What Lies Beneath? Monster Caverns Ate Floods on Mars?

An international research team led by the Planetary Science Institute has found evidence that indicates that approximately 2 billion years ago enormous volumes of catastrophic floods discharges may have been captured by extensive systems of caverns on Mars, said PSI Research Scientist, J. Alexis Palmero Rodriguez.

Rodriguez and the research team came to this conclusion after studying the terminal regions of the Hebrus Valles, an outflow channel that extends approximately 250 kilometers downstream from two zones of surface collapse.

The Martian outflow channels comprise some of the largest known channels in the solar system. Although it has been proposed their discharge history may have once led to the formation of oceans, the ultimate fate and nature of the fluid discharges has remained a mystery for more than 40 years, and their excavation has been attributed to surface erosion by glaciers, debris flows, catastrophic floodwaters, and perhaps even lava flows, Rodriguez said.

The PSI-led team's work documents the geomorphology of Hebrus Valles, a Martian terrain that is unique in that it preserves pristine landforms located at the terminal reaches of a Martian outflow channel. These generally appear highly resurfaced, or buried, at other locations in the planet. Rodriguez and his co-authors propose in an article titled "Infiltration of Martian overflow channel floodwaters into lowland cavernous systems" published in Geophysical Research Letters that large volumes of catastrophic floodwaters, which participated in the excavation of Hebrus Valles, may have encountered their ultimate fate in vast cavernous systems.

They hypothesize that evacuated subsurface space during mud volcanism was an important process in cavern development. Mud volcanism can expel vast volumes of subsurface volatiles and sediments to the surface. But because evacuation of subsurface materials generally occurs within unconsolidated sediments resulting caverns are transient and mechanically highly unstable.

However, the investigated Martian caverns appear to have developed within permafrost, which at -65 degrees Celsius (-85 degree Fahrenheit) - a typical mean annual surface temperature for the investigated latitudes - has a mechanical strength similar to that of limestone. Limestone rocks host most of the terrestrial cavern systems.

Sounds almost Baxter-esque.

Nyasasaurus: Earliest Dinosaur From the Anisian?

Researchers have discovered what may be the earliest dinosaur, a creature the size of a Labrador retriever, but with a five foot-long tail, that walked the Earth about 10 million years before more familiar dinosaurs like the small, swift-footed Eoraptor and Herrerasaurus.

The findings mean that the dinosaur lineage appeared 10 million to 15 million years earlier than fossils previously showed, originating in the Middle Triassic rather than in the Late Triassic period.

"If the newly named Nyasasaurus parringtoni is not the earliest dinosaur, then it is the closest relative found so far," according to Sterling Nesbitt, a University of Washington postdoctoral researcher in biology and lead author of a paper published online Dec. 5 in Biology Letters, a journal of the United Kingdom's Royal Society.

"For 150 years, people have been suggesting that there should be Middle Triassic dinosaurs, but all the evidence is ambiguous," he said. "Some scientists used fossilized footprints, but we now know that other animals from that time have a very similar foot. Other scientists pointed to a single dinosaur-like characteristic in a single bone, but that can be misleading because some characteristics evolved in a number of reptile groups and are not a result of a shared ancestry."

The researchers had one humerus – or upper arm bone – and six vertebrae to work with. They determined that the animal likely stood upright, measured 7 to 10 feet in length (2 to 3 meters), was as tall as 3 feet at the hip (1 meter) and may have weighed between 45 and 135 pounds (20 to 60 kilograms).

The fossilized bones were collected in the 1930s from Tanzania, but it may not be correct to say dinosaurs originated in that country. When Nyasasaurus parringtoni lived, the world's continents were joined in the landmass called Pangaea. Tanzania would have been part of Southern Pangaea that included Africa, South America, Antarctica and Australia.

"The new findings place the early evolution of dinosaurs and dinosaur-like reptiles firmly in the southern continents," said co-author Paul Barrett at the Natural History Museum, London.

The bones of the new animal reveal a number of characteristics common to early dinosaurs and their close relatives. For example, the bone tissues in the upper arm bone appear as if they are woven haphazardly and not laid down in an organized way. This indicates rapid growth, a common feature of dinosaurs and their close relatives.

"We can tell from the bone tissues that Nyasasaurus had a lot of bone cells and blood vessels," said co-author Sarah Werning at the University of California, Berkeley, who did the bone analysis. "In living animals, we only see this many bone cells and blood vessels in animals that grow quickly, like some mammals or birds."

