Cloak of Invisibility Coming Soon

davaguco writes "It seems that we will finally be able to make ourselves invisible" It seems like this story resurfaces every few months and then gets submitted a zillion times so here it is. Personally I'm still waiting for my cloak of evasion. 20% miss chance is awesome.

Re:Wouldn't it be easier...

[Vengeance]

Judging by the American news media, I'd say it's already been invented and is in active use.

Re:Wouldn't...

[kimvette]

No, but a mosaic of microscopic convex mirrors might. The effect is such that you get the kind of "invisibility" that a chameleon does; the material would refract (or in the case of mirrors reflect) a blending of colours from surrounding objects, such that when an object is motionless it becomes very hard to pick out from the background due to the lack of contrast. It might be similar in appearance to the "invisibility" you see in the Predator movies. Not 100% invisible, but more of a shimmering, blended-in look, only it would not be transparent. If an object were to move behind the camoflauged object, you would immediately be able to pick it out from the background and target it. That's my guess, anyhow.

A single mirror wouldn't cut it - if a flat mirror, you'd see a singular object from elsewhere in the region, or if a convex mirror, you'd see yourself in the mirror, along with your background. It would stand right out from the background, like an AC troll in an otherwise-reasonable discussion. ;)

Re:Apparently not quite reality yet

[BaronHethorSamedi]

Ah, but try proving the non-existence of an invisible device...

Re:Slashdotters already have that power

[houstonbofh]

Motorcyclists have had this power far longer that slashdot AC's.

erm... are they sure they have the physics right

[moochfish]

Prof Milton's team calculated that when certain objects are placed next to superlenses, the light bouncing off them is essentially erased by light reflecting off the superlens, making the object invisible.

Wouldn't that make the cloak appear like a big black void of light?? Making things "invisible" requires light from the objects behind the cloak to pass through it.

Re:Pictures

[servognome]

This Is What Scientists Actually Believe!

Science isn't about the "truth," it is about models that explain a set of data. Doesn't matter if their model is real, it explains and predicts a set of behavior. Once data is discovered that contradicts the model, scientists work on reformulating it.

Y'know, just tell me when this stuff is here.

[Anonymous Coward]

Flying cars, inviso-fabric, moonbases, robo-wives... all sound great but just let me know when this stuff has actualized rather than telling me "it's on the way". Otherwise I'll have to start rooting around 20-30 year old issues of Popular Mechanics finding the exact same stories over and over and post them as "well, if it was just around the corner in 1976 it's sure to be here by now!" stories.

Painting something black doesn't make it invisible

[dpbsmith]

All of these "cloaking" stories suffer from basically the same problem. Making something invisible is much, much more complicated than blocking light, or cancelling light, or anything like that.

The article says, rather imprecisely, "when certain objects are placed next to superlenses, the light bouncing off them is essentially erased by light reflecting off the superlens, making the object invisible."

But "erasing" the light reflecting off an object doesn't make it invisible, any more than painting a car black... even matte black... makes it invisible.

In a dark room, if you cover a light with a black box it becomes invisible. When viewing a star from the earth, if it is occulted by, say, the moon passing between you and the object, it becomes invisible. If I pull a red cloak over myself, covering myself completely, you can no longer see me. You cannot tell who I am and if I stand very still perhaps you cannot tell that I am not a statue, so, in a sense, I have become invisible.

But, to become invisible in the sense of H. G. Wells' "The Invisible Man," or a Star Trek cloaking device, or James Bond's invisible car, or what have you, requires much more than "not being able to see" the object. It means not being able to detect the presence of the object... under real-world lighting conditions, with real-world scenes _behind_ the object, and from more than one vantage point at the same time.

That last one is the problem with many of these schemes. It doesn't do any good to make an object invisible when viewed by your right eye if there are "matte lines" around it when viewed with your left eye. It doesn't do a lot of good to make an object invisible as viewed from one soldier if it is visible to everyone else in the platoon.

Re:Invisible... or black?!??

[dhj]

That's exactly true for human vision and the requirements for true invisibility... However, radar isn't quite as sophisticated as human vision. Rendering an object black is essentially the same as rendering it invisible because radar systems detect the reflection of radar off of objects to determine their location. The radar is actively transmitted and I imagine it would be very difficult to determine the difference between lack of reflection from dissipation vs a lack of reflection from absorbance of an object. You're absolutely right about the visible light spectrum. They would be seen as black. Planes flying with complete radar absorbtion and at night would essentially be "invisible" until it was too late to respond. Night vision detection would be much less effective when a plane is seen only as a "lack of stars" in the area where the plane is absorbing light. There are definitely techniques which could be developed (and probably already have been) for detecting a "moving shadow" on a starlit (or reflecting cloud-lit) background.

--David

Re:Pictures

[JackCroww]

Just because you don't understand the science, doesn't make it invalid. You are not the final arbiter of all that is logical in the world.

All you do is broadcast your ignorance to the world. What really astounds me is how proud you are of your ignorance.

Re:Screw that!

[Alsee]

Screw the rocket roller skates. I want that neat black paint the Road Runner uses to paint tunnels onto mountainsides.

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