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Callisto Hemispherical Globe
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PIA03876
Jupiter
Imaging Science Subsystem, S
…
| Title |
Callisto Hemispherical Globes |
| Original Caption Released with Image |
The images used for the base of this globe were chosen from the best image quality and moderate resolution coverage supplied by Galileo SSI and Voyager 1 and 2 (Batson, 1987, Becker and others, 1998, Becker and others, 1999, Becker and others, 2001). The digital map was produced using Integrated Software for Imagers and Spectrometers (ISIS) (Eliason, 1997, Gaddis and others, 1997, Torson and Becker, 1997). The individual images were radiometrically calibrated and photometrically normalized using a Lunar-Lambert function with empirically derived values (McEwen, 1991, Kirk and others, 2000). A linear correction based on the statistics of all overlapping areas was then applied to minimize image brightness variations. The image data were selected on the basis of overall image quality, reasonable original input resolution (from 20 km/pixel for gap fill to as much as 150 m/pixel), and availability of moderate emission/incidence angles for topography. Although consistency was achieved where possible, different filters were included for global image coverage as necessary: clear for Voyager 1 and 2, clear and green (559 nm) for Galileo SSI. Individual images were projected to a Sinusoidal Equal-Area projection at an image resolution of 1.0 kilometer/pixel, and a final global mosaic was constructed in this same projection. The final mosaic was enhanced using commercial software. The global mosaic was then reprojected so that the entire surface of Callisto is portrayed in a manner suitable for the production of a globe. A specialized program was used to create the "flower petal" appearance of the images, the area of each petal from 0 to 75 degrees latitude is in the Transverse Mercator projection, and the area from 75 to 90 degrees latitude is in the Lambert Azimuthal Equal-Area projection. The projections for adjacent petals overlap by 2 degrees of longitude, so that some features are shown twice. The northern hemisphere is shown on the left, and the southern hemisphere is shown on the right. Names shown on the globe are approved by the International Astronomical Union. The number, size, and placement of text were chosen for a 9-inch globe. A complete list of Callisto nomenclature can be found at the Gazetteer of Planetary Nomenclature (http://planetarynames.wr.usgs.gov). |
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Asgard Multi-Ring Structure
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PIA01634
Jupiter
Solid-State Imaging
| Title |
Asgard Multi-Ring Structure on Callisto |
| Original Caption Released with Image |
This mosaic shows the Asgard multi-ring structure on Callisto, Jupiter's second largest icy moon. The Asgard structure [ http://photojournal.jpl.nasa.gov/catalog/PIA00517 ], centered near 30 degrees north latitude, 142 degrees west longitude, is approximately 1700 km across (1,056 miles) and consists of a bright central zone surrounded by discontinuous rings. The rings are fractures that formed when Callisto's surface was struck by a large comet or asteroid. Previous analysis of Asgard identified three major zones: 1) interior bright plains in the center, 2) a zone of inward facing cliffs and, 3) a zone of discontinuous concentric troughs. The mosaic combines high resolution data of 88 meters per picture element (pixel) taken on the tenth orbit of the Galileo spacecraft around Jupiter in September 1997, with low resolution data of 1.1 kilometers (km) per pixel obtained on the third orbit in November 1996. The improved resolution of images obtained by the Solid State Imaging (SSI) system on board NASA's Galileo spacecraft allows for new insights into the Asgard multi-ring system. Galileo images show that the bright central plains includes a young dome crater, named Doh, located on its southwestern margin (at the top of the high resolution strip). Doh is about 50 km (30 miles) in diameter. Dome craters contain a central mound instead of a bowl shaped depression or the central mountain typically seen in craters. The inner rings of Asgard appear to be degraded ridges in the high resolution data, rather than inward-facing cliffs or scarps as previously interpreted from lower resolution images. In the outermost rings, dark non-ice material that slid down the walls of the troughs has made their floors darker than the surrounding cratered plains. North is to the top of the picture. The high resolution images were obtained with the clear filter of the Solid State Imaging (SSI) system when NASA's Galileo spacecraft was less than 9,500 kilometers from Callisto. There appears to be a diffuse darker stripe, beginning near the middle and continuing down the strip of higher resolution frames. This darkening is due to the processing used to place the higher resolution frames into the background context. The Jet Propulsion Laboratory, Pasadena, CA manages the Galileo mission or 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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Asgard impact structure on C
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PIA00517
Jupiter
Solid-State Imaging
| Title |
Asgard impact structure on Callisto |
| Original Caption Released with Image |
This four-frame mosaic shows the ancient impact structure Asgard on Jupiter's moon Callisto. This image is centered at 30 degrees north, 142 degrees west. The Asgard structure is approximately 1700 km across (1,056 mi) and consists of a bright central zone surrounded by discontinuous rings. The rings are tectonic features with scarps near the central zone and troughs at the outer margin. Several large impacts have smashed into Callisto after the formation of Asgard. The very young, bright-rayed crater Burr is located on the northern part of Asgard. This mosaic has been projected to show a uniform scale between the four mosaiced images. The image was processed by Deutsche Forschungsanstalt fuer Luftund Raumfahrt e.V., Berlin, Germany. This image was taken on November 4, 1996, at a distance of 111,891 kilometers (69,070 miles) by the solid state imaging television camera onboard the Galileo spacecraft during its third orbit around Jupiter. The Galileo mission is managed by the Jet Propulsion Laboratory for NASA's Office of Space Science, Washington, D.C. 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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Crater Tindr on Callisto - a
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PIA01657
Jupiter
Solid-State Imaging
| Title |
Crater Tindr on Callisto - an oblique impact? |
| Original Caption Released with Image |
This single-frame image shows crater Tindr on Jupiter's satellite Callisto, the moon with the oldest surface of the four so-called "Galilean" satellites (of which Callisto is also most distant from Jupiter). The diameter of this impact feature is about 70 km (43.5 miles). Tindris situated close to Callisto's equator at a longitude of about 5 degrees East. The image was obtained in September 1997 with the Solid State Imaging (SSI) system onboard NASA's Galileo spacecraft, which has been orbiting the Solar System's largest planet since December 1995. Shadows are long and accentuate morphology on the surface, because the image was taken under low sun illumination. The image was captured from a distance of about 40,000 km(25,000 miles) during Galileo's 10th orbit around Jupiter. The resolution is about 390 m/pixel, the smallest features that are still discernible are about 780 m across. The sun illuminates the scene from the left. North is pointing towards the top of the image. The image covers an area approximately 150 x 150 km. Tindr is slightly irregular in shape. This could be the consequence of an oblique impact. Along its eastern and southeastern part, the rim appears degraded, only isolated hills or hill chains are still visible. The floor shows numerous irregular pits, features that are found in some other Callistoan craters and also in Callisto's dark cratered plains. These features are believed to be caused by sublimation of subsurface volatiles. Subradial streaks outside the crater rim are due to impact debris creating secondary craters some distance away from Tindr. Continuous ejecta covers several older craters, especially in the northeastern part of the scene. The Tindr ejecta merge into surrounding cratered plains without a distinct morphologic or albedo boundary. Apparently the dark material blanketing Callisto's surface globally was emplaced after Tindr had formed. Absolute ages derived from measured crater densities are model-dependent. In one crater chronology model, based on impacts dominated by asteroids, Tindr may be an old feature, about 3.9 billion years old, pointing back in time into a period of more intense bombardment than today. In another model, based on impacts preferentially by comets with a more or less constant impact rate, Tindr can be much younger, 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 Chain of Impact Craters on
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PIA00514
Jupiter
Solid-State Imaging
| Title |
A Chain of Impact Craters on Callisto |
| Original Caption Released with Image |
A portion of a chain of impact craters on Jupiter's moon Callisto is seen in this image taken by the Galileo spacecraft on November 4, 1996. This crater chain on Callisto is believed to result from the impact of a split object, similar to the fragments of Comet Shoemaker-Levy 9 which smashed into Jupiter's atmosphere in July of 1994. This high-resolution view, taken by Galileo's solid state imaging television camera during its third orbit around Jupiter, is of Callisto's northern hemisphere at 35 degrees north, 46 degrees west, and covers an area of about eight miles (13 kilometers) across. The smallest visible crater is about 140 yards (130 meters) across. The image was taken at a range of 974 miles (1,567 kilometers). On a global scale, Callisto is heavily cratered, indicating the great age of its surface. At the scale of this image, it was anticipated that the surface would be heavily cratered as well, however, there is a surprising lack of small craters, suggesting that one or more processes have obliterated these and other small-scale features. For example, downslope movement of ice-rich debris could bury small craters. The bright slopes visible in this picture represent places where downslope movement has taken place, exposing fresh ice surfaces. The Galileo mission is managed by the Jet Propulsion Laboratory for NASA's Office of Space Science, Washington, D.C. 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/ [ http://galileo.jpl.nasa.gov/ ]. Background information and educational context for the images can be found at http://www2.jpl.nasa.gov/galileo/sepo/ [ http://www2.jpl.nasa.gov/galileo/sepo/ ]. |
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Callisto's Valhalla impact s
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PIA00516
