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Physics Today’s online staff summarize the most important and interesting news about science from the world's top media outlets.

August 29, 2014 4:00 PM

TNT-covered carbon nanotube fibers generate electricity when burned

MIT Technology Review: Four years ago, Michael Strano of MIT and his colleagues created yarn out of carbon nanotubes that were covered in TNT. When ignited with a laser, the fibers burned like fuses, but with the curious effect of generating an electrical current. Strano's team has now discovered that the combustion creates a wave of electrons that travels down the fiber. Thanks to the discovery, they could increase the yarn's electricity-generating efficiency by a factor of 10 000, with the potential for further increases. The actual efficiency is still very low compared with that of traditional combustion generators, but Strano believes the material could find use in applications that need short bursts of electricity. With further advances, large versions of the generators could be used to power electric motors with liquid fuels.
August 29, 2014 1:14 PM

Theory of origin for Type Ia supernovae gains direct evidence

BBCType Ia supernovae have long been thought to be caused when a white dwarf gains enough mass to push it over the Chandrasekhar limit. White dwarfs are the remains of stars that have burned through most of their light elements and have a core of carbon and oxygen that is no longer undergoing fusion. If they steal enough material from a companion star, or merge with another white dwarf, the extra mass compresses the core and causes the heavier elements there to fuse. The sudden release of energy causes the star to explode into a supernova. Although the theory has been widely accepted for decades, a supernova detected on 21 January 2014 has provided the first confirmation that a white dwarf is the source of type Ia supernovae. When a white dwarf’s carbon and oxygen fuse, they create a radioactive isotope of nickel that decays into radioactive cobalt that then decays to stable iron. Observations of the supernova using the European Space Agency’s INTEGRAL spacecraft revealed the signature gamma-ray emissions associated with the cobalt isotope’s decay. The emissions also closely matched the model of a white dwarf explosion. However, there is still not enough information to determine whether it was a white dwarf drawing material from a companion or a collision of two white dwarfs that caused the supernova.

August 29, 2014 12:50 PM

Fermilab builds holometer to look for jitter in spacetime

New Scientist: To probe space and time at the very smallest scales, researchers at Fermilab have built a holographic interferometer, or holometer. At the quantum level, matter and energy behave more like waves than particles. The researchers propose that a similar concept may apply to space and time. Their device consists of two 40-meter-long tubes fitted with mirrors through which they shine powerful lasers. If both sets of mirrors are seen to change position as much as a billionth of a billionth of a meter, it could indicate the existence of fluctuations in the fabric of space. If such a spacetime jitter exists, it would present another explanation of why the universe is accelerating besides the current one involving dark energy.

August 29, 2014 12:25 PM

Death Valley’s rocks “wander” due to ice shove

Nature: For the first time, the so-called sliding rocks of California’s Death Valley National Park have been recorded in motion. For more than half a century people have noticed that stones on the flat desert lake bed of Racetrack Playa appear to have moved because of the long trails they’ve left behind them in the ground. But no one had ever observed the rocks moving. Now Richard Norris of the Scripps Institution of Oceanography in La Jolla, California, and colleagues have used time-lapse photography and rocks instrumented with GPS trackers to record their movements. In their paper published in the journal PLOS ONE, the researchers report that the rocks' motion cannot be blamed on thick ice and strong winds. Actually, windowpane-thin ice sheets melt, break into pieces, and push the rocks slowly along paths determined by the direction and velocity of the wind and of the water flowing under the ice.

August 28, 2014 4:50 PM

Entangled photons create images of things they never interacted with

Science: A quirk of quantum entanglement allowed researchers to create images of target objects using photons that never interacted with the object. Using the technique, Anton Zeilinger of the Austrian Academy of Sciences in Vienna and his colleagues created images of cats that had been cut out of thin slices of silicon. The process starts with two pairs of entangled photons. One of the photons in the first pair is sent through the target object and one of the second pair is sent past it. They are then allowed to interfere with each other. The interference is passed to the second pair of entangled partners, which are sent to a camera to build an image of the target object. To ensure that the effect was real, Zeilinger’s group sent photons with wavelengths the camera couldn’t see toward the target and entangled them with photons that the camera could see. The result was two images showing either the outline of the object or showing the object directly, depending on whether the photon detected was entangled with the photon that went through or past the target.

