Amazing Science

MIT researchers find a tabletop all-optical terahertz-driven electron gun could replace car-sized radio-frequency (RF) guns in electron diffraction imaging and ultrafast X-ray imaging.

Ultrashort bursts of electrons have several important applications in scientific imaging, but producing them has typically required a costly, power-hungry apparatus about the size of a car. In the journal Optica, researchers at MIT, the German Synchrotron, and the University of Hamburg in Germany describe a new technique for generating electron bursts, which could be the basis of a shoebox-sized device that consumes only a fraction as much power as its predecessors.

Ultrashort electron beams are used to directly gather information about materials that are undergoing chemical reactions or changes of physical state. But after being fired down a particle accelerator a half a mile long, they’re also used to produce ultrashort X-rays. Last year, in Nature Communications, the same group of MIT and Hamburg researchersreported the prototype of a small “linear accelerator” that could serve the same purpose as the much larger and more expensive particle accelerator. That technology, together with a higher-energy version of the new “electron gun,” could bring the imaging power of ultrashort X-ray pulses to academic and industry labs.

Indeed, while the electron bursts reported in the new paper have a duration measured in hundreds of femtoseconds, or quadrillionths of a second (which is about what the best existing electron guns can manage), the researchers’ approach has the potential to lower their duration to a single femtosecond. An electron burst of a single femtosecond could generate attosecond X-ray pulses, which would enable real-time imaging of cellular machinery in action.

“We’re building a tool for the chemists, physicists, and biologists who use X-ray light sources or the electron beams directly to do their research,” says Ronny Huang, an MIT PhD student in electrical engineering and first author on the new paper. “Because these electron beams are so short, they allow you to kind of freeze the motion of electrons inside molecules as the molecules are undergoing a chemical reaction. A femtosecond X-ray light source requires more hardware, but it utilizes electron guns.”

In particular, Huang explains, with a technique called electron diffraction imaging, physicists and chemists use ultrashort bursts of electrons to investigate phase changes in materials, such as the transition from an electrically conductive to a nonconductive state, and the creation and dissolution of bonds between molecules in chemical reactions.

Ultrashort X-ray pulses have the same advantages that ordinary X-rays do: They penetrate more deeply into thicker materials. The current method for producing ultrashort X-rays involves sending electron bursts from a car-sized electron gun through a billion-dollar, kilometer-long particle accelerator that increases their velocity. Then they pass between two rows of magnets — known as an “undulator” — that converts them to X-rays.

A key glacier in Antarctica is breaking apart from the inside out, suggesting that the ocean is weakening ice on the edges of the continent.

The Pine Island Glacier, part of the ice shelf that bounds the West Antarctic Ice Sheet, is one of two glaciers that researchers believe are most likely to undergo rapid retreat, bringing more ice from the interior of the ice sheet to the ocean, where its melting would flood coastlines around the world.

A nearly 225-square-mile iceberg broke off from the glacier in 2015, but it wasn't until Ohio State University researchers were testing some new image-processing software that they noticed something strange in satellite images taken before the event.

In the images, they saw evidence that a rift formed at the very base of the ice shelf nearly 20 miles inland in 2013. The rift propagated upward over two years, until it broke through the ice surface and set the iceberg adrift over 12 days in late July and early August 2015. They report their discovery in the journal Geophysical Research Letters.

"It's generally accepted that it's no longer a question of whether the West Antarctic Ice Sheet will melt, it's a question of when," said study leader Ian Howat, associate professor of earth sciences at Ohio State. "This kind of rifting behavior provides another mechanism for rapid retreat of these glaciers, adding to the probability that we may see significant collapse of West Antarctica in our lifetimes."

Passengers simmered in Jacuzzis and feasted on gourmet cuisine this summer as the 850-foot cruise ship Crystal Serenity moved through the Northwest Passage.

But in the summer of 1778, when Capt. James Cook tried to find a Western entrance to the route, his men toiled on frost-slicked decks and complained about having to supplement dwindling rations with walrus meat.

