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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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| Description |
Eye on Ganymede |
| Full Description |
Jupiter casts a baleful eye toward the moon Ganymede in this enhanced-contrast image from NASA's Cassini spacecraft. Jupiter's 'eye', the Great Red Spot, was captured just before disappearing around the eastern edge of the planet. The furrowed eyebrow above and to the left of the spot is a turbulent wake region caused by westward flow that has been deflected to the north and around the Red Spot. The smallest features visible are about 240 kilometers (150 miles) across. Within the band south of the Red Spot are a trio of white ovals, high pressure counterclockwise-rotating regions that are dynamically similar to the Red Spot. The dark filamentary features interspersed between white ovals are probably cyclonic circulations and, unlike the ovals, are rotating clockwise. Jupiter's equatorial zone stretching across the planet north of the Spot appears bright white, with gigantic plume clouds spreading out from the equator both to the northeast and to the southeast in a chevron pattern. This zone looks distinctly different than it did during the Voyager flyby 21 years ago. Then, its color was predominantly brown and the only white plumes conspicuous against the darker material beneath them were oriented southwest-to-northeast. Ganymede is Jupiter's largest moon, about 50 percent larger than our own Moon and larger than the planet Mercury. The visible details in this image are different geological terrains. Dark areas tend to be older and heavily cratered, brighter areas are younger and less cratered. Cassini images of Ganymede and Jupiter's other large moons taken near closest approach on Dec. 30 will have resolutions about four times better than that seen here. This image is a color composite of ones taken with different filters by Cassini's narrow-angle camera on Nov. 18, 2000, processed to enhance contrast. 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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| 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 |
The solar system's largest moon, Ganymede, is captured here alongside the planet Jupiter in a color picture taken by NASA's Cassini spacecraft on Dec. 3, 2000. Ganymede is larger than the planets Mercury and Pluto and Saturn's largest moon, Titan. Both Ganymede and Titan have greater surface area than the entire Eurasian continent on our planet. Cassini was 26.5 million kilometers (16.5 million miles) from Ganymede when this image was taken. The smallest visible features are about 160 kilometers (about 100 miles) across. The bright area near the south (bottom) of Ganymede is Osiris, a large, relatively new crater surrounded by bright icy material ejected by the impact which created it. Elsewhere, Ganymede displays dark terrains that NASA's Voyager and Galileo spacecraft have shown to be old and heavily cratered. The brighter terrains are younger and laced by grooves. Various kinds of grooved terrains have been seen on many icy moons in the solar system. These are believed to be the surface expressions of warm, pristine, water-rich materials that moved to the surface and froze. Ganymede has proven to be a fascinating world, the only moon known to have a magnetosphere, or magnetic environment, produced by a convecting metal core. The interaction of Ganymede's and Jupiter's magnetospheres may produce dazzling variations in the auroral glows in Ganymede's tenuous atmosphere of oxygen. 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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Transition on Enceladus
| Description |
Transition on Enceladus |
| Full Description |
This view of Saturn's moon Enceladus shows an area that has undergone a very intriguing -- and in places puzzling -- sequence of events. The craters here are subdued, as seen elsewhere on Enceladus, and most, but not all, are older than the fractures. Fracturing has occurred at a wide variety of scales, from the wide rift running through the center of the image to much narrower sets of shorter fractures that crosscut the craters (and each other) to the left. The image has been rotated so that north on Enceladus is up. This region is a transition from cratered to wrinkled terrain. Westward (left) of the central rift that divides the two regions are relatively parallel grooves and ridges that are reminiscent of terrain on Jupiter's large moon Ganymede. Very few craters are seen in this area of Enceladus. Eastward (right) of the large rift the terrain becomes more cratered, although the craters are quite degraded (meaning soft and shallow in appearance). A prominent fracture runs north-south to the center of the image, then turns sharply to the southwest, cutting across cratered terrain, the large rift, and the grooved terrain. This behavior signifies that it is one of the youngest features in this image. The image was taken in visible light with the narrow angle camera from a distance of about 14,000 kilometers (8,800 miles) and from Enceladus and at a Sun-Enceladus-spacecraft, or phase, angle of 44 degrees. Pixel scale in the image is about 85 meters (280 feet) per pixel. A stereo anaglyph version of the scene is also available (see Transition on Enceladus (3-D)). The images have been contrast-enhanced to aid visibility. The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the mission for NASA's Science Mission Directorate, Washington, D.C. The Cassini orbiter and its two onboard cameras were designed, developed and assembled at JPL. The imaging team is based at the Space Science Institute, Boulder, Colo. For more information about the Cassini-Huygens mission visit http://saturn.jpl.nasa.gov . For additional images visit the Cassini imaging team homepage http://ciclops.org . *Credit:* NASA/JPL/Space Science Institute |
| Date |
March 24, 2005 |
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Transition on Enceladus (3-D
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| Description |
Transition on Enceladus (3-D) |
| Full Description |
This stereo anaglyph of Saturn's moon Enceladus shows an area that has undergone a very intriguing -- and in places puzzling -- sequence of events. The craters here are subdued, as seen elsewhere on Enceladus, and most, but not all, are older than the fractures. Fracturing has occurred at a wide variety of scales, from the wide rift running through the center of the image to much narrower sets of shorter fractures that crosscut the craters (and each other) to the left. The anaglyph has been rotated so that north on Enceladus is up. This region is a transition from cratered to wrinkled terrain. Westward (left) of the central rift that divides the two regions are relatively parallel grooves and ridges that are reminiscent of terrain on Jupiter's large moon Ganymede. Very few craters are seen in this area of Enceladus. Eastward (right) of the large rift the terrain becomes more cratered, although the craters are quite degraded (meaning soft and shallow in appearance). A prominent fracture runs north-south to the center of the image, then turns sharply to the southwest, cutting across cratered terrain, the large rift, and the grooved terrain. This behavior signifies that it is one of the youngest features in this image. The images