The Possibility of Making Objects Invisible Using Sound and Light

[striker1649]

I herd that a group has discoverd a way to bend sound around an object. Now if we can do that there is was to do that with light, right. So that would make that object invisible. Is this theory correct.

 

[Gokul43201]

No, it isn't.

 

[striker1649]

well if you learn how to bend light, dosent that mean you can bend light around an object and make it so you can't see that object.

 

[ZapperZ]

Maybe you should start by first citing this "source" that you heard this news from. It is very difficult for the rest of us to figure out if (i) you heard it wrong (ii) you misinterpreted the news (iii) you heard some crackpottery or (iv) you imagined it.

Consider this to be something of an unofficial requirement for this forum. Anyone who wants the rest of us to comment on a piece of news should make a clear citation of the source. Or else, all of the subsequent discussion will be ambiguous, or even moot if the news itself was misinterpreted.

Zz.

 

[Edgardo]

Here's something I found on physicsweb.org:

http://physicsweb.org/articles/news/10/5/16
http://physicsweb.org/articles/world/19/9/5/1
http://physicsweb.org/articles/news/10/10/12

Ulf Leonhardt's homepage:
http://www.st-andrews.ac.uk/~ulf/

An article:
http://www.dukenews.duke.edu/2006/10/cloakdemo.html

Video on youtube.com:

 

[disregardthat]

Well, if you COULD bend light around an object and make it go straight when it is on the other side, you could in theory make the object invisible. The only problem is that there is no known way to do it.

 

[Ki Man]

you can curve light with strong electrical charges can't you?

I think that in order to make it invisible you would have to have something pulling the light away from it on one side so that no light is reflected of the object, and you would need something forcing the light back into its original path once its on the other side of the object. unless you can find a way to do that from every possible angle, it would only be invisible from a certain point by light hitting it at a certain angle.

maybe one day possible but I don't think it would be practical

 

[swerdna]

well if you learn how to bend light, dosent that mean you can bend light around an object and make it so you can't see that object.

I think you might get more of a “double exposure” effect as light doesn’t block light.

 

[ZapperZ]

Here's something I found on physicsweb.org:

http://physicsweb.org/articles/news/10/5/16
http://physicsweb.org/articles/world/19/9/5/1
http://physicsweb.org/articles/news/10/10/12

Ulf Leonhardt's homepage:
http://www.st-andrews.ac.uk/~ulf/

An article:
http://www.dukenews.duke.edu/2006/10/cloakdemo.html

Video on youtube.com:

I was waiting for the OP to actually cite this as the source of this "bending" of light. I believe this issue has already been addressed somewhere on PF already.

If it is this "cloaking" effect, then it isn't a "bending" of light. The metamaterials used (i.e. the split-ring resonators) actually produces a material with a negative index of refraction. One of the uses of such a material is that it causes light to be refracted in the 'wrong' way. In this particular case, the light is absorbed and retransmitted by the material, much like what you have when light passes through glass. Thus, it appears as if the material itself is "invisible".

Note however that metamaterials like this only has a very, very narrow bandwidth where it behaves in this exotic fashion and only in a particular direction. So far this effect has been demonstrated for a particular frequency only in the microwave spectrum. The very fact that we CAN physically see the material with our own eyes means that it can't do this yet with visible frequencies.

However, if you look at the OP, you'll notice why I don't think this is what is being asked, or referred to (i.e. this is not 'sound' being bent).

Zz.