Evidence mounts for quantum criticality theory

A new study by a team of physicists at Rice University, Zhejiang University, Los Alamos National Laboratory, Florida State University and the Max Planck Institute adds to the growing body of evidence supporting a theory that strange electronic behaviors -- including high-temperature superconductivity and heavy fermion physics -- arise from quantum fluctuations of strongly correlated electrons.

The study, which appeared in the Jan. 20 issue of Proceedings of the National Academy of Sciences, describes results from a series of experiments on a layered composite of cerium, rhodium and indium. The experiments tested, for the first time, a prediction from a theory about the origins of quantum criticality that was published by Rice physicist Qimiao Si and colleagues in 2001.

"Our theory was a surprise at the time because it broke with the textbook framework and suggested that a broad range of phenomena -- including high-temperature superconductivity -- can only be explained in terms of the collective behavior of strongly correlated electrons rather than by the more familiar theory based on essentially decoupled electrons," said Si, a co-corresponding author on the new study and Rice's Harry C. and Olga K. Wiess Professor of Physics and Astronomy.

Experimental evidence in support of the theory has mounted over the past decade, and the PNAS study fills yet another gap. In the experiments, researchers probed high-quality samples of a heavy-fermion material known as CeRhIn5.

Heavy fermion materials like CeRhIn5 are prototype systems for quantum criticality. In these materials, electrons tend to act in unison, and even one electron moving through the system causes widespread effects. This "correlated electron" behavior is very different from the electron interactions in a common metal like copper, and physicists have become increasingly convinced that correlated electron behavior plays an important role in phenomena like superconductivity and quantum criticality.

Quantum critical points, near which these strange correlated effects are particularly pronounced, mark a smooth phase change, or transition from one state of matter to another. Just as the melting of ice involves a transition from a solid to a liquid state, the electronic state of quantum materials changes when the material is cooled to a quantum critical point.

The critical temperature of a material can be raised or lowered if the material is chemically altered, placed under high pressure or put into a strong magnet. In the new experiments, which were carried out using the high magnetic field facilities at Los Alamos National Laboratory in New Mexico and at Florida State University, researchers observed a magnetically induced quantum critical point at ambient pressure and compared it to the previously studied case of a pressure-induced quantum critical point.

The nature of the quantum critical point was probed by something called the "Fermi surface," a sort of three-dimensional map that represents the collective energy states of all electrons in the material. When physicists have previously attempted to describe quantum phase transitions using traditional theories, equations dictate that the Fermi surface must change smoothly and gradually as the material passes through the critical point. In that case, most of the electrons on the Fermi surface are still weakly coupled to each other.

In contrast, Si's theory predicts that the Fermi surface undergoes a radical and instantaneous shift at the critical point. The electrons on the entire Fermi surface become strongly coupled, thereby giving rise to the strange-metal properties that allow unusual electronic states, including superconductivity.

A "Fermi surface" is kind of three-dimensional map representing the collective energy states of electrons in a material. These computer-generated illustrations show how the Fermi surface for CeRhIn5 changes, depending upon whether the electrons are strongly interacting (left) or weakly interacting (right). Credit: Q. Si/Rice University and J.X. Zhu/Los Alamos National Laboratory

"We observed exactly the sort of a sharp Fermi surface reconstruction predicted by theory of unconventional quantum criticality," said study co-author Frank Steglich, director of the Max Planck Institute for Chemical Physics of Solids in Dresden, Germany, and also of the Center for Correlated Matter at Zhejiang University in Hangzhou, China.

Zhejiang physicist Huiqiu Yuan, co-corresponding author on the study, said, "Our experiments demonstrate that direct measurements of a Fermi surface can distinguish theoretically proposed models of quantum criticality and point to a universal description of quantum phase transitions."

Read more at Scince Daily

Hydrogen production in extreme bacterium

A researcher at Missouri University of Science and Technology has discovered a bacterium that can produce hydrogen, an element that one day could lessen the world's dependence on oil.

Dr. Melanie Mormile, professor of biological sciences at Missouri S&T, and her team discovered the bacterium Halanaerobium hydrogeninformans in Soap Lake, Washington. It can "produce hydrogen under saline and alkaline conditions in amounts that rival genetically modified organisms," Mormile says.

"Usually, I tend to study the overall microbial ecology of extreme environments, but this particular bacterium has caught my attention," Mormile says. "I intend to study this isolate in greater detail."

Mormile, an expert in the microbial ecology of extreme environments, wasn't searching for a bacterium that could produce hydrogen. Instead, she first became interested in bacteria that could help clean up the environment, especially looking at the extremophiles found in Soap Lake. An extremophile is a microorganism that lives in conditions of extreme temperature, acidity, alkalinity or chemical concentration. Living in such a hostile environment, Halanaerobium hydrogeninformans has metabolic capabilities under conditions that occur at some contaminated waste sites.

With Halanaerobium hydrogeninformans, she expected to find an iron-reducing bacterium and describe a new species. What she found was a new species of bacterium that can produce hydrogen and 1, 3-propanediol under high pH and salinity conditions that might turn out to be valuable industrially. An organic compound, 1, 3-propenediol can be formulated into industrial products including composites, adhesives, laminates and coatings. It's also a solvent and can be used as antifreeze.

The infrastructure isn't in place now for hydrogen to replace gasoline as a fuel for planes, trains and automobiles. But if hydrogen becomes an alternative to gasoline, Halanaerobium hydrogeniformans, mass-produced on an industrial scale, might be one solution -- although it won't be a solution anytime soon.

"It would be great if we got liters and liters of production of hydrogen," Mormile says. "However, we have not been able to scale up yet."

In her first single-author article, Mormile's findings were featured in the Nov. 19 edition of Frontiers in Microbiology.

Read more at Science Daily

50-Foot-Long 'Dragon' Dinosaur Unearthed in China

An enormous 50-foot-long dinosaur named "Dragon of Qijiang" was unearthed by construction workers near Qijiang City, China.

The plant-eating dinosaur, Qijianglong guokr, had an unusual body that was half neck. It lived about 160 million years ago and is described in the latest issue of the Journal of Vertebrate Paleontology.

The construction crew that happened upon the dinosaur remarkably managed to unearth the dinosaur with its head still attached to its long, narrow neck.

"It is rare to find a head and neck of a long-necked dinosaur together because the head is so small and easily detached after the animal dies," co-author Tetsuto Miyashita said in a press release.

"Qijianglong is a cool animal," added Miyashita, who is a University of Alberta paleontologist. "If you imagine a big animal that is half neck, you can see that evolution can do quite extraordinary things."

Most sauropods (i.e. long-necked, plant-eating dinosaurs) have necks that are about one-third the length of their bodies, so "Dragon of Qijiang" sported quite a neck. The researchers determined that its vertebrae were filled with air, making it lighter in weight than the neck bones of other animals.

Interlocking joints between the vertebrae, however, meant that the neck was surprisingly stiff. The researchers suspect that the neck was more mobile going up and down, like a construction crane, than it was moving from side to side.

"Dragon of Qijiang" is classified as a mamenchisaurid, a group of dinosaurs known for their long necks. This type of dinosaur has thus far only been found in Asia.

"Qijianglong shows that long-necked dinosaurs diversified in unique ways in Asia during Jurassic times–something very special was going on in that continent," said Miyashita. "Nowhere else we can find dinosaurs with longer necks than those in China. The new dinosaur tells us that these extreme species thrived in isolation from the rest of the world."

The paleontologists speculate that a sea, or other natural barrier, could have caused the isolation.

The "Dragon" and its kind were survivors, though. As other long-necked dinosaurs bit the dust in Asia, mamenchisaurids thrived, evolving into different types, including this half-neck form.

Read more at Discovery News

BICEP2 Gravitational Wave 'Discovery' Deflates

In online French documents briefly released and then removed last night and confirmed by the European Space Agency today, physicists have announced that last year’s much-publicized ‘discovery’ of gravitational waves embedded in the ‘echo’ of the Big Bang was a misstep.

Preempting the official research paper that is planned to be published next week, the ESA, who manages the Planck space telescope data, has gone on the record to say that the BICEP2 measurements of B-mode polarization in the cosmic microwave background (CMB) was caused not by the presence of primordial gravitational waves, but by obscuring dust inside our own galaxy. The CMB is the left-over ancient radiation from the Big Bang that occurred nearly 14 billion years ago.