Jupiter
Solid-State Imaging
| Title |
Callisto's Valhalla impact structure |
| Original Caption Released with Image |
A portion of the central zone of the large impact structure Valhalla on Jupiter's moon Callisto was imaged by the Galileo spacecraft on November 4, 1996. The area shown here is centered at 16 degrees north, 55 degrees west and is about seven miles (11 kilometers) across. This is the highest resolution picture ever taken of Callisto and shows features as small as 200 feet (60 meters) across. The formation of Valhalla occurred early in Callisto's history, however, the central zone shown here is probably younger than Valhalla's surrounding structure. This newly acquired picture shows some small craters, although they have been softened or modified by downslope movement of debris, revealing bright ice-rich surfaces. In contrast to other areas on Callisto, most of the very smallest craters appear to have been completely obliterated. This image was taken by the solid state imaging television camera onboard the Galileo spacecraft during its third orbit around Jupiter, at a distance of 757 miles (1,219 kilometers). The Galileo mission is managed by the Jet Propulsion Laboratory for NASA's Office of Space Science, Washington, D.C. 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/ [ http://galileo.jpl.nasa.gov/ ]. Background information and educational context for the images can be found at http://www2.jpl.nasa.gov/galileo/sepo/ [ http://www2.jpl.nasa.gov/galileo/sepo/ ]. |
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Europa, Ganymede, and Callis
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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 |
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Gaspra - True and Enhanced C
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PIA00125
Sol (our sun)
Solid-State Imaging
| Title |
Gaspra - True and Enhanced Color |
| Original Caption Released with Image |
These two color views of the asteroid Gaspra were produced by combining three images taken through violet, green, and infrared filters by the Galileo spacecraft on October 29, 1991, from a distance of about 16,000 kilometers (10,000 miles). The view on the left shows Gaspra in approximately true color, the surface is covered with rocks that are somewhat less grey than those on Earth's moon. In the version on the right, the colors were enhanced to bring out the muted color variations on the asteroid and to increase the ability to discriminate between surface features. The subtle variations in color may be due to slight differences in rock composition or to differences in the texture of the surface layer. These possibilities should be resolved once the rest of Galileo's Gaspra data are played back in 1992. Gaspra is about 19 by 12 by 11 kilometers (12 by 7.4 by 7 miles) and irregular in shape. The illuminated portion seen in these views is about 16 by 12 kilometers. These color images were produced for the Galileo project by the U.S. Geological survey, Flagstaff, Arizona. The Galileo project whose primary mission is the exploration of the Jupiter system in 1995-97, is managed for NASA's Office of Space Science and Applications by the Jet Propulsion Laboratory. |
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Highest Resolution Gaspra Mo
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PIA00119
Sol (our sun)
Solid-State Imaging
| Title |
Highest Resolution Gaspra Mosaic |
| Original Caption Released with Image |
This picture of asteroid 951 Gaspra is a mosaic of two images taken by the Galileo spacecraft from a range of 5,300 kilometers (3,300 miles), some 10 minutes before closest approach on October 29, 1991. The Sun is shining from the right, phase angle is 50 degrees. The resolution, about 54 meters/pixel, is the highest for the Gaspra encounter and is about three times better than that in the view released in November 1991. Additional images of Gaspra remain stored on Galileo's tape recorder, awaiting playback in November. Gaspra is an irregular body with dimensions about 19 x 12 x 11 kilometers (12 x 7.5 x 7 miles). The portion illuminated in this view is about 18 kilometers (11 miles) from lower left to upper right. The north pole is located at upper left, Gaspra rotates counterclockwise every 7 hours. The large concavity on the lower right limb is about 6 kilometers (3.7 miles) across, the prominent crater on the terminator, center left, about 1.5 kilometers (1 mile). A striking feature of Gaspra's surface is the abundance of small craters. More than 600 craters, 100-500 meters (330-1650 feet) in diameter are visible here. The number of such small craters compared to larger ones is much greater for Gaspra than for previously studied bodies of comparable size such as the satellites of Mars. Gaspra's very irregular shape suggests that the asteroid was derived from a larger body by nearly catastrophic collisions. Consistent with such a history is the prominence of groove-like linear features, believed to be related to fractures. These linear depressions, 100-300 meters wide and tens of meters deep, are in two crossing groups with slightly different morphology, one group wider and more pitted than the other. Grooves had previously been seen only on Mars's moon Phobos, but were predicted for asteroids as well. Gaspra also shows a variety of enigmatic curved depressions and ridges in the terminator region at left. The Galileo project, whose primary mission is the exploration of the Jupiter system in 1995-97, is managed for NASA's Office of Space Science and Applications by the Jet Propulsion Laboratory. |
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Asteroid Ida - 6 Views Showi
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PIA00137
Sol (our sun)
Solid-State Imaging
| Title |
Asteroid Ida - 6 Views Showing Rotation |
| Original Caption Released with Image |
This composite image shows the asteroid 243 Ida as seen from the Galileo spacecraft during its approach on August 28, 1993. The six views were shuttered through the camera's green filter and show Ida's rotation over a period of about 3 hours 18 minutes. The asteroid makes a complete rotation every 4 hours 38 minutes, therefore, this set of images spans about 3/4 of Ida's rotation period and shows most of Ida's surface. By combining the information in these views with that from the highest resolution images returned from the spacecraft in September 1993, the size and shape of this irregular body can now be determined accurately The asteroid appears to be about 58 kilometers (36 miles) long and about 23 kilometers wide, with a very irregular shape and volume of some 16,000 cubic kilometers. The images are arranged in chronological order from a time 3 hours 51 minutes before closest approach (upper left), through upper right, middle left, middle right lower left and lower right (33 minutes before closest approach). The six images show Ida at the same scale throughout. Ida's rotation axis is roughly vertical in these images, and the rotation causes the right-hand end of Ida to move toward the viewer as time progresses. The first image was taken from a range of about 171,000 km (106,000 miles) and provides an image resolution of about 1,700 meters per pixel (the highest resolution achieved for Ida is about 25 meters per pixel). The second, taken 70 minutes later, is from 119,000 kilometers, followed by 102,000 kilometers, 85,000 kilometers, 50,000 kilometers, and 25,000 kilometers. The features on Ida are less sharp in the earlier views because of the greater distances. Prominent in the middle three views is a deep depression across the short axis of the Asteroid. This feature tends to support the idea that Ida may have originally been formed from two or more separate large objects that collided softly and stuck together. Also visible in the lower left view is an apparent linear albedo or reflectance boundary. Color images yet to be returned from the Galileo spacecraft may help resolve the question of whether or not the two ends of Ida are made of different materials. |
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Moon - False Color Mosaic
PIA00132
Earth
Solid-State Imaging
| Title |
Moon - False Color Mosaic |
| Original Caption Released with Image |
This false-color photograph is a composite of 15 images of the Moon taken through three color filters by Galileo's solid-state imaging system during the spacecraft's passage through the Earth-Moon system on December 8, 1992. When this view was obtained, the spacecraft was 425,000 kilometers (262,000 miles) from the Moon and 69,000 kilometers (43,000 miles) from Earth. The false-color processing used to create this lunar image is helpful for interpreting the surface soil composition. Areas appearing red generally correspond to the lunar highlands, while blue to orange shades indicate the ancient volcanic lava flow of a mare, or lunar sea. Bluer mare areas contain more titanium than do the orange regions. Mare Tranquillitatis, seen as a deep blue patch on the right, is richer in titanium than Mare Serenitatis, a slightly smaller circular area immediately adjacent to the upper left of Mare Tranquillitatis. Blue and orange areas covering much of the left side of the Moon in this view represent many separate lava flows in Oceanus Procellarum. The small purple areas found near the center are pyroclastic deposits formed by explosive volcanic eruptions. The fresh crater Tycho, with a diameter of 85 kilometers (53 miles), is prominent at the bottom of the photograph, where part of the Moon's disk is missing. |
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Asteroid Ida - Five Frame Mo
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PIA00135
Sol (our sun)
Solid-State Imaging
| Title |
Asteroid Ida - Five Frame Mosaic |
| Original Caption Released with Image |
This view of the asteroid 243 Ida is a mosaic of five image frames acquired by the Galileo spacecraft's solid-state imaging system at ranges of 3,057 to 3,821 kilometers (1,900 to 2,375 miles) on August 28, 1993, about 3-1/2 minutes before the spacecraft made its closest approach to the asteroid. Galileo flew about 2,400 kilometers (1,500 miles) from Ida at a relative velocity of 12.4 km/sec (28,000 mph). Asteroid and spacecraft were 441 million kilometers (274 million miles) from the Sun. Ida is the second asteroid ever encountered by a spacecraft. It appears to be about 52 kilometers (32 miles) in length, more than twice as large as Gaspra, the first asteroid observed by Galileo in October 1991. Ida is an irregularly shaped asteroid placed by scientists in the S class (believed to be like stony or stony iron meteorites). It is a member of the Koronis family, presumed fragments left from the breakup of a precursor asteroid in a catastrophic collision. This view shows numerous craters, including many degraded craters larger than any seen on Gaspra. The extensive cratering seems to dispel theories about Ida's surface being geologically youthful. This view also seems to rule out the idea that Ida is a double body. The south pole is believed to be in the darkside near the middle of the asteroid. The camera's clear filter was used to produce this extremely sharp picture. Spatial resolution is 31 to 38 meters (roughly 100 feet) per pixel. A 30-frame mosaic was taken to assure capturing Ida, its position was somewhat uncertain before the Galileo encounter. Galileo shuttered and recorded a total of 150 images in order to capture Ida 21 different times during a five hour period (about one rotation of the asteroid). Color filters were used at many of these times to allow reconstruction of color images. Playback to Earth of the remaining images is planned for April through June 1994. The Galileo project, whose primary mission is the exploration of the Jupiter system in 1995-97, is managed for NASA's Office of Space Science by the Jet Propulsion Laboratory. |
