NOVA scienceNOW: January 9, 2007PBS Airdate: January 9, 2007 NEIL DEGRASSE TYSON (Host/Astrophysicist, American Museum of Natural History): On this episode of NOVA scienceNOW: imagine someday being able to take an elevator to space. Sound crazy? STEPHEN STEINER (Massachusetts Institute of Technology): I think it's crazy, but I still think it's possible. NEIL DEGRASSE TYSON: It will take some radically new materials. RAY BAUGHMAN (The University of Texas at Dallas): It's the dream of the future, but it's an achievable dream. MAN: Are you ready? NEIL DEGRASSE TYSON: And it will take the imagination of people like these weekend inventors... BRIAN TURNER (Kansas City Space Pirates): Come on. NEIL DEGRASSE TYSON: ...who battle it out to see whose Space Elevator prototype will out-climb the rest and take home $150,000 in prize money. If you win, that probably means more to you than just getting the money. BRIAN TURNER: I don't know. I think... NEIL DEGRASSE TYSON: And speaking of space, did you know that satellites are helping to uncover some of the hidden treasures of ancient cultures? TOM SEVER (Archaeologist, NASA): Now, from space, we can see where these sites are. NEIL DEGRASSE TYSON: It's a technology that can peel away the layers of the rainforest, to reveal structures more than a thousand years old. WILLIAM SATURNO (University of New Hampshire): This is revolutionary, and it changes the entire way we approach archeology in a tropical environment. NEIL DEGRASSE TYSON: And with this tool, it might finally be possible to solve one of archeology's most enduring mysteries: the rise and fall of the great Maya culture. BILL SATURNO: Fourteen hundred years, that's been there. NEIL DEGRASSE TYSON: Also you'll meet a very select group of people. WOMAN # 1: I'm 96. MAN # 1 : ...ninety-seven. WOMAN # 2: ...ninety-eight. MAN # 2: ...a hundred and one and a half years old. NEIL DEGRASSE TYSON: They've lived long and remarkably healthy lives, in spite of their less than stellar eating habits. WOMAN # 3: ...every day, French fries. WOMAN # 1: ...roast beef. NEIL DEGRASSE TYSON: What's their secret? WOMAN # 3: I really don't have any clue. NEIL DEGRASSE TYSON: But these researchers say they might. NIR BARZILAI (Albert Einstein College of Medicine of Yeshiva University): You know what? This is a longevity gene. NEIL DEGRASSE TYSON: And what they've learned could someday produce drugs that will extend life for all of us. DAVID SINCLAIR (Harvard University): We could see these in the next five to 10 years. WOMAN # 4: That would be wonderful. NEIL DEGRASSE TYSON: All that and more, on this episode of NOVA scienceNOW. Major funding for NOVA scienceNOW is provided by the National Science Foundation, where discoveries begin. And the Howard Hughes Medical Institute, serving society through biomedical research and science education: HHMI. Additional funding is provided by the Alfred P. Sloan Foundation, to portray the lives of men and women engaged in scientific and technological pursuit. And the George D. Smith Fund. Major funding for NOVA is also provided by the Corporation for Public Broadcasting, and by PBS viewers like you. Thank you. AGINGNEIL DEGRASSE TYSON: Hello, I'm Neil DeGrasse Tyson, your host for NOVA scienceNOW. First up: at one time or another, each of us wonders, "How long will I live? Seventy, 80, 90 years?" The average American lifespan is now about 78 years, but a few people live much longer, 100 years or more. They don't seem to age like the rest of us. Correspondent Chad Cohen met up with a few of them and the scientists who are trying to sort out why. MAN # 2: We don't feel old. We feel young. WOMAN # 5: We don't feel old. CHAD COHEN (Correspondent): There aren't many of them out there. WOMAN # 1: I'm 96. MAN # 1 : ...ninety-seven. WOMAN # 2: ...ninety-eight. CHAD COHEN: How old are you? MAN # 2: A hundred, one. CHAD COHEN: Only one in 10,000 of us, in fact, will defy all the odds and live the long, healthy lives that these folks have. What's the secret? WOMAN # 3: I really don't have any clue. WOMAN # 4: I don't have a secret. MAN # 2: You'll have to ask upstairs. CHAD COHEN: Well, down here, biologists are having a go, studying every aspect of these long-lived people to see if their elixir of life might be available to the rest of us. MAN # 2: Let's hope! CHAD COHEN: Nir Barzilai, of the Albert Einstein College of Medicine, in Bronx, New York, has worked with this genetically distinct population of Ashkenazi Jews for the last eight years, wondering, "What do they have that the rest of us don't?" NIR BARZILAI: They are born in the early 1900s; many children are dying in epidemics of childhood diseases. So they survive already that. And then they get to middle age and there are all the middle ages diseases. There is the cancer, and the cardiovascular, and they don't get touched by that. And then they have to survive getting to 100. It's an incredible journey against odds. WOMAN # 3: It wasn't really milk and honey, my life, but here I am. CHAD COHEN: But none of them have exactly been following doctor's orders. NIR BARZILAI: I would say the opposite. WOMAN # 3: ...every day, French fries. WOMAN # 1: ...roast beef. MAN # 1: You can drink, but no mixed drinks, just Scotch. NIR BARZILAI: There is no yogurt eater, there is no vegetarian. CHAD COHEN: Forty-six years of cigarette smoking? MAN # 2: Yah. CHAD COHEN: And you still 101 years old? MAN # 2: I'm still one-hundred-one-and-a-half years old. NIR BARZILAI: All the things that we tell our patients to do, they didn't do, and it didn't bother them, they got there anyhow. CHAD COHEN: Do you feel lucky that you've lived as long as you have? WOMAN # 3: Of course. CHAD COHEN: They did have help though, as Barzilai discovered. NIR BARZILAI: There is an unusual history of longevity in their family. WOMAN # 2: The youngest sister of my father was 98, and my mother was 92. MAN # 1: I still have an aunt, my mother's side of the family who's alive; she's a hundred and one. WOMAN # 4: This is a picture of my husband and this huge kiss. After that we got married. CHAD COHEN: Something very special was protecting them from the environment and their own excesses. WOMAN # 4: We have good genes. We owe it all to our mother and father. CHAD COHEN: And when the team peered into