Browse All : Galileo Orbiter of California

Global Callisto in Color

PIA03456

Jupiter

Solid-State Imaging

Title	Global Callisto in Color
Original Caption Released with Image	Bright scars on a darker surface testify to a long history of impacts on Jupiter's moon Callisto in this image of Callisto from NASA's Galileo spacecraft. The picture, taken in May 2001, is the only complete global color image of Callisto obtained by Galileo, which has been orbiting Jupiter since December 1995. Of Jupiter's four largest moons, Callisto orbits farthest from the giant planet. Callisto's surface is uniformly cratered but is not uniform in color or brightness. Scientists believe the brighter areas are mainly ice and the darker areas are highly eroded, ice-poor material. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the Galileo mission for NASA's Office of Space Science, Washington, D.C. Additional information about the spacecraft and its discoveries is available on the Galileo home page at http://galileo.jpl.nasa.gov [ http://galileo.jpl.nasa.gov ].

Jupiter's Main Ring/Ring Hal …

PIA00701

Jupiter

Solid-State Imaging

Title	Jupiter's Main Ring/Ring Halo
Original Caption Released with Image	A mosaic of four images taken through the clear filter (610 nanometers) of the solid state imaging (CCD) system aboard NASA's Galileo spacecraft on November 8, 1996, at a resolution of approximately 46 kilometers (28.5 miles) per picture element (pixel) along Jupiter's rings. Because the spacecraft was only about 0.5 degrees above the ring plane, the image is highly foreshortened in the vertical direction. The images were obtained when Galileo was in Jupiter's shadow, peering back toward the Sun, the ring was approximately 2.3 million kilometers (1.4 million miles) away. The arc on the far right of the image is produced when sunlight is scattered by small particles comprising Jupiter's upper atmospheric haze. The ring also efficiently scatters light, indicating that much of its brightness is due to particles that are microns or less in diameter. Such small particles are believed to have human-scale lifetimes, i.e., very brief compared to the solar system's age. Jupiter's ring system is composed of three parts - - a flat main ring, a lenticular halo interior to the main ring, and the gossamer ring, outside the main ring. The near and far arms of Jupiter's main ring extend horizontally across the mosaic, joining together at the ring's ansa, on the figure's far left side. The near arm of the ring appears to be abruptly truncated close to the planet, at the point where it passes into Jupiter's shadow. Some radial structure is barely visible across the ring's ansa (top image). A faint mist of particles can be seen above and below the main rings. This vertically extended "halo" is unusual in planetary rings, and is probably caused by electromagnetic forces pushing the smallest grains out of the ring plane. Because of shadowing, the halo is not visible close to Jupiter in the lower right part of the mosaic. To accentuate faint features in the bottom image of the ring halo, different brightnesses are shown through color. Brightest features are white or yellow and the faintest are purple. Jupiter's main ring is a thin strand of material encircling the planet. The diffuse innermost boundary begins at approximately 123,000 kilometers (76,429 miles). The main ring's outer radius is found to be at 128,940 kilometers (80,119 miles) +/-50 kilometers (31 miles), slightly less than the Voyager value of 129,130 kilometers (80,237 miles) +/-100 kilometers (62 miles), but very close to the orbit of the satellite Adrastea (128,980 kilometers or 80,144 miles). The main ring exhibits a marked drop in brightness at 127,849 kilometers (79,441 miles) +/-50 kilometers (31 miles), lying almost atop the orbit of the Jovian moon Metis at 127,978 kilometers (79,521 miles). Satellites seem to affect the structure of even tenuous rings like those found at Jupiter. The Jet Propulsion Laboratory, Pasadena, CA manages the Galileo mission for NASA's Office of Space Science, Washington, DC. JPL is an operating division of California Institute of Technology (Caltech). This image, and other images and data received from Galileo are posted on the World Wide Web, on the Galileo mission home page at URL http://galileo.jpl.nasa.gov. Background information and educational context for the images can be found at URL http://www.jpl.nasa.gov/galileo/sepo

Har Crater on Callisto

PIA01054

Jupiter

Solid-State Imaging

Title	Har Crater on Callisto
Original Caption Released with Image	This image shows a heavily cratered region near Callisto's equator. It was taken by the Galileo spacecraft Solid State Imaging (CCD) system on its ninth orbit around Jupiter. North is to the top of the image. The 50 kilometer (30 mile) double ring crater in the center of the image is named Har. Har displays an unusual rounded mound on its floor. The origin of the mound is unclear but probably involves uplift of ice-rich materials from below, either as a "rebound" immediately following the impact that formed the crater or as a later process. Har is older than the prominent 20 kilometer (12 mile) crater superposed on its western rim. The large crater partially visible in the northeast corner of the image is called Tindr. Chains of secondary craters (craters formed from the impact of materials thrown out of the main crater during an impact) originating from Tindr crosscut the eastern rim of Har. The image, centered at 3.3 degrees south latitude and 357.9 degrees west longitude, covers an area of 120 kilometers by 115 kilometers (75 miles by 70 miles). The sun illuminates the scene from the west (left). The smallest distinguishable features in the image are about 294 meters (973 feet) across. This image was obtained on June 25, 1997, when Galileo was 14,080 kilometers (8,590 miles) from Callisto. The Jet Propulsion Laboratory, Pasadena, CA manages the Galileo mission for NASA's Office of Space Science, Washington, DC. JPL is an operating division of California Institute of Technology (Caltech). This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo mission home page at URL http://galileo.jpl.nasa.gov.

Callisto's Southern Hemisphere as Viewed by NIMS & SSI

Callisto's Southern Hemisphe …

PIA01079

Jupiter

Near Infrared Mapping Spectr …

Title	Callisto's Southern Hemisphere as Viewed by NIMS & SSI
Original Caption Released with Image	Callisto's southern hemisphere was "imaged" by both the Near Infrared Mapping Spectrometer (NIMS) and the Solid State Imaging (SSI) instrument during Galileo's eighth orbit of Jupiter. The data from the two instruments has been mosaiced to produce this unique view. Related releases and detailed captions are available for theNIMS [ http://photojournal.jpl.nasa.gov/catalog/PIA01078 ] andSSI [ http://photojournal.jpl.nasa.gov/catalog/PIA01077 ] products. 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://www.jpl.nasa.gov/ galileo.

