Physics Today Daily Edition
NPR: The Diablo Canyon Nuclear Power Plant is the last nuclear plant still operating in California. On 21 June Pacific Gas and Electric announced that it would close the plant by 2025 and replace it with renewable energy sources. Diablo Canyon provides energy to 1.7 million homes. Local residents and environmental groups have continually raised safety concerns because the plant and its two nuclear reactors are close to active fault lines. Protests intensified following the earthquake and tsunami that damaged Japan's Fukushima Daiichi Nuclear Power Plant in 2011.
GeekWire: Trevor David of Caltech and his colleagues have spotted an intriguing planet orbiting K2-33, a star in the field of view of the Kepler space telescope during its extended K2 mission. The planet has a diameter about six times that of Earth, and it orbits its star every 5.4 days at a distance of 7.4 million km. Further examination of the system revealed that the star is still surrounded by gas and dust from the protoplanetary disk. The presence of the disk's remnants suggests that the planet is less than 10 million years old, since models of planetary system evolution predict that disks dissipate fairly quickly. Now researchers have to figure out why the youthful planet is so close to its star; most models suggest that large planets form far away and then migrate inward later.
BBC: China's new Sunway TaihuLight supercomputer at the National Supercomputing Center in Wuxi has first place on Top500's latest list of the world's most powerful supercomputers. At 93 petaflops (93 trillion floating point operations per second), the computer is twice as fast as the previous top computer—China's Tianhe-2—and three times as efficient. Sunway TaihuLight will be used primarily for advanced manufacturing, weather forecasting, and data analytics. For the first time, China has surpassed the US in the number of computers on the Top500 list, 167 to 165. China has two machines in the top 10—the top two. However, the US holds four of the first 10 spots.
IEEE Spectrum: The systems for managing cryptocurrencies such as Bitcoin are intended to be secure. But as with all software systems, there are flaws that some users attempt to exploit. On 17 June a public investment system called the DAO, which is built around the Ether currency, was exploited in a way that allowed the attacker to steal more than 3 million Ether (at the time equivalent to about $60 million). Participants in the DAO use Ether to purchase DAO tokens, which give them proportional ownership of the DAO and a proportional vote in the group's investments. The DAO is designed so that token holders can split off their shares and invest them for 27 days before returning the currency to the collective pot. The attacker managed to split away more than his or her original share of the collective investment. The person behind the attack now controls a split DAO that contains 100 times as many tokens as initially invested. Those surplus tokens were taken away from other investors. The developers behind the DAO are looking for a solution. Other than resetting the system to a point before the attack began, which is counter to the principles of block-chain currencies, there does not appear to be a way to restore the stolen funds to the original owners.
New York Times: On 17 June NASA administrator Charles Bolden announced that the agency is developing an all-electric airplane. Designated the X-57, the relatively small plane will have 14 motors embedded in its wings and a cruising speed of around 282 km/hr. Only two of the motors—60 kW each, driving 1.5 m propellers—will be used while the plane is cruising. The other dozen motors, 9 kW each and driving 0.6 m propellers, will be used during takeoff and landing; the propellers will be folded away when unused. The additional propellers are necessary because the wings are much narrower than traditional wings, which makes them more efficient for cruising but less so for takeoff. The project is starting from an extant plane, the four-seat Tecnam P2006T. The conversion will entail replacing the passenger seats with battery packs and adding instruments for the pilot. The battery capacity should allow the plane to be airborne for about an hour; NASA is investigating the use of fuel cells instead of batteries to increase the flight time. The agency also expects to be able to scale up the technology for commuter and regional airlines.
NPR: On 16 June Russia launched the Arktika, a 173 m icebreaker powered by two nuclear reactors. Designed to break through ice up to 4 m thick, the Arktika is part of Russia's growing Arctic naval development, which includes building new bases in the Arctic Circle and modernizing nuclear submarines. Russia is the only country with nuclear-powered icebreakers. It already has more icebreakers—over two dozen—than all other nations combined.
Thanks to geometric tricks, behavior associated with massive, charged particles can emerge in an ordinary beam of light.
New Scientist: Oil's stickiness is what makes it hard to remove from plants and animals, so cleaning up spills before they reach fragile environments is crucial. Yi Du of the University of Wollongong, Australia, and his colleagues have found a quick and potentially cheap way of cleaning up oil spills; their method that uses iron oxide nanoparticles and magnets. In tests in small water tanks, the 25 nm particles bonded with the oil, making it easy to collect using a simple magnet. The next step is testing the technique in larger tanks to see if it scales up well before testing it in open water. The iron oxide particles are nontoxic, and any excess could also be collected with magnets and reused, which would limit their risk to the environment.
New York Times: More than 50 000 meteorites have been found on Earth, but one is unique and belongs to a group of meteorites that haven't fallen to Earth in 470 million years. The meteorite was found with more than 100 others collected from a limestone quarry in Sweden by Birger Schmitz of Lund University and his colleagues. It shared certain characteristics with the others in the collection that suggested it fell at the same time as they did, but it was otherwise distinct from all other known meteorites. Schmitz's team believes the unique meteorite was once part of an asteroid that was destroyed in a collision with the asteroid that created the other meteorites they collected.
MIT Technology Review: Social media is widely used by terrorists and other groups to organize themselves. Neil Johnson of the University of Miami in Florida and his colleagues have developed an algorithm they say could help minimize the ability of such groups to organize. They developed the algorithm by studying a Russia-based social platform called VKontakte, which has 360 million users from around the world. They identified nearly 200 groups that shared content suggestive of a concrete connection to the terrorist group ISIS. Calling these groups "aggregates," Johnson's team watched them grow and coalesce over a six-month period and developed a behavior model based on the aggregates' day-to-day behavior. The model reveals some general and social media behaviors that the researchers believe could be used to prevent the organization of terrorist groups online. They say such efforts should focus on identifying aggregates, which are less numerous and easier to identify than individuals, and should specifically target smaller aggregates before they merge into larger ones. The model also revealed that the rate of aggregate formation increased in the periods leading up to major events, such as the ISIS attacks in Kobane, Syria.
Science: On Thursday, after examining a report from outside experts, the governing council of the ITER fusion project announced that the scheduled startup date for the reactor would be pushed back 5 years to December 2025. They also slightly trimmed the expected costs of the next several years of construction and the first years of operation down to just under €4 billion ($4.5 billion). The cost savings are expected to come from delaying the construction of some components of the system, which aren't necessary for the initial startup, until after the facility creates its first plasma. The additional funding is on top of the €18 billion already funded, but the council says that stretching out the schedule will lower the annual costs to contributing countries.
Climate Central: The last atmospheric monitoring station on Earth that had not detected carbon dioxide levels above 400 ppm has now done so. Three years ago the first such reading was made by a station on Mauna Loa in Hawaii; last year the global average cleared the same level. But the station located at the South Pole did not do so until 23 May 2016. The last time CO2 levels were that high at the South Pole was 4 million years ago. The 400 ppm level is a symbolic one, but the spread of CO2 globally is not, with particularly high concentrations in the populated Northern Hemisphere spreading to Earth's most remote regions.