Welcome to the Saturday Science Edition of Overnight News Digest.
Astronomy
Curiosity Analyzing Sample Of Martian Mountain The second bite of a martian mountain taken by NASA's Curiosity Mars rover hints at long-ago effects of water that was more acidic than any evidenced in the rover's first taste of Mount Sharp, a layered rock record of ancient martian environments. The rover used a new, low-percussion-level drilling technique to collect sample powder last week from a rock target called "Mojave 2." [...] A preliminary check of the minerals in the Mojave 2 sample comes from analyzing it with the Chemistry and Mineralogy (CheMin) instrument inside Curiosity. The still-partial analysis shows a significant amount of jarosite, an oxidized mineral containing iron and sulfur that forms in acidic environments. "Our initial assessment of the newest sample indicates that it has much more jarosite than Confidence Hills," said David Vaniman of the Planetary Science Institute in Tucson, Arizona. The minerals in Confidence Hills indicate less acidic conditions of formation. [...] The rover's drill has six percussion-level settings ranging nearly 20-fold in energy, from tapping gently to banging vigorously, all at 30 times per second. The drill monitors how rapidly or slowly it is penetrating the rock and autonomously adjusts its percussion level. At the four targets before Mojave 2, including three before Curiosity reached Mount Sharp, sample-collection drilling began at level four and used an algorithm that tended to remain at that level. The new algorithm starts at level one, then shifts to a higher level only if drilling progress is too slow. The Mojave 2 rock is so soft, the drill reached its full depth of about 2.6 inches (6.5 centimeters) in 10 minutes using just levels one and two of percussion energy. astronomy
O---O---O
Yellowballs: A New View Of Star Formation A blue squiggle, green peas, and now yellowballs. Citizen scientists at Zooniverse take on the deceptively simple task of classifying objects in deep-space images. But they do far more than they’re asked, and they discover some curious things along the way. Over the past few years, the general public has not only classified more than 900,000 galaxies by type and found more than 600,000 star-blown bubbles, they’ve also discovered objects like the famous Hanny’s Voorwerp and so-called green-pea galaxies. Now another oddball discovery is providing a new view of star formation. Visitors to the Milky Way Project see a gallery of Spitzer Space Telescope infrared images of our galaxy. The stunning views are a nice perk to their job: finding bubbles in the Milky Way. New massive stars blow these giant bubbles, their stellar winds carving out hot cavities ringed by cooler organic molecules that glow green in the false-color images. Before they emerge from their dusty cocoons, though, the not-yet-stars must grow from cool clumps of dense gas into ready-to-burn protostars, heating up their surroundings in the process. A citizen-science discovery has shown scientists a new way of seeing this hidden phase of star formation. [...] A professional astronomer checking in on the [Zooniverse] forum tagged the object with the name #yellowball. Soon that identifier marked another 928 objects. Their yellow color comes from the combined glow of warm dust and organic molecules, whose emissions appear red and green, respectively, in the Spitzer images. Researchers think the yellowballs mark the in-between phase that transitions cool clumps of gas and dust into newly formed stars. skyandtelescope
O---O---O
Dawn Gets Closer Views Of Ceres NASA's Dawn spacecraft, on approach to dwarf planet Ceres, has acquired its latest and closest-yet snapshot of this mysterious world. The image of Ceres, taken on Feb. 4, 2015, from a distance of about 90,000 miles (145,000 kilometers), is available at: http://www.jpl.nasa.gov/spaceimages/details.php?id=pia19174 http://www.jpl.nasa.gov/spaceimages/details.php?id=pia19179 At a resolution of 8.5 miles (14 kilometers) per pixel, the pictures represent the sharpest images to date of Ceres. After the spacecraft arrives and enters into orbit around the dwarf planet, it will study the intriguing world in great detail. Ceres, with a diameter of 590 miles (950 kilometers), is the largest object in the main asteroid belt, located between Mars and Jupiter. Dawn's mission to Vesta and Ceres is managed by the Jet Propulsion Laboratory for NASA's Science Mission Directorate in Washington. Dawn is a project of the directorate's Discovery Program, managed by NASA's Marshall Space Flight Center in Huntsville, Alabama. UCLA is responsible for overall Dawn mission science. Orbital Sciences Corp. of Dulles, Virginia, designed and built the spacecraft. JPL is managed for NASA by the California Institute of Technology in Pasadena. The framing cameras were provided by the Max Planck Institute for Solar System Research, Gottingen, Germany, with significant contributions by the German Aerospace Center (DLR) Institute of Planetary Research, Berlin, and in coordination with the Institute of Computer and Communication Network Engineering, Braunschweig. The visible and infrared mapping spectrometer was provided by the Italian Space Agency and the Italian National Institute for Astrophysics, built by Selex ES, and is managed and operated by the Italian Institute for Space Astrophysics and Planetology, Rome. The gamma ray and neutron detector was built by Los Alamos National Laboratory, New Mexico, and is operated by the Planetary Science Institute, Tucson, Arizona. nasa/jpl