August 28, 2014 3:35 PM

Earthquakes continue around Icelandic volcano

BBC: Although Iceland’s Bardarbunga volcano has yet to erupt above ground, it continues to worry scientists. A spate of earthquake activity in mid August had put Iceland’s Meteorological Office on high alert. Then earlier this week the subglacial volcano began to erupt. Since Monday a huge subterranean channel of molten rock has been traveling north from Bardarbunga toward another volcano, Askja. As the magma moves, it cracks the rocky ground and has set off numerous earthquakes over a distance of some 40 km. Scientists are concerned that because the magma is moving at a rate of about 4 km/day, it could eventually reach the Askja volcano and trigger a large eruption there. But volcanoes are hard to predict; the magma channel could follow any number of underground fissures and completely bypass Askja, or it could freeze deep underground and stop moving altogether.

August 28, 2014 1:10 PM

Low-energy neutrinos provide direct evidence of solar proton–proton reactions

Nature: Proton–proton reactions are the first step in the hydrogen fusion process that powers the Sun and 90% of the other stars in the Milky Way. In the process, two protons are fused together by the pressure in the star's core. One of the protons then transforms into a neutron by releasing a positron and a neutrino, and the proton–neutron pair forms the nucleus of a deuterium atom. The reaction produces 90% of the neutrinos that escape the Sun, but they are hard to detect on Earth where radioactive decay processes produce much more energetic neutrinos. Andrea Pocar of the University of Massachusetts Amherst and his colleagues have now used the Borexino detector at Gran Sasso National Laboratory in Italy to obtain the first direct detection of these low-energy neutrinos. The detector measures the flux of the neutrinos with a precision of 10%. If that precision can be increased to just 1%, it could provide a way of looking for a decrease in the neutrinos' energy as they pass through dark matter.
August 28, 2014 12:40 PM

Saturn’s rings yield clues to planet’s geology

New Scientist: Until now, scientists thought Saturn was composed of a solid central core surrounded by a turbulent mix of helium and hydrogen in gas and liquid forms. But vibrations detected in Saturn’s rings indicate that the planet may have a stable stratified layer of liquid and rock between its core and its roiling exterior. In his paper published in the journal Icarus, Jim Fuller of the Kavli Institute for Theoretical Physics in Santa Barbara, California, says that density waves within the rings reflect oscillation modes within the planet. Using interior structure modeling, Fuller was able to determine that the planet’s combination of gravity modes indicates the presence of a deep layer of stratification. It is the first time such a seismological investigation has been conducted on another planet.

August 27, 2014 5:00 PM

Ohio bill sparks evolution-vs-creationism debate

Ars Technica: A recent bill has been proposed in Ohio that aims to revoke the Common Core education standards, which have been recently adopted there and in many other states. Sponsored by Representative Andy Thompson (R-Lima), the bill targets math and literacy but also encompasses the teaching of science. Its call to “focus on academic and scientific knowledge rather than scientific processes” has sparked criticism that students will be forced to memorize facts without understanding how the knowledge was generated. In addition, critics say the bill’s ambiguous language would allow the teaching of intelligent design. Thompson counters that his intent was to keep politics out of the educational system and encourage kids to consider many different perspectives.

