ROUND AND ROUND
Jupiter is still cooling off from its formation, and the heat fuels phenomena ranging from the planet's immense magnetic field to convection currents in its clouds. The light-colored zones tend to be high, cool clouds in regions ofupdrafts, while the darker belts mark warmer areas of downdrafts.
Jupiter's rapid rotation—less than 10 hours—smears the cloud features into east-west stripes paralleling the equator. This rapid rotation also causes
Jupiter's marked oval shape— the planet is 7 percent wider at its equator than at its poles.
Lacking a solid surface,
Jupiter displays differential rotation, like the Sun does.
The period for System (the equatorial zone) is 9 hours
51 minutes, while System II
(the higher latitudes) rotates a bit more slowly and has a period of 9 hours 56 minutes.