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
Does The Nearest Quasar Host A Black Hole Binary?
Our universe should be teeming with waltzing pairs of supermassive black holes. Yet they’re incredibly difficult to find. A research team has proposed a new way to find these dancing duos, but whether the method actually works is up for debate. At the center of every large galaxy (and many not-so-large ones too) sits a supermassive black hole millions or billions of times the mass of the Sun. And many of these galaxies have encountered and merged with at least one other galaxy. So it stands to reason that as galaxies meet and collide, their central black holes should meet, whirling around each other for at least a few hundred million years before they coalesce. [...] Theory says that, in a certain stage of their spiraling dance, the mutual orbit of two black holes will carve out a hole in the center of the accretion disk that surrounds and feeds them both. Since the center of the disk is the hottest part and produces the shortest-wavelength emission, if the center of the disk disappears, so does the hot gas and the short-wavelength emission it produces. In other words, a pair of feeding supermassive black holes will emit plenty of visible light, but very little ultraviolet. Yan and colleagues applied this idea to images of the nearest quasar, Mrk 231, whose light takes 575 million light-years to reach Earth. Astronomers have long known of this quasar’s strange light distribution — it produces far less ultraviolet radiation than it should. That’s been difficult to explain in terms of obscuring dust. (Dust tends to scatter away ultraviolet light, while letting optical light pass through, but not in quite the right way to explain this quasar’s spectrum.) Instead, Yan’s team shows that Mrk 231’s output matches what’s expected from the gap scenario. To do that, one black hole would have to outweigh the other, with respective masses of 150 million Suns and 4.5 million Suns, and they would orbit closely, separated on average by just 590 times the Earth-Sun distance and completing an orbit every 1.2 years. skyandtelescope
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Asteroid-Mining Plan Would Bake Water Out Of Bagged-Up Space Rocks
A new way to harvest asteroid resources is being eyed as a possible game changer for space exploration. The patent-pending innovation, called "optical mining," could allow huge amounts of asteroid water to be tapped, advocates say. This water, in turn, could provide relatively cheap and accessible propellant for voyaging spacecraft, lowering the cost of spaceflight significantly. [...] Sercel said that the optical-mining approach aims to excavate carbonaceous chondrite asteroid surfaces and drive water and other volatile materials out of this excavated material and into an enclosing, inflatable bag, all without the need for complex or impractical robotics. [Sercel formerly worked at NASA's Jet Propulsion Laboratory in Pasadena, California, and was a lead innovator for the NASA Solar Technology Application Readiness (NSTAR) ion propulsion system.] [...] Sercel and his colleagues are using their large solar furnace at the White Sands Missile Range in New Mexico to shed light andheat onto the idea. Since the late 1970s, researchers have used this furnace to simulate the sudden heat generated by a nuclear explosion. The furnace makes use of two primary sets of mirrors. One large, flat set can pivot around to seize the rays of the sun and direct them though a shutter system onto the second set of mirrors, which, in turn, focuses the light and heat onto the target. space.com
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Biology
U.K. Researcher Applies For Permission To Edit Embryo Genomes
A researcher in London has applied to the United Kingdom’s Human Fertilisation and Embryology Authority (HFEA) for a license to edit the genes of human embryos. Several techniques developed in recent years allow researchers to easily and accurately add, delete, or modify genes in cells. This has stirred debate about using genome editing in ways that would pass the changes on to future generations. The application filed with HFEA would involve only embryos in the lab, however, not any intended to lead to a birth. Many scientists say such lab experiments are crucial to understanding more about early human development, which could lead to new approaches to help infertile couples. The applicant, Kathy Niakan, a developmental biologist at the Francis Crick Institute in London, investigates the genes that are active at the earliest stages of human development, before it implants in the womb. Work with embryonic stem cells from mice and humans has suggested that some of the key genes active in this preimplantation period are different in humans and in mice. Niakan hopes to use genome editing to tweak some of the key genes thought to be involved and study the effects they have on human development. She has applied for a license from HFEA, which regulates the use of human embryos in the United Kingdom. The agency confirmed that it had received an application involving genome editing and said it would be evaluated under the agency’s standard rules. The experiments could be allowed under U.K. law. sciencemag.org
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World Has Lost 3 Percent Of Its Forests Since 1990
The globe's forests have shrunk by three per cent since 1990 - an area equivalent to the size of South Africa - despite significant improvements in conservation over the past decade. [...] Total forest area has declined by three per cent between 1990 and 2015 from 4,128 million hectares to 3,999 million hectares - a loss of 129 million hectares. Significantly, loss of natural forested area was double the global total at six per cent, while tropical forests took the hardest hit with a loss rate of ten per cent. Forestry expert at the University of Melbourne Professor Rod Keenan has been involved with the GFRA since 2003. For the 2015 Assessment, he headed a team of academics analysing the GFRA data for the UN's Food and Agriculture Organisation.
