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Iapetus: A View from the Top
| Description |
Iapetus: A View from the Top |
| Full Description |
This oblique view of Saturn's moon Iapetus from high latitude shows how the dark, heavily cratered terrain of Cassini Regio transitions to a bright, icy terrain at high latitudes. In this mosaic of two high resolution images taken during Cassini's New Year's Eve 2004 flyby of Iapetus, the direction toward the north pole is approximately 15 degrees below the horizontal on the right. At the equator terrains are uniformly covered with a dark mantle of material that has a reflectivity of about 4 percent. At latitudes toward the pole of about 40 degrees, the dark deposits become patchy and diffuse as the surface transitions to a much brighter, icy terrain near the pole. The brightest icy materials exhibit visual reflectivity over 60 percent. Superimposed on the bright terrain is a subtle, ghostly pattern of crudely parallel, north-south trending wispy streaks. The streaks, which were discovered during this flyby of Iapetus, are typically a few kilometers wide and sometimes tens of kilometers long. Their appearance and orientation may be connected with the emplacement of dark materials that cover Cassini Regio. The dark materials might represent the gradual accumulation of dark debris falling from space, or alternatively, may represent fallout from plume-style eruptions that may have accompanied the formation of Iapetus's enigmatic equatorial ridge (see PIA 06166). Also seen in this mosaic are conspicuous, north-facing bright crater walls. An example can be seen in the upper left where the bright, 4-kilometer-high (2.5 miles) walls of a 70 kilometer (44 mile) central-peak crater lies. The bright crater walls are often higher in brightness than the corresponding south-facing walls of the same crater. They are vaguely reminiscent of bright north-facing crater walls that were discovered by NASA's Voyager and Galileo spacecraft in craters near the poles of the Jovian satellites Callisto and Ganymede. In the case of the Jovian satellites, cold-trapping of frosts on north-facing slopes and sublimation of ices from south-facing slopes are thought to produce the north-south asymmetries in crater wall brightness. However, the occurrence of some young-appearing craters on Iapetus that have bright north-facing and dark south-facing slopes, and the pattern of streaks near the north pole of Iapetus suggests that another mechanism may be responsible for the crater wall brightness asymmetries on Iapetus. One possibility is that the south-facing slopes may be stained by the same process that emplaced the low brightness coating throughout the region. In this case, the north-pointing scarps might be bright because they face away and are shielded from the putative falling spray of dark materials. Bright south-facing slopes would exist primarily on young craters that have not been exposed to the darkening agent long enough to be stained. The image was obtained in visible light with the Cassini spacecraft narrow angle camera on Dec. 31, 2004, at a distance of, about 123,370 kilometers (76,658 miles) from Iapetus and at a Sun-Iapetus-spacecraft, or phase, angle of 93 degrees. Resolution achieved in the original image was 732 meters (2,401 feet) per pixel. The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the mission for NASA's Science Mission Directorate, Washington, D.C. The Cassini orbiter and its two onboard cameras were designed, developed and assembled at JPL. The imaging team is based at the Space Science Institute, Boulder, Colo. For more information about the Cassini-Huygens mission visit http://saturn.jpl.nasa.gov . For images visit the Cassini imaging team home page http://ciclops.org . Credit: NASA/JPL/Space Science Institute |
| Date |
January 7, 2005 |
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Giant Landslide on Iapetus
| Description |
Giant Landslide on Iapetus |
| Full Description |
A spectacular landslide within the low-brightness region of Iapetus's surface known as Cassini Regio is visible in this image from Cassini. Iapetus is one of the moons of Saturn. The landslide material appears to have collapsed from a scarp 15 kilometers high (9 miles) that forms the rim of an ancient 600 kilometer (375 mile) impact basin. Unconsolidated rubble from the landslide extends halfway across a conspicuous, 120-kilometer diameter (75-mile) flat-floored impact crater that lies just inside the basin scarp. Landslides are common geological phenomena on many planetary bodies, including Earth and Mars. The appearance of this landslide on an icy satellite with low-brightness cratered terrain is reminiscent of landslide features that were observed during NASA's Galileo mission on the Jovian satellite Callisto. The fact that the Iapetus landslide traveled many kilometers from the basin scarp could indicate that the surface material is very fine-grained, and perhaps was fluffed by mechanical forces that allowed the landslide debris to flow extended distances. In this view, north is to the left of the picture and solar illumination is from the bottom of the frame. The image was obtained in visible light with the Cassini spacecraft narrow angle camera on Dec. 31, 2004, at a distance of about 123,400 kilometers (76,677 miles) from Iapetus and at a Sun-Iapetus-spacecraft, or phase, angle of 78 degrees. Resolution achieved in the original image was 740 meters (2,428 feet) per pixel. The image has been contrast-enhanced and magnified by a factor of two to aid visibility. The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the mission for NASA's Science Mission Directorate, Washington, D.C. The Cassini orbiter and its two onboard cameras were designed, developed and assembled at JPL. The imaging team is based at the Space Science Institute, Boulder, Colo. For more information about the Cassini-Huygens mission visit http://saturn.jpl.nasa.gov . For images visit the Cassini imaging team home page http://ciclops.org . Credit: NASA/JPL/Space Science Institute |
| Date |
January 7, 2005 |
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| Description |
Here on the Gallery page you can find the very latest images, videos and products from the Cassini-Huygens mission to Saturn, including the spectacular launch, spacecraft assembly and the exciting trip to Saturn. |
| Full Description |
