If you're a fan of science fiction or fantasy, then you're probably familiar with the concept of invisible cloaks or cloaking devices. How cool would it be if we could slip on a ring, ala Lord of the Rings, or strap on a robe that would make us invisible?
No such device exists, of course, but theoretically, it could, and at least some scientists think that we have the materials and know how to make invisibility a reality.
Here's how it could work. Things are visible because they block light waves and make them scatter. This disruption of the movement of light is what "reveals" objects, so to speak, or at least makes them visible to the human eye. Theoretically, then, causing light waves to move seamlessly around an object instead of smacking into it could render the object invisible.
The trick, of course, is in getting light to behave in this way. Can it be done? Some theorists think so. All we need is material engineered at the atomic level to interact with light waves in such a way that creates no reflection or shadow. The result would be that light waves flow around the object like water in a stream flows around a protruding log or rock.
These kinds of materials do not yet exist, but the calculations behind them do. Scientists at Duke University have created a blueprint providing a mathematical description of how a cloaking material would work. The next step then, perhaps more difficult, is using the math to actually create a material capable of making things invisible.