Astronomy
ExoMars Trace Gas Orbiter Heads To Space
A Russian Proton rocket launched from the Baikonur Cosmodrome [March 14] with humanity's sole mission to Mars for 2016: the European Space Agency's ExoMars Trace Gas Orbiter.
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The Plans for ExoMars After arriving in Martian orbit and delivering the Schiaparelli lander to the planet's surface, the ExoMars orbiter will execute a series of looping elliptical orbits. Science operations are scheduled to begin at the end of 2017. ESA also plans to use the ExoMars orbiter as a communications relay for its 2018 ExoMars rover, and the orbiter is designed to operate until 2022.
The primary objective of this mission, a collaboration between ESA and the Russian space agency Roscosmos, is to search out evidence for trace gases in the Martian atmosphere. One elusive mystery on Mars is the source of trace amounts of methane spotted there from Earth. The gas could be the result of fresh volcanic eruptions or current biological processes. ExoMars will also test key technologies required to land a rover on Mars in 2018.
The ExoMars Trace Gas Orbiter carries a Color and Stereo Surface Imaging System (CaSSIS), a Fine Resolution Epithermal Neutron Detector (FREND), the Nadir and Occultation for Mars Discovery (NOMAD) infrared and ultraviolet spectrometer, and the Atmospheric Chemistry Suite (ACS). CaSSIS will scout out potential landing sites for the 2018 ExoMars rover, while NOMAD and ACS will observe sunlight filtered through the Martian atmosphere when they pass through twilight twice per orbit.
Meanwhile, down on Mars, the Schiaparelli lander will employ the DREAMS (Dust Characterization, Risk Assessment, and Environment Analyzer on the Martian Surface) meteorological package to monitor conditions on the surface. Sensors on DREAMS were designed by the Finnish company Vaisala, which has a long history of designing weather detectors for use on both Earth and space. The Curiosity rover also uses similar Vaisala weather sensors.
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Making The Case For An Ice Giants Mission
An armada of spacecraft keep a constant watch on the Red Planet. But the ice giants — Uranus and Neptune — were explored close up for a matter of days in the 1980s. Mark Hofstadter of NASA’s Jet Propulsion Laboratory hopes to change that. He’s been tasked with studying the merits and engineering requirements for a major mission to study these outer solar system worlds. The space agency’s head of planetary sciences, James Green, announced the potential mission in 2015 and said its final cost should be less than $2 billion. Past flagship missions include Cassini, Galileo, and Voyager. By the end of this year, Hofstadter’s team will create a list of science goals for a mission to Uranus and/or Neptune, and provide the space agency with an initial game plan for what such a mission would look like. The mission will compete to be the next in NASA’s flagship class, the biggest and most expensive kind, and — if it wins — the spacecraft will fly sometime between 2023 and 2035.
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In the decades since Voyager 2 made humanity’s only visit to each ice giant, these outer worlds have taken on increased significance. NASA’s Kepler space telescope has now shown Neptune-size worlds are abundant in the Milky Way. The exoplanet hunter has found roughly twice as many of these ice giants as it has Earth-sized worlds.
And yet, mysteries abound. Astronomers still don’t fully understand the structure of ice giants in our own solar system. Jupiter and Saturn are mostly gas. Earth and the terrestrial planets are mostly rock. But Neptune and Uranus are entirely different. They seem to consist of about one-third rock, one-third ice, and one-third gas. And that material doesn’t seem to be fully segregated.
“One way to think of these planets would be you can take a big, rocky planet several times the size of Earth, and then put 10 Earth masses of ocean around it, and then a little bit of hydrogen and helium on top,” Hofstadter says.
Biology
Sweet Corn Genes Related To Crowding Stress Identified
Plants grown in high-density or crowded populations often put more energy into growth and maintenance than reproduction. For example, flowering may be delayed as plants allocate resources to growing taller and escape competition for light. This sensitivity to crowding stress has been observed in some varieties of sweet corn, but other varieties show higher tolerance, producing high yields even in crowded conditions. A recent University of Illinois and USDA Agricultural Research Service study attempted to uncover the genetic mechanisms of crowding tolerance in sweet corn.
