Making a Liquid Invisibility Cloak 93
Researchers at Fudan University in Shanghai, China are proposing a method which could lead to the first soft, tunable metamaterial, the key ingredient in building an invisibility device. "The fluid proposed by Ji-Ping Huang of Fudan University in Shanghai, China, and colleagues, contains magnetite balls 10 nanometers in diameter, coated with a 5-nanometer-thick layer of silver, possibly with polymer chains attached to keep them from clumping. In the absence of a magnetic field, such nanoparticles would simply float around in the water, but if a field were introduced, the particles would self-assemble into chains whose lengths depend on the strength of the field, and which can also attract one another to form thicker columns. The chains and columns would lie along the direction of the magnetic field. If they were oriented vertically in a pool of water, light striking the surface would refract negatively – bent in way that no natural material can manage."
Liquid Invisibility Cloak? (Score:3, Funny)
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No, no, that's the power of invincibility. But can I get that without the tea or lime. I don't need any of that girlie crap thinning out my liquor.
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[sound of crickets]
Did someone say something?
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Oh ho ho ho ho!
I didn't see that one coming.
Did that joke have an invisibility cloak too?
Re:Let's get this over with... (Score:5, Funny)
Apparently you saw right through that one.
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We already have those. I change channels on TV with them every night. And, be damned if you're going to take my magic stick away from me. Taking it away is like taking food from an angry dog. I don't care if you don't want to watch the Mystery Science Theater marathon, *I* have the magic stick!
Re:anonymous coward (Score:5, Funny)
As a matter of fact, my "magic stick" is superior to yours, since I can cede control of it to my wife and still watch MST3K marathons.
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I think I understand your confusion. But it's not exactly appropriate to call Mjollnir (Thor's Hammer), a "magic stick". That's like calling a lightning bolt sent from high above Mount Olympus by Zeus just a "pretty light".
Magic stick works the electronics.
Mjollnir bangs your wife. :)
Future Commercial Success Guaranteed (Score:1)
What is so great about the invisibility cloak? (Score:4, Funny)
Re:What is so great about the invisibility cloak? (Score:5, Funny)
Um no you are a sick mind... It is for the Woman's locker room.
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Not to stomp on ur parade.... (Score:1, Interesting)
Actually no, just the fact of being invisible. In order to be invisible you have to refract all the light that would normally hit the object being invisible, meaning it would be in absolute dark. You could be invisible in the girls (or guys for the /.ers so persueded) shower room, but you couldn't see a blasted thing. Any lighted object within the cloak could also, possibly, leak out giving away your concealment. So even IF (a big if) the use of, say, an infrared camera, would allow you to see through
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Your average slashdot reader is:
Re:What is so great about the invisibility cloak? (Score:4, Insightful)
Bah. thats just security through obscurity.
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Slightly better than obscurity... being invisible is a little different from being obscure :)
Either way, invisibility is all you need to prevent girlfriend from walking in and seeing you watching porn.
Oh wait... slashdot.... uh... neighbors?
Anyways, a physical attacker needs to be able to see your machine before they can steal it.
If they can't see where it's located, they won't be able to get in and grab it before the burglar suppression system goes off and knocks them out.
They won't be able to
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"In need of a cloaking device, for that one last piece of the security puzzle (keeping the machine safe from physical hackers)"
No! No! that would be security by obscurity!
Countermeasure (Score:3, Funny)
You can see through them with beer goggles.
Just in time... (Score:2)
...for the era of Chinese domination.
Theoretical material with exotic optical effects (Score:1)
Re:Theoretical material with exotic optical effect (Score:4, Funny)
Similarly, a hunk of silicon with strange electrical properties isn't a computer. And yet, the former is very useful if you want to build the latter.
Do you, like, just not understand how science works?
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Similarly, a hunk of silicon with strange electrical properties isn't a computer. And yet, the former is very useful if you want to build the latter.
Do you, like, just not understand how science works?
My ire was directed at the reporting, not the discovery or researchers (who I wish good luck).
Calling this discovery "Making a liquid invisibility cloak" is like calling the discovery of a new, slightly higher temperature superconductor "Making warp-capable flying cars".
Maybe sensational reporting of just about everything (eg the LHC) is causing the public's lack of affinity for science. All they see is hundreds of 'broken promises' made by the media about fantastic whizz-bang technologies that the research
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Humans are dreamers above anything.
A good thing too , otherwise there wouldn't be any inventions.
The problem is , just an idea isn't good enough : you need a plan to put it into practice , and you need money in order to bring it into a workable product.