“Despite earlier reports of a possible detection, a joint analysis of data from ESA’s Planck satellite and the ground-based BICEP2 and Keck Array experiments has found no conclusive evidence of primordial gravitational waves,” writes an ESA statement.

This null result doesn’t come as a surprise to many scientists in the field, however.

Since the media storm that surrounded one of the would-be biggest cosmological discoveries in modern history in March 2014, the BICEP2 data has been heavily scrutinized. Although the BICEP2 telescope, a US-led project based near the South Pole, is designed to detect the tell-tail ‘wiggle’ in the polarization of CMB radiation caused by the presence of gravitational waves, great care needs to be taken when interpreting the results.

Should gravitational waves be detected, not only would their discovery be monumental, it would also confirm some key models of the universe’s origin, thereby revealing the mechanisms behind inflation — the split-second expansion of the universe immediately after the Big Bang.

However, between us and the outermost reaches of our observable universe there is magnetized material within our own galaxy. Any radiation detected beyond our galaxy has to travel through the interstellar dust and the signal needs to be corrected for. But to correct for our galaxy’s dust, you need to precisely map it first — this is where the European Planck space telescope comes in.

Before it went silent in 2013, Planck was surveying the sky, mapping the CMB. But it was also mapping the intervening magnetic field and dust content of our galaxy. These data are critical to subtract from CMB measurements if B-mode polarization is to be detected. But in March 2014, when the BICEP2 researchers announced their results to the world, the precision Planck dust map was not available.

Now that the Planck survey data has been processed, it seems that the BICEP2 ‘signal’ of gravitational waves is in fact interference caused by galactic dust.

“When we first detected this signal in our data, we relied on models for Galactic dust emission that were available at the time,” said John Kovac, principal investigator of BICEP2 at Harvard University, Cambridge, Mass. “These seemed to indicate that the region of the sky chosen for our observations had dust polarization much lower than the detected signal.”

Now the BICEP2 and Planck teams are working together in hopes to place some limits on how strong any potential gravitational wave signals will be.

“This joint work has shown that the detection of primordial B-modes is no longer robust once the emission from Galactic dust is removed,” added Jean-Loup Puget, principal investigator of the HFI instrument on Planck at the Institut d’Astrophysique Spatiale in Orsay, France.

“So, unfortunately, we have not been able to confirm that the signal is an imprint of cosmic inflation.”

We will have to wait to read the full details behind this latest twist in the BICEP2 results when the joint Planck-BICEP2 paper is published next week, but it seems certain that the original BICEP2 announcement was premature.

It is important to note, however, that this null result doesn’t disprove the existence of gravitational waves, it just confirms, to a high degree of certainty, that BICEP2 hasn’t detected gravitational waves — yet.

“While we haven’t found strong evidence of a signal from primordial gravitational waves in the best observations of CMB polarization that are currently available, this by no means rules out inflation,” said Reno Mandolesi, principal investigator of the LFI instrument on Planck at University of Ferrara, Italy.

Read more at Discovery News

Stunning Supernova Has Bubbly Interior

A new three dimensional model of the Cassiopeia A supernova remnant provides insights into how these massive explosions occur.

The detailed model reveals a bubble-like interior of debris that connects with a bright shell of ejecta arranged in multiple circular structures.

"This is the first time we've actually seen such a complete image of what the interior of this thing looks like," said one of the study's authors Professor Robert Fesen of Dartmouth College in New Hampshire.

"It shows big bubbles, big cavities that others suggested might be there, and this shows they really are."

The study is published in the journal Science.

Cassiopeia A was created 340 years ago when a massive star exploded to form a neutron star, making it a good subject for a cosmic post mortem.

In this type of explosion, known as a core-collapse supernova, the outer layers of the star drop in free fall, reaching speeds of 70,000 kilometers per second, a significant fraction of the speed of light.

Somehow, that material suddenly stops and ends up traveling the other way at up to 10,000 kilometers per second. Scientists call this sudden reversal a "bounce", but until now they've been unsure exactly how it happens.

"We know the core collapses down to form a neutron star, and the rest blows up somehow after that," said Fesen. "But most of our models have had problems blowing up stars because the outer layers of the star collapse into the core and smother the explosion!"

Stellar autopsy

Distant supernovae outside our galaxy are difficult to study because they're so far away.

Fesen and co-author Dr Dan Milisavljevic, of the Harvard-Smithsonian Center for Astrophysics, used near-infrared spectroscopy to measure expansion velocities of extremely faint material inside the supernova remnant, providing the crucial third dimension for the 3D model.

"We're sort of like bomb squad investigators," said Milisavljevic. "We examine the debris to learn what blew up and how it blew up. Our study represents a major step forward in our understanding of how stars actually explode."

The study revealed that cavities in the supernova's interior are caused by plumes of radioactive nickel 56, said Fesen.

"Nickel 56 will eventually decay into iron, and during that decay process a lot of energy is generated. These plumes of nickel move through the non-radioactive material, pushing it away and making cavities.

Read more at Discovery News

Hubble Finds Galaxy's Stars Scattered Far from Home

This mesmerizing observation by the Hubble Space Telescope shows galaxy NGC 7714 in a state of turmoil.

Between 100-200 million years ago, when dinosaurs roamed Earth, NGC 7714 got too close to another galaxy (NGC 7715, out of frame, right) and the extreme tidal forces dragged one of its once-elegant spiral arms deep into intergalactic space. The scattered stars now form a stellar bridge to the second galaxy, exchanging star-forming material.

Both galaxies are approximately 100 million light-years from Earth.

This violent galactic collision wasn’t all bad news for NGC 7714, however. The encounter caused disruption in the interstellar gasses it contains, triggering a wave of new star formation throughout the galactic spirals. The wave of star birth has been captured as bright blue by Hubble’s optics.

Due to the frenzied birth of new stars, astronomers refer to NGC 7714 as a Wolf-Rayet starburst galaxy. Many of the young, massive stars are known as Wolf-Rayets, which as very massive, hot, tumultuous stars that live fast and die young, shedding huge quantities of superheated gases before they erupt as supernovae.

So what started as a violent galactic collision, ended up as a frenzy of star birth that, eventually, will see the Wolf-Rayets explode, seeding NGC 7714 with heavier elements that will go on to form other stars and, ultimately, star systems.

From Discovery News

The World’s Tiniest, Most Adorable Snake Can Curl Up on a Quarter

A threadsnake on its way to the arcade. Do arcades even exist anymore? Let’s say they do, otherwise this caption won’t make sense. Well, come to think of it, this caption doesn’t make sense regardless.

If I learned anything from Honey I Shrunk the Kids, it’s that turning into a human that’s small enough to fit in a Cheerio comes with a unique set of challenges. Scorpions become even bigger jerks than when you’re normal-sized, for instance. And your dad almost eats you because you’re inside a Cheerio.

But what if your wildly irresponsible father hadn’t just left a shrink ray lying around—what if instead evolution had over the millennia shrunk you down, bit by bit, until a beetle seemed a formidable foe? For an answer to that, you’d have to ask the smallest snake in the world, the Barbados threadsnake, which isn’t even recognizable as a serpent anymore. It’s 4 inches long, about as thick as spaghetti, and looks more like a worm than a snake. And the challenges its diminutive size brings are many—save for falling into cereal bowls, of course.

First of all, there’s the matter of feeding. According to Temple University’s S. Blair Hedges, who first described the creature in 2008, the Barbados threadsnake has “a pretty narrow diet because their mouth can barely open. I mean, they’re small to begin with, but then their mouths don’t open like a normal snake. They just barely open up enough to squeeze in a little microscopic insect.”

A threadsnake post-arcade.

While a lot of snakes out there are hunting prey like rodents and amphibians and birds, those things are of course far too big for the threadsnake (there are a few more species other than the Barbados variety, but for brevity’s sake I’ll just refer to it as the threadsnake). Instead, it’s limited to taking on primarily the eggs and larvae of ants and termites. Every so often they’ll go after the adults too, but typically it’s the young.

Threadsnakes are burrowers, spending their days squirming through soft soil, and that may be due in part to another problem that small creatures face. Because the extremely thin snake has a higher ratio of surface area to volume—compared to, say, a polar bear, which has a lower ratio with its bulky body—it’s more susceptible to losing moisture. By kicking back in the wet dirt, the snake can better avoid desiccation (being so bulky, by the way, also helps the polar bear better retain heat).