for this anaglyph were taken in visible light with Cassini's narrow-angle camera, at distances from Enceladus ranging from about 25,700 kilometers (16,000 miles, red-colored image) to 14,000 kilometers (8,800 miles, blue-colored image) and at a Sun-Enceladus-spacecraft, or phase, angle ranging from 46 to 44 degrees. Pixel scale in the red image was 150 meters (490 feet) per pixel. Scale in the blue image was 85 meters (280 feet) per pixel. A separate, non-stereo version of the scene, showing only the red image, is also available (see Transition on Enceladus (3-D)). The images have been contrast-enhanced to aid visibility. The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the mission for NASA's Science Mission Directorate, Washington, D.C. The Cassini orbiter and its two onboard cameras were designed, developed and assembled at JPL. The imaging team is based at the Space Science Institute, Boulder, Colo. For more information about the Cassini-Huygens mission visit http://saturn.jpl.nasa.gov . For additional images visit the Cassini imaging team homepage http://ciclops.org . *Credit:* NASA/JPL/Space Science Institute |
| Date |
March 24, 2005 |
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| 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 |
Auroral "Footprints" of Jupiter's Moons February 27, 2002 A drawing illustrates how flows of electrons steered by Jupiter's magnetic field connect three of Jupiter's large moons with the upper atmosphere near Jupiter's north and south poles. The currents stimulate ultraviolet aurora glows in Jupiter's upper atmosphere. Observations with NASA's Hubble Space Telescope, coordinated with the late 2000 flyby of Jupiter by NASA's Cassini spacecraft, captured those auroral footprints for the moons Io (left), Europa (right) and Ganymede (center). In the illustration, Jupiter's magnetic field lines are presented in blue, the moons' orbital paths around Jupiter in yellow. Pink loops from each of the moons to Jupiter's poles depict the flux tubes that are the paths of powerful electric currents. The Space Telescope Science Institute, Baltimore, Md., manages space operations for Hubble for NASA's Office of Space Science, Washington, D.C. The institute is operated by the Association of Universities for Research in Astronomy, Inc., for NASA, under contract with the Goddard Space Flight Center, Greenbelt, Md. The Hubble Space Telescope is a project of international cooperation between NASA and the European Space Agency. 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. Credit: NASA/John Spencer, Lowell Observatory and John Clarke, Boston University More information about the Cassini and Galileo joint observations of the Jupiter system is available online at: http://www.jpl.nasa.gov/jupiterflyby. 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 Galileo and Cassini missions for NASA's Office of Space Science, Washington, D.C. |
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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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One View, Multiple Worlds
| Description |
One View, Multiple Worlds: Tethys, Epimetheus and Titan |
| Full Description |
Three very different worlds crowd the frame in this unique view from the Cassini spacecraft, which although partly overexposed, provides a splendid look at several major targets of interest for the mission. Titan (at the top) has a thick, hazy atmosphere. Cassini has observed it to be a world where complex geological and atmospheric processes are occurring. At 5,150 kilometers (3,200 miles) across, it is Saturn's largest moon, and is the second largest moon in the solar system, after Jupiter's moon Ganymede (5,262 kilometers, or 3,270 miles across). Tethys (at the bottom) has been battered by impacts over the eons, and some of its many craters are visible in this image. Tethys (1,071 kilometers, or 665 miles across) is one of Saturn's major icy moons, having a density close to that of water. This moon shows evidence that icy tectonic processes have occurred on its frozen surface, such as the immense canyon system called Ithaca Chasma. Epimetheus (center) is one of Saturn's "ring moons": small, porous bodies that orbit within or just beyond the rings. Cassini acquired the closest-ever view of cratered Epimetheus (116 kilometers, or 72 miles across) in March, 2005. Also near center are Saturn's F ring and the outer edge of the A ring to the left. In addition to the F ring's usually bright core, several other ringlets are resolved here, giving the ring a soft, wispy character that shows contrast with the more sharply defined A ring. Appearances can be deceiving in two dimensional images like this one where it is difficult to tell which objects are in the foreground and which are farther away. In this scene, Tethys is the closest object to Cassini, at 1.2 million kilometers (700,000 miles) away. Epimetheus is on the near side of the rings and is 1.4 million kilometers (900,000 miles) distant. The giant moon Titan is 2.7 million kilometers (1.7 million miles) away, more than twice as far from Cassini as Tethys. This view is a mosaic of two images taken in visible light with the Cassini spacecraft narrow-angle camera on Feb. 19, 2005. The image scale in the scene ranges from 16 kilometers (10 miles) per pixel on Titan to 7 kilometers (4 miles) per pixel on Tethys. 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 . The Cassini imaging team homepage is at http://ciclops.org . Credit: NASA/JPL/Space Science Institute |
| Date |
June 9, 2005 |
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The Face of Phoebe
| Description |
The Face of Phoebe |
| Full Description |
Phoebe's true nature is revealed in startling clarity in this mosaic of two images taken during Cassini's flyby on June 11, 2004. The image shows evidence for the emerging view that Phoebe may be an ice-rich body coated with a thin layer of dark material. Small bright craters in the image are probably fairly young features. This phenomenon has been observed on other icy satellites, such as Ganymede at Jupiter. When impactors slammed into the surface of Phoebe, the collisions excavated fresh, bright material -- probably ice -- underlying the surface layer. Further evidence for this can be seen on some crater walls where the darker material appears to have slid downwards, exposing more light-colored material. Some areas of the image that are particularly bright - especially near lower right - are over-exposed. An accurate determination of Phoebe's density - a forthcoming result from the flyby - will help Cassini mission scientists understand how much of the little moon is comprised of ices. This spectacular view was obtained at a phase, or Sun-Phoebe-spacecraft, angle of 84 degrees, and from a distance of approximately 32,500 kilometers (20,200 miles). The image scale is approximately 190 meters (624 feet) per pixel. No enhancement was performed on this image. The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the Cassini-Huygens mission for NASA's Office of Space Science, Washington, D.C. The Cassini orbiter and its two onboard cameras were designed, developed and assembled at JPL. The imaging team is based at the Space Science Institute, Boulder, Colo. For more information about the Cassini-Huygens mission visit, http://saturn.jpl.nasa.gov and the Cassini imaging team home page, http://ciclops.org . Image Credit: NASA/JPL/Space Science Institute |