That means you have to find investors, and 'Liquid Invisibility Cloak' sells better than 'Theoretical material with exotic optical effect' .
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It's sitting right in front of you, but it's covered with an invisibility cloak.
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It's impossible to actually create an SEP field, because of course the ideas, research and manufacture are all SEP !
Isn't this overkill? (Score:2, Insightful)
I mean, Aquaman is enough of a badass already, isn't he?
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I mean, Aquaman is enough of a badass already, isn't he?
Monarch, super-strength, harpoon, magic water control, now invisibility. These things are _necessary_ to combat the Superfriends Aquaman.
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I'm more concerned about invisible sharks with lasers on their heads.
Only works from one perspective? (Score:3, Funny)
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Theory blazes the trail, but it can't pave the road
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> But a real invisibility cloak has to detect the direction of every photon
> striking it and deliver that proton in the same direction out the exact
> opposite side of the cloak, doesn't it?
And exactly that is theoretically possible with metamaterials. In any case, a cloak could be useful even if it only works over perhaps 120 degrees.
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And as far as it's sense of sight is concerned, the rest of the world would not exist.
Douglas Adams had a jump on this one... "a beast so stupid it believed that if you cannot see it, it cannot see you"
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And as far as it's sense of sight is concerned, the rest of the world would not exist.
Ever heard of view-holes? We only need about a quarter-inch diameter hole to get a nearly 180 degree field of view. Cameras can do the exact same thing, often times with less.
I don't know if you know this, but it's a lot harder to see a little dot a quarter-inch in diameter floating in space than it is to see a 6' tall person or a 10' by 15' tank, or whatever the hell ends up getting cloaked.
Taking care of visibility out is downright EASY. You simply need a very small (in size) light collector just outsi
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Glad to hear your advanced research is going so well. So you'll be able to move out of your mom's basement soon?
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OK, commence with the sexual innuendo jokes.
This is the correct url (Score:4, Informative)
Very cool link, there was just a typo in your url.
The correct url is http://www.moillusions.com/2007/12/julian-beevers-new-3d-sidewalk.html [moillusions.com]
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Wow. Now that is invisible. A picture that generates an HTTP 404 error when you look at it is cool, but of course there is always the danger that someone will just come along and add an "l" at the end of it. (see http://www.moillusions.com/2007/12/julian-beevers-new-3d-sidewalk.html [moillusions.com] , not .htm ).
Disclaimer: I only clicked on it because I thought it said Jullie-Ann Beavers. Needless to say I was rather disappointed after def
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see http://www.moillusions.com/2007/12/julian-beevers-new-3d-sidewalk.html [moillusions.com]
I just can't see it.. but then maybe because I've only got one eye.
Sorry for the lack of photos! (Score:2, Funny)
We poured the material in a jar so that you could see the effects, but unfortunately we now seem to have misplaced it. We'll update as soon as we found it!
negative index != invisibility (Score:5, Informative)
All metamaterials are not created equal. A metamaterial is an electromagnetic medium created by a composite of tiny (very subwavelength) constituent structures, put together in such away that longer wavelengths see an "average" material with properties very different from those of the constituents. Usually, the goal is to use resonant effects in the microscopic constituents to make a material that is effectively very different from naturally occuring EM media. But this can be done for many different purposes.
A negative-refractive metamaterial is designed to have an effective "negative" index of refraction, which makes Snell's law (refraction) bend backwards, and can potentially be used for flat-lens near-field imaging, subwavelength imaging (again only in the near field), etcetera. The main practical difficulty here is that the most interesting applications of negative-index materials are in the visible or infrared regime, but negative-index metamaterials rely on metallic constitutents and metals become very lossy at those wavelengths.
Recent "invisibility" cloak proposals are based on the observation that there is a one-to-one mapping between transforming space to "curve around" the object being cloaked and keeping space the same and transforming the materials. So, if you can make materials with certain properties, they could effectively cloak an object by causing all the light rays to curve around the object just as if space were curved. Although this is mathematically quite beautiful, there are many practical obstacles to making this a reality. The proposal is to make the required materials via metamaterials, but these are NOT negative-index metamaterials. The required materials theoretically tend to require some singularities (points where the index blows up or vanishes), and trying to approximate that in practice inevitably involves losses which spoil the cloaking. In general, the bigger the object to be cloaked compared to the wavelength, the smaller the losses have to be, and the narrower the bandwidth is going to be. When you work out the numbers, you see that this is why all the experimental demonstrations of cloaking have only "cloaked" (reduced the scattering crosssection, but not to zero) objects that were a wavelength or two in diameter. Cloaking macroscopic objects at visible wavelengths is a fantasy because the material requirements are insane. The only remotely practical prospects seem to be cloaking objects on the ground (which makes things technically easier because the coordinate transformations are nonsingular) to long-wavelength radiation, e.g. cloaking something against radio waves.