"We were trying to find genes that differentiate sweet corn hybrids that have potential to produce higher yields under crowding stress versus hybrids with lower yields under the same growing conditions," explains U of I crop science researcher Eunsoo Choe.
Choe and her team measured observable or phenotypic traits for high- and low-yielding hybrids under crowding stress; these included traits known to correlate with crowding stress, such as plant height, leaf area, and time to maturity. Other traits, such as yield, kernel mass, kernel moisture, and fill percentage were also measured. Lastly, the team extracted genetic material from the plants to explore correlations between gene expression patterns and measured traits.
"We found clusters of genes that were related to yield under crowding stress," says Choe.
Although gene expression patterns indicated each hybrid utilized unique mechanisms for tolerating crowding stress, the researchers did confirm a common genetic basis for the yield response in the six hybrids tested. Low-yielding hybrids had gene activities related to various stress responses while high-yielding hybrids utilized gene activities more directly related to carbohydrate accumulation.
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Spider Diet Goes Way Beyond Insects
Spiders eat insects. That’s why some of us are reluctant to kill spiders we find at home — we figure they’ll eat the critters we really don’t want around. But a new study reveals that the spider diet is far more diverse than we learned in elementary school. Spiders are insectivores, sure, but many also have a taste for plants.
Only one species of spider is known to be completely vegetarian. Bagheera kiplingi jumping spiders of Mexico survive mostly on bits of acacia trees, Science News reported in 2008. And while scientists have yet to find any other vegetarian species, plant-eating appears to be very common, particularly among jumping spiders and spiders that make webs outdoors.
Martin Nyffeler of the University of Basel in Switzerland and colleagues combed books and journals for reports of spiders consuming plant material. There is evidence of veggie-eating among more than 60 species of spiders, representing 10 families and every continent but Antarctica, the team reports in the April Journal of Arachnology.
Perhaps past scientists can be forgiven for overlooking the plant-eating behavior, as spiders can’t eat solid material. They have a reputation for sucking the juices out of their prey, but that’s not quite the right description. Instead, a spider covers its prey with digestive juices, chews the meat with its chelicerae and then sucks the juices in. This eating style means, though, that spiders can’t just cut a piece of leaf or fruit and chow down.
Some spiders feed on leaves either by digesting them with enzymes prior to ingestion (similar to prey) or piercing a leaf with their chelicerae and sucking out plant sap. Others, such as the vegetarian Bagheera kiplingi, drink nectar from nectaries found on plants or in their flowers. More than 30 species of jumping spiders are nectar feeders, the researchers found.
Chemistry
Newton’s Recipe For Alchemists’ Mercury Rediscovered
The document is a copy of a known text authored by another alchemist, written in Latin, as was common practice at the time. Its title translates as ‘Preparation of the [Sophick] Mercury for the [Philosophers'] Stone by the Antimonial Stellate Regulus of Mars and Luna from the Manuscripts of the American Philosopher’. It describes a process for making ‘sophick’ – short for ‘philosophic’ – mercury.
‘Philosophic mercury was [thought to be] a substance that could be used to break down metals into their constituent parts,’ explains James Voelkel, the CHF’s curator of rare books. ‘The idea is if you break the metals down you can then reassemble them and make different metals.’ The process was part of the effort to make the philosopher’s stone, he adds, a mythical substance that alchemists believed could turn lead into gold.
It is likely Newton used the text as a reference when conducting his own alchemical experiments, although it is unclear whether he ever tried to make sophick mercury. There is no mention of the process in his laboratory notebook, which is currently kept at the University of Cambridge in the UK. But Voelkel says it ‘would not have been out of character’ for him to attempt it.
