News Picks

Physics Today’s online staff summarize the most important and interesting news about science from the world's top media outlets.

There are 87 posts for the selected month (June 2015).
June 30, 2015 2:36 PM

Unusual pulsar slowdown provides more clues about the stars

New Scientist: Pulsars are neutron stars whose rapid rotation forces beams of radiation from the poles. Over time, the rotation rate gradually slows, and the deceleration is dependent on the pulsar's age. Some older pulsars become intermittent, decelerating slowly while not emitting much radiation and then decelerating more quickly while emitting lots of radiation. Now, a relatively young pulsar has displayed the characteristic deceleration of those older pulsars. Frank Marshall of NASA's Goddard Space Flight Center in Greenbelt, Maryland, and his colleagues suggest that the star's magnetic field could be the cause. In intermittent pulsars, as the magnetic field shifts, it alternately traps plasma that releases radio waves and then releases it. Further observations are necessary to determine if the star is an intermittent pulsar, but studying it more closely is likely to provide more information about the behavior of pulsars in general.

June 30, 2015 1:57 PM

Hydrogen sulfide sets high-temperature superconducting record

Nature: Hydrogen sulfide, the colorless gas that smells of rotten eggs, has been coaxed into demonstrating a characteristic property of superconductivity at a record high temperature of 203 K (−70 °C). Last year, Mikhail Eremets of the Max Planck Institute for Chemistry in Mainz, Germany, and his colleagues had seen H2S superconducting below 190 K when compressed at 1.5 million atm. At such extreme pressures, the gas compresses into a solid crystal. Now, at a pressure of 2 million atm, the H2S exhibited a sudden increase in "magnetization signal" at 203 K. That increase occurs when the material prevents external magnetic fields from passing through it, a phenomenon known as the Meissner effect. Two other groups report that they have seen the same phenomenon but are waiting for Eremets's team to publish first. The previous highest superconducting transition temperature, 135 K, was obtained in 1993 in a layered cuprate material.

June 30, 2015 12:15 PM

Magnetic levitation of cells for sorting and diagnostics

Science: An innovative technique has been developed that uses magnets to levitate individual living cells. Utkan Demirci of Stanford University and colleagues added particles of gadolinium, a rare-earth metal, to a fluid in a channel positioned between two long, toothpick-sized magnets. The magnetic field pulls the Gd downward, which allows the cells to rise upward. How high the cells rise indicates their density with respect to the Gd. Because different types of cells levitate to different heights, the method could be used to distinguish cancer cells from blood cells, or red blood cells from white. The technique could also be used to monitor changes in cellular density and levitation due to antibiotic or cancer treatments.
June 30, 2015 11:20 AM

Today will be one second longer

BBC: Today, 30 June, timekeepers around the world will be adding one more second to the day, called a leap second. Leap seconds have been added periodically since 1972 to help keep the Coordinated Universal Time system running close to mean solar time, which varies because of Earth’s irregular rate of rotation. So far, 25 leap seconds have been added—the last exactly three years ago today. However, objections have been raised because of the problems the tiny correction causes for computer systems, which rely on precise timekeeping and must be reprogrammed manually to handle the irregular adjustments. The issue is to be discussed at the upcoming World Radiocommunication Conference in Geneva in November.
June 29, 2015 2:36 PM

Ice exists closer to Milky Way central black hole than expected

New Scientist: Over the years, ice and hydrocarbons have been spotted in interstellar space by telescopes pointed at the supermassive black hole in the Milky Way's center. Their presence was revealed by the absorption spectrum in the IR. It was assumed that they were located far from the galactic center, however, because the level of radiation near the central black hole is high enough to melt most ice and potentially destroy hydrocarbons. Now, Jihane Moultaka of the Research Institute in Astrophysics and Planetology in Toulouse, France, and her colleagues have revealed that some of that ice is quite close to the central black hole. To make that determination, they removed the signatures of ice and hydrocarbons from nearby regions of space. The leftover signals aligned with maps of galactic dust. Moultaka's team believes that the ice, which ranges in temperature from 10 K to 80 K, is sheltered by the dust particles. The presence of cold dust clouds suggests that stars can still form near the galactic center.

