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Comments: 219 +-   Scientists Make Item Invisible to Microwaves on Thursday October 19 2006, @12:49PM

Posted by Zonk on Thursday October 19 2006, @12:49PM
science
technology
Vicissidude writes "A team of American and British researchers has made a cloak of invisibility. In their experiment the scientists used microwaves to try and detect a copper cylinder. Like light and radar waves, microwaves bounce off objects making them visible and creating a shadow, though it has to be detected with instruments. If you can hide something from microwaves, you can hide it from radar and visible light. In effect the device, made of metamaterials — engineered mixtures of metal and circuit board materials, which could include ceramic, Teflon or fiber composite materials — channels the microwaves around the object being hidden. When water flows around a rock, co-author David R. Smith explained, the water recombines after it passes the rock and people looking at the water downstream would never know it had passed a rock. The first working cloak was in only two dimensions and did cast a small shadow, Smith acknowledged. The next step is to go for three dimensions and to eliminate any shadow."
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  • I know a recently-shampooed poodle (Score:5, Funny)

    by Anonymous Coward on Thursday October 19 2006, @12:51PM (#16504445)
    ...that would love to be invisible to microwaves.
  • The article mentions that doing the same thing to light waves should be possible.

    How long do you think till you can pick up a Cloak of Invisiblity at your local MegaMart?
    • This was already addressed to some degree in the SciFi book "The Last Mortal Man". The reasoning for making them illegal was that the criminal element used them to evade law enforcement. I'm sure the DHS would have alot to say about this.
      • Ok, on a serious note then:

        How long till we see military issue suits? They wouldn't have to be perfect to be a big help to infantry in medium cover terrain.

        Of course, almost anything military gets a civilian version eventually, so we're back where I started.

        • Re:Quite some time. (Score:5, Interesting)

          by Rei (128717) on Thursday October 19 2006, @01:27PM (#16505093) Homepage
          And the biggest beneficiary of infantry invisibility suits? Guerilla fighters.

          Sure, they won't get them right away. But you better believe that they'll try to capture them, and any state sponsors that they have immediately try and produce or otherwise acquire them. Big armies, trying to cloak things like tanks driving down the stret, will have a much harder job at it than fighters simply hiding themselves and their RPG, already in the shadows or buildings. Not to mention things like pressure or vibration-triggered mines/IEDs won't be affected, which also benefits guerilla fighters on their own turf.

          • Re:Quite some time. (Score:5, Insightful)

            by c6gunner (950153) on Thursday October 19 2006, @02:11PM (#16506007)
            It just means that organized combat would evolve to take advantage of them also. Ever since WW2 we've been moving to smaller and smaller units working as independent organizations, then re-combining to carry out more complex tasks. With the introduction of cloaking technology you'd see the extreme end of that. 4-8 man squads operating independently on foot and light vehicles, hunting down guerrillas the same way the currently hunt us. Biggest obstacle to us doing that NOW is that we're so easy to identify. If we could have small units operating all over a city, totally invisible to anyone...well, good luck trying to plant IED's, or even gathering at your buddy Ahmed's house to discuss tomorrow's plan of attack.

            • Re: (Score:3, Interesting)

              by iluvcapra (782887)
              The way you describe it, military cloaks of invisibility would seem to be plainly illegal under the Hague Conventions [yale.edu], supposing that killing an enemy while you are invisible translates as a "treacherous act," by Article 23. Also if you engaged in combat under a Cloak you would be necessarily trading in your protections under GC1 and 3.

              • Re: (Score:3, Informative)

                by c6gunner (950153)
                Nonsense. Well, the Hague convention art. 23 bit is nonsense anyway. You could argue that we already "kill treacherously" because we employ camouflage, snipers, artillery, landmines, etc. Any such argument would be just plain silly though. The treachery part of the Hague conventions refers more to things like poisoning, or getting your prostitutes to "distract" them while you sneak up and slit their throats (sound unlikely? think about how old these conventions are). As to the GC, you're absolutely ri

      • Re: (Score:3, Insightful)

        by toddbu (748790)
        The reasoning for making them illegal was that the criminal element used them to evade law enforcement.

        This assumes, of course, that the criminal element (or anyone else for that matter) will be able to use the cloaks successfully. Think about how hard it would be to rob a bank. If you're wearing the cloak then how does the teller know that you're there demanding money? Perhaps you just want to cloak the getaway car. How do you find it back when you're done with the job? Even if you remembered where

        • Re:Quite some time. (Score:4, Insightful)

          by Rei (128717) on Thursday October 19 2006, @01:39PM (#16505359) Homepage
          That's silly. The teller can hear you.

