Physics Today’s online staff summarize the most important and interesting news about science from the world's top media outlets.
Nature: After passing by Pluto last month, NASA's New Horizons had enough fuel to adjust its course to visit another body in the Kuiper belt, but its second destination had yet to be chosen. On 28 August, NASA announced that the craft would target 2014 MU69, with an expected arrival date of 1 January 2019. The New Horizons team found 2014 MU69 with the Hubble Space Telescope. All that is known about it is that it is a "cold classical" Kuiper belt object (KBO) with a diameter of 45 km. Unlike Pluto, KBOs have relatively circular orbits, undisturbed by the giant planets in the outer solar system. New Horizons will pass within 12 000 km of 2014 MU69, as close as it passed Pluto. Afterward, it will continue to take pictures of other KBOs but at a distance of about 15 million km.
Ars Technica: On Friday, Tesla announced that it has signed a 5-year deal with Bacanora Minerals Ltd and Rare Earth Minerals Plc to purchase lithium mined in northern Mexico. The deal will require the companies to establish the mine, which has not yet been built, and processing facilities to produce lithium hydroxide and lithium carbonate. When the mine begins operations, it is expected to produce 35 000 tons of the lithium compounds per year. That amount will eventually expand to 50 000 tons. Once the mine has begun operating, Tesla will purchase the produced lithium at below-market rates for use in its Gigafactory, currently under construction in Nevada. Tesla will be able to contribute to the mining companies' fundraising for construction of the mine, which they previously estimated would cost $114 million.
Nature: Quantum mechanics suggests that entangled particles share the same states and can communicate with each other instantaneously, regardless of the distance that separates them. Albert Einstein rejected that idea, which he labeled "spookiness," and proposed instead that perhaps entangled particles have a predefined set of hidden properties that determine their later behavior. In the 1960s John Bell proposed that hidden variables could explain only a certain level of correlation, and several tests of that proposal have all favored spookiness. Those tests, however, had loopholes, either because too many of the entangled particles weren't detectable or because the particles were too close together to tell if the "communication" between them was faster than light. Now, Ronald Hanson of Delft University of Technology in the Netherlands and his colleagues have performed the first Bell experiment that closes both loopholes. They used entangled photons to entangle electrons that were separated by 1.3 km, far enough apart to detect a time delay. When they measured the electrons, they detected enough of the entangled particles to surpass the threshold that Bell set. And the overall result of the experiment confirmed the standard quantum mechanical view of spooky action at a distance.
New Scientist: Inflation, the sudden growth spurt the universe experienced shortly after the Big Bang, required a massive amount of energy. But what provided that energy is still unknown. A new theory proposed by Arjun Berera of the University of Edinburgh, UK, and his colleagues suggests that the early universe could have been flooded with gluon-like particles that formed "flux tubes." Those tubes, which Berera likens to the field lines seen in iron filings around a magnet, would have been incredibly densely packed together. Because the tubes behave like string, they could have become knotted, and that tangle may have contained enough energy to drive inflation. As the universe expanded past a certain point, the knots would have unraveled or broken, which slowed its growth. In addition, knots can form in only three dimensions. If, according to some theories, other dimensions do exist, Berera's theory could explain why we can see only three of them.
Wall Street Journal: One of the apparent consequences of Stephen Hawking's theory that black holes leak radiation is that over time they would evaporate and disappear. The information about all the particles they absorbed would then be lost. That concept, however, contradicts a tenet of quantum mechanics that information cannot be lost or destroyed. On Tuesday, at a conference at the Royal Institute of Technology in Stockholm, Sweden, Hawking presented a new theory about how that information might be preserved: Instead of being stored in the interior of a black hole, the information may be stored in its boundary, the event horizon, and then carried away by the emitted radiation.
Los Angeles Times: Satellite images of the Middle East over the past 10 years have revealed a drop in the levels of nitrogen oxide, sulfur dioxide, and other air pollutants. The drop does not appear to be the result of any clean-air laws or other changes but does coincide with the spreading conflicts there. Jos Lelieveld of the Max Planck Institute for Chemistry in Mainz, Germany, and his colleagues found the trend in data collected by the Ozone Monitoring Instrument on NASA's Aura spacecraft. They were studying the impact of air-quality standards adopted by countries in the region. Since 2011, when the Arab Spring protests reached Syria and escalated into civil war, the concentration of NO has dropped by 40% over Damascus and by 50% over Aleppo. Similar drops in emissions were noted in Iraq and Egypt. However, emissions rose in Beirut and other parts of Lebanon, probably because of the flood of refugees to those countries.