# Mathematical Digest

### Short Summaries of Articles about Mathematics

in the Popular Press

"Unweaving the whirls," by Joël Sommeria. *Nature,* 11 October 2001,page 575.

This one-page article gives a brief and lucid description of turbulence, aconcept that applies to complex, agitated, eddy-filled flow in fluids of allkinds, from Jupiter's great red spot to the oceans on earth. The Navier-Stokesequations provide a mathematical description of fluid flow, but they cannotpredict turbulence. While computer simulations have helped, they are stillnot detailed enough to provide the needed insights. The article discusses someof the main challenges facing scientists trying to understand turbulence."There will be no single breakthrough," the article states. "[W]e face deepquestions about information processing and probabilities, and about the verymeaning of scientific understanding and prediction."

*--- Allyn Jackson*