Mesoamerican Cultures and the Calendar of the Maya
In recent years, popular awareness of and interest in "2012ology" has been growing. The calendar of the Mesoamerican cultures and the Maya in particular, ends on December 21, 2012. Some people believe this a prophecy forecasting the end of the world or some other event of cosmic significance.
The Maya, in their classical period, had a complicated, idiosyncratic, but overall accurate system of timekeeping. Instead of having a single calendar, they used several systems that operated simultaneously.
The Haab was their 365-day year. It consisted of 18 named months (of 20 days each) followed by an unlucky 5-day period called Wayeb. Instead of adding days on Leap Years to account for the difference between the 365-day Haab and the true length of a solar year, they would simply use a calculation to account for the error. There are several records that mention a 1508-Haab cycle, which is how long it takes the error to add up to a year - 1508 Haab is almost exactly 1507 years (comparable to the error of the Gregorian calendar using Leap Years over that same time). The understanding the Maya had of various astronomical events and ability to calculate when they would occur is vital to unraveling a mystery I'll get to shortly.
Then there is the Tzolkin, a 260-day cycle that used 20 day names that advanced simultaneously with a sequence of 13 numbers (that is, both the name and the number would change from day to day). Because 13 and 20 have no common divisors, the number/name combinations wouldn't repeat until the 260-day cycle was complete. The significance of the length of the Tzolkin is up for debate - some common theories are tied to astronomical events related to Venus, others to the approximate length of human pregnancies. The Tzolkin was important in social and ritual matters.
Together, the Haab and Tzolkin represented the "Calendar Round". Because the systems used different naming conventions and cycle lengths, the current day of both, when taken together, could provide a way to specify a date that wouldn't repeat for around 52 years - long enough to be useful for most purposes.
For timekeeping that required longer duration, there was what we call their "Long Count" system. Rather than operating on repeating cycles, the Long Count was a systematic numbering of days from some start point. The Maya number system was base-20, so that was the basis of most calculations. The lowest level is the Kin, or 1 day. This was followed by the Uinal (20 days), and the Tun (18 Uinal, or 360 days). This breaks from the overall system of 20s, but allows the 3rd place in the Long Count to be a rough guide of years. Next is the Katun (20 Tun, 7200 days which is somewhat less than 20 years) and the Baktun (20 Katun, 144000 days or approximately 394 years). This provides a date that is an absolute count of days from some fixed start point, written as 5 numbers separated by periods - an example could be 126.96.36.199.14 (indicating that 9 Baktun, 11 Katun, 0 Tun, 15 Uinal, and 14 Kin or 1375514 days have passed since the start time of the Long Count).
The fullest use of dates we have evidence for was a combination of all three systems combined the Long Count number with the date given by the Haab and Tzolkin. Unfortunately, this system had fallen into disuse hundreds of years before European explorers came on the scene in the 16th century. Luckily, records of events near that time along with the still-extant Tzolkin cycle allowed scholars to correlate the year of the current Gregorian calendar to a known value for Baktun and Katun in the Long Count. More recently, work done using astronomical texts by the Maya (such as the Dresden Codex) provided data that allowed for finer connection to the point where we now have fair confidence that we can state the current date in the various calendar systems (although there are some who suggest we may be a few days off). This also means that we can backtrack to the date when the Long Count began - our best guess is that 0.0.0.0.0 was equal to 11 August, 3114 BCE (although, it is very likely that the Long Count wasn't in use that long ago, it was simply started at a certain position in the sequence - much like the Julian/Gregorian system was created at year 525). An interactive calendar website can be found here.
Finally, here is where the Doomsday element comes in. Since we now know what the zero-day is, we know the next time the date will roll over to all zeroes in the lower places. This will be 188.8.131.52.0 and it happens on 21 December, 2012. The Maya accounts known as the Popol Vuh, a compilation of different Creation accounts, mentions that the current "world" is the 4th and that the previous one ended after 13 Baktun. This has led some people to believe that the Maya thought that the current world would also end after 13, and various theories related to sunspots, galactic alignment, magnetic field switch, or other astronomical/geological phenomena have been put forward to corroborate this view.
This assumption is absent from the remaining Maya records, however. Many of the astronomical calculations we have include projections well beyond this year. In fact, there is also no reason to believe that the count would stop there and reset to 0.0.0.0.0 - rather the count would run all the way up to 184.108.40.206.19 which would be followed by 220.127.116.11.0.0 the next day using a unit modern scholars have dubbed Piktun (equal to 20 Baktun or 2880000 days, around 7885 years) and even larger units following that.
The significance of 18.104.22.168.0 is more closely tied to the Tzolkin ritual cycle. Due to the way that the Long Count and Tzolkin cycle length interact, this date marks where the combination of the lowest four places of the Long Count and the Tzolkin day/number pair starts repeating. Ultimately, we don't know what the Long Count-using Maya would think of the upcoming solstice, but if it's anything like our Y2K, it would probably mean a lot of celebrating with a small group of doomsayers being drowned out by the crowd.
The ISU Library has several interesting resources on these topics.
Astronomy and the derivation of the various calendars
- Astronomy in the Maya Codices by Harvey and Victoria Bricker, F1435.3 C14 B75 2011
- Time and Reality in the Thought of the Maya by Miguel León-Portilla, F1435.3 C14 L413
- Maya Calendar Origins by Prudence Rice, F1435.3 C14 R53 2007
Exploration of the Maya sources as prophecy/end of the world
- The Mayan Code: Time Acceleration and Awakening the World Mind by Barbara Clow, F1435.3 C14 C56 2007
- The 2012 Story: The Myths, Fallacies, and Truth Behind the Most Intriguing Date in History by John Jenkins, F1435.3 C14 J398 2009
- 2013: The End of Days or a New Beginning? by Marie Jones, F1435.3 C14 J66 2008
- The End of Time: The Maya Mystery of 2012 by Anthony Aveni, QB638.8 A94 2009
- 2012 film directed by Roland Emmerich, DVD 004 524
Rebuttals to the end of the world phenomenon
- 2012 and the End of the World by Matthew Restall and Amara Solari, F1435.3 C14 R47 2011
- Dialogues on 2012: Why the World Will Not End by Christopher Keating, F1435.3 C14 K43x 2011