Science: Prehistoric peoples may have had a sophisticated understanding of acoustics, according to researchers who presented their findings today at the annual meeting of the American Association for the Advancement of Science. Miriam Kolar of Stanford University has been studying Chavín de Huántar, an ancient village in a high valley in the Peruvian Andes. The complex consists of an elaborate maze of terraces, squares, megaliths, and tunnels. According to Kolar, the site’s interior complex of passageways served as sound-wave guides. During religious ceremonies, priests would try to evoke the mystical, supernatural voices of the oracles by blowing through conch-shell trumpets, which emitted haunting sounds that would travel through the corridors. Other meeting presenters from the emerging field of archaeoacoustics included Steven Waller, an independent scholar from La Mesa, California, whose studies have centered on Stonehenge and other stone circles in the UK; and David Lubman, from the Acoustical Society of America and the Institute of Noise Control Engineering, who has been researching the acoustical properties of Chichen Itza, Mexico.
Author Archives: Physics Today
Leaked documents give inside look at Heartland Institute
The Guardian: Confidential documents leaked from the Heartland Institute, a libertarian think tank, reveal details of the organization’s strategy on climate change, says the Guardian‘s Suzanne Goldenberg. Heartland has been a significant promoter of climate change skepticism, and the leaked documents indicate that discrediting climate science is a core mission of the organization. One plan includes spending $100 000 for spreading the message in K–12 schools that “the topic of climate change is controversial and uncertain—two key points that are effective at dissuading teachers from teaching science,” the documents said.
Although the oil industry is not one of Heartland’s big funders, the institute has received support from the Charles G. Koch Foundation, says Goldenberg; and an anonymous donor has paid millions of dollars to the institute over the last five years. Heartland has characterized the release of the documents as both theft and fraud, but it has identified only one of the documents as false.
Swiss seek funding to build satellite to clean up space junk
Science: The amount of space junk orbiting Earth is increasing. Ranging in size from an entire defunct satellite to pieces of debris less than 10 centimeters across, the junk poses a risk to astronauts and functional satellites. Due to their velocity, even the smaller objects can seriously damage anything they bump into. Researchers at the Swiss Space Center at the École Polytechnique Fédérale de Lausanne have been working on the technology for a spacecraft that will snag larger pieces of space junk and take them into Earth’s atmosphere to burn up. They’re now seeking $11 million to fund the building and launching of the craft, which could be ready between 2015 and 2017. A guidance and control system used in conjunction with cameras and ion microthrusters would allow the satellite to place itself in the correct orbit, identify the appropriate target, and get close enough to grab it—and then stabilize itself and its quarry before guiding itself toward Earth’s atmosphere. The craft’s potential first target would be Switzerland’s first space mission, a picosatellite called SwissCube that was launched in 2009.
European satellite to test Einstein’s gravitational theory
National Geographic: On Monday the European Space Agency launched a low-cost space probe into Earth orbit. LARES (Laser Relativity Satellite) is designed to measure frame dragging, or the distortion of spacetime caused by the rotation of a massive object, such as Earth. The probe, a solid metal sphere 35.5 cm wide and weighing 362 kg, is covered with reflectors. As the craft orbits the planet, an international network of laser-ranging stations will track its position. According to Einstein’s general theory of relativity, LARES‘s orbital plane should slowly precess over time. Although the shift will be small, measuring only about a few tens of millionths of a degree, the displacement should be about 4 m, enough for the laser-ranging system to record. At a cost of just $10 million, LARES may achieve greater accuracy measuring Earth’s frame dragging than did NASA’s Gravity Probe B, which cost $800 million.
