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586

EEE / Nanoparticles beat back atherosclerosis

« on: November 20, 2016, 06:26:42 PM »

Careening through the bloodstream, a single nanoparticle is dwarfed by red blood cells whizzing by that are 100 times larger. But when specially designed nanoparticles bump into an atherosclerotic plaque — a fatty clog narrowing a blood vessel — the tiny particles can play an outsized role. They can cling to the plaque and begin to break it down, clearing the path for those big blood cells to flow more easily and calming the angry inflammation in the vicinity.

By finding and busting apart plaques in the arteries, nanoparticles may offer a new, non-surgical way to reduce a patient’s risk for heart attack and stroke.

Nanoparticles measure less than 100 nanometers across — a thousandth the thickness of a dollar bill. Despite being tiny, they can be engineered to haul a mix of molecules — such as tags that make them stick to a plaque, drugs that block inflammation or dyes that let scientists track their movements. Over the last two decades, scientists have exploited these strategies to fight cancer, designing nanoparticles that deliver drugs (SN Online: 1/3/14) or dyes for imaging deep into the core of a tumor. The U.S. Food and Drug Administration has approved a few dozen cancer-focused nanomedicines.

Drugs, dyes and targeting molecules can be arranged on the perimeter or inside of a nanoparticle (illustration shows one that mimics HDL).
S. MARRACHE AND S. DHAR/PNAS 2013

Now researchers have begun engineering nanoparticles to target cardiovascular disease, which kills even more people each year than cancer. Nanosized compounds have been built that can sweep into clogged arteries to shrink the plaques that threaten to block blood flow. Some nanoparticles home in on the plaques by binding to immune cells in the area, some do so by mimicking natural cholesterol molecules and others search for collagen exposed in damaged vessel walls. Once at the location of a plaque, either the nanoparticles themselves or a piggybacked drug can do the cleanup work.

The aim of all these approaches is to prevent strokes and heart attacks in people with cardiovascular disease, either before surgery becomes necessary or after surgery to prevent a second event. Today, cardiovascular nanoparticles are still far from pharmacy shelves. Most have not reached safety testing in patients. But in mice, rats and pigs, nanodrugs have slowed the growth of the plaques that build up on vessel walls, and in some cases have been able to shrink or clear them.

“I think the effect we can have with these nanoparticles on cardiovascular disease is even more pronounced and direct than what we’ve seen in cancer,” says Prabhas Moghe, a biomedical engineer at Rutgers University in Piscataway, N.J.

Biological blockades
Every minute, more than a gallon of blood pumps through the human heart, pushing through miles of blood vessels to deliver oxygen and nutrients to organs and extremities. In a healthy person, the trip is as smooth as a drive on a freshly paved highway. But in the more than 10 percent of U.S. adults who have cardiovascular disease, the route might be more like a pothole-filled road squeezed by Jersey barriers.

Waxy globs, or plaques, of fat and cholesterol line the blood vessels, thickening and hardening the walls, impeding blood flow. As fat builds up inside the vessels, it also leaks into the vessel walls, swelling them and signaling the body to send immune cells to the area. The congregation of immune cells aggravates the blockage, the way emergency vehicles surrounding the site of a multi-car pileup further slow traffic on a highway.

“The inflammation and the accumulation of fat in the walls of the blood vessel sort of feed off each other and exacerbate each other,” Moghe says.

If the plaques grow large enough, or pieces chip off and travel to smaller vessels, they can block a vessel. If oxygen-filled blood can’t reach the brain or heart, a stroke or heart attack results.

The drugs most often prescribed to prevent or treat atherosclerosis — plaque buildup on the inner walls of the arteries — are statins (SN: 5/5/12, p. 30). This highly successful and effective class of drugs, available since 1987, slows the growth of the fatty plaques by lowering the amount of cholesterol circulating in the blood. But taking statins is akin to limiting the number of cars on a damaged road rather than repairing potholes, some argue. And the drugs can boost a person’s risk of diabetes and liver damage. In many cases, patients don’t begin taking statins until they already have severe atherosclerosis, and the drugs do little to reverse the buildup of plaques that already exist.