"These are not good stats," Professor Keenan said of the latest report. "We really need to be increasing forest area across all domains to provide for the forest benefits and services of a growing population. So there is more work to do."
biologynews.net
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Chemistry
Air Pollution Model Predicts 6.6 Million Deaths By 2050
Almost seven million people could die each year around the world because of outdoor air pollution unless strict emission controls are introduced, suggests a new study based on a global atmospheric chemistry model. Jos Lelieveld, of the Max Planck Institute for Chemistry in Mainz, Germany, and colleagues, combined the model with population statistics and health data to estimate premature deaths caused by pollutants such as ozone and fine particulate matter of less than 2.5µm, termed PM2.5, which arise from sources as diverse as coal power stations, agriculture and the burning of wood or dung in homes. The model shows that more than 3.3 million people a year die prematurely from inhaling the pollutants, from diseases affecting the heart, circulation and lungs. The largest impact on mortality worldwide is from the residential use of smoky fuels in parts of China and India for cooking or heating. In much of the US and some other countries, emissions from power generation and traffic contribute the most toward mortality from air pollution, while, perhaps surprisingly, in Europe and Russia the biggest culprit is agriculture. This, explains Lelieveld, is because ammonia released from fertilisers combines with gaseous emissions from traffic exhaust and power stations to produce sulphate and nitrate particles. rsc.org
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Citizen Scientists Gather Data To Influence Regulation Of Pollution
The boat crew huddles over the stagnant murk of Broad Creek on a hot summer morning. Plant debris and foam float on the second-most polluted tributary of Maryland’s South River, which feeds into the Chesapeake Bay. The skiff slows and drops anchor. The captain does a quick check on her position then orders the crew to haul up the anchor and reposition the boat. The craft is 8 feet from the spot where the volunteers have been taking water quality measurements for years. The sampling protocols are clear: The boat must anchor in that same spot, nowhere else. The team of staff scientists and volunteers know that to gather high-quality information on the water column, being spot-on with their GPS coordinates for this location in the creek is essential to maintain the trust of state agencies that accept their data. [...] SRF itself was created in 1999 by a loose-knit group of concerned residents watching the health of the river deteriorate. They banded together to form a Riverkeeper organization, which is part of the broader Waterkeeper Alliance network—a coalition of local environmental groups that keep an eye on fish kills, water quality, compliance with permits that limit soil erosion and runoff from construction sites, and other immediate local concerns. After years of careful examination and review of SRF’s data collection, scientists at MDE and its sister state agency, the Department of Natural Resources (DNR), have come to trust the volunteer-collected data. The environmental group files rigorous data quality plans with environmental regulators, coordinates scientific protocols with the natural resources agency during field visits, and provides training to volunteers. In doing so, SRF expands the scientific evidence available to natural resource managers on the Chesapeake Bay’s South River, according to state officials. acs.org
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Earth Science
Birds That Eat At Feeders More Likely To Get Sick, Spread Disease
BLACKSBURG, Va., Sept. 17, 2015 – Wild songbirds that prefer to eat at bird feeders have an increased risk of acquiring a common eye disease. In turn, these birds also spread the disease more quickly to their flock mates, according to an international research team led by Virginia Tech scientists. The researchers found that this feeding preference, rather than its social position in the flock, as previously thought, was more likely to result in a bird contracting the eye disease. The results of the study, funded by the National Science Foundation, were published Wednesday in the journal Proceedings of the Royal Society B.
"Our results suggest that in this species, a few individuals — those that like eating at feeders — are likely very important in driving disease epidemics," said Dana Hawley, an associate professor of biological sciences in the College of Science, a Fralin Life Science Institute affiliate and member of the Global Change Center at Virginia Tech. "If this is true for other wildlife species as well, we may be able to more effectively reduce disease by targeting these ‘high risk’ individuals."
