Tiny travelers take on a viscous world
Michael Phelps, one of the greatest swimmers of all time, propels himself forward by hurling water behind his body. If he were the size of a bacterium, though, that strategy wouldn’t make much of a splash. In a microworld Olympics, Phelps would go home medalless.
At tiny scales of 10 micrometers and below, life is largely conducted as if in a thick fluid, where every motion is immediately dampened by the highly viscous muck. Here, where water seems to take on the consistency of honey, the coasting inertia that helps carry Phelps through the water is simply nonexistent.
“It’s like looking at a completely different world,” says Piotr Garstecki, a physicist at the Institute of Physical Chemistry at the Polish Academy of Sciences in Warsaw.
Many microbes spend their whole lives swimming, and it’s not to win Olympic gold. They make their way through the thick morass to find food, locate mates and seek out or avoid light. But exactly h