A World with Four Suns

A planet has been discovered orbiting in a four-star system — and no, that doesn’t mean the accommodations and conditions are excellent. It literally means four stars, where a planet is orbiting a binary star system that in turn is orbited by a second distant pair of stars. This is the first system like this that has ever been found, and its discovery demonstrates the power of citizen scientists, as it was found by joint effort of amateurs participating on the Planet Hunters website under the guidance of professional astronomers.

This is might be an extremely rare planetary setup, astronomer Meg Schwamb from Yale says, as only six planets are currently known to orbit two stars, and none of these are orbited by other stellar companions. Astronomers are calling the newly found world a ‘circumbinary’ planet.

“Circumbinary planets are the extremes of planet formation,” said Schwamb, Planet Hunters scientist and lead author of a paper about the system presented Oct. 15 at the annual meeting of the Division for Planetary Sciences of the American Astronomical Society in Reno, Nevada. “The discovery of these systems is forcing us to go back to the drawing board to understand how such planets can assemble and evolve in these dynamically challenging environments.”

The planet is called PH1, for the first confirmed planet identified by the Planet Hunters citizen scientists, but it has the nickname of Tatooine, the planet in Star Wars that orbited two suns.

Planet Hunters uses data from the Kepler spacecraft, specially designed for looking for signs of planets.

Fossil Collector Seeks ID from Karoo Specimen

I stumbled across a forum where the collector had purchased a fossil and is seeking an ID.   Any of the pro-paleo types (or gifted amateurs) have a clue what it is?   The individual claims its from the Karoo supergroup.

Modern Benthic Fauna Originated in the Mesozoic

Ancient Origin of the Modern Deep-Sea Fauna

Authors:

1. Ben Thuy (a,*)
2. Andy S. Gale (b)
3. Andreas Kroh (c)
4. Michal Kucera (d)
5. Lea D. Numberger-Thuy (e)
6. Mike Reich (a,e)
7. Sabine Stöhr (f)

Affiliations:

a. Geoscience Centre, University of Göttingen, Department of Geobiology, Göttingen, Germany

b School of Earth and Environmental Sciences, University of Portsmouth, Portsmouth, United Kingdom

c. Natural History Museum Vienna, Department of Geology and Palaeontology, Vienna, Austria,

d. Marum – Centre for Marine Environmental Sciences, University of Bremen, Bremen, Germany,

e. Geoscience Centre, Museum, Collections and Geopark, University of Göttingen, Göttingen, Germany,

f. Swedish Museum of Natural History, Stockholm, Sweden

Abstract:

The origin and possible antiquity of the spectacularly diverse modern deep-sea fauna has been debated since the beginning of deep-sea research in the mid-nineteenth century. Recent hypotheses, based on biogeographic patterns and molecular clock estimates, support a latest Mesozoic or early Cenozoic date for the origin of key groups of the present deep-sea fauna (echinoids, octopods). This relatively young age is consistent with hypotheses that argue for extensive extinction during Jurassic and Cretaceous Oceanic Anoxic Events (OAEs) and the mid-Cenozoic cooling of deep-water masses, implying repeated re-colonization by immigration of taxa from shallow-water habitats. Here we report on a well-preserved echinoderm assemblage from deep-sea (1000–1500 m paleodepth) sediments of the NE-Atlantic of Early Cretaceous age (114 Ma). The assemblage is strikingly similar to that of extant bathyal echinoderm communities in composition, including families and genera found exclusively in modern deep-sea habitats. A number of taxa found in the assemblage have no fossil record at shelf depths postdating the assemblage, which precludes the possibility of deep-sea recolonization from shallow habitats following episodic extinction at least for those groups. Our discovery provides the first key fossil evidence that a significant part of the modern deep-sea fauna is considerably older than previously assumed. As a consequence, most major paleoceanographic events had far less impact on the diversity of deep-sea faunas than has been implied. It also suggests that deep-sea biota are more resilient to extinction events than shallow-water forms, and that the unusual deep-sea environment, indeed, provides evolutionary stability which is very rarely punctuated on macroevolutionary time scales.

Read it. It strongly suggests that the anoxic/hypoxic events had less effect on the extinctions than has been thought before. Or the events as seen in the Cretaceous may not have been as wide spread, I suppose, or the modern fauna were plenty of refugia during those events...

Huygens Bumped and Bounced During Landing

This video isn't mine.  I got it from the title link.  I could not find a way to embed otherwise, but...

Exoplanetary Super Earths Can Be Really Weird or 55 Cancerii e is Made of Diamond

New research led by Yale University scientists suggests that a rocky planet twice Earth's size orbiting a nearby star is a diamond planet.

"This is our first glimpse of a rocky world with a fundamentally different chemistry from Earth," said lead researcher Nikku Madhusudhan, a Yale postdoctoral researcher in physics and astronomy. "The surface of this planet is likely covered in graphite and diamond rather than water and granite."

The paper reporting the findings has been accepted for publication in the journal Astrophysical Journal Letters.

The planet — called 55 Cancri e — has a radius twice Earth's, and a mass eight times greater, making it a "super-Earth." It is one of five planets orbiting a sun-like star, 55 Cancri, that is located 40 light years from Earth yet visible to the naked eye in the constellation of Cancer.

The planet orbits at hyper speed — its year lasts just 18 hours, in contrast to Earth's 365 days. It is also blazingly hot, with a temperature of about 3,900 degrees Fahrenheit, researchers said, a far cry from a habitable world.

The planet was first observed transiting its star last year, allowing astronomers to measure its radius for the first time. This new information, combined with the most recent estimate of its mass, allowed Madhusudhan and colleagues to infer its chemical composition using models of its interior and computing all possible combinations of elements and compounds that would yield those specific characteristics.

Astronomers had previously reported that the host star has more carbon than oxygen, and Madhusudhan and colleagues confirmed that substantial amounts of carbon and silicon carbide, and a negligible amount of water ice, were available during the planet's formation.

Astronomers also thought 55 Cancri e contained a substantial amount of super-heated water, based on the assumption that its chemical makeup was similar to Earth's, Madhusudhan said. But the new research suggests the planet has no water at all, and appears to be composed primarily of carbon (as graphite and diamond), iron, silicon carbide, and, possibly, some silicates. The study estimates that at least a third of the planet's mass — the equivalent of about three Earth masses — could be diamond.

"By contrast, Earth's interior is rich in oxygen, but extremely poor in carbon — less than a part in thousand by mass," says co-author and Yale geophysicist Kanani Lee.

The identification of a carbon-rich super-Earth means that distant rocky planets can no longer be assumed to have chemical constituents, interiors, atmospheres, or biologies similar to those of Earth, Madhusudhan said. The discovery also opens new avenues for the study of geochemistry and geophysical processes in Earth-sized alien planets. A carbon-rich composition could influence the planet's thermal evolution and plate tectonics, for example, with implications for volcanism, seismic activity, and mountain formation.

It almost seems like Pulp SF setting.  Just goes to show you how wonderful and weird the universe truly is.