One moment in an ancient, orbital dance is caught in this color picture taken by NASA's Cassini spacecraft on Dec. 7, 2000, just as two of Jupiter's four major moons, Europa and Callisto, were nearly perfectly aligned with each other and the center of the planet. The distances are deceiving. Europa, seen against Jupiter, is 600,000 kilometers (370,000 miles) above the planet's cloud tops. Callisto, at lower left, is nearly three times that distance from the cloud tops. Europa is a bit smaller than Earth's Moon and has one of the brightest surfaces in the solar system. Callisto is 50 percent bigger -- roughly the size of Saturn's largest satellite, Titan -- and three times darker than Europa. Its brightness had to be enhanced in this picture, relative Europa's and Jupiter's, in order for Callisto to be seen in this image. Europa and Callisto have had very different geologic histories but share some surprising similarities, such as surfaces rich in ice. Callisto has apparently not undergone major internal compositional stratification, but Europa's interior has differentiated into a rocky core and an outer layer of nearly pure ice. Callisto's ancient surface is completely covered by large impact craters: The brightest features seen on Callisto in this image were discovered by the Voyager spacecraft in 1979 to be bright craters, like those on our Moon. In contrast, Europa's young surface is covered by a wild tapestry of ridges, chaotic terrain and only a handful of large craters. Recent data from the magnetometer carried by the Galileo spacecraft, which has been in orbit around Jupiter since 1995, indicate the presence of conducting fluid, most likely salty water, inside both Callisto and Europa. Scientists are eager to discover whether the surface of Saturn's Titan resembles that of Callisto or Europa, or whether it is entirely different, when Cassini finally reaches its destination in 2004. Cassini is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the Cassini mission for NASA's Office of Space Science, Washington, D.C. Credit: NASA/JPL/University of Arizona For higher resolution, click here. |
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Map of Titan in Infrared
| Description |
Mosaic of Titan obtained at the 2.03 micron wavelength |
| Full Description |
On Oct. 26, 2004, the Cassini spacecraft flew over Saturn's moon Titan at less than 1,200 kilometers (746 miles) at closest approach. Cassini acquired several infrared images with spatial resolution ranging from a few tens of kilometers (several miles) to 2 kilometers (1.2 miles) per pixel. The visual and infrared mapping spectrometer instrument took images from visible wavelengths to the 5.1 micron wavelength. This figure shows the mosaic obtained at the 2.03 micron wavelength. Observations are centered on the hemisphere of Titan that points away from Saturn. The left (inset) high-resolution image is 30 kilometers (19 miles) per pixel. It shows the site where the European Space Agency's Huygens probe successfully landed on Jan. 14, 2005. The right inset shows a circular feature that scientists think is a volcano, which may be responsible for replenishing Titan's methane atmosphere. Titan¿s diameter is 5,151 kilometers (3,200 miles), which is larger than Jupiter's moon Callisto and smaller than another Jovian moon, Ganymede. Callisto has a diameter of 4,806 kilometers (2,986 miles) and Ganymede is 5,268 kilometers (3,273 miles). The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the mission for NASA's Science Mission Directorate, Washington, D.C. The Cassini orbiter and its two onboard cameras were designed, developed and assembled at JPL. The visual and infrared mapping spectrometer team is based at the University of Arizona. For more information about the Cassini-Huygens mission visit http://saturn.jpl.nasa.gov . The visual and infrared mapping spectrometer team homepage is at http://wwwvims.lpl.arizona.edu . Credit: NASA/JPL/University of Arizona |
| Date |
June 8, 2005 |
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Moons of the Solar System
| title |
Moons of the Solar System |
| description |
All the planetary moons in our solar system are shown here at their correct relative size and true color. Their diversity of size and appearance is testament to the unique and fascinating geologic history that each of these bodies has undergone. Two of the moons are larger than the planet Mercury, and eight of them are larger than Pluto. Earth's Moon is the fifth largest of the set, with a diameter of 3476 kilometers (2160 miles). Most of the moons are thought to have formed from a disk of debris left over from formation of the planet they orbit. However Triton, Neptune's largest moon, and several of the smallest moons, including the moons of Mars, are thought to be captured planetesimals that formed elsewhere in the solar system. Earth's Moon is thought to have formed from the debris ejected from a roughly Mars-sized object colliding with the early Earth, perhaps a unique event in the history of the solar system. The moons are organized on the diagram by the planet they orbit (top to bottom with increasing distance from the Sun) and their position relative to the planet (left to right with increasing distance from the planet). Below is a listing of the names of all the moons and the planets they orbit. Most moons are named for mythological characters associated with the character the planet is named for. While most of the planets are named for Roman characters (with the exceptions of Pluto and Uranus), most of the moon have names from Greek mythology. For example, Phobos and Deimos are the sons of Ares, the Greek version of Mars. Jupiter?s moons are all named for lovers and other close associates of Zeus (Jupiter). Saturn?s moons are named for Titans, the race that included Cronos (Saturn), Zeus? father. Neptune?s moons are named for mythological characters associated with water, and Charon was the ferryman of the dead who brought people to Pluto?s realm. By tradition, the discoverer of a moon gets to name it (now subject to approval by the International Astronomical Union). The son of the discoverer of the first two moons of Uranus (Sir William Herschel) decided to name Uranus? moons not for mythological characters, but instead for the king and queen of fairies in Shakespear?s A Midsummer Night?s Dream . This began a tradition whereby all uranian satellites are named for fairy characters in English drama. To read more about the names of the planets and their satellites, go to the U.S. Geological Survey?s nomenclature guide at http://wwwflag.wr.usgs.gov/USGSFlag/Space/nomen/append7.html . *Earth* Moon *Mars * Phobos, Deimos *Jupiter* Metis, Adrastea, Amalthea, Thebe, Io, Europa, Ganymede, Callisto, Leda, Himalia, Lysithea, Elara, Ananke, Carme, Pasiphae, Sinope *Saturn * Pan, Atlas, Prometheus, Pandora, Epimetheus, Janus, Mimas, Enceladus, Tethys, Calypso, Telesto, Dione, Helene, Rhea, Titan, Hyperion, Iapetus, Phoebe *Uranus * Cordelia, Ophelia, Bianca, Cressida, Desdemona, Juliet, Portia, Rosalind, Belinda, Puck, Miranda,, Ariel, Umbriel, Titania, Oberon *Neptune* Naiad, Thalassa, Despina, Galatea, Larissa, Proteus, Triton, Nereid *Pluto * Charon *Image Credit*: Image processing by Tim Parker (Jet Propulsion Laboratory) and Paul Schenk and Robert Herrick (Lunar and Planetary Institute), based on NASA images. |
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Jupiter Flyby
| title |
Jupiter Flyby |
| description |
Although the main mission of the New Horizons spacecraft is to explore the Pluto system and the Kuiper Belt of icy objects, it will first fly by the solar system's largest planet, Jupiter, in 2007 - a little over a year after the planned launch date. In this artist's rendering, New Horizons is just past its closest approach to the planet. Near the Sun are Earth, Venus and Mercury. The dim crescent shape at the upper right of the Sun is Callisto, the outermost of Jupiter's four largest moons. Just left of Jupiter is Europa. *Image Credit*: Southwest Research Institute (Dan Durda)/Johns Hopkins University Applied Physics Laboratory (Ken Moscati) |