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| Description |
Here on the Gallery page you can find the very latest images, videos and products from the Cassini-Huygens mission to Saturn, including the spectacular launch, spacecraft assembly and the exciting trip to Saturn. |
| Full Description |
Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, Calif., manages the Cassini mission for NASA's Office of Space Science, Washington, D.C. Credit: NASA/JPL/University of Arizona (PIA02826) For higher resolution, click here., These two images, taken by NASA's Cassini spacecraft, show Jupiter in a near-infrared wavelength, and catch Europa, one of Jupiter's largest moons, at different phases. Cassini's narrow-angle camera took both images, the upper one from a distance of 69.9 million kilometers (43.4 million miles) on Oct. 17, 2000, and the lower one from a distance of 65.1 million kilometers (40.4 million miles) on Oct. 22, 2000. Both were taken at a wavelength of 727 nanometers, which is in the near-infrared region of the electromagnetic spectrum. The camera's 727-nanometer filter accepts only a narrow spectral range centered on a relatively strong absorption feature due to methane gas. In this spectral region, the amount of light reflected by Jupiter's clouds is only half that reflected in a nearby spectral region outside the methane band. The features that are brightest in these images are the highest and thickest clouds, such as the Great Red Spot and the band of clouds girding the equator, as these scatter sunlight back to space before it has a chance to be absorbed by the methane gas in the atmosphere. This stratigraphic effect can be seen even more prominently in an image released on Oct. 23, 2000, taken in the stronger methane band at 889 nanometers, in which the only bright features are the highest hazes over the equator, the poles and the Great Red Spot. By comparing images taken in the 727 nanometer filter with others taken at 889 nanometers and at a weaker methane band at 619 nanometers, researchers will probe the heights and thickness of clouds in Jupiter's atmosphere. Europa, a satellite of Jupiter about the size of Earth's Moon, is visible to the left of Jupiter in the upper image, and in front of the planet in the lower image. Another of Jupiter's Galilean satellites, Ganymede, which is larger than the planet Mercury, is to the right in the upper image, with brightness variations visible across its surface. In the upper image, Europa is caught entering Jupiter's shadow, and hence appears as a bright crescent, in the lower image, it is seen about one-and-a-half orbits later, in transit across the face of the planet. Because there is neither methane nor any strong absorber in this spectral region on the surface of Europa, it appears strikingly white and bright compared to Jupiter. Imaging observations of the moons Europa, Io and Ganymede entering and passing through Jupiter's shadow are planned for the two-week period surrounding Cassini's closest approach on Dec. 30, 2000. The purpose of these eclipse observations is to detect and measure the variability of emissions that arise from the interaction of the satellites' tenuous atmospheres with the charged particles trapped in Jupiter's magnetic field. At the times these images were taken, Cassini was about 3.3 degrees above Jupiter's equatorial plane, and the Sun-Jupiter-spacecraft angle was about 20 degrees. Cassini is a cooperative project of NASA, the European Space Agency and the Italian |
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The Face of Phoebe
| title |
The Face of Phoebe |
| date |
06.11.2004 |
| description |
Phoebe's true nature is revealed in startling clarity in this mosaic of two images taken during Cassini's flyby on June 11, 2004. The image shows evidence for the emerging view that Phoebe may be an ice-rich body coated with a thin layer of dark material. Small bright craters in the image are probably fairly young features. This phenomenon has been observed on other icy satellites, such as Ganymede at Jupiter. When impactors slammed into the surface of Phoebe, the collisions excavated fresh, bright material -- probably ice -- underlying the surface layer. Further evidence for this can be seen on some crater walls where the darker material appears to have slid downwards, exposing more light-colored material. Some areas of the image that are particularly bright - especially near lower right - are over-exposed. An accurate determination of Phoebe's density -- a forthcoming result from the flyby -- will help Cassini mission scientists understand how much of the little moon is comprised of ices. This spectacular view was obtained at a phase, or Sun-Phoebe-spacecraft, angle of 84 degrees, and from a distance of approximately 32,500 kilometers (20,200 miles). The image scale is approximately 190 meters (624 feet) per pixel. No enhancement was performed on this image. The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the Cassini-Huygens mission for NASA's Office of Space Science, Washington, D.C. The Cassini orbiter and its two onboard cameras, were designed, developed and assembled at JPL. The imaging team is based at the Space Science Institute, Boulder, Colo. For more information, about the Cassini-Huygens mission visit, http://saturn.jpl.nasa.gov [ http://saturn.jpl.nasa.gov/ ] and the Cassini imaging team home page, http://ciclops.org [ http://ciclops.org/ ]. Image Credit: NASA/JPL/Space Science Institute |
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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 Aurora
| title |
Jupiter Aurora |
| description |
In this Hubble telescope picture, a curtain of glowing gas is wrapped around Jupiter's north pole like a lasso. This curtain of light, called an aurora, is produced when high-energy electrons race along the planet's magnetic field and into the upper atmosphere where they excite atmospheric gases, causing them to glow. The aurora resembles the same phenomenon that crowns Earth's polar regions. But this Hubble image, taken in ultraviolet light, also shows the glowing "footprints" of three of Jupiter's largest moons: Io, Ganymede, and Europa. Spanning next two months in 2004, Jupiter's aurora will be scrutinized by two observatories: the Hubble telescope and the Cassini spacecraft, which will fly by the planet on its voyage to Saturn. *Image Credit*: John Clarke (University of Michigan) and NASA |
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Ganymede's Shadow
| title |
Ganymede's Shadow |
| date |
01.09.2007 |
| description |
The New Horizons Long Range Reconnaissance Imager (LORRI) took this photo of Jupiter at 20:42:01 UTC on January 9, 2007, when the spacecraft was 80 million kilometers (49.6 million miles) from the giant planet. The volcanic moon Io is to the left of the planet, the shadow of the icy moon Ganymede moves across Jupiter's northern hemisphere. Ganymede's average orbit distance from Jupiter is about 1 million kilometers (620,000 miles), Io's is 422,000 kilometers (262,000 miles). Both Io and Ganymede are larger than Earth's moon, Ganymede is larger than the planet Mercury. Image Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute |
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Moons around Jupiter
| title |
Moons around Jupiter |
| date |
01.09.2007 |
| description |
