lunes, 22 de diciembre de 2008
Maria Cristina Valsecchi in Rome
More than 10,000 graves containing ancient amphorae, "baby bottles," and the bodies of soldiers who fought the Carthaginians were found near the ancient Greek colony of Himera, in Italy, archaeologists announced recently. (See photos.)
"It's probably the largest Greek necropolis in Sicily," said Stefano Vassallo, the lead archaeologist of the team that made the discoveries, in September.
The ancient burial ground was uncovered during the construction of a railway extension.
"The remains of Himera's buildings had been known and studied for a long time, and we knew there should be some graves. We didn't expect so many graves", said Vassallo, who works for the Italian province of Palermo's government.
"Each [mass grave] contains from 15 to 25 skeletons. They were all young healthy men and they all died a violent death. Some of the skeletons have broken skulls and in some cases we found the tips of the arrows that killed them," Vassallo said.
He thinks the human remains are from soldiers who died fighting the Carthaginians in a famous 480 B.C. battle described by Greek historian Herodotus of Halicarnassus.
He adds that they still don't know the extent of the necropolis or how many graves it contains.
A Rich Town and Two Bloody Battles
Founded in 648 B.C. by Greek settlers, Himera was a rich seaport trading colony. The city was situated on the northern coast of Sicily, a few miles from the Phoenician outpost of Solunto.
"Himera had a privileged role in commercial exchanges between Phoenicians, Greeks, and Etruscans," said Clemente Marconi, professor of Greek art and archaeology at the Institute of Fine Arts at New York University.
In 480 B.C. Carthage, or present-day Tunisia, sent an army against Himera. "Greeks and Carthaginians fought a bloody battle in the plain under the town walls, right on the burial ground," Vassallo said. "People from Himera won."
In 409 B.C., Carthage waged a new war against Himera, conquered, and razed the town. "All the people were slaughtered or deported and the colony never rose again," Vassallo said.
Remains of Adults and Babies
Archaeologists at Himera also unearthed the skeletons of many newborn babies in some of the mass graves.
"Infant mortality was very high at the times," Vassallo said. "We found the tiny skeletons placed inside funerary amphorae, like in a womb, alongside small terracotta vases called guttus, with spouts like present-day feeding bottles."
Researchers will examine the skeletons in an effort to gather information about the population's health, lifestyle, and eating habits.
"People from Himera were very tall, about 175 centimeters [69 inches]," Vassallo said. "Unusual for the times."
New York University's Marconi said he thinks the discovery is extremely important.
"Thanks to the big number of burials, we will gather precious information about funerary rituals in Himera: the way they took care of the bodies, preserved the remains, and perpetuated the memory of the dead. Such rituals reflect social structure," Marconi said.
Finds will be restored and put on display in a new museum to be built in the nearby town of Termini Imerese. The Palermo government is working out a plan to create a national archaeological park to protect the area, Vassallo said.
viernes, 19 de diciembre de 2008
Richard A. Lovett in San Francisco, California
A drilling crew recently cracked through rock layers deep beneath Hawaii and accidentally became the first humans known to have drilled into magma—the melted form of rock that sometimes erupts to the surface as lava—in its natural environment, scientists announced this week.
"This is an unprecedented discovery," said Bruce Marsh, a volcanologist from Johns Hopkins University in Maryland, who will be studying the find.
Normally, he said, volcanologists have to do "postmortem studies" of long-solidified magmas or study active lava during volcanic eruptions.
But this time they'd found magma in its natural environment—something Marsh described as nearly as exciting as a paleontologist finding a dinosaur frolicking on a remote island.
"This is my Jurassic Park," he said at a meeting of the American Geophysical Union meeting in San Francisco.
The find was made 1.5 miles (2.5 kilometers) underground during exploratory drilling for geothermal energy.
The crew hit something unusual during routine operations at the Puna Geothermal Venture, owned by Ormat Technologies, Inc., of Reno, Nevada.
When the workers tried to resume drilling, they discovered that magma had risen about 25 feet (8 meters) up the pipe they'd inserted.
The rock solidified into a clear glassy substance, apparently because it chilled quickly after hitting groundwater.
Scientists had long known that magma chambers must lie in the vicinity of the drill site. The drilling was being conducted for an existing geothermal power plant built to harvest heat from the world's most active volcanic zone, Kilauea volcano, which has been spewing lava continuously since 1983.
Don Thomas, a geochemist from the University of Hawaii's Center of the Study of Active Volcanoes, said it was just a matter of time until some drilling operation there struck hot magma.
But to have it actually happen is "tremendously exciting," said Thomas, who was not part of the discovery team.
In addition, researchers found that the magma is made of dacite, a type of rock that's a precursor to granite, rather than the basalt that forms most of Hawaii.
"If we had hit basalt, that would not have been a big surprise," said William Teplow, a consulting geologist at U.S. Geothermal, Inc., who is assisting on the project.
Scientists have long believed that dacite can separate from basaltic magma to form granitic rocks. But they'd never expected to see the process in operation.
"This may be the first time that the generation of granite has actually been observed taking place in nature," Teplow said. "This is important because it's the process that differentiates the continental granitic crust from the more primitive oceanic basaltic crust."
Volcanologist Marsh is excited by the prospects for further study.
"This is just the tip of the iceberg," he said. "We don't know where it's going to lead, but it's a golden opportunity."
It might even be possible to do experiments inside the magma.
"This could be the first magma observatory in the Earth," Marsh said. "This is a singular event of first contact with inner Earth, where magma lives."
With an estimated temperature of 1,900°F (1,050°C), the magma is also valuable as a high-quality heat source for geothermal energy production.
"But the first thing is to get the science," said Lucien Bronicki, Ormat's chair and chief technology officer.
Johns Hopkins's Marsh added that the magma body is big enough that tapping it for energy shouldn't interfere with future research.
"The drill hole is just a pinprick on an elephant's back," he said.
jueves, 18 de diciembre de 2008
Richard A. Lovett
Saturn's moon Titan has odd clouds forming downwind of its lakes—apparently much like clouds seen near North America's Great Lakes, scientists said Monday.
The clouds appear to form from liquid evaporating from the lakes, which then recondense over land, said Mike Brown, a planetary astronomer at the California Institute of Technology.
Near the Great Lakes, similar ribbons of clouds called lake effect clouds form downwind on cold winter days, according to data from NASA's Cassini orbiter.
"Titan is like Buffalo, [New York], without the Bills," Brown quipped.
(Related: "Huge Space Lake Confirmed on Saturn's Moon Titan" [July 31, 2008].)
Scientists have long been interested in a cloud cap above Titan's north pole.
The cloud cap's main layer sits about 40 to 50 kilometers (about 25 to 30 miles) above the moon's surface.
But recent measurements have found another cloud layer—apparently made of the chemical compound methane—about about 6 to 12 miles (10 to 20 kilometers) below that.
"If you look closely at [these] clouds, you see knots and streaks in them," Brown said at an American Geophysical Union meeting in San Francisco.
"They change very rapidly."
In addition to observing lake effect cloud shapes on Titan, Brown noticed that the supposed lake effect clouds only occur downwind of a high-latitude region known to have large lakes.
The clouds tend to cluster particularly densely above a hilly region near the lakes, in keeping with the behavior of Earth's lake effect clouds.
"You never see them to be on the other side [of the moon] or [directly] over the lakes," he said.
He noted, though, that the Cassini spacecraft's flybys have tended to pass more frequently over the downwind region, so it is possible that clouds elsewhere might have escaped observation. And Brown admitted he hasn't proven that the clouds are undoubtedly created by lakes.
But, he said, "I'm sure this is a plausible explanation." Proving it may take a few more years of observation, he added.
The find is another example of the many Earthlike processes that have been found to be operating on Titan, said Ralph Lorenz, a planetary scientist from Johns Hopkins University who was not involved in the study.
"The physical conditions and working materials are different, but the processes themselves and the phenomena that result—whether sand dunes, river channels, or rain clouds—are remarkably similar," he said in an email.
Ultimately, the clouds may also help scientists determine whether liquid methane or liquid ethane makes up Titan's lakes.
The apparent methane lake effect clouds detected under the cloud cap could be formed by either type of lake, experts say.
In the case of methane lakes, warm methane would evaporate into colder air passing over the lakes—exactly what happens on Earth.
But ethane lakes could also form methane lake effect clouds by warming the atmosphere as air blows across the lakes, causing air to rise until clouds condense.
Viewed over a short time frame, these two processes produce very similar looking clouds.
But as Titan's seasons progress through their slow, 16-year cycle, methane and ethane lakes would cool differently, producing different cloud patters as the seasons change.
