3-D view of Greenland Ice Sheet opens window on ice history

This is a cross-section of the age of the Greenland Ice Sheet. Layers determined to be from the Holocene period, formed during the past 11,700 years, are shown in green. Layers accumulated during the last ice age, from 11,700 to 115,000 years ago, are shown in blue. Layers from the Eemian period, more than 115,000 years old, are shown in red. Regions of unknown age are gray

Scientists using ice-penetrating radar data collected by NASA's Operation IceBridge and earlier airborne campaigns have built the first comprehensive map of layers deep inside the Greenland Ice Sheet, opening a window on past climate conditions and the ice sheet's potentially perilous future.

This new map allows scientists to determine the age of large swaths of the second largest mass of ice on Earth, an area containing enough water to raise ocean levels by about 20 feet.
"This new, huge data volume records how the ice sheet evolved and how it's flowing today," said Joe MacGregor, the study's lead author, a glaciologist at The University of Texas at Austin Institute for Geophysics (UTIG), a unit of the Jackson School of Geosciences.
Greenland's ice sheet has been losing mass during the past two decades, a phenomenon accelerated by warming temperatures. Scientists are studying ice from different climate periods in the past to better understand how the ice sheet might respond in the future.
Ice cores offer one way of studying the distant past. These cylinders of ice drilled from the ice sheet hold evidence of past snow accumulation and temperature and contain impurities such as dust and volcanic ash compacted over hundreds of thousands of years. These layers are visible in ice cores and can be detected with ice-penetrating radar.
Ice-penetrating radar works by sending radar signals into the ice and recording the strength and return time of reflected signals. From those signals, scientists can detect the ice surface, sub-ice bedrock and layers within the ice.
New techniques used in this study allowed scientists to efficiently pick out these layers in radar data. Prior studies had mapped internal layers, but not at the scale made possible by these newer, faster methods.
Another major factor in this study was the scope of Operation IceBridge's measurements across Greenland, which included flights that covered distances of tens of thousands of kilometers across the ice sheet.
"IceBridge surveyed previously unexplored parts of the Greenland Ice Sheet and did it using state-of-the-art CReSIS radars," said study co-author Mark Fahnestock, an IceBridge science team member and glaciologist from the Geophysical Institute at the University of Alaska Fairbanks (UAF-GI).
CReSIS is the Center for Remote Sensing of Ice Sheets, a National Science Foundation science and technology center headquartered at the University of Kansas in Lawrence, Kansas.
IceBridge's flight lines often intersect ice core sites where other scientists have analyzed the ice's chemical composition to map and date layers in the ice. These core data provide a reference for radar measurements and provide a way to calculate how much ice from a given climate period exists across the ice sheet, something known as an age volume. Scientists are interested in knowing more about ice from the Eemian period, a time from 115,000 to 130,000 years ago that was about as warm as today. This new age volume provides the first data-driven estimate of where Eemian ice may remain.
Comparing this age volume to simple computer models helped the study's team better understand the ice sheet's history. Differences in the mapped and modeled age volumes point to past changes in ice flow or processes such as melting at the ice sheet's base. This information will be helpful for evaluating the more sophisticated ice sheet models that are crucial for projecting Greenland's future contribution to sea-level rise.
"Prior to this study, a good ice-sheet model was one that got its present thickness and surface speed right. Now, they'll also be able to work on getting its history right, which is important because ice sheets have very long memories," said MacGregor.

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Story Source:
The above story is based on materials provided by University of Texas at Austin. Note: Materials may be edited for content and length.

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Journal Reference:

1. Joseph A. MacGregor, Mark A. Fahnestock, Ginny A. Catania, John D. Paden, S. Prasad Gogineni, S. Keith Young, Susan C. Rybarski, Alexandria N. Mabrey, Benjamin M. Wagman, Mathieu Morlighem. Radiostratigraphy and age structure of the Greenland Ice Sheet. Journal of Geophysical Research: Earth Surface, 2015; DOI: 10.1002/2014JF003215

Huge 3-D displays without 3-D glasses

Billboards of the future could show astonishing 3D effects, thanks to a new technology developed in Austria

A new invention opens the door to a new generation of outdoor displays. Different pictures can be seen at different angles, creating 3D effects without the need for 3D glasses.

