Shh! Proven security for your secrets

Source: Kyoto University

Summary:

Researchers show the security of their cipher based on chaos theory. The research highlights that their Vector Stream Cipher is not only secure, but structurally simple and low on memory usage compared with existing technology, making it useful for high-density data transmission applications such as in 5G mobile networks and 4K television broadcasts.

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              How do we know if the electronic keys we use in our devices are really secure?

While it is possible to rigorously test the strength of a cipher a kind of digital data lock there are rarely any definitive proofs of unbreakability. Ciphers are highly complex, and while they may ward off certain attacks, they might be vulnerable to others.
Now, in a series of papers published in IEEE Transactions on Information Forensics and Security and IEICE Nonlinear Theory and Its Applications, researchers from Kyoto University have definitively demonstrated the strength of a cipher which is based on principles of chaos theory.
The group's Vector Stream Cipher or VSC this is the first example of a 128-bit key chaotic cipher with provable security.
             "We first developed VSC in 2004 as a simple, fast cipher, and parts of it have already been utilized in the private sector," explains Ken Umeno, leader of the study. "Many theoretical attacks in the past have failed to break it, but until now we hadn't shown definitive proof of security."
The researchers conducted a number of tests, such as a method to evaluate the lock's randomness. Many ciphers rely on number sequences that appear to be random, but are actually generated through recurring relations that are vulnerable to being reproduced.
         "Before evaluating the security of VSC with randomness tests, we found a way to make it significantly more reliable and sensitive," continues Umeno. "We then continued this refinement during the actual investigation."
The research highlights that VSC is not only secure, but structurally simple and low on memory usage compared with existing technology, making it useful for high-density data transmission applications such as in 5G mobile networks and 4K television broadcasts.
           Umeno concludes, "Chaotic ciphers have been in use for about 30 years, but before this study we had not expected to find proof of security. We hope that our work will be studied widely and applied throughout our digital world."

Adapters enable better communication between machines

Source: Karlsruhe Institute of Technology

Summary:

Plug and play is a technology that allows users to connect devices such as printers or USB memory sticks to a computer and directly use them without installing any software. This technology is now also available for industrial applications: Engineers developed an adapter that makes it much easier to interconnect parts of a production facility and align them with each other.

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                  Small connector, big effect: This plug-and-play adapter overcomes language barriers between machines and facilitates modifications of industrial facilities.

Credit: KIT

                   Plug and play is a technology that allows users to connect devices such as printers or USB memory sticks to a computer and directly use them without installing any software. This technology is now also available for industrial applications: Engineers of Karlsruhe Institute of Technology (KIT) developed an adapter that makes it much easier to interconnect parts of a production facility and align them with each other. It allows a much quicker, more flexible and safer modification or extension of such facilities.

                  "It was our objective to reduce the overhead required for commissioning components and entire production facilities," David Barton of the Institute of Production Science (wbk) of KIT says. The problem: Machines and parts that are part of an intelligent, networked production are supposed to exchange information on the current status of production, as demanded by Industry 4.0, but they often do not speak the same language or do not provide the required digital information at all. In addition, the facilities should be convertible so that individual customer demands can be met quickly and cost-effectively. The solution: Within the scope of the "Secure Plug and Work" project, the scientists developed an adapter that bridges communication gaps, for example between components and machine tools.
                    "Our adapter transmits measured values and data as well as their meaning," explains Barton. "For data exchange and storage, we implemented current standards so that production-relevant information can be stored and transmitted safely," Barton says. "A small PC is used as an interface to connect sensors and actuators that convert their signals into mechanical movements." The computer combines the sensor signals with a description file to provide the network with up-to-date information on the component. This description enables the machine control to individually adapt to the components built into the machine tool. The adapter is equipped with an additional 'dongle' that confirms the authenticity of the components. "For production companies, it is now very easy to modify or extend a machine tool by connecting various components via a universal interface without running the risk that unauthorized persons can tamper with the production," Barton explains.
                   In the "Secure Plug and Work" project, the wbk cooperated closely with the IOSB and ISI Fraunhofer Institutes and partners from the industry: MAG, Steinmeyer, Kessler, Romai, Schunk, MOC, cbb, and Wibu. The researchers had the opportunity to test the adapter in various real-world use cases. The Federal Ministry of Education and Research funded the project with approx. EUR 2.5 million.
From September 18 to 23, the wbk will present its plug-and-work approach at the EMO (international machine tool exposition) in Hanover (Germany).

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In the fast lane: Conductive electrodes are key to fast-charging batteries

Researchers use mxene to push charging rate limits in energy storage

Source: Drexel University

Summary:

Can you imagine fully charging your cell phone in just a few seconds? Researchers can, and they took a big step toward making it a reality with their recent work unveiling of a new battery electrode design.

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              Drexel University researchers have developed two new electrode designs, using MXene material, that will allow batteries to charge much faster. The key is a microporous design that allows ions to quickly make their way to redox active sites.

Credit: Drexel University

              Can you imagine fully charging your cell phone in just a few seconds? Researchers in Drexel University's College of Engineering can, and they took a big step toward making it a reality with their recent work unveiling of a new battery electrode design in the journal Nature Energy.

