Physics Today Daily Edition
New York Times: Getting the last of anything out of a bottle usually involves scraping the inside. Depending on the viscosity of the substance, up to a quarter of the contents of a bottle may end up being thrown out. Now, Kripa K. Varanasi of MIT and graduate student J. David Smith have created a startup, called LiquiGlide, to market a coating they developed that allows a bottle's contents to easily slide out, regardless of the viscosity. Thanks to its porous surface, their material traps a lubricant that can be customized to best match the properties of the intended contents of the bottle. The lubricant makes the inner surface of the container superhydrophobic, which prevents the contents from binding to the container's interior.
New Scientist: Last week's solar eclipse was visible across much of Europe. That meant that the solar generating capacity of many countries was reduced briefly and other energy sources needed to be deployed. Since 2006, the European Union has spent €3 billion ($3.28 billion) on developing smart-grid technologies to help balance the distribution of energy in response to fluctuations in demand or production. In Germany, for instance, which gets 26% of its power from solar and wind, last week's eclipse provided an important test of the grid's ability to handle sudden changes. To be on the safe side, the country doubled its network staff for the day and also turned off four aluminum plants that draw a lot of power. During the eclipse, Germany's solar energy production dropped from 38.2 GW to 23.2 GW. No problems were reported, however, in either Germany or any of the countries that contribute the other 51 GW of solar power in the EU.
Science: At the Lunar and Planetary Science Conference this week, an unexpected finding about the location of the Moon's ice was announced. Unlike the ice found on most planetary bodies in the solar system, the Moon's ice does not cover its north and south poles, but rather is located several degrees away from its poles. Matthew Siegler of the Planetary Science Institute in Dallas, Texas, and his colleagues reexamined data collected by the Lunar Prospector mission, which orbited the Moon 16 years ago. They realized that the two patches of lunar ice were directly opposite each other. The most likely explanation for this arrangement is that the ice was originally deposited at the lunar poles, and at some point, the Moon's axis must have shifted by more than 5°. None of the known asteroid impacts are large enough or in the right location to have been the cause. Siegler's team believes the outpouring of lava that created the Oceanus Procellarum some 3.5 billion years ago could have unbalanced the axis.
Nature: On 16 March, the European Space Agency (ESA) and the Chinese Academy of Sciences closed a call for proposals for a joint space mission. The ESA has contributed instruments to a Chinese satellite before, but this will be the first mission to be a collaboration from the start. The two agencies are each contributing the equivalent of just over $53 million to the project, a funding amount that limits its size. Another limitation is that the mission should focus on something other than Mars or the Moon, which are already being studied through other projects. The agencies received 16 proposals, which included studying radio signals, x-ray imaging of Earth's magnetosphere, and looking at "hot objects" with an extreme-UV telescope. The proposals will be examined based on technological feasibility and scientific merit. By the end of the year, the best will be selected to undergo further review, with a final decision to be made in 2017.
Ars Technica: Last week, it was announced that several new dwarf galaxies surrounding the Milky Way had been found. Now, a team led by Alex Geringer-Sameth of Carnegie Mellon University has found that the closest of those galaxies, Reticulum 2, emits gamma rays. The finding is notable because dwarf galaxies generally lack the usual objects, such as black holes and pulsars, that produce gamma rays. And no previous dwarf galaxy has ever been found emitting gamma rays. The signal from Reticulum 2 could be detectable simply because it is the closest dwarf galaxy yet found. Because dwarf galaxies have a high concentration of dark matter, they are believed to be good candidates for study to try to find out what kind of particles dark matter is made of. Geringer-Sameth's team believes that the gamma-ray signal could be evidence of self-interacting dark-matter particles, such as WIMPs, colliding with each other. However, there are still too many characteristics of Reticulum 2 that need to be clarified before that theory can be confirmed.