"Over time, we'll be able to watch these things," Brown said
Scientists have discovered what they say is a completely unexpected new giant dinosaur that lived 70 million years ago in Argentina.
At 16.5 to 21 feet long (5 to 6.5 meters) long, depending on its tail size, Austroraptor cabazai is among the largest of the slender, carnivorous, two-legged dinosaurs called raptors, said Fernando Novas, the lead researcher behind the discovery.
The dinosaur's incomplete skeleton—including head, neck, back, and foot bones—was extracted from rocks in the far-southern Patagonia region.
Novas and colleagues were able to virtually reconstruct Austroraptor's complete skeleton, by using the dinosaur's closest relatives as references, said Novas, who received funding for his work from the National Geographic Society's Committee for Research and Exploration. (The National Geographic Society owns National Geographic News.)
The new raptor, or dromaeosaur, belongs to a South American dromaeosaur group known as the unenlagiines, Novas said.
In contrast to their relatives in the Northern Hemisphere, including the Velociraptors from Jurassic Park, unenlagiines had long, low heads and small conical teeth.
"It's the first documentation of giant raptors in Patagonia measuring 5 meters [16.5 feet] or more," Novas said. "No one expected this, it's a new lineage."
The researchers call Austroraptor "bizarre" because of its short arms, which, along with its large size, distinguishes the new raptor from its unenlagiine relatives.
Novas says the new raptor is the first ever found with short arms.
Its shorter arms and more robust thigh bones, which supported the heavy animal, rule out any possibility of flying, Novas said. Smaller, longer-armed crow- and turkey-size relatives in Patagoni probably did fly, he added.
The size of the Austroraptor probably made it a vicious predator, said Paul Sereno, a paleontologist at the University of Chicago. The new find places raptors in the "big league" of dinosaurs, he said.
"This was a monster raptor that makes the Velociraptor look like kid's play," said Sereno, also a National Geographic Explorer-in-Residence. "At five meters long with a sickle-shaped claw, it was an amazing predator."
"Normally you'd hold an ostrich-size raptor's skull in your hand. This one's skull is almost a meter long."
The new fossils, combined with new finds from China, show that dromaeosaurs "weren't trying to become birds—they were, like all animals, diversifying over time," said Thomas Holtz, a vertebrate paleontologist from the University of Maryland.
The new dinosaur also has a "weird" long skull, Holtz said.
"On first glance it looks like a pterodactyl," he said. "In fact, there has been a small and closely related dinosaur found in South America which has a similar skull. This suggests the whole radiation of southern dromaeosaurs have these long tapering skulls.
"What it does show is that we think we know a lot about the raptors, but even a relatively familiar group of dinosaurs continues to surprise us with their diversity," Holtz added.
Suddenly, the world of southern raptors looks a lot bigger and more complex.
Not only was the Southern Hemisphere home to giant raptors as well as smaller, birdlike specimens, but those large southern raptors were still living at a time when their northern counterparts had died off, Novas said.
"It means that raptors here had very different evolutionary paths from those up north," he said.
"This Austroraptor shows us that here in South America giant raptors evolved and survived until the end of the dinosaur age.
"This new evidence clearly indicates that South America was the site of a very prolific lineage of carnivorous dromaeosaurs, whose evolutionary history now begins to reveal itself," Novas added.
Northern dromaeosaurs had taller, shorter heads with fewer, but stronger, blade-like teeth.
The new raptor represents the "the largest dromaesaurid discovered in the Southern Hemisphere," according to a paper by Novas and colleagues published today in the journal Proceedings of the Royal Society of London.
Seventy million years ago Patagonia was a series of plains crossed by rivers filled with fish and turtles, whose fossils were found alongside Austroraptor, Novas said.
Living in this fertile land alongside duck-billed herbivores such as titanosaurs and hadrosaurs, Austroraptor preyed on larger animals than its smaller relatives, thanks to its increased heft and girth, he said.
Turns History Upside-Down
Because paleontologists have found mostly smaller crow- and turkey-size raptors in South America, the new find turns the evolutionary history of raptors—northern and southern—upside-down, said Novas, who is based out of Museo Argentino de Ciencias Naturales in Buenos Aires.
miércoles, 17 de diciembre de 2008
Towering above their surroundings, Mars' massive volcanoes are symbols that the quiescent planet was once fiery and dynamic.
Now new research suggests that before the planet cooled off, it played host to a bizarre form of plate tectonics unlike any the solar system has seen.
Plate tectonics is key to sustaining life on Earth. Wherever crust is born in the deep sea, or destroyed as it dives back into the the mantle in an endless loop of recycling, volcanoes erupt gases and nutrients that regulate climate and continuously renew life.
One-third Earth's size, Mars is too diminutive to hold enough heat energy to sustain tectonics for very long. But billions of years ago its crust slid around like a rigid skin on a molten interior, according to Shijie Zhong of the University of Colorado in Boulder.
"Earth is the only planet with plates that move around," Zhong said. "But you can have the entire shell of crust rotating with respect to the interior."
In a paper published this week in the journal Nature Geoscience, Zhong used a computer simulation of the planet to argue this "single plate" form of tectonics was fueled by uneven convection in the mantle. In the northern hemisphere, cool material sank down toward the planet's core, while hot buoyant material rose toward the surface in the southern hemisphere.
Zhong's theory explains one of the biggest mysteries of Mars -- why the southern half of the planet is so much higher than the north. The hot, rising material pushed up the crust and made it thicker. Where it was hottest, a plume of magma erupted on to the surface as a volcano.
Today, three of those volcanoes form a straight line across the Tharsis Rise highlands. As the planet's shell of crust rolled to the south between 4.1 and 3.7 billion years ago, Zhong thinks a stationary plume of magma punched holes in the crust, erupting volcanoes in a row one after another, much like the Hawaiian Islands on Earth.Testing this theory will be difficult, though. New surveys of the red planet could look for fracture patterns in the crust that indicate the entire planet's surface once moved as one. The rocks' magnetic signature could also hint at ancient motion.
The finding also has implications for other planets.
"There may be a lot of other places in the solar system where this is important," Frances Nimmo of the University of California, Santa Cruz said. "Mercury, Venus, even some moons -- almost everywhere you look outside of Earth you have single-plate bodies."
An inscribed limestone block might have solved one of history's greatest mysteries -- who fathered the boy pharaoh King Tut.
"We can now say that Tutankhamun was the child of Akhenaten," Zahi Hawass, chief of Egypt's Supreme Council of Antiquities, told Discovery News.
The finding offers evidence against another leading theory that King Tut was sired by the minor king Smenkhkare.
Hawass discovered the missing part of a broken limestone block a few months ago in a storeroom at el Ashmunein, a village on the west bank of the Nile some 150 miles south of Cairo.
Once reassembled, the slab has become "an accurate piece of evidence that proves Tut lived in el Amarna with Akhenaten and he married his wife, Ankhesenamun," while living in el Amarna, Hawass said. The text also suggests that the young Tutankhamun married his father's daughter -- his half sister.
"The block shows the young Tutankhamun and his wife, Ankhesenamun, seated together. The text identifies Tutankhamun as the 'king's son of his body, Tutankhaten,' and his wife as the 'king's daughter of his body, Ankhesenaten,'" Hawass said.
"We know that the only king to whom the text could refer as the father of both children is Akhenaten, himself. We know from other sources that Ankhesenamun was the daughter of Akhenaten and Nefertiti. Now, because of this block, we can say that Tutankhamun was the child of Akhenaten as well," Hawass said.
Found among other sandstone slabs in the storeroom of El Ashmunein's archaeological site, the block was used in the construction of the temple of Thoth during the reign of Ramesses II, who ruled around 1279-1213 B.C.
But the block wasn't freshly cut by the workers of the temple. Instead, it was recycled and brought there from el Amarna, along with some other thousand blocks, originally used to build the Amarna temples.
Now known as el Amarna, the city was once called Akhetaten after the "heretic" pharaoh Akhenaten (1353-1336 B.C.) had established the capital of his kingdom, introducing a monotheistic religion that overthrew the pantheon of the gods to worship the sun god Aton.
When Akhenaten died, a state decree was issued to purposefully destroy Amarna and its building materials were distributed for use elsewhere.
ccording to Hawass, the block comes from the temple of Aton in Amarna and the forms of the inscribed names clearly date it to the reign of Akhenaten.
The best-known pharaoh of ancient Egypt, King Tut has been puzzling scientists ever since his mummy- and treasure-packed tomb was discovered in 1922 the Valley of the Kings by British archaeologist Howard Carter.