The team, led by Yury Gogotsi, PhD, Distinguished University and Bach professor in Drexel's College of Engineering, in the Department of Materials Science and Engineering, created the new electrode designs from a highly conductive, two-dimensional material called MXene. Their design could make energy storage devices like batteries, viewed as the plodding tanker truck of energy storage technology, just as fast as the speedy supercapacitors that are used to provide energy in a pinch -- often as a battery back-up or to provide quick bursts of energy for things like camera flashes.
               "This paper refutes the widely accepted dogma that chemical charge storage, used in batteries and pseudocapacitors, is always much slower than physical storage used in electrical double-layer capacitors, also known as supercapacitors," Gogotsi said. "We demonstrate charging of thin MXene electrodes in tens of milliseconds. This is enabled by very high electronic conductivity of MXene. This paves the way to development of ultrafast energy storage devices than can be charged and discharged within seconds, but store much more energy than conventional supercapacitors."
The key to faster charging energy storage devices is in the electrode design. Electrodes are essential components of batteries, through which energy is stored during charging and from which it is disbursed to power our devices. So the ideal design for these components would be one that allows them to be quickly charged and store more energy.
                To store more energy, the materials should have places to put it. Electrode materials in batteries offer ports for charge to be stored. In electrochemistry, these ports, called "redox active sites" are the places that hold an electrical charge when each ion is delivered. So if the electrode material has more ports, it can store more energy which equates to a battery with more "juice."
Collaborators Patrice Simon, PhD, and Zifeng Lin, from Université Paul Sabatier in France, produced a hydrogel electrode design with more redox active sites, which allows it to store as much charge for its volume as a battery. This measure of capacity, termed "volumetric performance," is an important metric for judging the utility of any energy storage device.
                To make those plentiful hydrogel electrode ports even more attractive to ion traffic, the Drexel-led team, including researchers Maria Lukatskaya, PhD, Sankalp Kota, a graduate student in Drexel's MAX/MXene Research Group led by Michel Barsoum, PhD, distinguished professor in the College of Engineering; and Mengquiang Zhao, PhD, designed electrode architectures with open macroporosity many small openings to make each redox active sites in the MXene material readily accessible to ions.
"In traditional batteries and supercapacitors, ions have a tortuous path toward charge storage ports, which not only slows down everything, but it also creates a situation where very few ions actually reach their destination at fast charging rates," said Lukatskaya, the first author on the paper, who conducted the research as part of the A.J. Drexel Nanomaterials Institute. "The ideal electrode architecture would be something like ions moving to the ports via multi-lane, high-speed 'highways,' instead of taking single-lane roads. Our macroporous electrode design achieves this goal, which allows for rapid charging on the order of a few seconds or less."
                The overarching benefit of using MXene as the material for the electrode design is its conductivity. Materials that allow for rapid flow of an electrical current, like aluminum and copper, are often used in electric cables. MXenes are conductive, just like metals, so not only do ions have a wide-open path to a number of storage ports, but they can also move very quickly to meet electrons there. Mikhael Levi, PhD, and Netanel Shpigel, research collaborators from Bar-Ilan University in Israel, helped the Drexel group maximize the number of the ports accessible to ions in MXene electrodes.
                Use in battery electrodes is just the latest in a series of developments with the MXene material that was discovered by researchers in Drexel's Department of Materials Science and Engineering in 2011. Since then, researchers have been testing them in a variety of applications from energy storage to electromagnetic radiation shielding, and water filtering. This latest development is significant in particular because it addresses one of the primary problems hindering the expansion of the electric vehicle market and that has been lurking on the horizon for mobile devices.
                  "If we start using low-dimensional and electronically conducting materials as battery electrodes, we can make batteries working much, much faster than today," Gogotsi said. "Eventually, appreciation of this fact will lead us to car, laptop and cell-phone batteries capable of charging at much higher rates seconds or minutes rather than hours."

Smallest-ever star discovered by astronomers

Source: University of Cambridge

Summary:

The smallest star yet measured has been discovered by a team of astronomers. With a size just a sliver larger than that of Saturn, the gravitational pull at its stellar surface is about 300 times stronger than what humans feel on Earth.

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            Smallest star ever discovered. Very small and dim stars are the best possible candidates for detecting Earth-sized planets which can have liquid water on their surfaces.

Credit: Amanda Smith

            The smallest star yet measured has been discovered by a team of astronomers led by the University of Cambridge. With a size just a sliver larger than that of Saturn, the gravitational pull at its stellar surface is about 300 times stronger than what humans feel on Earth.

The star is likely as small as stars can possibly become, as it has just enough mass to enable the fusion of hydrogen nuclei into helium. If it were any smaller, the pressure at the centre of the star would no longer be sufficient to enable this process to take place. Hydrogen fusion is also what powers the Sun, and scientists are attempting to replicate it as a powerful energy source here on Earth.
             These very small and dim stars are also the best possible candidates for detecting Earth-sized planets which can have liquid water on their surfaces, such as TRAPPIST-1, an ultracool dwarf surrounded by seven temperate Earth-sized worlds.
The newly-measured star, called EBLM J0555-57Ab, is located about six hundred light years away. It is part of a binary system, and was identified as it passed in front of its much larger companion, a method which is usually used to detect planets, not stars. Details will be published in the journal Astronomy & Astrophysics.
             “Our discovery reveals how small stars can be,” said Alexander Boetticher, the lead author of the study, and a Master’s student at Cambridge’s Cavendish Laboratory and Institute of Astronomy. “Had this star formed with only a slightly lower mass, the fusion reaction of hydrogen in its core could not be sustained, and the star would instead have transformed into a brown dwarf.”
EBLM J0555-57Ab was identified by WASP, a planet-finding experiment run by the Universities of Keele, Warwick, Leicester and St Andrews. EBLM J0555-57Ab was detected when it passed in front of, or transited, its larger parent star, forming what is called an eclipsing stellar binary system. The parent star became dimmer in a periodic fashion, the signature of an orbiting object. Thanks to this special configuration, researchers can accurately measure the mass and size of any orbiting companions, in this case a small star. The mass of EBLM J0555-57Ab was established via the Doppler, wobble method, using data from the CORALIE spectrograph.
               “This star is smaller, and likely colder than many of the gas giant exoplanets that have so far been identified,” said von Boetticher. “While a fascinating feature of stellar physics, it is often harder to measure the size of such dim low-mass stars than for many of the larger planets. Thankfully, we can find these small stars with planet-hunting equipment, when they orbit a larger host star in a binary system. It might sound incredible, but finding a star can at times be harder than finding a planet.”
This newly-measured star has a mass comparable to the current estimate for TRAPPIST-1, but has a radius that is nearly 30% smaller. “The smallest stars provide optimal conditions for the discovery of Earth-like planets, and for the remote exploration of their atmospheres,” said co-author Amaury Triaud, senior researcher at Cambridge’s Institute of Astronomy. “However, before we can study planets, we absolutely need to understand their star; this is fundamental.”
                 Although they are the most numerous stars in the Universe, stars with sizes and masses less than 20% that of the Sun are poorly understood, since they are difficult to detect due to their small size and low brightness. The EBLM project, which identified the star in this study, aims to plug that lapse in knowledge. “Thanks to the EBLM project, we will achieve a far greater understanding of the planets orbiting the most common stars that exist, planets like those orbiting TRAPPIST-1,” said co-author Professor Didier Queloz of Cambridge’ Cavendish Laboratory.

NASA's Juno Spacecraft Spots Jupiter's Great Red Spot

Source: NASA/Jet Propulsion Laboratory

Summary:

Images of Jupiter's Great Red Spot reveal a tangle of dark, veinous clouds weaving their way through a massive crimson oval. The JunoCam imager aboard NASA's Juno mission snapped pics of the most iconic feature of the solar system's largest planetary inhabitant during its July 10 flyby.

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            This enhanced-color image of Jupiter's Great Red Spot was created by citizen scientist Jason Major using data from the JunoCam imager on NASA's Juno spacecraft. The image was taken on July 10, 2017 at 07:10 p.m. PDT (10:10 p.m. EDT), as the Juno spacecraft performed its 7th close flyby of Jupiter. At the time the image was taken, the spacecraft was about 8,648 miles (13,917 kilometers) from the tops of the clouds of the planet.

Credit: NASA/JPL-Caltech/SwRI/MSSS/Jason Major

           Images of Jupiter's Great Red Spot reveal a tangle of dark, veinous clouds weaving their way through a massive crimson oval. The JunoCam imager aboard NASA's Juno mission snapped pics of the most iconic feature of the solar system's largest planetary inhabitant during its Monday (July 10) flyby. The images of the Great Red Spot were downlinked from the spacecraft's memory on Tuesday and placed on the mission's JunoCam website Wednesday morning.

