GUY RAZ, HOST:
Today on the show, ideas about the hidden things in our world and the people who find them...
SARAH PARCAK: That's right.
RAZ: ...For a living.
PARCAK: My name is Sarah Parcak, and I am an archaeologist.
RAZ: And as an archaeologist, Sarah Parcak searches for traces of past civilizations hidden beneath the earth for thousands of years. Do you think that every civilization eventually becomes buried and hidden?
PARCAK: Yeah, I think all civilizations do. I think there are also a lot of civilizations and cultures out there that we don't know about yet.
RAZ: Sarah has discovered an ancient amphitheater under the airport in Rome.
PARCAK: Like the equivalent of an ancient Cineplex.
RAZ: An unknown temple in Petra.
PARCAK: Could be a temple, not sure.
RAZ: And the lost city of Tanis in Egypt.
PARCAK: It was Egypt's capital for about 400 years.
RAZ: And how Sarah discovered these sites, not by digging but by building on a technique used by her grandfather.
PARCAK: My grandfather Harold Young was one of the pioneers of using aerial photography in forestry. And so by the time I got to college, I thought if grampy did this for forestry, I bet lots of people have done this for archaeology. It would be fun to see what he did, and I really - I feel like I was the first kid in the candy store. You know, virtually no one had used it before in Egypt.
RAZ: So after Sarah graduated, she started to experiment with a method that has now completely revolutionized archaeology, and as she explained on the TED stage, it's earned her a special title.
(SOUNDBITE OF TED TALK)
PARCAK: I'm a space archaeologist. Let me repeat that - I am a space archaeologist. This means that I use satellite images and process them using algorithms and look at subtle differences in the light spectrum that indicate buried things under the ground that I get to go excavate and survey. By the way, NASA has a space archaeology program, so it's a real job.
PARCAK: This is from a site south of Cairo. So let's have a look from space. You can't see anything. When we process the image using algorithms - think like a space-based CAT scan - this is what you see. This rectilinear form is an ancient tomb that is previously unknown and unexcavated, and you all are the first people to see it in thousands of years.
RAZ: So what does satellite imagery mean for all the hidden sites yet to be discovered? Sarah Parcak explains in just a moment. I'm Guy Raz, and on the show today, ideas about our hidden world. You're listening to the TED Radio Hour from NPR.
It's the TED Radio Hour from NPR. I'm Guy Raz. And on the show today, ideas about our hidden world. And just before the break, we were talking to space archaeologist Sarah Parcak about how satellite images can help her find places that have been hidden for centuries. OK, so how does it work? How do you use satellite images to find, you know, hidden places?
PARCAK: So satellite imagery allows us to do two things. It allows us to look at sites with a fresh pair of eyes, but why they're really valuable is that they record information in different parts of the light spectrum that we simply can't see with our human eyes. So imagine there's a stone wall somewhere in Italy that dates to the Roman period - so roughly 2,000 years ago - and you'd walk over a field. And you wouldn't see it.
PARCAK: Well, that stone wall which may be under a meter or so of earth, it affects the overlaying topography. So the roots going down - they couldn't go as deep because they'd be stopped by the stone wall. And so processing the satellite data, you can actually map out and see those changes...
PARCAK: ...And you start seeing straight lines. And those straight lines form structures which definitely aren't natural. So just as an example, we got a hold of new satellite imagery for most of the pyramid fields, and when I started processing it, it feels like cheating. You can see everything.
RAZ: How many sites have you guys found using pictures from satellites?
PARCAK: I'm at the point where I've lost count. It is in the many thousands, but I don't know anymore.
(SOUNDBITE OF TED TALK)
PARCAK: I believe we have barely scratched the surface in terms of what's left to discover. In the Egyptian Delta alone, we've excavated less than one-thousandth of 1 percent of the total volume of Egyptian sites. When you add to that the thousands of other sites my team and I have discovered, what we thought we knew pales in comparison to what we have left to discover. When you look at the incredible work that my colleagues are doing all around the world and what they're finding, I believe that there are millions of undiscovered archaeological sites left to find. Discovering them will do nothing less than unlock the full potential of our existence.
RAZ: I mean, what you're saying is we only know a tiny bit about our past. Is that true? I mean, is most of our history hidden?
PARCAK: I would say, yes, because history is always written by the winners. And, yeah, people are living in places where they've always lived for thousands of years. Look at places like Rome and Istanbul and Cairo. Those cities are layers upon layers upon layers of history. So I think we've taken a lot for granted about who we are and where we've come from. We think living in this very modern age with smartphones and the Internet and sort of this whole world of knowledge at our fingertips we know everything. But the more and more we delve into the past, the more we realize that we don't and that it has a lot of lessons to teach us for today.
RAZ: So if we start using, you know, satellite images - I mean, if this becomes the norm, is it just going to change everything we've known about our past?
PARCAK: Well, I think it already has. Huge discoveries have been made about new ancestors, human sexuality, human relationships, how we adapt to environmental change. I think what it's done is it's shown us for the first time the real scale of human occupation and really resilience.
(SOUNDBITE OF TED TALK)
PARCAK: I wish for us to discover the millions of unknown archaeological sites around the world by creating a 21st-century army of global explorers will find and protect the world's hidden heritage which contains clues to humankind's collective resilience and creativity. So how are we going to do this? We are going to build an online crowdsource, citizen science platform to allow anyone in the world to engage with discovering archaeological sites and protect them. By creating this platform, we will find the millions of places occupied by the billions of people that came before us. Acknowledging that the past is worth saving means so much more; it means that we're worth saving, too. And the greatest story ever told is the story of our shared human journey, but the only way that we're going to be able to write it is if we do it together. Thank you.
RAZ: Sarah Parcak - she's the winner, by the way, of this year's $1 million dollar TED Prize. It's given to someone who has a vision to change the world. Sarah's going to use the money to create her citizen archaeology platform to start identifying and protecting thousands, perhaps millions, of hidden sites around the world.
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