Callisto's Southern Hemisphe …

PIA01078

Jupiter

Near Infrared Mapping Spectr …

Title	Callisto's Southern Hemisphere
Original Caption Released with Image	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.

Landslides on Callisto

PIA01095

Jupiter

Solid-State Imaging

Title	Landslides on Callisto
Original Caption Released with Image	Recent Galileo images of the surface of Jupiter's moon Callisto have revealed large landslide deposits within two large impact craters seen in the right side of this image. The two landslides are about 3 to 3.5 kilometers (1.8 to 2.1 miles) in length. They occurred when material from the crater wall failed under the influence of gravity, perhaps aided by seismic disturbances from nearby impacts. These deposits are interesting because they traveled several kilometers from the crater wall in the absence of an atmosphere or other fluids which might have lubricated the flow. This could indicate that the surface material on Callisto is very fine-grained, and perhaps is being "fluffed" by electrostatic forces which allowed the landslide debris to flow extended distances in the absence of an atmosphere. This image was acquired on September 16th, 1997 by the Solid State Imaging (CCD) system on NASA's Galileo spacecraft, during the spacecraft's tenth orbit around Jupiter. North is to the top of the image, with the sun illuminating the scene from the right. The center of this image is located near 25.3 degrees north latitude, 141.3 degrees west longitude. The image, which is 55 kilometers (33 miles) by 44 kilometers (26 miles) across, was acquired at a resolution of 100 meters per picture element. The Jet Propulsion Laboratory, Pasadena, CA manages the Galileo mission for NASA's Office of Space Science, Washington, DC. JPL is an operating division of California Institute of Technology (Caltech). This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo mission home page at URL http://galileo.jpl.nasa.gov.

Io Eclipse/Volcanic Eruption

PIA00704

Sol (our sun)

Solid-State Imaging

Title	Io Eclipse/Volcanic Eruption
Original Caption Released with Image	This image was acquired while Io was in eclipse (in Jupiter's shadow) during Galileo's eighth orbit, and reveals several dynamic processes. The most intense features are red, while glows of lesser intensity are yellow or green, and very faint glows appear blue in this color-coded image. The small red or yellow spots mark the sites of high-temperature magma erupting onto the surface in lava flows or lava lakes. This image reveals a field of bright spots near Io's sub-Jupiter point (right-hand side of image). The sub-Jupiter hemisphere always faces Jupiter just as the Moon's nearside always faces Earth. There are extended diffuse glows on the equatorial limbs or edges of the planet (right and left sides). The glow on the left is over the active volcanic plume Prometheus, but whereas Prometheus appears to be 75 kilometers (46.6 miles) high in reflected light, here the diffuse glow extends about 800 kilometers (497 miles) from Io's limb. This extended glow indicates that gas or small particles reach much greater heights than the dense inner plume. The diffuse glow on the right side reaches a height of 400 kilometers (249 miles), and includes a prominence with a plume-like shape. However, no volcanic plume has been seen at this location in reflected light. This type of observation is revealing the relationships between Io's volcanism, atmosphere and exosphere. Taken on May 6, 1997, north is toward the top. The image was taken with the clear filter of the solid state imaging (CCD) system on NASA's Galileo spacecraft at a range of 1.8 million kilometers (1.1 million miles). The Jet Propulsion Laboratory, Pasadena, CA manages the Galileo mission for NASA's Office of Space Science, Washington, DC. JPL is an operating division of California Institute of Technology (Caltech). This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo mission home page at URL http://galileo.jpl.nasa.gov. Background information and educational context for the images can be found at URL http://www.jpl.nasa.gov/galileo/sepo

View of Callisto at Increasing Resolutions

View of Callisto at Increasi …

PIA01297

Jupiter

Solid-State Imaging

Title	View of Callisto at Increasing Resolutions
Original Caption Released with Image	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, These four views of Jupiter's second largest moon, Callisto, highlight how increasing resolutions enable interpretation of the surface. In the global view (top left) the surface is seen to have many small bright spots, while the regional view (top right) reveals the spots to be the larger craters. The local view (bottom right) not only brings out smaller craters and detailed structure of larger craters, but also shows a smooth dark layer of material that appears to cover much of the surface. The close-up frame (bottom left) presents a surprising smoothness in this highest resolution (30 meters per picture element) view of Callisto's surface. North is to the top of these frames which were taken by the Solid State Imaging (SSI) system on NASA's Galileo spacecraft between November 1996 and November 1997. Even higher resolution images (better than 20 meters per picture element) of Callisto will be taken on June 30, 1999 during the 21st orbit of the spacecraft around Jupiter. The top left frame is scaled to 10 kilometers (km) per picture element (pixel) and covers an area about 4400 by 2500 km. The moon Callisto, which has a diameter of 4806 km, appears to be peppered with many bright spots. Images at this resolution of other cratered moons in the Solar System indicate that the bright spots could be impact craters. The ring structure of Valhalla, the largest impact structure on Callisto, is visible in the center of the frame. This color view combines images obtained in November 1997 taken through the green, violet, and 1 micrometer filters of the SSI system. The top right frame is ten times higher resolution (about 1 km per pixel) and covers an area approximately 440 by 250 km. Craters, which are clearly recognizable, appear to be the dominant landform on Callisto. The crater rims appear bright, while the adjacent area and the crater interiors are dark. This resolution is comparable to the best data available from the 1979 flyby's of NASA's two Voyager spacecraft, it reflects the understanding of Callisto prior to new data from Galileo. This Galileo image was taken in November 1996. The resolution of the bottom right image is again ten times better (100 meters per pixel) and covering an area of about 44 by 25 km. This resolution reveals that some crater rims are not complete rings, but are composed of bright isolated segments. Steep slopes near crater rims reveal dark material that appears to have slid down to reveal bright material. The thickness of the dark layer could be tens of meters. The image was taken in June 1997. The bottom left image at about 29 meters per pixel is the highest resolution available for Callisto. It covers an area about 4.4 by 2.5 km and is somewhat oblique. Craters are visible but no longer dominate the surface. The image was taken in November 1996. 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