            "For hundreds of years scientists have been observing, wondering and theorizing about Jupiter's Great Red Spot," said Scott Bolton, Juno principal investigator from the Southwest Research Institute in San Antonio. "Now we have the best pictures ever of this iconic storm. It will take us some time to analyze all the data from not only JunoCam, but Juno's eight science instruments, to shed some new light on the past, present and future of the Great Red Spot."
            As planned by the Juno team, citizen scientists took the raw images of the flyby from the JunoCam site and processed them, providing a higher level of detail than available in their raw form. The citizen-scientist images, as well as the raw images they used for image processing, can be found at: https://www.missionjuno.swri.edu/junocam/processing
             "I have been following the Juno mission since it launched," said Jason Major, a JunoCam citizen scientist and a graphic designer from Warwick, Rhode Island. "It is always exciting to see these new raw images of Jupiter as they arrive. But it is even more thrilling to take the raw images and turn them into something that people can appreciate. That is what I live for."
Measuring in at 10,159 miles (16,350 kilometers) in width (as of April 3, 2017) Jupiter's Great Red Spot is 1.3 times as wide as Earth. The storm has been monitored since 1830 and has possibly existed for more than 350 years. In modern times, the Great Red Spot has appeared to be shrinking.
              All of Juno's science instruments and the spacecraft's JunoCam were operating during the flyby, collecting data that are now being returned to Earth. Juno's next close flyby of Jupiter will occur on Sept. 1.
Juno reached perijove (the point at which an orbit comes closest to Jupiter's center) on July 10 at 6:55 p.m. PDT (9:55 p.m. EDT). At the time of perijove, Juno was about 2,200 miles (3,500 kilometers) above the planet's cloud tops. Eleven minutes and 33 seconds later, Juno had covered another 24,713 miles (39,771 kilometers), and was passing directly above the coiling, crimson cloud tops of the Great Red Spot. The spacecraft passed about 5,600 miles (9,000 kilometers) above the clouds of this iconic feature.
              Juno launched on Aug. 5, 2011, from Cape Canaveral, Florida. During its mission of exploration, Juno soars low over the planet's cloud tops -- as close as about 2,100 miles (3,400 kilometers). During these flybys, Juno is probing beneath the obscuring cloud cover of Jupiter and studying its auroras to learn more about the planet's origins, structure, atmosphere and magnetosphere.
              Early science results from NASA's Juno mission portray the largest planet in our solar system as a turbulent world, with an intriguingly complex interior structure, energetic polar aurora, and huge polar cyclones.
"These highly-anticipated images of Jupiter's Great Red Spot are the 'perfect storm' of art and science. With data from Voyager, Galileo, New Horizons, Hubble and now Juno, we have a better understanding of the composition and evolution of this iconic feature," said Jim Green, NASA's director of planetary science.

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The last survivors on Earth may well be the tardigrade

Source: University of Oxford

Summary:

The world's most indestructible species, the tardigrade, an eight-legged micro-animal, also known as the water bear, will survive until the sun dies, according to a new study.

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     Planet Earth. The tardigrade, also known as the water bear, is the toughest, most resilient, form of life on Earth.

Credit: © timothyh / Fotolia

               The world's most indestructible species, the tardigrade, an eight-legged micro-animal, also known as the water bear, will survive until the Sun dies, according to a new Oxford University collaboration.

The new study published in Scientific Reports, has shown that the tiny creatures, will survive the risk of extinction from all astrophysical catastrophes, and be around for at least 10 billion years far longer than the human race.
            Although much attention has been given to the cataclysmic impact that an astrophysical event would have on human life, very little has been published around what it would take to kill the tardigrade, and wipe out life on this planet.
The research implies that life on Earth in general, will extend as long as the Sun keeps shining. It also reveals that once life emerges, it is surprisingly resilient and difficult to destroy, opening the possibility of life on other planets.
               Tardigrades are the toughest, most resilient form of life on earth, able to survive for up to 30 years without food or water, and endure temperature extremes of up to 150 degrees Celsius, the deep sea and even the frozen vacuum of space. The water-dwelling micro animal can live for up to 60 years, and grow to a maximum size of 0.5mm, best seen under a microscope. Researchers from the Universities of Oxford and Harvard, have found that these life forms will likely survive all astrophysical calamities, such as an asteroid, since they will never be strong enough to boil off the world's oceans.
Three potential events were considered as part of their research, including; large asteroid impact, and exploding stars in the form of supernovae or gamma ray bursts.
                                                                                                                                                                       Asteroids
             There are only a dozen known asteroids and dwarf planets with enough mass to boil the oceans (2x10^18 kg), these include (Vesta 2x10^20 kg) and Pluto (10^22 kg), however none of these objects will intersect Earth's orbit and pose a threat to tardigrades.
                                                                                                                                                            Supernova
            In order to boil the oceans an exploding star would need to be 0.14 light-years away. The closest star to the Sun is four light years away and the probability of a massive star exploding close enough to Earth to kill all forms of life on it, within the Sun's lifetime, is negligible.
                                                                                                                                                                   Gamma-Ray bursts
          Gamma-ray bursts are brighter and rarer than supernovae. Much like supernovas, gamma-ray bursts are too far away from earth to be considered a viable threat. To be able to boil the world's oceans the burst would need to be no more than 40 light-years away, and the likelihood of a burst occurring so close is again, minor.
           Dr Rafael Alves Batista, Co-author and Post-Doctoral Research Associate in the Department of Physics at Oxford University, said: 'Without our technology protecting us, humans are a very sensitive species. Subtle changes in our environment impact us dramatically. There are many more resilient species' on earth. Life on this planet can continue long after humans are gone.
'Tardigrades are as close to indestructible as it gets on Earth, but it is possible that there are other resilient species examples elsewhere in the universe. In this context there is a real case for looking for life on Mars and in other areas of the solar system in general. If Tardigrades are earth's most resilient species, who knows what else is out there.'
             Dr David Sloan, Co-author and Post-Doctoral Research Associate in the Department of Physics at Oxford University, said: 'A lot of previous work has focused on 'doomsday' scenarios on Earth astrophysical events like supernovae that could wipe out the human race. Our study instead considered the hardiest species the tardigrade. As we are now entering a stage of astronomy where we have seen exoplanets and are hoping to soon perform spectroscopy, looking for signatures of life, we should try to see just how fragile this hardiest life is. To our surprise we found that although nearby supernovae or large asteroid impacts would be catastrophic for people, tardigrades could be unaffected. Therefore it seems that life, once it gets going, is hard to wipe out entirely. Huge numbers of species, or even entire genera may become extinct, but life as a whole will go on.'
            In highlighting the resilience of life in general, the research broadens the scope of life beyond Earth, within and outside of this solar system. Professor Abraham Loeb, co-author and chair of the Astronomy department at Harvard University, said: 'It is difficult to eliminate all forms of life from a habitable planet. The history of Mars indicates that it once had an atmosphere that could have supported life, albeit under extreme conditions. Organisms with similar tolerances to radiation and temperature as tardigrades could survive long-term below the surface in these conditions. The subsurface oceans that are believed to exist on Europa and Enceladus, would have conditions similar to the deep oceans of Earth where tardigrades are found, volcanic vents providing heat in an environment devoid of light. The discovery of extremophiles in such locations would be a significant step forward in bracketing the range of conditions for life to exist on planets around other stars.'