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Asgard
| title |
Asgard |
| date |
11.04.1996 |
| description |
This four-frame mosaic shows the ancient impact structure Asgard on Jupiter's moon Callisto. This image is centered at 300N, 1420W. The Asgard structure is approximately 1700 kilometers across 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 images. This image was taken on November 4, 1996, at a distance of 111,891 kilometers by the Solid-State Imaging System onboard the Galileo spacecraft during its third orbit around Jupiter. *Image Credit*: Deutsche Forschungsanstalt fuer Luft-und Raumfahrt (DLR) |
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Callisto's Har Crater
| title |
Callisto's Har Crater |
| date |
11.04.1997 |
| description |
This image shows a heavily cratered region near Callisto's equator. It was taken by the Galileo spacecraft's Solid-State Imaging System on its ninth orbit around Jupiter. North is to the top of the image. The 105-kilometer 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 41-kilometer 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 3.30S latitude and 357.90W longitude, covers an area of 245 kilometers by 230 kilometers. The Sun illuminates the scene from the west (left). The smallest distinguishable features in the image are about 294 meters across. This image was obtained on June 25, 1997, when Galileo was 14,080 kilometers from Callisto. *Image Credit*: Arizona State University |
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Callisto Landslides
| title |
Callisto Landslides |
| date |
12.10.1997 |
| description |
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 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 that 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 that allowed the landslide debris to flow extended distances in the absence of an atmosphere. This image was acquired on September 16, 1997, by the Solid-State Imaging System onboard the Galileo spacecraft during it'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 25.30N latitude, 141.30W longitude. The image, which is 55 kilometers by 44 kilometers across, was acquired at a resolution of 100 meters per picture element. *Image Credit*: Arizona State University |
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Family Portrait of Jupiter's
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| title |
Family Portrait of Jupiter's Great Red Spot and the Galilean Satellites |
| description |
This "family portrait," a composite of the Jovian system, includes the edge of Jupiter with its Great Red Spot, and Jupiter's four largest moons, known as the Galilean satellites. From top to bottom, the moons shown are Io, Europa, Ganymede and Callisto. The Great Red Spot, a storm in Jupiter's atmosphere, is at least 300 years old. Winds blow counterclockwise around the Great Red Spot at about 400 kilometers per hour (250 miles per hour). The storm is larger than one Earth diameter from north to south, and more than two Earth diameters from east to west. In this oblique view, the Great Red Spot appears longer in the north-south direction. Europa, the smallest of the four moons, is about the size of Earth's moon, while Ganymede is the largest moon in the solar system. North is at the top of this composite picture in which the massive planet and its largest satellites have all been scaled to a common factor of 15 kilometers (9 miles) per picture element. The Solid State Imaging (CCD) system aboard NASA's Galileo spacecraft obtained the Jupiter, Io and Ganymede images in June 1996, while the Europa images were obtained in September 1996. Because Galileo focuses on high resolution imaging of regional areas on Callisto rather than global coverage, the portrait of Callisto is from the 1979 flyby of NASA's Voyager spacecraft. Launched in October 1989, the spacecraft's mission was to conduct detailed studies of the giant planet, its largest moons and the Jovian magnetic environment. The Jet Propulsion Laboratory, Pasadena, CA, managed the mission for NASA's Office of Space Science, Washington, DC. *Image Credit*: NASA |
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Callisto Impact Craters
| title |
Callisto Impact Craters |
| date |
12.07.1998 |
| description |
This composite of Galileo spacecraft images 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 multiring structure located near 300N latitude, 1420W longitude. The Asgard structure is approximately 1700 kilometers 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 Asgard is about 75 kilometers 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 in diameter, while the dome is about 25 kilometers 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 by the Solid-State Imaging 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 per picture element on September 16, 1997, during Galileo's tenth orbit when the spacecraft was less than 9500 kilometers from Callisto. *Image Credit*: Arizona State University |
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Jupiter and the Galilean Sat
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| title |
Jupiter and the Galilean Satellites |
| description |
Jupiter and its four planet-size moons, called the Galilean satellites, were photographed in early March by Voyager 1 and assembled into this collage. They are not to scale but are in their relative positions. Startling new discoveries on the Galilean moons and the planet Jupiter made by Voyager 1 have been factored into a new mission design for Voyager 2. Voyager 2 will fly past Jupiter on July 9. Reddish Io (upper left) is nearest Jupiter, then Europa (center), Ganymede and Callisto (lower right). Nine other much smaller satellites circle Jupiter, one inside Io's orbit and the other millions of miles from the planet. Not visible is Jupiter's faint ring of particles, seen for the first time by Voyager 1. The Voyager Project is managed for NASA's Office of Space Science by Jet Propulsion Laboratory, California Institute of Technology. *Image Credit*: NASA |
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Jupiter's Moon Callisto
| title |
Jupiter's Moon Callisto |
| date |
03.06.1979 |
| description |
Voyager 1 image of Jupiter's moon Callisto from a distance of 350,000 km. Callisto is about 4,800 km in diameter (about the size of Mercury). Features as small as 7 km across can be seen in this image. The large "bulls-eye" at the top of the image is believed to be an impact basin formed early in Callisto's history. The bright center of the basin is about 600 km across and the outer ring is about 2600 km across. (Voyager 1, P-21287) *Image Credit*: NASA |
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Triple Eclipse
| title |
Triple Eclipse |
| description |