August 27, 2014 3:30 PM

China vies for lead in dark-matter detection

Science: Several large xenon detectors are currently searching for WIMPs, or weakly interacting massive particles, the hypothetical candidates for dark matter. Among them is China’s PandaX dark-matter experiment. With its location in the world’s deepest underground laboratory, PandaX is well situated to shield its tank of liquid xenon from cosmic rays and other signal background radiation at Earth’s surface. Although its current capacity is less than half that of the US’s Large Underground Xenon experiment, PandaX is expandable. Chinese researchers hope to increase its mass of liquid xenon from 120 kg to 500 kg by early next year. If so, PandaX could take the lead in sensitivity, if only until XENON1T, the next phase of the XENON Dark Matter Project located in Italy's Gran Sasso underground laboratory, is up and running.

August 27, 2014 2:20 PM

US and Australian companies collaborate to track space junk

BBC: Hundreds of thousands of pieces of space junk are whirling around Earth at speeds up to 28 000 km/hr. Most of the debris is manmade and includes spent rocket stages and destroyed satellites. To minimize the risk of collision with operational spacecraft, governments and private companies try to track it, primarily through the use of radar. Now US aerospace company Lockheed Martin and Australia’s Electro Optic Systems have announced they will be collaborating on the construction of a new tracking facility that will make use of optical and laser technology, which promises to be cheaper and more precise. The new facility, to be located in Australia, is expected to increase global tracking capacity by 25%.

August 27, 2014 12:20 PM

California’s recent earthquake adds stress to already-stressed fault zone

New Scientist: The magnitude 6.0 earthquake that shook Northern California on 24 August injured more than 200 people and caused hundreds of millions of dollars in damage. It may have also added stress to the nearby Hayward fault, which is almost 120 km long and parallels the San Andreas fault. The last major earthquake on the Hayward fault occurred 146 years ago, in 1868; in fact, the last five major events there were all about 140 years apart. “The fault is thought to be one that has a pretty high probability of rupturing in the next 30 years," says Thomas Parsons of the US Geological Survey. If so, the effects could be devastating because of the large urban areas, such as San Francisco and Berkeley, located there.

August 26, 2014 12:37 PM

Magnetic levitation and rotation of nonmagnetic objects

BBC: Delicate nonmagnetic objects with arbitrary shapes are hard to manipulate. Now, Anand Bala Subramaniam of Harvard University and his colleagues have developed a way to suspend and rotate such objects. They placed them in a paramagnetic liquid inside a chamber with magnets above and below it. Because the liquid is attracted to the magnets, its density increases near the top and bottom of the chamber. The object “floats” in the less dense area in the middle. Subramaniam and his colleagues found that by rotating the magnets, or by introducing an external magnet and moving it around the chamber, they could rotate the object within the fluid. The team’s next step is to attempt to manipulate multiple objects and assemble them into a single piece.

August 26, 2014 12:20 PM

Lens implant monitors for glaucoma

New Scientist: Glaucoma, the second most common cause of blindness, occurs when fluid builds up in the eye and damages the optic nerve. To monitor intraocular pressure, researchers have developed a tiny sensor that can be embedded into a synthetic lens. The sensor employs a fluid column, whose rise and fall can be read with a smartphone fitted with an optical adapter. Such constant monitoring would allow for better treatment of the disease, which involves the prescription of pharmaceuticals to lower the fluid pressure. Although the current device is limited to cataract patients who must have their natural lenses replaced anyway, the researchers are working on a standalone sensor that could find wider use.

August 26, 2014 12:15 PM

Brown dwarf may contain first known extrasolar water clouds

Science: Although some extrasolar objects have been found to have water vapor in their atmospheres, a brown dwarf just 7.3 light-years from Earth appears to be the first to have clouds made of water. Labeled WISE J0855-0714, the object was initially found in images collected by NASA’s Wide-Field Infrared Survey Explorer (WISE) between 2010 and 2011. Brown dwarfs are star-like objects whose masses are too low to sustain hydrogen fusion and too high to qualify the objects as gas giant planets. The cloudy brown dwarf is the fourth closest star system to Earth. It is Jupiter-sized but 3–10 times as massive and is the coldest known brown dwarf, with a temperature slightly colder than Earth’s average temperature but warmer than Jupiter’s. Jacqueline Faherty of the Carnegie Institution of Washington and her colleagues created a composite of the object from 151 near-IR images taken by the Magellan Baade telescope in Chile. The composite image revealed a pattern of colors that matched a model of brown dwarfs that contain clouds of water ice and of sodium sulfide. 

