AMAZING PHOTO! scientists closer to creating invisibility cloak

[Flying Spaghetti Monster]

http://www.cnn.com/2008/TECH/science/08/11/invisibility.cloak.ap/index.html

WOW that photo really is amazing. And it's 5 years old. Who knows how close they are now.

 

[Lindley]

It must be working. I don't even see a picture on that page!

 

[msbae]

What photo? All I see is a short article.

 

[Mr. Adventure]

It's amazing, it blends right into the page.

 

[Uplink]

I just read an article that seems to be about the same story: http://nextbigfuture.com/

And it has what I think is the picture you are looking for above.

 

[MarianLH]

I wonder if they would've ever thought to try if Star Trek hadn't had the idea first. Does the idea of concealing something by bending light around it appear in SF lit prior to TOS?


Marian

 

[TerriO]

Well, the idea of invisibility in science fiction goes all the way back to H.G. Wells' The Invisible Man, but it's been a while since I've read it, so I can't remember the mechanism of invisibility right now.

And then there's always Sue Storm. Both predate Trek.

 

[Uplink]

^^

http://en.wikipedia.org/wiki/Invisibility#Examples_in_fiction

--

I always thought Trek cloaks worked via radiation, sending an object out of phase. Though I'm not sure how TOS cloaks worked (or if they even tried to explain them). The earliest light-bending cloak I can remember is in Predator, although I'm sure there were examples before that.

In RL metamaterials are a product of research into making smaller and faster computer chips. Focusing, bending and reflecting light, and then someone thought hey this could be used to make an object invisible A Trek fan I'm sure.

 

[Flying Spaghetti Monster]

there was a picture

 

[BolianAuthor]

I saw this on the news today, and discussed it with my dad... I REALLY don't see how a cloak could ever work on Earth... think about it... ok... we cloak a plane. Fine. But physically, as an object, the plane is still there... thus, any light hitting the plane, would cast a shadow on the ground, giving away the fact that there IS something there. The same with a person... you can cloak the item itself... but the fact of their physical presence remains, and thus, the uncloakable shadow.

Same principle for a boat-cloak... it would be given away by both visible depressions in the water, not to mention a foamy wake that appears to be coming from nowhere.

 

[Lindley]

With a perfect cloak, a shadow wouldn't be a problem. After all, you're not just blocking the light emitted from the object, you're bending the light from behind it around in such a way that you can see what's on the other side without distortion. So shadows are no issue.

The depression in the water would be, unless you were able to fabricate the image of undisplaced water on the fly; and that strikes me as even more impossible than cloaking to begin with.

 

[BolianAuthor]

^

LOL... shadows ARE an issue...

You can bend light any way you want, so that YOU cannot see an object. However... let us say a cloaked airplane flies above you, and passes in front of the sun. The plane is not visible to you... but the fact remains, that a physical object is still crossing the path of the sun's light, and thus, will cast a shadow.

Think of it this way... you have a tree in the middle of a vast grassy plain. You want the tree to seem invisible, so you cover that tree with wrapping paper, that exactly mimics the grassy plain around it. However... the tree is still a physical obstacle, and when the sun's light shines on it, the shadow of the tree will still be cast.

 

[David cgc]

Yes, but the sun's light is being bent around and past the plane, just like the reflected light from the sky, and ground, and clouds, and everything else that the plane is inconspicuously failing to occult.

 

[Lindley]

A perfect cloak would cause the object not to block or significantly deflect (once it leaves the immediate area) any photon, so shadows wouldn't be an issue.

If you were simply projecting an image equivalent to what's on the other side but not using the actual photons that are hitting over there, then intensity information could be lost and shadows would result.

 

[scotthm]

Think of it this way... you have a tree in the middle of a vast grassy plain. You want the tree to seem invisible, so you cover that tree with wrapping paper, that exactly mimics the grassy plain around it. However... the tree is still a physical obstacle, and when the sun's light shines on it, the shadow of the tree will still be cast.