“Heart disease is still the number one killer in the U.S.,” says endocrinologist and biochemist Ira Tabas of Columbia University Medical Center. Drug-carrying nanoparticles that can shrink existing atherosclerotic plaques and eliminate the accompanying inflammation could change that, Tabas and others say.

587

EEE / Lidar maps vast network of Cambodia’s hidden cities

« on: November 20, 2016, 06:26:06 PM »

Thanks to modern laser technology, Southeast Asia’s Khmer Empire is rising from forest floors for the first time in centuries.

New findings show the remarkable extent to which Khmer people built cities and transformed landscapes from at least the fifth to the 15th century, and perhaps for several hundred years after that, says archaeologist Damian Evans of Cambodia’s Siem Reap Center. Laser mapping in 2015 of about 1,910 square kilometers of largely forested land in northern Cambodia indicates that gridded city streets and extensive canals emerged surprisingly early, by around A.D. 500, Evans reports June 13 in the Journal of Archaeological Science. Researchers have generally assumed that large-scale urban development began later at Greater Angkor, capital of the Khmer Empire from the ninth to 15th centuries (SN: 5/14/16, p. 22).

A helicopter carrying light detection and ranging equipment, lidar for short, flew sorties over seven Khmer sites in the vicinity of Greater Angkor. Lidar’s laser pulses gathered data on the contours of jungle- and vegetation-covered land. Lidar maps revealed city blocks, canals and other remnants of past settlements.

588

EEE / Moral dilemma could put brakes on driverless cars

« on: November 20, 2016, 06:25:36 PM »

Driverless cars are revved up to make getting from one place to another safer and less stressful. But clashing views over how such vehicles should be programmed to deal with emergencies may stall the transportation transformation, a new study finds.

People generally approve of the idea of automated vehicles designed to swerve into walls or otherwise sacrifice their passengers to save a greater number pedestrians, say psychologist Jean-François Bonnefon of the Toulouse School of Economics in France and his colleagues. But here’s the hitch: Those same people want to ride in cars that protect passengers at all costs, even if pedestrians end up dying, the researchers report in the June 24 Science.

“Autonomous cars can revolutionize transportation,” says cognitive scientist and study coauthor Iyad Rahwan of the University of California, Irvine and MIT. “But they pose a social and moral dilemma that may delay adoption of this technology.”

Such conflict puts makers of computerized cars in a tough spot, Bonnefon’s group warns. Given a choice between driverless cars programmed for the greater good or for self-protection, consumers will overwhelmingly choose the latter. Regulations to enforce the design of passenger-sacrificing cars would backfire, the scientists suspect, driving away potential buyers. If so, plans for easing traffic congestion, reducing pollution and eliminating many traffic accidents with driverless cars would be dashed.

589

EEE / Light-activated heart cells help guide robotic stingray

« on: November 20, 2016, 06:24:54 PM »

A new stingray bot about the size of a penny relies on light-sensitive heart cells to swim. Zaps with light force the bot’s fins to flutter, letting researchers drive it through a watery obstacle course, Kit Parker of Harvard University and colleagues report in the July 8 Science.

The new work “extends the state of the art — very much so,” says bioengineer Rashid Bashir of the University of Illinois at Urbana-Champaign. “It’s the next level of sophistication for swimming devices.”

For decades, the field of robotics has been dominated by bulky, rigid machines made mostly of metal or hard plastic. But in recent years, some researchers have turned toward softer, squishier materials, such as silicones and rubbery plastics (SN: 11/1/14, p.11). And a small group of scientists have taken it one step further: combining soft materials with living cells.

So far, there’s just a handful of papers on these hybrid machines, says Bashir, whose own lab recently reported the invention of tiny, muscle-wrapped bots that inch along like worms in response to light.

In 2012, Parker’s team built a robotic jellyfish out of silicone and heart muscle cells. Electrically stimulating the cells let the jellyfish push itself through water by squeezing its body into a bell shape and then relaxing.