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Asteroid Ida - Limb at Close
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PIA00138
Sol (our sun)
Solid-State Imaging
| Title |
Asteroid Ida - Limb at Closest Approach |
| Original Caption Released with Image |
The Galileo imaging system captured this picture of the limb of the asteroid 243 Ida about 46 seconds after its closest approach on August 28, 1993, from a range of only 2480 kilometers. It is the highest-resolution image of an asteroid's surface ever captured and shows detail at a scale of about 25 meters per pixel. This image is one frame of a mosaic of 15 frames shuttered near Galileo's closest approach to Ida. Since the exact location of Ida in space was not well-known prior to the Galileo flyby, this mosaic was estimated to have only about a 50 percent chance of capturing Ida. Fortunately, this single frame did successfully image a part of the sunlit side of Ida. The area seen in this frame shows some of the same territory seen in a slightly lower resolution full disk mosaic of Ida returned from the spacecraft in September, 1993, but from a different perspective. Prominent in this view is a 2 kilometer deep "valley" seen in profile on the limb. This limb profile and the stereoscopic effect between this image and the full disk mosaic will permit detailed refinement of Ida's shape in this region. This high resolution view shows many small craters and some grooves on the surface of Ida, which give clues to understanding the history of this heavily impacted object. The Galileo project, whose primary mission is the exploration of the Jupiter system in 1995-97, is managed for NASA's Office of Space Science by the Jet Propulsion Laboratory. |
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Moon - 18 Image Mosaic
PIA00128
Earth
Solid-State Imaging
| Title |
Moon - 18 Image Mosaic |
| Original Caption Released with Image |
This mosaic picture of the Moon was compiled from 18 images taken with a green filter by Galileo's imaging system during the spacecraft's flyby on December 7, 1992, some 11 hours before its Earth flyby at 1509 UTC (7:09 a.m. Pacific Standard Time) December 8. The north polar region is near the top part of the mosaic, which also shows Mare Imbrium, the dark area on the left, Mare Serenitatis at center, and Mare Crisium, the circular dark area to the right. Bright crater rim and ray deposits are from Copernicus, an impact crater 96 kilometers (60 miles) in diameter. Computer processing has exaggerated the brightness of poorly illuminated features near the day/night terminator in the polar regions, giving a false impression of high reflectivity there. The digital image processing was done by DLR the German aerospace research establishment near Munich, an international collaborator in the Galileo mission. The Galileo project, whose primary mission is the exploration of the Jupiter system in 1995-97, is managed for NASA's Office of Space Science and Applications by the Jet Propulsion Laboratory. |
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Moon - False Color Mosaic
PIA00131
Earth
Solid-State Imaging
| Title |
Moon - False Color Mosaic |
| Original Caption Released with Image |
This false-color mosaic was constructed from a series of 53 images taken through three spectral filters by Galileo's imaging system as the spacecraft flew over the northern regions of the Moon on December 7, 1992. The part of the Moon visible from Earth is on the left side in this view. The color mosaic shows compositional variations in parts of the Moon's northern hemisphere. Bright pinkish areas are highlands materials, such as those surrounding the oval lava-filled Crisium impact basin toward the bottom of the picture. Blue to orange shades indicate volcanic lava flows. To the left of Crisium, the dark blue Mare Tranquillitatis is richer in titanium than the green and orange maria above it. Thin mineral-rich soils associated with relatively recent impacts are represented by light blue colors, the youngest craters have prominent blue rays extending from them. The Galileo project, whose primary mission is the exploration of the Jupiter system in 1995-97, is managed for NASA's Office of Space Science and Applications by the Jet Propulsion Laboratory. |
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Moon - North Pole Mosaic
PIA00130
Earth
Solid-State Imaging
| Title |
Moon - North Pole Mosaic |
| Original Caption Released with Image |
This view of the Moon's north pole is a mosaic assembled from 18 images taken by Galileo's imaging system through a green filter as the spacecraft flew by on December 7, 1992. The left part of the Moon is visible from Earth, this region includes the dark, lava-filled Mare Imbrium (upper left), Mare Serenitatis (middle left), Mare Tranquillitatis (lower left), and Mare Crisium, the dark circular feature toward the bottom of the mosaic. Also visible in this view are the dark lava plains of the Marginis and Smythii Basins at the lower right. The Humboldtianum Basin, a 650-kilometer (400-mile) impact structure partly filled with dark volcanic deposits, is seen at the center of the image. The Moon's north pole is located just inside the shadow zone, about a third of the way from the top left of the illuminated region. |
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Moon Color Composite
PIA00113
Earth
Solid-State Imaging
| Title |
Moon Color Composite |
| Original Caption Released with Image |
This color image of the Moon was taken by the Galileo spacecraft at 9:35 a.m. PST Dec. 9, 1990, at a range of about 350,000 miles. The color composite uses monochrome images taken through violet, red, and near-infrared filters. The concentric, circular Orientale basin, 600 miles across, is near the center, the nearside is to the right, the far side to the left. At the upper right is the large, dark Oceanus Procellarum, below it is the smaller Mare Humorum. These, like the small dark Mare Orientale in the center of the basin, formed over 3 billion years ago as basaltic lava flows. At the lower left, among the southern cratered highlands of the far side, is the South-Pole-Aitken basin, similar to Orientale but twice as great in diameter and much older and more degraded by cratering and weathering. The cratered highlands of the near and far sides and the Maria are covered with scattered bright, young ray craters. |
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Gaspra - Highest Resolution
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PIA00118
Sol (our sun)
Solid-State Imaging
| Title |
Gaspra - Highest Resolution Mosaic |
| Original Caption Released with Image |
This picture of asteroid 951 Gaspra is a mosaic of two images taken by the Galileo spacecraft from a range of 5,300 kilometers (3,300 miles), some 10 minutes before closest approach on October 29, 1991. The Sun is shining from the right, phase angle is 50 degrees. The resolution, about 54 meters/pixel, is the highest for the Gaspra encounter and is about three times better than that in the view released in November 1991. Additional images of Gaspra remain stored on Galileo's tape recorder, awaiting playback in November. Gaspra is an irregular body with dimensions about 19 x 12 x 11 kilometers (12 x 7.5 x 7 miles). The portion illuminated in this view is about 18 kilometers (11 miles) from lower left to upper right. The north pole is located at upper left, Gaspra rotates counterclockwise every 7 hours. The large concavity on the lower right limb is about 6 kilometers (3.7 miles) across, the prominent crater on the terminator, center left, about 1.5 kilometers (1 mile). A striking feature of Gaspra's surface is the abundance of small craters. More than 600 craters, 100-500 meters (330-1650 feet) in diameter are visible here. The number of such small craters compared to larger ones is much greater for Gaspra than for previously studied bodies of comparable size such as the satellites of Mars. Gaspra's very irregular shape suggests that the asteroid was derived from a larger body by nearly catastrophic collisions. Consistent with such a history is the prominence of groove-like linear features, believed to be related to fractures. These linear depressions, 100-300 meters wide and tens of meters deep, are in two crossing groups with slightly different morphology, one group wider and more pitted than the other. Grooves had previously been seen only on Mars's moon Phobos, but were predicted for asteroids as well. Gaspra also shows a variety of enigmatic curved depressions and ridges in the terminator region at left. The Galileo project, whose primary mission is the exploration of the Jupiter system in 1995-97, is managed for NASA's Office of Space Science and Applications by the Jet Propulsion Laboratory. |
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Venus Colorized Clouds
PIA00111
Sol (our sun)
Solid-State Imaging
| Title |
Venus Colorized Clouds |
| Original Caption Released with Image |
This colorized picture of Venus was taken February 14, 1990, from a distance of almost 1.7 million miles, about 6 days after Galileo's closest approach to the planet. It has been colorized to a bluish hue to emphasize subtle contrasts in the cloud markings and to indicate that it was taken through a violet filter. Features in the sulfuric acid clouds near the top of the planet's atmosphere are most prominent in violet and ultraviolet light. This image shows the east-to-west-trending cloud banding and the brighter polar hoods familiar from past studies of Venus. The features are embedded in winds that flow from east to west at about 230 mph. The smallest features visible are about 45 miles across. An intriguing filamentary dark pattern is seen immediately left of the bright region at the subsolar point (equatorial 'noon'). North is at the top and the evening terminator is to the left. The Galileo Project is managed for NASA's Office of Space Science and Applications by the Jet Propulsion Laboratory, its mission is to study Jupiter and its satellites and magnetosphere after multiple gravity-assist flybys at Venus and Earth. |
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Asteroid Ida and Its Moon
PIA00136
Sol (our sun)
Solid-State Imaging
| Title |
Asteroid Ida and Its Moon |
| Original Caption Released with Image |
