Welcome to the Saturday Science Edition of Overnight News Digest
Overnight News Digest is a regular daily feature which provides noteworthy news items and commentary from around the world. The editorial staff includes side pocket, maggiejean, wader, Doctor RJ, rfall, and JML9999.
Neon Vincent is our editor-in-chief.
Special thanks go to Magnifico for starting this venerable series.
Astronomy
NASA's Hubble Finds Giant Halo Around The Andromeda Galaxy
Scientists using NASA’s Hubble Space Telescope have discovered that the immense halo of gas enveloping the Andromeda Galaxy (M31), our nearest massive galactic neighbor, is about six times larger and 1,000 times more massive than previously measured. The dark, nearly invisible halo stretches about a million light-years from its host galaxy, halfway to our own Milky Way Galaxy. This finding promises to tell astronomers more about the evolution and structure of majestic giant spirals, one of the most common types of galaxies in the universe. “Halos are the gaseous atmospheres of galaxies. The properties of these gaseous halos control the rate at which stars form in galaxies according to models of galaxy formation,” explained Nicolas Lehner, lead investigator from the University of Notre Dame. The gargantuan halo is estimated to contain half the mass of the stars in the Andromeda Galaxy itself, in the form of a hot, diffuse gas. If it could be viewed with the naked eye, the halo would be 100 times the diameter of the Full Moon in the sky. This is equivalent to the patch of sky covered by two basketballs held at arm’s length. The Andromeda Galaxy lies 2.5 million light-years away and looks like a faint spindle, about six times the diameter of the Full Moon. It is considered a near-twin to the Milky Way Galaxy. Because the gas in Andromeda’s halo is dark, the team looked at bright background objects through the gas and observed how the light changed. This is a bit like looking at a glowing light at the bottom of a pool at night. The ideal background “lights” for such a study are quasars, which are very distant bright cores of active galaxies powered by black holes. The team used 18 quasars residing far behind Andromeda to probe how material is distributed well beyond the visible disk of the galaxy. astronomy.com
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Explosion of US Military Satellite May Endanger Spacecraft After All
The February explosion of an American military satellite may cause some problems for orbiting spacecraft after all, a new study reports. The U.S. Air Force's 20-year-old Defense Meteorological Satellite Program Flight 13 (DMSP-F13) craft blew apart on Feb. 3 after experiencing a power-system faillure. Analyses by the European Space Agency and other organizations found that the cloud of space junk generated by the explosion shouldn't pose much of a threat to their missions, but the new research suggests that not all spacecraft are in the clear. Study leader Francesca Letizia, a graduate student at the University of Southampton in England, and her team spotted 100 new chunks of debris produced by DMSP-F13's violent end. This number suggests that the explosion also created more than 50,000 pieces smaller than 1 millimeter in diameter, the scientists said. "Even though many of these objects will be no bigger than the ball in a ballpoint pen, they can disable a spacecraft in a collision because of their enormous speed," co-author Hugh Lewis, also of the University of Southampton, said in a statement. The team mapped out the spread of DMSP-F13's cloud using new modeling techniques that treated the pieces of debris as a fluid. "Treating the fragment band as a fluid allows us to analyze the motion of a large number of fragments very quickly, and much faster than [using] conventional methods," said co-author Camilla Colombo, who's based at Southampton as well. space.com
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Mysterious X-rays Spotted In Galactic Center
Our galaxy’s center is a crowded place. Neighboring stars are, on average, separated by only 1,000 times the Earth-Sun distance — compare that with the distance between the Sun and its nearest stellar neighbor, Proxima Centauri, which is more like 266,000 times the Earth-Sun distance. In the Milky Way’s center, alien night skies might have a million stars brighter than Sirius. To that sardine-packed mix, add supernova remnants, pulsar winds, and hot filaments of gas. But there’s more than meets the eye in this crowded locale. Kerstin Perez (Columbia University and Haverford College) and colleagues report in the April 30th Nature a new set of observations from NASA’s NuSTAR X-ray telescope that brings that point home. The astronomers found unexpected, high-energy X-rays within the central 10 light-years or so of the center, and they don’t know what’s producing them. The team had NuSTAR zero in on the central 40 light-years of our galaxy for three days’ worth of exposure time over a period of four months. The image the telescope beamed back shows a blotch of high-energy emission (between 20,000 and 40,000 electron volts) concentrated on the galaxy’s center and extended along the galactic plane. In and of themselves, X-rays from the galactic center aren’t unusual. But the X-rays NuSTAR detects don’t seem to be associated with structures already known to exist. For example, a supernova remnant named Sgr A East emits low-energy X-rays but not high-energy X-rays. The high-energy blotch doesn’t correlate with structures seen in radio images either, such as the dust and gas clouds of Sgr A West that are falling toward the supermassive black hole. Instead, Perez and her colleagues propose that thousands of stellar corpses could be responsible for the high-energy X-rays: massive (and still-growing) white dwarfs, spun-up pulsars, or black holes or neutrons stars feeding on low-mass companion stars. skyandtelescope