At first glance, Jupiter looks like it has a mild case of the measles. Five spots - one colored white, one blue, and three black are scattered across the upper half of the planet. Closer inspection by NASA's Hubble Space Telescope reveals that these spots are actually a rare alignment of three of Jupiter's largest moons - Io, Ganymede, and Callisto - across the planet's face. In this image, the telltale signatures of this alignment are the shadows [the three black circles] cast by the moons. Io's shadow is located just above center and to the left, Ganymede's on the planet's left edge, and Callisto's near the right edge. Only two of the moons, however, are visible in this image. Io is the white circle in the center of the image, and Ganymede is the blue circle at upper right. Callisto is out of the image and to the right. On Earth, we witness a solar eclipse when our Moon's shadow sweeps across our planet's face as it passes in front of our Sun. Jupiter, however, has four moons roughly the same size as Earth's Moon. The shadows of three of them occasionally sweep simultaneously across Jupiter. The image was taken March 28, 2004, with Hubble's Near Infrared Camera and Multi-Object Spectrometer. Seeing three shadows on Jupiter happens only about once or twice a decade. Why is this triple eclipse so unique? Io, Ganymede, and Callisto orbit Jupiter at different rates. Their shadows likewise cross Jupiter's face at different rates. For example, the outermost moon Callisto orbits the slowest of the three satellites. Callisto's shadow moves across the planet once for every 20 shadow crossings of Io. Add the crossing rate of Ganymede's shadow and the possibility of a triple eclipse becomes even more rare. Viewing the triple shadows in 2004 was even more special, because two of the moons were crossing Jupiter's face at the same time as the three shadows. Jupiter appears in pastel colors in this photo because the observation was taken in near-infrared light. Astronomers combined images taken in three near-infrared wavelengths to make this color image. The photo shows sunlight reflected from Jupiter's clouds. In the near infrared, methane gas in Jupiter's atmosphere limits the penetration of sunlight, which causes clouds to appear in different colors depending on their altitude. Studying clouds in near-infrared light is very useful for scientists studying the layers of clouds that make up Jupiter's atmosphere. Yellow colors indicate high clouds, red colors lower clouds, and blue colors even lower clouds in Jupiter's atmosphere. The green color near the poles comes from a thin haze very high in the atmosphere. Ganymede's blue color comes from the absorption of water ice on its surface at longer wavelengths. Io's white color is from light reflected off bright sulfur compounds on the satellite's surface. In viewing this rare alignment, astronomers also tested a new imaging technique. To increase the sharpness of the near-infrared camera images, astronomers, speeded up Hubble's tracking system so that Jupiter traveled through the telescope's field of view much faster than normal. This technique allowed scientists to take rapid-fire snapshots of the planet and its moons. They then combined the images into one single picture to show more details of the planet and its moons. *Image Credit*: NASA, ESA, and E. Karkoschka (University of Arizona) |
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Capturing Callisto
| title |
Capturing Callisto |
| date |
02.27.2007 |
| description |
The New Horizons Long Range Reconnaissance Imager (LORRI) captured these two images of Jupiter's outermost large moon, Callisto, as the spacecraft flew past Jupiter in late February. New Horizons' closest approach distance to Jupiter was 2.3 million kilometers (1.4 million miles), not far outside Callisto's orbit, which has a radius of 1.9 million kilometers (1.2 million miles). However, Callisto happened to be on the opposite side of Jupiter during the spacecraft's pass through the Jupiter system, so these images, taken from 4.7 million kilometers (3.0 million miles) and 4.2 million kilometers (2.6 million miles) away, are the closest of Callisto that New Horizons obtained. Callisto's ancient, crater-scarred surface makes it very different from its three more active sibling satellites, Io, Europa and Ganymede. Callisto, 4,800 kilometers (3000 miles) in diameter, displays no large-scale geological features other than impact craters, and every bright spot in these images is a crater. The largest impact feature on Callisto, the huge basin Valhalla, is visible as a bright patch at the 10 o'clock position. The craters are bright because they have excavated material relatively rich in water ice from beneath the dark, dusty material that coats most of the surface. The two images show essentially the same side of Callisto - the side that faces Jupiter - under different illumination conditions. The images accompanied scans of Callisto's infrared spectrum with New Horizons' Linear Etalon Imaging Spectral Array (LEISA). The New Horizons science team designed these scans to study how the infrared spectrum of Callisto's water ice changes as lighting and viewing conditions change, and as the ice cools through Callisto's late afternoon. The infrared spectrum of water ice depends slightly on its temperature, and a goal of New Horizons when it reaches the Pluto system (in 2015) is to use the water ice features in the spectrum of Pluto's moon Charon, and perhaps on Pluto itself, to measure surface temperature. Callisto provided an ideal opportunity to test this technique on a much better-known body. The left image, taken at 05:03 Universal Time on February 27, 2007, is centered at 5 degrees south, 5 degrees west, and has a solar phase angle of 46 degrees. The right image was taken at 03:25 Universal Time on February 28, 2007. It is centered at 4 degrees south, 356 degrees west, and has a solar phase angle of 76 degrees. Released: April 5, 2007 Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute |
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Jupiter System Montage
| Title |
Jupiter System Montage |
| Full Description |
Jupiter and its four planet-size moons, called the Galilean satellites, were photographed in early March 1979 by Voyager 1 and assembled into this collage. They are not to scale but are in their relative positions. Startling new discoveries on the Galilean moons and the planet Jupiter made by Voyager l factored into a new mission design for Voyager 2. Reddish Io (upper left) is nearest Jupiter, then Europa (center), Ganymede and Callisto (lower right). Nine other much smaller satellites circle Jupiter, one inside Io's orbit and the other millions of miles from the planet. Not visible is Jupiter's faint ring of particles, seen for the first time by Voyager 1. The Voyager Project is managed for NASA's Office of Space Science by Jet Propulsion Laboratory, California Institute of Technology. |
| Date |
06/22/1979 |
| NASA Center |
Jet Propulsion Laboratory |
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Voyager 1 View of Callisto
| Title |
Voyager 1 View of Callisto |
| Full Description |