June 29, 2015 2:00 PM

South Asian heat wave perplexes climatologists

BBC: Last week more than 1000 people died in Pakistan and 2000 in India during the worst heat wave to hit South Asia in three decades. Although a high of 43 °C had been predicted in Karachi, Pakistan, the temperature felt more like 49 °C. Scientists working to understand the extreme weather event say an unfortunate series of factors came into play simultaneously: low air pressure, high humidity, and lack of wind. Changes in atmospheric circulation are to blame, but their cause remains unknown. Despite the warning of the United Nations’ Intergovernmental Panel on Climate Change that heat waves will increase in South Asia due to global warming, scientists say that heat waves have not been as intensely studied as other, more quickly evolving phenomena, such as cyclones and flooding, and so are not as well understood.
June 29, 2015 1:54 PM

Official count puts Earth's number of large impact craters at just 128

Science: Wind and water movement, tectonic activity, and other processes have continually eroded Earth's surface to a degree unseen on Mars or the Moon. As a result, there are far fewer impact craters visible on Earth's surface compared with the 300 000 on Mars and the uncountable millions on the Moon. In 2014, it was determined that all the craters on Earth with a diameter larger than 85 km had been discovered. Now, Stefan Hergarten and Thomas Kenkmann of the University of Freiburg, Germany, have extended that down to all craters larger than 6 km across. The determination that no more large craters will be found is based on impact and erosion rates, theoretical crater distribution, and the number of craters actually found. Hergarten and Kenkmann go on to suggest that only about 350 craters between 0.25 km and 6 km in size remain to be discovered.

June 29, 2015 11:30 AM

SpaceX ISS resupply rocket explodes after liftoff

Nature: Yesterday an unmanned SpaceX Falcon 9 rocket exploded about 139 seconds after launch. It was the seventh ship launched by the US aerospace company under its contract with NASA to carry supplies to the International Space Station (ISS). Although the cause of the explosion is under investigation, preliminary analysis revealed a potential problem with the upper-stage liquid oxygen tank, according to SpaceX CEO Elon Musk. It was the third resupply mission to the ISS to fail within the past nine months. Another US rocket, launched by Orbital Sciences, exploded during launch last October, and a Russian spacecraft lost control after launch in April. Although the SpaceX vehicle carried more than 2 tons of goods, including food, the three astronauts onboard the ISS still have about four months’ worth of supplies. The next supply mission will be a Russian Progress rocket scheduled to launch on 3 July, and Japan has a mission planned for August.
June 26, 2015 1:55 PM

Humans found to have greater lateral vision than other apes

New Scientist: Of the members of the ape family, humans have the widest field of view, a distinction due to the shape of their skull. In a study of 100 human skulls and 120 ape skulls—30 each of gibbons, orangutans, gorillas, and chimpanzees—researchers found that human eye sockets are much wider and the outer margin is recessed much farther back in the skull. That configuration allows humans an unimpeded sideways view through eye movement alone without the extra effort of moving one’s head. Whether the trait evolved to give humans an advantage, such as in the detection of predators, or whether it was the result of other changes to human morphology, such as the shrinking of the chewing muscles as humans ate more cooked food, is unknown.
June 26, 2015 12:53 PM

Last part of New Horizons mission to Pluto will be the hardest

Nature: On 14 July, NASA's New Horizons spacecraft is scheduled to make its first flyby of Pluto. Pluto's orbit has never been fully mapped because it hasn't completed an orbit since it was discovered. The fact that no one knows Pluto's exact location combined with the 9-hour communication lag between New Horizons and Earth means the craft will be essentially approaching the dwarf planet blind. During the flyby, the craft has to pass through a window of space just 100 km by 150 km. The targeted path is only 12 500 km above Pluto, and the spacecraft will be moving nearly 14 km/s. The last chance for mission navigators on Earth to signal New Horizons for a change of course will be 4 July. As the craft approaches Pluto, it is taking daily pictures of the planet, which allows the people guiding it to more accurately calculate Pluto's position against the background stars. But they still haven't been able to get an accurate measurement of the distance to the dwarf planet.