Cretaceous Climate was Rather Complex

Cenomanian climate zones

New thoughts about the cretaceous climate and oceans

Authors:

1. William W. Hay (a)
2. Sascha Floegel (b)

Affiliations:

a Department of Geological Sciences, University of Colorado at Boulder, 2045 Windcliff Dr. Estes Park, CO 80517, USA

b. GEOMAR | Helmholtz-Zentrum für Ozeanforschung Kiel, Gebäude Ostufer, Wischhofstr. 1–3, D-24148 Kiel, Germany

Abstract:

Several new discoveries suggest that the climate of the Cretaceous may have been more different from that of today than has been previously supposed. Detailed maps of climate sensitive fossils and sediments compiled by Nicolai Chumakov and his colleagues in Russia indicate widespread aridity in the equatorial region during the Early Cretaceous. The very warm ocean temperatures postulated for the Mid-Cretaceous by some authors would likely have resulted in unacceptable heat stress for land plants at those latitudes, however, and may be flawed.

Seasonal reversals of the atmospheric pressure systems in the Polar Regions are an oversimplification. However, seasonal pressure difference between 30° and 60° latitude become quite pronounced, being more than 25 hPa in winter and less than 10 hPa in summer. This results in inconstant winds, affecting the development of the gyre-limiting frontal systems that control modern ocean circulation. The idea of Hasegawa et al. (2011) who suggest a drastic reduction in the size of the Hadley cells during the warm Cretaceous greenhouse is supported by several numerical climate simulations. Rapid contraction of the Hadley cell such that its sinking dry air occurs at 15° N latitude rather than 30° N is proposed to occur at a threshold of 1,000 ppmv CO2 in the atmosphere. This change will probably be reached in the next century.

There is a really, really important chunk here about RUBISCO: the equatorial terrestrial environment may have been a wasteland and lifeless at times. Huber pointed this out about the PETM as well. It is entirely possible we could get to that point with global warming/climate change.  The above, btw, does not address as far as I can see, the evidence of ice in Australia during the early cretaceous. 

Complex brain and optic lobes in an early Cambrian arthropod

Complex brain and optic lobes in an early Cambrian arthropod

Authors:

1. Xiaoya Ma (a)
2. Xianguang Hou (a)
3. Gregory D. Edgecombe (c)
4. Nicholas J. Strausfeld (d)

Affiliations:

a. Yunnan Key Laboratory for Palaeobiology, Yunnan University, Kunming 650091, China

b. Department of Earth Sciences, The Natural History Museum, Cromwell Road, London SW7 5BD, UK

c. Department of Neuroscience and Center for Insect Science, University of Arizona, Tucson, Arizona 85721, USA

Abstract:

The nervous system provides a fundamental source of data for understanding the evolutionary relationships between major arthropod groups. Fossil arthropods rarely preserve neural tissue. As a result, inferring sensory and motor attributes of Cambrian taxa has been limited to interpreting external features, such as compound eyes or sensilla decorating appendages, and early-diverging arthropods have scarcely been analysed in the context of nervous system evolution. Here we report exceptional preservation of the brain and optic lobes of a stem-group arthropod from 520 million years ago (Myr ago), Fuxianhuia protensa, exhibiting the most compelling neuroanatomy known from the Cambrian. The protocerebrum of Fuxianhuia is supplied by optic lobes evidencing traces of three nested optic centres serving forward-viewing eyes. Nerves from uniramous antennae define the deutocerebrum, and a stout pair of more caudal nerves indicates a contiguous tritocerebral component. Fuxianhuia shares a tripartite pre-stomodeal brain and nested optic neuropils with extant Malacostraca and Insecta demonstrating that these characters were present in some of the earliest derived arthropods. The brain of Fuxianhuia impacts molecular analyses that advocate either a branchiopod-like ancestor of Hexapoda or remipedes and possibly cephalocarids as sister groups of Hexapoda. Resolving arguments about whether the simple brain of a branchiopod approximates an ancestral insect brain or whether it is the result of secondary simplification has until now been hindered by lack of fossil evidence. The complex brain of Fuxianhuia accords with cladistic analyses on the basis of neural characters, suggesting that Branchiopoda derive from a malacostracan-like ancestor but underwent evolutionary reduction and character reversal of brain centres that are common to hexapods and malacostracans. The early origin of sophisticated brains provides a probable driver for versatile visual behaviours, a view that accords with compound eyes from the early Cambrian that were, in size and resolution, equal to those of modern insects and malacostracans.

Genomic Evidence for Large, Long-Lived Ancestors to Placental mammals.

Genomic Evidence for Large, Long-Lived Ancestors to Placental mammals.

Authors:

1. Romiguier J. (a)
2. Ranwez V. (a,b)
3. Douzery E.J.P. (a)
4. Galtier N. (a,*)

Affiliations:

a. CNRS – Université Montpellier 2 – UMR 5554 – ISEM – Montpellier, France

b. Montpellier SupAgro – UMR 1334 – AGAP – Montpellier, France

*corresponding author: e-mail: nicolas.galtier@univ-montp2.fr

Abstract:

It is widely assumed that our mammalian ancestors, which lived in the Cretaceous era, were tiny animals that survived massive asteroid impacts in shelters, and evolved into modern forms after dinosaurs went extinct, 65 Mya. The small size of most Mesozoic mammalian fossils essentially supports this view. Paleontology, however, is not conclusive regarding the ancestry of extant mammals, because Cretaceous and Paleocene fossils are not easily linked to modern lineages. Here we use full-genome data to estimate the longevity and body mass of early placental mammals. Analysing 36 fully-sequenced mammalian genomes, we reconstruct two aspects of the ancestral genome dynamics, namely GC-content evolution and nonsynonymous over synonymous rate ratio. Linking these molecular evolutionary processes to life history traits in modern species, we estimate that early placental mammals had a life-span above 25 years, and a body mass above one kilogram. This is similar to current primates, cetartiodactyls or carnivores, but markedly different from mice or shrews, challenging the dominant view about mammalian origin and evolution. Our results imply that long-lived mammals existed in the Cretaceous era, and were the most successful in evolution, opening new perspectives about the conditions for survival to the Cretaceous-Tertiary crisis.

FYI.  We are back to using title links here.

Cretaceous Spider Attack Caught in Amber

The extraordinarily rare fossils are in a piece of amber that preserved this event in remarkable detail, an action that took place in the Hukawng Valley of Myanmar in the Early Cretaceous between 97-110 million years ago, almost certainly with dinosaurs wandering nearby.

Aside from showing the first and only fossil evidence of a spider attacking prey in its web, the piece of amber also contains the body of a male spider in the same web. This provides the oldest evidence of social behavior in spiders, which still exists in some species but is fairly rare. Most spiders have solitary, often cannibalistic lives, and males will not hesitate to attack immature species in the same web.

"This juvenile spider was going to make a meal out of a tiny parasitic wasp, but never quite got to it," said George Poinar, Jr., a professor emeritus of zoology at Oregon State University and world expert on insects trapped in amber. He outlined the findings in a new publication in the journal Historical Biology.

"This was a male wasp that suddenly found itself trapped in a spider web," Poinar said. "This was the wasp's worst nightmare, and it never ended. The wasp was watching the spider just as it was about to be attacked, when tree resin flowed over and captured both of them."

Spiders are ancient invertebrates that researchers believe date back some 200 million years, but the oldest fossil evidence ever found of a spider web is only about 130 million years old. An actual attack such as this between a spider and its prey caught in the web has never before been documented as a fossil, the researchers said.