Voyager 1 took this picture of Callisto during Voyager's approach to Jupiter's outer large satellite in 1979. Both Galileo and Marius discovered Callisto in 1610. In Greek mythology, Callisto was a nymph loved by Zeus and thus hated by Hera. Hera turned her into a bear, which Zeus placed in the heavens as the constellation Ursa Major. Voyager was 350,000 kilometers from Callisto and took this picture that shows features about seven kilometers wide across the surface. Callisto is a little smaller than Ganymede (Callisto is about the size of Mercury) and it seems that it is composed of a mixture of ice and rock (about 40 percent ice and 60 percent rock and iron). The darker color of Callisto (about half as reflective as Ganymede but still twice as bright as the Moon) implies that the upper surface is "dirty ice" or water- rich rock frozen on Callisto's cold surface (approximately -243 Fahrenheit degrees at the equator). Callisto's atmosphere is mostly carbon dioxide. Far more craters appear on the surface of Callisto than on the surface of Ganymede, leading scientists to believe that Callisto is the oldest of the Galilean satellites. Callisto could date back as far as four billion years ago and has remained relatively unchanged in the history of space. |
| Date |
03/06/1979 |
| NASA Center |
Jet Propulsion Laboratory |
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Asgard Scarp Mosaic
| Title |
Asgard Scarp Mosaic |
| Description |
Low-resolution color data were combined with a higher resolution mosaic to produce this infrared composite image of a pair of ancient multi-ringed impact basins on Jupiter's moon, Callisto. The region imaged is on the leading hemisphere of Callisto near 26 degrees north, 142 degrees west, and is almost 1,400 kilometers (860 miles) across. North is toward the top of the picture and the Sun illuminates the surface from the east. Dominating the scene is the impact structure, Asgard, centered on the smooth, bright region near the middle of the picture and surrounded by concentric rings up to 1,700 kilometers (about 1,050 miles) in diameter. A second ringed structure with a diameter of about 500 kilometers (310 miles) can be seen to the north of Asgard, partially obscured by the more recent, bright-rayed crater, Burr. The icy materials excavated by the younger craters contrast sharply with the darker and redder coatings on older surfaces of Callisto. Launched in October 1989, Galileo entered orbit around Jupiter on Dec. 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. |
| Date |
02.10.1997 |
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Oberon at Voyager Closest Ap
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| Title |
Oberon at Voyager Closest Approach |
| Description |
This Voyager 2 picture of Oberon is the best the spacecraft acquired of Uranus' outermost moon. The picture was taken shortly after 3:30 a.m. PST on Jan. 24, 1986, from a distance of 660,000 kilometers (410,000 miles). The color was reconstructed from images taken through the narrow-angle camera's violet, clear and green filters. The picture shows features as small as 12 km (7 mi) on the moon's surface. Clearly visible are several large impact craters in Oberon's icy surface surrounded by bright rays similar to those seen on Jupiter's moon Callisto. Quite prominent near the center of Oberon's disk is a large crater with a bright central peak and a floor partially covered with very dark material. This may be icy, carbon-rich material erupted onto the crater floor sometime after the crater formed. Another striking topographic feature is a large mountain, about 6 km (4 mi) high, peeking out on the lower left limb. The Voyager project is managed for NASA by the Jet Propulsion Laboratory. |
| Date |
01.25.1986 |
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Callisto Close-up with Jagge
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| Title |
Callisto Close-up with Jagged Hills |
| Description |
The highest-resolution views ever obtained of any of Jupiter's moons, taken by NASA's Galileo spacecraft in May 2001, reveal numerous bright, sharp knobs covering a portion of Jupiter's moon Callisto. The knobby terrain seen throughout the top inset is unlike any seen before on Jupiter's moons. The spires are very icy but also contain some darker dust. As the ice erodes, the dark material apparently slides down and collects in low-lying areas. Over time, as the surface continues to erode, the icy knobs will likely disappear, producing a scene similar to the bottom inset. The number of impact craters in the bottom image indicates that erosion has essentially ceased in the dark plains shown in that image, allowing impact craters to persist and accumulate. The knobs are about 80 to 100 meters (260 to 330 feet) tall, and they may consist of material thrown outward from a major impact billions of years ago. The areas captured in the images lie south of Callisto's large Asgard impact basin. The smallest features discernable in the images are about 3 meters (10 feet) across. 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 athttp://galileo.jpl.nasa.gov [ http://galileo.jpl.nasa.gov ]. |
| Date |
08.22.2001 |
|
Callisto Crater Chain at Hig
…
| Title |
Callisto Crater Chain at High Resolution Shown in Context |
| Description |
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. |
| Date |
02.28.1997 |
|
Callisto Hemispherical Globe
…
| Title |
Callisto Hemispherical Globes |
| Description |
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). |
| Date |
10.17.2002 |
|
Callisto's Southern Hemisphe
…
| Title |
Callisto's Southern Hemisphere |
| Description |
These views of Callisto's southern hemisphere were taken by the Near Infrared Mapping Spectrometer just after closest approach in orbit G8 on May 6, 1997. These false color images show surface compositional differences, red = more ice, blue = less ice. The upper left view contains Buri, a crater with a diameter of about 60 km. In the infrared spectrum, Buri and the rays that extend from the crater have high abundance of water ice compared to the surrounding region. The center view, a large (200 km or 120 mile diameter) unnamed impact crater with a distinct ring or circle around it reveals a complex mix of ice and non-ice materials. This is possibly due to impact excavation of the ice-rich subsurface which suggests that the darker material is just a thin surface covering caused by impact debris or a lag deposit from which the ice has evaporated away. The infrared data shows spectral signatures for both sulfur and carbon as two potential materials which could play a part in the complicated make-up of Callisto's surface. 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. |
| Date |
09.26.1997 |
|
Rhea - icy cratered surface
| Title |
Rhea - icy cratered surface |
| Description |
The icy, cratered surface of Saturn's moon Rhea is seen in this image taken by Voyager 1 on Nov. 12, 1980, at a range of 85,000 kilometers (52,800 miles) as the spacecraft passed over the satellite's north pole. The heavily cratered surface attests to the satellite's ancient age. The largest craters, 50 to 100 kilometers (30 to 60 miles) across and several kilometers deep, are freshly preserved in Rhea's icy crust. The craters and landscape resemble those on the Moon and Mercury, and are unlike the flattened crater forms that have collapsed in the soft icy crusts of the Jovian moons Callisto, Ganymede and Europa. Scientists believe that Rhea (which is just 1,600 kilometers or 995 miles in diameter, compared to the 5,500-kilometer or 3,400-mile diameter of Ganymede) froze and became rigid, behaving like a rocky surface, very early in its history. The Voyager project is managed for NASA by the Jet Propulsion Laboratory, Pasadena, Calif. |
| Date |
02.10.1981 |
|
Global Callisto in Color
| Title |
Global Callisto in Color |