This is the first full picture showing both asteroid 243 Ida and its newly discovered moon to be transmitted to Earth from the National Aeronautics and Space Administration's (NASA's) Galileo spacecraft--the first conclusive evidence that natural satellites of asteroids exist. Ida, the large object, is about 56 kilometers (35 miles) long. Ida's natural satellite is the small object to the right. This portrait was taken by Galileo's charge-coupled device (CCD) camera on August 28, 1993, about 14 minutes before the Jupiter-bound spacecraft's closest approach to the asteroid, from a range of 10,870 kilometers (6,755 miles). Ida is a heavily cratered, irregularly shaped asteroid in the main asteroid belt between Mars and Jupiter--the 243rd asteroid to be discovered since the first was found at the beginning of the 19th century. Ida is a member of a group of asteroids called the Koronis family. The small satellite, which is about 1.5 kilometers (1 mile) across in this view, has yet to be given a name by astronomers. It has been provisionally designated '1993 (243) 1' by the International Astronomical Union. ('1993' denotes the year the picture was taken, '243' the asteroid number and '1' the fact that it is the first moon of Ida to be found.) Although appearing to be 'next' to Ida, the satellite is actually in the foreground, slightly closer to the spacecraft than Ida is. Combining this image with data from Galileo's near-infrared mapping spectrometer, the science team estimates that the satellite is about 100 kilometers (60 miles) away from the center of Ida. This image, which was taken through a green filter, is one of a six-frame series using different color filters. The spatial resolution in this image is about 100 meters (330 feet) per pixel. |
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Craters near the south pole
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PIA00876
Jupiter
Solid-State Imaging
| Title |
Craters near the south pole of Callisto |
| Original Caption Released with Image |
This image of the south polar region of the Jovian satellite Callisto was taken in twilight by the Galileo spacecraft on its eighth orbit around Jupiter. Craters ranging in size from 60 kilometers (36 miles) down to the limit of resolution are visible in this image. Scientists count the number of craters on a planetary surface to estimate its relative (and sometimes absolute) age. Note that many of the craters are not as sharp in appearance as the two large craters near the bottom of the image. This is an indication that some process has eroded the craters since their formation. This image is centered at 82.5 south latitude and 62.6 west longitude, and covers an area approximately 370 kilometers (220 miles) by 280 kilometers (170 miles). North is toward the top of the image. This image was taken on May 6, 1997 by the Solid State Imaging system (CCD) on board NASA's Galileo spacecraft at a resolution of 676 meters (417 feet) per picture element. 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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Callisto Scarp Mosaic
PIA00561
Jupiter
Solid-State Imaging
| Title |
Callisto Scarp Mosaic |
| Original Caption Released with Image |
This mosaic of two images shows an area within the Valhalla region on Jupiter's moon, Callisto. North is to the top of the mosaic and the Sun illuminates the surface from the left. The smallest details that can be discerned in this picture are knobs and small impact craters about 155 meters (170 yards) across. The resolution is 46 meters (50 yards) per picture element, and the mosaic covers an area approximately 33 kilometers (20 miles) across. A prominent fault scarp crosses the mosaic. This scarp is one of many structural features that form the Valhalla multi-ring structure, which has a diameter of 4,000 kilometers (2,485 miles). Scientists believe Valhalla is the result of a large impact early in the history of Callisto. Several smaller ridges are found parallel to the prominent scarp. Numerous impact craters ranging in size from 155 meters (170 yards) to 2.5 kilometers (1.5 miles) are seen in the mosaic. The images which form this mosaic were obtained by the solid state imaging system aboard NASA's Galileo spacecraft on Nov. 4, 1996 (Universal Time). 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 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. |
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Callisto Crater Chain at Hig
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PIA00581
Jupiter
Solid-State Imaging
| Title |
Callisto Crater Chain at High Resolution Shown in Context |
| Original Caption Released with Image |
A portion of a chain of impact craters on Jupiter's moon Callisto is seen in this image taken by the Galileo spacecraft on November 4, 1996. This crater chain on Callisto is believed to result from the impact of a split object, similar to the fragments of Comet Shoemaker-Levy 9 which smashed into Jupiter's atmosphere in July of 1994. This high-resolution view, taken by Galileo's solid state imaging television camera during its third orbit around Jupiter, is of Callisto's northern hemisphere at 35 degrees north, 46 degrees west, and covers an area of about eight miles (13 kilometers) across. The smallest visible crater is about 140 yards (130 meters) across. The image was taken at a range of 974 miles (1,567 kilometers). On a global scale, Callisto is heavily cratered, indicating the great age of its surface. At the scale of this image, it was anticipated that the surface would be heavily cratered as well, however, there is a surprising lack of small craters, suggesting that one or more processes have obliterated these and other small-scale features. For example, downslope movement of ice-rich debris could bury small craters. The bright slopes visible in this picture represent places where downslope movement has taken place, exposing fresh ice surfaces. 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. |
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Callisto Crater Chain Mosaic
PIA00549
Jupiter
Solid-State Imaging
| Title |
Callisto Crater Chain Mosaic |
| Original Caption Released with Image |
This mosaic of three images shows an area within the Valhalla region on Jupiter's moon, Callisto. North is to the top of the mosaic and the Sun illuminates the surface from the left. The smallest details that can be discerned in this picture are knobs and small impact craters about 160 meters (175 yards) across. The mosaic covers an area approximately 45 kilometers (28 miles) across. It shows part of a prominent crater chain located on the northern part of the Valhalla ring structure. Crater chains can form from the impact of material ejected from large impacts (forming secondary chains) or by the impact of a fragmented projectile, perhaps similar to the Shoemaker-Levy 9 cometary impacts into Jupiter in July 1994. It is believed this crater chain was formed by the impact of a fragmented projectile. The images which form this mosaic were obtained by the solid state imaging system aboard NASA's Galileo spacecraft on Nov. 4, 1996 (Universal Time). 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 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. |
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Callisto's Varied Crater Lan
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PIA01632
Jupiter
Solid-State Imaging
| Title |
Callisto's Varied Crater Landscape |
| Original Caption Released with Image |
This portion of the surface of Callisto, Jupiter's second largest moon, contains an immensely varied crater landscape. A large, degraded crater dominates the southern (bottom) portion of the image. There are fresh to highly degraded craters at all sizes, but a relatively low number of small, fresh craters. A diagonal "trench" cuts across a crater rim in the north (top) of the image. Several clusters of small craters appear throughout the image. Images revealing the appearance and numbers of craters, help establish which erosional processes take place on a planet's surface, and help determine a relative age for the surface. North is to the top of the picture. The image, centered at 13.4 degrees north latitude and 141.8 degrees west longitude, covers an area approximately 61 kilometers (38 miles) by 60 kilometers (37 miles). The resolution is about 85 meters (280 feet) per picture element. The horizontal black lines indicate gaps in the data received for this image. The image was taken on September 17th, 1997 at a range of 8400 kilometers (5200 miles) by the Solid State Imaging (SSI) system on NASA's Galileo spacecraft during its tenth orbit of Jupiter. 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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The Valhalla Multi-ring Stru
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PIA01649
Jupiter
Solid-State Imaging
| Title |
The Valhalla Multi-ring Structure on Callisto |
| Original Caption Released with Image |
These images of Callisto, the outermost of the Galilean satellites of Jupiter, reveal a surface characterized by impact craters. The global view (lower left) is dominated by a large bulls-eye feature, the Valhalla multi-ring structure, consisting of a bright inner region about 600 kilometers (370 miles) across. Valhalla's 4,000 kilometer(2,500 mile) diameter make it one of the largest impact features in the solar system. Callisto is 4,800 kilometers (3,000 miles) in diameter. In this global view, the sun illuminates the surface from near the center, in the same way a full moon is seen from Earth when illuminated by the sun. The image on the right shows part of Valhalla at moderate resolution. At this resolution, the surface is appears to be somewhat smooth, with a lack of numerous small impact craters. Valhalla's outer rings are clearly seen to consist of troughs which could be fractures in the crust which resulted from the impact. The bright central plains possibly were created by the excavation and ejection of "cleaner" ice or liquid water from beneath the surface, with a fluid-like massfilling the crater bowl after impact. North is to the top of the picture. For the moderate resolution view on the right, the sun illuminates the surface from the left and the resolution is approximately 400 meters per picture element. The images were obtained on June 25, 1997 by the solid state imaging (SSI)system on NASA's Galileo spacecraft at a range of about 40,000 kilometers(25,000 miles) from Callisto during Galileo's ninth orbit of Jupiter. The global image on the left is centered at 0.5 degrees south latitude and 56 degrees longitude. The resolution is 14 kilometers per picture element. The images were obtained on November 5, 1997 at a range of 68,400 kilometers(42,400 miles) during Galileo's eleventh orbit of Jupiter. 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 URLhttp://galileo.jpl.nasa.gov [ http://galileo.jpl.nasa.gov ]. Background information and educational context for the images can be found at URLhttp://www.jpl.nasa.gov/galileo/sepo [ http://www.jpl.nasa.gov/galileo/sepo ] |
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Callisto: Pits or Craters?
