Slashdot Mirror
Engineers Devise Invisibility Shield
GerritHoll points out an article in Nature according to which "researchers at the University of Pennsylvania 'say that a "plasmonic cover" could render objects "nearly invisible to an observer.' Earlier attempts at invisibility worked by colouring a screen to match its background, like a chameleon. The described technique is new, because it works by the concept of reducing light scattering. It is not a 'magic cloak,' however, because it will not work for the full range of visible light and needs to be adjusted precisely for the shape of the object. However, the concept could find an application in stealth technology."
It is not a 'magic cloak,' however.
Like this?
Well, that actually requires a special viewfinder, so it's not quite as cool, but it sure *looks* awesome. Better than the "spot the spaceship" pic, anyway.
How long til I can buy this stuff at Walmart?
What sort of armor class do you get with that?
Making something invisible is easy: all you have to do is generate a Somebody Else's Problem field of sufficient size.
(Seriously, am I the only one who looked at this, saw the word 'plasmonic', and thought "Fucking Slashdot editors, its *March 1st*, not *April 1st*"?)
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Mod me down, you fucking twits. Go ahead. I dare you.
(I read with sigs off.)
I didn't see that one coming.
This technology would only work for microscopic objects (as they must be the same size as the wavelength of light hitting it), and only a single wavelength. So in other words, for you to get a nice, new cloak of invisibility you'll need to be microscopic in size and constantly in environments with only one wavelength of visible light hitting you. =)
Well, back to the drawing board.
-Vendal Thornheart
... to let me sneak undetected into a ladies locker room, then we'll talk.
bash: rtfm: command not found
the whole basis of this is to stop the scattering of light that the object emits. so if there was no scattering, then wouldnt the object still appear black. sooo. couldnt you just look for the object that's all black. might work well in space or night time, but at 2pm on a sunny afternoon, i think i'll be able to spot the large black body trying to hide.
See, it hides my identity when I post on Slashdot!
...obstracle.
Obstracle = obstruction + obstacle?
I can think of a couple of obvious applications, especially if the technology can be adapted to scatter microwaves. Tanks and mechanized infantry are pretty obvious, but I think we want to avoid battleships unless we want a repeat of the Philadelpha Experiment and the crappy movie versions (though I loved the first one as a kid).
But what about non-military uses? Perhaps a "coat" of plasma on windows to reduce cooling bills in the summer? Or another coat of plasma on TV's to reduce glare? I can't think of anything particularly inspiring.
After all, I am strangely colored.
This is awesome. Can I use this on my mother?
My Linux - (L)ove (I)s (N)ever (U)tterly eXPensive
The object being hidden has to be less than the about the wavelength of the light. So, unless you are nanometers in size, you won't be hidden from visible light.
And it only works on one frequency. Meaning, unless you are nanometers in size, and you are in a room with only red light, you won't be hidden.
This isn't that great. I wouldn't read too much into it.
The radical sect of Islam would either see you dead or "reverted" to Islam.
From the article: "And crucially, the effect only works when the wavelength of the light being scattered is roughly the same size as the object. So shielding from visible light would be possible only for microscopic objects."
OK. So if I have this straight... "You see that thing you can't see because it's too small? Well we just made it invisible! Please send more grant funding. And a few burritos. We're like, totally hungry dude."
Uh huh....
Here is the technique let yourself invisible, try it yourself: http://www.sciforums.com/showthread.php?p=439508
From the article:
...it would be more like the shielding used by the Romulans in the Star Trek episode "Balance of Terror" in 1966, which hid their spaceships at the push of a button.
...it's called a "cloaking device", you insensitive clod!
Really? Invisibility could be used for tasks requiring stealth? No way, that's crazy talk.
What if this concept works for other EM waves, like radar, for instance? I don't remember the precise wavelength of most radar waves, but they are rather long (I'm thinking meters). Could an object smaller than the wavelength of a certain radar be stealthed by this "invisibility" shield?
This article is like going to a movie after seeing the really great preview, and finding out that the really great preview contains every single really great moment in the movie.
U.S. Air Force scientists looked into generating a field of plasma around an aircraft to reduce aerodynamic drag. One unexpected effect was a reduction of RCS (radar cross section, a rough measure of radar visibility), though to my knowledge the research has not been pursued (it probably continues in classified state, just like the plasma toroid ABM system 7 years ago...). Of course, this is EM radiation in the radio portin of the specturm, not optical.
