Naked Science Forum
Non Life Sciences => Physics, Astronomy & Cosmology => Topic started by: thedoc on 16/07/2013 00:30:01
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Adam Raphael asked the Naked Scientists:
Hi Naked Scientists!
I listen to the show all the time on podcasts from my home-away-from-home, here in Taiwan.
I just saw an article on a Canadian company, http://www.hyperstealth.com/Quantum-Stealth/who claim to have developed a visible light invisibility cloak.
I'm very skeptical about this, from the tech, down to the look of the website... but CNN, Discovery etc. have been reporting on it.
Is this just a con designed to drum up buisness that networks have believed? Or is there anything behind this (I know Chris loves a terrible pun to use as a segue)?
Thanks,
Adam Raphael
What do you think?
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I think it's nonsense. I'm reminded of Bruce DePalma's N-machine that was being discussed on talk radio in the early 1990's. It was supposed be a perpetual motion machine. It was a simple rotating magnetic with a copper plate attached to one end. It's also known as a homopolar generator and can be found in certain electrodynamics textbooks. Supposedly one needs to understand relativity to understand its operation. A favorite quote of mine is from a philosophy of science class I took as an undergrad which said that nonsense can have some surprising twists to it sometimes and can be entertaining in a certain sense. So with that in mind I came I looked into it. And sure enough I was entertained by it. I learned that on does indeed need a good grasp on relativistic electrodynamics to understand it.
I created a web page to describe the physics of the device at
http://home.comcast.net/~peter.m.brown/em/rotating_magnet.htm
But the claim that it was a perpetual motion machine was garbage. The author was a fraud and the people who have web pages about it seem too afraid to respond to comments on them. But a lot of people called the radio station claiming that they worked and that implied that they were getting out more energy that was being put in. This is like your current subject. It too is crap.
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I agree with Pete. The website advertises how amazing the technology is, yet at the same time claims they can't demonstrate it or describe it in detail due to "security issues," which is a bit too convenient of a way to get out of having to prove it works... When military security issues are involved, you're generally not allowed to put up websites advertising the technology.
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I think it's nonsense. I'm reminded of Bruce DePalma's N-machine that was being discussed on talk radio in the early 1990's. It was supposed be a perpetual motion machine. It was a simple rotating magnetic with a copper plate attached to one end. It's also known as a homopolar generator and can be found in certain electrodynamics textbooks. Supposedly one needs to understand relativity to understand its operation. A favorite quote of mine is from a philosophy of science class I took as an undergrad which said that nonsense can have some surprising twists to it sometimes and can be entertaining in a certain sense. So with that in mind I came I looked into it. And sure enough I was entertained by it. I learned that on does indeed need a good grasp on relativistic electrodynamics to understand it.
I created a web page to describe the physics of the device at
http://home.comcast.net/~peter.m.brown/em/rotating_magnet.htm
But the claim that it was a perpetual motion machine was garbage. The author was a fraud and the people who have web pages about it seem too afraid to respond to comments on them. But a lot of people called the radio station claiming that they worked and that implied that they were getting out more energy that was being put in. This is like your current subject. It too is crap.
Great answer! Cheers.
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Maybe it was this they meant?
"HyperStealth CEO Guy Cramer says the Quantum Stealth design (above) builds on his company's previous computer-generated digital patterns by using fractals that mimic the distribution of colour in natural surroundings. This makes the wearer practically invisible, says Cramer: "It provides that few extra seconds of concealment." Some of the details and technical features of HyperStealth's work cannot be revealed for reasons of military secrecy, and only mock-up pictures are available --"
Camouflage using some algorithm creating a pattern. As for the rest of it I agree. Anyone stating that he can hide a man by making light 'go around' him gotta be bs, so far that is :)
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They were able to bend radio and micro waves so why not visible light waves. I bet I know how it could be done, the way they make radio wave bending "meta-materials" is by making tiny micro patterns that cover the whole material usually made of silicon but each pattern is like 500 microns large and all you have to do is make the patterns smaller in-order to bend higher frequency light, you would need to make micro patterns as small as 5 or 10 microns to be able to bend visible light, which is virtually impossible to make with a silicon micro engraver, you would need to make the micro patters out of conductive molecules inside a lattice that is insulating then you would need to lightly jolt the materials when they are soaked in water. then you would get invisibility
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Metamaterials have a couple of problems. The first is manufacturing: they have to actually be around 100 nanometers (0.1 microns), not 5 or 10 microns for visible light. This is very difficult to do on a large scale. Some natural materials can do some cloaking, but only for certain polarizations of light, which means they wouldn't work well on unpolarized, natural light. Finally, due to a property of matter called dispersion, they only work for certain frequencies of light. So it might cloak well in the red but not for violet light.