Biology
Sea Slug Has taken Genes From The Algae It Eats, Allowing It To Photosynthesize Like A Plant How a brilliant-green sea slug manages to live for months at a time “feeding” on sunlight, like a plant, is clarified in a recent study published in The Biological Bulletin. The authors present the first direct evidence that the emerald green sea slug’s chromosomes have some genes that come from the algae it eats. These genes help sustain photosynthetic processes inside the slug that provide it with all the food it needs. Importantly, this is one of the only known examples of functional gene transfer from one multicellular species to another, which is the goal of gene therapy to correct genetically based diseases in humans. “Is a sea slug a good [biological model] for a human therapy? Probably not. But figuring out the mechanism of this naturally occurring gene transfer could be extremely instructive for future medical applications,” says study co-author Sidney K. Pierce, an emeritus professor at University of South Florida and at University of Maryland, College Park. Marine Biological Laboratory
O---O---O
Circadian Rhythms Of Crawling And Swimming in the Nudibranch Mollusc Melibe leonina Abstract: Daily rhythms of activity driven by circadian clocks are expressed by many organisms, including molluscs. We initiated this study, with the nudibranch Melibe leonina, with four goals in mind: (1) determine which behaviors are expressed with a daily rhythm; (2) investigate which of these rhythmic behaviors are controlled by a circadian clock; (3) determine if a circadian clock is associated with the eyes or optic ganglia of Melibe, as it is in several other gastropods; and (4) test the hypothesis that Melibe can use extraocular photoreceptors to synchronize its daily rhythms to natural light-dark cycles. To address these goals, we analyzed the behavior of 55 animals exposed to either artificial or natural light-dark cycles, followed by constant darkness. We also repeated this experiment using 10 animals that had their eyes removed. Individuals did not express daily rhythms of feeding, but they swam and crawled more at night. This pattern of locomotion persisted in constant darkness, indicating the presence of a circadian clock. Eyeless animals also expressed a daily rhythm of locomotion, with more locomotion at night. The fact that eyeless animals synchronized their locomotion to the light-dark cycle suggests that they can detect light using extraocular photoreceptors. However, in constant darkness, these rhythms deteriorated, suggesting that the clock neurons that influence locomotion may be located in, or near, the eyes. Thus, locomotion in Melibe appears to be influenced by both ocular and extraocular photoreceptors, although the former appear to have a greater influence on the expression of circadian rhythms. biologicalbulletin
O---O---O
Dirt Mounds Made By Termites In Africa, South America, Asia Could Prevent Spread Of Deserts Termites might not top the list of humanity's favorite insects, but new research suggests that their large dirt mounds are crucial to stopping deserts from spreading into semi-arid ecosystems. The results indicate that termite mounds could make these areas more resilient to climate change. The findings could also inspire a change in how scientists determine the possible effects of climate change on ecosystems. In the parched grasslands and savannas, or drylands, of Africa, South America and Asia, termite mounds store nutrients and moisture and via internal tunnels, allow water to better penetrate the soil. As a result, vegetation flourishes on and near termite mounds in ecosystems that are otherwise vulnerable to desertification. nsf
Chemistry
