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
Brown Dwarfs Form Like Stars
Brown dwarfs, which bridge the gap between stars and planets, have been an exciting target for astronomers since their discovery in the mid-1990s. Since that time, we’ve observed and classified hundreds of these objects, but the details of how they form still remain an active area of research. The answer to a simple question, "Do brown dwarfs form in a method similar to stars, or do they form more like planets?" has eluded astronomers for decades. [...] Brown dwarfs are often referred to as "failed stars." Spanning a mass range of about 13 to 80 times that of Jupiter, brown dwarfs lack sufficient pressures and temperatures in their cores to ignite nuclear fusion, the process that generates starlight. They start off with surface temperatures about one-third that of our Sun, and most of that heat is generated as the cloud that forms the brown dwarf collapses under its own gravity. This makes the youngest brown dwarfs the hottest and brightest members of their class. As time passes they slowly cool, like fireplace embers — but over billions of years. The team targeted young brown dwarfs, because they haven't had a chance to cool off and are thus intrinsically brighter than older ones. The team was searching for jets, which astronomers commonly see coming from protostars but have not observed often from forming brown dwarfs. [...] Four of the young brown dwarfs showed radio emission due to jets, a hallmark of young, more massive stars. Jets are usually seen in young stars that are just forming, when the stellar magnetic fields are still very strong and the star is spinning rapidly. These magnetic fields can trap charged particles, supplied by strong protostellar winds, which emit radio waves as they accelerate around the fields. Observers have found that with normal stars, the strength of the magnetic fields, the amount of radio waves produced by particles spiraling through the jets, and the overall amount of proto-starlight produced are all related, with more massive (and therefore brighter) stars producing stronger magnetic fields and jets. [...]
“This is the first time that such jets have been found coming from brown dwarfs at such an early stage of their formation, and shows that they form in a way similar to that of stars," said Morata in an NRAO press release. "These are the lowest-mass objects that seem to form the same way as stars," he added.
skyandtelescope
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Giant Mystery Ring Of Galaxies Should Not Exist
Astronomers are constantly uncovering the "most distant," "most massive" or "most energetic" objects in our universe, but today, researchers have announced the discovery of a truly monstrous structure consisting of a ring of galaxies around 5 billion light-years across. The galactic ring, which was revealed by 9 gamma-ray bursts (GRBs), is located 7 billion light-years away and spans an area of the sky more than 70 times the diameter of a full moon. GRBs are thought to be detonated when a massive star reaches the end of its life. As the star implodes after running out of fuel, a black hole is formed and vast quantities of energy are blasted in collimated beams. Should Earth be aligned with these beams, an incredibly luminous signal can be observed and these beacons can be used to precisely gauge the distance to the GRB and the location of the galaxy that hosts it. [...] Astronomers believe these GRBs (and therefore the galaxies they inhabit) are somehow associated as all 9 are located at a similar distance from Earth. According to its discoverers, there's a 1-in-20,000 probability of the GRBs being in this distribution by chance — in other words, they are very likely associated with the same structure, a structure that, according to cosmological models, should not exist.
"If the ring represents a real spatial structure, then it has to be seen nearly face-on because of the small variations of GRB distances around the object's center," said Lajos Balazs, of Konkoly Observatory in Budapest, Hungary, and lead author of a paper published in the journal Monthly Notices of the Royal Astronomical Society. "The ring could though instead be a projection of a sphere, where the GRBs all occurred within a 250 million year period, a short timescale compared with the age of the universe."
space.com
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Biology
First Known Venomous Frogs Use Their Heads As Weapons
Venomous animals have toxins associated with delivery mechanisms that can introduce the toxins into another animal. Although most amphibian species produce or sequester noxious or toxic secretions in the glands of the skin to use as antipredator mechanisms, they have been considered poisonous rather than venomous because delivery mechanisms are absent. The frogs in question – the Greening’s frog (Corythomantis greeningi) and the Bruno’s casque-headed frog (Aparasphenodon brunoi) – produce potent toxins and also have a mechanism to deliver those harmful secretions into another animal using bony spines on their heads.
“Discovering a truly venomous frog is nothing any of us expected, and finding frogs with skin secretions more venomous than those of the deadly pit vipers of the genus Bothrops was astounding,” said Dr Edmund Brodie, Jr.