Ancient Impact Basin on Euro …

PIA00702

Jupiter

Solid-State Imaging

Title	Ancient Impact Basin on Europa
Original Caption Released with Image	This feature on Europa was seen as a dark, diffuse circular patch on a previous Galileo global image of Europa's leading hemisphere on April 3, 1997. The "bulls-eye" pattern appears to be a 140- kilometer (86-mile) wide impact scar (about the size of the island of Hawaii) which formed as the surface fractured minutes after a mountain-sized asteroid or comet slammed into the satellite. This approximately 214-kilometer (132-mile) wide picture is the product of three images which have been processed in false color to enhance shapes and compositions. North is toward the top of this picture, which is illuminated from sunlight coming from the west. This color composite reveals a sequence of events which have modified the surface of Europa. The earliest event was the impact which formed the Tyre structure at 34 degrees north latitude and 146.5 degrees west longitude. The impact was followed by the formation of the reddish lines superposed on Tyre. The red color designates areas that are probably a dirty water ice mixture. The fine blue-green lines crossing the region from west to east appear to be ridges which formed after the crater. The images were taken on April 4, 1997, at a resolution of 595 meters (1950 feet) per picture element and a range of 29,000 kilometers (17,900 miles). The images were taken by Galileo's solid state imaging (CCD) system. 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

Global Color Variations on C …

PIA01298

Jupiter

Solid-State Imaging

Title	Global Color Variations on Callisto
Original Caption Released with Image	Jupiter's icy moon Callisto is shown in approximate natural color (left) and in false color to enhance subtle color variations (right). This image of Callisto's Jupiter-facing hemisphere shows the ancient, multi-ring impact structure Valhalla just above the center of the image. Valhalla, possibly created by a large asteroid or comet which impacted Callisto, is the largest surface feature on this icy moon. Valhalla consists of a bright inner region, about 600 kilometers (360 miles) in diameter surrounded by concentric rings 3000 to 4000 kilometers (1800-2500 miles) in diameter. The bright central plains were possibly created by the excavation and ejection of "cleaner" ice from beneath the surface, with a fluid-like mass (impact melt) filling the crater bowl after impact. The concentric rings are fractures in the crust resulting from the impact. The false color in the right image shows new information, including ejecta from relatively recent craters, which are often not apparent in the natural color image. The color also reveals a gradual variation across the moon's hemisphere, perhaps due to implantation of materials onto the surface from space. These color images were obtained with the 1 micrometer (infrared), green, and violet filters of the Solid State Imaging (SSI) system on NASA's Galileo spacecraft. The false color is created from ratios of infrared/violet and its inverse (violet/infrared) which are then combined so the infrared/violet, green, and violet/infrared are assigned to red, green, and blue in a composite product. North is to the top of the picture and 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, centered at 0.5 degrees south latitude and 56.3 degrees longitude, covers an area about 4800 by 4800 kilometers. The resolution is 14 kilometers per picture element. The images were taken on November 5, 1997 at a range of 68,400 kilometers (41,000 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. 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

New Territory West of the Great Red Spot

New Territory West of the Gr …

PIA00719

Sol (our sun)

Solid-State Imaging

Title	New Territory West of the Great Red Spot
Original Caption Released with Image	Turbulent region west of Jupiter's Great Red Spot. This four image mosaic shows the Great Red Spot on Jupiter's eastern edge or limb. The images have been re-projected onto a square grid of latitude and longitude lines. The upper left tile of the four-tile mosaic is in green (559 nm) light, while the rest are in violet (415 nm). Variations in brightness between the images are due to the different filters and exposure times used in this observation. The region west of the Great Red Spot is characterized by large, turbulent structures that rotate clockwise, in the opposite sense of the Great Red Spot. The centers of some of these structures are extremely bright, and may be giant (2000 km) clusters of cumulus clouds. Regions of large-scale turbulence are rare in Jupiter's otherwise very stable and organized atmosphere. North is to the top. Each pixel subtends a square about 29.5 kilometers on a side. The images were obtained on June 26, 1996 by the Solid State Imaging system on board NASA's Galileo spacecraft. The Jet Propulsion Laboratory, Pasadena, CA manages the mission for NASA'is Office of Space Science, Washington, DC. This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo mission home page at URL http://galileo.jpl.nasa.gov. Background information and educational context for the images can be found at URL http://www.jpl.nasa.gov/galileo/sepo.

Time Series of the Great Red Spot (near-infrared filter)

Time Series of the Great Red …

PIA00720

Sol (our sun)

Solid-State Imaging

Title	Time Series of the Great Red Spot (near-infrared filter)
Original Caption Released with Image	Time Evolution of Jupiter's Great Red Spot in the 757 nm (near-infrared) filter of the Galileo Imaging system. These mosaics (6 frames each) were taken nine hours apart and reveal Jupiter's winds through the movements of cloud features. The Great Red Spot is a large atmospheric vortex (20,000 kilometers in its largest diameter) with counter-clockwise winds that reach 150 meters per second near its outer edges. It is embedded between a westward jet to the north and an eastward jet to the south. The central region of the Great Red Spot is relatively quiescent and shows little change over this time period. The direction and velocity of Jupiter's winds are determined by measuring the displacements of cloud features in images such as these. Several competing theories seek to explain the existence and stability of Jovian atmospheric features, including the Great Red Spot. Wind measurements from Galileo images will help distinguish between competing theories. While at first glance the Great Red Spot appears similar to a terrestrial hurricane or mid-latitude storm, its enormous size and the lack of a solid surface on Jupiter complicate such comparisons. North is to the top in both frames. Each pixel subtends a square about 30 kilometers on a side. The images were obtained on June 26th, 1996. The Jet Propulsion Laboratory, Pasadena, CA manages the mission for NASA'is Office of Space Science, Washington, DC. This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo mission home page at URL http://galileo.jpl.nasa.gov. Background information and educational context for the images can be found at URL http://www.jpl.nasa.gov/galileo/sepo.