their blood, it became clear what it was. NIR BARZILAI: The initial thing that was striking is that many, many people in the study had very high HDL cholesterol. HDL cholesterol is the good cholesterol. CHAD COHEN: Good because it cleans up the bad cholesterol by schlepping the bad cholesterol away, so, the more the merrier. But something else was going on with the HDL cholesterol. We saw that they were amazingly large at our...with our centenarians. It seems the bigger the HDL, the better. Perhaps because bigger HDL hauls away more bad stuff than smaller HDL does. Sixty percent of the centenarians had these larger HDLs. NIR BARZILAI: So this became a major marker of exceptional longevity and also directed us to several of the genes that we tested. CHAD COHEN: Barzilai smeared our centenarians' DNA onto chips loaded with cholesterol genes. NIR BARZILAI: This chip contains 500,000 variations that humans can have on their DNA. CHAD COHEN: Barzilai found that three particular mutations in three different genes distinguished many of their DNA from the general population. And all those changes play a role in making HDL bigger and protecting against age-related disorders like diabetes and cardiovascular disease. NIR BARZILAI: So then we feel more comfortable in saying, "You know what? This is a longevity gene." CHAD COHEN: The idea of a small number of longevity genes flies in the face of scientific wisdom, which has long held that aging involves hundreds, even thousands of genes all running amok. But that's never sat well with MIT's Leonard Guarente, thanks to one bizarre, but confirmed, finding. Cut just about any organism's food supply by 30 to 40 percent, and it will live up to 50 to 60 percent longer. LEONARD GUARENTE (Massachusetts Institute of Technology): If aging is complicated, multi-factorial, so on and so forth, how could a simple dietary change make an organism live longer? CHAD COHEN: To find out, Guarente started simply, with a simple organism: baker's yeast, the stuff of beer and bread. In their brief lifespan —about two weeks—yeast cells typically divide a total of 20 times. Every once in a while though, a yeast lives longer than that, dividing, say, 25 or 30 times. Those are what Guarente looked for, the yeast equivalent of our centenarians. Well, it took them about eight years, but Guarente's group finally found that these long-lived yeast also have life-extending mutations in their DNA in a specific family of genes, called "sirtuins." Yep, genes have names too. Delete the most powerful of these genes, called "SIR2," from a yeast cell and it will die earlier. Add extra copies back in and it will live up to 50 percent longer. LEONARD GUARENTE: Okay, we know this is important for countering aging, but what does the gene do? CHAD COHEN: Ah, well sirtuins, as the scientists soon discovered, are part of an intricate stress response. When times are tough, they kick an organism into survival mode to beef up DNA repair or stop cells from dying. And it turns out, nothing sets these sirtuins into action like a shortage of food. LEONARD GUARENTE: And that's why our finding with SIR2, I thought, was an epiphany, because it gave a possible explanation for how a reduction in calories in the diet could be equated with a long life. CHAD COHEN: People have sirtuin genes too, although we don't know how important they are yet. But the more these scientists experiment in yeast, and then in worms and flies, the more they realize how vital this calorie-sirtuin connection is. David Sinclair, once a post-doc in Guarente's lab, now runs his own at Harvard Medical School. DAVID SINCLAIR: What my lab and others have found is that when you get rid of the SIR2 gene, the diet doesn't work anymore. CHAD COHEN: So put them on a calorie-restricted diet, they live longer. Take away this gene, put them on the same diet, they don't live longer? DAVID SINCLAIR: Exactly. CHAD COHEN: Amazing as that sounds, sirtuins aren't the only genes that do this. For more than a decade, Cynthia Kenyon of the University of California, San Francisco, has been making these microscopic worms, called "C. elegans" live far longer than believed wormly possible. CYNTHIA KENYON (University of California, San Francisco): You just change one gene and the whole animal is fine, it's incredible. CHAD COHEN: By damaging a single gene, this one's called daf-2, these worms live twice as long. Daf-2 helps makes insulin work. When it's mutated, you get less insulin, and that brings us back to calorie restriction because it has the same effect. CYNTHIA KENYON: You limit food intake, that leads to a decrease in the level of insulin, so that should lead to life span extension. CHAD COHEN: It turns out, low insulin levels kick on survival genes too, just like the sirtuins. So by damaging daf-2, the wormly life is longer. CYNTHIA KENYON: You can see why they call it elegans—they're very beautiful. CHAD COHEN: These squiggly squirmy guys are about four days old. But in two weeks... CYNTHIA KENYON: They look terrible. They're in the nursing home. They look like they're falling apart. Their heads are moving, barely, but that's it. And now, prepare yourself for something amazing. This is the mutant worm. We changed just one gene, the daf-2 gene, at that same age, and you can see it's moving around. It looks great. It's equivalent to looking at someone that's 90 and thinking that they're 45. CHAD COHEN: And the best part, when the equivalent genes were tweaked in flies and then in mice, their healthful properties were also preserved. CYNTHIA KENYON: These long-lived animals are resistant to a whole range of age-related diseases. The worms have muscle deterioration that happens later. The fruit flies are more resistant to heart failure. The mice are more resistant to cancer. This is a whole new way of thinking about disease, a whole new way. CHAD COHEN: But hold on a minute. If all of this research is so tied to cutting calories how do we explain these guys? WOMAN # 1: I always had breakfast; I always had lunch. MAN # 2: I eat whatever I like, and I do what I like. DAVID SINCLAIR: It could be that they have different variants of these longevity genes, allowing them to experience the effects of calorie restriction without really having to do the diet. CHAD COHEN: So what about