Physics Today Daily Edition

Subscribe to Physics Today Daily Edition feed
New content is now available online. Please follow the links to view the content.
Updated: 1 hour 54 min ago

Next-generation memory chip packs in the data

4 hours 35 min ago

MIT Technology Review: As demand for data storage grows for increasingly small devices such as smartphones, companies have been working on a new type of memory chip that can store much more data in a much smaller space. Resistive random access memory (RRAM) stores bits of information using resistance in a transistor. It shows promise of being much denser and faster than flash memory, which stores bits using electrical charge. Now a group of researchers at Rice University has developed a way to make RRAM that avoids the high temperatures and voltages required by previous efforts. Their chip is made by inserting a layer of porous silicon oxide between two thin layers of metal. When a voltage is applied, a conduction path forms through the silicon. The presence or absence of such paths can be used to represent the 0s and 1s of binary digital data. To rewrite the bits, they apply another electrical pulse. Once perfected, RRAM could store one terabyte of data on a device the size of a postage stamp.

"Almost destroyed world"? Journalists planetwide report danger from the sun

7 hours 47 min ago
Scientists warn "we should waste no time" in learning from a powerful coronal mass ejection.

Drought in western US leads to groundwater depletion

8 hours 55 min ago

Nature: Because of a 14-year drought, demand for water by communities in the Colorado River Basin may soon exceed supply. To keep reservoirs filled and crops irrigated, people have been pulling water in unprecedented amounts from reserves underground. According to data from the Gravity Recovery and Climate Experiment (GRACE) satellite mission, which can measure the mass of water over the entire region, some 50 trillion liters of groundwater has disappeared. “It was way more than we ever thought,” says Jay Famiglietti of NASA’s Jet Propulsion Laboratory in Pasadena, California, and a coauthor of a study published in Geophysical Research Letters. The research team is now working to produce higher-resolution data to help better manage local water supplies.

Ancient rock yields clues to early oxygen “oases” on Earth

28 July 2014

New Scientist: Early Earth had no oxygen. However, at one point, oxygen-rich pockets of seawater may have started to form due to bacteria living in shallow, nutrient-rich marine areas. The oxygen then reacted with dissolved iron to form rock, which sank to the ocean’s bottom. The removal of the iron from the seawater allowed calcium carbonate to build up and form limestone. That geologic progression can be seen in rock samples from Steep Rock Lake in Ontario, Canada. They contain a mixture of iron minerals and limestone and layers of microbes, which are some 2.8 billion years old. Although such oxygen oases persisted for only about 5 million years, they forced early life forms to adapt to the chemically reactive gas before it would eventually spread around the world. Thus that period was a critical moment in the evolution of life on Earth, according to Robert Riding of the University of Tennessee and colleagues, whose study was published in the journal Precambrian Research.

An all-optical quantum router

28 July 2014
A new single-photon switch moves researchers a step closer to realizing large-scale quantum networks.

Starling flocks’ smooth flight paths likened to fluid flow

28 July 2014

Science: The collective motion of a flock of starlings in flight has now been studied in depth, thanks to high-speed cameras, tracking software, and mathematical modeling. Watching video of flocks of the birds flying around a train station, researchers were able to pinpoint which individuals decided to turn and then watch the way directional change swept through the rest of the flock. The researchers found that decisions to change direction travel through a flock at a constant speed, which allows the birds to turn in near unison. It is to the birds’ advantage, the researchers say, to fly in alignment because it allows them to maneuver more rapidly and better elude predators. The starlings’ flight has been likened to the flow of superfluid helium, and similar physics and mathematical principles may pertain to other types of groups, such as schools of fish or clusters of moving cells.

