Credit: ELSEVIER

Icarus doi:10.1016/j.icarus.2009.10.006 (2009)

The fast-flowing gas currents that give the giant planets their banded appearance may be caused by energy released when water condenses into clouds and storms. Jupiter (pictured, top) and Saturn (middle) have 20 to 30 of these jet streams, including a broad eastward jet that flows around the equator. Uranus and Neptune (bottom) each have only about three, with a westward jet at the equator.

Yuan Lian and Adam Showman from the University of Arizona in Tucson used simulations to show that the heat produced when water condenses during storms could drive jet streams matching those observed on all four planets. They found that expected differences in water abundance on the planets could account for the distinct stream patterns.