"The bone tissue of Nyasasaurus is exactly what we would expect for an animal at this position on the dinosaur family tree," she added. "It's a very good example of a transitional fossil; the bone tissue shows that Nyasasaurus grew about as fast as other primitive dinosaurs, but not as fast as later ones."

Another example is the upper arm bone's distinctively enlarged crest, needed to anchor the upper arm muscles. The feature, known as an elongated deltopectoral crest, is also common to all early dinosaurs.

"Nyasasaurus and its age have important implications regardless of whether this taxon is a dinosaur or the closest relatives of dinosaurs," Nesbitt said. "It establishes that dinosaurs likely evolved earlier than previously expected and refutes the idea that dinosaur diversity burst onto the scene in the Late Triassic, a burst of diversification unseen in any other groups at that time."

It now appears that dinosaurs were just part of a large diversification of archosaurs. Archosaurs were among the dominant land animals during the Triassic period 250 million to 200 million years ago and include dinosaurs, crocodiles and their kin.

"Dinosaurs are just part of this archosaur diversification, an explosion of new forms soon after the Permian extinction," Nesbitt said.

Permian Extinction Was Really Two Different Extinctions?

Two pulses of extinction during the Permian–Triassic crisis

Authors:

1. Haijun Song (a,*)
2. Paul B.Wignall (b)
3. Jinnan Tong (a)
4. Hongfu Yin (a)

Affiliations:

a. State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences,Wuhan 430074, China,

b. School of Earth and Environment, University of Leeds, Leeds LS2 9JT, UK.

*. e-mail: haijun.song@yahoo.com.cn.

Abstract:

The Permian–Triassic mass extinction is the most severe biotic crisis identified in Earth history. Over 90% of marine species were eliminated1, 2, causing the destruction of the marine ecosystem structure3. This biotic crisis is generally interpreted as a single extinction event around 252.3 million years ago2, 4, 5, 6, and has been variously attributed to the eruption of the Siberian Traps or possibly a bolide impact7, 8, 9, 10. Here we demonstrate that the marine extinction consisted of two pulses, separated by a 180,000-year recovery phase. We evaluated the range of 537 species representing 17 marine groups in seven Chinese sections from a 450,000-year interval spanning the Permian–Triassic boundary. The first stage of extinction occurred during the latest Permian, and was marked by the extinction of 57% of species, namely all plankton and some benthic groups, including algae, rugose corals, and fusulinids. The second phase occurred in the earliest Triassic, and resulted in the extinction of 71% of the remaining species. This second extinction phase fundamentally altered the marine ecosystem structure that had existed for the previous 200 million years. Because the two pulses showed different extinction selectivity, we conclude that they may have had different environmental causes.

Interesting. A few comments here.  

 Woo for looking at the selectivity of the extinctions!  I'd almost think that I had an impact (ahem, pun.  get it!) with my post from way back when entitled 'Stop Dreaming.'

Its been acknowledged for some time that the Permian Extinction had multiple pulses in the event when things died. Once upon a time, the Guadelupean Extinction was thought to be part of the general end Permian Extinction. 

I'm a bit concerned about their accuracy for timing of the two events: 400k years is really, really close when considering that this happened 250 odd million years ago. Being that accurate seems...difficult at best.

Mass extinctions are complex things.  The kill mechanisms are not simply THE VOLCANO DID IT for the Permian Extinction.  My now old post on the subject neglects a number of other things that have come to light since I wrote it in 2006: RUBISCO temperature limits, halogen releasing salt lakes, UV scorching, etc all had their part...yet the root cause was the Siberian Traps even if the kill mechanisms were varied.

Finally, there is the possibility that the the kitchen sink was the culprit: perhaps a bollide and the traps did the deed or some other event combo.  Douglas Erwin made the suggestion back in the early 1990s.  My bet is more on the previous comment: the root cause was straight forward, but that it enabled multiple kill mechanisms.

Angiosperms' Rise to Dominance in Cretaceous Europe

Rise to dominance of angiosperm pioneers in European Cretaceous environments

Authors:

1. Clément Coiffard (a)
2. Bernard Gomez (b,*)
3. Véronique Daviero-Gomez (b)
4. David L. Dilcher (c,*)

Affiliations:

a. Museum für Naturkunde, Leibniz Institut für Evolutions und Biodiversitätsforschung, Invalidenstrasse 43, D-10115 Berlin, Germany

b. Centre National de la Recherche Scientifique Unité Mixte de Recherche 5276, Laboratoire de Géologie de Lyon–Terre, Planètes, Environnement, Université Lyon 1 (Claude Bernard), F-69622 Villeurbanne Cedex, France

c. Department of Geology, Indiana University, Bloomington, IN 47405-7005

*. To whom correspondence may be addressed. E-mail: dilcher@indiana.edu or bernard.gomez@univ-lyon1.fr.

