World Wide Words

From the Turns of Phrase section

Oscillon

Photographs show vibrating heaps of tiny brass balls forming themselves into patterns; fascinating, but hardly the stuff of fundamental science, one might think. But some deceptively simple experiments at the University of Texas at Austin may have discovered a completely new phenomenon, which may just be the basic building block of all patterns everywhere. The experiments are reminiscent of those school science projects in which we dusted sand on to a metal plate, made it vibrate using a bow and observed the patterns formed, which go by the name of Chladni figures. The researchers realised that these figures say more about the vibrations in the plate than in the sand and created an experimental setup — using a shallow layer of those brass balls in a vacuum — that minimised outside effects. When they vibrated the plate at a critical amplitude, they found that the balls spontaneously formed a localised vibrating column which lasted indefinitely. They named this self-sustaining state the oscillon, by analogy with its closest large-scale analogy, the soliton, which is a localised wave that maintains its integrity as it moves (bores on rivers are solitons). Nobody quite knows what to make of oscillons at the moment: they clearly have connections with the mathematical theory of chaos and may give insights into the way atoms organise and interact.