Short Wave - The Search For Ancient Civilizations On Earth ... From Space

Episode Date: August 4, 2020

Encore episode. Sarah Parcak explains how she uses satellite imagery and data to solve one of the biggest challenges in archaeology: where to start digging. Her book is called 'Archaeology From Space: How The Future Shapes Our Past'. See 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

Hey, everybody, Maddie Safaya here. We're hard at work on some new episodes, so in the meantime, we're breaking out an old one that you might have missed. And I'll tell you what, this episode has it all. We're talking space, radar, the search for ancient civilizations, what else could you possibly want? And while I've got you here, if you haven't subscribed to or followed shortwave yet, go ahead and do that right now. Now, for real, go ahead. That way, you'll never miss another episode, like this one. You're listening to Shortwave from NPR.

One of the biggest challenges in archaeology is knowing where to start digging. I mean, there are tens of millions of square kilometers of Earth to explore. Sarah Parkheck is one of the pioneers in a new field of study, trying to solve that challenge. I tell people it's kind of like super fancy Google Earth. It's called space archaeology, although it's kind of more like archaeology from space. If you think of, say, like a Roman villa somewhere in England, and it's beneath a field, and you just have the foundations of the villa left, so bits of stone. You can't see those bits of stone from above the ground, but you can see the plants growing there.

Well, the crops or the plants that are growing on top of the foundations are going to have stunted growth because the roots are going down and they're hitting stone. So maybe the plant life would be a little shorter or a little weaker over that stone. Settle changes like that would be hard to spot unless you had a good view. This exact scenario played out in the summer of 2018. When there was so much of England, that was experiencing drought. Parts of Europe baked in out of the ordinary warm spells this summer.

There were just hundreds and hundreds of archaeological features that popped up all over the landscape because it was so dry. Ghostly outlines of a civilization passed emerging from the moisture-starved landscape. Those outlines are called crop marks. And in the UK in the summer of 2018,

they were all over the place. All these medieval churches and Iron Age hill forts and things that archaeologists didn't even know about showed up. That's because of the technology space archaeologists have that can spot subtle changes in plant life, elevation, even the temperature below ground, all using drones or planes in the air and satellites in space.

So right now, basically, you can zoom in from 400 miles in space and see something the size of an iPad. What a time to be alive. I know, isn't that amazing? This episode, Sarah Parkak on the rapidly, evolving field of space archaeology, and what it's helping scientists uncover about our past. I'm Maddie Safaya, and this is Shortwave, the Daily Science Podcast from NPR. Okay, so first off, Sarah Parkak is kind of a big deal. She's helped uncover prehistoric hominid

fossils in eroded Kenyan lake beds, an ancient amphitheater under an airport in Rome, and in Egypt, which is her specialty. She's uncovered thousands of settlements, including more than a dozen pyramids. Are you tired? Perpetually, but it's okay. She's written about those discoveries, by the way, in a recent book called Archaeology from Space. And yes, Sarah does go to sites and do some real deal dig in the dirt, archaeological excavation, but her superpower is analyzing satellite imagery and data to know where to dig in the first place.

Most of the imagery I use is called optical satellite imagery. So it's data essentially taken from light that's reflected off the Earth's surface, and we're looking for changes and patterns. We're looking for how things relate to one another. And hopefully that will indicate where there could potentially be archaeological sites or features within sites, and then we get to go out on the ground and do survey and mapping and excavate them. When you say you use satellite images, what are we talking about? Where do those images come from and kind of how do you manipulate them? So it's a range of different satellite images.

So if we're interested in looking at really, really large landscapes, we use data from NASA. But if we're looking at very high-resolution satellite images, we use essentially the imagery that you see on Google Earth, which is from a company called Maxar Technologies. The challenge with that data is that we can't see through trees. So if you're dealing with rainforest from Central America or Southeast Asia or forests, say, in New England, then we use a technology. called LIDAR, which stands for light detection and ranging, and that's a laser mapping system that you put in an airplane or a drone or a UAV, essentially allowing you to remove trees and see what's there. In your book, you also explain how archaeologists now have the ability to detect temperature differences below the ground. Why is that? How, first of all, cool. Second of all, how does that work?

