With the official release (in the UK anyway) of the "Atlas of the Solar System" by myself and Cambridge Univ. Press this past week, I thought it high time to release some new goodies. Okay it is more views of the icy Saturnian satellites, but I do have several new Galilean satellite views ready to be posted when the book begins to appear on buyers desks. The views shown here are clips from three new movies of Rhea, Tethys, and Iapetus. Those of Rhea and Tethys feature distinctive impact craters. On Rhea we see what may be the youngest large crater in the Saturn system, Inktomi, while on Tethys, we fly over one of the largest impact basins in the Saturn system, Odysseus. Both are rather deep, but Inktomi is distinct for its extensive bright ray system radiating from the crater rim. These rays are diagnostic of very young impact craters. For Iapetus we fly over a broken section of the infamous and equally puzzling linear ridge that straddles the Iapetan equator. In this region, we see several 15-20 kilometer high peaks along the trace of the ridge in a region where large portions are missing.
Link to videos:
http://www.youtube.com/galsat400
INKTOMI - RHEA'S BRIGHT RAY CRATER
This perspective view features Inktomi, a prominent 48-kilometer-wide bright ray crater on the icy surface of Rhea, Saturn's second largest satellite. Inktomi is the youngest and most spectacular of Rhea's many large impact craters, and most likely formed within the last few million years. The Cassini spacecraft, in orbit around Saturn, observed this crater in September 2007 at high resolution, in color, and in stereo, providing one of the best color topographic maps of Saturn's icy satellites. These perspective views highlight the steep 6 to 7 kilometer high rim wall cliffs of Inktomi. Rolling hills on the floor of the crater are debris mounds formed when portions of the rim collapsed onto the crater floor. The blue color of the rim scarp (which is actually nearly white: color is exaggerated here for clarity) reveals the crustal composition of Rhea and indicates that larger ice grain sizes or a more pure ice composition may dominate below the surface. The surface beyond the rim has been covered and scarred by icy material ejected from within Inktomi, material that also forms the extensive system of bright rays radiating away from crater center. These perspective views are based on stereo topography derived from Cassini orbiter imaging data and are excerpted from a digital movie showing a hypothetical flight over Inktomi. Mosaic base is at a resolution of 40 meters per pixel. Image processing, stereo topography, and visualization were performed by Dr. Paul Schenk, Lunar and Planetary Institute, Houston.
NISHANU - ANCIENT CRATER OF RHEA
This perspective view of Nishanu, a large 120-kilometer-wide impact crater on Saturn's icy moon Rhea, illustrates the complexity of these ancient cratered surfaces. The steep 6 kilometer deep rimwall of this impact basin is easily identified by the wide bluish ring scarp (a portion of the bluish rimwall of a smaller impact crater is also visible at lower left). The blue color is actually nearly white and the color of the scene is exaggerated here for clarity. It may be due to the exposure of crustal ice with larger grain sizes or less rocky impurities beneath the darker redder surface. The bright patches at the top of the scene are icy material ejected from the nearby very young bright ray crater Inktomi. These perspective views are based on stereo topography derived from Cassini orbiter imaging data and are excerpted from a digital movie showing a hypothetical flight over Inktomi. Mosaic base is at a resolution of 40 meters per pixel. Image processing, stereo topography, and visualization were performed by Dr. Paul Schenk, Lunar and Planetary Institute, Houston.
TETHYS - ODYSSEUS IMPACT BASIN
The 420 kilometer diameter Odysseus impact basin dominates Saturn's icy moon Tethys. This view shows the eastern two-thirds of Odysseus. Odysseus is relatively young, perhaps only 1 billion years old. It is therefore well preserved. The 2 to 3 kilometers high rim ridge defines the outer edge of the basin. The total depth from rim to floor is 8 kilometers, making Odysseus one of the deepest impact features in the Solar System. A rugged central mountain complex (at center right) forms a crude topographic ring rising 3 to 5 kilometers above the basin floor, roughly half way up to the level of the surrounding crater rim. These perspective views are based on stereo topography derived from Cassini orbiter imaging data and are excerpted from a digital movie showing a hypothetical flight over Odysseus. Mosaic base is at a resolution of 450 meters per pixel. Image processing, stereo topography, and visualization were by Dr. Paul Schenk, Lunar and Planetary Institute, Houston.
EQUATORIAL MOUNTAINS OF IAPETUS
One of the many surprises of Saturn's icy moon Iapetus is the prominent topographic ridge that straddles the eauator like a walnut. This perspective view looks east along the length of the equatorial ridge and is based on stereo topography derived from Cassini orbiter imaging data. The Cassini orbiter acquired a strip of color and stereo images along this ridge in September 2007, near the boundary between the dark and bright hemispheres. This stark albedo contrast has been observed since the late 1600's and was famously described in Arthur C. Clarke's novel adaptation of "2001: A Space Odyssey." The origin of the ridge is unknown but Cassini's stereo data indicate the ridge at this site is broken into several sharp peaks 15 to 20 kilometers above the surrounding dark cratered plains. These are among the highest peaks in the Solar System. Patches of bright pure water ice can be seen flanking these dark peaks, which have the brightness of soot. The scene is ~350 kilometers across from top to bottom and is excerpted from a new movie showing a hypothetical flight over Iapetus. Mosaic base is at a resolution of 55 meters per pixel. Image processing, stereo topography, and visualization were completed by Dr. Paul Schenk, Lunar and Planetary Institute, Houston.
PEAKS OF IAPETUS
One of the many surprises of Saturn's icy moon Iapetus is the prominent topographic ridge that straddles the eauator like a walnut. The Cassini orbiter acquired a strip of color and stereo images along this ridge in September 2007, near the boundary between the dark and bright hemispheres. This stark albedo contrast has been observed since the late 1600's and was famously described in Arthur C. Clarke's novel adaptation of "2001: A Space Odyssey." The origin of the ridge is unknown but Cassini's stereo data indicate the ridge at this site is broken into several sharp peaks 15 to 20 kilometers above the surrounding dark cratered plains. These are among the highest peaks in the Solar System. This perspective view looks southeast toward one of these peaks and is based on stereo topography derived from Cassini orbiter imaging data. Patches of bright pure water ice can be seen flanking these dark peaks, which have the brightness of soot. The scene is ~70 kilometers across and is excerpted from a new movie showing a hypothetical flight over Iapetus. Mosaic base is at a resolution of 55 meters per pixel. Image processing, stereo topography, and visualization were performed by Dr. Paul Schenk, Lunar and Planetary Institute, Houston.
EQUATORIAL TOPOGRAPHY OF IAPETUS
The Cassini orbiter acquired a strip of color and stereo images along the equator of Saturn's icy moon Iapetus in September 2007, near the boundary between the dark and bright hemispheres. This view shows an area of the equator on the trailing hemisphere crossed by low ridges and fault scarps. The prominent equatorial ridge seen elsewhere is mostly missing in this scene and replaced by low ridges and fault scarps trending north-south. This perspective view looks south across the equator and is based on stereo topography derived from Cassini orbiter imaging data. Patches of bright pure water ice can be seen flanking some of the darker cratered slopes. The scene is ~100 kilometers across and is excerpted from a new movie showing a hypothetical flight over Iapetus. Mosaic base is at a resolution of 55 meters per pixel. Image processing, stereo topography, and visualization were performed by Dr. Paul Schenk, Lunar and Planetary Institute, Houston.