But, Parker says, “the jellyfish just swam.” He and his colleagues couldn’t steer it around a tank. They can, however, steer the new stingray.

He explains the team’s strategy with a story about his daughter. When she was little, Parker would point his laser pointer at the sidewalk and she’d try to stomp on the dot. He could guide her down a path as she followed the light. “She got to be independent and I got to make sure she didn’t step out into traffic.”

Parker guides his stingray bot in a similar way.

Layered on top of the bot’s body — a gold skeleton sandwiched between layers of silicone — lies a serpentine pattern of cells. The pattern is made up of about 200,000 these cells, harvested from rat hearts and then genetically engineered to contract when hit with pulses of blue light.

590

EEE / SPIDER shrinks telescopes with far-out design

« on: November 20, 2016, 06:24:05 PM »

In the space business, weight and size are what run up the bills. So imagine the appeal of a telescope that’s a tenth to as little as a hundredth as heavy, bulky and power hungry as the conventional instruments that NASA and other government agencies now send into space. Especially alluring is the notion of marrying the time-tested technology called interferometry, used in traditional observatories, with the new industrial field of photonics and its almost unimaginably tiny optical circuits.

Say hello to SPIDER, or Segmented Planar Imaging Detector for Electro-optical Reconnaissance.

Some doubt it will ever work.

But its inventors believe that, once demonstrated at full-scale, SPIDER will replace standard telescopes and long-range cameras in settings where room is scarce, such as on planetary probes and reconnaissance satellites.

Researchers at the Lockheed Martin Advanced Technology Center in Palo Alto, Calif., with partners in a photonics lab at the University of California, Davis, have described work on SPIDER for several years at specialty conferences. In January, they revealed their progress with a splash to the public in a press release and polished video.

Somewhat like a visible-light version of a vast field of radio telescopes, but at a radically smaller scale, a SPIDER scope’s surface would sparkle with hundreds to thousands of lenses about the size found on point-and-shoot cameras. The instrument might be a foot or two across and only as thick as a flat-screen TV.

Transit system for light
SPIDER probably won’t be equivalent to a large instrument such as the Hubble Space Telescope, but it could be a smaller, lighter alternative to modest telescopes and long-range cameras. Experts tend to rank telescopes by their aperture — the size of the bucket that catches light or other such radiation. The wider the bucket’s mouth, the higher the resolution. Ordinarily, behind the bucket’s maw is an extensive framework for massive lenses, mirrors and heating or cooling systems. Hubble’s aperture spans 2.4 meters; its power-generating solar panels enlarge it to the size and weight of a winged city bus. Even a compact telescope with a saucer-sized lens might have more than a kilogram of equipment stretched behind its face for a third of a meter or so.

591

EEE / Supersmall device uses individual atoms to store data

« on: November 20, 2016, 06:22:46 PM »

These orderly patterns of dark blue dots indicate where individual chlorine atoms are missing from an otherwise regular grid of atoms. Scientists manipulated these vacancies to create a supersmall data storage device.

The locations of vacancies encode bits of information in the device, which Sander Otte of Delft University of Technology in the Netherlands and colleagues describe July 18 in Nature Nanotechnology. The team arranged and imaged the vacancies using a scanning tunneling microscope. The storage system, which can hold a kilobyte of data, must be cooled to a chilly −196° Celsius to work.

To demonstrate the technique, the researchers transcribed an excerpt from a famous 1959 lecture by physicist Richard Feynman, “There’s Plenty of Room at the Bottom,” which predicted the importance of nanotechnology. In each block, paired rows represent letters. Blocks marked with an “X” were unusable. The encoded 159 words of text  fill a region a ten-thousandth of a millimeter wide.

If scaled up, the researchers say, the technology could store the full contents of the U.S. Library of Congress in a cube a tenth of a millimeter on each side.

