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Updated: 2 hours 59 min ago

NASA group to conduct snow census from the air

6 April 2016
Nature: Although snowfall is important for replenishing an area’s water resources, it has proven difficult to accurately measure because of the variety of landscapes it covers, such as mountains, prairies, and tundra. To come up with better measurement and modeling techniques, NASA has been developing SnowEx, an experiment that uses aircraft equipped with radar, lidar, and other remote-sensing instruments to measure snow cover. Starting this fall, the sensors will be tested simultaneously over various sites in North America to see which combination is most effective. The project may expand beyond the continent in future years. The ultimate goal is to build a snow-sensing satellite fitted with the best combination of sensing technologies. Scientists want more accurate information on snowfall and the expected melt and runoff connected to climate change.

Space station to add inflatable room

6 April 2016
New Scientist: The astronauts on the International Space Station (ISS) are about to get a new room. An inflatable module is scheduled to be launched on 8 April as part of a SpaceX resupply mission. Made of a soft, foldable fabric, the Bigelow Expandable Activity Module (BEAM), developed by Bigelow Aerospace, will be packed into the trunk compartment of the Dragon spacecraft. Once in orbit, the fabric will be attached to node 3 of the ISS and allowed to expand. Over the next two years, BEAM will remain unoccupied but will be monitored for pressure and temperature, radiation protection, and potential deterioration from meteoroid or debris impacts. Astronauts will also periodically enter the module and inspect it. If the technology works, Bigelow hopes to use it for larger projects, such as a private space station or space hotel.

White House highlights water R&D needs

5 April 2016
Dozens of US universities and private-sector entities join federal agencies to mark World Water Day.

SLAC particle accelerator to add second x-ray laser

5 April 2016
Ars Technica: SLAC National Accelerator Laboratory, the most powerful x-ray source in the world, has announced it is undertaking a $1 billion upgrade in partnership with four other national labs and Cornell University. SLAC plans to add a second x-ray laser that will be 10 000 times as bright and fire 8000 times as fast as the existing Linac Coherent Light Source. Whereas LCLS generates 120 laser pulses per second by accelerating electrons down a copper pipe, LCLS-II is expected to achieve one million pulses per second by the addition of a superconducting accelerator. Designed to work in parallel, the two lasers will allow researchers to make more detailed observations of samples and to gather data more quickly.<

DNA used to craft world's smallest diode

5 April 2016

IEEE Spectrum: Diodes are electrical components that allow electricity to flow in only a single direction. Now a diode has been made from an 11-base-pair length of DNA combined with two molecules of coralyne. The combined molecule, which is roughly 4 nm long, allows electrical current to flow through it 15 times as strongly in one direction as in the other. The researchers believe that the coralyne molecules fuel the one-way movement of electricity by creating an imbalance in the distribution of electrons in the DNA.

Blue Origin rocket completes another launch and landing

5 April 2016
Wired: On 2 April, private aerospace company Blue Origin completed another successful launch of its New Shepard reusable spacecraft. This time the company was testing its BE-3 engine, which needs to start fast and provide high thrust in order to slow the craft as it returns for landing. After soaring to a height of 103 km, the rocket returned to its launch site in western Texas, where the BE-3 kicked in 1000 m—and just 6 seconds—above the ground and slowed the craft to less than 5 mph for landing. If future test flights are as successful as this one, Blue Origin CEO Jeff Bezos says the company could start offering suborbital tourist spaceflights on New Shepard as early as 2018.

Sea-level rise threatens NASA facilities

5 April 2016
New York Times: NASA owns about $32 billion worth of structures and facilities in the US. Roughly two-thirds of the land it manages is within 4.8 m of mean sea level—including Johnson Space Center in Texas, Michoud Assembly Facility in New Orleans, Ames Research Center near San Francisco Bay, and, of course, Kennedy Space Center in Florida. According to the agency's Climate Adaptation Science Investigators working group, sea-level rise by 2050 could cause those facilities significant problems, including regular flooding and increased damage from hurricanes. The agency has already spent $3 million repairing protective dunes around Kennedy Space Center, but longer-term plans for relocating and protecting facilities will likely reach into the billions.

