Archive for January, 2009
DRIVING through the countryside south of Hanover, it would be easy to miss the GEO600 experiment. From the outside, it doesn’t look much: in the corner of a field stands an assortment of boxy temporary buildings, from which two long trenches emerge, at a right angle to each other, covered with corrugated iron. Underneath the metal sheets, however, lies a detector that stretches for 600 metres.
For the past seven years, this German set-up has been looking for gravitational waves – ripples in space-time thrown off by super-dense astronomical objects such as neutron stars and black holes. GEO600 has not detected any gravitational waves so far, but it might inadvertently have made the most important discovery in physics for half a century.
For many months, the GEO600 team-members had been scratching their heads over inexplicable noise that is plaguing their giant detector. Then, out of the blue, a researcher approached them with an explanation. In fact, he had even predicted the noise before he knew they were detecting it. According to Craig Hogan, a physicist at the Fermilab particle physics lab in Batavia, Illinois, GEO600 has stumbled upon the fundamental limit of space-time – the point where space-time stops behaving like the smooth continuum Einstein described and instead dissolves into “grains”, just as a newspaper photograph dissolves into dots as you zoom in. “It looks like GEO600 is being buffeted by the microscopic quantum convulsions of space-time,” says Hogan.
If this doesn’t blow your socks off, then Hogan, who has just been appointed director of Fermilab’s Center for Particle Astrophysics, has an even bigger shock in store: “If the GEO600 result is what I suspect it is, then we are all living in a giant cosmic hologram.”
The idea that we live in a hologram probably sounds absurd, but it is a natural extension of our best understanding of black holes, and something with a pretty firm theoretical footing. It has also been surprisingly helpful for physicists wrestling with theories of how the universe works at its most fundamental level.
The holograms you find on credit cards and banknotes are etched on two-dimensional plastic films. When light bounces off them, it recreates the appearance of a 3D image. In the 1990s physicists Leonard Susskind and Nobel prizewinner Gerard ‘t Hooft suggested that the same principle might apply to the universe as a whole. Our everyday experience might itself be a holographic projection of physical processes that take place on a distant, 2D surface.
The “holographic principle” challenges our sensibilities. It seems hard to believe that you woke up, brushed your teeth and are reading this article because of something happening on the boundary of the universe. No one knows what it would mean for us if we really do live in a hologram, yet theorists have good reasons to believe that many aspects of the holographic principle are true.
Susskind and ‘t Hooft’s remarkable idea was motivated by ground-breaking work on black holes by Jacob Bekenstein of the Hebrew University of Jerusalem in Israel and Stephen Hawking at the University of Cambridge. In the mid-1970s, Hawking showed that black holes are in fact not entirely “black” but instead slowly emit radiation, which causes them to evaporate and eventually disappear. This poses a puzzle, because Hawking radiation does not convey any information about the interior of a black hole. When the black hole has gone, all the information about the star that collapsed to form the black hole has vanished, which contradicts the widely affirmed principle that information cannot be destroyed. This is known as the black hole information paradox.
Bekenstein’s work provided an important clue in resolving the paradox. He discovered that a black hole’s entropy – which is synonymous with its information content – is proportional to the surface area of its event horizon. This is the theoretical surface that cloaks the black hole and marks the point of no return for infalling matter or light. Theorists have since shown that microscopic quantum ripples at the event horizon can encode the information inside the black hole, so there is no mysterious information loss as the black hole evaporates.
Crucially, this provides a deep physical insight: the 3D information about a precursor star can be completely encoded in the 2D horizon of the subsequent black hole – not unlike the 3D image of an object being encoded in a 2D hologram. Susskind and ‘t Hooft extended the insight to the universe as a whole on the basis that the cosmos has a horizon too – the boundary from beyond which light has not had time to reach us in the 13.7-billion-year lifespan of the universe. What’s more, work by several string theorists, most notably Juan Maldacena at the Institute for Advanced Study in Princeton, has confirmed that the idea is on the right track. He showed that the physics inside a hypothetical universe with five dimensions and shaped like a Pringle is the same as the physics taking place on the four-dimensional boundary.
Full Article | New Scientist, Our world may be a giant hologram
Electronic aids that help blind and partially sighted people navigate and interact with their environment – such as ultrasound canes and voice-enabled GPS devices – are becoming more widely available. But a new device could take such interaction to the next level.
George Stetten, a bioengineer at the University of Pittsburgh, has come up with the idea of a tiny video camera that sits at the end of a finger (see image, right) and connects to a portable computer that can analyse the footage and flag up objects of interest.
The camera mounting could also vibrate to provide physical feedback from the computer to signal it has seen something significant. A warning could be given when the camera spots a nearby obstacle, like a wall or the edge of a table, and it could even trace out the shape to guide the user past.
Image processing makes it possible for the system to recognize very specific objects. Stetten’s patent says that, amongst other things, the computer could recognize light switches or other controls from a distance. The user could be steered towards a switch using physical feedback, or given the option to activate it remotely.
The capabilities of such a system are limited only by imagination, says Stetten, and has the potential to give blind and partially sighted people much greater control and interaction with the world around them. In fact, a portable system able to look for objects for you could offer benefits to fully sighted people too.
Read the full fingercam remote control patent application.
Source | New Scientist
Japanese scientists have successfully cloned a prize beef cow more than 13 years after it died, it was announced on January 6. The legendary steer — named “Yasufuku” in his first life (1980-1993) — is regarded as the father of Hida beef, a high-quality meat from Gifu prefecture famous for its marbled texture and rich flavor.
During his 13-year life, the prize bull’s sperm was used to sire 40,000 calves, helping to establish Hida as a high-class brand of beef. It is believed that more than 30% of the nation’s Japanese black cattle can trace their roots back to Yasufuku.
To produce the clones, researchers from the Gifu Prefectural Livestock Research Institute and Kinki University (Osaka prefecture) employed a somatic cell nuclear transfer method using the nuclei of cells extracted from the bull’s testicles, which had spent 13 years in deep-freeze. The first clone of Yasufuku was created in 2007. In all, four clones of Yasufuku have been born, although one died from complications after birth.
The results — which were scheduled to be published in the US journal PLoS ONE on January 8 — suggest it is possible to “resurrect” animals valued for their high-quality meat, long after they have died. Some suggest the cloning method can also be used resurrect prize pigs and horses.
The rebirth of Yasufuku follows the recent success of another cloning experiment involving mammals held in long-term frozen storage. In November 2008, a RIKEN research team cloned a mouse from a carcass that spent 16 years in a freezer.
Teruhiko Wakayama, the RIKEN genetic engineer who led the effort to clone the frozen mouse last year, reacted to the news of the cloned frozen cow. “I was surprised to learn that the researchers found usable cells in the frozen tissue,” said Wakayama. “[Their findings suggest] it is now possible to clone cows from delicious beef found on the supermarket shelf.”
News of this latest cloning success comes as the Japanese government grapples with whether or not to allow cloned animal products into the food chain. The Cabinet Office’s Food Safety Commission is currently looking at scientific data from a variety of Japanese and foreign sources in an attempt to evaluate the safety of cloned animal products. The commission is scheduled to present its decision to the Ministry of Health, Labor and Welfare later this year. Lawmakers will then have the final say on whether or not to approve the sale of cloned meat to Japanese consumers.
In 2008 (between January and September), researchers in Japan are known to have created 557 somatic cell cow clones. In response to consumer distrust of cloned meat, the Ministry of Agriculture, Forestry and Fisheries (MAFF) currently requests research institutions to take voluntary measures to prevent cloned cows from ending up in the food supply.
Source | Pink Tentacle