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Updated: 35 min 42 sec ago

July sets several heat records

16 August 2016
Climate Central: Based on records that go back to 1880, this past July was the hottest July and also the hottest month on record globally, according to NASA. And there’s a good chance 2016 will be the hottest year to date, says Gavin Schmidt, director of NASA’s Goddard Institute of Space Studies. Although a recent strong El Niño is partly to blame, most of the heat wave has been caused by the trapping of warm air by atmospheric greenhouse gases. With temperatures throughout the first half of the year about 1.5 °C above preindustrial times, it may prove difficult to achieve the 2 °C limit on global temperature that was set for the 21st century by world leaders at last year’s Paris climate talks.

Hawking radiation–like effect seen around artificial black hole

16 August 2016

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.

Plasma discharge for food sterilization

15 August 2016
For effective decontamination, bacteria on food surfaces must receive sufficient exposure to lethal agents.

Saturn moon may have methane-filled canyons

15 August 2016
New York Times: NASA’s Cassini spacecraft has pinged Saturn’s largest moon and found deep canyons probably filled with liquid methane. By bouncing radar signals off the moon’s surface, Valerio Poggiali of Sapienza University of Rome and colleagues were able to determine that the canyons are about 1600 m wide and up to 570 m deep. Based on reflections off the canyons’ surfaces, the researchers say the canyons could be filled with liquid, probably the same as that filling the nearby sea into which the channels flow. Because of Titan's extremely low temperatures, methane can exist as liquid, ice, and vapor, much like water does on Earth.

NASA's asteroid-sampling mission to launch in September

15 August 2016
Ars Technica: On 8 September, NASA's OSIRIS-REx spacecraft is scheduled to launch aboard an Atlas V rocket on a two-year journey to the asteroid Bennu. The probe will orbit the 500-m-wide asteroid, taking high-resolution images of the surface and collecting other data. The primary mission of sample return begins nearly two years after the initial data-taking phase. The probe will use a 3 m arm to collect at least 60 g of surface material. The goal is to compare the composition of a pristine asteroid with the remnants of asteroids that have fallen to Earth as meteorites. In a previous mission, Japan's Hayabusa spacecraft managed to grab only about 1500 grains from a stony asteroid. Bennu, on the other hand, is a carbon-rich asteroid. Such asteroids are considered a possible source of Earth's hydrocarbon molecules.

Neutrino oscillations provide hint of antimatter imbalance answer

15 August 2016

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.

US officials express opposition to Obama’s “no first use” nuclear proposal

15 August 2016
Wall Street Journal (via MarketWatch): With just a few months left in office, President Obama may have to give up on the “no first use” proposal he is considering, whereby the US would use nuclear weapons only if it were attacked with nuclear weapons. Among those opposed to the plan are several key cabinet members, including Secretary of State John Kerry, Secretary of Defense Ash Carter, and Secretary of Energy Ernest Moniz. The officials say that US allies such as the UK, France, Japan, and South Korea rely on the US for their security. Were the US to adopt such a policy, those countries might feel the need to develop their own nuclear programs. In light of the opposition the plan has met, it appears unlikely that Obama will press the issue.