The New Horizons Long Range Reconnaissance Imager (LORRI) took this photo of Jupiter at 20:42:01 UTC on January 9, 2007, when the spacecraft was 80 million kilometers (49.6 million miles) from the giant planet. The volcanic moon Io is to the left of the planet, the shadow of the icy moon Ganymede moves across Jupiter's northern hemisphere. Ganymede's average orbit distance from Jupiter is about 1 million kilometers (620,000 miles), Io's is 422,000 kilometers (262,000 miles). Both Io and Ganymede are larger than Earth's moon, Ganymede is larger than the planet Mercury. Image Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute |
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Ganymede
| title |
Ganymede |
| date |
02.27.2007 |
| description |
This is New Horizons' best image of Ganymede, Jupiter's largest moon, taken with the spacecraft's Long Range Reconnaissance Imager (LORRI) camera at 10:01 Universal Time on February 27 from a range of 3.5 million kilometers (2.2 million miles). The longitude of the disk center is 38 degrees West and the image scale is 17 kilometers (11 miles) per pixel. Dark patches of ancient terrain are broken up by swaths of brighter, younger material, and the entire icy surface is peppered by more recent impact craters that have splashed fresh, bright ice across the surface. With a diameter of 5,268 kilometers (3.273 miles), Ganymede is the largest satellite in the solar system. This is one of a handful of Jupiter system images already returned by New Horizons during its close approach to Jupiter. Most of the data being gathered by the spacecraft are stored onboard and will be downlinked to Earth during March and April 2007. Image Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute |
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Io and Ganymede
| title |
Io and Ganymede |
| date |
01.17.2007 |
| description |
The New Horizons Long Range Reconnaissance Imager (LORRI) took this 4-millisecond exposure of Jupiter and two of its moons at 01:41:04 UTC on January 17, 2007. The spacecraft was 68.5 million kilometers (42.5 million miles) from Jupiter, closing in on the giant planet at 41,500 miles (66,790 kilometers) per hour. The volcanic moon Io is the closest planet to the right of Jupiter, the icy moon Ganymede is to Io's right. The shadows of each satellite are visible atop Jupiter's clouds, Ganymede's shadow is draped over Jupiter's northwestern limb. Ganymede's average orbit distance from Jupiter is about 1.07 million kilometers (620,000 miles), Io's is 422,000 kilometers (262,000 miles). Both Io and Ganymede are larger than Earth's moon, Ganymede is larger than the planet Mercury. Image Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute |
|
Storms and Moons
| title |
Storms and Moons |
| date |
01.24.2007 |
| description |
The New Horizons Long Range Reconnaissance Imager (LORRI) took this 2-millisecond exposure of Jupiter at 04:41:04 UTC on January 24, 2007. The spacecraft was 57 million kilometers (35.3 million miles) from Jupiter, closing in on the giant planet at 41,500 miles (66,790 kilometers) per hour. At right are the moons Io (bottom) and Ganymede, Ganymede's shadow creeps toward the top of Jupiter's northern hemisphere. Two of Jupiter's largest storms are visible, the Great Red Spot on the western (left) limb of the planet, trailing the Little Red Spot on the eastern limb, at slightly lower latitude. The Great Red Spot is a 300-year old storm more than twice the size of Earth. The Little Red Spot, which formed over the past decade from the merging of three smaller storms, is about half the size of its older and "greater" counterpart. Image Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute |
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Hubble Finds Ozone on Jupite
…
| title |
Hubble Finds Ozone on Jupiter's Moon Ganymede |
| description |
Though ozone may be diminishing on Earth, it is being manufactured one-half billion miles away, on Jupiter's largest satellite, Ganymede. NASA's Hubble Space Telescope found ozone's spectral "fingerprint" during observations of Ganymede made by Keith Noll and colleagues at the Space Telescope Science Institute in Baltimore, Maryland. These Hubble Faint Object Spectrograph results were presented at the American Astronomical Society's 27th Annual Meeting of the Division of Planetary Sciences in Kona, Hawaii. *Image Credit*: NASA |
|
Ganymede Topography
| title |
Ganymede Topography |
| description |
This perspective view, simulating a low altitude flight over the surface of Ganymede, was made possible by topographic analysis of stereo images of the Sippar Sulcus region. Such a view was made possible when Galileo passed Ganymede in May 1997, providing a virtual second "eye" to Voyager's first view in 1979. Because this view covers a large area, it reveals that younger, smoother terrains are low-lying relative to older, heavily faulted terrains. The consistently low elevations of these smooth deposits has been cited as evidence for flooding of parts of Ganymede by low-viscosity lavas, most likely liquid water or water-ice slush. This view is centered at 35 degrees south, 180 degrees west. The smallest features visible are roughly 350 to 400 meters (1,150 to 1,300 feet) across. This image was prepared by the Lunar and Planetary Institute, Houston, and included in a report by Dr. Paul Schenk et al. in the March 1, 2001, edition of the journal Nature. *Image Credit*: NASA and Lunar and Planetary Institute |
|
Many Worlds, Many Craters
| title |
Many Worlds, Many Craters |
| description |
A comparison of ~30-kilometer-diameter impact craters on several planetary bodies. All craters are shown at the same scale and have been rotated so that the light source is from the left. This rotation puts north at the bottom of the images of the lunar crater and the Ganymede crater. Names and locations of the four craters are as follows: Golubkhina (Venus), 60.30N, 286.40E, Kepler (Moon), 8.10N, 38.10W, (Mars), 20.80S, 53.60E, (Ganymede), 29.80S, 136.00W. *Image Credit*: Image of Ganymede Crater contributed by Paul Schenk (Lunar and Planetary Institute). Image of Mars crater obtained from the Mars Multi-Scale Map, Calvin Hamilton (Los Alamos National Laboratory). Images of lunar and venusian craters from Robert Herrick (Lunar and Planetary Institute). |
|
Ganymede's Nergal Crater
| title |
Ganymede's Nergal Crater |
| date |
09.06.1996 |
| description |
Two impact craters surrounded by an unusual ejecta blanket dominate this high-resolution image of the surface of Jupiter's moon Ganymede. NASA's Galileo spacecraft photographed this region as it passed Ganymede during its second orbit through the jovian system. North is to the top of the picture, and the Sun illuminates the surface from the southeast. Nergal, the larger crater, is about 8 kilometers in diameter, while the smaller (unnamed) crater to its west is 3 kilometers across. The craters are situated in a region of bright grooved terrain named Byblus Sulcus, located in the northern part of Marius Regio at 390N latitude and 2010W longitude. The distinctive ejecta blanket that surrounds them is darker nearer the craters and brighter further away. The inner region of the ejecta is characterized by a lobate appearance indicative of the flow of a liquid (or slushy) substance over the surface. The flow was probably icy surface material melted by the energy released during the impact that formed the crater. The picture covers an area about 48 by 34 kilometers across at a resolution of 86 meters per picture element. The image was taken on September 6, 1996, by the Solid-State Imaging System onboard the Galileo spacecraft. *Image Credit*: Brown University |