the rest of us then, who may not be so blessed? Can we live longer by eating less? Well, it's not proven in people yet but the answer, to many scientists, is "probably"—if we eat a lot less, 30 to 40 percent less to be exact, which means the food someone like me might take in a day would shrink from about 2,500 calories to 1,500 calories. Hey, it's no fun, but people do it. DAVID SINCLAIR: I did try calorie restriction for about a week and gave up. It's not a pleasant way to exist. CHAD COHEN: Perhaps it was pangs of hunger that lead David Sinclair towards his next venture: finding drugs that offer the benefit of calorie restriction without the drastic diet. He's off to a good start. Sinclair found that resveratrol, the molecule that has been touted to make red wine healthful, stimulates the sirtuin genes and allows everything from yeast to worms to flies to live 30 to 40 percent longer. And it's looking good for mice. Barzilai, Guarente and Kenyon are also seeing their gene targets make their way into the pharmaceutical arena. DAVID SINCLAIR: I'm hoping that, within my lifetime, we'll see the benefits of this research. Being very optimistic, we could see these in the next five to 10 years. WOMAN # 4: That would be wonderful. CHAD COHEN: In the meantime, none of the scientists are exactly waiting around for this to happen. CYNTHIA KENYON: I eat a diet that is predicted to keep my insulin levels lower. LEONARD GUARENTE: I don't calorie restrict, but I don't gorge myself. DAVID SINCLAIR: I drink more red wine than I used to. NIR BARZILAI: My HDL is good, because I'm taking two different drugs to increase that. CHAD COHEN: Would you recommend living this long to everyone? MAN # 2: Why not? MAN # 1: Yes. WOMAN # 1: Of course. WOMAN # 2: Yeah. Life is wonderful. MAN # 2: When I am 110, I want to see you here again. CHAD COHEN: It's a date. MAN # 2: You shake hands with me? CHAD COHEN: I'll shake hands with you. It's a date. SPACE ELEVATORNEIL DEGRASSE TYSON: You're watching NOVA scienceNOW. Still to come on NOVA scienceNOW: WILLIAM SATURNO: When I shone my flashlight up on the wall, I saw the face of the Maya maize god there. I thought, "Well, I found this amazing thing, and I'm going to die right here, and someone is going to find it and me in 20 years." NEIL DEGRASSE TYSON: But first, did you ever think about taking a vacation in orbit? Sounds ridiculous, right? Well, when the Space Needle, here in Seattle, was built, in 1962—back at the dawn of the Space Age—lots of people thought they would soon be taking trips just like that. Of course, hasn't quite worked out that way. It costs about half a billion dollars just to take the space shuttle out for a spin. Kind of an expensive vacation isn't it? One, please. Thank you. But what if there was another way to get to space? And what if that way were as easy and as cheap as riding an elevator? Well, strange as it sounds, some people think this kind of trip might just be possible one day, thanks to something known as the Space Elevator, a 22,000-mile long cable that we could ride straight to outer space. STEPHEN STEINER: What we're talking about is building the biggest thing ever. NEIL DEGRASSE TYSON: And what enables this big idea is the discovery of something so small, you can't even see it with the naked eye: a new material called a "carbon nanotube." Fueled by the promise of these tiny tubes, people are already working to turn the Space Elevator into a reality. BRADLEY EDWARDS (Black Line Ascension): It's basically a fairly straightforward system once you get down to the nuts and bolts of it. First, launch a satellite to geosynchronous orbit, 22,000 miles above Earth. Then, lower a cable or ribbon and attach it to a platform at sea. Clamped to the ribbon, elevator cars, or climbers, could carry people and payloads up and down. Lasers, on the ground, would beam energy wirelessly to solar cells on the underside of the climber, powering electric motors for the 22,000-mile journey. NEIL DEGRASSE TYSON: Okay, I know what you must be thinking, "A 22,000-mile elevator ride? These people are nuts. Like, what would even hold it up?" Well, the idea is not quite as crazy as it sounds. STEPHEN STEINER: Imagine I have a yo-yo in my hand. As you spin the yo-yo around, the body of the yo-yo is thrust outward and the string connecting you to the yo-yo is held taut. Well, this is the same principle that would keep the Space Elevator up. We're basically making a planet-sized yo-yo. NEIL DEGRASSE TYSON: A Space Elevator could be safer and cheaper than rockets, giving routine access to the solar system. Bringing this far-out idea down to earth, NASA recently funded a competition, in New Mexico, to build and race Space Elevator prototypes. It was held at the X Prize Cup, a carnival of cutting-edge space technology. In the tradition of competitions that stretch farther back than Charles Lindbergh's transatlantic flight, the aim is to inspire new advances in technology. This year, teams of students and weekend inventors are vying for the $150,000 in prizes in the Space Elevator contest. MATTHEW ABRAMS (StarClimber Space Elevator Team): I heard about this competition, and I thought, "Wow! You don't have to have a billion dollars and an aerospace company to do this." BRIAN TURNER: We're definitely at the cutting edge. You're going to see stuff go wrong today. NEIL DEGRASSE TYSON: The racetrack is a 50-meter ribbon suspended from a crane. Teams had to design and build climbers, then race them to the top of the ribbon. In place of the laser that might otherwise power a real Space Elevator, they could use only energy from the sun or beamed from the ground. The best time wins, as long as you go faster than a meter per second. One of the first to try their luck is a high school team from Germany with an elevator sporting an intimidating solar panel and name. JOERN LUTAT (Max Born College): Turbocrawler. NEIL DEGRASSE TYSON: Turbocrawler. All right! That sounds mean. Sounds, sounds like it's going to win. But as Turbocrawler is about to take off, the wind picks up, Turbocrawler gets out of hand, and the Germans are grounded, at least for the time being. Julie Bellerose and her team from the University of Michigan are next to jump on the ribbon. ROGER GILBERTSON (The Spaceward Foundation): The