Physics Today Daily Edition
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Updated: 4 hours 37 min ago
In a space-based gravitational-wave detector, gravity should be the only force accelerating an interferometer.
Nature: Usually with volcanoes, the surface subsides around them because of the draining of magma-filled chambers in the ground beneath. But magma may pool in chambers far from any active volcano, according to a new study. Using satellite radar data and geodetic surveys, Ian Hamling of GNS Science in New Zealand and his colleagues were able to distinguish an unexpected rise in the ground in the Taupo Volcanic Zone of New Zealand’s North Island. Moreover, the ground appears to have been rising for more than a half century and at an ever-increasing rate—from about 5 mm/year in the 1950s to some 12 mm/year by the mid 2000s. However, the researchers say the magma increase does not necessarily mean an eruption is imminent. Moreover, similar processes have probably been going on all over the world; it is only now that instruments have been developed to detect them.
New York Times: Smart materials and technologies are enabling the construction of zero-energy homes, which generate as much energy as they consume over the course of a year. The energy efficiency comes from a renewable energy system, such as solar panels, combined with improved building materials, including spray-foam insulation, dual-pane windows, and LED lighting. Smart thermostats and remotely controlled water heaters help regulate the flow of energy. Since 2013 the US Department of Energy has certified about 700 such homes, and it estimates it will certify another 1000 this year and 3000 in 2017.
New Scientist: A new study reveals a disparity between the two leading methods for calculating the rate of expansion of the universe. Adam Riess of the Space Telescope Science Institute in Baltimore, Maryland, and his colleagues compared the two best techniques—looking at the size of the temperature fluctuations in the cosmic microwave background (CMB) and measuring the rate at which distant galaxies are receding. The receding galaxies method, which Riess pioneered in the 1990s, implies that the universe is expanding 9% faster than theoretical estimates based on CMB data suggest. The researchers say that discrepancies in the CMB data may be to blame. If so, newer equipment and measuring techniques should resolve the problem. If the models prove to be accurate, however, the discrepancy could indicate that changes need to be made to our understanding of the laws of physics; for example, dark energy may be growing denser.
NPR: Complaints regarding the new types of brooms available in the sport of curling prompted the World Curling Federation to organize a summit to test brushes and sweeping techniques. Traditionally, the game hinges on the skill of the thrower, who slides the stone down a sheet of ice toward a target called the house. To help direct it toward the house, two sweepers use brooms to sweep the ice in front of the stone. However, some of the new brooms actually scratch the ice, which gives the sweepers much more control over the stone than they have had traditionally. To formulate new rules and equipment standards to ensure that the spirit of the game is maintained, top-level athletes and curling experts gathered at the summit to test more than 50 brush constructions and various sweeping techniques.
Developments in snapshot imaging and computational processing improve resolution at unprecedented frame rates.
Scientific American: The 2017 spending bill passed last week by the US House Appropriations Committee calls for a 20% cut from last year’s spending for climate science research by the National Oceanic and Atmospheric Administration. Among the programs affected are carbon-monitoring stations from the 1950s that are in dire need of updating, a proposed facility to verify fossil fuel emissions by nations that signed last year’s Paris climate agreement, and a proposal to expand NOAA’s ocean acidification monitoring program. The bill would also impose a 12% cut from 2016 funding levels for NASA’s earth sciences division.
New York Times: On 2 June the Norwegian Academy of Science and Letters announced the recipients of this year’s Kavli Prizes. The astrophysics prize went to Ronald Drever and Kip Thorne of Caltech and Rainer Weiss of MIT for their role in the detection of gravitational waves. The nanoscience prize was shared among Gerd Binnig (formerly of IBM Zurich Research Laboratory), Christoph Gerber of the University of Basel in Switzerland, and Calvin Quate of Stanford University for the invention of atomic force microscopy. The neuroscience prize was given to Eve Marder of Brandeis University; Michael Merzenich of the University of California, San Francisco; and Carla Shatz of Stanford for their discoveries concerning the flexibility of the nervous system and the brain. The recipients of each prize split $1 million.
New Scientist: Although curved optical lenses are ubiquitous in telescopes, microscopes, and cell phone cameras, the size of those devices is limited by the thickness and weight of the glass. Now researchers have used metamaterials to create a lens that is thinner than the wavelengths of the light waves it focuses. The scientists carved tiny blocks of titanium dioxide, rotated them at different angles, and mounted them on a thin piece of glass. Each 600-nm-thick lens, which was tuned to either red, green, or violet light, achieved sharper focus than a 55-mm-thick Nikon lens, with minimal loss of light. Next the research team plans to expand the range of color the lenses can detect.