Russian electrodynamicists are also infamously known for proposing "plasma stealth" devices, which have yet to be demonstrated veritably well. Every few months something pops up about how they've solved high power requirements, reduced weight of the devices, eliminated interferce with the aircraft's EM devices (radar and comm/nav, which critical to everything) and problem Y. And then, you see nothing of it in any journal or trade publication. Just claims, and it seems, nothing more.
Notably, plasma radar stealth has an opposite effect of the optical stealth. The aircraft would glow like a lightbulb, and leave a trail of glowing plasma in its wake. Also notably, aircraft at high hypersonic speeds induce a local plasma air environment, due to the tremendous energy of the aerodynamics.
It's made me invisible to women for 10 years now.
I wish I could turn it off.
You probably don't remember it because it doesn't exist. There are numerous radars using everything from millimeter waves (MMW) to multi meter long waves. Each type has its own specific uses, though I've heard that MMW radar is the most difficult technology to develop. But IANAEE (electrical engineer).
Here's an obligatory link to the pre-print research paper and the abstract:
http://arxiv.org/abs/cond-mat/0502336
Achieving transparency with plasmonic coatings
Andrea Alu, Nader Engheta
The possibility of using plasmonic covers to drastically reduce the total scattering cross section of spherical and cylindrical objects is discussed. While it is intuitively expected that increasing the physical size of an object may lead to an increase in its overall scattering cross section, here we see how a proper design of these lossless metamaterial covers near their plasma resonance may induce a dramatic drop in the scattering cross section, making the object nearly invisible to an observer, a phenomenon with obvious applications for low observability and non invasive probe design. Physical insights into this phenomenon and some numerical results are provided.
The article puts two techniques next to eachother, as if it were alternatives for the same problem. This is false.
The proposed system with plasmonic covering reduces the scattering of light. The lightwaves pass by the object as were the object very small, smaller than it actually is. Hence it only works with objects that are allready very small, because otherwise the object would cast a shadow. (Light passes by, not through)
The system with light detectors and emitters mimics the scene that is behind (bigger) objects with respect to the viewer. You could actualy say that it fills in the shadow cast by the object.
So were the first system reduces the shadow effect, the second replaces the shadow alltogether. I could actualy see these two systems used along side eachother rather than instead of eachother.
"And crucially, the effect only works when the wavelength of the light being scattered is roughly the same size as the object."
Visible light is around 400nm (violet) to 800nm (red). So, this is only effective for sufficiently tiny battleships.
I'm about five-eight, and deep-seated insecurity seems to hide me from most things. Does anyone else have similar experiences?
Stealth and camouflage!
Dear horsebutt,
You have used the phrase "copying movies" in your Slashdot post #11810495, dated March 1st. We remind you that copying movies is a dangerous and illegal activity, which can have harmful effects ranging from misguided threats of legal action from MPAA legalbots to being made to sit through Gigli. Think of all the millions of Hollywood actors living on the streets and eating out of dumpsters because of your thoughtless, violent and evil crime.
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RIAA LegalBot[tm] #1024 "Jeff"
I won't believe this 'til I see it.
Move along...
This comment does not necessarily represent the views and opinions of the author.
the rubber-glue matrix. What use is an invisibility shield without a robust name calling defense system.
So in other words, for you to get a nice, new cloak of invisibility you'll need to be microscopic in size
Not a problem. If you'll just step right over here to this shrinkometer....
Tweet, tweet.
the effect only works when the wavelength of the light being scattered is roughly the same size as the object
This would make it the perfect for those awkward moments when your nanobots are being attacked by lasers (mounted on sharks?)
The world has changed and we all have become metal men.
Now we can penetrate those pesky secure quantum communication links without a man in the middle attack! Simply by stealthifying the particles use use to determine the state of the information carrying particle.The information carier is unaware that it is being observed and its quantum packet doesn't collapse. Woot! Send me my nobel prize asap!
They whose government reduces their essential liberties for temporary security, receive neither liberty nor security.
I have thought about this few times(when feverish or some other way mentally challenged states) and decided that our technology isn't yet suitable to accomplish this.
Basically it's quite simpple - all you have to do is route every incoming photon around the object without changing it's course.
