Jun 6, 2015
Now physicists at MIT have developed an experimental technique to simulate friction at the nanoscale. Using their technique, the researchers are able to directly observe individual atoms at the interface of two surfaces and manipulate their arrangement, tuning the amount of friction between the surfaces. By changing the spacing of atoms on one surface, they observed a point at which friction disappears.
Vladan Vuletic, the Lester Wolfe Professor of Physics at MIT, says the ability to tune friction would be helpful in developing nanomachines -- tiny robots built from components the size of single molecules. Vuletic says that at the nanoscale, friction may exact a greater force -- for instance, creating wear and tear on tiny motors much faster than occurs at larger scales.
"There's a big effort to understand friction and control it, because it's one of the limiting factors for nanomachines, but there has been relatively little progress in actually controlling friction at any scale," Vuletic says. "What is new in our system is, for the first time on the atomic scale, we can see this transition from friction to superlubricity."
Vuletic, along with graduate students Alexei Bylinskii and Dorian Gangloff, publish their results today in the journal Science.
Friction and force fields
The team simulated friction at the nanoscale by first engineering two surfaces to be placed in contact: an optical lattice, and an ion crystal.
The optical lattice was generated using two laser beams traveling in opposite directions, whose fields add up to form a sinusoidal periodic pattern in one dimension. This so-called optical lattice is similar to an egg carton, where each peak represents a maximum electric potential, while each trough represents a minimum. When atoms travel across such an electric field, they are drawn to places of minimum potential -- in this case, the troughs.
Vuletic then engineered a second surface: an ion crystal -- essentially, a grid of charged atoms -- in order to study friction's effects, atom by atom. To generate the ion crystal, the group used light to ionize, or charge, neutral ytterbium atoms emerging from a small heated oven, and then cooled them down with more laser light to just above absolute zero. The charged atoms can then be trapped using voltages applied to nearby metallic surfaces. Once positively charged, each atom repels each other via the so-called "Coulomb force." The repulsion effectively keeps the atoms apart, so that they form a crystal or lattice-like surface.
The team then used the same forces that are used to trap the atoms to push and pull the ion crystal across the lattice, as well as to stretch and squeeze the ion crystal, much like an accordion, altering the spacing between its atoms.
An earthquake and a caterpillar
In general, the researchers found that when atoms in the ion crystal were regularly spaced, at intervals that matched the spacing of the optical lattice, the two surfaces experienced maximum friction, much like two complementary Lego bricks. The team observed that when atoms are spaced so that each occupies a trough in the optical lattice, when the ion crystal as a whole is dragged across the optical lattice, the atoms first tend to stick in the lattice's troughs, bound there by their preference for the lower electric potential, as well as by the Coulomb forces that keep the atoms apart. If enough force is applied, the ion crystal suddenly slips, as the atoms collectively jump to the next trough.
"It's like an earthquake," Vuletic says. "There's force building up, and then there's suddenly a catastrophic release of energy."
The group continued to stretch and squeeze the ion crystal to manipulate the arrangement of atoms, and discovered that if the atom spacing is mismatched from that of the optical lattice, friction between the two surfaces vanishes. In this case, the crystal tends not to stick then suddenly slip, but to move fluidly across the optical lattice, much like a caterpillar inching across the ground.
For instance, in arrangements where some atoms are in troughs while others are at peaks, and still others are somewhere in between, as the ion crystal is pulled across the optical lattice, one atom may slide down a peak a bit, releasing a bit of stress, and making it easier for a second atom to climb out of a trough -- which in turn pulls a third atom along, and so on.
Read more at Science Daily
With its 3.4 billion base pairs, human DNA can compile a tremendous amount of information in a tiny space. All of the information stored is expressed using four nitrogenous bases: A, T, G and C. Researchers had previously been able to use the sequencing of these veritable molecular building blocks to reproduce a binary code. However, the technical limits of DNA made it necessary to develop the first synthetic polymer -- cheaper, more malleable and able to store binary information. This has now been achieved for the first time by a team of French scientists from the CNRS and Aix-Marseille Université.
Instead of using the four nitrogenous bases of DNA, in this study the researchers used three monomers . Two of these monomers represent the binary code numbers 0 and 1, and can be used interchangeably during synthesis. A third nitroxide monomer was inserted between the bits in order to facilitate the writing and reading of the coded sequence.
A short binary message is synthesized by hand, monomer by monomer on a growing chain. The operation takes approximately a day, but should be quicker once automated. Decoding is done by sequencing, in the same way that DNA has been decoded for decades. A mass spectrometer thus takes less than five minutes to decipher the information -- a duration also destined to be reduced in the short term.
While sequencing systematically destroys the polymer, it is also possible to erase the code at any time and without reading it, by exposure to temperatures above 60ºC or to a laser. Researchers showed that at room temperature, the polymer can be conserved for a number of months, and could even last several years given the molecule's stability.
Read more at Science Daily
Jun 5, 2015
Or rather, undersea eruptions used to go unnoticed. University of Washington researchers have installed an array of cutting-edge monitoring instruments in the vicinity of the Axial Seamount, an underwater volcanic mountain that’s about 300 miles off the coast of the Pacific and a mile beneath the ocean surface. In late April, that gadgetry enabled them to anticipate and then observe a eruption in real time, and to collect a massive amount of data on the event.
“It was an astonishing experience to see the changes taking place 300 miles away with no one anywhere nearby, and the data flowed back to land at the speed of light through the fiber-optic cable connected to Pacific City — and from there, to here on campus by the Internet, in milliseconds,” noted UW oceanography professor John Delaney in a press release.
The researchers, who are working in a larger effort sponsored by the National Science Foundation, got their first inkling that Axial was about to blow just before midnight on April 23, when eight seismometers installed at the site transmitted warnings that seismic activity in that area was going off the charts. The rate of tremors increased dramatically over the next 12 hours, to a rate of thousands per day.
Meanwhile, the center of Axial’s volcanic crater dropped by about 6 feet.
“The only way that could have happened was to have the magma move from beneath the caldera (the collapse of land following an eruption) to some other location,” Delaney said, “which the earthquakes indicate is right along the edge of the caldera on the east side.”
Axial Seamount’s latest eruption actually was predicted in advance by Oregon State University researcher Bill Chadwick and his colleague Scott Nooner at the University of North Carolina at Wilmington. It previously erupted in 1998 and 2011, when scientists captured a picture of a bizarre layer of undersea glass formed when molten lava from the volcano encountered the near-freezing seawater.
From Discovery News
The new species are types of antechinus, a bristly haired, mouselike marsupial that eats meaty meals such as spiders and insects. Every year, antechinus males fight each other tooth and claw so they can have sex with as many females as possible before dying.
After sex is complete, with some sprees lasting as long as 14 hours, stress hormones in males skyrocket, causing their immune systems to collapse, “and they all drop dead before the females give birth to a single baby,” lead study author Andrew Baker, a mammalogist at the Queensland University of Technology’s Science and Engineering department, said in a statement.
Until now, 10 species of this sex-crazed marsupial were known to science, with the first discovered in 1803. In the past three years, however, scientists have identified five new antechinus species, revealing the genus has more diversity than previously thought. Like the known antechinus species, the two most recently discovered species also spend two to three weeks a year in a testosterone-fueled mating marathon, the researchers said.