Public screenings have become an important part of major sports events. In the future, we will be able to enjoy them in 3D, thanks to a new invention from Austrian scientists. A sophisticated laser system sends laser beams into different directions. Therefore, different pictures are visible from different angles. The angular resolution is so fine that the left eye is presented a different picture than the right one, creating a 3D effect.
In 2013, the young start-up company TriLite Technologies had the idea to develop this new kind of display, which sends beams of light directly to the viewers' eyes. The highly interdisciplinary project was carried out together with the Vienna University of Technology.
Together, TriLite and TU Vienna have created the first prototype. Currently it only has a modest resolution of five pixels by three, but it clearly shows that the system works. "We are creating a second prototype, which will display colour pictures with a higher resolution. But the crucial point is that the individual laser pixels work. Scaling it up to a display with many pixels is not a problem," says Jörg Reitterer (TriLite Technologies and PhD-student in the team of Professor Ulrich Schmid at the Vienna University of Technology).
Every single 3D-Pixel (also called "Trixel") consists of lasers and a moveable mirror. "The mirror directs the laser beams across the field of vision, from left to right. During that movement the laser intensity is modulated so that different laser flashes are sent into different directions," says Ulrich Schmid. To experience the 3D effect, the viewer must be positioned in a certain distance range from the screen. If the distance is too large, both eyes receive the same image and only a normal 2D picture can be seen. The range in which the 3D effect can be experienced can be tuned according to the local requirements.
Hundreds of Images at Once
3D movies in the cinema only show two different pictures -- one for each eye. The newly developed display, however, can present hundreds of pictures. Walking by the display, one can get a view of the displayed object from different sides, just like passing a real object. For this, however, a new video format is required, which has already been developed by the researchers. "Today's 3D cinema movies can be converted into our 3D format, but we expect that new footage will be created especially for our displays -- perhaps with a much larger number of cameras," says Franz Fiedler, CTO of TriLite Technologies.
Compared to a movie screen, the display is very vivid. Therefore it can be used outdoors, even in bright sunlight. This is not only interesting for 3D-presentations but also for targeted advertisements. Electronic Billboards could display different ads, seen from different angles. "Maybe someone wants to appeal specifically to the customers leaving the shop across the street, and a different ad is shown to the people waiting at the bus stop," says Ferdinand Saint-Julien, CEO of TriLite Technologies. Technologically, this would not be a problem.
Entering the market
"We are very happy that the project was so successful in such a short period of time," says Ulrich Schmid. It took only three years to get from the first designs to a working prototype. The technology has now been patented and presented in several scientific publications. The second prototype should be finished by the middle of the year, the commercial launch is scheduled for 2016.

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Story Source:
The above story is based on materials provided by Vienna University of Technology. Note: Materials may be edited for content and length.

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Journal Reference:

1. Jörg Reitterer, Franz Fidler, Gerhard Schmid, Thomas Riel, Christian Hambeck, Ferdinand Saint Julien-Wallsee, Walter Leeb, Ulrich Schmid. Design and evaluation of a large-scale autostereoscopic multi-view laser display for outdoor applications. Optics Express, 2014; 22 (22): 27063 DOI: 10.1364/OE.22.027063

Wormhole Time Travel 'Possible' (If You're a Photon) | sci-english.blogspot.com

Time travel? | sci-english.blogspot.com

The idea of traversable wormholes has been science fiction fodder since Einstein first theorized their existence with the formulation of his general theory of relativity, but do wormholes even exist in nature? Actually, we have no idea if they exist or not, but if they do, theoretical physicists have proposed that they could act as portals into the future and the past or connect two distant regions of space.

But before you grab your Grays Sports Almanac and get ready for some temporal mischief, there’s one huge caveat to this idea — only photons may travel… and even photons may be too much of a stretch for the hypothetical shortcut through spacetime.