August 26, 2014 11:35 AM

China increases its satellite surveillance network

Los Angeles Times: China added to its ever-growing network of surveillance technology with the launch last week of the Gaofen-2 satellite. Its predecessor, Gaofen-1, has been providing data on earthquakes, floods, and smog since it was launched more than a year ago, according to Chinese authorities. Besides its extensive satellite network, China may have as many as 30 million surveillance cameras operating—which amounts to one for every 43 people. Despite successes in locating fields of opium poppy and marijuana and uncovering smuggling routes at the North Korean border, China’s surveillance network has provoked criticism from citizens who feel their privacy is being invaded. Nevertheless, the system is not as advanced as those of some other countries, including the US.

August 25, 2014 1:45 PM

Ernest Moniz asked to intervene in firing of Los Alamos National Laboratory scientist

Science: James Doyle, a political scientist who was employed at the Department of Energy's Los Alamos National Laboratory (LANL), was fired after publishing a scholarly article in which he debated the value of possessing nuclear weapons. Charles Ferguson of the Federation of American Scientists (FAS), an organization that supports arms control efforts, has petitioned DOE secretary Ernest Moniz to intervene. The FAS believes that the firing was in retaliation for Doyle's article, which takes a position in opposition to the currently accepted government policy. Doyle was let go by LANL, which is heavily involved in nuclear weapons research, after a procedural dispute led to the paper being retroactively classified. The laboratory claims Doyle's firing was a result of budgetary constraints.

August 25, 2014 1:10 PM

Hundreds of methane seeps discovered off US East Coast

BBC: At least 570 methane vents have been discovered off the US East Coast between North Carolina and Massachusetts, according to a study published in Nature Geoscience. Previous surveys had found only three. Adam Skarke of Mississippi State University and colleagues used multibeam sonar to map the water column over about 94 000 km2 of seafloor. They say the source could be methane hydrate, an icy solid formed from frozen water and methane, buried under sediments on the ocean floor. Furthermore, the researchers say that although methane gas has been bubbling up through the water column for more than a thousand years, warming ocean temperatures may be accelerating the process. The methane, however, does not appear to be reaching the ocean surface or the atmosphere; instead, it may be oxidizing in the water and forming carbon dioxide. Undersea sediments may hold 10 times as much carbon as the atmosphere. Worldwide there may be as many as 30 000 of those methane seeps.

August 25, 2014 12:50 PM

Iceland volcano erupts quietly below the ice

Nature: Although Iceland’s Bardarbunga volcano has started erupting, the eruption is taking place 150–400 m under the ice, and there have been no visible changes on the surface. Since mid-August, intense seismic activity in the area prompted the Icelandic Meteorological Office (IMO) to raise the aviation alert because of the possibility that ash and smoke from an eruption could disrupt air traffic. As of this weekend, when magma began to flow under the ice, the alert was heightened to red, the highest warning, but so far there has been little disruption to air travel. The area is being monitored from the air by scientists with the IMO and the University of Iceland and on the ground through the placement of additional seismic instruments and mobile radar observation stations.

August 25, 2014 11:40 AM

Texas county grants SpaceX no-tax land deal

Ars Technica: The deal that SpaceX is expected to sign to establish its commercial space launch center outside of Brownsville, Texas, exempts the company from paying county taxes for 10 years. According to the Brownsville Herald, the company is also receiving a total of just over $15 million from various state funds. The company estimates that establishing the facility will cost $85 million. Brownsville is one of the poorest cities in the US, based on median household income and poverty rates. SpaceX's facility is expected to add only 300 jobs locally, but secondary facilities that other companies will establish to support the spaceport will likely provide a further bump to the local economy.

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