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 A real cloak of invisibility?
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HalfMooner
Dingaling

Philippines
15831 Posts

Posted - 05/25/2006 :  13:25:44  Show Profile Send HalfMooner a Private Message
This one's from an AP article at LiveScience:
quote:
Scientists Aim to Duplicate Harry Potter's Invisibility Cloak
By Andrew Bridges
Associated Press
posted: 25 May 2006
02:28 pm ET

WASHINGTON (AP)—Imagine an invisibility cloak that works just like the one Harry Potter inherited from his father.

Researchers in England and the United States think they know how to do that. They are laying out the blueprint and calling for help in developing the exotic materials needed to build a cloak

The keys are special manmade materials, unlike any in nature or the Hogwarts School of Witchcraft and Wizardry. These materials are intended to steer light and other forms of electromagnetic radiation around an object, rendering it as invisible as something tucked into a hole in space.

"Is it science fiction? Well, it's theory and that already is not science fiction. It's theoretically possible to do all these Harry Potter things, but what's standing in the way is our engineering capabilities,'' said John Pendry, a physicist at the Imperial College London.

Details of the study, which Pendry co-wrote, appear in Thursday's online edition of the journal Science.

Scientists not involved in the work said it presents a solid case for making invisibility an attainable goal.

"This is very interesting science and a very interesting idea and it is supported on a great mathematical and physical basis,'' said Nader Engheta, a professor of electrical and systems engineering at the University of Pennsylvania. Engheta has done his own work on invisibility using novel materials called metamaterials.

Pendry and his co-authors also propose using metamaterials because they can be tuned to bend electromagnetic radiation—radio waves and visible light, for example—in any direction.

A cloak made of those materials, with a structure designed down to the submicroscopic scale, would neither reflect light nor cast a shadow.

Instead, like a river streaming around a smooth boulder, light and all other forms of electromagnetic radiation would strike the cloak and simply flow around it, continuing on as if it never bumped up against an obstacle. That would give an onlooker the apparent ability to peer right through the cloak, with everything tucked inside concealed from view.

"Yes, you could actually make someone invisible as long as someone wears a cloak made of this material,'' said Patanjali Parimi, a Northeastern University physicist and design engineer at Chelton Microwave Corp. in Bolton, Mass. Parimi was not involved in the research.

Such a cloak does not exist, but early versions that could mask microwaves and other forms of electromagnetic radiation could be as close as 18 months away, Pendry said. He said the study was "an invitation to come and play with these new ideas.''

"We will have a cloak after not too long,'' he said.

. . .
Your comments?


Biology is just physics that has begun to smell bad.” —HalfMooner
Here's a link to Moonscape News, and one to its Archive.

Dude
SFN Die Hard

USA
6891 Posts

Posted - 05/25/2006 :  15:13:55   [Permalink]  Show Profile Send Dude a Private Message
The military applications alone of such a material....

Pretty freakin cool, imo.

Stealth to an entirely new level.


Ignorance is preferable to error; and he is less remote from the truth who believes nothing, than he who believes what is wrong.
-- Thomas Jefferson

"god :: the last refuge of a man with no answers and no argument." - G. Carlin

Hope, n.
The handmaiden of desperation; the opiate of despair; the illegible signpost on the road to perdition. ~~ da filth
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marfknox
SFN Die Hard

USA
3739 Posts

Posted - 05/25/2006 :  15:49:57   [Permalink]  Show Profile  Visit marfknox's Homepage  Send marfknox an AOL message Send marfknox a Private Message
Dude's right about the military possibilities. Not only that, but when we think about our right to privacy... eesh.

This American Life did an episode called "Superpowers" (read about and listen to here: http://www.thislife.org/pages/descriptions/01/178.html)
quote:
Act One. Invisible Man vs. Hawkman. John Hodgman conducts an informal survey in which he asks the age old question: which is better? The power of flight, or the power of invisibility? He finds that how you answer tells a lot about what kind of person you are. And also, no matter which power people choose, they never use it to fight crime. (13 minutes)
In this act the guy really analyzes the psychological stages that people go through when they decide on which power they want: invisibility or flight. The perverse and insecure nature of invisibility is discussed at length. It's a great show for anyone who has the time to listen to it.

