Physics Today Daily Edition
New Scientist: In 2000 an unusual meteorite fell onto icy Tagish Lake in British Columbia, Canada. Its composition was significantly different from that of other meteorites that have fallen to Earth. Previous analyses of the meteorite have suggested it is a D-type asteroid, which is rare in the asteroid belt but much more common around the solar system's gas giants. Now Bill Bottke of the Southwest Research Institute in Boulder, Colorado, and his colleagues have suggested that the Tagish Lake meteorite and other similar rocks that have been seen in the asteroid belt might come from the Kuiper belt. The researchers say the movement of the outer planets early in the formation of the solar system could have launched the asteroids inward. If so, the Tagish Lake meteorite could prove to be a handy point of reference for scientists anticipating the New Horizons spacecraft's visit to Kuiper belt object 2014 MU69 in 2019.
New Scientist: When a solar system forms, all the components should orbit in the same direction about the central axis. But Matthew Holman of the Harvard–Smithsonian Center for Astrophysics and his colleagues have now found an object orbiting the Sun at an angle 110° from the plane of the solar system. Dubbed Niku, the object was discovered by the Panoramic Survey Telescope and Rapid Response System 1 Survey on Haleakala in Hawaii. Niku is 160 000 times fainter than Neptune, meaning it could be less than 200 km in diameter. The new trans-Neptunian object does not appear related to the collection of highly inclined objects that some astronomers think could be evidence of Planet Nine, a large object well outside the orbit of Pluto.
Science News: When the Higgs boson was discovered in 2012, researchers at CERN were already looking forward to the next runs of the Large Hadron Collider (LHC). According to Tiziano Camporesi of the CMS experiment at the LHC, the current run has already begun clarifying the presence or lack of variations in the production and decay of the particle. The higher collision energies have provided hints but not yet proof of a theorized process in which the Higgs and two top quarks are produced together. Evidence for the Higgs decaying into bottom quarks, which should occur in more than half of Higgs decays, is still hard to isolate because of the many other ways in which bottom quarks are produced.
Nature: Global internet traffic is growing by about 22% per year, with demand from mobile alone growing at an estimated 53% rate. The infrastructure to handle that growth is outdated in many areas and occasionally gets overwhelmed. In some cases private companies like Google, Microsoft, and Facebook lay high-bandwidth fiber optic cables between countries, yet many areas still use legacy copper telephone cables. On the mobile side, second-generation (2G) networks are being phased out in favor of 3G and 4G networks in much of the world but still account for 75% of mobile subscriptions in Africa and the Middle East. Even at 100 megabits per second, 4G networks will need to be upgraded to 5G, which is 100 times faster, by the mid 2020s to meet expected data demands. Those networks will have to support significantly more devices with the growth of the "Internet of Things"—networked devices such as fitness trackers, home appliances, and more.
BBC: Dissolvable batteries have been a goal of researchers for years because of the potential to reduce electronic waste and perhaps operate inside the human body. Now Reza Montazami of Iowa State University in Ames and his colleagues have developed what they say is the first practical, dissolvable lithium-ion battery. The 2.5 V battery is 5 mm × 1 mm × 6 mm and houses the electrodes and electrolyte between two layers of a polyvinyl alcohol-based polymer. When exposed to water, the casing swells and the electrodes break apart; the full process takes around 30 minutes. Scaling the battery up is possible, but the cell would take longer to dissolve. Montazami's team suggests the battery could be used for powering environmental monitoring devices. The lithium-ion chemistry, however, is not suitable for use in the body.
New Scientist: First spotted by NASA's Kepler space telescope, KIC 8462852 drew scientific attention because of its erratic changes in brightness. The star dimmed at irregular intervals by up to 20%, whereas most of the stars Kepler saw dimmed regularly and by no more than 1%. One astronomer suggested the variations were caused by aliens constructing a Dyson sphere, a proposal that garnered widespread popular attention. Since then another researcher has dug up archival images revealing a gradual decrease in the star's brightness over the past 100 years. Now, Benjamin Montet of Caltech and his colleagues have examined more Kepler data and found a different dimming behavior. For the first 1000 days of the Kepler mission, KIC 8462852 dimmed at roughly 0.34% per year, twice the rate indicated by the archival images. Then, in just 200 days, the brightness dropped another 2.5% before beginning to level out. The new result makes it even more difficult to find a known phenomenon or combination of phenomena to explain the behavior. The leading explanations include a comet swarm or gas cloud around the star.