Thursday, June 6, 2013

How to cloak a Fisher space pen...or a satellite

There's an apocryphal story that, faced with the fact that ballpoint pens don't work in zero gravity, NASA paid a lot of money to develop the Fisher space pen. Meanwhile, the Russians used pencils.

That story isn't really true, but I thought of it today when flipping through Technology Review's Physics arXiv blog and saw a clever paper on cloaking devices by a Rochester physics professor and his son, who's apparently still in middle school.

Cloaking experiments pop up every few years, and everyone gets really excited because, let's face it, it's pretty awesome to put on an invisibility tee shirt. But cloaking devices have problems. Some of them work only on a narrow range of light frequencies, and others can't hide anything of appreciable size, like, say, a person.

Enter the Howells, John and Benjamin. Where every other research team went high tech, they went decidedly low tech and used tools magicians have known about for approximately forever. Using tanks of water, Fresnel lenses, and mirrors — no smoke, though — along with some clamps and scraps of wood, they successfully cloaked toy helicopters, chairs, and other things they found laying around.

Despite the fun and games, the "why didn't I think of that?" solution might actually have some practical value. Because it's easy to build big mirrors, such devices could be used to disguise satellites or maybe buildings, just as long the magicians can distract you from what they're really doing.