Physics Today Daily Edition
New Scientist: If you take a strip of paper and give it a half twist and tape the ends together, the result is the one-sided loop known as a Möbius strip. Now, Peter Banzer of the Max Planck Institute for the Science of Light in Erlangen, Germany, and his colleagues have demonstrated a similar effect using light. In 2005 it was predicted that light's polarization could become twisted like a Möbius strip. Banzer and his team achieved the effect by scattering two polarized beams off gold nanoparticles in such a way that the beams interfered with each other. The resulting light had polarizations with either three or five twists. The ability to twist polarized light could reveal details about light's 3D structure, which could lead to uses in biomedical imaging and particle manipulation.
Nature: On 29 January, the Nuclear Regulatory Commission (NRC) released the final two volumes of its technical analysis of the Department of Energy's proposal to use Yucca Mountain in Nevada as a nuclear waste repository. Although the report indicates that DOE's plan is sound, the NRC does not recommend going ahead with the construction. President Obama abandoned the project five years ago. Yet a federal court ruled that the NRC had to continue the study while it still had funds to do so. Even if Congress were to provide more funding for the next step (a further analysis of ecological impacts), the local governments in Nevada are openly resistant to selling the land to the federal government. Without that land, construction cannot begin.
Science: John Culberson (R-TX) is the new chair of the Commerce, Justice, Science (CJS), and Related Agencies spending panel in the US House of Representatives. CJS oversees a large portion of US science research spending, including the funding for NASA, NIST, NSF, and the National Oceanic and Atmospheric Administration. Culberson says that he has had a lifelong passion for science despite his chosen career in law. He also says his desire to support government investment in science does not contravene his fiscal conservatism. However, that support seems to be limited to space science and basic research and does not include the social and behavioral sciences. He says he supports fellow Texas representative Lamar Smith's efforts to focus NSF's research grants on basic science.
Ars Technica: Nitrogen composes about 78% of Earth's atmosphere and is the most common pure element on the planet. However, the nitrogen on Earth does not occur in the same isotope fractions as the nitrogen found in the Sun or in the tails of comets. A new analysis of an ancient meteorite may provide some clues as to where Earth's nitrogen came from. Transmission electron microscopy and secondary ion mass spectrometry reveal that the meteorite contains the mineral carlsbergite. The mineral's characteristics suggest it was formed in the presence of ammonia (NH4), which likely came from ice in the Sun's protoplanetary disk. That ice could later have been part of the material that accreted to form Earth. It is possible that the different isotope ratios of nitrogen found in the Sun and in comets blended in such a way as to produce the nitrogen mix now present on Earth.
MIT Technology Review: Lithium-air batteries have a theoretical energy density 10 times that of current lithium-ion batteries. In a car, they would provide energy comparable to that of a full tank of gas. However, current models are still far from reaching that energy density, and the number of times they can be recharged is limited. Lithium-air batteries work by allowing lithium ions to react with the oxygen in air to create lithium oxide. Recharging them involves breaking back down that molecule. The batteries' ability to be recharged is limited because the lithium oxide tends to bond to one of the battery's electrodes, covering the catalyst that facilitates the breakdown of the lithium oxide. A team of researchers from Yale and MIT has developed a new membrane made of catalyst-coated nanofibers to which the lithium oxide doesn't bond. The extra catalyst increases the battery's energy density and doubles the number of recharge cycles. However, the experimental battery can be recharged only about 60 times before it needs to be replaced. Commercial car batteries should be able to be recharged roughly 1000 times. The battery also uses pure oxygen instead of air because air's carbon dioxide reduces the battery's efficiency.
Nature: Scheduled for launch on 29 January, NASA's Soil Moisture Active Passive satellite will use microwave signals to measure soil-moisture levels everywhere on Earth and to determine whether the soil is frozen. Clear measurements of soil moisture will help improve water availability models, which are important for both urban and rural areas. The data will help insurance companies to improve crop price models and allow scientists to better monitor droughts and other climate trends. The information on frozen and thawed soil can be used by the military for planning troop movements and by scientists for measuring polar melt due to climate change.