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Updated: 1 hour 13 min ago

Magnetic reconnection event monitored directly for the first time

13 May 2016

Space.com: A magnetic reconnection is an explosive release of protons and electrons that occurs when plasma from the Sun collides with a region of Earth's magnetosphere that has an oppositely directed magnetic field. The radiation released poses a threat to astronauts and satellites in orbit and to electrical systems and nuclear fusion experiments on the ground. But until recently, magnetic reconnection was studied only via theory and in laboratories. NASA's Magnetospheric Multiscale (MMS) mission—a set of four satellites in orbit around Earth—has now provided the first direct observations of those events. The satellites, which are each equipped with 25 of the fastest sensors NASA has put into orbit, take readings every 30 ms to track the motion of electrons. On 16 October 2015 MMS passed directly through a magnetic reconnection region, where the local magnetic field dropped to nearly zero, ions traveled in opposite directions, and electrons got accelerated by a strong electric field. The satellites detected a spike in the electric power generated by the electrons, a predicted behavior that had not been seen before. The mission research team next plans to move the satellites closer together so they can all enter a magnetic reconnection region simultaneously.

Brazilian scientists upset by apparent demotion of science ministry

13 May 2016

Nature: Upon taking over for Brazil's impeached president Dilma Rousseff, interim leader Michel Temer quickly acted to combine the ministry that deals with science and technology with the ministry that oversees telecommunications and internet regulations. The new "superministry" is subdivided into divisions, of which science is now one of the main offices. Many Brazilian scientists are unhappy with the move, which they say will further erode the ministry's authority and ability to support and fund research. The reorganization comes after several years of extreme cuts to science funding, with 2016's proposed budget cutting science funding by 37%. Three ministers had been appointed to run the science ministry in the past 16 months.

Using vibrations from ocean waves to measure ice-sheet mass

13 May 2016

The Economist: Predicting sea-level rise due to melting ice sheets is complicated because of the difficulty in measuring the changing masses of the ice. Currently the mass is measured with laser topography and gravitational fluctuations, but those methods are limited by cost and resolution. Now Aurélien Mordret of MIT and his colleagues have developed a technique that uses seismometers to measure the vibrations created by ocean waves striking near ice sheets. The vibrations travel at different speeds depending on the compression of the rocky crust from the ice above. Mordret and his team predicted that the vibration speeds they would measure during the winter, when Greenland's ice sheet is largest, would be different from those measured in the summer, when the sheet is smallest. Using seven monitoring stations throughout 2012 and 2013, the researchers found that their calculations were in line with measurements made using other techniques. Mordret says that expanding the network of seismometer stations in Greenland and elsewhere could give a much clearer picture of changes in ice-sheet mass.

Star’s mysterious dimming continues to confound astronomers

13 May 2016
Atlantic: A star spotted by the Kepler space telescope has provoked a certain amount of controversy. The star caught the attention of astronomers who noted an unusual series of dips in the light it emits. Such dips can indicate the transiting of a planet or the presence of a disk of dust and debris. However, after several years of study, researchers have ruled out those two possibilities. One suggestion, which has received a fair amount of attention, is that it is an alien megastructure built to harvest starlight. More pragmatic explanations include the presence of a family of comets circling the star. To better understand the star's unusual behavior, a worldwide effort is being mounted to monitor it over the next several years with a series of professional telescopes.

Soft surfaces lift hard objects

12 May 2016
The inclined plane experiment yields quite different results in a soft-matter setting.

Micrometeorites reveal oxygen in Earth's atmosphere earlier than thought

12 May 2016

New Scientist: A collection of 60 micrometeorites found in Australia reached Earth 2.7 billion years ago, which makes them the oldest known surviving meteorites. Andrew Tomkins of Monash University and his colleagues were surprised to find the micrometeorites to begin with; the fact that the rocks contain iron oxides is rewriting part of Earth's early history. The oxides most likely formed as the meteorites passed through Earth's upper atmosphere. The meteorites landed in a highly alkaline lake, which was completely anoxic at the bottom, and got preserved in layers of limestone. Scientists believe Earth's atmosphere at that time had very low levels of oxygen, but all the supporting evidence is limited to the lower atmosphere. Several theories suggest that the upper atmosphere may have been oxygen-rich due to solar radiation splitting molecules of water, carbon dioxide, and sulfur dioxide.