|
Ganymede's Khensu Crater
| title |
Ganymede's Khensu Crater |
| date |
09.06.1996 |
| description |
The dark-floored crater Khensu is the target of this image of Ganymede. The Solid-State Imaging System onboard the Galileo spacecraft imaged this region as it passed Ganymede during its second orbit through the jovian system. Khensu is located at 20N latitude and 1530W longitude in a region of bright terrain known as Uruk Sulcus, and is about 13 kilometers in diameter. Like some other craters on Ganymede, it possesses an unusually dark floor and a bright ejecta blanket. The dark component may be residual material from the impactor that formed the crater. Another possibility is that the impactor may have punched through the bright surface to reveal a dark layer beneath. Another large crater named El is partly visible in the top righthand corner of the image. This crater is 54 kilometers in diameter and has a small "pit" in its center. Craters with such a "central pit" are common across Ganymede and are especially intriguing since they may reveal secrets about the structure of the satellite's shallow subsurface. North is to the upper left of the picture, and the Sun illuminates the surface from nearly overhead. The image covers an area about 100 by 86 kilometers across at a resolution of 111 meters per picture element. The image was taken on September 6, 1996, by the Solid-State Imaging System onboard the Galileo spacecraft. *Image Credit*: Brown University |
|
Family Portrait of Jupiter's
…
| 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 |
|
Eyeing Ganymede
| title |
Eyeing Ganymede |
| date |
11.18.2000 |
| description |
Jupiter casts a baleful eye toward the moon Ganymede in this enhanced-contrast image from NASA's Cassini spacecraft. Jupiter's "eye', the Great Red Spot, was captured just before disappearing around the eastern edge of the planet. The furrowed eyebrow above and to the left of the spot is a turbulent wake region caused by westward flow that has been deflected to the north and around the Red Spot. The smallest features visible are about 240 kilometers (150 miles) across. Within the band south of the Red Spot are a trio of white ovals, high pressure counterclockwise-rotating regions that are dynamically similar to the Red Spot. The dark filamentary features interspersed between white ovals are probably cyclonic circulations and, unlike the ovals, are rotating clockwise. Jupiter's equatorial zone stretching across the planet north of the Spot appears bright white, with gigantic plume clouds spreading out from the equator both to the northeast and to the southeast in a chevron pattern. This zone looks distinctly different than it did during the Voyager flyby 21 years ago. Then, its color was predominantly brown and the only white plumes conspicuous against the darker material beneath them were oriented southwest-to-northeast. Ganymede is Jupiter's largest moon, about 50 percent larger than our own Moon and larger than the planet Mercury. The visible details in this image are different geological terrains. Dark areas tend to be older and heavily cratered, brighter areas are younger and less cratered. Cassini images of Ganymede and Jupiter's other large moons taken near closest approach on Dec. 30 will have resolutions about four times better than that seen here. This image is a color composite of ones taken with different filters by Cassini's narrow-angle camera on Nov. 18, 2000, processed to enhance contrast. 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. *Image Credit*: NASA/JPL/University of Arizona |
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Jupiter and the Galilean Sat
…
| 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 |
|
Osiris Crater
| title |
Osiris Crater |
| description |
View of the bright rayed crater Osiris (40 S, 161 W) on Ganymede. North is to the bottom of the picture and the sun illuminates the surface from the left. The finest details that can be discerned in this picture are about 6.7 km across. The time is 8:45:09 UT on June 26, 1996. *Image Credit*: NASA |
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Ganymede's Northern Limb
| title |
Ganymede's Northern Limb |
| description |
View of the Northern limb region on Ganymede showing the Galileo Regio region. North is to the bottom of the picture and the sun illuminates the surface from the left. The finest details that can be discerned in this picture are about 6.7 km across. The time is 8:45:09 UT on June 26, 1996. *Image Credit*: NASA |
|
Ganymede's Northern Terminat
…
| title |
Ganymede's Northern Terminator |
| description |
View of the Northern terminator region on Ganymede showing the Uruk Sulcus region. North is to the bottom of the picture and the sun illuminates the surface from the left. The finest details that can be discerned in this picture are about 6.7 km across. The time is 8:45:09 UT on June 26, 1996. *Image Credit*: NASA |
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Ganymede's Bright Limb
| title |
Ganymede's Bright Limb |
| description |
View of the bright limb of Ganymede showing a field of bright rayed craters in the satellites equatorial region and southern hemisphere. North is to the bottom of the picture and the sun illuminates the surface from the left. The finest details that can be discerned in this picture are about 6.7 kilometers across. The Universal Time is 8:45:09 UT on June 26, 1996. *Image Credit*: NASA |
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Galileo Regio's Furrowed Reg
…
| title |
Galileo Regio's Furrowed Region |
| description |
View of the Galileo Regio region on Ganymede showing fine details of the Galileo image fit into the larger scale, but much lower resolution view of the region taken 17 years earlier by Voyager. The broad curved furrow patterns are characteristic of the darker regions of this moon. North is to the top of the picture and the sun illuminates the surface from almost overhead in the Galileo picture. *Image Credit*: NASA |
|
Triple Eclipse
| title |
Triple Eclipse |
| description |