Return of Man the Hunter: Meat Eating 1.5 Million Years Ago

A skull fragment unearthed by anthropologists in Tanzania shows that our ancient ancestors were eating meat at least 1.5 million years ago, shedding new light into the evolution of human physiology and brain development.

"Meat eating has always been considered one of the things that made us human, with the protein contributing to the growth of our brains," said Charles Musiba, Ph.D., associate professor of anthropology at the University of Colorado Denver, who helped make the discovery. "Our work shows that 1.5 million years ago we were not opportunistic meat eaters, we were actively hunting and eating meat."

The study was published Wednesday in the peer-reviewed journal PLOS ONE.

The two-inch skull fragment was found at the famed Olduvai Gorge in northern Tanzania, a site that for decades has yielded numerous clues into the evolution of modern humans and is sometimes called `the cradle of mankind.'

The fragment belonged to a 2-year-old child and showed signs of porotic hyperostosis associated with anemia. According to the study, the condition was likely caused by a diet suddenly lacking in meat.

"The presence of anemia-induced porotic hyperostosis…indicates indirectly that by at least the early Pleistocene meat had become so essential to proper hominin functioning that its paucity or lack led to deleterious pathological conditions," the study said. "Because fossils of very young hominin children are so rare in the early Pleistocene fossil record of East Africa, the occurrence of porotic hyperostosis in one…suggests we have only scratched the surface in our understanding of nutrition and health in ancestral populations of the deep past."

Musiba said the evidence showed that the juvenile's diet was deficient in vitamin B12 and B9. Meat seems to have been cut off during the weaning process.

"He was not getting the proper nutrients and probably died of malnutrition," he said.

The study offers insights into the evolution of hominins including Homo sapiens. Musiba said the movement from a scavenger, largely plant-eating lifestyle to a meat-eating one may have provided the protein needed to grow our brains and give us an evolutionary boost.

Hadrosaurs Had Excellent Chewing Apparatus

A team of paleontologists and engineers has found that duck-billed dinosaurs had an amazing capacity to chew tough and abrasive plants with grinding teeth more complex than those of cows, horses, and other well-known modern grazers. Their study, which is published today in the journal Science, is the first to recover material properties from fossilized teeth.

Duck-bill dinosaurs, also known as hadrosaurids, were the dominant plant-eaters in what are now Europe, North America, and Asia during the Late Cretaceous about 85 million years ago. With broad jaws bearing as many as 1,400 teeth, hadrosaurids were previously thought to have chewing surfaces similar to other reptiles, which have teeth comprised of just two tissues—enamel, a hard hypermineralized material, and orthodentine, a soft bonelike tissue. But paleontologists who study the fossilized teeth of these animals in detail suspected that they were not that simple.

"We thought for a long time that there was more going on because you could just look at the surface of the tooth and see advanced topography, which suggests that there are many different tissues present," said Mark Norell, chair of the American Museum of Natural History's Division of Paleontology and an author on the paper.

To investigate the dinosaurs' dental structure and properties in depth, Norell worked with lead author Gregory Erickson, a biology professor at Florida State University, and a team of engineers on a series of novel experiments. Erickson sectioned the fossilized teeth and made microscope slides from them. These revealed that hadrosaurids actually had six different types of dental tissues—four more than reptiles and two more than expert mammal grinders like horses, cows, and elephants. Using a technique called nanoindentation, in which a diamond-tipped probe is indented and/or drawn across the fossilized teeth to mimic the grinding of abrasive food, the researchers determined the differential hardness and wear rates of the dental tissues.

Erickson, who describes hadrosaurid dinosaurs as "walking pulp mills," said, "We were stunned to find that the mechanical properties of the teeth were preserved after 70 million years of fossilization." He went on to comment that "if you put these teeth back into a living dinosaur they would function perfectly."

In addition to the four dental tissues found in mammals—enamel, orthodentine, secondary dentine that helps prevent cavities, and coronal cementum that supports the teeth's crests—the hadrosaurid teeth include giant tubules and a thick mantle dentine. These extra tissues are thought to provide additional prevention against abscesses. Also unlike mammalian teeth, the dental tissue distribution in hadrosaurids greatly varied in each tooth.

Together, these characteristics suggest that hadrosaurids evolved the most advanced grinding capacity known in vertebrate animals, which might have led to their extensive diversification.

"Duck-bills' advanced tissue modification appears to have allowed them to radiate into specialized ecological niches where they ate extremely tough plants like fern, horsetail, and ground cover that were not as easy for dinosaurs with shearing teeth to eat," Norell said. "Their complex dentition could have played a major role in keeping them on the planet for nearly 35 million years."

Pegomastax africanus: A Heterodontosaur with Bristles?

A new, tiny dinosaur with vampire-like fangs devoured ... plants?

So says a new study of Pegomastax africanus, a 2-foot-long (0.6-meter-long) heterodontosaur that lived about 200 million years ago.

[...]

Covered in porcupine-like quills and sporting a blunt, parrot-like beak, P. africanus would've looked like a "strange little bird," said Sereno, a paleontologist with the University of Chicago.

[...]

While preparing a comprehensive analysis of the little-known heterodontosaurs, Sereno identified P. africanus from fossils at Harvard University, which had been collected in South Africa in the 1960s.

To find out what the newfound dinosaur did with its sharp fangs, Sereno then reassembled P. africanus' jaw and teeth. He compared the reconstruction to jaws and teeth of both meat-eating dinosaurs and modern plant-eating mammals with fangs.

Sereno discovered that P. africanus' fangs were very similar to those of fanged deer and peccaries, which use their fangs in self-defense and competition for mates, he said.

Supporting this theory, microscopic analysis of P. africanus' fang enamel revealed wear and breakage consistent with sparring.

The researcher suggested too that the cheek teeth in P. africanus' upper and lower jaws worked like self-sharpening scissors for shearing plant parts, as detailed in the study, published online Wednesday in the journal ZooKeys.

Link to Nat Geo article.  Link to paper.

Going to read the paper.  The connection to Zookeys seems to have a craaaazy slow connection for downloading the PDF.  9.8kbps would have been great for ftp in the days of the early 90s.  That was 20 years ago.  yikes.

I'm curious where he gets the quill covering from.  The fossil?  Guessing?

Update:  I won't be able to tell for a while.  It looks like the paper is mangled.  The PDFs are damaged and the HTML version of the paper is cut off mid sentence.

Europa's Under Ice Ocean is not Near the Surface

Europa, the enigmatic moon of Jupiter, is believed to be home to a subsurface ocean of liquid water. However, future missions to explore Europa's ocean may need to dig deep. Research suggests that water does not stay in a liquid state near Europa's surface for longer than a few tens of thousands of years - the blink of an eye in geological terms. Klara Kalousova will present this work at the European Planetary Science Congress in Madrid on Tuesday 25 September 2012.

Europa is mainly made from rock and iron, with a water shell around 100km deep beneath a crust of solid ice. The ocean is warmed sufficiently to maintain its liquid state by heat produced as a by-product of gravitational pulling to-and-fro from Jupiter.

Pockets of liquid water could be tantalisingly close to the surface. However, Kalousova, from the University of Nantes and Charles University in Prague, believes these would be short-lived. She explains, "A global water ocean may be present, but relatively deep below the surface - around 25 to 50km. There could be areas of liquid water at much shallower depths, say around 5km, but these would only exist for a few tens of thousands of years before migrating downwards."