Only a few facts about his life are known.
While he lived in el Amarna, his name was Tutankhaton ("honoring Aton" -- the sun god).
When he ascended the throne in 1333 B.C., at the age of nine, and moved to Thebes, he changed his name to Tutankamun ("honoring Amun" -- a traditional cult).
As the last male in the family, his death in 1325 B.C. at age 19 ended the 18th dynasty -- probably the greatest of the Egyptian royal families -- and gave way to military rulers.
Mapping out the lineage of the Egyptian pharaohs is one of Hawass's latest challenges. King Tut has been either credited to be the son of Akhenaten or the offspring of Amenhotep III, who was Akhenaten's father.
Doubts also remain about King Tut's mother. Scholars have long debated whether he is the son of Kiya, Akhenaten's minor wife, or Queen Nefertiti, Akhenaten's other wife.
Egyptian researchers are currently carrying out DNA testing on two mummified fetuses found in King Tut's tomb, believed to be his offspring.
"If the fetus DNA matches King Tut's DNA and Ankhesenamun's DNA, then we would know that they shared the same mother," Hawass said.
According to Swiss anatomist and paleopathologist Frank Ruhli, head of the Swiss Mummy Project at the University of Zurich, Hawass' finding is very important.
"It supports one of my favorite theories about King Tut's parentage. DNA of proven relatives would help if it matches with the one of King Tut,"
Evidence is mounting that Saturn's moon Enceladus has water somewhere beneath its frozen surface, analysis of recent flybys by the Cassini spacecraft shows.
"It's virtually impossible that we don't have liquid water some place in the body," Carolyn Porco, the head of Cassini's imaging team at the Space Science Institute in Boulder, Colo., said during a press conference at the American Geophysical Union conference in San Francisco this week.
One of the biggest surprises of Cassini's ongoing mission at Saturn was the discovery of geyser-like jets shooting streams of organics-laced ice and water vapor out into space. Cassini flew as close as 15.5 miles above one of Enceladus' fractures, warm spots scientists call "tiger stripes," during its last pass over the moon in October.
The jets of ice particles of water vapor spew from vents inside the fractures.
Scientists have enough information to conclude that the face of Enceladus changes over time, with some vents opening and others closing due to tectonic forces similar to what occurs on the floors of some of Earth's oceans where volcanic material wells up to create new crust.
On Enceladus, however, the spreading is almost entirely in one direction, like a conveyor belt, rather than multi-directional like on Earth.
"We are not certain about the geological mechanisms that control the spreading," said Paul Helfenstein with Cornell University in New York.
"It's very unusual. You wouldn't find something like this on Earth."
The mechanism is similar enough to Earth-like systems, however, to suggest that subsurface heat and convection are involved, he added.
martes, 16 de diciembre de 2008
Archaeologists have unearthed the skull of a young woman in northern Greece who is believed to have undergone head surgery in the third century, Greek news media reported Wednesday.
A Greek team discovered the skeleton at an ancient cemetery in Veria, with the skull including an injury that led them to conclude the surgery had been performed.
"We think that there was a complex surgical intervention that only an experienced doctor could have performed," said Ioannis Graikos, the head of the archaeological dig.
"Medical treatment on the human body in the Roman Veria is part of a long tradition that began with Hippocrates up to Roman doctor Celsus and Galen," he said, cited in the Ta Nea newspaper.
Hippocrates is believed to have lived in the fifth century BC, Celsus between 25 BC to 50 AD, and Galen from 131 to 201.
The procedure believed to have been carried out was a trepanation, an ancient form of surgery to address head injuries or illnesses.
In 2003, Greek archaeologists discovered a man's skull in a tomb on the Aegean island of Chios from the second century B.C. that had also undergone a trepanation.
The patient was believed to have lived a number of years after the operation.
Another trepanation was discovered in 2006 in Thrace on a young woman from the eighth century B.C., believed injured by a weapon.
British archaeologists have unearthed an ancient skull carrying a startling surprise -- an unusually well-preserved brain.
Scientists said Friday that the mass of gray matter was more than 2,000 years old -- the oldest ever discovered in Britain. One expert unconnected with the find called it "a real freak of preservation."
The skull was severed from its owner sometime before the Roman invasion of Britain and found in a muddy pit during a dig at the University of York in northern England this fall, according to Richard Hall, a director of York Archaeological Trust.
Finds officer Rachel Cubbitt realized the skull might contain a brain when she felt something move inside the cranium as she was cleaning it, Hall said. She looked through the skull's base and spotted an unusual yellow substance inside. Scans at York Hospital confirmed the presence of brain tissu
Italian researchers have discovered the pottery center where the oil lamps that lighted the ancient Roman empire were made.
Evidence of the pottery workshops emerged in Modena, in central-northern Italy, during construction work to build a residential complex near the ancient walls of the city.
"We found a large ancient Roman dumping filled with pottery scraps. There were vases, bottles, bricks, but most of all, hundreds of oil lamps, each bearing their maker's name," Donato Labate, the archaeologist in charge of the dig, told Discovery News.
Firmalampen, or "factory lamps," were one of the first mass-produced goods in Roman times and they carried brand names clearly stamped on their clay bottoms.
The ancient dumping in Modena contained lamps by the most famous brands of the time: Strobili, Communis, Phoetaspi, Eucarpi and Fortis.
All these manufacturers had their products sold on the markets of three continents. Fortis was the trendiest of all pottery brands and its products were used up to the end of the second century A.D.
How Stuff Works: Rome and the Roman Empire
"It was indeed a commercial success. Fortis gained such a name for its lamps that its stamp was copied and reproduced throughout the empire. It was one of the earliest examples of pirated brands," Labate said.
Scholars have long thought that the fashionable Fortis originated from Modena -- then called Mutina -- but until now no evidence had been found for that claim.
"We know now for sure that Fortis came from Mutina. The city was a major pottery center, a cluster of pottery workshops, as the variety of brand names on the newly discovered items testifies," Labate said.
Labate added that kilns were located outside the city walls to prevent fires from breaking out in the city.
The ancient dumping contained other important objects, such as a fine terracotta statuette depicting Hercules as he captures the Erymanthian Boar, and 14 lead bullets which were probably used in the Battle of Mutina in 43 B.C. During that battle, Decimus Brutus, one of Julius Caesar's assassins, defeated the besieging Mark Antony with the help of Octavian, the future Roman Emperor Augustus.
"This is an extraordinary discovery, since it provides unique archaeological evidence which confirms historical accounts," Luigi Malnati, superintendent of archaeological heritage in Emilia Romagna, told Discovery News.
The oil lamps and the other newly discovered objects will be displayed in a permanent show at the Archaeological and Ethnological Museum in Modena at the end of the month.
lunes, 15 de diciembre de 2008
A spacecraft has captured an image of what may be the first drop of liquid ever observed on an extraterrestrial surface.
Among the pictures snapped by the Huygens probe after landing on Saturn's moon Titan in 2005, one appears to show a dewdrop made of methane that briefly formed on the edge of the probe itself. Scientists think heat from the probe caused humid air to rise and condense on the cold edge of the craft.
Though Huygens had a hand in producing it, the methane drop is still the first liquid directly detected at the surface anywhere beyond Earth.
Like Earth, Titan has clouds, lakes, and river channels, and it may be the only other place in the solar system where liquid evaporates from the surface and returns as rain. "Aside from Earth, it's the most exciting world there is," said lead author Erich Karkoschka of the University of Arizona in Tucson.
The Cassini space probe, which took data from above the moon after separating from the Huygens lander, detected what scientists believe are lakes of liquid methane on Titan's surface. Microbes that eat methane thrive on Earth, and scientists think pools of methane could be comfortable homes for similar organisms on Titan.
Because Titan's current atmosphere is a lot like the early Earth's, the lakes could be a lab for studying the origins and early evolution of life.
Astronomers have speculated about whether the moon's methane rain falls in violent thunderstorms, light drizzles, or some other form since they found methane in the atmosphere in 1983. So far, no one has caught it on camera.
The hundreds of images snapped by Huygens, from the time it hit the atmosphere until its power ran out an hour after it landed, revealed only faint, wispy clouds that looked nothing like rain clouds, Karkoschka said.
None of the images showed evidence that it had rained during the previous few years, according to an analysis to be published in the journal Icarus. And some images suggested that Titan’s lower atmosphere was full of small dust particles, which would have been cleared out by rain.
But the scientists noticed light splotches in some of the pictures that hadn’t been there moments before. Some of them had spots that initially looked like raindrops because of their uniform size and smooth edges, but analysis showed they were most likely electronic imprints created by cosmic rays.