Europe Mulls Laws To Tackle Microplastic Scourge The European commission has launched a study to determine whether EU regulations are needed to ensure that the use of microplastics in consumer products is phased out as soon as possible to protect marine ecosystems. The announcement comes after five nations – Belgium, the Netherlands, Austria, Sweden and Luxembourg – issued a joint statement in December calling for the EU to ban microplastics and their chemical additives in products such as cosmetics and detergents. The nations defined microplastics as ‘various particles of plastic with a diameter below 5mm’. In March 2011 some 47 world plastic organisations in 29 countries signed a declaration vowing to voluntarily reduce what it called ‘marine litter’ and founded a website to publicise their efforts. But the five nations contend that the voluntarily phase out of microplastics is not working, adding that ‘urgent’ EU regulatory action is necessary. The five nations noted that a commission green paper published in 2013 states that ‘microplastics and the chemical additives they contain, if ingested in large quantities by marine fauna may have a high potential for contaminating the food chain through predator–prey interaction'. The proposed microplastic ban was put up for discussion among environment ministers at a December European council meeting. After discussion, the ministers ‘urged’ the commission and EU member states to study ‘the problem of microplastics in the environment and the need to find adequate solutions to it’. Enrico Brivio, spokesman for European environment, maritime affairs and fisheries commissioner Karmenu Vella, tells Chemistry World that the environment directorate-general, an arm of the commission, has begun a microplastic study in order to gather ‘the necessary information and evidence for developing options’. royalsocietyofchemisty
O---O---O
Two-Dimensional Silicon Makes Its Device Debut Researchers report that they’ve fabricated transistors made of a single layer of silicon atoms connected to three electrodes. These are the first functional devices to use two-dimensional silicon (Nat. Nanotechnol. 2015, DOI: 10.1038/nnano.2014.325). Much like its all-carbon cousin, graphene, silicene promises an exciting array of electronic properties, according to theorists. Scientists believe both 2-D materials could form the basis of smaller, faster transistors—and, in turn, smaller, faster computers. But some argue silicene has the greater potential because the semiconductor industry already relies heavily on silicon. “It’s inertia,” says Deji Akinwande of the University of Texas, Austin. An industry optimized for one material tends to stick with that material, explains Akinwande, who led the effort to build silicene transistors along with Alessandro Molle of the National Research Council of Italy. Still, experimentalists have yet to fully characterize silicene’s electronic properties because the material is unstable. Silicon monolayers are so prone to bonding with oxygen and hydrogen that some researchers are still unconvinced that anyone has studied pure silicene. But the new transistors were produced with a method that could improve silicene’s stability and help further its experimental characterization. The team grew silicene by evaporating silicon atoms onto a smooth silver crystal. The researchers monitored silicene growth in real time using reflection high-energy electron diffraction and scanning tunneling microscopy. Once a 2-D monolayer was complete, they capped the silicene with a thin layer of alumina. Sandwiched between silver and alumina, the silicene remained stable for months, Akinwande says. To complete the transistor, the team transferred the layered structure, alumina side down, to an oxidized silicon substrate that served as a back-gate electrode. Lastly, the team etched the exposed silver layer, generating two distinct pads to form the source and drain electrodes. chemicalandengineeringnews
O---O---O
Inhospitable Climate Fosters Gold Ore Formation The Witwatersrand Basin in South Africa holds the world's largest gold deposits across a 200-km long swathe. Individual ore deposits are spread out in thin layers over areas up to 10 by 10 km and contain more gold than any other gold deposit in the world. Some 40% of the precious metal that has been found up to the present day comes from this area, and hundreds of tons of gold deposits still lie beneath the earth. The manner in which these giant deposits formed is still debated among geologists. Christoph Heinrich, Professor of Mineral Resources at ETH and the University of Zurich, recently published a new explanation in the journal Nature Geoscience, trying to reconcile the contradictions of two previously published theories. The prevailing 'placer gold' theory states that the gold at Witwatersrand was transported and concentrated through mechanical means as metallic particles in river sediment. Such a process has led to the gold-rich river gravels that gave rise to the Californian gold rush. Here, nuggets of placer gold have accumulated locally in river gravels in the foothills of the Sierra Nevada, where primary gold-quarz veins provide a nearby source of the nuggets. But no sufficiently large source exists in the immediate sub-surface of the Witwatersrand