Mar 30, 2013

Shroud of Turin to be Broadcast Live

The Shroud of Turin, the controversial piece of 14x4 foot linen that some believe to be the burial cloth of Jesus Christ, is to be shown on television for the first time in 40 years on Easter Saturday.

Authorized by Benedict XVI in one of his last acts as Pope, the 90-minute display will be broadcast worldwide at 12 noon (EDT) on the Italian RAI 1 state TV show "A sua Immagine" (In His Image).

The event marks the 40th anniversary of the shroud's first appearance on TV on November 23, 1973. At that time, the display was ordered by Pope Paul VI.

Three hundred ill people will be allowed to witness the event live in Turin Cathedral. The bulletproof, climate-controlled glass case where the relic is kept will be opened, and the linen lifted to be filmed.

Meanwhile, TV watchers will listen to a brief introduction by Pope Francis.

"It will be a message of intense spiritual scope, charged with positivity, which will help hope never to be lost," the Archbishop of Turin, Cesare Nosiglia, was quoted as saying.

The first documented reference of the shroud dates to 1357, when the cloth was displayed in a church in Lirey, France. But scientific interest began much later, in 1898, when the linen was photographed by the lawyer Secondo Pia.

The negatives revealed the image of a bearded man with pierced wrists and feet and a bloodstained head.

In 1988, the Vatican authorized carbon-14 dating. The result was disappointing for believers. Three reputable laboratories in Oxford, Zurich and Tucson, Ariz., concluded that the linen was a medieval fake dating from 1260 to 1390, and not the burial cloth wrapped around the body of Christ.

Although the Catholic Church has remained agnostic on the authenticity of the shroud, making no official pronouncements, several shroud scholars, known as sindonologists, argued that no medieval forger could either have produced such an accurate fake or anticipated the invention of photography.

Speculation about the linen cloth, as well as debates over the validity of the carbon-14 tests, continues.

On the eve of the television display, a new study is claiming that the shroud is far older, dating to between 280 B.C. and 220 A.D.

Detailing their findings in a new book, "The Mystery of the Shroud," Giulio Fanti, associate professor of mechanical and thermal measurement at Padua University, and journalist Saverio Gaeta, argue that chemical and mechanical single fiber tests place the relic within Christ's lifetime, with a margin of error of 250 years.

Moreover, "mineralogical investigations on dusts vacuumed from the shroud, revealed traces of limestone and clay minerals showing high iron content that is consistent with dust present in Palestine," Fanti said.

Displayed for six weeks at Turin Cathedral in 2010, the shroud won't go on public view again until 2025, making the television display a unique opportunity to believers.

And if going on TV is not enough, a digital opportunity is offered to investigate the controversial relic.

A Shroud 2.0 app, available for Apple's iPad/iPhone (soon for Android too), allows to zoom incredibly high-definition details of the linen.

Produced by Haltadefinizione, a company which specializes in art photography, the app originates from a 2008 project approved by Vatican officials.

Read more at Discovery News

Billionaire Plans Park of Giant Dinosaurs

An eccentric Australian mining magnate who is building a replica of the ill-fated Titanic has unveiled his latest scheme -- a park of giant robotic dinosaurs.

Clive Palmer, who last month in New York launched an ambitious plan to build and sail the "Titanic II", said he had ordered more than 100 life-size dinosaur robots from China to populate his north Australian resort.

"We'll have the world's biggest dinosaur exhibit, with 165 animatronic dinosaurs," Palmer said.

He already has two of the towering creatures -- named Jeff and Bones -- on display at his Palmer Coolum Resort on the Sunshine coast north of Brisbane and boasted that the public "haven't seen anything yet."

The robots, some of which measure up to 7 meters tall and weigh in excess of 1.2 tons, will move their tails and chests and blink their eyes. They are expected to arrive by the end of April.

A larger-than-life character who has made a fortune in mining, Palmer said recently that he was funding the Titanic II because "I want to spend the money I've got before I die."

From Discovery News

Mar 29, 2013

Teachers' Gestures Boost Math Learning

Students perform better when their instructors use hand gestures -- a simple teaching tool that could yield benefits in higher-level math such as algebra.

A study published in Child Development, the top-ranked educational psychology journal, provides some of the strongest evidence yet that gesturing may have a unique effect on learning. Teachers in the United States tend to use gestures less than teachers in other countries.

"Gesturing can be a very beneficial tool that is completely free and easily employed in classrooms," said Kimberly Fenn, study co-author and assistant professor of psychology at Michigan State University. "And I think it can have long-lasting effects."

Fenn and Ryan Duffy of MSU and Susan Cook of the University of Iowa conducted an experiment with 184 second-, third- and fourth-graders in Michigan elementary classrooms.

Half ofthe students were shown videos of an instructor teaching math problems using only speech. The others were shown videos of the instructor teaching the same problems using both speech and gestures.

The problem involved mathematical equivalence (i.e., 4+5+7=__+7), which is known to be critical to later algebraic learning. In the speech-only videos, the instructor simply explains the problem. In the other videos, the instructor uses two hand gestures while speaking, using different hands to refer to the two sides of the equation.

Students who learned from the gesture videos performed better on a test given immediately afterward than those who learned from the speech-only video.

Another test was given 24 hours later, and the gesture students actually showed improvement in their performance while the speech-only students did not.

While previous research has shown the benefits of gestures in a one-on-one tutoring-style environment, the new study is the first to test the role of gestures in equivalence learning in a regular classroom.

The study also is the first to show that gestures can help students transfer learning to new contexts -- such as transferring the knowledge learned in an addition-based equation to a multiplication-based equation.

Fenn noted that U.S. students lag behind those in many other Western countries in math and have a particularly hard time mastering equivalence problems in early grades.

Read more at Science Daily

Gene Discovery May Yield Lettuce That Will Sprout in Hot Weather

A team of researchers, led by a University of California, Davis, plant scientist, has identified a lettuce gene and related enzyme that put the brakes on germination during hot weather -- a discovery that could lead to lettuces that can sprout year-round, even at high temperatures.

The study also included researchers from Arcadia Biosciences and Acharya N.G. Ranga Agricultural University, India.

The finding is particularly important to the nearly $2 billion lettuce industries of California and Arizona, which together produce more than 90 percent of the nation's lettuce. The study results appear online in the journal The Plant Cell.

"Discovery of the genes will enable plant breeders to develop lettuce varieties that can better germinate and grow to maturity under high temperatures," said the study's lead author Kent Bradford, a professor of plant sciences and director of the UC Davis Seed Biotechnology Center.

"And because this mechanism that inhibits hot-weather germination in lettuce seeds appears to be quite common in many plant species, we suspect that other crops also could be modified to improve their germination," he said. "This could be increasingly important as global temperatures are predicted to rise."

