Physics Today Daily Edition
MIT Technology Review: As reported earlier this year, the first commercial-scale system for carbon capture and storage has begun operation at a coal power plant in Saskatchewan, Canada. The 110-MW power plant has been retrofitted to capture 90% of its carbon dioxide emissions. It then pumps the CO2 into nearby oil fields to help extract the oil and, at the same time, store the gas in the rock underground. Even with the 90% reduction in emissions, however, the plant still produces the same amount of carbon pollution as a natural gas plant—roughly 150 tons of CO2 per gigawatt-hour.
MIT Technology Review: Francis Collins, director of the US National Institutes of Health, announced earlier this week that the agency would be distributing $46 million in research awards as part of the Brain Research through Advancing Innovative Neurotechnologies (BRAIN) initiative. The funds will be distributed to 58 research groups working on projects that include a wearable PET scanner, laser control of neuron activity, and electrodes that can detect the presence of dopamine in living brains. One of BRAIN's goals is to develop technologies for better understanding how the brain operates. Because of the complexity of the brain, many researchers think that the technology needed to make immediately useful discoveries does not yet exist. The initial investment by BRAIN may help rectify that situation.
Nature: Over the past two years, a cloud has been forming over the south pole of Titan, the largest of Saturn’s moons. The discovery was not unexpected, as the southern hemisphere has been shifting to winter, and a cloud had appeared over the north pole a decade earlier when the northern hemisphere was experiencing winter. However, data from NASA’s Cassini spacecraft indicate that the cloud is much higher, at 300 km, than expected. It is also composed of micrometer-sized particles of hydrogen cyanide ice, indicating that the air temperature is at least 100 K colder than predicted. Because the cloud only appeared two years ago, and there was no indication of cyanide ice at that time, the atmospheric temperature must be dropping relatively rapidly. The surprising findings indicate that Titan may be more dynamic than researchers thought and that global-circulation models of Titan’s atmosphere may need to be revised.
BBC: Until 2012, when NASA’s GRAIL mission mapped the Moon’s gravity gradients, it was assumed that the Procellarum—a large lunar mare on the Moon’s near side—had been formed as the result of an ancient giant impact with a smaller celestial body. However, by looking more closely at variations in the pull of gravity over the Moon’s surface, researchers were able to detect an excess of mass that they attributed to the presence of basaltic lava filling rift valleys. Because of the presence of large amounts of uranium, thorium, and potassium in the Procellarum region, they propose that early in the Moon’s existence those radioactive elements would have caused the crust to heat up and expand. Subsequent cooling would have then caused the surface to contract and led to the creation of large rifts, which later were filled in by volcanic lava. The theory would explain the Procellarum’s distinct rectangular shape, as opposed to the more circular shapes of other lunar maria.
Science: Although prolonged exposure to loud noises has long been known to lead to hearing loss, a new study shows that low-frequency sounds may also cause damage. Neurobiologists at the Ludwig-Maximilians University in Munich exposed 21 volunteers to a deep, vibrating noise in the 30-Hz range—barely audible to the human ear. Such noise levels are regularly generated by wind turbines, roaring crowds, and jet engines. Then the researchers measured the spontaneous otoacoustic emissions (SOAEs) produced by the participants’ inner ears. Healthy ears regularly emit SOAEs; damaged ears do not. The researchers found that just 90 seconds of exposure to low-frequency sound caused participants’ SOAEs to start oscillating erratically. Although that is not proof that such sounds can cause permanent damage, the effect may leave the ear temporarily more prone to damage, they say.
Nature: The Tibetan Plateau is 2.5 million km2 in area and has an average elevation of more than 4 km. However, because of its remote location, its effect on local weather and global climate is poorly understood. Now, the China Meteorological Administration and the National Natural Science Foundation of China are working together to install a variety of sensors to monitor local weather conditions throughout the plateau. The $49 million project includes soil temperature and moisture detectors, 32-m-tall towers to measure cloud properties, weather balloons, and remote-controlled drones. The plateau is the site of the third largest concentration of ice after the poles but also has a diverse mix of landscapes, including deserts, forests, grasslands, and farmland. Because of its altitude, it receives more sunlight and heats up more than similar expanses of land at lower levels. The resulting heating effect is believed to amplify the strength of monsoons in southern Asia.
New Scientist: On 29 July astronomers discovered a small asteroid that appears to be orbiting Earth but is really orbiting the Sun. Called 2014 OL339, it is the fourth such near-Earth quasi satellite discovered so far. For some 775 years, the asteroid has been circling the Sun in resonance with Earth, whose gravity shapes its eccentric orbit. But astronomers say that will probably only last another 165 years or so. Although the Moon is the only true Earth satellite, many different types of space rocks are drawn into temporary orbit by Earth’s gravitational pull and hang out for various periods of time, ranging from months to years.
BBC: On 16 September, NASA announced that it had selected Boeing and SpaceX to receive contracts for the development of manned space capsules. One of the companies that did not receive a contract, Sierra Nevada Corporation (SNC), has now filed a protest that will delay the awarding of the contract money to both Boeing and SpaceX. The basis of SNC's protest is that its proposal was $900 million less expensive than Boeing's. The company cited "serious questions and inconsistencies in the source selection process" and requests another review of the proposals. NASA has 30 days to respond to the protest, and the Government Accountability Office is expected to rule on the protest in January 2015.
BBC: The Mars Curiosity rover, which has been exploring Gale Crater since it landed there in 2012, just drilled another hole into Martian rock. Although the rover has drilled several holes so far, its main target is Aeolis Mons, also called Mount Sharp, a tall mountain located at the center of the wide crater, toward which the rover has been traveling since it landed. Because of the enormous mound of sedimentary debris lying at the mountain’s base, researchers targeted the area for geological study. They hope that samples collected by Curiosity as it climbs up Mount Sharp will yield progressively younger sediments and, hence, clues to Mars’s geologic past. Earlier samples taken by Curiosity showed a high silica content and other evidence indicating that Mars may have had vast amounts of liquid water on its surface billions of years ago.
Ars Technica: Water vapor has been detected in the atmosphere of HAT-P-11b, an exoplanet about the size of Neptune. Until now, such detection had only been possible in the atmospheres of Jupiter-sized planets. The discovery was made from studying spectrographic data gathered by three spacecraft—the Hubble Space Telescope, the Spitzer Space Telescope, and Kepler. The lack of cloud cover around HAT-P-11b is what allowed researchers to study the spectrum of light that traveled through the planet’s atmosphere as it passed in front of its host star. Because different types of molecules absorb different wavelengths of light, the researchers were able to detect the presence of not only water vapor in the planet’s atmosphere but also hydrogen and small amounts of heavier elements. The ability to determine planets’ atmospheres, in addition to their mass and radii, could provide key insights into planetary formation and evolution. As higher-precision instruments, such as the James Webb Space Telescope, are developed, astronomers hope to be able to detect much fainter signals and even smaller planets.