A small NASA spacecraft embarks on a two-year mission this weekend to give scientists their first view of the happenings at the edge of the solar system.
NASA hopes its new Ibex probe will help explain why the sun's protective heliosphere is shrinking.
The Ibex probe, short for Interstellar Boundary Explorer, will study a chaotic region in space where the solar wind from the sun clashes with cold gases from interstellar space.
The solar wind, a stream of charged particles spewing from the sun at 1 million miles (1.6 million kilometers) per hour, carves out a protective bubble around the solar system. This bubble known as the heliosphere shields against most dangerous cosmic radiation that would otherwise interfere with human spaceflight.
Scientists recently discovered that the solar wind pressure is at its weakest level in 50 years, although the exact reason remains a mystery. Ibex could help confirm whether the heliosphere is shrinking.
Observations from Ibex should help researchers in "unlocking the secrets of this important interaction between the sun and the galaxy," said David McComas of the Southwest Research Institute in San Antonio. He is chief scientist for the $165 million mission.
Ibex, the size of a bus tire, will be launched aboard a Pegasus rocket that will be dropped from an aircraft over a Pacific atoll on Sunday.
The rocket will lift Ibex 130 miles (209 kilometers) above Earth and put it into orbit. The spacecraft will then fire its solid rocket motor to loft itself even higher, eventually to 200,000 miles (321,853 kilometers) above Earth.
Ibex will build on the discoveries of the long-running twin Voyager spacecraft launched in 1977 to explore the outer planets. The deep-space, manmade probes have since sailed past the outer planets and are headed out of the solar system.
Unlike the Voyager craft, Ibex will not barrel through space, but instead will do its job from high-Earth orbit. The probe carries two sensors that will collect information about the solar wind's mass and energy from all directions.
Buried History--A new remote sensing technology has peeled away mud and earth layers near the Cahuachi desert in Peru to reveal an ancient adobe pyramid, Italian researchers announced on Friday at a satellite imagery conference in Rome. In this satellite image, the white arrows show the buried pyramid and the black arrows other structures which have yet to be investigated
Oct. 3, 2008 -- A new remote sensing technology has peeled away layers of mud and rock near Peru 's Cahuachi desert to reveal an ancient adobe pyramid, Italian researchers announced on Friday at a satellite imagery conference in Rome .
Nicola Masini and Rosa Lasaponara of Italy 's National Research Council (CNR) discovered the pyramid by analyzing images from the satellite Quickbird, which they used to penetrate the Peruvian soil.
The researchers investigated a test area along the river Nazca. Covered by plants and grass, it was about a mile away from Cahuachi's archaeological site, which contains the remains of what is believed to be the world's biggest mud city.
Via Quickbird, Masini and colleagues collected hi-resolution infrared and multispectral images. After the researchers optimized the images with special algorithms, the result was a detailed visualization of a pyramid extending over a 9,000-square-meter area.
The discovery doesn't come as a surprise to archaeologists, since some 40 mounds at Cahuachi are believed to contain the remains of important structures.
"We know that many buildings are still buried under Cahuachi's sands, but until now, it was almost impossible to exactly locate them and detect their shape from an aerial view," Masini told Discovery News. "The biggest problem was the very low contrast between adobe, which is sun-dried earth, and the background subsoil."
Cahuachi is the best-known site of the Nazca civilization, which flourished in Peru between the first century B.C. and the fifth century A.D. and slid into oblivion by the time the Inca Empire rose to dominate the Andes .
Famous for carving in the Peruvian desert hundreds of geometric lines and images of animals and birds that are best viewed from the air, the Nazca people built Cahuachi as a ceremonial center, molding pyramids, temples and plazas from the desert itself.
There, priests led ceremonies including human sacrifices, drawing people from across the region.
Between 300 and 350 A.D., two natural disasters -- a powerful flood and a devastating earthquake -- hit Cahuachi. The site lost its sacred power to the Nazca, who then abandoned the area.
But before leaving, they sealed all monuments and buried them under the desert sand.
"Up to now, we have completely unearthed and restored a huge asymmetrical pyramid, known as the Grand Pyramid. A terraced temple and a smaller pyramid are in an advanced state of excavation," Giuseppe Orefici, an archaeologist who has spent decades excavating Cahuachi and has also worked with the CNR researchers, wrote in the conference paper.
