Short Wave - The Key To Uncovering An Ancient Maya City? Lasers

Episode Date: August 18, 2023

Today we enter into the plot of a summer blockbuster adventure movie. Regina talks to NPR reporter Emily Olson about the recently uncovered ancient Maya city, Ocomtun. The large site, which researchers found using LiDAR technology, even seems to have "suburbs," flipping their expectations about how robust the Maya civilization was — and where it was. Read Emily's full story here.Have a science mystery to share? Email us at [e-mail] pcm.adswizz.com for information about our collection and use of personal data for sponsorship and to manage your podcast sponsorship preferences.NPR Privacy Policy

You're listening to Shortwave from NPR. Hey, shortwavers, Regina Barber here with beloved co-worker, new to Shortwave, Emily Olson. Hey, Gina. Hey, Emily. So you report on a wide range of topics for NPR, some scientific, some political. What are you bringing us today? That's right. Yeah.

Today I'm bringing you a story about something deep in time, the ancient Maya. And I do mean Maya, which refers to the people and not Mayan. which is talking about the language. The Maya are pretty cool, but honestly, I don't know much about them beyond they first became a civilization thousands of years ago in Central America, and I probably come from them. I mean, that makes a lot of sense. Some Maya populations are still around today. But when we're talking about the ancient Maya, we're talking about a civilization that thrived from roughly 250 BCE to 900C.E. They dominated the Mesoamerican region, think like Southern Mexico.

Mexico, Guatemala, Belize, Honduras, El Salvador. But this story is about one particular slice of that region, the central Yucatan Peninsula in Mexico, the southern part of the state of Kempete. Okay, so that's a place I don't know too much about, actually. Right. I don't blame you. It's not exactly a common tourist destination. I mean, it's super dense jungle, but it's not as lush as other tropical regions. It can be relatively hot and dry. But there's one person who's been spending a lot of time there, and that's archaeologist Ivan Spraic. Everything is overgrown, and it's completely uninhabited. So there are some trains or dirt roads which penetrate the area and are occasionally used by log workers or hunters, but they are often. And he keeps wanting to go back.

Why does he keep on wanting to go back there if it's such an isolated area? Well, he's looking for evidence that the ancient Maya lived there, which, until the last last few years, honestly, it would have been a little laughable. Really? Yeah, most Maya settlements are concentrated around the coast or on the highlands. And for decades, archaeologists thought the landscape here, this far inland, it would have just been too harsh. But then in May, Ivan and his team found something incredible, not just like a little bit of

evidence, but what they think is a whole city. Wow. A site they're calling Akam-Tun. We saw that some structures were truly massive. and we knew that that concentration of structures which relate and named Okomtun must be an important site. And if Ivan doesn't sound too excited there, it's because he actually wasn't very surprised to see this stuff in person. Part of that is just Ivan's personality. His colleagues call him the real-life Indiana Jones.

But without like the stealing and stuff? Yeah, exactly. Ivan has been doing this for decades and he's been to dozens of archaeological sites. But another part of it is just that Ivan had already seen this site on a map, so he knew that something was there. What do you mean he's already seen it on a map if researchers had just learned about its existence? So it all has to do with lasers. Today on the show, grab your adventure gear because we're going to enter into a plot that could be an Indiana Jones movie, finding a lost city in the Yucatown. We talk about how this discovery is rewriting our narratives of the ancient Maya, how lasers are pushing archaeology forward.

And why? Despite this technology, researchers like Ivan still have to check through the jungle. You're listening to Shortwave from NPR. Okay, so, Emily, you have this big reveal that researchers found this lost city, Akam-Tun, in a remote part of the Yucatan Peninsula using lasers, which is so cool. Please tell me more. Okay, yeah. Let's back up for you. a second. So historically, Western archaeologists would be led to a site by locals, or sometimes archaeologists would discover ruins accidentally, like the botanist Cyrus Lundal, who identified

the pyramids of calachmal from, get this, the window of an airplane. Awesome. But these days, the process is a lot more intentional, and it starts with Google Earth. That sounds about right, because Google controls my life. Yeah, exactly. Researchers, start by analyzing satellite imagery that's pretty widely available these days. And just from that, they can sometimes start to spot artificial shapes in the area's greenery. You know, maybe it's a raised circle in the vegetation here or a suspiciously rectangular reservoir there. And in the case of finding Occam Toon, researchers were able to identify four zones in this one particular region that looked ripe for further exploration. And so they took those zones and applied the next step,

which is LIDAR. Yes, I love LIDAR. It's so cool that you can basically shoot lasers out, collect all this info about an area based on how long it takes the light to bounce back. And I know it's used for all sorts of stuff like Noah uses it to map coastline erosion. iPhones use it for better photos. And police even use it to catch people speeding. Gina, you're a pro.

For anyone who doesn't know, LIDAR stands for light detection and ranging. And for archaeology, it's letting people get a literal lay of the land, but remotely. One of the engineers who's using it a lot when it comes to archaeology is Juan Carlos Fernandez Diaz. He's with the University of Houston. And he told me that the technology they're using in the jungles of the Yucatan, it's pretty impressive. For this particular project, every second we sent almost half a million laser pulses to the ground. Wow. Every single second.

Basically, Juan and his team went up in an airplane three separate times. And for about four hours each time, they just flew back and forth and neat rows over an area that's about 180 square miles. He described it like mowing the lawn, basically. That sounds like a lot of work. And it is, but Juan says the real work actually happens after that. The big engineering happens in the lab where we actually process these points. and we can basically separate the returns that were coming from trees and the returns that were coming from the ground. And then it's when we create like a three-dimensional map.

