Astronomy
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The Weird Star That Totally Isn’t Aliens Is Dimming Again
There’s a star 1,300 light years away that has exhibited some of the strangest behavior ever seen: something dims 20 percent of its light, something that is beyond the size of a planet. It’s called KIC 8462852, but most people shorthand it Tabby’s Star, or Boyajian’s Star for its discoverer, Tabitha Boyajian.
Here’s the thing, though. Absolutely nobody knows why it’s dimming that much. It could be a massive fleet of comets or the debris of a planet. But it’s not giving off much infrared excess, which is a sort of "heat glow" from reflected starlight. And now, it seems to be dimming again, either helping or complicating the search for a solution.
Boyajian and co-investigator Jason Wright first put out the alert, hoping to garner observations from telescopes worldwide. They’re hoping at least one of telescope can grab spectra from the star to see what is causing the dimming.
So far the dimming is at 2-3 percent, meaning the transit of … something is just starting. Tabby’s Star has a dedicated telescope waiting to find such an event, so the big observation period could yield further clues to what’s occurring.
Ok, it’s time we tell you: some people think it’s aliens. The hypothesis, put forth by Wright, states that in the absence of a good hypothesis, all avenues must be explored, and that includes giant Dyson Swarm machines harnessing the power of the star. Gathering the spectra could help rule that out or bolster the case for that “all other avenues exhausted” scenario.
Astronomers Discover Magnetic Bridge Between Magellanic Clouds
For stargazers in the Northern Hemisphere, it’s easy to forget that the Milky Way is actively consuming two dwarf galaxies. Those in the Southern Hemisphere have a front row seat to watch our galaxy wreak havoc on the Large and Small Magellanic Clouds (LMC and SMC). But there’s more to the story — the dwarfs are not only gravitationally interacting with the Milky Way but with each other as well.
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Detecting the Invisible
Magnetic fields can be found within and around planets and stars but also on the scales of galaxies. We’ve detected galactic magnetic fields in both our own galaxy and in several other disk galaxies, but an extragalactic magnetic field is something else. This is the first magnetic field detected “outside” of a galaxy.
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The Magellanic Cloud Connection
Interpreting the data isn’t straightforward though. The Milky Way has its own magnetic field, as does Earth, the Sun, and several other planets in the solar system. So the team had to subtract out possible contributions from all other sources to isolate the effect due to the gas in the Magellanic Bridge alone. To do this, the team made assumptions and simplifications that may or may not be accurate, as magnetic fields still aren’t very well understood.
We know that the LMC and SMC had a close fly-by in the past. Astronomers can’t quite agree on exactly when or how close they got, but the event left both of them literally bent out of shape, their once spiral shapes now unrecognizable. The Magellanic Bridge is probably a remnant of this interaction, comprised of gas torn out of both galaxies as they passed by each other.
The authors of this paper argue that this newly discovered magnetic field is similarly made up of both galaxies’ magnetic fields, which were dragged into the bridge structure along with the gas. If true, this result would confirm the existence of a pan-Magellanic field — a magnetic field that spans both galaxies. The implications of such a field could speak to the history and future of the entire Magellanic system.
Biology
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Gladiator Games: Biodiversity Can Offer Protection To Weaker Species
If you pit a pair of gladiators, one strong and one weak, against each other 10 times, the outcome will likely be the same every time: The stronger competitor will defeat the weak. But if you add into the field additional competitors of varying strength levels, even the weakest competitors might be able to survive — if only because they’re able to find a quiet corner to hide.
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According to their results, common traits emerged among species that were able to dominate single competitors. But when additional species were added to the community, those competitive advantages meant less, allowing even the weakest species to maintain a foothold.
One key factor allowing these weaker species to survive was that the fungi exhibited many different competitive strategies; essentially, it turns out there is no overall “best” strategy. Instead, just as with the game of “rock-paper-scissors,” the success of any single strategy depended on what strategy the opponent used.
For instance, while the most competitive fungal species tended to grow fast (an effective offensive strategy), the researchers found that other species were more adept at playing defense. Some fungal species, for example, tended to remain fixed in one location, developing a dense biomass that became difficult to overcome even by the best offensive competitors. In so doing, these defensive fungi created a buffer between the stronger species and a weaker species. By contrast, losing even 20% or 30% of species can trigger an accelerated loss of biodiversity in a system.