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Alchemical anonymity
The author of the original sophick mercury paper was a well-known alchemist at the time known as Eirenaeus Philalethes. Historians now know that this was a pseudonym invented by the Harvard-educated chemist George Starkey, one of the US’s first published scientists. Starkey moved to England in 1650, and worked with some of the most eminent chemists of the time, including Robert Boyle.
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Although it is not possible to say exactly when it was written, Newton’s copy of Philalethes’ sophick mercury text may pre-date the first known printed version, which was published in 1678. ‘It’s probably the case that he was copying a manuscript that existed before the publication of the printed work,’ says Voelkel. ‘The manuscript he’s copying has at least one mistake in it. At some point the author writes the Latin word ‘ex’ which means ‘out of’ instead of ‘et’ which means ‘and’ – Newton recognises this as being a mistake and corrects it in square brackets. In the printed source this has been corrected.’
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Bread Mold For A Better Rechargeable Battery?
The researchers show for the first time that the fungus Neurospora crassa can transform manganese into a mineral composite with favorable electrochemical properties.
"We have made electrochemically active materials using a fungal manganese biomineralization process," says Geoffrey Gadd of the University of Dundee in Scotland. "The electrochemical properties of the carbonized fungal biomass-mineral composite were tested in a supercapacitor and a lithium-ion battery, and it [the composite] was found to have excellent electrochemical properties. This system therefore suggests a novel biotechnological method for the preparation of sustainable electrochemical materials."
Gadd and his colleagues have long studied the ability of fungi to transform metals and minerals in useful and surprising ways. In earlier studies, the researchers showed that fungi could stabilize toxic lead and uranium, for example. That led the researchers to wonder whether fungi could offer a useful alternative strategy for the preparation of novel electrochemical materials too.
"We had the idea that the decomposition of such biomineralized carbonates into oxides might provide a novel source of metal oxides that have significant electrochemical properties," Gadd says.
In fact, there have been many efforts to improve lithium-ion battery or supercapacitor performance using alternative electrode materials such as carbon nanotubes and other manganese oxides. But few had considered a role for fungi in the manufacturing process.
Ecology
Australia Slashes Funding On Climate Science
Scientists around the world have slammed Australia’s decision to slash its climate research programme — raising concerns about knock-on effects on developing countries. Australia’s Commonwealth Scientific and Industrial Research Organisation (CSIRO) is shifting its research focus to efforts to adapt to and mitigate the effects of global warming rather than understanding climate change through fundamental research, CSIRO chief executive Larry Marshall announced last month.
[...] In an email to CSIRO staff quoted by international news outlets, Marshall says that models have proved climate change, and we should now focus on solutions.
“That argument would be like removing the foundations of the house because you need to build a roof,” says Lisa Alexander, an associate professor in the climate change research centre at the University of New South Wales in Australia, and one of almost 3,000 people who signed an open letter to the Australian government protesting the cuts on 11 February. “CSIRO’s decision to slash climate research will severely curtail Australia's capacity to deliver on [key] promises of the Paris Agreement,” the letter says. This includes governments’ commitment to “assist developing countries by providing advice for adaptation […], a role that CSIRO and Australia have already begun in their investments in the Pacific Climate Change Science Program”.
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Desert Cactus Purifies Contaminated Water For Aquaculture, Drinking And More
Farm-grown fish are an important source of food with significant and worldwide societal and economic benefits, but the fish that come from these recirculating systems can have unpleasant tastes and odors. To clean contaminated water for farmed fish, drinking and other uses, scientists are now turning to an unlikely source -- the mucilage or inner "guts" of cacti.
The researchers present their work [Mar 13-17] at the 251st National Meeting & Exposition of the American Chemical Society (ACS). ACS, the world's largest scientific society, is holding the meeting here through Thursday. It features more than 12,500 presentations on a wide range of science topics. [...]