Most lettuce varieties flower in spring or early summer and then drop their seeds -- a trait that is likely linked to their origin in the Mediterranean region, which, like California, characteristically has dry summers. Scientists have observed for years that a built-in dormancy mechanism seems to prevent lettuce seeds from germinating under conditions that would be too hot and dry to sustain growth. While this naturally occurring inhibition works well in the wild, it is an obstacle to commercial lettuce production.

In the California and Arizona lettuce industries, lettuce seeds are planted somewhere every day of the year -- even in September in the Imperial Valley of California and near Yuma, Ariz., where fall temperatures frequently reach 110 degrees.

In order to jump-start seed germination for a winter crop in these hot climates, lettuce growers have turned to cooling the soil with sprinkler irrigation or priming the seeds to germinate by pre-soaking them at cool temperatures and re-drying them before planting -- methods that are expensive and not always successful.

In the new study, researchers turned to lettuce genetics to better understand the temperature-related mechanisms governing seed germination. They identified a region of chromosome six in a wild ancestor of commercial lettuce varieties that enables seeds to germinate in warm temperatures. When that chromosome region was crossed into cultivated lettuce varieties, those varieties gained the ability to germinate in warm temperatures.

Further genetic mapping studies zeroed in on a specific gene that governs production of a plant hormone called abscisic acid -- known to inhibit seed germination. The newly identified gene "turns on" in most lettuce seeds when the seed is exposed to moisture at warm temperatures, increasing production of abscisic acid. In the wild ancestor that the researchers were studying, however, this gene does not turn on at high temperatures. As a result, abscisic acid is not produced and the seeds can still germinate.

The researchers then demonstrated that they could either "silence" or mutate the germination-inhibiting gene in cultivated lettuce varieties, thus enabling those varieties to germinate and grow even in high temperatures.

Read more at Scince Daily

Pluto's Gate Uncovered in Turkey

A “gate to hell” has emerged from ruins in southwestern Turkey, Italian archaeologists have announced.

Known as Pluto's Gate -- Ploutonion in Greek, Plutonium in Latin -- the cave was celebrated as the portal to the underworld in Greco-Roman mythology and tradition.

Historic sources located the site in the ancient Phrygian city of Hierapolis, now called Pamukkale, and described the opening as filled with lethal mephitic vapors.

“This space is full of a vapor so misty and dense that one can scarcely see the ground. Any animal that passes inside meets instant death,” the Greek geographer Strabo (64/63 BC -- about 24 AD) wrote.

“I threw in sparrows and they immediately breathed their last and fell,” he added.

Announced this month at a conference on Italian archaeology in Istanbul, Turkey, the finding was made by a team led by Francesco D'Andria, professor of classic archaeology at the University of Salento.

D'Andria has conducted extensive archaeological research at the World Heritage Site of Hierapolis. Two years ago he claimed to discover there the tomb of Saint Philip, one of the 12 apostles of Jesus Christ.

Founded around 190 B.C. by Eumenes II, King of Pergamum (197 B.C.-159 B.C.), Hierapolis was given over to Rome in 133 B.C.

The Hellenistic city grew into a flourishing Roman city, with temples, a theater and popular sacred hot springs, believed to have healing properties.

“We found the Plutonium by reconstructing the route of a thermal spring. Indeed, Pamukkale' springs, which produce the famous white travertine terraces originate from this cave,” D'Andria told Discovery News.

Featuring a vast array of abandoned broken ruins, possibly the result of earthquakes, the site revealed more ruins once it was excavated. The archaeologists found Ionic semi columns and, on top of them, an inscription with a dedication to the deities of the underworld -- Pluto and Kore.

D'Andria also found the remains of a temple, a pool and a series of steps placed above the cave -- all matching the descriptions of the site in ancient sources.

“People could watch the sacred rites from these steps, but they could not get to the area near the opening. Only the priests could stand in front of the portal,” D'Andria said.

According to the archaeologist, there was a sort of touristic organization at the site. Small birds were given to pilgrims to test the deadly effects of the cave, while hallucinated priests sacrificed bulls to Pluto.

The ceremony included leading the animals into the cave, and dragging them out dead.

“We could see the cave's lethal properties during the excavation. Several birds died as they tried to get close to the warm opening, instantly killed by the carbon dioxide fumes,” D'Andria said.

Only the eunuchs of Cybele, an ancient fertility goddess, were able to enter the hell gate without any apparent damage.

“They hold their breath as much as they can,” Strabo wrote, adding that their immunity could have been due to their "menomation," “divine providence” or “certain physical powers that are antidotes against the vapor.”

According to D'Andria, the site was a famous destination for rites of incubation. Pilgrims took the waters in the pool near the temple, slept not too far from the cave and received visions and prophecies, in a sort of oracle of Delphi effect. Indeed, the fumes coming from the depths of Hierapoli's phreatic groundwater produced hallucinations.

“This is an exceptional discovery as it confirms and clarifies the information we have from the ancient literary and historic sources,” Alister Filippini, a researcher in Roman history at the Universities of Palermo, Italy, and Cologne, Germany, told Discovery News.

Read more at Discovery News

Volcanic Lightning: How does it work?!

The fusion of flash with ash! Say the words aloud, together, and it sounds impossible – the kind of thing a six-year-old might think up. And yet, volcanic lightning is very real. But how does it happen?

Few phenomena can compete with the raw beauty and devastating power of a raging thunderstorm, save for a particularly violent volcanic eruption. But when these two forces of nature collide, the resulting spectacle can be so sublime as to defy reason.

The photograph above offers some important insights into the formation and study of volcanic lightning. It was taken late last month by German photographer Martin Rietze, on a visit to Japan's Sakurajima volcano. Only very big eruptions, he tells us via email, can generate major thunderbolts like the ones seen above.

Smaller eruptions tend to be accompanied by more diminutive storms, which can be difficult to spot through thick clouds of ash. What's more, lightning activity is highest during the beginning stages of an eruption, making it all the more challenging to capture on film. Photographing a big volcanic event at any stage is hard enough as it is; if you're not nearby when it happens, says Rietze, "you will always arrive too late."

It turns out the same things that make volcanic lightning hard to photograph also make it difficult to study. The first organized attempt at scientific observation was made during Iceland's Surtsey eruption in 1963 (pictured here). The investigation was later recounted in a May 1965 issue of Science:

"Measurements of atmospheric electricity and visual and photographic observations lead us to believe that the electrical activity is caused by the ejection from the volcano into the atmosphere of material carrying a large positive charge."

Translation? Volcanic lightning, the researchers hypothesize, is the result of charge-separation. As positively charged ejecta makes its way skyward, regions of opposite but separated electrical charges take shape. A lightning bolt is nature's way of balancing the charge distribution. The same thing is thought to happen in regular-old thunderstorms. But this much is obvious, right? So what makes volcanic lightning different?

Close to 50 years have transpired since Surtsey exploded in November 1963. Since then, only a few studies have managed to make meaningful observations of volcanic eruptions. One of the most significant was published in 2007, after researchers used radio waves to detect a previously unknown type of lightning zapping from the crater of Alaska's Mount Augustine volcano in 2006.

