# The Mayan calendar

If you're anything like me, you've looked this up and have been trying to explain to people that just because the Mayan calendar didn't account for leap years doesn't mean the world should have ended some 7 months ago.

But anyway. I've been reading about the Mayan calendar, and I'll attempt to explain it in simple terms.

Basically, the Mayans had a completely different date format from us. They had a system of 5 numbers; 0.0.0.0.0. This system was a lot more inaccurate than the Gregorian calendar, but it seemed to work for the Mayans. Now, you'll probably have heard that the Mayan calendar ends of December 21st 2012. It does. But that's only part of the story. It's only the end of the cycle; the Mayans called it a baktun. It's the first number (that is, the number furthest to the left) of 0.0.0.0.0. 20th December 2012 on the Mayan calendar is 12.19.19.17.19. 21st December 2012 is 13.0.0.0.0. The other numbers, from left to right, are katun, tun, uinal, and kin (or k'in).

Because I'm lazy, I'm just going to directly quote from another website here:

The right-most position is called the k'in, which counts single days: 13.0.0.0.1, for example. The k'in counts up to 19 and then flips back to zero, with counting picked back up by the next position, the uinal. So 13.0.0.0.19 would become 13.0.0.1.0, much like a car odometer.

Each uinal is thus a block of 20 days. The k'in position then picks back up, counting up to that 20, which then gets added to the uinal. So the day after 13.0.0.1.0 would be 13.0.0.1.1 and then 13.0.0.1.2, all the way up to 13.0.0.1.19 and finally 13.0.0.2.0.

The uinals count upward as well. While the Maya generally use a base-20 counting system, Witschey said, they modify this slightly for the uinal, which only counts up to 17 before rolling over to the third position, the tun. Each tun is thus 18 blocks of 20 days, or 360 days — approximately a year by the solar calendar.

Tuns, in turn, count up to 20 before rolling over into k'atuns. As 20 blocks of 360 days, each k'atun translates into 7,200 days, or just less than 20 years. The k'atun place then counts up before rolling over into the final digit, the b'ak'tun.

If that word sounds familiar, it's because Dec. 21, 2012, on our calendar marks the end of the 13th b'ak'tun of the Mayan Long Count Calendar. In other words, it's the day the count will read 13.0.0.0.0. On Dec. 22, it will read 13.0.0.0.1.

Each b'ak'tun is 144,000 days long, or a little less than 400 years. To the ancient Maya, 13 b'ak'tuns represented a full cycle of creation; one carving refers to a god associated with calendar changes returning that day. There are no apocalyptic prophecies, however. In fact, the Maya had several rarely used units that were even larger than b'ak'tuns, giving them the capacity to count millions of years into the future, Witschey said.

Interesting, right? So now you know, and you can hopefully explain to people why the world won't end, or didn't end, on December 21st 2012.

Other sites used:

http://jameswatt.me/2012/03/07/mayan-calendar-and-the-gregorian-leap-year/

http://www.fourmilab.ch/documents/calendar/