Collider made for quasiparticles

12 May 2016

Science News: Particle colliders have been a standard part of the physicist's toolkit for around 100 years, with different kinds of colliders being created for different kinds of particles. Now, Rupert Huber of the University of Regensburg in Germany and his colleagues have developed a collider that smashes electrons into quasiparticles known as holes. A hole is a void that is formed by the absence of an electron in a sea of electrons and that behaves like a particle. Huber's group created pairs of electrons and holes in tungsten diselenide with a short pulse of light and then applied an oscillating electric field. The field pulled the electrons and holes apart and then slammed them back together at several thousand kilometers per second. The collision results in the emission of light, which Huber's team analyzed to measure the energy required to separate the electron–hole pair. Huber says the information could be useful for improving solar cells, which collect the energy from the separation of electron–hole pairs generated by sunlight.

arXiv considering overhaul for its 25th birthday

12 May 2016

Wired: Established as a site for scientists to share and discuss their work before publication in peer-reviewed journals, arXiv now stores more than 1 million scientific papers and supports more than 125 million downloads per year. But the site's front-facing design has not changed much over the past 25 years, and its back end is running on a lot of legacy code, so site operators are planning on some refurbishment. In April arXiv asked users for design and functionality requests. The survey also asked whether the site should change how it handles checking the quality of uploaded papers and whether it should allow users to directly comment on and annotate papers. Any of these changes could significantly alter how the site, often viewed as a bastion of open-access research, fits into the larger realm of scientific publishing.

NASA's 747 makes first measurement of Martian oxygen since 1970s

12 May 2016

Ars Technica: In the 1970s NASA's Viking lander found that Mars's atmosphere was 95% carbon dioxide, with only minuscule levels of the nitrogen and oxygen that are a significant part of Earth's atmosphere. Over the past 40 years, no subsequent measurements of those trace gases in the Martian atmosphere have been made. Now NASA's Stratospheric Observatory for Infrared Astronomy (SOFIA) has taken a look at Mars's upper atmosphere, where it measured levels of oxygen that were about half of what Viking measured. SOFIA is a Boeing 747 that is specially modified to fly at an altitude of 45 000 ft (13.7 km) and is equipped with a highly sensitive spectrometer that enables measurements in the far-IR. The SOFIA team says the lower-than expected oxygen levels are likely the result of an uneven distribution of the gas in the atmosphere caused by localized releases of oxygen from chemical reactions in the Martian soil.

Hurricane forecasts will be different this year

12 May 2016
Extra Dimensions: Remembering William Gray, the charismatic and controversial tropical meteorologist who invented the seasonal hurricane forecast.

Carbon dioxide emissions are down in the US as fracking increases

11 May 2016
Movement away from coal reduces CO2 output and fuels a surge in hydraulically fractured oil and gas production.

Affordable virtual reality headsets are becoming valuable research tools

11 May 2016
Nature: Because of the proliferation and growing sophistication of video games and other commercial applications, virtual reality (VR) headsets have improved in quality and dropped in price. As a result, they are becoming much more affordable to not just individual users but also research laboratories. Already, researchers have used VR to treat a number of human psychological conditions, such as paranoia and claustrophobia, by virtually exposing patients to the source of their problem, like a crowded elevator or an underground train. Also gaining ground is a related technology called augmented reality, which superimposes images into a real-time environment rather than replacing the real world with a simulated one.

Questions and answers with Michael E. Mackay

11 May 2016
The materials science researcher has written his text as a general introduction to solar-energy utilization and an inspiration for new photovoltaic technologies.

Five islands have disappeared as Pacific sea levels rise

11 May 2016

BBC: The Solomon Archipelago is a lightly populated chain of islands in the South Pacific Ocean. A survey of aerial and satellite images collected between 1947 and 2014 has revealed that five of the islands have been swallowed by the ocean through a combination of rising sea levels and erosion. The islands were vegetated reefs that were unpopulated and relatively small—the largest was only 12 acres (0.05 km2). However, larger, populated islands are also being damaged. One of them, Nuatambu, has lost half its inhabitable area and 11 houses since 2011. The study notes that although the islands have seen sea levels rise as much as 10 mm/year over the last two decades, extreme weather events and inappropriate development are also responsible for some of the damage.