“Our conclusion was that these ‘rock-paper-scissor’ relationships — in which each species has different strengths and weaknesses — actually negate the hierarchical gladiatorial competitions and allow really weak, really dissimilar species to survive,” said Maynard.
Newly Discovered Brain Network Offers Clues To Social Cognition
Scientists call our ability to understand another person's thoughts -- to intuit their desires, read their intentions, and predict their behavior -- theory of mind. It's an essential human trait, one that is crucial to effective social interaction. But where did it come from?
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The team used functional magnetic resonance imaging (fMRI) to identify those parts of the monkeys' brains that become active when the animals watched different kinds of videos.
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An exclusive social network
Most intriguingly, the team discovered that additional areas of the brain, far removed from those face- and body-selective areas, also lit up in response to social interactions. Digging deeper, the researchers even identified a portion of the network that responded exclusively to social interactions, remaining nearly silent in their absence.
"That was both unexpected and mind-boggling," says Freiwald, who explains that no other study has shown evidence of a network in the brain going dark when denied its preferred input.
This socially sensitive network is located in the same areas of the brain that are associated with theory of mind in humans -- areas that are similarly activated only when we reflect on the thoughts of others.
Chemistry
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Butanone
This week’s compound is technically known as butanone or methyl ethyl ketone – but most people first encounter it before technical names really mean much to them. Those who made plastic models of aeroplanes or similar would know it as polystyrene cement, and many others simply know it as the distinctive smell of whiteboard marker pens.
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Although polystyrene cement is marketed as a glue, it’s not. Rather than acting as a genuine adhesive – binding to the surface of the material – butanone is effectively a chemical welding agent. The plastic surfaces dissolve on contact, and then as the ‘glue’ evaporates away, they repolymerise into a new, bonded structure.
This means that the joints in plastic models are often almost as strong as the original material, and it won’t glue your fingers together if you’re careless like superglue does. It also won’t gum up natural brush bristles, and is unlikely to glue the lid to the tube or bottle it comes in. Although it works on a wide range of plastics, it won’t work on them all.
You might be more familiar with butanone as the solvent that makes the ink flow in the dry-erase marker pens we use to write on whiteboards, and gives them their distinctive sweet, sharp smell. It makes a good carrier for ink because it can dilute a wide range of pigment mixtures, and has low viscosity to allow the ink to flow.
Butanone’s use as a solvent is why it’s one of the most important commercially produced ketones –right up there with acetone, with which it shares many properties. It’s used in the production of paints, to make magnetic tapes for storing data and as a cleaner for electronic components. It can kill bacterial spores on surgical instruments and has even been used as a synthetic flavouring agent. It’s also listed in the United Nations convention against illicit traffic in narcotic drugs and psychotropic substances as a precursor for making narcotics – so there’s an underground demand in addition to the vast range of industrial uses.
Ecology
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Significant Groundwater Loss In California’s Central Valley During Recent Droughts
A new study from researchers at UCLA and the University of Houston reveals estimates of significant groundwater loss in California’s Central Valley during the recent drought and sparks questions of sustainability for the important agricultural area.
Researchers tracked net groundwater consumption in the Central Valley from 2002 to 2016, when a drought from 2007 to 2009 and a more severe drought from 2012 to 2016 hit the area. Published in Geophysical Research Letters, their findings estimate that a total of 16.5 cubic kilometers (4 cubic miles) and 40 cubic kilometers (9.6 cubic miles) of water were lost during between the 2007-2009 and 2012-2016 droughts, respectively.
The more recent drought accounted for more than 10 cubic kilometers (2.4 cubic miles) of water lost per year. Researchers attributed this to reduced precipitation and snow melt, a change in the type of crops being cultivated, and hotter temperatures.
“For perspective, the amount of material associated with the 1980 eruption of Mount St. Helens was about one cubic kilometer,” said Dennis Lettenmaier, the UCLA professor of geography who led the study. “So, we’re talking about 40 times that amount in the recent drought.”
Decreases in groundwater worsened even with a reduction in the amount of irrigated land, which decreased 7 percent from 2007–2009 compared to the 2012–2016 drought. Higher temperatures during the more recent drought period and a transition into high-value and thirsty tree crops accounted for most of groundwater loss between the two droughts, and more than offset the effects of a reduction in irrigated land, Lettenmaier said.
