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Hall Effect at the Speed of Light: How Can You Demonstrate...

Wed, 30 May 2012 17:52:00 -0700

Hall Effect at the Speed of Light: How Can You Demonstrate Relativistic Effects With Your Mobile Phone? |

The relativistic Hall effect describing objects rotating at speeds comparable with the speed of light has now been reported.

The work by Konstantin Bliokh and Franco Nori at RIKEN in Japan, NAS in Ukraine, and the University of Michigan in the US sheds light on aspects of fundamental physics, and you can demonstrate some aspects of this with your mobile phone.

As any cameraman knows, recording a fast rotating object such as a fan using a “rolling shutter” camera, like those found on mobile phones, results in weird distortions.

See for example,http://www.youtube.com/watch?v=17PSgsRlO9Q,http://www.youtube.com/watch?v=LVwmtwZLG88&feature=fvwrel.

Less widely understood — until now — is the link between these distortions and some of the landmark theories in physics, namely Einstein’s relativity and the Hall effect.

Hall effects describe the interplay of rotation and linear motion in objects. There are already a number of manifestations of the Hall effect, including classical, quantum, and ‘spin-based’.

Relativity describes effects that arise when an object approaches the speed of light. This study considered the Hall effect as arising naturally under special relativity conditions without any external ﬁelds. The researchers found that a relativistic treatment of rotating bodies and quantum wave systems with angular momentum results in deformations and a shift in the geometric centre. The distortions have parallels with those found when recording a rotating object with a rolling shutter camera.

“Our description makes relativistic and quantum aspects of angular momentum fully consistent with each other,” conclude Bliokh and Nori. continue reading

Cloak of Invisibility: Engineers Use Plasmonics to Create an...

Wed, 30 May 2012 13:59:15 -0700

Cloak of Invisibility: Engineers Use Plasmonics to Create an Invisible Photodetector |

It may not be intuitive, but a coating of reflective metal can actually make something less visible, engineers at Stanford and UPenn have shown. They have created an invisible, light-detecting device that can “see without being seen.”

At the heart of the device are silicon nanowires covered by a thin cap of gold. By adjusting the ratio of metal to silicon — a technique the engineers refer to as tuning the geometries — they capitalize on favorable nanoscale physics in which the reflected light from the two materials cancel each other to make the device invisible.

Pengyu Fan is the lead author of a paper demonstrating the new device published online May 20th in the journal Nature Photonics. He is a doctoral candidate in materials science and engineering at Stanford University working in Professor Mark Brongersma’s group. Brongersma is senior author of the study.

Cloak of invisiblity

Light detection is well known and relatively simple. Silicon generates electrical current when illuminated and is common in solar panels and light sensors today. The Stanford device, however, is a departure in that for the first time it uses a relatively new concept known as plasmonic cloaking to render the device invisible.

The field of plasmonics studies how light interacts with metal nanostructures and induces tiny oscillating electrical currents along the surfaces of the metal and the semiconductor. These currents, in turn, produce scattered light waves.

By carefully designing their device — by tuning the geometries — the engineers have created a plasmonic cloak in which the scattered light from the metal and semiconductor cancel each other perfectly through a phenomenon known as destructive interference.

The rippling light waves in the metal and semiconductor create a separation of positive and negative charges in the materials — a dipole moment, in technical terms. The key is to create a dipole in the gold that is equal in strength but opposite in sign to the dipole in the silicon. When equally strong positive and negative dipoles meet, they cancel each other and the system becomes invisible. continue reading

Cassini Spots Tiny Moon, Begins to Tilt Orbit | NASA’s...

Wed, 30 May 2012 09:53:08 -0700

Cassini Spots Tiny Moon, Begins to Tilt Orbit |

NASA’s Cassini spacecraft made its closest approach to Saturn’s tiny moon Methone as part of a trajectory that will take it on a close flyby of another of Saturn’s moons, Titan. The Titan flyby will put the spacecraft in an orbit around Saturn that is inclined, or tilted, relative to the plane of the planet’s equator. The flyby of Methone took place on May 20 at a distance of about 1,200 miles (1,900 kilometers). It was Cassini’s closest flyby of the 2-mile-wide (3-kilometer-wide) moon. The best previous Cassini images were taken on June 8, 2005, at a distance of about 140,000 miles (225,000 kilometers), and they barely resolved this object.

