WIRED Staff
Science

Slideshow: Saturn Moon Reveals Its Secrets

Data from the Cassini space probe's flyby of Phoebe give scientists hope for uncovering the mysteries of the solar system, including its origin. By Amit Asaravala.
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This graphic illustrates that despite Phoebe's bumpy, irregular topography, the moon has a fairly round shape. A digitally rendered shape model of Phoebe was constructed using Cassini imaging data obtained before and after the spacecraft's close flyby of the Saturnian moon on June 11, 2004. The four views of the model are each separated by a 90-degree rotation; the upper left is centered at 0 degrees west longitude. The others show regions of the moon centered at 90, 180 and 270 degrees west longitude, as labeled. The coloring of the models corresponds to the height of Phoebe's surface, relative to the lowest point -- a range of about 16 kilometers (10 miles) -- going from blue (low) to red (high).Courtesy of NASA/JPL/University of Colorado

See related story: Saturn Moon Reveals Its Secrets

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Bright streaks on the rim of the large crater in Phoebe's north may have been revealed by the collapse of overlying darker material from the crater wall. The large crater below and to the right of the center shows evidence of layered deposits of alternating bright and dark material. Hints of Phoebe's irregular topography can be seen peeking out from the shadows near the lower left and upper left of the image. These are physical features -- possibly crater rims or mountain peaks -- that are just being hit by the first light of sunrise on Phoebe.

Courtesy of NASA/JPL/University of Colorado
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On the right, the ultraviolet image of Saturn's moon Phoebe, taken from a distance of 31,000 kilometers (about 19,263 miles) shows an irregular surface and bright crater region (white area). The bright areas indicate water frost on Phoebe's surface. The image was taken by Cassini's ultraviolet imaging spectrograph during the spacecraft's closest approach to Phoebe, on June 11, 2004. The large crater shows clearly in the image on the left.

Courtesy of NASA/JPL/University of Colorado
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Cassini continues its vigil as Saturn's atmosphere churns and morphs through time. Four large dark spots, or storms, form a symmetrical pattern in the mid-southern latitudes as these features squeeze past each other. Further observations will show whether these storms merge or spawn new spots of their own. North of the features, some latitudinal bands exhibit a bumpy or scalloped pattern, probably indicative of planet-scale wave motions in the atmosphere.

Courtesy of NASA/JPL/University of Colorado
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Images like this one, showing bright wispy streaks thought to be ice revealed by subsidence of crater walls, are leading to the view that Phoebe is an ice-rich body overlaid with a thin layer of dark material. Obvious down-slope motion of material along the walls of the major craters in this image is the cause for the bright streaks, which are overexposed here. Significant slumping has occurred along the crater wall at top left.

Courtesy of NASA/JPL/University of Colorado