10/13 Wired: Science

Please add updates@feedmyinbox.com to your address book to make sure you receive these messages in the future. Wired: Science - Understanding the latest research and theories. Hunting Arctic Asteroid Impact With Hovercraft October 12, 2009 at 5:43 pm Two polar scientists hot on the trail of an arctic mystery have a new tool for exploration: a hovercraft, specially outfitted for week-long trips over the ice with scientific instruments and solar panels. Their quarry is a nearly 22,000 square-mile patch of disturbed Arctic sea floor that could be evidence of a massive asteroid strike. John Hall, a now-retired geoscientist, discovered the anomaly during his late-’60s graduate work aboard Fletcher’s Ice Island, a huge berg U.S. scientists inhabited for several decades. Since then, no scientific vessel has been back over the area to collect more data. The massive icebreakers that have crunched through the Arctic since the 1990s can’t reach the spot, said Yngve Kristofferson, a scientist and explorer at the University of Bergen in Norway. Kristofferson became intrigued with Hall’s data and in 2004, the two of them met in Bergen to talk Arctic science from eight in the morning to 10 in the evening. At the end of their time together, they came to a decision: They needed a hovercraft. Luckily, Hall is a partial heir to the fortune his grandfather made as head of the American Chicle Company, the trust that ran the American bubble gum game early in the 20th century, so he was able to buy the vehicle with private funds. A customized Griffon Hovercraft 2000TD, it is now going through the paces, hitting the Arctic from its home at Longyearbyen for the first time in 2008, and hoping to reach its full potential next spring. Hall delivered a speech detailing the craft’s capabilities and mission at Columbia University’s Lamont Doherty Earth Observatory on Oct. 6. “The neat thing with a hovercraft is that you drive with the same ease over 10 centimeter-thick ice as you do with five meter thick ice,” Kristofferson told Wired.com. Despite their futuristic reputation, hovercraft have been commercially available for decades. The concept is actually quite simple. A big engine or turbine pumps air into a rubber skirt that allows the vehicle to tread lightly on whatever it’s touching. The R/H Sabvabaa, for example, weighs six tons but exerts no more pressure on any patch of ice than a seagull standing on one leg would by standing on it. The rest of the power from the engine is devoted to propulsion, allowing the craft to skip along at speeds up to 50 miles per hour. For the strange terrain of the Arctic, it works perfectly, Hall and Kristofferson wrote in an article in the journal The Leading Edge in August. “The craft has proved to be useful for a variety of scientific tasks,” they wrote. “It appears more efficient than any other platform for ice-thickness measurements and oceanographic work.” Their hovercraft push comes as money has flooded into Arctic research. With Arctic ice melting, the nations adjacent to the ocean are rushing to stake their claims not just on the water, but on the oil and natural gas that lie under the sea floor, leading to calls to establish a National Park to protect the area. The most fascinating target for the hovercraft is the area of very thick ice closer to Ellesmere Island and northern Greenland. Not even nuclear-powered icebreakers have ventured into the region. It was just Hall’s good fortune to have been aboard the floating ice island doing research when it passed near this apparent sea floor anomaly. The duo, along with several other colleagues, described the discovery in a 2008 paper in the Norwegian Journal of Geology. “The upper couple hundred meters of sediment at the bottom of the Arctic Ocean is just like a carpet that is draped over the topography except for these areas where 150 meters are just blown away and the seabed is severely deformed,” Kristofferson said. To Kristofferson and Hall, the evidence suggests that a pressure wave caused by a pieces of a large asteroid crashing into the Arctic Ocean created these strange features. “Our working hypothesis is that the spectrum and scale of the observed disturbances are best explained as the effect of a shock wave generated by the impact of an extraterrestrial object,” they wrote. But the hypothesis remains just that without more data. The hovercraft works well, but with its on-board fuel, its range is limited to around 500 miles. For that reason, the scientists imagine they’ll use a larger vessel as a base of operations. “What we really want to do is go along with an icebreaker into the Arctic. You can greatly enhance the scientific output if you have a hovercraft. If you have more of them, even better,” Kristofferson said. “We can go out and do our own science and be away for many days. If the icebreaker gets stuck, we’re not stuck.” Still, both Hall and Kristofferson know they face an uphill battle to get other scientists to take both the hovercraft and asteroid impact ideas seriously. “The task is to figure out the real message in the data—the dream challenge for any scientist,” Kristofferson told the Lamont Doherty alumni magazine earlier this year. “So far, we have mostly met shaking heads, which just makes it more fun.” Image: Hall and Kristofferson. 1. The hovercraft. 