Also on May 20, Cassini obtained images of Tethys, a larger Saturnian moon that is 660 miles (1,062 kilometers) across. The spacecraft flew by Tethys at a distance of about 34,000 miles (54,000 kilometers).

Cassini’s encounter with Titan, Saturn’s largest moon, on May 22, is the first of a sequence of flybys that will put the spacecraft into an inclined orbit. At closest approach, Cassini will fly within about 593 miles (955 kilometers) of the surface of the hazy Titan. The flyby will angle Cassini’s path around Saturn by about 16 degrees out of the equatorial plane, which is the same plane in which Saturn’s rings and most of its moons reside.

Cassini’s onboard thrusters don’t have the capability to place the spacecraft into orbits so inclined. But mission designers have planned trajectories that take advantage of the gravitational force exerted by Titan to boost Cassini into inclined orbits. Over the next few months, Cassini will use several flybys of Titan to change the angle of its inclination, building one on top of the other until Cassini is orbiting Saturn at around 62 degrees relative to the equatorial plane in 2013. Cassini hasn’t flown in orbits this inclined since 2008, when it orbited at an angle of 74 degrees. continue reading

Stunning View of Lyrids and Earth at Night | On the night of...

Tue, 29 May 2012 17:58:18 -0700

Stunning View of Lyrids and Earth at Night |

On the night of April 21, the 2012 Lyrid meteor shower peaked in the skies over Earth. While NASA allsky cameras were looking up at the night skies, astronaut Don Pettit aboard the International Space Station trained his camera on Earth. Video footage from that night is now revealing breathtaking images of Earth with meteors ablating — or burning up — in the atmosphere.

The downlinked image to the right shows a Lyrid meteor in a six-second exposure, taken on April 22, 2012 at 5:34:22 UT. The International Space Station position was over 88.5 W, 19.9 N at an altitude of 392 km. NASA astronomer Bill Cooke mapped the meteor to the star field — seen in this annotated image — and confirmed that the meteor originated from the Lyrid radiant.

The image is rotated so that the north celestial pole (NCP) is roughly in the up direction. The lights of Florida are clearly seen above and to the right of the meteor. Cuba, the Florida Keys and the eastern Gulf Coast shoreline are also visible. Some brilliant flashes of lightning are also prevalent in the image.

A movie of a International Space Station’s pass over Earth on the night of April 22, 2012, during the peak of the Lyrid meteor shower — a composite of 316 still frames seen during the flyby — is available at:http://www.nasa.gov/multimedia/videogallery/index.html?media_id=143997541

Days of ‘Gizmo’ Launches Return: NASA Team to Test...

Tue, 29 May 2012 13:59:01 -0700

Days of ‘Gizmo’ Launches Return: NASA Team to Test New Vehicle-Descent Technologies |

NASA technologists will get a chance next summer to relive the good old days when Agency engineers would affix space-age gizmos to rockets just to see if the contraptions worked.

In what will be the first of four high-altitude balloon flights to begin in the summer of 2013, technologists at NASA’s Jet Propulsion Laboratory (JPL) in Pasadena, Calif., and Wallops Flight Facility in Wallops Island, Va., are preparing to test new deceleration devices that could replace current descent technologies for landing ever-larger payloads at higher elevations on Mars.

NASA hasn’t tested deceleration technologies supersonically since 1972 when it conducted four high-altitude tests of a supersonic parachute used during the Viking program. “We’ve been stuck with that design ever since,” said Mark Adler, NASA’s Low-Density Supersonic Decelerator (LDSD) program lead. NASA will use the same technology again this year when it delivers the Curiosity rover to Mars.

However, planetary landers of tomorrow will require much larger drag devices than any now in use. “What we need is new technology to slow larger, heavier landers from the supersonic speeds of atmospheric entry to subsonic ground-approach speeds,” Adler said. continue reading

Newfound Exoplanet May Turn to Dust: Planet’s Dust Cloud May...