592

EEE / Activity trackers fall short in weight-loss trial

« on: November 20, 2016, 06:21:30 PM »

Carefully counting steps, stairs and sprints might backfire for some people. At the end of a two-year weight-loss trial, people who used activity monitors had lost less weight than people without the device. The results, described in the Sept. 20 JAMA, are the exact opposite of what researchers expected to find.

Going into the study, researchers thought that wearable technology would help people, particularly tech-savvy young adults, keep extra weight off. “It turns out that it actually worked against us,” says study coauthor John Jakicic, a weight-management researcher at the University of Pittsburgh.

Jakicic and colleagues followed 470 overweight or obese young adults, ages 18 to 35, over two years as they completed a weight-loss program that focused on healthful eating, exercise and support through meetings, phone calls and texts. During the first six months, participants lost fairly comparable amounts of weight.


J. HIRSHFELD; SOURCE: J.M. JAKICIC ET AL/JAMA 2016

Six months after starting a weight-loss program that encouraged healthy behavior, young adults had lost weight. But as the months went by, activity monitors didn't seem to help people maintain their weight loss, researchers found.

The real challenge, though, is in keeping extra weight off. And that’s why researchers turned to an exercise monitor. At the six-month mark, half the participants received an armband device that monitored their activity levels, providing readouts to both participants and researchers. But unexpectedly, by the end of the study, people without the device had maintained a better weight loss — 5.9 kilograms on average, or about 13 pounds. People with the device lost only 3.5 kilograms on average, or about 7.7 pounds.

Other factors, however, such as overall fitness, body fat and diet were similar for both groups at the study’s end. These factors “are just as, if not more, important than solely weight,” points out developmental psychologist Amanda Staiano of Louisiana State University’s Pennington Biomedical Research Center in Baton Rouge. It’s puzzling why only weight seemed to be affected by the technology.

“We’ve been scratching our heads,” Jakicic says of the finding. He and colleagues have a few possible explanations. Perhaps the device encourages people to lean too heavily on the technology and its emphasis on moving, and users let other aspects of weight loss slip. “Everyone is looking for a magic bullet,” he says, but weight loss is hard. Or, instead of getting motivated by a challenge, people trying to lose weight might be discouraged if their activity level readouts are low. What’s more, after a few months of using the gadget, people might become bored and stop using it as much. “Maybe these technologies lose their luster,” Jakicic says. “If you’re not wearing it, it won’t be helpful to you.”

A lack of engagement could help explain the results, says physical activity epidemiologist Lisa Cadmus-Bertramof the University of Wisconsin‒Madison. “Technology can be helpful, but we should absolutely expect that it could backfire if the device isn't ideal,” she says. On days when people wore the armband monitor, they typically wore it for only about four hours — far less than people usually wear a wristband Fitbit, she adds.

The good news is that a small number of people with the technology kept off more weight than the average of people with the device. Jakicic and colleagues are analyzing why those people seemed to benefit while others did not.

A strength of the new study is its focus on young adults, about a quarter of whom were not white. Young people, and particularly young minorities, are “in need of creative, effective strategies to combat their historically high rate of obesity,” says Staiano, who is also a spokesperson for the Obesity Society. Because young adults spend much of their days using technology, scientists shouldn’t give up attempts to figure out how to enlist devices to help manage weight, she says. Today’s gadgets, which look like jewelry on the wrist and can track not just activity but also diet, sleep and mood, may still hold promise. 

593

EEE / Tenio Popmintchev fits X-ray laser on a tabletop

« on: November 20, 2016, 06:20:57 PM »

xperimental physics is not for the fainthearted. One tiny error — or a concatenation of many — can keep a complicated experiment from working smoothly. Fortunately, Tenio Popmintchev has the tenacity for it.

Popmintchev, a laser physicist at the JILA institute at the University of Colorado Boulder, thinks nothing of running an experiment for 72 hours straight, or spending years tinkering with a finicky set of high-powered lasers, or shipping the entire setup to Vienna to re-create the experiments with collaborators there. A commitment to detail drives Popmintchev’s rising career, says his adviser and mentor Henry Kapteyn. “Tenio is not intimidated by what might go wrong in an experiment, and is very good at identifying and investigating the unknowns that might be holding an experiment back,” Kapteyn says.

