Physics Today Daily Edition

Subscribe to Physics Today Daily Edition feed
Please follow the links to view the content.
Updated: 5 hours 18 min ago

Jim Mitroy

18 February 2015

Targets of ARPA–E investment also receive private funds

18 February 2015

Nature: The Advanced Research Projects Agency–Energy (ARPA–E) was established seven years ago to help promote investment in clean-energy technology. On 9 February, at the program's annual summit, the project managers announced that technologies supported by ARPA–E have also received $850 million in private investment. The ARPA–E program itself has invested $1.1 billion in more than 400 projects, but determining the actual impact of the investment is difficult because of the slow-moving nature of the energy industry. However, over the past two years, venture-capital investment in the US has dropped sharply, with almost none going to early-stage clean-energy research. To help reverse that trend, the US government announced on 10 February a new initiative to increase private investment, which has already garnered a pledge of $1 billion from the University of California Board of Regents for investment in climate-friendly technologies.

Martian plumes remain a mystery

18 February 2015

New Scientist: Other than Earth, Mars is the most studied planet in the solar system. Nevertheless, mysterious phenomena continue to be observed there. On 12 March 2012 amateur astronomers saw what appeared to be a plume of gas and dust rising up to 250 km above Mars's surface. Over the next 11 days the plume grew to cover an area 1000 km across. By 2 April it had faded away. Just 4 days later a second plume appeared that lasted another 10 days. To date, no one has provided a satisfactory explanation of the plumes' origin. Agustin Sánchez-Lavega of the University of the Basque Country, Spain, and his colleagues have collected images of those events and searched archival images of Mars. Among the images, the researchers found a similar event from 1997. Because of the plumes' altitude and duration, they are unlike any other known clouds in the solar system. And as there are no known active volcanoes on Mars, they probably aren't volcanic plumes. Observing another such event may be the best option for figuring out what is going on, but they occur so rarely that it could be some time before that's possible.

Powerful x-ray source can image chemical reactions in real time

18 February 2015
BBC: Able to produce x-ray pulses a billion times as bright as any other existing source, the Linac Coherent Light Source at SLAC in California is capable of capturing images of the chemical reactions of atoms and molecules. The machine produces 100 pulses per second, and each is as powerful as “the national grid of a large country,” writes Pallab Ghosh for the BBC. The bright flashes of light allow scientists to take stop-motion pictures and perform stroboscopic experiments on materials at the nanoscale. That capability could prove revolutionary to the fields of biology and chemistry—for example, in studying neurological disease progression, such as in Parkinson’s, or in making chemical production faster and more efficient.

Limpet teeth surpass spider silk as strongest natural material, says study

18 February 2015
Telegraph: The tiny teeth that cover the tongues of limpets, a type of aquatic snail with a conical shell, are made of microfibers of goethite, an iron-based mineral. Used to scrape algae from rock surfaces, the teeth are superstrong and resilient. To test just how strong, researchers used focused ion beam microscopy to isolate a sample of the material and atomic force microscopy to test its tensile strength. According to their paper, published in the Royal Society journal Interface, they found that the material’s strength ranged from 3.0 gigapascals to 6.5 gigapascals—much stronger even than spider silk—and was independent of the sample’s size. The researchers say the material’s extreme thinness precludes the presence of holes or other flaws that could weaken the structure. The fibers are also tightly packed together. Such a strong, fibrous structure could have many uses, such as in cars, boats, and aircraft.

Questions and answers with Marcelo Gleiser

18 February 2015
A theoretical physicist argues that “science is a permanent work in progress” and that it is impossible to arrive at a final theory.