Kalousova reached these conclusions by mathematically modelling mixtures of liquid water and solid ice under different conditions. She found that due to factors such as density and viscosity differences, liquid water migrates rapidly downwards through partially molten ice and eventually reaches the subsurface ocean.

This is a model. I do not know the level of confidence that ought to be attached to it.

Medieval Warm Period Was Not Uniformly Warm

Summers on the Norwegian archipelago of Svalbard are now warmer than at any other time in the last 1,800 years, including during medieval times when parts of the northern hemisphere were as hot as, or hotter, than today, according to a new study in the journal Geology.

"The Medieval Warm Period was not as uniformly warm as we once thought--we can start calling it the Medieval Period again," said the study's lead author, William D'Andrea, a climate scientist at Columbia University's Lamont-Doherty Earth Observatory. "Our record indicates that recent summer temperatures on Svalbard are greater than even the warmest periods at that time."

The naturally driven Medieval Warm Period, from about 950 to 1250, has been a favorite time for people who deny evidence that humans are heating the planet with industrial greenhouse gases. But the climate reconstruction from Svalbard casts new doubt on that era's reach, and undercuts skeptics who argue that current warming is also natural. Since 1987, summers on Svalbard have been 2 degrees to 2.5 degrees C (3.6 to 4.5 degrees F) hotter than they were there during warmest parts of the Medieval Warm Period, the study found.

Researchers produced the 1,800 year climate record by analyzing levels of unsaturated fats in algae buried in the sediments of Kongressvatnet lake, in western Svalbard. In colder water, algae make more unsaturated fats, or alkenones; in warmer water, they produce more saturated fats. Like pages in a book, the unsaturation level of fats can provide a record of past climate. So far, most Arctic climate records have come from ice cores that preserve only annual layers of cold-season snowfall, and thus cold-season temperatures. But lake sediments, with their record of summertime temperatures, can tell scientists how climate varied the rest of the year and in places where ice sheets are absent.

"We need both ice core and lake sediment records," said Elisabeth Isaksson, a glaciologist at the Norwegian Polar Institute who was not involved in the study. "Here, Billy has found something that tells a different, more detailed story."

In looking at how summers on Svalbard varied, researchers also discovered that the region was not particularly cold during another recent anomalous period--the "Little Ice Age" of the 18th and 19th centuries, when glaciers on Svalbard surged to their greatest extent in the last 10,000 years and glaciers in many parts of Western Europe also grew. They suggest that more snow, rather than colder temperatures, may have fed the growth of Svalbard glaciers.

Evidence from tree rings and ice cores shows that southern Greenland and parts of North America were warmer from 950 to 1250 than today, with the Vikings taking advantage of ice-free waters to settle Greenland. Some regions also saw prolonged drought, including California, Nevada and the Mississippi Valley, leading some scientists to coin the term Medieval Climate Anomaly to emphasize the extreme shift in precipitation rather than temperature. A natural increase in solar radiation during this time was responsible for warming parts of the northern hemisphere, with a rise in volcanic activity from 1100 to 1260 causing milder winters, University of Massachusetts scientist Ray Bradley explained in a 2003 Perspective piece in Science. Bradley is a co-author of the Svalbard lake sediment study.

Western Svalbard began to gradually warm in 1600, the researchers found, when the northern arm of the Gulf Stream, known as the West Spitsbergen Current, may have brought more tropical water to the region. In 1890, the warming began to accelerate, with researchers attributing most of the warming since about 1960 to rising industrial greenhouse gas levels. Ice cores from Svalbard, by contrast, show a slight cooling over the last 1,800 years. The conflicting evidence suggests that temperatures may have fluctuated more sharply between winter and summer, said Anne Hormes, a quaternary geologist at the University Centre in Svalbard who was not involved in the study.

D'Andrea and his colleagues dated their lake cores by analyzing grains of glass spewed by volcanoes hundreds of miles away in Iceland. Those past eruptions-- Snæfellsjökull in 170, Hekla in 1104 and Öræfajökull in 1362--all left unique chemical time markers on Svalbard's lake sediments. "We know fairly precisely when these eruptions occurred, which is rare in the geologic record," said study co-author Nicholas Balascio, a scientist at University of Massachusetts, Amherst.

Gosh. Climate complicated? ;)

Southwestern Forests Threatened by Climate Change

Combine the tree-ring growth record with historical information, climate records, and computer-model projections of future climate trends, and you get a grim picture for the future of trees in the southwestern United States. That's the word from a team of scientists from Los Alamos National Laboratory, the U.S. Geological Survey, the University of Arizona, and other partner organizations.

If the Southwest is warmer and drier in the near future, widespread tree death is likely and would cause substantial changes in the distribution of forests and of species, the researchers report this week in the journal Nature Climate Change.

Southwestern forests grow best when total winter precipitation is high combined with a summer and fall that aren't too hot and dry.

The team developed a Forest Drought-Stress Index that combines the amount of winter precipitation, late summer and fall temperatures, and late summer and fall precipitation into one number.

"The new 'Forest Drought-Stress Index' that Williams devised from seasonal precipitation and temperature-related variables matches the records of changing forest conditions in the Southwest remarkably well," said co-author Thomas W. Swetnam, director of the UA Laboratory of Tree-Ring Research.

"Among all climate variables affecting trees and forests that have ever been studied, this new drought index has the strongest correlation with combined tree growth, tree death from drought and insects, and area burned by forest fires that I have ever seen."

A. Park Williams of Los Alamos National Laboratory in New Mexico is the lead author of the paper, "Temperature as a potent driver of regional forest drought stress and tree mortality." Six of the paper's 15 authors are at the UA. A complete list of authors is at the bottom of this release.

To figure out which climate variables affect forests, the researchers aligned some 13,000 tree core samples with known temperature and moisture data. The team also blended in events known from tree-ring, archaeological and other paleorecords, such as the late 1200s megadrought that drove the ancient Pueblo Indians out of longtime settlements such as those at Mesa Verde, Colo.

By comparing the tree-ring record to climate data collected in the Southwest since the late 1800s, the scientists identified two climate variables that estimate annual southwestern tree-growth variability with exceptional accuracy: total winter precipitation and average summer-fall atmospheric evaporative demand, a measure of the overall dryness of the environment.

Williams said, "Atmospheric evaporative demand is primarily driven by temperature. When air is warmer, it can hold more water vapor, thus increasing the pace at which soil and plants dry out. The air literally sucks the moisture out of the soil and plants."

Finding that summer-fall atmospheric evaporative demand is just as important as winter precipitation has critical implications for the future of southwestern forests, he said.

These trends, the researchers noted, are already occurring in the Southwest, where temperatures generally have been increasing for the past century and are expected to continue to do so because of accumulating greenhouse gases in the atmosphere.

There still will be wet winters, but increased frequency of warmer summers will put more stress on trees and limit their growth after wet winters, the study reports.

"We can use the past to learn about the future," Williams said. "For example, satellite fire data from the past 30 years show that there has been a strong and exponential relationship between the regional tree-ring drought-stress record and the area of southwestern forests killed by wildfire each year. This suggests that if drought intensifies, we can expect forests not only to grow more slowly, but also to die more quickly."