Also an issue is how they bear their own young. How many eggs a snake can lay varies greatly, the Eastern mud snake here in the States, for instance, can produce as many as 100, but the threadsnake is at the opposite end of the spectrum with a grand total of…one. Mama threadsnake bets on one single egg.

The Western blind snake, Leptotyphlops humilis (which shares a genus with the Barbados threadsnake), and her highly elongated eggs. It’s pink because that’s in style right now.

The Eastern mud snake is 3 feet long and pretty thick, and can thus pack all those eggs in there. But the threadsnake is so short and so incredibly thin that her body can only fit one egg at a time. And it’s a goofy-looking one: At just .08 by .5 inches, six times as long as it is wide, the egg is about the size and shape of long-grain rice, whereas most snake eggs tend to be more spherical.

This is an extreme evolutionary tradeoff. By growing so small, the threadsnake has sacrificed high fecundity, that is, how many young it’s able to produce. This is of course rather risky. We humans having a single child is one thing, since we stick around to dotingly care for it for a long, long time (well, ideally at least). But most reptiles lay their eggs and just take off. Yet here we have a tiny snake that’s been getting along perfectly fine dropping just one egg. Problem is, its life history as a whole and its ecology remain very much mysterious. For all we know the females could actually stick around and guard their hatchling like some species of reptile do. “We know almost nothing about these because they’re so rare,” said Hedges. “There’s only a few specimens that have ever been seen and collected. Nobody’s ever studied them ecologically.”

But we can be sure that there’s a very good reason why the threadsnake got so tiny: shrink rays. Wait, no. Not shrink rays.

Little Big Planet

When an island forms, it’s ripe for conquering. Plants and animals get there any number of ways: swimming, floating on debris after a hurricane, flying, blowing in the wind (spiders can float hundreds of miles by sending out silk that gets caught up in gusts). And when the first creatures arrive, they find a whole lot of open jobs in the ecosystem just asking to be taken, known as niches. And those new jobs aren’t necessarily the ones the critters had back on the mainland. This may have been what happened to the threadsnake. “This species, even though it’s a snake,” said Hedges, “it could be filling a niche of a smaller invertebrate like a centipede or something like that on the mainland.”

God I hope this was a first date. How weird would that be. “Hey, you wanna check out a model of titanoboa, which, at nearly 50 feet long, was the largest snake to ever live?” *silence* “OK, but why are you talking like that?”

Now, some species tend to be rarer on islands than other groups. This is because the journey on debris would be far more difficult for something like a mammal or an amphibian than, say, beetles, which are fantastic at retaining moisture. So it could be that the threadsnake’s ancestors arrived on Barbados, while their typical prey failed to make the journey. Over evolutionary time, the threadsnake adapted to take on different game, and became so specialized that it just may have reached the smallest possible size for a serpent. (By the way, there was once a snake that got to what’s probably the largest possible size. This was titanoboa, which grew to almost 50 feet long and 2,500 pounds, 2 million times heavier than the threadsnake. It pushed the boundaries of what the laws of physics actually allow—gravity was such a drag on the creature that it probably spent the bulk of its time in the water.)

Read more at Wired Science

Mystery of Baleen Whale's Hearing May Be Solved

In what a researcher calls a "grand discovery," the question of how baleen whales hear may have been answered, solving a long-standing mystery.

Baleen whales, the largest animals on Earth at about 65 to 80 feet long, can emit vocalizations at very low frequencies, at wavelengths sometimes longer than the whales themselves. But how they hear, has remained to scientists a bit of a puzzle.

Rather than use more traditional whale-hearing analysis -- relying on anatomic study and sound-playback experiments with whales in controlled environments -- two researchers from San Diego decided to use computational horsepower and 3D software to tackle the problem.

San Diego State University biologist Ted W. Cranford and University of California, San Diego engineer Petr Krysl created a three-dimensional computer model of a baleen whale's head, one that would include the skin, skull, eyes, ears, tongue, brain, muscles, and jaws.

For their test subject, the pair obtained the head of a fin whale that beached in 2003 and then ran it through an X-ray CT scanner.

Once they had the head scan, Cranford and Krysl ran simulations of how sound travels through the whale's brain. To get the detail they needed, they used a technique called finite element modeling, in which the data representing the head parts and skull were separated out into tiny elements by the millions, the relationships between the elements tracked.

Sound can reach a baleen whale's ear bones on its skull in two ways: the sound's pressure waves can go through the animal's soft tissue; or the sounds can vibrate along the skull itself, in a process called "bone induction."

The problem with the soft-tissue, pressure, route, the researchers said, is that it's ineffective when sound waves are longer than the whale's body. But with the bone induction process, those longer waves become amplified as they vibrate in the creature's skull.

The scientists' computer modeling showed that the bone induction process was about four times more sensitive to low-frequency sounds than the soft-tissue, pressure mechanism.

What's more, their modeling predicted that bone induction is 10 times more sensitive to the lowest frequencies used by fin whales (10 Hz-130 Hz).

Read more at Discovery News

Corpse of 200-Year-Old Monk Found in Lotus Position

The amazingly intact remains of a meditating monk have been discovered in the Songinokhairkhan province of Mongolia, according to a report in Mongolia’s Morning News.

The mummified body, which was covered in animal skin, has been sitting in the lotus position for about 200 years.

According to the report, no information is so far available as to where the body was found.

“The only details we learned was that it was covered with a cattle skin,” the newspaper wrote.

Researchers at the Ulaanbaatar National Centre of Forensic Expertise are now analyzing the remains.

According to The Siberian Times, experts are speculating over whether the mummy is a “teacher of famous Lama Dashi-Dorzho Itigilov,” a Buddhist Lama of the Tibetan Buddhist tradition who was born in 1852.

Itigilov also died while meditating in lotus posture and was buried in 1927 in that position, his remains laid to rest in a pine box. When he was exhumed in 1955 and in 1973, astonished monks found the body in near-perfect condition and still sitting upright.

From Discovery News

Netflix Marco Polo Series 'Riddled With Historical Errors'

The big-budget American series "Marco Polo," on the 13th-century Venetian explorer and his years at the court of the Mongol emperor Kublai Khan, is riddled with historical errors, say Mongolian viewers and experts.

Netflix has spent tens of millions of dollars on the show, touted as its answer to HBO's huge hit Game of Thrones. With swashbuckling sword fights, mass battles, intricate costumes and palace plots, the series portrays conflicts and rebellions in the Mongol empire under Kublai Khan, as seen through Marco Polo's eyes.

Kublai, the grandson of the great Mongol conqueror Genghis Khan, was a phenomenal warrior himself, reigning from 1260 to 1294, subjugating swathes of China and establishing the Yuan dynasty of Chinese emperors.

Mongolian viewers were excited to see one of their own being cast as Kublai's brother Ariq Boke and hearing the occasional Mongol phrase, despite most leading roles going to Chinese actors or those of Chinese descent, such as Briton Benedict Wong, who plays Kublai.

But according to Mongolian historians, much of the plot plays fast and loose with the facts.

Batsukh Otgonsereenen, who spent 10 years researching his book The History of Kublai Khan, told AFP: "From a historical standpoint 20 percent of the film was actual history and 80 percent fiction."

The fate of Ariq Boke, who briefly took power following the death of their father but lost the subsequent civil war, was particularly twisted, he said.

"The part where Kublai and Ariq Boke fight to a bloody death in front of their soldiers is completely untrue," he said. "Yes, Ariq did try to seize the throne, but in history Kublai and Ariq resolve their issues."

A concubine-assassin supposedly sent by a minister of the rival Song dynasty to seduce Kublai and kill his queen was another fantasy.

"Mongolian Khans never wed or had concubines that were totally unknown," said Otgonsereenen. "Kublai also did not live in a palace. He lived in his royal ger in Beijing, in a traditional Mongolian manner."

In a press release, Netflix described the series -- shot in Kazakhstan, Malaysia and Italy, rather than Mongolia or China -- as set in a world "replete with exotic martial arts, political skullduggery, spectacular battles and sexual intrigue."

But Otgonsereenen said the creators' research on Kublai seemed "very sloppy."

"I think they tried to show Mongolian history like Game of Thrones with conspiracy, betrayal, blood and sex," he said. "Mongolian youth who watch this series might get the wrong impression of Kublai Khan being quite cruel and perverted."

- Big in the Middle Ages -

Polo -- played by Italy's Lorenzo Richelmy in the show -- was a Venetian merchant who spent more than two decades in central Asia and China with his father and uncle, serving for years as Kublai's minister and envoy.