At first glance, Jupiter looks like it has a mild case of the measles. Five spots - one colored white, one blue, and three black are scattered across the upper half of the planet. Closer inspection by NASA's Hubble Space Telescope reveals that these spots are actually a rare alignment of three of Jupiter's largest moons - Io, Ganymede, and Callisto - across the planet's face. In this image, the telltale signatures of this alignment are the shadows [the three black circles] cast by the moons. Io's shadow is located just above center and to the left, Ganymede's on the planet's left edge, and Callisto's near the right edge. Only two of the moons, however, are visible in this image. Io is the white circle in the center of the image, and Ganymede is the blue circle at upper right. Callisto is out of the image and to the right. On Earth, we witness a solar eclipse when our Moon's shadow sweeps across our planet's face as it passes in front of our Sun. Jupiter, however, has four moons roughly the same size as Earth's Moon. The shadows of three of them occasionally sweep simultaneously across Jupiter. The image was taken March 28, 2004, with Hubble's Near Infrared Camera and Multi-Object Spectrometer. Seeing three shadows on Jupiter happens only about once or twice a decade. Why is this triple eclipse so unique? Io, Ganymede, and Callisto orbit Jupiter at different rates. Their shadows likewise cross Jupiter's face at different rates. For example, the outermost moon Callisto orbits the slowest of the three satellites. Callisto's shadow moves across the planet once for every 20 shadow crossings of Io. Add the crossing rate of Ganymede's shadow and the possibility of a triple eclipse becomes even more rare. Viewing the triple shadows in 2004 was even more special, because two of the moons were crossing Jupiter's face at the same time as the three shadows. Jupiter appears in pastel colors in this photo because the observation was taken in near-infrared light. Astronomers combined images taken in three near-infrared wavelengths to make this color image. The photo shows sunlight reflected from Jupiter's clouds. In the near infrared, methane gas in Jupiter's atmosphere limits the penetration of sunlight, which causes clouds to appear in different colors depending on their altitude. Studying clouds in near-infrared light is very useful for scientists studying the layers of clouds that make up Jupiter's atmosphere. Yellow colors indicate high clouds, red colors lower clouds, and blue colors even lower clouds in Jupiter's atmosphere. The green color near the poles comes from a thin haze very high in the atmosphere. Ganymede's blue color comes from the absorption of water ice on its surface at longer wavelengths. Io's white color is from light reflected off bright sulfur compounds on the satellite's surface. In viewing this rare alignment, astronomers also tested a new imaging technique. To increase the sharpness of the near-infrared camera images, astronomers, speeded up Hubble's tracking system so that Jupiter traveled through the telescope's field of view much faster than normal. This technique allowed scientists to take rapid-fire snapshots of the planet and its moons. They then combined the images into one single picture to show more details of the planet and its moons. *Image Credit*: NASA, ESA, and E. Karkoschka (University of Arizona) |
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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 |
|
Voyager 1 Image of Ganymede
| Title |
Voyager 1 Image of Ganymede |
| Full Description |
Voyager 1 took this picture of Ganymede from a distance of 1.6 million miles. Ganymede is Jupiter's largest satellite with a radius of approximately 2600 kilometers, about 1.5 times that of Earth's Moon. Ganymede is the seventh and largest of Jupiter's known satellites and is the third of the Galilean moons. Discovered in 1610 by Galileo and Marius, Ganymede is the largest satellite in the Solar System. It was named after the Greek mythical character, Ganymede, a handsome Trojan boy that Zeus took to Olympus to be a cupbearer for the gods (one of the only humans in Greek mythology who became immortal). Ganymede is larger than Mercury but has only half Mercury's mass. It has a bulk density of only two grams per cubic centimeter, almost half that of Earth's Moon. Ganymede is most likely composed of a mixture of rock and ice. The long white filaments resemble rays associated with impacts on the lunar surface. The various colors of different regions probably represent differing surface materials. Several dots of a single color (blue, green, and orange) on the picture are the result of markings on the camera used for pointing determinations and are not physical markings. Voyager scientists discovered that Ganymede has its own magnetosphere embedded inside Jupiter's large one. JPL manages and controls the Voyager Project for NASA's Office of Space Science. |
| Date |
03/04/1979 |
| NASA Center |
Jet Propulsion Laboratory |
|
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 |
|
A Polar Crater on Ganymede
| Title |
A Polar Crater on Ganymede |
| Description |
This circular 36 kilometer (22 mile) diameter impact crater near the north pole of Jupiter's moon Ganymede has a floor that is partially brightened. On September 6, 1996, NASA's Galileo spacecraft obtained images of an 18 kilometer (11 miles) wide swath through this area. The Galileo data, acquired at a resolution of 46 meters (151 feet) pixel (picture element), is shown overlain on data obtained by NASA's Voyager spacecraft in 1979. In Voyager data the crater was thought to be flooded by icy volcanism, but in Galileo data it is seen to be brightened by frost deposition. The Voyager data, taken at a resolution of 1.3 kilometers (0.8 miles) per pixel, shows a circular feature with a bright deposit on the northern half of its floor. North is toward the top of the picture. Illumination in the image is from the southeast, and frost appears to be collecting on north facing slopes of ridges and crater rims. Fractures cross the floor of the large crater, and the northeastern rim displays two large blocks of ice which have collapsed off the side of the steep crater wall. The Galileo images were taken by the Solid State Imaging (CCD) system at a range of about 2243 kilometers (1391 miles) from the surface of Ganymede. The Jet Propulsion Laboratory, Pasadena, CA manages the Galileo mission for NASA's Office of Space Science, Washington, DC. JPL is an operating division of California Institute of Technology (Caltech). This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo mission home page at URL http://galileo.jpl.nasa.gov. Background information and educational context for the images can be found at URL http://www.jpl.nasa.gov/galileo/sepo |
| Date |
03.25.1997 |
|
Bright and Dark Slopes on Ga
…
| Title |
Bright and Dark Slopes on Ganymede |
| Description |
Ridges on the edge of Ganymede's north polar cap show bright east-facing slopes and dark west-facing slopes with troughs of darker material below the larger ridges. North is to the top. The bright slopes may be due to grain size differences, differences in composition between the original surface and the underlying material, frost deposition, or illumination effects. The large 2.4 kilometer (1.5 mile) diameter crater in this image shows frost deposits located on the north-facing rim slope, away from the sun. A smaller 675 meter (2200 foot) diameter crater in the center of the image is surrounded by a bright deposit which may be ejecta from the impact. Ejecta deposits such as this are uncommon for small craters on Ganymede. This image measures 18 by 19 kilometers (11 by 12 miles) and has a resolution of 45 meters (148 feet) per pixel. NASA's Galileo spacecraft obtained this image on September 6, 1996 during its second orbit around Jupiter. The Jet Propulsion Laboratory, Pasadena, CA manages the Galileo mission for NASA's Office of Space Science, Washington, DC. JPL is an operating division of California Institute of Technology (Caltech). This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo mission home page at URL http://galileo.jpl.nasa.gov. Background information and educational context for the images can be found at URL http://www.jpl.nasa.gov/galileo/sepo |
| Date |
03.27.1997 |
|
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 |
|
Ridges and Troughs in Sippar
…
| Title |
Ridges and Troughs in Sippar Sulcus, Ganymede |