However, Karkoschka said, "One of those spots was so big that it really cannot be a cosmic ray." He concluded that it was a real, short-lived dewdrop, so close to the camera that it must have condensed on a cold metal shield designed to protect the camera lens from direct sunlight.
Robert West, a planetary scientist at the Jet Propulsion Lab in Pasadena, California, thinks the dewdrop is “a cute observation,” but he’s more interested in the lack of rainfall. “There are reports in the literature that concluded there is a drizzle going on near the surface,” he said. “The fact that Huygens didn’t find anything is significant.”
The standard model of physics got it right when it predicted where the mass of ordinary matter comes from, according to a massive new computational effort. Particle physics explains that the bulk of atoms is made up of protons and neutrons, which are themselves composed of smaller particles known as quarks, which in turn are bound by gluons. The odd thing is this: the mass of gluons is zero and the mass of quarks [accounts for] only five percent. Where, therefore, is the missing 95 percent? [AFP]
The answer, according to theory, is that the energy from the interactions between quarks and gluons accounts for the excess mass (because as Einstein’s famous E=mc² equation proved, energy and mass are equivalent). Gluons are the carriers of the strong nuclear force that binds three quarks together to form one proton or neutron; these gluons are constantly popping into existence and disappearing again. The energy of these vacuum fluctuations has to be included in the total mass of the proton and neutron [New Scientist]. The new study finally crunched the numbers on how much energy is created in these fluctuations and confirmed the theory, but it took a supercomputer over a year to do so.
The theory that describes the interactions of quarks and gluons is known as quantum chromodynamics, or QCD. These exchanges bind quarks together by changing a quark property known as color charge. This charge is similar to electric charge but comes in three different types, whimsically referred to as red, green and blue. Six different types of quarks interact with eight varieties of gluons to create a panoply of elementary particles [Science News]. Calculating these interactions was a massive task, as researchers explain in an article in Science [subscription required]. The team used more than a year of time on the parallel computer network at Jülich, which can handle 200 teraflops - or 200 trillion arithmetical calculations per second [New Scientist].
But what, you may be saying, of the Higgs boson? The Higgs is often mentioned as an elusive particle that endows other particles with mass, and the Large Hadron Collider will search for it when it starts up again next year. But the Higgs is thought to explain only where the mass of the quarks themselves comes from. The new work confirms that the mass of the stuff around us is due only in very small part to the masses of quarks themselves. Most of it comes from the way they interact [Nature News].
Genghis Khan Mausoleum in Ordos
Genghis Khan ; Mongolian: Ч Chinggis Khaan, IPA: , Činggis Qaɣan; born Temüjin , was the Mongol founder, Khan (ruler) and posthumously declared Khagan (emperor) of the Mongol Empire, the largest contiguous empire in history.
He came to power by uniting many of the nomadic tribes of northeast Asia. After founding the Mongol Empire and being proclaimed "Genghis Khan", he started the Mongol invasions and raids of the Kara-Khitan Khanate, Caucasus, Khwarezmid Empire, Western Xia and Jin dynasties. During his life, the Mongol Empire eventually occupied a substantial portion of Central Asia.
Before Genghis Khan died, he assigned Ogedei Khan as his successor and split his empire into khanates among his sons and grandsons. He died in 1227 after defeating the Tanguts. He was buried in an unmarked grave somewhere in Mongolia at a location unknown. His descendants went on to stretch the Mongol Empire across most of Eurasia by conquering and/or creating vassal states out of all of modern-day China, Korea, the Caucasus, Central Asian countries, and substantial portions of modern Eastern Europe and the Middle East.
"The greatest happiness is to vanquish your enemies, to chase them before you, to rob them of their wealth, to see those dear to them bathed in tears, to clasp to your bosom their wives and daughters"
- Genghis Khan
Temüjin was related on his father's side to Qabul Khan, Ambaghai and Qutula Khan who had headed the Mongol confederation. When the Jin Dynasty switched support from the Mongols to the Tatars in 1161, they destroyed Qabul Khan. Genghis' father, Yesugei (leader of the Borjigin and nephew to Ambaghai and Qutula Khan), emerged as the head of the ruling clan of the Mongols, but this position was contested by the rival Tayichi’ud clan, who descended directly from Ambaghai. When the Tatars grew too powerful after 1161, the Jin switched their support from the Tatars to the Keraits.
The Onon River, Mongolia in autumn, a region where Temüjin was born and grew up.
Because of the lack of contemporary written records, there is very little factual information about the early life of Temüjin. The few sources that provide insight into this period are often conflicting.
Temüjin was born 1165 in a Mongol tribe near Burkhan Khaldun mountain and the Onon and Kherlen rivers in modern day Mongolia, not far from its current capital Ulaanbaatar. The Secret History of the Mongols purports that Temüjin was born with a blood clot grasped in his fist, a sign that he was destined to become a great leader. He was the third-oldest son of his father Yesükhei, a minor tribal chief of the Kiyad and an ally of Ong Khan of the Kerait tribe, and the oldest son of his mother Hoelun. According to the Secret History, Temüjin was named after a Tatar chieftain that his father had just captured. The name also suggests that they may have been descended from a family of blacksmiths (see section Name and title below).
Yesükhei's clan was called Borjigin , and Hoelun was from the Olkhunut tribe. Like other tribes, they were nomads. Because his father was a chieftain, as were his predecessors, Temüjin was of a noble background. This relatively higher social standing made it easier to solicit help from and eventually consolidate the other Mongol tribes. No accurate portraits of Genghis exist today, and any surviving depictions are considered to be artistic interpretations. Persian historian Rashid al-Din recorded in his "Chronicles" that the legendary "glittering" ancestor of Genghis was tall, long-bearded, red-haired, and green-eyed. Rashid al-Din also described the first meeting of Genghis and Kublai Khan, when Genghis was shocked to find Kublai had not inherited his red hair. Genghis's Borjigid clan, al-Din also revealed, had a legend involving their clan: it began as the result of an affair (technically a virgin birth) between Alan-ko and a stranger to her land, a glittering man who happened to have red hair and bluish-green eyes. Modern historian Paul Ratchnevsky has suggested in his Genghis biography that the "glittering man" may have been from the Kyrgyz people, who historically displayed these same characteristics. Controversies aside, the closest depiction generally accepted by most historians is the portrait currently in the National Palace Museum in Taipei, Taiwan
Early life and family
Temüjin had three brothers named Khasar (or Qasar), Khajiun, and Temüge, and one sister named Temülen (or Temülin), as well as two half-brothers named Bekhter and Belgutei. Like many of the nomads of Mongolia, Temüjin's early life was difficult. At nine years old, as part of the marriage arrangement, he was delivered by his father to the family of his future wife Börte, who was a member of the same tribe as his mother. He was to live there in service to Sansar, the head of the household, until he reached the marriageable age of 12. While heading home, his father was poisoned during a meal with the neighbouring Tatars, who had long been enemies of the Mongols. Temüjin returned home to claim the position of khan. However, his father's tribe refused to be led by a boy so young. They abandoned Hoelun and her children, leaving them without protection.
For the next several years, Hoelun and her children lived in poverty, surviving primarily on wild fruits, marmots, and other small game hunted by Temüjin and his brothers. It was during one hunting excursion that 13-year-old Temüjin killed his half-brother, Bekhter, during a fight which resulted from a dispute over hunting spoils. This incident cemented his position as head of the household.
In another incident in 1182 he was captured in a raid and held prisoner by his father's former allies, the Bjartskular ("wolves"). The Bjartskular enslaved Temüjin (reportedly with a cangue), but with the help of a sympathetic watcher, the father of Chilaun (who would later become a general of Genghis Khan), he was able to escape from the ger by hiding in a river crevice. It was around this time that Jelme and Arslan, two of Genghis Khan's future generals, joined forces with him. Along with his brothers, they provided the manpower needed for early expansion. Temüjin's reputation also became relatively widespread after his escape from the Bjartskular.
At this time, none of the tribal confederations of Mongolia were united politically, and arranged marriages were often used to solidify temporary alliances. Temujin grew up observing the tough political climate of Mongolia, surrounded by tribal warfare, thievery, raids, corruption and continuing acts of revenge carried out between the various confederations, all compounded by interference from foreign forces such as the Chinese dynasties to the south. Temüjin's mother Ho'elun taught him many lessons about the unstable political climate of Mongolia, especially the need for alliances.
