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Updated: 7 hours 23 min ago

NASA extends missions of nine planetary spacecraft

5 July 2016

New York Times: On 1 July, NASA announced mission extensions for nine current spacecraft that have already completed their primary missions. The New Horizons probe, which flew past Pluto, will continue on to study the Kuiper belt object 2014 MU69. The other funded missions are Dawn, which is orbiting Ceres; the Lunar Reconnaissance Orbiter; the Mars Reconnaissance Orbiter; the Mars Atmosphere and Volatile Evolution orbiter; the Opportunity and Curiosity rovers on Mars; the Mars Odyssey orbiter; and the European Space Agency's Mars Express, for which NASA is providing support. Extensions for most of the missions were expected, but the inclusion of Dawn surprised the team that is managing the mission. The craft is low on fuel because of its reliance on thrusters after the failure of two reaction wheels. Now Dawn will remain in place around Ceres, where it will continue to make observations as the dwarf planet approaches perihelion.

Large data sets overwhelm facial recognition software

5 July 2016

IEEE Spectrum: Many facial recognition algorithms have a success rate above 95% when tested against databases of just a few thousand faces. A new test called the MegaFace Challenge evaluates the performance of algorithms when they are presented with a database of 1 million images of 690 000 people. The challenge is for the algorithms to evaluate whether two different pictures are of the same person and to determine if a given person is in the database. The success rates for all the tested facial recognition programs dropped significantly when faced with so much data. Google's FaceNet, the top-scoring algorithm tested, dropped from near 100% accuracy on the widely used Labeled Faces in the Wild (LFW) test to just 75% on the MegaFace Challenge. Several algorithms that scored above 90% on LFW dropped to below 60% accuracy. Ira Kemelmacher-Shlizerman of the University of Washington in Seattle and his colleagues organized the MegaFace Challenge to evaluate the effectiveness of facial recognition software in more realistic situations.

NASA’s <em>Juno</em> spacecraft achieves orbit around Jupiter

5 July 2016
Nature: On 4 July NASA’s Juno spacecraft successfully entered Jupiter’s orbit. Launched in August 2011, the craft took almost five years to make the roughly 2.7 billion km trip. Juno is to complete two 53-day orbits of the planet before burning its main engine and settling into a shorter, 14-day orbiting pattern. The first spacecraft in more than two decades to visit Jupiter, Juno will investigate the giant planet’s composition, Great Red Spot, and massive radiation belts. The ultimate goal is to gain insight into how Jupiter, and the entire solar system, evolved.

Ice-age temperature swings may have been caused by fluctuating Atlantic Ocean currents

1 July 2016
Science: During the last ice age, temperatures on Earth’s surface seesawed several times between the Northern and Southern Hemispheres: As the north got colder, the south grew warmer, and vice versa. Now researchers have found that the abrupt temperature changes in the two hemispheres may have been caused by a slowdown of the Atlantic Meridional Overturning Circulation (AMOC), an ocean current that drives shallower, warmer waters north and deeper, colder waters south. Studying a sediment core drilled from the Bermuda Rise in the Atlantic Ocean, Jerry McManus of Columbia University and colleagues say they saw at least four instances when the ratio of two radioactive daughter isotopes changed sharply, which indicated a weakening of the AMOC. Such slowdowns could have caused the north to receive less warm water and temperatures there to drop while the south heated up due to the backlog of warm water. What caused the slowdowns is still unknown, but one explanation is the breaking off of Canadian icebergs, whose melting would have increased the amount of freshwater in the North Atlantic and possibly disrupted ocean flow. Over some 1500 years, the freshwater would have dissipated, allowing the AMOC to increase once again in strength.

More than 100 Nobel laureates call for end to opposition of GMOs

1 July 2016

Washington Post: On 30 June more than 100 Nobel laureates, including 25 physics awardees, released a letter that called for the environmental activism group Greenpeace to end its opposition to the use of genetically modified organisms (GMOs) in agriculture. The letter primarily focused on Golden Rice, a form of rice that produces high levels of beta-carotene, a precursor of vitamin A. Golden Rice was developed as a potential crop for areas where the populations suffer from vitamin A deficiency. The letter says that Greenpeace has driven the resistance to the commercialization of Golden Rice and to GMOs in general, despite the lack of evidence that engineered crops are harmful. The signature campaign was organized by Richard Roberts of New England Biolabs, who shared with Phillip Sharp the 1993 Nobel Prize in Physiology or Medicine for the discovery of genetic sequences called introns.

Antarctic ozone hole appears to be shrinking

1 July 2016
Nature: Three decades after the introduction of the Montreal Protocol, the ozone hole over the Antarctic is beginning to disappear. The hole was first observed in the late 1970s, when scientists realized that the use of chlorofluorocarbons and similar substances in aerosol spray cans and cooling systems was having an adverse effect on Earth's ozone layer, which shields the planet from the Sun's UV radiation. Now Susan Solomon of MIT and colleagues, who have been monitoring polar ozone with weather balloons, say that since 2000 the Antarctic ozone hole has been shrinking in the month of September—a key time of year because it marks the beginning of the Antarctic spring and the return of more sunlight to the region. Although no measurable improvement has been seen in the hole over the Arctic, the researchers say the improvement in the Antarctic is a sign that the Montreal Protocol is having a positive effect. “We as a planet have avoided what would have been an environmental catastrophe,” says Solomon.

Tesla's Autopilot feature involved in fatal crash for first time

1 July 2016

Wired: On 7 May, a Tesla Model S driver, who was using the vehicle's semiautonomous Autopilot feature, died after the car crashed into a tractor trailer. In a statement Tesla indicated that the accident occurred when the tractor trailer made a left turn across a divided highway. The Model S went underneath the side of the trailer, which made contact only at the height of the windshield. Neither the vehicle's driver nor the Autopilot feature engaged the Tesla's brake. Tesla claims that the Autopilot (and the driver) failed to detect the white trailer, which would have been hard to see against the bright sky. The company says that its vehicles have accumulated more than 130 million miles using the feature without any other fatal accident. Autopilot, which must be activated by the driver, uses a combination of radar, cameras, GPS, and ultrasonic sensors to control the vehicle. When activated, it reminds drivers that they are supposed to keep their hands on the steering wheel and should be ready to assume complete control of the vehicle at any time.

NIF quest hobbled from the start

1 July 2016
Extra Dimensions: Any progress in the pursuit of laser-initiated fusion is overshadowed by the project’s failure to meet an absurdly ambitious deadline.

Emissions pledges may not be enough to meet climate goal

30 June 2016

Washington Post: Climate scientists have repeatedly found that if the global average temperature is kept from exceeding 2 °C over the preindustrial average, then many of the most significant effects of global warming will likely be avoided. However, according to a new study of the emissions-cutting pledges made in December 2015 by the 195 nations that gathered in Paris, those pledges are not going to be enough to keep global warming below the 2 °C threshold. Led by Joeri Rogelj of the International Institute for Applied Systems Analysis in Laxenburg, Austria, the researchers found that the pledged cuts will more likely limit the temperature increase to between 2.6 °C and 3.1 °C by 2100. According to the analysis, by 2030 humans will probably have released the maximum amount of emissions that could have limited warming to 2 °C.