Physics Today’s online staff summarize the most important and interesting news about science from the world's top media outlets.
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.
Nature: In response to global warming, the Heat Wave Magnitude Index (HWMI) has been devised to provide a way to compare the severity of heat waves around the world and over time. Similar to the Richter scale for comparing the magnitude of earthquakes, the HWMI is designed to be more comprehensive than previous systems by taking into account heat intensity and duration in different regions and in different years. According to the new scale, the worst heat wave to date occurred in Russia during the summer of 2010 when 55 000 people died. The HWMI also predicts that the number and size of heat waves will continue to increase throughout the 21st century, a prediction consistent with earlier research.
Science: The Tuesday evening launch of an unmanned Antares rocket from Wallops Flight Facility in Virginia ended abruptly with an explosion six seconds after liftoff. The rocket, built by Orbital Sciences Corp, was headed to the International Space Station with 748 kg of supplies and 727 kg of scientific experiments. Many of the projects lost were designed by students. One, from the Duchesne Academy of the Sacred Heart—an all-girl college preparatory school in Houston, Texas—was to investigate how well fast-growing plants, such as pea shoots, do in microgravity and when exposed to red and blue wavelengths of light. Despite the sad outcome, school administrators emphasized the importance of the experience gained in participating in the program and creating the experiments.
Nature: On 29 August, the Icelandic volcano Bárðarbunga began erupting in a steady flow of lava that has not stopped. It has produced more lava than any Icelandic eruption since 1947, but the amount of sulfur dioxide it has released is far beyond any predictions. Nearly 35 000 tons of SO2 is being released daily, twice as much as produced by all European industries combined. The high levels have caused breathing problems for nearby residents and have elevated pollution readings all the way into central Europe. The Icelandic Meteorological Office is attempting to track and provide warnings about the gas cloud's movement. However, the volcano's remote location and the onset of winter are making it hard to closely monitor the eruption. The timing of the eruption was good because it began in the middle of FUTUREVOLC, an ongoing study of vulcanism and the movement of magma.
Science: In 2029, a football-field-sized asteroid known as Apophis is going to pass within 35 000 km of Earth. Our planet is not in any danger, but simulations run by Derek Richardson of the University of Maryland, College Park, and his colleagues suggest that Apophis could experience avalanches, albeit very small ones. Pictures of another asteroid believed to be similar to Apophis indicate that instead being solid rock, the two asteroids are clumps of debris loosely held together by gravity. In Richardson's simulation, the tidal force of Earth's gravity caused small, slow-moving avalanches of the lighter pieces of debris on the asteroid's surface. Although astronomers will not be able to see the avalanches directly, IR pictures of the surface could reveal areas that have been uncovered as the surface shifts.
New Scientist: Astronomers continue to be surprised by Saturn’s moon Enceladus. Most of the planets and moons studied so far consist of a core of dense material covered by a large mantle and an outer crust. Based on computer modeling, however, Enceladus’s core can’t be stiff and rocky and also produce the huge watery plumes that have been observed shooting into space as the moon orbits Saturn. In order to generate the heat necessary to melt the icy crust and shoot the jets, the moon’s core may be more like a rubble pile with empty spaces filled with ice or water, similar to a snow cone. The finding has implications for the search for extraterrestrial life because such hydrothermal systems are important to the formation of biological organisms.
Globe and Mail: People may one day pop a pill filled with magnetized nanoparticles that will circulate through the body looking for signs of cancer. That is one of many projects being developed by Google X, a facility dedicated to exploring innovative technologies, such as the self-driving car. The cancer-detecting nanoparticles would be coated with antibodies that bind with abnormal cells. A device worn by the patient would then recall the nanoparticles and download the data they’ve gathered. Such technology could monitor an individual’s health 24/7, deliver medicine to localized areas, and detect other problems as well, such as arterial plaques. So far, the project is only in the exploratory phase.
MIT Technology Review: A quantum version of the internet is being envisioned to securely transmit information. Because such a network would use entangled photons to transfer data, it would avoid the potential interference or hijacking of information that can occur during transmission through optical fibers or other conventional media. However, quantum networks will still encounter some of the same logistical problems, such as how to relay information across the oceans. Whereas quantum repeaters can extend the range of entanglement, they have been shown to work only over short distances and may prove too delicate to withstand the hostile conditions at the bottom of the sea. Now Simon Devitt from Ochanomizu University in Japan and colleagues have proposed that the quantum bits of information, or qubits, be transported across the water via container ship. Unlike conventional photons, the qubits would carry entanglement rather than actual information. Once they were in position, communication between them would be even faster than traditional repeater networks.