Martian dust devils may get a boost from their own shadows

4 April 2016

New Scientist: Due to Mars's thin atmosphere, dust devils require strong winds to keep the sand grains swirling off the ground. Gerhard Wurm of the University of Duisburg-Essen in Germany suggests that the temperature difference between shadowed and sunlit ground may be enough to kick extra dust into the air. To test his theory, he dropped a capsule full of Mars-like sand down a 110 m drop tower, shined a laser light on the dust as it fell, and measured the dust grains as they bounced around inside. When Wurm switched off the laser, he noted that the grains' movement increased by a factor of 10, which he attributed to the cooling of the dust. He says that on Mars the dust devil's shadow could have a similar cooling effect. The resulting temperature changes could cause gases in the Martian soil to move around and, after a buildup of pressure, explode and lift sand into the air. That feedback effect could fuel the large dust storms occasionally seen on Mars.

Using light to transfer heat between objects

4 April 2016
IEEE Spectrum: Besides conduction and convection, a third option for transferring thermal energy is light. Although once thought too weak to be useful, heat transfer via radiation works well when the two objects transferring energy are placed close together, say Michal Lipson of Columbia University and her colleagues. Despite the difficulty involved in maintaining large thermal gradients over nanometer-scale distances, the researchers have succeeded by using high-precision microelectromechanical systems to separate nano-sized beams of silicon carbide. When the SiC beams were spaced 42 nm apart, the researchers achieved a heat transfer almost 100 times as strong as that predicted by conventional thermal radiation laws. The technology could have many uses, including converting the waste heat in a car’s combustion engine to electricity and controlling the temperature of delicate nanodevices.

China’s greenhouse gas emissions may be slowing

4 April 2016
New York Times: China, the world’s largest greenhouse gas emitter, appears to be making progress in its efforts to reduce its emissions and transition to more renewable energy sources. According to official energy data, Chinese emissions dropped 1–1.5% last year from 2014. The reason may be China’s efforts to cut its coal use and switch from an energy-intensive economic model based on heavy industry to a more sustainable one, say Fergus Green and Nicholas Stern, whose paper was published recently in Climate Policy. However, some doubt has been expressed concerning Chinese energy statistics, which are frequently revised and often unreliable, according to another study, published in Nature Climate Change. “I would be more confident to say that China has reached a plateau or period of low growth,” says Glen Peters, one of the coauthors of the Nature paper.

LIGO may soon be able to detect murmurs from distant black hole collisions

4 April 2016
Science News: When researchers at the Advanced Laser Interferometer Gravitational-Wave Observatory (LIGO) announced that they'd found the first direct evidence of gravitational waves from the collision of two black holes, the source of the signal was calculated to be roughly 1.4 billion light-years away. There was no mistaking the characteristic signal because of how clearly it stood out from the background noise. Now the LIGO team members say that they may be able to tease out evidence of much more distant collisions from those background fluctuations. The researchers hope to compare the background data recorded by the two LIGO detectors and identify matching patterns. Because black hole mergers seem to occur more frequently than previously thought, LIGO could be able to detect as many as 2000 mergers per year.

Coherence in a crowd of molecular-spin qubits

4 April 2016
By finding a way to reduce decoherence in relatively dense collections of tiny molecular magnets, researchers have enhanced their prospects as carriers of quantum information.

John Cahn

1 April 2016

Climate change is forcing some bird species farther north

1 April 2016
Washington Post: American robins and European wrens are among the many animal species that are shifting habitat because of climate change. Global temperatures have been rising markedly since the Industrial Revolution, and the period from December 2015 to February 2016 saw some of the highest average temperatures since record keeping began in 1880. Many birds have been moving farther north to compensate for the temperature difference. To better understand the effects of climate change on various species, Stephen Willis of Durham University in the UK and colleagues studied climate records from 1980 to 2010 and followed population trends for some 145 common European bird species and 380 American bird species. They found not only that some species handle climate change better than others, but that when a species is forced to move, it leaves a void in the old habitat and creates competition in the new one.

