Bacteria in a drop of water spontaneously form a bi-directional vortex, with bacteria near the center of the drop swimming in the opposite direction of bacteria swimming near the edge. New computer simulations, confirmed by a novel experiment, explain how that vortex comes to be.
PROVIDENCE, R.I. [Brown University] — When a bunch of B. subtilis bacteria are confined within a droplet of water, a very strange thing happens. The chaotic motion of all those individual swimmers spontaneously organizes into a swirling vortex, with bacteria on the outer edge of the droplet moving in one direction while those on the inside move the opposite direction. (more…)