| Description |
Embayment of ridges and troughs in a portion of the Sippar Sulcus area of Jupiter's moon Ganymede in this image from NASA's Galileo spacecraft is interpreted as evidence that the low-lying area was filled in by flooding with low-viscosity material, such as water or water-ice slush lavas. Bays of the material appeared to have formed in troughs (indicated by arrows) between the ridges. The smallest features visible are about 180 meters (590 feet) across. Analysis of such high-resolution images in combination with estimates of the features' relative elevations is helping scientists interpret the roles of volcanism and tectonics in creating the bright terrain on Ganymede. This image was prepared by the Lunar and Planetary Institute, Houston, and included in a report by Dr. Paul Schenk et al. in the March 1, 2001, edition of the journal Nature. 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. Images and data received from Galileo are posted on the Galileo mission home page at http://www.jpl.nasa.gov/galileo. Background information and educational context for the images can be found at http://www.jpl.nasa.gov/galileo/sepo . |
| Date |
03.13.2001 |
|
Saturn - Enceladus from a di
…
| Title |
Saturn - Enceladus from a distance of 119,000 kilometers (74,000 miles) |
| Description |
This Voyager 2 mosaic of Enceladus was made from images taken through the clear, violet and green filters Aug. 25, 1981, from a distance of 119,000 kilometers (74,000 miles). In many ways, the surface of this satellite of Saturn resembles that of Jupiter's Galilean satellite Ganymede. Enceladus, however, is only one-tenth Ganymede's size. Some regions of Enceladus show impact craters up to 35 kilometers (22 miles) in diameter, whereas other areas are smooth and uncratered. Linear sets of grooves tens of kilometers long traverse the surface and are probably faults resulting from deformation of the crust. The uncratered regions are geologically young and suggest that Enceladus has experienced a period of relatively recent internal melting. The rims of several craters near the lower center of the picture have been flooded by the smooth terrain. The satellite is about 500 kilometers (310 miles) in diameter and has the brightest and whitest surface of any of Saturn's satellites. Features as small as 2 kilometers (1.2 miles) are visible in this highest-resolution view of Enceladus. The Voyager project is managed for NASA by the Jet Propulsion Laboratory, Pasadena, Calif. |
| Date |
08.28.1981 |
|
Saturn - high-resolution fil
…
| Title |
Saturn - high-resolution filtered image of Enceladus |
| Description |
This high-resolution filtered image of Enceladus was made from several images obtained Aug. 25 by Voyager 2 from a range of 119,000 kilometers (74,000 miles). It shows further surface detail on this Saturnian moon (also viewed in the accompanying release P-23955C/BW, S-2-50, imaged about the same time). Enceladus is seen to resemble Jupiter's Galilean satellite Ganymede, which is, however, about 10 times larger. Faintly visible here in "Saturnshine" is the hemisphere turned away from the sun. The Voyager project is managed for NASA by the Jet Propulsion Laboratory, Pasadena, Calif. |
| Date |
08.28.1981 |
|
Saturn's satellite Dione
| Title |
Saturn's satellite Dione |
| Description |
This picture of Saturn's satellite Dione was taken by NASA's Voyager 1on Nov. 9, 1980 from a distance of 4.2 million kilometers (2.6 million miles). Light and dark patches are visible on the moon's surface, reminiscent of features seen on Jupiter's satellite Ganymede during Voyagers's Jupiter encounter last year. The bright spots may be rays emanating from impact craters on Dione's surface. Dione is about 1,110 kilometers in diameter, about one-third the size of Earth's Moon. The smallest detail seen in this image is about 78 kilometers (48 miles) across. The Voyager Project is managed for NASA by the Jet Propulsion Laboratory, Pasadena, Calif. |
| Date |
11.10.1980 |
|
Saturn's satellite Rhea
| Title |
Saturn's satellite Rhea |
| Description |
Bright streaks and blotches are visible against a darker back-ground on the surface of Saturn's satellite Rhea, seen in this Voyager 1 image taken Nov. 11, 1980 from a range of 1,925,000 kilometers (1,196,000 miles). Even the dark areas, thought to be water frost and ice, are fairly bright with about 50 percent reflectance. The bright streaks may be related to impacts by objects that throw out pulverized ice grains from beneath the ice-covered surface. Some of the bright streaks are not straight but have a curved appearance similar to the grooved, icy terrain on Jupiter's satellite Ganymede seen in Voyager photographs taken at this resolution. Scientists do knot yet know if a satellite of Rhea's size (approximately 1,500 kilometers or 900 miles in diameter) can have an active thermal history like Ganymede's, but higher resolution photographs taken by Voyager should reveal clues to its history. The Voyager Project is managed by the Jet Propulsion Laboratory for NASA. |
| Date |
11.11.1980 |
|
Sippar Sulcus, Ganymede
| Title |
Sippar Sulcus, Ganymede |
| Description |
These two frames, derived from images of Jupiter's moon Ganymede by NASA's Galileo and Voyager spacecraft, show bright terrain types and topography within an area called Sippar Sulcus in Ganymede's southern hemisphere. All three dominant structural styles of the bright regions -- grooved terrain, smooth terrain and reticulate terrain -- are represented. The left frame (a) is a mosaic of images taken by Galileo with a resolution of 180 meters (590 feet) per pixel superimposed on lower-resolution Voyager images. A swath of smooth terrain crosses the scene diagonally from upper right to center left. Irregularly shaped enclosures are interpreted as calderas, which, on Earth, are depressions typically caused by collapse of subsurface lava reservoirs. The numerous bright patches are due to secondary impacts from creation of a large crater, Osiris, which is out of the frame to the right. The right frame (b) shows a digital elevation model of the three-dimensional shape of the same scene. Relative elevation values have been color-coded and merged with the Galileo image mosaic. The inset shows a geological map highlighting areas of grooved terrain (g, black), reticulate terrain (r, gray), smooth terrain (s, white), calderas (hatched), and locations for higher-resolution views PIA-XXC [fig3a] (upper box) and PIA-XXD [fig3b] (lower box). These images were prepared by the Lunar and Planetary Institute, Houston, and included in a report by Dr. Paul Schenk et al. in the March 1, 2001, edition of the journal Nature. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the Galileo and Voyager missions for NASA's Office of Space Science, Washington, D.C. Images and data received from Galileo are posted on the Galileo mission home page at http://www.jpl.nasa.gov/galileo. Background information and educational context for the images can be found at http://www.jpl.nasa.gov/galileo/sepo. |
| Date |
03.13.2001 |
|
Erech Sulcus, Ganymede
| Title |
Erech Sulcus, Ganymede |
| Description |
