Physics Today Daily Edition
New York Times: A long-standing conspiracy theory suggests that the condensation trails that form behind planes as they fly at high altitudes are actually "chemtrails" produced by aircraft spraying chemicals into the sky for sinister reasons. Steven J. Davis of the University of California, Irvine, and his colleagues have now published the first peer-reviewed study that examines and debunks a wide range of claims made by supporters of the chemtrail theory. The study surveyed 77 atmospheric scientists, who were asked to provide scientific explanations for such phenomena as the occasional gap in a contrail or elevated chemical levels in the atmosphere. Davis said the goal of the study is to counter the misinformation that appears to be rife on the internet.
Spaceflight101: On 15 August China launched the Quantum Science Satellite into orbit aboard a Long March 2D rocket. The satellite carries a crystal that generates entangled pairs of photons. An optical communication system splits each pair and transmits one of the photons to a ground station in either Vienna, Austria, or Beijing, China. The photons are then used to generate encryption keys. Researchers have tested similar setups on Earth's surface by using two stations spaced a few hundred kilometers apart. The Quantum Science Satellite will be the first space-based communications test system.
Nature: One of Stephen Hawking's most famous predictions is that black holes evaporate and disappear due to the emission of radiation. That radiation has not been spotted directly, but now an analog to the phenomenon has been detected escaping from an artificial black hole. Created by Jeff Steinhauer of the Technion–Israel Institute of Technology in Haifa, the so-called black hole is a Bose–Einstein condensate (BEC) of supercooled rubidium atoms. The event horizon is created by accelerating the atoms until they exceed the speed of sound in the medium. Steinhauer says that the BEC then experiences quantum fluctuations of pairs of entangled phonons on either side of the event horizon.
Nature: One explanation for the dominance of matter over antimatter in the universe is that a superheavy primordial particle cousin to neutrinos decayed in a matter-favored process. The Tokai to Kamioka (T2K) experiment is designed to test that proposal by measuring neutrino oscillations—when one of the three flavors of neutrino turns into another. Muon neutrinos and antineutrinos are shot from the Japan Proton Accelerator Research Complex to the Super-Kamiokande detector 295 km away. Over six years of operation, the researchers expected to see 24 electron neutrinos and 7 electron antineutrinos. (The disparity exists because antimatter is harder to produce and detect.) Instead, T2K scientists have seen 32 electron neutrinos and 4 electron antineutrinos. That signal is intriguing but well below the threshold needed to rule out statistical variation. T2K would need to produce 13 times as much data to come to a solid conclusion but is slated for only five more years of operation. However, a second, similar experiment called NOvA at Fermilab will switch from shooting neutrinos to antineutrinos next year. The two groups intend to combine their data and expect to have enough to produce a 3 σ signal by 2020. It will take the next generation of neutrino experiments to reach the 5 σ level required to announce a discovery.
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.