At age 39, Popmintchev has already played a key role in inventing the first tabletop X-ray laser, which uses short pulses of light to illuminate the nature of matter. Its bright beams promise to probe everything from the movements of electrons and atoms within DNA to the folding of proteins in extraordinary detail. It would be relatively cheap and multipurpose, a Swiss army knife made of light that many researchers could use. “The same kind of revolution that happened with lasers in the 1960s is happening now in X-ray science,” Popmintchev says.

He began his drive toward physics early, while growing up in the town of Kazanlak in central Bulgaria. He was planning to study mathematics until a high school teacher cannily told him that physicists were the best mathematicians of all. And with that, the teacher had a fresh recruit for the national physics Olympiad team.

The same kind of revolution that happened with lasers in the 1960s is happening now in X-ray science.
— Tenio Popmintchev

Popmintchev went on to take honorable mention in an International Physics Olympiad in ninth grade and a bronze medal in 11th grade. He still speaks about that teacher fondly. “We used to solve problems the whole day long,” he says. “It was a lot of fun.”

In college, he started to explore the world of lasers with a physicist who had trained under the same teacher. They worked on infrared lasers for cosmetic surgery, and Popmintchev found his niche in coaxing the best out of experimental equipment. For his Ph.D. work, Popmintchev moved to one of the world’s top labs for studying ultrafast lasers, established in Boulder by Kapteyn and his collaborator and wife, Margaret Murnane.

Like a strobe light revealing the motion of dancers under a disco ball, ultrafast lasers can “freeze” atoms and molecules by illuminating them with every flash. Kapteyn and Murnane’s group uses lasers that pulse on the order of attoseconds, or billionths of a billionth of a second. “One attosecond is to a second as a second is to the age of the universe,” Popmintchev says. That superfast stop-motion means that scientists can glimpse atoms and molecules interacting with one another.

Popmintchev’s research aimed to push these frontiers past the usual wavelengths and into the higher energies of X-rays. Unlike infrared or ultraviolet light, X-rays can penetrate objects to reveal internal structure, like dental X-rays highlighting cavities. But making enough X-rays, with enough power, can require enormous, billion-dollar machines that accelerate electrons to high speeds.

Popmintchev wanted to find a way to make X-ray lasers accessible to more scientists. He turned to a method called high-harmonic generation, which was discovered in 1987 when researchers noticed that under certain conditions their lasers efficiently generated shorter wavelengths of light. The technique had been used mainly with ultraviolet lasers, but Popmintchev and colleagues realized that infrared lasers could be coaxed to produce X-ray pulses if they were sent beaming through pressurized gas.

So he built a cylinder that could fit in the palm of a hand and contains helium gas at 50 times atmospheric pressure. When laser light hits the high-pressure gas, it strips electrons off the helium. Each electron accelerates away from and then back toward its charged helium atom. When the electron crashes back into the helium, it releases extra energy gained from this acceleration as higher-energy X-rays. By tweaking the pressure of the gas and the intensity of the laser, Popmintchev could get the X-ray emissions to move in phase with one another, producing a coherent beam that his team could control with exquisite precision.

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EEE / Wi-Fi can help house distinguish between members

« on: November 20, 2016, 06:20:11 PM »

In smart homes of the future, computers may identify inhabitants and cater to their needs using a tool already at hand: Wi-Fi. Human bodies partially block the radio waves that carry the wireless signal between router and computer. Differences in shape, size and even gait among household members yield different patterns in the received Wi-Fi signals. A computer can analyze the signals to distinguish dad from mom, according to a report posted online August 11 at arXiv.org.

Scientists built an algorithm that was nearly 95 percent accurate when attempting to discern two adults walking between a wireless router and a computer. For six people, accuracy fell to about 89 percent. Scientists tested the setup on men and women of various sizes, but it should work with children as well, says study coauthor Bin Guo of Northwestern Polytechnical University in Xi’an, China.

