Physics Today Daily Edition
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.
The Atlantic: Despite making history with their announcement in February of the first direct detection of gravitational waves, researchers at the Laser Interferometer Gravitational-Wave Observatory (LIGO) aren't resting on their laurels. On Wednesday they announced a second confirmed gravitational-wave detection. The gravitational waves detected on 26 December 2015 were caused when two black holes merged about 1.4 billion years ago.
Nature: On 23 June the UK will vote on whether to remain in the European Union (EU). If it votes to leave, the UK will lose significant access to scientific research funding, opportunities for collaboration, and unique research facilities. Nature's editors argue that the benefits gained by membership in the EU greatly outweigh any concerns over diminished sovereignty. The EU will spend more than €120 billion ($135 billion) on research and innovation between 2014 and 2020, with €13 billion going to the highly successful European Research Council, which provides grants to researchers throughout the EU. In an earlier Nature survey, a large majority of UK researchers supported remaining in the EU.
The Verge: On Wednesday, SpaceX launched a Falcon 9 rocket carrying two satellites to geostationary transfer orbit. As with its other Falcon 9 launches, the company attempted to return the first-stage booster to Earth by landing it on a drone ship in the Atlantic Ocean. But unlike the previous four landings, this one was unsuccessful. The live video stream from the drone ship was interrupted during the landing, so the result wasn't known for some time. After an initial report of failure, SpaceX CEO Elon Musk confirmed that the first stage suffered a "rapid unscheduled disassembly" due to low thrust in one of the three engines needed for landing.
Science: Each February, researchers working at the Amundsen–Scott South Pole Station return home, leaving just a few dozen people on site for the Antarctic winter. On 14 June a pair of planes left Canada on a six-day trip to the research station to evacuate a crew member suffering from an unspecified medical emergency that requires hospitalization. Most medical problems are handled on site with help from doctors via remote camera feeds. The research station does not have a paved landing strip, so planes are required to land in the dark, on compacted snow, with landing skis instead of wheels. And the planes themselves have to be capable of operating in extreme cold. The two planes are propeller-driven Twin Otter aircraft that are used to transport researchers to Arctic research stations. One will land at the British Antarctic Survey's Rothera Research Station on the Antarctic Peninsula and stay there as backup; the other will continue the additional 2400 km to the South Pole.
New Scientist: A chiral molecule is one that exhibits different properties from its mirror-image molecule. All organic molecules are chiral, and the molecules that are common in life on Earth are primarily left-handed. Now, Brett McGuire of the National Radio Astronomy Observatory in Virginia and Brandon Carroll of Caltech have found the first chiral molecule in interstellar space. The molecule they found, propylene oxide, isn't necessary for life. But the researchers hope that studying chiral molecules in space might provide clues about why one direction of chirality is favored over the other.
IEEE Spectrum: In May, startup company Nikola Motors began taking pre-orders on a $375 000 hybrid electric tractor trailer called the Nikola One. On 13 June the company issued a press release claiming $2.3 billion in pre-sales in the first month for the truck, even though the company has yet to share a prototype. What is known about the proposed truck is that it will use a 400 kW compressed natural gas turbine to feed electricity into a 320-kW-hr battery pack that then powers electric motors. Nikola Motors says that the resulting fuel efficiency will be between 8 mpg and 12 mpg, with a fuel tank storing 100 gallons of fuel. The Spectrum article translates the $2.3 billion in pre-sales to just over $10 million in fully refundable deposits.
New York Times: The Bramble Cay melomys—the only mammal endemic to the Great Barrier Reef—has disappeared from the atoll off the shore of northern Australia on which it lived. According to Luke Leung of the University of Queensland and his colleagues, rising sea levels caused by climate change resulted in the atoll's occasionally being covered by seawater and its overall surface area being reduced; the changed water levels have destroyed the melomys's habitat and food sources. The disappearance of the species is the first documented extinction of a mammal caused by human-driven climate change. The melomys was first documented by European sailors in 1845. In the 1970s researchers counted hundreds of the animals on the atoll. But surveys in 2002 and 2004 found no more than a dozen animals, and a 2014 survey by Leung and his colleagues found neither animals nor evidence of their presence.
US News & World Report: On 13 June, at a meeting marking the 20th anniversary of the Comprehensive Nuclear-Test-Ban Treaty, US undersecretary of state Rose Gottemoeller said the treaty was a major force for good in the world—despite the fact that neither the US nor 7 of the 43 other nuclear-capable nations have ratified it. Domestic politics has prevented ratification in the US. Gottemoeller encouraged other nations to go ahead with ratification and said the Obama administration is still firmly in favor of the treaty. The continued lack of ratification has not diminished the administration's goals of reducing the domestic nuclear stockpile and fighting the global spread of nuclear weapons, she added.
IEEE Spectrum: A three-day event last week hosted by the Internet Archive featured a range of early internet luminaries who discussed problems with the way the internet has developed and proposed solutions. The speakers included Tim Berners-Lee, inventor of the World Wide Web and director of the World Wide Web Consortium; Vint Cerf, commonly known as the father of the internet; Brewster Kahle, founder of the Internet Archive; and Cory Doctorow of the Electronic Frontier Foundation. They all supported the idea of a decentralized internet, in which people would be freely connected without the limitations imposed by sites such as Facebook, Flickr, and LinkedIn that have created their own mostly closed systems. The internet evangelists also said that a decentralized Web would help prevent the kind of surveillance revealed by Edward Snowden and the restriction of access exemplified by China's Great Firewall, while also allowing people even greater levels of privacy for their personal information.
Los Angeles Times: While exploring Marias Pass in Gale Crater, Curiosity drilled into an area of rock that was curiously high in silicon and oxygen. An x-ray scattering analysis of the sample revealed that the rock contains the mineral tridymite, which had not previously been found on Mars. On Earth, tridymite is formed from the high temperatures and low pressures associated with violent volcanic explosions, such as the famous Mount St Helens eruption in 1980. It would be surprising if a similar type of eruption took place on Mars because all previous evidence of volcanism suggests eruptions resembling the steady flows of the Hawaiian island volcanoes. Explosive volcanoes are also primarily associated with plate tectonics, for which there has been no other evidence found on Mars. It's unclear how the tridymite formed and how it ended up in sedimentary rock at unusually high concentrations.
Nature: In South Korea, all able-bodied men between 18 and 35 years old are required to serve two years in the military, with few exceptions. Those exceptions include technical research personnel (TRP), roughly 2500 men with master's degrees in science and engineering. Instead of serving active duty, students can either enter a PhD program for three years or take a research position in the government or private industry. On 17 May the South Korean defense ministry announced a predicted shortfall of up to 30 000 troops by 2023. The ministry's proposed solution is to eliminate all exemptions, including TRP, beginning in 2018.