"We found there is an attraction between the mucilage of cactus and arsenic," says Norma Alcantar, Ph.D. "The mucilage also attracts sediments, bacteria and other contaminants. It captures these substances and forms a large mass or 'floc' that sort of looks like cotton candy. For sediments, the flocs are large and heavy, which precipitate rapidly after the interaction with mucilage."
The technology grew from century-old knowledge that mucilage from some common cacti can clean drinking water. Alcantar was first introduced to this process by her Mexican grandmother who described using boiled prickly pear cactus to capture particles in sediment-laced dirty water. The sediments sank, and the water at the top of the bucket became clear and drinkable.
Physics
In Space, Flames Behave In Ways Nobody Thought Possible
Recent tests aboard the International Space Station have shown that fire in space can be less predictable and potentially more lethal than it is on Earth. “There have been experiments,” says NASA aerospace engineer Dan Dietrich, “where we observed fires that we didn’t think could exist, but did.”
Here on Earth, when a flame burns, it heats the surrounding atmosphere, causing the air to expand and become less dense. The pull of gravity draws colder, denser air down to the base of the flame, displacing the hot air, which rises. This convection process feeds fresh oxygen to the fire, which burns until it runs out of fuel. The upward flow of air is what gives a flame its teardrop shape and causes it to flicker.
But odd things happen in space, where gravity loses its grip on solids, liquids and gases. Without gravity, hot air expands but doesn’t move upward. The flame persists because of the diffusion of oxygen, with random oxygen molecules drifting into the fire. Absent the upward flow of hot air, fires in microgravity are dome-shaped or spherical—and sluggish, thanks to meager oxygen flow. “If you ignite a piece of paper in microgravity, the fire will just slowly creep along from one end to the other,” says Dietrich. “Astronauts are all very excited to do our experiments because space fires really do look quite alien.”
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NASA scientists are especially excited about the potential applications for a bizarre, unprecedented type of combustion they observed in space this past spring: When certain types of liquid fuel catch fire, they continue to burn even when the flames appear to have been extinguished. The fuel combustion occurs in two stages. The first fire burns with a visible flame that eventually goes out. But shortly afterward, the fuel reignites, taking the form of “cool flames” that burn at lower temperatures and are invisible to the naked eye.
Scientists do not yet have an explanation for this phenomenon. But engineers say that if this chemical process could be duplicated on Earth, the result could be diesel engines that use cool flames to produce fewer air pollutants.
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The Science Of Watching Paint Dry
New research published today in the journal Physical Review Letters has described a new physical mechanism that separates particles according to their size during the drying of wet coatings. The discovery could help improve the performance of a wide variety of everyday goods, from paint to sunscreen.
Researchers from the University of Surrey in collaboration with the Université Claude Bernard, Lyon used computer simulation and materials experiments to show how when coatings with different sized particles, such as paints dry, the coating spontaneously forms two layers.
This mechanism can be used to control the properties at the top and bottom of coatings independently, which could help increase performance of coatings across industries as diverse as beauty and pharmaceuticals.
Dr Andrea Fortini, of the University of Surrey and lead author explained:
"When coatings such as paint, ink or even outer layers on tablets are made, they work by spreading a liquid containing solid particles onto a surface, and allowing the liquid to evaporate. This is nothing new, but what is exciting is that we've shown that during evaporation, the small particles push away the larger ones, remaining at the top surface whilst the larger are pushed to bottom. This happens naturally."
Dr Fortini continued, "This type of 'self-layering' in a coating could be very useful. For example, in a sun screen, most of the sunlight-blocking particles could be designed to push their way to the top, leaving particles that can adhere to the skin near the bottom of the coating. Typically the particles used in coatings have sizes that are 1000 times smaller than the width of a human hair so engineering these coatings takes place at a microscopic level. "
The team is continuing to work on such research to understand how to control the width of the layer by changing the type and amount of small particles in the coating and explore their use in industrial products such as paints, inks, and adhesives
