From Jim Bier:

Re: Hexagon on Saturn mystifies astronomers (March 27): I have observed a similar hexagon in an ordinary coffee cup in the top surfce on occasion. I just related it to hexagonal convection cell, presumably falling around the outside, and being replenished from the inside. Why a hexagonal shape to the cell??? Beats me. But if it can occcur in the fluid of a coffee cup, it apparenly can occur in the fluid of a mostly dense gaseous planet.

Jim Bier
Professor of Chemistry
Ferrum College
Ferrum, VA