Abstract:

The majority of environments are dominated by flowering plants today, but it is uncertain how this dominance originated. This increase in angiosperm diversity happened during the Cretaceous period (ca. 145–65 Ma) and led to replacement and often extinction of gymnosperms and ferns. We propose a scenario for the rise to dominance of the angiosperms from the Barremian (ca. 130 Ma) to the Campanian (ca. 84 Ma) based on the European megafossil plant record. These megafossil data demonstrate that angiosperms migrated into new environments in three phases: (i) Barremian (ca. 130–125 Ma) freshwater lake-related wetlands; (ii) Aptian–Albian (ca. 125–100 Ma) understory floodplains (excluding levees and back swamps); and (iii) Cenomanian–Campanian (ca. 100–84 Ma) natural levees, back swamps, and coastal swamps. This scenario allows for the measured evolution of angiosperms in time and space synthesizing changes in the physical environment with concomitant changes in the biological environment. This view of angiosperm radiation in three phases reconciles previous scenarios based on the North American record. The Cretaceous plant record that can be observed in Europe is exceptional in many ways. (i) Angiosperms are well preserved from the Barremian to the Maastrichtian (ca. 65 Ma). (ii) Deposits are well constrained and dated stratigraphically. (iii) They encompass a full range of environments. (iv) European paleobotany provides many detailed studies of Cretaceous floras for analysis. These factors make a robust dataset for the study of angiosperm evolution from the Barremian to the Campanian that can be traced through various ecosystems and related to other plant groups occupying the same niches.

Brown Dwarfs (Dwarves?) May Have Rocky Worlds

Rocky planets are thought to form through the random collision and sticking together of what are initially microscopic particles in the disc of material around a star. These tiny grains, known as cosmic dust, are similar to very fine soot or sand. However, in the outer regions around a brown dwarf -- a star-like object, but one too small to shine brightly like a star -- astronomers expected that grains could not grow because the discs were too sparse, and particles would be moving too fast to stick together after colliding. Also, prevailing theories say that any grains that manage to form should move quickly towards the central brown dwarf, disappearing from the outer parts of the disc where they could be detected.

"We were completely surprised to find millimetre-sized grains in this thin little disc," said Luca Ricci of the California Institute of Technology, USA, who led a team of astronomers based in the United States, Europe and Chile. "Solid grains of that size shouldn't be able to form in the cold outer regions of a disc around a brown dwarf, but it appears that they do. We can't be sure if a whole rocky planet could develop there, or already has, but we're seeing the first steps, so we're going to have to change our assumptions about conditions required for solids to grow," he said.

ALMA's increased resolution compared to previous telescopes also allowed the team to pinpoint carbon monoxide gas around the brown dwarf -- the first time that cold molecular gas has been detected in such a disc. This discovery, and that of the millimetre-size grains, suggest that the disc is much more similar to the ones around young stars than previously expected.

Ricci and his colleagues made their finding using the partially completed ALMA telescope in the high-altitude Chilean desert. ALMA is a growing collection of high precision, dish-shaped antennas that work together as one large telescope to observe the Universe with groundbreaking detail and sensitivity. ALMA "sees" the Universe in millimetre-wavelength light, which is invisible to human eyes. Construction of ALMA is scheduled to finish in 2013, but astronomers began observing with a partial array of ALMA dishes in 2011.

The astronomers pointed ALMA at the young brown dwarf ISO-Oph 102, also known as Rho-Oph 102, in the Rho Ophiuchi star-forming region in the constellation of Ophiuchus (The Serpent Bearer). With about 60 times the mass of Jupiter but only 0.06 times that of the Sun, the brown dwarf has too little mass to ignite the thermonuclear reactions by which ordinary stars shine. However, it emits heat released by its slow gravitational contraction and shines with a reddish colour, albeit much less brightly than a star.

ALMA collected light with wavelengths around a millimetre, emitted by disc material warmed by the brown dwarf. The grains in the disc do not emit much radiation at wavelengths longer than their own size, so a characteristic drop-off in the brightness can be measured at longer wavelengths. ALMA is an ideal instrument for measuring this drop-off and thus for sizing up the grains. The astronomers compared the brightness of the disc at wavelengths of 0.89 mm and 3.2 mm. The drop-off in brightness from 0.89 mm to 3.2 mm was not as steep as expected, showing that at least some of the grains are a millimetre or more in size.