2. Fletcher’s Ice Island Camp. Click through for more images of the hovercraft. Kinder, Gentler Spider Eats Veggies, Cares for Kids October 12, 2009 at 1:47 pm Each of the world’s 40,000 spider species survives by hunting and killing — except, that is, for Bagheera kiplingi, the world’s first vegetarian arachnid. Found in Central America, the order-defying jumping spider eats nutrient-rich structures called Beltian bodies, which are found on the tips of Acacia trees. Trees produce the bodies to feed ants that defend them, which is a textbook example of what’s called co-evolutionary mutalism, and one that B. kiplingi has evolved to exploit. In a paper published Monday in Current Biology, researchers describe the spider’s ant-evading habits and provide a molecular analysis of its body composition, proving that B. kiplingi is indeed what it eats: plants, with a few larval ants on the side. (After all, 400 million years of evolutionary habits die hard.) A few other spiders have been documented consuming nectar, but only as a snack. No other spider is so predominantly vegetarian. And that’s not all: It looks like B. kiplingi males help care for eggs and young — something entirely unprecedented in the spider world. The researchers are now studying whether there’s a link between B. kiplingi’s predilection for plants and parental concern. Maybe going veggie softened its heart. Image: Current Biology See Also: 1 Million Spiders Make Golden Silk for Rare Cloth 3D Imaging Technique Brings 50 Million-Year-Old Spider to Glorious Life Amazing Parasites Turn Ants Into Berries Citation: “Herbivory in a spider through exploitation of an ant-plant mutualism.” By Christopher J. Meehan, Eric J. Olson, Matthew W. Reudink, T. Kurt Kyser, and Robert L. Curry. Current Biology, Vol. 19, Issue 19, October 13, 2009. Brandon Keim’s Twitter stream and reportorial outtakes; Wired Science on Twitter. Brandon is currently working on a book about ecosystem and planetary tipping points. Photonic Six Pack Provides Better Quantum Communication October 12, 2009 at 12:10 pm To send a quantum message, it helps to have a photon six-pack. When bound together by a process called quantum entanglement, a set of six photons can withstand the hard knocks that ordinarily would erase quantum information, researchers have shown. Papers describing the new experiment appear in the Oct. 9 Physical Review Letters and the October Physical Review A. "This is an exciting landmark in experimental capabilities," comments physicist Aephraim Steinberg of the University of Toronto, who was not involved in the work. Creating the six-photon entanglement is an impressive technical achievement, he says. "This is the first demonstration of such large entangled states" with high quality. Quantum communication offers an absolutely secure way to send secret messages, such as encoded military secrets or financial transactions. But quantum information is fragile, quickly destroyed by even slight interactions with the environment. While a conventional bit of information can have only one value, 0 or 1, a quantum bit, or qubit, exists as a combination of 0 and 1 simultaneously. A qubit stays in this undecided state until something, whether a stray atom or a scientist trying to measure its properties, interacts with it, forcing it into a single state. This collapse of possibilities, known as quantum decoherence, can be detected farther down the line to catch eavesdroppers. But it can also keep qubits from reaching their destination intact. Fortunately, theorists have shown that some quantum-mechanical systems are immune to certain interactions. One of these resilient systems is a set of four or more photons that are intimately bound, or entangled, a property of quantum systems that links particles' fates even when they are separated by large distances. Delicate quantum bits find safety in numbers. The more photons are entangled, the more data can be encoded and transmitted reliably. Four photons can encode one robust qubit of information, and six photons can encode two, theorists have calculated. Now, a team of physicists led by Magnus Rådmark of Stockholm University has experimentally demonstrated a set of six entangled photons that can fly down flawed, noisy fiber-optic cables and emerge unscathed. "You'll get exactly the same state out as you sent in, even if the fiber is being stressed and the temperature is changing, and all of the environmental factors that would normally make it a no-go," Steinberg says. The key to preserving the state is to make sure all six photons are altered in exactly the same way. Temperature changes around the fiber-optic cable can alter the way it bends light, which in turn can rotate photons unpredictably. But if the photons travel in a close pack, they will all feel the same twists and bends. "If I take all six photons and rotate them in the same way, I will get exactly the same state I started with," says Mohamed Bourennane of Stockholm University, a coauthor on the papers. "It's like nothing has happened." As a bonus, this property means that the sender and receiver don't need to agree on which way is up. Changing the reference frame is just another rotation, the same kind of noise the photons ignored in the fiber. The photon sextet could also be useful in quantum computing, which could in principle manipulate entangled qubits to solve certain problems that are impossibly difficult for conventional computers.   This email was sent to carrizolaziale@gmail.com.  Create Your Account Don't want to receive this feed any longer? Unsubscribe here.

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