Much as we'd love to discover grey aliens with warp drive technology, any extraterrestrial life we're lucky enough to find will likely be pretty basic. But the chemical detection methods used by space probes like Curiosity or Philae are hit-and-miss -- they can't actually tell if something is alive or not. Scientists in France have developed a new nanosensor that may help: a simple cantilever with a laser motion sensor that can accept about 500 bacteria. As long as they're alive, the cells will cause minute vibrations on the cantilever, which are captured by the lasers as a sign of life. After scientists kill the cells, the signals stop.