Tue, 29 May 2012 09:53:00 -0700

Newfound Exoplanet May Turn to Dust: Planet’s Dust Cloud May Explain Strange Patterns of Light from Its Star |

Researchers at MIT, NASA and elsewhere have detected a possible planet, some 1,500 light years away, that appears to be evaporating under the blistering heat of its parent star. The scientists infer that a long tail of debris — much like the tail of a comet — is following the planet, and that this tail may tell the story of the planet’s disintegration. According to the team’s calculations, the tiny exoplanet, not much larger than Mercury, will completely disintegrate within 100 million years.

The team found that the dusty planet circles its parent star every 15 hours — one of the shortest planet orbits ever observed. Such a short orbit must be very tight and implies that the planet must be heated by its orange-hot parent star to a temperature of about 3,600 degrees Fahrenheit. Researchers hypothesize that rocky material at the surface of the planet melts and evaporates at such high temperatures, forming a wind that carries both gas and dust into space. Dense clouds of the dust trail the planet as it speeds around its star.

“We think this dust is made up of submicron-sized particles,” says co-author Saul Rappaport, a professor emeritus of physics at MIT. “It would be like looking through a Los Angeles smog.”

The group’s findings, published in the Astrophysical Journal, are based on data from the Kepler Observatory, a space-based telescope that surveys more than 160,000 stars in the Milky Way. The observatory records the brightness of each star at regular intervals; scientists then analyze the data for signs of new planets outside our own solar system. continue reading

Three-Telescope Interferometry Allows Astrophysicists to Observe...

Mon, 28 May 2012 17:57:12 -0700

Three-Telescope Interferometry Allows Astrophysicists to Observe How Black Holes Are Fueled |

By combining the light of three powerful infrared telescopes, an international research team has observed the active accretion phase of a supermassive black hole in the center of a galaxy tens of millions of light years away, a method that has yielded an unprecedented amount of data for such observations. The resolution at which they were able to observe this highly luminescent active galactic nucleus (AGN) has given them direct confirmation of how mass accretes onto black holes in centers of galaxies.

“This three-telescope interferometry is a major milestone toward directly imaging the growth phase of supermassive black holes,” said Sebastian Hoenig, a postdoctoral researcher at the UC Santa Barbara Department of Physics, and one of the astrophysicists who utilized this technique to observe the AGN at the center of galaxy NGC 3783. The observation was led by Gerd Weigelt, a director of the Max Planck Institute for Radio Astronomy in Bonn, Germany. continue reading

Deeper Look at Centaurus A | The strange galaxy Centaurus A is...

Mon, 28 May 2012 13:58:08 -0700

Deeper Look at Centaurus A |

The strange galaxy Centaurus A is pictured in a new image from the European Southern Observatory. With a total exposure time of more than 50 hours this is probably the deepest view of this peculiar and spectacular object every created. The image was produced by the Wide Field Imager of the MPG/ESO 2.2-metre telescope at ESO’s La Silla Observatory in Chile.

Centaurus A, also known as NGC 5128 [1], is a peculiar massive elliptical galaxy with a supermassive black hole at its heart. It lies about 12 million light-years away in the southern constellation of Centaurus (The Centaur) and has the distinction of being the most prominent radio galaxy in the sky. Astronomers think that the bright nucleus, strong radio emission and jet features of Centaurus A are produced by a central black hole with a mass of about 100 million times that of the Sun. Matter from the dense central parts of the galaxy releases vast amounts of energy as it falls towards the black hole.

This Wide Field Imager (WFI) picture allows us to appreciate the galaxy’s elliptical nature, which shows up as the elongated shape of the fainter outer parts. The glow that fills much of the picture comes from hundreds of billions of cooler and older stars. Unlike most elliptical galaxies, however, Centaurus A’s smooth shape is disturbed by a broad and patchy band of dark material that obscures the galaxy’s centre.

The dark band harbours large amounts of gas, dust and young stars. Bright young star clusters appear at the upper-right and lower-left edges of the band along with the red glow of star-forming clouds of hydrogen, whilst some isolated dust clouds are silhouetted against the stellar background. These features, and the prominent radio emission, are strong evidence that Centaurus A is the result of a merger between two galaxies. The dusty band is probably the mangled remains of a spiral galaxy in the process of being ripped apart by the gravitational pull of the giant elliptical galaxy. continue reading

Giant Galaxy-Packed Filament Revealed | A McGill-led research...