The study points out that very large and severe wildfires, bark-beetle outbreaks and a doubling of the proportion of dead trees in response to early 21st-century warmth and drought conditions are evidence that a transition of southwestern forest landscapes toward more open and drought-tolerant ecosystems may already be underway.

And while 2000s drought conditions have been severe, the regional tree-ring record indicates there have been substantially stronger megadrought events during the past 1,000 years.

A Mysterious Seed Fern From the Upper Permian of China

Recently, a mysterious seed fern, Lepidopteris baodensis sp. nov., dating to more than 251 million years ago (Ma), was discovered at the Baijiagou of Baode, Shanxi, China, from the Upper Permian Sunjiagou Formation. This discovery completely changed the understanding of the stratigraphic distribution of the genus Lepidopteris in China and promoted the taxonomic study of late Paleozoic plants.

Since Schimper erected the genus Lepidopteris in 1869, its epidermal structure of subepidermal swellings (formerly called "blisters") had long been an unsolved mystery. Excitingly, we found subepidermal swellings not only on the lower surfaces of the ultimate rachis and midrib, but also on the lower surfaces of secondary veins. In addition, the unique epidermal structures of subepidermal swellings on the ultimate rachis, midrib and secondary veins were revealed. The epidermis of a subepidermal swelling on an ultimate rachis was composed of ordinary epidermal cells and stomatal apparatuses forming longitudinal rows and numerous groups. The epidermal cells and stomatal apparatuses in each group were set in a concentric pattern. The epidermis of a subepidermal swelling on the midrib was also composed of ordinary epidermal cells and stomatal apparatuses that formed only 3𔃂 groups, and were set in a concentric pattern. The epidermis of a subepidermal swelling on a secondary vein was composed of ordinary epidermal cells and stomatal apparatuses, forming a concentric pattern. Because, unlike the lower surface, the upper surface lacked subepidermal swellings, the difference in epidermal structures between the upper and lower surfaces is remarkable. This situation is very rare in plants.

[...]

In 2004, the noted paleontologists and biostratigraphers Rong Jiayu (Academician Professor of NIGPAS) and Fang Zongjie (Professor of NIGPAS) pointed out in the book "Mass Extinction and Recovery" that the Earth experienced a mass extinction and recovery between the Late Permian and the Triassic, traced back to 260 Ma. The climate became extremely hot and arid at the end of the Permian. The mass extinction, which was the largest in Earth's history, destroyed most terrestrial and marine ecosystems. On land, coal-forming floras, represented by Lepidodendron and Cordaites, went extinct. The Euramerican, Cathaysian, Gondwanan and Angaran floras disappeared, and a new flora, represented by Pleuromeia, flourished after the disaster. The recovery of coal-forming floras on a large scale did not begin until the Late Triassic.

Although the terrestrial and marine ecosystems of the Earth experienced their largest mass extinction in the Late Permian, the seed fern Lepidopteris became an important element of remnant vegetation and persisted through the Triassic. Thus, the study of Lepidopteris plays a very important role in understanding this mass extinction and recovery.

Which adaptations allowed Lepidopteris to survive the harsh environment? The authors believe its persistence was probably related to the subepidermal swellings, which were special tissues unique to Lepidopteris. Based on analysis of the cuticle, the lower surfaces of the ultimate rachis, midrib and secondary veins, which are related to conducting tissues, were covered with subepidermal swellings. These subepidermal swellings were probably small water storage features that absorbed water during high flows in conducting tissues and released it during low flows, like an irrigation system. In this way, Lepidopteris, a seed fern that originally needed much water to live, probably survived the hot and arid environment. Of course, subepidermal swellings are likely to have had other functions as well.

OY! ON STEROIDS! Supercomputers on the Moon!

The proposal by USC doctoral student Ouliang Chang, presented last week at the the American Institute of Aeronautics and Astronautics (AIAA) Space 2012 conference, proposes a sci-fi solution to a real-world data overload challenge. NASA controls its interplanetary satellite missions through the Deep Space Network (DSN), a ring of huge satellite dishes in California, Spain and Australia. But the massive amounts of data traffic being sent to NASA is growing at a rate the current set-up can’t handle. Chang has proposed that one way to ease the strain would be to build a supercomputer and accompanying radio dishes on the moon.

This is...such a bad idea I cannot even start. You know what. I will. Though on the official GLXP blog for my team. If there was ever someone that has the background to comment, it'd be me.  I think this counts as my He3 for lunar applications.

3D Model of a Carboniferous Arthopod

Link.

Archaen Age Microbial Colonization of Terrestrial Environments

There is evidence that some microbial life had migrated from the Earth's oceans to land by 2.75 billion years ago, though many scientists believe such land-based life was limited because the ozone layer that shields against ultraviolet radiation did not form until hundreds of millions years later.

But new research from the University of Washington suggests that early microbes might have been widespread on land, producing oxygen and weathering pyrite, an iron sulfide mineral, which released sulfur and molybdenum into the oceans.

"This shows that life didn't just exist in a few little places on land. It was important on a global scale because it was enhancing the flow of sulfate from land into the ocean," said Eva Stüeken, a UW doctoral student in Earth and space sciences.

In turn, the influx of sulfur probably enhanced the spread of life in the oceans, said Stüeken, who is the lead author of a paper presenting the research published Sunday (Sept. 23) in Nature Geoscience. The work also will be part of her doctoral dissertation.

Sulfur could have been released into sea water by other processes, including volcanic activity. But evidence that molybdenum was being released at the same time suggests that both substances were being liberated as bacteria slowly disintegrated continental rocks, she said.

If that is the case, it likely means the land-based microbes were producing oxygen well in advance of what geologists refer to as the "Great Oxidation Event" about 2.4 billion years ago that initiated the oxygen-rich atmosphere that fostered life as we know it.

In fact, the added sulfur might have allowed marine microbes to consume methane, which could have set the stage for atmospheric oxygenation. Before that occurred, it is likely large amounts of oxygen were destroyed by reacting with methane that rose from the ocean into the air.

"It supports the theory that oxygen was being produced for several hundred million years before the Great Oxidation Event. It just took time for it to reach higher concentrations in the atmosphere," Stüeken said.

The research examined data on sulfur levels in 1,194 samples from marine sediment formations dating from before the Cambrian period began about 542 million years ago. The processes by which sulfur can be added or removed are understood well enough to detect biological contributions, the researchers said.

Link.

Khoe-San People are VERY Genetically Distinct

Genetically, culturally and ethically the Khoe-San have something special to add to this world. The importance of this study is to put the Khoe and San heritage in the right place in history and this research will provide a genetic backdrop for future studies - Mattias Jakobsson.

The largest genomic study ever conducted among Khoe and San groups reveals that these groups from southern Africa are descendants of the earliest diversification event in the history of all humans - some 100 000 years ago, well before the 'out-of-Africa' migration of modern humans.

Some 220 individuals from different regions in southern Africa participated in the research that led to the analysis of around 2.3 million DNA variants per individual – the biggest ever.

The research was conducted by a group of international scientists, including Professor Himla Soodyall from the Human Genomic Diversity and Disease Research Unit in the Health Faculty at the University of the Witwatersrand in Johannesburg.

Entitled Genomic variation in seven Khoe-San groups reveals adaptation and complex African history...

[...]