Metal nanoparticles give sticky tape new abilities

13 February 2015
New Scientist: A common roll of adhesive tape can acquire remarkable properties simply by having metal nanoparticles deposited on the film’s surface. The tape, which retains its stickiness after the deposition, exhibits new properties depending on the metal nanoparticles applied to its surface. Silver particles render it antibacterial, copper makes it antifungal, and gold increases its electrical conductivity. As described in a study published in the Journal of the American Chemical Society, a strip of tape is first peeled off the roll, which breaks the chemical bonds in the adhesive and readies it to react with the metal. Then it is soaked in a solution of metal salts. The technique could be used to create products such as antibacterial bandages or electrically conducting tape.

Controversy arises over recipient of Chinese science prize

13 February 2015

Nature: China's National Natural Science Award is so highly prized by Chinese government officials that they don't award it in years when they don't think a suitable recipient is available. Now, the computer scientist that received the award in January has been accused of copying open-source software and claiming it as original work. Zhang Yaoxue of Tsinghua University was awarded the prize for a computer program that allows access to multiple operating systems on a remote computer. But Chinese social media users soon pointed out that Zhang's work appeared to be heavily based on an open-source program available on the software sharing site GitHub. The author of that program, Iordan Iordanov, a Bulgarian-born Canadian, had posted his software under a license allowing anyone to use the program as long as they did not claim copyright. The Chinese government has acknowledged the allegations, but has not said whether they will have any effect on Zhang's award.

US likely to experience 20-year or longer droughts

13 February 2015

BBC: A new analysis of climate models by Ben Cook of NASA's Goddard Institute for Space Studies and his colleagues suggests that the US is likely to experience droughts on a scale unseen in nearly 1000 years. Cook's team combined reconstructions of past climate conditions and compared the data with 17 future climate models. According to their analysis, after 2050 the central and southwestern parts of the US will probably shift to conditions that will make them susceptible to decade-long droughts. The researchers also found that if current climate change rates are unchanged, there's an 85% chance that a 35-year-long drought will occur in those regions.

Computer program can authenticate Jackson Pollock paintings

13 February 2015
Ars Technica: American painter Jackson Pollock is well known for his revolutionary “drip” painting technique. Although to the untrained eye his works may look like random explosions of paint on canvas, a computer algorithm shows that his paintings have a distinctive and identifiable style. Lior Shamir of Lawrence Technological University has scanned various Pollock paintings and extracted from each 4024 “numerical image content descriptors,” including fractals, Zernike polynomials, Haralick textures, and Chebyshev statistics. A computer algorithm uses those descriptors to detect details and patterns unique to the artist in question. According to Shamir, whose study has been published in the International Journal of Arts and Technology, the computer program was able to differentiate between an original Pollock and a fake 93% of the time. Shamir’s source code is publicly available, and he says the software can be used to identify works of other artists.

Physics style

13 February 2015
An online collection of photos aims to dispel the prejudice that the physics community consists wholly of scruffy white men.

Court ruling: Journalists must not treat a scientist as “unavoidable road kill on the highway of public controversy”

13 February 2015
Canadian press reports success for climate researcher Andrew Weaver's libel suit—which calls to mind that of US climatologist Michael Mann.

Language used in UK research case studies reveals how words affect assessment scores

12 February 2015

Nature: Every few years the Higher Education Funding Council for England assesses the value of the research performed by the UK’s universities. The 2014 audit required that universities explain the impact of their research efforts through case studies that would account for 20% of their grade; the council received nearly 7000 of them. At the request of Nature, Paul Ginsparg of Cornell University performed a statistical analysis of the words used and found some predictable results, such as the frequent use of "research" and "impact." Other words used often were "development," "policy," and "health." Ginsparg noted a correlation between high assessment scores and the frequent use of words such as "million," "market," "government," "major," and "global." He also found a similar correlation between low scores and the repeated use of words such as "conference," "university," "academic," and "project." That could suggest that language used to show the research’s economic impact was more appealing to the graders.