New Scientist: Two previous detections of gamma rays from the center of the Milky Way have been cited as evidence of the annihilation of dark-matter particles. Now astronomers have spotted a third gamma-ray source that matches the predictions of dark-matter annihilation as well. Kevork Abazajian of the University of California, Irvine, and his colleagues predicted that starlight passing through the center of the Milky Way would scatter in a particular way off electrons produced by the annihilations. They found evidence of just such a signal in data collected by the Fermi Gamma-Ray Space Telescope and all-sky starlight surveys. However, proving that the electrons that cause the scattering came from dark-matter annihilation is a more difficult task.
Guardian: For the first time, astronomers have captured images of a nova, a nuclear explosion on a white dwarf star. Nova Delphini 2013 was first detected last year by the CHARA Array IR telescope at Mount Wilson Observatory in Los Angeles. Such explosions are believed to occur in binary star systems, when a white dwarf is able to accrete enough hydrogen from its companion star that it ignites and starts nuclear fusion. Within hours of the explosion, astronomers were able to point the array telescopes toward the nova to take interferometric measurements of its size and expansion rate. From that data, they have determined that the nova is about 14 800 light-years from the Sun, which means the explosion occurred some 15 000 years ago. When last measured 43 days after the explosion, the nova had expanded nearly 20-fold.
BBC: The UK's Met Office has confirmed that it will build a £97 million ($156 million) supercomputer to replace the one it currently uses for weather and climate modeling. The computing facility's location will be split between the Met Office's headquarters and a new facility, both in Exeter. The first computations will take place in September 2015. The Cray XC40 will have a processor speed of 16 petaflops (16 × 1015 calculations per second), 13 times faster than the current machine, and will have 17 petabytes of storage. That will allow for faster and more accurate weather forecasts as well as better and longer-scale climate models. Because of the UK's location and geography, weather forecasting is more difficult than in many other places. The Met Office estimates that improved forecasts could provide £2 billion in economic benefits.
Ars Technica: According to the US Energy Information Administration (EIA), total US emissions of carbon dioxide rose in 2013 compared with the previous year. The rise constitutes an upward blip in a downward trend that began nine years ago. Increased economic activity was not responsible for the rise, says the EIA. Although US GDP per capita rose by 1.5% from 2012 to 2013, the gain was partly offset by increased energy efficiency. Rather, the boost in emissions resulted primarily from the unusually low temperatures of last winter, which led to increased burning of fuel oil. Another contributor was a rise in the price of natural gas, which prompted electric utilities to save money by burning more coal.
MIT Technology Review: Ferroelectric materials can be made to reverse the direction of their polarization by applying an electric field. Once changed, the direction of the polarization persists, a property that has been exploited to store data. But until now, the speed at which the change occurs has been too low to rival the switching speeds attained by silicon-based transistors. A collaboration led by Lane Martin of the University of California, Berkeley, and Andrew Rappe of the University of Pennsylvania has developed a ferroelectric material, lead zirconate titanate (PbZr0.2Ti0.8O3), that can switch much faster than standard ferroelectrics. The key to the gain in speed lies in growing crystals of the material at a particular orientation, which creates two so-called side states of polarization in addition to the regular two states. The faster-switching side states can be manipulated by applying an electric field in a particular direction.
Science: Creation Summit, a nonprofit Christian group that believes in a literal interpretation of the Bible, will hold its Origins Summit on 1 November at Michigan State University. The conference venue was booked through a campus student group. Among the sessions listed in the summit's program are ones devoted to why the Big Bang is fake, how evolutionary theory shaped Adolf Hitler's worldview, and why natural selection is not evolution. Michigan State is the academic home of several prominent evolutionary biologists, including Robert Pennock, whose testimony played a role in Kitzmiller v. Dover Area School District, a 2005 case that led to a ban on teaching intelligent design in public schools. Citing the right to free speech, university authorities have said they do not intend to interfere with the summit.
New Scientist: Today, if all goes to plan, a cookie-jar-sized space telescope called Arkyd 3 will hitch a ride to space on Orbital Sciences' next commercial mission to resupply the International Space Station. Built by Planetary Resources, the telescope is a test bed for technology for identifying asteroids whose metal content could be profitably mined. Ultimately, Planetary Resources, which is backed by movie director James Cameron, X-Prize founder Peter Diamandis, and Google executive chairman Eric Schmidt, plans to launch 10 space telescopes.