"During the eruption, there were lots of small lightning (bolts) or big sparks that probably came from the mouth of the crater and entered the (ash) column coming out of the volcano," said study co-author Ronald J. Thomas in a 2007 interview with National Geographic. "We saw a lot of electrical activity during the eruption and even some small flashes going from the top of the volcano up into the cloud. That hasn't been noticed before."

The observations suggest that the eruption produced a large amount of electric charge, corroborating the 1963 hypothesis – but the newly identified lightning posed an interesting puzzle: where, exactly, do these charges come from? "We're not sure if it comes out of the volcano or if it is created just afterwards," Thomas explains. "One of the things we have to find out is what's generating this charge."

Since 2007, a small handful of studies have led to the conclusion that there exist at least two types of volcanic lightning – one that occurs at the mouth of an erupting volcano, and a second that dances around in the heights of a towering plume (an example of the latter occurred in 2011 above Chile's Puyehue-Cordón Caulle volcanic complex, as pictured here. (Photograph by Carlos Gutierrez/Reuters.) Findings published in a 2012 article in the geophysics journal Eos reveal that the largest volcanic storms can rival the intensity of massive supercell thunderstorms common to the American midwest. Still, the source of the charge responsible for this humbling phenomenon remains hotly debated.

One hypothesis, floated by Thomas' team in 2007, suggests that magma, rock and volcanic ash, jettisoned during an eruption, are themselves electrically charged by some previous, unknown process, generating flashes of electricity near the volcano's opening. Another holds that highly energized air and gas, upon colliding with cooler particles in the atmosphere, generate branched lightning high above the volcano's peak. Other hypotheses, still, implicate rising water and ice-coated ash particles.

Read more at Discovery News

Mar 28, 2013

What Attracts People to Violent Movies?

Why are audiences attracted to bloodshed, gore and violence? A recent study from researchers at the University of Augsburg, Germany and the University of Wisconsin-Madison found that people are more likely to watch movies with gory scenes of violence if they felt there was meaning in confronting violent aspects of real life.

Anne Bartsch, University of Augsburg, Germany and Louise Mares, University of Wisconsin-Madison, will present their findings at the 63rd Annual Conference of the International Communication Association. Their study examined whether these serious, contemplative, and truth-seeking motivations for exposure to violent portrayals are more than just an intellectual pleasure. They invited a large binational sample from Germany and the US (total of 482 participants), ranging in age from 18-82, and with varying levels of education. Participants viewed film trailers featuring different levels of gore and meaningfulness, and rated their likelihood of watching the full movie. They also indicated their perceptions of the film (how gory, meaningful, thought-provoking, suspenseful, etc.).

Earlier studies have suggested that audiences are not necessarily attracted to violence per se, but seem to be drawn to violent content because they anticipate other benefits, such as thrill and suspense.

These findings suggest that such hedonistic pleasures are only part of the story about why we willingly expose ourselves to scenes of bloodshed and aggression. Some types of violent portrayals seem to attract audiences because they promise to satisfy truth-seeking motivations by offering meaningful insights into some aspect of the human condition.

Read more at Science Daily

Top 10 Animal Mysteries and Myths Explained

Animal behavior can often help explain the origin of popular myths and mysteries. Fairy circles, for example, have long puzzled onlookers. These are striking circular patches of perennial grasses with a barren center, which grow in the desert on the southwest coast of Africa. Biologist Norbert Juergens of the University of Hamburg and his colleagues, in a new Science paper, explain how termite feeding and natural rainwater storage produce the grass circles.

According to the researchers, termites feed on the grass roots, preventing growth. Rainwater, however, later stores in the sandy soil depths around the rim of the feeding, which allows some grass to survive.

Bigfoot Roars

Earlier this year, headlines suggested that Bigfoot was living in Oregon, after claims of strange roaring and screeching sounds coming from forests. These claims have been made for years at various locations around the world. Most experts attribute the sounds to coyotes, which vocalize in complex ways, or Barred Owls. The Cornell Lab of Ornithology shares that “the Barred Owl’s hooting call, 'Who cooks for you? Who cooks for you-all?' is a classic sound of old forests and treed swamps.”

Crop Circles

What do drugged-out wallabies have to do with crop circles, those distinctive circular patterns often seen in and around Australia? According to Lara Giddings, attorney general for the island state of Tasmania, the kangaroo-like marsupials feed in the region’s many poppy fields. "Then they crash,” she told the BBC. "We see crop circles in the poppy industry from wallabies that are high.”

The wallabies literally go around in circles, eating in that pattern or trampling the crops.

Sea Monsters

"Loch Ness monster” sightings were common in Scotland, and people have reported seeing other sea monsters in waters such as Cadboro Bay, Alaska. Animal experts believe these creatures are likely a frill shark, eel or some kind of fish. Jim Covel, senior manager of guest experience at California’s Monterey Bay Aquarium, told Discovery News that he and others can't be more specific, though, because they "do still find new species in the oceans, perhaps allowing some to entertain ideas like this, filling in the gaps with their imaginations.”

Highly endangered frill sharks do have a monster-like look, with their big toothy mouths and undulating, eel-resembling bodies.

Read more at Discovery News

Stone Age Phallus Found in Israel

Some remarkable traces of Stone Age life were unearthed recently in northern Israel, including a pit of burned bean seeds and a carving of a penis that's more than 6,000 years old, the Israeli Antiquities Authority (IAA) reported.

Archaeologists are excavating at Ahihud Junction ahead of the construction of a new Israeli railroad line to the city of Karmiel. They found evidence of ancient settlements from two eras: the Pre-Pottery Neolithic period and the Early Chalcolithic period (seventh millennium B.C. to fifth millennium B.C.).

"For the first time in the country, entire buildings and extensive habitation levels were exposed from these early periods, in which the rich material culture of the local residents was discovered," IAA excavation directors, Yitzhak Paz and Ya'akov Vardi, said in a statement this month.

"We found a large number of flint and obsidian arrowheads, polished miniature stone axes, blades and other flint and stone tools," the archaeologists added. "The large amount of tools made of obsidian, a material that is not indigenous to Israel, is indicative of the trade relations that already existed with Turkey, Georgia and other regions during this period."

The team said they also found thousands of charred broad bean seeds inside of a pit — providing an early example of legume cultivation in the Middle East — and the remains of early Chalcolithic rectangular buildings, replete with pottery, as well as flint and stone tools. Other artifacts were slightly more enigmatic, such as the phallic figurine and a palette bearing a schematic etching of female genitals. The IAA called these objects "cultic sexual symbols" that might have represented the fertility of the earth.

Israel's rich ancient history means that artifacts are often uncovered when the ground is broken for construction projects. Animal and human figurines, some more than 9,000 years old, have been found at Tel Motza, an archaeological site being excavated ahead of the expansion of Highway 1, the main road connecting Jerusalem and Tel Aviv.