Jupiter's White Ovals/True and False Color

Jupiter's White Ovals/True a …

PIA00700

Sol (our sun)

Solid-State Imaging

Title	Jupiter's White Ovals/True and False Color
Original Caption Released with Image	Oval cloud systems of this type are often associated with chaotic cyclonic systems such as the balloon-shaped vortex seen here between the well-formed ovals. This system is centered near 30 degrees south latitude relative to the center of the planet and 100 degrees west longitude, and rotates in a clockwise direction about its center. The oval shaped vortices in the upper half of the mosaic are two of the three long-lived white ovals that formed to the south of the Great Red Spot in the 1930's and, like the Great Red Spot, rotate in a counterclockwise sense. The east-to-west dimension of the left-most white oval is 9,000 kilometers (5,592 miles) across. For comparison, the diameter of Earth is 12,756 kilometers, or 7,928 miles. The white ovals drift in longitude relative to one another and are presently restricting the cyclonic structure. To the south, the smaller oval and its accompanying cyclonic system are moving eastward at about 0.4 degrees per day relative to the larger ovals. The interaction between these two cyclonic storm systems is producing high, thick cumulus-like clouds in the southern part of the more northerly trapped system. The top mosaic combines the violet (410 nanometers) and near infrared continuum (756 nanometers) filter images to create a mosaic similar to how Jupiter would appear to human eyes. Differences in coloration are due to the composition and abundance of trace chemicals in Jupiter's atmosphere. The lower mosaic uses the Galileo imaging camera's three near-infrared wavelengths (756 nanometers, 727 nanometers, and 889 nanometers displayed in red, green, and blue) to show variations in cloud height and thickness. Light blue clouds are high and thin, reddish clouds are deep, and white clouds are high and thick. The clouds and haze over the white ovals are high, extending into Jupiter's stratosphere. There is a lack of high haze over the cyclonic feature. Dark purple most likely represents a high haze overlying a clear deep atmosphere. Galileo is the first spacecraft to distinguish cloud layers on Jupiter. North is at the top of these mosaics. The smallest resolved features are tens of kilometers in size. These images were taken on February 19, 1997, at a range of 1.1 million kilometers (683,507 miles) by the solid state imaging (CCD) system aboard NASA's Galileo spacecraft. 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

Opposite Side of Callisto from Valhalla Impact

Opposite Side of Callisto fr …

PIA02593

Jupiter

Solid-State Imaging

Title	Opposite Side of Callisto from Valhalla Impact
Original Caption Released with Image	The heavily cratered portion of the surface of Jupiter's moon Callisto, seen in this image recorded by NASA's Galileo spacecraft, resembles most of Callisto that's been seen in high resolution. This adds evidence to a theory that Callisto may hold an underground ocean. The area in the image is the opposite point, or antipode, of Callisto's Valhalla impact basin. The antipode of any point on a sphere is the opposite point on a line through the center of the sphere. Antipodes of major impact sites on some other worlds similar in size to Callisto, such as Mercury and Earth's moon, show a grooved and hilly terrain attributed to seismic shocks focusing on those points from the distant impacts. The antipode of Mercury's Caloris impact site [ http://photojournal.jpl.nasa.gov/catalog/PIA02445 ] is one example. When Galileo flew near Callisto on May 25, 2001, scientists sought an image to check the Valhalla antipode for similar signs of disruption. Computer modeling has suggested that if Callisto had a water layer in its interior, that layer would have dispersed the seismic shock waves from the ancient Valhalla impact. The absence of grooved and hilly terrain at the Valhalla antipode is consistent with that possibility. Magnetic-field measurements have previously suggested that Callisto has a layer of liquid water deep below its surface. This image, taken from a distance of 32,000 kilometers (about 20,000 miles) shows details at the Valhalla antipode down to a size of about 330 meters (about 1,250 feet)across. Callisto is the outermost of Jupiter's four large moons. Its surface of ice and rock is the most heavily cratered of any moon in the solar system. For a view of this image in context click here. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the Galileo mission for NASA's Office of Space Science, Washington, D.C. Additional information about the spacecraft and its discoveries is available on the Galileo home page at http://galileo.jpl.nasa.gov [ http://galileo.jpl.nasa.gov ].

Opposite Side of Callisto fr …

PIA02593

Jupiter

Solid-State Imaging

Title	Opposite Side of Callisto from Valhalla Impact
Original Caption Released with Image	The heavily cratered portion of the surface of Jupiter's moon Callisto, seen in this image recorded by NASA's Galileo spacecraft, resembles most of Callisto that's been seen in high resolution. This adds evidence to a theory that Callisto may hold an underground ocean. The area in the image is the opposite point, or antipode, of Callisto's Valhalla impact basin. The antipode of any point on a sphere is the opposite point on a line through the center of the sphere. Antipodes of major impact sites on some other worlds similar in size to Callisto, such as Mercury and Earth's moon, show a grooved and hilly terrain attributed to seismic shocks focusing on those points from the distant impacts. The antipode of Mercury's Caloris impact site [ http://photojournal.jpl.nasa.gov/catalog/PIA02445 ] is one example. When Galileo flew near Callisto on May 25, 2001, scientists sought an image to check the Valhalla antipode for similar signs of disruption. Computer modeling has suggested that if Callisto had a water layer in its interior, that layer would have dispersed the seismic shock waves from the ancient Valhalla impact. The absence of grooved and hilly terrain at the Valhalla antipode is consistent with that possibility. Magnetic-field measurements have previously suggested that Callisto has a layer of liquid water deep below its surface. This image, taken from a distance of 32,000 kilometers (about 20,000 miles) shows details at the Valhalla antipode down to a size of about 330 meters (about 1,250 feet)across. Callisto is the outermost of Jupiter's four large moons. Its surface of ice and rock is the most heavily cratered of any moon in the solar system. For a view of this image in context click here. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the Galileo mission for NASA's Office of Space Science, Washington, D.C. Additional information about the spacecraft and its discoveries is available on the Galileo home page at http://galileo.jpl.nasa.gov [ http://galileo.jpl.nasa.gov ].