Basin. This is one of the main arguments of proponents of the 'hydrothermal hypothesis', according to which gold, chemically dissolved in hot fluid, passed into the sediment layers half a billion years after their deposition. For this theory to work, a 10 km thick blanket of later sediments would be required in order to create the required pressure and temperature. However, the hydrothermal theory is contradicted by geological evidence that the gold concentration must have taken place during the formation of host sediments on the Earth's surface. Rainwater rich in hydrogen sulphide Heinrich believes the concentration of gold took place at the Earth's surface, indeed by flowing river water, but in chemically dissolved form. With such a process, the gold could be easily 'collected' from a much larger catchment area of weathered, slightly gold-bearing rocks. The resource geologist examined the possibility of this middle way, by calculating the chemical solubility of the precious metal in surface water under the prevailing atmospheric and climatic conditions. Experimental data shows that the chemical transport of gold was indeed possible in the early stages of Earth evolution. The prerequisite was that the rainwater had to be at least occasionally very rich in hydrogen sulphide. Hydrogen sulphide binds itself in the weathered soil with widely distributed traces of gold to form aqueous gold sulphide complexes, which significantly increases the solubility of the gold. However, hydrogen sulphide in the atmosphere and sulphurous gold complexes in river water are stable only in the absence of free oxygen. "Quite inhospitable environmental conditions must have dominated, which was possible only three billion years ago during the Archean eon," says Heinrich. "It required an oxygen-free atmosphere that was temporarily very rich in hydrogen sulphide -- the smell of rotten eggs." In today's atmosphere, oxygen oxidises all hydrogen sulphide, thus destroying gold's sulphur complex in a short time, which is why gold is practically insoluble in today's river water. sciencedaily
Earth Science
Seafloor Volcano Pulses May Alter Climate Vast ranges of volcanoes hidden under the oceans are presumed by scientists to be the gentle giants of the planet, oozing lava at slow, steady rates along mid-ocean ridges. But a new study shows that they flare up on strikingly regular cycles, ranging from two weeks to 100,000 years—and, that they erupt almost exclusively during the first six months of each year. The pulses—apparently tied to short- and long-term changes in earth’s orbit, and to sea levels--may help trigger natural climate swings. Scientists have already speculated that volcanic cycles on land emitting large amounts of carbon dioxide might influence climate; but up to now there was no evidence from submarine volcanoes. The findings suggest that models of earth’s natural climate dynamics, and by extension human-influenced climate change, may have to be adjusted. The study appears this week in the journal Geophysical Research Letters. “People have ignored seafloor volcanoes on the idea that their influence is small—but that’s because they are assumed to be in a steady state, which they’re not,” said the study’s author, marine geophysicist Maya Tolstoy of Columbia University’s Lamont-Doherty Earth Observatory. “They respond to both very large forces, and to very small ones, and that tells us that we need to look at them much more closely.” A related study by a separate team this week in the journal Science bolsters Tolstoy’s case by showing similar long-term patterns of submarine volcanism in an Antarctic region Tolstoy did not study. Volcanically active mid-ocean ridges crisscross earth’s seafloors like stitching on a baseball, stretching some 37,000 miles. They are the growing edges of giant tectonic plates; as lavas push out, they form new areas of seafloor, which comprise some 80 percent of the planet’s crust. Conventional wisdom holds that they erupt at a fairly constant rate--but Tolstoy finds that the ridges are actually now in a languid phase. Even at that, they produce maybe eight times more lava annually than land volcanoes. Due to the chemistry of their magmas, the carbon dioxide they are thought to emit is currently about the same as, or perhaps a little less than, from land volcanoes—about 88 million metric tons a year. But were the undersea chains to stir even a little bit more, their CO2 output would shoot up, says Tolstoy. enn
O---O---O
