invisibility cloak

Today's stealth fighters, such as the F-22 Raptor, may do pretty well in concealing their radar signature, but mathematicians say that a new active cloaking technique could someday generate electromagnetic fields to hide submarines from sonar, or even protect buildings from earthquakes.

Disaster film director Roland Emmerich must be quaking in his boots knowing that his movies may soon have to be a little less destructive. With the invention of an "invisibility cloak" for buildings, earthquake damage could be significantly minimized. Using a series of concentric rings in the foundation of a building, this "cloak" directs seismic waves around a building, rather than destructively against and through it.

It's like something out of a science fiction novel or a Harry Potter book. Engineers from Duke University have constructed a device that can "cloak" items placed on a mirror surface.

First designed in 2006, the new version of the device is a more sophisticated and complicated design that can cloak a wider variety of waves.

In our October issue, we reported on the theoretical and practical work being done to make the fantasy of invisibility a reality [read the article online here]. Yesterday one of those teams of researchers—a Duke University group led by David Smith—announced that they had demonstrated the worlds first working invisibility cloak. And unlike other cloaks, which use images projected onto the surface of the item to be hidden, Smiths actually bends light around the object, making the light behave as if the object isnt even there.

The cloak, which is less than five inches long, is a synthetic structure composed of copper rings and wires placed onto sheets of fiberglass. Its applicability is limited: It works for only two dimensions and only against a microwave beam. The technology to create an invisibility cloak for regular light, which is made of many different wavelengths, is still decades away. See a video of the new cloak here. —Abby Seiff

Related:The First Invisibility Shield