Ok so, so far I’ve been talking about seeing what is normally hidden without actually touching, removing or breaking anything. But what’s the state of affairs at the other side of this spectrum? Invisibility.
Camouflage is a universal trait of any living thing thing out there and humans have always been preoccupied with its developpement, from using the fur from other animals to stealth bombers. The ultimate camouflage would ofcourse be pure invisibility, so yeah, how close are we to getting an invisibility cloack?
I found this old TED talk from 2013, which you can watch here if you wish: TED talk video. I’ll give you the quick rundown tough:
Basically it mentions that H.G. Wells wasn’t that far off with his theory in the book “The Invisible Man”. The talk might disappoint you however, no true visual invisibility is achieved. The theory they propose does have some interesting arguments though. “Meta-materials” that provide a negative refraction index.
A short refresher:
Refraction is the principle of different materials bending light in different ways, normally the refraction number is positive, measured against a complete vacuum as a reference. (Which has a refraction number of 1, air has 1.000293.) The most famous example to illustrate this phenomena is a straw in a glass of water, seeming oddly ‘broken’ and shifted as shown on the left in the image below. Negative refraction would result in the even more distorted straw deformation seen in the glass on the right.
In theory the property of negative refraction should allow you to bend light in the opposite direction to which you’d normally expect it to go, essentially opening the door to invisibility. If you really want to go deeper into the physics of it I can start you off with these Wikipedia articles on the topic: http://en.wikipedia.org/wiki/Negative_refraction and http://en.wikipedia.org/wiki/Snell%27s_law.
For now the guys from the TED talk haven’t been able to apply it to visible light, but they have been successful in the domain of radio waves. Applying these materials as a cover could be used to make radio towers (like the ones for your mobile phone) invisible to each other, dramatically reducing mutual interference. The meta-material allows electromagnetic waves to be emitted from within but makes incoming radio waves just ‘pass trough’ the antenna.
This again shows how messing around with a certain technology or theory can result in major advances in other areas of technology than intended.
The only thing close to an actual invisibility cloak i could find on the net make use of complicated suits, using camera’s strapped to the back and either LCD/ LED technology ‘clothing’ or using a projector placed in front of the subject. The entire setup is hardly subtle and is very far away from providing true invisibility of any sorts in my opinion.
In short: invisibility cloaks, on our way but far from actually getting there.
So, there’s an evident ethical question to be posed here, do we really want invisibility cloaks to ever be a thing? It didn’t end well for the protagonist in Well’s book, but i won’t ruin the plot for you. Harry potter might have only used his invisibility cloak for doing good in the scenes that were shown to us, but what about all those other times we weren’t told about?!
So, do you personally see more advantages than disadvantages in this technology or do you think this is just another thing that just shouldn’t ever be a thing? Also, where do you think it could actually be handy?
I think this research should just continue, i can see many benefits but I’m going deeper into that in a future blog.
I’d get very paranoid however. But in the end aren’t we all already walking around with devices that could, in principle, listen to everything we hear, say and see ourselves to some extent? I don’t think covering an invisible person with a post-it would do that much.
As a personal extra: what use of invisibility in fiction is your favorite? Mine was in the movie ‘Hollow Man’ also shows the concept of invisibility,if you haven’t seen it, I recommend it as an entertaining watch !