Biology
These Gigantic Whales Have Nerves Like Bungee Cords
Nerves aren't known for being stretchy. In fact, "nerve stretch injury" is a common form of trauma in humans. But researchers reporting in the Cell Press journal Current Biology on May 4 have discovered that nerves in the mouths and tongues of rorqual whales can more than double their length with no trouble at all. "These large nerves actually stretch and recoil like bungee cords," says A. Wayne Vogl of the University of British Columbia. "This is unlike other nerves in vertebrates, where the nerve is of a more fixed length that has enough slack in it to accommodate changes in position of the structures the nerves are supplying." Those stretchy nerves support the animals' unique and extreme lunge feeding strategy, which helps to support the whales' gigantic bodies. Rorqual whales represent the largest group among baleen whales, weighing in at an impressive 40 to 80 tons. To eat, the whales open their mouths and lunge while their tongues invert and their mouths fill like giant water balloons full of floating prey. Those prey are concentrated by slowly expelling the water through baleen plates. The volume of water brought in with a single gulp can exceed the volume of the whale itself. "Rorqual whales attained large body size with the evolution of a bulk filter feeding mechanism based on engulfing huge volumes of prey-laden water," Vogl says. "This required major changes in anatomy of the tongue and ventral blubber to allow large deformation, and now we recognize that this also required major modifications in the structure of nerves in these tissues so they could withstand the tissue deformation." biologynews
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Ecologist Warns Of Bamboo Fueling Spread Of Hantavirus
Washington State University researchers say the popularity of bamboo landscaping could increase the spread of hantavirus, with the plant's prolific seed production creating a population boom among seed-eating deer mice that carry the disease. [...] Bamboo plants are growing in popularity, judging by the increased number of species listed by the American Bamboo Society. Some grow in relatively self-contained clumps, while other so-called "running bamboos" can spread rapidly by underground stems called rhizomes, making them difficult to contain. They have extremely intermittent flowering cycles but when they flower, or mast, they produce huge amounts of seed over as many as 18 months. During that time, deer mice can undergo several reproductive cycles. When the seed is gone, they will go looking for new food sources in and around human homes and other dwellings. More than one in 10 deer mice carry hantavirus, which is spread through contact with their urine, droppings or contaminated dust. People who catch the disease typically have a few days of flu-like symptoms followed by respiratory and pulmonary complications. Roughly one in three cases is fatal, according to the state Department of Health. [...] Subsequent reproduction trials and population modeling suggested the mice could have population booms similar to those seen in Asian and South American rodents during bamboo masting events. "We contend that a substantial risk of a similar sequence could arise in North America due to the rapid proliferation and expansion of non-native running bamboos within the range of P. maniculatus," [Richard Mack, an ecologist in WSU's School of Biological Sciences] wrote with co-authors Richard Gomulkiewicz, WSU professor, and Melissa Smith, former Mack doctoral student now at the U.S. Department of Agriculture-ARS Invasive Plant Research Laboratory in Fort Lauderdale, Florida. sciencedaily
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Bottlenose Dolphins Form Highly Complex Networks Of Friends
In a 6.5 year study, marine biologists led by Dr Elizabeth Murdoch Titcomb from the Harbor Branch Oceanographic Institute at Florida Atlantic University took a closer look at the interactions between bottlenose dolphins (Tursiops truncatus) in the Indian River Lagoon, Florida, and discovered how the dolphins mingle and with whom they spend their time. Through intensive photo-identification surveys, Dr Titcomb and co-authors were able to learn about the association patterns as well as movement behavior and habitat preferences of 185 individual dolphins. The scientists found that the Indian River Lagoon (IRL) population was highly differentiated and organized into six distinct social communities that tended to occupy discrete core areas along the north-south axis of the lagoon system. They also found that individual dolphins exhibited both preference and avoidance behavior – so just like humans, they have dolphins they like and associate with and ones they avoid.