"The deepest divergence of all living people occurred some 100 000 years ago, well before modern humans migrated out of Africa and about twice as old as the divergences of central African Pygmies and East African hunter-gatherers and from other African groups," says lead author Dr Carina Schlebusch, a Wits University PhD-graduate now conducting post-doctoral research at Uppsala University in Sweden.

Link. Paper link later.

We Have Data Now: Antarctica's Ice Flows Influenced Greatly by Warming Waters

Fast-flowing and narrow glaciers have the potential to trigger massive changes in the Antarctic ice sheet and contribute to rapid ice-sheet decay and sea-level rise, a new study has found.

Research results published in the journal Proceedings of the National Academy of Sciences reveal in more detail than ever before how warming waters in the Southern Ocean are connected intimately with the movement of massive ice-sheets deep in the Antarctic interior.

"It has long been known that narrow glaciers on the edge of the Antarctica act as discrete arteries termed ice streams, draining the interior of the ice sheet," says Dr Chris Fogwill, an author of the study and an ARC Future Fellow with the UNSW Climate Change Research Centre.

"However, our results have confirmed recent observations suggesting that ocean warming can trigger increased flow of ice through these narrow corridors. This can cause inland sectors of the ice-sheet - some larger than the state of Victoria - to become thinner and flow faster."

The researchers, led by Dr Nicholas Golledge from Victoria University of Wellington, New Zealand, tested high-resolution model simulations against reconstructions of the Antarctic ice sheet from 20,000 years ago, during the last glacial maximum.

They used a new model, capable of resolving responses to ice-streams and other fine- scale dynamic features that interact over the entire ice sheet. This had not previously been possible with existing models. They then used this data to analyse the effects of a warming ocean over time.

The results showed that while glacier acceleration triggered by ocean warming is relatively localized, the extent of the resultant ice-sheet thinning is far more widespread. This observation is particularly important in light of recently observed dynamic changes at the margins of Antarctica. It also highlighted areas that are more susceptible than others to changes in ocean temperatures.

The glaciers that responded most rapidly to warming oceans were found in the Weddell Sea, the Admundsen Sea, the central Ross Sea and in the Amery Trough.

The finding is important because of the enormous scale and potential impact the Antarctic ice sheets could have on sea-level rise if they shift rapidly, says Fogwill. "To get a sense of the scale, the Antarctic ice sheet is 3km deep - three times the height of the Blue Mountains in many areas - and it extends across an area that is equivalent to the distance between Perth and Sydney.

"Despite its potential impact, Antarctica's effect on future sea level was not fully included in the last IPCC report because there was insufficient information about the behaviour of the ice sheet. This research changes that. This new, high-resolution modelling approach will be critical to improving future predictions of Antarctica's contribution to sea level over the coming century and beyond."

Link.

Did a Genetic Mutation Allow Anatomically Modern Homo sapiens to Spread?

A genetic mutation that occurred thousands of years ago might be the answer to how early humans were able to move from central Africa and across the continent in what has been called "the great expansion," according to new research from Wake Forest Baptist Medical Center.

By analyzing genetic sequence variation patterns in different populations around the world, three teams of scientists from Wake Forest Baptist, Johns Hopkins University School of Medicine and the University of Washington School of Medicine, Seattle, demonstrated that a critical genetic variant arose in a key gene cluster on chromosome 11, known as the fatty acid desaturase cluster or FADS, more than 85,000 years ago. This variation would have allowed early humans to convert plant-based polyunsaturated fatty acids (PUFAs) to brain PUFAs necessary for increased brain size, complexity and function. The FADS cluster plays a critical role in determining how effectively medium-chain PUFAs found in plants are converted to the long-chain PUFAs found in the brain.

This research is published online today in PLOS One.

Archeological and genetic studies suggest that homo sapiens appeared approximately 180,000 years ago, but stayed in one location around bodies of water in central Africa for almost 100,000 years. Senior author Floyd H. "Ski" Chilton, Ph.D., professor of physiology and pharmacology and director of the Center for Botanical Lipids and Inflammatory Disease Prevention at Wake Forest Baptist, and others have hypothesized that this location was critical, in part, because early humans needed large amounts of the long-chain PUFA docosahexaenoic acid (DHA), which is found in shellfish and fish, to support complex brain function.

"This may have kept early humans tethered to the water in central Africa where there was a constant food source of DHA," Chilton said. "There has been considerable debate on how early humans were able to obtain sufficient DHA necessary to maintain brain size and complexity. It's amazing to think we may have uncovered the region of genetic variation that arose about the time that early humans moved out of this central region in what has been called the 'great expansion.'"

Once this trait arose, the study shows that it was under intense selective pressure and thus rapidly spread throughout the population of the entire African continent. "The power of genetics continually impresses me, and I find it remarkable that we can make inferences about things that happened tens of thousands of years ago by studying patterns of genetic variation that exist in contemporary populations," said Joshua M. Akey, Ph.D., lead scientist at the University of Washington.

This conversion meant that early humans didn't have to rely on just one food source, fish, for brain growth and development. This may have been particularly important because the genetic variant arose before organized hunting and fishing could have provided more reliable sources of long-chain PUFAs, Akey said.

To investigate the evolutionary forces shaping patterns of variation in the FADS gene cluster in geographically diverse populations, the researchers analyzed 1,092 individuals representing 15 different human populations that were sequenced as part of the 1000 Genome Project and 1,043 individuals from 52 populations from the Human Genome Diversity Panel database. They focused on the FADS cluster because they knew those genes code for the enzymatic steps in long-chain PUFA synthesis that are the least efficient.

Chilton said the findings were possible because of the collaboration of internationally recognized scientists from three distinct and diverse disciplines – fatty acid biochemistry (Wake Forest Baptist), statistical genetics (Johns Hopkins) and population genetics (University of Washington). This new information builds on Chilton's 2011 research findings published in BMC Genetics that showed how people of African descent have a much higher frequency of the gene variants that convert plant-based medium-chain omega-6 PUFAs found in cooking oils and processed foods to long-chain PUFAs that cause inflammation. Compared to Caucasians, African Americans in the United States have much higher rates of hypertension, type 2 diabetes, stroke, coronary heart disease and certain types of cancer. "The current observation provides another important clue as to why diverse racial and ethnic populations likely respond differently to the modern western diet," Chilton said.

Link.

Lowest Low: Arctic Ice Cap Sets Lowest Record of Extent

The frozen cap of the Arctic Ocean appears to have reached its annual summertime minimum extent and broken a new record low on Sept. 16, the National Snow and Ice Data Center (NSIDC) has reported. Analysis of satellite data by NASA and the NASA-supported NSIDC at the University of Colorado in Boulder showed that the sea ice extent shrunk to 1.32 million square miles (3.41 million square kilometers).

The new record minimum measures almost 300,000 square miles less than the previous lowest extent in the satellite record, set in mid-September 2007, of 1.61 million square miles (4.17 million square kilometers). For comparison, the state of Texas measures around 268,600 square miles.

NSIDC cautioned that, although Sept. 16 seems to be the annual minimum, there's still time for winds to change and compact the ice floes, potentially reducing the sea ice extent further. NASA and NSIDC will release a complete analysis of the 2012 melt season next month, once all data for September are available.

