Physics Today Daily Edition
New Scientist: Climate change is becoming an ever-more pressing issue. According to the latest report by the Intergovernmental Panel on Climate Change, the only way to avoid “severe, widespread, and irreversible impacts globally” is to immediately curb carbon dioxide emissions and phase them out almost entirely by 2100 or, at the very least, develop technologies to safely bury them underground, a method called carbon capture and storage. Although a potentially cheaper and easier alternative had been proposed—to reduce other greenhouse gas emissions—a new study shows that the benefits of such a plan have been overestimated, for two reasons. Other greenhouse gases, such as methane, do not accumulate in the atmosphere the way CO2 does. And they tend to be emitted by the same sources as CO2 emissions, such as the burning of fossil fuels. "Science has spoken,” said United Nations secretary general Ban Ki-moon. “Leaders must act. Time is not on our side.”
BBC: Although landscape and diet have been well researched for most animals in zoos and other types of wildlife centers, noise levels have not. And for some animals, such as the rhinoceros, which can hear sounds at much lower frequencies than humans can, the chronic infrasound of urban environments may be affecting captive animals’ behavior, particularly their breeding and reproduction rates. At the fall meeting of the Acoustical Society of America, Suzi Wiseman of Texas State University and colleagues presented their findings regarding the varying soundscapes of zoos. The researchers have been studying various facilities, both those where rhinos breed well and those where they do not, in order to devise a system of acoustic parameters to improve rhino habitats. They hope their findings will benefit not only endangered species but all animals, wild and domestic, that are experiencing human encroachment.
Ars Technica: Planet formation is complicated in a single-star system and is even more so in systems with two or more stars. It is thought that in multistar systems, each star will have its own protoplanetary disk of dust, and a larger disk will surround the system. GG Tau A is a trinary system 460 light-years away, and recent observations have revealed some details about how such systems work. Emmanuel Di Folco of the University of Bordeaux in France and his colleagues used the Atacama Large Millimeter/Submillimeter Array (ALMA) to study the system. The primary star in the system, GG Tau Aa, has a disk, while the pair of secondary stars GG Tau Ab1 and GG Tau Ab2 (which orbit each other 35 AU from GG Tau Aa) were not seen to have disks, although previous IR observations suggested they might. ALMA also showed evidence of a larger disk surrounding the system. More importantly, ALMA revealed a flow of material from the outer disk to the disk around GG Tau Aa. Without that transfer of material, the internal disk would likely have fallen apart due to the stars' gravity, long before any planets could have formed. ALMA did not reveal any planets around the three stars, but the images did suggest that a planet may be forming in the surrounding disk. The presence of a protoplanet there could explain why the disk is relatively narrow, with 80% of its mass in a region just 90 AU wide.
Science: China’s proposed KuaFu solar wind observatory has been put on hold indefinitely due to loss of funding and support from its international partners. Both the European Space Agency and the Canadian Space Agency had been collaborating with the Chinese Academy of Sciences (CAS) on the mission to put three satellites in orbit to forecast space weather. Although China has successfully launched more than 100 satellites, KuaFu would have been only the second dedicated to science research. Despite attempts to scale the project down to a single satellite, the CAS has also withdrawn its support in light of the fact that KuaFu is no longer a major international collaboration.
MIT Technology Review: The likelihood that a photon will be absorbed as it travels through fiber-optic cables increases with distance, so repeater systems positioned at regular intervals about 100 km apart are needed for maintaining the signals. Such a system works well for conventional communications. However, transmitting quantum information via entangled photons is much more difficult. Quantum repeaters are hard to maintain, especially on undersea cables, because they must be kept at near absolute zero temperatures. Kristine Boone of the University of Calgary in Canada and her colleagues suggest instead using a small network of satellites whose primary functionality would be producing entangled photon pairs. Those photons would then be sent to separate ground stations where they would entangle the quantum data stored in those stations. The entanglement would then be used to securely transmit the data.
Science: Weakly interacting massive particles (WIMPs) are a hypothesized form of dark matter. According to the model that describes WIMPs, large numbers of the dark-matter particles formed in the early universe. When they interacted with each other, they decayed into normal particles. As the universe expanded, such interactions became rarer, leaving enough WIMPs in proportion to ordinary matter to fit astrophysical observations. Because no WIMPs have yet been directly detected, however, alternative theories have been proposed, including the existence of strongly interacting massive particles (SIMPs). In a new paper, Yonit Hochberg of Lawrence Berkeley National Laboratory and her colleagues argue that the production and elimination of SIMPs could have followed a similar pattern as that proposed for WIMPs. And because SIMPs are more likely to interact with regular matter, they should be easier to detect.
BBC: The French government is looking into the origin of several small, unmanned aircraft that were seen flying over 7 of France’s 19 nuclear facilities over the past month. According to French law, no aircraft is allowed to fly below 1000 m within 5 km of a nuclear plant. The first drone was observed on 5 October near the Creys-Malville plant in the southeastern part of the country, and four different drones were observed on 19 October hovering over plants in four different regions of the country. Although Greenpeace was initially suspected, the group has denied responsibility. Because of the aircraft’s small size, it is believed to be unlikely that they could cause any serious damage.
New Scientist: Humans can be acutely sensitive to certain odors, particularly those perceived to be unpleasant. Now a pair of researchers has developed a mathematical model to rate smells on a numerical scale based on their physical and chemical properties. Canceling out a particular smell requires a compound of equal and opposite rating, such that the two combined yield a zero score overall. Thus, rather than try to mask an existing smell with one that is more powerful, they propose creating the olfactory equivalent of white noise. According to their simulations, eliminating the notoriously pungent odor of an onion, for example, would require a blend of 38 different compounds. Next they plan to work on a device that would put the theory to the test.
BBC: The ability to control vocal frequency and to apply other effects determined by cultural influences appears to be the technique used by the most effective speakers. In a new study, UCLA's Rosario Signorello and colleagues modified the vocal frequencies of recorded speeches from several male politicians. They asked 250 volunteers to categorize the speeches by choosing from 67 adjectives, such as attractive, convincing, dishonest, dynamic, fair, and scary. The volunteers were also asked which voices they preferred. The researchers found that the best speakers were able to adjust their voices to convey a range of different characteristics as needed. The ability to reach deeper tones, which can be considered authoritative or sexy, is partially inherent in speakers with larger voice boxes and vocal folds. But much of what determined charisma depended on the audience: French listeners preferred moderate frequencies, which they said sounded prudent and fair, while Italian listeners preferred lower-pitched voices, which they perceived as authoritarian and menacing.
Ars Technica: One reason life developed on Earth may be the planet's abundance of nitrogen, an essential ingredient for the formation of amino and nucleic acids. About four-fifths of Earth’s atmosphere is composed of nitrogen. Until recently, however, exactly where the nitrogen came from was unknown. Now Sami Mikhail and Dimitri Sverjensky of the Carnegie Institution of Washington propose that Earth’s plate tectonics are responsible. Nitrogen is easily incorporated into silicate minerals, not only on Earth but also on other planets, such as Earth’s nearest neighbors, Venus and Mars. Unlike those neighbors, however, Earth is geologically active, and the combination of plate subduction and volcanic eruptions results in the release of copious amounts of volatile chemicals, including nitrogen, into the atmosphere. According to the researchers' findings, nitrogen started accumulating in Earth’s atmosphere some 3 billion years ago, which agrees with other estimates for how long Earth’s plate tectonic system has been active.