whole big idea behind doing this is to get engineers in school to start working on this. At the end of this event there are kids here who are going to know more about Space Elevator technology than NASA scientists are. NEIL DEGRASSE TYSON: Julie's climber is powered by a dozen spotlights that each have to track the solar panels all the way up the ribbon. JULIE BELLEROSE (University of Michigan): Light on! NEIL DEGRASSE TYSON: The climber gets off to a good start. But the higher it rises, the harder it becomes to hit the solar panels with the spotlights, to keep it going. JULIE BELLEROSE: ...Number 4. NEIL DEGRASSE TYSON: After about 6 minutes of stopping and starting, the climber reaches the top. JULIE BELLEROSE: We didn't make it in the time required, but I think one of the goals is to make it to the top, so we're very happy. NEIL DEGRASSE TYSON: NASA's prize money is safe, at least until the contest resumes the next day. Now, if you think the whole idea of an elevator to space sounds like science fiction, you're right. It was popularized in the late 1970s in a sci-fi novel called The Fountains of Paradise by Arthur C. Clarke. ARTHUR CLARKE: (Author, The Fountains of Paradise): At last we can build a space elevator. And then we will have a stairway to heaven, a bridge to the stars. NEIL DEGRASSE TYSON: But as long as people have dreamed of building that bridge to the stars, no material existed to make a cable that's strong enough. That is, until we found that one of nature's most common atoms, carbon, was leading a secret life. STEPHEN STEINER: I wouldn't say carbon is promiscuous. I would just say it's very open-minded. NEIL DEGRASSE TYSON: Carbon atoms just love to form extremely strong chemical bonds with one another. We knew they could be arranged in a lattice to form diamond or in sheets to form graphite. But until recently, we had no idea they could also form tiny spheres called "buckyballs" and tiny tubes called "carbon nanotubes." Much stronger and lighter than steel, and able to conduct electricity, these cylinders of pure carbon have been called a wonder material, a new building block that might be used in everything from electronics to airplanes. But as a Space Elevator cable, carbon nanotubes have some big problems: the longest ones ever made are only a few centimeters. And joining them together end to end, one at a time, is simply not practical. So how would we ever use these tiny tubes to make a cable that's 22,000 miles long? Deep in the heart of Texas, scientists are taking a different approach to assembling carbon nanotubes. RAY BAUGHMAN: It's the dream of the future, but it's an achievable dream. NEIL DEGRASSE TYSON: To make a batch of carbon nanotubes, bake a silicon plate coated with iron particles, at 1,300 degrees Fahrenheit, in a special oven. Then, add a dash of acetylene, a gas that contains carbon. When acetylene comes in contact with the iron, it releases its carbon atoms, which assemble—as seen here—into nanotubes. When the plate comes out, it's coated with a black soot that contains trillions of carbon nanotubes, all aligned vertically in what Ray Baughman calls a "forest." RAY BAUGHMAN: Think of a bamboo forest. NEIL DEGRASSE TYSON: But unlike a real bamboo forest, the trees in a nanotube forest tend to stick together, thanks to a faint force operating at the nanoscale called the Van der Waals force. It's sort of like magnetism. RAY BAUGHMAN: So, when you pull one nanotube out, you pull its neighbors. And then they pull out their neighbors. NEIL DEGRASSE TYSON: Pulling a whole row of nanotubes from the forest on the left, they can draw out a ribbon of pure carbon nanotubes, held together by nothing but the Van der Waals force. This ribbon is less than one-thousandth the thickness of a human hair, and it's stronger than steel. But can nanotube ribbons ever be made strong enough for a Space Elevator cable? RAY BAUGHMAN: That is an unresolved question, but in science and technology, I've learned to never use the word "never." NEIL DEGRASSE TYSON: Back in New Mexico, the mood is more optimistic as the second day of the Space Elevator competition gets underway. Among those hoping to claim NASA's $150,000 prize is Brian Turner, captain of a truly homegrown team, the Kansas City Space Pirates. BRIAN TURNER: I've got my dad, my step-dad, my mom, my uncle...great-uncle Max. NEIL DEGRASSE TYSON: Uncle Max. I'm Neil Tyson. MAX: Neil. NEIL DEGRASSE TYSON: All right. You're one of the family affair. If you win, that probably means more to you than just getting the money. MAX: Oh, yeah. BRIAN TURNER: I don't know. I think... NEIL DEGRASSE TYSON: Hoping to make their elevator sail up the ribbon, the Space Pirates pull out their secret weapon: 15 mirrors, each the size of a twin bed. BRIAN TURNER: One person on each mirror. NEIL DEGRASSE TYSON: Beaming sunlight to your collecting mirror? BRIAN TURNER: Right. NEIL DEGRASSE TYSON: To the solar panel? BRIAN TURNER: Right. NEIL DEGRASSE TYSON: Giving the energy to climb. BRIAN TURNER: Right. ANNOUNCER: Are you ready? All right, here we go. NEIL DEGRASSE TYSON: Halfway up the ribbon, the wind kicks in again. BRIAN TURNER: Got to get up there. I'm going to go look at it this way. NEIL DEGRASSE TYSON: Bouncing in the breeze, the parabolic mirror can't stay focused on the solar cells, and the Pirates' elevator grinds to a halt. BRIAN TURNER: Come on. Come on. If the wind hadn't been bucking, I might have been better off. But I can't believe I didn't make it to the top. I figured I could fight my way up there. NEIL DEGRASSE TYSON: Next up, and favored to win, is the University of Saskatchewan Space Design Team, or USST, for short. TEAM MEMBER: Go time, right? It's go time. NEIL DEGRASSE TYSON: Their secret weapon: a stationary mirror to reflect a spotlight straight up the ribbon to the solar array. TEAM MEMBER: Phase one. NEIL DEGRASSE TYSON: It looks like they make it to the top in record time, fast enough to claim the $150,000 prize. So did they win? BEN SHELEF (The Spaceward Foundation): We have to have a little discussion about that. NEIL DEGRASSE TYSON: Before the prize money can be awarded, the remaining teams get one last chance. The German Turbocrawler crawls all the way to the top, but it's no prize winner. And late in the day, a team of high