"ALMA is a powerful new tool for solving mysteries of planetary system formation," commented Leonardo Testi from ESO, a member of the research team. "Trying this with previous generation telescopes would have needed almost a month of observing -- impossibly long in practice. But, using just a quarter of ALMA's final complement of antennas, we were able to do it in less than one hour!" he said.

In the near future, the completed ALMA telescope will be powerful enough to make detailed images of the discs around Rho-Oph 102 and other objects. Ricci explained, "We will soon be able to not only detect the presence of small particles in discs, but to map how they are spread across the circumstellar disc and how they interact with the gas that we've also detected in the disc. This will help us better understand how planets come to be."

The Weather We Just Had

And may be about to have, it's all the fault of atmospheric rivers.

CoFounder of IRobot Goes for Aerial Bots Now

Does Venus Have Active Volcanoes?

Incredibly dense, visually opaque and loaded with caustic sulfuric acid, Venus’ atmosphere oppresses a scorched, rocky surface baking in planet-wide 425 ºC (800 ºF) temperatures. Although volcanoes have been mapped on our neighboring planet’s surface, some scientists believe the majority of them have been inactive — at least since the last few hundreds of thousands of years. Now, thanks to NASA’s Pioneer Venus and ESA’s Venus Express orbiters, scientists have nearly 40 years of data on Venus’ atmosphere — and therein lies evidence of much more recent large-scale volcanic activity.

The last six years of observations by Venus Express have shown a marked rise and fall of the levels of sulfur dioxide (SO2) in Venus’ atmosphere, similar to what was seen by NASA’s Pioneer Venus mission from 1978 to 1992.

These spikes in SO2 concentrations could be the result of volcanoes on the planet’s surface, proving that the planet is indeed volcanically active — but then again, they could also be due to variations in Venus’ complex circulation patterns which are governed by its rapid “super-rotating” atmosphere.

“If you see a sulphur dioxide increase in the upper atmosphere, you know that something has brought it up recently, because individual molecules are destroyed there by sunlight after just a couple of days,” said Dr. Emmanuel Marcq of Laboratoire Atmosphères in France, lead author of the paper, “Evidence for Secular Variations of SO2 above Venus’ Clouds Top,” published in the Dec. 2 edition of Nature Geoscience.

“A volcanic eruption could act like a piston to blast sulphur dioxide up to these levels, but peculiarities in the circulation of the planet that we don’t yet fully understand could also mix the gas to reproduce the same result,” added co-author Dr Jean-Loup Bertaux, Principal Investigator for the instrument on Venus Express.

Could Stars Richer in Uranium and Thorium Be Better Harbors for Life?

Scattered around the Milky Way are stars that resemble our own sun—but a new study is finding that any planets orbiting those stars may very well be hotter and more dynamic than Earth.

That's because the interiors of any terrestrial planets in these systems are likely warmer than Earth—up to 25 percent warmer, which would make them more geologically active and more likely to retain enough liquid water to support life, at least in its microbial form.

The preliminary finding comes from geologists and astronomers at Ohio State University who have teamed up to search for alien life in a new way.

They studied eight "solar twins" of our sun—stars that very closely match the sun in size, age, and overall composition—in order to measure the amounts of radioactive elements they contain. Those stars came from a dataset recorded by the High Accuracy Radial Velocity Planet Searcher spectrometer at the European Southern Observatory in Chile.

They searched the solar twins for elements such as thorium and uranium, which are essential to Earth's plate tectonics because they warm our planet's interior. Plate tectonics helps maintain water on the surface of the Earth, so the existence of plate tectonics is sometimes taken as an indicator of a planet's hospitality to life.

Of the eight solar twins they've studied so far, seven appear to contain much more thorium than our sun—which suggests that any planets orbiting those stars probably contain more thorium, too. That, in turn, means that the interior of the planets are probably warmer than ours.

For example, one star in the survey contains 2.5 times more thorium than our sun, said Ohio State doctoral student Cayman Unterborn. According to his measurements, terrestrial planets that formed around that star probably generate 25 percent more internal heat than Earth does, allowing for plate tectonics to persist longer through a planet's history, giving more time for live to arise.

"If it turns out that these planets are warmer than we previously thought, then we can effectively increase the size of the habitable zone around these stars by pushing the habitable zone farther from the host star, and consider more of those planets hospitable to microbial life," said Unterborn, who presented the results at the American Geophysical Union meeting in San Francisco this week.