As previously arranged by his father, Temüjin married Börte of the Olkut'hun tribe when he was around 16 in order to cement alliances between their respective tribes. Börte had four sons, Jochi (1185–1226), Chagatai (1187—1241), Ögedei (1189—1241), and Tolui (1190–1232). Genghis Khan also had many other children with his other wives, but they were excluded from the succession, and records of daughters are nonexistent. Soon after Börte's marriage to Temüjin, she was kidnapped by the Tartars, and reportedly given away as a wife. Temüjin rescued her with the help of his friend and future rival, Jamuka, and his protector, Ong Khan of the Kerait tribe. She gave birth to a son, Jochi, nine months later, clouding the issue of his parentage. Despite speculation over Jochi, Börte would be his only empress, though Temüjin did follow tradition by taking several morganatic wives.
Genghis Khan's religion is widely speculated to be Shamanism or Tengriism, which was very likely among nomadic Mongol-Turkic tribes of Central Asia. But he was very tolerant religiously, and interested to learn philosophical and moral lessons from other religions. To do so, he consulted among others with Christian missionaries, Muslim merchants, and the Taoist monk Qiu Chuji.
Uniting the confederations
The Central Asian plateau (north of China) around the time of Temüjin (the early 1200s) was divided into several tribes or confederations, among them Naimans, Merkits, Uyghurs, Tatars, Mongols, and Keraits, that were all prominent in their own right and often unfriendly toward each other as evidenced by random raids, revenges, and plundering.
Temüjin began his slow ascent to power by offering himself as an ally (or, according to others sources, a vassal) to his father's anda (sworn brother or blood brother) Toghrul, who was Khan of the Kerait, and is better known by the Chinese title Ong Khan (or "Wang Khan"), which the Jin Empire granted him in 1197. This relationship was first reinforced when Börte was captured by the Merkits; it was Toghrul to whom Temüjin turned for support. In response, Toghrul offered his vassal 20,000 of his Kerait warriors and suggested that he also involve his childhood friend Jamuka, who had himself become Khan (ruler) of his own tribe, the Jadaran. Although the campaign was successful and led to the recapture of Börte and utter defeat of the Merkits, it also paved the way for the split between the childhood friends, Temüjin and Jamuka. Temüjin had became blood brother (anda) with Jamuka earlier, and they had vowed to remain eternally faithful.
The main opponents of the Mongol confederation (traditionally the "Mongols") around 1200 were the Naimans to the west, the Merkits to the north, Tanguts to the south, and the Jin and Tatars to the east. By 1190, Temüjin, his followers, and their advisors, had united the smaller Mongol confederation only. In his rule and his conquest of rival tribes, Temüjin broke with Mongol tradition in a few crucial ways. He delegated authority based on merit and loyalty, rather than family ties. As an incentive for absolute obedience and following his rule of law, the Yassa code, Temüjin promised civilians and soldiers wealth from future possible war spoils. As he defeated rival tribes, he didn't drive away enemy soldiers and abandon the rest. Instead, he took the conquered tribe under his protection and integrated its members into his own tribe. He would even have his mother adopt orphans from the conquered tribe, bringing them into his family. These political innovations inspired great loyalty among the conquered people, making Temüjin stronger with each victory.
Toghrul's (Wang Khan) son Senggum was jealous of Temüjin's growing power, and his affinity with his father. He allegedly planned to assassinate Temüjin. Toghrul, though allegedly saved on multiple occasions by Temüjin, gave in to his son and became uncooperative with Temüjin. Temüjin learned of Senggum's intentions and eventually defeated him and his loyalists. One of the later ruptures between Toghrul and Temüjin was Toghrul's refusal to give his daughter in marriage to Jochi, the eldest son of Temüjin, a sign of disrespect in the Mongolian culture. This act led to the split between both factions, and was a prelude to war. Toghrul allied himself with Jamuka, who already opposed Temüjin's forces; however the internal dispute between Toghrul and Jamuka, plus the desertion of a number of their allies to Temüjin, led to Toghrul's defeat. Jamuka escaped during the conflict. This defeat was a catalyst for the fall and eventual dissolution of the Kerait tribe.
The next direct threat to Temüjin was the Naimans (Naiman Mongols), with whom Jamuka and his followers took refuge. The Naimans did not surrender, although enough sectors again voluntarily sided with Temüjin. In 1201, a kurultai elected Jamuka as Gur Khan, "universal ruler", a title used by the rulers of the Kara-Khitan Khanate. Jamuka's assumption of this title was the final breach with Temüjin, and Jamuka formed a coalition of tribes to oppose him. Before the conflict, however, several generals abandoned Jamuka, including Subutai, Jelme's well-known younger brother. After several battles, Jamuka was finally turned over to Temüjin by his own men in 1206.
According to the Secret History, Temüjin again offered his friendship to Jamuka, asking him to return to his side. Temüjin had killed the men who betrayed Jamuka, stating that he did not want disloyal men in his army. Jamuka refused the offer of friendship and reunion, saying that there can only be one Sun in the sky, and he asked for a noble death. The custom is to die without spilling blood, which is granted by breaking the back. Jamuka requested this form of death, despite the fact that in the past Jamuka had been infamously known to have boiled his opponent's generals alive.
The rest of the Merkit clan that sided with the Naimans were defeated by Subutai, a member of Temüjin's personal guard who would later become one of the successful commanders of Genghis Khan. The Naimans' defeat left Genghis Khan as the sole ruler of the Mongol plains, which means all the prominent confederations fell and/or united under Temüjin's Mongol confederation. Accounts of Genghis Khan's life are marked by claims of a series of betrayals and conspiracies. These include rifts with his early allies such as Jamuka (who also wanted to be a ruler of Mongol tribes) and Wang Khan (his and his father's ally), his son Jochi, and problems with the most important Shaman who was allegedly trying to break him up with brother Qasar who was serving Genghis Khan loyally. Many modern scholars doubt that all of the conspiracies existed and suggest that Genghis Khan was probably inclined towards paranoia as a result of his experiences.
His military strategies showed a deep interest in gathering good intelligence and understanding the motivations of his rivals as exemplified by his extensive spy network and Yam route systems. He seemed to be a quick student, adopting new technologies and ideas that he encountered, such as siege warfare from the Chinese. Many legends claim that Genghis Khan always was at the front in battles, but these may not be historically accurate.
As a result by 1206 Temüjin had managed to unite or subdue the Merkits, Naimans, Mongols, Keraits, Tatars, Uyghurs and disparate other smaller tribes under his rule. It was a monumental feat for the "Mongols" (as they became known collectively). At a Kurultai, a council of Mongol chiefs, he was acknowledged as "Khan" of the consolidated tribes and took the new title "Genghis Khan". The title Khagan was not conferred on Genghis until after his death, when his son and successor, Ögedei took the title for himself and extended it posthumously to his father (as he was also to be posthumously declared the founder of the Yuan Dynasty). This unification of all confederations by Genghis Khan established peace between previously warring tribes and a single political and military force under Genghis Khan.
Death and burial
Mongol Empire in 1227 at Genghis Khan's death
In 1227, after defeating the Tangut people, Genghis Khan died (according to The Secret History of the Mongols). The reason for his death is uncertain and speculations abound. Some historians maintain that he fell off his horse during a horseback pursuit from the land of present day Egypt due to battle wounds and physical fatigue, ultimately dying of his injuries. Others contend that he was felled by a protracted illness such as pneumonia. The Galician-Volhynian Chronicle alleges he was killed by the Tanguts in battle. Later Mongol chronicles connect Genghis' death with a Tangut princess taken as war booty. One chronicle from the early 17th century even relates that the princess hid a small pair of pliers inside her vagina, and hurt the Great Khan so badly that he died. Some Mongol authors have doubted this version and suspected it to be an invention by the rival Oirads.
Genghis Khan asked to be buried without markings, according to the customs of his tribe. After he died, his body was returned to Mongolia and presumably to his birthplace in Khentii Aimag, where many assume he is buried somewhere close to the Onon River and the Burkhan Khaldun mountain (part of the Kentii mountain range). According to legend, the funeral escort killed anyone and anything across their path to conceal where he was finally buried. The Genghis Khan Mausoleum, constructed many years after his death, is his memorial, but not his burial site.
On October 6, 2004, a joint Japanese-Mongolian archaeological dig uncovered what is believed to be Genghis Khan's palace in rural Mongolia, which raises the possibility of actually locating the ruler's long-lost burial site.Folklore says that a river was diverted over his grave to make it impossible to find (the same manner of burial of Sumerian King Gilgamesh of Uruk.) Other tales state that his grave was stampeded over by many horses, over which trees were then planted, and the permafrost also did its part in hiding the burial site.
