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Ganymede dark terrain at hig
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Impact craters dominate the
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12/16/00
| Date |
12/16/00 |
| Description |
Impact craters dominate the surface down to the smallest features visible on the dark terrain of the Nicholson Regio region of Jupiter's moon Ganymede in this image taken by NASA's Galileo spacecraft. It is the highest resolution view ever obtained of Ganymede's dark terrain. Both the regional-scale image at the bottom and high- resolution image at the top were taken by Galileo during its May 20, 2000, flyby of Ganymede. The latter are the highest resolution images ever obtained of Ganymede's dark terrain, which makes up about one third of Ganymede's surface. Impact cratering is clearly the dominant mechanism of surface modification in this relatively ancient terrain, which is analogous to the cratered highlands of Earth's Moon. Small- scale craters seem to mimic larger-scale craters, as is apparent in the similarities between the high and medium resolution scenes. The bright spots are probably fresh ice-rich ejecta excavated by the most recent impact events. North is to the top of the images and the Sun illuminates the surface from the west. The medium-resolution image, centered at –15 degrees latitude and 337 degrees longitude, covers an area approximately 237 by 130 kilometers (147 by 81 miles) at a resolution of 125 meters (410 feet) per picture element. The high-resolution image is at 28 meters (92 feet) per picture element. This image and other images and data received from Galileo are posted on the Galileo mission home page at http://www.jpl.nasa.gov/galileo . Background information and educational context for the images can be found at http://www.jpl.nasa.gov/galileo/sepo . The Jet Propulsion Laboratory, a division of the California Institute of Technology, in Pasadena, manages the Galileo mission for NASA's Office of Space Science, Washington, D.C. The images were produced by Arizona State University, Tempe, and Brown University, Providence, R.I.. Their websites are at http://europa.la.asu.edu/index.html and http://www.planetary.brown.edu/ . # # # # # |
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Regional view of bright and
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This view of the Nicholson R
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12/16/00
| Date |
12/16/00 |
| Description |
This view of the Nicholson Regio/Arbela Sulcus region on Jupiter's moon Ganymede, taken by NASA's Galileo spacecraft, shows the stark contrast between the smooth bright terrain and the surrounding highly fractured dark terrain. This observation was designed in part to distinguish between different models for how Arbela Sulcus and other groove lanes on Ganymede were formed. The volcanic model suggests that a relatively clean, water-rich lava filled a tectonic depression, then cooled to create a smooth surface. Tectonic models suggest that focused faulting and deformation of older dark terrain destroyed the pre-existing texture, which was brightened by exposure of underlying, clean ice. Analysis of these photos suggests a third and unexpected possibility: Arbela Sulcus may be similar to some bands on another of Jupiter's moons, Europa, formed by tectonic crustal spreading and renewal. North is to the upper left of the picture and the Sun illuminates the surface from the west. The image, centered at – 14 degrees latitude and 347 degrees longitude, covers an area approximately 258 by 116 kilometers (160 by 72 miles). The resolution is 133 meters (436 feet) per picture element. The images were taken on May 20, 2000, at a range of 13,100 kilometers (8,140 miles). This image and other images and data received from Galileo are posted on the Galileo mission home page at http://www.jpl.nasa.gov/galileo . Background information and educational context for the images can be found at http://www.jpl.nasa.gov/galileo/sepo . The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the Galileo mission for NASA's Office of Space Science, Washington, D.C. This image was produced by DLR (German Aerospace Center), Berlin, and Brown University, Providence, R.I., http://solarsystem.dlr.de/ and http://www.planetary.brown.edu/ . # # # # # |
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Ganymede feature resembling
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This frame compares a high-r
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12/16/00
| Date |
12/16/00 |
| Description |
This frame compares a high-resolution view of Arbela Sulcus on Jupiter's moon Ganymede (top) with the gray band Thynia Linea on another Jovian moon, Europa (bottom), shown to the same scale. Both images are from NASA's Galileo spacecraft. Arbela Sulcus is one of the smoothest lanes of bright terrain identified on Ganymede, but subtle striations are apparent here along its length. This section of Arbela contrasts markedly from highly fractured terrain to its west and dark terrain to its east. On Europa, gray bands such as Thynia Linea have formed by tectonic crustal spreading and renewal. Such bands have sliced through and completely separated pre-existing features in the surrounding bright, ridged plains. The younger prominent double ridge Delphi Flexus cuts across Thynia Linea. The scarcity of craters on Europa attests to the relative youth of its surface compared to Ganymede's. Unusual for Ganymede, it is possible that Arbela Sulcus has formed by complete separation of Ganymede's icy crust, like bands on Europa. Tests of this idea come from detailed comparisons of their internal shapes and the relationships to the surrounding structures. In the Ganymede image, north is to the top of the picture and the Sun illuminates the surface from the west. The image, centered at -15 degrees latitude and 347 degrees longitude, covers an area approximately 34 by 26 kilometers (21 by 16 miles). The resolution is 34 meters (112 feet) per picture element. The image was taken on May 20, 2000, at a range of 3,370 kilometers (2,094 miles). In the Europa image, north is to the upper-right of the picture and the Sun illuminates the surface from the northwest. The image, centered at -66 degrees latitude and 161 degrees longitude, covers an area approximately 44 by 46 kilometers (27 by 29 miles). The resolution is 45 meters (147 feet) per picture element. The image was taken on September 26, 1998, at a range of 3,817 kilometers (2,371 miles). This image and other images and data received from Galileo are posted on the Galileo mission home page at http://www.jpl.nasa.gov/galileo . Background information and educational context for the images can be found at http://www.jpl.nasa.gov/galileo/sepo . The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the Galileo mission for NASA's Office of Space Science, Washington, D.C. This image was produced by DLR (German Aerospace Center), Berlin, and Brown University, Providence, R.I., http://solarsystem.dlr.de/ and http://www.planetary.brown.edu/ . # # # # # |
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Comparison of Ganymede and E
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This image, taken by NASA's
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12/16/00
| Date |
12/16/00 |
| Description |
This image, taken by NASA's Galileo spacecraft, shows a same-scale comparison between Arbela Sulcus on Jupiter's moon Ganymede (left) and an unnamed band on another Jovian moon, Europa (right). Arbela Sulcus is one of the smoothest lanes of bright terrain identified on Ganymede, and shows very subtle striations along its length. Arbela contrasts markedly from the surrounding heavily cratered dark terrain. On Europa, dark bands have formed by tectonic crustal spreading and renewal. Bands have sliced through and completely separated pre-existing features in the surrounding bright ridged plains. The scarcity of craters on Europa illustrates the relative youth of its surface compared to Ganymede's. Unusual for Ganymede, it is possible that Arbela Sulcus has formed by complete separation of Ganymede's icy crust, like bands on Europa. Prominent fractures on either side of Arbela appear to have been offset by about 65 kilometers (about 40 miles) along the length of the area of furrows and ridges, suggesting that strike-slip faulting was important in the formation of Arbela Sulcus. In the Ganymede image, north is to the upper left of the picture and the Sun illuminates the surface from the west. The image, centered at -14 degrees latitude and 347 degrees longitude, covers an area approximately 258 by 116 kilometers (160 by 72 miles.) The resolution is 133 meters (436 feet) per picture element. The images were taken on May 20, 2000, at a range of 13,100 kilometers (8,100 miles). In the Europa image, north is to the left of the picture and the Sun illuminates the surface from the east. The image, centered at -7 degrees latitude and 236 degrees longitude, covers an area approximately 275 by 424 kilometers (171 by 263 miles.) The resolution is 220 meters (about 720 feet) per picture element (re-sampled here to 133 meters, or 436 feet). The images were taken on Nov. 6, 1997, at a range of 21,500 kilometers (13,360 miles). The Jet Propulsion Laboratory, Pasadena, Calif., manages the Galileo mission for NASA's Office of Space Science, Washington, DC. JPL is a division of the California Institute of Technology in Pasadena. Images and data received from Galileo are posted on the Galileo mission home page at http://www.jpl.nasa.gov/galileo. Background information and educational context for the images can be found at http://www.jpl.nasa.gov/galileo/sepo . Images were produced by Brown University, Providence, R.I., http://www.planetary.brown.edu/, DLR (German Aerospace Center) Berlin, http://solarsystem.dlr.de , and University of Arizona, Tempe, http://www.lpl.arizona.edu/. # # # # # |
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Bright-Dark terrain boundary
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The boundary between the bri
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12/16/00
| Date |
12/16/00 |
| Description |
The boundary between the bright terrain of Harpagia Sulcus (right) and dark terrain of Nicholson Regio (left) areas of Jupiter's moon Ganymede springs out when viewed through red/blue 3-D glasses, in this image taken by NASA's Galileo spacecraft as it flew by Ganymede on May 20, 2000. Details of the rough, ancient, heavily cratered dark terrain of Nicholson Regio are in stark contrast to the very smooth, bright, young terrain of Harpagia Sulcus. In the center lies the transition to the boundary between these two regions, providing evidence that extensional faulting marks the boundary. A series of steep slopes deform the dark terrain close to the boundary. In the bright terrain, a deep trough and flanking ridge delimit the boundary. North is to the top of the picture. The Sun illuminates the surface from the left. The imaged region, centered at –14 degrees latitude and 319 degrees longitude, covers an area approximately 25 by 10 kilometers (15.5 by 6 miles.) The resolutions of the two data sets are 20 meters (66 feet) per picture element and 121 meters (397 feet) per picture element. The higher resolution images were taken at a range of 2,000 kilometers (about 1,200 miles). The Jet Propulsion Laboratory, Pasadena, Calif., manages the Galileo mission for NASA's Office of Space Science, Washington, D.C. JPL is a division of the California Institute of Technology in Pasadena. This image and other images and data received from Galileo are posted on the Galileo mission home page at http://www.jpl.nasa.gov/galileo . The image was produced by the German Aerospace Center (DLR), http://solarsystem.dlr.de and Brown University, http://www.planetary.brown.edu/ . Background information and educational context for the images can be found at http://www.jpl.nasa.gov/galileo/sepo . # # # # # |
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Bright-dark boundary and top
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These images, taken by NASA'
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12/16/00
| Date |
12/16/00 |
| Description |