sci-news.com
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Butterflies Drug Ants, Turn Them Into Bodyguards
Even the sweetest relationships can turn sour. New research shows butterflies use nectar to drug unsuspecting ants with mind-altering chemicals. The Japanese oakblue butterfly (Narathura japonica) enlists the help of ants (Pristomyrmex punctatus) to stand guard and protect its growing caterpillars (pictured) from predators such as wasps and spiders. Sweetening the deal, the caterpillars pay for their bodyguards with a sugary reward secreted from nectar glands on their backs. But a study published online before print in Current Biology suggests this nutritious gift may be a Trojan horse. The team found that ants that consumed the nectar moved less and defended the caterpillars more aggressively, charging and running around them when they inflated specialized tentacles to signal distress. The researchers also found lower levels of dopamine—a signaling molecule that regulates movement and aggression in other insects—in the brains of nectar-eating ants. Ants that spent time near the caterpillars but didn’t eat the nectar were unaffected, suggesting that caterpillars manipulate the ants with chemicals dissolved in their nectar, not visual cues or airborne chemicals. This study calls into question whether the ants are willing participants in a collaborative arrangement or merely slaves to the whims of their caterpillar masters. The authors say the caterpillars may resort to manipulation because the relationship is unbalanced; ants can live without the nectar, but caterpillars are completely helpless without their ant guards. sciencemag.org
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Chemistry
Buckyballs Prove To Be A Magnetic Proposition For Copper
If you’ve ever tried to attract copper to a magnet and been disappointed, there’s a simple reason – copper isn’t magnetic. But a team of scientists from the UK, US and Switzerland has now discovered copper and manganese do show magnetism at room temperature if they are layered with buckminsterfullerene. The discovery has seemingly overcome an 80 year old theory of magnetism called the Stoner theory. In 1938 the British physicist, Edmund Clifton Stoner, theorised that a material can only be ferromagnetic if it meets the Stoner criterion, which depends on how easily electrons interact and are distributed in a material – a simple feat for the ferromagnetic iron, nickel and cobalt. The same is not true for copper and manganese according to the Stoner criterion, even though they occupy neighbouring spaces on the periodic table. However, the team based at the University of Leeds have given the two non-magnetic metals a helping hand by creating multilayer thin films of copper or manganese interspaced with C60 molecules. Fatma Al Ma’Mari and her colleagues found that the movement of electrons across this interface allows copper and manganese to overcome the Stoner criterion and exhibit a magnetic character. rsc.org
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Modern Circuits From An Ultrathin Material
Tomás Palacios, an electrical engineer at MIT, wants to make it possible to put electronics everywhere—to wrap buildings and highways with sheets of weather sensors, energy harvesters, environmental monitors, speakers, and other devices. Flexible circuits for these kinds of “ubiquitous” electronics don’t need to achieve the high performance of the rigid silicon chips used in computing, says Palacios. They just need to be durable, thin, flexible, and operate at low power. To this end, he and his team have made simple but state-of-the-art integrated circuits from ultrathin films—often called “2D”—of tungsten diselenide that are stable and relatively compact [...]. To get good performance and low power consumption from an electronic material, you have to be able to use it to make two kinds of transistors, those that conduct negative charges and those that conduct positive charges. Transistors are the electrical on/off switches at the heart of circuits. Complementary metal oxide semiconductor, or CMOS, technology combines both types of transistors in a single circuit. This enables engineers to pack a lot of computing punch in a small area and save power. To realize the world of ubiquitous electronics will require CMOS circuits made from novel 2D materials like tungsten diselenide. The key to building silicon CMOS circuits is a process called doping. Engineers replace atoms of pure silicon with foreign atoms to make the material better at conducting charge. But 2D materials are too thin for traditional doping. Another approach is to adsorb dopants at the material surface. But these dopants disperse over time. In the new study, Palacios figured out how to hold dopants at the surface to make stable transistors. Tungsten diselenide alone conducts electrons well enough to act as a negative-type transistor material. But positive transistors require doping. So the MIT group started with a known fluorinated organic dopant known as F4-TCNQ, and mixed it with a Plexiglas-like polymer. They spun this dopant-coating mixture onto the surface of a tungsten diselenide flake, holding the dopant in place. Finally, they used traditional semiconductor manufacturing to finish the transistors and connect them to make a basic CMOS circuit element called an inverter. The inverter’s voltage gain was 35, meaning it was able to amplify an incoming signal by 35 times. cen.acs.org
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Earth Science
Are Insecticides More Toxic Than We Think?
