How Small Can Life Be? SpaceDaily

As advanced microscopes enable us to peer deeper into the realms of inner space, biologists have been faced with a vexing question: Is there a size limit on life? If so, then just how small can something be before it can no longer be defined as “life”? Some scientists believe that life can be very small indeed. Called nanobes, nanobacteria, or nano-organisms, these miniscule structures borrow their name from their unit of measurement, the nanometer. A nanometer is one billionth of a meter. That’s about the length of 10 hydrogen atoms laid out side by side. The period at the end of this sentence is approximately one million nanometers in diameter.