Archaeology: Unearthing the Past

Host Walter Isaacson and guests dig up the past, talking about the history of archaeology as well as where the field is going now as it incorporates the latest technology into the search for humanity's story.
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In this episode:

  • Wonderful things (0:00)
  • The birth of archaeology as we know it (3:01)
  • King Tut, uncovered (5:03)
  • The trouble with dating (9:50)
  • Decontaminating the past (13:05)
  • A bird's-eye view (16:08)
  • Exploring Angkor (18:32)
  • Putting the AI in archaeologist (23:13)

The modern archaeologist has traded in their leather jacket and bullwhip for satellite imagery and AI tools.

Find out how technology has aided in the pursuit of uncovering the truth hidden underground.

This episode just scratches the surface. Here are some other trailblazers in the world of archaeology:

● Using archaeology to save our seas

● Smart archaeology can help “travel through time”

● Listening to a mummy’s voice

● More about the laser technology from the episode

● How mapping helped archaeologists in a previous episode

“In archaeology we say it's not what you find, it's what you find out.”

— Sara Parcak, professor of anthropology at the University of Alabama at Birmingham

Guest List

  • Brian Fagan is the author of A Brief History of Archeology and a Professor Emeritus of Archaeology at the University of California, Santa Barbara. Dr. Fagan has written many books including People of the Earth and In the Beginning, two widely used university and college textbooks in archaeology and prehistory.
  • Joyce Tyldesley is a professor of Egyptology at the University of Manchester and the author of Tutankhamun: The Search For An Egyptian King.
  • Tom Higham is Archaeological Science and Deputy Director, Oxford Radiocarbon Accelerator Unit. His research interests focus on archaeological dating, including the radiocarbon dating of bone, as well as the chronology of Palaeolithic Europe.
  • Sarah Parcak serves as the founding director of the Laboratory for Global Observation at the University of Alabama at Birmingham. She specializes in satellite archeology and is a National Geographic Society Archaeology Fellow.
  • Damian Evans is a Research Fellow, French Institute of Asian Studies. He uses computational/geospatial methods and LiDAR technology to survey archaeological landscapes. His work focuses on mainland Southeast Asia, in particular those of the Khmer Empire, which dominated the area for several hundred years from the ninth to fourteenth centuries AD.
  • Iris Kramer is a PhD student at the University of Southampton and founder of ArchAI; a startup that uses AI and deep learning to automatically detect archeology using remote sensor data.

Walter Isaacson: Howard Carter knows this is his last chance. It’s 1922 and the British archeologist hasn’t made much of a name for himself in the 30 years or so he spent in Egypt. Bad luck, the great war and his own surly temperament have conspired against the explorer. His own career had once seemed so promising. For 15 years now, Carter has been working under the patronage of the fifth Earl of Carnarvon. The Earl is a ridiculously wealthy Englishman with a passion for Egyptology. Lord Carnarvon has single-handedly funded Carter’s digs in Egypt’s famed Valley of the Kings, the home of the Royal tombs dating back thousands of years. The tombs are elaborate and beautiful, but tantalizingly empty. They’ve been pillaged by looters for centuries. Mummies of ancient Egyptian Nobles have been discovered in the Valley of the Kings, but a fully intact tomb remains the elusive prize.

Walter Isaacson: Carter is convinced that one must still exist, but his excavations have born little fruit; Lord Carnarvon is getting bored. He’s told Carter that this is that his last season of digging before his funding is yanked. It’s his last chance to find the tomb of the elusive Pharaoh Tutankhamun, who’s been dead for more than 3000 years. Carter’s prospects are looking bleak, but then he finds something, a staircase descending into the Valley floor at the bottom of the staircase there’s a sealed door. It’s flanked by two impossibly ancient Royal seals. Carter gingerly chisels away at the door, opening an aperture just large enough to let the candle light in.

Lord Carnavron: “Can you see anything?”

Walter Isaacson: Lord Carnarvon asks impatiently.

Howard Carter: “Yes.”

Walter Isaacson: Carter replies.

Howard Carter: “Wonderful things.”

Walter Isaacson: I’m Walter Isaacson and you’re listening to Trailblazers an original podcast by Dell Technologies.

Speaker 4: Workers carefully chip away at crusts of time.

