How Not to be Seen

Humans have long been fascinated by the concept of invisibility. From H.G. Wells’ Invisible Man to Harry Potter’s cloak of invisibility, purveyors of fiction have pondered what one would do if one could move about unseen. Invisibility is often portrayed as a perfect transparency– ala the Invisible Man– however this method is in conflict with the laws of nature as we understand them. Moreover, a transparent person would be plagued with a host of difficulties that seem quite insurmountable. Any consumed food or drink would be embarrassingly visible as it meanders through the digestive system, and these visible nutrients would immediately begin to integrate into the body. That’s to say nothing of wardrobe problems and social difficulties.

The competing approach to invisibility involves some sort of cloaking device to route photons around an object. This method is somewhat more feasible, but of course it comes with its own unique set of complications. For instance, if all the outside light is diverted around something, no light is able to reach an observer inside, leaving them unable to see out.

These difficulties and others have long left all serious speculation about invisibility lodged safely in the distant future. But this is no longer so. In October of 2006, Professor Sir John Pendry of the Imperial College London announced the successful creation of a rudimentary cloaking device which nudges the idea a bit closer to reality. Perhaps most surprising of all, the whole concept rests on a fairly simple physical principle of light– one that requires no electricity to operate, and that every high-schooler learns in basic physics.