Astronomy
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Evidence Mounts For The Existence Of Planet Nine
In January of 2016, astronomers Mike Brown and Konstantin Batygin published the first evidence that there might be another planet in our Solar System. Known as “Planet 9”, this hypothetical body was estimated to be about 10 times as massive as Earth and to orbit that our Sun at an average distance of 700 AU. Since that time, multiple studies have been produced that either support or cast doubt on the existence of Planet 9.
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For the sake of their research, Doctors Carlos and Raul de la Fuente Marcos conducted calculations and data mining to analyze the nodes of 28 ETNOs and 24 extreme Centaurs (which also orbit the Sun at average distances of more than 150 AUs). What they noticed was that these two populations became clustered at certain distances from the Sun, and also noted a correlation between the positions of the nodes and the inclination of the objects.
This latter find was especially unexpected, and led them to conclude that the orbits of these populations were being affected by the presence of another body – much in the same way that the orbits of comets within our Solar System have been found to be affected by the way they interact with Jupiter. As De la Fuente Marcos emphasized:
“Assuming that the ETNOs are dynamically similar to the comets that interact with Jupiter, we interpret these results as signs of the presence of a planet that is actively interacting with them in a range of distances from 300 to 400 AU. We believe that what we are seeing here cannot be attributed to the presence of observational bias”.
Astronomers Just Discovered The Smallest Star Ever
This tiny new star, which is being called EBLM J0555-57Ab, is about 600 light-years from Earth, and has a comparable mass (85 Jupiter masses) to the estimated mass of TRAPPST-1. The new star, though, has a radius about 30 percent smaller. Like TRAPPIST-1, EBLM J0555-57Ab is likely an ultracool M-dwarf star.
The team used data from an experiment called WASP (the Wide Angle Search for Planets), which is typically used in the search for planets rather than stars, to look for new exoplanets. During their studies, they noticed a consistent dimming of EBLM J0555-57Ab’s parent star, which signified an object in orbit. Through further research to measure the mass of any orbiting companions, they discovered the object they’d detected was too massive to be a planet — it was instead a tiny star.
Though EBLM J0555-57Ab is incredibly small, it still has enough mass for hydrogen fusion, which powers the Sun and makes it Earth’s energy source. Just barely bigger than Saturn, the star has a gravitational pull 300 times stronger than Earth’s. If the star were much smaller (about 83 Jupiter masses), there wouldn’t be enough pressure in its center for the process to occur, and it would instead have formed as a brown dwarf, rather than a true star.
Biology
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Squirrels Have Long Memory For Problem Solving
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In the study, five squirrels were given a task identical to one they had tried 22 months earlier, in which they had to press levers to get hazelnuts. In that first experience, the squirrels improved with practice -- taking an average of eight seconds on their first attempt and just two seconds by the final time they tried it. Trying again for the first time in 22 months, they took an average of just three seconds to get a hazelnut.
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But the new research demonstrates a "very different form of memory," said co-author Dr Théo Robert, also of the University of Exeter.
"This is not just remembering where things have been left, it shows they can recall techniques which they have not used for a long time," he said. "It's also different from what we see in the wild because they're remembering things for longer than the few months of memory needed to find hidden food."
When presented with a version of the task that looked different but required the same technique to get hazelnuts, the squirrels showed a "neophobic" (fear of news things) response -- hesitating for more than 20 seconds on average before starting the task. But once they started it took them just two seconds on average to get a hazelnut, showing that they were able to recall and apply the technique they learned in the previous form of the challenge.
Walking Like Ants Gives Spiders A Chance
Ants are aggressive at defending themselves: They are well-armed with bites, stings and formic acid. Ant-mimicking jumping spiders -- Myrmarachne formicaria -- in contrast, can't do much more than run on their eight legs when attacked. Not surprisingly, insect predators tend to prefer spiders over ants, so appearing to be an ant confers significant protection.
Protective mimicry is a remarkable example of adaptive evolution: Moths can be colored like butterflies and grasshoppers may look like tiger beetles. While most mimicry studies focus on traits like color and shape, the researchers used multiple high-speed cameras and behavioral experiments to pinpoint how the spider's movements mimic ants.
Ant-mimicking spiders walk using all eight legs but pause frequently to raise their forelegs to mimic ant antennae. When walking, they take winding trajectories of about five to 10 body lengths, which made them look like ants following pheromone trails. While the researchers could see what the spiders were doing thanks to high-speed cameras, many potential predators have slower visual systems, so that to them the mimics appear to be moving just like an ant would.
Chemistry
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Aqua Regia
Way back in the 8th century AD, an alchemist by the name of Jabir ibn Al-Hayyan prepared the first recorded batch of aqua regia, a mixture of nitric and hydrochloric acid in a 1:3 ratio.
Named from the Latin for ‘royal water’, this volatile mixture turns from colourless to a fiery yellow-orange within a few seconds of being prepared. Adding to that dramatic effect, it also fumes vigorously. Because its components are so volatile, it is usually only mixed immediately prior to use. If left for a period of time, the concentrated nitric and hydrochloric acid react together in order to form products such as nitrosyl chloride and chlorine – neither of which you want hanging about in the lab.