Researchers find flaw in public key encryption
New York Times: Arjen K. Lenstra of École Polytechnique Fédérale de Lausanne, Switzerland, James P. Hughes of California, and their colleages have discovered a weakness in the public-key cryptography algorithm used worldwide for online shopping, banking, and other secure internet services. The algorithm uses the product of two large prime numbers, along with another number, to generate a public “key”; to encrypt data, a second person uses a formula that contains the public number. For this to be secure, the original two prime numbers must be randomly generated. Lenstra and his team analyzed several databases of public keys using the Euclidean algorithm to find the greatest common divisor of two integers. They found that in two out of every one thousand public keys, the numbers weren’t truly random. Lenstra’s team wasn’t able to discover why the random number generators failed in those cases, and they noted that the problem appears in the work of more than one software developer.
What would a nuclear blast do to your home town?
Daily Mail: The cold war is over, and the possibility of nuclear Armageddon is no longer the potent threat it once was. However, the approximately 23 000 nuclear warheads still in existence are a potential danger, albeit a less immediately compelling one. For those curious about what the consequences of a nuclear strike could be, Alex Wellerstein of the American Institute of Physics has created a Google Maps mashup that allows users to drop a virtual nuclear bomb on any destination in the world and then see the areas affected by fireball, nuclear radiation, air blast, and thermal radiation. Wellerstein developed the application to help his students understand the actual implications of nuclear warfare.
Sea urchin spine structure inspires idea for concrete
BBC: X-ray studies conducted by Jong Seto of the University of Konstanz and colleagues have identified the structural origin of sea urchin spines’ strength. The spines are made up of two forms of calcium carbonate: 92% is in calcite crystals, and the remaining 8% is in a form that lacks any crystal structure. The amorphous calcium carbonate binds the crystals together the way mortar binds bricks. The team examined sea urchin samples with a series of increasingly powerful imaging techniques. They’re now working with international companies and using the sea urchins’ spines as a model to develop a stronger, more fracture-resistant type of concrete.
Iran announces first domestically made nuclear fuel
BBC: For the first time, Iran has used nuclear fuel made in one of its own uranium enrichment facilities. The country began working toward nuclear self-sufficiency two years ago, after the collapse of a deal to procure reactor fuel from abroad. The facility at Natanz houses newer enrichment centrifuges that are three times as efficient as their predecessors; the International Atomic Energy Agency (IAEA) confirmed in January that Iran had begun producing uranium enriched up to 20% at its Qom plant. The US and EU have imposed new sanctions targeting Iranian oil sales in order to increase international pressure on Tehran over its nuclear program, which is widely believed to include the goal of making weapons. According to James Reynolds, Iran correspondent for the BBC, part of Iran’s intention in producing its own fuel is to demonstrate that international sanctions won’t make any difference.
Russian team reaches isolated Antarctic lake
Nature: Lake Vostok, the largest of more than 140 subglacial lakes buried under the surface of Antarctica, has been breached by the Russian Antarctic research program. The almost 3800 meters of ice overlying the lake give a continuous paleoclimatic record of the past 400 000 years. The Vostok drilling project was initially begun in the 1990s and used ice cores to examine ancient climatic conditions. The Russian team has taken some samples, but they are most likely from a pocket of water just above the lake; previous samples taken from ice on the bottom of the glacier, made from frozen lake water, contained cells, but it’s not known whether those samples were contaminated. The team won’t be able to extract frozen samples from the lake until December of this year, and in 2013–14, the scientists will take unfrozen water samples using numerous probes that will measure temperature, acidity, and organic compounds in the water; the probes will be packaged to prevent sample contamination.
Black hole may be devouring asteroids
National Geographic: Sagittarius A*, the supermassive black hole at the center of our galaxy, produces bright x-ray and IR flares that are as much as a hundred times brighter than the black hole’s more typical output of radiation. Kastytis Zubovas of the University of Leicester in the UK and colleagues have examined data from NASA’s Chandra X-ray Observatory and believe the flares are a result of asteroids being drawn into the black hole’s accretion disk. After the asteroids get torn apart, their remains vaporize in the accretion disk’s hot gases and produce the brilliant flares. Zubovas and his team think that asteroids need to be at least six miles wide to create flares bright enough to be observed from Earth.