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Prelude to global extinction: Human impact on Earth's animals

Biologists say disappearance of species tells only part of the story of human impact on Earth's animals

Date:

July 10, 2017

Source:

Stanford University

Summary:

In the first such global evaluation, biologists found more than 30 percent of all vertebrates have declining populations. They call for curbs on the basic drivers of these losses.

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Tropical forest logging has contributed to population declines in many animals, including the Bornean gibbon, known for its whooping call.

Credit: Gerardo Ceballos

No bells tolled when the last Catarina pupfish on Earth died. Newspapers didn't carry the story when the Christmas Island pipistrelle vanished forever.

Two vertebrate species go extinct every year on average, but few people notice, perhaps because the rate seems relatively slow -- not a clear and present threat to the natural systems we depend on. This view overlooks trends of extreme decline in animal populations, which tell a more dire story with cascading consequences, according to a new study that provides the first global evaluation of these population trends.
"This is the case of a biological annihilation occurring globally, even if the species these populations belong to are still present somewhere on Earth," said co-author Rodolfo Dirzo, a professor of biology.
Mapping loss
A 2015 study co-authored by Paul Ehrlich, professor emeritus of biology, and colleagues showed that Earth has entered an era of mass extinction unparalleled since the dinosaurs died out 66 million years ago. The specter of extinction hangs over about 41 percent of all amphibian species and 26 percent of all mammals, according to the International Union for Conservation of Nature (IUCN), which maintains a list of threatened and extinct species. This global disaster scene has the fingerprints of habitat loss, overexploitation, invasive organisms, pollution, toxification and climate change.
The new analysis, published in Proceedings of the National Academy of Sciences, looks beyond species extinctions to provide a clear picture of dwindling populations and ranges. The researchers mapped the ranges of 27,600 species of birds, amphibians, mammals and reptiles -- a sample representing nearly half of known terrestrial vertebrate species -- and analyzed population losses in a sample of 177 well-studied mammal species between 1990 and 2015.
Using range reduction as a proxy for population loss, the study finds more than 30 percent of vertebrate species are declining in population size and range. Of the 177 mammals for which the researchers had detailed data, all have lost 30 percent or more of their geographic ranges and more than 40 percent have lost more than 80 percent of their ranges. Tropical regions have had the greatest number of decreasing species while temperate regions have seen similar or higher proportions of decreasing species. Particularly hard hit have been the mammals of south and southeast Asia, where all the large-bodied species of mammals analyzed have lost more than 80 percent of their geographic ranges.
The study's maps suggest that as much as 50 percent of the number of animal individuals that once shared Earth have disappeared, as have billions of animal populations. This amounts to "a massive erosion of the greatest biological diversity in the history of Earth," the authors write.
"The massive loss of populations and species reflects our lack of empathy to all the wild species that have been our companions since our origins," said the new study's lead author, Gerardo Ceballos of the National Autonomous University of Mexico. "It is a prelude to the disappearance of many more species and the decline of natural systems that make civilization possible."
Cascading effects
Why does the loss of populations and biological diversity matter? Aside from being what the scientists call a prelude to species extinction, the losses rob us of crucial ecosystem services such as honeybees' crop pollination, pest control and wetlands' water purification. We also lose intricate ecological networks involving animals, plants and microorganisms leading to less resilient ecosystems and pools of genetic information that may prove vital to species' survival in a rapidly changing global environment.
"Sadly, our descendants will also have to do without the aesthetic pleasures and sources of imagination provided by our only known living counterparts in the universe," said Ehrlich.
In the meantime, the overall scope of population losses makes clear the world cannot wait to address biodiversity damage, according to the authors. They call for curbs on the basic drivers of extinction human overpopulation and overconsumption  and challenge society to move away from "the fiction that perpetual growth can occur on a finite planet."
Dirzo is also the Bing Professor in Environmental Science. Dirzo and Ehrlich are senior fellows at the Stanford Woods Institute for the Environment.

Tracking the birth of a 'super-earth'

'Synthetic observations' simulating nascent planetary systems could help explain a puzzle that has vexed astronomers for a long time

Source:

University of Arizona

Summary:

'Synthetic observations' simulating nascent planetary systems could help explain a puzzle how planets form  that has vexed astronomers for a long time.

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           This is an artist’s impression of a young star surrounded by a protoplanetary disk in which planets (not shown to scale) are forming.

Credit: Illustration: ESO/L. Calçada

             A new model giving rise to young planetary systems offers a fresh solution to a puzzle that has vexed astronomers ever since new detection technologies and planet-hunting missions such as NASA's Kepler space telescope have revealed thousands of planets orbiting other stars: While the majority of these exoplanets fall into a category called super-Earths -- bodies with a mass somewhere between Earth and Neptune most of the features observed in nascent planetary systems were thought to require much more massive planets, rivaling or dwarfing Jupiter, the gas giant in our solar system.