"At this point, all we can say for sure is that there is some natural variation in the amount of radioactive elements inside stars like ours," he added. "With only nine samples including the sun, we can't say much about the full extent of that variation throughout the galaxy. But from what we know about planet formation, we do know that the planets around those stars probably exhibit the same variation, which has implications for the possibility of life."

His advisor, Wendy Panero, associate professor in the School of Earth Sciences at Ohio State, explained that radioactive elements such as thorium, uranium, and potassium are present within Earth's mantle. These elements heat the planet from the inside, in a way that is completely separate from the heat emanating from Earth's core.

"The core is hot because it started out hot," Panero said. "But the core isn't our only heat source. A comparable contributor is the slow radioactive decay of elements that were here when the Earth formed. Without radioactivity, there wouldn't be enough heat to drive the plate tectonics that maintains surface oceans on Earth."

The relationship between plate tectonics and surface water is complex and not completely understood. Panero called it "one of the great mysteries in the geosciences." But researchers are beginning to suspect that the same forces of heat convection in the mantle that move Earth's crust somehow regulate the amount of water in the oceans, too.

"It seems that if a planet is to retain an ocean over geologic timescales, it needs some kind of crust 'recycling system,' and for us that's mantle convection," Unterborn said.

In particular, microbial life on Earth benefits from subsurface heat. Scores of microbes known as archaea do not rely on the sun for energy, but instead live directly off of heat arising from deep inside the Earth.

On Earth, most of the heat from radioactive decay comes from uranium. Planets rich in thorium, which is more energetic than uranium and has a longer half-life, would "run" hotter and remain hot longer, he said, which gives them more time to develop life.

NEURON's First Flight

X-47B UCAV's First Catapult Launch

China launches a fighter off its carrier...and the US test launches a stealthy UCAV.  huh.

HOLY CRAP! I Wish This Had Come Out When I Was a Kid!

damnit.  Now I need to figure out how to scrape together enough for my son.

Is the Grand Canyon 70 Million Years Old?

An analysis of mineral grains from the bottom of the western Grand Canyon indicates it was largely carved out by about 70 million years ago -- a time when dinosaurs were around and may have even peeked over the rim, says a study led by the University of Colorado Boulder.

The new research pushes back the conventionally accepted date for the formation of the Grand Canyon in Arizona by more than 60 million years, said CU-Boulder Assistant Professor Rebecca Flowers. The team used a dating method that exploits the radioactive decay of uranium and thorium atoms to helium atoms in a phosphate mineral known as apatite, said Flowers, a faculty member in CU-Boulder's geological sciences department.

The helium atoms were locked in the mineral grains as they cooled and moved closer to the surface during the carving of the Grand Canyon, she said. Temperature variations at shallow levels beneath the Earth's surface are influenced by topography, and the thermal history recorded by the apatite grains allowed the team to infer how much time had passed since there was significant natural excavation of the Grand Canyon, Flowers said.

"Our research implies that the Grand Canyon was directly carved to within a few hundred meters of its modern depth by about 70 million years ago," said Flowers. A paper on the subject by Flowers and Professor Kenneth Farley of the California Institute of Technology was published online Nov. 29 in Science magazine.

Flowers said there is significant controversy among scientists over the age and evolution of the Grand Canyon. A variety of data suggest that the Grand Canyon had a complicated history, and the entire modern canyon may not have been carved all at the same time. Different canyon segments may have evolved separately before coalescing into what visitors see today.

In a 2008 study, Flowers and colleagues showed that parts of the eastern section of the Grand Canyon likely developed some 55 million years ago, although the bottom of that ancient canyon was above the height of the current canyon rim at that time before it subsequently eroded to its current depth.

Over a mile deep in places, Arizona's steeply sided Grand Canyon is about 280 miles long and up to 18 miles wide in places. Visited by more than 5 million people annually, the iconic canyon was likely carved in large part by an ancestral waterway of the Colorado River that was flowing in the opposite direction millions of years ago, said Flowers.

"An ancient Grand Canyon has important implications for understanding the evolution of landscapes, topography, hydrology and tectonics in the western U.S. and in mountain belts more generally," said Flowers. The study was funded in part by the National Science Foundation.

Whether helium is retained or lost from the individual apatite crystals is a function of temperatures in the rocks of Earth's crust, she said. When temperatures of the apatite grains are greater than 158 degrees Fahrenheit, no helium is retained in the apatite, while at temperatures below 86 degrees F, all of the helium is retained.