Anyway, I'm no luddite, so bring on the Harry Potter cloaks. But let's also be cautious about it because whole new social norms and laws will be developed as such technology is integrated into society.

"Too much certainty and clarity could lead to cruel intolerance" -Karen Armstrong

Check out my art store: http://www.marfknox.etsy.com

Edited by - marfknox on 05/25/2006 15:51:25
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JohnOAS
SFN Regular

Australia
800 Posts

Posted - 05/25/2006 :  17:19:01   [Permalink]  Show Profile  Visit JohnOAS's Homepage Send JohnOAS a Private Message
Very interesting. I think a wearable "invisibility cloak" as seen in movies is still a long way off.

If you look into the research you'll see there are two approaches, one, in the article HalfMooner first linked to, involved bending light around an object. The second approach is to eliminate light scattered from an object. This second approach is much simpler, but doesn't result in true invisibility, just "blackness", which could be pretty spooky though. (Are those incoming silhouettes smiling in a friendly or evil fashion?) This approach is also perfect for cloaking where shadow detection isn't possible or easily done, such as most conventional aircraft detecting radar.

For the first approach to work, you have to be able to bend light incident on your object from all angles, and make sure it continues on it's way in exactly the same direction on the other side of the object. This is extremely difficult. A more readily achievable approach is to record the incoming light from one side, and re-transmit it by some means on the other. In a really basic implementation, imaging sandwiching yourself between a couple of parallel LCD/Plasma screens with a camera facing in each direction. The image recorded by the front camera is displayed on the rear screen, and vice versa. You can only make this scenario work well for a single optical axis, but for some applications that is good enough. (Mostly medium to long range, with a relatively small field of view.)

Many years ago I worked for an EOCCM (Electro Optic Counter Counter Measures) research group. (Even then I'm told there were guys working on aircraft systems that were 4-C, namely counter-counter-counter-counter measures). These sorts of things are obviously of major interest to armed forces, law enforcement and intelligence organisations.

Naturally, I want one.

John's just this guy, you know.
Edited by - JohnOAS on 05/25/2006 17:43:41
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Randy
SFN Regular

USA
1990 Posts

Posted - 05/25/2006 :  17:25:40   [Permalink]  Show Profile Send Randy a Private Message
http://news.bbc.co.uk/2/2777111.stm

Thought I recalled an attempt or pseudo attempt of a cloaking device. Googled "Japanese, cloaking" and found the above link.

"We are all connected; to each other biologically, to the earth chemically, to the rest of the universe atomically."

"So you're made of detritus [from exploded stars]. Get over it. Or better yet, celebrate it. After all, what nobler thought can one cherish than that the universe lives within us all?"
-Neil DeGrasse Tyson
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ktesibios
SFN Regular

USA
505 Posts

Posted - 05/25/2006 :  17:31:09   [Permalink]  Show Profile Send ktesibios a Private Message
Wjhy don't they just paint it pink and set up a Somebody Else's Problem field on it?

"The Republican agenda is to turn the United States into a third-world shithole." -P.Z.Myers
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H. Humbert
SFN Die Hard

USA
4574 Posts

Posted - 05/25/2006 :  17:42:38   [Permalink]  Show Profile Send H. Humbert a Private Message
quote:
Originally posted by JohnOAS
A more readily achievable approach is to record the incoming light from one side, and re-transmit it by some means on the other. IN really basic implementation, imaging sandwiching yourself between a couple of parallel LCD/Plasma screens with a camera facing in each direction. The image recorded by the front camera is displayed on the read screen, and vice versa. You can only make this scenario work well for a single optical axis, but for some applications that is good enough. (Mostly medium to long range, with a relatively small field of view.)
That's essentially what was done in the article Randy linked to. When I first saw the photos of a translucent man I thought, "that's amazing!" Then they explained that if the subject turned a few inches to either side the effect would disappear. Sort of a let down to realize it was so limited, but still very cool nonetheless.