Read more at Discovery News

Rare View Reveals How Earth's Crust Forms

One of the Earth's best-ever baby pictures reveals how crust forms at the biggest volcanic feature on the planet.

The detailed look at molten magma beneath a mid-ocean ridge, one of the giant undersea cracks that ring the globe like seams on a baseball, sheds light on the driving forces behind plate tectonics. The results of the study are published yesterday (March 27) in the journal Nature.

Most of the Earth (70 percent) is covered by oceanic crust, mainly basalt, formed from lava that burbles out ofmid-ocean ridges. The ridges run across some 40,000 miles (65,000 kilometers) of the seafloor. They mark where crust pulls apart, leaving space for hotter mantle rock underneath to rise up and melt.

But the particulars of this process have been fuzzy. Geoscientists lacked clear images of structures beneath the mid-ocean ridges, which would reveal how magma moves to the surface.

"The upper mantle melting region is a deep and difficult target," said Kerry Key, lead study author and a seismologist at the Scripps Institution of Oceanography in San Diego.

Key and his co-authors peered into this mysterious zone beneath the northern East Pacific Rise, a fast-spreading mid-ocean ridge near Costa Rica.

Plates pull apart, make new crust

Their new image is akin to a sonogram of the Earth, but instead of sound waves, the researchers used a technique called electromagnetic imaging, which looks for subtle variations in Earth's naturally occurring electric and magnetic fields. The variations reveal different layers and liquid beneath the surface.

Key discovered a symmetrical, narrow melt zone beneath the East Pacific Rise. This implies the mantle is simply filling space created by spreading plates, he said. If the rising mantle were pushing the plates apart, there would likely be evidence of localized convection, such as broader, asymmetrical melting.

The study supports one of the dominant theories (the passive flow model) of how mid-ocean ridges work, the researchers said. Earth's crust is like a giant conveyor belt, with plates spreading apart at mid-ocean ridges and diving into the mantle for recycling at subduction zones, Key explained. The plates ride on giant convection cells in the mantle, but mid-ocean ridges aren't linked to these massive swirls. Instead, the ridges' localized melting comes from the space created by slip-sliding tectonic plates, geologists think. However, there's ongoing debate as to whether the driving force is pull at subduction zones — the passive flow model — or push from magma coming up at ridges.

"Our data looks just like the passive flow model," Key told OurAmazingPlanet. "It agrees with what everybody thinks should be going on, but we haven't had a good image before. It looks like something somebody would have drawn in a textbook based on what we thought was going on."

How the mantle melts

The results also confirm models of mantle melting based on rocks scraped off the seafloor at mid-ocean ridges. Sometimes, pieces of the mantle are carried up to the surface with erupting lava, giving geologists a glimpse into this inaccessible part of the Earth.

The first gooey mantle rocks to melt have a high concentration of impurities, such as carbon dioxide and then water, Key said. Finally, between a depth of 37 miles (60 km) and the surface, the melt really gets going, with about 10 percent of the mantle transformed to liquid rock. Just below the surface, a vertical channel to the east of the ridge connects the magma reservoir to the fissures and volcanoes at the surface.

Read more at Discovery News

Mar 27, 2013

Huge Croc Extinction Led to Dinosaur Domination

Approximately 201 million years ago, the Triassic-Jurassic mass extinction killed off a slew of huge predators, including hefty beasts that looked like crocodiles and enormous armadillos, according to new research that also suggests dinosaurs benefitted from the losses.

Some of the prehistoric predators -- animals known collectively as the early pseudosuchians -- likely preyed on certain dinosaurs, which later evolved some of impressive characteristics of the ancient pseudosuchians. Those included features like sturdy body armor and strong tails for whacking enemies.

“It is likely, therefore, that dinosaurs prospered to some extent as a result of the extinction of most pseudosuchians and many other groups at the end of the Triassic,” co-author Richard Butler, a paleontologist at Ludwig-Maximilians-Universität, told Discovery News.

He added that some evidence suggests dinosaurs “had better locomotor and breathing systems than pseudosuchians,” so they thrived in the Jurassic after the mass extinction. As for what caused that die-off, researchers suspect an enormous burst of volcanic activity, as part of the Atlantic Ocean’s formation, led to dramatic increases in atmospheric carbon dioxide and rapid global warming.

For the latest study, published in Biology Letters, Butler and colleague Olja Toljagić assessed changes in pseudosuchians that occurred during the critical Late Triassic and Early Jurassic periods.

The study shows that during the extinction event 201 million years ago, these animals declined rapidly, with only one lineage surviving into the Jurassic. Some of the animals evolved into ancestors of today’s alligators and crocodiles. Another lineage, referred to as the “bird-line archosaurs,” consisted of the non-avian dinosaurs and their species that later evolved into modern birds.

Luck, in part, helps to explain why some animals died, while others survived.

“Selectivity of mass extinction events is sometimes linked with body size, ecological constraints and competition, while other times it could be related to just pure luck of the survivors,” Toljagić explained.

Stephen Brusatte, a paleontologist at the University of Edinburgh, previously studied how crocodile-line archosaurs changed during the Triassic and across the Triassic-Jurassic boundary.

Brusatte told Discovery News that the recent study by Butler and Toljagić is important “because we really need to understand what happens at mass extinction events in order to better understand how our own world may change in the face of warming temperatures.”

“Many early relatives of crocodiles flourished during the Triassic, but many of them were killed off at or near the Triassic," he said. "After they were killed, whole different groups of crocodile-line archosaurs had a chance to rise in their place, and it was this dramatic moment that was the root of the diversification of the lineages leading to living crocodiles.”

More than anything, he said, this study shows what can happen during and after mass extinction events.

Read more at Discovery News

Biggest Dino Killer: Volcano vs. Asteroid

Some 20 years after its conviction in slaying of the dinosaurs, the Chicxulub impact crater is facing a retrial by a growing number of geologists who think the mass extinction event 65 million years ago was caused by something much larger. Not a larger meteorite, but a far bigger disturbance that was happening on the other side of the planet before, during, and after the Chicxulub impact: the massive Deccan Traps volcanic eruption.

The latest debate over the ultimate reason for the mass extinction is occurring this week at the Natural History Museum in London. Researchers from around the world are meeting there for the International Conference of Volcanism, Impacts, and Mass Extinctions -- which includes a lot of new science on the extinction event that wiped out the dinosaurs. This is despite the fact that advocates for the Chicxulub theory published a paper three years ago, with a whopping 41 authors, reviewing the evidence and concluding once and for all that Chicxulub was the dino killer.

“That paper helped the volcanism side because it dismissed volcanism,” said Princeton University paleontologist Gerta Keller, who has long been skeptical of the timing of the Chicxulub impact and has sought answers to the Cretaceous-Tertiary (a.k.a., K-T, or Cretaceous-Paleogene) extinction in India's Deccan Traps, which are arguably the largest volcanic deposit on the planet.

