THE SURFACE OF SATURN

S aturn is one of the giant outer planets, which are characterized by their large size, low density, and corresponding extensive atmospheres. Current models of the interior indicate that below the relatively thin cloud layer is an extensive, clear hydrogen-helium atmosphere. Data that has been from Saturn helps to confirm these theories. As you approach the core of the planet, gas becomes more dense until it becomes a liquid. Further down in Saturn's core the pressures increase to such a high degree that hydrogen becomes metallic. A small core of silicate material probably exists at the very center.

S aturn's weather consists of easterly and westerly jet streams that reach a speed of 480 m/sec (1,070 mph). These jet streams do not change very often but as the Voyager spacecraft images show, the cloud cover can change in a matter of hours. A northern hemisphere feature, known as the Great White Spot, only becomes viable from Earth about every 29 years. The spot is apparently an accumulation of ammonia-rich materials which crystallize to produce the white color. The spot sometimes expands until it envelops an extremely large area of Saturn.

T races of methane, ethane, phosphine, and acetylene also exist in the hydrogen-helium atmosphere. Various colors that have been observed probably result from the interaction between trace elements like sulfur or carbon, and ions produced by lightning. This condition of chemical nonequilibrium is produced by the mixing of elements that is caused by the heat and gravity of Saturn. Saturn radiates 2 to 3 times the amount heat that is absorbed from the Sun.

S aturn has a strong, bipolar magnetic field, as well as a magnetic tail that extends in the direction away from the Sun much like cometary plasma tails. Saturn's magnetic field traps charged particles coming from the solar wind. These particles are absorbed by satellites and ring particles.

S aturn is far enough away from the Sun to retain the light elements (hydrogen and helium) and has a solar-like chemical makeup. Saturn's mass, unlike that of the Sun, was not large enough to initiate the fusion process. Unlike Jupiter, Saturn did not give off enough excessive heat to drive out water from the inner satellites.

S aturn has the most extensive satellite system in the solar system. Not counting its intricate ring structure, more than 20 bodies orbiting around Saturn have been identified. Six can be easily seen through the telescope.