Scientists found one of the new species, the Tasman Peninsula dusky antechinus (Antechinus vandycki), in the remote areas of southeastern Tasmania. Researchers already knew about the other brown, furry marsupial, but didn’t realize it was its own species until now. Now named the mainland dusky antechinus (Antechinus swainsonii mimetes), the newbie lives in parts of New South Wales and Victoria in Australia.
However, A. vandycki faces challenges beyond surviving a mating frenzy: Loggers are tearing apart the animal’s habitat and may push the species into a threatened status, the researchers said. Moreover, three of the relatively new antechinus species, including A. vandycki,are also threatened by climate change; feral pests, such as cats and non-native foxes; and habitat loss, the researchers said.
“We discovered the Tasman Peninsula dusky antechinus not far from the old European settlement town of Port Arthur in Tasmania,” Baker said in the statement. “Most of its limited habitat falls within state forest, which is being logged.
“This species now apparently only lives in tiny, fragmented stands of intact forest that are under threat,” Baker added. “It’s a shame that mere moments after discovery, these little Tasmanian marsupials are threatened with extinction at human hands.”
In fact, Baker has already tried to place two of the other antechinus species he discovered — the black-tailed and silver-headed antechinus — on the state’s threatened species list.
“Both these species are found on remote mountaintops in southeast Queensland,” Baker said. “These species have already retreated to their misty mountain summits. In the face of ongoing climate warming, they have nowhere left to run.”
Read more at Discovery News
Drawn on a white-ground pyxis (a lidded cylindrical box that was used for cosmetics, jewelry, or ointments) the image shows an Amazon on horseback in a battle against a Greek warrior.
Much like the fictional warrior princess of the Amazons, the horsewoman is twirling a lasso.
“It is the only ancient artistic image of an Amazon using a lariat in battle,” Adrienne Mayor, a research scholar at Stanford University’s departments of classics and history of science, told Discovery News.
Mayor noticed the vase at the University of Mississippi Museum during research for her 2014 book “The Amazons: Lives and Legends of Warrior Women across the Ancient World.”
Created between 480 and 450 B.C. in Athens, the image is attributed to the Sotheby painter.
“The vase would have held a Greek woman’s intimate make-up or jewelry. The images on the box suggest that women enjoyed scenes of Amazons getting the best of male Greek warriors,” Mayor said.
According to the researcher, the suspenseful scene of a Greek male about to be lassoed by a powerful foreign warrior woman was exotic and also subversive, a surprising twist on traditional Greek women’s roles.
The Amazon is portrayed in a dynamic action just before roping her victim. She looks back over her shoulder at the lasso she is swinging while the Greek man crouches under his shield with a spear.
“The rest of her rope, painted purple like her shoes, is coiled around her waist, and she correctly holds the lariat’s loop near the knot,” Mayor said. “Her technique is accurate for roping something straight ahead,” she added.
She noted the Amazon has her battle-axe ready to dispatch her victim.
According to Mayor, the vase decoration is evidence that the painter and his audience were familiar with descriptions of horse-riding Scythian warrior women using lariats.
Ancient Greek and Roman historians describe Scythian mounted archers skillfully using lassos in warfare.
For example, Herodotus reported that 8,000 nomadic steppe riders armed with daggers and braided leather lariats joined the army of Persian king Darius in 480 B.C.
Several other sources told how Scythian skirmishers threw rope nooses and wheeled their horses around to entangle their enemies.
Roman geographer Pomponius Mela, who wrote around 43 A.D., also reported that warrior women of the northern Black Sea region were experts with the lasso.
Read more at Discovery News
However, the explosive final moments of these elusive stellar outcasts are hard to find.
But in new research to be published in the Astrophysical Journal, the neighborhoods of a handful of odd Type Ia supernovae between the galaxies inside bustling galactic clusters have been studied by the Hubble Space Telescope, revealing that these specific stellar detonations were triggered in the depths of “intracluster” space and not in bustling stellar metropolises.
Discovering supernovae far from their host galaxy is extremely rare. In fact, because supernova events can be millions or billions of light-years from Earth, the host galaxy or star cluster hosting a supernova can be too dim for us to see; the supernova becomes the only visible indicator of that galaxy’s existence.
Type Ia supernovae are thought to be spawned in stellar binaries, where material is siphoned from one, less massive partner to the other, usually a dense white dwarf. When the stellar plasma reaches a threshold, the system detonates and produces a supernova.
“The companion was either a lower-mass white dwarf that eventually got too close and was tragically fragmented into a ring that was cannibalized by the primary star, or a regular star from which the primary white dwarf star stole sips of gas from its outer layers,” said lead researcher Melissa Graham, of the University of California, Berkeley. “Either way, this transfer of material caused the primary to become unstably massive and explode as a Type Ia supernova.”
Using Hubble, Graham’s team zoomed in on the sites of 3 apparently galaxy-less supernovae that occurred between 2008 and 2010. They found that these examples were indeed exiled stars that died alone at least 300 light-years from the nearest stellar neighbor. That’s almost 100 times the distance between our sun and its nearest neighbor, Proxima Centauri, which is over 4 light-years away.
Before these stars died, it’s hard not to ponder whether they hosted planets, as most of the stars in our galaxy are thought to contain. The night sky seen from any of these hypothetical planets orbiting “intracluster” stars would appear very different than the sky as seen from Earth, however, reminding Graham, who is an avid sci-fi fan, of particular science fiction imagining of one such world:
The solitary worlds reminded study leader Melissa Graham … of the fictional star Thrial, which, in the Iain Banks novel Against a Dark Background, lies a million light years from any other star. One of its inhabited planets, Golter, has a nearly starless night sky. — UC Berkeley press release.
“It would have been a fairly dark background indeed, populated only by the occasional faint and fuzzy blobs of the nearest and brightest cluster galaxies,” said Graham.
Of course, any planets orbiting these vagabond stars would have likely been destroyed, or at least severely sterilized, by the resulting Type Ia supernovae.
Read more at Discovery News
|"What's up, Doc?" asked no giant weta ever. That noise is trademarked.|
Weta are New Zealand’s most iconic bugs, around 70 known species that range from the big ones like the giant weta to other smaller varieties: the “tree,” “tusked,” “ground,” and “cave” weta, all equally excellent in their own unique ways. They all differ in size and features, but all are products of the strange evolutionary history of New Zealand, an island that’s enjoyed relative isolation. That is, until humans arrived and started making a mess of things.
If the weta look to you like crickets addicted to protein shakes, you’re not far off. They are indeed in the same family, but in their long isolation in New Zealand, the weta have gotten weird. None can fly, for instance, because there have historically been no terrestrial mammals here. “That’s the critical part,” says biologist Priscilla Wehi of New Zealand’s Landcare Research, who you can see below calmly acting as a tree weta’s chew toy. “What that meant was that, as with a lot of our birds, being flighted wasn’t so important.”
In part, it’s flightlessness that has allowed the giant weta to grow to such an extraordinary size. But there are limits to such growth, and the weta may well be pushing them. This is because insects don’t breathe like humans do. Instead of lungs, they have holes in their exoskeleton that open to tubes branching through the insect’s body, providing every cell with oxygen. This all works well and good, but it limits the insect’s size, since only so much oxygen can get deep in the critter as it dissolves into tissues.
But some 300 million to 400 million years ago, when oxygen levels were bonkers (35 percent of the atmosphere compared to 21 percent today), bugs grew huge—like dragonflies the size of seagulls and millipedes over 6 feet long—because more oxygen meant the gas could diffuse deeper into their huge bodies. Scientists think the oxygen plummeted to current levels when a giant space maid vacuumed it out (though it probably had more to do with a drop in sea level and drying out of land masses), so these days insects are a more reasonable size.