“One of the more unique aspects of our study was the discovery that the physical dimensions of the habitat, the long, narrow lagoon system itself, influenced the spatial and temporal dynamics of dolphin association patterns,” said Dr Titcomb, lead author on the paper in the journal Marine Mammal Science. “For example, communities that occupy the narrowest stretches of IRL have the most compact social networks, similar to humans who live in small towns and have fewer people with whom to interact.”
sci-news.com
Chemistry
Scientists Call For Ban On Fluorinated Chemicals
More than 200 scientists are urging consumers to avoid products such as raincoats and non-stick frying pans, which contain a class of fluorinated chemicals they say are dangerous to health and the environment. They are also calling on governments to restrict these chemicals’ use, and industry to find safer alternatives. First marketed 60 years ago, poly- and perfluoroalkyl substances (PFASs) have found uses as surfactants, oil- and water-repellent coatings in a range of products including clothing, cosmetics, food packaging and furnishings. But research suggests that the long-chain PFASs are highly persistent, bioaccumulative and toxic, and many countries are now phasing them out. Controversy has also emerged regarding the safety of the most common alternatives, the short-chain PFASs. The Green Science Policy Institute’s ‘Madrid statement’ on fluorinated chemicals is written by 14 experts who document the ‘scientific consensus’ on the persistence and potential for harm of PFASs, and question the use of all PFASs, including short-chain alternatives. Originally unveiled last year, it has now been signed by 206 scientists and professionals. The statement also suggests how scientists, governments, manufacturers, purchasers and consumers can limit the production and use of PFASs. It wants scientists, for example, to compile an inventory of PFASs including precursors and degradation products; and calls on governments to enact legislation requiring only essential uses of PFASs, and forcing manufacturers to conduct more extensive toxicological testing. Retailers and consumers should also stop using PFASs where they are not essential, it says – for example in products that are stain-resistant, waterproof, or non-stick. On the other side of the debate, DuPont spokesperson Janet Smith argues that chemical companies have been working for more than a decade, with oversight from regulators, to introduce safe alternatives to long-chain perfluorinated compounds such as perfluorooctanoic acid (PFOA). ‘As a result of industry efforts, data indicate that levels of PFOA and related chemicals have dropped over the last several years, both in people’s blood and in the environment,’ she tells Chemistry World. ‘The US EPA has stated that these efforts have yielded significant human health and environmental benefits.’ chemistryworld
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X-Rays Reveal How Chocolate Turns White
That white discoloration that sometimes forms on old chocolate turns the stomachs of chocolate lovers everywhere. For years, researchers have known that the harmless change, known as a fat bloom, is caused by liquid fat such as cocoa butter migrating through the chocolate and crystalizing on the candy’s surface. But exactly how that process takes place—and how to prevent it—has remained a mystery. Now, researchers have captured the bloom process in real time, they report online in Applied Materials & Interfaces. After combining the main ingredients of chocolate—cocoa, sugar, milk powder, and cocoa butter—and grounding them into a powder (to speed up the process), the scientists used high-powered x-rays to peer into the sweet’s crystal structure, down to a scale of several nanometers. When they added a few small drops of sunflower oil to the powder samples, they observed the liquid fat moving through pores and tiny spaces in the chocolate very quickly, most likely as a result of capillary action—the movement of a liquid within porous material due to the forces of adhesion, cohesion, and surface tension. After several hours, the oil had also softened the chocolate, leading to increased migration of the fat. The study suggests that reducing the porosity of chocolate when it’s being made could help stem the appearance of the off-putting bloom and improve the overall quality of chocolate. Minimizing the amount of liquid fat in chocolate by storing your hoarded stashes in cool, but not too cold, conditions would also help: Eighteen degrees Celsius, it turns out, is the sweet spot. sciencemag
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Making Sense Of The Chemistry That Led To Life On Earth
It was the actions of Jupiter and Saturn that quite inadvertently created life on Earth — not the gods of the Roman pantheon, but the giant planets, which once orbited much closer to the sun. Driven outward, they let loose a cascade of asteroids, known as the Late Heavy Bombardment, that blasted the surface of the young Earth and created the deep pockmarks still visible on the face of the moon. In the heat of these impacts, carbon from the meteorites reacted with nitrogen in Earth’s atmosphere to form hydrogen cyanide. Though a deadly poison, cyanide is nonetheless the ancient pathway for inert carbon atoms to enter the chemistry of life. By the time the Late Heavy Bombardment had eased, some 3.8 billion years ago, the cyanide had rained down into pools, reacted with metals, evaporated, been baked and irradiated with ultraviolet light, and dissolved by streams flowing down to a freshwater pool. The chemicals formed from the interactions of cyanide combined there in various ways to generate the precursors of lipids, nucleotides and amino acids. These are the three significant components of a living cell — lipids make the walls of a cell’s various compartments; nucleotides store its information; and amino acids assemble into the proteins that control its metabolism. All of this is a hypothesis, proposed by John Sutherland, a chemist at the University of Cambridge in England. But he has tested all the required chemical reactions in a laboratory and developed evidence that they are plausible under the conditions expected of primitive Earth. nyt