Obama to make symbolic visit to Hiroshima

11 May 2016
New York Times: When President Obama travels to Hiroshima, Japan, on 27 May, he will become the first sitting US president to visit the first city targeted by a nuclear weapon. Hiroshima was devastated by the atomic bomb the US dropped on 6 August 1945; it killed more than 100 000 people and caused widespread destruction. More than 70 years later, the city has been rebuilt and features the 30-acre Peace Memorial Park, which is among the sites Obama plans to visit. Rather than focus on the past, the president intends to direct attention to the future and his efforts to limit nuclear weapons around the world. That sentiment has been echoed by Japan’s prime minister, Shinzo Abe, who has said the visit will be a chance to both honor the dead and lend support to worldwide nuclear disarmament.

<em>Kepler</em> finds 1284 more exoplanets

11 May 2016

Los Angeles Times: On 10 May, the team running NASA's Kepler space telescope announced that the spacecraft had identified another 1284 extrasolar planets, which brings the total number to 2325. The majority of the newly discovered planets are super-Earths or mini-Neptunes—both defined as planets roughly 1.25 to 10 times the mass of Earth. Nine of the planets orbit in the habitable zone of their parent star. The new planet haul resulted not from more data but from a new algorithm that determined how likely a signal detected by Kepler was a planet rather than a false positive. The algorithm was applied to the full dataset of 4302 candidate planets identified by the telescope, including the 984 previously confirmed exoplanets. The algorithm correctly identified the previously confirmed planets and pulled out the 1284 other signals that the team presented.

Earth’s ancient atmosphere may have been much thinner

10 May 2016
New Scientist: The atmosphere on Earth some 2.7 billion years ago may have been less than half as thick as it is today. That finding is based on a new study in which Sanjoy Som of NASA’s Ames Research Center and colleagues looked at gas bubbles trapped in ancient lava covering thousands of square kilometers in the Australian outback. By comparing the larger bubbles that rose to the top with the smaller ones that got trapped at the bottom, the researchers were able to determine that the air pressure billions of years ago when the lava hardened was probably 0–0.5 atmospheres; the best estimate is that the atmosphere was 23% as thick as it is today. That finding contradicts earlier theories that said the atmosphere must have been thicker to prevent Earth’s surface from freezing over when the Sun was much younger and fainter. The researchers say the key may be nitrogen, which might have dominated the primeval atmosphere, warming it and fueling nascent microbial life.

Space agencies develop plan for network of emissions-tracking satellites

10 May 2016
New York Times: The space agencies of China, France, India, the US, and several other countries have distributed a draft of a plan that calls for six to eight satellites to map carbon dioxide emissions with enough precision to identify individual nations as the source. The satellite array, which is estimated will cost $5 billion and be in orbit by 2030, would be similar to the network of satellites that monitors cloud cover. The ability to measure the emissions contributions from individual countries would be a major improvement over the current system of self-reported values based on surface readings, economic analyses, and ecological estimates. In the current system, established in 1992, industrialized nations report yearly but developing nations only have to report occasionally. However, in the 2000s, emissions from developing nations surpassed those of industrial nations and currently are estimated to be 60% of the annual global emissions total.

<em>LRO</em> team asks NASA to extend mission another two years

10 May 2016
Science News: Launched in 2009 for a one-year expedition to study the Moon, the Lunar Reconnaissance Orbiter (LRO) has had its mission extended repeatedly over the last seven years. Mission researchers have completed the primary goals of scouting potential future landing sites for astronauts, looking for water, and probing radiation hazards. LRO is now the longest-lived lunar orbiter, and the team hopes to add at least two more years. Over its extended mission LRO has watched three other spacecraft crash into the Moon's surface, mapped numerous craters, spotted water ice covered by the Moon's regolith, and found evidence of past volcanic activity.

Magnetically levitated, tube-based transportation system would travel at rocket speed

10 May 2016
IEEE Spectrum: Passive magnetic levitation is the key to a proposed next-generation high-speed mass transit system. Hyperloop Transportation Technologies (HTT), a startup based in Southern California, is working on the concept with scientists from Lawrence Livermore National Laboratory, where the technology was first developed. The HTT system would consist of a magnetically levitated capsule that travels at the speed of sound inside a reinforced vacuum tube laid atop pylons. Levitation is achieved by lining the bottom of the capsule with a Halbach array of permanent magnets and running it over a railbed of electromagnetic coils. Such a system could cut travel times between major cities significantly. According to the HTT website, commuters would be able to go from New York City to Washington, DC, in just half an hour. Said to be cheaper and safer than active magnetic levitation systems, such as MagLev, which require power stations along the track, the HTT system is one of several levitated trains currently in development.

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