Fossil Divestments Trend Is Killing Coal. Small Norway has the biggest pension fund of all nations. GPFG (The Norwegian Government Pension Fund Global) has $850 billion of funds from the country's fossil fuel wealth, but that does not prevent present-day Norway from being as green as they can. The news this week is that they are divesting their resources from all companies that could be affected by environmental damage regulations in the near future. Global warming may slow after all, although it will take a century! As the Paris Conference on Climate Change approaches, this could mean many investors withdraw funds from the 114 companies involved here. The political element is also effective, of course, but money rules in most cases, so fossils can expect to be left in the ground. Most of the companies are coal mines, tar-sand excavators, cement companies, and electricity generators (with coal fired power stations) Deforestation and environmental disturbance links also caused the demise of coal mines in India, Indonesia and the US. To compound the effects of this giant withdrawal, Chinese demand for coal seems to have peaked and investment advisors have already declared they would encourage an end to the use of coal for electricity generation and investment in it (eg. Axa Investment and Goldman Sachs.) In 2012, the GPFG sold all of its 23 oil palm producer holdings. None had long-term business models in terms of sustainability while Malaysian and Indonesian rainforest degradation were specifically mentioned as being the reason for Golden Agri-Resources and others being dumped. Nuclear weapons and cluster munitions also caused the withdrawal of investment from Lockheed Martin by GPFG and 40 other companies. earthtimes
O---O---O
Al Gore's Spacecraft To Watch Earth And Warn Of Solar Storms Earth’s newest space sentinel, the Deep Space Climate Observatory, is scheduled to launch Sunday to provide a 24-hour view of the Earth’s face and 20- to 30-minute warnings of threatening solar geomagnetic storms before they reach Earth. “These geomagnetic storms can be very dangerous to critical infrastructure on Earth-power grids, aviation communications systems, satellites in orbit,” said Tom Berger of NOAA’s Space Weather Prediction Center. The $340 million National Oceanic and Atmospheric Administration spacecraft will observe both the sun and Earth from a stable point in space roughly one million miles (1.6 million kilometers) away from our planet. The craft is set for a February 8 launch at 6:10 p.m. EST from Cape Canaveral in Florida. “The spacecraft will sit like a lighthouse off the shore, watching for solar storms before they strike our planet,” says solar physicist Thomas Bogdan, head of the University Corporation for Atmospheric Research in Boulder, Colorado. nationalgeographic
Physics
Researchers Use Transmission Electron Microscope As A Thermometer At Nanoscale A team of researchers with the University of California has found a way to use a transmission electron microscope (TEM) as a thermometer for measuring heat in micro-electric devices. In their paper published in the journal Science, the team describes how they discovered using a TEM on a tiny piece of metal could reveal its density change as electrons passed through. Christian Colliex with the L'Université de Paris, offers a Perspective piece on the work by the team in the same journal edition. As microelectronics have grown smaller, it has become more difficult to take their temperature, a necessary part of transistor design—traditional methods such as contact thermometers or radiative measurements become les viable as they tend to add heat or offer poor resolution. That means that scientists have had to look for other ways to get the job done. In this new effort, the researchers went back to one of the original designs, the old-school mercury thermometer, for inspiration. Such old time thermometers were able to note temperature differences because the density of the mercury changed predictably as the temperature changed. The density of other metals change due to temperature differences as well, and that was the approach the team used to measure temperature changes in a very small metal wire. When electricity is sent through a wire, it causes a density change in the wire due to charge vibrations, which can be seen using a TEM at nanometer scale. The researchers sent electricity through a tiny aluminum wire while simultaneously scanning it with a TEM—as the electrons passed through the wire, energy was transferred to the wire in the form of charge oscillations causing a density change—the amount varied by the type of metal used, the team noted. To calculate the temperature of the wire, the researchers simply compared its density with an identical wire sitting at room temperature. The team has dubbed their technique plasmon energy expansion thermometry (PEET). The team claims that their technique could very easily be used in measuring temperatures in actual microelectronic devices and that it could be done using general electron microscopy as well. All it would take, they suggest is the introduction of tiny aluminum nanoparticle samples just next to those metals they are trying to measure. phys.org
O---O---O