The British expedition was halted north of the Bering Strait by "ice which was as compact as a wall and seemed to be 10 or 12 feet high at least," according to the captain's journal. Cook's ships followed the ice edge all the way to Siberia in their futile search for an opening, sometimes guided through fog by the braying of the unpalatable creatures the crew called Sea Horses.

More than two centuries later, scientists are mining meticulous records kept by Cook and his crew for a new perspective on the warming that has opened the Arctic in a way the 18th century explorer could never have imagined. Working with maps and logs from Cook's voyage and other historical records and satellite imagery, University of Washington mathematician Harry Stern has tracked changes in ice cover in the Chukchi Sea, between Alaska and Russia, over nearly 240 years.

The results, published this month in the journal Polar Geography, confirm the significant shrinkage of the summer ice cap and shed new light on the timing of the transformation. The analysis also extends the historical picture back nearly 75 years, building on previous work with ships' records from the 1850s.

"This old data helps us look at what conditions were like before we started global warming, and what the natural variability was," said Jim Overland, a Seattle-based oceanographer for the National Oceanic and Atmospheric Administration who was not involved in Stern's project.

The UN calculates that there are more than 7 billion living humans on Earth, yet 200 years ago we numbered less than 1 billion.1 Recent estimates suggest that 6.5 percent of all people ever born are alive right now.2 This is the most conspicuous fact about world population growth: for thousands of years, population grew only slowly, but in recent centuries it has jumped dramatically. Between 1900 and 2000 the increase in world population was three times greater than the entire previous history of humanity– an increase from 1.5 to 6.1 billion in just 100 years.

A picture of world population in the very long-run fits the pattern of exponential growth (when a population grows exponentially the rate of growth is proportional to the size of the population). Yet an empirical observation of how growth rates have developed in the course of the last century reveals that this pattern no longer holds. The annual rate of population growth has recently been going down. A long historical period of accelerated growth has thus come to an end; the annual world population growth rate peaked in 1962, at around 2.1%, and has come down to almost half since.3

Based on these observations, world history can be divided into three periods marked by distinct trends in population growth. The first period (pre-modernity) was a very long age of very slow population growth. The second period, beginning with the onset of modernity (with rising standards of living and improving health) and lasting until 1962, had an increasing rate of growth. Now that period is over, and the third part of the story has begun; the population growth rate is falling and will likely continue to fall, leading to an end of growth towards the end of this century.

A large space rock came fairly close to Earth on Sunday night. Astronomers knew it wasn't going to hit Earth, thanks in part to a new tool NASA is developing for detecting potentially dangerous asteroids. The tool is a computer program called Scout, and it's being tested at NASA Jet Propulsion Laboratory in Pasadena, Calif. Think of Scout as a celestial intruder alert system. It's constantly scanning data from telescopes to see if there are any reports of so-called Near Earth Objects. If it finds one, it makes a quick calculation of whether Earth is at risk, and instructs other telescopes to make follow-up observations to see if any risk is real.

NASA pays for several telescopes around the planet to scan the skies on a nightly basis, looking for these objects. "The NASA surveys are finding something like at least five asteroids every night," says astronomer Paul Chodas of JPL. But then the trick is to figure out which new objects might hit Earth.

Some children suffer from completely tangled hair, which cannot be combed at all. In German, the phenomenon bears the apt name “uncombable hair syndrome” or even “Struwwelpeter syndrome”. Researchers have identified mutations in three genes that are responsible for this.

Scientists from a total of eight countries were involved in the work. The results were published in the American Journal of Human Genetics.

Many parents know from their own experience that it is not always easy to comb children's hair. Yet with patience and nerves of steel, even the toughest of knots can usually be undone. In the case of "uncombable hair syndrome," brushes and combs don't stand even the hint of a chance. Those affected have extremely frizzy, dry, generally light blonde hair with a characteristic shine, which successfully resists any attempt to tame it. These symptoms are most pronounced in childhood and then ease over time. In adulthood, the hair can more or less be styled normally.

