Update: Listen to this story on WBUR's Here and Now.

Original story (Feb. 28): You know how on cop shows, suspects get interrogated in a cramped room with a mirror on one wall? And on the other side, there's a prosecutor or other cops watching through the glass.

Those mirrors are kind of an illusion done with lighting. But the effect also illustrates perfectly how difficult it can be to break a pretty fundamental law of nature.

A group of engineers at UT has figured out how to bend – if not break – that law when it comes to sound.


Every year in the U.S., dozens of firefighters are killed in the line of duty. But there are hundreds more close calls, where a firefighter needs to be rescued after becoming injured or otherwise incapacitated. Virtually all firefighters, both volunteer and professional, rely on a simple device designed to alert their fellow firefighters when they need help.