Terrain units and topography of the area where a bright swath called Erech Sulcus intersects northern Sippar Sulcus on Jupiter's moon Ganymede are shown in these two frames derived from images of Jupiter's moon Ganymede by NASA's Galileo and Voyager spacecraft. The left frame (a) is a mosaic of images taken by Galileo with a resolution of 140 meters (460 feet) per pixel. Erech Sulcus is the band of grooved terrain extending north-south between two blocks of older, dark terrain. It is about 75 meters (about 250 feet) wide. A portion of Sippar Sulcus, nearly perpendicular to Erech Sulcus, lies to the south. A caldera to the right is truncated by a narrow lane of Sippar's smooth terrain. The right frame (b) shows a digital elevation model of the three-dimensional shape of the same scene. Relative elevation values, estimated from comparison of Galileo and lower-resolution Voyager images, have been color-coded and merged with the image mosaic. The bright terrain of Sippar Sulcus lies at a lower elevation than the dark terrain bordering it. These images were prepared by the Lunar and Planetary Institute, Houston, and included in a report by Dr. Paul Schenk et al. in the March 1, 2001, edition of the journal Nature. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the Galileo and Voyager missions for NASA's Office of Space Science, Washington, D.C. Images and data received from Galileo are posted on the Galileo mission home page at http://www.jpl.nasa.gov/galileo. Background information and educational context for the images can be found at http://www.jpl.nasa.gov/galileo/sepo . |
| Date |
03.13.2001 |
|
Surface of Enceladus
| Title |
Surface of Enceladus |
| Description |
The surface of Enceladus is seen in this closeup view obtained Aug. 25, when Voyager 2 was 112,000 kilometers (69,500 miles) from this satellite of Saturn. This view, in which Enceladus north pole is toward the bottom right, shows the moon to bear a striking resemblance of Ganymede, the largest Galilean satellite of Jupiter. Moderately cratered areas have been transected by strips of younger grooved terrain. This more recently formed terrain--the light cratering says it must be relatively young--has consumed portions of craters such as those near the bottom center of this picture. This suggests that Enceladus has experienced internal melting even though it is only about 490 km. (300 mi.) in diameter. The grooves and linear features indicate that the satellite has been subjected to considerable crustal deformation as a result of this internal melting. The largest crater visible here is about 35 km. (20 mi.) across. The Voyager project is managed for NASA by the Jet Propulsion Laboratory, Pasadena, Calif. |
| Date |
08.26.1981 |
|
Ganymede Galileo Regio High
…
| Title |
Ganymede Galileo Regio High Resolution Mosaic Shown in Context |
| Description |
Ancient impact craters shown in this image of Jupiter's moon Ganymede taken by NASA's Galileo spacecraft testify to the great age of the terrain, dating back several billion years. At the margin at the left, half of a 19-kilometer-diameter (12-mile) crater is visible. The dark and bright lines running from lower right to upper left and from top to bottom are deep furrows in the ancient crust of dirty water ice. The origin of the dark material is unknown, but it may be accumulated dark fragments from many meteorites that hit Ganymede. In this view, north is to the top, and the sun illuminates the surface from the lower left about 58 degrees above the horizon. The area shown is part of Ganymede's Galileo Regio region at latitude 18 degrees north, longitude 147 degrees west, it is about 46 by 64 kilometers (29 by 38 miles) in extent. Resolution is about 80 meters (262 feet) per pixel. The image was taken June 27 at a range of 7.563 kilometers (4,700 miles). The Jet Propulsion Laboratory manages the Galileo mission for NASA's Office of Space Science, Washington, DC. This image and other images and data received from Galileo are posted on the World Wide Web Galileo mission home page at http://galileo.jpl.nasa.gov. Background information and educational context for the images can be found at http:// www.jpl.nasa.gov/galileo/sepo. |
| Date |
02.27.1997 |
|
Ganymede Groove Lanes
| Title |
Ganymede Groove Lanes |
| Description |
An ancient dark terrain surface is cut by orthogonal sets of fractures on Jupiter's moon Ganymede. Subdued pits visible on unbroken blocks are the remnants of impact craters which have degraded with time. Across the top of the image, a line of these subdued pits may have been a chain of craters which are now cut apart by the northwest to southeast trending fractures. North is to the top. Younger craters appear as bright circles. The fractures in this image range from less than 100 meters (328 feet) to over a kilometer (0.62 miles) in width. They display bright walls where cleaner ice may be exposed, and deposits of dark material fill their floors. This 27 by 22 kilometer (17 by 14 mile) image of northern Marius Regio was obtained on September 6, 1996 by NASA's Galileo spacecraft at a resolution of 85 meters (278 feet) per picture element (pixel). The Jet Propulsion Laboratory, Pasadena, CA manages the Galileo mission for NASA's Office of Space Science, Washington, DC. JPL is an operating division of California Institute of Technology (Caltech). This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo mission home page at URL http://galileo.jpl.nasa.gov. Background information and educational context for the images can be found at URL http://www.jpl.nasa.gov/galileo/sepo |
| Date |
03.26.1997 |
|
Ganymede Uruk Sulcus High Re
…
| Title |
Ganymede Uruk Sulcus High Resolution Mosaic Shown in Context |
| Description |
A mosaic of four Galileo high-resolution images of the Uruk Sulcus region of Jupiter's moon Ganymede (Latitude 11 N, Longitude: 170 W) is shown within the context of an image of the region taken by Voyager 2 in 1979, which in turn is shown within the context of a full-disk image of Ganymede. North is to the top of the picture, and the sun illuminates the surface from the lower left, nearly overhead. The area shown is about 120 by 110 kilometers (75 by 68 miles) in extent and the smallest features that can be discerned are 74 meters (243 feet) in size in the Galileo images and 1.3 kilometers (0.8 miles) in the Voyager data. The higher resolution Galileo images unveil the details of parallel ridges and troughs that are principal features in the brighter regions of Ganymede. High photometric activity (large light contrast at high spatial frequencies) of this ice-rich surface was such that the Galileo camera's hardware data compressor was pushed into truncating lines. The north-south running gap between the left and right halves of the mosaic is a result of line truncation from the normal 800 samples per line to about 540. The images were taken on 27 June, 1996 Universal Time at a range of 7,448 kilometers (4,628 miles) through the clear filter of the Galileo spacecraft's imaging system. Launched in October 1989, Galileo entered orbit around Jupiter on December 7, 1995. The spacecraft's mission is to conduct detailed studies of the giant planet, its largest moons and the Jovian magnetic environment. The Jet Propulsion Laboratory manages the Galileo mission for NASA's Office of Space Science, Washington, DC. This image and other images and data received from Galileo are posted on the World Wide Web Galileo mission home page at http://galileo.jpl.nasa.gov. Background information and educational context for the images can be found at http://www.jpl.nasa.gov/galileo/sepo. |
| Date |
02.26.1997 |
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