New reactor design could make nuclear power cheaper, safer

12 February 2015
MIT Technology Review: A startup company, Transatomic Power, is developing a nuclear reactor that instead of using water as a coolant will use a new type of molten salt that will allow the reactor to burn its nuclear waste. Because the molten salt evaporates at a much higher temperature than water, it should also continue to cool the reactor even if the pumps fail, as happened at Fukushima in 2011. Additionally, the reactor will use zirconium hydride rather than graphite to keep the reactions going, since zirconium hydride is more resistant to radiation damage. The company says the reactor, which is based on a design developed at Oak Ridge National Laboratory in the 1960s, will be more compact and cheaper to build than current models. Transatomic is currently testing the design and hopes to have a demonstration model built by 2020.

Images reveal the formation of a multistar system

12 February 2015

Ars Technica: Many of the stars in the Milky Way coexist in binary, trinary, or larger systems. Despite the number of such systems, not much is known about their formation. New images of a star-forming area in the Perseus region have revealed the presence of a 0.1-solar-mass protostar surrounded by three other clusters of material, referred to as condensations, that are all likely to become protostars in the next 40 000 years. The condensations are connected to each other and to the protostar by filaments of gas that stretch across distances of up to 10 000 AU. Observations of the system revealed that the protostar and the condensations were barely moving relative to each other, which indicates that the regions are all gravitationally bound to each other. Whether the arrangement will actually evolve into a four-star system is not clear, but its existence supports the theory that gravitationally entangled stars can form from the same cloud of gas, rather than forming separately and only becoming entangled when they cross paths.

Carbon released from deep ocean led to end of Ice Age

12 February 2015
BBC: By studying the calcium carbonate shells left by marine organisms that lived thousands of years ago, researchers have been able to determine the acidity of the world’s oceans and, in turn, how much carbon dioxide they contained. They found that near the end of the last Ice Age, a reservoir of CO2 deep in the Southern Ocean was released into the atmosphere, which caused global temperatures to rise. Because Earth’s oceans currently absorb about 30% of anthropogenic fossil-fuel emissions, researchers say it’s important to understand the oceans’ role in the carbon cycle and how global warming could affect their ability to act as carbon sinks.

Predicting pentagonal graphene

12 February 2015
Calculations indicate that the carbon sheets are semiconducting and fairly robust.

High-speed cameras reveal secrets of popcorn's pop

11 February 2015

The Guardian: Researchers led by Emmanuel Virot of CNRS in Paris believe that they have an explanation for the popping sounds of popcorn. They combined high-speed cameras and audio recordings of popping kernels to show that the pop is not from the cracking of the kernel shells. Instead, the shape of the kernel serves as an acoustic resonator and causes the release of pressurized vapors to create the audible pop. A similar effect causes the pop of champagne corks. The team also found that the kernels pop when the vapor reaches 180 °C and that the "jump" of the pop occurs when starch in the kernel expands into the fluffy leaves that give popped corn its appearance.

European Space Agency launches mini-spaceplane

11 February 2015

BBC: Earlier today, the European Space Agency (ESA) launched the Intermediate Experimental Vehicle (IXV) atop a Vega rocket from French Guiana. The IXV will reach an altitude of 450 km before descending. The primary mission is a test of re-entry control systems on the wedge-shaped vehicle. The ESA has limited experience with returning vehicles to Earth and hopes to incorporate the knowledge gained from the launch into future craft.

Current geoengineering schemes likely ineffective

11 February 2015

Nature: A report by the US National Research Council (NRC) says that none of the plans put forward to reduce atmospheric carbon dioxide through geoengineering are likely to be effective. The report provides an official stance for the government regarding a field that the NRC calls "climate intervention" because other names imply a level of knowledge and ability that does not exist. Several proposed plans to change the atmosphere's reflectivity to directly alter Earth's climate were rejected as too risky; information about the full effects of such plans is lacking. In contrast, plans for carbon capture and storage were considered not particularly risky. However, the report considers the technology to be too new, expensive, inefficient, and damaging to the environment in other ways to be truly effective at reducing CO2 levels significantly in the near term.

Pages