Not So Giant, But Definitely More Bitey
The other varieties of weta may be dwarfed by the giant type, but they’re no less extraordinary. The male tree weta, for instance, is equipped with gigantic mandibles, which it uses to battle other males for the right to mate, building harems of up to eight females. “They sometimes inflict damage on each other,” says Wehi, “which can even result in the loss of a leg or some other bit of their body, and they might try to throw the other male weta from the tree.”
|The impressive jaws of the tree weta.|
There’s also the tusked weta, which like the tree weta fights for females, only its weapons do indeed look a bit like elephant tusks. And down in the undergrowth lives another type, the aptly named ground weta. This one digs burrows and waits there for other insects to traipse by, then pounces. Still another has adapted to life in caves, packing extra-long antennae it uses to feel around in the darkness.
All species have brilliantly adapted to life in island isolation. And accordingly, many are in trouble.
Humans arrived in New Zealand in the 13th century, but they didn’t arrive alone. Stowed away was the Pacific rat, which found a bounty of tasty creatures that had evolved there in total absence of mammals (save for bats). Fast forward to the 19th century, when Europeans brought the rest of the mammals that would lay waste to New Zealand’s endemic wildlife: cats, stoats, other types of rats. Now half of the island’s native bird species are gone.
|A weta would never do the can-can, because that’s trademarked too. It would, however, lift up its spiny leg in order to ward off predators.|
A rather more ambitious approach is to build sanctuaries on the mainland. Crews have fenced off an entire mountain and trapped out all of its mammalian predators. Endemic species normally ravaged by mammals were then introduced to live with fewer hassles, just like they used to. Weirder still, a small population of giant weta has survived on a farm in a patch of a nasty prickly plant called gorse. The thicket, it seems, is impenetrable for rats—not to mention human researchers. “So you can probably imagine the poor people who have to go in and try to count their population,” Wehi says.
Read more at Science Daily
Jun 4, 2015
Changes are already afoot in the oceans. Roughly 93 percent of the heat trapped by human greenhouse gas emissions is ending up in the world’s seas and already contributing to changes from slowing plankton growth to recent incursions of tuna near Alaska, thousands of miles from their normal range.
If greenhouse gas emissions continue to build, that heat could create wholesale changes for the vast majority of the world’s oceans (which, of course, make up the vast majority of the world).
The findings come from a new study published in Nature Climate Change, which looks at future climate projections and the distant past when 60-foot sharks prowled the oceans, sea levels were 100 feet higher and the globe was about 11°F hotter. Oh, and humans weren’t around, either.
There’s one major similarity between our current period and 3 million years ago, a period known as the Pliocene: the amount of greenhouse gas concentrations in the atmosphere. It’s a trait that makes it a powerful comparison for what the next century may have in store unless humans cut their greenhouse gas emissions.
“What we have found is that if we constrain global warming by less than 2°C, ocean changes will be relatively benign on the global scale,” Grégory Beaugrand said. “But if we are above this threshold, we will have a huge reorganization of marine biodiversity.”
Beaugrand is an ocean researcher at the French National Center for Science Research and lead author of the new report, which shows that if greenhouse gas emissions continue unabated, up to 70 percent of world’s oceans could see biodiversity shifts unprecedented in modern times.
The findings show that species could vacate the tropics as warming water send species poleward with nothing in place to fill their void. For species already living near the poles, they would face a wave of invaders that could outcompete them for resources. Warming waters would eventually make any suitable habitat disappear. The outcome in both cases is the distinct possibility of extinction.
“It (the study) demonstrates the capacity for huge marine biomes to be fundamentally reorganized and disturbed, and shows us there are real differences between moderate warming and severe warming,” Sarah Moffitt, a postdoctoral researcher at the University of California, Davis’ Bodega Marine Laboratory, said.
The study takes a macro-level view so its unclear how specific species would react to the changes. But everything in the sea from crustaceans to cetaceans would have to contend with these shifting conditions, the effects of which would be felt on land as well. Fisheries and aquaculture contributed $274 billion to the world’s GDP in 2012, the most recent year with data available. As species move or die off, people that rely on them for livelihoods will have to respond.
“We will have species that will disappear but some others will take their place,” Beaugrand said. “But fishermen, usually they are adapted to a certain type of species. They will have to re-adapt to a new type of species and adaptation is expensive.”
Signs of warming are already floating across the oceans. Recent sightings of tuna off the Alaska coast, thousands of miles from their usual habitat, made headlines earlier this year as record-breaking warm water spread up the West Coast. The cause is likely natural but it could be a sign of things to come.
Read more at Discovery News
Remains of (Regaliceratops peterhewsi) were found in Alberta, Canada, according to a paper published in the latest issue of the journal Current Biology. The newly found species, which lived 70 million years ago, was closely related to the iconic dino Triceratops.
"The specimen comes from a geographic region of Alberta where we have not found horned dinosaurs before, so from the onset we knew it was important," co-author Caleb Brown of the Royal Tyrrell Museum of Palaeontology said in a press release.
"However, it was not until the specimen was being slowly prepared from the rocks in the laboratory that the full anatomy was uncovered, and the bizarre suite of characters revealed," he continued. "Once it was prepared it was obviously a new species, and an unexpected one at that. Many horned-dinosaur researchers who visited the museum did a double take when they first saw it in the laboratory."
The shield-like feature, which Brown described as a halo of large pentagonal plates radiating outward, gave this dinosaur a tribal leader look. When the facial horns are factored in, "The combined result looks like a crown," he said.
Past studies have speculated that features like this were probably used for defense, intimidation, visual communication, species recognition or attracting the opposite sex. One thing for certain is that the facial horns could have inflicted some serious damage to anyone who dared to anger this large animal, so defense and mating displays (such as fighting over coveted partners, as many horned animals do today) surely were two functions.
Hellboy's discovery was equally jarring. Geologist Peter Hews first spotted the dinosaur's fossilized bones sticking out of a cliff along what is now the Oldman River.
Aside from its uniqueness, the dinosaur is important for what it suggests about the evolution of horned dinosaurs. It has long been known that such dinos fall into one of two groups: the Chasmosaurines, which had a small horn over the nose, larger horns over the eyes, and a long frill; and the Centrosaurines, characterized by a large horn over the nose, small horns over the eyes, and a short frill.
"This new species is a Chasmosaurine, but it has ornamentation more similar to Centrosaurines," Brown said. "It also comes from a time period following the extinction of the Centrosaurines."
Hellboy's anatomy and the time in which it lived strongly suggest that the two groups of horned dinosaurs independently evolved similar features. This is known as convergent evolution.
Read more at Discovery News
In 2006, Greenland’s North Lake, a 2.2 square-mile (5.6 square kilometers) supraglacial meltwater lake, drained almost 12 billion gallons of water in less than two hours. In a study published two years later, researchers determined that this astonishing phenomenon is possible because giant hydro-fractures(water-driven cracks) can form directly beneath the lake basin and stretch down to the bed of the ice sheet, emptying the lake of water. But just how these fractures developed has been unknown — until now.
In the new study, published today (June 3) in the journal Nature, scientists using GPS technology discovered that the hydro-fractures form from tension-related stress caused by movements of the ice sheet. These movements are, in turn, triggered by the trickling meltwater.
The new research may help scientists better understand how much the ice sheet is contributing to sea level rise, researchers say.
