Hank Green: Hello time travelers and any other people living in the future. If you're watching this, it means that the Maya -- as they often are -- were right, and Hollywood -- as it almost always is when it comes to science -- was wrong. [SciShow intro] I'm talking, of course, about the Mayan calendar, and the winter solstice of 2012. As you've noticed, Hollywood shysters, along with some cable TV people and a good number of pseudoscientists authors are trying to convince the world, that maybe, it's all going to end on December 21, 2012. The Earth is going to split in two, or the poles are gonna shift, or house cats are going to rise up against us and make us poop in boxes of sand. And they're all feeling that way because of a particular significance that a particular ancient civilization put on that very date. And if you're watching this video after December 21, 2012, well, you may have to feel a little bit embarrassed about getting all wee-wee'd up about it. Now I'm not saying that December 21, 2012 isn't an important date on the Mayan calendar, it certainly is. DON'T panic, I can personally guarantee that the world is not going to end on December 21, 2012. And here is just one of the reasons why. It's not even that I don't even believe that the world is going to end, it's that the Maya didn't. The Maya had lots of different ways of measuring time. And one of them was especially for measuring very long periods of time. Because unlike you and me -- who can't remember life before Tomb Raider: Underworld -- the Maya had a really long view of time. And they measured it using what's called the Long Count Calendar. So check this out. The Maya called a day a k'in. Twenty of these k'ins -- twenty days -- were called a winal. Eighteen winals -- or 360 days -- made a tun, or about a year. Twenty tuns were known as a k'atun, or about 20 years. And twenty k'atuns make a b'ak'tun, which amounted to 144,000 days, or about 394.26 years. Wow, this sounds like Klingon. The Maya used this system to count the number of days since what they called "the last creation." Yeah, I said "the last creation," because the Maya believed that we're currently living in the fourth creation. The first three, the gods screwed up or whatever and they wanted to start over. Believe it or not, some scientists actually did the math backwards, and they figured out that the date of the last creation was 3,114 BC on August 11th. I mean you gotta start somewhere, right? So here's how the Maya marked time from that day: you start with the number of b'ak'tuns (or 144,000-day cycles) that have passed since creation, then, to get a more specific date, you put on the number of k'atuns (or 20-year cycles), then you add the number of tuns (360-day cycles), then the number of 20-day winals, and finally the number of days. And hey, look! I could show you my birthday, May 5, 1980, according to the Mayan calendar. And here is what July 4, 1776 looks like. And finally we have what December 21, 2012 looks like. Yep. That is it, a 13 and some zeroes. December 21, 2012 is the day when the Mayan calendar clicks over to the next whole b'ak'tun. And do you know what happened the last time this happened, the last time we clicked over to a whole new b'ak'tun?! NOTHING! No kidding. The last time this happened was September 18, 1618. An auspicious date known for absolutely nothing happening on it. I've got a history of everything that happened on every day in history, and let's see what we've got... we've got ahhh... the Spanish crown reinforced its garrison in Puerto Rico. That is the only thing that we could find in any history book about what happened on that day. Now, it is true that the Mayans believed that the last creation lasted for exactly 13 b'ak'tuns. So that's probably where all of the hysteria is coming from. But there's nothing in all of Maya lore that says that the calendar will stop, or that creation will cease, or any mumbo jumbo like that. If anything, people who study this say that it probably would just be an occasion for some noisemakers, and singing auld lang syne, and getting really drunk, and hooking up with that hot housewife who lives two doors down from Chichen Itza. It's basically just Y2K for Mesoamericans. So, yes, I'm afraid you do have to finish that term paper, and file your taxes, and remember your sister's birthday, and continue paying off your student loans. The Mayans would've wanted it that way. Thanks for watching this episode of SciShow. It's great to know that we're not all gonna to perish in a burning ball of flame next year. And that's the kind of news that we like to bring you. And if you want to hear more of it, you should subscribe if you haven't already. If you have any questions or ideas you can hook up with us on Facebook or on Twitter, and always we'll be down below in the YouTube comments where we love to see you. Goodbye.