PIA01630
Jupiter
Solid-State Imaging
| Title |
Callisto: Pits or Craters? |
| Original Caption Released with Image |
This image of Jupiter's second largest moon, Callisto, presents one of the mysteries discovered by NASA's Galileo spacecraft. In the upper left corner of the image, what appear to be very small craters are visible (See enlargement.) on the floors of some larger craters as well as in the area immediately adjacent to the larger craters. Some these smaller craters are not entirely circular. They are very similar to a population of unclassified "pits" seen in one Callisto mosaic [ http://photojournal.jpl.nasa.gov/catalog/PIA00745 ] from Galileo's ninth orbit. One possible explanation for the pits is that they represent a class of previously unseen endogenic (formed by some surface or subsurface process, rather than an impact) features. Another explanation is that they are partially eroded secondary craters. Secondary craters are formed when an initial large impact ejects large enough pieces of the surface that the pieces themselves create small craters. By studying the orientation of the pits and clusters of small craters relative to larger impacts, as well as carefully examining the physical appearance of the two groups, scientists hope to discover the origin of the pits, and the possible relationship they may have with small craters. North is to the top of the picture, and the sun illuminates the surface from the right. The full image, centered at 20.5 degrees north latitude and 142.2 degrees west longitude, covers an area approximately 72 kilometers (45 miles) by 55 kilometers (34) miles. The resolution is about 90 meters (295 feet) per picture element. The image was taken on September 17th, 1997 at a range of 8800 kilometers (5460 miles) by the Solid State Imaging (SSI) system on NASA's Galileo spacecraft during its tenth orbit of Jupiter. 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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Impact Craters on Icy Callis
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PIA01648
Jupiter
Solid-State Imaging
| Title |
Impact Craters on Icy Callisto: Doh crater and Asgard |
| Original Caption Released with Image |
This composite of Jupiter's icy moon Callisto combines data from two orbits showing several types of impact craters. North is to the top of the picture, the sun illuminates the surface from the east. The global image on the right shows one of the largest impact structures on Callisto, the Asgard multi-ring structure located near 30 degrees north latitude, 142 degrees west longitude. The Asgard structure is approximately 1700 kilometers (1,054 miles) across and consists of a bright central zone surrounded by discontinuous rings. The rings include degraded ridges near the central zone and troughs at the outer margin, which resulted from deformation of the icy crust following impact. Smaller impacts have smashed into Callisto after the formation of Asgard. The young, bright-rayed crater Burr located on the northern part of Asgardis about 75 kilometers (46 miles) across. Galileo images show a third type of impact crater in this image, a dome crater named Doh, located in the bright central plains of Asgard. Doh (left image) is about 55 kilometers (34 miles)in diameter, while the dome is about 25 kilometers (15 miles) across. Dome craters contain a central mound instead of a bowl shaped depression or central mountain (peak) typically seen in larger impact craters. This type of crater could represent penetration into a slushy zone beneath the surface of the Asgard impact. The global image on the right was taken on November 4, 1996, at a distance of 111,900 kilometers (69,400 miles) by the solid state imaging (SSI) camera onboard NASA's Galileo spacecraft during its third orbit around Jupiter. The image on the left was obtained at a resolution of 90 meters (295 feet)per picture element on September 16, 1997 during Galileo's tenth orbit when the spacecraft was less than 9,500 kilometers (6,000 miles) from Callisto. 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 URLhttp://galileo.jpl.nasa.gov [ http://galileo.jpl.nasa.gov ]. Background information and educational context for the images can be found at URLhttp://www.jpl.nasa.gov/galileo/sepo [ http://www.jpl.nasa.gov/galileo/sepo ] |
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So few Small Craters on Call
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PIA01631
Jupiter
Solid-State Imaging
| Title |
So few Small Craters on Callisto |
| Original Caption Released with Image |
This moderately high resolution view of Jupiter's icy moon, Callisto, shows two, probably related, phenomena that were quite surprising to planetary scientists. First, a dark, mobile blanket of material covers Callisto's surface. Movement of this material occurs on slopes, as seen here on some crater walls. Second, while Callisto has a significant number of large craters, it lacks the related number of small craters which are seen in the crater size distributions of other similar bodies in our solar system. Small craters near slopes would become filled in by the downward movement of the dark material, but what erases the other small craters? One alternative is that the population of potential impactors around Jupiter has fewer small objects than previously expected. North is to the top of the picture. The image, centered at 17.5 degrees north latitude and 142.1 degrees west longitude, covers an area approximately 74 kilometers (46 miles) by 75 kilometers (47 miles). The resolution is about 87 meters (285 feet) per picture element. The image was taken on September 17th, 1997 at a range of 8600 kilometers (5330 miles) by the Solid State Imaging (SSI) system on NASA's Galileo spacecraft during its tenth orbit of Jupiter. 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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Jupiter's Main Ring
PIA00657
Jupiter
Solid-State Imaging
| Title |
Jupiter's Main Ring |
| Original Caption Released with Image |
A mosaic of four images taken through the clear filter (610 nanometers) of the solid state imaging (CCD) system aboard NASA's Galileo spacecraft on November 8, 1996, at a resolution of approximately 46 kilometers (km) per picture element (pixel) along the rings, however, because the spacecraft was only about 0.5 degrees above the ring plane, the image is highly foreshortened in the vertical direction. The images were obtained when Galileo was in Jupiter's shadow peering back toward the Sun, the ring was approximately 2,300,000 kilometers (km) away. The arc on the far right of the image is produced by sunlight scattered by small particles comprising Jupiter's upper atmospheric haze. The ring also efficiently scatters light, indicating that much of its brightness is due to particles that are microns or less in diameter. Such small particles are believed to have human-scale lifetimes, i.e., very brief compared to the solar system's age. Jupiter's ring system is composed of three parts -- a flat main ring, a lenticular halo interior to the main ring, and the gossamer ring, which lies exterior to the main ring. The near and far arms of Jupiter's main ring extend horizontally across the mosaic, joining together at the ring's ansa, on the far left side of the figure. The near arm of the ring appears to be abruptly truncated close to the planet, at the point where it passes into Jupiter's shadow. Some radial structure is barely visible across the ring's ansa. A faint mist of particles can be seen above and below the main rings, this vertically extended "halo" is unusual in planetary rings, and is probably caused by electromagnetic forces pushing the smallest grains out of the ring plane. Because of shadowing, the halo is not visible close to Jupiter in the lower right part of the mosaic. Jupiter's main ring is a thin strand of material encircling the planet. The diffuse innermost boundary begins at approximately 123,000 km. The main ring's outer radius is found to be at 128,940 +/-50 km, slightly less than the Voyager value of 129,130 +/-100 km, but very close to the orbit of the satellite Adrastea (128,980 km). The main ring exhibits a marked drop in brightness at 127,849 +/-50 km, lying almost atop the orbit of the Jovian moon Metis at 127,978 km. Satellites seem to affect the structure of even tenuous rings like that found at Jupiter. 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: 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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Jupiter's Ring Halo
PIA00658
Jupiter
Solid-State Imaging
| Title |
Jupiter's Ring Halo |
| Original Caption Released with Image |
A mosaic of four images taken through the clear filter (610 nanometers) of the solid state imaging (CCD) system aboard NASA's Galileo spacecraft on November 8, 1996, at a resolution of approximately 46 kilometers (km) per picture element (pixel) along the rings, however, because the spacecraft was only about 0.5 degrees above the ring plane, the image is highly foreshortened in the vertical direction. The images were obtained when Galileo was in Jupiter's shadow peering back toward the Sun, the ring was approximately 2,300,000 kilometers (km) away. The arc on the far right of the image is produced by sunlight scattered by small particles comprising Jupiter's upper atmospheric haze. The ring also efficiently scatters light, indicating that much of its brightness is due to particles that are microns or less in diameter. Such small particles are believed to have human-scale lifetimes, i.e., very brief compared to the solar system's age. Jupiter's ring system is composed of three parts -- a flat main ring, a lenticular halo interior to the main ring, and the gossamer ring, which lies exterior to the main ring. The near and far arms of Jupiter's main ring extend horizontally across the mosaic, joining together at the ring's ansa, on the far left side of the figure. The near arm of the ring appears to be abruptly truncated close to the planet, at the point where it passes into Jupiter's shadow. A faint mist of particles can be seen above and below the main rings, this vertically extended, toroidal "halo" is unusual in planetary rings, and is probably caused by electromagnetic forces which can push small grains out of the ring plane. Halo material is present across this entire image, implying that it reaches more than 27,000 km above the ring plane. Because of shadowing, the halo is not visible close to Jupiter in the lower right part of the mosaic. In order to accentuate faint features in the image, different brightnesses are shown through color, with the brightest being white or yellow and the faintest purple. 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: 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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Moderate-resolution view of
