Physics Today News Picks

The Chengdu Earthquake

Tue, 13 May 2008 14:09:44 -0500

Physics Today: The magnitude-7.9 earthquake that struck near Chengdu city yesterday has caused thousands to lose their lives and made millions homeless. It is the largest earthquake to hit China since 1976. According to the US Geological Survey the quake occurred as the result of motion on a northeast striking reverse fault or thrust fault on the northwestern margin of the Sichuan Basin. The earthquake's epicenter and focal-mechanism are consistent with it having occurred as the result of movement on the Longmenshan fault or a tectonically related fault. The earthquake reflects tectonic stresses resulting from the convergence of crustal material slowly moving from the high Tibetan Plateau, to the west, against strong crust underlying the Sichuan Basin and southeastern China (see maps below). "Earthquakes in this part of China are infrequent but no unexpected" says Harley Benz, Scientist-in-Charge with the National Earthquake Information Center with the USGS.

The city of Chengdu has a population of 2 million, with another 9 million in the surrounding urban area, is about 90 km southeast of the epicenter. Many western companies such as IBM, Symantec, Microsoft, Intel, Fujitsu, NEC, Motorola, and Nokia have factories and offices in the region due to Chengdu's High-Tech Industrial Development Zone. None of these companies are reporting major damage to their staff or facilities. The sina web site has photos of the damage done in the city and surrounding towns.

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On a continental scale, the seismicity of central and eastern Asia is a result of northward convergence of the India plate against the Eurasia plate with a velocity of about 50 mm/y. The convergence of the two plates is broadly accommodated by the uplift of the Asian highlands and by the motion of crustal material to the east away from the uplifted Tibetan Plateau.

"For this earthquake, because of its size, we should expect to see lots of aftershocks," says Benz. "In the first few hours following the magnitude 7.8, we recorded more than 13 earthquakes, the largest being a magnitude 6. The earthquakes are being located along a northeast trending fault, and they extend over a region about 100 kilometers or 60 miles, which is consistent with the size of this earthquake."

"In terms of the total number of aftershocks, aftershocks form an earthquake, typically this size, will be occurring weeks and months from now, but typically with time, the number of earthquakes will go down, and the size of the earthquakes will go down, but there are chances of having other large, damaging earthquakes as part of this sequence occurring in the new few days and weeks."

Microsoft joins google at star gazing

Tue, 13 May 2008 14:05:43 -0500

SFGate.com: Micosoft has launch a competitor to google sky, the popular software program that lets computer users fly through the universe, viewing stars, planets and celestial bodies. The new product is called Worldwide Telescope.

The virtual service combines images and databases from every major telescope and astronomical organization in the world.

Microsoft says it is providing the resource for free in memory of Jim Gray, the Microsoft researcher who disappeared last year while sailing his boat to the Farallon Islands on a trip to scatter his mother's ashes. The project is an extension of Gray's work.

"I never imagined (the telescope) would be so beautiful," said Alexander Szalay, an astronomy professor at Johns Hopkins University who worked with Gray on astronomy projects for more than a decade.

Gray was an expert in databases, and he came to be accepted as "a card-carrying member" of the astronomical community for his work in bringing astronomical data online, Szalay said.

A special version of the product is being developed for astronomers, and it's being considered as one way to visualize data in the Virtual Observatory, a project by the National Science Foundation to integrate all astronomical data online.

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US declares MIT science grad students are security threats

Tue, 13 May 2008 11:13:56 -0500

The Tech: Eight MIT graduate students with student visas were denied a key credential by the Department of Homeland Security. After their department appealed the decisions on their behalf, the DHS declared at least two of the students “security threats.”

The troubles stem from a new homeland security program called the Transportation Worker Identification Credential, a plastic card which, like an MIT ID, contains personally identifying information and can be read wirelessly. Without the credential, the students will soon have a harder time boarding and leaving ships at U.S. ports, including the three research ships at the Woods Hole Oceanographic Institute, where the students work.

The situation was well-known to WHOI, but it only came to MIT’s attention yesterday, when a German student forwarded to colleagues in the Earth, Atmosphere, and Planetary Sciences Department a letter from the Department of Homeland Security. The letter said in part: “I have personally reviewed the Initial Determination of Threat Assessment, your reply, accompanying information, and all other information and materials available to the TSA. Based upon this review, I have determined that you pose a security threat and you do not meet the eligibility requirements to hold a Transportation Worker Identification Credential (TWIC).” A British graduate student received a similar letter, said James A. Yoder, dean of WHOI.