In a home rigged with Wi-Fi and a receiver, the system could eventually identify family members and tailor heating and lighting to their preferences — maybe even cue up a favorite playlist.

595

EEE / New technique shows cells’ molecules in color

« on: November 20, 2016, 06:19:33 PM »

Electron microscopy is finally getting its Kodachrome moment.

The high-powered scopes can now produce images that simultaneously highlight different molecules in different colors, scientists report online November 3 in Cell Chemical Biology. That’s helpful for researchers hoping to visualize the complex structures of cells or tissues — such as connections between brain cells, shown here.

Electron microscopes build black-and-white images by shooting beams of electrons at samples. Previously, scientists could add color by overlaying lower-resolution images from light microscopes. The new technique adds pizzazz without sacrificing image quality. It involves sequentially layering different metal ions on top of the sample. Each ion selectively latches onto a different target molecule. The electron beam interacts differently with each ion, yielding signature wave shapes that can be converted into colors. The researchers used the coloring technique to show that two brain cells called astrocytes (the edge of one shown in green, the other in red) could link up to the same message-sending junction

596

EEE / XPRIZE launched new kind of space race, book recounts

« on: November 20, 2016, 06:18:48 PM »

On the 47th anniversary of Sputnik’s launch, former Navy pilot Brian Binnie flew a rocket-powered ship past the brink of outer space.

Named SpaceShipOne, the ship cruised up 112 kilometers, then plunged back to Earth, wings flared like a shuttlecock to slow its descent. SpaceShipOne’s October 4, 2004, flight, the second in two weeks, earned its makers fame and the Ansari XPRIZE.

The $10 million prize, created in 1996, aimed to spawn a fantastical new kind of tourism. One day, perhaps, ordinary people could book a ride on a rocket and gaze down on Earth from the blackness of space.

It was a prize to ignite the private space industry and to “bring about change in the stagnant aerospace world,” said XPRIZE founder Peter Diamandis. To win, contestants had to build a fully reusable manned spacecraft — something not even NASA has achieved (though the space shuttle came close).

In How to Make a Spaceship, journalist Julian Guthrie follows a handful of teams from around the world on the race to win the prize. She givesreaders a front-row seat to a rocket launch in Romania, a crash landing in Texas and spaceship building in California’s Mojave Desert.

Guthrie introduces the people behind the tech stuff, too. They’re engineers, pilots, airplane designers and more, and they’re so fired up about getting to space that they tap savings accounts, pull all-nighters and strap themselves into carbon fiber cockpits for test flights. These characters give Guthrie’s story lift, offering examples of inventiveness and drive as inspiring as the idea of spaceflight itself.

But frustration ensues, felt most keenly by Diamandis. The real challenge seems to be money. Diamandis, a doctor, entrepreneur and space aficionado, spent years securing the prize’s funding, knocking on the doors of nearly every famous billionaire around, including Richard Branson, Jeff Bezos and Elon Musk. (Eventually, the Ansari family, which earned its fortune in telecommunications, stepped in to sponsor the prize.)

But today the future of private spaceflight remains uncertain. SpaceShipOne now hangs in a museum, and SpaceShipTwo (known as VSS Enterprise) tore apart during a 2014 test flight. And despite successes, in September, a rocket from Musk’s aerospace company, SpaceX, burst into flames during a prelaunch test.

A second version of SpaceShipTwo, VSS Unity, may begin test flights this fall. Owned by Virgin Galactic, VSS Unity could be the first to offer spaceflights to paying customers. Making a spaceship is a dangerous business to be sure, but as Guthrie so vividly shows, some people will risk anything to reach the stars.

597

EEE / CT scans show first X-rayed mummy in new light

« on: November 20, 2016, 06:18:25 PM »

X-rays were the iPhone 7 of the 1890s. Months after X-rays were discovered in late 1895, German physicist Walter Koenig put the latest in tech gadgetry to the test by scanning 14 objects, including the mummified remains of an ancient Egyptian child. Koenig’s image of the child’s knees represented the first radiographic investigation of a mummy.

