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Keyword: physics

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  • Serious blow to dark matter theories? New study finds mysterious lack of dark matter...

    04/18/2012 12:11:06 PM PDT · by Red Badger · 58 replies ^ | 04-18-2012 | Provided by ESO
    Full title: Serious blow to dark matter theories? New study finds mysterious lack of dark matter in Sun's neighborhood The most accurate study so far of the motions of stars in the Milky Way has found no evidence for dark matter in a large volume around the Sun. According to widely accepted theories, the solar neighbourhood was expected to be filled with dark matter, a mysterious invisible substance that can only be detected indirectly by the gravitational force it exerts. But a new study by a team of astronomers in Chile has found that these theories just do not fit...
  • Mysterious Particle Found After Decades of Searching (Majorana fermion)

    04/17/2012 12:16:44 PM PDT · by presidio9 · 16 replies
    Live Science ^ | April 17, 2012 | Jesse Emspak
    An elusive particle that is its own antiparticle may have been found, and, if confirmed, would be the first time a phenomenon predicted decades ago has been seen in a real system. Some researchers suggest that in the future, this mysterious particle called a Majorana fermion could be useful in carrying bits of information in quantum computers. In a paper published in the journal Science Thursday, Vincent Mourikand Leo P. Kouwenhoven said they were able to make the Majorana fermions appear by exposing a small circuit to a magnetic field. Until now, the only suggestion of the particle's existence was...
  • Nanomachines could benefit from superlubricity

    04/11/2012 11:16:01 PM PDT · by neverdem · 5 replies
    Physics World ^ | Apr 5, 2012 | Jon Cartwright
    Researchers in China and Australia have observed superlubricity – the dropping of friction to near zero – on length scales much larger than before. They say that the phenomenon, which they measured in sheared pieces of graphite, could find applications in sensitive microscopic resonators or nanoscale gyroscopes. Superlubricity is sometimes used to mean simply very low friction, but the original meaning is that the friction between two surfaces disappears almost completely. Proposed in the early 1990s by Motohisa Hirano, then at the Nippon Telegraph and Telephone Corporation in Tokyo, Japan, and others, it relies on a special arrangement of atoms...
  • Plasma Flashlight Zaps Bacteria

    04/07/2012 11:17:23 PM PDT · by neverdem · 19 replies
    ScienceNOW ^ | 4 April 2012 | Jon Cartwright
    Enlarge Image Light therapy . A portable plasma flashlight can kill bacteria in minutes. (Credit: X. Pei et al., Journal of Physics D: Applied Physics) Credit: X. Pei et al., Journal of Physics D: Applied Physics (2012) Killing harmful bacteria in hospitals is difficult; out in the field, it can be an even bigger problem. Now, researchers may have a means for remote disinfection in a portable "flashlight" that shines a ray of cold plasma to kill bacteria in minutes. Medical scientists have high hopes for plasmas. Produced in electrical discharges, these gases of free electrons and ions have...
  • A star explodes and turns inside out

    04/04/2012 10:34:51 PM PDT · by U-238 · 10 replies
    Astronomy Magazine ^ | 3/4/2012 | Chandra X-ray Center
    A new X-ray study of the remains of an exploded star indicates that the supernova that disrupted the massive star may have turned it inside out in the process. Using long observations of Cassiopeia A (Cas A), a team of scientists has mapped the distribution elements in the supernova remnant in unprecedented detail. This information shows where the different layers of the pre-supernova star are located 300 years after the explosion, and provides insight into the nature of the supernova. The artist’s illustration shows a simplified picture of the inner layers of the star that formed Cas A just before...
  • How black holes grow

    04/03/2012 11:31:22 PM PDT · by U-238 · 19 replies
    Astronomy Magazine ^ | 3/3/2012 | University of Utah, Salt Lake City
    A study led by a University of Utah astrophysicist found a new explanation for the growth of supermassive black holes in the center of most galaxies: They repeatedly capture and swallow single stars from pairs of stars that wander too close. Using new calculations and previous observations of our Milky Way and other galaxies, “We found black holes grow enormously as a result of sucking in captured binary star partners,” said Ben Bromley from the University of Utah in Salt Lake City. “I believe this has got to be the dominant method for growing supermassive black holes,” he said. “There...
  • New data support Einstein on accelerating universe

    04/03/2012 1:00:38 AM PDT · by U-238 · 59 replies
    Science News ^ | 2/2/2012 | Elizabeth Quill
    Einstein is still the boss, say researchers with the BOSS project for measuring key properties of the universe. BOSS, for Baryon Oscillation Spectroscopic Survey, has measured the distance to faraway galaxies more precisely than ever before, mapping the universe as it existed roughly 6 billion years ago, when it was only 63 percent of its current size. The findings suggest that the mysterious “dark energy” causing the universe to expand at an accelerating rate was foreseen by Einstein, the researchers reported April 1 at the American Physical Society meeting. To keep the universe in a static state, Einstein added a...
  • Scientists Manipulate Electrons Into Material Never Seen on Earth