After his return the story of his journeys, "Book of the Marvels of the World," also known as The Travels of Marco Polo, propelled him to medieval superstardom.

He was not the first European to travel to Asia but became by far the most famous, and his descriptions of the Far East are said to have inspired Christopher Columbus to attempt to travel there himself, only to discover the Americas instead.

But U.S. critics panned the show, with news site vox.com's reviewer writing: "This is a show about Kublai Khan that doesn't realize it's about Kublai Khan because Marco Polo has better name recognition.

"Is it worth watching?" he asked rhetorically. "Eh, not really, no."

The series, released last month, has a 30 percent rating on review aggregator rottentomatoes.com, which describes it as "an all-round disappointment."

Nonetheless a second season has been commissioned.

- Neighborly tensions -

Some Mongolian viewers praise the series, and many welcome the space it gives their remote country on the global small screen.

Orgil Narangerel, who played Genghis Khan in a BBC documentary, said it was more accurate than any previous foreign portrayal of Mongolian culture.

"As a Mongol and an artist, 'Marco Polo' makes me feel like our dreams are coming true," he told AFP. "I watched all 10 episodes in just in one day.”

Read more at Discovery News

New NASA Satellite to Map Earth's Dirt From Orbit

UPDATE: Due to high-altitude winds the scheduled SMAP launch was scrubbed on Thursday morning. The next launch attempt has been postponed 24 hours later, to Friday (Jan. 30) at 9:20 a.m. EST. The following article has been edited to reflect this new scheduled launch attempt.

NASA's next Earth-observing satellite is ready to launch Friday (Jan. 29), and it could vastly improve the way scientists monitor droughts around the world.

Originally scheduled to launch on Thursday, the space agency's Soil Moisture Active Passive satellite (SMAP) is now scheduled to launch from California's Vandenberg Air Force base atop a United Launch Alliance Delta II rocket at 9:20 a.m. EST (6:20 a.m. PST) on Jan. 30, and at the moment, weather is looking good ahead of liftoff.

The SMAP satellite is designed to measure the moisture of Earth's dirt more accurately than ever before, according to NASA. The probe will make a global map of the planet's soil moisture levels every three days. This measurement is important because it can help scientists create more accurate weather models, learn more about drought conditions and even predict floods, NASA officials have said.

"What the soil measurements will do is improve our weather forecasts, improve our assessments of water availability and also address some issues dealing with long-term climate variability and assessments of the impact of human intervention in the global environment," Dara Entekhabi, SMAP science team leader, said during a news conference Tuesday (Jan. 27). "All of these come together and it's the metabolism, how it responds, just like a human body."

You can watch live coverage of the SMAP satellite launch starting at 7 a.m. EST Friday (Jan. 30) on Space.com via NASA TV.

The SMAP probe comes equipped with a huge mesh antenna, expected to be deployed sometime after launch. At nearly 20 feet (6 meters), the antenna is the largest of its kind that NASA has ever flown in space, officials have said. SMAP's antenna is designed to spin at about 14.6 revolutions per minute while mounted to the end of a long arm on the satellite's body.

The satellite is built to measure moisture in the top 2 inches (5 centimeters) of soil from its spot in orbit about 426 miles (685 kilometers) above Earth's surface, completing an orbit once every 98.5 minutes. The satellite's unprecedented soil information could help scientists learn more about how droughts spread and the places where they occur. By knowing the moisture in topsoil ahead of time, it could also help researchers better-predict where floods will happen.

"Soil moisture is a key part of the three cycles that support life on this planet: the water cycle, the energy cycle and the carbon cycle," NASA SMAP program executive Christine Bonniksen, said during the news conference. "These things affect human interest: flood, drought, disease control, weather."

Read more at Discovery News

Could Violent Red Dwarfs Turn Mini-Neptunes into Exo-Earths?

Low-mass, flaring stars are often seen by astrobiologists as the last place to find habitable exoplanets, but new research suggests that these angry little suns could in fact turn lifeless ‘mini-Neptunes’ into potentially habitable ‘exo-Earths.’

M-type red dwarf stars possess two qualities that are usually considered too harsh to nurture habitable exoplanets: extreme tides and violent space weather.

As the star is smaller, its habitable zone is more compact, so any potentially habitable world would have to orbit very close to its star. Orbiting so close would induce extreme tides on this world, likely rendering it barren and sterile.

“This is the reason we have ocean tides on Earth, as tidal forces from both the moon and the sun can tug on the oceans, creating a bulge that we experience as a high tide,” said Rodrigo Luger, of the University of Washington, lead author of a paper published in the journal Astrobiology. “Luckily, on Earth it’s really only the water in the oceans that gets distorted, and only by a few feet. But close-in planets, like those in the habitable zones of M dwarfs, experience much stronger tidal forces.”

These tidal forces would physically warp the planet’s crust, driving extreme tectonic activity and volcanism, possibly triggering a runaway greenhouse effect, vaporizing any surface water. Tidal locking — where one hemisphere continually faces the star — would also be a problem.

M-type red dwarfs are also known to have extreme space weather, and any planet orbiting within the star’s habitable zone would bear the brunt of powerful stellar flares and strong stellar winds. This irradiated environment would ultimately erode any surviving atmosphere away, blowing it into space.

But what’s bad for an Earth-like exoplanet may not be so bad for a mini-Neptune, which sports a thick atmosphere during formation.

Mini-Neptunes would form far from their host stars, “with ice molecules joining with hydrogen and helium gases in great quantity to form icy/rocky cores surrounded by massive gaseous atmospheres,” writes a UW press release.

“They are initially freezing cold, inhospitable worlds,” Luger said. “But planets need not always remain in place. Alongside other processes, tidal forces can induce inward planet migration.”

Inward migration would cause the mini-Neptune to be exposed to the stellar blowtorch and, over millions of years, the mini-Neptune’s atmosphere would be blown away. Once lodged in the star’s habitable zone, the mini-Neptune’s hydrogen-free core may be left behind; objects called “habitable evaporated cores” or HECs.

“Such a planet is likely to have abundant surface water, since its core is rich in water ice,” said Luger. “Once in the habitable zone, this ice can melt and form oceans.”

For these HECs to become anything remotely ‘habitable’, a very delicate balance of atmospheric chemistry and radiation from the star would be needed. But in some models, oxygen-rich atmospheres are possible, incubating liquid water on the rocky surface.

Whether or not such a planet could host any kind of life remains open to debate. One could imagine that if an HEC evolves with a powerful magnetosphere, the worst stellar storms may be deflected. As for the problems with the extreme red dwarf tides, the world may well be tidally locked, where one side of the planet may be inhosptable, but powerful weather systems whip around the planet, creating the most extreme biosphere imaginable where life thrives in isolated regions.

Read more at Discovery News

Medieval Skulls Reveal Long-Term Risk of Brain Injuries

Skull fractures can lead to an early death, even if the victims initially survived the injuries, according to a new study that looked at skulls from three Danish cemeteries with funeral plots dating from the 12th to the 17th centuries.

This is the first time that researchers have used historical skulls to estimate the risk of early death among men who survived skull fractures, experts said. The study showed that these men were 6.2 times more likely to die an early death compared with men living during that time without skull fractures. Today, the risk of dying after getting a traumatic brain injury is about half that, likely because of improvements in modern medicine and social support, according to the researchers.

"Their treatment then would have been pretty much go home, lie down and hope for the best," said study researcher George Milner, a professor of anthropology at Pennsylvania State University. "There was very little that could be done at that time."

Often, epidemiology — the study of disease incidence and prevalence among large populations — is confined to living samples. But the researchers suggest that skull fractures, much like high blood pressure or cholesterol in present-day patients, can be used in historic samples as markers for an increased risk of getting sick or dying.

"What we want to do is to be able to obtain figures or statistics that are comparable to those of today to give us a long-term perspective of pathological conditions of various sorts," Milner said.

The researchers examined skeletons that were exhumed to make room for new building developments in Denmark. In all, the scientists found 236 skulls from men, including 21 individuals who had healed skull fractures.

Too few women had skull fractures, so they were not included in the analysis. The researchers also excluded men who appeared to have died immediately from their skull injuries, based on jagged and sharp fractures seen on the skulls. Healed fractures tend to have rounded edges from remodeled bone, Milner said.

"The vast majority only had one blow" to the head, Milner said. But two skulls had two injuries apiece, including a man with an injury on both sides of his head, and another man with separate injuries on the front and side of his skull.