Earth Science
Undersea Robots Plan Missions Autonomously
For the last decade, scientists have deployed increasingly capable underwater robots to map and monitor pockets of the ocean to track the health of fisheries, and survey marine habitats and species. In general, such robots are effective at carrying out low-level tasks, specifically assigned to them by human engineers — a tedious and time-consuming process for the engineers. When deploying autonomous underwater vehicles (AUVs), much of an engineer’s time is spent writing scripts, or low-level commands, in order to direct a robot to carry out a mission plan. Now a new programming approach developed by MIT engineers gives robots more “cognitive” capabilities, enabling humans to specify high-level goals, while a robot performs high-level decision-making to figure out how to achieve these goals. For example, an engineer may give a robot a list of goal locations to explore, along with any time constraints, as well as physical directions, such as staying a certain distance above the seafloor. Using the system devised by the MIT team, the robot can then plan out a mission, choosing which locations to explore, in what order, within a given timeframe. If an unforeseen event prevents the robot from completing a task, it can choose to drop that task, or reconfigure the hardware to recover from a failure, on the fly. In March, the team tested the autonomous mission-planning system during a research cruise off the western coast of Australia. Over three weeks, the MIT engineers, along with groups from Woods Hole Oceanographic Institution, the Australian Center for Field Robotics, the University of Rhode Island, and elsewhere, tested several classes of AUVs, and their ability to work cooperatively to map the ocean environment. The MIT researchers tested their system on an autonomous underwater glider, and demonstrated that the robot was able to operate safely among a number of other autonomous vehicles, while receiving higher-level commands. The glider, using the system, was able to adapt its mission plan to avoid getting in the way of other vehicles, while still achieving its most important scientific objectives. If another vehicle was taking longer than expected to explore a particular area, the glider, using the MIT system, would reshuffle its priorities, and choose to stay in its current location longer, in order to avoid potential collisions. enn.com
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Greenhouse Gas Benchmark Reached
For the first time since we began tracking carbon dioxide in the global atmosphere, the monthly global average concentration of this greenhouse gas surpassed 400 parts per million in March 2015, according to NOAA’s latest results. “It was only a matter of time that we would average 400 parts per million globally,” said Pieter Tans, lead scientist of NOAA’s Global Greenhouse Gas Reference Network. “We first reported 400 ppm when all of our Arctic sites reached that value in the spring of 2012. In 2013 the record at NOAA’s Mauna Loa Observatory first crossed the 400 ppm threshold. Reaching 400 parts per million as a global average is a significant milestone. “This marks the fact that humans burning fossil fuels have caused global carbon dioxide concentrations to rise more than 120 parts per million since pre-industrial times,” added Tans. “Half of that rise has occurred since 1980.” The International Energy Agency reported on March 13 that the growth of global emissions from fossil fuel burning stalled in 2014, remaining at the same levels as 2013. Stabilizing the rate of emissions is not enough to avert climate change, however. NOAA data show that the average growth rate of carbon dioxide concentration in the atmosphere from 2012 to 2014 was 2.25 ppm per year, the highest ever recorded over three consecutive years. noaa.gov
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After Oil Spill, Unique Mangrove Forest Faces More Threats
On December 9, 2014, a wrecked tanker released approximately 94,000 gallons (78,271 Imperial gallons) of heavy fuel oil into the Shela River, which runs through the Sundarbans, the sprawling and remote mangrove forest shared between India and Bangladesh in the Bay of Bengal. Now another shipping disaster is unfolding, as a capsized cargo vessel, Jabalenoor, leaks 200 tonnes of potash fertilizer into the Sundarbans’ Bhola River, southeast of the earlier oil spill. A UNESCO World Heritage site, the Sundarbans is home to a variety of wildlife, including an important population of the critically threatened Royal Bengal Tiger and rare Irrawaddy and Gangetic dolphins. In the wake of the oil spill a joint United Nations and Government of Bangladesh Mission published a long-awaited report on the accident. Referring to the incident as a “serious wake up call,” the report urges a number of protective strategies. In particular, the report calls for more stringent management of water routes, noting “an immediate need” to stagger the heavy traffic of commercial vessels, to ban all passage during unsafe conditions, such as at night or fog, and to “prohibit all anchoring in the channel except in an emergency.” nationalgeographic