Genghis Khan left behind an army of more than 129,000 men; 28,000 were given to his various brothers and his sons. Tolui, his youngest son, inherited more than 100,000 men. This force contained the bulk of the elite Mongolian cavalry. By tradition, the youngest son inherits his father's property. Jochi, Chagatai, Ögedei Khan, and Kulan's son Gelejian received armies of 4,000 men each. His mother and the descendants of his three brothers received 3,000 men each.
Dinosaurs were airheads—and that's not just because they had tiny brains, a new study says.
New 3-D scans of the skulls of Tyrannosaurus rex and other dinosaurs reveal the creatures had more empty space inside their heads than previously thought.
These air spaces made the skulls light but strong and could have helped dinosaurs breathe, communicate, and hunt.
The extra room may even have paved the way for flight in some species.
"Air is a neglected system that is actually an important contributor to what animals do," said study co-author Lawrence Witmer, a paleontologist at Ohio University in Athens.
The research is detailed in a recent issue of the journal The Anatomical Record.
Witmer and colleague Ryan Ridgely made detailed CT scans of air cavities in the skulls of two predators, T. rex and Majungasaurus; and two ankylosaurs, Panoplosaurus and Euoplocephalus, both plant-eaters with armored bodies and short snouts. (See an illustration of another ankylosaur species.)
The results mark the first time scientists were able to accurately estimate the weight of a dinosaur's head.
A T. rex head, for example, would have weighed more than 1,100 pounds (about 500 kilograms), close to the average weight of an adult cow, Witmer and colleagues found.
Until now, paleontologists had to make do with estimates for the weight of dinosaur heads, said Tom Holtz, a paleontologist at the University of Maryland who was not involved in the research.
"Larry's team is able to calculate a volume for the skull, so they can constrain the weight far more securely," Holtz said. "This is the next best thing to having a fleshy T. rex head to dissect."
Witmer estimates that T. rex's head would have been 18 percent heavier if not for the air spaces in its skull.
This savings may have allowed T. rex to pack more muscle onto its head, which possibly strengthened its bite and allowed it to tackle bigger prey.
The nasal airways in the ankylosaurs, however, were surprisingly convoluted. It was as if "crazy straws" had been rammed up the creatures' snouts, Witmer said.
These winding airways were often located next to large blood vessels.
"Whenever we see that, it raises the possibility that we're looking at heat transfer," Witmer said.
This setup would have allowed hot blood circulating through the creatures' heads to dump excess heat into the airways, helping to cool their brains and the rest of their bodies.
The transferred heat also could have warmed up air the dinosaurs breathed, making gas exchange in the lungs easier.
In addition, the twisty nasal passages may have acted as resonating chambers for sounds.
The two ankylosaur species examined had slightly different airways, so their voices would have been subtly different, Witmer said.
The research could provide new clues about how dinosaurs achieved flight.
Some of the new study's research subjects were theropods, the group of dinosaurs from which modern birds are descended.
(Related: "T. Rex Protein "Confirms" Bird-Dinosaur Link" [April 24, 2008].)
"Very often people have thought that birds have hollow bones because they fly, but it could be the other way around," Witmer said.
"They could have evolved hollow bones for other reasons, and that gave them the lower body mass necessary to take to the air."
Hans-Dieter Sues is a dinosaur expert at the Smithsonian National Museum of Natural History in Washington, D.C., who also did not participate in the research.
Witmer "certainly makes a strong case for paranasal sinuses [air-filled spaces within the skull] reducing the weight of the skull in certain dinosaurs," Sues said.
Sues cautioned, however, that "such functional hypotheses are difficult to test even in living species, including our own."
viernes, 12 de diciembre de 2008
The Maya Cosmic Prophecy: From Sensation to Sensibility
Maya Scholars, in Mexico, Guatemala, Belize, Honduras, El Salvador and North America, have been watching with amusement and dismay as self-styled experts proclaim that ancient Maya prophets foretold an earth-shattering happening to occur December 21, 2012. This predicted phenomenon gets described in contradictory but often cataclysmic fashion--as an ecological collapse, a sunspot storm, a rare cosmic conjunction of the earth, sun, and the galactic center, a new and awesome stage of our evolution, and even a sudden reversal of the Earth's magnetic field which will erase all our computer drives. One even predicts the earth's initiation into a Galactic Federation, whose elders have been accelerating our evolution with a "galactic beam" for the last 5000 years. In sum, the world as we know it will suddenly come to a screeching halt.
These predictions are alleged to be prophecies by so-called "Ancient Mayans" whose "astronomically precise" calendar supposedly terminates on that date. According to such accounts, these mysterious Maya geniuses appeared suddenly, built an extraordinary civilization, designed in it clues for us, and then suddenly, inexplicably, vanished, as if they had completed their terrestrial mission. These same experts claim special credibility for the Maya prophecies by asserting that these historic sages, with their possible extraterrestrial origins, had tapped into an astonishing esoteric wisdom.
Could any of this be true?
The credibility of those claims deserves rational attention-which is what I intend to provide. Neither mystic nor prophet, I am a Mayanist. More specifically, I am a professional art historian and an epigrapher (less formally, a glypher), one who can read and write Maya hieroglyphs. For over a decade, I have focused my scholarly research specifically on Maya culture and writing, making some surprising discoveries that can present a more definitive perspective on the prophecies of the ancient Maya seers. As we approach the critical year, it is time to offer a more viable account of the Maya prophecy and expose both the fallacies and ethnocentricism tainting the current sensational accounts.
Here I intend to explain what we actually know about (1) Maya knowledge and attitudes, both ancient and modern, (2) the date 184.108.40.206.0. and (3) their many Creation stories and prophecies. I shall draw from recent decipherment, ethnography, interviews with Maya priests and knowledge-keepers, and especially from their surviving prophetic literature. That literature includes The Books of Chilam Balam, among others, the pre-Columbian Codices, and ancient inscriptions. The evidence is sometimes fragmentary and often puzzling to us moderns, at least at first. But I believe the effort will be worth it.
First, let me affirm that the year 2012 does hold particular significance in Mayan scholarship. Those of us who study the ancient and modern Maya — anthropologists, archaeologists, art historians, linguists, historians, amateurs, collectors — have been anticipating the end of the Maya Great Cycle for some time. We write it 220.127.116.11.0 4 Ajaw 3 K'ank'in. We have known for half a century that this date probably correlates to December 21 (or December 23) in the year 2012 in the Gregorian calendar.
jueves, 11 de diciembre de 2008
These new, undersea worms don't have eyes to turn you into stone.
But their resemblance to snake-haired Medusa (above) wasn't lost on discoverer Ana Hilário, who plans to name at least one after the mythological Greek monster.
Hilário, of Portugal's University of Aveiro, and colleagues recently found 20 species of the tiny worms, called frenulates, in mud volcanoes in the Gulf of Cádiz, an arm of the Atlantic Ocean southwest of Spain.
Mud volcanoes are places where methane-filled fluids seep from the seafloor, providing energy for "exceptionally rich ecosystems," Hilário said in an email.
(Related: "Giant Deep-Sea Volcano With 'Moat of Death' Found" [April 14, 2006].)
But scientists know little about the elusive frenulates, tube-dwelling worms that survive thanks to bacteria that live inside a special organ in their bodies.
The worms absorb chemicals such as methane from sediment and deliver the substances, via their blood, to the bacteria, which in turn produce organic carbon. The carbon nourishes both creatures.
Hilario has already named another genus from the expedition Bobmarleya—the worm's "dreadlocked" appearance reminded her of the Jamaican singer, she said.
miércoles, 10 de diciembre de 2008
The recent discovery of carbon dioxide in the atmosphere of a Jupiter-like planet 63 light-years away has some researchers excited that we may soon find habitable exoplanets—worlds circling other stars.
According to lead author Mark Swain of NASA's Jet Propulsion Laboratory in Pasadena, California, carbon dioxide is a biomarker, a molecule associated with life as we know it.
This first discovery of the molecule on a far-flung planet, he said, is a step toward eventually finding biomarkers on smaller, more Earthlike worlds.
Last March, Swain and colleagues had announced the first detection of another biologically important chemical, methane, on the same exoplanet, as well as confirmation of water vapor.
"Methane is a potential marker [of life], as is water, as is carbon dioxide," Swain said. "So, three of the biggies we've already detected."
But not all planetary scientists are embracing the idea that finding chemicals such as carbon dioxide and methane on a distant planet is enough to say it is habitable.