Artificial atomic nuclei

Tue, 13 May 2008 09:54:13 -0500

Science: The rise of nanotechnology is garnering much attention for its ability to construct objects with individual atoms and molecules, at a scale roughly a billion times smaller than the objects we encounter in our everyday lives. In parallel to nanotechnology's often astonishing achievements, scientists have started to build a capacity to do useful work on an even more minute scale. During the past decade, chemists and physicists have begun a fabrication process at the scale of the atomic nuclei. It is an emergent means of producing, in sufficient quantities, "designer" atomic nuclei, which are new, rare isotopes with unusual numbers of neutrons or protons, or unusual decay modes (1). There are several reasons why a latent demand exists within the scientific community for new isotopes. One is that the properties of particular isotopes often hold the key to understanding some aspect of nuclear science. Another is that the rate of certain nuclear reactions involving rare isotopes can be important for modeling astronomical objects. Finally, the pursuit of ever more exotic isotopes sometimes advances basic understanding of the nuclear landscape, along with unexpected areas of application.

Iron 'snow' may explain Mercury's magnetic field

Tue, 13 May 2008 09:45:26 -0500

New Scientist: Flakes of iron snow could be falling inside the planet Mercury, according to a new experiment. This hot metal snowfall might help generate Mercury's puzzling magnetic field.

Researchers in the US have attempted to recreate the likely conditions within Mercury's liquid outer core, which is thought to be a mixture of iron and sulphur.

They used an arrangement of magnesium-oxide blocks, called a multi-anvil cell, to squeeze their iron and sulphur mixture to immense pressures, at temperatures above 2000 °Celsius. Iron crystals formed in the mixture.

"We saw iron crystals gathered at the bottom of the sample, while the liquid phase stayed on top," says team member Jie Li of the University of Illinois in Urbana-Champaign. Mercury's iron snow should form simple cubic crystals, rather than the intricate hexagonal patterns of water-ice snowflakes on Earth.
Related article Non-ideal liquidus curve in the Fe-S system and Mercury's snowing core, Geo. Rev. Lett 35, L077201

Music of the stratospheres

Tue, 13 May 2008 09:45:07 -0500

Nature: Fifteen-year oscillations in Saturn's equatorial stratosphere bear a striking resemblance to the shorter-term oscillations seen on Earth and Jupiter — akin to notes played on a cello, a violin and a viola.

Proliferation fears grow as more countries try to join the nuclear power club

Tue, 13 May 2008 09:44:56 -0500

Washington Post: At least 40 developing countries from the Persian Gulf region to Latin America have recently approached U.N. officials here to signal interest in starting nuclear power programs, a trend that concerned proliferation experts say could provide the building blocks of nuclear arsenals in some of those nations.

At least half a dozen countries have also said in the past four years that they are specifically planning to conduct enrichment or reprocessing of nuclear fuel, a prospect that could dramatically expand the global supply of plutonium and enriched uranium, according to U.S. and international nuclear officials and arms-control experts.

Much of the new interest is driven by economic considerations, particularly the soaring cost of fossil fuels. But for some Middle Eastern states with ready access to huge stocks of oil or natural gas, such as Kuwait, Saudi Arabia and the United Arab Emirates, the investment in nuclear power appears to be linked partly to concerns about a future regional arms race stoked in part by Iran's alleged interest in such an arsenal, the officials said.

Scientists get training to run for public office

Mon, 12 May 2008 15:59:39 -0500

newsobserver.com: Daniel Suson has a doctorate in astrophysics and has worked on the superconducting super collider and a coming NASA probe. Now he's heading back to school to take on an even trickier task -- getting elected to public office.

He is among a growing number of scientists who feel slighted and abused in the public debate in recent years and are mobilizing to inject "evidence-based decision making" into public policy.

Today, Suson, dean of engineering, mathematics and science at Purdue University Calumet, will join more than 70 other scientists, engineers and students at a hotel at Georgetown University for a crash course on elective politics.

Opinion: Do we understand the threat of global warming?

Mon, 12 May 2008 10:17:02 -0500

London Review of Books: John Lanchester, a contributing editor at the London Review of Books reviews a series a books on global warming and ends his review with the following paragraphs:

The remarkable thing is that most of the things we need to do to prevent climate change are clear in their outline, even though one can argue over details. We need to insulate our houses, on a massive scale; find an effective form of taxing the output of carbon (rather than just giving tradeable credits to the largest polluters, which is what the EU did – a policy that amounted to a 30 billion euro grant to the continent’s biggest polluters); spend a fortune on both building and researching renewable energy and DC power; spend another fortune on nuclear power; double or treble our spending on public transport; do everything possible to curb the growth of air travel; and investigate what we need to do to defend ourselves if the sea rises, or if food imports collapse. If we do that we may find that we develop the technologies that China and India will need. If we can show that it is possible to cut carbon output dramatically without trashing our economy – well, that might be the single most important thing we could do, far outweighing the actual impact of our emission reductions.