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PIA00898
Jupiter
Solid-State Imaging
| Title |
Moderate-resolution view of Callisto's surface |
| Original Caption Released with Image |
This five-frame mosaic of the Jovian satellite Callisto shows a surface densely populated with impact craters. However, close inspection of this image reveals differences among the craters. For example, a few of the craters contain central dome-shaped features, while others contain depressions, or pits, within the crater floor. Scientists study differences among craters such as these to learn more about both the surface that was struck by an impactor, and the impactor itself. These images were obtained by the Galileo spacecraft on its eighth orbit around Jupiter at a distance of 48,000 km from Callisto. The mosaic is centered at 31 S. latitude and 122 W. longitude, and covers an area approximately 700 kilometers (420 miles) by 900 kilometers (540 miles)-- somewhat larger than Montana. The finest details that can be discerned in this picture are about 1.8 kilometers across (0.93 km/pixel). 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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Global Callisto in Color
PIA03456
Jupiter
Solid-State Imaging
| Title |
Global Callisto in Color |
| Original Caption Released with Image |
Bright scars on a darker surface testify to a long history of impacts on Jupiter's moon Callisto in this image of Callisto from NASA's Galileo spacecraft. The picture, taken in May 2001, is the only complete global color image of Callisto obtained by Galileo, which has been orbiting Jupiter since December 1995. Of Jupiter's four largest moons, Callisto orbits farthest from the giant planet. Callisto's surface is uniformly cratered but is not uniform in color or brightness. Scientists believe the brighter areas are mainly ice and the darker areas are highly eroded, ice-poor material. 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. Additional information about the spacecraft and its discoveries is available on the Galileo home page at http://galileo.jpl.nasa.gov [ http://galileo.jpl.nasa.gov ]. |
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Callisto's Equatorial Region
PIA00745
Jupiter
Solid-State Imaging
| Title |
Callisto's Equatorial Region |
| Original Caption Released with Image |
This mosaic covers part of the equatorial region of Jupiter's moon, Callisto. The mosaic combines six separate image frames obtained by the solid state imaging (CCD) system on NASA's Galileo spacecraft during its ninth orbit around Jupiter. North is to the top of the picture. The mosaic shows several new features and characteristics of the surface revealed by Galileo. These include deposits that may represent landslides in the southern and southwestern floors of many craters. Two such deposits are seen in a 12 kilometer (7.3 mile) crater in the west-central part of the image, and in a 23 kilometer (14 mile) crater just north of the center of the image. Also notable are several sinuous valleys emanating from the southern rims of 10 to 15 kilometer (6.2 to 9.3 mile) irregular craters in the west-central part of the image. The pervasive local smoothing of Callisto's surface is well represented in the plains between the craters in the southeastern part of the image. Possible oblique impacts are suggested by the elongated craters in the northeastern and southeastern parts of the image. The mosaic, centered at 7.4 degrees south latitude and 6.6 degrees west longitude, covers an area of approximately 315 by 215 kilometers (192 by 131 miles). The sun illuminates the scene from the west (left). The smallest features that can be seen are about 300 meters (993 feet) across. The images were obtained on June 25, 1997, when the spacecraft was at a range of 15,200 kilometers (8,207 miles) from Callisto. 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. Background information and educational context for the images can be found at URL http://www.jpl.nasa.gov/galileo/sepo |
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The Asgard Hemisphere of Cal
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PIA01100
Jupiter
Solid-State Imaging
| Title |
The Asgard Hemisphere of Callisto |
| Original Caption Released with Image |
False color view of a portion of the leading hemisphere of Jupiter's moon Callisto as seen through the infrared filters of the Solid State Imaging (CCD) system aboard NASA's Galileo spacecraft. North is to the top of the picture and the sun illuminates the surface from the east. More recent impacts have excavated bright, relatively clean ice from beneath Callisto's battered surface. Callisto's dark mottled appearance may be due to contamination by non-ice components contributed by impactors or concentrated in a residue as ice is removed. This color composite image is centered on longitude 139 West and encompasses an area about 1000 miles (1600 kilometers) by 2470 miles (4000 kilometers). The images were obtained on November 3rd, 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 |
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Compositional Variations in
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PIA01128
Jupiter
Solid-State Imaging
| Title |
Compositional Variations in Callisto's Asgard Impact Structure |
| Original Caption Released with Image |
These frames combine data from two of the instruments aboard NASA's Galileo spacecraft. The left image is from the Solid State Imaging (SSI) system and the right frame shows data from the Near Infrared Mapping Spectrometer (NIMS) overlaid on the SSI data. North is to the top of the images. The area to the northeast (upper right corner) of the NIMS observation shows the southwest part of the ancient impact structure Asgard [ http://photojournal.jpl.nasa.gov/catalog/PIA00517 ] on Jupiter's moon Callisto. The Asgard multi-ring system has a central bright zone approximately 230 km (140 miles) across, surrounded by concentric rings out to 800 km (480 miles). The rings are fractured parts of the surface with scarps near the central zone and troughs at the outer margin. Impact craters ranging in size down to the limit of resolution are visible throughout the image. The NIMS observation of a small section of the Asgard terrain reveals compositional variations over the surface of Callisto. Red indicates a high concentration of clean ice at the floor of an impact crater while blue shows large amounts of non-ice material on the surrounding surface. The data in these images were taken on November 4, 1996, at a distance of 111,891 kilometers (69,900 miles) by the Solid State Imaging (CCD) system and 17,920 kilometers (11,200 miles) by the Near Infrared Mapping Spectrometer aboard NASA's Galileo spacecraft during its third orbit around Jupiter. The area seen in the SSI image is 440 kilometers by 440 kilometers across at 1.1 kilometers per picture element (pixel) resolution, centered near 17 North, 153 West, while the resolution for the NIMS observation is 8 kilometers per pixel. 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://www.jpl.nasa.gov/ galileo. |
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Interior of Callisto
PIA01131
Jupiter
Solid-State Imaging
| Title |
Interior of Callisto |
| Original Caption Released with Image |
Cutaway view of the possible internal structure of Callisto. The surface of the satellite is a mosaic of images obtained in 1979 by NASA's Voyager spacecraft. The interior characteristics are inferred from gravity field and magnetic field measurements by NASA's Galileo spacecraft. Callisto's radius is 2403 km, larger than our Moon's radius. Callisto's interior is shown as a relatively uniform mixture of comparable amounts of ice and rock. The surface layer of Callisto is shown as white to indicate that it may differ from the underlying ice/rock layer in a variety of ways including, for example, the percentage of rock it contains. 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://www.jpl.nasa.gov/ galileo. |
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Jupiter's Main Ring/Ring Hal
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PIA00701
Jupiter
Solid-State Imaging
| Title |
Jupiter's Main Ring/Ring Halo |
| Original Caption Released with Image |
