thepuzzler
October 20th, 2006, 01:29 AM
A real invisibility cloak? Wizard!
By Lewis Smith
British professor's theory has become a reality as US scientists develop a vanishing act:
IT BEGAN as just a wizard idea from a British scientist. Yesterday it became a reality.
And reality began to disappear.
Following in the footsteps of Harry Potter, it was revealed that the world’s first invisibility cloak has been tested in America. So far the device is rather limited — it is 5in (13cm) wide and can hide an object only from microwave beams.
But the principle established by Sir John Pendry, a professor at Imperial College, London, has been proved to work and in the next five years there are hopes that total invisibility may become possible for larger objects. Tanks, for example.
Laboratory experiments at Duke University, North Carolina, were funded by the US intelligence community. Using copper rings and metamaterials — artifical composites — arranged in concentric circles, it was shown that microwave radiation can be deflected past an object just as water will flow past an obstacle.
When a beam was aimed at the device, sensors were unable to “see” the object hidden in the middle because the microwaves were not bounced back.
http://i5.photobucket.com/albums/y155/foot226/invis.jpg
“Our cloak allows a concealed volume, plus the cloak, to appear to have properties similar to free space when viewed externally,” Professor David Smith, of Duke University, said. “The cloak deflects microwave beams so they flow around a ‘hidden’ object, making it appear almost as if nothing were there at all. The waves’ movement is similar to river water flowing around a smooth rock.”
The cloaking device, reported in Science Express, the online version of the journal Science, was designed by David Schurig, of Duke University, who said that it had the effect of warping space. “You cannot easily warp space but you can achieve the same effect on electromagnetic fields using materials with the right response,” he said. “The required materials are quite complex.”
He compared the deflection of the microwaves to pushing a knitting needle into fabric. The threads are pushed aside but do not break.
The US team produced the cloak according to electromagnetic specifications determined by a design theory proposed by Sir John, 63. The artificial composites in metamaterials react with electromagnetic waves in a way that natural materials would not.
Sir John said: “The real challenge was to make the unusual materials needed for a working device. It’s all been done in a timescale much shorter than I had envisaged. This cloaking device is just a demonstration showing that you can get radiation where you want it to be.
Read the rest here. (http://www.timesonline.co.uk/article/0,,2-2412995,00.html)
By Lewis Smith
British professor's theory has become a reality as US scientists develop a vanishing act:
IT BEGAN as just a wizard idea from a British scientist. Yesterday it became a reality.
And reality began to disappear.
Following in the footsteps of Harry Potter, it was revealed that the world’s first invisibility cloak has been tested in America. So far the device is rather limited — it is 5in (13cm) wide and can hide an object only from microwave beams.
But the principle established by Sir John Pendry, a professor at Imperial College, London, has been proved to work and in the next five years there are hopes that total invisibility may become possible for larger objects. Tanks, for example.
Laboratory experiments at Duke University, North Carolina, were funded by the US intelligence community. Using copper rings and metamaterials — artifical composites — arranged in concentric circles, it was shown that microwave radiation can be deflected past an object just as water will flow past an obstacle.
When a beam was aimed at the device, sensors were unable to “see” the object hidden in the middle because the microwaves were not bounced back.
http://i5.photobucket.com/albums/y155/foot226/invis.jpg
“Our cloak allows a concealed volume, plus the cloak, to appear to have properties similar to free space when viewed externally,” Professor David Smith, of Duke University, said. “The cloak deflects microwave beams so they flow around a ‘hidden’ object, making it appear almost as if nothing were there at all. The waves’ movement is similar to river water flowing around a smooth rock.”
The cloaking device, reported in Science Express, the online version of the journal Science, was designed by David Schurig, of Duke University, who said that it had the effect of warping space. “You cannot easily warp space but you can achieve the same effect on electromagnetic fields using materials with the right response,” he said. “The required materials are quite complex.”
He compared the deflection of the microwaves to pushing a knitting needle into fabric. The threads are pushed aside but do not break.
The US team produced the cloak according to electromagnetic specifications determined by a design theory proposed by Sir John, 63. The artificial composites in metamaterials react with electromagnetic waves in a way that natural materials would not.
Sir John said: “The real challenge was to make the unusual materials needed for a working device. It’s all been done in a timescale much shorter than I had envisaged. This cloaking device is just a demonstration showing that you can get radiation where you want it to be.
Read the rest here. (http://www.timesonline.co.uk/article/0,,2-2412995,00.html)