These images, taken by NASA's Galileo spacecraft on its May 20, 2000, flyby of Jupiter's moon Ganymede, illustrate the boundary and different elevations between the dark, ancient terrain of Nicholson Regio (left) and bright, younger terrain of Harpagia Sulcus (right.) The bottom image is a wide view of the boundary, and the top image is an enlargement of the colorized strip. An important goal of Galileo's Ganymede encounter was to understand the nature of the boundary between ancient, dark terrain and younger, bright terrain. The camera was aimed at the boundary to obtain both very high-resolution images (top) and medium-resolution context images (bottom). Color-coded elevations are indicated relative to the average elevation of the sampled area, with high elevation marked in red, and low in blue. Combining the two image mosaics allows scientists to derive a detailed description of the region from the overlap. The data shows that there are approximately 200 meters (about 650 feet) of topographic relief within the bright terrain here, and a deep depression marks the boundary between bright and dark terrains. North is to the top of the pictures. The Sun illuminates the surface from the left. The larger image, centered at –14 degrees latitude and 319 degrees longitude, covers an area approximately 213 by 97 kilometers (132 by 60 miles.) The resolution of the high-resolution image is 20 meters (about 65 feet) per picture element, and the context image is at 121 meters (397 feet) per picture element. The higher resolution image was taken at a range of 2000 kilometers (over 1,200 miles). The Jet Propulsion Laboratory, Pasadena, Calif., manages the Galileo mission for NASA's Office of Space Science, Washington, D.C. JPL is a division of the California Institute of Technology in Pasadena. This image and other images and data received from Galileo are posted on the Galileo mission home page at http://www.jpl.nasa.gov/galileo . The images were produced by the German Aerospace Center (DLR) http://solarsystem.dlr.de/ , and Brown University, http://www.planetary.brown.edu/ . Background information and educational context for the images can be found at http://www.jpl.nasa.gov/galileo/sepo . # # # # # |
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Caldera-like depression on G
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The shallow, scalloped depre
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12/16/00
| Date |
12/16/00 |
| Description |
The shallow, scalloped depression in the center of this picture from NASA's Galileo spacecraft is a caldera-like feature 5 to 20 kilometers (3 to 12 miles) wide on Jupiter's largest moon, Ganymede. Calderas are surface depressions formed by collapse above a subsurface concentration of molten material. Some shallow depressions in bright, smooth areas of Ganymede have some overall similarities to calderas on Earth and on Jupiter's moon Io. On Ganymede, caldera-like depressions may serve as sources of bright, volcanic flows of liquid water and slush, an idea supported by a Ganymede photo obtained by Galileo during its seventh orbit and available at http://photojournal.jpl.nasa.gov/cgi- bin/PIAGenCatalogPage.pl?PIA01614 . In the more recent image here, from Galileo's 28th orbit, a tall scarp marks the western boundary of a caldera-like feature. The western scarp is aligned similarly to older tectonic grooves visible in the image, suggesting the feature has collapsed along older lines of weakness. The interior is mottled in appearance, yet smooth compared to most of Ganymede's bright terrain seen at high resolution. The eastern boundary of the caldera-like feature is cut by younger, grooved terrain. Small impact craters pepper the scene, but the lack of a raised rim argues against an impact origin for the caldera-like feature itself. Instead, water-rich icy lava may have once flowed out of it toward the east. If so, later tectonism could have erased any telltale evidence of volcanic flow fronts. Direct evidence for icy volcanism on Ganymede continues to be elusive. North is to the top of the picture and the Sun illuminates the surface from the left. The image, centered at -24 degrees latitude and 318 degrees longitude, covers an area approximately 162 by 119 kilometers (101 by 74 miles). The resolution is 43 meters (141 feet) per picture element. This image and other images and data received from Galileo are posted on the Galileo mission home page at http://www.jpl.nasa.gov/galileo . Background information and educational context for the images can be found at http://www.jpl.nasa.gov/galileo/sepo . The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the Galileo mission for NASA's Office of Space Science, Washington, D.C. This image was produced by Brown University, Providence, R.I., http://www.planetary.brown.edu/ . # # # # # |
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Not-so-smooth bright terrain
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The highest-resolution image
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12/16/00
| Date |
12/16/00 |
| Description |
The highest-resolution images ever obtained of Jupiter's moon Ganymede show that even smooth-looking terrain has been deformed at a fine scale. The high-resolution image taken of the bright Harpagia Sulcus area by NASA's Galileo spacecraft during a May 20, 2000, flyby of Ganymede shows features as small as 16 meters (52 feet). This area was selected for a closer look because, in images taken by NASA's Voyager spacecraft about 20 years earlier, it looked as flat as a hockey rink. It appears smooth even in a medium-resolution Galileo image (at 116 meters or 380 feet per pixel) that is superimposed over a Voyager image in the top portion of this frame. But the closeup shot revealed that, instead of a hockey rink, the area has ups and downs that would be challenging for a cross-country skier. North is to the top of the picture and the Sun illuminates the surface from the left. The medium-resolution image mosaic is centered at -16 degrees latitude and 310 degrees longitude, and covers an area approximately 282 by 144 kilometers (175 by 89 miles). This image and other images and data received from Galileo are posted on the Galileo mission home page at http://www.jpl.nasa.gov/galileo . Background information and educational context for the images can be found at http://www.jpl.nasa.gov/galileo/sepo . The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the Galileo mission for NASA's Office of Space Science, Washington, D.C. This image was produced by DLR (German Aerospace Center), Berlin, and Brown University, Providence, R.I., http://solarsystem.dlr.de/ and http://www.planetary.brown.edu/ . # # # # # |
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Iapetus: A View from the Top
| Description |
Iapetus: A View from the Top |
| Full Description |
This oblique view of Saturn's moon Iapetus from high latitude shows how the dark, heavily cratered terrain of Cassini Regio transitions to a bright, icy terrain at high latitudes. In this mosaic of two high resolution images taken during Cassini's New Year's Eve 2004 flyby of Iapetus, the direction toward the north pole is approximately 15 degrees below the horizontal on the right. At the equator terrains are uniformly covered with a dark mantle of material that has a reflectivity of about 4 percent. At latitudes toward the pole of about 40 degrees, the dark deposits become patchy and diffuse as the surface transitions to a much brighter, icy terrain near the pole. The brightest icy materials exhibit visual reflectivity over 60 percent. Superimposed on the bright terrain is a subtle, ghostly pattern of crudely parallel, north-south trending wispy streaks. The streaks, which were discovered during this flyby of Iapetus, are typically a few kilometers wide and sometimes tens of kilometers long. Their appearance and orientation may be connected with the emplacement of dark materials that cover Cassini Regio. The dark materials might represent the gradual accumulation of dark debris falling from space, or alternatively, may represent fallout from plume-style eruptions that may have accompanied the formation of Iapetus's enigmatic equatorial ridge (see PIA 06166). Also seen in this mosaic are conspicuous, north-facing bright crater walls. An example can be seen in the upper left where the bright, 4-kilometer-high (2.5 miles) walls of a 70 kilometer (44 mile) central-peak crater lies. The bright crater walls are often higher in brightness than the corresponding south-facing walls of the same crater. They are vaguely reminiscent of bright north-facing crater walls that were discovered by NASA's Voyager and Galileo spacecraft in craters near the poles of the Jovian satellites Callisto and Ganymede. In the case of the Jovian satellites, cold-trapping of frosts on north-facing slopes and sublimation of ices from south-facing slopes are thought to produce the north-south asymmetries in crater wall brightness. However, the occurrence of some young-appearing craters on Iapetus that have bright north-facing and dark south-facing slopes, and the pattern of streaks near the north pole of Iapetus suggests that another mechanism may be responsible for the crater wall brightness asymmetries on Iapetus. One possibility is that the south-facing slopes may be stained by the same process that emplaced the low brightness coating throughout the region. In this case, the north-pointing scarps might be bright because they face away and are shielded from the putative falling spray of dark materials. Bright south-facing slopes would exist primarily on young craters that have not been exposed to the darkening agent long enough to be stained. The image was obtained in visible light with the Cassini spacecraft narrow angle camera on Dec. 31, 2004, at a distance of, about 123,370 kilometers (76,658 miles) from Iapetus and at a Sun-Iapetus-spacecraft, or phase, angle of 93 degrees. Resolution achieved in the original image was 732 meters (2,401 feet) per pixel. The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the mission for NASA's Science Mission Directorate, Washington, D.C. The Cassini orbiter and its two onboard cameras were designed, developed and assembled at JPL. The imaging team is based at the Space Science Institute, Boulder, Colo. For more information about the Cassini-Huygens mission visit http://saturn.jpl.nasa.gov . For images visit the Cassini imaging team home page http://ciclops.org . Credit: NASA/JPL/Space Science Institute |
| Date |
January 7, 2005 |
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Transition on Enceladus
| Description |
Transition on Enceladus |
| Full Description |
This view of Saturn's moon Enceladus shows an area that has undergone a very intriguing -- and in places puzzling -- sequence of events. The craters here are subdued, as seen elsewhere on Enceladus, and most, but not all, are older than the fractures. Fracturing has occurred at a wide variety of scales, from the wide rift running through the center of the image to much narrower sets of shorter fractures that crosscut the craters (and each other) to the left. The image has been rotated so that north on Enceladus is up. This region is a transition from cratered to wrinkled terrain. Westward (left) of the central rift that divides the two regions are relatively parallel grooves and ridges that are reminiscent of terrain on Jupiter's large moon Ganymede. Very few craters are seen in this area of Enceladus. Eastward (right) of the large rift the terrain becomes more cratered, although the craters are quite degraded (meaning soft and shallow in appearance). A prominent fracture runs north-south to the center of the image, then turns sharply to the southwest, cutting across cratered terrain, the large rift, and the grooved terrain. This behavior signifies that it is one of the youngest features in this image. The image was taken in visible light with the narrow angle camera from a distance of about 14,000 kilometers (8,800 miles) and from Enceladus and at a Sun-Enceladus-spacecraft, or phase, angle of 44 degrees. Pixel scale in the image is about 85 meters (280 feet) per pixel. A stereo anaglyph version of the scene is also available (see Transition on Enceladus (3-D)). The images have been contrast-enhanced to aid visibility. The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the mission for NASA's Science Mission Directorate, Washington, D.C. The Cassini orbiter and its two onboard cameras were designed, developed and assembled at JPL. The imaging team is based at the Space Science Institute, Boulder, Colo. For more information about the Cassini-Huygens mission visit http://saturn.jpl.nasa.gov . For additional images visit the Cassini imaging team homepage http://ciclops.org . *Credit:* NASA/JPL/Space Science Institute |