Speaker 5: The sphinx and the pyramids, guardians to the enchantment of the east.

Speaker 6: There’s a lot of buried treasure down there.

Speaker 4: From the dust of antiquity, archeologists uncover silent remains of its glory.

Speaker 5: Mankind’s age old treasure hunt, into the tombs of ancient Kings.

Walter Isaacson: Human beings, as we know them have walked the earth for at least 200,000 years and our ancestors much longer. But we know only the tiniest fraction of who those people were and how they lived their lives. It wasn’t until the 17th century that curious antiquarians started to realize that they could discover our past by digging it up. But early archeologists were more treasure hunters than academics. It took a new, more scientific minded breed of archeologists to give some rigor and order to the process. For this new breed, archeology wasn’t just about spectacular finds. It was about the small details and objects that tell the story of the past.

Walter Isaacson: One of these innovators was Sir William Matthew Flinders Petrie. He was a true Victorian who made incredibly important discoveries in Egypt. Arguably his most important discovery was the Merneptah Stele, a 13th century BC tablet. That is the oldest existing reference to the ancient people of Israel.

Brian Fagan: This was an eccentric gentleman.

Walter Isaacson: Dr. Brian Fagan is the author of A Brief History of Archeology.

Brian Fagan: He lived in a tomb, but right from the beginning, he did this magnificent survey of Giza, which is still used. And he realized very early on that much of the information about ancient Egypt would come not from spectacular temples, which is what everybody in Egyptology had looked for before. But from in conspicuous finds, like pot fragments, fragments of metal objects and so on.

Walter Isaacson: One of Petri’s, proteges was a young man by the name of Howard Carter, the man who would one day achieve worldwide fame for his discovery of Tutankhamun’s tomb.

Brian Fagan: Howard Carter was by all accounts, a prickly difficult man. He was in fact, a humble man. He came from humble background, which at a time in class conscious Britain made it very difficult for him to be accepted, but he was an absolutely brilliant artist. And he was particularly brilliant at copying things like tomb paintings.

Walter Isaacson: Carter was fixated on his goal of finding an intact Royal tomb in Egypt’s Valley of the Kings for more than a half a millennium, the pharaohs of ancient Egypt had been entombed on the West Bank of the Nile across from the ancient city of Thebes. It was central to their religion that their bodies be prepared in a highly ritualistic fashion and buried with all sorts of valuable possessions so that they could live again amongst the gods. The only problem for modern day archeologists was that after centuries of looting, none of the pharaohs had stayed put.

Joyce Tyldesley: The tombs in the Valley of the Kings were basically filled with Royal burials on the burials of the elite, but they didn’t stay buried in their tombs.

Walter Isaacson: Dr. Joyce Tyldesley is a professor of Egyptology at the University of Manchester and the author of Tutankhamun: The Search For An Egyptian King.

Joyce Tyldesley: The Egyptians themselves emptied the tombs, took away the bodies and recycled the grave goods. So the first archeologists who came to Egypt recognize that the Valley of the Kings had been a cemetery, but they were really, really confused because they were finding tombs and they were entering tombs and when they got into the heart of the tomb, it was empty they couldn’t find anything.

Walter Isaacson: It was one Pharaoh however, whose tomb still remained unaccounted for, King Tutankhamun. His tomb should have been there among his ancestors, but it had seemingly disappeared. Carter was convinced that it was still somewhere in the Valley of the Kings waiting to be found. And luckily he found someone with a lot of money who shared that conviction. George Herbert, the fifth Earl of Carnarvon was an English aristocrat who had decamped to Egypt.

Joyce Tyldesley: Carter and Carnarvon together with a dream team. One had all the experience that was needed and one had the finances that were needed. And they knew that Tutankhamun was missing.

Walter Isaacson: Lord Carnarvon and Carter began working together in 1907, but it would take 15 years before they came across Tutankhamun’s tomb.

Joyce Tyldesley: They were having trouble finding it because the Valley of the Kings is quite large and it’s quite difficult working conditions. And they come to an agreement that they’d have one last look for this tomb, which Howard Carter was still convinced was there. And Lord Carnarvon was starting to doubt it. So it was very much at the last minute where they actually in 1922 found the steps that were leading down to the term of Tutankhamun.