Virtually nothing has so far been known about the causes -- particularly because the phenomenon is relatively rare. It was described in the specialist literature for the first time in 1973; since then, around one hundred cases have been documented worldwide. "However, we assume that there are much more people affected," explains Professor Regina Betz from the Institute for Human Genetics at the University of Bonn. "Those who suffer from uncombable hair do not necessarily seek help for this from a doctor or hospital." Nevertheless, it is known that the anomaly occurs more frequently in some families -- it thus appears to have genetic causes.

Betz is a specialist for rare hereditary hair disorders. A few years ago, she was approached at a conference by a British colleague. He had recently examined a family with two affected children. The Bonn-based human geneticist's interest was piqued. "Via contact with colleagues from around the world, we managed to find nine further children," she explains. The scientists in Bonn sequenced all the genes of those affected. When comparing large databases, they thus came across mutations in three genes that are involved in forming the hair.

The changed genes bear the identifiers PADI3, TGM3 and TCHH. The first two contain the assembly instructions for enzymes, while the third -- TCHH -- contains an important protein for the hair shaft. In healthy hair, the TCHH proteins are joined to each other with extremely fine strands of keratin, which are responsible for the shape and structure of the hair. During this process, the two other identified genes play an important role: "PADI3 changes the hair shaft protein TCHH in such a way that the keratin filaments can adhere to it," explains the lead author of the study, Dr. Fitnat Buket Basmanav Ünalan. "The TGM3 enzyme then produces the actual link."

We're fast approaching the moment when humans and machines merge. Welcome to the Singularity movement.

On Feb. 15, 1965, a diffident but self-possessed high school student named Raymond Kurzweil appeared as a guest on a game show called I've Got a Secret. He was introduced by the host, Steve Allen, then he played a short musical composition on a piano. The idea was that Kurzweil was hiding an unusual fact and the panelists — they included a comedian and a former Miss America — had to guess what it was. On the show (the clip on YouTube), the beauty queen did a good job of grilling Kurzweil, but the comedian got the win: the music was composed by a computer. Kurzweil got $200. (Watch TIME's video "Singularity: How Scared Should We Be?")

Kurzweil then demonstrated 'the computer', which he built himself — a desk-size affair with loudly clacking relays, hooked up to a typewriter. The panelists were pretty blasé about it; they were more impressed by Kurzweil's young age than by anything he had actually done. They were ready to move on to Mrs. Chester Loney of Rough and Ready, Calif., whose secret was that she'd been President Lyndon Johnson's first-grade teacher.

But Kurzweil would spend much of the rest of his career working out what his demonstration meant. Creating a work of art is one of those activities we reserve for humans and humans only. It's an act of self-expression; you're not supposed to be able to do it if you don't have a self. To see creativity, the exclusive domain of humans, usurped by a computer built by a 17-year-old is to watch a line blur that cannot be unblurred, the line between organic intelligence and artificial intelligence.

That was Kurzweil's real secret, and back in 1965 nobody guessed it. Maybe not even him, not yet. But now, 46 years later, Kurzweil believes that we're approaching a moment when computers will become intelligent, and not just intelligent but more intelligent than humans. When that happens, humanity — our bodies, our minds, our civilization — will be completely and irreversibly transformed. He believes that this moment is not only inevitable but imminent. According to his calculations, the end of human civilization as we know it is about 35 years away.

Computers are getting faster. Everybody knows that. Also, computers are getting faster faster — that is, the rate at which they're getting faster is increasing. True? True. So if computers are getting so much faster, so incredibly fast, there might conceivably come a moment when they are capable of something comparable to human intelligence. That 'something' is Artificial intelligence or often called AI. All that horsepower could be put in the service of emulating whatever it is our brains are doing when they create consciousness — not just doing arithmetic very quickly or composing piano music but also driving cars, writing books, making ethical decisions, appreciating fancy paintings, making witty observations at cocktail parties.

If you can swallow that idea, and Kurzweil and a lot of other very smart people can, then all bets are off. From that point on, there's no reason to think computers would stop getting more powerful. They would keep on developing until they were far more intelligent than we are. Their rate of development would also continue to increase, because they would take over their own development from their slower-thinking human creators. Imagine a computer scientist that was itself a super-intelligent computer. It would work incredibly quickly. It could draw on huge amounts of data effortlessly. It wouldn't even take breaks to play Farmville. (See the best inventions of 2010.)

