Physics Today Daily Edition
Guardian: Last week, NASA's Kepler space telescope unexpectedly went into emergency mode, during which contact with the satellite became intermittent. Launched in 2009 and now situated roughly 120 million km from Earth, Kepler had a successful initial mission in which it detected nearly 5000 extrasolar planets by 2012. The following year, two of Kepler's four reaction wheels, which are used to stabilize the telescope, failed. NASA was able to repurpose the telescope for a mission dubbed K2. The unexpected loss of contact with Kepler occurred when the NASA team attempted to send commands to reorient the telescope just days before the start of a new survey. NASA was able to regain full communications with Kepler over the weekend and is now investigating what caused the emergency shutdown.
Scientific American: Two methods have been developed to determine the rate of the universe's expansion, called the Hubble constant. But they don't yield the same result. Researchers measuring the cosmic microwave background (CMB) radiation came up with a value of 67.3 ± 0.7 km/s/Mpc. Another group of researchers, who used the distance ladder method, now report a value of 73.02 ± 1.79 km/s/Mpc. The new study uses known cosmic distance markers, such as Cepheid variable stars and Type 1a supernovae, to calibrate measurements of galaxies' distances and redshift, or how quickly the galaxies are moving. That technique was used by Adam Riess of the Space Telescope Science Institute in Baltimore, Maryland, and his colleagues in the 1990s to prove that the universe's expansion was accelerating. Riess's team is also behind the latest study, which includes several new calibration points that yield a more precise value. Both the CMB and distance ladder research teams are continuing to examine their data and calculations to try to understand why the two systems still don't agree.
Ars Technica: A new model in the weather forecasting field is working to surpass the two current global contenders—the US Global Forecasting System and the European Center for Medium Range Weather Forecasting. Over the past several years, multinational electronics company Panasonic has been using weather information gathered by airplanes to develop its own global weather forecasting model. Sensors mounted on private aircraft have been collecting data on wind, temperature, and other weather parameters since the 1990s, when the Clinton administration instituted the policy to monitor potentially dangerous conditions during flight. Panasonic acquired that weather monitoring system, called TAMDAR, in 2013 and created its own weather forecasting unit, Panasonic Weather Solutions (PWS). Neil Jacobs, the company’s chief atmospheric scientist, claims that PWS has now surpassed its government competitors in accuracy, but experts say it is too soon to pass judgment. They say more forecasts will have to be made publicly available over the coming months before a just comparison can be made.
NPR: Supermassive black holes are at least millions of times as massive as the Sun and are commonly found at the center of large galaxies. The very largest known black holes, which can be a billion times as massive as the Sun, have only been found in dense clusters of very large galaxies. Those behemoths are thought to form when two black holes merge in a galactic collision. A newly discovered supermassive black hole challenges the idea that such collisions are only likely in dense clusters. Found in a relatively inactive group of average-sized galaxies, the black hole has a mass of about 17 billion Suns. Its unusual location suggests that such gargantuan black holes may be more common than previously thought.
IEEE Spectrum: Solar cells generate minimal electricity when it's cloudy or raining, but the rain does serve a purpose: It rinses dust off the cells. Now Qunwei Tang of Ocean University of China in Qingdao and his colleagues have succeeded in using the ionized salts in rain to keep solar cells generating electricity even when the weather is inclement. To attract the positively charged ions and induce a capacitor-like effect, Tang's team added a layer of graphene to an inexpensive thin-film solar cell mounted on a flexible backing. When slightly salty water was sprayed on the solar cells, they generated hundreds of microvolts of electricity, achieving a solar-to-electric conversion efficiency of 6.53%. Tang says that the proof of concept shows that solar cells could be adapted to generate electricity in all kinds of weather.
BBC: A new masterpiece has been created in the style of Dutch master painter Rembrandt—but not by human hands. Over the past two years Microsoft and others have been collaborating on a project to develop a computer program that can paint an original Rembrandt-style portrait. The researchers made three-dimensional scans of Rembrandt’s paintings and digitally tagged data on everything from content to lighting to brush-stroke style. Then machine-learning algorithms looked for characteristic patterns in the data. Finally, the computer was asked to create its own portrait in the style of Rembrandt. The final image was 3D printed using 13 layers of ink to replicate the height and depth of the paint in an actual Rembrandt work. The result, a remarkably realistic-looking painting of a middle-aged white male in period dress, is to be put on public exhibition and will be used to better understand “what makes a masterpiece a masterpiece,” said Emmanuel Flores, the project’s technology director.
IEEE Spectrum: Six years ago, IBM began work on a highly parallelized, low-energy computer chip—dubbed TrueNorth—that was inspired by the behavior of the human brain. In 2014, researchers completed the first of those 5.4-billion-transistor chips, which consume just 70 mW of electricity at peak operation. Now, the company has combined 16 of the chips into a single computer and sent it to Lawrence Livermore National Laboratory for testing. Researchers at the lab, which is home to several of the world's fastest supercomputers, will evaluate the technology to determine its potential usefulness for a variety of applications, particularly pattern recognition. Because supercomputers consume a lot of energy, the fact that TrueNorth uses significantly less power than conventional computer chips, even when it works on the most difficult tasks, could make it a key component in the development of exascale computing.
IEEE Spectrum: Diodes are electrical components that allow electricity to flow in only a single direction. Now a diode has been made from an 11-base-pair length of DNA combined with two molecules of coralyne. The combined molecule, which is roughly 4 nm long, allows electrical current to flow through it 15 times as strongly in one direction as in the other. The researchers believe that the coralyne molecules fuel the one-way movement of electricity by creating an imbalance in the distribution of electrons in the DNA.