Insecticides that are sprayed in orchards and fields across North America may be more toxic to spiders than scientists previously believed. A McGill research team reached this conclusion after looking at changes in the behaviour of individual Bronze Jumping Spiders both before and after exposure to Phosmet, a widely used broad spectrum insecticide. It is a finding with far-reaching implications for agricultural production and ecosystem health. “Bronze jumping spiders play an important role in orchards and fields, especially at the beginning of the agricultural season, by eating many of the pests like the oblique-banded leafroller, a moth that attacks young plants and fruit,” says Raphaël Royauté, a former McGill PhD student whose study on the subject was published in Functional Ecology recently. “Farmers spray insecticides on the plants to get rid of these same pests, and it was thought that it had little significant effect on the spiders’ behaviours. But we now know that this isn’t the case.” The researchers discovered this fact by focusing on the way that exposure to insecticide affected the behaviour of individual spiders, including things like their ability to leap on prey and their interest in exploring new territory, both of which are crucial to their survival and to their role in keeping down pests. enn.com
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University Of Texas Study Underestimates National Methane Emissions At Natural Gas Production Sites Due To Instrument Sensor Failure
Abstract: The University of Texas reported on a campaign to measure methane (CH4) emissions from United States natural gas (NG) production sites as part of an improved national inventory. Unfortunately, their study appears to have systematically underestimated emissions. They used the Bacharach Hi-Flow® Sampler (BHFS) which in previous studies has been shown to exhibit sensor failures leading to underreporting of NG emissions. The data reported by the University of Texas study suggest their measurements exhibit this sensor failure, as shown by the paucity of high-emitting observations when the wellhead gas composition was less than 91% CH4, where sensor failures are most likely; during follow-up testing, the BHFS used in that study indeed exhibited sensor failure consistent with under-reporting of these high emitters. Tracer ratio measurements made by the University of Texas at a subset of sites with low CH4 content further indicate that the BHFS measurements at these sites were too low by factors of three to five. Over 98% of the CH4 inventory calculated from their own data and 41% of their compiled national inventory may be affected by this measurement failure. Their data also indicate that this sensor failure could occur at NG compositions as high as 97% CH4, possibly affecting other BHFS measurement programs throughout the entire NG supply chain, including at transmission sites where the BHFS is used to report greenhouse gas emissions to the United States Environmental Protection Agency Greenhouse Gas Reporting Program (USEPA GHGRP, U.S. 40 CFR Part 98, Subpart W). The presence of such an obvious problem in this high profile, landmark study highlights the need for increased quality assurance in all greenhouse gas measurement programs. wiley.com
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Physics
Fermilab Experiment Sees Neutrinos Change Over 500 Miles
Scientists on the NOvA experiment saw their first evidence of oscillating neutrinos, confirming that the extraordinary detector built for the project not only functions as planned but is also making great progress toward its goal of a major leap in our understanding of these ghostly particles. NOvA is on a quest to learn more about the abundant yet mysterious particles called neutrinos, which flit through ordinary matter as though it weren't there. The first NOvA results, released this week at the American Physical Society's Division of Particles and Fields conference in Ann Arbor, Michigan, verify that the experiment's massive particle detector—50 feet tall, 50 feet wide and 200 feet long—is sitting in the sweet spot and detecting neutrinos fired from 500 miles away. Scientists have sorted through millions of cosmic ray strikes and zeroed in on neutrino interactions.
"People are ecstatic to see our first observation of neutrino oscillations," said NOvA co-spokesperson Peter Shanahan of the U.S. Department of Energy's Fermi National Accelerator Laboratory. "For all the people who worked over the course of a decade on the designing, building, commissioning and operating this experiment, it's beyond gratifying."
Researchers have collected data aggressively since February 2014, recording neutrino interactions in the 14,000-ton far detector in Ash River, Minnesota, while construction was still under way. This allowed the collaboration to gather data while testing systems before starting operations with the complete detector in November 2014, shortly after the experiment was completed on time and under budget. NOvA construction and operations are supported by the DOE Office of Science. The neutrino beam generated at Fermilab passes through an underground near detector, which measures the beam's neutrino composition before it leaves the Fermilab site. The particles then travel more than 500 miles straight through the Earth, no tunnel required, oscillating (or changing types) along the way. About once per second, Fermilab's accelerator sends phys.org
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How Far Away Can You See Light From A Candle?
Can the unaided eye see the light from a single candle from 10 miles away? According to some claims on the Internet, the answer is yes – but now two scientists in the US have borrowed techniques from astronomy to show that a pair of binoculars would probably be needed. The story behind this work began high in the Andes one moonless night when a candle was lit on the Cerro Tololo Inter-American Observatory telescope catwalk. Somebody walked 400–600 m away and said the flame was as bright as the brightest stars in the sky. Nobody wrote down any numbers. [...] Don Carona, the director, instead offered a CCD camera to help measure the brightness of a flame against a highly visible magnitude zero star, Vega. The duo came up with a rule to describe the brightness relationship, adapting it to compare a candle flame to the faintest star an average unaided human eye can see: a magnitude-six star. Carona and Krisciunas then turned their attention back to candle spotting. Various sources on the Internet suggest that a candle is visible to the unaided eye at distances varying from 3.6 to 30 miles. Such claims might come from 1940s work out of Columbia University that looked at how the eye responds to flashes of light in a dark room. This is a different question, says Krisciunas, who adds that watching a candle flicker isn’t the same as observing flashes of light. By comparing the candle flame to a magnitude-six star, the researchers discovered that you would need 7 × 50 binoculars to see a candle 10 miles away. Furthermore, the farthest from which an average unaided human could see a candle is about 1.6 miles. physicsworld.com
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