|Physics World: artist conception of nano particles (NP)|
Physicists in Germany have developed the first-ever "nano-ear" capable of detecting sound on microscopic length scales with an estimated sensitivity that is six orders of magnitude below the threshold of human hearing. The device is based on an optically trapped gold nanoparticle, and its inventors claim that it could be used to "listen" to biological micro-organisms as well as investigate the motion and vibrations in tiny machines.
I wasn't kidding.
Physics World: Introducing the 'nano-ear'