Waves & Packets
Jun. 2, 2012

Your complete go-to guide for June's transit of Venus
Sky and Telescope
On June 5 in North and Central America, and June 6 in Asia, Australia and most of Europe, the planet Venus will cross in front of the Sun. This will be only the eighth such transit of Venus since the invention of the telescope, and the last one until Dec. 10-11, 2117. People in most of Hawaii, Alaska, Australia, the western Pacific and eastern Asia will be able to see the entire transit, which will last six hours 40 minutes. Most people in North America will be able to observe the first several hours before the sun sets. Most people in Europe will see the final stages of the transit after sunrise.

Research astronomers will use a variety of ground-based and space telescopes to observe the transit to better understand Venus's thick greenhouse atmosphere, the black-drop effect and to help better understand how to use the transit method to discover and characterize planets orbiting other stars. To celebrate the transit, Sky & Telescope is offering its SkyWeek starwatching app (available for both the iPhone and Droid) free of charge from June 1-7.More

Reanalysis finds dark matter in the solar neighborhood
New Scientists
In April, there was a report of an analysis of the kinematics of 412 stars at 1-4 kiloparsecs from the Galactic midplane that lead to the conclusion that there no evidence of dark matter in the solar neighborhood. Now a reanalysis of the data by a different team finds that indeed there is dark matter in the cosmic neighborhood and the amount (0.008 +- 0.002 Msunpc-3) agrees with previous estimates. According to the new analysis, posted on arXiv and submitted to the Astrophysical Journal, the original conclusion of no dark matter was based on the erroneous assumption that the mean azimuthal velocity of the stellar tracers is independent of Galactocentric radius at all heights. The new team asserts that the correct assumption, which is supported by observational data, is that the circular speed is independent of radius in the midplane only.More

8 modern astronomy mysteries scientists still cannot explain
msnbc
To round up some of the most enduring mysteries in the field of astronomy, Science has enlisted help from science writers and members of its Board of Reviewing Editors to choose eight puzzling questions being asked by leading astronomers today. The mysteries involve dark matter and dark energy, missing baryons, supernovae, hydrogen gas reionization, cosmic rays, planet formation and solar dynamics.More

Milky Way, Andromeda galaxies set to crash — in 4 billion years
Space Telescope Science Institute
Astronomers working with the Hubble Space Telescope have determined that the Milky Way is set to collide with its closest neighbor, the Andromeda galaxy. A third galaxy, the Triangulum galaxy, may join the collision, resulting in a ternary merger of galaxies. The collision, which is predicted to be 4 billion years off, will likely fling the sun to a new region of the galaxy, and other stars will be thrown into new orbits around the galactic center. Computer simulations derived from Hubble's data show that it will take an additional 2 billion years after the encounter for the interacting galaxies to completely merge under the tug of gravity and reshape into a single elliptical galaxy similar to the kind commonly seen in the local universe. The analysis is available in a trio of papers posted on arXiv. More

ALMA turns its eyes to Centaurus A
European Southern Observatory
New images of the center of the distinctive galaxy Centaurus A, made with the Atacama Large Millimeter/submillimeter Array (ALMA), shows how the new observatory allows astronomers to see through the opaque dust lanes that obscure the galaxy’s center, with unprecedented quality. Centaurus A is a massive elliptical radio galaxy and as the most prominent nearest, radio galaxy in the sky is one of the most studied. In visible light Centaurus A shows dark band that obscures its center, which hosts hosts a supermassive black hole with a mass of about 100 million times that of the Sun. The band contains large amounts of gas, dust and young stars. To see through the obscuring dust in the central band, astronomers need to observe using longer wavelengths of light. The new ALMA images, which are overlayed onto near-infrared and optical images, are the sharpest and most sensitive such observations ever made, and they reveal the position and motion of the clouds of gas in the galaxy. ALMA is currently in its Early Science phase of observations and is still under construction, but is already the most powerful telescope of its kind. The observatory has just issued the Call for Proposals for its next cycle of observations, in which the growing telescope will have increased capabilities.More

Using laser frequency combs to hunt for exoplanets
Max-Planck-Institut für Quantenoptik
A recent report in Nature demonstrates that laser frequency combs can be used for the calibration of astronomical spectrographs, which will help astronomers find extra-solar planets. It might even become possible to use this Nobel Prize-winning technology to directly measure very small changes in the expansion velocity of the universe. Frequency combs were originally developed to study atoms in the quantum regime. But they are very useful as metrology tools because as calibrations standards they do not change over time. One important method in exoplanet searches involves looking for Doppler shifts in the spectral lines seen in the planets' parent stars. Doppler shifts in stellar spectral lines tell a story of the kinematics between the source and observing platform. In astronomy Doppler shifts are very small, and frequency comb calibrations of telescopic spectrographs provide an accurate and precise way to discern changes that hint of planetary transits, and eventually wholesale movements of entire galaxies.More