Probably. But it's impossible to predict the behavior of these smarter-than-human intelligences with which (with whom?) we might one day share the planet, because if you could, you'd be as smart as they would be. But there are a lot of theories about it. Maybe we'll merge with them to become super-intelligent cyborgs, using computers to extend our intellectual abilities the same way that cars and planes extend our physical abilities. Maybe the artificial intelligences will help us treat the effects of old age and prolong our life spans indefinitely. Maybe we'll scan our consciousnesses into computers and live inside them as software, forever, virtually. Maybe the computers will turn on humanity and annihilate us. The one thing all these theories have in common is the transformation of our species into something that is no longer recognizable as such to humanity circa 2011. This transformation has a name: the Singularity.

The difficult thing to keep sight of when you're talking about the Singularity is that even though it sounds like science fiction, it isn't, no more than a weather forecast is science fiction. It's not a fringe idea; it's a serious hypothesis about the future of life on Earth. There's an intellectual gag reflex that kicks in anytime you try to swallow an idea that involves super-intelligent immortal cyborgs, but suppress it if you can, because while the Singularity appears to be, on the face of it, preposterous, it's an idea that rewards sober, careful evaluation.

A new technology has been developed that uses nuclear waste to generate electricity in a nuclear-powered battery. A team of physicists and chemists from the University of Bristol have grown a man-made diamond that, when placed in a radioactive field, is able to generate a small electrical current. The development could solve some of the problems of nuclear waste, clean electricity generation and battery life. This innovative method for radioactive energy was presented at the Cabot Institute's sold-out annual lecture - 'Ideas to change the world'- on Friday, 25 November.

Unlike the majority of electricity-generation technologies, which use energy to move a magnet through a coil of wire to generate a current, the man-made diamond is able to produce a charge simply by being placed in close proximity to a radioactive source.

Tom Scott, Professor in Materials in the University's Interface Analysis Centre and a member of the Cabot Institute, said: "There are no moving parts involved, no emissions generated and no maintenance required, just direct electricity generation. By encapsulating radioactive material inside diamonds, we turn a long-term problem of nuclear waste into a nuclear-powered battery and a long-term supply of clean energy."

The technology, used in Google Translate, can translate unseen material between languages. Google has previously taught its artificial intelligence to play games, and it's even capable of creating its own encryption. Now, its language translation tool has used machine learning to create a 'language' all of its own.

In September 2016, the search giant turned on its Google Neural Machine Translation (GNMT) system to help it automatically improve how it translates languages. The machine learning system analyses and makes sense of languages by looking at entire sentences – rather than individual phrases or words.

Following several months of testing, the researchers behind the AI have seen it be able to blindly translate languages even if it's never studied one of the languages involved in the translation. "An example of this would be translations between Korean and Japanese where Korean <> Japanese examples were not shown to the system," the Mike Schuster, from Google Brain wrote in a blogpost.

The team said the system was able to make "reasonable" translations of the languages it had not been taught to translate. In one instance, a research paper published alongside the blog, says the AI was taught Portuguese→English and English→Spanish. It was then able to make translations between Portuguese→Spanish.

"To our knowledge, this is the first demonstration of true multilingual zero-shot translation," the paper explains. To make the system more accurate, the computer scientists then added additional data to the system about the languages.

However, the most remarkable feat of the research paper isn't that an AI can learn to translate languages without being shown examples of them first; it was the fact it used this skill to create its own 'language'. "Visual interpretation of the results shows that these models learn a form of interlingua representation for the multilingual model between all involved language pairs," the researchers wrote in the paper.

An interlingua is a type of artificial language, which is used to fulfill a purpose. In this case, the interlingua was used within the AI to explain how unseen material could be translated. "Using a 3-dimensional representation of internal network data, we were able to take a peek into the system as it translated a set of sentences between all possible pairs of the Japanese, Korean, and English languages," the team's blogpost continued. The data within the network allowed the team to interpret that the neural network was "encoding something" about the semantics of a sentence rather than comparing phrase-to-phrase translations.