Active Volcanic Plumes on Io

PIA00703

Jupiter

Solid-State Imaging

Title	Active Volcanic Plumes on Io
Original Caption Released with Image	This color image, acquired during Galileo's ninth orbit around Jupiter, shows two volcanic plumes on Io. One plume was captured on the bright limb or edge of the moon (see inset at upper right), erupting over a caldera (volcanic depression) named Pillan Patera after a South American god of thunder, fire and volcanoes. The plume seen by Galileo is 140 kilometers (86 miles) high and was also detected by the Hubble Space Telescope. The Galileo spacecraft will pass almost directly over Pillan Patera in 1999 at a range of only 600 kilometers (373 miles). The second plume, seen near the terminator (boundary between day and night), is called Prometheus after the Greek fire god (see inset at lower right). The shadow of the 75-kilometer (45- mile) high airborne plume can be seen extending to the right of the eruption vent. The vent is near the center of the bright and dark rings. Plumes on Io have a blue color, so the plume shadow is reddish. The Prometheus plume can be seen in every Galileo image with the appropriate geometry, as well as every such Voyager image acquired in 1979. It is possible that this plume has been continuously active for more than 18 years. In contrast, a plume has never been seen at Pillan Patera prior to the recent Galileo and Hubble Space Telescope images. North is toward the top of the picture. The resolution is about 6 kilometers (3.7 miles) per picture element. This composite uses images taken with the green, violet and near infrared filters of the solid state imaging (CCD) system on NASA's Galileo spacecraft. The images were obtained on June 28, 1997, at a range of more than 600,000 kilometers (372,000 miles). The Jet Propulsion Laboratory, Pasadena, CA manages the Galileo mission for NASA's Office of Space Science, Washington, DC. JPL is an operating division of California Institute of Technology (Caltech). This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo mission home page at URL http://galileo.jpl.nasa.gov. Background information and educational context for the images can be found at URL http://www.jpl.nasa.gov/galileo/sepo

Callisto Close-up with Jagge …

PIA03455

Jupiter

Solid-State Imaging

Title	Callisto Close-up with Jagged Hills
Original Caption Released with Image	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 at http://galileo.jpl.nasa.gov [ http://galileo.jpl.nasa.gov ].

Topography of Io (color)

PIA00740

Jupiter

Solid-State Imaging

Title	Topography of Io (color)
Original Caption Released with Image	The images used to create this color composite of Io were acquired by Galileo during its ninth orbit (C9) of Jupiter and are part of a sequence of images designed to map the topography or relief on Io and to monitor changes in the surface color due to volcanic activity. Obtaining images at low illumination angles is like taking a picture from a high altitude around sunrise or sunset. Such lighting conditions emphasize the topography of the volcanic satellite. Several mountains up to a few miles high can be seen in this view, especially near the upper right. Some of these mountains appear to be tilted crustal blocks. Most of the dark spots correspond to active volcanic centers. North is to the top of the picture which merges images obtained with the clear, red, green, and violet filters of the solid state imaging (CCD) system on NASA's Galileo spacecraft. . The resolution is 8.3 kilometers per picture element. The image was taken on June 27, 1997 at a range of 817,000 kilometers by the solid state imaging (CCD) system on NASA's Galileo spacecraft. The Jet Propulsion Laboratory, Pasadena, CA manages the Galileo mission for NASA's Office of Space Science, Washington, DC. 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

The Great Red Spot at Four Different Wavelengths

The Great Red Spot at Four D …

PIA00721

Sol (our sun)

Solid-State Imaging

Title	The Great Red Spot at Four Different Wavelengths
Original Caption Released with Image	Comparison of Jupiter's Great Red Spot at four wavelengths. These mosaics (6 frames each) show the appearance of the Great Red Spot in violet light (415 nm, upper left), infrared light (757 nm, upper right), and infrared light within both a weak (732 nm, lower left) and a strong (886 nm, lower right) methane absorption band. The images were taken within minutes of each other. Reflected sunlight at each of these wavelengths penetrates to different depths and is scattered or absorbed by different atmospheric constituents before detection by Galileo. The violet mosaic reveals the relative abundances of chemicals that color Jupiter's atmosphere. The three infrared images respectively probe higher in Jupiter's atmosphere. The highest features, such as the diffuse haze that overlies the Great Red Spot and the small clouds to the northeast of it, are most apparent on the 886 nm mosaic. North is to the top in all frames. Each pixel subtends a square about 30 kilometers on a side. The images were obtained on June 26, 1996 by the Solid State Imaging system on board NASA's Galileo spacecraft. The Jet Propulsion Laboratory, Pasadena, CA manages the mission for NASA'is Office of Space Science, Washington, DC. This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo mission home page at URL http://galileo.jpl.nasa.gov. Background information and educational context for the images can be found at URL http://www.jpl.nasa.gov/galileo/sepo.

Eclipse Images of Io (3 view …

PIA00739

Jupiter

Solid-State Imaging

Title	Eclipse Images of Io (3 views)
Original Caption Released with Image	These three images of Io in eclipse (top) show volcanic hot spots and airglow associated with volcanic plumes and Io's atmosphere. They were acquired by NASA's Galileo spacecraft during three separate orbits of Jupiter when the moon was in Jupiter's shadow. Brightnesses are color-coded from red which displays the highest intensity to dark blue which displays zero intensity (no light). Below them are the corresponding views of Io in reflected sunlight, reprojected from a global mosaic of images obtained during Galileo's first and second orbits of Jupiter. These lit views help to identify the locations of the hot spots seen in the eclipse images. The grid marks are at 15 degree intervals of latitude and longitude. North is to the top. In the eclipse images (top) small red ovals and perhaps some small green areas are due to thermal emission from volcanic hot spots with temperatures hotter than about 700 kelvin (about 1000 degrees Fahrenheit). Diffuse greenish areas seen near the limb or edge of the moon are probably the result of auroral and/or airglow emissions of neutral species of oxygen or sulfur in volcanic plumes and in Io's patchy atmosphere. All images were acquired by the solid state imaging (CCD) system on NASA's Galileo spacecraft. The top left image was obtained during the spacecraft's fourth orbit (E4) on December 17, 1996, the top middle image during the sixth orbit (E6) on February 21, 1997, and the top right image during the first orbit (G1) on June 29th, 1996. The relatively long exposures used to obtain these eclipse images lead to some smearing of the picture elements which reduces the actual resolution. Unsmeared they would have resolutions of 17.6, 9.1, and 10.5 kilometers per picture element respectively (left to right). 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). Concurrent results from Galileo's exploration of Io appear in the October 15th, 1997 issue of Geophysical Research Letters. The papers are: * Temperature and Area Constraints of the South Volund Volcano on Io from the NIMS and SSI Instruments during the Galileo G1 Orbit, by A.G. Davies, A.S. McEwen, R. Lopes-Gautier, L. Keszthelyi, R.W. Carlson and W.D. Smythe. * High-temperature hot spots on Io as seen by the Galileo Solid-State Imaging (SSI) experiment, by A. McEwen, D. Simonelli, D. Senske, K. Klassen, L. Keszthelyi, T. Johnson, P. Geissler, M. Carr, and M. Belton. * Io: Galileo evidence for major variations in regolith properties, by D. Simonelli, J. Veverka, and A. McEwen. 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

