Physics Today’s online staff summarize the most important and interesting news about science from the world's top media outlets.
Nature: The Kuiper belt is the region between 30 AU and 50 AU from the Sun. It is filled with mostly icy remains of the formation of the solar system as well as the dwarf planets Pluto, Haumea, and Makemake. Now, Thayne Currie of the National Astronomical Observatory of Japan and his colleagues have found a star 360 light-years from Earth with a ring of debris orbiting at roughly the same distance as the Kuiper belt is from our Sun. The parent star is 15 million years old, significantly younger than the Sun. That means the system could provide some clues about what our solar system looked like very early in its existence. The team's observations revealed that the star is slightly off center, which suggests that a planet with a mass roughly the same as Jupiter's is also present.
BBC: Shape-memory alloys are metals that can be deformed and then return to their original shape. Some have already found their way into a variety of regular uses, but they all suffer from a high rate of fatigue, which gives them a short useful lifespan. A new alloy developed by Manfred Wuttig of the University of Maryland, College Park, and his colleagues has a lifespan significantly longer than any previous memory alloy. The team subjected 1-cm squares of the material to over 10 million shape distortions caused by both temperature changes and mechanical stresses. The key to the longer life is that as the metal crystallizes, the nickel, titanium, and copper atoms align in a way that lets them easily switch between two different configurations. A lifespan of 10 million cycles should enable a significant number of possible applications.
New Scientist: Another unexpected trait of graphene has been discovered—the ability to be propelled by photon impacts. Yongsheng Chen of Nankai University in Tianjin, China, and his colleagues were using lasers to cut sheets of crumpled graphene oxide, or graphene sponge, for another project and noticed that the graphene was being pushed around. That behavior was unexpected because lasers have never propelled anything larger than individual atoms. Chen's team then put pieces of graphene sponge in a vacuum and shined different wavelengths and intensities of light on them and measured the distance the sponge moved. Even more unusual, the movement was greater than what could be expected from simple momentum transfer from the incoming photons. After further testing, the researchers were able to determine that the sponge builds up a charge from the photon impacts and then adds to its forward momentum by ejecting excess electrons.
New Scientist: One of NASA's current plans is to capture an asteroid and bring it into Earth orbit for research. It's the first step in what some companies hope will be a full-fledged asteroid mining industry. Now Casey Handmer of Caltech and Javier Roa of the Technical University of Madrid are cautioning that dust from asteroid mining could damage satellites in orbit around Earth. According to their model, because an asteroid's gravity is not enough to hold onto loose rocks, up to 5% of the debris that escapes the asteroid could end up in areas through which satellites orbit. They also found that if a 5-m asteroid broke up, it could raise the risk of a satellite–debris collision by as much as 30%.
Nature: Instead of attempting to preprogram robots with solutions to all possible problems, such as failed joints or broken extremities, researchers are attempting to have the robots find a solution themselves. In 2006 a hexapod robot was developed that could identify problems with its legs and create a new way of moving to compensate for the "injury," but it took quite a while to do so. Now Jean-Baptiste Mouret of the French Institute for Research in Computer Science and Automation and his colleagues have simplified the process for the robot so it can find a new movement pattern in under one minute. The robot now has an on-board camera to identify where a problem is, but it does not attempt to diagnose what is wrong. Mouret and his team also include a library of preselected gaits, which they say is similar to an animal's innate knowledge. The library helps the robot rule out nonsensical movements, which significantly reduces the amount of time the robot needs to fix the problem. The improvements allow the robot to compensate not just for the loss of a limb but also for different terrains such as slippery or uneven floors.
Science: The Telescope Array (TA), which is looking for evidence of high-energy cosmic rays, has 507 detectors spread across 700 km in Utah. Yoshiki Tsunesada of the Tokyo Institute of Technology has announced that Japan will be funding another 400 detectors, at a cost of $3.7 million, that will increase the size of the array to nearly 2500 km. TA and other similar arrays are looking for the cascade of particles created when extremely high-energy cosmic rays collide with particles in Earth's atmosphere. Those cosmic rays have energies above 60 EeV, 10 million times higher than any particle accelerator can reach. Physicists hope the extended array will help them determine where the cosmic rays come from.