school students from California posts an impressive two-minute run. EVAN JOHNSON: It's pretty good that we got 2:02. JEFFREY GRATTAN: It's going on our resumes. NEIL DEGRASSE TYSON: But in the end, the prize money went unclaimed, because it turns out Saskatchewan fell just short of the minimum speed of one meter per second. CLAYTON RUSZKOWSKI (University of Saskatchewan Space Design Team): Next year, most of us are coming back, and we're going to just totally take it up two notches and just go all out. NEIL DEGRASSE TYSON: But will we ever take a ride in a real Space Elevator? STEPHEN STEINER: I think it's crazy, but I still think it's possible. And I think it's something that, if we can do it, we should do it. NEIL DEGRASSE TYSON: Well, one thing's for sure, we have a long way to go before that happens. But, who knows? Perhaps someday technology will catch up with our imaginations and take the Space Elevator out of the realm of science fiction once and for all. Once you get into space, there's lots of interesting stuff you can do there. High above Earth's atmosphere, you can get a clearer view into the cosmos, learn about distant stars and galaxies. But did you know you could also head out here to do archeology? It turns out there are secrets about our ancient past, hidden down on Earth that are best revealed from space. Correspondent Peter Standring uncovers the story. MAYAWILLIAM SATURNO: It's difficult to convey what this place would have been like when it was inhabited. As you look out around, none of this rainforest was here at that time. Instead, you were looking at this bustling metropolis of 100,000 people gathered here: the sounds, the smells, smoke rising up from the houses, the thousands of houses that littered the countryside. PETER STANDRING (Correspondent): For 1,200 years, the Maya civilization dominated Central America, and here, in the jungles of northern Guatemala, the great city of Tikal was one of the wonders of the New World, with centuries of art, architecture and astronomy while Europe was still in the dark ages. Limited by poor farmland and a yearly drought, the Maya somehow supported a population that numbered in the millions. But just at the peak of Maya power, their world suddenly fell apart, about 12 centuries ago. How such a civilization could collapse so quickly remains one of the great unsolved mysteries of archeology. Tikal lasted for 1,000 years, but somehow it reached a tipping point where it could no longer support its population. And so, within a generation or two, 80 percent of the people who lived here disappeared. WILLIAM SATURNO: Within about 40 years of this city's height, we see this place almost entirely abandoned. And trees were beginning to grow on the surfaces where kings once walked. PETER STANDRING: For archeologist Bill Saturno, understanding the end of the Maya civilization has always involved finding evidence of how it began, 3,000 years ago. In the spring of 2001, he and a group of local guides were hot on the trail of three rare carved monuments; so eager to find them, they nearly met their own end. WILLIAM SATURNO: The rumor was that this site was only one day's journey away. And so we planned a journey of a day, and we brought food and water for one day. And it turned out that the journey was three days. Now, how one gets two days into the woods without food or water is that they need to make a series of bad decisions. In fact, they need to be committed to making bad decisions again and again and again, because there are opportunities to turn back, and you simply don't. PETER STANDRING: But turning back would have caused Saturno to miss the discovery that changed his life, as his group wandered into the ruins of a small Maya city in an area the locals called San Bartolo. There, among the buried Maya buildings was an 80-foot pyramid with a deep trench that looters had cut into its side. Saturno had stumbled on an ancient temple, but in his dehydrated state, it simply meant relief from the hot sun and 100-degree heat. WILLIAM SATURNO: I thought to myself, "It's got to be much cooler inside there, and if I just crawl into that, I can sit down, it'll be shady and, and at least I won't feel as bad as I feel now." And I walked in past where the light entered, and I sat down, just in the darkness. And when I shone my flashlight up on the wall, I saw the face of the Maya maize god there. PETER STANDRING: Despite his exhaustion, Saturno still knew he was looking at an incredible find. WILLIAM SATURNO: This was clearly the discovery of a lifetime, but pity my life will be so short. I thought that when I sort of laid down to rest, that I was lying down to rest for the final time. PETER STANDRING: As the expedition's most experienced guide, Anatolio Lopez knew the situation was dire. ANATOLIO LOPEZ (Guide, Proyecto San Bartolo): And then I went out to see if I could find something that would ease the thirst. So I found a flowering plant they call Pinuela. PETER STANDRING: The fruit of the Pinuela measures only a couple of inches, but its moisture saved Saturno's life and got the group moving again, revived enough to walk out of the rainforest alive. Bill Saturno had discovered the oldest Maya paintings ever found, depicting religion and government as far back as 100 B.C. WILLIAM SATURNO: The murals at San Bartolo are really our earliest example of this relationship between god and kings, spelled out in this wondrous work of art. And these are the earliest hieroglyphic texts we have in the Maya lowlands. They predate the text that we can read by five centuries. PETER STANDRING: Can you think of an analogy, in terms of the impact, something like this has? WILLIAM SATURNO: Well, I mean, essentially, this would be like finding sort of the story of Christ, but written at the time of Christ. PETER STANDRING: News of Saturno's discovery quickly spread to Maya experts everywhere. TOM SEVER: Well, we had heard that Bill had come across something major, that he had...what ultimately became the discovery of the murals. PETER STANDRING: Tom Sever is the only archeologist on the NASA payroll using the space agency's aircraft and satellites to survey ancient sites on the ground. It's a technology called "remote sensing," and it can reveal hidden details in the landscape below. From