June 26, 2015 10:47 AM

Improvement overcomes signal loss in fiber-optic cables

New York Times: To prevent signal degradation, current fiber-optic cables have to convert the signal from light to electricity and back to light roughly every 97 km . Now, Nikola Alic of the University of California, San Diego, and his colleagues have transmitted a fiber-optic signal 12 000 km without having to regenerate the light. In their paper, which does not cover that achievement, they explain that they used specially pulsed laser light to limit the amount of distortion that the light experiences within the cable as a result of a nonlinear response known as the Kerr effect. That allowed the team to increase the strength of the transmission lasers 20-fold. If the technique can be applied to real-world situations, it could drastically increase data transmission rates while also decreasing the costs of fiber-optic networks.

June 26, 2015 10:30 AM

Protests resume over giant telescope project on Mauna Kea

Science: On Wednesday activists on Mauna Kea in Hawaii resumed protests to block construction of the proposed 18-story Thirty-Meter Telescope. Protesters have expressed concern over the number of telescopes there already, and they cite a history of mismanagement of the site by the state government and the University of Hawaii, which holds the lease. Protests started in October 2014 at the groundbreaking ceremony and came to a head in April, when Hawaii state governor David Ige halted construction to allow further dialog. On 20 June it was announced that an agreement had been reached, which included accelerating the removal of several of the 13 telescopes already on Mauna Kea. Nevertheless, when crews showed up on 24 June, they found the road blocked by protesters; according to Andre Perez of the Oahu-based Movement for Aloha No ka Aina, a “major confrontation” ensued, in which 11 people were arrested.
June 25, 2015 3:00 PM

Proposed OneWeb global satellite network acquires 60 rocket launchers

BBC: An ambitious satellite project to provide global internet service recently acquired 60 rocket launchers. Virgin Galactic’s Richard Branson has promised at least 39 LauncherOne rockets to the OneWeb satellite network, and the European multinational Arianespace will provide another 21 Soyuz launchers. The Russian-made Soyuz rockets are capable of launching as many as 36 satellites at a time. Despite numerous high-level business partners, including European aerospace giant Airbus, Coca Cola, and Intelsat, OneWeb is still raising the necessary funds and trying to lower the cost of each of the some 700 satellites that will eventually form the network.
June 25, 2015 2:40 PM

Nobel laureate is Australian National University's new chief executive

Sydney Morning Herald: Astrophysicist Brian Schmidt has been named the next vice-chancellor of the Australian National University, where he has been employed for the past two decades. He will replace Ian Young, who is retiring at the end of the year. Among his many accomplishments, Schmidt was awarded the 2011 Nobel Prize in Physics “for the discovery of the accelerating expansion of the Universe through observations of distant supernovae.” The US-born Schmidt says he plans to work to improve research and educational opportunities; increase the university’s collaborations with businesses, government, and other institutions; and connect with alumni all over the world. "I really want to give back to the university that has given so much to me," he said.
June 25, 2015 2:20 PM

Giant hydrogen cloud trails distant super-Earth

Los Angeles Times: Astronomers studying a Neptune-sized exoplanet have discovered that it is surrounded by an enormous cloud of hydrogen gas. As the planet Gliese 436b, about 30 light-years from Earth, closely orbits its red dwarf star, the planet's atmosphere burns off and the cloud is created, along with a trail of gas that forms a comet-like tail. Astronomers discovered the giant gas cloud by using the Hubble Space Telescope to observe the planet’s transit as it crossed in front of its star. Although invisible at optical wavelengths, the cloud blocked more than 50% of the star’s UV radiation. Just four times the size of Earth, Gliese 436b is of interest to astronomers searching for smaller, more Earth-sized planets in order to better understand their origin and, hence, that of Earth.
June 25, 2015 11:50 AM

