This comparison shows Saturn's north temperate region as viewed Nov. 5, 1980, by Voyager 1 (left) and Aug. 21 by its sister craft, Voyager 2, from a range of 5 million kilometers (3.1 million miles). The large bright oval feature in the lower right of each frame measures about 2,500 km. (1,550 mi.) across. This feature, a gigantic storm system in the planet's atmosphere, was first observed by Voyager 1 almost exactly one year ago. Thus, as on Jupiter, some storms in Saturn's atmosphere are quite long-lived compared to their smaller terrestrial counterparts. By contrast, the pattern of convective disturbances to the north (upper right) undergoes rapid changes in a matter of even a few days. In some respects, these features resemble gigantic thunderstorms. The largest bright feature in the Voyager 1 photograph extends about 7,500 km. (4,650 mi.) from north to south. These giant storms lie within one of the strongest westward-flowing currents observed in the atmosphere, with wind speeds of about 20 meters-per-second (45 mph). The smallest visible features here are about 100 km. (62 mi.) across. The Voyager project is managed for NASA by the Jet Propulsion Laboratory, Pasadena, Calif.