| Date |
March 24, 2005 |
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Transition on Enceladus (3-D
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| Description |
Transition on Enceladus (3-D) |
| Full Description |
This stereo anaglyph of Saturn's moon Enceladus shows an area that has undergone a very intriguing -- and in places puzzling -- sequence of events. The craters here are subdued, as seen elsewhere on Enceladus, and most, but not all, are older than the fractures. Fracturing has occurred at a wide variety of scales, from the wide rift running through the center of the image to much narrower sets of shorter fractures that crosscut the craters (and each other) to the left. The anaglyph has been rotated so that north on Enceladus is up. This region is a transition from cratered to wrinkled terrain. Westward (left) of the central rift that divides the two regions are relatively parallel grooves and ridges that are reminiscent of terrain on Jupiter's large moon Ganymede. Very few craters are seen in this area of Enceladus. Eastward (right) of the large rift the terrain becomes more cratered, although the craters are quite degraded (meaning soft and shallow in appearance). A prominent fracture runs north-south to the center of the image, then turns sharply to the southwest, cutting across cratered terrain, the large rift, and the grooved terrain. This behavior signifies that it is one of the youngest features in this image. The images for this anaglyph were taken in visible light with Cassini's narrow-angle camera, at distances from Enceladus ranging from about 25,700 kilometers (16,000 miles, red-colored image) to 14,000 kilometers (8,800 miles, blue-colored image) and at a Sun-Enceladus-spacecraft, or phase, angle ranging from 46 to 44 degrees. Pixel scale in the red image was 150 meters (490 feet) per pixel. Scale in the blue image was 85 meters (280 feet) per pixel. A separate, non-stereo version of the scene, showing only the red image, is also available (see Transition on Enceladus (3-D)). The images have been contrast-enhanced to aid visibility. The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the mission for NASA's Science Mission Directorate, Washington, D.C. The Cassini orbiter and its two onboard cameras were designed, developed and assembled at JPL. The imaging team is based at the Space Science Institute, Boulder, Colo. For more information about the Cassini-Huygens mission visit http://saturn.jpl.nasa.gov . For additional images visit the Cassini imaging team homepage http://ciclops.org . *Credit:* NASA/JPL/Space Science Institute |
| Date |
March 24, 2005 |
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The Face of Phoebe
| Description |
The Face of Phoebe |
| Full Description |
Phoebe's true nature is revealed in startling clarity in this mosaic of two images taken during Cassini's flyby on June 11, 2004. The image shows evidence for the emerging view that Phoebe may be an ice-rich body coated with a thin layer of dark material. Small bright craters in the image are probably fairly young features. This phenomenon has been observed on other icy satellites, such as Ganymede at Jupiter. When impactors slammed into the surface of Phoebe, the collisions excavated fresh, bright material -- probably ice -- underlying the surface layer. Further evidence for this can be seen on some crater walls where the darker material appears to have slid downwards, exposing more light-colored material. Some areas of the image that are particularly bright - especially near lower right - are over-exposed. An accurate determination of Phoebe's density - a forthcoming result from the flyby - will help Cassini mission scientists understand how much of the little moon is comprised of ices. This spectacular view was obtained at a phase, or Sun-Phoebe-spacecraft, angle of 84 degrees, and from a distance of approximately 32,500 kilometers (20,200 miles). The image scale is approximately 190 meters (624 feet) per pixel. No enhancement was performed on this image. The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the Cassini-Huygens mission for NASA's Office of Space Science, Washington, D.C. The Cassini orbiter and its two onboard cameras were designed, developed and assembled at JPL. The imaging team is based at the Space Science Institute, Boulder, Colo. For more information about the Cassini-Huygens mission visit, http://saturn.jpl.nasa.gov and the Cassini imaging team home page, http://ciclops.org . Image Credit: NASA/JPL/Space Science Institute |
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| Description |
Here on the Gallery page you can find the very latest images, videos and products from the Cassini-Huygens mission to Saturn, including the spectacular launch, spacecraft assembly and the exciting trip to Saturn. |
| Full Description |
Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, Calif., manages the Cassini mission for NASA's Office of Space Science, Washington, D.C. Credit: NASA/JPL/University of Arizona (PIA02826) For higher resolution, click here., These two images, taken by NASA's Cassini spacecraft, show Jupiter in a near-infrared wavelength, and catch Europa, one of Jupiter's largest moons, at different phases. Cassini's narrow-angle camera took both images, the upper one from a distance of 69.9 million kilometers (43.4 million miles) on Oct. 17, 2000, and the lower one from a distance of 65.1 million kilometers (40.4 million miles) on Oct. 22, 2000. Both were taken at a wavelength of 727 nanometers, which is in the near-infrared region of the electromagnetic spectrum. The camera's 727-nanometer filter accepts only a narrow spectral range centered on a relatively strong absorption feature due to methane gas. In this spectral region, the amount of light reflected by Jupiter's clouds is only half that reflected in a nearby spectral region outside the methane band. The features that are brightest in these images are the highest and thickest clouds, such as the Great Red Spot and the band of clouds girding the equator, as these scatter sunlight back to space before it has a chance to be absorbed by the methane gas in the atmosphere. This stratigraphic effect can be seen even more prominently in an image released on Oct. 23, 2000, taken in the stronger methane band at 889 nanometers, in which the only bright features are the highest hazes over the equator, the poles and the Great Red Spot. By comparing images taken in the 727 nanometer filter with others taken at 889 nanometers and at a weaker methane band at 619 nanometers, researchers will probe the heights and thickness of clouds in Jupiter's atmosphere. Europa, a satellite of Jupiter about the size of Earth's Moon, is visible to the left of Jupiter in the upper image, and in front of the planet in the lower image. Another of Jupiter's Galilean satellites, Ganymede, which is larger than the planet Mercury, is to the right in the upper image, with brightness variations visible across its surface. In the upper image, Europa is caught entering Jupiter's shadow, and hence appears as a bright crescent, in the lower image, it is seen about one-and-a-half orbits later, in transit across the face of the planet. Because there is neither methane nor any strong absorber in this spectral region on the surface of Europa, it appears strikingly white and bright compared to Jupiter. Imaging observations of the moons Europa, Io and Ganymede entering and passing through Jupiter's shadow are planned for the two-week period surrounding Cassini's closest approach on Dec. 30, 2000. The purpose of these eclipse observations is to detect and measure the variability of emissions that arise from the interaction of the satellites' tenuous atmospheres with the charged particles trapped in Jupiter's magnetic field. At the times these images were taken, Cassini was about 3.3 degrees above Jupiter's equatorial plane, and the Sun-Jupiter-spacecraft angle was about 20 degrees. Cassini is a cooperative project of NASA, the European Space Agency and the Italian |
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The Face of Phoebe
| title |
The Face of Phoebe |
| date |
06.11.2004 |
| description |
Phoebe's true nature is revealed in startling clarity in this mosaic of two images taken during Cassini's flyby on June 11, 2004. The image shows evidence for the emerging view that Phoebe may be an ice-rich body coated with a thin layer of dark material. Small bright craters in the image are probably fairly young features. This phenomenon has been observed on other icy satellites, such as Ganymede at Jupiter. When impactors slammed into the surface of Phoebe, the collisions excavated fresh, bright material -- probably ice -- underlying the surface layer. Further evidence for this can be seen on some crater walls where the darker material appears to have slid downwards, exposing more light-colored material. Some areas of the image that are particularly bright - especially near lower right - are over-exposed. An accurate determination of Phoebe's density -- a forthcoming result from the flyby -- will help Cassini mission scientists understand how much of the little moon is comprised of ices. This spectacular view was obtained at a phase, or Sun-Phoebe-spacecraft, angle of 84 degrees, and from a distance of approximately 32,500 kilometers (20,200 miles). The image scale is approximately 190 meters (624 feet) per pixel. No enhancement was performed on this image. The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the Cassini-Huygens mission for NASA's Office of Space Science, Washington, D.C. The Cassini orbiter and its two onboard cameras, were designed, developed and assembled at JPL. The imaging team is based at the Space Science Institute, Boulder, Colo. For more information, about the Cassini-Huygens mission visit, http://saturn.jpl.nasa.gov [ http://saturn.jpl.nasa.gov/ ] and the Cassini imaging team home page, http://ciclops.org [ http://ciclops.org/ ]. Image Credit: NASA/JPL/Space Science Institute |
|
Ganymede's Nergal Crater
| title |
Ganymede's Nergal Crater |
| date |
09.06.1996 |
| description |
Two impact craters surrounded by an unusual ejecta blanket dominate this high-resolution image of the surface of Jupiter's moon Ganymede. NASA's Galileo spacecraft photographed this region as it passed Ganymede during its second orbit through the jovian system. North is to the top of the picture, and the Sun illuminates the surface from the southeast. Nergal, the larger crater, is about 8 kilometers in diameter, while the smaller (unnamed) crater to its west is 3 kilometers across. The craters are situated in a region of bright grooved terrain named Byblus Sulcus, located in the northern part of Marius Regio at 390N latitude and 2010W longitude. The distinctive ejecta blanket that surrounds them is darker nearer the craters and brighter further away. The inner region of the ejecta is characterized by a lobate appearance indicative of the flow of a liquid (or slushy) substance over the surface. The flow was probably icy surface material melted by the energy released during the impact that formed the crater. The picture covers an area about 48 by 34 kilometers across at a resolution of 86 meters per picture element. The image was taken on September 6, 1996, by the Solid-State Imaging System onboard the Galileo spacecraft. *Image Credit*: Brown University |
|
Ganymede's Khensu Crater
| title |
Ganymede's Khensu Crater |
| date |
09.06.1996 |
| description |