Walter Isaacson: Nobody quite knows why, but Tutankhamun was buried in a small tomb in the Valley’s floor, far from his exalted relatives. One theory has it that he was the victim of a ghoulish grave swap. And one of his advisors stole the spot that was meant for Tutankhamun, but the graves’ humble position meant that it was nearly and quite miraculously, completely intact. Peering inside Carter found more than 5,000 items, including a solid gold coffin, a blade made from meteorite metal, Royal underwear. And of course the mummy of the Pharaoh himself. The discovery was instantly a worldwide sensation.

Joyce Tyldesley: It also had the effect of sparking a huge interest throughout the western world in ancient Egypt. A lot of people started to adopt what we call Niles style and that they started to have Egyptian themed clothing and hair styles, architecture developed a sort of Nile style approach as well. It’s the age of art deco and art deco, the colors and the shapes are very, very similar to the art of Tutankhamun’s period in Egypt. So Tutankhamun was the height of fashion and he became an international celebrity.

Walter Isaacson: For all the astonishing finds that archeologists could dig up in ancient cities. In some ways they were still fumbling around in the dark. It was really difficult to date their finds. When there was a written record as an ancient Egypt or Rome, this was less of a problem, but the more distant past was eternally murky.

Walter Isaacson: It wasn’t until 1946 that a scientist in Chicago truly brought archeology into the atomic age. Brian Fagan.

Brian Fagan: Radiocarbon dating developed by the University of Chicago physicist Willard Libby in the 1940s and 50s, which won him the Nobel prize was probably the biggest transformative agent for archeology ever.

Walter Isaacson: After working on the Manhattan project during World War II. Libby joined the University of Chicago’s Institute for nuclear studies. There, he became intrigued by a discovery made in the 1930s. The discovery established that cosmic rays, which bounce off the Earth’s atmosphere produce an element called carbon 14 or radiocarbon. As radiocarbon permeates the atmosphere, all living things absorb it throughout their lifetimes and crucially, they stop absorbing it when they die. That only do living beings stop absorbing it when they die. Radiocarbon also slowly dissipates over time. Scientists were able to determine that it takes about 5,700 years for half of the radiocarbon to leave an organic object. This is known as its half-life. Knowing this half-life means you can measure the amount of radiocarbon in say a bone fragment or a piece of cloth and accurately establish when the plant or animal had died. This completely changed archeology.

Tom Higham: It held it a revolution in our ability to date the past

Walter Isaacson: Tom Higham is a director of the Oxford University Radiocarbon Accelerator Unit.

Tom Higham: Prior to this method being developed in 1949, archeologists used what is called relative dating. They looked at archeological materials, pots predominantly, and they reason that pots of a similar type must be of a similar age and that other pots must be later and earlier. And this relative chronology is what archeologists used in the years before 1950 to work out the age, relatively speaking of archeological cultures and civilizations. So in 1949, when this method came along, it heralded and an immediate revolution and what we now call archeological science. And it gave archeologists the ability to independently calculate ages of materials that they found in archeological sites.

Walter Isaacson: Radiocarbon dating can be used to date items up to 50,000 years old. It’s been used to date everything from the dead sea scrolls to counterfeit bottles of allegedly well-aged scotch, but there’s one big challenge to carbon dating. If even a fraction of newer material is mixed in with a sample, it can throw off the measurements enormously, but using advanced new methods, Higham and his team are able to decontaminate archeological samples more thoroughly than ever before. His method has provided dramatically different readings that have changed the story of how we evolved as a species.

Tom Higham: One of the areas that I’m really interested in as a dating specialist is the period when the Neanderthals disappeared from the earth and when our modern human ancestors came out of Africa and populated the old world as we call it, the area of Eurasia, when the Neanderthals met modern humans. And dating science has been fundamentally important in understanding exactly what happened during this period. And unfortunately though, the ability of radiocarbon scientists to date this particular period has been really challenging because of this issue of contamination.

Walter Isaacson: But Higham has a secret weapon at his lab in Oxford, a $3 million particle accelerator. Higham used this particle accelerator to re-examine previously dated Neanderthal samples. And the data he’s gathered could not only change the way we understand this ancient human species, but also homosapiens as well.

