When a crowd of bacteria (mostly composed of carbon) gathers in a droplet of water, a synchronized round dance begins: millions of tiny ones glide along giant ellipses, like dancers on a ballroom floor. Without a conductor, complex patterns emerge from simple movements. The language of this dance is the liquid streams each cell squeezes around itself.
The key to the puzzle is the bacterium’s ability to slightly outpace the flow: it swims faster than the water, like a dancer bursting a fraction of a beat ahead. When cells are abundant and the liquid film is thin, these tiny thrusts add up into collective synchronized rotation. And here’s the surprise: all this order relies on bacteria continuously pumping entropy outward — dumping disorder into the water while keeping structure within.
The same mechanism applies to any elongated particles swimming in a fluid — from biological fibers to artificial microrobots. The foundational ideas of Ludwig Boltzmann, Henri Poincaré, and Daniel Bernoulli converge to explain this microbial round dance. The whole scene rests on hydrogen bonds in water.
To synchronize their dance, bacteria use the same principle as neurons in our brain when creating rhythms — only the connection is water-based, not electrical.
In the novel Solaris, the ocean thought using flow physics — bacteria do the same on a droplet scale.