Vanishing Borneo: Saving One Of The World’s Last Great Places
Palm oil is the second-most important oil in the modern consumer society, after petroleum. Producing it is a $50-billion-a-year business. It’s in a multitude of the household products in North America, Europe, and Australia: margarine, toothpaste, shampoo, lipstick, cookies, Nutella, you name it. Doritos are saturated with palm oil. It’s what gives chocolate bars their appetizing sheen – otherwise, they would look like mud. Palm oil has replaced artery-clogging ghee as India’s main cooking oil. India is now the major consumer of this clear, tasteless oil squeezed from the nuts of the oil-palm tree, Elais guyanensis, originally from West Africa, but now grown pantropically, mainly within ten degrees north and south of the Equator.
Indonesia and Malaysia chose palm oil as their main economic engine after independence in the 1960s, and they together account for 85 percent of world production, which is expected to double by 2050. As oils go, palm oil gives you the best bang for your buck. Soy fields yield far less than rows of oil-palm trees and have to be replanted annually, while the palms keep bearing huge clusters of oil-rich nuts for 20 years, and can then be replaced. In 2015 17 million hectares of oil palm yielded a total of 62 million tons of oil, while the 120 million hectares planted in soy yielded 48 million tons. Palm oil doesn’t lose its properties when it’s heated, or become rancid at room temperature, and it has multiple industrial uses. It is the edible vegetable oil of choice and is not going away.
Borneo is ground zero for oil-palm devastation. Nowhere has more native rain forest been wiped out. The world’s third-largest island, Borneo’s lower 73 percent is in Indonesia— the territory of Kalimantan— and its upper portion consists of two states in Malaysia, Sarawak and Sabah, separated by the small, oil-rich sultanate of Brunei. Fifty percent of the lowland Borneo rain forest, which once covered all of the island up to 10,000 feet, is gone, but it’s still the third-largest in the world, after the Amazon and Equatorial Africa’s. It is part of the most ancient rain forest— forest, period— on earth: 130 million years old, more than twice as old as the Amazon’s, and has the greatest density of higher plant species, an estimated 15,000 flowering species. Each new botanical or entomological expedition comes back with new species. Some 20,000 insect species have been found in Sarawak’s Gunung Mulu National Park alone.
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The mountainous thickly jungled heart of Borneo was one of the last blank spots on the map, terra incognita, through World War II. The most remote bands of nomadic blowgun hunters were not reached by missionaries until the late l970s. Now they are all Christians and live in modern longhouses with TVs and electricity, but they still go off into the forest and hunt for days at a time, and a few bands still circulate in the forest and make new camps of raised pole huts every few weeks. Even the most isolated and traditional people in the central highlands are acutely aware of the modern world. Loggers are taking out their biggest trees, their rivers are being polluted and impounded by hydroelectric dams.
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The clearing and burning of peat forest has to be permanently banned. But on-the-ground verification that there is no further deforestation, that strips of forest have been left as wildlife corridors and along watercourses, is a huge problem, with all the corruption surrounding this lucrative commodity. Meanwhile species continue to be wiped out before they are even discovered, the most tragic type of extinction. Truly sustainable palm oil is still a long way off.
[Note from the Editor: I encourage readers to click through to this article. "This is a global battle for the cultural diversity of the tropics."]
Physics
World's Thinnest Hologram Promises 3D Images On Our Mobile Phones
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Just as a quick primer, holograpy essentially operates based on the principle of interference. A hologram is the product of the interference between two or more beams of laser light. So in a typical holographic device, a reference beam is focused directly on a recording medium, while an object beam is focused on the object that then hits the reference beam on the recording medium, creating an interference pattern.
In the device produced by the international team of researchers, a light source shines on the material, and the output light from the material and from the substrate has a phase difference. The phase contains the information on the contours of the original object. Human eyes and a CCD camera can capture the information and images.
“Integrating holography into everyday electronics would make screen size irrelevant—a pop-up 3D hologram can display a wealth of data that doesn’t neatly fit on a phone or watch,” said Min Gu, a professor at RMIT and co-author of the research, in a press release. "From medical diagnostics to education, data storage, defense and cyber security, 3D holography has the potential to transform a range of industries and this research brings that revolution one critical step closer.”