Mon, 28 May 2012 09:51:18 -0700

Giant Galaxy-Packed Filament Revealed |

A McGill-led research team using the Herschel Space Observatory has discovered a giant, galaxy-packed filament ablaze with billions of new stars. The filament connects two clusters of galaxies that, along with a third cluster, will smash together and give rise to one of the largest galaxy superclusters in the universe.

The filament is the first structure of its kind spied in a critical era of cosmic buildup when colossal collections of galaxies called superclusters began to take shape. The glowing galactic bridge offers astronomers a unique opportunity to explore how galaxies evolve and merge to form superclusters.

“We are excited about this filament, because we think the intense star formation we see in its galaxies is related to the consolidation of the surrounding supercluster,” said Kristen Coppin, a postdoctoral fellow in astrophysics at McGill and lead author of a new paper inAstrophysical Journal Letters.

“This luminous bridge of star formation gives us a snapshot of how the evolution of cosmic structure on very large scales affects the evolution of the individual galaxies trapped within it,” said Jim Geach, a co-author also based at McGill.

The intergalactic filament, containing hundreds of galaxies, spans 8 million light-years and links two of the three clusters that make up a supercluster known as RCS2319. This emerging supercluster is an exceptionally rare, distant object whose light has taken more than seven billion years to reach us. continue reading

How do we actually use numbers to measure the universe? That’s...

Sun, 27 May 2012 14:36:09 -0700

How do we actually use numbers to measure the universe? That’s precisely what the Royal Observatory Greenwich answers in this wonderful short animation, a teaser for a new exhibition titled Measuring the Universe: from the transit of Venus to the edge of the cosmos

SpaceX’s Dragon being pulled to the Space Station after...

Fri, 25 May 2012 13:06:00 -0700

SpaceX’s Dragon being pulled to the Space Station after grappling. 25 May 2012 will stand as a legendary day in the history of commercial spaceflight.

SpaceX’s Dragon approaching International Space Station...

Fri, 25 May 2012 11:51:55 -0700

SpaceX’s Dragon approaching International Space Station during earlier fly-under. (photo: NASA)

Beyond the High-Speed Hard Drive: Topological Insulators Open a...

Fri, 25 May 2012 09:49:58 -0700

Beyond the High-Speed Hard Drive: Topological Insulators Open a Path to Room-Temperature Spintronics |

Strange new materials experimentally identified just a few years ago are now driving research in condensed-matter physics around the world. First theorized and then discovered by researchers at the U.S. Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab) and their colleagues in other institutions, these “strong 3-D topological insulators” — TIs for short — are seemingly mundane semiconductors with startling properties. For starters, picture a good insulator on the inside that’s a good conductor on its surface — something like a copper-coated bowling ball.

A topological insulator’s surface is not an ordinary metal, however. The direction and spin of the surface electrons are locked together and change in concert. And perhaps the most surprising prediction is that the surface electrons cannot be scattered by defects or other perturbations and thus meet little or no resistance as they travel. In the jargon, the surface states remain “topologically protected” — they can’t scatter without breaking the rules of quantum mechanics.

“One way that electrons lose mobility is by scattering on phonons,” says Alexis Fedorov, staff scientist for beamline 12.0.1 of Berkeley Lab’s Advanced Light Source (ALS). Phonons are the quantized vibrational energy of crystalline materials, treated mathematically as particles. “Our recent work on a particularly promising topological insulator shows that its surface electrons hardly couple with phonons at all. So there’s no impediment to developing this TI for spintronics and other applications.” continue reading

NASA Survey Counts Potentially Hazardous Asteroids...

Thu, 24 May 2012 18:01:59 -0700

NASA Survey Counts Potentially Hazardous Asteroids |

Observations from NASA’s Wide-field Infrared Survey Explorer (WISE) have led to the best assessment yet of our solar system’s population of potentially hazardous asteroids. The results reveal new information about their total numbers, origins and the possible dangers they may pose.

Potentially hazardous asteroids, or PHAs, are a subset of the larger group of near-Earth asteroids. The PHAs have the closest orbits to Earth’s, coming within five million miles (about eight million kilometers), and they are big enough to survive passing through Earth’s atmosphere and cause damage on a regional, or greater, scale.