| Description |
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 athttp://galileo.jpl.nasa.gov [ http://galileo.jpl.nasa.gov ]. |
| Date |
08.22.2001 |
|
The Galilean Satellites
| Title |
The Galilean Satellites |
| Description |
This composite includes the four largest moons of Jupiter which are known as the Galilean satellites. From left to right, the moons shown are Ganymede, Callisto, Io, and Europa. The Galilean satellites were first seen by the Italian astronomer Galileo Galilei in 1610. In order of increasing distance from Jupiter, Io is closest, followed by Europa, Ganymede, and Callisto. The order of these satellites from the planet Jupiter helps to explain some of the visible differences among the moons. Io is subject to the strongest tidal stresses from the massive planet. These stresses generate internal heating which is released at the surface and makes Io the most volcanically active body in our solar system. Europa appears to be strongly differentiated with a rock/iron core, an ice layer at its surface, and the potential for local or global zones of water between these layers. Tectonic resurfacing brightens terrain on the less active and partially differentiated moon Ganymede. Callisto, furthest from Jupiter, appears heavily cratered at low resolutions and shows no evidence of internal activity. North is to the top of this composite picture in which these satellites have all been scaled to a common factor of 10 kilometers (6 miles) per picture element. The Solid State Imaging (CCD) system aboard NASA's Galileo spacecraft obtained the Io and Ganymede images in June 1996, while the Europa images were obtained in September 1996. Because Galileo focuses on high resolution imaging of regional areas on Callisto rather than global coverage, the portrait of Callisto is from the 1979 flyby of NASA's Voyager spacecraft. Launched in October 1989, the spacecraft's mission is to conduct detailed studies of the giant planet, its largest moons and the Jovian magnetic environment. The Jet Propulsion Laboratory, Pasadena, CA, manages the mission for NASA's Office of Space Science, Washington, DC. This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo mission home page at: http://galileo.jpl.nasa.gov. Background information and educational context for the images can be found at: http:/ /www.jpl.nasa.gov/galileo/sepo. |
| Date |
05.30.1997 |
|
Har Crater on Callisto
| Title |
Har Crater on Callisto |
| Description |
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. |
| Date |
11.04.1997 |
|
View of Callisto from Voyage
…
| Title |
View of Callisto from Voyager and Galileo |
| Description |
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 |
| Date |
12.03.1996 |
|
Jupiter's Inner Satellites a
…
| Title |
Jupiter's Inner Satellites and Ring Components |
| Description |
This schematic cut-away view of the components of Jupiter's ring system shows the geometry of the rings in relation to Jupiter and to the small inner satellites, which are the source of the dust which forms the rings. [figure removed for brevity, see original site] *The Formation of Jupiter's Ring System* The innermost and thickest ring, shown in gray shading, is the halo that ends at the main ring. The thin, narrow main ring, shown with red shading, is bounded by the 16- kilometer-wide (10-miles) satellite Adrastea and shows a marked decrease in brightness near the orbit of Jupiter's innermost moon, Metis. It is composed of fine particles knocked off Adrastea and Metis. Although the orbits of Adrastea and Metis are about 1,000 kilometers (about 600 miles) apart, that separation is not depicted in this drawing. Impacts by small meteoroids (fragments of asteroids and comets) into these small, low-gravity satellites feed material into the rings. Thebe and Amalthea, the next two satellites in increasing distance from Jupiter, supply dust which forms the thicker, disk-like "gossamer" rings. The gossamer rings, depicted with yellow and green shading, are thicker because the source satellites orbit Jupiter on inclined paths [figure removed for brevity, see original site] *Satellite Interactions with Jupiter's Ring System* These small satellites all orbit closer to Jupiter than the four largest Galilean satellites, Io, Europa, Ganymede and Callisto, which were discovered nearly 400 years ago. The orbital distances of the moons are drawn relative to the size of Jupiter.*Jupiter's Main Ring and Inner Satellites*Side view of system:Overhead view of system: [figure removed for brevity, see original site] [figure removed for brevity, see original site] The Jupiter image was created from a map based on data obtained by the Hubble Space Telescope. JPL manages the Galileo mission for NASA's Office of Space Science, Washington, DC. The images are posted on the Internet athttp://photojournal.jpl.nasa.gov/ [ http://photojournal.jpl.nasa.gov/ ]and athttp://galileo.jpl.nasa.gov [ http://galileo.jpl.nasa.gov ]. Background information and educational context for the images can be found at:http://www.jpl.nasa.gov/galileo/sepo [ http://www.jpl.nasa.gov/galileo/sepo ]. |
| Date |
09.15.1998 |
|
Large impact on Callisto`s s
…
| Title |
Large impact on Callisto`s southern hemisphere |
| Description |
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 |
| Date |
07.25.1997 |
|
Callisto From 8,023,000 kilo
…
PIA01510
Jupiter
Imaging Science Subsystem -
…
| Title |
Callisto From 8,023,000 kilometers |
| Original Caption Released with Image |
This photo of Callisto, outermost of Jupiter's four Galilean satellites, was taken a few minutes after midnight (PST) Feb. 26 by Voyager 1. The distance to Callisto was 8,023,000 kilometers (4.98 million miles). The hemisphere in this picture shows a fairly uniform surface dotted with brighter spots that are up to several hundred kilometers across. Scientists believe the spots may be impact craters but higher-resolution photos will be necessary before the features can be interpreted. Callisto is about the same size as the planet Mercury -- about 5,000 kilometers (3,000 miles) in diameter. Callisto is much less massive than Mercury, however, giving density less than twice that of water. Scientists believe Callisto, therefore, is composed of a mixture of rock and ice (up to about 50 percent by weight). Its surface is darker than those of the other Galilean satellites, but is still about twice as bright as Earth's Moon. This color photo was assembled from three black and white images in the Image Processing Lab at Jet Propulsion Laboratory. JPL manages and controls the Voyager project for NASA's Office of Space Science. |
|
Textured Terrain in Callisto
…
PIA01629
Jupiter
| Title |
Textured Terrain in Callisto's Asgard Basin |
| Original Caption Released with Image |