Topography and Volcanoes on …

PIA00738

Jupiter

Solid-State Imaging

Title	Topography and Volcanoes on Io (color)
Original Caption Released with Image	The images used to create this enhanced color composite of Io were acquired by NASA's Galileo spacecraft during its seventh orbit (G7) of Jupiter. Low sun angles near the terminator (day-night boundary near the left side of the image) offer lighting conditions which emphasize the topography or relief on the volcanic satellite. The topography appears very flat near the active volcanic centers such as Loki Patera (the large dark horse-shoe shaped feature near the terminator) while a variety of mountains and plateaus exist elsewhere. The big reddish-orange ring in the lower right is formed by material deposited from the eruption of Pele, Io's largest volcanic plume. North is to the top of this picture which merges images obtained with the clear, red, green, and violet filters of the solid state imaging (CCD) system on NASA's Galileo spacecraft. The resolution is 6.1 kilometers per picture element. The images were taken on April 4th, 1997 at a range of 600,000 kilometers. 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). Concurrent results from Galileo's exploration of Io appear in the October 15th, 1997 issue of Geophysical Research Letters. The papers are: * Temperature and Area Constraints of the South Volund Volcano on Io from the NIMS and SSI Instruments during the Galileo G1 Orbit, by A.G. Davies, A.S. McEwen, R. Lopes-Gautier, L. Keszthelyi, R.W. Carlson and W.D. Smythe. * High-temperature hot spots on Io as seen by the Galileo Solid-State Imaging (SSI) experiment, by A. McEwen, D. Simonelli, D. Senske, K. Klassen, L. Keszthelyi, T. Johnson, P. Geissler, M. Carr, and M. Belton. * Io: Galileo evidence for major variations in regolith properties, by D. Simonelli, J. Veverka, and A. McEwen. 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

Changes in Jupiter's Great Red Spot After Four Months

Changes in Jupiter's Great R …

PIA01119

Sol (our sun)

Solid-State Imaging

Title	Changes in Jupiter's Great Red Spot After Four Months
Original Caption Released with Image	Northeast (upper right) quadrant of Jupiter's Great Red Spot in June and November 1996. The top panel shows the region in near-infrared light (732 nanometers) on June 26, 1996. The bottom panel shows the same region at 757 nanometers on November 5, 1996. Both images show features in Jupiter's main visible cloud deck. A westward (to the left) jet is deflected northward by the Great Red Spot in this region. Cloud features, possibly including thunderstorms, were actively changing during the June encounter. The deflection around the Red Spot appears to be less during the November encounter. Small thunderstorm-like clouds are once again present. The bottom image was taken with the high resolution mode of the camera that allows features twice as small to be detected. North is at the top. The images are approximately 6000 kilometers from north to south and 15,000 kilometers from east to west. They are centered at 14 degrees latitude and 314 and 353 degrees west longitude, respectively. The smallest resolved features are tens of kilometers in size. These images were taken by the Solid State Imaging system aboard NASA's Galileo spacecraft. 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

Regional Mosaic of Chaos and Gray Band on Europa

Regional Mosaic of Chaos and …

PIA01125

Jupiter

Solid-State Imaging

Title	Regional Mosaic of Chaos and Gray Band on Europa
Original Caption Released with Image	This mosaic of part of Jupiter's moon, Europa, shows a region that is characterized by mottled (dark and splotchy) terrain. The images in this mosaic were obtained by Solid State Imaging (CCD) system on NASA's Galileo spacecraft during its eleventh orbit around Jupiter. North is to the top of the image, and the sun illuminates the scene from the right. Prior to obtaining these pictures, the age and origin of mottled terrain were not known. As seen here, the mottled appearance results from areas of the bright, icy crust that have been broken apart (known as "chaos" terrain), exposing a darker underlying material. This terrain is typified by the area in the upper right-hand part of the image. The mottled terrain represents some of the most recent geologic activity on Europa. Also shown in this image is a smooth, gray band (lower part of image) representing a zone where the Europan crust has been fractured, separated, and filled in with material derived from the interior. The chaos terrain and the gray band show that this satellite has been subjected to intense geological deformation. The mosaic, centered at 2.9 degrees south latitude and 234.1 degrees west longitude, covers an area of 365 kilometers by 335 kilometers (225 miles by 210 miles). The smallest distinguishable features in the image are about 460 meters (1500 feet) across. These images were obtained on November 6, 1997, when the Galileo spacecraft was approximately 21,700 kilometers (13,237 miles) from Europa. The Jet Propulsion Laboratory, Pasadena, CA manages the mission for NASA's Office of Space Science, Washington, DC. JPL is a division of California Institute of Technology. This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo home page at URL http://galileo.jpl.nasa.gov. Background information and educational context can be found at URL http://www.jpl.nasa.gov/galileo/sepo

High Resolution Mosaic of Ridges, Plains, and Mountains on Europa

High Resolution Mosaic of Ri …

PIA01126

Jupiter

Solid-State Imaging

Title	High Resolution Mosaic of Ridges, Plains, and Mountains on Europa
Original Caption Released with Image	This mosaic shows some of the highest resolution images obtained by the Solid State Imaging (SSI) system on NASA's Galileo spacecraft during its eleventh orbit around Jupiter. North is to the top of the image. The sun illuminates the scene from the left, showing hundreds of ridges that cut across each other, indicating multiple episodes of ridge formation either by volcanic or tectonic activity within the ice. Also visible in the image are numerous isolated mountains or "massifs". The highest of these, located in the upper right corner and lower center of the mosaic, are approximately 500 meters (1,640 feet) high. Irregularly shaped areas where the ice surface appears to be lower than the surrounding plains (e.g., in the left-center and lower left corner of the mosaic) may be related to the "chaos" areas of iceberg-like features seen in earlier SSI images of Europa. The mosaic, centered at 35.4 degrees north latitude and 86.8 degrees west longitude, covers an area of 108 kilometers by 90 kilometers (66 miles by 55 miles). The smallest distinguishable features in the image are about 68 meters (223 feet) across. These images were obtained on November 6, 1997, when the Galileo spacecraft was approximately 3,250 kilometers (1,983 miles) from Europa. The Jet Propulsion Laboratory, Pasadena, CA manages the mission for NASA's Office of Space Science, Washington, DC. JPL is a division of California Institute of Technology. This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo 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