Arctic sea ice cover naturally grows during the dark Arctic winters and retreats when the sun re-appears in the spring. But the sea ice minimum summertime extent, which is normally reached in September, has been decreasing over the last three decades as Arctic ocean and air temperatures have increased. This year's minimum extent is approximately half the size of the average extent from 1979 to 2000. This year's minimum extent also marks the first time Arctic sea ice has dipped below 4 million square kilometers.

"Climate models have predicted a retreat of the Arctic sea ice; but the actual retreat has proven to be much more rapid than the predictions," said Claire Parkinson, a climate scientist at NASA Goddard Space Flight Center, Greenbelt, Md. "There continues to be considerable inter-annual variability in the sea ice cover, but the long-term retreat is quite apparent."

The thickness of the ice cover is also in decline.

"The core of the ice cap is the perennial ice, which normally survived the summer because it was so thick", said Joey Comiso, senior scientist with NASA Goddard. "But because it's been thinning year after year, it has now become vulnerable to melt".

The disappearing older ice gets replaced in winter with thinner seasonal ice that usually melts completely in the summer.

Link.

Textron's Flying Bomb

 Link.

30 minute loiter time?  The article says it has a max speed of 60 mph (96km/h).  I doubt that it has a 30 minute loiter with 60 mph the entire time.  Even so, if its doing 20 mph for 30 minutes, you have infantry with a range of 10 miles.  Even more interesting would be if you could pack the launch tubes into something like a M113 as vertical launch tubes.  Esp if they could have a shape charge version of the warhead.  I wonder how many they could pack in it?

Did the Quartenary Start with a Bang? An Asteroid Bang?

When a huge meteor collided with Earth about 2.5 million years ago and fell into the southern Pacific Ocean it not only could have generated a massive tsunami but also may have plunged the world into the Ice Ages, a new study suggests.

A team of Australian researchers says that because the Eltanin meteor – which was up to two kilometres across - crashed into deep water, most scientists have not adequately considered either its potential for immediate catastrophic impacts on coastlines around the Pacific rim or its capacity to destabilise the entire planet's climate system.

"This is the only known deep-ocean impact event on the planet and it's largely been forgotten because there's no obvious giant crater to investigate, as there would have been if it had hit a landmass," says Professor James Goff, lead author of a forthcoming paper in the Journal of Quaternary Science. Goff is co-director of UNSW's Australia-Pacific Tsunami Research Centre and Natural Hazards Research Laboratory.

"But consider that we're talking about something the size of a small mountain crashing at very high speed into very deep ocean, between Chile and Antarctica. Unlike a land impact, where the energy of the collision is largely absorbed locally, this would have generated an incredible splash with waves literally hundreds of metres high near the impact site.

"Some modelling suggests that the ensuing mega-tsunami could have been unimaginably large – sweeping across vast areas of the Pacific and engulfing coastlines far inland. But it also would have ejected massive amounts of water vapour, sulphur and dust up into the stratosphere. "The tsunami alone would have been devastating enough in the short term, but all that material shot so high into the atmosphere could have been enough to dim the sun and dramatically reduce surface temperatures. Earth was already in a gradual cooling phase, so this might have been enough to rapidly accelerate and accentuate the process and kick start the Ice Ages."

In the paper, Goff and colleagues from UNSW and the Australian Nuclear Science and Technology Organisation, note that geologists and climatologists have interpreted geological deposits in Chile, Antarctica, Australia, and elsewhere as evidence of climatic change, marking the start of the Quaternary period. An alternative interpretation is that some or all of these deposits may be the result of mega-tsunami inundation, the study suggests.

"There's no doubt the world was already cooling through the mid and late Pliocene," says co-author Professor Mike Archer. "What we're suggesting is that the Eltanin impact may have rammed this slow-moving change forward in an instant - hurtling the world into the cycle of glaciations that characterized the next 2.5 million years and triggered our own evolution as a species.

"As a 'cene' changer - that is, from the Pliocene to Pleistocene - Eltanin may have been overall as significant as the meteor that took out the non-flying dinosaurs 65 million years ago. We're urging our colleagues to carefully reconsider conventional interpretations of the sediments we're flagging and consider whether these could be instead the result of a mega-tsunami triggered by a meteor."

Link.

I suspect that the impact needs to be better constrained for this to be taken past the point of a hypothesis. I find a number of places (like the UCSC image above) that would place the impact at different time periods which would kill the causality.

Supporting the Arts...of Friends

My Son With Whom I Am Pleased

Introducing the J-21: China's Second Stealth Fighter

From the China Defense Blog.

Ruminations on the implications at The Dew Line, Danger Room and Ares.

Son and Neighbor

Both of whom have the same birthday.  How likely is that?

Stunning Interpolated Video of Curiosity's Landing

First Genetic Test for Austism

A team of Australian researchers, led by University of Melbourne has developed a genetic test that is able to predict the risk of developing Autism Spectrum Disorder, ASD.

Lead researcher Professor Stan Skafidas, Director of the Centre for Neural Engineering at the University of Melbourne said the test could be used to assess the risk for developing the disorder.

"This test could assist in the early detection of the condition in babies and children and help in the early management of those who become diagnosed," he said.

"It would be particularly relevant for families who have a history of Autism or related conditions such as Asperger's Syndrome," he said.

Autism affects around one in 150 births and is characterized by abnormal social interaction, impaired communication and repetitive behaviours.

The test correctly predicted ASD with more than 70 per cent accuracy in people of central European descent. Ongoing validation tests are continuing including the development of accurate testing for other ethnic groups.

Clinical neuropsychologist, Dr Renee Testa from the University of Melbourne and Monash University, said the test would allow clinicians to provide early interventions that may reduce behavioural and cognitive difficulties that children and adults with ASD experience.

"Early identification of risk means we can provide interventions to improve overall functioning for those affected, including families," she said.

A genetic cause has been long sought with many genes implicated in the condition, but no single gene has been adequate for determining risk.

Using US data from 3,346 individuals with ASD and 4,165 of their relatives from Autism Genetic Resource Exchange (AGRE) and Simons Foundation Autism Research Initiative (SFARI), the researchers identified 237 genetic markers (SNPs) in 146 genes and related cellular pathways that either contribute to or protect an individual from developing ASD.

Senior author Professor Christos Pantelis of the Melbourne Neuropsychiatry Centre at the University of Melbourne and Melbourne Health said the discovery of the combination of contributing and protective gene markers and their interaction had helped to develop a very promising predictive ASD test.

The test is based on measuring both genetic markers of risk and protection for ASD. The risk markers increase the score on the genetic test, while the protective markers decrease the score. The higher the overall score, the higher the individual risk.

Link.

70% is pretty good but needs improvement.  The fact that they have a genetic test with that much accuracy is a big hint on what the real causes are rather than people's wishful thinking.

Planets Can Form in the Galactic Center

At first glance, the center of the Milky Way seems like a very inhospitable place to try to form a planet. Stars crowd each other as they whiz through space like cars on a rush-hour freeway. Supernova explosions blast out shock waves and bathe the region in intense radiation. Powerful gravitational forces from a supermassive black hole twist and warp the fabric of space itself.

Yet new research by astronomers at the Harvard-Smithsonian Center for Astrophysics shows that planets still can form in this cosmic maelstrom. For proof, they point to the recent discovery of a cloud of hydrogen and helium plunging toward the galactic center. They argue that this cloud represents the shredded remains of a planet-forming disk orbiting an unseen star.