In a paper published to the arXiv preprint service (and submitted to the journal Physical Review D), theoretical physicist Luke Butcher of the University of Cambridge has revisited wormhole theory and potentially found a way to bridge these notoriously unstable entities.
In the late 1980s, physicist Kip Thorne, of the California Institute of Technology (Caltech), theorized that to make a wormhole ‘traversable’ — as in to actually make these spacetime shortcuts stable enough to travel through — some form of negative energy would be required. In the quantum world, this negative energy could come in the form of Casimir energy.
It is well known that if two perfectly smooth plates are held very close together in a vacuum, quantum effects between the plates will have a net repulsive (or attractive, depending on the plate configuration) effect between the two. This is caused by waves of energy being too large to fit between the plates, causing a net negative energy between the plates when compared with the surrounding “normal” space.
As realized by Thorne and his Caltech team, this Casimir energy could be applied to the neck of a wormhole, potentially holding it open long enough for something to pass through.

Alas, we are talking about quantum-sized wormhole throats, meaning Marty McFly’s speeding DeLorean will be left revving in the 1985 parking lot, unable to squeeze through. But even if some quantum-sized traveler could pass through the wormhole’s neck, the wormhole would still likely collapse very quickly.
On reevaluating this scenario, Butcher has identified some more stable wormhole configurations and, in certain situations, the wormhole collapse could be prevented for an “arbitrarily long time.” But for this to happen, the wormhole needs to be very long and have a very narrow throat. In this case it seems possible that photons could traverse the wormhole.
“(T)he negative Casimir energy does allow the wormhole to collapse extremely slowly, its lifetime growing without bound as the throat-length is increased,” writes Butcher. “We find that the throat closes slowly enough that its central region can be safely traversed by a pulse of light.”
Butcher admits that although it’s not clear from his calculations whether the light pulse will be able to complete its journey from one end to the other, there is a tantalizing possibility for sending signals faster than the speed of light or even back in time.

“These results tentatively suggest that a macroscopic traversable wormhole might be sustained by its own Casimir energy, providing a mechanism for faster-than-light communication and closed causal curves.”
For the moment, this work is highly theoretical, but, as pointed out by Matt Visser of Victoria University of Wellington, New Zealand, in New Scientist on Tuesday, this research could renew interest in the study of wormholes and their potential spacetime-bridging capabilities.
So if we were to look for physical evidence of wormholes, could this research help us? Could we perhaps look out for be some kind of unique polarization of light that has traveled from another part of the Universe or some other time, appearing randomly in our local volume of spacetime? For answers to these questions, and as to whether this may spawn some kind of faster-then-light communications technology, we’ll likely have to wait until the theoretical physicists have crunched more numbers.

'4D Printing' Makes Shape-Shifting Structures | sci-english.blogspot.com

This grid was made by 4D printing. These images show how the grid could form a convex or concave surface | sci-english.blogspot.com

 Using a new technique known as 4D printing, researchers can print out dynamic 3D structures capable of changing their shapes over time.

Such 4D-printed items could one day be used in everything from medical implants to home appliances, scientists added.

Today's 3D printing creates items from a wide variety of materials — plastic, ceramic, glass, metal, and even more unusual ingredients such as chocolate and living cells. The machines work by setting down layers of material just like ordinary printers lay down ink, except 3D printers can also deposit flat layers on top of each other to build 3D objects.

 "Today, this technology can be found not just in industry, but [also] in households for less than $1,000," said lead study author Dan Raviv, a mathematician at MIT. "Knowing you can print almost anything, not just 2D paper, opens a window to unlimited opportunities, where toys, household appliances and tools can be ordered online and manufactured in our living rooms."

Now, in a further step, Raviv and his colleagues are developing 4D printing, which involves 3D printing items that are designed to change shape after they are printed. [The 10 Weirdest Things Created By 3D Printing]

"The most exciting part is the numerous applications that can emerge from this work," Raviv told Live Science. "This is not just a cool project or an interesting solution, but something that can change the lives of many."

In a report published online today (Dec. 18) in the journal Scientific Reports, the researchers explain how they printed 3D structures using two materials with different properties. One material was a stiff plastic, and stayed rigid, while the other was water absorbent, and could double in volume when submerged in water. The precise formula of this water-absorbent material, developed by 3D-printing company Stratasys in Eden Prairie, Minnesota, remains a secret.

The researchers printed up a square grid, measuring about 15 inches (38 centimeters) on each side. When they placed the grid in water, they found that the water-absorbent material could act like joints that stretch and fold, producing a broad range of shapes with complex geometries. For example, the researchers created a 3D-printed shape that resembled the initials "MIT" that could transform into another shape resembling the initials "SAL."