Featuring a 300-by-328-foot base, the newly discovered pyramid consists of at least "four degrading terraces which suggest a truncated pyramid similar to the Grand Pyramid." With seven levels, this imposing monument was sculpted from the landscape and enhanced by large adobe walls.
"This is an interesting finding. As with the Grand Pyramid, it is likely that also this pyramid contains the remains of human sacrifices," Andrea Drusini, an anthropologist at Padova University , told Discovery News.
In previous excavations at Cahuachi, Drusini found some 20 severed "offering heads" at various locations inside the Grand Pyramid.
"They have circular holes cut into the forehead and were perfectly prepared from an anatomical point of view," Drusini said.
The researchers are now investigating other buried structures next to the newly discovered pyramid.
"This innovative technology opens up new perspectives for the detection of buried adobe monuments in Cahuachi and elsewhere," said Masini. "Once we have more information about the size and shape of the structures, we might turn to virtual archaeology to bring the pyramid and its nearby structures back to life."
Cavers in Mexico confront extreme conditions and find extraordinary beauty.
By Neil Shea
National Geographic Staff
Photograph by Carsten Peter, Speleoresearch & Films
In a nearly empty cantina in a dark desert town, the short, drunk man makes his pitch. Beside him on the billiards table sits a chunk of rock the size of home plate. Dozens of purple and white crystals push up from it like shards of glass. "Yours for $300," he says. "No? One hundred. A steal!" The three or four other patrons glance past their beers, thinking it over: Should they offer their crystals too? Rock dust on the green felt, cowboy ballads on the jukebox. Above the bar, a sign reads, "Happy Hour: 8 a.m. to 9 p.m."
This remote part of northern Mexico, an hour or so south of Chihuahua, is famous for crystals, and paychecks at the local lead and silver mine, where almost everyone works, are meager enough to inspire a black market. "Thirty dollars." He leans in. "Ten." It's hard to take him seriously. Earlier in the day, in a cave deep below the bar, I crawled among the world's largest crystals, a forest of them, broad and thick, some more than 30 feet long and half a million years old. So clear, so luminous, they seemed extraterrestrial. They make the chunk on the pool table seem dull as a paperweight.
Nothing compares with the giants found in Cueva de los Cristales, or Cave of Crystals. The limestone cavern and its glittering beams were discovered in 2000 by a pair of brothers drilling nearly a thousand feet below ground in the Naica mine, one of Mexico's most productive, yielding tons of lead and silver each year. The brothers were astonished by their find, but it was not without precedent. The geologic processes that create lead and silver also provide raw materials for crystals, and at Naica, miners had hammered into chambers of impressive, though much smaller, crystals before. But as news spread of the massive crystals' discovery, the question confronting scientists became: How did they grow so big?
It takes 20 minutes to get to the cave entrance by van through a winding mine shaft. A screen drops from the van's ceiling and Michael Jackson videos play, a feature designed to entertain visitors as they descend into darkness and heat. In many caves and mines the temperature remains constant and cool, but the Naica mine gets hotter with depth because it lies above an intrusion of magma about a mile below the surface. Within the cave itself, the temperature leaps to 112 degrees Fahrenheit with 90 to 100 percent humidity—hot enough that each visit carries the risk of heatstroke. By the time we reach the entrance, everyone glistens with sweat.
In a nearly empty cantina in a dark desert town, the short, drunk man makes his pitch. Beside him on tPreparing to enter the cave is like gearing up for a space walk. I pull on a vest with more than a dozen palm-size ice packs sewn into pockets across the chest and back. Then another vest to insulate the ice against the heat. Then, over everything, a bright orange caving suit. A helmet, a headlamp, a respirator mask blowing ice-cooled air. Gloves, boots. Even for cavers cocooned in all this protective gear, the heat is exhausting and dangerous; most trips inside last no more than 20 minutes. Giovanni Badino, a physicist from the Italian exploration group La Venta, leads us in.