While the timing has long been debatable, more recently, however, radiometric dating of the impact debris suggests the K-T event and the Chicxulub collision happened no more than 33,000 years apart.

Still, Keller's work, and that of others, has unearthed evidence that the Deccan Traps' series of eruptions were not only timed right, but they released an order of magnitude more climate altering greenhouses gases into the atmosphere than the single Chicxulub impact could have. What's more, they have been directly tied to extinctions in the oceans in that part of the world.

The research has revealed that the Deccan Traps had three main periods of eruption spanning some 2.5 million years. Each phase of eruption lasted on the order of 100,000 years or less and had within them powerful pulses that released roughly 10,000 cubic kilometers (2,400 cubic miles) of lava in less than a century and maybe even in just a decade, explained Vincent Courtillot of the University of Paris, who is among those presenting at the meeting.

Read more at Discovery News

First Love Child of Human, Neanderthal Found

The skeletal remains of an individual living in northern Italy 40,000-30,000 years ago are believed to be that of a human/Neanderthal hybrid, according to a paper in PLoS ONE.

If further analysis proves the theory correct, the remains belonged to the first known such hybrid, providing direct evidence that humans and Neanderthals interbred. Prior genetic research determined the DNA of people with European and Asian ancestry is 1 to 4 percent Neanderthal.

The present study focuses on the individual’s jaw, which was unearthed at a rock-shelter called Riparo di Mezzena in the Monti Lessini region of Italy. Both Neanderthals and modern humans inhabited Europe at the time.

“From the morphology of the lower jaw, the face of the Mezzena individual would have looked somehow intermediate between classic Neanderthals, who had a rather receding lower jaw (no chin), and the modern humans, who present a projecting lower jaw with a strongly developed chin,” co-author Silvana Condemi, an anthropologist, told Discovery News.

Condemi is the CNRS research director at the University of Ai-Marseille. She and her colleagues studied the remains via DNA analysis and 3D imaging. They then compared those results with the same features from Homo sapiens.

The genetic analysis shows that the individual’s mitochondrial DNA is Neanderthal. Since this DNA is transmitted from a mother to her child, the researchers conclude that it was a “female Neanderthal who mated with male Homo sapiens.”

By the time modern humans arrived in the area, the Neanderthals had already established their own culture, Mousterian, which lasted some 200,000 years. Numerous flint tools, such as axes and spear points, have been associated with the Mousterian. The artifacts are typically found in rock shelters, such as the Riparo di Mezzena, and caves throughout Europe.

The researchers found that, although the hybridization between the two hominid species likely took place, the Neanderthals continued to uphold their own cultural traditions.

That's an intriguing clue, because it suggests that the two populations did not simply meet, mate and merge into a single group.

As Condemi and her colleagues wrote, the mandible supports the theory of "a slow process of replacement of Neanderthals by the invading modern human populations, as well as additional evidence of the upholding of the Neanderthals' cultural identity.”

Prior fossil finds indicate that modern humans were living in a southern Italy cave as early as 45,000 years ago. Modern humans and Neanderthals therefore lived in roughly the same regions for thousands of years, but the new human arrivals, from the Neanderthal perspective, might not have been welcome, and for good reason. The research team hints that the modern humans may have raped female Neanderthals, bringing to mind modern cases of "ethnic cleansing."

Read more at Discovery News

Fattest Stars are Force-Fed at an Early Age

Star formation is a complex and beautiful process, but the reasons as to why the biggest stars get so massive has been a mystery to science.

Now, in research led by University of Toronto astronomers, it seems the fattest stars likely form when they are surrounded by a cluster of older stars, which force-feed them gas, causing them to beef-up to gargantuan proportions during their formative years.

Using data from the European Herschel infrared space observatory, gas swirling around the Westerhout 3 (W3) giant molecular cloud (GMC), some 6,500 light-years away, appears to show the ultimate buddy system at work. Corralled inside a cluster of older stars, young stars are in the perfect location to receive an optimized quantity of gas confined inside the stellar nursery from their older siblings.

The result? They’re getting bloated on the rich supply of gaseous matter, a supply they wouldn’t be able to capture if they were on their own.

During star formation, the intense radiation generated by young stars creates an outward pressure, pushing surrounding gas away. There is a theoretical maximum of the mass of any given star; they form from the gravitational collapse of a surrounding gas cloud, ignite and then blast the remaining gas away with intense ultraviolet radiation, preventing them from growing any further. Scientists estimate that the most massive stars should grow to a maximum of eight times the mass of the sun. In W3, there are much bigger specimens — O-type stars are known to exist inside, young main sequence stars that can outshine the sun a million times up to 90 times more massive.

“The radiation during the birth of high-mass stars is so intense that it tends to destroy and push away the material from which they need to feed for further growth,” said Alana Rivera-Ingraham, a postdoctoral researcher at the Institut de Recherche en Astrophysique et Planétologie in Toulouse, France. She led the W3 study when she was graduate student at the University of Toronto.

But, as Rivera-Ingraham’s team discovered, deep inside W3 there’s another factor at play — older stars counteract this outward pressure, forcing gas into the stellar nursery.

In their paper, the researchers say: “our results indicate that an active/dynamic process aiding in the accumulation, compression, and confinement of material is a critical feature of the high-mass star/cluster formation, distinguishing it from classical low-mass star formation.” This research will be published in the April edition of The Astrophysical Journal and an arXiv preprint is available online. The W3 cluster is basically acting like a stellar pressure cooker.

Observing stellar nurseries inside thick molecular clouds can be a tricky process, but Herschel is sensitive to the infrared radiation generated by cool dust and gas. This radiation can escape through the obscuring clouds that is opaque to visible light, highlighting where the gas is accumulating and forming stars.

Read more at Discovery News

Mar 26, 2013

Unique Mechanisms of Antibiotic Resistance Identified

As public health authorities across the globe grapple with the growing problem of antibiotic resistance, Tufts University School of Medicine microbiologists and colleagues have identified the unique resistance mechanisms of a clinical isolate of E. coli resistant to carbapenems. Carbapenems are a class of antibiotics used as a last resort for the treatment of disease-causing bacteria, including E. coli and Klebsiella pneumonia, which can cause serious illness and even death. Infections involving resistant strains fail to respond to antibiotic treatments, which can lead to prolonged illness and greater risk of death, as well as significant public health challenges due to increased transmission of infection.

The study, published in the April issue of Antimicrobial Agents and Chemotherapy, demonstrates the lengths to which bacteria will go to become resistant to antibiotics.

Resistance to carbapenems usually emerges through the acquisition of an enzyme, carbapenemase, which destroys the antibiotic intended to treat infection. Resistance may also block entry of the drug into the E-coli bacteria. The current research, led by corresponding author Stuart Levy, M.D., Professor of Molecular Biology & Microbiology and of Medicine and Director of the Center for Adaptation Genetics & Drug Resistance at Tufts University School of Medicine, sought to determine what made this particular clinical isolate of E. coli resistant to carbapenem in the absence of carbapenemase.