"In the future, we imagine a wide range of applications," Raviv said. These could include appliances that can adapt to heat and improve functionality or comfort, childcare products that can react to humidity or temperature, and clothing and footwear that will perform better by sensing the environment, he said.

In addition, 4D-printed objects could lead to novel medical implants. "Today, researchers are printing biocompatible parts to be implanted in our body," Raviv said. "We can now generate structures that will change shape and functionality without external intervention."

One key health-care application might be cardiac stents, tubes placed inside the heart to aid healing. "We want to print parts that can survive a lifetime inside the body if necessary," Raviv said.

The researchers now want to create both larger and smaller 4D-printed objects. "Currently, we've made items a few centimeters in size," Raviv said. "For things that go inside the body, we want to go 10 to 100 times smaller. For home appliances, we want to go 10 times larger."

Raviv cautioned that a great deal of research is needed to improve the materials used in 4D printing. For instance, although the 4D-printed objects the researchers developed can withstand a few cycles of wetting and drying, after several dozen cycles of folding and unfolding, the materials lose their ability to change shape. The scientists said they would also like to develop materials that respond to factors other than water, such as heat and light.

Why String Theory Still Offers Hope We Can Unify Physics | sci-english.blogspot.com

In October 1984 I arrived at Oxford University, trailing a large steamer trunk containing a couple of changes of clothing and about five dozen textbooks. I had a freshly minted bachelor’s degree in physics from Harvard, and I was raring to launch into graduate study. But within a couple of weeks, the more advanced students had sucked the wind from my sails. Change fields now while you still can, many said. There’s nothing happening in fundamental physics.

Then, just a couple of months later, the prestigious (if tamely titled) journal Physics Letters B published an article that ignited the first superstring revolution, a sweeping movement that inspired thousands of physicists worldwide to drop their research in progress and chase Einstein’s long-sought dream of a unified theory. The field was young, the terrain fertile and the atmosphere electric. The only thing I needed to drop was a neophyte’s inhibition to run with the world’s leading physicists. I did. What followed proved to be the most exciting intellectual odyssey of my life.

That was 30 years ago this month, making the moment ripe for taking stock: Is string theory revealing reality’s deep laws? Or, as some detractors have claimed, is it a mathematical mirage that has sidetracked a generation of physicists?

Unification has become synonymous with Einstein, but the enterprise has been at the heart of modern physics for centuries. Isaac Newton united the heavens and Earth, revealing that the same laws governing the motion of the planets and the Moon described the trajectory of a spinning wheel and a rolling rock. About 200 years later, James Clerk Maxwell took the unification baton for the next leg, showing that electricity and magnetism are two aspects of a single force described by a single mathematical formalism. 

The next two steps, big ones at that, were indeed vintage Einstein. In 1905, Einstein linked space and time, showing that motion through one affects passage through the other, the hallmark of his special theory of relativity. Ten years later, Einstein extended these insights with his general theory of relativity, providing the most refined description of gravity, the force governing the likes of stars and galaxies. With these achievements, Einstein envisioned that a grand synthesis of all of nature’s forces was within reach.

But by 1930, the landscape of physics had thoroughly shifted. Niels Bohr and a generation of intrepid explorers ventured deep into the microrealm, where they encountered quantum mechanics, an enigmatic theory formulated with radically new physical concepts and mathematical rules. While spectacularly successful at predicting the behavior of atoms and subatomic particles, the quantum laws looked askance at Einstein’s formulation of gravity. This set the stage for more than a half-century of despair as physicists valiantly struggled, but repeatedly failed, to meld general relativity and quantum mechanics, the laws of the large and small, into a single all-encompassing description.

Such was the case until December 1984, when John Schwarz, of the California Institute of Technology, and Michael Green, then at Queen Mary College, published a once-in-a-generation paper showing that string theory could overcome the mathematical antagonism between general relativity and quantum mechanics, clearing a path that seemed destined to reach the unified theory. 

