Robot Explorers: US Unmanned Space Missions: page 13 |
| Scientists have long sought to determine what the rings around Saturn are made of, how they got there, and what keeps them in orbit around Saturn. The discoveries of the two Voyagers, which arrived in November of 1980 and August of 1981 shed some light on the mysterious rings. Saturn is made up of the same materials as Jupiter, but in a different mixture. Saturn radiates 80% more energy than it absorbs from the Sun. Even with its self-manufactured heat, Saturn's atmosphere, compared to Jupiter's, is much less active. It does, however, have a high-velocity equatorial jet stream that blows around 1100 miles per hour. | |
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| Saturn's rings have long been acknowledged as one of the finest sights in the solar system. These rings actually have an intricate structure, with the material in them ranging from dust sized to boulder and house-sized particles. Although the diameter of the rings stretches out more than 250,000 miles, they are not much thicker than the largest particles that make them up. The rings are thought to be the remnants of large moons that were shattered by impacts of comets or meteoroids. The irregular shapes of the smallest of Saturn's 18 known moons suggest that they too are fragments of larger bodies. The rings contain several narrow gaps, some occupied by still more rings unseen from Earth. The wavy edges found in some of the rings were associated with shepherding moons, small satellites orbiting within the ring plane. The elaborate structure of some of the rings is due largely to the gravitational effects of these moons. | |
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Titan, the largest moon of Saturn has a diameter of 3200
miles. It is covered with an orange photochemical haze too thick to see through. The
chemistry in Titan's atmosphere may strongly resemble that on primeval Earth between three
and four billion years ago. Dione, Saturn's fourth largest satellite, has a cratered, icy surface. |
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Tethys has also undergone internal stresses, as indicated by a valley extending more than half the moon's circumference. Another moon, Mimas, showed a crater so huge, 81 miles in diameter, that the impact that caused it nearly broke the satellite apart. |
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Copyright ©2004 Colleen Gino |
Images courtesy JPL and NASA. |
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