Fallen obelisks, pillars of light, the crystals are enormous, some several feet thick. On the floor and walls are clumps of smaller crystals, sharp as blades and flawlessly transparent. Badino proceeds slowly, careful not to damage the crystals, which are made of selenite, a form of the common mineral gypsum. Selenite is translucent and soft, easily scratched by boot heels, even fingernails. Despite the ice suits, the heat and humidity are oppressive. I remove the mask for a moment and suck in wet, hot air. My lungs want to refuse it. There is a damp, heavy scent of earth and an absolute stillness. Miserable conditions for humans, a perfect nursery for crystals.
In their architecture crystals embody law and order, stacks of molecules assembled according to rigid rules. But crystals also reflect their environment. Spanish crystallographer Juan Manuel García-Ruiz was one of the first to study the Naica crystals beginning in 2001. More familiar with microscopic crystals, García was dizzied by the proportions of the Naica giants. By examining bubbles of liquid trapped inside the crystals, García and his colleagues pieced together the story of the crystals' growth. For hundreds of thousands of years, groundwater saturated with calcium sulfate filtered through the many caves at Naica, warmed by heat from the magma below. As the magma cooled, water temperature inside the cave eventually stabilized at about 136°F. At this temperature minerals in the water began converting to selenite, molecules of which were laid down like tiny bricks to form crystals. In other caves under the mountain, the temperature fluctuated or the environment was somehow disturbed, resulting in different and smaller crystals. But inside the Cave of Crystals, conditions remained unchanged for millennia. Above ground, volcanoes exploded and ice sheets pulverized the continents. Human generations came and went. Below, enwombed in silence and near complete stasis, the crystals steadily grew. Only around 1985, when miners using massive pumps lowered the water table and unknowingly drained the cave, did the process of accretion stop.
In the presence of such beauty and strangeness, people cast around for familiar metaphors. Staring at the crystals, García decided the cavern reminded him of a cathedral; he called it the Sistine Chapel of crystals. In both cathedrals and crystals there's a sense of permanence and tranquility that transcends the buzz of surface life. In both there is the suggestion of worlds beyond us.
Now, in the cave, a team of scientists and explorers is conducting research and working on a documentary. Stein-Erik Lauritzen, a professor of geology at the University of Bergen in Norway, is retrieving samples for uranium-thorium dating. His preliminary research suggests the largest of the crystals are about 600,000 years old. Penelope Boston, an associate professor of cave and karst science at New Mexico Tech, searches for microbes that might live among the crystals. In some of them, tiny bubbles of suspended fluid—the kind García studied—sparkle in our lights. They are little time capsules: Italian scientists led by Anna Maria Mercuri extracted pollen that may have been trapped within these inclusions. The grains appear to be 30,000 years old and suggest that this part of Mexico was once covered not by desert but by forest.
One long, slender beam bears a deep scar from where someone tried to cut through it. I imagine a miner dripping and alone in the smothering silence, his weak headlamp bouncing with each saw stroke. Collectors might pay tens of thousands of dollars for a crystal from this cave. Whoever he was, he quit before he could sever the crystal, and mine owners later installed a heavy steel door to deter looters. So far it has worked, but who knows if it will last. Miners, after all, have access to drills and explosives. And while mining and construction projects can be halted to save archaeological relics, minerals in Mexico have no such protection.
The crystals could also be threatened by the lack of water. When the cave was filled, water helped support and preserve the beams. Now, with the cave empty and open to air, they may over time bend or crack under their own weight and become dull, as gases such as carbon dioxide wash in. The director of the mine told me his company, Peñoles, is dedicated to preserving them, but the company's main interest isn't crystals, and the basic activities of mining—blasting, trucks stirring up dust—threaten the gallery. Badino and others hope to convince the company to do more (lobbying for UNESCO World Heritage status has been mentioned), but so far the crystals exist in limbo, probably more famous outside Mexico than within.
We stop for a moment to rest. Everything around us glitters; it is as though we are standing inside a star. Badino turns, and the lines crease at the corners of his eyes. He pulls his mask away. "You know," he says, smiling, "there would be worse places to die."
Cathedral, star, tomb. We look for something to anchor the otherworldly in the familiar. After half an hour we depart, soaked in sweat, our veins throbbing, and a visiting filmmaker asks what it was like. I have a little trouble. He nods, understanding.