"The Centers for Disease Control and Prevention has documented a significant increase in Carbapenem-resistant Enterobacteriaceae (CRE) -- so-called 'super bugs' that have been found to fight off even the most potent treatments," Levy said. "We knew that bacteria could resist carbapenems, but we had never before seen E. coli adapt so extensively to defeat an antibiotic. Our research shows just how far bacteria will go with mutations in order to survive."

Levy and his colleagues determined that the E. coli genetically mutated four separate times in order to resist carbapenems. Specifically, the isolate removed two membrane proteins in order to prevent antibiotics from getting into the cell. The bacteria also carried a mutation of the regulatory protein marR, which controls how bacteria react in the presence of antibiotics. The isolate further achieved resistance by increasing expression of a multidrug efflux pump. Moreover, the researchers discovered that the E. coli was expressing a new protein, called yedS, which helped the drug enter the cell, but whose expression was curtailed by the marR mutation. yedS is a normally inactive protein acquired by some E. coli that affects how the drug enters the bacterial cell. It is generally expressed in bacteria through a mutation.

According to the Centers for Disease Control and Prevention, CRE germs have increased from 1% to 4% in the United States over the last decade. Forty-two states report having identified at least one patient with one type of CRE. Approximately 18% of long-term acute care hospitals in the United States and 4% of short-stay hospitals reported at least one CRE infection in the first half of 2012.

The clinical isolate of E. coli studied by Levy and his colleagues came from the sputum of a patient at Peking Union Medical College Hospital in Beijing, China, where three of the study authors are on the faculty. Drug resistance is a particularly serious public health concern in China, antibiotics are overprescribed and used widely in the livestock and farming industries.

"The first quinolone-resistant strains of bacteria came out of China, where we see that the drugs of last resort begin being used, because the other drugs don't work after so much overuse," Levy said.

Read more at Science Daily

Trees Used to Create Recyclable, Efficient Solar Cell

Solar cells are just like leaves, capturing the sunlight and turning it into energy. It's fitting that they can now be made partially from trees.

Georgia Institute of Technology and Purdue University researchers have developed efficient solar cells using natural substrates derived from plants such as trees. Just as importantly, by fabricating them on cellulose nanocrystal (CNC) substrates, the solar cells can be quickly recycled in water at the end of their lifecycle.

The technology is published in the journal Scientific Reports, the latest open-access journal from the Nature Publishing Group.

The researchers report that the organic solar cells reach a power conversion efficiency of 2.7 percent, an unprecedented figure for cells on substrates derived from renewable raw materials. The CNC substrates on which the solar cells are fabricated are optically transparent, enabling light to pass through them before being absorbed by a very thin layer of an organic semiconductor. During the recycling process, the solar cells are simply immersed in water at room temperature. Within only minutes, the CNC substrate dissolves and the solar cell can be separated easily into its major components.

Georgia Tech College of Engineering Professor Bernard Kippelen led the study and says his team's project opens the door for a truly recyclable, sustainable and renewable solar cell technology.

"The development and performance of organic substrates in solar technology continues to improve, providing engineers with a good indication of future applications," said Kippelen, who is also the director of Georgia Tech's Center for Organic Photonics and Electronics (COPE). "But organic solar cells must be recyclable. Otherwise we are simply solving one problem, less dependence on fossil fuels, while creating another, a technology that produces energy from renewable sources but is not disposable at the end of its lifecycle."

To date, organic solar cells have been typically fabricated on glass or plastic. Neither is easily recyclable, and petroleum-based substrates are not very eco-friendly. For instance, if cells fabricated on glass were to break during manufacturing or installation, the useless materials would be difficult to dispose of. Paper substrates are better for the environment, but have shown limited performance because of high surface roughness or porosity. However, cellulose nanomaterials made from wood are green, renewable and sustainable. The substrates have a low surface roughness of only about two nanometers.

"Our next steps will be to work toward improving the power conversion efficiency over 10 percent, levels similar to solar cells fabricated on glass or petroleum-based substrates," said Kippelen. The group plans to achieve this by optimizing the optical properties of the solar cell's electrode.

Purdue School of Materials Engineering associate professor Jeffrey Youngblood collaborated with Kippelen on the research.

A provisional patent on the technology has been filed with the U.S. Patent Office.

Read more at Science Daily

Astronomers Discover New Kind of Supernova

Supernovae were always thought to occur in two main varieties. But a team of astronomers including Carnegie's Wendy Freedman, Mark Phillips and Eric Persson is reporting the discovery of a new type of supernova called Type Iax.

This research has been accepted for publication in The Astrophysical Journal.

Previously, supernovae were divided into either core-collapse or Type Ia categories. Core-collapse supernovae are the explosion of a star about 10 to 100 times as massive as our sun. Type Ia supernovae are the complete disruption of a tiny white dwarf.

This new type, Iax, is fainter and less energetic than Type Ia. Although both types come from exploding white dwarfs, Type Iax supernovas may not completely destroy the white dwarf. "A Type Iax supernova is essentially a mini supernova," says lead author Ryan Foley, Clay Fellow at the Harvard-Smithsonian Center for Astrophysics (CfA). "It's the runt of the supernova litter."

The research team--which also included Max Stritzinger, formerly of Carnegie--identified 25 examples of the new type of supernova. None of them appeared in elliptical galaxies, which are filled with old stars. This suggests that Type Iax supernovas come from young star systems.

Based on a variety of observational data, the team concluded that a Type Iax supernova comes from a binary star system containing a white dwarf and a companion star that has lost its outer hydrogen, leaving it helium dominated. The white dwarf collects helium from the normal star.

Researchers aren't sure what triggers a Type Iax. It's possible that the outer helium layer ignites first, sending a shock wave into the white dwarf. Alternatively, the white dwarf might ignite first due to the influence of the overlying helium shell.

Either way, it appears that in many cases the white dwarf survives the explosion, unlike in a Type Ia supernova where the white dwarf is completely destroyed.

The team calculates that Type Iax supernovae are about a third as common as Type Ia supernovae. The reason so few have been detected is that the faintest are only one-hundredth as bright as a Type Ia supernova.

"The closer we look, the more ways we find for stars to explode," Phillips said.

Read more at Science Daily

Found: Africa's Oldest Penguins

Penguin fossils from 10 million to 12 million years ago have been unearthed in South Africa, the oldest fossil evidence of these cuddly, tuxedoed birds in Africa.

The new discovery, detailed in the March 26 issue of the Zoological Journal of the Linnean Society, could shed light on why the number of penguin species plummeted on Africa's coastline from four species 5 million years ago to just one today — Spheniscus demersus, or the jackass penguin, known for their donkeylike calls.

Daniel Thomas, a researcher at the National Museum of Natural History, and colleague Daniel Ksepka of the National Evolutionary Synthesis Center were studying rock sediments near a steel plant in Cape Town, South Africa, when they uncovered an assortment of fossils, including 17 pieces that turned out to be backbones, breastbones, legs and wings from ancient penguins.