"The main thing this technique allows us to do is detect variations in the thermal structure at shallow levels of the Earth's crust," she said. "Since these variations are in part induced by the topography of the region, we obtained dates that allowed us to constrain the timeframe when the Grand Canyon was incised."

Flowers and Farley took their uranium/thorium/helium dating technique to a more sophisticated level by analyzing the spatial distribution of helium atoms near the margin of individual apatite crystals. "Knowing not just how much helium is present in the grains but also how it is distributed gives us additional information about whether the rocks had a rapid cooling or slow cooling history," said Flowers.

How Evolution Works Isn't Simple

While processes of evolution are largely studied by observation and experiment in the living world, evolutionary tempo and mode – rates and patterns of change, respectively – are mostly revealed by studying the fossil record. Paleontologists measure parts of the hard skeletal fossil remains of once-living organisms that they believe best represent the morphology, or form, of those organisms. They then analyze the variation in these traits through successive layers of rock that were laid down over longs spans of geologic time in order to determine the tempo and mode of species evolution. Punctuated equilibrium postulates that most evolutionary change takes place in relatively short periods of time during the origination of new species, while species themselves mostly undergo stasis, or little change, over longer periods. Several recent studies have indicated that stasis is much more common than gradual directional change in the fossil record. Mosaic evolution, on the other hand, is the tendency for different parts within species to evolve in different ways or at different rates.

The new study is based on data taken from hundreds of sequences of fossil samples previously reported in the scientific literature, but uses model selection methods available only in the last several years. The researchers compared models describing different modes of change, namely stasis, random change, and directional change, to each fossil series and found that different traits generally showed different, conflicting evolutionary modes within the same species. Many kinds of life were represented, including mammals, fish, mollusks, arthropods, and single-celled organisms. This large comparative study validates the ubiquity of mosaic evolution. However, it also raises questions about the evidence for different evolutionary modes, since the great majority of previous studies that quantify stasis, punctuated equilibrium, and gradual or "random" patterns in the fossil record are based on measurements of single traits, not on combined analyses of many traits. Further research will be required to establish the underlying processes driving the patterns of mosaic evolution and fossil species change. Nonetheless, the study is an excellent example of an emerging revolution in scientific inquiry as new techniques are used to breathe new life into old data.

Can White Dwarf and Brown Dwarf Stars Harbor Habitable Worlds?

Astronomers find planets in strange places and wonder if they might support life. One such place would be in orbit around a white or brown dwarf. While neither is a star like the sun, both glow and so could be orbited by planets with the right ingredients for life.

No terrestrial, or Earth-like planets have yet been confirmed orbiting white or brown dwarfs, but there is no reason to assume they don’t exist. However, new research by Rory Barnes of the University of Washington and René Heller of Germany’s Leibniz Institute for Astrophysics Potsdam hints that planets orbiting white or brown dwarfs will prove poor candidates for life.

White dwarfs are the hot cores of dead stars and brown dwarfs are failed stars, objects not massive enough to start nuclear burning as the sun does. In theory, both can be bright enough to theoretically support a habitable zone — that swath of space just right for an orbiting planet’s surface water to be in liquid form, thus giving life a chance.

The inner edge of that just-right zone is where a planet starts to become a runaway greenhouse, such as Venus. That heating phenomenon removes the planet’s surface water and all chance of life — of habitability — is forever lost.

White and brown dwarfs share a common characteristic that sets them apart from normal stars like the sun: They slowly cool and become less luminous over time. And as they cool, their habitable zones gradually shrink inward. Thus, a planet that is found in the center of the habitable zone today must previously have spent time near the zone’s deadly inner edge.

Because of their past, such planet would “face a difficult path to habitability,” Barnes said, even if they’re discovered right in that habitable zone. Call it a sort of cosmic background check, revealing that the worlds probably lost the means to host life long before they became habitable zone residents.

Sounds like great targets for...TERRAFORMING! Woo!

Isreali Stealth UAV/UCAV Project Reported

The Israeli military is developing a large, classified unmanned air vehicle (UAV) with features consistent with stealthy aircraft designs, according to a knowledgable source.

The secret project involves a "fairly large" UAV in development by Israel Aerospace Industries (IAI), the maker of the non-stealthy Heron and Eitan (which is called the Heron TP for export) UAVs, the source says.

Israel has been openly involved with stealth and minimal-detection programmes. Experts familiar with Israeli industry profess little surprise in a low-observable aircraft capability.