          Even if there was no "on-off" button on this, it would be trivially easy to "make" one. Paint water colors on all or part of the object that you can wash off. Tape on visible objects. Put a cover over it. Etc. This assumes that the cloak *itself* isn't flexible, allowing you to take that on or off.

          Also, I doubt it'll be perfect invisibility. Even if, to the naked eye it appears perfect, I doubt it would to custom goggles analyzing the scene. Surely there are some wavelengths that it won't work on (from the sound of it, you need to customize a layer of this for a *specific* wavelength). Or the polarity could be thrown off. Or all sorts of other things.

        • Re:Quite some time. (Score:5, Insightful)

          by XenoRyet (824514) on Thursday October 19 2006, @01:41PM (#16505413)
          The real issue, and the major downside to a cloak of this nature, is how do you see where you're going while you are wearing it?

          If it's diverting all the light around you, there's no light to get in and hit your eye so you can see.

          The solution would be much more complex than the basic cloak. You'd have to let some light in, but make sure it didn't get back out again. I can see that being problimatic.

          • Re: (Score:3, Interesting)

            by beyowulf (1014741)
            I suppose they'd have to make the cloak invisible to the visible spectrum and provide goggles to see the non-visible(Infared, UV) spectrum.

          • Re: (Score:3, Insightful)

            by gutnor (872759)
            You only need 2 little holes of 5 mm and you have all the lights needed for your eyes. Considering the likely imperfection of the invisibility suit, it is likely that when you can spot the holes, you are already close enough to detect the wearer.

            • But a moving object is still traceable, as it will physically disturb the environment around it. A human will trample vegetation, break branches, or leave footprints etc. A tank will leave track prints, stir up a whole lot of dust, and many other such things.

              So this technology would be most useful for hiding static vehicles/persons, or perhaps even moreso for hiding buildings (think, a whole, semi-invisible bunker).

              I wonder how it would affect sound waves as well. Perhaps sonar would pick up things that

          • Re:Quite some time. (Score:5, Funny)

            by borawjm (747876) on Thursday October 19 2006, @03:04PM (#16507091)
            The real issue, and the major downside to a cloak of this nature, is how do you see where you're going while you are wearing it?

            Use your feelings, you must

        • Re: (Score:3, Insightful)

          by CmdrGravy (645153)
          I'm sure any relatively non moronic criminal would quickly work out how to maximise the benefits of being totally invisible and avoid the risks you have mentioned. For example if you were invisible you wouldn't need to ask the teller anything, just follow someone into the secure area of the bank, hang around for a while seeing where all the keys etc are kept and then wander into the vault stuff as much cash as you can carry under your invisibility cloak and wander out again. I don't see why you'd need a get

    • Re:Why should Harry Potter have all the fun? (Score:5, Informative)

      by thermopile (571680) on Thursday October 19 2006, @01:24PM (#16505005)
      I was on a selection committee for DARPA to look into this stuff a few years ago.

      Negative Index of refraction Materials (NIMs), metamaterials, or whatever you want to call them, are relatively easy to make in the microwave region, since the wavelengths are on the order of centimeters. Thus, using a special arrangement of rings, loops, and wires, you can craft a lattice-like material that exhibits negative refraction. Technically, it has a negative magnetic permeability (mu) and negative permittivity (epsilon).

      This has all kinds of weird implications. The group velocity is still in the forward direction, but the phase velocity goes in reverse. Evanescent waves propogate, not die off. Perfect lenses can be made. Measurements LESS than the wavelength of light can be taken. There was a list of implications in the August issue of Scientific American, I believe.

      Anyhow, this works great at the ~cm scale. Visible light is hard as hell: the scale there is on the order of nanometers. And the copper or silver or tungsten wires used to make the metamaterials have MISERABLE magnetic losses at these small scales, so mu is no longer negative. The energy no longer propagates in the medium. As of three years ago, there were no promising candidates for solving this problem. There was an outside hack at using carbon nanotubes -- which may or may not maintain their permeability down to small scales -- but it was a long shot at best. Arranging the little guys would have been devilishly difficult.

      Glad to see that Pendry, who's been in this field almost as long as Veselago, is still making good strides. Even if they can't get to the visible wavelength, NIM's have spectacular applications for microwave antennae.

    • But when you walk to the aisle with all of the cloaks how will you find them

    • How long do you think till you can pick up a Cloak of Invisiblity at your local MegaMart?