New climate-change study focuses on extreme weather

Nature: Besides monitoring changes in atmospheric circulation, climate scientists should also concentrate on the underlying causes of extreme weather, according to a new study published in Nature Climate Change. Kevin Trenberth of the National Center for Atmospheric Research in Boulder, Colorado, and colleagues used particular weather events—such as Hurricane Sandy, which struck the US East Coast in October 2012—to illustrate how changes in the climate system’s thermodynamic state can affect a storm’s intensity. By modeling the storm and varying the sea-surface temperature, the researchers found that the warmer waters caused by climate change boosted the storm’s size and strength by increasing the amount of water vapor and precipitation. Even a small change “can make a big difference,” says Trenberth.
June 24, 2015 1:25 PM

Dutch government loses key climate case

New Scientist: The government of the Netherlands has lost a class action suit concerning climate change. The suit was brought by an environmental group called Urgenda, which claimed that the government's plans to cut greenhouse gas emissions were not ambitious enough and that its citizens were put in danger as a result. The ruling was based on the recommendation of the Intergovernmental Panel on Climate Change that by 2020 governments cut emissions by at least 25–40% compared with 1990 levels. The Netherlands had opted for just 14–17%. The court ordered the Dutch government to achieve at least 25% by 2020. That governments have a legal obligation to cut emissions and safeguard the climate was a key point in the proceedings.
June 24, 2015 1:20 PM

Gullies in Mars crater suggest liquid water flow in recent past

Los Angeles Times: Water may have flowed freely on Mars as recently as within the last million years, according to a study published in Nature Communications. Using the HiRISE camera on NASA’s Mars Reconnaissance Orbiter, researchers mapped the well-defined gullies of Istok crater and compared them with gullies on Earth. They found that carving the distinctive tracks would have required frequent debris flows with about 20% to 60% water content about every 10 to 100 years. The researchers explain the change in Mars’s liquid water content by the fact that the planet's axial tilt has shifted over time, between 15 degrees and 35 degrees. When the planet is tilted more sharply, the Sun may cause ice at the poles to sublimate and drive the water cycle. Whether there are more craters like Istok is unknown, but the possibility of abundant water in Mars’s recent past could mean that microbial life also existed there.
June 24, 2015 12:07 PM

Jill Hruby becomes first woman to run US nuclear weapons lab

Science: On Monday, Jill Hruby was named Sandia National Laboratories' new director. Hruby will be the first woman to lead one of the US's three nuclear weapons labs. As the head of Sandia, Hruby will oversee much of the country's R&D focused on maintaining and upgrading the country's nuclear arsenal. Hruby, who has worked at Sandia for the last 32 years, will take over for Paul Hommert on 17 July. Sandia has a lower profile than its counterparts at Los Alamos National Laboratory and Lawrence Livermore National Laboratory, but is considered by the Department of Energy to be the best managed of the three facilities.

June 24, 2015 12:06 PM

Nearly 1000 more hard-to-spot galaxies found

Daily Beast: Earlier this year, 47 galaxies with certain similarities were found in the Coma Cluster. They are all nearly as large as the Milky Way but have only as many stars as dwarf galaxies and almost no gas, which makes them hard to detect. Now, 854 more of these "ultra diffuse galaxies" (UDGs) have been found in the same area, near the heart of the Coma Cluster. Despite the galaxies' low density of stars and gas, their structures are similar to those of normal galaxies, which suggests they have an abundance of dark matter. However, until the galaxies' mass can be measured, that cannot be confirmed. Whether UDGs are present in all galaxy clusters or only in old, large ones like the Coma Cluster is still an open question as well.

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Scitation: News Picks - Blog