This fascinating region of Jupiter's icy moon, Callisto, shows the transition from the inner part of an enormous impact basin, Asgard, to the outer "surrounding plains." Small, bright, fine textured, closely spaced bumps appear throughout the inner part of the basin (top of image) and create a more fine textured appearance than that seen on many of the other inter-crater plains on Callisto. At low resolution, these icy bumps make Asgard's center brighter than the surrounding terrain. What caused the bumps to form is still unknown, but they are associated clearly with the impact that formed Asgard. The ridge that cuts diagonally across the lower left corner is one of many giant concentric rings that extend for hundreds of kilometers outside Asgard's center. Exterior to the ring (lower left corner), Callisto's surface changes significantly. Still peppered with craters, the number of icy bumps decreases while their average size increases. The fine texture is not as visible in the middle of the image. One explanation is that material from raised features (such as the ridge) may slide down slope and cover small scale features. Such images of Callisto help us understand the dynamics of giant impacts into icy surfaces, and how the large structures change with time. North is to the top of the picture. The image, centered at 27.1 degrees north latitude and 142.3 degrees west longitude, covers an area approximately 80 kilometers (50 miles) by 90 kilometers (55 miles). The resolution is about 90 meters (295 feet) per picture element. The image was taken on September 17th, 1997 at a range of 9200 kilometers (5700 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 ]. |
|
Asgard Multi-Ring Structure
…
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 ]. |
|
Asgard impact structure on C
…
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 |
|
Crater Tindr on Callisto - a
…
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 ]. |
|
A Chain of Impact Craters on
…
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/ ]. |
|
Callisto's Valhalla impact s
…
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/ ]. |
|
Europa, Ganymede, and Callis
…
PIA01656
Jupiter
Solid-State Imaging
| Title |
Europa, Ganymede, and Callisto: Surface comparison at high spatial resolution |
| Original Caption Released with Image |
Ganymede's youngest large craters would have been created only about one billion years ago. Europa's surface in this model should be very young, with this satellite being geologically quite active even today. The images were taken by the Solid State Imaging (SSI) system on NASA's Galileo spacecraft. They were processed by the Institute of Planetary Exploration of the German Aerospace Center (DLR) in Berlin, Germany, and scaled to a size of 150 meters per pixel (m/pixel). North is up in all images. The spatial resolution of the original data was 180 m/pixel for Europa and Ganymede and 90 m/pixel for Callisto. The Europa image was taken during Galileo's 6th orbit, the Ganymede image during the 7th, and the Callisto image during the 10th orbit. The Jet Propulsion Laboratory, Pasadena, CA manages the Galileo mission for NASA's Office of Space Science, Washington, DC. This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo mission home page at URL http://galileo.jpl.nasa.gov [ http://galileo.jpl.nasa.gov ]. Background information and educational context for the images can be found at URL http://www.jpl.nasa.gov/galileo/sepo [ http://www.jpl.nasa.gov/galileo/sepo ]., These images show a comparison of the surfaces of the three icy Galilean satellites, Europa, Ganymede, and Callisto, scaled to a common resolution of 150 meters per picture element (pixel). Despite the similar distance of 0.8 billion kilometers to the sun, their surfaces show dramatic differences. Callisto (with a diameter of 4817 kilometers) is "peppered" by impact craters, but is also covered by a dark material layer of so far unknown origin, as seen here in the region of the Asgard multi-ring basin. It appears that this layer erodes or covers small craters. Ganymede's landscape is also widely formed by impacts, but different from Callisto, much tectonic deformation can be observed in the Galileo images, such as these of Nicholson Regio. Ganymede, with a diameter of 5268 kilometers (one-and-a-half times larger than the Earth's moon), is the largest moon in the solar system. Contrary to Ganymede and Callisto, Europa (diameter 3121 kilometers) has a sparsely cratered surface, indicating that geologic activity took place more recently. Globally, ridged plains and the so-called "mottled terrain" are the main landforms. In the high-resolution image presented here showing the area around the Agave and Asterius dark lineaments, older ridges dominate the surface, while a small part of the younger mottled terrain is visible to the lower left of the image center. While all three moons are believed to be nearly as old as the solar system (4.5 billion years), the age of the surfaces, i.e. the time since the last major geologic activity took place, is still subject to debate. Without having surface samples in hand, the only method to roughly determine a planet's or satellite's geologic surface age is by crater counting. However, assumptions about the impactor fluxes must be made based on theoretical models and possible observations of candidate impactors such as asteroids and comets. Asteroids should have been very common in the early days of the solar system, but this source should have been largely exhausted by about 3.8 billion years before present. For comets, the impactor flux is believed to be rather constant throughout the whole lifetime of the solar system, meaning that the probability of an impact of a large comet is similar today as it was, say, four billion years ago. Assuming the asteroids have been the dominant bodies that impacted the Galilean satellites (which is believed to be the case on the Moon, the Earth, and other inner solar system bodies as well as within the asteroid belt itself), the surfaces of Ganymede and Callisto must be old, roughly four billion years. In this case, the Europan surface would by comparison have a mean age of one-hundred to several-hundred million years. Low-level geologic activity on Europa might be possible, but Ganymede and Callisto should be geologically dead. Assuming on the other hand that comets have been the main impactors in the Jovian system, Callisto's surface would still be determined to be old, but |
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NIMS Callisto Global Mosaic
PIA00844
Jupiter
Near Infrared Mapping Spectr
…
| Title |
NIMS Callisto Global Mosaic |
| Original Caption Released with Image |
The Near Infrared Mapping Spectrometer (NIMS) acquired this global mosaic (right) at a spatial resolution of 100 km during Galileo's third orbit on November 4, 1996, roughly 7.5 hours prior to Callisto closest approach. The lighter bluish area in the upper latitudes is the Asgard multi-ring structure (the second largest surface feature on Callisto) with crater Burr to the north and Tornasuk to the east. The bluish color indicates regions with more exposed water ice while the reddish/rusty color indicates surface areas rich in non-ice minerals. Spectra: * Click on Asgard to view a sample spectrum of this region. This spectrum shows a higher abundance of ice between 1 and 2 microns. * Click on the dark terrain to view sample spectra of Callisto's surface which shows more "rocky" material and less ice. * Click here to compare the two spectra. The Jet Propulsion Laboratory, Pasadena, CA manages the mission for NASA's Office of Space Science, Washington, DC. 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. |
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NIMS Callisto Global Mosaic