Most of Greenland’s supraglacial lakes drain slowly when superficial streams route water into nearby, permanent crevasses or moulins (vertical conduits or shafts in a glacier). Fairly recently, however, satellite images showed that about 13 percent of the lakes drain quickly, emptying completely within 24 hours.
“The images would show the lake there one day, and gone the next day,” said first author of the new study, Laura Stevens, a glaciology doctoral candidate with the Massachusetts Institute of Technology/Woods Hole Oceanographic Institution (MIT-WHOI) Joint Program. “So we’ve known for the last 10 to 15 years that the water could disappear quickly.”
The 2008 research, led by Stevens’ co-author Sarah Das, a WHOI geological scientist, showed that temporary hydro-fractures could cause rapid lake drainage on an unprecedented scale. But that research was unable to determine what triggered the cracks in the first place. Two other, similar studies of different rapidly draining supraglacial lakes were also unable to identify what caused the hydro-fractures.
“The coverage of GPS stations was not dense enough,” Stevens told Live Science. “This study goes beyond previous studies on the lakes, because we have 16 GPS stations, as opposed to one or four.”
When meltwater in the summer drains to the bed from the ice surface through crevasses or moulins, it can cause the area within and around the lake basin to be “jacked up,” Stevens said. Additionally, it can decrease the surface area of the ice-sheet bed that’s in contact with the underlying bedrock, lubricating the bed and making it easier for the bed to move horizontally.
Placed around North Lake, the team’s 16 GPS stations recorded these two types of movements — called uplift and slip — between 2011 and 2013. This provided an in-depth perspective on the meltwater injected into the bed before, during and after the yearly drainages.
“We found that before we get the main expression of the lake drainage, there is a period of time (about six to 12 hours) where uplift and slip increase,” Stevens said. “That motion is enough to take the surface of the ice sheet and put portions of it in high tension that allows cracks to start forming.”
The study provides a clearer picture of the amount and location of the meltwater that travels down to the ice-sheet bed, which could help scientists better understand how fast the ice sheet flows during the summer, Stevens said.
Read more at Discovery News
Persistent strains of microbes have been discovered in spacecraft clean rooms. In 2014, Russian reports emerged of plankton surviving on the exterior of the International Space Station, a claim that NASA officials objected to for lack of evidence.
Still, understanding how well microbes can survive in space is of importance when sending out orbiters or landers around bodies that might present the right conditions for life, such as Mars. Scientists want to be careful to avoid contaminating other worlds with life from our own. And microbes' resilience to outer space enhances the prospects of panspermia, in which life can be seeded between planets via meteors and other traveling bodies.
This basis formed part of the rationale for a study led by Rocco Mancinelli, a senior research scientist at the Bay Area Environmental Research Institute, a nonprofit space and atmospheric science research group.
"Results from of this study are relevant to understanding the adaptation and evolution of life," Mancinelli wrote in an e-mail to Astrobiology Magazine.
His results were published in the January issue of the International Journal of Astrobiology in the article, "The affect of the space environment on the survival of Halorubrum chaoviator and Synechococcus (Nägeli): data from the Space Experiment OSMO on EXPOSE-R."
Finding the Limits
Part of Mancinelli's research focuses on microbe-environment interactions, specifically looking at the environmental limits in which organisms can live. One of his research interests includes the vacuum of space, which also is subject to extreme ultraviolet radiation from the sun, since there is no atmosphere to filter it out.
In his experiment, Manicelli took pure cultures of two salt-loving microbes, Halorubrum chaoviator and Synechococcus nägelli, from solid salt crusts and grew them. After drying them, some of the samples were sent to the International Space Station's external platform space exposure facility, called EXPOSE-R. Those microbes remained on the exterior for nearly two years. Other microbes were held back on Earth as control samples.
Surprisingly, some of those in space survived, Mancinelli said.
"Those organisms that were exposed to only the space vacuum all survived. Those exposed to high doses of ultraviolet radiation died, those exposed to lower doses of UV showed some survival," he said.
One large implication is the possibility that microbes could move around the solar system, he added.
"In other words, if even somewhat protected from UV, the organisms will survive a journey to another planet or moon in our solar system," he said.
What Kinds of Transfers?
There are numerous examples of planetary pieces from Mars moving over to Earth, specifically in a class of meteorites called SNCs (Shergottites, Nakhlites, Chassignites), which are blasted off the Martian surface during meteorite impacts.
That said, the typical time to move between the planets is millions of years, making the result "irrelevant" if they were SNCs, Mancinelli said. Microbes could, however, survive in meteorites with a transit time of a few years, providing they are shielded from UV radiation.
Read more at Discovery News
“This was a fun briefing: My science advisor just showed me this Hubble shot of the most crowded place in our galaxy,” wrote the President, with a dazzling Hubble Space Telescope observation of the Arches Cluster, located some 25,000 light-years away toward the center of our galaxy, attached.
President Obama is a well-known advocate for the sciences, STEM and science outreach, but this tweet didn’t focus on a specific policy or the White House Science Fair, this was just a guy (who happens to be the leader of the United States), looking up in wonder.
The story behind the tweet became apparent on Thursday morning when the President’s Chief Science Advisor John P. Holdren issued a White House statement. It just so happens that this particular observation, which was a part of an “ad-hoc” note he sent to White House staff, resonated with the President.
“Today’s morning report from NASA contains a Hubble photo I thought worth sharing,” Holdren wrote in the White House briefing. “The astonishing density of stars — most of which, we now know, have planets — really does make one wonder whether there’s anybody else out there. And this is just one piece of our own galaxy. There are an estimated 100 billion other galaxies in the observable universe. Enjoy!”
The Hubble Space Telescope is still going strong 25 years after it was launched by Space Shuttle Discovery’s crew in 1990 and this observation of the densely-packed stars in the Milky Way’s core is just one of the million images taken by Hubble to date. But how densely packed is this star cluster?
“The Arches cluster is so dense that in a region with a radius equal to the distance between the sun and its nearest star there would be over 100,000 stars! At least 150 stars within the cluster are among the brightest ever discovered in the Milky Way,” Holdren added.
The observation in question was released by NASA and the European Space Agency on May 29.
As noted by Holdren, it’s images like these that really put things in perspective, and makes us question our place in the universe and whether there is life elsewhere. Astronomy is a profound science; it has the ability fire-up our sense of wonder and question our very existence. By looking into the furthest-most reaches of the universe, we are actually seeking answers to questions we didn’t know we had about our own existence. Humanity can be very myopic, we only really care about what’s happening down here on this tiny speck of life-giving sand, but the possibilities the universe provides makes us want to push the envelope, to look out further, to explore.
Read more at Discovery News
Jun 3, 2015
The fish, which is the climbing perch Anabas testudineus, is on the move now, according to a press release issued by James Cook University (JCU). It has already traveled south from Papua New Guinea towards Australia, establishing itself on the Torres Strait Islands of Boigu and Saibai.
This video shows the fish in action at another site:
The species could be nicknamed “Superfish” because of its ability to survive incredible hardship.
When water dries up, the fish can drag itself from place to place, surviving for 1 to 6 days with zero water whatsoever. Mammal-like lungs allow it to breathe air while on land, in addition to its anatomy suited for water dwelling.
Its hardiness gives it an edge over most other fish, such that it can outcompete native species. Once it becomes established in a region, it can wreck havoc on the existing ecosystem, the researchers suggest.