It's likely that the fractures happened during violence or fighting between people or from work accidents, the researchers said. But it's unclear what ultimately killed the men.

One speculation is that these skull fractures were accompanied by traumatic brain injuries, which could have affected the men's longevity. But it's also possible the fractures and reduced longevity were caused by the same lifestyle traits among the men.

"Was it a lifestyle that caused the trauma that led to early death?" said Jane Buikstra, a professor of bioarchaeology at Arizona State University, who was not involved with the study. Or did the trauma lead "to a biological disability that may have predisposed early death?"

Read more at Discovery News

First Neanderthal-Human 'Love Child' From Israel

The fateful first meeting -- and eventual mating -- between Neanderthals and our species happened in Israel 50,000 to 60,000 years ago, finds a new study.

The key evidence, presented in the journal Nature, is a newly discovered fossilized skull of a Homo sapiens who co-existed with Neanderthals and likely was a human-Neanderthal "love child." To this day, people of European and Asian heritage retain Neanderthal DNA as a result of the ancient encounters.

The partial skull, thought to have been part of a female human, has been named "Manot," after the cave in northern Israel where it was found. A high tech dating method determined that the skull is 55,000 years old.

"Manot clearly shows that Neanderthals and modern human lived side by side in Israel for a long period of time," co-author Israel Hershkovitz of Tel Aviv University told Discovery News. "All recent genetic and archaeological studies predict that the interbreeding event between the Neanderthals and modern humans occurred between 50,000-60,000 years ago, and in the Near East."

Hershkovitz and other Israeli scientists, as well as anthropologists from the University of Vienna and the Max Planck Institute, Leipzig, used a barrage of high tech methods, including computer tomography, to study Manot in detail. They then compared this information with data on hundreds of other early human skulls to note differences and similarities.

"The shape analysis shows very clearly that Manot was a modern human," co-author Gerhard Weber of the University of Vienna said. "It is interesting that the most similar skulls in our sample come from recent Africans on the one hand, and on the other hand from those modern humans that lived in Europe between 20,000-30,000 years ago."

Manot is clearly much older than those Europeans, however, and even pre-dates the first known Homo sapiens in Europe by 10,000 years. This weakens theories that our species and Neanderthals first encountered each other in Europe.

Given the timing as well as Manot's mixture of features, Weber suspects "it could be that Manot is one of the hybrids," meaning part Homo sapiens and part Neanderthal. Other archaic human species lived in Europe and Asia then as well, so additional interbreeding might have taken place between these groups.

Manot is also important because it sheds light on a central migration route taken by our species out of Africa.

At first it was thought that our direct ancestors traveled from Africa via a southern coastal route across the Red Sea to the Arabian Peninsula. Now the researchers suspect that Manot and her Homo sapiens predecessors traveled north from East Africa to the Nubian Desert before continuing on to the Sinai Peninsula and then to Israel.

Weber believes that there were several prehistoric migrations of humans out of Africa and into Europe and Asia beginning well over 100,000 years ago. However, the "successful wave" -- the group that replaced/absorbed all of the others upon arrival -- happened closer to Manot's time.

Chris Stringer of the Natural History Museum supports the theory that Manot could represent the earliest known meeting and mating between our species and Neanderthals.

Stringer told Discovery News that "it is the first modern human from western Asia that is well dated to the estimated time frame of interbreeding between early modern humans and Neanderthals."

He added, "Manot might represent some of the elusive first migrants in the hypothesized out-of-Africa event about 60,000 years ago, a population whose descendants ultimately spread right across Asia and also into Europe."

Read more at Discovery News

Itchy Skin, Diarrhea Evolved to Promote Good Health

From rashes to irritable bowels, people today face certain health challenges because our ancestors evolved the genetic variations associated with these conditions in order to benefit human health, a new study has found.

It's ironic that the genes responsible for certain health problems evolved to help us, but it's a reminder that physical traits are not always all good or bad. There are some cases, as the study published in Molecular Biology and Evolution points out, where the line is not so clear.

"The best example of this is sickle cell anemia," senior author Omer Gokcumen said in a press release.

Gokcumen, a University at Buffalo assistant professor of biological sciences, explained that sickle cell anemia causes red blood cells to take on a curved, crescent-like shape, which leads to anemia (a problem), but also protects against malaria by keeping parasites out of cells (an advantage).

The opposing pressures create a balance where the copy of the gene that causes the sickle cell anemia remains in the population in malaria-ridden geographies.

Gokcumen, lead author Yen-Lung Lin, and their colleagues found that other inherited disorders fall into the problem/advantage pattern of evolution too.

For example, Gokcumen said, "Our research shows that some genetic features associated with psoriasis, Crohn’s disease and other aspects of human health are ancient."

Psoriasis, a chronic skin condition, can cause rashes that itch, burn and sting. Crohn’s disease is an inflammatory bowel disease that can lead to abdominal pain, diarrhea, fatigue, constipation, weight loss and more.

If misery loves company, sufferers can at least take heart knowing that some prehistoric humans, such as Neanderthals and Denisovans, likely suffered from these health problems too.

The researchers found this out after comparing modern human genomes to those of other closely related species, including chimpanzees and the aforementioned archaic humans that lived thousands of years ago.

The scientists identified chunks of DNA that exist in chimpanzees, but were later erased through evolutionary processes. These DNA segments, called deletions, are present in some human genomes, but are missing from others.

The study discovered that certain functionally important deletions that vary among modern humans likely originated in a common ancestor of humans, Neanderthals and Denisovans, possibly dating as far back as a million or more years ago.

The unusually old deletions retain a lot of power. They not only are associated with Crohn's disease and psoriasis, but they also are linked to a person’s ability to respond to a number of drugs, including growth hormone treatments.

"Crohn's disease and psoriasis are damaging, but our findings suggest that there may be something else — some unknown factor now or in the past — that counteracts the danger when you carry genetic features that may increase susceptibility for these conditions," Gokcumen said.

Read more at Discovery News

Fantastically Wrong: The Bizarre Mirages That Once Scared the Bejesus Out of Sailors

The mysterious fata morgana: making people question their sanity since the beginning of time.

Jesuit priests aren’t especially known for their heavy drug use, but it would seem that Father Domenico Giardina was tripping pretty hard on August 14, 1643. Looking out over the sea from Messina, Sicily, Giardina saw “a city all floating in the air, and so measureless and so splendid, so adorned with magnificent buildings, all of which was found on a base of a luminous crystal.” The metropolis suddenly transformed into a garden, and next a forest. And then in a flash it all descended into chaos. Huge armies sprang forth, as did the towns they had laid waste to, before the whole mess disappeared.

Father Giardina, you see, was high on life. The “great and marvelous theater” he had witnessed was the mysterious fata morgana, an incredibly complex mirage that has historically both fascinated and scared the hell out of sailors and landlubbers alike. Whether it be the work of necromancers or fairies or a god, few phenomena have captivated humankind quite so thoroughly as fata morgana.

It was Jesuits like Father Giardina, argues Marina Warner in her brilliant book Phantasmagoria, who made the first “careful” observations of fata morgana, that is, not freaking out about them and instead beginning to apply a dash of science to the matter. The good Father claimed, writes Warner, that the minerals and salts in the region “rise up in hot weather in vapours from the sea to form clouds, which then condense in the cooler upper air to become a mobile specchio, a moving, polyhedrical mirror.” It was wrong, but it actually wasn’t that far off.

Light being refracted downward as it passes from air into a denser material, plexiglass. (Some light is also reflected upward)

At work here is some basic physics. When the sun heats up the atmosphere above the ocean, it creates a gradient of temperatures: Near the surface, it’s still relatively cool because the water is chilling that air, but sitting above that is a layer of warmer air. Now, light doesn’t always travel in a straight line. When it hits a boundary between two layers of the atmosphere that are different temperatures (and therefore different densities), it bends and travels through the new layer at a different angle. This is known as refraction. The change in the light’s angle of travel depends on the difference in density between the two layers.

How does bending light create a mirage? The rest of the effect is caused by how your brain works. When light hits your eyes, your brain assumes it arrived there in a straight path between you and the object reflecting the light. So if light is bent on its way toward you, your brain will think the object is where it would be if the light’s path was straight. This is why when you are looking down on a surface of water, objects under the surface will appear to be in a different spot than they actually are—just ask a spear fisherman…if you happen to know a spear fisherman. The human brain doesn’t automatically account for the refraction. (Interestingly, the brains of some birds like ospreys do correct for the effect so that when they dive headlong into the water after a fish, they are right on target.)