The dark-floored crater Khensu is the target of this image of Ganymede. The Solid-State Imaging System onboard the Galileo spacecraft imaged this region as it passed Ganymede during its second orbit through the jovian system. Khensu is located at 20N latitude and 1530W longitude in a region of bright terrain known as Uruk Sulcus, and is about 13 kilometers in diameter. Like some other craters on Ganymede, it possesses an unusually dark floor and a bright ejecta blanket. The dark component may be residual material from the impactor that formed the crater. Another possibility is that the impactor may have punched through the bright surface to reveal a dark layer beneath. Another large crater named El is partly visible in the top righthand corner of the image. This crater is 54 kilometers in diameter and has a small "pit" in its center. Craters with such a "central pit" are common across Ganymede and are especially intriguing since they may reveal secrets about the structure of the satellite's shallow subsurface. North is to the upper left of the picture, and the Sun illuminates the surface from nearly overhead. The image covers an area about 100 by 86 kilometers across at a resolution of 111 meters per picture element. The image was taken on September 6, 1996, by the Solid-State Imaging System onboard the Galileo spacecraft. *Image Credit*: Brown University |
|
Osiris Crater
| title |
Osiris Crater |
| description |
View of the bright rayed crater Osiris (40 S, 161 W) on Ganymede. North is to the bottom of the picture and the sun illuminates the surface from the left. The finest details that can be discerned in this picture are about 6.7 km across. The time is 8:45:09 UT on June 26, 1996. *Image Credit*: NASA |
|
Ganymede's Northern Limb
| title |
Ganymede's Northern Limb |
| description |
View of the Northern limb region on Ganymede showing the Galileo Regio region. North is to the bottom of the picture and the sun illuminates the surface from the left. The finest details that can be discerned in this picture are about 6.7 km across. The time is 8:45:09 UT on June 26, 1996. *Image Credit*: NASA |
|
Ganymede's Northern Terminat
…
| title |
Ganymede's Northern Terminator |
| description |
View of the Northern terminator region on Ganymede showing the Uruk Sulcus region. North is to the bottom of the picture and the sun illuminates the surface from the left. The finest details that can be discerned in this picture are about 6.7 km across. The time is 8:45:09 UT on June 26, 1996. *Image Credit*: NASA |
|
Ganymede's Bright Limb
| title |
Ganymede's Bright Limb |
| description |
View of the bright limb of Ganymede showing a field of bright rayed craters in the satellites equatorial region and southern hemisphere. North is to the bottom of the picture and the sun illuminates the surface from the left. The finest details that can be discerned in this picture are about 6.7 kilometers across. The Universal Time is 8:45:09 UT on June 26, 1996. *Image Credit*: NASA |
|
Galileo Regio's Furrowed Reg
…
| title |
Galileo Regio's Furrowed Region |
| description |
View of the Galileo Regio region on Ganymede showing fine details of the Galileo image fit into the larger scale, but much lower resolution view of the region taken 17 years earlier by Voyager. The broad curved furrow patterns are characteristic of the darker regions of this moon. North is to the top of the picture and the sun illuminates the surface from almost overhead in the Galileo picture. *Image Credit*: NASA |
|
Triple Eclipse
| title |
Triple Eclipse |
| description |
At first glance, Jupiter looks like it has a mild case of the measles. Five spots - one colored white, one blue, and three black are scattered across the upper half of the planet. Closer inspection by NASA's Hubble Space Telescope reveals that these spots are actually a rare alignment of three of Jupiter's largest moons - Io, Ganymede, and Callisto - across the planet's face. In this image, the telltale signatures of this alignment are the shadows [the three black circles] cast by the moons. Io's shadow is located just above center and to the left, Ganymede's on the planet's left edge, and Callisto's near the right edge. Only two of the moons, however, are visible in this image. Io is the white circle in the center of the image, and Ganymede is the blue circle at upper right. Callisto is out of the image and to the right. On Earth, we witness a solar eclipse when our Moon's shadow sweeps across our planet's face as it passes in front of our Sun. Jupiter, however, has four moons roughly the same size as Earth's Moon. The shadows of three of them occasionally sweep simultaneously across Jupiter. The image was taken March 28, 2004, with Hubble's Near Infrared Camera and Multi-Object Spectrometer. Seeing three shadows on Jupiter happens only about once or twice a decade. Why is this triple eclipse so unique? Io, Ganymede, and Callisto orbit Jupiter at different rates. Their shadows likewise cross Jupiter's face at different rates. For example, the outermost moon Callisto orbits the slowest of the three satellites. Callisto's shadow moves across the planet once for every 20 shadow crossings of Io. Add the crossing rate of Ganymede's shadow and the possibility of a triple eclipse becomes even more rare. Viewing the triple shadows in 2004 was even more special, because two of the moons were crossing Jupiter's face at the same time as the three shadows. Jupiter appears in pastel colors in this photo because the observation was taken in near-infrared light. Astronomers combined images taken in three near-infrared wavelengths to make this color image. The photo shows sunlight reflected from Jupiter's clouds. In the near infrared, methane gas in Jupiter's atmosphere limits the penetration of sunlight, which causes clouds to appear in different colors depending on their altitude. Studying clouds in near-infrared light is very useful for scientists studying the layers of clouds that make up Jupiter's atmosphere. Yellow colors indicate high clouds, red colors lower clouds, and blue colors even lower clouds in Jupiter's atmosphere. The green color near the poles comes from a thin haze very high in the atmosphere. Ganymede's blue color comes from the absorption of water ice on its surface at longer wavelengths. Io's white color is from light reflected off bright sulfur compounds on the satellite's surface. In viewing this rare alignment, astronomers also tested a new imaging technique. To increase the sharpness of the near-infrared camera images, astronomers, speeded up Hubble's tracking system so that Jupiter traveled through the telescope's field of view much faster than normal. This technique allowed scientists to take rapid-fire snapshots of the planet and its moons. They then combined the images into one single picture to show more details of the planet and its moons. *Image Credit*: NASA, ESA, and E. Karkoschka (University of Arizona) |
|
Hubble Spots Rare Triple Ecl
…
| Title |
Hubble Spots Rare Triple Eclipse on Jupiter |
|
Bright and Dark Slopes on Ga
…
| Title |
Bright and Dark Slopes on Ganymede |
| Description |
Ridges on the edge of Ganymede's north polar cap show bright east-facing slopes and dark west-facing slopes with troughs of darker material below the larger ridges. North is to the top. The bright slopes may be due to grain size differences, differences in composition between the original surface and the underlying material, frost deposition, or illumination effects. The large 2.4 kilometer (1.5 mile) diameter crater in this image shows frost deposits located on the north-facing rim slope, away from the sun. A smaller 675 meter (2200 foot) diameter crater in the center of the image is surrounded by a bright deposit which may be ejecta from the impact. Ejecta deposits such as this are uncommon for small craters on Ganymede. This image measures 18 by 19 kilometers (11 by 12 miles) and has a resolution of 45 meters (148 feet) per pixel. NASA's Galileo spacecraft obtained this image on September 6, 1996 during its second orbit around Jupiter. The Jet Propulsion Laboratory, Pasadena, CA manages the Galileo mission for NASA's Office of Space Science, Washington, DC. JPL is an operating division of California Institute of Technology (Caltech). This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo mission home page at URL http://galileo.jpl.nasa.gov. Background information and educational context for the images can be found at URL http://www.jpl.nasa.gov/galileo/sepo |
| Date |
03.27.1997 |
|
Saturn - high-resolution fil
…
| Title |
Saturn - high-resolution filtered image of Enceladus |
| Description |
This high-resolution filtered image of Enceladus was made from several images obtained Aug. 25 by Voyager 2 from a range of 119,000 kilometers (74,000 miles). It shows further surface detail on this Saturnian moon (also viewed in the accompanying release P-23955C/BW, S-2-50, imaged about the same time). Enceladus is seen to resemble Jupiter's Galilean satellite Ganymede, which is, however, about 10 times larger. Faintly visible here in "Saturnshine" is the hemisphere turned away from the sun. The Voyager project is managed for NASA by the Jet Propulsion Laboratory, Pasadena, Calif. |
| Date |
08.28.1981 |
|
Ganymede Galileo Regio High
…
| Title |
Ganymede Galileo Regio High Resolution Mosaic Shown in Context |
| Description |
Ancient impact craters shown in this image of Jupiter's moon Ganymede taken by NASA's Galileo spacecraft testify to the great age of the terrain, dating back several billion years. At the margin at the left, half of a 19-kilometer-diameter (12-mile) crater is visible. The dark and bright lines running from lower right to upper left and from top to bottom are deep furrows in the ancient crust of dirty water ice. The origin of the dark material is unknown, but it may be accumulated dark fragments from many meteorites that hit Ganymede. In this view, north is to the top, and the sun illuminates the surface from the lower left about 58 degrees above the horizon. The area shown is part of Ganymede's Galileo Regio region at latitude 18 degrees north, longitude 147 degrees west, it is about 46 by 64 kilometers (29 by 38 miles) in extent. Resolution is about 80 meters (262 feet) per pixel. The image was taken June 27 at a range of 7.563 kilometers (4,700 miles). The Jet Propulsion Laboratory manages the Galileo mission for NASA's Office of Space Science, Washington, DC. This image and other images and data received from Galileo are posted on the World Wide Web Galileo mission home page at http://galileo.jpl.nasa.gov. Background information and educational context for the images can be found at http:// www.jpl.nasa.gov/galileo/sepo. |
| Date |
02.27.1997 |
|
Ganymede Uruk Sulcus High Re
…
| Title |
Ganymede Uruk Sulcus High Resolution Mosaic Shown in Context |
| Description |
A mosaic of four Galileo high-resolution images of the Uruk Sulcus region of Jupiter's moon Ganymede (Latitude 11 N, Longitude: 170 W) is shown within the context of an image of the region taken by Voyager 2 in 1979, which in turn is shown within the context of a full-disk image of Ganymede. North is to the top of the picture, and the sun illuminates the surface from the lower left, nearly overhead. The area shown is about 120 by 110 kilometers (75 by 68 miles) in extent and the smallest features that can be discerned are 74 meters (243 feet) in size in the Galileo images and 1.3 kilometers (0.8 miles) in the Voyager data. The higher resolution Galileo images unveil the details of parallel ridges and troughs that are principal features in the brighter regions of Ganymede. High photometric activity (large light contrast at high spatial frequencies) of this ice-rich surface was such that the Galileo camera's hardware data compressor was pushed into truncating lines. The north-south running gap between the left and right halves of the mosaic is a result of line truncation from the normal 800 samples per line to about 540. The images were taken on 27 June, 1996 Universal Time at a range of 7,448 kilometers (4,628 miles) through the clear filter of the Galileo spacecraft's imaging system. Launched in October 1989, Galileo entered orbit around Jupiter on December 7, 1995. The spacecraft's mission is to conduct detailed studies of the giant planet, its largest moons and the Jovian magnetic environment. The Jet Propulsion Laboratory manages the Galileo mission for NASA's Office of Space Science, Washington, DC. This image and other images and data received from Galileo are posted on the World Wide Web Galileo mission home page at http://galileo.jpl.nasa.gov. Background information and educational context for the images can be found at http://www.jpl.nasa.gov/galileo/sepo. |
| Date |
02.26.1997 |
|
The Saturnian moon Enceladus
| Title |
The Saturnian moon Enceladus |
| Description |
