Voyager 1 spots two new moons, foresees a heavenly waltz
Every December the ancient Romans indulged in a colossal round of drinking, carousing and tumultuous revelry. The orgiastic festival, perhaps coinciding with the winter planting, was staged to propitiate Saturn, the sickle-wielding deity of agriculture. Now scientists gathered at the Jet Propulsion Laboratory in Pasadena may be tempted to hold their own Saturnalia. Next week, after traveling for more than three years, their robot Voyager 1 spacecraft will achieve its closest encounter with Saturn, providing the most spectacular view yet of the beautifully ringed planet and its system of moons.
After nearly four centuries of telescopic observation, astronomers know Saturn is a giant, rapidly spinning ball of hydrogen and helium, surrounded by rings of icy debris and numerous satellites, including the largest moon in the solar system. Still, many questions remain. What are Saturn's rings made of? Can they be traced back to the solar system's origin 4.6 billion years ago, or did they evolve later from the breakup of passing objects captured by Saturn's gravity?
Equally perplexing, since scientists figure Saturn should have cooled off ages ago, the planet is radiating more heat back into space than it receives from the distant sun. What is the source of this mysterious energy? Perhaps the most tantalizing question concerns Titan, Saturn's largest satellite (even bigger than Mercury) and the only moon in the solar system with a thick atmosphere. Could it harbor organic molecules, the precursors of life?
Voyager 1, weighing a scant 825 kg (1,820 Ibs.) and drawing its electricity from a compact nuclear power pack, is ideally equipped to answer such questions. One of two identical ships en route to Saturn (its twin will reach it next August), the spacecraft carries eleven instruments, including two television cameras. During Voyager's swing by Jupiter in March 1979, these keen eyes sent back stunning closeups of the planet's turbulent atmosphere, detailed views of its moons and even a spectacular shot of a volcanic eruption on the Jovian satellite lo.
Since August the robot has been performing its magic on Saturn. Pictures already transmitted by Voyager show light and dark horizontal bands in Saturn's atmosphere as well as ovals and whirls that are apparently great storms. And Saturn's moons, until recently only flecks of light in earthly telescopes, have become clearly distinguishable little orbs.