Jupiter's Belt-Zone Boundary in Near-Infrared and Violet Light

Jupiter's Belt-Zone Boundary …

PIA01115

Sol (our sun)

Solid-State Imaging

Title	Jupiter's Belt-Zone Boundary in Near-Infrared and Violet Light
Original Caption Released with Image	Mosaics of a belt-zone boundary near Jupiter's equator in violet (top panel) and near-infrared (bottom panel) light. The four images that make up each of these mosaics were taken within a few minutes of each other. Sunlight at 757 nanometers (near-infrared) penetrates deep into Jupiter's troposphere before being absorbed or scattered by clouds to the Galileo spacecraft. This wavelength reveals the features of the lower visible cloud deck. Sunlight at 415 nanometers (violet) is a scattered or absorbed to varying degrees in different parts of Jupiter's atmosphere depending on the types and concentrations of cloud particles and chemicals that color Jupiter's atmosphere. The near-infrared mosaic primarily shows cloud features. The violet mosaic has three distinct regions: it is brightest at the latitude of the jet (horizontally across the center of the mosaic), moderately bright north of the jet, and dark and patchy south of the jet. North is at the top. The mosaic covers latitudes -13 to +3 degrees and is centered at longitude 282 degrees West. The smallest resolved features are tens of kilometers in size. These images were taken on November 5th, 1996, at a range of 1.2 million kilometers by the Solid State Imaging system aboard NASA's Galileo spacecraft. 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

Europa - Ice Rafting View

PIA01127

Jupiter

Solid-State Imaging

Title	Europa - Ice Rafting View
Original Caption Released with Image	View of a small region of the thin, disrupted, ice crust in the Conamara region of Jupiter's moon Europa showing the interplay of surface color with ice structures. The white and blue colors outline areas that have been blanketed by a fine dust of ice particles ejected at the time of formation of the large (26 kilometer in diameter) crater Pwyll [ http://photojournal.jpl.nasa.gov/catalog/PIA01211 ] some 1000 kilometers to the south. A few small craters of less than 500 meters or 547 yards in diameter can be seen associated with these regions. These were probably formed, at the same time as the blanketing occurred, by large, intact, blocks of ice thrown up in the impact explosion that formed Pwyll. The unblanketed surface has a reddish brown color that has been painted by mineral contaminants carried and spread by water vapor released from below the crust when it was disrupted. The original color of the icy surface was probably a deep blue color seen in large areas elsewhere on the moon. The colors in this picture have been enhanced for visibility. North is to the top of the picture and the sun illuminates the surface from the right. The image, centered at 9 degrees north latitude and 274 degrees west longitude, covers an area approximately 70 by 30 kilometers (44 by 19 miles), and combines data taken by the Solid State Imaging (CCD) system on NASA's Galileo spacecraft during three of its orbits through the Jovian system. Low resolution color (violet, green, and infrared) data acquired in September 1996, were combined with medium resolution images from December 1996, to produce synthetic color images. These were then combined with a high resolution mosaic of images [ http://photojournal.jpl.nasa.gov/catalog/PIA00591 ] acquired on February 20th, 1997 at a resolution of 54 meters (59 yards) per picture element and at a range of 5340 kilometers (3320 miles). The Jet Propulsion Laboratory, Pasadena, CA manages the mission for NASA's Office of Space Science, Washington, DC. JPL is a 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

Using Methane Absorption to Probe Jupiter's Atmosphere

Using Methane Absorption to …

PIA01114

Sol (our sun)

Solid-State Imaging

Title	Using Methane Absorption to Probe Jupiter's Atmosphere
Original Caption Released with Image	Mosaics of a belt-zone boundary near Jupiter's equator in near-infrared light moderately absorbed by atmospheric methane (top panel), and strongly absorbed by atmospheric methane (bottom panel). The four images that make up each of these mosaics were taken within a few minutes of each other. Methane in Jupiter's atmosphere absorbs light at specific wavelengths called absorption bands. By detecting light close and far from these absorption bands, Galileo can probe to different depths in Jupiter's atmosphere. Sunlight near 732 nanometers (top panel) is moderately absorbed by methane. Some of the light reflected from clouds deep in Jupiter's troposphere is absorbed, enhancing the higher features. Sunlight at 886 nanometers (bottom panel) is strongly absorbed by methane. Most of the light reflected from the deeper clouds is absorbed, making these clouds invisible. Features in the diffuse cloud layer higher in Jupiter's atmosphere are greatly enhanced. North is at the top. The mosaic covers latitudes -13 to +3 degrees and is centered at longitude 282 degrees West. The smallest resolved features are tens of kilometers in size. These images were taken on November 5th, 1996, at a range of 1.2 million kilometers by the Solid State Imaging system aboard NASA's Galileo spacecraft. 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

Winds Near Jupiter's Belt-Zo …

PIA01113

Sol (our sun)

Solid-State Imaging

Title	Winds Near Jupiter's Belt-Zone Boundary
Original Caption Released with Image	Time Sequence of a belt-zone boundary near Jupiter's equator. These mosaics show Jupiter's appearance at 757 nanometers (near-infrared) and were taken nine hours apart. Images at 757 nanometers show features of Jupiter's primary visible cloud deck. Jupiter's atmospheric circulation is dominated by alternating jets of east/west (zonal) winds. The bands have different widths and wind speeds but have remained constant as long as telescopes and spacecraft have measured them. A strong eastward jet is made visible as it stretches the clouds just below the center of this mosaic. The maximum wind speed of this jet is 128 meters per second (286 miles per hour). Features on this jet move about one quarter of the width of the mosaic. All the features visible in these mosaics are moving eastward (right). North is at the top. The mosaic covers latitudes -13 to +3 degrees and is centered at longitude 282 degrees West. The smallest resolved features are tens of kilometers in size. These images were taken on November 5th, 1996, at a range of 1.2 million kilometers by the Solid State Imaging system aboard NASA's Galileo spacecraft. 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

False Color Mosaic of Jupiter's Belt-Zone Boundary

False Color Mosaic of Jupite …

PIA01116

Sol (our sun)