A mosaic of four images taken through the clear filter (610 nanometers) of the solid state imaging (CCD) system aboard NASA's Galileo spacecraft on November 8, 1996, at a resolution of approximately 46 kilometers (28.5 miles) per picture element (pixel) along Jupiter's rings. Because the spacecraft was only about 0.5 degrees above the ring plane, the image is highly foreshortened in the vertical direction. The images were obtained when Galileo was in Jupiter's shadow, peering back toward the Sun, the ring was approximately 2.3 million kilometers (1.4 million miles) away. The arc on the far right of the image is produced when sunlight is scattered by small particles comprising Jupiter's upper atmospheric haze. The ring also efficiently scatters light, indicating that much of its brightness is due to particles that are microns or less in diameter. Such small particles are believed to have human-scale lifetimes, i.e., very brief compared to the solar system's age. Jupiter's ring system is composed of three parts - - a flat main ring, a lenticular halo interior to the main ring, and the gossamer ring, outside the main ring. The near and far arms of Jupiter's main ring extend horizontally across the mosaic, joining together at the ring's ansa, on the figure's far left side. The near arm of the ring appears to be abruptly truncated close to the planet, at the point where it passes into Jupiter's shadow. Some radial structure is barely visible across the ring's ansa (top image). A faint mist of particles can be seen above and below the main rings. This vertically extended "halo" is unusual in planetary rings, and is probably caused by electromagnetic forces pushing the smallest grains out of the ring plane. Because of shadowing, the halo is not visible close to Jupiter in the lower right part of the mosaic. To accentuate faint features in the bottom image of the ring halo, different brightnesses are shown through color. Brightest features are white or yellow and the faintest are purple. Jupiter's main ring is a thin strand of material encircling the planet. The diffuse innermost boundary begins at approximately 123,000 kilometers (76,429 miles). The main ring's outer radius is found to be at 128,940 kilometers (80,119 miles) +/-50 kilometers (31 miles), slightly less than the Voyager value of 129,130 kilometers (80,237 miles) +/-100 kilometers (62 miles), but very close to the orbit of the satellite Adrastea (128,980 kilometers or 80,144 miles). The main ring exhibits a marked drop in brightness at 127,849 kilometers (79,441 miles) +/-50 kilometers (31 miles), lying almost atop the orbit of the Jovian moon Metis at 127,978 kilometers (79,521 miles). Satellites seem to affect the structure of even tenuous rings like those found at 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 |
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Fine Details of the Icy Surf
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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 |
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View of Callisto from Voyage
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PIA01055
Jupiter
Solid-State Imaging
| Title |
View of Callisto from Voyager and Galileo |
| Original Caption Released with Image |
View of Callisto, most distant of the four large moons of Jupiter. This mosaic was prepared from images obtained by three spacecraft: Voyager 1 (left side), Galileo (middle), and Voyager 2 data (right side). The Voyager data were taken in 1979 but left a "gap" centered at longitude 290 degrees in the trailing hemisphere of Callisto. The Galileo Solid-State Imaging system photographed this area on its second orbit around Jupiter on 9 September, 1996 Universal Time. The resolution of the Galileo data is 4.3 kilometers/pixel (2.7 miles), meaning that the smallest visible feature is about 12 kilometers (7 miles) across. North is to the top of the picture. Features of interest in the new Galileo data include a dark, smooth area in the northern latitudes (upper third) which appears to mantle older terrain. This could be dark ejecta from a small impact crater. Also visible is a fresh, sharp-rimmed crater some 90 km (56 miles) across named Igaluk (center left third of picture), and a bright zone in the south polar area (bottom of image) which could be an impact scar. 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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Har Crater on Callisto
PIA01054
Jupiter
Solid-State Imaging
| Title |
Har Crater on Callisto |
| Original Caption Released with Image |
This image shows a heavily cratered region near Callisto's equator. It was taken by the Galileo spacecraft Solid State Imaging (CCD) system on its ninth orbit around Jupiter. North is to the top of the image. The 50 kilometer (30 mile) double ring crater in the center of the image is named Har. Har displays an unusual rounded mound on its floor. The origin of the mound is unclear but probably involves uplift of ice-rich materials from below, either as a "rebound" immediately following the impact that formed the crater or as a later process. Har is older than the prominent 20 kilometer (12 mile) crater superposed on its western rim. The large crater partially visible in the northeast corner of the image is called Tindr. Chains of secondary craters (craters formed from the impact of materials thrown out of the main crater during an impact) originating from Tindr crosscut the eastern rim of Har. The image, centered at 3.3 degrees south latitude and 357.9 degrees west longitude, covers an area of 120 kilometers by 115 kilometers (75 miles by 70 miles). The sun illuminates the scene from the west (left). The smallest distinguishable features in the image are about 294 meters (973 feet) across. This image was obtained on June 25, 1997, when Galileo was 14,080 kilometers (8,590 miles) from Callisto. 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. |
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Large impact on Callisto`s s
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PIA01077
Jupiter
Solid-State Imaging
| Title |
Large impact on Callisto`s southern hemisphere |
| Original Caption Released with Image |
This mosaic of images showing a large 200 kilometer (120 mile) diameter impact crater on Callisto's southern hemisphere was obtained by the solid state imaging (CCD) system on board NASA's Galileo spacecraft during its eighth orbit of Jupiter. This crater is characterized by a bright circular area surrounded by a darker material excavated and ejected by the impact. Beyond this is a zone of rays which are oriented radially outward and contain material also thrown from the crater. Fewer smaller impact craters are visible in the ejecta blanket surrounding the large crater than in the areas more distant from the crater. This lack of craters superposed on the ejecta blanket and on the crater itself, together with the brightness of the central zone, is evidence that the large crater is a relatively young feature on Callisto. Scientists use information such as the number of craters in a given area together with the principle of superposition (in which younger landforms are "on top" of older features) to determine the relative ages of features and terrains. North is to the top of the mosaic with the sun illuminating the surface from the left. The mosaic, centered at 55 degrees south latitude and 30 degrees west longitude, covers an area approximately 1400 kilometers (850 miles) by 1235 kilometers (740 miles), at a resolution of 867 meters (945 yards) per picture element. The images which make up this mosaic were taken on May 6, 1997, from an altitude of approximately 43,000 kilometers (26,000 miles) above the surface of Callisto. 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. Background information and educational context for the images can be found at URL http://www.jpl.nasa.gov/galileo/sepo |
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Resurfacing of the Jupiter-f
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PIA00712
Jupiter
Solid-State Imaging
| Title |
Resurfacing of the Jupiter-facing hemisphere of Io |
| Original Caption Released with Image |
Four views of the hemisphere of Io which faces Jupiter showing changes seen on June 27th, 1996 by the Galileo spacecraft as compared to views seen by the Voyager spacecraft during the 1979 flybys. Clockwise from upper left is a Voyager 1 high resolution image, a Voyager 1 color image, a Galileo color image, and a Voyager 2 color image. North is to the top of the picture. Voyager and Galileo images have been adjusted to provide comparable color balances similar to Voyager color. The most dramatic changes between Voyagers 1 and 2, just 4 months apart, were the effects of the eruptions of Surt (latitude +45 degrees) and Aten Patera (latitude -48 degrees) which darkened the caldera floors and left diffuse pyroclastic deposits covering areas about 1400 km in diameter (about the size of Alaska). In the Galileo image the Surt and Aten regions appear much more similar to the Voyager 1 pre-eruption images than to the Voyager 2 images. The plume deposits appear to have largely 'faded away' and the calderas have brightened. The Surt and Aten plume deposits had spectral properties similar to the plume deposits of Pele. Pele's deposits have not faded, suggesting that Pele had remained intermittently active whereas Surt and Aten are only rarely active. 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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Landslides on Callisto
PIA01095
Jupiter
Solid-State Imaging
| Title |
Landslides on Callisto |
| Original Caption Released with Image |
Recent Galileo images of the surface of Jupiter's moon Callisto have revealed large landslide deposits within two large impact craters seen in the right side of this image. The two landslides are about 3 to 3.5 kilometers (1.8 to 2.1 miles) in length. They occurred when material from the crater wall failed under the influence of gravity, perhaps aided by seismic disturbances from nearby impacts. These deposits are interesting because they traveled several kilometers from the crater wall in the absence of an atmosphere or other fluids which might have lubricated the flow. This could indicate that the surface material on Callisto is very fine-grained, and perhaps is being "fluffed" by electrostatic forces which allowed the landslide debris to flow extended distances in the absence of an atmosphere. This image was acquired on September 16th, 1997 by the Solid State Imaging (CCD) system on NASA's Galileo spacecraft, during the spacecraft's tenth orbit around Jupiter. North is to the top of the image, with the sun illuminating the scene from the right. The center of this image is located near 25.3 degrees north latitude, 141.3 degrees west longitude. The image, which is 55 kilometers (33 miles) by 44 kilometers (26 miles) across, was acquired at a resolution of 100 meters per picture element. 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. |
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Unusual Volcanic Pyroclastic