Fabric made of nano-fibres?
/* If everybody would be like me the world would be much better place to be - at least in my mind. */
The Japanese "invisibility cloak" is nothing more than the front projection technique used in 2001: A SPACE ODYSSEY and many other films. That's like claiming that we have a super weapon that can hit an enemy anywhere -- provided he stands right here on this spot marked X. The alleged surgical and pilotting applications sound equally silly. It is an infinite regression of "if we can fit a camera in front of the surgeon's hands, we can project an image behind them to make a really cool effect that they are invisible!"
I don't think these engineers devised any sort of "invisibility shield"
...match its background, like a chameleon.
Grrr...
Chameleons don't change their colors for this reason. It's a myth. Stop spreading it.
http://www.wsu.edu/DrUniverse/chamel.html
// file: mice.h
#include "frickin_lasers.h"
Wonder Woman sued the University of Pennsylvania over Intellectual Property involving invisibility technology. No one on campus could be found for comment.
Why do engineers need to develop methods of invisibility? After all, most engineers are invisible to the female half of the population anyway.
If "disco" means "I learn" in Latin, does "discothèque" mean "I learn technology"?
This technology is really invisibility in the sense that it stops light scattering, but for visible light would only work for microscopic items...
Which must be working because right now I so not see many single microscopic items anyway...
It can't be used to conceal guns from Xrays, which use 0.1nm-20nm wavelegths.
Hiding missiles from radio based radar? Possible?
So shielding from visible light would be possible only for microscopic objects; larger ones could be hidden only to long-wavelength radiation such as microwaves. This means that the technology could not be used to hide people or vehicles from human vision.
Also the 'inventiveness' of the invisibility cloak is much less than its engineering feat.
We all have our own ideas about projecting the view behind your onto the front... from all angles... technically how to do it flexible, and stop illumination / shadow is very hard.
Not impossible, with some very clever technology that can 'feel' its own shape, and sense light conditions, can absorb almost all light (be dark even in bright light, if a shadow is behind you), and shine as bright as the sun on a rock (if you are in the shade, but a bright rock is behind you, and you cannot use the sun on the material to compensate)
This would require some l33t processing skills to handle the data.
#hostfile 0.0.0.0 primidi.com 0.0.0.0 www.primidi.com 0.0.0.0 radio.weblogs.com
The force that blew the Big Bang continues to accelerate.
It seems like they need to watch this again. (In searching for an appropriate link, I also stumbled upon a strange amalgamation of Monty Python and JRR Tolkein. It's bloody hilarious if you know both.)
Ben Hocking
Need a professional organizer?
My tin foil hat has been rendering me invisible for years. Right now I'm wearing it naked at work.
"Hi Bob, what are you looking at?"
All of this is meaningless until they discover how to create the Holocaust Cloak. What I wouldn't give for a Holocaust Cloak right about now.
"And of course the shielding would work fine for concealing large objects such as spaceships from sensors or telescopes that used long-wavelength radiation instead of visible light."
Now we know how advanced alien civilizations have remained "off the radar", despite our sweeping radar telescope surveys of their space abodes. They're not that much more advanced than us. But they've concentrated on the important bits: privacy technology. We'll neve catch up at this pace.
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make install -not war
I'm getting bored of the hype required to get any science/technology advances written up. It's not an invisibility cloak, you knew it before you wrote the article and I knew it before I read the article. Why does good science need to hide behind stupid banner headlines?
Also, (because I'm grumpy today), Chameleons do not change colour to blend with their background. FFS. See Wikipedia: Chameleon.
If only someone had invented a fusion reactor that ran on pure bullshit we'd all be rolling in it (so to speak).
And crucially, the effect only works when the wavelength of the light being scattered is roughly the same size as the object. So shielding from visible light would be possible only for microscopic objects...
Which are frikkin' microscopic and therefore don't need to be hidden?
Or is it just me that can't see microscopic objects?
IANAL, but I've seen actors play them on TV
Come on, guys! I can't be the first to notice... Okay, I'll spell it out for you -- the correct first reaction to this story is:
(Have none of you kids ever heard of The Philadelphia Experiment ?)
David Gould
main(i){putchar(340056100>>(i-1)*5&31|!!(i<6)<< 6)&&main(++i);}