Economist: In the mid 1970s, physicist Stephen Hawking challenged the theory of causal determinism by proposing that information could be lost forever if matter were sucked into a black hole because the black hole would eventually disintegrate. Now, however, he has revised that idea and shows how the evaporation of black holes does not necessarily mean that all the information contained in the swallowed matter will be destroyed. Hawking instead proposes that when matter falls into a black hole, it leaves traces of the information it contained in the form of the number and position of two soft particles, photons and gravitons. The informational record remains even after the black hole has disappeared. Although the explanation is incomplete because it accounts for only one property of matter—its electric charge—the principle supports the established laws of physics and could lead to a more complete understanding of black holes and the universe.
Measurements of iron's thermal conductivity hint that the planet's solid center is relatively young—and not responsible for Earth's dynamo long ago.
Washington Post: As the world’s population grows and countries’ economies improve, more people are purchasing air conditioning units for their homes and businesses. According to a study published last year, as many as 1.6 billion new air conditioners could be installed by 2050. To discuss the global impact on climate those installations will have, representatives from around the world are meeting in San Francisco this week at the seventh Clean Energy Ministerial. They will consider ways to lessen the environmental impact, such as by designing air conditioners to be more energy efficient and by finding alternative coolants to hydrofluorocarbons, which contribute to global warming.
BBC: Measuring 57.1 km in length and requiring 17 years to build, the Gotthard Base Tunnel cuts through the Swiss Alps to connect northern and southern Europe. The tunnel is flatter, straighter, and deeper than a previous one built in 1980, and its purpose is to expedite the transport of both people and goods across the Alps. Some 65 passenger trains and 260 freight trains will use the tunnel daily. It is expected to help reduce the number of trucks traveling through Switzerland, which has been estimated to be as many as a million per year.
New electricity pricing policies are needed to help nuclear plants remain open and allow them to compete with cheap, abundant natural gas, officials say.
Journalists must decide: Should new research "dramatically shift the national debate over cell phone safety"?
Nature: On 6 July some 100 chipsats, or tiny cubesats, are to be sent up into orbit near the International Space Station. Each chipsat measures just 3.2 cm2 in area and weighs about 5 g. They are to be deployed en masse from a KickSat satellite and, once in place, will use a radio, an antenna, and a pair of 60 milliamp solar cells to transmit data on energy load and orientation. Once that mission is completed, the chipsats will fall out of orbit and burn up in Earth’s atmosphere. The launch is the second attempt to test the tiny devices; an earlier satellite launched in 2014 failed to deploy its cargo of chipsats before it disintegrated. Chipsat technology could prove useful for a number of scientific projects, such as determining the amount of drag created by small bits of debris in the upper atmosphere or mapping Earth’s magnetic field.
Science: After meeting with several Nobel laureates and a winner of the Fields Medal, French president François Hollande has agreed to cancel a €134 million proposed cut to the country’s research budget. The cut would have affected four major agencies: the National Center for Scientific Research, the National Institute for Agricultural Research, the National Institute for Computer Science and Applied Mathematics, and the Alternative Energies and Atomic Energy Commission. However, €122 million will still be trimmed from the budget, which will mostly affect higher education. Hollande also agreed to work toward increasing the funds available for research and higher education in the next annual budget.
NPR: Detailed seasonal forecasts are critical for farmers in Rwanda, a hilly country where the weather varies by altitude. However, Rwanda's weather-tracking system was completely destroyed during the bloody civil war and genocide that erupted in 1994. The weather system had consisted of about 100 volunteers who recorded temperature and rainfall data from instruments at small outdoor observation stations. Over the 100-day conflict, many of the stations were destroyed and the volunteers who staffed them were killed. It took some 15 years to recruit new volunteers and reassemble the weather network. Then, to fill in the 15-year data gap, climate scientist Tufa Dinku of Columbia University created a substitute data record by estimating rainfall and temperature through the use of satellite imagery and computer models. The result is a weather-forecasting setup that may one day rival those of the rest of the world.
Science News: Although physical phenomena such as coin tosses and dice rolls can generate random numbers, those methods are too slow for modern applications in such areas as statistics and cryptography. For those purposes, computational algorithms can create number sequences with random properties, but the numbers are not truly random because eventually the sequence will start repeating. Now a randomness extractor has been created that combines two independent sources of random numbers and discards any data that may be correlated or biased. The result is a more resilient system, even when very weak sources are used. The extractor should prove ideal for encrypting sensitive information and foiling would-be hackers.