On Earth, for example, carbon dioxide traps a certain amount of sunlight, keeping temperatures warm enough to support life. But on Venus, too much carbon dioxide creates a killing heat—average temperatures there reach 864 degrees Fahrenheit (462 degrees Celsius).
"To me, a CO2-dominated atmosphere says the planet would certainly be more like Venus than Earth," said Ellen Stofan, a planetary geologist for Proxemy Research in Maryland and a member of NASA's Cassini science team.
"To say it precludes life or guarantees life are both going out on a limb—we just don't know. But it is intriguing!"
Swain and colleagues made the CO2 discovery while studying radiation from an exoplanet dubbed HD 189733b.
The planet periodically transits—or passes in front of—its host star, giving observers a measurement of the star and planet's combined light. By subtracting the light from the star alone from the combined measurement, astronomers can "see" the planet's light.
Reading signatures from this light then told astronomers the chemical composition of the planet's atmosphere.
Swain acknowledges that HD 189733b is too big, gaseous, and hot to host life as we know it.
But the fact that we are now able to find biomarkers such as carbon dioxide on worlds so far away means that we'll know what to look for when reading light signatures from smaller, rocky planets like Earth.
So far, the most elusive biomarker on any exoplanet has been oxygen.
The only thing that drives the presence of free oxygen molecules on Earth is plants, points out Geoff Marcy, an astronomer at the University of California, Berkeley, who was not involved with the carbon dioxide study.
Without plants to generate O2, all the oxygen in the atmosphere would eventually react with other elements and be trapped.
"If you could detect free oxygen [on an exoplanet], then you'd have something. That would be remarkable," Marcy said.
Astronomers searching for habitable exoplanets must first face the daunting challenge of finding distant Earthlike worlds.
Astronomers think at least half of the sunlike stars in our galaxy could host habitable terrestrial worlds.
But most of the more than 330 exoplanets found since the first discovery in 1995 have been large gaseous bodies that resemble Jupiter. Plenty have also been detected that are closer to the size of Saturn or Neptune, down to 17 times the mass of Earth.
Planets down to about five times the mass of Earth have been much rarer discoveries, and Berkeley's Marcy believes rocky planets—the holy grail, he calls them—are likely to be no more than three times the mass of Earth.
For now planetary detection methods are best suited to spotting larger bodies.
So far 270 of the known exoplanets have been detected using the so-called Doppler wobble, a shift in light from the parent star caused by a massive planet's gravitational tug.
About 50 or 60 exoplanets have been found because they transit their parent stars, and about 5 worlds have been spotted using a bizarre physical phenomenon predicted by Einstein's theory of relativity: gravitational lensing.
This is when light from other stars is bent by the gravitational tug of an object in the foreground that is orbiting a star too faint for us to see from Earth.
Marcy has high hopes that NASA's upcoming Kepler mission will bring the quest for rocky exoplanets closer to its goal.
"It's the hottest thing going, there's nothing even close to it," said Marcy, who is part of the Kepler science working group.
Set to launch on March 5, the space telescope is designed to find other Earths by staring at the constellation Cygnus and detecting stars that dim due to transiting planets.
Cygnus was chosen because it contains a large number of stars and won't be obscured by the sun at any time of the year.
The probe's photometers are sensitive enough to catch minute changes in light that result during a transit by a small planet, and its "eye" can see a hundred thousand stars at once.
"If Kepler finds that most stars have a terrestrial planet in the habitable zone, then there must be billions of such planets in our galaxy and life could be ubiquitous," said William Borucki, Kepler mission lead scientist at NASA.
"On the other hand, if Kepler finds no terrestrial planets or extremely few, then life of any type must be very rare. We could be the only sentient life."
Even if Kepler proves there are scores of habitable worlds within Cygnus, the constellation contains stars that are a hundred to more than a thousand light-years away.
That means there won't be much to do but point radio telescopes toward them and scan for spillover from alien communication technologies.
(Related: "Are Neighborhood Aliens Listening to Earth Radio?" [September 7, 2006].)
That's because travel to any of its planets using current propulsion methods wouldn't be possible, at least not in a single generation, Marcy noted.
The idea requires acceptance of "having your great grandchildren be the ones who arrive at Alpha Centauri, not you."
Meanwhile, Notre Dame's Bennett points out that heavy elements—the main ingredients for planetary systems—are most common near the center of the galaxy, which is billions of years older than our solar system.
This ups the chances that any alien civilizations are much more advanced technologically than humans.
"If they're a few billion years ahead of us," Bennett said, "it's more of a question of them getting here than us getting there."
Some pre-Hispanic cultures in South America had elaborate celebrations at their cemeteries, complete with feasting and drinking grounds much like modern barbecue pits, according to a new archaeological study.
Excavations of 12th- and-13th-century burial mounds in the highlands of Brazil and Argentina revealed numerous earthen ovens. The finds suggest that the graves were also sites of regular festivals held to commemorate the death of the community's chief.
"After they buried an important person on the burial grounds, they feasted on meat that had been steamed in the earth ovens and drank maize beer," said archaeologist and study co-author José Iriarte.
Large rings of raised earth surround the mounds, with paths leading to their centers. The rings are composed of a series of the ovens, which were built up over generations.
"This monumental tradition spread across kilometers, from southern São Paulo state in Brazil to Río Grande del Sur in Argentina," added Iriarte, a professor of archaeology at the University of Exeter in the U.K.
The Jê people, who occupied the area Iriarte refers to during the 12th and 13th centuries, are recorded as having often consumed an alcoholic beverage of maize and honey."We think we are in the presence of a sizable, regionally organized population."
Along with the ovens, the team found big subterranean houses complete with roofs in a region rich with diverse plant and animal species, a desirable place to settle down, Iriarte added.
They were able to combine hunting and gathering, horticulture, fishing, and slash-and-burn agriculture to sustain large populations," said Iriarte, who has been conducting archaeological digs in the area for years and is considered an expert on Jê culture.
Michael Heckenberger, an archaeologist and anthropologist at the University of Florida who specializes in the Amazon, explained that the environment in southern Brazil was previously believed to be difficult for sustaining large populations.
"But I think it is very clear that [Iriarte and colleagues] have demonstrated that these were more than marginal tribes," Heckenberger said.
"This is part of a growing body of research that shows that groups of people in lowlands in Brazil had large, socially complex groupings, sociopolitical organization and social patterns including feasting," he added.
The new evidence also shows that, opposed to other peoples in the region, the Jê had settlements and celebrations that were more dynamic and permanent, Heckenberger added.
(See related: "Ancient Amazon Cities Found; Were Vast Urban Network" [August 28, 2008].)
Other evidence has shown that the burial parties were reserved for renowned chiefs—who inherited their leadership positions—demonstrating "a moderate degree of political complexity," said Iriarte, whose work was funded in part by the National Geographic Society's Committee for Research and Exploration. (National Geographic News is owned by the National Geographic Society.)
The chief's son usually sponsored the festivities, Iriarte added. That way, "the relative reaffirmed ties to ancestors and to his position in society."
The Jê were also reaffirming their territory, according to Iriarte. Around A.D. 1000, several other groups of people were migrating around the Brazilian and Argentine highlands. The burial monuments, situated on hilltops or ridges, clearly outlined Jê communities, Iriarte said.
"They are really marking their land," he added.
"They carried out these festivities in a period of the year when pine nuts [eaten at celebrations] and maize were abundant," Iriarte added. "These were important resources to them."
Researchers found ceramic vessels such as bowls and small drinking cylinders that still contained residues of corn. Unidentifiable animal remains were also discovered.
The findings are published in the December issue of the journal Antiquity.
Archaeologists traditionally viewed the Jeê people as small, nomadic groups. But these discoveries prove that theory wrong, Iriarte said.
"This is an unexpected development in this part of southern America," he said
martes, 9 de diciembre de 2008
Mati Milstein in Tel Aviv
The remains of an ancient gate have pinpointed the location of the biblical city Sha'arayim, say archaeologists working in Israel.
In the Bible young David, a future king, is described as battling Goliath in the Elah Valley near Sha'arayim.
ancient biblical city and gate
The fortified gate at the Elah Fortress—the second to be found at the site—proves the existence of Sha'arayim, which means "two gates" in Hebrew, said Hebrew University archaeologist Yosef Garfinkel.
"All the sites from this period uncovered so far had only one gate. We have two gates and this is very unusual," Garfinkel said.
The gate, constructed of stones weighing up to ten tons, is located on the site's eastern side, facing Jerusalem.
Evidence of King David
The discovery is the second recent find to be made at the Elah Fortress—known as Khirbet Qeiyafa in Arabic—which is located near the present-day Israeli city of Bet Shemesh.