In the case of a fata morgana mirage, light reflecting from a distant object such as a ship is bent downward as it passes through the colder, denser air near the surface of the ocean (or sometimes cold land, particularly ice). But your brain places the object where it would be if the light came to you in a straight path—higher than it actually is. This bending effect can even work with the curvature of the Earth if conditions are just right, which is why some fata morgana images can actually be refracted cities and ships from beyond the horizon.

A superior mirage or fata morgana, left, and an inferior mirage, what you’d see on a hot day on asphalt, right.

The opposite situation is what produces mirages like an oasis of water in the desert. In this case, a hot layer of air just above the surface bends light rays up toward your eyes, causing your brain to perceive things as much lower than they actually are. The desert oasis is actually the sky. This kind of mirage is known as inferior, while the fata morgana, which places objects higher than they actually are, is superior.

But before the Scientific Revolution and all its wonderful advances in physics, mirages were firmly in the realm of mysticism (thank a Frenchman named Pierre de Fermat, by the way, for his pioneering work in decoding inferior mirages right around the same time Father Giardina was making his own observations). Indeed, fata morgana takes its name from Morgan le Fay, the treacherous fairy, enchantress, and half-sister of King Arthur.

Morgan le Fay: fairy, enchantress, sandal enthusiast.

According to Warner, the Normans brought stories of Morgan’s magic to Italy, particularly her penchant for luring sailors to an undersea palace with visions of castles in the air—fata morgana is particularly prevalent in southern Italy’s Strait of Messina, where Father Giardina experienced his own vision. Another Italian version of the legend has Morgan falling in love with a regular fella, granting him immortality, and keeping him in captivity, then putting on shows in the sky when he gets bored with the whole never dying thing.

And long before Arthurian legend, it could have been that sightings of these phenomena gave rise to any number of the “whoa something is appearing in the sky” scenes in antiquity, Warner argues. The Second Book of Maccabees, for example, tells of sky-people coming to the aid of the Jews in their skirmishes with the Romans: “When the battle became fierce, there appeared to the enemy from heaven five resplendent men on horses with golden bridles, and they were leading the Jews.” The ghostly warriors fired arrows and thunderbolts at the rascally Romans, “so that, confused and blinded, they were thrown into disorder and cut to pieces.”

Fata morgana’s most famous offspring, though, is the legend of the Flying Dutchman, a ghost ship said to sail aimlessly around the high seas. The tale was first popularized in a story called “Vanderdecken’s Message Home” from 1821, which told of a boat from Amsterdam that haunts the Cape of Good Hope, trying to hand off letters from its dead crew to the vessels of the living (uh, no thanks, the sailors would say, you can deliver your own damn mail). Warner connects this to fata morgana showing a ship from beyond the horizon: The mirage vessel could suddenly disappear with no explanation, and there you have your legend.

Read more at Wired Science

Earliest Known Snakes Slithered Around Dinosaurs

The earliest known snakes slithered around dinosaurs and likely ate the behemoth's eggs and young during the heart of the Middle Jurassic when dinosaurs were becoming the dominant predators on land.

Four newly discovered ancient snake fossils date the reptiles to between 140 and 167 million years ago, according to a new study, published in the journal Nature Communications. The earliest date is nearly 70 million years older than the previous record of ancient snake fossils.

Lead author Michael Caldwell explained to Discovery News that it is "very likely that snakes ate young dinosaurs or preyed upon their eggs."

"A very good example comes from the Late Cretaceous of India where a well preserved snake was found in a sauropod dinosaur nest with embryos of the dinosaur still in the egg," added Caldwell, who is the president of the Canadian Society of Vertebrate Paleontology and is chair of the University of Alberta's Department of Biological Sciences.

The oldest known snake, Eophis underwoodi, was unearthed in Southern England. It was small, although it could have been a juvenile when it died, and lived in a swamp or marsh environment 167 million years ago.

The second oldest is Diablophis gilmorei, which lived in a river or swamp area in what is now Colorado 155 million years ago. The largest snake of the quartet, Portugalophis lignites, is the same age, but lived in an ancient swamp in what is now Portugal. The youngest snake, Parviraptor estesi, dates to 140 million years ago and hailed from a lake region full of snails and algae in Western Europe.

"All of these snakes were living in or near water sources, at least close enough that when they died, their remains were preserved in rocks deposited in water," Caldwell said.

He added that, in addition to dinosaurs, the ancient snakes coexisted with pterodactyls, early mammals, crocodiles, lizards, amphibians, many kinds of fishes, and numerous other types of animals. Caldwell thinks that snakes preyed upon many of these species, and vice versa.

The prior fossil record suggested that snakes suddenly emerged and went through an explosive radiation around 100 million years ago. Now it's known that the process happened gradually, with snakes evolving their characteristic limbless, slithery bodies over a lengthy period of time.

The consensus is that snakes evolved from an as-of-yet unknown lizard ancestor, losing their forelimbs, shoulder girdles and breastbones along the way. It is even possible that the earliest snakes still retained short bodies and large legs from their lizard ancestors. Caldwell said that Eophis and its ancestors must have evolved as snakes much earlier than the Middle Jurassic, so even older, more primitive snakes are theorized to have existed.

There is also a chicken and egg question: Which came first, the snake's loss of limbs or its characteristic skull? Caldwell says it is possible that the skull emerged first.

He explained that, compared to the skulls of non-snake lizards, "the snake skull is more mobile as a result of reduced sutures and bony contacts, and ‘gets out of the way,' so to speak, when a snake eats large prey."

"As it appears that this feature evolved early on in snake evolution," he continued, "it looks as though some of the success of the snake feeding strategy is tightly linked to the early evolution of the skull within the group."

Read more at Discovery News

New Tattoos Found on Oetzi the Iceman

New scans have revealed a total of 61 tattoos on the 5,300-year-old mummified body of Ötzi the Iceman, reigniting the debate on whether the inkings were a form of acupuncture that predates the first recorded use of the practice in China by 2,000 years.

A number of tattoos were noticed on the Iceman ever since his discovery in 1991 in a melting glacier in the Ötztal Alps (hence the name). However, the markings, produced by fine incisions into which charcoal was rubbed, were not easily identifiable because of the dark color of the mummy’s skin.

To accurately determine the exact number and location of the tattoos on the Iceman's body, Marco Samadelli and colleagues from the South Tyrol Museum of Archaeology in Italy used innovative non-invasive multispectral photographic imaging techniques able to capture a range of wavelengths, from IR to UV.

The researchers slightly thawed the body in order to eliminate the ice layer wrapping the surface of the Iceman and photographed the body systematically from all directions.

"By covering a range including non-visible and visible light, all possible tattoos could be detected," Samadelli and colleagues wrote in the Journal of Cultural Heritage.

It emerged the mummified body was marked with 61 tattoos divided into 19 groups across various body parts.

"It is an extraordinary result. Finally, we have been able to clarify many doubts on the existence of these tattoos," Samadelli told Discovery News.

The majority consisted of linear markings running parallel to each other, between 2 mm (0.07 inches) and 8 mm (0.3 inches) apart. The marks were between 1 mm (0.03 inches) and 3 mm (0.1 inches) thick and between 7 mm (0.2 inches) and 40 mm (1.5 inches) long.

In two locations, on the knee of the right leg and on the ankle of the left foot, the lines formed a perpendicular cross.

The highest concentration of drawings was found in the lower section of the legs, while the longest tattoos were detected around the wrist of the left hand. Visible tattoos, which have been documented before, lay on the back of the lumbar region.

The new imaging technique also allowed the researchers to detect a previously unrecognized group of tattoos.

"It is located in the right lower thoracic region, showing four parallel lines of length varying from 20 mm (0.7 inches) to 25 mm (0.9 inches)," Samadelli and colleagues explained.

"This is of particular interest, as this represents the first tattoo that was detected on the Iceman’s frontal part of the torso," they added.

It was previously believed the tattoos were made as a sort of treatment or diagnosis of health problems, in particular lower back pain and degenerative joint disease of his knees, ankle and wrist. Other studies associated the marking to a primitive form of acupuncture as they were mainly found along acupuncture meridians used to treat back pain.

"The newly identified tattoo at the chest of the Iceman seems to contradict the theory, that they were related to lower back pain and degenerative joint diseases, as this mark is not located close to a joint," said the researchers.