At the time, details on the mummy itself were scant. Originally collected by explorer-naturalist Eduard Rueppell in 1817, the specimen lacked any sort of decoration that might link it to a particular dynasty or time period. Koenig’s X-ray image of the mummy served less to fill in any of those blanks and more to demonstrate the technology’s potential. Since then, radiographic images have revealed hidden artifacts, elucidated embalming techniques and even pinpointed health issues and diseases in mummies.

The inverted appearance of the mummy’s knees in Koenig’s original X-ray probably happened when Koenig transferred the negative image into a positive.
© GERMAN RÖNTGEN MUSEUM

Now, biological anthropologist and Egyptologist Stephanie Zesch of the Reiss Engelhorn Museum in Mannheim, Germany, and colleagues have examined the mummy with modern imaging techniques. CT scans show that the child was a boy. His teeth suggest that he was 4 to 5 years old when he died. Radiocarbon dating places him in the Ptolemaic period, between 378 and 235 B.C., the researchers report online July 22 in the European Journal of Radiology Open.

The team also diagnosed a slew of health conditions: a common chest wall deformity called pectus excavatum, or sunken chest; bone density marks called Harris lines in his leg bones that indicate physiological stress; and an enlarged liver. The team attributes the distended liver to a parasitic infection like schistosomiasis, which is common in Egypt and sometimes lethal. Without any obvious signs of trauma, however, “it’s impossible to determine cause of death,” Zesch says.

598

EEE / How to read a book without opening it

« on: November 20, 2016, 06:17:52 PM »

Book lovers: Scientists have devised a way to read without cracking a volume’s spine or risking paper cuts (and no, we’re not talking about e-books). The new method uses terahertz radiation — light with wavelengths that are between microwave and infrared waves — to view the text of a closed book. The technique is not meant for your average bookworm, but for reading rare books that are too fragile to open.

Barmak Heshmat of MIT and colleagues started small, with a nine-page book of thick paper that had one letter inked on each page. By hitting the book with terahertz radiation and looking at the reflected waves, the scientists could read the letters within.

599

EEE / Europa spouting off again

« on: November 20, 2016, 06:11:51 PM »

Jupiter’s moon Europa might once again be venting water into space, further supporting the idea that an ocean hides beneath its thick shell of ice, researchers reported September 26 at a news conference.

Plumes erupting from the moon’s surface, silhouetted against background light from Jupiter, appear in several images taken by the Hubble Space Telescope in early 2014. The geysers — presumably of water vapor or ice particles — showed up in the same location as an eruption captured by Hubble in 2012 (SN: 1/25/14, p. 6). The eruptions also appear to be intermittent, appearing in only three out of 10 images. Material hovering over the moon’s southern hemisphere and absorbing ultraviolet light coming from Jupiter made the plumes visible.

“The plumes are a sign that we may be able to explore the ocean without having to drill through unknown miles of ice,” said William Sparks, an astronomer at the Space Telescope Science Institute in Baltimore. “We presume it to be water or ice particles because that’s what Europa is made of and those molecules do absorb at the wavelengths we observed,” he said. Future spacecraft could plow through the plumes and sample the water to better understand its chemistry and look for by-products of life.

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EEE / Rosetta spacecraft ends mission

« on: November 20, 2016, 06:10:31 PM »

Rosetta is no more. On September 30, the orbiter touched down on the surface of comet 67P/Churyumov–Gerasimenko and immediately shut down, bringing an end to the mission.

The landing site has been dubbed Sais, the ancient Egyptian town believed to be the original home of the Rosetta stone, after which the mission is named.

Confirmation came from a planned loss of radio signal from the spacecraft. Onboard computers were programmed to shut down when Rosetta hit the comet. The spacecraft approached the comet at just a few kilometers per hour, but the probe wasn’t designed for landings and was probably damaged.

Mission scientists will continue to keep busy analyzing all the data sent back before touchdown.