Physics Today Daily Edition
Verge: Last year, a team of Russian astronomers, using the RATAN-600 radio telescope, detected a mysterious signal that came from the general direction of HD 164595, a Sun-like star located 95 light-years away. Because the star has at least one planet, the astronomers say it's possible the signal indicates the presence of an alien civilization. The team only recently shared the discovery with the rest of the SETI (search for extraterrestrial intelligence) community, and no other researchers have yet confirmed the signal. Verifying the discovery will be difficult for several reasons. RATAN-600 was using a wide-bandwidth receiver, so it will be hard to determine the precise source of the signal. Moreover, the signal hasn't repeated, and even if it did, it would be difficult to know where to point other radio telescopes to try to detect it. Since the telescope data suggest that the signal would have required more power than has been consumed by all of humanity, a more likely explanation is that it was caused by a natural phenomenon such as a quasar.
Business Insider: On 27 August NASA's Juno spacecraft performed its first flyby of Jupiter. In doing so, the probe reached 130 000 mph (209 214 km/h), the top speed ever attained by a human-made object. Juno began collecting a range of measurements and also took pictures—the first close-ups of the giant planet since 2007, when New Horizons passed by on its way to Pluto. by the end of 2016, Juno's highly elliptical orbit around Jupiter will bring the probe close to the planet every 14 days for the next 16 months.
Nature: Since the 1990s the Mathematics Genealogy Project (MGP) has been building family trees for professional mathematicians based on their doctoral advisers. An analysis performed by Floriana Gargiula of the University of Namur in Belgium and her colleagues has found that of the more than 200 000 mathematicians in the MGP database, 65% can be traced back to just 24 families. The analysis was done by combining the MGP data with information from Wikipedia and the Scopus bibliographic database. Overall, the analysis found 84 distinct families. The largest family, with 56 387 descendants, is headed by 15th-century physician Sigismondo Polcastro.
New Scientist: In the wake of last week's deadly magnitude 6.2 earthquake in central Italy, the country is preparing for final tests of a national earthquake forecasting and warning system. Italy's Civil Protection Department is developing a system that will collect seismic measurements from around the country and combine that data with mathematical models and historical records. Every three hours the system will spit out a report that predicts the number of earthquakes the country will experience in the next seven days. Warner Marzocchi of the Italian National Institute of Geophysics and Volcanology in Rome says that the system will likely be very good at predicting aftershocks, though it will not be able to predict magnitude. Predicting quakes like last week's will be difficult because of the absence of warning tremors.
New York Times: Fire whirls are tornado-like phenomena that often occur during large fires. They can be extremely damaging because the vortex causes the fire to burn much hotter. Inspired by a video of a fire whirl that ignited on a spill of bourbon in a pond at the Jim Beam distillery in Kentucky, Huahua Xiao, Michael Gollner, and Elaine Oran of the University of Maryland, College Park, have found that the whirls could possibly help in cleaning up oil spills. They poured n-heptane, an ingredient in some fuels, into a pan of water, ignited it, and then channeled air toward the fire to create a vortex. The resulting fire whirl soon changed from a yellow flame to a blue flame, indicating that burning was occurring at a significantly higher temperature and more efficiently, thereby producing less soot. A subsequent test using crude oil had similar results. The blue fire whirl is, as far as the researchers have found, a previously undocumented phenomenon. The Maryland team hopes to test the phenomenon at a larger scale to determine whether it could be useful for oil-spill cleanup.
BBC: When two turbines off the coast of Shetland, an archipelago off northern Scotland, were recently connected to the country's electrical grid, they became the first offshore tidal generators to provide commercial electricity. The two 100 kW generators were installed by Nova Innovation, an Edinburgh-based tidal energy company. Scotland has invested significantly in tidal energy generation because the country has some of the most powerful tides in Europe.
The Guardian: Greenland's ice sheet is one of the largest on Earth. Malcolm McMillan of the Center for Polar Ice Observing and Modeling in the UK and his colleagues recently used the satellite Cryosat-2 to map Greenland with a resolution of 5 km. The satellite uses radar altimetry to measure the height of the surface. By taking images over time, the researchers were able to measure changes in height; an increase in height corresponds to an increase in ice thickness. However, those measurements don't account for changes in density (the top layer could be ice or snow), surface roughness, water content, and other factors. McMillan's team examined the satellite imagery collected between 2011 and 2014 and accounted for all the variations. The scientists calculated that 270 billion tons of ice was lost per year, closely matching previous measurements from other groups using different measurement techniques. They also found that the western part of the sheet experienced more ice loss than the eastern side, and that a region less than 1% of the area of the sheet was responsible for 10% of the ice loss.
Korea Times: South Korea's National Fusion Research Institute announced on 24 August that it has developed a process capable of producing 50 kg of tritium breeder pebbles per year. Tritium, a radioactive isotope of hydrogen with one proton and two neutrons, is a common fuel for nuclear fusion reactors. Unlike hydrogen's other isotope, deuterium, tritium does not occur naturally in large quantities and so has to be artificially produced. Previous processes have not produced significant quantities of the isotope. According to the Institute for Energy and Environmental Research, between 1955 and 1996 the US produced an estimated 225 kg of tritium.
Washington Post: Dark matter accounts for much of the mass in the universe, but it is not evenly distributed. About 83% of the Milky Way's mass is due to dark matter; the percentage is considerably higher for some dwarf galaxies. Now Pieter van Dokkum of Yale University and his colleagues have found a galaxy, called Dragonfly 44, that has roughly the same mass as the Milky Way yet has only 1% as many stars. The researchers estimate that 99.99% of the galaxy's mass is from dark matter. Because Dragonfly 44 is about average when it comes to galactic size, scientists suspect that similarly dark matter–dominated galaxies are relatively common.
BBC: Earthquakes aren't the only phenomena to send seismic waves through Earth's interior. When a large storm forms water, the energy from colliding ocean waves can create weak seismic activity—dubbed a microseism—that travels through the crust. The pressure-wave microseisms from storms have been tracked regularly, but the transverse S waves, which move much more slowly, have never been tied directly to a storm until now. Kiwamu Nishida from the University of Tokyo and Ryota Takagi of Tohoku University used a dense network of seismic detectors off the Japanese coast to measure S waves and pin their source to a storm off the coast of Greenland. Researchers should be able to learn about Earth's interior structure by comparing the propagation of S and P waves from the same storm.
Ars Technica: In April, Russian billionaire and physicist Yuri Milner announced that he was providing $100 million for the research and development of an interstellar probe, a project he dubbed Breakthrough Starshot. The goal of the project is to accelerate tiny spacecraft up to 20% the speed of light so they could reach the closest star system, which includes Proxima Centauri and its newly discovered planet, in just 20 years. Now a team of researchers has calculated just how risky a trip at that speed would be. The scientists found that although heavier atoms in interstellar gas, such as oxygen, magnesium, and iron, could damage the vehicle, they would probably erode the ship's surface by only about 0.1 mm. However, interstellar dust would have a much more significant impact, eroding 1.5 mm of the spacecraft's surface and also causing localized melting as deep as 10 mm. The researchers say that much of the damage could be minimized or avoided by adjusting the spacecraft's design.