The bones suggested these ancient birds ranged from 1-to-3 feet tall (0.3 to 0.9 meters). For comparison, Africa's living jackass penguin, also called the black-footed penguin, stands at about 2-feet tall (0.6 meters) and weighs between 5.5 and 8.8 pounds (2.5 and 4 kilograms).

The discovery pushes back the penguin fossil record in Africa by at least 5 million years.

Because the next oldest fossils from Africa date to 5 million years ago, it's tricky to determine exactly why most penguin species disappeared from Africa.

"It's like seeing two frames of a movie," Ksepka said in a statement. "We have a frame at five million years ago, and a frame at 10-12 million years ago, but there's missing footage in between."

One possibility is that changing sea levels eliminated most of the penguins' nesting sites.

About 5 million years ago, sea levels were 296 feet (90 m) higher than today, and the low-lying South Africa became a patchwork of islands. Those islands provided beaches for several penguin species to create nests and rear their young while sheltering them from predators.

Read more at Discovery News

Mar 25, 2013

A Tiny Grain Helps Reveal the History of a Rock

Researchers can use the mineral rutile to learn about rock types and their history. Two articles published in the journal Geology now present a new application of a method for more easily tracing the mineral rutile. The co-authors of the articles are researchers at the University of Gothenburg.

Rutile is used in ceramics and paints, but is particularly useful for finding out about the history of a rock.

Where mineral deposits are found, rutile is often also present. The new methods therefore bring opportunities for strategies to find other mineral deposits, such as gold.

Until now, rutile has been a relatively unknown mineral, despite not being rare. For example, rutile can be found on most sandy beaches around the world, including in Sweden.

"It's incredible to see how little attention was paid to rutile until around five years ago," says geologist and researcher Thomas Zack, from the University of Gothenburg's Department of Earth Sciences, who has devoted much of his scientific career to studying the mineral.

Now, geologists can identify rock types containing rutile and follow the changes in temperature and pressure that they have been exposed to throughout its history, even if rutile is barely visible to the naked eye. Previously, researchers had to investigate considerably more rutile-bearing samples in order to carry out analyses.

"But now we can identify the rock from which the rutile originates, even if we only have a tiny grain of rutile," adds Thomas Zack.

The new method is called "Laser Ablation ICP-MS," and produces results much faster than previous methods.

Read more at Science Daily

Developing Our Sense of Smell

When our noses pick up a scent, whether the aroma of a sweet rose or the sweat of a stranger at the gym, two types of sensory neurons are at work in sensing that odor or pheromone. These sensory neurons are particularly interesting because they are the only neurons in our bodies that regenerate throughout adult life -- as some of our olfactory neurons die, they are soon replaced by newborns. Just where those neurons come from in the first place has long perplexed developmental biologists.

Previous hypotheses about the origin of these olfactory nerve cells have given credit to embryonic cells that develop into skin or the central nervous system, where ear and eye sensory neurons, respectively, are thought to originate. But biologists at the California Institute of Technology (Caltech) have now found that neural-crest stem cells -- multipotent, migratory cells unique to vertebrates that give rise to many structures in the body such as facial bones and smooth muscle -- also play a key role in building olfactory sensory neurons in the nose.

"Olfactory neurons have long been thought to be solely derived from a thickened portion of the ectoderm; our results directly refute that concept," says Marianne Bronner, the Albert Billings Ruddock Professor of Biology at Caltech and corresponding author of a paper published in the journal eLIFE on March 19 that outlines the findings.

The two main types of sensory neurons in the olfactory system are ciliated neurons, which detect volatile scents, and microvillous neurons, which usually sense pheromones. Both of these types are found in the tissue lining the inside of the nasal cavity and transmit sensory information to the central nervous system for processing.

In the new study, the researchers showed that during embryonic development, neural-crest stem cells differentiate into the microvillous neurons, which had long been assumed to arise from the same source as the odor-sensing ciliated neurons. Moreover, they demonstrated that different factors are necessary for the development of these two types of neurons. By eliminating a gene called Sox10, they were able to show that formation of microvillous neurons is blocked whereas ciliated neurons are unaffected.

They made this discovery by studying the development of the olfactory system in zebrafish -- a useful model organism for developmental biology studies due to the optical clarity of the free-swimming embryo. Understanding the origins of olfactory neurons and the process of neuron formation is important for developing therapeutic applications for conditions like anosmia, or the inability to smell, says Bronner.

"A key question in developmental biology -- the extent of neural-crest stem cell contribution to the olfactory system -- has been addressed in our paper by multiple lines of experimentation," says Ankur Saxena, a postdoctoral scholar in Bronner's laboratory and lead author of the study. "Olfactory neurons are unique in their renewal capacity across species, so by learning how they form, we may gain insights into how neurons in general can be induced to differentiate or regenerate. That knowledge, in turn, may provide new avenues for pursuing treatment of neurological disorders or injury in humans."

Read more at Science Daily

Earth's Crust Does the 'Caterpillar Walk'

The geological mystery of how colliding tectonic plates can force some rocks very deep into the Earth, then pop them quickly back to the surface, may have been solved with what’s being called a “caterpillar walk.”

The classic way of thinking about colliding plates is that one plate is shoved under another and they just keep ramming towards one another. The plate that goes under eventually peels off into the mantle and is gone. But that doesn’t explain how rocks that get pulled down and altered by the pressure so they become loaded with ultra-high pressure minerals — like the metamorphic eclogite rock shown above in my hand and at right — get boosted back to the surface so quickly. We know it happens because these pressure-altered rocks are found at the surface.

A team of European geologist have looked at the situation in the Aegean and have come up with a model that might explain it. They propose that when plates collided in the Aegean, the sinking plate, as it peeled away and sank into the mantle, sucked down some rocks with it that were then quickly (geologically speaking, which means over millions of years) caught up in the upward flow of material that filled the space of the sinking plate. An analogy, if I’m getting this right, might be the way water would rush in if you quickly separate your hands underwater. The authors of the paper, in the latest issue of Geology, made a movie of the process that you can see here.

Anyway, this upwards flow of rock created an area of the Earth’s crust that was no longer smashing together, but stretching out. That means there are lots of vertical faults allowing deep rocks to rise to the surface (in the same was that a row of tilted books on a book shelf eventually reveal lower and lower portions of books if you allow them to spread out over the length of the shelf). Add to that the normal erosion of rocks by weather, and you should be able to get eclogites up in record time.

The caterpillar part comes in when you follow the rocks in the collision zone. At first they are bunched up and pulled down into the collision zone, then they are sucked up again and spread out in the crust. Think caterpillar on the ceiling. First spread out flat, then bunched up (collision and pressurization of the rocks) then spread out again (and the rocks that were deep are now shallow).

And just in case anyone was wondering, the fact that this process brings up metamorphic rocks does not mean they are in way connected to the metamorphosis of a caterpillar into a butterfly. It’s just a fun semantic coincidence.

