Looking for life on other planets is not straightforward. It usually relies on chemical detection, which might be limited or even completely irrelevant to alien biology. On the other hand, motion is a trait of all life, and can be used to identify microorganisms without any need of chemical foreknowledge. Scientists have now developed an extremely sensitive yet simple motion detector that uses a nano-sized cantilever to detect motion.

The idea comes from the technology behind an atomic force microscope, uses a cantilever to produce pictures of the atoms on a surface. The cantilever scans the surface like the needle of a record player, and its up-and-down movement is read by a laser to produce an image. The new motion sensor works the same way, but a sample is attached on the cantilever itself. If the sample is alive, it will inevitably move in some way,. That motion also moves the much smaller and sensitive cantilever, and it is captured by the readout laser as series of vibrations. The signal is taken as a sign of life.