The fish is so sturdy that it can hibernate in the mud of dried-up creek beds for up to six months. When swallowed by larger predators, the fish cleverly swells up its body, often blocking the throat of the predator, which may either choke or starve to death.
The climbing perch is a freshwater fish, but researchers are learning that even saltwater doesn’t pose much of a threat.
“It does seem to be able to handle a little bit of salt,” JCU senior researcher Nathan Waltham said.
In a recent trip to the Torres Strait, he and his colleagues found the fish “in some hyper saline water holes,” Waltham said, “so there is some ability to resist exposure” to salt.
Read more at Discovery News
An artist named Marcantonio Raimondi created the engraving in 1505. But only recently did Ross Duffin, a music professor at Case Western Reserve University in Cleveland, identify the man in the engraving as Leonardo da Vinci, publishing the findings in the magazine Cleveland Art.
“This is serious and stands some chance of being right,” said Martin Kemp, an emeritus professor of art history at Oxford University who has written extensively about da Vinci, but who was not involved in the new research.
Is this Leonardo?
When the engraving entered the Cleveland Museum of Art’s collection in 1930, scholars thought the man in it was Orpheus, a musician in Greek mythology who was said to be so talented he could charm animals with his music. As such, the engraving was dubbed “Orpheus Charming the Animals.”
However, Duffin said he came to realize the man was unlikely to be Orpheus and more likely to be da Vinci taking on the role of Orpheus. During the Renaissance, “one thing that is extremely consistent is that Orpheus is shown as a clean-shaven youth, the young husband of the tragic Eurydice,” wrote Duffin in the article.
The man depicted in the engraving is in his “late middle age, with a beard and centrally partedhair with long curls,” wrote Duffin, adding that da Vinci would’ve been in his early 50s when Marcantonio Raimondi created the image.
Duffin compared the engraving with a portrait of da Vinci drawn by Francesco Melzi, “who joined the 54-year-old Leonardo’s household as an assistant in 1506 and eventually became his principal heir,” Duffin wrote.
“Melzi’s portrait shows a man with a beard and long curls, and the very slight bump in his nose and the ridge above the brow are an excellent match for the long-haired, bearded in the Marcantonio engraving.”
Most telling is the instrument the man in the engraving is playing. Duffin identified it as a lira da braccio, a bowed string instrument that da Vinci is known to have played.
In 1550, a few decades after da Vinci’s death, a historian named Giorgio Vasari wrote of da Vinci’s great musical skill. In 1494, “Leonardo was led in great repute to the Duke of Milan, who took much delight in the sound of the lira, so that he might play it,” Vasari wrote in his 1550 book “Le vite de’ più eccellenti pittori, scultori, e architettori” (translated).
“And Leonardo brought with him that instrument which he had made with his own hands, in great part of silver, in order that the harmony might be of greater volume and more sonorous in tone, with which he surpassed all the musicians who had come together there to play,” Vasari wrote. “Besides this, he was the best improviser in verse of his day.”
Problem with identification
If the engraving does indeed portray da Vinci, the question becomes how Marcantonio Raimondi met him.
“The problems are of time and place,” Kemp wrote in the email. “Marcantonio was working in Bologna at this early stage of his career, and there is no obvious way they would have met.”
At this stage, I would say that it is temptingly possible but unproven,” Kemp added.
Read more at Discovery News
But a new study reveals that the venerable tree is only 777 years old, which would make it a relative sapling compared to redwoods in forests further north, which date back as far as 1200 B.C. The tallest and oldest tree in Muir Woods sprouted about the time of the Spanish Inquisition.
Allyson Carroll, a dendrochronologist — that is, a tree-ring expert — at Humboldt State University, came up with the revised age by comparing a core sample from Tree 76 with a database of samples from other redwoods across California. The sample was taken by a team of scientists back in 2014, who climbed the trees in Muir Woods for the first time ever.
Carroll is working with the Save the Redwoods League, an environmental organization that is conducting the Redwoods and Climate Change Initiative, a project aimed at both gaining a better understanding of climate change from the historic trees and figuring out how to protect them from its effects.
Think of a tree’s rings like a fingerprint,” Carroll explained in an article on the league’s website. “There is a pattern of larger and smaller growth rings dependent on the climatic conditions experienced by that tree.”
Carroll also calculated the age of two fallen redwoods from Muir Woods. The Vortex Tree, which fell in 2011, was 693 years old, while ghe Solstice Tree, which fell the following year, was 536 years old, she concluded.
According to a National Parks Service history of the site, Muir Woods was given to the federal government in 1907 by its then-owner, William Kent, in order to prevent the forest from being seized by a local water company and logged to create a reservoir. While Kent staved off what would have been a devastating loss of trees, it may be that the forest itself is a survivor of some ancient catastrophe.
Read more at Discovery News
Archaeologists were working the site on the north Kimberley coast of Western Australia when they came across the unique gem below the surface, said Kat Szabo, an associate professor at the University of Wollongong.
“Natural pearls are very rare in nature and we certainly — despite many, many (oyster) shell middens being found in Australia — we’ve never found a natural pearl before,” Szabo, who specializes in studying shells at archaeological sites, said.
A midden is a prehistoric refuse pit.
“The location makes it particularly significant because the Kimberley coast of Australia is synonymous with pearling, and has been for the better part of the last century.”
The pink-and-gold-colored pearl is almost spherical, with a five-millimeter diameter. Due to its near-perfect round shape, the researchers used a micro CT scan to test its age and prove that it was naturally occurring rather than a farmed modern cultured pearl.
The oysters that produce pearls have been used in rainmaking ceremonies in indigenous cultures, and their shells have been found in the central desert more than 1,500 kilometers (930 miles) away.
Archaeologists have known about the rainmaking rituals but were not aware of how far back in history they had been practiced.
“Studying the pearl has led us to the study of the layer in which it’s found,” Szabo said.
Read more at Discovery News
A new analysis of Hubble Space Telescope images shows that at least two of the moons, Nix and Hydra, wobble constantly and unpredictably, the result of orbiting not just Pluto, but its cosmic companion, Charon.
“Their mutual motion creates a time-variable and distinctly asymmetric gravity field,” that in turn makes the outer moons’ orbits wobble, astronomers Mark Showalter, with the SETI Institute in Mountain View, Calif., and Douglas Hamilton with the University of Maryland, write in this week’s Nature.
Complicating the cosmic waltz are the odd, football shapes of the small moons. Scientists suspect sibling moons Kerberos and Styx are in similar situations.
The research is expected to flesh out details about the events that led to the formation of the solar system and provide insights about how similar systems form around other stars in the galaxy.
Scientists will get their first close-up look at Pluto and its entourage when NASA’s New Horizons spacecraft sails by next month.
From Discovery News
As of 10:40 a.m. CET (5:40 a.m. ET), the Large Hadron Collider (LHC) was running at record-breaking energies and collecting science data. Physicists now expect the particle collider to run non-stop for the next 3 years. We are in a new era of high-energy particle physics where, for the first time, we don’t exactly know what we’ll find.
“With the LHC back in the collision-production mode, we celebrate the end of two months of beam commissioning,” said CERN Director of Accelerators and Technology Frédérick Bordry in a press release. “It is a great accomplishment and a rewarding moment for all of the teams involved in the work performed during the long shutdown of the LHC, in the powering tests and in the beam commissioning process. All these people have dedicated so much of their time to making this happen.”