    03/29/2012 9:51:24 PM PDT · by neverdem · 10 replies ^ | Mar 14, 2012 | Kristen Philipkoski
    Stanford scientists have created designer electrons that behave as if they were exposed to a magnetic field of 60 Tesla—a force 30 percent stronger than anything ever sustained on Earth. The work could lead to a revolution in the materials that make everything from video displays to airplanes to mobile phones. "The behavior of electrons in materials is at the heart of essentially all of today's technologies," said Hari Manoharan, associate professor of physics at Stanford and a member of SLAC's Stanford Institute for Materials and Energy Sciences, who led the research. "We're now able to tune the fundamental properties...
  • Physicists find patterns in new state of matter

    03/29/2012 4:45:02 PM PDT · by U-238 · 20 replies ^ | 3/29/2012 |
    In a paper published in the March 29 issue of the journal Nature, the scientists describe the emergence of “spontaneous coherence,” “spin textures” and “phase singularities” when excitons—the bound pairs of electrons and holes that determine the optical properties of semiconductors and enable them to function as novel optoelectronic devices—are cooled to near absolute zero. This cooling leads to the spontaneous production of a new coherent state of matter which the physicists were finally able to measure in great detail in their basement laboratory at UC San Diego at a temperature of only one-tenth of a degree above absolute zero....
  • Pulsars: The universe's gift to physics

    03/28/2012 8:26:40 PM PDT · by U-238 · 13 replies
    Astronomy Magazine ^ | 2/20/2012 | NRAO
    Pulsars, superdense neutron stars, are perhaps the most extraordinary physics laboratories in the universe. Research on these extreme and exotic objects already has produced two Nobel Prizes. Pulsar researchers now are poised to learn otherwise-unavailable details of nuclear physics to test general relativity in conditions of extremely strong gravity, and to directly detect gravitational waves with a “telescope” nearly the size of our galaxy. Neutron stars are the remnants of massive stars that exploded as supernovae. They pack more than the mass of the Sun into a sphere no larger than a medium-sized city, making them the densest objects in...
  • New device invisible to magnetic fields

    03/24/2012 11:19:51 PM PDT · by U-238 · 26 replies · 1+ views
    Defense Talk ^ | 3/24/2012 | Defense Talk
    European researchers said Thursday they have created a device invisible to a static magnetic field that could have practical military and medical applications. Fedor Gomory and colleagues in Slovakia and Spain designed a cloak for a direct current, or dc, magnetic field that is static and produced by a permanent magnet or coil carrying a direct current. DC magnetic fields are used in MRI imaging devices, in hospitals and in security systems, such as those in airports. The researchers' device, described in a study in Friday's edition of the journal Science, features a cylinder with two concentric layers. While the...
  • Will Space Battles Be Fought with Laser Weapons?

    03/22/2012 1:34:51 AM PDT · by U-238 · 33 replies · 2+ views
    Life's Little Mysteries ^ | 3/16/2012 | Adam Hadhazy
    What would science fiction be without laser beams? From handheld ray guns to spaceship-mounted turbolasers, the futuristic weapon of choice definitely involves bright, colorful blasts of energy. In the early 21st century, projectiles still remain the standard means of inflicting damage from a distance. Yet continued research into "directed-energy" weapons by the United States military, among others, could someday bring lasers to a battlefield near you. Lasers are already used in guidance, targeting and communication applications, but significant technological obstacles stand in front of turning them into weapons by themselves. For certain niche scenarios, lasers might prove themselves ideal. It...
  • ScienceShot: Crystal Clear Nano-Gold

    03/21/2012 11:06:30 PM PDT · by neverdem · 9 replies
    ScienceNOW ^ | Robert F. Service | 21 March 2012
    Credit: Image courtesy of Nature Press Superman has nothing on Jianwei Miao, at least in the vision department. Miao, a physicist at the University of California, Los Angeles, and his colleagues have developed a way to image any type of nanoparticle with unprecedented accuracy. In the picture above, the technique, called electron tomography, shows a gold nanoparticle made up of 3871 atoms. Inside the nanoparticle, the researchers could easily resolve multiple "grains" (green, gold, blue, and red) in which atoms in each grain share a common atomic alignment that is offset from neighboring grains. The technique also manages to...
  • The Science of Rail Guns