Ars Technica: The US Air Force has certified private spaceflight company SpaceX's Falcon 9 rocket to launch satellites for the Department of Defense and national security agencies. The certification marks the end of the launch monopoly held by United Launch Alliance (ULA)—the partnership between Boeing and Lockheed—since 2006. Prior to the formation of ULA, the two companies had competed for launch contracts under the Evolved Expendable Launch Vehicle (EELV) system, which started in 1994. The certification process began in December 2014 after SpaceX dropped its lawsuit against the air force over an $11 billion EELV launch contract with ULA that SpaceX felt was unfairly awarded.
Japan Times: In March 2011 three of the six nuclear reactors at the Fukushima Daiichi power plant suffered meltdowns. The disaster triggered the shutdown of all Japan's nuclear reactors pending a safety review. Now commissioners at Japan's Nuclear Regulatory Authority have approved the restart of two nuclear reactors at a power plant on Kyushu, the southernmost of Japan's main islands. Whether Kyushu Electric Power Co will bring the reactors back on line remains to be seen. In the wake of the shutdown, household electricity bills increased by an average of 20%, yet polls indicate the public opposes restarts by two-to-one.
Nature: The first five years after an academic paper is published is a good predictive measure of how influential the paper will be, with most papers' rate of citation slowing over time. However, some papers may wait many years before their importance is recognized and they have sudden spikes in their citation rate. In 2004, papers that fit that behavior were dubbed "sleeping beauties" by Anthony van Raan of Leiden University in the Netherlands. Now Filippo Radicchi of Indiana University Bloomington and his colleagues have analyzed the citation pattern of 22 million papers to rate their "beauty." A paper with a linear citation rate of one per year has a beauty coefficient B of 0. The top paper has a score of B = 11 600. Albert Einstein, Boris Podolsky, and Nathan Rosen's famous paper "Can quantum-mechanical description of physical reality be considered complete?" is the 14th most beautiful.
Science: Around 350 000 people in 66 countries participated in a study of explicit and implicit associations between gender and science. Each participant was asked how strongly they associated being a scientist with being either male or female. Then each participant was asked to categorize displayed words. For some questions, the participants pressed one key to signal "male" or "science" and another key to signal "female" or "liberal arts." For other questions, the keys signaled "male" or "liberal arts" and "female" or "science." The differences in response times are used to determine when the key's gender doesn't align with the participant's implicit bias. Both the explicit and implicit tests showed a global association between being male and being a scientist. The results correlated with the percentage of women in each country earning an undergraduate degree in science.
New York Times: Mosquitoes and other bugs that carry diseases are attracted to the shorter wavelengths emitted by lightbulbs. For that reason, developing bulbs that are less attractive to insects could help reduce the spread of disease. Travis Longcore of the University of Southern California has found that reducing the amount of blue light emitted by LED bulbs attracts 20% fewer bugs than standard LEDs. He compared new "color-tunable" LEDs with off-the-shelf LEDs and fluorescent bulbs, all of which were suspended over soapy water to trap bugs. The LEDs attracted fewer bugs than the fluorescents, which emit widely in the violet and UV wavelengths. The tunable LEDs performed best when the amount of blue light was turned down.
Ars Technica: After a period of extremely frequent impacts from large asteroids that occurred between 4.1 billion and 3.8 billion years ago, there were still occasional major bombardments. Now Donald Lowe of Stanford University and Gary Byerly of Louisiana State University believe they've found evidence of eight large impacts in South Africa. The impact layers date to 3.3 billion years ago and span 250 million years. Each layer contains evidence that the bedrock was vaporized by the impact and was hit by tsunamis soon after. Lowe and Byerly estimate that the asteroids ranged from 20 km to 100 km across. They also propose that two of the impacts were large enough to boil away the ocean at the impact sites. In what they admit is speculative, they suggest that the presence of silica, which precipitated into the layers, is a potential sign that the sea floor was exposed and cracked open by the boiling of the water.
MIT Technology Review: Microsoft's HoloLens combines a video studio with 100 cameras, processing software, and a headset with sensors that detect the surroundings of the wearer. The result is a photorealistic holographic display that is projected into the user's present reality; the headset wearer can interact with the images as if they were solid and real. The headset uses sensor systems to determine how to fit the images to the user's surroundings. This approach is different from most other virtual displays, which block off the outside world. The images can also be presented on two-dimensional displays, and users can interact with them via touchscreens. Microsoft is trying to determine how to reduce the cost of the recording studio to make it more accessible.