space, satellites record invisible wavelengths like infrared. What we perceive as heat, satellite cameras turn into light. TOM SEVER: It can see beyond the range of our vision. It can detect features that we can't see. And through the use of computers, we can record that invisible information and bring it back into visible light. PETER STANDRING: Using remote sensing, Sever proved the Maya used innovative agriculture on land poorly suited to grow crops. Satellite photography peered through layers of the modern rainforest to reveal intense cultivation, connected by a pattern of ancient roadways. TOM SEVER: From the perspective of space, we can look down, and we can see how the Maya were able to feed this intense population. We could see the Maya roadways, causeways. We could find their water reservoirs, water storage areas and canal systems. PETER STANDRING: The images charted areas right next to Bill Saturno's excavation at San Bartolo. And when Tom Sever sent satellite maps to help his colleague, Saturno immediately noticed one very curious detail in the satellite imagery. WILLIAM SATURNO: In looking at the satellite image, it immediately became clear to me that the forest in San Bartolo was of a lighter color than the forest outside of San Bartolo. And so, in looking farther afield, looking across that image, you could see other areas that shared that same color. And, of course, the thought is, "Well I wonder if those are archaeological sites too." PETER STANDRING: So with a GPS locator in his hand, Saturno plotted a course to the other brightly colored spots on his NASA map, scattered all over the landscape. WILLIAM SATURNO: And as you get closer to them, you're saying to yourself, "In 10 meters, we should be walking into an archaeological site. Now, if this works, we have five meters to go until we find architecture. And then you walk that five meters and sure enough, you walk up onto a Mayan building. PETER STANDRING: Buried under a thousand years of vegetation was the unmistakable shape of a Maya pyramid, precisely where the satellite image had predicted it would be. Saturno found three Maya sites around San Bartolo in the areas where the maps showed a change in the color of the vegetation. He reported back to Tom Sever, it seemed to work every time. TOM SEVER: We were skeptical at first. We had no doubt that this was working sometimes, but that it was working accurately all the time, we just couldn't buy into that. So as we started looking at the imagery, we started wondering, "What's causing that in the vegetation?" PETER STANDRING: Sever theorized that, over the centuries, the limestone that the Maya used as building material had seeped into the soil, changing the vegetation growing on Maya sites, but nowhere else. The chlorophyll in plants glows brightly in infrared, and satellite cameras picked up that subtle difference. TOM SEVER: If this was true, this is big news. I've been working on Mayan archaeology for a long time, and we've had great success, but this would be the crowning achievement, if we were able to map where all the Maya sites were. PETER STANDRING: There was only one way to find out. Sever came down to Guatemala to join Saturno, to see for himself. The road to San Bartolo runs 50 kilometers through the seasonal wetlands called "the Bajos." WILLIAM SATURNO: Once the rains start, the Bajos become impassible. PETER STANDRING: They need to push beyond San Bartolo to remote locations never explored by archeologists. But it's already becoming a very long day. WILLIAM SATURNO: We spent more than two hours in four vehicles, with winches and people pushing, and we achieved less than a kilometer. PETER STANDRING: After several days, and on drier ground, the archeologists use only the NASA maps to thread their way deep into the rainforest, towards a bright site on the satellite image: the brighter the color, the more Maya limestone, the bigger the potential site. But would the theory actually work? TOM SEVER: It was just mind-blowing. We're in this dense vegetation, incredibly hot, 119 degrees. You see it? WILLIAM SATURNO: We should be right there, but, we're in it. TOM SEVER: We're close. WILLIAM SATURNO: And we get about 10 meters away from where the site is supposed to be, but I don't see an archaeological site. I thought, "Oh," You know? "Great." TOM SEVER: No indicator, and, my thought was, again, this, you know, "Why am I out here? Why did I fall for this?" WILLIAM SATURNO: "So this is the time it doesn't work. They're really going to think I'm nuts. I bring them all the way down here, we're going to go out and find this place, Ten meters, nothing." TOM SEVER: And then, five meters, we'd move forward, and there's a giant temple, right on target. WILLIAM SATURNO: Fourteen hundred years, that's been here. TOM SEVER: We did this for many days. We saw many sites, with incredible accuracy, and I became absolutely convinced. WILLIAM SATURNO: Pretty impressive structures—two stories, from the first floor to the second floor. PETER STANDRING: The satellite imagery was flawless. The huge temple was exactly where the map coordinates predicted it would be. WILLIAM SATURNO: This is a pretty impressive room. These walls are a good two meters high. It's a great vault. TOM SEVER: The paint hasn't faded too much. WILLIAM SATURNO: You can see it's really thin plaster that they're using. It's in great shape, but you can tell it's a resource that's really at its end. PETER STANDRING: The site at San Bartolo has now become a pilgrimage for shamans of the Maya religion, descendants of the ancient civilization that once ruled here. It's pretty incredible that satellites miles and miles and miles up in space are seeing things that you and I can't see here. WILLIAM SATURNO: This is revolutionary, and it changes the entire way that we approach archaeology in a tropical environment. PETER STANDRING: Thanks to the collaboration of archeology and space technology, scientists are beginning to learn how the Maya conquered this harsh landscape as no modern civilization ever has, and how they, quite suddenly, lost control of it. TOM SEVER: Now, from space, we can see where these sites are. And now we have enough material to understand the rates of deforestation that might have taken place here—as a result from the