From Discovery News

Where's the Edge of the Solar System? It's Complicated...

If you thought finding a definition for Pluto was contentious, try defining the edge of the solar system.

A press release from the American Geophysical Union (AGU) last week announced that on August 25, 2012, NASA’s Voyager 1, officially entered interstellar space. This milestone comes after speeding across the solar system for 35 years following its landmark flybys of the Jovian and Saturnian system. The AGU release title read: “Voyager 1 Has Left The Solar System, Sudden Changes In Cosmic Rays Indicate.”

The threshold is described by the authors of the paper, published in Geophysical Journal Letters, as Voyager’s measurement of a substantial increase in the level of galactic cosmic rays slamming into the 1,700 pound spacecraft. This is seen as evidence that Voyager may have crossed a cliff called the heliopause, the edge of tenuous immense bubble of plasma and charged particles blown into space by the solar wind.

The paper abstract reports: “ has crossed a well-defined boundary for energetic particles at this time possibly related to the heliopause.”

But hold on.

Within hours of the AGU release NASA’s Jet Propulsion Laboratory posted a terse press statement that the Voyager team insists the spacecraft has not yet reached interstellar space. The team has a different criterion: a change in the direction of the magnetic field between the of the sun and the interstellar medium. They said the this transition has not yet been measured as Voyager hurtles toward the stars at 38,000 miles per hour.

The same day the AGU news office back peddled and changed the press release title to “Voyager 1 Has Entered A New Region Of Space, Sudden Changes In Cosmic Rays Indicate.” (yawn)

Stories of Voyager crossing something new on its departure from the solar system have been perennial.

A year ago it was reported that Voyager passed the so-called termination shock. This is where the solar wind of charges particles abruptly slows, indicating Voyager’s entry into an outer region called the heliosheath.

Only last August the Voyager team reported that its robot explorer had entered an unknown “magnetic highway” where magnetic fields inside and outside the heliosphere connect up. (Don’t worry; there won’t be a quiz after all this.)

If you are befuddled by all this, so am I, especially because I can’t see any of it like I can see auroras on Jupiter or the delicate gravitational ripples in the rings of Saturn.

What’s humbling is that Voyager 1 has only traveled 0.02 light-year (11 billion miles) since its launch in 1977. Star Trek’s Captain Kirk could cover that distance in less time than it would take him to finish his morning latte.

Does it sound a little presumptive to say that Voyager is on the cusp of entering an interstellar mission phase?

More fundamentally, who gets to unequivocally define the official edge of the solar system?

If it’s the heliopause, then it is compounded by the fact that the heliosphere is teardrop- shaped due to the sun plowing through the interstellar medium like a ship on the ocean. The “edge” is at a significantly different distance from the sun depending on a spacecraft’s outbound trajectory.

I’d say that the entire debate is terribly esoteric for the public even though it involves specific milepost signs that are important to astrophysicists for mapping the sun’s relationship to the cold and vacuous interstellar medium.

This “exo-solar system” is an unexplored phantom frontier as intriguing to scientists as exploring the Louisiana Purchase was to Lewis and Clark.

Why not simply use a dynamical argument for defining the solar system’s perimeter that is not as subject to data interpretation? This could be when Voyager 1 reaches the hypothetical Oort cloud of comets, 18,000 years from now. That’s where the sun’s gravitational field keeps a weak hold on primeval objects — at a distance of 6 trillion miles, or one light-year.

Read more at Discovery News

Mar 24, 2013

Venus Vortices Go for Chaotic Multi-Storey Strolls Around the Poles

A detailed study of Venus' South Polar Vortex shows a much more chaotic and unpredictable cyclone than previously thought. The analysis reveals that the center of rotation of the vortex wanders around the pole differently at different altitude levels in the clouds of Venus. In its stroll around the Pole, in layers separated by 20 km, the vortex experiences unpredictable changes in its morphology.

The results of this study are published online in Nature Geoscience today.

The study, entitled 'A chaotic long-lived vortex at the southern pole of Venus', used infrared images from VIRTIS instrument onboard the European Space Agency's Venus Express spacecraft. VIRTIS provides spectral images at different levels of the atmosphere and allows the observation of the lower and upper clouds of Venus.

Atmospheric vortices are common in the atmospheres of different planets of the Solar System, although they have different behaviors. Venus is a planet similar to Earth in size, but very different in other aspects. It rotates slowly around its axis, with a day on Venus lasting 243 Earth-days, and it spins in the opposite direction to Earth. Its dense carbon dioxide atmosphere, with surface pressures of 90 times that of Earth, causes a runaway greenhouse effect that raises the surface temperatures up to 450ºC. Between 45 and 70km above the surface there is a dense layer of sulfuric acid clouds that completely covers the planet and moves at speeds of 360km/h in a phenomenon named superrotation, where the atmosphere rotates much faster than the surface of the planet. The origin of this effect is still unknown.

At the poles of Venus, the atmospheric circulation forms intense and permanent vortices that change shape and size on a daily basis. In the new analysis published today, researchers report that the winds in the vortex, which were tracked by studying images obtained by the Venus Express orbiter, change chaotically from day-to-day. This unpredictable nature of the Venus polar vortices make them different from polar vortices found on other planets, like Earth or Saturn, which are much more stable and predictable.

The large-scale cyclone extends vertically in Venus' atmosphere over more than 20 kilometers, through a region of highly turbulent, permanent clouds. However, the centers of rotation at two different altitude levels (42 and 62 km above the surface) are not aligned and both wander around the south pole of the planet with no established pattern at velocities of up to 55km/h. The study also finds that even when averaged cross-winds are roughly the same at both altitudes, there is still a strong vertical gradient, with winds increasing by as much as 3km/h for every kilometer of height and leading to possible atmospheric instabilities.

Read more at Science Daily

Hubble Digs Up Galactic Glow Worm

The image of a charming and bright galaxy, known as IRAS 23436+5257, was captured by the NASA/ESA Hubble Space Telescope. It is located in the northern constellation of Cassiopeia, which is named after an arrogant, vain, and yet beautiful mythical queen.

The twisted, wormlike structure of this galaxy is most likely the result of a collision and subsequent merger of two galaxies. Such interactions are quite common in the universe, and they can range from minor interactions involving a satellite galaxy being caught by a spiral arm, to major galactic crashes. Friction between the gas and dust during a collision can have a major effect on the galaxies involved, morphing the shape of the original galaxies and creating interesting new structures.

When you look up at the calm and quiet night sky it is not always easy to picture it as a dynamic and vibrant environment with entire galaxies in motion, spinning like children's toys and crashing into whatever crosses their path. The motions are, of course, extremely slow, and occur over millions or even billions of years.

The aftermath of these galactic collisions helps scientists to understand how these movements occur and what may be in store for our own Milky Way, which is on a collision course with a neighboring galaxy, Messier 31.

From Science Daily