Turing Also Present At The Nanoscale In the world of single atoms and molecules governed by chaotic fluctuations, is the spontaneous formation of Turing patterns possible - the same ones that are responsible for the irregular yet periodic shapes of the stripes on zebras' bodies? A Polish-Danish team of physicists has for the first time demonstrated that such a process can not only occur, but can also be used for potentially very interesting applications. Everyone is familiar with a zebra's stripes, but not everyone knows that these are the manifestations of chemical reactions taking place according to a process first described by the famous British mathematician Alan Turing, the creator of the basics of today's computer science. Turing patterns, most commonly displayed in chemistry as periodic changes in the concentration of chemical substances, have hitherto only been observed in dimensions of microns or larger. It seemed that on a smaller scale - at the nanoscale, where random fluctuations rule the movement of single atoms and molecules - these patterns do not have the right to form spontaneously. "So far, no-one has even studied the possibility of the formation of Turing patterns by single atoms or molecules. However, our results show that Turing nanostructures may exist. And since this is the case, we will be able to find very specific applications for them in nanotechnology and materials science," says Dr. Bogdan Nowakowski from the Institute of Physical Chemistry of the Polish Academy of Sciences (IPC PAS) in Warsaw, one of the physicists in the Polish-Danish team that has recently conducted computer simulations and theoretical analyses on Turing nanostructures. Turing patterns occur in dynamic systems far from a state of equilibrium. Under the appropriate conditions there may then be a feedback mechanism: chemical reactions taking place may influence the concentration of their own components, which in turn may change the course of the reaction itself. The process leads to the formation of periodic, but not necessarily monotonously regular patterns. In nature, these patterns play an important role, particularly in the formation of young organisms (morphogenesis). For example, in the initial phases of the development of vertebrate embryos, this is how periodic segments, somites, are formed in the dorsal mesoderm, which are later converted into, among others, vertebrae, components of the spine. phys.org
O---O---O
Photons Simulate Time Travel In The Lab Physicists in Australia claim to have simulated time travel using fairly standard optical equipment on a lab bench. They say they have prepared photons that behave as if they are travelling along short cuts in space–time known as "closed time-like curves", and add that their work might help in the long-sought-after unification of quantum mechanics and gravity. Others, however, argue that the research does little or nothing to establish whether time travel is possible in nature. Although everyday experience suggests the impossibility of travelling backwards or forwards in time, Einstein's general theory of relativity does not rule it out. The theory allows for loops in space–time called closed time-like curves that could be created by very powerful sources of gravity such as black holes. These structures would bring an object back to a place and a time that it had already passed through, typically via a short cut between the two separated regions of space–time known as a wormhole. [...] The quantum-mechanical equivalent of the grandfather paradox involves a subatomic particle that has two states – one and zero – corresponding to "alive" and "dead". The paradox emerges if the particle started out in state one, travelled backwards in time, met a younger version of itself and then flipped the value of its earlier self to zero. But in 1991 David Deutsch of Oxford University showed that the probabilistic nature of quantum mechanics comes to the rescue. Deutsch found that there would always be a state that a quantum particle could assume that would make the particle's trip back in time a safe one. For example, if the particle were to start out in an equal mixture of one and zero, when flipped it would remain in that state – a 50:50 mixture of one and zero. [...] In the latest work, Martin Ringbauer and colleagues at the University of Queensland in Brisbane set out to reproduce Deutsch's model in the laboratory. But given the absence of any real closed time-like curves in the vicinity of their lab, they were not able to directly study the interaction between younger and older versions of the same quantum particle. Instead, they used two separate particles. The idea is that the "younger" particle remains in normal space–time, while the "older" one disappears down a simulated wormhole, reappears in the "past" and then interacts with its junior partner. physicsworld