This high-resolution image of Enceladus was made from several images obtained Aug. 25, 1981, by Voyager 2 from a range of 119,000 kilometers (74,000 miles). It shows further surface detail on this Saturnian moon. Enceladus is seen to resemble Jupiter's moon Ganymede, which is, however, about 10 times larger. Faintly visible here in light reflected from Saturn is the hemisphere turned away from the sun. The Voyager project is managed for NASA by the Jet Propulsion Laboratory, Pasadena, Calif. |
| Date |
01.13.1982 |
|
Europa, Ganymede, and Callis
…
PIA01656
Jupiter
Solid-State Imaging
| Title |
Europa, Ganymede, and Callisto: Surface comparison at high spatial resolution |
| Original Caption Released with Image |
Ganymede's youngest large craters would have been created only about one billion years ago. Europa's surface in this model should be very young, with this satellite being geologically quite active even today. The images were taken by the Solid State Imaging (SSI) system on NASA's Galileo spacecraft. They were processed by the Institute of Planetary Exploration of the German Aerospace Center (DLR) in Berlin, Germany, and scaled to a size of 150 meters per pixel (m/pixel). North is up in all images. The spatial resolution of the original data was 180 m/pixel for Europa and Ganymede and 90 m/pixel for Callisto. The Europa image was taken during Galileo's 6th orbit, the Ganymede image during the 7th, and the Callisto image during the 10th orbit. The Jet Propulsion Laboratory, Pasadena, CA manages the Galileo mission for NASA's Office of Space Science, Washington, DC. This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo mission home page at URL http://galileo.jpl.nasa.gov [ http://galileo.jpl.nasa.gov ]. Background information and educational context for the images can be found at URL http://www.jpl.nasa.gov/galileo/sepo [ http://www.jpl.nasa.gov/galileo/sepo ]., These images show a comparison of the surfaces of the three icy Galilean satellites, Europa, Ganymede, and Callisto, scaled to a common resolution of 150 meters per picture element (pixel). Despite the similar distance of 0.8 billion kilometers to the sun, their surfaces show dramatic differences. Callisto (with a diameter of 4817 kilometers) is "peppered" by impact craters, but is also covered by a dark material layer of so far unknown origin, as seen here in the region of the Asgard multi-ring basin. It appears that this layer erodes or covers small craters. Ganymede's landscape is also widely formed by impacts, but different from Callisto, much tectonic deformation can be observed in the Galileo images, such as these of Nicholson Regio. Ganymede, with a diameter of 5268 kilometers (one-and-a-half times larger than the Earth's moon), is the largest moon in the solar system. Contrary to Ganymede and Callisto, Europa (diameter 3121 kilometers) has a sparsely cratered surface, indicating that geologic activity took place more recently. Globally, ridged plains and the so-called "mottled terrain" are the main landforms. In the high-resolution image presented here showing the area around the Agave and Asterius dark lineaments, older ridges dominate the surface, while a small part of the younger mottled terrain is visible to the lower left of the image center. While all three moons are believed to be nearly as old as the solar system (4.5 billion years), the age of the surfaces, i.e. the time since the last major geologic activity took place, is still subject to debate. Without having surface samples in hand, the only method to roughly determine a planet's or satellite's geologic surface age is by crater counting. However, assumptions about the impactor fluxes must be made based on theoretical models and possible observations of candidate impactors such as asteroids and comets. Asteroids should have been very common in the early days of the solar system, but this source should have been largely exhausted by about 3.8 billion years before present. For comets, the impactor flux is believed to be rather constant throughout the whole lifetime of the solar system, meaning that the probability of an impact of a large comet is similar today as it was, say, four billion years ago. Assuming the asteroids have been the dominant bodies that impacted the Galilean satellites (which is believed to be the case on the Moon, the Earth, and other inner solar system bodies as well as within the asteroid belt itself), the surfaces of Ganymede and Callisto must be old, roughly four billion years. In this case, the Europan surface would by comparison have a mean age of one-hundred to several-hundred million years. Low-level geologic activity on Europa might be possible, but Ganymede and Callisto should be geologically dead. Assuming on the other hand that comets have been the main impactors in the Jovian system, Callisto's surface would still be determined to be old, but |
|
Iapetus: A View from the Top
PIA06170
Saturn
Imaging Science Subsystem -
…
| Title |
Iapetus: A View from the Top |
| Original Caption Released with Image |
). Also seen in this mosaic are conspicuous, north-facing bright crater walls. An example can be seen in the upper left where the bright, 4-kilometer-high (2.5 miles) walls of a 70 kilometer (44 mile) central-peak crater lies. The bright crater walls are often higher in brightness than the corresponding south-facing walls of the same crater. They are vaguely reminiscent of bright north-facing crater walls that were discovered by NASA's Voyager and Galileo spacecraft in craters near the poles of the Jovian satellites Callisto and Ganymede. In the case of the Jovian satellites, cold-trapping of frosts on north-facing slopes and sublimation of ices from south-facing slopes are thought to produce the north-south asymmetries in crater wall brightness. However, the occurrence of some young-appearing craters on Iapetus that have bright north-facing and dark south-facing slopes, and the pattern of streaks near the north pole of Iapetus suggests that another mechanism may be responsible for the crater wall brightness asymmetries on Iapetus. One possibility is that the south-facing slopes may be stained by the same process that emplaced the low brightness coating throughout the region. In this case, the north-pointing scarps might be bright because they face away and are shielded from the putative falling spray of dark materials. Bright south-facing slopes would exist primarily on young craters that have not been exposed to the darkening agent long enough to be stained. The image was obtained in visible light with the Cassini spacecraft narrow angle camera on Dec. 31, 2004, at a distance of about 123,370 kilometers (76,658 miles) from Iapetus and at a Sun-Iapetus-spacecraft, or phase, angle of 93 degrees. Resolution achieved in the original image was 732 meters (2,401 feet) per pixel. The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the mission for NASA's Science Mission Directorate, Washington, D.C. The Cassini orbiter and its two onboard cameras were designed, developed and assembled at JPL. The imaging team is based at the Space Science Institute, Boulder, Colo. For more information about the Cassini-Huygens mission visit http://saturn.jpl.nasa.gov [ http://saturn.jpl.nasa.gov ]. For images visit the Cassini imaging team home page http://ciclops.org [ http://ciclops.org ]., This oblique view of Saturn's moon Iapetus from high latitude shows how the dark, heavily cratered terrain of Cassini Regio transitions to a bright, icy terrain at high latitudes. In this mosaic of two high resolution images taken during Cassini?s New Year?s Eve 2004 flyby of Iapetus, the direction toward the north pole is approximately 15 degrees below the horizontal on the right. At the equator terrains are uniformly covered with a dark mantle of material that has a reflectivity of about 4 percent. At latitudes toward the pole of about 40 degrees, the dark deposits become patchy and diffuse as the surface transitions to a much brighter, icy terrain near the pole. The brightest icy materials exhibit visual reflectivity over 60 percent. Superimposed on the bright terrain is a subtle, ghostly pattern of crudely parallel, north-south trending wispy streaks. The streaks, which were discovered during this flyby of Iapetus, are typically a few kilometers wide and sometimes tens of kilometers long. Their appearance and orientation may be connected with the emplacement of dark materials that cover Cassini Regio. The dark materials might represent the gradual accumulation of dark debris falling from space, or alternatively, may represent fallout from plume-style eruptions that may have accompanied the formation of Iapetus's enigmatic equatorial ridge (see PIA06166 [ http://photojournal.jpl.nasa.gov/catalog/PIA06166 ] |
|
Fine Details of the Icy Surf
…
PIA00707
Jupiter
Solid-State Imaging
| Title |
Fine Details of the Icy Surface of Ganymede |
| Original Caption Released with Image |
Dramatic view of fine details in ice hills and valleys in an unnamed region on Jupiter's moon Ganymede. North is to the top of the picture and the sun illuminates the surface from the left. The finest details that can be discerned in this picture are only 11 meters across (similar to the size of an average house) some 2000 times better than previous images of this region. The bright areas in the left hand version are the sides of hills facing the sun, the dark areas are shadows. In the right hand version the processing has been changed to bring out details in the shadowed regions that are illuminated by the bright hillsides. The brightness of some of the hillsides is so high that the picture elements "spill over" down the columns of the picture. The image was taken on June 28, 1996 from a distance of about 1000 kilometers. The Jet Propulsion Laboratory, Pasadena, CA manages the mission for NASA's Office of Space Science, Washington, DC. This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo mission home page at URL http://galileo.jpl.nasa.gov. Background information and educational context for the images can be found at URL http://www.jpl.nasa.gov/galileo/sepo |
|
Ganymede Global
PIA00706
Jupiter
Solid-State Imaging
| Title |
Ganymede Global |
| Original Caption Released with Image |
View of Ganymede from the Galileo spacecraft during its first encounter with the Satellite. North is to the top of the picture and the sun illuminates the surface from the right. The finest details that can be discerned in this picture are about 6.7 kilometers across. The Universal Time is 8:45:09 UT on June 26, 1996. The Jet Propulsion Laboratory, Pasadena, CA manages the mission for NASA's Office of Space Science, Washington, DC. This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo mission home page at URL http://galileo.jpl.nasa.gov. Background information and educational context for the images can be found at URL http://www.jpl.nasa.gov/galileo/sepo |
|
Detail of Ganymede's Uruk Su
…
PIA00705
Jupiter
Solid-State Imaging
| Title |
Detail of Ganymede's Uruk Sulcus Region as Viewed by Galileo and Voyager |
| Original Caption Released with Image |
View of the region of Ganymede's Uruk Sulcus placed on a lower resolution Voyager view taken 17 years earlier. North is to the top of the picture and the sun illuminates the surface from almost overhead in the Galileo view. The finest details that can be discerned in the Galileo picture are about 80 meters across. The four boxes outlined in white show the extent of Galileo's initial look at this area. The Jet Propulsion Laboratory, Pasadena, CA manages the mission for NASA's Office of Space Science, Washington, DC. This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo mission home page at URL http://galileo.jpl.nasa.gov. Background information and educational context for the images can be found at URL http://www.jpl.nasa.gov/galileo/sepo |
|
Ganymede Color Global
PIA00716
Jupiter
Solid-State Imaging
| Title |
Ganymede Color Global |
| Original Caption Released with Image |
Natural color view of Ganymede from the Galileo spacecraft during its first encounter with the satellite. North is to the top of the picture and the sun illuminates the surface from the right. The dark areas are the older, more heavily cratered regions and the light areas are younger, tectonically deformed regions. The brownish-gray color is due to mixtures of rocky materials and ice. Bright spots are geologically recent impact craters and their ejecta. The finest details that can be discerned in this picture are about 13.4 kilometers across. The images which combine for this color image were taken beginning at Universal Time 8:46:04 UT on June 26, 1996. The Jet Propulsion Laboratory, Pasadena, CA manages the mission for NASA's Office of Space Science, Washington, DC. This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo mission home page at URL http://galileo.jpl.nasa.gov. Background information and educational context for the images can be found at URL http://www.jpl.nasa.gov/galileo/sepo |