      Maybe you can already, but I've never seen one myself.

  • hmm, (Score:4, Funny)

    by joe 155 (937621) on Thursday October 19 2006, @12:53PM (#16504473) Journal
    I'm unsure about the water claim, although it is true that you can't tell the difference that doesn't mean that it's not different, the water has been moved all over the shop, but it looks like it hasn't been affected.

    Other than that if they make something invisable from visable light then it wouldn't be able to see anything, so a person would be blind or a bot would be virtually impossible to navigate, because you couldn't see it or track it...

    Still, very interesting idea.

      • Re: (Score:3, Insightful)

        by Daniel_Staal (609844)
        I'd say the simplest is just to make a few small holes in the cloak. If they are small enough they will be overlooked. Attach a small camera to the hole, and you've got a good chance of a wide field of view with a dust-mote sized hole.
      • Just think of the military uses. All you have to do is convince your enemy to use this on the roof of all their sensitive laboratories.

  • Moo (Score:4, Insightful)

    by Chacham (981) on Thursday October 19 2006, @12:54PM (#16504489) Homepage Journal
    FTA:
    A team of American and British researchers has made a Cloak of Invisibility. Well, OK, it's not perfect. Yet. But it's a start, and it did a pretty good job of hiding a copper cylinder.
    So, we'll just just change his name to Harry Copper.

    This title is absurd. Invisibilty?

    The research is very kewl though, and i hope it progresses. But why not lay off the stupid titles, and produce results based on kewlness or usefulness, instead of what can be termed with a popular buzzword. Information Technology is bad enough from its buzzword infusion. Must we destroy legitamte research/discoveries as well?

  • Yay for TV Dinners (Score:5, Funny)

    by Odin_Tiger (585113) on Thursday October 19 2006, @12:54PM (#16504493) Journal
    This will allow for more variety in TV Dinner desserts, because they can just shield it so only the stuff that needs to get nuked will get nuked. w00t!

  • You know you are a fat geek when... (Score:4, Funny)

    by B5_geek (638928) on Thursday October 19 2006, @12:54PM (#16504499)
    You know you are a fat geek when...
        the first thing that came to your mind when reading this summary was:

    "Oh cool, no more burnt and undercooked mini-pizzas!"

    I really should go outside more often.

  • Bah! (Score:5, Funny)

    by Clazzy (958719) on Thursday October 19 2006, @12:56PM (#16504539) Homepage
    They could've posted a pict...

    Oh, wait. Never mind!

  • TERRIBLE NEWS! (Score:3, Funny)

    by abscissa (136568) on Thursday October 19 2006, @12:58PM (#16504565)
    What!! This is awful!! It means my microwave item-detecting device, which I walk around with to detect objects and random items, will now be obsolete!!

  • meta-materials (Score:5, Informative)

    by lgw (121541) on Thursday October 19 2006, @01:02PM (#16504625) Journal
    If you can hide something from microwaves, you can hide it from radar and visible light.

    I don't think this follows, at least when we're talking about metamaterials [wikipedia.org]. So far no one has invented metamaterials for optical wavelengths, as metamaterials rely on complex structure that's somewhat wavelength specific. It's easier to play "fool the photon" with microwaves (because of the longer wavelength) or X-rays (because of the higher energy) than it is with visible light. (Xiang Zhang's experiments in extending near-field effects of visible light are a very different mechanism, and are lumpedin with metamaterials simply for lack of a better term.)

  • Was Anyone Else Thinking... (Score:4, Funny)

    by Banner (17158) on Thursday October 19 2006, @01:02PM (#16504629) Journal
    Romulan Bird of Prey? (Or equally, the small Klingon ships also armed with the cloaking device?).

    Sorry, grew up on waaaay too much startrek :-)

    • Re:Was Anyone Else Thinking... (Score:4, Insightful)

      by angelasmark (856143) on Thursday October 19 2006, @01:16PM (#16504869) Journal
      You obviously didn't grow up on too much star trek. Any true trekkie would know that its a Romulan Warbird and a Klingon Bird of Prey...

      • Re:Was Anyone Else Thinking... (Score:5, Funny)

        by OfficialReverendStev (988479) on Thursday October 19 2006, @02:01PM (#16505813)
        You obviously didn't either. Somebody bring me the learnin' stick. You're both technically right. The Romulan Bird-of-Prey (from TOS, small white-ish ship with the bird painted on the bottom) did have a cloaking device, as did the Klingon (and Romulan) D-7 Battlecruiser. In the TNG era the Romulan Warbird (big and green) and the contemporary Klingon ships (Bird-of-Prey and Vor'Cha). Now, go play. I have a phaser to polish.
  • Apparently, he had an accident with the targetting mechanism.