In October, Garfinkel revealed a 3,000-year-old pottery shard with text believed to be Hebrew—then hailed as the most important archaeological discovery in Israel since the Dead Sea Scrolls.
Initial carbon-14 dating of olive pits found at the site, as well as analysis of pottery remains, placed the text to between 1000 and 975 B.C.—the time King David would have lived.
Garfinkel believes the discovery provides further evidence that the fortified city or outpost was part of a centralized governmental system administered by King David, head of the Kingdom of Israel.
The fortress is the first site found from the Iron Age in what was once territory controlled by King David. Sha'arayim is also mentioned three times in the Bible and is twice linked to David.
"Everything comes together—the geography, the Bible, and the radiometric dating. It's no coincidence," Garfinkel said.
Other archaeologists received news of the second gate's discovery with interest, but they warned of jumping to conclusions.
Amos Kloner, an Israel studies professor at Bar Ilan University, once served as district archaeologist around the Elah site but is not involved in the current excavations.
"This is an initial idea, all aspects of which must be examined," he said. "[But] it doesn't matter if there is a second gate … This provides no indication of a Judean population there."
It's not known whether the Judeans or the Philistines controlled the strategic fortress overlooking the Elah Valley.
Team leader Garfinkel believes the site was most likely the westernmost outpost maintained by the Kingdom of Judea, which controlled land in southwest Asia and Palestine and was a predecessor to the Kingdom of Israel.
Israel Knohl, also not involved in the Elah excavations, is a Biblical studies expert at Hebrew University of Jerusalem.
"The main problem with this site is that we still need unequivocal proof that it was a city of Judeans," Knohl said.
The discovery of the second gate "is of secondary importance … At the moment, we cannot determine with certainty this was Sha'arayim or that it was a Judean city."
Scholars know almost nothing of life in Sha'arayim.
"If you ask me what life was like even in Jerusalem during the time of King David, that we can't say," Knohl said. "When it comes to smaller [and less important] locations, we simply don't know."
Garfinkel said he will continue to explore the Elah site in search of further evidence.
"Maybe we'll find an inscription on the gate indicating who built the city: 'I David, son of Yishai, built this city,'" he said with a laugh.
lunes, 8 de diciembre de 2008
Tisisat Falls presents an idyllic scene. The Blue Nile crashes over the cataract in the lush forests of northwest Ethiopia.
Photograph by Diego Lezama Orezzoli/CORBIS
160,000-Year-Old Child Suggests Modern Humans Got Early Start
Modern humans may have evolved more than 80,000 years earlier than previously thought, according to a new study of sophisticated stone tools found in Ethiopia.
The tools were uncovered in the 1970s at the archaeological site of Gademotta, in the Ethiopian Rift Valley. But it was not until this year that new dating techniques revealed the tools to be far older than the oldest known Homo sapien bones, which are around 195,000 years old.
Using argon-argon dating—a technique that compares different isotopes of the element argon—researchers determined that the volcanic ash layers entombing the tools at Gademotta date back at least 276,000 years.
Many of the tools found are small blades, made using a technique that is thought to require complex cognitive abilities and nimble fingers, according to study co-author and Berkeley Geochronology Center director Paul Renne.
Some archaeologists believe that these tools and similar ones found elsewhere are associated with the emergence of the modern human species, Homo sapiens.
"It seems that we were technologically more advanced at an earlier time that we had previously thought," said study co-author Leah Morgan, from the University of California, Berkeley.
The findings are published in the December issue of the journal Geology.
Gademotta was an attractive place for people to settle, due to its close proximity to fresh water in Lake Ziway and access to a source of hard, black volcanic glass, known as obsidian.
"Due to its lack of crystalline structure, obsidian glass is one of the best raw materials to use for making tools," Morgan explained.
In many parts of the world, archaeologists see a leap around 300,000 years ago in Stone Age technology from the large and crude hand-axes and picks of the so-called Acheulean period to the more delicate and diverse points and blades of the Middle Stone Age.
At other sites in Ethiopia, such as Herto in the Afar region northeast of Gademotta, the transition does not occur until much later, around 160,000 years ago, according to argon dating. This variety in dates supports the idea of a gradual transition in technology.
A modern analogy might be the transition from ox-carts to automobiles, which is virtually complete in North America and northern Europe, but is still underway in the developing world," said study co-author Renne, who received funding for the Gadmotta analysis from the National Geographic Society's Committee for Research and Exploration. (The National Geographic Society owns National Geographic News.)
Morgan, of UC Berkeley, speculates that the readily available obsidian at Gademotta may explain why the technological revolution occurred so early there.
Complicated family tree
The lack of bones at Gademotta makes it difficult to determine who made these specialist tools. Some archaeologists believe it had to be Homo sapiens, while other experts think that other human species may have had the required mental capability and manual dexterity.
Regardless of who made the tools, the dates help to fill a key gap in the archaeological record, according to some experts.
"The new dates from Gademotta help us to understand the timing of an important behavioral change in human evolution," said Christian Tryon, a professor of anthropology from New York University, who wasn't involved in the study.
If anything, the story has now become more complex, added Laura Basell, an archaeologist at the University of Oxford in the U.K.
"The new date for Gademotta changes how we think about human evolution, because it shows how much more complicated the situation is than we previously thought," Basell said.
"It is not possible to simply associate specific species with particular technologies and plot them in a line from archaic to modern."
viernes, 5 de diciembre de 2008
Andrew Bossone in Cairo
ON TV Egypt Unwrapped: Mystery of the Screaming Man airs Friday, November 21, at 9 p.m. ET on the National Geographic Channel.
An Egyptian mummy who died wearing a pained facial expression could be Prince Pentewere, suspected of plotting the murder of his father, Pharaoh Ramses III, according to a new analysis.
Recent examinations of the mummy, found in 1886 and now located in the Egyptian Museum in Cairo, have helped archaeologists piece together a story of attempted murder, suicide, and conspiracy.
"Two forces were acting upon this mummy: one to get rid of him and the other to try to preserve him," said Bob Brier, an archaeologist at the University of Long Island in New York who examined the body this year.
Called both "Unknown Man E" and the "Screaming Mummy" because of his open jaw and agonized expression, the mummy has baffled researchers since it was first uncovered.
Several archaeologists have proposed theories about the mummy's cause of death, saying he might have been buried alive or poisoned, or that he was a murdered Hittite prince during the reign of Tutankhamen.
Archaeologists now agree, however, that mummies are commonly found with their jaws open as a result of their heads falling back after death.
The Screaming Mummy was unlikely to have been a Hittite prince because that man probably would not have been mummified, according to those examining the corpse.
"They're not going to mummify this guy if they murdered him," Brier said. "They're going to get rid of the body."
The theory about poison, on the other hand, has not been totally ruled out.
Papyrus documents indicate a trial that took place in the 12th century B.C. for a wife of Pharaoh Ramses III. She was charged with conspiracy to murder the pharoah and put her son Pentewere in his place.
The mummy of Unknown Man E suggests an ignoble death, much like Pentewere would have received if this story were true, according to the archaeological team.
"We found this mummy is covered in sheepskin," said Zahi Hawass, secretary general of Egypt's Supreme Council of Antiquities and a National Geographic Explorer-in-Residence.
"In the mind of the ancient Egyptian. … To cover with sheepskin means he was not clean, he did something [bad] in his life," Hawass added.
Pentewere could have been sentenced to death by poison, after the murderous plans were revealed, according to Hawass and Brier.
The Unknown Man E was found without a grave marking, which would have prevented him from reaching the afterlife—a possible additional punishment for being part of a murder plot.
However, the denial of an afterlife contradicts careful mummification—something usually reserved for celebrated members of society, said Brier.
Brier, a mummification expert, believes the Unknown Man E was mummified quickly because he did not have his brain or internal organs removed, nor was he completely dehydrated. Additionally, crude methods were used for his mummification.
"[Resin] is normally introduced into the cranium after removing the brain," he explained. But in the case of the Screaming Mummy, new research has shown that resin was poured down the corpse's throat.
"That's kind of a half-hearted or desperate attempt," Brier said.
So why wasn't the body simply disposed of without mummification? An influential person could have cared about the body and made sure it was at least hastily mummified, rather than thrown away.
"For some reason there was an attempt to make sure that he doesn't have an afterlife, and in another attempt somebody cares about him and tried to override that," Brier said.
Archaeologists insist the theory that the Screaming Mummy is Prince Pentewere is still only speculation, and so far have only conducted a CT scan of the mummy.
Hawass said he plans to conduct DNA testing to confirm the connection to Ramses III.