|
Galileo Resolutions: Ganymed
…
PIA00722
Jupiter
Solid-State Imaging
| Title |
Galileo Resolutions: Ganymede and the San Francisco Bay Area |
| Original Caption Released with Image |
These frames demonstrate the dramatic improvement in the resolution of pictures that NASA's Galileo spacecraft is returning compared to previous images of the Jupiter system. The spacecraft's many orbits allow numerous close flyby's of Jupiter and its moons. The top left frame shows the best resolution (1.3 kilometers per picture element or pixel) data of the Uruk Sulcus region on Jupiter's moon Ganymede which was available after the 1979 flyby of the Voyager 2 spacecraft. The top right frame shows the same area as captured by Galileo during its closer flyby of Ganymede on June 27, 1996 at a range of 7,448 kilometers (4.628 miles). For comparison, the bottom frames show images of the San Francisco Bay area trimmed to the size of the Ganymede images and adjusted to similar resolutions. The Galileo image of Uruk Sulcus has a resolution of about 74 meters per pixel. The area shown is about 35 by 55 kilometers (25 by 34 miles). North is to the top, and the sun illuminates the surface from the lower left. The image taken by the Solid State Imaging (CCD) system reveals details of the structure and shape of the ridges which permit scientists to determine their origin and their relation to other terrains. These new views are helping to unravel the complex history of this planet-sized moon. The left SF Bay area image is from an image obtained by an Advanced Very High Resolution Radiometer aboard an NOAA satellite. The right SF Bay area image is from a LandSat Thematic Mapper. Golden Gate Park is clearly visible as a narrow dark rectangle towards the middle of this image. Both images were trimmed and adjusted to resolutions similar to the Ganymede images. The Jet Propulsion Laboratory, Pasadena, CA manages the mission for NASA's Office of Space Science, Washington, DC. This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo mission home page at URL http://galileo.jpl.nasa.gov. Background information and educational context for the images can be found at URL http://www.jpl.nasa.gov/galileo/sepo |
|
Pre-Dawn Temperatures on Gan
…
PIA01145
Jupiter
Photopolarimeter-Radiometer
| Title |
Pre-Dawn Temperatures on Ganymede |
| Original Caption Released with Image |
This infrared image of Jupiter's moon Ganymede, showing heat radiation from its surface at a wavelength of 27 microns (millionths of a meter), provides the best view yet of pre-dawn temperatures on Ganymede. Temperatures, derived from the brightness of the infrared radiation, can be determined from the colors by reference to the scale at the bottom of the image. The image, taken by NASA's Galileo spacecraft, shows half of Ganymede's disk as seen by the approaching spacecraft. Longitudes covered range from 340 on the right of the image, through longitude zero (the direction facing Jupiter) to longitude 60 near Ganymede's limb on the left. The morning terminator, near longitude 15, curves through the middle of the image, separating areas experiencing the last hours of the long (3.5 Earth day) Ganymede night, on the left, from areas that are warming up in the morning sunshine, on the right. Ganymede's north pole is in the upper right corner of the image, and the south pole is in the lower right. Ganymede rotates from left to right. Nighttime temperatures, shown in blue and purple colors, are in the range 85 - 100 Kelvin (-306 to -279 F). The surface cools steadily during the night, so the warmest nighttime temperatures are on the left side of the disk, and temperatures drop towards the dawn terminator on the right, before warming rapidly once the sun rises (the red, yellow and white areas on the far right). Study of the rate of nighttime cooling and the rate of post-sunrise warming, will provide information about Ganymede's surface properties. The image was taken with Galileo's PPR (Photopolarimeter-Radiometer) instrument on the spacecraft's seventh orbit around Jupiter, from a range of about 190,000 kilometers (118,060 miles). Surface temperatures derived from the strength of infrared radiation, as was done here, are called "brightness temperatures", and may be slightly in error. The PPR instrument builds up an image by slowly scanning across the target over a period of up to one hour. The motion of Galileo relative to Ganymede during this time causes distortions in the satellite shape on the image, which therefore appears slightly non-circular. The small overlapping circles that make up the image show the size of the area, about 450 kilometers (280 miles) across, covered by each individual PPR measurement. Blue spots in the dark sky in the left-hand portion of the image are due to noise. JPL manages the Galileo mission for NASA's Office of Space Science, Washington, D.C. |
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Nighttime Temperatures on Ga
…
PIA01146
Jupiter
Photopolarimeter-Radiometer
| Title |
Nighttime Temperatures on Ganymede |
| Original Caption Released with Image |
This infrared image of Jupiter's moon Ganymede, showing heat radiation from its surface at a wavelength of about 60 microns (millionths of a meter), provides the best view yet of nighttime temperatures on this hemisphere of Ganymede. Temperatures, derived from the brightness of the infrared radiation, can be determined from the colors by reference to the scale at the bottom of the image. The image, taken by NASA's Galileo spacecraft, shows most of Ganymede's nighttime hemisphere, centered on longitude 180 degrees, with north at the top. Irregular, diagonal dark stripes result from missing data, and are not real. Part of Ganymede's illuminated crescent, warmed by the late afternoon sun and appearing pink in this representation (indicating temperatures near 110 Kelvin (-260 F), is visible in the lower left, but most of the part of Ganymede that is seen here is in darkness, glowing only because it retains some heat from the previous day. Jupiter appears in the background behind Ganymede in the upper right part of the image. Although it is nighttime on this part of Jupiter, the planet remains much warmer at night than Ganymede does, with temperatures near 140 Kelvin (- 207 F), because Jupiter's atmosphere is too dense to cool down significantly during the night, and is also warmed by heat that flows up from Jupiter's interior. The coldest parts of Ganymede that are visible (appearing dark blue) are near the north and south poles, and have temperatures below 80 Kelvin (-315 F), while parts of the equator remain at temperatures up to 100 K (-279 F) through the night, and appear in bright blue and purple colors. This same side of Ganymede was seen in full sunlight on Galileo's first orbit around Jupiter, and similar measurements showed that noontime temperatures at the equator reached 150 K (-190 F), which is 90 degrees (Fahrenheit) warmer than the night-time temperatures seen here. The image was taken with Galileo's PPR (Photopolarimeter-Radiometer) instrument on the spacecraft's seventh orbit around Jupiter, from a range of about 65,000 kilometers (40,389 miles). Surface temperatures derived from the strength of infrared radiation, as was done here, are called "brightness temperatures", and may be slightly in error. The PPR instrument builds up an image by slowly scanning across the target over a period of up to one hour. The motion of Galileo relative to Ganymede during this time causes distortions in the satellite shape on the image, which therefore appears slightly non-circular. The small overlapping circles that make up the image show the size of the area, about 160 kilometers (99 miles) across, covered by each individual PPR measurement. Blue spots in the dark sky in the lower right are due to noise. JPL manages the Galileo mission for NASA's Office of Space Science, Washington, D.C. |
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Ice-frosted crater tops on G
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PIA00496
Jupiter
Solid-State Imaging
| Title |
Ice-frosted crater tops on Ganymede |
| Original Caption Released with Image |
Scientists believe that water-ice frosts are the likely cause for the brightening seen around the circular rims of these craters located at a high northern latitude (57 degrees) on Jupiter's moon Ganymede in this image taken by NASA's Galileo spacecraft on September 6, 1996. The image, just recently radioed to Earth from the spacecraft, shows the same kind of bright, high-latitude surface areas as those first seen by the Voyager spacecraft in 1979, but at higher resolution (this image spans about 18 kilometers or 11 miles on a side). Even though the Sun is shining from the south, the north-facing walls of the ridges and craters are brighter than the walls facing the Sun. This is interpreted to mean that the very bright north-facing slopes are covered with surface water-ice frosts, and that these frosts preferentially accumulate in such high-latitude locations. Galileo scientists say that at the high resolution seen in Galileo images, the high-latitude brightness seen by Voyager is partly attributable to frosts forming on cooler, north-facing slopes. The right-hand side of the image is dominated by a north-south line of impact craters, the smallest ones at the top are about 2 kilometers (1.2 miles) in diameter and the large one at the bottom is about 5 kilometers (about 3 miles) in diameter. Ganymede is the largest moon in the solar system, larger than the planet Mercury and nearly the size of Mars. The Jet Propulsion Laboratory, Pasadena, CA, manages the mission for NASA's Office of Space Science, Washington, DC. This image and other images and data received from Galileo are posted on the Galileo mission home page on the World Wide Web at http://galileo.jpl.nasa.gov. Background information and educational context for the images can be found at http://www.jpl.nasa.gov/galileo/sepo |
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Highly Fractured Dark and Br
…
PIA01616
Jupiter
Solid-State Imaging
| Title |
Highly Fractured Dark and Bright Terrain |
| Original Caption Released with Image |
View of a boundary between bright and dark terrain at the southern border of Galileo Regio on Jupiter's moon, Ganymede. A narrow, 15 kilometer wide, band of fractured bright terrain runs from the upper left to lower right of this image. The dark terrain on either side of this band of bright terrain has been highly fractured in multiple directions by tectonic activity. The large bright circular feature in the upper right is probably an impact crater that has been topographically relaxed, perhaps indicating that the subsurface was warm in this region at some point in its history before the formation of the bright terrain. Such images help determine how the ancient dark terrain on Ganymede was converted into younger bright terrain. North is to the top of the picture and the sun illuminates the surface from nearly overhead. The image, centered at 7 degrees latitude and 157 degrees longitude, covers an area approximately 81 by 58 kilometers. The resolution is 160 meters per picture element. The image was taken on May 7, 1997 at 15 hours, 21 minutes, 16 seconds Universal Time at a range of 16218 kilometers by the Solid State Imaging (SSI) system on NASA's Galileo spacecraft. The Jet Propulsion Laboratory, Pasadena, CA manages the Galileo mission for NASA's Office of Space Science, Washington, DC. This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo mission home page at URL http://galileo.jpl.nasa.gov [ http://www.jpl.nasa. gov/galileo ]. Background information and educational context for the images can be found at URL http://www.jpl.nasa.gov/galileo/sepo [ http://photojournal.jpl.nasa.gov/ /www.jpl.nasa.gov/galileo/sepo ] |
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Calderas" on Ganymede?