"A man is his own easiest dupe, for what he wishes to be true he generally believes to be true." --Demosthenes

"The first principle is that you must not fool yourself - and you are the easiest person to fool." --Richard P. Feynman

"Face facts with dignity." --found inside a fortune cookie
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JohnOAS
SFN Regular

Australia
800 Posts

Posted - 05/25/2006 :  17:50:00   [Permalink]  Show Profile  Visit JohnOAS's Homepage Send JohnOAS a Private Message
Slightly off-topic, but not entirely...

One of the coolest demo's I remember seeing when working at defence was relatively low tech. We were shown an outdoor still shot, and told to pick the helicopter out. The scene showed a moderately forested foreground with a range of rocks of various sizes and the sky above the horizon for about a third of the frame.

For the life of me I couldn't spot the chopper. The frame was switched to the version without the camouflage net they were trialling, showing that the chopper took up about 25% of the horizontal frame. When switched back to the earlier frame again, you could of course recognise some features, but it was still damn hard to spot.

All of this was the result of some very good colour matching and materials research and all the regular outline breakup analysis that goes with conventional camouflage technologies.

John's just this guy, you know.
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Randy
SFN Regular

USA
1990 Posts

Posted - 05/25/2006 :  18:20:43   [Permalink]  Show Profile Send Randy a Private Message
http://projects.star.t.u-tokyo.ac.jp/projects/MEDIA/xv/oc.html

The power of brain scratching and Google...

"We are all connected; to each other biologically, to the earth chemically, to the rest of the universe atomically."

"So you're made of detritus [from exploded stars]. Get over it. Or better yet, celebrate it. After all, what nobler thought can one cherish than that the universe lives within us all?"
-Neil DeGrasse Tyson
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Paulos23
Skeptic Friend

USA
446 Posts

Posted - 05/25/2006 :  21:39:41   [Permalink]  Show Profile  Visit Paulos23's Homepage Send Paulos23 a Private Message
quote:
Originally posted by ktesibios

Wjhy don't they just paint it pink and set up a Somebody Else's Problem field on it?



Some adventure always comes by and turns the field off....

You can go wrong by being too skeptical as readily as by being too trusting. -- Robert A. Heinlein

Facts do not cease to exist because they are ignored. -- Aldous Huxley
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Dude
SFN Die Hard

USA
6891 Posts

Posted - 05/25/2006 :  23:12:48   [Permalink]  Show Profile Send Dude a Private Message
Visible wavelengths of light are very short, nanometers.

Radar, on the other hand, is in the milimeter range. A much less difficult technical challenge than bending the visible wavelengths.

The possibility of planes and warships simply invisible to radar is pretty cool.

The article suggests that such an application could be in use in as little as 18 months from now.

And, you know, once a team of really determined and smart dudes(gender neutral usage) get their teeth into something like this, with proof of the concept already in hand, it is only a matter of time before it becomes reality.


Ignorance is preferable to error; and he is less remote from the truth who believes nothing, than he who believes what is wrong.
-- Thomas Jefferson

"god :: the last refuge of a man with no answers and no argument." - G. Carlin

Hope, n.
The handmaiden of desperation; the opiate of despair; the illegible signpost on the road to perdition. ~~ da filth
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Ghost_Skeptic
SFN Regular

Canada
510 Posts

Posted - 05/25/2006 :  23:56:43   [Permalink]  Show Profile Send Ghost_Skeptic a Private Message
I wonder if echolocation (sonar) would work against this invisibility cloak?

At close range Filthy could always detect a cloaked individual by spitting tobacco juice at them.

"You can lead a horse to water but you can't make him drink. / You can send a kid to college but you can't make him think." - B.B. King

History is made by stupid people - The Arrogant Worms

"The greater the ignorance the greater the dogmatism." - William Osler

"Religion is the natural home of the psychopath" - Pat Condell

"The day will come when the mystical generation of Jesus, by the supreme being as his father in the womb of a virgin, will be classed with the fable of the generation of Minerva in the brain of Jupiter" - Thomas Jefferson
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woolytoad
Skeptic Friend

313 Posts

Posted - 05/26/2006 :  00:04:27   [Permalink]  Show Profile Send woolytoad a Private Message
Sonar will still work. We're just bending light here.

WE would have to use more conventional stealth methods (F-117) to neutralise sonar.
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