In other words, the observed features of many planetary systems in their early stages of formation did not seem to match the type of exoplanets that make up the bulk of the planetary population in our galaxy.
             "We propose a scenario that was previously deemed impossible: how a super-Earth can carve out multiple gaps in disks," says Ruobing Dong, the Bart J. Bok postdoctoral fellow at the University of Arizona's Steward Observatory and lead author on the study, soon to be published in the Astrophysical Journal. "For the first time, we can reconcile the mysterious disk features we observe and the population of planets most commonly found in our galaxy."
How exactly planets form is still an open question with a number of outstanding problems, according to Dong.
            "Kepler has found thousands of planets, but those are all very old, orbiting around stars a few billion years old, like our sun," he explains. "You could say we are looking at the senior citizens of our galaxy, but we don't know how they were born."
To find answers, astronomers turn to the places where new planets are currently forming: protoplanetary disks -- in a sense, baby sisters of our solar system.
Such disks form when a vast cloud of interstellar gas and dust condenses under the effect of gravity before collapsing into a swirling disk. At the center of the protoplanetary disk shines a young star, only a few million years old. As microscopic dust particles coalesce to sand grains, and sand grains stick together to form pebbles, and pebbles pile up to become asteroids and ultimately planets, a planetary system much like our solar system is born.
             "These disks are very short-lived," Dong explains. "Over time the material dissipates, but we don't know exactly how that happens. What we do know is that we see disks around stars that are 1 million years old, but we don't see them around stars that are 10 million years old."
In the most likely scenario, much of the disk's material gets accreted onto the star, some is blown away by stellar radiation and the rest goes into forming planets.
Although protoplanetary disks have been observed in relative proximity to the Earth, it is still extremely difficult to make out any planets that may be forming within. Rather, researchers have relied on features such as gaps and rings to infer the presence of planets.
             "Among the explanations for these rings and gaps, those involving planets certainly are the most exciting and drawing the most attention," says co-author Shengtai Li, a research scientist at Los Alamos National Laboratory in Los Alamos, New Mexico. "As the planet orbits around the star, the argument goes, it may clear a path along its orbit, resulting in the gap we see."
Except that reality is a bit more complicated, as evidenced by two of the most prominent observations of protoplanetary disks, which were made with ALMA, the Atacama Large Millimeter/submillimeter Array in Chile. ALMA is an assembly of radio antennas between 7 and 12 meters in diameter and numbering 66 of them once completed. The images of HL Tau and TW Hydra, obtained in 2014 and 2016, respectively, have revealed the finest details so far in any protoplanetary disk, and they show some features that are difficult, if not impossible, to explain with current models of planetary formation, Dong says.
             "Among the gaps in HL Tau and TW Hya revealed by ALMA, two pairs of them are extremely narrow and very close to each other," he explains. "In conventional theory, it is difficult for a planet to open such gaps in a disk. They can never be this narrow and this close to each other for reasons of the physics involved."
In the case of HL Tau and TW Hya, one would have to invoke two planets whose orbits hug each other very closely a scenario that would not be stable over time and therefore is unlikely.
While previous models could explain large, single gaps believed to be indicative of planets clearing debris and dust in their path, they failed to account for the more intricate features revealed by the ALMA observations.
             The model created by Dong and his co-authors results in what the team calls synthetic observations  simulations that look exactly like what ALMA would see on the sky. Dong's team accomplished this by tweaking the parameters going into the simulation of the evolving protoplanetary disk, such as assuming a low viscosity and adding the dust to the mix. Most previous simulations were based on higher disk viscosity and accounted only for the disk's gaseous component.
"The viscosity in protoplanetary disks may be driven by turbulence and other physical effects," Li says. "It's a somewhat mysterious quantity -- we know it's there, but we don't know its origin or how large its value is, so we think our assumptions are reasonable, considering that they result in the pattern that has actually been observed on the sky."
              Even more important, the synthetic observations emerged from the simulations without the necessity to invoke gas giants the size of Jupiter or larger.
"One super-Earth turned out to be sufficient to create the multiple rings and multiple, narrow gaps we see in the actual observations," Dong says.
As future research uncovers more of the inner workings of protoplanetary disks, Dong and his team will refine their simulations with new data. For now, their synthetic observations offer an intriguing scenario that provides a missing link between the features observed in many planetary infants and their grown-up counterparts.

How true is this? that Generous people live happier lives

Source: University of Zurich

Summary:

Generosity makes people happier, even if they are only a little generous. People who act solely out of self-interest are less happy. Merely promising to be more generous is enough to trigger a change in our brains that makes us happier, neuroeconomists found in a recent study.

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Generosity makes people happier, even if they are only a little generous, suggests new research.

Credit: © MG / Fotolia

              Generosity makes people happier, even if they are only a little generous. People who act solely out of self-interest are less happy. Merely promising to be more generous is enough to trigger a change in our brains that makes us happier. This is what UZH neuroeconomists found in a recent study.

What some have been aware of for a long time, others find hard to believe: Those who are concerned about the well-being of their fellow human beings are happier than those who focus only on their own advancement. Doing something nice for another person gives many people a pleasant feeling that behavioral economists call a warm glow. In collaboration with international researchers, Philippe Tobler and Ernst Fehr from the Department of Economics at the University of Zurich investigated how brain areas communicate to produce this feeling. The results provide insight into the interplay between altruism and happiness.
                                                                                                                                                                      Even a little generosity makes people happier
               In their experiments, the researchers found that people who behaved generously were happier afterwards than those who behaved more selfishly. However, the amount of generosity did not influence the increase in contentment. "You don't need to become a self-sacrificing martyr to feel happier. Just being a little more generous will suffice," says Philippe Tobler.
Before the experiment started, some of the study participants had verbally committed to behaving generously towards other people. This group was willing to accept higher costs in order to do something nice for someone else. They also considered themselves happier after their generous behavior (but not beforehand) than the control group, who had committed to behaving generously toward themselves.
                                                                                                                                                                        Intent alone suffices to cause neural changes
               While the study participants were making their decision to behave or not to behave generously, the researchers examined activity in three areas of the participants' brains: in the temporoparietal junction (where prosocial behavior and generosity are processed), in the ventral striatum (which is associated with happiness), and in the orbitofrontal cortex (where we weigh the pros and cons during decision-making processes). These three brain areas interacted differently, depending on whether the study participants had committed to generosity or selfishness.
Simply promising to behave generously activated the altruistic area of the brain and intensified the interaction between this area and the area associated with happiness. "It is remarkable that intent alone generates a neural change before the action is actually implemented," says Tobler.
                                                                                                                                                                    Benefit from the promise to behave generously
            "Promising to behave generously could be used as a strategy to reinforce the desired behavior, on the one hand, and to feel happier, on the other," says Tobler. His co-author Soyoung Park adds: "There are still some open questions, such as: Can communication between these brain regions be trained and strengthened? If so, how? And, does the effect last when it is used deliberately, that is, if a person only behaves generously in order to feel happier?"
                                                                                                                                                                     About the experiment
             At the beginning of the experiment, the 50 participants were promised a sum of money that they would receive in the next few weeks and were supposed to spend. Half of the study participants committed to spending the money on someone they knew (experimental group, promise of generosity), while the other half committed to spending the money on themselves (control group).
Subsequently, all of the study participants made a series of decisions concerning generous behavior, namely, whether to giving somebody who is close to them a gift of money. The size of the gift and the cost thereof varied: One could, for example, give the other person five francs at a cost of two francs. Or give twenty francs at a cost of fifteen. While the study participants were making these decisions, the researchers measured activity in three brain areas: in the temporoparietal junction, where prosocial behavior and generosity are processed; in the ventral striatum, which is associated with happiness; and in the orbitofrontal cortex, where we weigh the pros and cons during decision-making processes. The participants were asked about their happiness before and after the experiment.

Menstruation doesn't change how your brain works -- period

Normonal changes during the menstrual cycle have no impact on aspects of cognition, study shows

Source: Frontiers

Summary:

It has long been assumed that your period affects your brain's performance. A new study set out to determine whether changes in hormones during the menstrual cycle really do change how well brains work. By increasing the sample size and following participants over more than one menstrual cycle, they found evidence that your brain's performance isn't affected by your cycle.

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Levels of estrogen, progesterone and testosterone in one's system have no impact on the working memory, cognitive bias or ability to pay attention to two things at once.

Credit: © Creative-Touch / Fotolia

                A new study published in Frontiers in Behavioral Neuroscience is setting out to change the way we think about the menstrual cycle. While it's often been assumed that anyone who's menstruating isn't working at top mental pitch, Professor Brigitte Leeners and her team of researchers have found evidence to suggest that that's not the case. They examined three aspects of cognition across two menstrual cycles, and found that the levels of estrogen, progesterone and testosterone in your system have no impact on your working memory, cognitive bias or ability to pay attention to two things at once. While some hormones were associated with changes across one cycle in some of the women taking part, these effects didn't repeat in the following cycle. Overall, none of the hormones the team studied had any replicable, consistent effect on study participants' cognition.