PIA00844
Jupiter
Near Infrared Mapping Spectr
…
| Title |
NIMS Callisto Global Mosaic |
| Original Caption Released with Image |
The Near Infrared Mapping Spectrometer (NIMS) acquired this global mosaic (right) at a spatial resolution of 100 km during Galileo's third orbit on November 4, 1996, roughly 7.5 hours prior to Callisto closest approach. The lighter bluish area in the upper latitudes is the Asgard multi-ring structure (the second largest surface feature on Callisto) with crater Burr to the north and Tornasuk to the east. The bluish color indicates regions with more exposed water ice while the reddish/rusty color indicates surface areas rich in non-ice minerals. Spectra: * Click on Asgard to view a sample spectrum of this region. This spectrum shows a higher abundance of ice between 1 and 2 microns. * Click on the dark terrain to view sample spectra of Callisto's surface which shows more "rocky" material and less ice. * Click here to compare the two spectra. The Jet Propulsion Laboratory, Pasadena, CA manages the mission for NASA's Office of Space Science, Washington, DC. 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. |
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NIMS Callisto Global Mosaic
PIA00844
Jupiter
Near Infrared Mapping Spectr
…
| Title |
NIMS Callisto Global Mosaic |
| Original Caption Released with Image |
The Near Infrared Mapping Spectrometer (NIMS) acquired this global mosaic (right) at a spatial resolution of 100 km during Galileo's third orbit on November 4, 1996, roughly 7.5 hours prior to Callisto closest approach. The lighter bluish area in the upper latitudes is the Asgard multi-ring structure (the second largest surface feature on Callisto) with crater Burr to the north and Tornasuk to the east. The bluish color indicates regions with more exposed water ice while the reddish/rusty color indicates surface areas rich in non-ice minerals. Spectra: * Click on Asgard to view a sample spectrum of this region. This spectrum shows a higher abundance of ice between 1 and 2 microns. * Click on the dark terrain to view sample spectra of Callisto's surface which shows more "rocky" material and less ice. * Click here to compare the two spectra. The Jet Propulsion Laboratory, Pasadena, CA manages the mission for NASA's Office of Space Science, Washington, DC. 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. |
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NIMS Callisto Global Mosaic
PIA00844
Jupiter
Near Infrared Mapping Spectr
…
| Title |
NIMS Callisto Global Mosaic |
| Original Caption Released with Image |
The Near Infrared Mapping Spectrometer (NIMS) acquired this global mosaic (right) at a spatial resolution of 100 km during Galileo's third orbit on November 4, 1996, roughly 7.5 hours prior to Callisto closest approach. The lighter bluish area in the upper latitudes is the Asgard multi-ring structure (the second largest surface feature on Callisto) with crater Burr to the north and Tornasuk to the east. The bluish color indicates regions with more exposed water ice while the reddish/rusty color indicates surface areas rich in non-ice minerals. Spectra: * Click on Asgard to view a sample spectrum of this region. This spectrum shows a higher abundance of ice between 1 and 2 microns. * Click on the dark terrain to view sample spectra of Callisto's surface which shows more "rocky" material and less ice. * Click here to compare the two spectra. The Jet Propulsion Laboratory, Pasadena, CA manages the mission for NASA's Office of Space Science, Washington, DC. 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. |
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Europa and Callisto under th
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PIA02861
Sol (our sun)
Imaging Science Subsystem
| Title |
Europa and Callisto under the watchful gaze of Jupiter |
| Original Caption Released with Image |
One moment in an ancient, orbital dance is caught in this color picture taken by NASA's Cassini spacecraft on Dec. 7, 2000, just as two of Jupiter's four major moons, Europa and Callisto, were nearly perfectly aligned with each other and the center of the planet. The distances are deceiving. Europa, seen against Jupiter, is 600,000 kilometers (370,000 miles) above the planet's cloud tops. Callisto, at lower left, is nearly three times that distance from the cloud tops. Europa is a bit smaller than Earth's Moon and has one of the brightest surfaces in the solar system. Callisto is 50 percent bigger -- roughly the size of Saturn's largest satellite, Titan -- and three times darker than Europa. Its brightness had to be enhanced in this picture, relative Europa's and Jupiter's, in order for Callisto to be seen in this image. Europa and Callisto have had very different geologic histories but share some surprising similarities, such as surfaces rich in ice. Callisto has apparently not undergone major internal compositional stratification, but Europa's interior has differentiated into a rocky core and an outer layer of nearly pure ice. Callisto's ancient surface is completely covered by large impact craters: The brightest features seen on Callisto in this image were discovered by the Voyager spacecraft in 1979 to be bright craters, like those on our Moon. In contrast, Europa's young surface is covered by a wild tapestry of ridges, chaotic terrain and only a handful of large craters. Recent data from the magnetometer carried by the Galileo spacecraft, which has been in orbit around Jupiter since 1995, indicate the presence of conducting fluid, most likely salty water, inside both worlds. Scientists are eager to discover whether the surface of Saturn's Titan resembles that of Callisto or Europa, or whether it is entirely different when Cassini finally reaches its destination in 2004. Cassini is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the Cassini mission for NASA's Office of Space Science, Washington, D.C. |
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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 Asgard Region as Vi
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PIA00839
Jupiter
Near Infrared Mapping Spectr
…
| Title |
Callisto Asgard Region as Viewed by NIMS |
| Original Caption Released with Image |
This view of Callisto's Asgard multi-ring structure was taken by the Near Infrared Mapping Spectrometer (NIMS) 90 minutes before closest approach. The false color image shows surface compositional differences, white=more ice, blue=less ice. The large bright/white area is the palimpsest or center of Asgard. The smaller bright area is Tornasuk, a crater with a diameter of about 70 km. The infrared spectrum shows that Tornasuk exhibits a greater abundance of water ice compared with the surrounding region. This may be due to impact excavation revealing a more ice-rich subsurface and suggesting that the darker material is a relatively thin surface covering. This covering could be either impact debris material or a lag deposit of existing material from which the ice has evaporated away. 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. |
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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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