PIA01614
Jupiter
Solid-State Imaging
| Title |
Calderas" on Ganymede? |
| Original Caption Released with Image |
NASA's Galileo imaging camera targeted an area in Sippar Sulcus on Jupiter's moon, Ganymede. Images obtained in 1979 by NASA's Voyager spacecraft showed that the area contained curvilinear and arcuate scarps or cliffs. These features appeared to be depressions which were candidate sources for some of the water ice volcanism thought to form the bright grooved terrain on Ganymede. The high resolution Galileo images seen here reveal that one of these structures contains a lobate, flow-like feature that is the best candidate yet seen for an icy volcanic lava flow on Ganymede. The prominent depression with scalloped walls and internal terraces is about 55 kilometers (km) in length and 17 to 20 km wide. On the floor of the inner depression is a lobate flow-like deposit 7 to 10 km wide with ridges that are curved outward (and apparently downslope) toward a cross-cutting lane of grooved terrain. The morphology of this structure suggests the possibility of volcanic eruptions creating a channel and flow, and cutting down into the surface. North is to the bottom of the picture and the sun illuminates the surface from the left. The mosaic, centered at 31 degrees south latitude and 189 degrees longitude, covers an area approximately 91 by 62 kilometers. The resolution is 172 meters per picture element. The images were taken on May 7, 1997 at 15 hours, 18 minutes, 35 seconds Universal Time at a range of 17,489 kilometers by the Solid State Imaging(SSI) system on NASA's Galileo spacecraft. The Jet Propulsion Laboratory, Pasadena, CA manages the Galileo mission for NASA's Office of Space Science, Washington, DC. This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo mission home page at URL http://galileo.jpl.nasa.gov [ http://galileo.jpl.nasa.gov ] . Background information and educational context for the images can be found at URL http://www.jpl.nasa.gov/galileo/sepo [ http://www.jpl.nasa.gov/galileo/sepo ] |
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Ganymede's Nippur Sulcus
PIA00497
Jupiter
Solid-State Imaging
| Title |
Ganymede's Nippur Sulcus |
| Original Caption Released with Image |
New terrain overlays older terrain, which overlays still older surface, in this view of part of the surface of Jupiter's moon Ganymede, taken by the camera onboard NASA's Galileo spacecraft. Galileo obtained the images that make up this mosaic when it flew past Jupiter's moon Ganymede for the second time on September 6, 1996. An area about 54 kilometers (33 miles) wide and 90 kilometers (55 miles) high is shown. Northern Marius Regio (the dark terrain at bottom), Philus Sulcus (bright terrain at center), and Nippur Sulcus (bright terrain at top) are seen illuminated by the Sun from the southeast (north is at the top). The key characteristics and relationships of the major terrain types on tectonically active Ganymede are seen at a resolution 16 times better than images taken by the Voyager spacecraft in 1979. At the bottom, the ancient dark terrain is seen to be very deformed by tectonic fractures and faults. An impact crater about 18 kilometers (about 11 miles) in diameter has been highly modified by faulting. More recent cross-cutting fractures and faults at center illustrate to scientists the sequence of events that have created the younger bright terrain. The lines in the middle left of the image are faults that are cross-cut by younger faults in the upper part of the image. The smooth band in the upper middle of the image may represent water-ice volcanic deposits flooding a fault valley. Clusters of small craters, representing ejecta transported from distant craters and re-impacting here, are seen in the middle of the photo. The images that make up this mosaic were taken at a range of about 11,620 kilometers (about 7,200 miles). The Jet Propulsion Laboratory, Pasadena, CA, manages the mission for NASA's Office of Space Science, Washington, DC. This image and other images and data received from Galileo are posted on the Galileo mission home page on the World Wide Web at http://galileo.jpl.nasa.gov. Background information and educational context for the images can be found at http://www.jpl.nasa.gov/galileo/sepo |
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Galileo Regio Mosaic - Galil
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PIA00492
Jupiter
Solid-State Imaging
| Title |
Galileo Regio Mosaic - Galileo over Voyager Data |
| Original Caption Released with Image |
A mosaic of four Galileo images of the Galileo Regio region on Ganymede (Latitude 18 N, Longitude: 149 W) is shown overlayed on the data obtained by the Voyager 2 spacecraft in 1979. North is to the top of the picture, and the sun illuminates the surface from the lower left, about 58 degrees above the horizon. The smallest features that can be discerned are about 80 meters (262 feet) in size in the Galileo images. These Galileo images show fine details of the dark terrain that makes up about half of the surface of the planet-sized moon. Ancient impact craters of various sizes and states of degradation testify to the great age of the terrain, dating back several billion years. The images reveal distinctive variations in albedo from the brighter rims, knobs, and furrow walls to a possible accumulation of dark material on the lower slopes, and crater floors. High photometric activity (large light contrast at high spatial frequencies) of this ice-rich surface was such that the Galileo camera's hardware data compressor was pushed into truncating lines. The north-south running gap between the left and right halves of the mosaic is a result of line truncation from the normal 800 samples per line to about 540. The images were taken on 27 June, 1996 Universal Time at a range of 7,580 kilometers (4,738 miles) through the clear filter of the Galileo spacecraft's imaging system. Launched in October 1989, Galileo entered orbit around Jupiter on December 7, 1995. The spacecraft's mission is to conduct detailed studies of the giant planet, its largest moons and the Jovian magnetic environment. The Jet Propulsion Laboratory, Pasadena, CA manages the mission for NASA's Office of Space Science, Washington, DC. This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo mission home page at URL http://galileo.jpl.nasa.gov. Background information and educational context for the images can be found at URL http://www.jpl.nasa.gov/galileo/sepo |
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Uruk Sulcus Mosaic - Galileo
…
PIA00493
Jupiter
Solid-State Imaging
| Title |
Uruk Sulcus Mosaic - Galileo over Voyager Data |
| Original Caption Released with Image |
A mosaic of four Galileo images of the Uruk Sulcus region on Ganymede (Latitude 11 N, Longitude: 170 W) is shown overlayed on the data obtained by the Voyager 2 spacecraft in 1979. North is to the top of the picture, and the sun illuminates the surface from the lower left, nearly overhead. The area shown is about 120 by 110 kilometers (75 by 68 miles) in extent and the smallest features that can be discerned are 74 meters (243 feet) in size in the Galileo images and 1.3 kilometers (0.8 miles) in the Voyager data. The higher resolution Galileo images unveil the details of parallel ridges and troughs that are principal features in the brighter regions of Ganymede. High photometric activity (large light contrast at high spatial frequencies) of this ice-rich surface was such that the Galileo camera's hardware data compressor was pushed into truncating lines. The north-south running gap between the left and right halves of the mosaic is a result of line truncation from the normal 800 samples per line to about 540. The images were taken on 27 June, 1996 Universal Time at a range of 7,448 kilometers (4,628 miles) through the clear filter of the Galileo spacecraft's imaging system. Launched in October 1989, Galileo entered orbit around Jupiter on December 7, 1995. The spacecraft's mission is to conduct detailed studies of the giant planet, its largest moons and the Jovian magnetic environment. The Jet Propulsion Laboratory, Pasadena, CA manages the mission for NASA's Office of Space Science, Washington, DC. This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo mission home page at URL http://galileo.jpl.nasa.gov. Background information and educational context for the images can be found at URL http://www.jpl.nasa.gov/galileo/sepo |
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Fresh Impact Craters on Gany
…
PIA01609
Jupiter
Solid-State Imaging
| Title |
Fresh Impact Craters on Ganymede |
| Original Caption Released with Image |
Oblique view of two fresh impact craters in bright grooved terrain near the north pole of Jupiter's moon, Ganymede. The craters postdate the grooved terrain since each is surrounded by swarms of smaller craters formed by material which was ejected out of the crater as it formed, and which subsequently reimpacted onto the surrounding surface. The crater to the north, Gula, which is 38 kilometers (km) in diameter, has a distinctive central peak, while the crater to the south, Achelous, (32 km in diameter) has an outer lobate ejecta deposit extending about a crater radius from the rim. Such images show the range of structural details of impact craters, and help in understanding the processes that form them. North is to the top of the picture and the sun illuminates the surface from the right. The image, centered at 62 degrees latitude and 12 degrees longitude, covers an area approximately 142 by 132 kilometers. The resolution is 175 meters per picture element. The images were taken on April 5, 1997 at 6 hours, 33 minutes, 37 seconds Universal Time at a range of 17,531 kilometers by the Solid State Imaging (SSI) system on NASA's Galileo spacecraft. The Jet Propulsion Laboratory, Pasadena, CA manages the Galileo mission for NASA's Office of Space Science, Washington, DC. This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo mission home page at URL http:// galileo.jpl.nasa.gov [ http://galileo.jpl.nasa.gov ]. Background information and educational context for the images can be found at URL http://www.jpl.nasa.gov/galileo/sepo [ http://www.jpl.nasa.gov/galileo/sepo ] |
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Dome crater Neith on Jupiter
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PIA01658
Jupiter
Solid-State Imaging
| Title |
Dome crater Neith on Jupiter's satellite Ganymede |
| Original Caption Released with Image |