However, they noted the Iceman also suffered from conditions that could have also caused pain in the chest area, such as gallbladder stones, worms in his colon, and atherosclerosis.

"Therefore, it cannot be ruled out that the Iceman's tattoos were indeed applied as a therapeutic treatment," they concluded.

Read more at Discovery News

Melting, Not Meteorite, Caused Crater in Antarctica

A mysterious crater that was discovered in East Antarctica last month likely formed beneath a leaky meltwater lake, rather than because of a meteorite impact, researchers now think.

The ring of sunken ice, nearly 2 miles (3 kilometers) wide, was spotted a few days before Christmas on the Roi Baudoin Ice Shelf in East Antarctica, north of Belgium's Princess Elisabeth research station.

At first, German researchers suspected a meteorite blasted out the crater, because a space rock exploded over East Antarctica in 2004.

However, after the find was announced in early January, scientists gathered on social media and immediately shot down the meteorite hunch. "It was like a virtual coffee table conversation," Olaf Eisen, a glaciologist at the Alfred Wegener Institute in Germany, said of the online discussion.

"Real coffee table conversations are difficult for glaciologists, because there aren't that many of us and we're spread all over the world. In this case, social media was the solution," he told Live Science.

Even though only one tantalizing photo of the crater was published, Antarctica experts rapidly hunted down the circular structure on satellite images. The puzzler drew luminaries such as Doug MacAyeal, president of the International Glaciological Society, and Ted Scambos, a leading expert on Antarctic ice shelves.

Within days, scientists on Facebook and Twitter had settled on an alternative origin. (The Alfred Wegener Institute recently provided clearer pictures of the icy ring.)

Glaciologists who pored over the newly discovered feature think the crater resembles an ice doline — a sinkhole-type pit that appears when meltwater lakes suddenly drain from their bottoms.

The collapsed circles of ice commonly appear in West Antarctica and Greenland, where prodigious surface melting results in scores of lakes, but ice dolines aren't widely known even among glaciologists.

"Doline is a pretty obscure term," said Allen Pope, a glaciologist at the National Snow and Ice Data Center in Boulder, Colorado, and the University of Washington's Polar Science Center.

Historical satellite images uncovered by Pope and others suggest the ice doline crater has been traveling with the ice shelf since the 1990s. (An ice shelf is a thick, floating slab of ice anchored to glaciers or ice sheets on land.) And it's not alone — several small craters pit the surrounding ice, which suggests widespread surface melting.

The hypothesis is appealing to the scientists who found the structure, even though none had heard of ice dolines before, said Graeme Eagles, one of the German geophysicists who was at Princess Elisabeth research station during the discovery.

"One of the things I learned as a geology student was that the vast majority of circular structures in rocks are attributable to processes other than meteorite impacts," he said in the station's research blog.

For researchers, the ice dolines may prove more exciting than a meteorite crater because now they must ponder how the meltwater lakes formed.

“It is still a spectacular discovery, and now it needs an explanation," said Peter Kuipers Munneke, a glaciologist at Swansea University in the United Kingdom.

Cold and dry East Antarctica isn't known for extensive surface melting, such as the lakes typically seen on West Antarctica's ice shelves. Yet the scattered ice dolines suggest there is enough meltwater to fill several lakes, Munneke said. "Maybe that's the biggest surprise," he told Live Science.

The first clear answers could arrive later this year. Alfred Wegener Institute scientists collected radar data at the crater in December, which could determine whether the structure is truly an ice doline.

Read more at Discovery News

Big-Toothed Fossil May Be Primitive New Human

The first known prehistoric human from Taiwan has been identified and may represent an entirely new species that lived as recently as 10,000 years ago, according to a new study.

The newly discovered big-toothed human, "Penghu 1," strengthens the growing body of evidence that Homo sapiens was not the only species from our genus living in Europe and Asia between 200,000 and 10,000 years ago.

Anthropologists have learned that Neanderthals, Denisovans and Homo floresiensis (a.k.a. the "Hobbit Human") lived in Europe and Asia within that time frame. Penghu 1, which is described in the latest issue of Nature Communications, adds to that already impressive list and might have co-existed -- and even interbred -- with our species.

"The available evidence at least does not exclude the possibility that they survived until the appearance of Homo sapiens in the region, and it is tempting to speculate about their possible contact," co-author Yousuke Kaifu, who is an associate professor in the Department of Biological Sciences at The University of Tokyo, told Discovery News.

Kaifu, lead author Chun-Hsiang Chang, and their team studied the remains of the new human, which is represented by a jawbone with big teeth still in it. Chang explained that fishermen dredged up the jawbone off the coast of Taiwan in Penghu Channel. The fishermen sold it to a local antique shop, where collector Kun-Yu Tsai purchased it. Tsai donated his collection to the National Museum of Natural Science in Taiwan, where Chang works in the Department of Geology.

Chang and his team recognized the importance of Penghu 1, which they theorize could represent a new human species or a regional group of Homo erectus, a.k.a. "Upright Man."

"Penghu 1 is a national treasure in Taiwan and is well preserved at my museum with high security," Chang said.

He and his colleagues believe that, due to its size, the jawbone came from an adult individual and possibly a senior, "because its teeth are worn severely," Chang said.

The jawbone's size further reveals that Penghu 1 was not a dwarf, unlike tiny Homo floresiensis, which lived on the island of Flores, Indonesia, where other animals were also smaller than usual.

Penghu 1 instead lived on what was then mainland Asia in an ecosystem that included many other animals.

"The associated faunal remains suggest that the area was a relatively open, wet woodland," Kaifu said. "This is because of the presence of large-bodied mammals, such as elephants (Stegodon), horses and bear, but the fauna also included animals that prefer marshlands in a hot and humid climate, such as water buffaloes."

With such natural resources, it's not hard to imagine why archaic humans were attracted to the site. While Penghu 1's precise identity remains a mystery for now, one thing is for certain: this big-toothed human was not a member of our species.

"This jaw is clearly not from a modern human and the proposal that it may belong to an ancestor related to, or a descendant of, Homo erectus is a reasonable one," Bernard Wood of George Washington University's Center for the Advanced Study of Human Paleobiology, told Discovery News.

Read more at Discovery News

Kepler Discovers Solar System's Ancient 'Twin'

Astronomers have found a star system that bears striking resemblance to our inner solar system. It’s a sun-like star that plays host to a system of five small exoplanets — from the size of Mercury to the size of Venus.

But there’s something very alien about this compact ‘solar system’; it formed when the universe was only 20 percent the age it is now, making making it the most ancient star system playing host to terrestrial sized worlds discovered to date.

An international collaboration of astronomers that studied NASA’s Kepler Space Telescope's observations over a period of four years, quickly realized that Kepler-444 formed around 11.2 billion years ago.

Though Kepler-444 may be likened to an ancient version of our solar system, the worlds it contains are not thought to be habitable and the planets that astronomers have identified certainly do not resemble Earth. They orbit well inside the star’s habitable zone at a distance only 10 percent the distance that the Earth orbits the sun.

“This system shows that planet formation could take place under very different conditions from the ones in which our solar system was formed and has implications for estimating the total number of planets in our galaxy, and other galaxies,” said co-investigator Sarbani Basu of Yale University.

Kepler detected the family of 5 rocky worlds using the transit method — the exoplanets orbited in front of their host star, causing its light to dim slightly. The worlds’ physical sizes and orbital characteristics could therefore be determined.

But gauging the old age of the star (and therefore the age of the entire star system) required the researchers to use the method of asteroseismology to detect the star’s natural resonances caused by sound waves trapped within the stellar interior. The resonances cause slight variations in the star’s brightness that was then used to measure the star’s size, mass and age.

“There are far-reaching implications for this discovery,” said lead author Tiago Campante of the University of Birmingham, U.K. “We now know that Earth-sized planets have formed throughout most of the universe’s 13.8-billion-year history, which could provide scope for the existence of ancient life in the galaxy.”

Read more at Discovery News

Gigantic ring system around J1407b much larger, heavier than Saturn's

Astronomers at the Leiden Observatory, The Netherlands, and the University of Rochester, USA, have discovered that the ring system that they see eclipse the very young Sun-like star J1407 is of enormous proportions, much larger and heavier than the ring system of Saturn. The ring system -- the first of its kind to be found outside our solar system -- was discovered in 2012 by a team led by Rochester's Eric Mamajek.

