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Updated: 1 hour 36 min ago

Los Alamos contract extended for another year

18 May 2016
US Department of Energy needs more time to choose new contractors at both its New Mexico national laboratories.

Elsevier purchases major preprint server

17 May 2016

Nature: Online preprint servers, such as arXiv, allow researchers to publicly share their papers prior to peer review. The sites are growing in popularity because they provide free access to cutting-edge research, albeit in draft form. Journal publisher Elsevier, which has tried unsuccessfully to establish its own preprint server, has now purchased the Social Science Research Network, one of the most popular preprint servers for economics, law, and the social sciences. The move appears to be part of the publisher's larger effort to broaden its services in order to increase web traffic and protect its subscription-based journals.

Photons can have half-integer angular momentum

17 May 2016

Gizmodo: Aside from their wavelength, photons also have a measurable angular momentum that characterizes their rotation along their axis of travel. That value has always been observed to be some integer multiple of Planck's constant. Now Paul Eastham of Trinity College Dublin and his colleagues have manipulated photons so they have half-integer angular momentum. To do that, the researchers made use of a phenomenon first discovered in the 1830s: When light is passed through certain crystals, it creates a cylinder-like structure. Theoretical analysis of the system suggested that the resulting photons had half-integer angular momentum, and measurements proved the predictions correct. The team thinks that such photons could be used for encrypted light-based communications.

Spider silk's amazing elastic properties inspire hybrid liquid wires

17 May 2016
New Scientist: The capture silk that makes up the spiral of the orb-weaver spider’s web can be stretched like a spring and then compressed without sagging. According to a recent study by Arnaud Antkowiak of the Pierre and Marie Curie University in Paris and his colleagues, the spider’s silk is composed of a thread covered with glue droplets. Once thought to be used primarily for trapping insects, the glue droplets have a second purpose: They help keep the webbing taut. Unlike regular thread, which tends to sag after being stretched, the spider thread spools around the glue droplets. The researchers have now copied that molecular nanospring behavior by using plastic filaments coated with silicone oil and other liquids. The material could have several practical uses in robotics, microfabrication, and other technologies.

Lead traces in Italy's Bay of Naples provide insight into ancient Roman history

17 May 2016
Science: Sediment cores taken from the harbor of Naples, Italy, are being used to study Roman expansion in the area over a period of some 500 years. The cores show traces of various iron isotopes, which flowed into the harbor through the elaborate lead-pipe aqueduct system the Romans constructed. From the different isotopes, researchers have been able to determine where the lead was mined and thus start mapping out a timeline of urban development in the region. One discovery, reported in the Proceedings of the National Academy of Sciences, was a sudden shift in lead content about AD 79, when nearby Mount Vesuvius erupted. That shift suggests that the aqueduct pipes may have become damaged during the eruption and were subsequently repaired with lead mined from a different location. In addition, the researchers say that over time the lead came from sources increasingly farther from Naples, which indicates that the aqueduct network continued to expand for hundreds of years.

Hans Kleinpoppen

17 May 2016

Journalists, commentators join TV humorist John Oliver in condemning bad science reporting

16 May 2016
He declares: "We like fun, poppy science that we can share like gossip—and TV news producers know it!"

Getting up close and personal with military explosives

16 May 2016
An all-in-one instrument array dissects the detonations of TNT, C-4, and pentolite.

Key observing station reports 400 ppm for atmospheric carbon dioxide

16 May 2016

Science: The carbon dioxide monitoring station at Cape Grim, on the northwestern tip of Tasmania, recorded readings above 400 ppm for four consecutive days last week, according to Paul Krummel of Australia's Commonwealth Scientific and Industrial Research Organisation. That level stands in stark contrast to the baseline of 280 ppm for atmospheric CO2, the level at the beginning of the industrial age 200 years ago. Scientists estimate that a level of 450 ppm would correspond to a global temperature increase of 2 °C, the maximum increase allowable to avoid the most devastating consequences of global warming. Cape Grim isn't the first monitoring station to pass 400 ppm; an outpost on Mauna Loa in Hawaii reached that mark in 2013 and has occasionally done so ever since. Unlike the Mauna Loa station, the Cape Grim station is not as significantly affected by seasonal changes that cause regular rises and falls in CO2 levels. Cape Grim is also located at a latitude where strong winds perpetually blow, which prevents localized buildups of pollution. As such, measurements taken at the station are used as a proxy for global CO2 levels.

Most of the Great Barrier Reef has been damaged by coral bleaching

16 May 2016
NPR: About 93% of Australia’s Great Barrier Reef has been adversely affected by coral bleaching, according to recent aerial and underwater surveys by researchers at the ARC Centre of Excellence for Coral Reef Studies. Bleaching is a destructive phenomenon that results when corals, which are made up of living organisms, are stressed by environmental conditions and become unable to provide the algae living in them with the nutrients needed to perform photosynthesis. The bleaching event is the worst ever recorded, with just 7% of the reef having escaped bleaching entirely. The northern half has been the hardest hit, with 60–100% of the reef having been severely bleached. Although that area is the most remote and, until now, the most protected from human activities, global climate change has raised the temperature of the water, which has put undue stress on the corals. Whereas some of the damaged corals are expected to survive and regain their normal color, the event is indicative of the wide-scale bleaching of coral reefs that is going on around the world. The long-term effects on those diverse underwater ecosystems remain unknown.

Simons Foundation to build $40 million telescope for primordial gravitational-wave search

16 May 2016
Nature: The gravitational waves detected by the Laser Interferometer Gravitational-Wave Observatory were produced by the collision of two black holes. But models suggest that the universe is also flooded with ripples in spacetime that were created during the inflationary period that followed the Big Bang. Those ripples are expected to be detectable indirectly as B modes, patterns in the polarization of the cosmic microwave background (CMB) radiation. In 2014, the BICEP2 experiment reported finding B modes, but the signal was later shown to be the result of interstellar dust. To join the search, the nonprofit Simons Foundation has revealed plans to build a $40 million telescope in Chile's Atacama Desert. It will use around 50 000 detectors, about 10 times as many as the largest current B-mode telescopes. The presence of B modes in the CMB would offer strong evidence that some version of the theory of inflation is correct.

Large star swallowing smaller star demonstrates Darwin instability

16 May 2016
New Scientist: In January 2015 the Hubble Space Telescope captured images of a red nova, a star that suddenly brightened and then returned to normal, in the Andromeda galaxy. Brighter than novae but dimmer than supernovae, red novae occur when two gravitationally bound stars merge. As the stars come together, they expel gas that expands and cools, which makes the nova appear red. In the 2015 event, an extremely large yellow star ate a much smaller red one. The event was triggered by the Darwin instability, predicted by Charles Darwin’s son George almost 150 years ago, in which the spin of the larger star in a binary pair starts to slow over time and the smaller star eventually gets sucked in. Red novae are a relatively new class of variable star, with the first confirmed sighting in 2007.

Magnetic reconnection event monitored directly for the first time

13 May 2016 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.