Several news outlets have claimed that scientists have created a “cloaking device” like those seen on Star Trek, but that isn’t quite what happened. The cloaking devices on Star Trek bend light to render an object invisible, and the new device merely deflects sound. The technology also isn’t so new, as others are working on devices such as these. It’s still cool, though.
Photo: Peter Kerrian
The device being covered in the news today is a metamaterial – an engineered object with specific properties unlike those found in a regular old machine shop. Some of these materials display mind-bending physical properties, others are the blackest black, and others are “anti-magnets”. One potentially important metamaterial would be one that could control the direction of sound waves.
Penn State researchers, led by research associate Amanda Hanford, set out to create a metamaterial that could scatter sound waves underwater. Sonar works by sending vibrations through the water, which bounce off a target and back into a detector. A specifically-designed metamaterial could potentially deflect the waves so they don’t return to the detector.
This week, the researchers debuted their attempt at creating a sound-scattering metamaterial at the 175th Meeting of the Acoustical Society of America in Minneapolis. The researchers created the 90cm perforated steel pyramid shown above, put it in a tank of water, and hit it sound waves between 7000 and 12000 Hz in frequency. The material seemed to deflect the waves, based on the readings in the tank’s receivers.
This is still early days: Obviously, this material was a pyramid in a tank, and not a submarine in the ocean subjected to real sonar. Nor was it a cloaked spaceship. And others are researching similarly-shaped materials that also change the direction of sound waves. Other scientists are researching more Star Trek-like electromagnetic cloaking devices as well. The Penn State researchers have not yet responded to a Gizmodo request for comment at time of writing.
So, no Star Trek style cloaking device yet, just specially-engineered pyramids in the lab. But maybe one day.
[Phys.org]