A new analysis of the data, led by Leiden's Matthew Kenworthy, shows that the ring system consists of over 30 rings, each of them tens of millions of kilometers in diameter. Furthermore, they found gaps in the rings, which indicate that satellites ("exomoons") may have formed. The result has been accepted for publication in the Astrophysical Journal.

"The details that we see in the light curve are incredible. The eclipse lasted for several weeks, but you see rapid changes on time scales of tens of minutes as a result of fine structures in the rings," says Kenworthy. "The star is much too far away to observe the rings directly, but we could make a detailed model based on the rapid brightness variations in the star light passing through the ring system. If we could replace Saturn's rings with the rings around J1407b, they would be easily visible at night and be many times larger than the full moon."

"This planet is much larger than Jupiter or Saturn, and its ring system is roughly 200 times larger than Saturn's rings are today," said co-author Mamajek, professor of physics and astronomy at the University of Rochester. "You could think of it as kind of a super Saturn."

The astronomers analyzed data from the SuperWASP project -- a survey that is designed to detect gas giants that move in front of their parent star. In 2012, Mamajek and colleagues at the University of Rochester reported the discovery of the young star J1407 and the unusual eclipses, and proposed that they were caused by a moon-forming disk around a young giant planet or brown dwarf.

In a third, more recent study also led by Kenworthy, adaptive optics and Doppler spectroscopy were used to estimate the mass of the ringed object. Their conclusions based on these and previous papers on the intriguing system J1407 is that the companion is likely to be a giant planet -- not yet seen -- with a gigantic ring system responsible for the repeated dimming of J1407's light.

The light curve tells astronomers that the diameter of the ring system is nearly 120 million kilometers, more than two hundred times as large as the rings of Saturn. The ring system likely contains roughly an Earth's worth of mass in light-obscuring dust particles.

Mamajek puts into context how much material is contained in these disks and rings. "If you were to grind up the four large Galilean moons of Jupiter into dust and ice and spread out the material over their orbits in a ring around Jupiter, the ring would be so opaque to light that a distant observer that saw the ring pass in front of the sun would see a very deep, multi-day eclipse," Mamajek says. "In the case of J1407, we see the rings blocking as much as 95 percent of the light of this young Sun-like star for days, so there is a lot of material there that could then form satellites."

In the data the astronomers found at least one clean gap in the ring structure, which is more clearly defined in the new model. "One obvious explanation is that a satellite formed and carved out this gap," says Kenworthy. "The mass of the satellite could be between that of Earth and Mars. The satellite would have an orbital period of approximately two years around J1407b."

Astronomers expect that the rings will become thinner in the next several million years and eventually disappear as satellites form from the material in the disks.

"The planetary science community has theorized for decades that planets like Jupiter and Saturn would have had, at an early stage, disks around them that then led to the formation of satellites," Mamajek explains. "However, until we discovered this object in 2012, no-one had seen such a ring system. This is the first snapshot of satellite formation on million-kilometer scales around a substellar object."

Astronomers estimate that the ringed companion J1407b has an orbital period roughly a decade in length. The mass of J1407b has been difficult to constrain, but it is most likely in the range of about 10 to 40 Jupiter masses.

Read more at Science Daily

Possible therapeutic target for common, but mysterious brain blood vessel disorder

Tens of millions of people around the world have abnormal, leak-prone sproutings of blood vessels in the brain called cerebral cavernous malformations (CCMs). These abnormal growths can lead to seizures, strokes, hemorrhages, and other serious conditions, yet their precise molecular cause has never been determined. Now, cardiovascular scientists at the Perelman School of Medicine at the University of Pennsylvania have studied this pathway in heart development to discover an important set of molecular signals, triggered by CCM-linked gene defects, that potentially could be targeted to treat the disorder.

"We hope that these findings will lead to a better understanding of the origins of CCM, and thus to treatment possibilities," says Mark L. Kahn, MD, a professor of Cardiovascular Medicine, and senior author of the new study, published in Developmental Cell.

Although CCM has a relatively high prevalence of 1 in 200 people worldwide, it typically goes undiagnosed until symptoms arise and can only be treated by brain surgery.

Research on CCM has been slowed by the difficulty of recreating the disease in lab animals. About 20 percent of CCM patients have a highly aggressive, inherited form of the disorder that is caused by inactivating one of three genes, whose protein products normally work together in a complex. But knockout mice bred without a full set of those genes don't mature to have CCMs in their brains--they die in the womb, having failed to develop a working vascular system.

"Those animals die so early in their development that you just don't get enough information about what the genes normally should be doing," Kahn says.

Studies by Kahn's lab and others have shown that CCM gene knockouts remain lethal to fetal mice even when they are limited to the endothelial cells that line blood vessels and the heart.

In the new study, Kahn and colleagues used advanced techniques to restrict CCM gene disruption to the endothelial cells of the developing heart, leaving the mouse vascular system to develop otherwise normally.

The resulting mice still died before birth, this time from a failure of normal heart development, which is not seen in human CCM patients. But they survived in the womb about a week longer than standard CCM knockout mice. That allowed Kahn's team to learn more about the effects of the gene disruptions, and ultimately to find a previously unknown CCM-related signaling pathway.

An initial clue was that the mice developed an abnormally thin layer of heart muscle. A substance known as "cardiac jelly" that should separate the developing heart muscle from the heart endothelium in healthy mice was severely reduced. Analyses of gene expression changes revealed that the CCM-disrupted heart endothelial cells were overproducing protease enzymes that degrade cardiac jelly. Suppressing the activity of the protease genes largely prevented the heart defects.

Kahn's team traced the triggers of the protease gene overactivity back to a signaling protein called MEKK3, which helps drive cell growth and survival and has been implicated in cancers. Reducing MEKK3 activity shut down the jelly-degrading protease genes and mostly prevented the heart defects. Experiments also showed that MEKK3 bound to the CCM-complex proteins, whose absence causes familial CCM disease.

More than a decade ago, other researchers noted that MEKK3 somehow associated with one of the CCM-complex proteins. "That observation didn't really lead anywhere because at the time our understanding of the CCM pathway was minimal," says Kahn. Now it appears that, at least in the endothelial cells of the developing heart, CCM proteins normally bind MEKK3, and when they are absent, MEKK3 becomes abnormally--and harmfully--active.

Read more at Scince Daily

Largest-ever autism genome study finds most siblings have different autism-risk genes

The largest-ever autism genome study, funded by Autism Speaks, reveals that the disorder's genetic underpinnings are even more complex than previously thought: Most siblings who have autism spectrum disorder (ASD) have different autism-linked genes.

Led by the director of the Autism Speaks MSSNG project (pronounced "missing"), the report made the cover of today's Nature Medicine.

Simultaneous with publication, the study's data became part of the historic first upload of approximately 1,000 autism genomes to the Autism Speaks MSSNG portal in Google Cloud Platform. Autism Speaks is making the de-identified data openly available for global research in order to speed understanding of autism and the development of individualized treatments.

"This is a historic day," says study leader Stephen Scherer, "as it marks the first time whole genome sequences for autism will be available for research on the MSSNG open-science database. This is an exemplar for a future when open-access genomics will lead to personalized treatments for many developmental and medical disorders." In addition to leading Autism Speaks' MSSNG program, Dr. Scherer directs the Centre for Applied Genomics at Toronto's Hospital for Sick Children and the McLaughlin Centre at the University of Toronto.

"By using the cloud to make data like this openly accessible to researchers around the world, we're breaking down barriers in a way never done before," says Robert Ring, chief science officer of Autism Speaks and co-author on the Nature Medicine paper. "As always, our goal at Autism Speaks is to accelerate scientific discovery that will ultimately improve the lives of individuals with autism at home and around the world."

In total, the MSSNG project aims to make at least 10,000 autism genomes available for research, along with a "tool box" of state-of-the-art tools to aide analysis.

Autism's Surprising Diversity

In the new study, Dr. Scherer's team sequenced 340 whole genomes from 85 families, each with two children affected by autism. The majority of siblings (69 percent) had little to no overlap in the gene variations known to contribute to autism. They found that the sibling pairs shared the same autism-associated gene changes less than one third of the time (31 percent).

The findings challenge long-held presumptions. Because autism often runs in families, experts had assumed that siblings with the disorder were inheriting the same autism-predisposing genes from their parents. It now appears this may not be true.

"We knew that there were many differences in autism, but our recent findings firmly nail that down," Dr. Scherer says. "We believe that each child with autism is like a snowflake -- unique from the other."

Read more at Science Daily