We know all this, but whether any of it will actually happen is a different question. It is easy for politicians to stick wind turbines on their houses and ride bicycles, but effective action on climate change is about to require doing things that are not popular. In his eponymous report, Nicholas Stern has argued that it would cost about 1 per cent of global GDP now to prevent a loss of 5 per cent of global GDP in the future. The calculation is tweaked to make the cost now sound manageably small – but it is not yet clear whether Western electorates are willing to pay it. One per cent of global GDP is 600 billion dollars, most of which would be paid by the developed world. The idea is that by paying it now we would be keeping the world’s economy on track so that by 2050 the developed world would be 200 per cent richer and the developing world 400 per cent, while our emissions decline by 60 to 90 per cent and theirs increase by 25 to 50. (One problem is that 17 per cent of that growth in developing world emissions has already been used up.) The promised economic growth is jam tomorrow; we would be paying for it today, in the form of increased taxes and lost jobs. These things are all real to voters in ways that climate change perhaps is not. Are people going to give things up in the present in order to prevent things that computer models tell them are going to happen in 25 years’ time? If they – we – aren’t, then we’re heading for breeding pairs, and camels in the Arctic.

A smattering of missing matter

Mon, 12 May 2008 10:15:36 -0500

ScienceNOW: The heavens may be strewn with stars, galaxies, and nebulae, but the fact is astronomers don't know precisely where most of the ordinary matter in the universe is hiding. A new x-ray observation could help untangle that mystery: Astronomers have located a filament of hot gas stretching all the way from one cluster of galaxies to another. The filament is thought to be one thread in a vast web containing the missing ordinary matter, and, if confirmed, it could give scientists a better idea of where the rest of the stuff is lurking.

The music math

Mon, 12 May 2008 10:15:27 -0500

Nature: At the heart of any scientific explanation of music is an understanding of how and why it affects us. In the first of a nine-part essay series, Philip Ball explores just how far we can hope to achieve a full scientific theory of music

Nasa set to join petaflop elite

Mon, 12 May 2008 10:15:17 -0500

BBC News: Nasa is making a bid to join the elite group using supercomputers whose power is measured in petaflops.

By 2009 the US space agency aims to be running a petaflop supercomputer that will be able to do 1,000 trillion calculations per second.

By 2012 it hopes to have boosted the power of this machine to 10 petaflops, to help with modelling and simulation. The new supercomputer will be at the Ames research center at Moffet Field, California.

The science behind the sitcom The Big Bang Theory

Fri, 09 May 2008 11:56:06 -0500

Science: Last October, the American TV network CBS premiered the now popular sitcom, The Big Bang Theory. Centering on two male physics postdocs and the blonde girl who moves in next door, The Big Bang Theory follows the sitcom formula of placing quirky, exaggerated characters in situations both odd and mundane.

The Big Bang Theory is the first time a prime-time comedy has taken science this seriously--partly in thanks to experimental particle physicist David Saltzberg of the University of California, Los Angeles (UCLA). Freelancer Karen Heyman recently spoke with Saltzberg and one of the show's creators Bill Prady for Science magazine, and paid a visit to the set of The Big Bang Theory, to learn how cutting-edge research gets injected into the show.

At MIT, low-tech inventions with a high impact

Fri, 09 May 2008 11:46:30 -0500

Christian Science Monitor: Unlike most of MIT, Amy Smith's workshop is far from cutting-edge. There are no next-gen computers, no vials of polysyllabic chemicals, no fancy equipment. The space is decidedly low-tech – and that's the point. D-Lab students pinpoint practical problems in the developing countries and then brainstorm and build solutions. Because the people they are trying to help are below the poverty line, the class's inventions must be simple, effective, and most important, inexpensive.

"What people need is usually completely different from what we imagine sitting here in America," says Jodie Wu, a mechanical engineering junior, whose group went on a school-sponsored trip to Tanzania over winter break.

The D in D-Lab stands for three things – development, design, and dissemination – and each is the theme of a different semester-long class.

Sahara dried out slowly, not abruptly: study

Fri, 09 May 2008 10:38:48 -0500

ENN: The once-green Sahara turned to desert over thousands of years rather than in an abrupt shift as previously believed, according to a study on Thursday that may help understanding of future climate changes.

And there are now signs of a tiny shift back towards greener conditions in parts of the Sahara, apparently because of global warming, said the lead author of the report about the desert's history published in the journal Science.
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Sahara gradually dried up over 6000 years NPR