Tom Higham: In the end, this enabled us to say something quite profound and important things about when the Neanderthals disappeared, instead of thinking that they disappeared in the 20s or 30s of thousands of years ago, all of our dates were earlier than 40,000 years ago. So we’re able to push back the dates at which we determined that Neanderthals disappeared. And at the same time, we also found that the dates we obtained for modern humans and their archeological remains and sites also went back further.

Walter Isaacson: It’s long been theorized that the primary reason Neanderthals went extinct is because our human ancestors killed them off. But Higham’s findings might indicate something different.

Tom Higham: And so it raises the possibility that perhaps instead of Neanderthal’s going extinct, it’s possible that the population may have been assimilated. There’s a lot of evidence from the genetics now that the demographics of Neanderthal populations was characterized by low population numbers and a low density. And so it’s possible, I think that these low numbers, it could simply have been that modern humans were present in larger numbers. And since we know that there’s an interbreeding, it’s I think a distinct possibility that there could have been an assimilation of that population into ours.

Walter Isaacson: While archeologists like Tom Higham are examining human history through the lens of microscopic isotopes, others are taking a wider view. Satellite technology has given archeology a perspective and sense of scale that would have been unimaginable to early Egyptologists.

Sarah Parcak: Think of when you’re on an airplane and you’re looking down from your seat.

Walter Isaacson: Sarah Parcak is a professor of anthropology at the University of Alabama, at Birmingham. And a pioneer in satellite archeology.

Sarah Parcak: And you’re able to see associations and connections between landscape features and houses. Well, satellite archeology kind of works in a similar way. Think of almost like a space-based cat scan where not only you’re looking down from above and you’re able to see these different patterns and relationships, but by using different parts of the light spectrum, you’re able to see what would otherwise be completely invisible varied features like walls, tombs, potential settlements, and even the foundations of pyramids because as they degrade over time, they affect the overlaying topography and vegetation in ways that we can’t see with our naked eye.

Walter Isaacson: Parcak believes satellite archeology gives archeologists the wider scope they need to see the big picture. It helps them see all the clues and connect the dots about how ancient civilizations were built and how their societies functioned.

Sarah Parcak: In archeology we say, it’s not what you find. It’s what you find out. So one site where I’ve done a lot of work is called Tanis, which everyone will know of course from Indiana Jones. Was Egypt’s capital around 1000 BC. So about 3000 years ago and using very high resolution satellite imagery, we were able to get an outline of almost the entire city from 3000 years ago. So for me, that the cool part wasn’t necessarily finding the city, but you could see houses that were different sizes and different shapes, and you could see how the architecture had evolved over time. So we could actually make inferences about sort of the economic situation at Tanis and the classes of people that lived there. So for me, that’s what’s exciting. Like you can use this technology to help bring to light stories about people that lived thousands of years ago.

Walter Isaacson: And while Parcak was scrutinizing images from satellites high in the Earth’s orbit, another archeologist was flying over the Cambodian jungle in a helicopter. A helicopter mounted with a powerful laser emitter that scans the ground and collects billions of points of data.

Walter Isaacson: Angkor is one of the world’s most astonishing archeological sites. For 500 years until it’s fall in the 15th century, Angkor was the capital of the Khmer empire in what is modern day Cambodia. It was a sprawling jungle metropolis that is thought to have supported a population of nearly a million people. The ruins you can see today, like the famed Temple of Angkor Wat are some of the most striking sites from the ancient world, but what about the once thriving city that surrounded them?

Damien Evans: The basic problem that we face with places like Angkor is that the famous monuments, whichever one is very familiar with and made of stone. And they’re very durable.

Walter Isaacson: Damien Evans is an archeologist from the French Institute of Asian Studies.

Damien Evans: But the cities of the people who built those monuments were made of non-durable materials like wood and thatch and this kind of thing. And these have just rotted away completely over the centuries, really, without a trace. However, what we’ve discovered in the last 20 or 30 years is that if you look closely at the surface of the landscape, you can see the ways in which they very subtly reshaped the surface of the landscape. So they’ve built mounds of Earth for instance, to stay above the floodwaters in the wet season and build their houses on top of. They’ve dug canals into the ground to manage water during the dry season, built reservoirs and this kind of thing.