The idea underlying string unification is as simple as it is seductive. Since the early 20th century, nature’s fundamental constituents have been modeled as indivisible particles—the most familiar being electrons, quarks and neutrinos—that can be pictured as infinitesimal dots devoid of internal machinery. String theory challenges this by proposing that at the heart of every particle is a tiny, vibrating string-like filament. And, according to the theory, the differences between one particle and another—their masses, electric charges and, more esoterically, their spin and nuclear properties—all arise from differences in how their internal strings vibrate. 

Much as the sonorous tones of a cello arise from the vibrations of the instrument’s strings, the collection of nature’s particles would arise from the vibrations of the tiny filaments described by string theory. The long list of disparate particles that had been revealed over a century of experiments would be recast as harmonious “notes” comprising nature’s score.

Most gratifying, the mathematics revealed that one of these notes had properties precisely matching those of the “graviton,” a hypothetical particle that, according to quantum physics, should carry the force of gravity from one location to another. With this, the worldwide community of theoretical physicists looked up from their calculations. For the first time, gravity and quantum mechanics were playing by the same rules. At least in theory.

I began learning the mathematical underpinnings of string theory during an intense period in the spring and summer of 1985. I wasn’t alone. Graduate students and seasoned faculty alike got swept up in the potential of string theory to be what some were calling the “final theory” or the “theory of everything.” In crowded seminar rooms and flyby corridor conversations, physicists anticipated the crowning of a new order. 

But the simplest and most important question loomed large. Is string theory right? Does the math explain our universe? The description I’ve given suggests an experimental strategy. Examine particles and if you see little vibrating strings, you’re done. It’s a fine idea in principle, but string theory’s pioneers realized it was useless in practice. The math set the size of strings to be about a million billion times smaller than even the minute realms probed by the world’s most powerful accelerators. Save for building a collider the size of the galaxy, strings, if they’re real, would elude brute force detection.

Making the situation seemingly more dire, researchers had come upon a remarkable but puzzling mathematical fact. String theory’s equations require that the universe has extra dimensions beyond the three of everyday experience—left/right, back/forth and up/down. Taking the math to heart, researchers realized that their backs were to the wall. Make sense of extra dimensions—a prediction that’s grossly at odds with what we perceive—or discard the theory.

String theorists pounced on an idea first developed in the early years of the 20th century. Back then, theorists realized that there might be two kinds of spatial dimensions: those that are large and extended, which we directly experience, and others that are tiny and tightly wound, too small for even our most refined equipment to reveal. Much as the spatial extent of an enormous carpet is manifest, but you have to get down on your hands and knees to see the circular loops making up its pile, the universe might have three big dimensions that we all navigate freely, but it might also have additional dimensions so minuscule that they’re beyond our observational reach.

In a paper submitted for publication a day after New Year’s 1985, a quartet of physicists—Philip Candelas, Gary Horowitz, Andrew Strominger and Edward Witten—pushed this proposal one step further, turning vice to virtue. Positing that the extra dimensions were minuscule, they argued, would not only explain why we haven’t seen them, but could also provide the missing bridge to experimental verification.

Strings are so small that when they vibrate they undulate not just in the three large dimensions, but also in the additional tiny ones. And much as the vibrational patterns of air streaming through a French horn are determined by the twists and turns of the instrument, the vibrational patterns of strings would be determined by the shape of the extra dimensions. Since these vibrational patterns determine particle properties like mass, electric charge and so on—properties that can be detected experimentally—the quartet had established that if you know the precise geometry of the extra dimensions, you can make predictions about the results that certain experiments would observe.

For me, deciphering the paper’s equations was one of those rare mathematical forays bordering on spiritual enlightenment. That the geometry of hidden spatial dimensions might be the universe’s Rosetta stone, embodying the secret code of nature’s fundamental constituents—well, it was one of the most beautiful ideas I’d ever encountered. It also played to my strength. As a mathematically oriented physics student, I’d already expended great effort studying topology and differential geometry, the very tools needed to analyze the mathematical form of extra-dimensional spaces.

And so, in the mid-1980s, with a small group of researchers at Oxford, we set our sights on extracting string theory’s predictions. The quartet’s paper had delineated the category of extra-dimensional spaces allowed by the mathematics of string theory and, remarkably, only a handful of candidate shapes were known. We selected one that seemed most promising, and embarked on grueling days and sleepless nights, filled with arduous calculations in higher dimensional geometry and fueled by grandiose thoughts of revealing nature’s deepest workings.