Electrons combining to Cooper pairs observed directly in cuprate superconductor
Lawrence Berkeley Laboratory
Cooper pairs, conducting pairs of electrons in superconductors, is a foundational concept in the BCS theory of superconductivity. The BCS theory has known shortcomings, even fervent detractors, and there is no theory that that satisfactorily explains superconductivity in all observed cases, certainly not satisfactorily in high-Tc ceramic superconductors. But recently, researchers at LBL have been able to directly observe the recombination of electrons to Cooper pairs in Bi2Sr2CaCu2O8+x using ultrafast angle-resolved photoemission spectroscopy. The ultrafast ARPES experiment involves kicking electrons out of Cooper pairs by either a UV or IR pulse, then using an IR probe to follow the recombination back to correlated pairs. The results, reported in Science, showed marked dependencies on both excitation density and crystal momentum.More

Symmetry points to universal mechanism for superconductivity in iron pnictides and chalcogenides
American Physical Society
Iron-based superconductors have generated great excitement since their discovery in 2008. At first glance they seem to have properties very similar to cuprates, but a deeper analysis into their band structures reveals some important differences. Satisfactory theories for iron-based superconductors have heretofore turned out to be much more complex than those for cuprates. In fact, researchers have thought that an entirely different mechanism must be responsible for superconductivity in iron-based compound. But work reported in Physical Review X reveals that simple S4 symmetry and gauge transformations resulting in isospin doublets in the microscopic analysis of iron-based superconductors yield qualitative analogies to theoretical treatments of cuprates. This new derivation provides a unified understanding of iron pnictides and iron chalcogenides, and suggests that cuprates and iron-based superconductors share an identical high-Tc superconducting mechanism.More

Science is no cure for climate denial
Treehugger Blog
A new study published in Nature Climate Change drives the point home: There's really no amount of science that's going to change the staunch climate change naysayer's mind. Scientists have been lamenting public misunderstanding of science, not only in climate science, but biomedical and social sciences for generations. The clarion call has been for greater science literacy for the general public and communication skills for scientists. This new study suggests that this is simply not going to help. In fact, it reveals that "Members of the public with the highest degrees of science literacy and technical reasoning capacity were not the most concerned about climate change. Rather, they were the ones among whom cultural polarization was greatest." People are dug into the ideological camps with their tribal members. And what's more, smart, informed people tend to be especially good at cramming new data into their pre-existing biases. Echo-chambered news, purposeful spin and class-based biases in mass media access cannot be helpful to the problem either. More

Kavli Foundation announces awards in nanoscience and astrophysics
The Kavli Foundation
The 2012 Kavli Prizes for nanoscience and astrophysics were recently announced at the World Science Festival. The Kavli Prize in Nanoscience was awarded to MIT professor Mildred Dresselhaus "for her pioneering contributions to the study of phonons, electron-phonon interactions and thermal transport in nanostructures." David Jewitt, Jane Luu and Michael Brown share the Kavli Prize in Astrophysics "for discovering and characterizing the Kuiper Belt and its largest members, work that led to a major advance in the understanding of the history of our planetary system." The Kavli Prize is a partnership between the Norwegian Academy of Science and Letters, the Kavli Foundation and the Norwegian Ministry of Education and Research. It was established to recognize outstanding scientific research, honor highly creative scientists, promote public understanding of scientists and their work, and foster international cooperation among scientists. More

National Society of Black Physicists jobs board postings
NSBP
Advanced Topics in Astrostatistics
Biophotonic Solutions 2012 MIIPS Ultrafast Pulse Shaping Workshop
Faculty Positions in Science, Technology and Innovation
Research Datacenter and Computing Infrastructure Manager
SKA Project Scientist
Women's Business Enterprise National Council Student Program
3x Senior Astronomers — SKA Africa
Nanoscale Measurements For Soft Matter Systems
NASA Postdoctoral Fellowships
National Astrophysics and Space Science Program
Postdoctoral Research Associate PositionsMore

Latest research from Superconductor Science and Technology
IOP Journal
Influencing factors on the electrical transport properties of split-melt processed Bi2Sr2CaCu2Ox round wires

Evidence that filament fracture occurs in an ITER toroidal field conductor after cyclic Lorentz force loading in SULTAN

The observation and explanation of the spontaneous nucleation behavior in SmBaCuO–Ag solution

Transport AC losses of YBCO pancake coils wound from parallel connected tapes

Magnetization measurements on ITER Nb3Sn CICC and strands subjected to irreversible strain degradationMore

Latest research from Physics of the Earth and Planetary Interiors
Elsevier
The global CMT project 2004–2010: Centroid-moment tensors for 13,017 earthquakes

Variations of magnetic properties in thin lava flow profiles: Implications for the recording of the Laschamp Excursion

Numerical models of shear-induced melt band formation with anisotropic matrix viscosity

Nonisostatic effects on crustal thickness: A study using CRUST2.0 in Fennoscandia

Accurate and efficient modeling of global seismic wave propagation for an attenuative Earth model including the centerMore