If your cloak redirects the light properly then it doesn't merely 'cover' the object, but redirects light around it. A bright light shining on the cloaked object would illuminate the spot past the object where you would ordinarily see a shadow. At least in theory.

---------------

 

[Aragorn]

Great, with cloaking, how many TrekBBSers will find their way into women's locker rooms?

there was a picture

There... are... FOUR PICTURES!!!

 

[BolianAuthor]

Think of it this way... you have a tree in the middle of a vast grassy plain. You want the tree to seem invisible, so you cover that tree with wrapping paper, that exactly mimics the grassy plain around it. However... the tree is still a physical obstacle, and when the sun's light shines on it, the shadow of the tree will still be cast.

If your cloak redirects the light properly then it doesn't merely 'cover' the object, but redirects light around it. A bright light shining on the cloaked object would illuminate the spot past the object where you would ordinarily see a shadow. At least in theory.

---------------

I absolutely get all of that. But you have to look at it this way... you are on the ground, looking up, at the Sun. Between your line of sight, and the Sun, is another object, say a ball, that has been "cloaked"... ok, fine. The light may be bent over all the surfaces of the ball, but from your point of view, you are looking at the Sun, with a physical object in the way... the light of the Sun covers a lot more area than a ball... we know this, because we squint, when we look towards the Sun, because the light/brightness increases. Therefore, the light of the Sun would extend beyond the surface area of the ball, and the ball would still cast a shadow on the ground, even though, by looking up, we may not see it (the ball).

Here is an example that may help... see this image below, of a forming solar system... now see the small planet that lies in the "Earth zone", in the dust belt. You see how it casts a shadow wake behind it, in the dust cloud? The same would happen if that small planet were invisible to us... it physically is still there, blocking the star's light, so the light of the star would have to go around it. Further, the dust around such a cloaked planet would also still appear to be displaced.

http://www.phys.ncku.edu.tw/~astrolab/mirrors/apod/image/0210/fomalhaut_atc.jpg

This is another reason why a cloaked plane might not work well. If it were to fly through either clouds or fog, it would give itself away, either by moisture forming upon its surfaces, or by displacing the cloud it's flying through, in much the same fashion as how Voyager caused the nebula cloud to move around it, as it flew through it, in the VOY opening credits.

Also, if it were to rain, the rain would be falling AROUND the object that is cloaked.

 

[Lindley]

No, a truely, absolutely, 100% *perfectly* cloaked object could not possibly cast a shadow. A shadow is an area which is less illuminated due to blocked photons. If photons are bent around the object and then returned *precisely* to their original course, no shadow could possibly result, because the photons would be covering the same region they would if it were not present. They might be delayed slightly by being bent around the object, but that would be undetectable except during sudden changes in overall illumination.

Of course, the counterpoint to this is that the cloaked object would exist in perfect darkness, since no photons would be able to hit any visual receptor it might have. (If they did, a shadow would result!)

 

[scotthm]

Here is an example that may help...

I think the point you're failing to recognize is that the light that falls on the cloaked object is not reflected back, but retransmitted to the far side and allowed to then return to its original path. It will not be blocked by the cloaked object, but merely delayed by a small amount while it travels around the object. The observer will be seeing all the light from behind the object as if it were not there. Again, this is the theoretical objective.

This is another reason why a cloaked plane might not work well. If it were to fly through either clouds or fog, it would give itself away....

Also, if it were to rain, the rain would be falling AROUND the object that is cloaked.

I can think of many ways an object with a visible light cloak might be detected, but that doesn't make this technology worthless or uninteresting.

---------------

 

[Data Holmes]

I wonder if they would've ever thought to try if Star Trek hadn't had the idea first. Does the idea of concealing something by bending light around it appear in SF lit prior to TOS?


Marian

I always thought the romulan cloaking device concept was an extension of the myth/legend/belief that the US attempted to/succeeded in creating a visibility cloak with the Philadelphia Experiment. With many of the creative staff of TOS having been ex-military, I'm sure they would have heard the stories.