    03/20/2012 9:44:57 PM PDT · by U-238 · 43 replies
    i09 ^ | 3/20/2012 | Keith Veronese
    Ubiquitous in science fiction, rail guns are a hot area of military research in real life too. But will we ever really get to use them the way people in science fiction do? And could rail guns be used for a non-violent reason — inexpensively launching payload into space? Halo Reach ends with your Spartan taking up a mounted rail gun to destroy an incoming Covenant ship. Rail guns are the basis for a funny aside in Mass Effect 2. They're used in Babylon 5 and Stargate Atlantis and The Last Starfighter. And they're a devastating hand-held weapon in the...
  • Recovering three-dimensional shape around a corner using ultrafast time-of-flight imaging

    03/20/2012 2:48:27 PM PDT · by Stoat · 4 replies · 2+ views
    Nature ^ | March 20, 2012 | Andreas Velten, et al
    The recovery of objects obscured by scattering is an important goal in imaging and has been approached by exploiting, for example, coherence properties, ballistic photons or penetrating wavelengths. Common methods use scattered light transmitted through an occluding material, although these fail if the occluder is opaque. Light is scattered not only by transmission through objects, but also by multiple reflection from diffuse surfaces in a scene. This reflected light contains information about the scene that becomes mixed by the diffuse reflections before reaching the image sensor. This mixing is difficult to decode using traditional cameras. Here we report the combination...
  • Retest of neutrino speed suggests Einstein was right, after all

    03/19/2012 4:22:37 PM PDT · by U-238 · 16 replies · 1+ views
    Christian Science Monitor ^ | 3/19/2012 | By Clara Moskowi
    Six months after physicists shocked the world by announcing they'd found particles seemingly traveling faster than light, the growing scientific consensus seems to be that the results were flawed. Neutrinos are the vampires of physics. Researchers at the ICARUS project in Italy have recreated an independent version of the original Switzerland-based experiment, called OPERA, and found that their particles traveled at a respectable, sub-light speed. Though the results don't automatically disprove OPERA's findings, they add to most scientists' sense that the shocking finding was an anomaly "The evidence is beginning to point towards the OPERA result being an artifact of...
  • Message Encoded in Neutrino Beam Transmitted through Solid Rock

    03/18/2012 11:29:14 PM PDT · by U-238 · 18 replies · 1+ views
    Scientific American ^ | 3/16/2012 | John Matson
    Neutrinos are having a moment. They’re speeding across Europe (just how fast is under review), they’re changing flavors in China and, now, they’re carrying rudimentary messages through bedrock in Illinois. A team of physicists encoded a short string of letters on a beam of neutrinos at Fermi National Accelerator Laboratory in Batavia, Ill., and sent the message to a detector more than a kilometer away. On the journey the neutrinos passed through 240 meters of solid rock, mostly shale. What was the word they transmitted in the preliminary demonstration? “Neutrino.” The experiment is described in a paper posted to the...
  • Hydrogen takes a new form

    03/10/2012 10:36:13 PM PST · by U-238 · 19 replies
    Science News ^ | 3/1/2012 | Alexandra Witze
    Squeezing hydrogen at extreme pressures changes it into a mix of honeycombed atoms layered with free-floating molecules — an entirely new state of the element and the first new phase found in decades. If confirmed, the discovery will be only the fourth known phase of hydrogen, the simplest element and one long probed for basic insights into the nature of matter. “I think we have pretty bulletproof evidence that there is a new phase,” says Eugene Gregoryanz of the University of Edinburgh, leader of the team that will report the work in an upcoming Physical Review Letters. Hydrogen’s first three...
  • Loose cable blamed for speedy neutrinos

    03/06/2012 1:16:25 AM PST · by U-238 · 41 replies
    Science News ^ | 2/23/2012 | Devin Powell
    Faulty wiring has been proposed as the glitch that caused a European physics experiment to clock particles flying faster than light. Scientists at Italy’s OPERA experiment reported in September that nearly weightless particles called neutrinos were apparently traveling from the CERN laboratory on the Swiss-French border to an underground detector in Italy, 730 kilometers away, faster than the speed of light. The apparent violation of Einstein’s theory of special relativity immediately produced a chorus of theorists offering reasons why neutrinos simply could not be going that fast (SN: 11/5/11, p. 10). “It was always clear to me that the results...
  • Graphyne Could Be Better Than Graphene

    03/04/2012 12:33:55 AM PST · by neverdem · 2 replies
    ScienceNOW ^ | 1 March 2012 | Jon Cartwright
    Enlarge Image The new graphene. Graphyne may be less famous than graphene, but it could have better electronic properties. Credit: D. Malko et al., Phys. Rev. Lett. (2012) Graphene, a layer of graphite just one atom thick, isn't called a wonder material for nothing. The subject of the 2010 Nobel Prize in physics, it is famed for its superlative mechanical and electronic properties. Yet new computer simulations suggest that the electronic properties of a little-known sister material of graphene—graphyne—may in some ways be better. The simulations show that graphyne's conduction electrons should travel extremely fast—as they do in graphene—but...