Baja California’s desert mangroves are important carbon sink

1 April 2016
Los Angeles Times: Mangroves, which populate tropical forests and coastal areas, may provide a valuable carbon sink, according to a recent study by Paula Ezcurra of the Scripps Institution of Oceanography and colleagues. Not only do mangroves draw carbon dioxide from the atmosphere, but when they decay, the CO2-rich plant residue accumulates in peat bogs, burying the carbon underground for thousands of years. The researchers, who focused on the desert mangroves of Baja California, say that despite those mangroves’ short and stunted appearance, they may be able to sequester even more carbon dioxide from the atmosphere than the lusher mangroves that grow in tropical areas. “Mangroves represent the largest carbon sink per unit area in Mexico’s northern drylands,” write the researchers. But humans are destroying mangrove forests at a rate of 3% every year.

When tornadoes and flash floods occur simultaneously

1 April 2016
Forecast and communication challenges are compounded when the two extreme events coincide.

Laser could be used to hide a planet transiting its star

1 April 2016

New Scientist: Assuming a distant star is aligned with Earth's orbital plane, inhabitants of that star system would see Earth transiting the Sun for about 10 hours per year. According to David Kipping and Alex Teachey of Columbia University, a 30 MW laser pointed at that star from Earth would be able to mask evidence of the transit, hiding Earth from any aliens looking for exoplanets. Alternatively, the researchers say that the same laser could be used to warp the sunlight in a way that would act as a signal to indicate the presence of intelligent life on Earth. Kipping and Teachey now want to look through data collected by the Kepler space telescope to see if any aliens have arrived at the same idea of trying to cloak or amplify transit signals.

White dwarf has an atmosphere that is almost completely oxygen

1 April 2016
Popular Mechanics: There are only about 32 000 known white dwarf stars, and now one of them has been revealed to be unique among all known stars. Discovered by Kepler de Souza Oliveira of the Federal University of Rio Grande do Sul in Brazil and his colleagues, the star, which they dubbed Dox, has an outer atmosphere that is 99.9% pure oxygen. In comparison, Earth's atmosphere is only 21% oxygen. Normal white dwarfs have atmospheres made primarily of lighter elements, the remnants of the stars' original material. The researchers say the dwarf star may have been part of a binary system with a Sun-like star. Dox could have siphoned off material from the neighboring star and then exploded as a supernova, expelling the lightest elements and destroying its partner. The mystery is why only oxygen would have been left behind.

Thermal surface map of super-Earth obtained for first time

31 March 2016

Scientific American: Discovered in 2004, the super-Earth 55 Cancri e was thought to be a large rocky world with a thick, hot atmosphere. By mapping thermal changes of the planet's surface using the Spitzer Space Telescope, Brice-Olivier Demory of the University of Cambridge and his colleagues have now found that the planet is likely airless. The scientists discovered that the planet is tidally locked with its parent star, meaning that one side is perpetually covered in sunlight. The data from the telescope showed that the dark side of the planet reached temperatures of 1000 °C and that the lit side was more than twice as hot. If the planet had an atmosphere, winds would distribute the heat more evenly and minimize the temperature difference. However, the hottest spot on the planet is not directly in line with the star, suggesting that something is redistributing the heat. Demory's team believes that the hot spot, which is shifted eastward, is most likely caused by the movement of molten lava circulating heat from the dayside surface toward the nighttime one, where it cools and solidifies.

New gravimeter built using smartphone accelerometers

31 March 2016

BBC: Gravimeters, which are used to measure local variations in gravity, are generally large and cost about $100 000. Now Richard Middlemiss of the University of Glasgow, UK, and his colleagues have developed a cheap, postage stamp–sized gravimeter based on the tiny accelerometers commonly found in smartphones. The new gravimeter employs a block of silicon suspended between two thin bands. As gravity pulls the block downward, the block's shadow—cast by light shining through the device—also moves and that movement is detected by a photodiode. Researchers can calculate the strength of the gravitational pull by measuring the amount of current the light-sensitive diode produces. The team tested the device by measuring Earth's tides over the span of several days. The device was more than sensitive enough to detect the changes in gravity due to tidal forces; it could also detect variations as small as those caused by a 1 m diameter tunnel located 2 m below ground. Distributing a network of the small gravimeters around a volcano could provide continuous localized monitoring for a fraction of the cost of a conventional gravimeter.

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