Dinosaurs' extinction more complicated than mere asteroid impact

28 July 2014

BBC: The extinction of the dinosaurs some 66 million years ago may have been caused by more than an asteroid impact. Other contributing factors, such as rising temperatures and sea levels and increased volcanic activity, may have made certain species more susceptible to extinction when the asteroid struck, according to a recent study by a group of 11 dinosaur experts from the UK, the US, and Canada. They say that although the dinosaurs showed no sign of long-term decline despite the presence of those environmental pressures, the timing of the asteroid strike made it particularly devastating. In fact, one of the experts, Steve Brusatte of Edinburgh University, says that had the asteroid hit Earth a few million years earlier or later, dinosaurs might still exist today.

Distant gas giant planets appear drier than expected

28 July 2014

Nature: In their study of three exoplanets some 60–870 light-years from Earth, researchers say the planets appear to be much drier than expected. They belong to a group of planets called “hot Jupiters,” which typically form in water-rich areas of solar systems. But based on Hubble Space Telescope observations of the atmospheres of exoplanets HD 189733b, HD 209458b and WASP-12b, the researchers say all three are drier than Jupiter itself. Information about the exoplanets’ atmospheres was gleaned from observations of the spectrum of IR light created as each planet crossed in front of its sun. Other researchers disagree with the findings, however. They say high-altitude clouds could have affected the results by obscuring the view. The issue may not be resolved until higher-resolution data are available from the James Webb Space Telescope or other next-generation equipment.

New aircraft is cross between airplane and helicopter

25 July 2014

Daily Mail: A new type of flying vehicle has been developed by Elytron Aircraft. The new craft combines the vertical take-off and landing capabilities of a helicopter with the speed and efficiency of a fixed-wing airplane. The design features three sets of wings: one pair of rotary wings, called “proprotors,” positioned between two pairs of fixed wings—one forward and one aft—joined with winglets. The new aircraft is more fuel-efficient and has greater range than rotary-wing craft but can take off and land without a long runway. Hence, the company says, it could be used in various capacities, including “emergency medical services, search and rescue, air taxi, and oil exploration.” A two-seater demonstration model will be on display next week at EAA Airventure Oshkosh.

Perishable food spawns development of innovative plastics

25 July 2014

NPR: Plastic food packaging involves more science and innovation than one might think. Lighter than glass, more durable than paper, and relatively cheap to produce, the plastic used in the food industry is actually an amalgam of several different types. Take a bag of potato chips: The bag may have as many as three layers—an exterior layer of polypropylene, which serves as a moisture barrier; an inner layer of thin aluminum coating, which strengthens the bag; and a layer of another plastic called polyethylene sandwiched in between. Besides the potato chips, the bags may also get a shot of nitrogen gas before they are sealed, which helps prevent the chips from getting crushed. The type of packaging used depends on the type of food inside, since some materials can cause chemical reactions and affect the product's flavor. Because all the nifty packaging creates a lot of extra waste, however, researchers are now working to create new plastics that are also environmentally friendly.

The Federal Bureau of Physics

25 July 2014
Twisting the laws of physics is often the main ingredient in science fiction. Can such twisting profitably serve other ends?

Film animation taps into scientific expertise

25 July 2014

Los Angeles Times: Physicists, engineers, and other scientists are discovering an alternative to the more traditional career paths in aerospace and academia: the movie industry. One physicist who has made the switch is Ron Henderson, a former Caltech faculty member who specializes in fluid dynamics. Henderson now works for DreamWorks Studios, where he devises complex algorithms to simulate natural phenomena, such as water and fire, for animated films. He has even won an award from the Academy of Motion Picture Arts and Sciences for his development of a fluid-simulation system called Flux. He says that besides the potential to make more money, the film business offers the challenge of finding solutions to technical problems and the opportunity to work as part of a team with people from many different backgrounds. One of Henderson’s most recent projects was to create computer-animated simulations of bubble-like spheres for tiny aliens to live in for a short, animated film titled Home.

Early-stage technologies attract corporate interest

24 July 2014
An annual networking conference pairs inventors and technology-transfer officers with companies seeking innovative ideas.