Caleb Scharf, an astrophysicist at Columbia University, recently published an article that posits alien life may be so far advanced that we cannot tell it apart from the laws of physics. Is it possible that the universe is potentially teeming with intelligence, it’s just so far ahead of us that it has literally become part of the fabric of space and time? Scharf provides a few ideas on how this might be the case, so let’s unpack this whopper of a speculative hypothesis. He begins with a logical first step, the machine singularity.

Assuming a civilization survives long enough, the ability to bridge the gap between a biological brain and an artificial machine brain may be possible. Once an intelligence becomes one with a computer, and the computational power of the brain exponentially increases, the brain/computer could reach a ‘singularity’, a point at which the entire understanding of the universe becomes child’s play. While this is purely speculative, Scharf points out that some machinations of the universe are so strange that the singularity hypothesis might fit the bill. For example, only 5% of the universe’s mass-energy consists of matter; a larger chunk, about 27%, is spooky dark matter that exists only in models and math, and is yet imperceptible to us.

The relentless drive for energy efficiency in power generation and propulsion places immense value on the development of high-performance materials. Turbine engine efficiency and reduction in carbon emissions are directly related to engine operating temperature. With increasing temperatures, materials start to change in shape or size—a process known as creep—which eventually limits the materials’ performance.

An article appearing this week in Nature Communications shares results of a study titled “Phase transformation strengthening of high-temperature superalloys,” led by Materials Science and Engineering Professor Michael Mills, faculty colleagues Wolfgang Windl, Hamish Fraser and David McComb, and graduate students Tim Smith, Bryan Esser, and Nik Antolin.

“Increased performance in aircraft engines and land-based power generators require the development of a new generation of high-temperature structural materials that are resistant to creep,” said Mills.

This study serves to address a deficit in quantitative, comprehensive understanding of deformation mechanisms for various alloy compositions in high-temperature, high-stress conditions that are relevant to advanced engine designs.

The quantitative analysis combined atomic-resolution imaging with density functional theory (DFT) calculations, led by experts such as Robert Williams at Ohio State’s Center for Electron Microscopy and Analysis (CEMAS) and Anna Carlsson of FEI/Thermo Fisher Scientific. This coupled approach resulted in the discovery of a high-temperature strengthening mechanism, which the research team refers to as phase transformation strengthening.

A discovery that was supposed to help reveal how the bursts arise only thickens the plot.

No astronomer had ever seen anything like it. No theorist had predicted it. Yet there it was — a 5-millisecond radio burst that had arrived on 24 August 2001 from an unknown source seemingly billions of light years away. “It was so bright, we couldn't just dismiss it,” says Duncan Lorimer, who co-discovered the signal1 in 2007 while working on archived data from the Parkes radio telescope in New South Wales, Australia. “But we didn't really know what to do with it.”

Such fleeting radio bursts usually came from pulsars — furiously rotating neutron stars whose radiation sweeps by Earth with the regularity of a lighthouse beam. But Lorimer, an astrophysicist at West Virginia University in Morgantown, saw this object erupt only once, and with more power than any known pulsar.

But when no more bursts appeared, initial excitement turned to doubt. Radio astronomers have learnt to be skeptical of mysterious spikes in their detectors: the events can all too easily result from mobile-phone signals, stray radar probes, strange weather phenomena and instrumental glitches. Wider acceptance of what is now known as the Lorimer burst came only in the past few years, after observers working at Parkes and other telescopes spotted similar signals.

Today, the 2001 event is recognized as the first in a new and exceedingly peculiar class of sources known as fast radio bursts (FRBs) — one of the most perplexing mysteries in astronomy.

A strangely shaped depression on Mars could be a new place to look for signs of life on the Red Planet, according to a University of Texas at Austin-led study.

The depression was probably formed by a volcano beneath a glacier and could have been a warm, chemical-rich environment well suited for microbial life.

The findings were published this month in Icarus, the International Journal of Solar System Studies.