And why is that important? So one particular part of the light spectrum that is really, really useful for the work that we do is the thermal infrared. So if you have anything that's buried and is a chamber or a void, like a room, a tomb, a buried passageway, it's kind of like when you go into a basement or a wine cellar, you know, the temperature drops a couple of degrees. So by using thermal infrared,

you can see these very subtle differences in temperature. And if, say, an area shows up lower temperature that's the shape of a rectangle. You're like, okay, there's something that's there that we may need to check out. Right. And it's not like you're like kicking archaeologists out of business, right? So it's like you still end up going in there. It just kind of helps like going in there and digging stuff up and looking at stuff with different techniques. But it's basically just giving you a good idea of like, ooh, there might be something here, right?

Exactly. I mean, the coolest part of my job, I think, is the actual physical excavation and that's so time-consuming. And so what the satellites allow us to do is not just find sites, but also track over time potential threats to them. So whether it's rising water, whether it's urbanization or development, maybe there are other issues that could be affecting the sites. It's a tool that allows archaeologists to help monitor and protect sites. Right. And so you even kind of tried to estimate, like obviously estimating how many more archaeological sites. might be out there. And it's in like the millions, right? Yeah, I think I estimated, and I'm probably, I'm probably not going to give the right number. It's the book, even though it was just the summer,

Sarah, I think it's 50. 50, 50, 50, 50, 50, 50, 50, 50, 50, 50, 50, 50 million. So, yeah, so basically I think something like 40 million, 50 million sites left to find, but like, I could be wrong. It could be 100 million. It could be 10 million. No archaeologist yet has written me an angry email saying, how dare you? So I think, like, I think I was pretty on the mark. Yeah. So there's another thing that I kind of wanted to talk to you because I don't get to talk to that many archaeologists, you know what I mean? But now I've got my own show and they can't stop me, Sarah. That's right. You know what I mean? So can we talk a little bit about how colonialism and archaeology have intersected in the past and maybe how it still does now and what we can do

about that, I guess? That's a big question for you. If it's a big question, and it's something I and my colleagues think about a lot. So first of all, you know, I have to acknowledge that archaeology, especially Egyptology, you know, both those fields as well as anthropology, you know, they have deeply racist, colonialist roots, all of them. You know, Westerners parachute in, do their projects. You know, we're essentially archaeological tourists. That will probably rankle a lot of my colleagues. I don't care. Someone needs to speak out about this. And they leave, which is appalling. You know, I pay guards year-round at the site where I work at Lished. I have very close relationships with the village. My Egyptian core staff, you know, I mean, I speak to them

every single week. And at the end of the day, it's about those relationships. So I think we all have to do a lot of hard stares in the mirror at ourselves and ask, what are we taking and what are we leaving? Are we training? Are we providing equipment and materials? What else should we be doing to create some more parity in the work that we're doing? And I'm not the only one doing this, by there's so many of my colleagues, both in Egypt and elsewhere, are being much more intentional. But yeah, I think we have to ask a lot of hard questions. Yeah. You talk in the book about the importance of discoveries and how a few small discoveries can impact a field more than like a headline worthy discovery, which I really like, because I think as a person, who's, you know, been a part of the scientific process, it's frustrating when, you know, only the big kind of discoveries get credit for changing fields when in reality it is those little findings. You know what I mean? So, yeah, I'll give you an example. A colleague and friend of mine, Afifi Roheim Afifi, is currently leading excavations in an area

near the Valley of the Kings in Egypt. And he and his team just uncovered a new... workman's village. So it's a place where men would have stayed and lived as they were constructing tombs in the Valley of the Kings. And kind of compared to other discoveries, not just in Egypt, but elsewhere, it really didn't get much play. But I think it's one of the most extraordinary discoveries in Egypt in the last 20 years. We only know of one other workman's village on the West Bank in Luxor. It's an unbelievable find because it's going to tell us about the daily life of the people who lived and worked, you know, 3,300, 3,500 years ago.

Right. And to me, it's those discoveries that are most interesting. All right, Sarah Parkak, we appreciate you. This was a lot of fun. Likewise. Thank you so much. Go to bed. I go to bed.

Take an app. Thank you. Thanks to Sarah Parkak. You can read about her work in her book, which is called Archaeology from Space, how the future shapes are past. This episode was produced by Brent Bachman, edited by Viet Le, and fact-checked by Emily Vaughn. I'm Maddie Safaya. Thanks for listening to Shortwave from NPR. Until recently, Edmund Hong says he didn't speak out against racism because he was scared.

My parents told me not to speak up because they were scared. But I'm tired of this. Listen now on the Code Switch podcast from NPR.