            Professor Leeners, team lead, said: "As a specialist in reproductive medicine and a psychotherapist, I deal with many women who have the impression that the menstrual cycle influences their well-being and cognitive performance." Wondering if this anecdotal evidence could be scientifically proven -- and questioning the methodology of many existing studies on the subject -- the team set out to shed some light on this controversial topic.
The study published today uses a much larger sample than usual, and (unlike most similar studies) follows women across two consecutive menstrual cycles. The team, working from the Medical School Hannover and University Hospital Zürich, recruited 68 women to undergo detailed monitoring to investigate changes in three selected cognitive processes at different stages in the menstrual cycle. While analysis of the results from the first cycle suggested that cognitive bias and attention were affected, these results weren't replicated in the second cycle. The team looked for differences in performance between individuals and changes in individuals' performance over time, and found none.
                Professor Leeners said, "The hormonal changes related to the menstrual cycle do not show any association with cognitive performance. Although there might be individual exceptions, women's cognitive performance is in general not disturbed by hormonal changes occurring with the menstrual cycle."
Professor Leeners cautions, however, that there's more work to do. While this study represents a meaningful step forward, larger samples, bigger subsamples of women with hormone disorders, and further cognitive tests would provide a fuller picture of the way that the menstrual cycle affects the brain. In the meantime, Professor Leeners hopes her team's work will start the long process of changing minds about menstruation.

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Strange silk: Find out Why rappelling spiders don't spin out of control

Dragline silk from golden orb weaver spiders dissipates energy to prevent spinning

Source: American Institute of Physics

Summary:

Researchers show that unlike human hair, metal wires or synthetic fibers, spider silk partially yields when twisted. This property quickly dissipates the energy that would otherwise send an excited spider spinning on the end of its silk. A greater understanding of how spider silk resists spinning could lead to biomimetic fibers that mimic these properties for potential uses in violin strings, helicopter rescue ladders and parachute cords.

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The golden silk orb weaver (Nephila pilipes) creates dragline silk that prevents it from spinning while hanging from its web.

Credit: Kai Peng of Huazhong University of Science and Technology

               The last time you watched a spider drop from the ceiling on a line of silk, it likely descended gracefully on its dragline instead of spiraling uncontrollably, because spider silk has an unusual ability to resist twisting forces.

In a new paper appearing this week in Applied Physics Letters, from AIP Publishing, researchers from China and the U.K. showed that unlike human hair, metal wires or synthetic fibers, spider silk partially yields when twisted. This property quickly dissipates the energy that would otherwise send an excited spider spinning on the end of its silk.
"Spider silk is very different from other, more conventional materials," said Dabiao Liu of Huazhong University of Science and Technology. "We find that the dragline from the web hardly twists, so we want to know why."
              A greater understanding of how spider silk resists spinning could lead to biomimetic fibers that mimic these properties for multiple potential uses such as in violin strings, helicopter rescue ladders and parachute cords. "If we understood how spider silk achieves this, then maybe we could incorporate the properties into our own synthetic ropes," said David Dunstan of Queen Mary University of London.
Spiders use dragline silk for the outer rim and spokes of their webs, and as a lifeline when dropping to the ground. The material has intrigued scientists because of its incredible strength, stretchiness and ability to conduct heat, but little research has focused on its torsional properties -- how it responds to twisting.
Researchers used a torsion pendulum, the same tool used by Henry Cavendish to weigh the Earth in the 1790s, to investigate dragline silk from two species of golden silk orb weavers. They collected strands of silk from captive spiders and suspended the strands inside a cylinder using two washers at the end to mimic a spider. The cylinder isolated the silk from environmental disturbances and kept the strand at a constant humidity, because water can cause the fibers to contract. A rotating turntable twisted the silk while a high-speed camera recorded the silk's back and forth oscillations over hundreds of cycles.
Unlike synthetic fibers and metals, spider silk deforms slightly when twisted, which releases more than 75 percent of its potential energy, and the oscillations rapidly slow. After twisting, the silk partially snaps back.
              The team suspects that this unusual behavior is linked to the silk's complex physical structure, consisting of a core of multiple fibrils inside a skin. Each fibril has segments of amino acids in organized sheets and others in unstructured looping chains. They propose that torsion causes the sheets to stretch like elastic, and warp the hydrogen bonds linking the chains, which deform like plastic. The sheets can recover their original shape, but the chains remain partially deformed. The pendulum exhibits this change with reduced magnitude of the silk's oscillations, as well as a shifting of the equilibrium point of the oscillation.
The group will continue to investigate how spider silk reacts to twisting in this way and is also looking into how it maintains its stiffness during torsion, what effect humidity has and to what degree air helps dissipate the energy. "There is a lot of further work needed," Dunstan said. "This spider silk is displaying a property that we simply don't know how to recreate ourselves, and that is fascinating."

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Your hands may reveal the struggle to maintain self-control

Study shows decision-making in real time

Source: Ohio State University

Summary:

It takes just a few seconds to choose a cookie over an apple and wreck your diet for the day. But what is happening during those few seconds while you make the decision? In a new study, researchers watched in real time as people's hands revealed the struggle they were under to choose the long-term goal over short-term temptation. The work represents a new approach to studying self-control.

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         It takes just a few seconds to choose a cookie over an apple and wreck your diet for the day.

Credit: Jeff Grabmeier

        It takes just a few seconds to choose a cookie over an apple and wreck your diet for the day.

