The Shadow © C. Nast Publications
The Fox © Alex Toth
Black Canary © DC Comics
Sunday, May 28, 2006
Alex Toth: 1928-2006
The Shadow © C. Nast Publications
The Fox © Alex Toth
Black Canary © DC Comics
5th Dimensional 'Braneworld'
Scientists have developed a mathematical framework they say will enable astronomers to test a new five-dimensional theory of gravity that competes with Einstein's General Theory of Relativity.
Charles R. Keeton of Rutgers and Arlie O. Petters of Duke base their work on a recent theory called the type II Randall-Sundrum braneworld gravity model. The theory holds that the visible universe is a membrane (hence "braneworld") embedded within a larger universe, much like a strand of filmy seaweed floating in the ocean. The "braneworld universe" has five dimensions -- four spatial dimensions plus time -- compared with the four dimensions -- three spatial, plus time -- laid out in the General Theory of Relativity.
The braneworld theory predicts that relatively small "black holes" created in the early universe have survived to the present. The black holes, with mass similar to a tiny asteroid, would be part of the "dark matter" in the universe. As the name suggests, dark matter does not emit or reflect light, but does exert a gravitational force.
"A good place to look for gravitational lensing by braneworld black holes is in bursts of gamma rays coming to Earth," Keeton said. These gamma-ray bursts are thought to be produced by enormous explosions throughout the universe. Such bursts from outer space were discovered inadvertently by the U.S. Air Force in the 1960s.
"If the braneworld theory is correct," they said, "there should be many, many more braneworld black holes throughout the universe, each carrying the signature of a fourth dimension of space."
Charles R. Keeton of Rutgers and Arlie O. Petters of Duke base their work on a recent theory called the type II Randall-Sundrum braneworld gravity model. The theory holds that the visible universe is a membrane (hence "braneworld") embedded within a larger universe, much like a strand of filmy seaweed floating in the ocean. The "braneworld universe" has five dimensions -- four spatial dimensions plus time -- compared with the four dimensions -- three spatial, plus time -- laid out in the General Theory of Relativity.
The braneworld theory predicts that relatively small "black holes" created in the early universe have survived to the present. The black holes, with mass similar to a tiny asteroid, would be part of the "dark matter" in the universe. As the name suggests, dark matter does not emit or reflect light, but does exert a gravitational force.
"If the braneworld theory is correct," they said, "there should be many, many more braneworld black holes throughout the universe, each carrying the signature of a fourth dimension of space."
Robot hand Controlled By Thought
A robotic hand controlled by the power of thought alone has been demonstrated by researchers in Japan.
The robotic hand mimics the movements of a person's real hand, based on real-time functional magnetic resonance imaging (fMRI) of their brain activity. It marks another landmark in the advance towards prosthetics and computers that can be operating by thought alone.
The system was developed by Yukiyasu Kamitani and colleagues from the ATR Computational Neuroscience Laboratories in Kyoto, and researchers from the Honda Research Institute in Saitama.
Subjects lay inside an MRI scanner and were asked to make "rock, paper, scissor" shapes with their right hand. As they did this, the MRI scanner recorded brain activity during the formation of each shape and fed this data to a connected computer. After a short training period, the computer was able to recognise the brain activity associated with each shape and command the robotic appendage do the same.
The robotic hand mimics the movements of a person's real hand, based on real-time functional magnetic resonance imaging (fMRI) of their brain activity. It marks another landmark in the advance towards prosthetics and computers that can be operating by thought alone.
The system was developed by Yukiyasu Kamitani and colleagues from the ATR Computational Neuroscience Laboratories in Kyoto, and researchers from the Honda Research Institute in Saitama.
Subjects lay inside an MRI scanner and were asked to make "rock, paper, scissor" shapes with their right hand. As they did this, the MRI scanner recorded brain activity during the formation of each shape and fed this data to a connected computer. After a short training period, the computer was able to recognise the brain activity associated with each shape and command the robotic appendage do the same.
Friday, May 26, 2006
Leeuwenhoek Sees Animalcules
On this day in
1676, Antonie van Leeuwenhoek applied his hobby of making microscopes from his own handmade lenses to observe some water running off a roof during a heavy rainstorm. He finds that it contains, in his words, "very little animalcules." The life he has found in the runoff water is not present in pure rainwater. This was a fundamental discovery, for it showed that the bacteria and one-celled animals did not fall from the sky. Link
Thursday, May 25, 2006
Invisible Man Almost Visible
Two prescriptions for an invisibility cloak have been unveiled by physicists in the United Kingdom and the United States. The researchers say that in principle the technologies needed for building these devices already exist. "Invisibility is visibly close," says Ulf Leonhardt of the University of St Andrews in Scotland, one of the researchers behind the proposals.
(Click images to enlarge)He and John Pendry of Imperial College London, UK, and their co-workers have independently described similar ways to create an invisible 'hole' in space, inside which objects can be hidden. They say it is possible to guide light around the hole, rather like water flowing around a rock in a river, so that the object inside it cannot be seen.
Light rays are bent when they pass between materials with different refractive indices, such as air and water. But bending light so that it passes round a region of space and emerges travelling along the same line as it was initially is a difficult trick, requiring an invisibility cloak made from materials with a 'tunable' refractive index.
Such substances have been made, in the form of so-called metamaterials. These are built from rings or coils of metal wire, etched into printed circuit boards and glued together, which act as antennae that interact with the electromagnetic field of incoming light and modify the paths the light takes. Such metamaterials can have bizarre optical properties: for example, having negative refractive index, so that they bend light the 'wrong' way.
(Click images to enlarge)
Light rays are bent when they pass between materials with different refractive indices, such as air and water. But bending light so that it passes round a region of space and emerges travelling along the same line as it was initially is a difficult trick, requiring an invisibility cloak made from materials with a 'tunable' refractive index.
Such substances have been made, in the form of so-called metamaterials. These are built from rings or coils of metal wire, etched into printed circuit boards and glued together, which act as antennae that interact with the electromagnetic field of incoming light and modify the paths the light takes. Such metamaterials can have bizarre optical properties: for example, having negative refractive index, so that they bend light the 'wrong' way.
Wednesday, May 24, 2006
Dracorex hogwartsia
The name Dracorex hogwartsia, from the Latin words draco (meaning dragon), rex (meaning king), and hogwartsia (after the fictional Hogwarts School for Witchcraft and Wizardry created by J.K. Rowling).The nearly complete skull was discovered by three friends; Steve Saulsbury, Patrick Saulsbury and Brian Buckmeier, all from Sioux City, Iowa. They found it during a fossil collecting trip in South Dakota and donated it to The Children’s Museum of Indianapolis. When it was brought to the museum’s Paleo Prep Lab for cleaning and studying, it was little more than a box of parts. It took two years to patiently glue together the many fragments and restore the skull.
Tuesday, May 23, 2006
Flesh-Eating Disease Explained
Today in 1994, an explanation for a "deadly flesh-eating bug" outbreak in England was offered by British doctors. The disease was attributed to a cluster of unusually intense infections by the common Steptococcus bacterium. The people in Gloucestershire had been injured by a toxin that dissolved flesh and fat which came from the excessive bacteria's attack. Normally, Steptococcus is associated with simple and common sore throats and fever. Link Raising the dead is as easy as pie in the 30th century, but there is that whole 'monkey's paw' curse thing to deal with (see video above).
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