Today, LHC engineers and scientists announced they had “stable beams” in the LHC’s 27 kilometer (17 mile) long ring of supercooled electromagnets — meaning the protons that are injected into the experiment are suitable for the numerous detectors linked with the LHC can begin taking science data. Now that stability has been achieved, more protons will be pumped around the accelerator until the LHC has the ability to produce up to 1 billion particle collisions per second.
The prime mission of the LHC during Run 1 (that started in 2008) was to detect and characterize the “missing piece” of the Standard Model, the Higgs boson. This particle, which mediates the Higgs field that is thought to permeate the entire universe, endows all matter with mass. But to detect the Higgs, never before seen particle energies were required. Its historic discovery was announced in July 2012, resulting in the Nobel Prize for Physics being awarded to the physicists who first theorized the Higgs mechanism in the 1960′s.
Now, the power of the LHC has been ramped-up to 13 TeV, almost double the energy that produced the Higgs boson discovery.
“The first 3-year run of the LHC, which culminated with a major discovery in July 2012, was only the start of our journey. It is time for new physics!” said CERN Director General Rolf Heuer. “We have seen the first data beginning to flow. Let’s see what they will reveal to us about how our universe works.”
We are truly at the leading edge of science discovery where, over the coming 3 years, our view on the universe could completely change. Although physicists are pinning their hopes on the LHC to produce elusive dark matter particles, an answer to why there is more matter than antimatter in the universe and maybe even provide hints of supersymmetry, they also hope that something entirely unexpected pops out of the data. Should this happen, the data recorded by the LHC’s four main refurbished experiments — ALICE, ATLAS, CMS and LHCb — and 3 smaller experiments — TOTEM, LHCf and MoEDAL — could take decades to understand.
“The collisions we are seeing today indicate that the work we have done in the past two years to prepare and improve our detector has been successful and marks the beginning of a new era of exploration of the secrets of nature,” said CMS spokesperson Tiziano Camporesi. “We can hardly express our excitement within the collaboration: this is especially true for the youngest colleagues.”
Read more at Discovery News
Jun 2, 2015
In a paper published in the journal Icarus, the researchers use state-of-the-art computer models to simulate the dynamics of comet impacts on the lunar soil. The simulations suggest that such impacts can account for many of the features in the mysterious swirls.
"We think this makes a pretty strong case that the swirls represent remnants of cometary collisions," said Peter Schultz, a planetary geoscientist at Brown University. Schultz co-wrote the paper with his former graduate student, Megan Bruck Syal, who is now a researcher at the Lawrence Livermore National Laboratory.
Lunar swirls have been the source of debate for years. The twisting, swirling streaks of bright soil stretch, in some cases, for thousands of miles across the lunar surface. Most are found on the unseen far side of the Moon, but one famous swirl called Reiner Gamma can be seen by telescope on the southwestern corner of the Moon's near side. "It was my favorite object to look at when I was an amateur astronomer," Schultz said.
At first glance, the swirls do not appear to be related to large impact craters or any other topography. "They simply look as if someone had finger-painted the surface," Schultz said. "There has been an intense debate about what causes these features."
In the 1970s, scientists discovered that many of the swirls were associated with anomalies of the Moon's crustal magnetic field. That revelation led to one hypothesis for how the swirls may have formed. Rocks below the surface in those spots might contain remanent magnetism from early in the Moon's history, when its magnetic field was much stronger than it is now. It had been proposed that those strong, locally trapped magnetic fields deflect the onslaught of the solar wind, which was thought to slowly darken the Moon's surface. The swirls would remain brighter than the surrounding soil because of those magnetic shields.
But Schultz had a different idea for how the swirls may form -- one that has its roots in watching the lunar modules land on the Moon during the Apollo program.
"You could see that the whole area around the lunar modules was smooth and bright because of the gas from the engines scoured the surface," Schultz said. "That was part of what got me started thinking comet impacts could cause the swirls."
Comets carry their own gaseous atmosphere called a coma. Schultz thought that when small comets slam into the Moon's surface -- as they occasionally do -- the coma may scour away loose soil from the surface, not unlike the gas from the lunar modules. That scouring may produce the bright swirls.
Schultz first published a paper outlining the idea in the journal Nature in 1980. That paper focused on how the scouring of the delicate upper layer of lunar soils could produce brightness consistent with the swirls. The structure of the grains in the upper layer (termed the "fairy castle structure" because of the way grains stick together) scatters sun's rays, causing a dimmer and darker appearance. When this structure is stripped away, the remaining smoothed surface would be brighter than unaffected areas, especially when the sun's rays strike it at certain angles. For Reiner Gamma on the lunar nearside, those areas appear brightest during the crescent Moon just before sunrise.
As computer simulations of impact dynamics have gotten better, Schultz and Bruck-Syal decided it might be time to take a second look at whether comet impacts could produce that kind of scouring. Their new simulations showed that the impact of a comet coma plus its icy core would indeed have the effect of blowing away the smallest grains that sit atop the lunar soil. The simulations showed that the scoured area would stretch for perhaps thousands of kilometers from the impact point, consistent with the swirling streaks that extend across the Moon's surface. Eddies and vortices created by the gaseous impact would explain the swirls' twisty, sinuous appearance.
Read more at Science Daily
The hummingbird-sized specimen, described in the latest issue of the journal Nature Communications, reveals that early feathers were not just for flying, since the arrow-shaped feathers were not at all aerodynamically optimized.
Here, lead author Ismar de Souza Carvalho of the Universidade Federal do Rio de Janeiro describes the discovery:
They believe that the bird was a juvenile when it died of unknown causes.
The near-perfect fossil dates to the Early Cretaceous over 100 million years ago. It provides an unprecedented look at the tail feathers. Usually, these sorts of fragile appendages don’t preserve well, but they are in all of their 3D eye-catching drama in this fossil.
The scientists even found traces of color and pattern, suggesting that the bird would have been quite striking during its lifetime.
Since the feathers weren’t built for flying, the researchers write that they were likely “associated with sexual display, species recognition or visual communication” or all three.
Read more at Discovery News
Labelled “a sort of tea from China,” the box of dried leaves had remained unnoticed in the museum for more than 300 years.
Historians from Queen Mary University of London (QMUL) identified the sample as the oldest physical remnant of Britain’s favorite drink during research for an upcoming book called “Empire of Tea: The Asian Leaf that Conquered the World.”
“What makes the discovery so fascinating is that it captures the very moment at which tea was about to lay claim to a mass market in Britain,” QMUL researcher Richard Coulton, one of the authors of the book, said in a statement.
According to Coulton and colleagues Markman Ellis and Matthew Mauger, the other authors of the book, the tea was brought to Britain by James Cuninghame, a Scottish surgeon, trader and plant hunter, following one of his two trips to China in the late 17th and early 18th century.
Cuninghame joined an illicit private trading voyage to Amoy in Fujian province in 1697, which was a center for the early-modern tea trade.
“He arrived back in Britain in 1699 and very soon after set out again to China with the famous East India Company. He stayed for three years on the island of Chusan, where he found the tea plant growing wild and witnessed the local manufacturing of leaf tea,” Coulton said.
Today tea is a popular drink that crosses many cultures and traditions, but at that time it was considered an unusual, exotic and fashionable pleasure. Indeed, tea consumption in Britain became widespread only decades after Cuninghame imported the green leaves into the country around 1700.
“In the seventeenth century, the simple act of blending hot water with infused leaves was considered pretty extraordinary. It was priced as a luxury item and the best tea was ten times more expensive than the best coffee,” Coulton said.