"This unfortunate star got tossed toward the central black hole. Now it's on the ride of its life, and while it will survive the encounter, its protoplanetary disk won't be so lucky," said lead author Ruth Murray-Clay of the CfA. The results are appearing in the journal Nature.

The cloud in question was discovered last year by a team of astronomers using the Very Large Telescope in Chile. They speculated that it formed when gas streaming from two nearby stars collided, like windblown sand gathering into a dune.

Murray-Clay and co-author Avi Loeb propose a different explanation. Newborn stars retain a surrounding disk of gas and dust for millions of years. If one such star dived toward our galaxy's central black hole, radiation and gravitational tides would rip apart its disk in a matter of years.

They also identify the likely source of the stray star - a ring of stars known to orbit the galactic center at a distance of about one-tenth of a light-year. Astronomers have detected dozens of young, bright O-type stars in this ring, which suggests that hundreds of fainter Sun-like stars also exist there. Interactions between the stars could fling one inward along with its accompanying disk.

Although this protoplanetary disk is being destroyed, the stars that remain in the ring can hold onto their disks. Therefore, they may form planets despite their hostile surroundings.

As the star continues its plunge over the next year, more and more of the disk's outer material will be torn away, leaving only a dense core. The stripped gas will swirl down into the maw of the black hole. Friction will heat it to high enough temperatures that it will glow in X-rays.

Link.

The Topography of Vesta

via NASA.

After Three Years...

Someone...

...finally...

...got a haircut.

And Dad couldn't be happier.  Now if he'd stop messing up his hair long enough for a picture to be taken!

Those pictures were taken less than a week apart, btw.  Amazing what a haircut can do!

More Biotic Influence on Climate: Deforestation Has Impact on Tropical Rainfall

Deforestation can have a significant effect on tropical rainfall, new research confirms. The findings have potentially devastating impacts for people living in and near the Amazon and Congo forests.

A team from the University of Leeds and the NERC Centre for Ecology & Hydrology found that for the majority of the Earth's tropical land surface, air passing over extensive forests produces at least twice as much rain as air passing over little vegetation. In some cases these forests increased rainfall thousands of kilometres away.

By combining observational data with predictions of future deforestation, the researchers estimate that destruction of tropical forests would reduce rain across the Amazon basin by up to a fifth (21 per cent) in the dry season by 2050. The study is published today in Nature.

Lead author Dr Dominick Spracklen from the School of Earth and Environment at the University of Leeds said: "We were surprised to find that this effect occurs strongly across more than half of the tropics. We found that the Amazon and Congo forests maintain rainfall over the periphery of the forest basins - regions where large numbers of people live and rely on rainfall for their livelihoods.

"Our study implies that deforestation of the Amazon and Congo forests could have catastrophic consequences for the people living thousands of kilometres away in surrounding countries."

Scientists have debated whether vegetation increases rainfall for hundreds of years. It is well established that plants put moisture back in the air through their leaves by a process known as evapotranspiration, but the quantity and geographical reach of rainfall generated by large forests has – until now – been unclear. While there is plenty of anecdotal evidence that forests significantly increase rainfall, until now there has been a lack of observational evidence.

The team used newly available NASA satellite observations of rainfall and vegetation, along with a model which predicts atmospheric wind flow patterns, to explore the impact of the Earth's tropical forests.

"We looked at what had been happening to the air over previous days – where it came from and how much forest it had travelled over," Dr Spracklen said.

To understand the relationship in detail, they investigated the journey of air masses arriving over different parts of the forest, to see the cumulative amount of leaf cover the air had moved over during the previous ten days, not just the amount of vegetation it was over when it rained. This showed that the more vegetation the air had travelled over, the more moisture it carried and more rain was produced.

Dr Stephen Arnold from the University of Leeds, a co-author on the paper, said: "The observations show that to understand how forests impact rainfall, we need to account for how air has interacted with vegetation during its journey through the atmosphere often over thousands of kilometres. This has significant implications for how policy makers should consider the environmental impacts of deforestation, since its effects on rainfall patterns may be felt not only locally, but on a continental scale.

"

link.

This nicely dovetails with the recent findings about the Maya.

Ok You Geo Types: What Is This?

Ignore, for the moment, where it comes from.  What does it look like to you?

Was the KT Extinction Actually Two Extinction Events?

The most-studied mass extinction in Earth history happened 65 million years ago and is widely thought to have wiped out the dinosaurs. New University of Washington research indicates that a separate extinction came shortly before that, triggered by volcanic eruptions that warmed the planet and killed life on the ocean floor.

The well-known second event is believed to have been triggered by an asteroid at least 6 miles in diameter slamming into Mexico's Yucatán Peninsula. But new evidence shows that by the time of the asteroid impact, life on the seafloor – mostly species of clams and snails – was already perishing because of the effects of huge volcanic eruptions on the Deccan Plateau in what is now India.

"The eruptions started 300,000 to 200,000 years before the impact, and they may have lasted 100,000 years," said Thomas Tobin, a UW doctoral student in Earth and space sciences.

The eruptions would have filled the atmosphere with fine particles, called aerosols, that initially cooled the planet but, more importantly, they also would have spewed carbon dioxide and other greenhouse gases to produce long-term warming that led to the first of the two mass extinctions.

"The aerosols are active on a year to 10-year time scale, while the carbon dioxide has effects on a scale of hundreds to tens of thousands of years," Tobin said.

During the earlier extinction it was primarily life on the ocean floor that died, in contrast to the later extinction triggered by the asteroid impact, which appeared to kill many more free-swimming species.

"The species in the first event are extinct but the groups are all recognizable things you could find around on a beach today," he said.

Tobin is the lead author of a paper in the journal Palaeogeography, Palaeoclimatology, Palaeoecology that documents results of research conducted in a fossil-rich area on Seymour Island, off the Antarctic Peninsula.

That particular area has very thick sediment deposits and, for a given interval of time, might contain 10 times more sediment as the well-known Hell Creek Formation in Montana. That means scientists have much greater detail as they try to determine what was happening at the time, Tobin said.

The researchers took small surface core samples from rocks and fossils in the Antarctic sediment and used a method called magnetostratigraphy, employing known changes over time in Earth's magnetic field to determine when the fossils were deposited. The thicker sediment allowed dating to be done more precisely.

"I think the evidence we have from this location is indicative of two separate events, and also indicates that warming took place," Tobin said.

Link.

I have been reading this paper for a bit now and had been planning on doing a write up for some time.  I am going to make a couple very quick comments here, but they ought to be expanded on in a dedicated post.

First, good for Tobin for looking for different signatures for the possible different extinctions!  I don't know ANYONE who has suggested doing that!  ;)

Second, its a bit of caution.  He has a single site that suggests this.  The evidence definitely supports some sort of information to this effect at that site.  However, part of what is so, forgive me, powerful about the Chicxulub Impact theory is that its not just a site that supports the bollide kill theory, but many.  There are several possible scenarios that could produce what Tobin et al find.  If you had the a site that contained dead zones found in the Gulf after the oil disaster (and somewhat before) without any other locales, you might draw the conclusions that the Gulf was experiencing a benthic extinction.  More sites to support the claim ought to be found for this to be well supported.

More later.  Including paper link.

What's Left After Peeling 25 lbs

Well, or what gets thrown away after 25 lbs is peeled.  But of what?  ;)