But what is happening during those few seconds while you make the decision?
In a new study, researchers watched in real time as people's hands revealed the struggle they were under to choose the long-term goal over short-term temptation. The work represents a new approach to studying self-control.
            In one key experiment, participants viewed pictures of a healthy and an unhealthy food choice on opposite sides of the top of a computer screen and moved a cursor from the center bottom to select one of the foods.
People who moved the cursor closer to the unhealthy treat (even when they ultimately made the healthy choice) later showed less self-control than did those who made a more direct path to the healthy snack.
"Our hand movements reveal the process of exercising self-control," said Paul Stillman, co-author of the study and postdoctoral researcher in psychology at The Ohio State University.
"You can see the struggle as it happens. For those with low self-control, the temptation is actually drawing their hand closer to the less-healthy choice."
The results may shed light on a scholarly debate about what's happening in the brain when humans harness willpower.
            Stillman conducted the study with Melissa Ferguson, professor of psychology, and Danila Medvedev, a former undergraduate student, both from Cornell University. Their research will appear in the journal Psychological Science.
The study involved several experiments. In one, 81 college students made 100 decisions involving healthy versus unhealthy food choices.
In each trial, they clicked a "Start" button at the bottom of the screen. As soon as they did, two images appeared in the upper-left and upper-right corners of the screen, one a healthy food (such as Brussels sprouts) and the other an unhealthy one (such as a brownie).
They were told to choose as quickly as possible which of the two foods would most help them meet their health and fitness goals. So there was a "correct" answer, even if they were tempted by a less healthy treat.
Before the experiment began, the participants were told that after they finished they would be given one of the foods they chose in the experiment. At the end, however, they could freely choose whether they wanted an apple or a candy bar.
         The results showed that those who chose the candy bar at the end of the experiment those with lower self-control  had tended to veer closer to the unhealthy foods on the screen.
"The more they were pulled toward the temptation on the computer screen, the more they actually chose the temptations and failed at self-control," Stillman said.
But for those with higher levels of self-control, the path to the healthy food was more direct, indicating that they experienced less conflict.
In two other studies, similar results occurred in a completely different scenario, in which college students could decide whether they would rather accept $25 today or $45 in 180 days. Those with lower levels of self-control had mouse trajectories that were clearly different from those with higher self-control, suggesting differences in how they were dealing with the decisions.
            "This mouse-tracking metric could be a powerful new tool to investigate real-time conflict when people have to make decisions related to self-control," he said.
The findings also offer new evidence in a debate about how decision-making in self-control situations unfolds, Stillman said.
When the researchers mapped the trajectories people took with the cursor in the first experiment, they observed that most participants did not automatically start directly toward the unhealthy treat before abruptly switching course back to the healthy food. Rather, the trajectories appear curved, as if both the temptation and goal were competing from the beginning.
                                                                                                                                                                         Why is that important?
         Some researchers have argued that there are two systems in our brain that are involved in a self-control decision: one that's impulsive and a second that overcomes the impulses to exert willpower. But if that were the case, the trajectories seen in this study should look different than they do, Stillman said.
If dual systems underlie these choices, there should be a relatively straight line toward the unhealthy food while people are under the influence of the impulsive first system and then an abrupt change in direction toward the healthy food as the system in charge of self-control kicks in.
"That's not what we found," Stillman said. "Our results suggest a more dynamical process in which the healthy and unhealthy choices are competing from the very beginning in our brains and there isn't an abrupt change in thinking. That's why we get these curved trajectories."
Stillman said these results should help lead to a more accurate view of how our cognitive processes unfold to allow us to resist temptation.

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First battery-free cellphone makes calls by harvesting ambient power

Source: University of Washington

Summary:

Engineers have designed the first battery-free cellphone that can send and receive calls using only a few microwatts of power, which it harvests from ambient radio signals or light. It's a major step forward in moving beyond chargers, cords and dying phones.

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          UW engineers have designed the first battery-free cellphone that can send and receive calls using only a few microwatts of power.

Credit: Mark Stone/University of Washington

University of Washington researchers have invented a cellphone that requires no batteries -- a major leap forward in moving beyond chargers, cords and dying phones. Instead, the phone harvests the few microwatts of power it requires from either ambient radio signals or light.

           The team also made Skype calls using its battery-free phone, demonstrating that the prototype made of commercial, off-the-shelf components can receive and transmit speech and communicate with a base station.
The new technology is detailed in a paper published July 1 in the Proceedings of the Association for Computing Machinery on Interactive, Mobile, Wearable and Ubiquitous Technologies.
"We've built what we believe is the first functioning cellphone that consumes almost zero power," said co-author Shyam Gollakota, an associate professor in the Paul G. Allen School of Computer Science & Engineering at the UW. "To achieve the really, really low power consumption that you need to run a phone by harvesting energy from the environment, we had to fundamentally rethink how these devices are designed."
          The team of UW computer scientists and electrical engineers eliminated a power-hungry step in most modern cellular transmissions converting analog signals that convey sound into digital data that a phone can understand. This process consumes so much energy that it's been impossible to design a phone that can rely on ambient power sources.
Instead, the battery-free cellphone takes advantage of tiny vibrations in a phone's microphone or speaker that occur when a person is talking into a phone or listening to a call.
           An antenna connected to those components converts that motion into changes in standard analog radio signal emitted by a cellular base station. This process essentially encodes speech patterns in reflected radio signals in a way that uses almost no power.
To transmit speech, the phone uses vibrations from the device's microphone to encode speech patterns in the reflected signals. To receive speech, it converts encoded radio signals into sound vibrations that that are picked up by the phone's speaker. In the prototype device, the user presses a button to switch between these two "transmitting" and "listening" modes.
Using off-the-shelf components on a printed circuit board, the team demonstrated that the prototype can perform basic phone functions transmitting speech and data and receiving user input via buttons. Using Skype, researchers were able to receive incoming calls, dial out and place callers on hold with the battery-free phone.
            "The cellphone is the device we depend on most today. So if there were one device you'd want to be able to use without batteries, it is the cellphone," said faculty lead Joshua Smith, professor in both the Allen School and UW's Department of Electrical Engineering. "The proof of concept we've developed is exciting today, and we think it could impact everyday devices in the future."
The team designed a custom base station to transmit and receive the radio signals. But that technology conceivably could be integrated into standard cellular network infrastructure or Wi-Fi routers now commonly used to make calls.
"You could imagine in the future that all cell towers or Wi-Fi routers could come with our base station technology embedded in it," said co-author Vamsi Talla, a former UW electrical engineering doctoral student and Allen School research associate. "And if every house has a Wi-Fi router in it, you could get battery-free cellphone coverage everywhere."
            The battery-free phone does still require a small amount of energy to perform some operations. The prototype has a power budget of 3.5 microwatts.
The UW researchers demonstrated how to harvest this small amount of energy from two different sources. The battery-free phone prototype can operate on power gathered from ambient radio signals transmitted by a base station up to 31 feet away.
Using power harvested from ambient light with a tiny solar cell -- roughly the size of a grain of rice the device was able to communicate with a base station that was 50 feet away.
Many other battery-free technologies that rely on ambient energy sources, such as temperature sensors or an accelerometer, conserve power with intermittent operations. They take a reading and then "sleep" for a minute or two while they harvest enough energy to perform the next task. By contrast, a phone call requires the device to operate continuously for as long as the conversation lasts.
            "You can't say hello and wait for a minute for the phone to go to sleep and harvest enough power to keep transmitting," said co-author Bryce Kellogg, a UW electrical engineering doctoral student. "That's been the biggest challenge -- the amount of power you can actually gather from ambient radio or light is on the order of 1 or 10 microwatts. So real-time phone operations have been really hard to achieve without developing an entirely new approach to transmitting and receiving speech."
Next, the research team plans to focus on improving the battery-free phone's operating range and encrypting conversations to make them secure. The team is also working to stream video over a battery-free cellphone and add a visual display feature to the phone using low-power E-ink screens.

Giant molecular cages made for energy conversion and drug delivery

Source: Trinity College Dublin

Summary:

The porous, 'sponge'-type molecules have an enormous internal surface area. This allows their use as 'molecular flasks' or 'molecular containers' that change the reactivity and properties of encapsulated molecules.

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This is a diagram showing the molecular cage structure.

Credit: Professor Wolfgang Schmitt, Trinity College Dublin

             Scientists from Trinity College Dublin and AMBER, the Science Foundation Ireland-funded materials science research centre hosted in Trinity College Dublin, have created 'molecular cages' that can maximise the efficiency of converting molecules in chemical reactions, and that may in future also be used as sensors and drug-delivery agents. The cages can be packed with different molecules, many of which have a specific task or functionality. Incredibly, a teaspoon of powder containing these cages provides a greater internal surface area to boost reactivity and storage capacity than would be provided by an entire football field (4000 m2/g).

