Microelectromechanical systems, or MEMS, play a key role in gyroscopes, tiny chemical sensors, optical switches used in the telecom industry, and more. An even smaller version of the technology--nanoelectromechanica­l systems, or NEMS--could likewise have broad technological importance. Vera Sazonov­a has made the world's smallest NEMS device: a tiny resonator that consists of a single carbon nanotube suspended over a silicon gate. A voltage at the gate makes the nanotube vibrate, creating a high-frequency current. Since the current is hard to detect, Sazonova applied another voltage at a slightly different frequency; the two signals mix to create a third, low-­frequency current that is easier to pick up. Potential applications include ultrasensitive motion detectors, sensors that can detect the mass of molecules, and even devices for detecting gravitational waves. --Prachi Patel