The final results that we found successfully incorporated various established features of particle physics and so were worthy of attention (and, for me, a doctoral dissertation), but were far from providing evidence for string theory. Naturally, our group and many others turned back to the list of allowed shapes to consider other possibilities. But the list was no longer short. Over the months and years, researchers had discovered ever larger collections of shapes that passed mathematical muster, driving the number of candidates into the thousands, millions, billions and then, with insights spearheaded in the mid-1990s by Joe Polchinski, into numbers so large that they’ve never been named. 

Against this embarrassment of riches, string theory offered no directive regarding which shape to pick. And as each shape would affect string vibrations in different ways, each would yield different observable consequences. The dream of extracting unique predictions from string theory rapidly faded.

From a public relations standpoint, string theorists had not prepared for this development. Like the Olympic athlete who promises eight gold medals but wins “only” five, theorists had consistently set the bar as high as it could go. That string theory unites general relativity and quantum mechanics is a profound success. That it does so in a framework with the capacity to embrace the known particles and forces makes the success more than theoretically relevant. Seeking to go even further and uniquely explain the detailed properties of the particles and forces is surely a noble goal, but one that lies well beyond the line dividing success from failure.

Nevertheless, critics who had bristled at string theory’s meteoric rise to dominance used the opportunity to trumpet the theory’s demise, blurring researchers’ honest disappointment of not reaching hallowed ground with an unfounded assertion that the approach had crashed. The cacophony grew louder still with a controversial turn articulated most forcefully by one of the founding fathers of string theory, the Stanford University theoretical physicist Leonard Susskind.

In August 2003, I was sitting with Susskind at a conference in Sigtuna, Sweden, discussing whether he really believed the new perspective he’d been expounding or was just trying to shake things up. “I do like to stir the pot,” he told me in hushed tones, feigning confidence, “but I do think this is what string theory’s been telling us.”

Susskind was arguing that if the mathematics does not identify one particular shape as the right one for the extra dimensions, perhaps there isn’t a single right shape. That is, maybe all of the shapes are right shapes in the sense that there are many universes, each with a different shape for the extra dimensions.

Our universe would then be just one of a vast collection, each with detailed features determined by the shape of their extra dimensions. Why, then, are we in this universe instead of any other? Because the shape of the hidden dimensions yields the spectrum of physical features that allow us to exist. In another universe, for example, the different shape might make the electron a little heavier or the nuclear force a little weaker, shifts that would cause the quantum processes that power stars, including our sun, to halt, interrupting the relentless march toward life on Earth.

Radical though this proposal may be, it was supported by parallel developments in cosmological thinking that suggested that the Big Bang may not have been a unique event, but was instead one of innumerable bangs spawning innumerable expanding universes, called the multiverse. Susskind was suggesting that string theory augments this grand cosmological unfolding by adorning each of the universes in the multiverse with a different shape for the extra dimensions.

With or without string theory, the multiverse is a highly controversial schema, and deservedly so. It not only recasts the landscape of reality, but shifts the scientific goal posts. Questions once deemed profoundly puzzling—why do nature’s numbers, from particle masses to force strengths to the energy suffusing space, have the particular values they do?—would be answered with a shrug. The detailed features we observe would no longer be universal truths; instead, they’d be local bylaws dictated by the particular shape of the extra dimensions in our corner of the multiverse.

Most physicists, string theorists among them, agree that the multiverse is an option of last resort. Yet, the history of science has also convinced us to not dismiss ideas merely because they run counter to expectation. If we had, our most successful theory, quantum mechanics, which describes a reality governed by wholly peculiar waves of probability, would be buried in the trash bin of physics. As Nobel laureate Steven Weinberg has said, the universe doesn’t care about what makes theoretical physicists happy.

This spring, after nearly two years of upgrades, the Large Hadron Collider will crackle back to life, smashing protons together with almost twice the energy achieved in its previous runs. Sifting through the debris with the most complex detectors ever built, researchers will be looking for evidence of anything that doesn’t fit within the battle-tested “Standard Model of particle physics,” whose final prediction, the Higgs boson, was confirmed just before the machine went on hiatus. While it is likely that the revamped machine is still far too weak to see strings themselves, it could provide clues pointing in the direction of string theory. 