             This enormous intrinsic surface area relative to the weight of the structure in combination with the solubility offers great promise for energy conversion, while the structure blueprint (hollow, with sub-cages) allows different molecules to be discretely contained within. This latter feature is key in increasing the potential uses for these 'metal-organic-organic polyhedra' (MOP), because it means materials can be packed so as to react only when specific conditions present themselves.
One such example is in bio-sensing and drug-delivery, with a biological cue required to kick-start a chemical reaction. For example, a drug could be encapsulated in one of these MOP in the knowledge that it would only be released at the specific target site, where a specific biological molecule would trigger its release.
              The researchers behind the breakthrough, which has just been published in leading international journal Nature Communications, also hope to develop light-active porous, metal-organic materials for use in green energy. The dream would be to create a molecule that could simply use light to convert energy essentially replicating the way plants produce energy via photosynthesis.
Professor in Chemistry at Trinity College Dublin, and Investigator in AMBER, Wolfgang Schmitt, led the research. He said: "We have essentially created a molecular 'flask' or better 'sponge' that can hold different molecules until a specific set of conditions spark them into life."
"Hollow cage-type molecular structures have attracted a lot of scientific attention because of these features, but as the number of potential applications has grown and the target systems and environments become more complex, progress has been hampered by the lack of structures with sufficiently large inner cavities and surface areas."
               "The MOP we have just created is among the largest ever made, comprising a number of internal sub-cages, providing numerous different binding sites. The nano-sized compartments can potentially change the reactivity and properties of molecules that are encapsulated within the confined inner spaces and, as such, these cages can be used to promote distinct chemical reactions. Thus, these molecules have the potential to mimic biological enzymes."
The journal article describes the structure of the new cage molecule, which is composed of 36 copper atoms and is made up of 96 individual components.

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Check out The sharpest laser in the world

New laser with a linewidth of only 10 mHz developed

Source: Physikalisch-Technische Bundesanstalt (PTB)

Summary:

With a linewidth of only 10 mHz, the laser that the researchers have now developed has established a new world record.

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This is one of the two silicon resonators.

Credit: PTB

               No one had ever come so close to the ideal laser before: theoretically, laser light has only one single color (also frequency or wavelength). In reality, however, there is always a certain linewidth. With a linewidth of only 10 mHz, the laser that the researchers from the Physikalisch-Technische Bundesanstalt (PTB) have now developed together with US researchers from JILA, a joint institute of the National Institute of Standards and Technology and the University of Colorado Boulder, has established a new world record. This precision is useful for various applications such as optical atomic clocks, precision spectroscopy, radioastronomy and for testing the theory of relativity. The results have been published in the current issue of Physical Review Letters.

               Lasers were once deemed a solution without problems -- but that is now history. More than 50 years have passed since the first technical realization of the laser, and we cannot imagine how we could live without them today. Laser light is used in numerous applications in industry, medicine and information technologies. Lasers have brought about a real revolution in many fields of research and in metrology -- or have even made some new fields possible in the first place.
One of a laser's outstanding properties is the excellent coherence of the emitted light. For researchers, this is a measure for the light wave's regular frequency and linewidth. Ideally, laser light has only one fixed wavelength (or frequency). In practice, the spectrum of most types of lasers can, however, reach from a few kHz to a few MHz in width, which is not good enough for numerous experiments requiring high precision.
Research has therefore focused on developing ever better lasers with greater frequency stability and a narrower linewidth. Within the scope of a nearly 10-year-long joint project with the US colleagues from JILA in Boulder, Colorado, a laser has now been developed at PTB whose linewidth is only 10 mHz (0.01 Hz), hereby establishing a new world record. "The smaller the linewidth of the laser, the more accurate the measurement of the atom's frequency in an optical clock. This new laser will enable us to decisively improve the quality of our clocks," PTB physicist Thomas Legero explains.
                In addition to the new laser's extremely small linewidth, Legero and his colleagues found out by means of measurements that the emitted laser light's frequency was more precise than what had ever been achieved before. Although the light wave oscillates approx. 200 trillion times per second, it only gets out of sync after 11 seconds. By then, the perfect wave train emitted has already attained a length of approx. 3.3 million kilometers. This length corresponds to nearly ten times the distance between Earth and the moon.
Since there was no other comparably precise laser in the world, the scientists working on this collaboration had to set up two such laser systems straight off. Only by comparing these two lasers was it possible to prove the outstanding properties of the emitted light.
               The core piece of each of the lasers is a 21-cm long Fabry-Pérot silicon resonator. The resonator consists of two highly reflecting mirrors which are located opposite each other and are kept at a fixed distance by means of a double cone. Similar to an organ pipe, the resonator length determines the frequency of the wave which begins to oscillate, i.e., the light wave inside the resonator. Special stabilization electronics ensure that the light frequency of the laser constantly follows the natural frequency of the resonator. The laser's frequency stability -- and thus its linewidth -- then depends only on the length stability of the Fabry-Pérot resonator.
                The scientists at PTB had to isolate the resonator nearly perfectly from all environmental influences which might change its length. Among these influences are temperature and pressure variations, but also external mechanical perturbations due to seismic waves or sound. They have attained such perfection in doing so that the only influence left was the thermal motion of the atoms in the resonator. This "thermal noise" corresponds to the Brownian motion in all materials at a finite temperature, and it represents a fundamental limit to the length stability of a solid. Its extent depends on the materials used to build the resonator as well as on the resonator's temperature.
                For this reason, the scientists of this collaboration manufactured the resonator from single-crystal silicon which was cooled down to a temperature of -150 °C. The thermal noise of the silicon body is so low that the length fluctuations observed only originate from the thermal noise of the dielectric SiO2/Ta2O5 mirror layers. Although the mirror layers are only a few micrometers thick, they dominate the resonator's length stability. In total, the resonator length, however, only fluctuates in the range of 10 attometers. This length corresponds to no more than a ten-millionth of the diameter of a hydrogen atom. The resulting frequency variations of the laser therefore amount to less than 4 × 10-17 of the laser frequency.
The new lasers are now being used both at PTB and at JILA in Boulder to further improve the quality of optical atomic clocks and to carry out new precision measurements on ultracold atoms. At PTB, the ultrastable light from these lasers is already being distributed via optical waveguides and is then used by the optical clocks in Braunschweig.
             "In the future, it is planned to disseminate this light also within a European network. This plan would allow even more precise comparisons between the optical clocks in Braunschweig and the clocks of our European colleagues in Paris and London," Legero says. In Boulder, a similar plan is in place to distribute the laser across a fiber network that connects between JILA and various NIST labs.
The scientists from this collaboration see further optimization possibilities. With novel crystalline mirror layers and lower temperatures, the disturbing thermal noise can be further reduced. The linewidth could then even become smaller than 1 mHz.

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