"There have been rumours about it, and you see Israeli companies have rolled out an array of products across the spectrum," says a former US government official. "You would expect that stealth is something they'd be interested in, particularly in light of the threats they face."

Israel, a small nation surrounded by largely hostile neighbors, has long placed an emphasis on operating in denied areas with various means. Recent airstrikes thought to involve Israel include a 2007 strike that destroyed a nuclear plant in Syria, and two more recent strikes on targets deep in Sudanese territory. Operations over denied airspace, particularly airspace protected by sophisticated surface-to-air networks, require both stealth and endurance.

"I know that they were working on small and medium-size variants [of stealth aircraft] for some years now," says one industry analyst, who declined to comment on the record. According to the analyst, IAI has been working on stealth technologies since the mid-1990s or earlier.

Diversity of Tetrapod Herbivores From the Late Carboniferous to the Mid Triassic

Reconstructing the diversity of early terrestrial herbivorous tetrapods

Authors:

1. Marianne R. Pearson (a.*)
2. Roger B.J. Benson (a, b)
3. Paul Upchurch (a)
6. Jörg Fröbisch (c)
5. Christian F. Kammerer (c)

Affiliations:

a. University College London, Department of Earth Sciences

b. University of Cambridge, Department of Earth Sciences

c. Museum für Naturkunde, Leibniz-Institut für Evolutions- und Biodiversitätsforschung an der Humboldt-Universität zu Berlin

*.  Author With Whom Communication Is Intended: Email:marianne.pearson@ucl.ac.uk

Abstract:

Terrestrial herbivorous tetrapods first appear in the fossil record during the Late Carboniferous (306.5 Ma). The diversification of herbivores is a key aspect of the transition to the modern trophic structure of terrestrial vertebrate ecosystems, because it allowed tetrapods to exploit terrestrial (i.e. non-aquatic) primary productivity. However, the palaeodiversity dynamics of the earliest terrestrial vertebrate herbivores have received relatively little attention, apart from a few studies that focus on specific clades. A new data set containing 287 species occurrences of herbivorous tetrapods including the major Palaeozoic and Early Triassic clades Anomodontia, Archosauromorpha, Bolosauridae, Captorhinidae, Caseidae, Cynodontia, Dinocephalia, Diadectomorpha, Edaphosauridae, Pareiasauria, Poposauroidea, Procolophonoidea, Rhynchosauria, Silesauridae and Therocephalia is used to analyse palaeodiversity from the Late Carboniferous to the Middle Triassic (~ 306.5 – ~ 236 Ma), taking into account the effects of potential sampling biases by using the number of tetrapod-bearing formations as a proxy. The results support a gradual increase in taxic diversity from the Late Carboniferous to the Wordian, followed by a dip in diversity during the Guadalupian (Middle Permian), and an increase to a peak in the Late Permian at the Wuchiapingian/Changhsingian boundary. Herbivorous tetrapods were strongly affected by the end-Permian mass extinction with both the herbivorous Pareiasauria and Captorhinidae becoming extinct and the observed number of anomodont species decreasing by up to 80%. The drop in observed diversity at the end Permian is dampened slightly because of the radiation of new herbivorous forms during the Early Triassic. A strong biological signal is apparent even after correcting for sampling.

They use the "Land Vertebrate Faunachrons", which I thought were considered flawed.

Sooo...not sure what the accuracy of this is. I Am Not a Triassic (or any really) Paleontologist though.

News Report: Earliest Traissic (Induan) Fossil Forest Found in India

Krishna Chandra Yadav, director, State Forest Research and Training Institute (SFRTI) in Raipur, and colleagues announced the discoveries of the oldest know fossilized trees ever found in India in the November, 26, 2012, issue of the Indian Express.

The fossilized gymnosperms were scattered across a 700 hectares area of the Shankarpur, Bhattidarh, Thadadpahri, and Naginjhiria villages of the Surajpur district on the northern fringe of Tamor Pingla Wildlife Sanctuary.

The 250 million years Triassic fossil trees measured as large as 15 meters in length and eight meters in diameter. Many of the stones (fossil trees) were so large local villagers had used the fossils as building materials for their homes and farm buildings. Previous fossil trees in India have been found that were 50 million years old.

Researchers from Birbal Sahni Institute of Palaeobotany in Lucknow confirmed the discovery.

Um. That tree diameter sounds like a journalistic oops. However, it'd be an exciting site to work because of the fact the Induan is right after the PT Extinction.  A petrified forest of India sounds awesome.