Physics
A First Step Towards Testing Dark Energy Theories On The Table Top
Scientists from FOM and the VU University Amsterdam have designed an experiment to test a popular candidate theory that could explain the mechanisms behind dark energy. Now, they have reached an important milestone on the long road they have been following for the past four years: a working dark energy force detector. The first few tests with this new device give confidence that the sensitivity required to put the theory to the test can indeed be reached in the setup. Dark energy Physicists know that the expansion of the universe accelerates, but no one knows what the driving force behind this acceleration is. Although the mechanisms of the force remain unknown, physicists have given it a name: dark energy. Calculations show that about 70 percent of the total mass in the universe must be contributed to this mysterious energy, which we can neither see nor measure in any direct way. One of the intriguing facts about dark energy is that it seems to act with enormous force over the vast empty spaces in our universe - pushing space apart, while not having any measurable effect on the scale of planets or even the solar system. This adaptive nature of dark energy has motivated the theoreticians Justin Khoury and Amanda Weltman to formulate the so-called 'chameleon' model in 2004. They suggested that the main actor of dark energy is a particle which interacts strongly in a high vacuum, while being screened in 'denser' environments such as on Earth or even in the Milky Way. [...] In 2010, the researchers worked in an international team to come up with a method to detect chameleon interactions. Their setup consists of two parallel plates. If the density of the medium between these plates changes, there should be a change in the strength of the chameleon interactions, and thus either a reduction or an increase in the measured force between the plates. Overcoming numerous technical challenges, the researchers have designed and built the setup, and dubbed it the 'Casimir and non-Newtonian force experiment' (Cannex). A recent first test of the force sensor revealed that the detector can indeed reach the required sensitivity to measure chameleon interactions. In other words, Cannex will soon be able to completely rule out or prove the existence of chameleon interactions, and thereby help solve the dark energy puzzle. phys.org
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Spiders Ingest Nanotubes, Then Weave Silk Reinforced With Carbon
[Emiliano Lepore at the University of Trento in Italy] found a way to incorporate carbon nanotubes and graphene into spider silk and increase its strength and toughness beyond anything that has been possible before. The resulting material has properties such as fracture strength, Young’s modulus, and toughness modulus higher than anything ever measured. The team’s approach is relatively straightforward. They started with 15 Pholcidae spiders, collected from the Italian countryside, which they kept in controlled conditions in their lab. They collected samples of dragline silk produced by these spiders as a reference. The team then used a neat trick to introduce carbon nanotubes and graphene flakes into the spider silk. They simply sprayed the spiders with water containing the nanotubes or flakes and then measured the mechanical properties of the silk that the spiders produced. For each strand of silk, they fixed the fiber between two C-shaped cardboard holders and placed it in a device that can measure the load on a fiber with a resolution of 15 nano-newtons and any fiber displacement with a resolution of 0.1 nanometers. The results make for impressive reading. “We measure a fracture strength up to 5.4 GPa, a Young’s modulus up to 47.8 GPa and a toughness modulus up to 2.1 GPa,” say Lepore and co. “This is the highest toughness modulus for a fibre, surpassing synthetic polymeric high performance fibres (e.g. Kelvar49) and even the current toughest knotted fibers,” they say. technologyreview
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Synopsis: Coiling Viscous Jets
When poured onto toasted bread, honey can deposit in a variety of wavy patterns, like meanders, loops, or coils. Similar coiling patterns are seen in a variety of systems, ranging from jets for 3D printing to underwater optical fibers. But, to date, no theoretical models have been able to explain the complex features observed in experiments. Now, a team led by Pierre-Thomas Brun at the Massachusetts Institute of Technology, Cambridge, has formulated a theory that can predict the patterns created when a viscous fluid falls onto a surface. The authors modeled a thin thread of fluid landing onto a moving belt—a setup known as a fluid-mechanical sewing machine. They show that the system can be described by equations that depend on only a few “state” variables, such as the position where the jet hits the belt and the angle of the thread at that contact point. Like the thermodynamic state variables of a gas (temperature, pressure, or volume), these variables determine the present state of the system, as well as its future behavior. Depending on parameters like the height from which the fluid falls or the belt speed, the theory predicts that the system enters different phases, each of which corresponds to the formation of a specific configuration of loops and coils or, above a critical belt velocity, a straight line. The model successfully reproduces features observed in previously reported experiments. According to the authors, the theory could also be applicable to thin solid threads and might help guide the fabrication of patterned microstructures made of fiber or fabric. physics.aps.org