  11/12/80 717,000 km (444,000 mi) The rings of Saturn have amazed and intrigued astronomers for over 300 years. Now that we have seen them up close, they are even more astonishing. Although they stretch over 65,000 kilometers (40,000 miles), they may be only a few kilometers thick. The ring particles—from a few microns to a meter (three feet) in size—have been described as icy snowballs or ice-covered rock. Voyager scientists continue to pore over their data, searching for answers to the puzzles of the rings. The rings were named in order of their discovery, so the labels do not indicate their relative positions. From the planet outward, they are known as D, C, B, A, F, and E. 10/25/80 24 million km (15 million mi) Extraordinarily complex structure is seen across the entire span of Saturn’s ring system. The sequence (taken approximately every 15 minutes as Voyager 1 approached Saturn) proceeds from top to bottom in each column and shows radial “spokes” rotating within the B-Ring. The spokes may be caused by a combination of magnetic and electrostatic forces. 11/6/80 8 million km (5 million mi) Over 95 individual concentric features can he counted; the final count in higher resolution images may be anywhere from 500 to 1000 separate rings. A few of the ringlets shown in this computer-assembled mosaic are not concentric circles but are instead elliptical. Ring particles are probably ice or ice covered rock. The classic features of the rings are illustrated in the diagram.
11/8/80 6 million km (3.7 million mi) The Cassini Division is filled with numerous ringlets. Discovered by Cassini in 1675, this area between the A- and B-Rings had long been thought devoid of material. The Voyager observation of well-defined rings within the Cassini Division was an unexpected discovery. 11/12/80 740,000 km (460,000 mi) Saturn’s ring system, viewed from below, appears dramatically different from its appearance on the sunlit side. This computer-processed image shows the F-Ring circling outside the A-Ring, the A-Ring with its Encke Division, the multiple ringlets in the Cassini Division, and the optically thick B-Ring, seen here in magenta hues (the coloration is an artifact of processing and is not real). The B-Ring appears dark from below the ring plane because it is dense enough to reflect most of the sunlight, causing it to appear very bright when seen from the sunward side. The opaline brightness of the Cassini Division here indicates a great deal of sunlight being scattered through this region. The Encke Division may really be empty, since it appears dark from both above and below. 11/12/80 720,000 km (450,000 mi) Outbound and above the ring plane, Voyager 1 gave us this view of Saturn’s rings eight hours after its closest approach to the planet. The unique lighting accentuates the many hundreds of bright and dark ringlets comprising the ring system. The C-Ring (dark gray area) seems to blend into the brighter B-Ring as the concentric features radiate out from the planet. The dark spoke-like features seen in images taken during the approach to Saturn now appear as bright streaks, indicating that they may be composed of small particles. 11/12/80 750,000 km (470,000 mi) Two narrow, braided rings in the F-Ring are evident in this view, as well as a broader, very diffuse component about 35 kilometers (20 miles) across. A totally unexpected discovery, the braided rings trace distinctly separate orbits intertwining each other. The “knots” may be local clumps of ring material or tiny moons. It is difficult to explain this complicated structure using only the gravitational forces known to be affecting the particles of this ring. It is possible that additional, electrostatic forces may also influence these particles. 11/8/80 7 million km (4.3 million mi) Brightness variations in the F-Ring may be due to clumping in the ring material. The features are seen at the top and again near the left edge of the ring in this image. The “gap” in the ring (left center) is not real but is the location of a reseau mark on the camera’s vidicon tube. These bright features in the F-Ring appear to move at the orbital rate of the ring particles and may be larger bodies or thicknesses in the rings. Saturn’s thirteenth and fourteenth satellites, which orbit on either side of the F-Ring, may act like “sheepdogs,” herding the F-Ring particles between them. Less than 100 kilometers (60 miles) wide, the F-Ring is located outside of the A-Ring. Satellite 14, discovered by Voyager 1, is seen just inside the F-Ring. |
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