The Surface and
Interior

The surface of Saturn bears many similarities with the surface of Jupiter, but the color contrast is generally less. This is thought to be due to Saturn being colder than Jupiter (further from the Sun), so it has different chemical reactions in its atmosphere, leading to different coloration.

There are large anticyclonic cells on the surface, apparently driven by the planet's internal heat source, but none are as large as the Great Red Spot on Jupiter, and they are not as abundant as on Jupiter. The image adjacent left shows a red anticyclonic disturbance about the diameter of the Earth.


Storms on Saturn

The adjacent animation shows a sequence of Hubble Space Telescope images of the Great White Spot, a disturbance discovered in 1990 that can extend completely around the planet. The same storm is illustrated with greater smoothness in this Hubble Space Telescope movie sequence (Ref).

High-Velocity Winds

There are extremely high velocity winds in the atmosphere of Saturn. Unlike the case for Jupiter, the variations in wind speeds are not strongly correlated with the positions of the belts and bands. The wind speeds in the atmosphere of Saturn have been measured to be as high as 1800 km/hr, which is about 4 times the highest speeds in the atmosphere of Jupiter.

The Interior of Saturn

Like Jupiter, Saturn is largely liquid. The slightly lower concentration of helium relative to hydrogen in the atmosphere of Saturn compared to Jupiter is thought to be be due to the colder temperature of Saturn. Under these colder conditions, liquid helium does not dissolve in liquid hydrogen and drops of helium sink to the center, depleting the outer regions in helium. Speculation on Saturn's internal heat source is similar to that for Jupiter.

The magnetic field of Saturn is similar to that of Jupiter, but weaker. Electrical currents in liquid metallic hydrogen deep in the interior are assumed to be the cause of the magnetic field. The magnetic field traps charged particles in "Van Allen belts" similar to that of the Earth. (Jupiter also traps particles but the belts are more extended in radius and thus are more like annular sheets. Saturn has less extensive of a trapped charged particle region than Jupiter.)