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The primary use of aqua regia is the production of chloroauric acid, the electrolyte in the Wohlwill process for refining gold. Although gold is typically an inert metal, it will dissolve in aqua regia due to the unique action of nitric and hydrochloric acid. Nitric acid is a powerful oxidising agent, capable of converting small amounts of gold to its ionic form, Au3+. Once this ionic form is present in the solution, the hydrochloric acid provides a source of chlorine anions which react with the gold cations to form tetrachloroaurate(III) anions. As the reaction with hydrochloric acid is an equilibrium reaction favouring the formation of chloroaurate anions (AuCl4-), the gold ions are removed from solution making room for more oxidation to occur. And as the solution is so acidic, the chloroaurate anions are swiftly protonated to form chloroauric acid. Using this method, it is possible to produce gold with a jaw-dropping purity of 99.999%. Due to its reactivity and strength, aqua regia it can also dissolve platinum in a similar way.
Another common use for aqua regia is the deep cleaning the tubes used in nuclear magnetic resonance, or NMR, spectroscopy. It is very efficient at this as it is able to remove all traces of the paramagnetic element chromium, which can contaminate spectra and ruin research.
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Perhaps the most famous use of aqua regia occurred in 1940 at the Niels Bohr Institute in Denmark. Hitler had just invaded, and his forces were approaching rapidly. This meant that the chemist George de Hevesy had a problem – in his lab he had two Nobel prize medals, smuggled out of Germany on behalf of Max von Laue and James Franck. If they were found, they would all face severe punishment. Thinking fast, de Hevesy placed the medals into a solution of aqua regia and placed them on a shelf out of reach, leaving them to dissolve. When the Nazis entered the lab, they bypassed the beaker thinking it to be of no importance. Amazingly, when de Hevesy returned after the war he found the beaker undisturbed. He was then able to precipitate the dissolved gold and return it to the Nobel society, who then recast the medals in their original gold.
Ecology
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Why The World’s Rivers Are Losing Sediment And Why It Matters
In September 2011, after 20 years of planning, workers began dismantling the Elwha and Glines dams on the Elwha River in northwestern Washington state. At the time, it was the largest dam removal project in U.S. history, and it took nearly three years for both barriers to be dismantled and for the river to once again flow freely.
Over the course of their nearly century-long lives, the two dams collected more than 24 million cubic yards of sediment behind them, enough to fill the Seattle Seahawks football stadium eight times. And since their removal, the Elwha has taken back the trapped sediment and distributed it downstream, causing the riverine ecosystem to be rebuilt and transformed. Massive quantities of silt, sand, and gravel have been carried to the coast, resurrecting a wetlands ecosystem long deprived of sediment.
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Billions of cubic yards of natural river-borne sediment are trapped behind the world’s 57,000 large dams and countless small ones. This is material that otherwise would have been swept by river currents downstream and to the coast, where it would help build up marshes and other wetlands to act as a buffer against rising seas. Now, experts are searching for ways that this trapped sediment can be liberated and made available again to the rivers and estuaries to mitigate the loss of wetlands.
“Sediment allows coastal habitat to grow, adapt, and maintain itself while sea levels change,” says Robin Grossinger, a senior scientist with the San Francisco Estuary Institute, which is working with agencies and conservation groups to increase the extent of wetlands in the San Francisco Bay from 50,000 acres to 100,000. “It’s almost like it’s the food — the nutrients, minerals, and vitamins — these systems need to grow and adapt, and we are starving them of that.”
Chinese Lakes Less Polluted After Sanitation Clean-up
Concentrations of phosphorous fell by a third from 2006 to 2014 in 862 freshwater lakes in China, although they remain above clean water levels [...]. Phosphorous is vital to life, but high concentrations can trigger blooms of toxic algae that choke fish and other life. Man-made sources of phosphorous include waste water, livestock farming, aquaculture and chemicals.
Improved sanitation facilities are key
The current decline in the most populated areas is due to improved sanitation facilities such as pipelines, waste water treatment plants and improved rural toilets, says Yan Lin, [a researcher at the Section for Catchment Processes at the Norwegian Institute for Water Research (NIVA)].
Building good sanitation and sewage infrastructure is, according to Lin, key to stop phosphorous pollution, and these findings could guide other developing nations seeking ways to clean up vital freshwater resources.
Still high levels
The study, the first to have common measurements of phosphorous across China's lakes, showed the median level fell to 51 micrograms per 1 liter in 2014 from 80 in 2006. That is still high, however: A level of 25 is considered good quality water in European legislation.
Physics
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Mica Provides Clue To How Water Transports Minerals
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In a new study from the U.S. Department of Energy's (DOE) Argonne National Laboratory, in collaboration with the University of Illinois and Chicago and the University of Delaware, chemists have been able to look at the interface between water and muscovite mica, a flat mineral commonly found in granite, soils and many sediments. In particular, the researchers looked at the capture and release of rubidium - a metal closely related to but more easily singled out than common elements like potassium and sodium.
In the experiment, the researchers flowed a rubidium-containing solution over the mica, which caused rubidium atoms to replace the potassium that occurs naturally near the surface of the mica. Then the rubidium solution was replaced for one containing sodium, which in turn replaced the rubidium atoms.
According to Argonne chemist Sang Soo Lee, who led the study, the dynamics of the ion transport were largely controlled by electrostatic properties at the interface between the mica and the water. Essentially, the rubidium atoms "clung" to the mica's surface similarly to how lint clings to clothing. The strength of the clinging behavior was determined mainly by how many water molecules were in between the mica's surface and the rubidium - the fewer water molecules, the tighter the cling.
Lee and his Argonne colleague, chemist Paul Fenter, used Argonne's Advanced Photon Source, a DOE Office of Science User Facility, to observe the activity of the rubidium using a technique called resonant anomalous X-ray reflectivity. This technique allows scientists to probe the position of a single element at an interface.
"Essentially, it's like looking for a goldfinch in a tree, and using a technique that only shows you where yellow things are," Fenter said.