Month: May 2008
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Orbits ‘n’ obits
The other highlights from the physics arXiv this week: Measuring the Scalar Curvature with Clocks and Photons Microscopic Atom Optics: from Wires to an Atom Chip So You Want to be a Professional Astronomer! Nuclear Magic Numbers: New Features Far From Stability
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VoIP threatened by steganographic attack
Steganography is the art of hiding message when they are sent, in a process akin to camouflage. In cryptography, on the other hand, no attempt is made to hide the message, only to conceal its content. Today, Wojciech Mazurczyk and Krzysztof Szczypiorski of the Warsaw University of Technology in Poland explain how VoIP services are…
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How to turn a narrow slit into a large window
How do you turn a narrow slit into a large window? Fill it with a metamaterial that captures and transmits as much light as the bigger window. At least, that’s what Xiaohe Zhang and colleagues at Shanghai Jiao Tong University in China tell us. Metamaterials are substances constructed in a way that gives them exotic…
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Friction-free sliding observed in nanoparticles
On the atomic scale, friction is a curious beast and explaining exactly how it arises (and why in certain circumstances it appears to be absent) has stumped tribologists. For the growing number of engineers designing and building nanomachines, one important question is how friction scales with the contact area between nanoscale components. In the macroscopic…
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The surprisingly rich physics of peeling paper
Take a standard piece of copier paper (80 g/m^2) and carefully peel it into two sheets. Listen out for the way it tears and watch how fast the peel line creeps. What you’ll see and hear is a stick-slip phenomenon in which the creep velocity varies over many orders of magnitude, with small movements of…
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The mystery of the Plutonic color scheme
Pluto’s three satellites, Hydra, Nix and Charon, are all a similar shade of grey. In fact, Nix and Hydra have exactly the same colour to within our ability to measure it. Pluto, on the other hand, is a beautiful shade of red. How come? The current thinking is that Charon, Hydra and Nix are a…
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In case ya missed ’em…
The peaches from the arXivblog this week: The trouble with optical invisibility cloaks Why ET will phone using neutrinos not photons Can dark matter explain the flyby anomalies? Dark energy linked to supervoids and superclusters First test of exotic space thruster ends in explosion
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Millions ‘n’ perihilions
The best of the rest from the physics arXiv this week: The ANTARES Neutrino Telescope: first results Stability of Thermohaline Circulation with Respect to Fresh Water Release Universal Scaling of Forest Fire Propagation Towards Applied Theories based on Computability Logic A Model of Dissociated Cortical Tissue
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First test of exotic space thruster ends in explosion
In 2006, Mason Peck at Cornell University in Ithaca dreamt up with an entirely new way to control satellites orbiting planets that have a magnetic field. The idea is based on the Lorentz force: that a charged particle moving through a magnetic field experiences a force perpendicular to both its velocity and the field. So…
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Dark energy linked to supervoids and superclusters
“The most profound puzzle of contemporary physics” is how Benjamin Granett and colleagues from the University of Hawaii in Honolulu describe the problem of dark energy. And they’re not kidding. What we have is the extraordinary observation that type 1a supernovas in the most distant galaxies in the universe are dimmer than they ought to…