Nature: The Open Researcher and Contributor ID (ORCID) scientist registry system has announced that it will include peer-reviewer information in its database. The system will use a standard developed in partnership with the Consortia Advancing Standards in Research Administration Information and publisher Faculty of 1000. The system, which is voluntary, will allow researchers to add to their ORCID profile information about their peer review activities. For journals that participate in the standard, the reviewer's report itself can be added to the profile. For other journals, all that would be stored would be the number of reviews the researcher has completed for the journal in a certain period of time. The American Geophysical Union has already announced that it will use the new standard for its publications.
New Scientist: Vesta is the second most massive and third largest asteroid in the main belt and is classed as a minor planet. Like Ceres and Pallas, the other two most massive and largest asteroids, it doesn't have any natural satellites. That the three largest asteroids don't have any moons is curious because more than 100 main-belt asteroids are known to have other bodies in orbit around them. Vesta in particular looks like it ought to have a moon because its surface shows two large craters whose formation by impact should have created enough debris to form satellites. Lucy McFadden of NASA's Goddard Space Flight Center in Greenbelt, Maryland, and her colleagues examined flyby images from the Dawn spacecraft to confirm the absence of any bodies larger than 6 m orbiting Vesta. Nick Gorkavyi, also of NASA Goddard, suggests that Vesta's high rate of rotation could have resulted in any satellites that formed losing momentum and merging with the asteroid. Gorkavyi says such merging events could explain the large canyons on Vesta's surface.
Los Angeles Times: After studying 74 million deaths in 13 countries between 1985 and 2012, a team led by Antonio Gasparini of the London School of Hygiene and Tropical Medicine has concluded that cold weather is deadlier than hot weather. The study calculated an "optimum" temperature for each of 384 cities in the study. The optimum marked the temperature when deaths were least likely to occur and for each city was closer to the highest temperature than the lowest. Days were then labeled cold or hot depending on whether they were below or above that optimum temperature. Then the 2.5% of the coldest and hottest days in each city were used to define when temperatures were extreme. Each day's deaths were categorized as weather-related or not. Cold but not extremely cold days accounted for 6.7% of total deaths and extremely cold days accounted for another 0.6%. However, extreme cold was the cause of 10% of deaths on those days. Hot days accounted for only 0.4% of total deaths, but on extremely hot days, weather-related deaths were nearly 50% of the daily total. Because the study didn't include any nations in the Middle East or Africa, the result may not hold true everywhere, but having a better understanding of weather-related deaths overall may improve public health policies.
New Scientist: Many octopi have the ability to camouflage themselves by changing pigments in their skin. In one species, the ability has now been shown to be the result of light-sensitive cells in the octopus's skin. Desmond Ramirez and Todd Oakley of the University of California at Santa Barbara took samples of the skin of the California two-spot octopus and exposed them to light and within six second the brown spots the octopus uses for camouflage appeared. The pigment change is controlled by muscle cells that stretch sacs of pigment called chromatophores and is triggered by a protein called r-opsin that is also present in the octopus's eyes.
Science: After two years of Republican Party effort, the America COMPETES Act (HR 1806) has passed the House, with voting mostly along party lines. The goal of the bill is to define priorities for NSF, the Department of Energy, and the National Institute of Standards and Technology. The primary changes are to shift funds away from climate and geosciences research and to add restrictions to the way NSF makes grant application decisions. President Barack Obama has said that he will veto the bill as it currently stands, but it still needs Senate approval.
BBC: Before CERN's Large Hadron Collider (LHC) begins science-gathering collisions, workers there are testing its equipment, slowly ramping up the energy of its proton beams. Yesterday evening the collider reached an energy of 13 TeV at four collision points in the ring. During testing only a very few packets of protons are circulating at any one time. When the official "physics collisions" begin in June, several thousand packets will be in circulation simultaneously. The primary concern in the test collisions is determining whether the LHC systems can properly steer the protons at such high energies without damaging the machine or the detectors.
The Guardian: An international team of researchers led by geologist Sandy Cruden of Monash University in Melbourne, Australia, has identified a new mechanism by which ascending magma could trigger volcanic eruptions. The team made the discovery by simulating Earth's crust with a tank filled with two layers of pigskin gelatin of differing viscosity. Colored water was injected from below to mimic upwelling magma. When passing through the lower-viscosity layer at the bottom, the water flowed in a vertical column. But when it reached the high-viscosity layer, it spread horizontally to form what geologists call a sill. By suffusing the gelatin with fluorescent particles and illuminating it with a laser, the researchers found that the horizontal spreading lowered the pressure in the upper layer, causing the layer to sag. Some volcanic eruptions occur when a reduction in pressure causes one side of a volcano to collapse. Sill formation could be the trigger.