Many researchers have pinned their hopes on finding a new class of so-called “supersymmetric” particles that emerge from string theory’s highly ordered mathematical equations. Other collider signals could show hints of extra-spatial dimensions, or even evidence of microscopic black holes, a possibility that arises from string theory’s exotic treatment of gravity on tiny distance scales.

While none of these predictions can properly be called a smoking gun—various non-stringy theories have incorporated them too—a positive identification would be on par with the discovery of the Higgs particle, and would, to put it mildly, set the world of physics on fire. The scales would tilt toward string theory.

But what happens in the event—likely, according to some—that the collider yields no remotely stringy signatures?

Experimental evidence is the final arbiter of right and wrong, but a theory’s value is also assessed by the depth of influence it has on allied fields. By this measure, string theory is off the charts. Decades of analysis filling thousands of articles have had a dramatic impact on a broad swath of research cutting across physics and mathematics. Take black holes, for example. String theory has resolved a vexing puzzle by identifying the microscopic carriers of their internal disorder, a feature discovered in the 1970s by Stephen Hawking. 

Looking back, I’m gratified at how far we’ve come but disappointed that a connection to experiment continues to elude us. While my own research has migrated from highly mathematical forays into extra-dimensional arcana to more applied studies of string theory’s cosmological insights, I now hold only modest hope that the theory will confront data during my lifetime. 

Even so, string theory’s pull remains strong. Its ability to seamlessly meld general relativity and quantum mechanics remains a primary achievement, but the allure goes deeper still. Within its majestic mathematical structure, a diligent researcher would find all of the best ideas physicists have carefully developed over the past few hundred years. It’s hard to believe such depth of insight is accidental.

I like to think that Einstein would look at string theory’s journey and smile, enjoying the theory’s remarkable geometrical features while feeling kinship with fellow travelers on the long and winding road toward unification. All the same, science is powerfully self-correcting. Should decades drift by without experimental support, I imagine that string theory will be absorbed by other areas of science and mathematics, and slowly shed a unique identity. In the interim, vigorous research and a large dose of patience are surely warranted. If experimental confirmation of string theory is in the offing, future generations will look back on our era as transformative, a time when science had the fortitude to nurture a remarkable and challenging theory, resulting in one of the most profound steps toward understanding reality.

Source: http://www.smithsonianmag.com/science-nature/string-theory-about-unravel-180953637/?all

Printing the future | sci-english.blogspot.com

3D printing may be the way mass manufacture is going, but it is also bringing out the artisan in all of us. Tim Dean looks at some of the many ways we can use this new technology. 

One moment it’s an image on a screen, the next it’s an object in your hands – today’s 3D printers make Star Trek gadgets look tame. 
Futuristic as they are, they are also taking us back to a time when individuals were able to craft their own designs. While conventional manufacturing excels at churning out mountains of identical objects, 3D printing gives today’s artisans free reign.
Here are some examples. But this is just the beginning – 3D printing is limited only by our imaginations.

Bespoke bike | sci-english.blogspot.com

Bespoke bike

Every body is different. So wouldn’t it be great if your bike were tailored to yours? Matthew Andrew, owner and designer at Flying Machine in Perth, can oblige. He teamed up with the CSIRO’s Lab 22 to produce a prototype bike, above, with 3D-printed titanium parts that can be tailored to the customer’s size.
“The customer is measured up. It’s similar to buying a tailored suit. You just can’t do that with traditional manufacturing,” says Andrew.
He is already taking orders. Prices will be around $3,000 for the frame, making the bikes a premium option but by no means the most expensive on the market.

Anatomy in print |

Anatomy in print

Most people don’t appreciate being poked, prodded and dissected, so anatomy classes typically use cadavers. But they’re not easy to come by. They require expensive treatment to keep them preserved and many places restrict their use. Enter 3D printed body parts.
Paul McMenamin, director of the Centre for Human Anatomy Education at Monash University, and colleagues have scanned some of the best preserved specimens in their collection and reproduced them using a 3D printer. The results are highly detailed, accurate in terms of colour, odour free and far less expensive than plastic-impregnated “plastinated” specimens, such as those seen in the Body Worlds exhibition.
Even experienced surgeons are using these 3D-printed models, like the one pictured above, to perfect delicate operations before attempting them in the operating theatre.

