  11/5/80 9 million km (5.5 million mi) Saturn is the sixth planet from the Sun and second largest in our solar system. Like Jupiter, it is a giant sphere of gas—mostly hydrogen and helium—with a possible core of rocky material. Various features in Saturn’s cloudtops are visible in the accompanying color-enhanced image of the planet’s northern hemisphere: small-scale convective cloud features (similar to, but much larger than, thunderstorms in Earth’s atmosphere) are visible in the brown belt; an isolated convective cloud with a dark ring is visible in the light brown zone; and a longitudinal wave is visible in the light blue region. 9/17/80 76 million km (47 million mi) As Voyager 1 approached Saturn, a series of dark and light cloud bands (belts and zones) became apparent in the planet’s northern hemisphere through a high altitude atmospheric haze. The planet’s shadow obscures the rings behind and immediately to the east of the disk. In addition, the shadow of the rings on the planet’s disk can be seen just north of the rings themselves as they cross in front of the planet. Six of Saturn’s 15 known satellites are visible. Saturn’s largest moon, Titan (considerably larger than Earth’s moon), is clearly visible in the upper left corner. The smaller satellites Dione, Tethys, and Rhea are shown in the lower left corner (upper, middle, and lower, respectively). Two of the innermost moons, Mimas and Enceladus, appear to the right of the planet (Mimas is the one closer to the planet). These six moons orbit Saturn in the equatorial plane and appear in their present positions because Voyager is above that plane. 10/18/80 34 million km (21 million mi) The North Temperate Belt is visible as the violet-colored belt in this false-color photograph. In this image, features which are especially bright in ultraviolet light appear as turquoise and violet, while ultraviolet-dark areas appear orange. Notice in particular the three spots (two bright orange and one pale violet) at mid-northern latitudes. The bright spots are similar to those shown at much higher resolution in later images. The distinct color difference between the North Equatorial Belt and Saturn’s other belts and zones may be due to a thick haze layer covering the northern portion of the belt. It is not yet understood why the southern hemisphere of the planet (below the rings) appears bluer than the northern hemisphere. Color spots in the rings are artifacts of image processing. 10/30/80 18 million km (11 million mi) Saturn’s soft, velvety appearance and previously unseen detail in its mysterious rings became visible as Voyager 1 approached the planet. For example, a gap in the dark C-Ring is now visible, and material can be seen within the relatively wide Cassini Division (long believed to be empty), which separates the B-Ring (middle) from the A-Ring (outer). The Encke Division appears near the outer edge of the A-Ring. Detail can be seen within the shadow cast by the rings upon the planet: the broad, dark band near the equator is the shadow of the B-Ring; the thinner, brighter line just to the south is the shadow of the less dense A-Ring. Three of Saturn’s moons, Tethys (outer left), Enceladus (inner left), and Mimas (right) are also visible in this computer mosaic of Voyager 1 images. 11/6/80 8.5 million km (5.3 million mi) An unusual red oval cloud feature, similar to (but smaller than) Jupiter’s Great Red Spot, was discovered in the southern hemisphere of Saturn. The oval, 6000 kilometers (4000 miles) in length, is located at 55 degrees south latitude. The difference in color between the red oval and the surrounding bluish clouds in these two false-color images indicates that material within the oval contains a substance that absorbs more blue and violet light than the bluish clouds. Voyager scientists first observed the oval in August 1980, and the feature has retained its appearance since its discovery. 11/6/80 8 million km (5 million mi) In this photograph, the shadow of the satellite Dione is seen as a dark circle on the face of the planet. 11/10/80 3.5 million km (2.2 million mi) A ribbon-like wave structure and small convective features marking a westward jet stream above the wave are visible in this photograph of Saturn’s cloudtops. The view, extending from 40 degrees to 60 degrees north latitude, shows features 65 kilometers (40 miles) in diameter. Measurements in images such as this one indicate that Saturn has fewer east-to-west wind currents than does Jupiter. 11/12/80 442,000 km (265,000 mi) Numerous small cloud features were photographed as Voyager 1 passed above Saturn’s southern hemisphere. At these polar latitudes, the large-scale light and dark bands break down into small-scale features, seen here as waves and eddies. 11/7/80 7.5 million km (4.6 million mi) Two brown ovals, approximately 10,000 kilometers (6000 miles) across, were discovered in Saturn’s northern hemisphere, at about 40 degrees and 60 degrees latitude. The polar oval (upper left) has a structure similar to Saturn’s red oval located in the southern polar latitudes. Detail within the ovals is not visible at this resolution, so it is not yet known if they are rotating features similar to the many spots in Jupiter’s atmosphere. |
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