It is known that in 1663, tea of the finest quality was sold at up to 60 shillings per pound, compared to the six shilling price for the best coffee.
Coulton and colleagues believe Cuninghame’s tea would have tasted much like an artisanal green tea today.
Read more at Discovery News
But the search might get a little easier, thanks to a recent discovery that a certain African plant seems to grow only atop the type of geological formation in which diamonds are found.
It all started when Florida International University geologist and research professor Stephen E. Haggerty, who also happens to be chief exploration officer of Youssef Diamond Mining Co., went on a field trip to northeastern Liberia in 2013. Haggerty was in search of a Kimberlite pipe, a carrot-like formation of rock that forms from magma and is pushed up from deep inside the Earth’s interior by volcanic eruptions. Though Kimberlite pipes don’t always contain diamonds, but they’re the primary source of the ones near the surface that are accessible to miners.
Haggerty found his Kimberlite pipe, but he also noticed something else. Rising out of the ground above the formation was a spiny, palm-like plant, Pandanus candelabrum, known to locals at a pamaya.
Further investigations on foot, by vehicle and from the air revealed that the odd-looking plant seemed to grow only in areas where diamond-bearing Kimberlite pipes are present, apparently because of the chemical composition of the soil above them.
“We don’t know if this plant can grow anywhere else where there aren’t kimberlite pipes present. It’s too early to tell,” Haggerty explained in a FIU press release. “The roots of the plant are typical of swampy areas, but for Liberia, it appears to be kimberlite-specific.”
The discovery, which Haggerty further detailed in an article for the journal Economic Geology, could make diamond prospecting a lot more efficient, by providing a conspicuous clue as to where diamonds might be found.
But the discovery has a few caveats. Only about 60 of the 6,000 pipes that have been discovered over the past century and a half have contained enough diamonds to make them worthwhile to mine, and only seven have turned out to contain so-called “super deposits” that make them highly lucrative, according to Bloomberg. And some of the last frontiers for diamond exploration are in the frozen Arctic regions of Russia and Canada, where the plants are not found.
From Discovery News
Jun 1, 2015
For the females to feel these vibrations, the courting couple must be standing on a suitable surface that can vibrate, like dry leaves, the researchers said in the new study.
Scientists had known that wolf spiders could make airborne sounds that are audible to humans. But this group of spiders doesn’t have typical ears, and it’s assumed that the critters can’t actually hear any airborne sounds, said Alexander Sweger, a doctoral student of biology at the University of Cincinnati, who presented the unpublished research at the Acoustical Society of America’s annual meeting in Pittsburgh on May 21.
“They’re quiet — nothing on the order of crickets,” Sweger told Live Science. “We think this airborne sound is primarily a byproduct. As far as we can tell, they may not deliberately be producing a sound.”
In fact, the “purring” wolf spider (Gladicosa gulosa) may help researchers learn how some animals use vibration, but not sound, to communicate, he said. Moreover, it’s possible that acoustic communication evolved from vibration, which is linked with sound, he said.
Sweger and his adviser, George Uetz, a professor of biological sciences at the University of Cincinnati, came across Gladicosa gulosa in the field one day. Intrigued, Sweger began reading literature on the species but found little research beyond the observational and anecdotal. So, he decided to study the spider, which has the unique ability to produce both vibrations and acoustic noises during courtship, he said.
The organ resembles a musical instrument: The wolf spider has two small, leglike appendages near its mouth called pedipalps. The lowest joint on the pedipalp has a rough surface (called a file) on one side and a scraper on the other. The spider can rub its pedipalps together so that the file and scraper cross each other, “and that creates the vibrations that then travel down the limb to the leaf,” Sweger said. Wolf spiders don’t spin webs, but are adept hunters with keen eyesight. Researchers have known about wolf spider vibrations since the 1970s, when they described their stridulatory organ, Sweger said.
“They’re courting on dead leaves,” he said. “And that leaf itself is what’s resulting in the airborne sound.”
In an experiment, Sweger and his colleagues recorded the vibration made by a male G. gulosa with an instrument that can digitize the vibration and convert it into an audible sound. They also used a microphone to record the spider during courtship, “so it’s essentially the airborne sound you would hear in the room,” he said.
Then, they played the airborne sounds to both males and females that were stationed on either granite or paper.
Read more at Discovery News
The discovery, reported in the journal Current Biology, marks the first time that living offspring from virgin births -- births where the mother did not mate with a male -- have been found in a normally sexually reproducing animal in nature.
Lead author Andrew Fields explained to Discovery News that “with fragmented habitat and low abundance,” it is likely that female smalltooth sawfish, known for their iconic tooth-studded rostrum or “saw,” are having trouble findings males. Lack of mating can then trigger the unusual births among certain adult females, he and his team suspect.
Fields, a researcher at the Stony Brook University’s School of Marine and Atmospheric Science, and his colleagues were conducting routine DNA fingerprinting of the sawfish (a type of ray related to sharks) in a Florida estuary when they determined that about 3 percent of those studied arose due to virgin birthing, a process technically known as parthenogenesis.
This phenomenon is thought to occur when an unfertilized egg absorbs a genetically identical sister cell. The resulting offspring have about half of the genetic diversity of their mothers and often die. In this case, however, the “parthogens” looked to be in perfect health, so the scientists just tagged and released them as part of an ongoing study that they are conducting on sawfish movements.
As for how those individuals might then reproduce later in life, Fields said, “They may give birth sexually or asexually.”
It is likely that virgin births are more common than previously thought among sharks and rays, both in captivity and in the wild. It is harder to detect and confirm the latter, given that DNA testing would be needed. Such births over the years, though, have surprised many aquarium staff members, who have found baby sharks suddenly appearing in tanks inhabited for lengthy periods by a lone female or multiple females and no males.
Senior author Demian Chapman, also from Stony Brook University, told Discovery News, “We know of parthenogenesis in blacktip, bonnethead, whitetip reef, whitespotted bamboo, and zebra sharks in captivity, so (there are) 5 species total.”
More species are expected to be added to that list. Some birds and reptiles have also undergone parthenogenesis in captivity.
For the smalltooth sawfish, the discovery is a dire warning about the species’ dwindling population. Fields said that it and other sawfish “are on the brink of extinction.”
He says that, for the smalltooth sawfish, “there is no accurate estimated population size, but it seems to be at 1–5 percent of historical levels based on the best evidence available. The primary threats are entanglement during fishing and habitat loss.”
Read more at Discovery News
Over 120,000 rare saiga antelopes — more than a third of the total global population — have been wiped out in a devastating blow that the United Nations Environment Program has called “catastrophic”.
UN experts have said the mass deaths are down to “a combination of biological and environmental factors.”
Scientists have struggled to put their finger on the exact nature of the disease that has felled entire herds, but say findings point towards an infectious disease caused by various bacteria.
Any infections have likely been exacerbated by recent rains that have made the antelopes — 90 percent of which live on the steppes of Central Asian Kazakhstan — less able to cope with diseases.
“Unseasonal wetness may have been something that lowered their immunity to infection but until we do more analysis we will not know anything for sure,” Steffen Zuther of the Altyn Dala Conservation Initiative said.
The rate of the deaths has staggered those who have studied the species — whose ancestors have inhabited the region since the ice age.
“A one hundred percent mortality for the herds affected is extraordinary,” said Richard Kock, a professor at the Royal Veterinary College in London who recently returned from Kazakhstan.
“We are dealing with creatures that have fairly low resilience.”