Walter Isaacson: While these traces still remain, they’re difficult to see from the ground and the heavy jungle canopy makes satellite imagery like the kind used by Sarah Parcak practically useless. Enter LIDAR technology. LIDAR is a three-dimensional laser scanning technology used to map surfaces from afar. Over the past decade, Damien Evans has used LIDAR to map Angkor’s vast ancient sprawl. Flying over the jungle, the laser sends and receives millions of pulses every few seconds.

Damien Evans: Even if you have that quantity of points, two or three measurements per square meter, or of a vast area, sometimes thousands of square kilometers, you can use that information to reconstruct entire ancient cities that are obscured by forest. So we can see things like individual house mounds or stones even beneath dense jungle cover. So that’s why it’s a revolutionary technology for us.

Walter Isaacson: Ironically, this wide view approach to studying Angkor has led to a much more up close and intimate understanding of the lives of ordinary people who lived there for centuries.

Damien Evans: One of the things that’s always been frustrating about Angkor is the extent to which the traditional sources such as temples, statuary, inscriptions carved into stone and this kind of thing, focus on the lives of the elites and tell us really very, very little about the lives of everyday people. And what’s being revealed with new technologies like LIDAR is a story that’s much more complex and in many ways, much more interesting. So for instance, using LIDAR, we’ve been able to identify where the workers and the staff of the temples used to live. So we’ve been able to identify that the residential areas, the everyday neighborhoods of people.

Walter Isaacson: It’s even provided clues to the end of the Khmer empire. It had long been assumed that the Khmer fell to enemy armies, but now it’s suspected that the real enemy might’ve been bad urban planning.

Damien Evans: We found that they always quite profoundly transformed the landscape around them with hydraulic works with agricultural systems with reservoirs, canals. They often attempted to manage water sometimes in ways that were not very successful and perhaps contributed to the downfall of urban projects in particular areas. It’s been able to provide us windows, I guess, insights into the reasons for the rise and fall of particular places.

Walter Isaacson: With the ability to ingest enormous amounts of information from satellite, LIDAR and other forms of remote imaging. The next challenge for archeology is a very 21st century problem. How do you process this incredible quantity of new data?

Iris Kramer: I’m an archeologist and I turned to become a computer scientist.

Walter Isaacson: Iris Kramer is the founder of ArchEO a startup that uses machine learning to process archeological data.

Iris Kramer: And through my PhD in artificial intelligence, I developed an AI tool that uses deep learning to automatically detect archeological sites. So we use neural networks and we train them with areas, locations of previously known sites. And the network uses these images to learn the pattern that signifies a specific type of site.

Walter Isaacson: As she trains her networks, Kramer consults with archeologists who specialize in this specific region to weed out the inevitable false positives a software brings up.

Iris Kramer: You get your feedback from the expert, and then you retrain your model so that it works better. And then you just go through a loop of improving the model with the new data, so that eventually you hope it finds every site. And yeah, it won’t come back with false positives anymore.

Walter Isaacson: The network has gotten so good at finding sites that it surprises even her.

Iris Kramer: I’ve done a case study with the National Heritage Agency for Scotland. And we worked on an Island called Arran and initially I found 300 false positives there. And I asked for feedback from the experts to see how well, what my model was doing wrong. And they actually came back to me and said that 150 of those were previously unknown sites, which was really exciting and encouraging.

Walter Isaacson: Archeology was once the province of adventurous and arrogant treasure hunters looking to find exotic riches. But what was once an activity for wealthy dabblers and tomb raiders has evolved into a science of remarkable complexity. Satellites and LIDAR can allow us to see at a scope much wider than any human eye. And machine learning can crunch the huge amounts of data to help archeologists discover the unknown wonders that have been right under our nose.

Walter Isaacson: The story of our past continues to be told, it’s written in the carbon 14 we breathe and may one day allow our descendants to learn about how we lived. And by better understanding how ancient civilizations rose and fell. We might find answers to the problems that face us today. I’m Walter Isaacson, and you’ve been listening to Trailblazers, an original podcast by Dell Technologies. I’d love to hear what you think of the show. Leave us a review on Apple podcasts or wherever you’ve listened to today’s episode. Thanks for listening.