  • Backpack of Invisibility? (Score:5, Interesting)

    by Doc Ruby (173196) on Thursday October 19 2006, @01:12PM (#16504791) Homepage Journal
    I'll go out on a limb on a series of "ifs" (and maybe a bag of physics naivetes), but let's say we perfect this manner of imperceptibly "derefracting" light. And let's say we also complete the ambitious work identifying and manipulating gravitons, still hypothetical. Could we "cloak" spaces and matter from any interaction with our universe, not just electromagnetic? Maybe the Stong and Weak Forces would remain for interaction, but practically, outside the tiny diameter of a nucleus, could anyone notice?

    Could a "gravity cloak" create subspaces operating as independent universes? Could we contain matter too highly interactive for current use safely? Like a tiny black hole conveniently near a device it's powering, or a pair coupled into a wormhole for "faster than light" travel through custom-folded space? Vast amounts of stuff crammed into pocketsized spaces.

    Maybe the old playground philosphers choosing between "teleportation or invisibility superpowers" will finally have a lab to figure out which is really better.
    • Could we "cloak" spaces and matter from any interaction with our universe, not just electromagnetic?

      It's already been done. But you don't even have to cloak gravitons. What do you think all that dark matter is? It's intersolar sprawl, and the aliens use the cloaking so that we don't keep bothering them, asking for technology.

  • Stealth Ship (Score:5, Insightful)

    by rlp (11898) on Thursday October 19 2006, @01:13PM (#16504815)
    Sounds like a better version of stealth. I recall reading that an early attempt at a stealth ship did TOO good of a job of dispersing microwaves (compared to background reflection of empty ocean) and showed up as a moving 'hole' on surface radar screens. Assuming that this technology could be applied to bending light around an object, it would need to do so without creating obvious distortions.

  • I have a cheaper way to do this (Score:3, Funny)

    by WillAffleckUW (858324) on Thursday October 19 2006, @01:18PM (#16504901) Homepage Journal
    I make myself invisible to microwaves by unplugging them, or turning off the lights.

    Sneaky little buggers, always watching you and beeping at you to take your dinner or coffee out ...
  • Without debating the practical aspects of invisibility, I do have to wonder if this could be useful as some sort of radiation shielding? If they're able to do it for more energetic forms of e/m than microwave radiation, it seems to me that it would make an excellent shield. It doesn't have to be perfect invisibility, allowing me to "peek out" of the shield is fine. It doesn't even have to be non-detectable - I don't mind a visible "energy distortion" or "energy turbulence" or whatever - I just don't want to get fried.

    Yes, I know - this won't do that much against baryonic radiation, but for e/m . . .

  • Just paint the copper cylinder pink and turn on a cheap and simple Somebody Else's Problem Field.......

    • Re: (Score:3, Insightful)

      by UbuntuDupe (970646)
      True, but to dismiss something like this because it's still possible to detect the cloaked object would be in error. Think about the camoflauge gear militaries already use. You can still see them. HOWEVER, if you're not looking carefully enough, it's a lot easier to miss them in certain environments. The point of cloaking or camoflauge is not to make you undetectable, but to make it require more resources to detect you, just like the point of encryption is not to make the data unreadable to others but to

    • Re:Actual invisibility is useless (Score:5, Insightful)

      by DrKyle (818035) on Thursday October 19 2006, @01:47PM (#16505527)
      There's this thing called a pinhole camera, it's a relatively new advance. By allowing this pinhole of light in with the proper equipment just enough light could be absorbed to allow the user to navigate. Of course there would be a visible pinhole floating in space, but could you reliably pick it out at a distance of more than a few feet?
      • There's this thing called a pinhole camera, it's a relatively new advance.

        And, folks, here's a case indicating the limits of moderation by the unwashed masses. A pinhole camera [wikipedia.org] is the very oldest type of camera. Having no lens, it can be made with a box and (gasp!) a nail. It is known to have been known about by the Chinese somewhere in the 5th century B.C, and Aristotle in 4th century B.C. [photo.net] Oh, how a small bit of research in widely available knowledge could have saved the parent poster from looking like
        • There's this thing called sarcasm, it's a relatively new advance. By stating a clearly false proposition in the proper tone of voice a touch of humour can be added while still conveying to the reader the intended meaning. Of course on the Internet the tone of voice can be lost, but what sort of moron would fail to realise this?
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