The authors monitored the social and foraging behaviors of wild flocks of house finches, a common backyard songbird, and the spread of a naturally-occurring bird disease called Mycoplasmal conjunctivitis, which is similar to "pink eye" in humans but cannot be contracted by humans. Infected birds have red, swollen eyes that can lead to blindness, and ultimately, death, as a result of not being able to see. In the study, each bird was fitted with a unique chip containing a barcode that automatically recorded each time a bird visited one of the monitored bird feeders over an entire winter. When bar codes from different birds appeared at feeders around the same time, the researchers knew that those two birds were feeding together. virginiatech.edu
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Plants Migrate To Higher Altitudes Because Of Climate Change
The plants on the highest mountain in Ecuador have migrated more than 500 metres to higher altitudes during the last two centuries. This is determined in a new study, in which Aarhus University researchers compared Humboldt’s data from 1802 with current conditions. Although most of the world’s species diversity is found in tropical areas, there are very few studies that have examined whether tropical mountain species are affected by climate change to the same extent as temperate species. A new study has now determined that major changes have taken place during the last two centuries. By comparing the migration of plant communities on the Chimborazo volcano in Ecuador with historical data from 1802, Aarhus University researchers found an average upslope shift of more than 500 metres. The entire vegetation boundary has moved upwards from 4,600 metres to almost 5,200 metres. The main explanation for this dramatic shift is climate change over the last 210 years. In Humboldt’s footsteps The German scientist Alexander von Humboldt travelled to South and Central America around the 1800s to map the distribution of plants and to explore what determines the different vegetation boundaries. He collected plants over a period of many years, and his collections led to a better understanding of the link between climate and species distributions, which he described in several works. One of his most noteworthy works was the Physical Tableau, a cross-section of the Chimborazo inscribed with the names of the plants he found on the mountainside. [...] Upward shift of vegetation zones By comparing the two data sets, it became clear that not only the vegetation growth limit has moved, but also the vegetation zones defined by Humboldt. The individual plant species are now found more than 500 metres upslope than they were 210 years ago. These changes in the vegetation are more than expected as a result of today’s warmer climate. au.dk
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Physics
Physicists Show 'Molecules' Made Of Light May Be Possible
It's not lightsaber time, not yet. But a team including theoretical physicists from the National Institute of Standards and Technology (NIST) has taken another step toward building objects out of photons, and the findings hint that weightless particles of light can be joined into a sort of "molecule" with its own peculiar force. The findings build on previous research that several team members contributed to before joining NIST. In 2013, collaborators from Harvard, Caltech and MIT found a way to bind two photons together so that one would sit right atop the other, superimposed as they travel. Their experimental demonstration was considered a breakthrough, because no one had ever constructed anything by combining individual photons--inspiring some to imagine that real-life lightsabers were just around the corner. Now, in a paper forthcoming in Physical Review Letters, the NIST and University of Maryland-based team (with other collaborators) has showed theoretically that by tweaking a few parameters of the binding process, photons could travel side by side, a specific distance from each other. The arrangement is akin to the way that two hydrogen atoms sit next to each other in a hydrogen molecule.
"It's not a molecule per se, but you can imagine it as having a similar kind of structure," says NIST's Alexey Gorshkov. "We're learning how to build complex states of light that, in turn, can be built into more complex objects. This is the first time anyone has shown how to bind two photons a finite distance apart."
sciencedaily (h/t Shockwave)
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Dark Matter Hiding In Stars May Cause Observable Oscillations
Dark matter has never been seen directly, but scientists know that something massive is out there due to its gravitational effects on visible matter. One explanation for how such a large amount of mass appears to be right in front of our eyes yet completely invisible by conventional means is that the dark matter is hiding in the centers of stars. In a new study, physicists have investigated the possibility that large amounts of hidden mass inside stars might be composed of extremely lightweight hypothetical particles called axions, which are a primary dark matter candidate. The scientists, Richard Brito at the University of Lisbon in Portugal; Vitor Cardoso at the University of Lisbon and the Perimeter Institute for Theoretical Physics in Waterloo, Ontario, Canada; and Hirotada Okawa at Kyoto University and Waseda University, both in Japan, have published their paper on dark matter in stars in a recent issue of Physical Review Letters.
"Our work studies how dark matter piles up inside stars if the dark matter is composed of massive bosonic particles (axions are an example of such particles)," Brito told Phys.org. "Our results show that dark matter accretion by stars does not lead to gravitational collapse; instead it may give rise to characteristic vibrations in stars."
The researchers theoretically showed that, if numerous axions were to pile up inside normal stars, then the dark matter core would oscillate. The oscillating core would in turn cause the star's fluid to oscillate in tune with it at a specific frequency related to the star's mass, or at multiples of this frequency. For a typical axion mass, the oscillating stars would emit microwave radiation and might have observable effects.
"What oscillates is the fluid density and its pressure, but it's probably correct as well to say that the entire star is oscillating," Brito explained. "These are like sound waves propagating through the fluid, with a very specific frequency. Oscillations of this kind could, for example, lead to variations in the luminosity or in the temperature of the star, and these are quantities that we can measure directly."
phys.org
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