construction of all of these buildings and temples and roadways—and ultimately contributed to their own drought, their own destruction. WILLIAM SATURNO: All of a sudden, for the first time, we're able to look at the big picture and understand the extent to which the Maya expanded these cities. When you think about how many sites are out there, just in the Mayan lowlands...And we can see how many there are in these satellite images. Think about how many San Bartolos are out there waiting to be discovered. PROFILE: BONNIE BASSLERNEIL DEGRASSE TYSON: Some people have a special way with other living things, They seem to understand them, even relate to them. You've heard of horse whisperers and maybe even dog whisperers. Well, in this episode's profile, here's a scientist who is tuned in to some creatures I guarantee you have never talked to. In fact, you can't even see them. She's been called the "Bacteria Whisperer." But with a whisper is never how Bonnie Bassler starts her day. This MacArthur Fellow, and prestigious Howard Hughes Medical investigator, and member of the National Academy of Sciences, starts each weekday in aerobics class—as the teacher, of course. BONNIE BASSLER (Princeton University): I have been teaching aerobics for 23 years, more than half of my life. And everybody thinks I'm so committed to this, and I'm so disciplined. And it's a big scam, because I would never go, if I wasn't the teacher. NEIL DEGRASSE TYSON: But Bonnie is a teacher to the core, in aerobics and in molecular biology at Princeton... BONNIE BASSLER: Who wants to talk to me about science? NEIL DEGRASSE TYSON: ...where she also wants to see some sweat. BONNIE BASSLER: Five or ten minutes, get some science! If you want me to do it for you... STUDENT: Yeah? BONNIE BASSLER: ...I won't because it wouldn't kill you to learn a little genetics. Come on, you guys! NEIL DEGRASSE TYSON: In fact, ask Bonnie about bacteria, and she just can't help teaching. BONNIE BASSLER: Bacteria are single-celled organisms. Bacteria are the model organisms for everything that we know in higher organisms. There are 10 times more bacterial cells in you or on you than human cells. NEIL DEGRASSE TYSON: Bonnie and her lab work on how bacteria talk to each other. That's right: bacteria talking. It's a process called quorum sensing, and Bonnie's lab has been leading the way in understanding exactly how it works. NED WINGREEN (Princeton University): She's really the one who's shown that this is something, that this is something that all these bacteria are doing all the time. And if we want to understand them, we have to understand quorum sensing. BONNIE BASSLER: So I grew up some bacteria for you to see, and I want to show you my favorite part, so you have to come with me into this room. NEIL DEGRASSE TYSON: Bonnie has spent years studying vibrio harveyi, marine bacteria that are harmless to humans and, triggered by quorum sensing, glow in the dark. By themselves, or in small numbers, these bacteria don't glow. They wait until they've assembled a quorum, that is, as they divide and their numbers increase, they each release a signaling molecule. BONNIE BASSLER: We call autoinducers but you can think of like hormones. NEIL DEGRASSE TYSON: That is made by a gene in each of the neighboring vibrio harveyi as a way of announcing, "Hey, I'm here, too." BONNIE BASSLER: They have these detectors on their membranes that you can think of like little locks and keys. And the molecule goes in, and once they feel that, then they know there's neighbors around. NEIL DEGRASSE TYSON: And when enough of these little guys have gotten together to form a critical mass, they all light up at the same time. BONNIE BASSLER: So now, if I turn the lights off in the room, you're going to see them make this beautiful bioluminescence. NED WINGREEN: One bacteria isn't able to make an impact by itself, but if there are a lot of them, they can work together. So quorum sensing is the way that they know, "Are there enough of us to undertake one of these group activities?" BONNIE BASSLER: It's incorrect to think of bacteria as these asocial, single cells. They are individual cells, but they act in communities, exactly the way people do. NEIL DEGRASSE TYSON: Bonnie was doing her post-doctoral work, when she found the genes that allow for communication in vibrio harveyi. And scientists from around the world yawned, because Bonnie's discovery was only in this species of marine bacteria, and not in one that's dangerous to humans. BONNIE BASSLER: There's these few bacteria that were models, e-coli and salmonella, and if you didn't work on the models, then you worked on a pathogen, something that was important for human health. And so this quorum sensing, which—we didn't even call it this back then, because it was in this luminous bacteria that doesn't even hurt a fish—it was never going to be relevant for understanding even bacteria or higher organisms. NEIL DEGRASSE TYSON: But Bonnie believed otherwise. She thought her bacteria could tell her more about how all bacteria communicate, so she applied for a job to continue her work in quorum sensing. BONNIE BASSLER: Oh, I applied to a lot of places for a job. I don't know, 20 or 30 or 40. And I got two interviews and one job. NEIL DEGRASSE TYSON: Yeah, but that one job was at Princeton University. TOM SILHAVY (Princeton University): I was chair of the committee that hired Bonnie Bassler. I know people at other places...I don't want to name names, but one of them said, "Why did you hire her?" NEIL DEGRASSE TYSON: Let's just say she did okay by landing at Princeton, and Princeton's belief in Bonnie had a huge payoff: her lab eventually discovered a second molecule used by her luminescent bacteria to communicate. And this second molecule was nearly universal. BONNIE BASSLER: We found it, originally, of course, in vibrio harveyi. But then we could show that hundreds of bacteria made and used this molecule and that it was in every bacterium anybody's heard about. NEIL DEGRASSE TYSON: That means that even dangerous bacteria communicate by quorum sensing. Deadly pathogens turn deadly the same way that Bonnie's bacteria turn on their light. Bonnie showed that there were two types of molecules that bacteria use for communication, that bacteria are bilingual. One