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All that interesting information, and yet no car analogy. C-
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Ministry of Magic needs to know. (Score:1)
It's all about Ninja's, DUH! (Score:1)
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Star Wars (Score:2)
"Luke Raised his Macroculars to the sky and watched the Rebel ship be destroyed by the Imperial Star Destroyer"
To me this sounds suspicously like a Oil Filled Variable Focus Lens with higher magnification and image stabilization.
The big question though is this something new?
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The big question though is this something new?
Well, besides not being fictional, the big idea is that the thing (potentially) has a negative index of refraction, something not even the fictional lenses do.
Negative refraction is useful in making invisibility shields, by directing light completely around object surrounded by it.
This doesn't go nearly that far; it's a step towards a new way of constructing metamaterials with negative indexes. That's important; the "invisibility" stuff is just press-release science because invisibility is far more interes
Invisibility? (Score:5, Funny)
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An internal power source must obey the laws of thermodynamics and thus would cause the craft as a whole to be an infrared emitter. We are very good at detecting infrared light which would defeat most cloaking devices including this one.
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An internal power source must obey the laws of thermodynamics and thus would cause the craft as a whole to be an infrared emitter.
Now you're just being silly.
As IR is still light, put a second cloak inside the first cloak, but this time FACING the satellite, so the satellite can't see the earth either.
Now - that surely sounds like fractured logic - until you add a third cloak so the earth can't see that the satellite's not seeing the earth.
Wait - can you tell it's beer-thirty on Friday???
It WOULD work IF (Do that and you'll go BLIND) (Score:5, Interesting)
It would work "optically" if the Invisibility Cloak was made out of vegetable oil and you were made of Pyrex...
Vegetable oil and Pyrex has the same refractive index...
* put a small Pyrex jar into a larger one and then fill the smaller (inner) jar with vegetable oil and once it's full continue to fill the larger one with the overflow. The smaller (inner) jar will become invisible, to the naked eye.
On a more serious note this seems to be a big problem with all invisibility cloaks, of non supernatural origin (calm down HP fans), and that is they are all based upon modifying materials refractive index and thus bending the light around the object you want to hide.
That all sounds good but if you could do this to hide an object; If that object were a person since light doesn't hit them, or their eyes, not only would they be invisible but they would also be blind. I think most people asking Santa for a invisibility cloak would like to actually see what's in the girls locker room right?
A perfect invisibility cloak would change the person wearing it, along with the cloak, to a refractive index of air but again, they would be perfectly blinded by the process. In the case of RI = air then the light would go straight through them, included their eyes. So you either bend the light or have it go through your eyes and either way your in the dark.
I guess you could hide everything but your pupils, but in my book you wouldn't be invisible then, floating eyeball freak!
LOL
Nick Powers
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And this is exactly why a proper invisibility cloak must be computer controlled with millions of dots of resolution interspersed with millions of cameras. The idea is that, like a chameleon, you change to look like your background. With you inside, the cameras can also give you a view of your surroundings.
And yes, it would still give off a heat signature, but most people aren't walking around with night vision goggles all the time.
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An invisibility cloak, as in the sort used by harry potter, is not possible with a passive device. This is fairly obvious since you can't see light and yet be transparent to it at the same time.
However, there is no theoretical limit if the device is active. A simple example would be a flat panel display with a camera on the back. If you track the position of the observer, you can create a very convincing "invisibility" effect.
More interestingly, it may one day be possible to use active metamaterials to prod
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Google up "pinhole camera" or "camera obscura" and you will see that we've had the technology to solve that part of the problem for close to a thousand years.
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Why mod this funny? It's insightful!
Granted, as soon as you poke a camera out of the field it isn't 100% invisible, it's only 99.99% (or more) invisible. Still that's pretty damn good, do you know how hard it would be to notice a tiny dot floating around in space?
Battle of New Orleans (Score:2)
If you just fire yer musket at the pupils of their eyes"
"Makers of first invisibility cloak sued... (Score:1)
by the joint companies Scholastic Books and Warner Brothers Films due to copyright infringement over the J.K. Rowling works Harry Potter."
lasers (Score:2, Interesting)
chinese stealth armour? (Score:2)
or just a stealth boy?
Vaporware? (Score:2)