And this is when archaeologists start to get really excited because they can use these differences to visually strip away the trees, kind of like digital deforestation. Oh. And they can reveal the human-made structures underneath. Okay. So revealing human-made structures, super cool. But where does Ivan come back in? Right.

Yeah. He comes in right about here. because once a site is mapped, it still has to be verified the old-fashioned way in the field on foot. And Ivan, he loves a challenge. This is the one step that he lives for. Take Occam Toon, for example. It's only about 30 miles away from the nearest road, but it took his cruise two weeks to get there because they had to clear a path, you know, with machetes and chainsaws and haul over a bunch of supplies and water. That couldn't be me, honestly. But what did Ivan? even see when he got there? Well, the first thing that surprised Ivan was the size of the structures themselves. When we came there, we saw that the structures, some structures were truly massive.

The largest construction is an acropolis, a big platform, about 80 meters in length, about 10 meters tall. And on top of that platform, there is another pyramid about 15 meters tall. He said there was also a platform of concentric circles and squares all inside each other, which may have housed like a marketplace or been a site for cultural ceremonies. Wow. And then there's the reason that Occam Toon is named Occam Toon. And that's because Ivan and his team found a bunch of cylindrical shapes stones on the site. And Alcumtun is the Mayan name for column.

And it sounds cooler if we find a name which is in Maya language. Right. And it's a tradition in Maya. So could objects like that tell us anything about the age of the city? They totally could, yeah. These columns in particular are similar to ones that archaeologists have seen at other Maya sites. And so that makes them think, okay, Akamtoon was probably built in the late classic period between the years of 600 and 900 CE. But then Ivan said there's other objects, like some fragments of ceramics that they found and they took back to the lab.

Ivan says those appeared to be even earlier, maybe around 1,000 BCE. So that got Ivan thinking. If some of that ceramics is from the early first millennium BCE, then that would be one of the earliest sites in the central Maya Lowlands. That's exciting. Right, but there's even more. The team found these irregular mounds of dirt on top of the Acropolis that contained all these small figurines.

And Ivan said that those kind of figurines were characteristic with later periods, like the mounds might have been placed there as offerings to earlier generations. So that would mean people may have been living in Occam Toon in the post-classic period, possibly even right up to Spanish conquest in the 16th century. I mean, that's really recent. And you're saying Occam Toon didn't just exist briefly in the late classic period. It endured. Yeah. Maybe for as long as 1700 years. Wow.

Okay. That's a long time for a city. Yeah, especially for one in such a harsh landscape and without any modern technology. It's worth emphasizing, too, that it's not like Occamtoon is just in a vacuum out there alone in the central Yucatan. Like with any city, it appears to have suburbs. All along the trail, we were seeing mounds and some concentrations of structures, but we cannot check every single mound because there are too many. There are a lot of major and smaller settlements.

So there's a lot more to explore. So basically, archaeologists went from thinking the central Yucatan was too harsh to develop to finding a whole city and its suburbs, all thanks to lasers. I wonder if Ackhantun is changing the way we think about the ancient Maya as a whole. That's a good question, Gina. I mean, less than a decade ago, archaeologists thought the population of the ancient Maya numbered around 7 million, maybe, at their peak. But already, they had to raise that estimate to $11 million in 2019 based on some research with Lider in Guatemala. And so now Alcom-Tun is making them think maybe they'll need to revise that estimate again.

Wow. So more than $11 million? Yeah. Researchers may have just underestimated how much the ancient Maya were able to grow and expand their population. And maybe there's a lesson in there for us today as well. What do you mean by a lesson for us today? I asked a few researchers about what we could learn. And one of them was Simon Martin. He's a Mayanist script scholar who works at the Penn Museum. And he told me the site shows that the Maya clearly figured out how to farm sustainably without much technology. Millions of people lived a sustainable life in areas which are considered to be, if not uninhabitable, then certainly really very poor landscapes.

So they made it a success. They were able to support a growing population in that environment by developing and using. agricultural strategies which were sustainable and very, very productive. So this is something that we have to constantly now turn our attention to is exactly how they did that. So there are lessons like this about what kept the Maya thriving, but also we can learn something about what caused this very successful civilization to perish. I mean, Ivan said that a bunch of Maya settlements were abandoned in the 10th century due to a mix of warfare and big changes in climate, such as drought.

Yeah, that sounds a little familiar. Yeah, I think so too. Those are the same kind of existential threats we're facing as humans today. Well, will we ever get to find out what happened to the inhabitants of Occam Toon? Maybe. Okay. I mean, another team still has to come in and do the last step, which is also the step that tends to teach us the most about a site. and that step is excavation, a process that often takes years.

It requires a lot more funding and government permission. And right now, it's unclear when that work will start and who will lead it. But in the meantime, Juan and Ivan are already looking at their data from the last flights. And Juan told me they may have some very exciting news for us soon. Oh, okay. He says they've started a running joke in the archaeological community that works in the Yucatan. If you throw a dart at the map, chances are... You know, wherever the dark hits, there will be my settlement.

So there will be more to come from the other three zones that they've mapped. And that's only what they were able to map this time around. Thank you so much, Emily, for bringing us the story. Oh my gosh, of course, Gina. Anytime. We'll put a link in our episode notes to read Emily's full story. This episode was produced by Burley McCoy. It was edited by our managing producer, Rebels.

Rebecca Ramirez, and it was fact-checked by Emily. The audio engineers were Michael Cullen and Josh Newell. Special thanks to Rosemary A. Joyce of the University of California, Berkeley, and Scott R. Hudson of the University of Kentucky. Beth Donovan is our senior director. Anya Grunman is our senior vice president of programming. I'm Regina Barber. Thanks for listening to Shortwave from NPR.