The sudden spate of deaths comes as a nasty shock as up until recently the saiga antelopes — which live for between six and 10 years and are known for their protruding noses — had been hailed as something of a conservation success.
Until mid-May, when the country’s Ministry of Agriculture began reporting the deaths, saiga numbers in Kazakhstan had rallied from an estimated 20,000 in 2003 to the more than 250,000.
In 1993, there were over a million saiga antelopes, mostly concentrated in the steppe land of Kazakhstan, neighbouring Russia and Mongolia.
The susceptibility of the population since then has raised extinction fears and the saiga is listed as critically endangered by the International Union for Conservation of Nature (IUCN).
- Decade to recover -
While herds that have not already been struck down are thought to be safe for the moment, Kazakhstan’s Prime Minister Karim Massimov set up a working group including international experts Thursday to establish reasons for the deaths and oversee disinfection of lands in the three regions where the saiga died.
“If there is one positive that has come from this it is that the government has become very open to international channels of cooperation now,” Kock from the Royal Veterinary College in London said.
Even then, however, scientists estimate that it will take a decade for the antelope numbers to recover from the recent deaths.
Read more at Discovery News
This finding could lead to better modeling and forecasting of disruptive solar storms in the future, the scientists added.
Solar eruptions, known as coronal mass ejections, are the hurricanes of space weather. These explosions can drive on the order of a billion tons of super-hot matter out from the sun.
When coronal mass ejections hit Earth, they can trigger major disturbances known as geomagnetic storms, which can in turn wreak massive havoc. For example, in 1989, a coronal mass ejection blacked out the entire Canadian province of Quebec within seconds, damaging transformers as far away as New Jersey, and nearly shutting down U.S. power grids from the mid-Atlantic through the Pacific Northwest.
To forecast the hazards that coronal mass ejections might pose to assets both on the ground and in space, researchers need to know where they are headed. However, much remains unknown about what guides their direction, and therefore whether they might hit Earth.
For instance, on Jan. 7, 2014, astronomers spotted a very fast coronal mass ejection headed toward Earth, one traveling more than 5.3 million mph (8.6 million km/h). Scientists expected it would trigger a strong geomagnetic storm, one that could spark radio navigation problems and set off alarms in power systems. However, the worst of the eruption missed Earth, and no geomagnetic storm followed.
To learn more about why this coronal mass ejection missed Earth, scientists collected data from 7 different space missions that saw the explosion. They modeled the evolution of the eruption from the sun, up to Earth, and as far as Mars, where it was detected by the Curiosity rover.
Instead of hitting Earth, the coronal mass ejection was slanted toward a zone below and behind Earth. The researchers suggest it got channeled this way by powerful magnetic fields originating from a region nearby on the sun.
"Very fast and possibly havoc-creating coronal mass ejections can erupt in a very different direction than indicated by the position of their source region on the sun,"study lead author Christian Möstl, a heliophysicist at the Austrian Academy of Sciences in Graz, told Space.com.
Potential applications of this research include better real-time predictions of space weather. "Forecasters should always look at the magnetic fields of the solar corona surrounding a big eruption to see how likely such a strongly channeled eruption is," Möstl said.
Read more at Discovery News
Take, for example, this stunning observation by the NASA/ESA Hubble Space Telescope. Astronomers have stitched together 20 years-worth of images of the spiral galaxy NGC 3862, which is located some 260 million light-years from Earth, and revealed a stunning relativistic collision inside the jet of material blasting from the galaxy’s central black hole.
This is one rare time that such a jet, stretching thousands of light-years from the center of a galaxy, has been observed using an optical telescope. Normally, these jets are only visible in X-ray and radio wavelengths, a factor that is currently a puzzle to astronomers.
The dynamics of black holes, particularly the mechanisms behind the powerful jets of hot plasma that are often observed emanating from active black holes, are largely a mystery. So when astronomers were able to create a time-lapse of NGC 3862′s central supermassive black hole, they were excited to not only see motion in those jets, but also bright knots in the jet material “rear-end” one another, causing a rapidly brightening “blob”.
Energetic jets aren’t exclusive to black holes, however. Young stars also exhibit powerful jets of material blasting from their poles and these jets often show a “knotty” structure, not so dissimilar to the knots observed in NGC 3862′s jet. So to understand how these jets are generated and how the material within them interact could help us understand an vast array of energetic phenomena throughout the universe.
The brightening blob in this black hole case was caused by a “shock collision” where a knot of material, moving at close to the speed of light, caught up with another slower-moving knot in that jet that was launched earlier. In the observations, the jets appear to be speeding away from the black hole many times the speed of light, but this “superluminal” motion is an optical illusion “due to the very fast real speed of the plasma, which is close to the universal maximum of the speed of light,” writes a Hubble press release. This is only the second time superluminal motion in an extragalactic jet has been observed.
“Something like this (the jet collision) has never been seen before in an extragalactic jet,” said Eileen Meyer of the Space Telescope Science Institute (STScI) in Baltimore, Md., and lead author of a new paper published in the May 28 issue of the journal Nature. “This will allow us a very rare opportunity to see how the kinetic energy of the collision is dissipated into radiation.”
“The collision of outward moving components in jets has long been known, but this is the first time we actually see it happening,” said co-author Markos Georganopoulos, University of Maryland in Baltimore County.
Read more at Discovery News
May 31, 2015
New observations with Alma have given astronomers their sharpest ever view of the famous double star Mira. The images clearly show the two stars in the system, Mira A and Mira B, but that's not all. For the first time ever at millimetre wavelengths, they reveal details on the surface of Mira A.
"Alma's vision is so sharp that we can begin to see details on the surface of the star. Part of the stellar surface is not just extremely bright, it also varies in brightness. This must be a giant flare, and we think it's related to a flare which X-ray telescopes observed some years ago," says Wouter Vlemmings, astronomer at Chalmers University of Technology, who led the team.
The team's results were recently published in the journal Astronomy & Astrophysics.
Red giants like Mira A are crucial components of our galaxy's ecosystem. As they near the end of their lives, they lose their outer layers in the form of uneven, smoky winds. These winds carry heavy elements that the stars have manufactured -- out into space where they can form new stars and planets. Most of the carbon, oxygen, and nitrogen in our bodies was formed in stars and redistributed by their winds.
Mira -- the name means "Wonderful" in Latin -- has been known for centuries as one of the most famous variable stars in the sky. At its brightest, it can be clearly seen with the naked eye, but when it's at its faintest a telescope is needed. The star, 420 light years away in the constellation Cetus, is in fact a binary system, made up of two stars of about the same mass as the sun: one is a dense, hot white dwarf and the other a fat, cool, red giant, orbiting each other at a distance about the same as Pluto's average distance from the Sun.
"Mira is a key system for understanding how stars like our sun reach the end of their lives, and what difference it makes for an elderly star to have a close companion," says Sofia Ramstedt, astronomer at Uppsala University and co-author on the paper.
The Sun, our closest star, shows activity powered by magnetic fields, and this activity, sometimes in the form of solar storms, drives the particles that make up the solar wind which in its turn can create auroras on Earth.
"Seeing a flare on Mira A suggests that magnetic fields also have a role to play for red giants' winds," says Wouter Vlemmings.
The new images give astronomers their sharpest ever view of Mira B, which is so close to its companion that material flows from one star to the other.
"This is our clearest view yet of gas from Mira A that is falling towards Mira B" says Eamon O'Gorman, astronomer at Chalmers and member of the team.
Read more at Science Daily