The new results come from the asteroid-hunting portion of the WISE mission, called NEOWISE. The project sampled 107 PHAs to make predictions about the entire population as a whole. Findings indicate there are roughly 4,700 PHAs, plus or minus 1,500, with diameters larger than 330 feet (about 100 meters). So far, an estimated 20 to 30 percent of these objects have been found.

While previous estimates of PHAs predicted similar numbers, they were rough approximations. NEOWISE has generated a more credible estimate of the objects’ total numbers and sizes. continue reading

Colossal Superflares Erupt from Sun-Like Stars | Stars like our...

Thu, 24 May 2012 14:01:43 -0700

Colossal Superflares Erupt from Sun-Like Stars |

Stars like our sun can release “superflares,” explosions of up to 10,000 times more energy than the solar flares seen from our sun, researchers say.

However, it looks unlikely that our sun currently has superflares, scientists added.

Astronomers have previously detected superflares from a variety of star types, which release bursts that have 10 to 10,000 times more energy than the largest solar flare ever detected from our sun. Scientists wanted to know how common these outbursts might be from stars like the sun — those with masses and temperatures similar to our star. Even normal solar flares can damage satellites, endanger astronauts and wreak havoc on electrical grids on Earth, suggesting that superflares might be catastrophic to life on Earth.

Dragon Fire The SpaceX Falcon 9 rocket soared into space from...

Thu, 24 May 2012 09:59:06 -0700

Dragon Fire

The SpaceX Falcon 9 rocket soared into space from Space Launch Complex-40 on Cape Canaveral Air Force Station in Florida, carrying the Dragon capsule to orbit at 3:44 a.m. EDT on Tuesday, May 22, 2012. The launch is the company’s second demonstration test flight for NASA’s Commercial Orbital Transportation Services, or COTS, Program.

During the flight, there will be a series of check-out procedures to test and prove Dragon’s systems, including rendezvous and berthing with the International Space Station. If the capsule performs as planned, the cargo and experiments it is carrying will be transferred to the station.

Watch the launch footage: http://youtu.be/dlpk-gOkY6M

via unknownskywalker

Astronaut Don Pettit on the International Space Station took...

Wed, 23 May 2012 14:01:20 -0700

Astronaut Don Pettit on the International Space Station took this picture during the annular/partial eclipse, looking back on Earth tocapture the shadow of the Moon.

SpaceX’s Dragon Capsule Roars to Space Station...

Wed, 23 May 2012 09:57:40 -0700

SpaceX’s Dragon Capsule Roars to Space Station |

SpaceX’s first space station-bound Dragon spacecraft, flying atop a Falcon 9 rocket, launched early yesterday morning. Liftoff occurred on May 22, 2012 from Cape Canaveral Air Force Station.

Masten Space System’s Katana KA5S Engine Firing | Masten...

Tue, 22 May 2012 18:01:43 -0700

Masten Space System’s Katana KA5S Engine Firing |

Masten Space Systems conducted a 2-sec shakedown test on May 18th, 2012 of a new engine test trailer with a Katana class heatsink engine, the KA5S. Engines in the Katana class can produce up to 4000 lbs of thrust. Read more about Masten Space Systems.

ATK to Launch Private Space Taxi by 2015 | The aerospace company...

Tue, 22 May 2012 14:01:37 -0700

ATK to Launch Private Space Taxi by 2015 |

The aerospace company that built the solid rocket boosters for NASA’s space shuttle fleet announced plans today (May 9) to develop its own private launch system — a spaceship and rocket — to fly astronauts to and from low-Earth orbit. The first manned flight could launch in about three years, company officials said.

Utah-based Alliant Techsystems, or ATK, announced the new project here at the first Spacecraft Technology Expo, where thousands of government and industry officials have gathered to discuss innovative new technologies and the future of human spaceflight.

ATK had already been working on a new private rocket, called Liberty, which it submitted as a contender in the second round of NASA’s Commercial Crew Development program last year. Ultimately, the Liberty rocket was not selected to receive funding, but ATK continued development of the booster under an unfunded Space Act Agreement with NASA. As part of this arrangement, NASA shares its expertise in designing and testing the rocket but does not provide money for the project.

Now, ATK has unveiled plans for a complete launch system centered around the Liberty rocket. The design includes a space capsule to carry passengers to destinations in low-Earth orbit, such as the International Space Station, said Kent Rominger, vice president and program manager for Liberty.continue reading