Home is where you print it |

Home is where you print it

3D printing can make big objects too. In early 2014 WinSun Decoration Design Engineering Co. in China built several houses outside Shanghai using an enormous 3D printer, as seen above. This changed the building method – these houses did not rise from the ground in the conventional manner. Rather, the basic structural elements were printed using an automated gantry arm to extrude a mixture of high grade concrete and glass fibre. The parts were then assembled. The company’s aim is to build up to 10 houses a day at a cost of around $5,000 each.
A similar demonstration is slowly taking shape in Amsterdam at the 3D Print Canal House, led by DUS architects. Instead of concrete, DUS is using a custom granular plastic made from 80% vegetable oil that melts at 170°C. An oversized 3D printer called KamerMaker (or “room builder”) melts the plastic and extrudes it layer by layer to form the structural elements, which can also have cosmetic elements built in.
The lessons learnt from the project will inform 3D-printed house designs around the world.

Printing in the air

Objects built to fly need to be lightweight, strong and constructed to an exacting level of precision. These properties can readily be delivered by 3D printing, which is one reason the aerospace industry has been among the first to embrace the technology.
Airbus recently teamed up with German company Concept Laser to develop 3D-printed titanium parts, above, for its next generation A350 XWB passenger jet. One part is a complex fuel pipe that normally requires 10 individual components to be welded together. The 3D-printed version merged all 10 parts into one, no welding required. The end result is quicker to build, weighs less and costs only a fraction of the conventionally made part.

5G networks: Futuristic communications for today's users | sci-english.blogspot.com

5G networks: Futuristic communications for today's users

 

5G networks | sci-english.blogspot.com

Devices that learn from our habits and help us to "think better," connect us to a friend just by thinking about them, or ensure continuing medical monitoring, will be a reality in 2020, thanks to the 5G technology presented today at the Spanish Royal Academy of Engineering.

"With 5G networks, the society we live in will become fully connected, not only with other people but with the objects around us, and those objects among themselves: this is truly a technological and social revolution", summed up for EfeFuturo Professor Arturo Azcorra, Telefónica-UC3M endowed chair holder and Director at IMDEA Networks.
These systems with "almost infinite capacity and coverage," that will be a thousand times more competent than mobile networks today, "will render time and distance inconsequential," the Professor assures us.
"When we achieve a flow of information that exceeds what one person needs or can process on a device, we consider this as immediate response for the user," we are told by this expert on devices processing 5 GB per second.
Material support for this technology ranges from the "conventional" Google Glasses, some of whose features are yet to be developed, to "chips embedded in the user or headsets whose interface interacts directly with the brain"; therefore, "this will not be a display showing information superposed images, but that reconstructs the image itself" highlighting, for example, those items that most interest us.
This communications system will be similar to sense translators for the disabled which by means of sensors can transform, for example, an image into electrical impulses that can be picked up by the visually impaired.
Users will surpass so-called "augmented reality," going a step further: "it will no longer be necessary to select 'contacts' on your mobile, it will be inside you and you'll call up a friend by just wishing it; you will not need an appointment to see the doctor, your condition will always be known by your GP thanks to sensors monitoring your health", says the expert as an example, "you'll be a permanently logged on browser."
5G networks will also have the capacity to "learn from our preferences and habits to help us think better, all in a most natural way", Azcorra assures us, although he is aware of the implications "at very many levels" that this innovation will have: from limited access to medical records, to child protection or the need to draft new laws, among others.
"People are afraid of any powerful technology, but these systems are designed to contain their problems," the professor adds, declaring he is convinced that this technology will be used by "millions and millions of people" -some 7000 million terminals-, which, by and large, will contribute to lowering costs.
Considering that between 5 and 7% of total world expenditure on energy is on current mobile technologies, "it is clear that 5G cannot be considered as a luxury, it will be available to everyone worldwide and, whether we like it or not, we will all be connected", he predicts.
"Mankind has shown that in 99% of cases it uses technology for its own good", concludes Professor Azcorra, dismissing the remaining 1% risk. EFEfuturo

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Story Source:
The above story is based on materials provided by IMDEA Networks Institute. Note: Materials may be edited for content and length.

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