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PIA00711
Jupiter
Solid-State Imaging
| Title |
Unusual Volcanic Pyroclastic Deposits on Io |
| Original Caption Released with Image |
Four views of Euboea Fluctus on Jupiter's moon Io showing changes seen on June 27th, 1996 by the Galileo spacecraft as compared to views seen by the Voyager spacecraft during the 1979 flybys. Clockwise from upper left is a Voyager 1 high resolution image, a Galileo enhanced color image, a Galileo image with simulated Voyager colors, and a Voyager 2 color image. North is to the top of the picture. The Galileo images show new diffuse deposits which have an unusual morphology for plume deposits. A diffuse yellowish deposit with a radius of 285 km extends to the northwest, whereas an intense reddish deposit marks a curving fallout margin to the southeast. This morphology may have resulted from the presence of a topographic obstruction to southeast of the vent. 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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Io Eclipse/Volcanic Eruption
PIA00704
Sol (our sun)
Solid-State Imaging
| Title |
Io Eclipse/Volcanic Eruption |
| Original Caption Released with Image |
This image was acquired while Io was in eclipse (in Jupiter's shadow) during Galileo's eighth orbit, and reveals several dynamic processes. The most intense features are red, while glows of lesser intensity are yellow or green, and very faint glows appear blue in this color-coded image. The small red or yellow spots mark the sites of high-temperature magma erupting onto the surface in lava flows or lava lakes. This image reveals a field of bright spots near Io's sub-Jupiter point (right-hand side of image). The sub-Jupiter hemisphere always faces Jupiter just as the Moon's nearside always faces Earth. There are extended diffuse glows on the equatorial limbs or edges of the planet (right and left sides). The glow on the left is over the active volcanic plume Prometheus, but whereas Prometheus appears to be 75 kilometers (46.6 miles) high in reflected light, here the diffuse glow extends about 800 kilometers (497 miles) from Io's limb. This extended glow indicates that gas or small particles reach much greater heights than the dense inner plume. The diffuse glow on the right side reaches a height of 400 kilometers (249 miles), and includes a prominence with a plume-like shape. However, no volcanic plume has been seen at this location in reflected light. This type of observation is revealing the relationships between Io's volcanism, atmosphere and exosphere. Taken on May 6, 1997, north is toward the top. The image was taken with the clear filter of the solid state imaging (CCD) system on NASA's Galileo spacecraft at a range of 1.8 million kilometers (1.1 million miles). 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 |
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Large Craters in Callisto's
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PIA01219
Jupiter
Solid-State Imaging
| Title |
Large Craters in Callisto's Southern Hemisphere |
| Original Caption Released with Image |
NASA's Galileo spacecraft provides a new view of this heavily cratered region in the southern hemisphere of the icy Jovian satellite Callisto. The region was not observed by NASA's Voyager spacecraft. Craters ranging in diameter from the 1.85 kilometer (1.13 mile) limit of resolution up to more than 70 kilometers (43 miles) can be observed in this image. Although all craters are generally round in outline, details in their structures vary with both size and relative age. Bright spots in the center of smaller craters (up to approximately 20 kilometers (12 miles)) are central peaks. Larger craters (up to the 51 kilometer (31 mile) wide crater in the east central part of the image) exhibit central pits or depressions. The largest crater, called Thrainn, has a diameter of 74 kilometers (45 miles) and is located in the southernmost corner of the image. This crater contains a broad central uplift, or dome, and has a highly eroded rim. In contrast, the 70 kilometer (43 mile) crater Audr, located along the northern margin of the image, is flat-bottomed, and has a less degraded and generally rounder rim. If erosional or degradational forces have been roughly constant with time on Callisto, scientists viewing this image can assume that Audr is relatively younger than Thrainn by noting the less degraded or fresher appearance of its rim. The differences in crater floor features between these two similarly sized craters could have been produced by differences in the impacting bodies that produced them, differences in the crustal materials in which the craters formed, or simply by a gradual evolution of crater floor shape with time. North is to the top of the image which was taken by the Galileo spacecraft's solid state imaging (CCD) system during its eighth orbit around Jupiter on May 6th, 1997. The center of the image is located at 34 degrees south latitude, 84 degrees west longitude, and was taken when the spacecraft was approximately 48,430 kilometers (29,542 miles) from Callisto. 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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Heavy Cratering near Callist
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PIA01221
Jupiter
Solid-State Imaging
| Title |
Heavy Cratering near Callisto's South Pole |
| Original Caption Released with Image |
Images from NASA's Galileo spacecraft provide new insights into this region near Callisto's south pole. This two frame mosaic shows a heavily cratered surface with smooth plains in the areas between craters. North is to the top of the image. The smoothness of the plains appears to increase toward the south pole, approximately 480 kilometers (293 miles) south of the bottom of the image. This smoothness of Callisto's surface was not evident in images taken during the 1979 flyby of NASA's Voyager spacecraft because the resolution was insufficient to show the effect. This smooth surface, and the process(es) that cause it, are among the most intriguing aspects of Callisto. Although not fully understood, the process(es) responsible for this smoothing could include erosion by tiny meteorites and energetic ions. Some craters, such as Keelut, the 47 kilometer (29 mile) crater in the lower right corner, have sharp, well defined rims. Keelut contains an inner ring surrounding a central depression about 17 kilometers (11 miles) in diameter. Keelut, and the more irregularly shaped, degraded Reginleif, the 32 kilometer (19.5 mile) crater in the top center of the image, are very shallow and have flat floors. Crater forms can be seen down to less than 2 kilometers (1.2 miles) in diameter in the image. Each picture element (pixel) in this image is approximately 0.68 kilometers (0.41 miles) across. This image which was taken by the Galileo spacecraft's solid state imaging (CCD) system during its eighth orbit around Jupiter, on May 6th, 1997. The center of the image is located at 71.3 degrees south latitude, 97.6 degrees west longitude, and was taken when the spacecraft was approximately 35,470 kilometers (21,637 miles) from Callisto. 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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Io's Pele Hemisphere
PIA00718
Jupiter
Solid-State Imaging
| Title |
Io's Pele Hemisphere |
| Original Caption Released with Image |
Jupiter's moon Io with Pele prominently in view. The inset images are from the Voyager 1 (top) and 2 (bottom) spacecraft using the violet, blue, and orange filters. The large image is from Galileo, using the violet, green, and red filters. The colors in the Galileo image are closer to what the human eye would see. With the filters used in the Solid State Imaging system on Galileo, it is clear now that some of the recent volcanic deposits on Io are indeed very red, a point not resolved by Voyager. Scientists speculate that the red deposits are a form of Sulfur produced in volcanic eruptions on Io. Note the rapid changes seen in the shape of the distal (far from the vent) plume deposits from Pele between Voyagers 1 (April, 1979) and 2 (July, 1979). The Galileo image was obtained by the imaging system on board the spacecraft in June, 1996. North is to the top. The Jet Propulsion Laboratory, Pasadena, CA manages the mission for NASA'is 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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Mass wasting in craters near
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PIA01222
Jupiter
Solid-State Imaging
| Title |
Mass wasting in craters near the south pole of Callisto |
| Original Caption Released with Image |
Craters ranging in diameter from the limit of resolution, approximately 1.35 kilometers (0.82 miles), up to the remnants of a heavily degraded two-ringed basin (center of the image), approximately 90 kilometers (55 miles) in diameter, can be seen in this image of a region near Callisto's south pole. Craters in this image exhibit a wide variety of degradational (erosional) states, including what appear to be landslide or slump deposits, best seen in the southwestern part of the bright 21 kilometer crater Randver, just east of the center of the image. The relative youth of Randver is evidenced by its bright and easily identifiable ejecta blanket (the materials ejected during the formation of the crater). The northeast facing slopes in this region are typically the brightest portion of the crater rims. Craters in the south and southwestern portions of this image are the most highly modified and degraded, and are therefore considered to be the oldest craters in the area. North is to the top of the image which was taken by the Galileo spacecraft's solid state imaging (CCD) system during its eighth orbit around Jupiter on May 6, 1997. The center of the image is located 73.2 degrees south latitude, 54.4 degrees west longitude, and was taken when the spacecraft was approximately 35,464 kilometers (21,633 miles) from Callisto. 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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