This image shows crater Neith, an unusual impact structure about 160 km (100 miles) in diameter, situated on Jupiter's largest satellite, Ganymede. Impact features like Neith have been called "penepalimpsests" by some investigators or "dome craters" by others and are considered to be transitional between craters and palimpsests. Palimpsests are bright, nearly circular patches that are believed to be remnant impact features. They occur also on Callisto, Ganymede's neighbor farther distant from Jupiter. Four images of Neith were obtained under low sun elevation in April 1997 during Galileo's 7th orbit around Jupiter with the Solid State Imaging (SSI) system from a distance of about 15,500 km (9,600 miles) to produce this mosaic. The pixel resolution is about 150 m/pixel - the smallest features that are still discernible are about 300 m across. The sun illuminates the scene from the right. North is approximately pointing towards the top of the mosaic. Neith is situated at about 29 degrees northern latitude and 9 degrees western longitude on Ganymede. The most striking feature in Neith is a large, circular dome about 45 km in diameter. The dome is surrounded by a wreath of rugged terrain. The wreath does not represent the original crater rim but the rim of a large central pit instead. The rim itself is barely visible and is located along the outer boundary of a relatively smooth, circular area, assumed to be the crater floor, which in turn surrounds the wreath of rugged terrain. In some parts along the rim, inward-facing scarps may be seen. The rim is not circular but appears to be petal-shaped. Outside the rim, a continuous ejecta blanket may be discerned. The morphology of impact features such as Neith results either from the response of a relatively weak target material to a high-energy impact or from long-term viscous relaxation of the surface subsequent to impact. Absolute ages derived from crater frequency measurements are model-dependent. In one crater chronology model, based on impacts dominated by asteroids, Neith may be old and very likely was formed during a period of more intense bombardment than today, about 3.9 billion years ago. In a different model, based on impacts preferentially by comets with a more or less constant impact rate, Neith may be only about 1 billion years old. The Jet Propulsion Laboratory, Pasadena, CA manages the Galileo mission for NASA's Office of Space Science, Washington, DC. This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo mission home page at URL http://galileo.jpl.nasa.gov [ http://galileo.jpl.nasa.gov ]. Background information and educational context for the images can be found at URL http://www.jpl.nasa.gov/galileo/sepo [ http://www.jpl.nasa.gov/galileo/sepo ]. |
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A Tumultuous Past for Ganyme
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PIA01612
Jupiter
Solid-State Imaging
| Title |
A Tumultuous Past for Ganymede's Dark Terrain |
| Original Caption Released with Image |
Dark terrain of Nicholson Regio on Jupiter's moon, Ganymede. On the left is a crater that has been torn apart by tectonic forces. A lane of ridges and grooves (probably extensional fault blocks) cuts through the crater and distorts its originally circular shape. Though such deformation is more typical of Ganymede's bright grooved terrain, this image demonstrates that extreme tectonic disruption has occurred in the satellite's dark terrain also. The pair of oblong craters on the right was formed by the impact of a gravitationally bound pair of asteroids or a split comet. The oblong shapes of the craters suggest that the impactors struck the surface at a shallow angle. Toward the top left, an old crater has been partially buried by dark ejecta tossed from another impact about 50 kilometers to the north of this image. North is to the top of the picture and the sun illuminates the surface from the right. The image, centered at 14 degrees south latitude and 352 degrees longitude, covers an area approximately 111 by 93 kilometers. The resolution is 180 meters per picture element. The image was taken on April 5, 1997 at 6 hours, 31 minutes, 44 seconds Universal Time at a range of 17,840 kilometers by the Solid State Imaging (SSI) system on NASA's Galileo spacecraft. The Jet Propulsion Laboratory, Pasadena, CA manages the Galileo mission for NASA's Office of Space Science, Washington, DC. This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo mission home page at URL http://galileo.jpl.nasa.gov [ http://galileo.jpl.nasa.gov ] . Background information and educational context for the images can be found at URL http://www.jpl.nasa.gov/galileo/sepo [ http://www.jpl.nasa.gov/galileo/sepo ] |
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Marius Regio, Ganymede
PIA01617
Jupiter
Solid-State Imaging
| Title |
Marius Regio, Ganymede |
| Original Caption Released with Image |
This image shows a highly fractured lane of grooved terrain, Lagash Sulcus, which runs through an area of heavily cratered dark terrain within Marius Regio on Jupiter's moon Ganymede. The boundary between these two units is marked by a deep trough. Outside the groove lane, little fracturing is evident, suggesting that deformation is largely concentrated within the bright grooved area. The bright, heart-shaped feature just below the image center may be a patch of bright terrain, or the feature may be related to ancient impact event. North is to the top of the picture and the sun illuminates the surface from the upper right. The image, centered at 17 degrees south latitude and 156 degrees longitude, covers an area approximately 230 by 230 kilometers. The resolution is 288 meters per picture element. The images were taken on June 6, 1997 at 14 hours, 56 minutes, 11 seconds Universal Time at a range of 28655 kilometers by the Solid State Imaging (SSI) system on NASA's Galileo spacecraft. The Jet Propulsion Laboratory, Pasadena, CA manages the Galileo mission for NASA's Office of Space Science, Washington, DC. This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo mission home page at URL http:// galileo.jpl.nasa.gov [ http://galileo.jpl.nasa.gov ]. Background information and educational context for the images can be found at URL http://www.jpl.nasa.gov/galileo/sepo [ http://www.jpl.nasa.gov/galileo/sepo ] |
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Regional View of Ganymede
PIA01618
Jupiter
Solid-State Imaging
| Title |
Regional View of Ganymede |
| Original Caption Released with Image |
View of the Marius Regio and Nippur Sulcus area of Jupiter's moon, Ganymede showing the dark and bright grooved terrain which is typical of this satellite. This regional scale view was imaged near the terminator (the line between day and night) and provides geologic context for small areas that were imaged at much higher resolution earlier in the tour of NASA's Galileo spacecraft through the Jovian system. The older, more heavily cratered dark terrain of Marius Regio is rutted with furrows, shallow troughs perhaps formed as a result of ancient giant impacts. Bright grooved terrain is younger and is formed through tectonism probably combined with icy volcanism. The lane of grooved terrain in the lower left, Byblus Sulcus [ http://photojournal.jpl.nasa.gov/catalog/PIA01088 ], was imaged during the spacecraft's second orbit, as were Philus Sulcus and Nippur Sulcus [ http://photojournal.jpl.nasa.gov/catalog/PIA00497 ], seen here in the upper left. Placing the small higher resolution targets of Galileo's second orbit into the context of more distant, lower resolution views of the areas surrounding and connecting them, and imaging them along Ganymede's terminator, allows for an integrated understanding of Ganymede' s geology. North is to the top left of the picture and the sun illuminates the surface from the lower right. The image, centered at 43 degrees latitude and 194 degrees longitude, covers an area approximately 664 by 518 kilometers. The resolution is 940 meters per picture element. The image was taken on May 7, 1997 at 12 hours, 50 minutes, 11 seconds Universal Time at a range of 92,402 kilometers by the Solid State Imaging (SSI) system on NASA's Galileo spacecraft. The Jet Propulsion Laboratory, Pasadena, CA manages the Galileo mission for NASA's Office of Space Science, Washington, DC. This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo mission home page at URL http://galileo.jpl.nasa.gov [ http://galileo.jpl.nasa.gov ] . Background information and educational context for the images can be found at URL http://www.jpl.nasa.gov/galileo/sepo [ http://www.jpl.nasa.gov/galileo/sepo ] |
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Pedestal craters Gula and Ac
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PIA01660
Jupiter
Solid-State Imaging
| Title |
Pedestal craters Gula and Achelous on Ganymede |
| Original Caption Released with Image |
This image shows a Galileo high-resolution mosaic of craters Gula (top), about 40 km (25 miles) in diameter, and Achelous (bottom), about 35 km (21.8 miles) in diameter, projected on a lower-resolution background of image data that were obtained in the late 70s by the NASA Voyager spacecraft. The two Galileo frames used for the mosaic of Gula and Achelous were taken under low sun elevation in April 1997 during Galileo's 7th orbit around Jupiter with the Solid State Imaging (SSI) camera system onboard this NASA spacecraft that has been orbiting Jupiter since December 1995. The images were taken from a distance of about 17,500 km from Ganymede. The pixel resolution is about 180 m/pixel - the smallest features that are still discernible are about 360 m across. The sun illuminates the scene from the right. North is pointing towards the top of the Galileo mosaic. Both craters are situated between 60 and 65 degrees northern latitude at about 12.5 degrees western longitude. A characteristic feature of both craters, almost identical in size, is the "pedestal" - an outward-facing, relatively gently sloped scarp that terminates the continuous ejecta blanket. Similar features may be seen in ejecta blankets of Martian craters, suggesting impacts into a volatile (ice)-rich target material. Furthermore, both craters appear crisp and feature terraces. Gula has a prominent central peak, Achelous instead may show the remnant of a collapsed central peak or a central pit that is not fully formed. On lower-resolution images taken under higher sun illumination angle, both craters are shown to have extended bright rays, especially Achelous, which demonstrates that these two craters are younger than the respective surrounding landscape. The Jet Propulsion Laboratory, Pasadena, CA manages the Galileo mission for NASA's Office of Space Science, Washington, DC. This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo mission home page at URL http://galileo.jpl.nasa.gov [ http://galileo.jpl.nasa.gov ]. Background information and educational context for the images can be found at URL http://www.jpl.nasa.gov/galileo/sepo [ http://www.jpl.nasa.gov/galileo/sepo ]. |
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Kittu Dark Ray Crater
PIA01611
Jupiter
Solid-State Imaging
| Title |
Kittu Dark Ray Crater |
| Original Caption Released with Image |
View of the dark ray crater Kittu on Jupiter's moon, Ganymede. Kittu is seen in approximately true color, as imaged with the Galileo camera's violet, one micrometer, and near infrared filters. The crater shows a bright white central peak and rim, and dark brownish material surrounding it. Diffuse dark rays, sprinkled thinly atop surrounding grooved terrain, emanate from the impact site. The dark material dusted over the surface is probably part of a dark impactor (asteroid or comet) which was strewn across the surface upon impact. The impactor hit grooved terrain, and a straight segment of the crater's rim was created when a portion of the rim collapsed along the trend of an older fault. North is to the bottom of the picture and the sun illuminates the surface from the left. The mosaic, centered at 0 degrees latitude and 335 degrees longitude, covers an area approximately 70 by 100 kilometers. The resolution in the color portion of this image is about 280 meters per picture element, while the resolution in the black and white portion is 145 meters per picture element. The images were taken beginning on April 5, 1997 from 6 hours, 39 minutes, 46 seconds Universal Time at a range of 14252 kilometers by the Solid State Imaging (SSI) system on NASA's Galileo spacecraft. The Jet Propulsion Laboratory, Pasadena, CA manages the Galileo mission for NASA's Office of Space Science, Washington, DC. This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo mission home page at URL http://www.jpl.nasa.gov/galileo/sepo [ http://galileo.jpl.nasa.gov/galileo/sepo ] |
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