Simulation Claims Mars Would Still be Cold With a Thicker Atmosphere

3D modelling of the early Martian Climate under a denser CO2 atmosphere: Temperatures and CO2 ice clouds

Authors:

1. Francois Forget (a,*)

2. Robin Wordsworth (a)

3. Ehouarn Millour (a)

4. Jean-Baptiste Madeleine (a)

5. Laura Kerber (a)

6. Jeremy Leconte (a)

7. Emmanuel Marcq (b)

8. Robert M. Haberle (c)

Affiliations:

a. LMD, Institut Pierre-Simon Laplace, Universit P. et M. Curie BP99, 75005 Paris , France

b. LATMOS, Institut Pierre-Simon Laplace, 78280 Guyancourt, France

c. NASA Ames Research Center, Space Science Division, MS 245-3, Moffett Field, CA, 94035-1000, USA.

∗ Corresponding author. E-mail: forget@lmd.jussieu.fr

Abstract:

On the basis of geological evidence, it is often stated that the early martian climate was warm enough for liquid water to flow on the surface thanks to the greenhouse effect of a thick atmosphere. We present 3D global climate simulations of the early martian climate performed assuming a faint young sun and a CO2 atmosphere with pressure between 0.1 and 7 bars. The model includes a detailed radiative transfer model using revised CO2 gas collision induced absorption properties, and a parameterisation of the CO2 ice cloud microphysical and radiative properties. A wide range of possible climates is explored by using various values of obliquities, orbital parameters, cloud microphysic parameters, atmospheric dust loading, and surface properties. Unlike on present day Mars, for pressures higher than a fraction of a bar, surface temperatures vary with altitude because of the adiabatic cooling and warming of the atmosphere when it moves vertically. In most simulations, CO2 ice clouds cover a major part of the planet but greenhouse effect does not exceed +15 K. We find that a CO2 atmosphere could not have raised the annual mean temperature above 0 C anywhere on the planet. The collapse of the atmosphere into permanent CO2 ice caps is predicted for pressures higher than 3 bar, or conversely at pressure lower than one bar if the obliquity is low enough. Summertime diurnal mean surface temperatures above 0{\deg}C (a condition which could have allowed rivers to form) are predicted for obliquity larger than 40{\deg} at high latitudes but not in locations where most valley networks are observed. In the absence of other warming mechanisms, our climate model results are thus consistent with a cold early Mars scenario in which non climatic mechanisms must occur to explain the evidence for liquid water. In a companion paper by Wordsworth et al., we simulate the hydrological cycle on such a planet.

No Jovians Means No Heavy Bombardment Period?

Using ESA's Herschel space observatory, astronomers have discovered vast comet belts surrounding two nearby planetary systems known to host only Earth-to-Neptune-mass worlds. The comet reservoirs could have delivered life-giving oceans to the innermost planets.

In a previous Herschel study, scientists found that the dusty belt surrounding nearby star Fomalhaut must be maintained by collisions between comets.

In the new Herschel study, two more nearby planetary systems – GJ 581 and 61 Vir – have been found to host vast amounts of cometary debris.

Herschel detected the signatures of cold dust at 200ºC below freezing, in quantities that mean these systems must have at least 10 times more comets than in our own Solar System's Kuiper Belt.

GJ 581, or Gliese 581, is a low-mass M dwarf star, the most common type of star in the Galaxy. Earlier studies have shown that it hosts at least four planets, including one that resides in the 'Goldilocks Zone' – the distance from the central sun where liquid surface water could exist.

Two planets are confirmed around G-type star 61 Vir, which is just a little less massive than our Sun.

The planets in both systems are known as 'super-Earths', covering a range of masses between 2 and 18 times that of Earth.

Interestingly, however, there is no evidence for giant Jupiter- or Saturn-mass planets in either system.

The gravitational interplay between Jupiter and Saturn in our own Solar System is thought to have been responsible for disrupting a once highly populated Kuiper Belt, sending a deluge of comets towards the inner planets in a cataclysmic event that lasted several million years.

"The new observations are giving us a clue: they're saying that in the Solar System we have giant planets and a relatively sparse Kuiper Belt, but systems with only low-mass planets often have much denser Kuiper belts," says Dr Mark Wyatt from the University of Cambridge, lead author of the paper focusing on the debris disc around 61 Vir.

"We think that may be because the absence of a Jupiter in the low-mass planet systems allows them to avoid a dramatic heavy bombardment event, and instead experience a gradual rain of comets over billions of years."

Which might mean no 'life.'