and another phase of history would begin, or it might have been associated with predictions and expectations about what the period to follow would bring.
It is also possible that it really did signify an end times, or doomsday scenario, as some modern thinkers have suggested.
The only known Mayan reference to apocalyptic events associated with the end of the period covered by the calendar comes from an inscription at a site in Tortuguero, in Mexico's Tabasco region, which contains a reference to the time in association with the name B'olon-Yokte', which appears to be the name of a god associated with turmoil and strife.
While this does provide some basis for speculation, it is hardly evidence of a widespread, longstanding Mayan belief that the end of the calendar would coincide with the end of the world.
We don't know of any astronomical or astrological events that the Mayans used as the basis of their long calendar.
There is, in fact, a 26,000-year planetary cycle that comes full circle late in 2012: the earth wobbles a bit on its axis over time, so the way it lines up with the other planets in the solar system shifts by one degree every 72 years.
At this rate, it takes approximately 26,000 years for this shift to bring the earth's vantage point around 360 degrees, or back to the point where it started 26,000 years earlier.
Late in 2012, this gradual shift will align the earth's plane precisely with the center of the Milky Way galaxy, a correspondence that has not occurred since the very beginning of the Mayan calendar.
Despite this correspondence, there is no evidence that the Mayans were even aware of this particular planetary shift, or the way it correlates with their calendar.
Although it is a striking coincidence, it is possible that it is no more than a coincidence.
Critics of this theory also point out that the Milky Way's boundaries are hazy, so determining its precise center is problematic.
The Modern Movement During the decades leading up to 2012, a diverse group of scholars, spiritual thinkers, and survivalists have created a cultural phenomenon anticipating cataclysmic events.
In 1966 Michael Coe, who studied Mayan culture extensively and wrote a scholarly book about it, mentioned that an apocalyptic scenario was one possible explanation for the anticipated change that would occur at the end of the Mayan calendar period.
Several decades later, New Age thinkers such as Jose Arguelles and Terrence McKenna speculated more liberally about the meaning of the Mayan calendar's end, and what we can expect at that time.
Their predictions are largely based on the idea that planetary and cosmological events related to the conclusion of the Mayan calendar offer us a window of opportunity, during which we can either take a profound step in our spiritual evolution and create a more advanced and peaceful culture, or we can bring about our own demise by continuing with business as usual, fighting wars and destroying the environment.
The Hollywood movie "2012" treated the impending crisis as a catastrophic series of geological events.
Although the movie wasn't firmly grounded in either hard science or a sophisticated understanding of the Mayan calendar, it did showcase an important truth about the way we are collectively anticipating the year 2012: our actions and expectations are large and dramatic, and they say as much about who we are and how we live as they do about any solid knowledge of Mayan prophesies.
Preparation for the possible events is taking a number of forms.
Folks who are anticipating an apocalyptic meltdown are stocking up on food and water, sharing strategies and ideas, and scoping out safe locations for escape.
Even respectable venues such as the National Geographic channel are posting videos about how to survive.
At the other end of the spectrum, New Age communities are pooling their spiritual resources, hoping to create enough positive energy to shepherd the human race peacefully through the juncture.
Lessons and Conclusions Unlike the doomsday predictions surrounding the Y2K event, the buildup to the 2012 scenarios based on the Mayan calendar are not based on anticipated consequences of an actual event, but rather on interpretations of prophesies.
For folks who take these correlations and coincidences clearly, there is a certainty that something big will happen, although there is no consensus about what form it will take.
It is possible that major changes may occur during 2012, which could be either positive developments or cataclysmic changes.
It is also possible that nothing will happen, or at least nothing dramatic that can be clearly linked with Mayan mythology and cosmology.
One thing, however, is certain: whatever the specific events, the buildup and hype will be nothing short of phenomenal.