type of molecule is used for communicating within their own species, and the other type, discovered by Bonnie, is used to talk to every species around them. BONNIE BASSLER: Bacteria live in unbelievable mixtures of hundreds or thousands of species. Like on your teeth. There are 600 species of bacteria on your teeth every morning. And so, in order to get these beautiful communities, where they're working together and doing all these things, they have to know who their neighbors are. NEIL DEGRASSE TYSON: And some of those neighbors are not friendly. Using the molecule found by Bonnie's lab, bacteria know if they're surrounded by friend or foe, or when it's safe to light up or attack. If they don't have superior numbers, they won't act. Sometimes they team up across species, but mostly, it's a tiny jungle out there. BONNIE BASSLER: There's eavesdropping and free-riding and cheating. And one guy's out there making a molecule, and the guy next to him eats it so that the molecule disappears. NED WINGREEN: My gosh, these bacteria talking to each other across species. And that's something that had really not been an accepted idea. This was sort of just a crazy idea. TOM SILHAVY: What Bonnie did to show that different species of bacteria could talk to each other really changes the landscape. And when that was realized by the rest of the scientific community, Bonnie's career took off like a rocket. NEIL DEGRASSE TYSON: But Bonnie was not launched by a scientific family. BONNIE BASSLER: We never talked about science. My mom was a stay-at-home mom, my dad was a businessman, and my brother's a businessman, and my sister's in politics, right? So we're just all over the map. NEIL DEGRASSE TYSON: She moved around a lot as a girl, but was always kept grounded by her mother. BONNIE BASSLER: My mom was the linchpin of this family. And I remember her saying things to me like, "You know, when I went to college, you could be a teacher or a nurse. Those were your two choices, as a woman," she goes, "but Bonnie, you could be anything you want." NEIL DEGRASSE TYSON: Bonnie's mother died when Bonnie was just a junior in college. BONNIE BASSLER: I remember her telling me, when she was sick, that she would take all the steps the same. So I think she got payoffs, even though she didn't get the ones that like, you know, the world sees as the payoffs. Because these are like very...they're tangible, acceptable things, you know? The MacArthur, the National Academy, Howard Hughes, those are things that you can write in a Christmas card, right? And she just would've written other things. NEIL DEGRASSE TYSON: Big things like Bonnie marrying actor Todd Reichart; little things like mercilessly beating her husband and colleagues at board games. Biologist Eric Wieschaus won a Nobel prize, but this night, lost to Bonnie. BONNIE BASSLER: Yeah! TOM SILHAVY: I've taken enormous pride in what she's accomplished. I would argue that our committee just did one hell of a fantastic job. NEIL DEGRASSE TYSON: But as Bonnie sees it, her work has only just begun. Quorum sensing is helping to shape a path to new drugs. Antibiotics currently work by killing bacteria, and more and more bacteria have grown resistant to these drugs. By using quorum sensing, it may become possible to disrupt a pathogen's communication, to neutralize it. For the foreseeable future, that's where Bonnie and her team will be putting their sweat. BONNIE BASSLER: I want to make a drug. I want the science to be more than imaginary, where I think, "We're learning these fundamental principles, blah, blah, blah, blah, blah." I think we are doing that, but I want to do something really practical. I want to actually, in my lifetime, help people. NEIL DEGRASSE TYSON: And now for some final thoughts on aging in the cosmos. It was not until a century ago that we began to apply the methods and tools of astrophysics to learn just how old the Sun and the rest of the stars might be, which leads to questions such as, "Do all stars live to the same age? Or do they reveal a range of lifetimes? And are some immortal?" When we carefully study their properties, such as mass and composition, combined with some basic laws of physics, we learn that, just like us, not all stars will die at the same age. Some, the high-mass ones, live life in the fast lane. They run through their fuel supply at prodigious rates, lasting a mere million years. Our Sun is just an average star, unremarkable in almost every way. It's been shining steadily for about half of its 10-billion-year life expectancy. And other stars, the low-mass ones, are so efficient and so slow in the rate they make energy that they will live for trillions of years, a thousand times the current age of the universe. We know all this because the galaxy has a hundred billion stars, enough to catch some being born, to catch most living through their middle age, and still others in the act of dying. Of course, if we live to a hundred, or even a thousand, that's still a mere moment in cosmic time, insufficient, by far, to watch the Sun, or any other star, live out their entire lives, even as they watch us live out ours. And that is the cosmic perspective. And now we'd like to hear your perspective on this episode of NOVA scienceNOW. Log on to our Web site and tell us what you think. You can watch any of these stories again, listen to podcasts, hear from experts and much more. Find us at pbs.org. That's our show. We'll see you next time. Educators and other educational institutions can order this or other NOVA programs, for $19.95 plus shipping and handling. Call WGBH Boston Video at 1-800-255-9424. NOVA is a production of WGBH Boston. Major funding for NOVA scienceNOW is provided by the National Science Foundation, where discoveries begin. And the Howard Hughes Medical Institute, serving society through biomedical research and science education: HHMI. Additional funding is provided by the Alfred P. Sloan Foundation, to portray the lives of men and women engaged in scientific and technological pursuit. And the George D. Smith Fund. Major funding for NOVA is also provided by the Corporation for Public Broadcasting, and by PBS viewers like you. Thank you. PRODUCTION CREDITSNOVA scienceNOW: January 9, 2007 Aging
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