NASA calls for instrument designs for Europa mission

24 July 2014

Science: NASA has invited submissions for instrument designs to be included on the proposed Clipper mission to Europa. The agency will choose 15 to 20 of the submissions, each of which will receive $1.25 million for further development. Of those, eight finalists will be chosen for inclusion in the final satellite construction. NASA is targeting a launch in the mid 2020s. Whether the project receives funding from Congress is still an open question. NASA estimates that Clipper will require $2 billion to $3 billion.

Fracking technology helps geothermal industry grow

24 July 2014

New York Times: In 2011, less than 1% of the world's total electricity came from geothermal plants. In 2013, geothermal energy production grew to nearly 5% and is poised to grow further, especially in Indonesia, Africa, and parts of Central and South America. Currently the largest producer of geothermal energy is the US, followed by the Philippines, Indonesia, and Mexico. The growth of geothermal energy has been slow because of high upfront costs and the difficulty in identifying where to drill. Whereas most of a plant's cost (50–60%) is incurred in drilling the wells, about 10–30% of the test wells are not usable. The recent growth of the industry has been aided by the spread of hydraulic fracturing. The development of fracking as a viable method for oil and gas extraction has advanced drilling technology that can also be applied to geothermal wells.

Scientists and politicians at odds over sustainable development goals

24 July 2014

SciDev.Net: The most recent version of the United Nations’ Sustainable Development Goals (SDGs) lays out 169 targets spread across 17 goals. The report is the result of 13 working group meetings over some 16 months. However, scientists say many of the scientifically quantified targets of earlier versions have been removed. Two of the targets that pertain to climate change—zero biodiversity loss and a two-degree Celsius limit for temperature rise—and that appeared in earlier versions are essential, according to Johan Rockström, executive director of the Stockholm Resilience Centre in Sweden. “What politicians need to recognise is that if you lock yourself to these two targets, the methods to achieve these force you to address most other environmental challenges,” he said. Among those who disagree is Guido Schmidt-Traub, executive director of the UN initiative Sustainable Development Solutions Network. He says that although such targets should be considered, the most important thing is to trim the overall document down to a manageable list of goals and targets. The report is scheduled to be reviewed by the UN General Assembly in September.

Ship strikes deplete blue whale population

24 July 2014

Science: Blue whales—the largest animals known to have existed on Earth ever—were hunted almost to extinction in the 20th century. Although a 1966 ban on whaling helped many whale species rebound, the number of blue whales has not increased as much as expected. According to a study published this week in the journal PLOS One, a contributing factor may be collisions with ships. The researchers tagged and tracked blue whales off the coast of California. They found that a significant number of them were being struck and killed by ships traveling between the busy ports of San Francisco and Los Angeles. As a result, the National Oceanic and Atmospheric Administration will be reviewing the situation to find a solution, which could include speed restrictions on vessels or alterations to the commercial shipping lanes, especially during the summer at the height of the whales’ feeding season.

A battery mystery solved

24 July 2014
Experiments with x-ray diffraction explain why an important cathode material works as well as it does.

Antarctic sea ice expanding despite global warming

23 July 2014

Science: The observation that Antarctic sea ice appears to be expanding seems to run counter to the fact that Earth’s climate is growing warmer. To find out why, Ian Eisenman of the Scripps Institution of Oceanography in San Diego, California, and colleagues decided to look more closely at the data behind the 2007 and 2013 reports from the Intergovernmental Panel on Climate Change. In comparing them, the researchers found that the data had been recalibrated several times to ensure continuity from one satellite to the next over time and that discrepancies existed between the two different versions of the algorithm used to process the data. While it does indeed appear that Antarctic sea ice is expanding overall, the expansion varies regionally and seasonally, and in some places the ice is actually retreating. It is that complex spatial pattern that researchers seek to understand, and more thorough satellite data calibration methods may be needed to do so.

Henry Hartsfield Jr.

23 July 2014