"Es como un sueño de niño," he says. "It is like a child's dream."
Dozens of ancient, densely packed, towns, villages, and hamlets arranged in an organized pattern have been mapped in the Brazilian Amazon, anthropologists announced today.
The finding suggests that vast swathes of "pristine" rain forest may actually have been sophisticated urban landscapes prior to the arrival of European colonists.
"It is very different from what we might expect using certain classic models of urbanism," noted study co-author Michael Heckenberger, an anthropologist at the University of Florida in Gainesville.
Nevertheless, he said, the repeated patterns within and among settlements across the landscape suggest a highly ordered and planned society on par with any medieval European town.
The finding supports a controversial theory that the Amazon River Basin teemed with large societies that were all but obliterated by disease when European colonists arrived in the 15th and 16th centuries.
The isolated tribes that remain in the Amazon today are the last survivors of these once great societies, according to the theory.
If this theory is correct, the networked structure of the ancient settlements may lend insight to better protect and manage the indigenous populations and forests that remain in the Amazon today, scientists said.
Heckenberger and his colleagues from the U.S. and Brazil—including a member of the Kuikuro, an indigenous Amazonian tribe—report their finding today in the journal Science.
Urban Plan
In 1993, Heckenberger lived with the Kuikuro near the headwaters of the Xingu River. Within two weeks of his stay, he learned about the ancient settlements and began a 15-year effort to study and map them in detail.
So far he has identified at least two major clusters—or polities—of towns, villages, and hamlets. Each cluster contains a central seat of ritualistic power with wide roads radiating out to other communities.
Each settlement is organized around a central plaza and linked to others via precisely placed roads. In their heyday, some of the settlements were home to perhaps thousands of people and were about 150 acres (61 hectares) in size.
A major road aligned with the summer solstice intersects each central plaza.
The larger towns, placed at cardinal points from the central seat of power, were walled much like a medieval town, noted Heckenberger. Smaller villages and hamlets were less well defined.
Between the settlements, which today are almost completely overgrown, was a patchwork of agricultural fields for crops such as manioc along with dams and ponds likely used for fish farms.
"The whole landscape is almost like a latticework, the way it is gridded off," Heckenberger said. "The individual centers themselves are much less constructed. It is more patterned at the regional level."
At their height between A.D. 1250 and 1650, the clusters may have housed around 50,000 people, the scientists noted.
According to Heckenberger, the planned structure of these settlements is indicative of the regional planning and political organization that are hallmarks of urban society.
"These are far more planned at the regional level than your average medieval town," he said, noting that rural landscapes in medieval settlements were randomly oriented.
"Here things are oriented at the same angles and distances across the entire landscape."
"Garden Cities"
The research "raises huge and important questions," Susan Hecht, an Amazon specialist at the University of California, Los Angeles, was quoted saying in a related Science news piece written by Charles Mann.
Mann is the author of the 2005 book 1491: New Revelations of the Americas Before Columbus, which describes theories of urban planning in the Amazon.
For one, Hecht was quoted as saying, the research adds further weight to the idea that the Amazon Basin once supported large and complex societies.
Other scientists, notably archaeologist Betty Meggers at the Smithsonian Institution in Washington, D.C., have argued that Amazonian soils were too poor to support large human populations for extended periods.
Hecht said the research also challenges the idea that urbanism means a central, dominant, and powerful city. Smaller, but highly connected settlements may also have been common.
According to study co-author Heckenberger, the clusters of towns in the pre-Columbian Amazon were similar to the system envisioned by British planner Ebenezer Howard in his 1902 book, Garden Cities of Tomorrow.
Howard argued for a system of tightly linked smaller cities instead of large megacities that are an eyesore on the natural world.
"If [he] knew about Xingu, it would have been a chapter in his book," Heckenberger said.
And now that the Amazonian "garden cities" have been found, Heckenberger added, scientists and planners ought to study them closely for alternatives to the modern system that is destroying vast reaches of the Amazon and displacing the last of the region's indigenous tribes.
"We know that we have to come up with alternatives," he said, "so here is a place we may want to look."
