![]() ![]() Others have developed a flexible cloak that wraps around a small object to make it vanish, but only at one wavelength. Since then, researchers have made small inanimate objects and a fish, a cat, and a hand vanish under ordinary visible light, but only as seen over a narrow angle of view. Placed around an opaque metal object, the cloak made the object nearly completely vanish under microwave radiation. Researchers first tested this idea in 2006 with a rigid metamaterial cloak, a hollow cylinder whose wall held thousands of small structures that made microwaves traverse suitable paths within the wall. In principle, an invisibility cloak could intercept those incoming rays and the observer, seeing what looks like undisturbed light, would think nothing is there. INVISIBILITY CLOAK: We see an object as it interacts with incoming light. But to make light follow this complex path, the cloak needs to be made from a metamaterial. An observer, seeing what looks like undisturbed light, would think nothing is there, just as flowing water smoothly splitting around a rock and then recombining gives no downstream indication of the rock. In principle, an invisibility cloak could intercept those incoming rays and bend or refract them into itself so they travel inside the cloak and emerge along their original paths. We see an object as it interacts with incoming light. Physicists don’t yet know how to do that, but the classical optics of light waves and light rays points to another solution. This uses an idea from relativity, that strongly distorted spacetime makes light curve around the spacecraft as if it didn’t exist. Invisibility shows up in science fiction too, like Star Trek, where hostile Romulan spacecraft conceal themselves with a cloaking device. The magical invisibility rings and cloaks featured in fantasy stories reflect the ancient human dream of hiding things and people from sight. Nautilus Members enjoy an ad-free experience.
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