Figure 12-11: Original Model of Jupiter’s Belts and Zones The light-colored zones and dark-colored belts in Jupiter’s atmosphere were believed until recently to be regions of rising and descending gases, respectively. In the zones, gases warmed by heat from Jupiter’s interior were thought to rise upward and cool, forming high-altitude clouds. In the belts, cooled gases were thought to descend and undergo an increase in temperature; the cloud layers seen there are at lower altitudes than in the zones. Observations by the Cassini spacecraft on its way to Saturn suggest that just the opposite might be correct, with the darker belts rising (these new doubts are indicated by the question marks in the figure above). Cassini was able to spot numerous small clouds—too small to be identified from Earth—rising within the dark belts, suggesting that the belts themselves might be rising.