The Marvelous Physics of Swarming Midges
The New York Times
There’s more in that cloud of bugs than meets the eye.
On early autumn afternoons across the temperate world, the midges are now gathering to swarm: clouds of tiny flies, wings lit by the sun like so many sparks, swirling in patterns too quick and complicated for the eye to follow but leaving a mental afterimage of order. Not a perfect order, but something more than chaos.
That impression of order is accurate, according to scientists who study such swarms: In the movements of midges, one can find the mathematical signatures of properties beyond what one would expect from a cloud of bugs. As a group, they behave like liquids or gases, and even exhibit the characteristics of “criticality,” that uncanny stage of matter at which radical transformation from one state to another occurs in a blink.
“Collective correlation can emancipate the system from its microscopic details,” said Dr. Andrea Cavagna, a physicist at the Institute for Complex Systems in Rome. A swarm is much more than its midges.