Solid-State Imaging

Title	False Color Mosaic of Jupiter's Belt-Zone Boundary
Original Caption Released with Image	False-color mosaic of a belt-zone boundary near Jupiter's equator. The images that make up the four quadrants of this mosaic were taken within a few minutes of each other. Light at each of Galileo's three near-infrared wavelengths is displayed here mapped to the visible colors red, green, and blue. Light at 886 nanometers, strongly absorbed by atmospheric methane and scattered from clouds high in the atmosphere, is shown in red. Light at 732 nanometers, moderately absorbed by atmospheric methane, is shown in green. Light at 757 nanometers, scattered mostly from Jupiter's lower visible cloud deck, is shown in blue. The lower cloud deck appears bluish white, while the higher layer appears pinkish. The holes in the upper layer and their relationships to features in the lower cloud deck can be studied in the lower half of the mosaic. Galileo is the first spacecraft to image different layers in Jupiter's atmosphere. North is at the top. The mosaic covers latitudes -13 to +3 degrees and is centered at longitude 282 degrees West. The smallest resolved features are tens of kilometers in size. These images were taken on November 5th, 1996, at a range of 1.2 million kilometers by the Solid State Imaging system aboard NASA's Galileo spacecraft. 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

Very High Resolution Image of Icy Cliffs on Europa

Very High Resolution Image o …

PIA01182

Jupiter

Solid-State Imaging

Title	Very High Resolution Image of Icy Cliffs on Europa
Original Caption Released with Image	This image, taken by the camera onboard NASA's Galileo spacecraft, is a very high resolution view of the Conamara Chaos region on Jupiter's moon Europa. It shows an area where icy plates have been broken apart and moved around laterally. The top of this image is dominated by corrugated plateaus ending in icy cliffs over a hundred meters (a few hundred feet) high. Debris piled at the base of the cliffs can be resolved down to blocks the size of a house. A fracture that runs horizontally across and just below the center of the Europa image is about the width of a freeway. North is to the top right of the image, and the sun illuminates the surface from the east. The image is centered at approximately 9 degrees north latitude and 274 degrees west longitude. The image covers an area approximately 1.7 kilometers by 4 kilometers (1 mile by 2.5 miles). The resolution is 9 meters (30 feet) per picture element. This image was taken on December 16, 1997 at a range of 900 kilometers (540 miles) by Galileo's solid state imaging system. 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://www.jpl.nasa.gov/ galileo.

Europa Ice Cliffs-High Resol …

PIA01181

Jupiter

Solid-State Imaging

Title	Europa Ice Cliffs-High Resolution
Original Caption Released with Image	This view of the Conamara Chaos region on Jupiter's moon Europa shows cliffs along the edges of high-standing ice plates. The washboard texture of the older terrain has been broken into plates which are separated by material with a jumbled texture. The cliffs themselves are rough and broadly scalloped, and smooth debris shed from the cliff faces is piled along the base. For scale, the height of the cliffs and size of the scalloped indentations are comparable to the famous cliff face of Mount Rushmore in South Dakota. This image was taken on December 16, 1997 at a range of 900 kilometers (540 miles) by the solid state imaging system (camera) on NASA's Galileo spacecraft. North is to the top right of the picture, and the sun illuminates the surface from the east. This image, centered at approximately 8 degrees north latitude and 273 degrees west longitude, covers an area approximately 1.5 kilometers by 4 kilometers (0.9 miles by 2.4 miles). The resolution is 9 meters (30 feet) per picture element. The Jet Propulsion Laboratory, Pasadena, CA manages the Galileo mission for NASA's Office of Space Science, Washington, DC. JPL is an operating division of California Institute of Technology (Caltech). This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo mission home page at URL http://www.jpl.nasa.gov/ galileo.

Highest Resolution Image of …

PIA01180

Jupiter

Solid-State Imaging

Title	Highest Resolution Image of Europa
Original Caption Released with Image	During its twelfth orbit around Jupiter, on Dec. 16, 1997, NASA's Galileo spacecraft made its closest pass of Jupiter's icy moon Europa, soaring 200 kilometers (124 miles) kilometers above the icy surface. This image was taken near the closest approach point, at a range of 560 kilometers (335 miles) and is the highest resolution picture of Europa that will be obtained by Galileo. The image was taken at a highly oblique angle, providing a vantage point similar to that of someone looking out an airplane window. The features at the bottom of the image are much closer to the viewer than those at the top of the image. Many bright ridges are seen in the picture, with dark material in the low-lying valleys. In the center of the image, the regular ridges and valleys give way to a darker region of jumbled hills, which may be one of the many dark pits observed on the surface of Europa. Smaller dark, circular features seen here are probably impact craters. North is to the right of the picture, and the sun illuminates the surface from that direction. This image, centered at approximately 13 degrees south latitude and 235 degrees west longitude, is approximately 1.8 kilometers (1 mile) wide. The resolution is 6 meters (19 feet) per picture element. This image was taken on December 16, 1997 by the solid state imaging system camera on NASA's Galileo spacecraft. 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://www.jpl.nasa.gov/ galileo.

A New Hot Spot on Northern I …

PIA03602

Jupiter

Near Infrared Mapping Spectr …

Title	A New Hot Spot on Northern Io
Original Caption Released with Image	NASA's Galileo spacecraft has returned infrared imagery of a new hot spot on Jupiter's moon Io that was the source of a towering plume in August 2001, indicating a sulfur-dioxide concentration that may have been fallout from the plume. Galileo's near-infrared mapping spectrometer captured the image on the left during an Oct. 16, 2001 flyby of Io. Coloring indicates the intensity of glowing at a wavelength of 4.1 microns. Yellow, red, and white represent high temperatures. Black is where the near-infrared glow was so intense the image was saturated. Greens and blues are cold. The visible-light image on the right was obtained by Galileo's camera in 1999, before any volcanic activity was seen at this site. The first sign of activity came in August 2001, when Galileo detected an infrared hot spot and the tallest volcanic plume ever seen at Io. The dark blue band north of the hot spot in the new infrared image represents a concentration of sulfur-dioxide, which has a strong signature in the infrared. The sulfur-dioxide is thought to be from the fallout of the plume. The image shows high temperatures corresponding to yellow flows in the center of the visible-light image, and from a small caldera at the 8 o'lock position. 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 Galileo and its discoveries is available on the Galileo mission home page at http://galileo.jpl.nasa.gov [ http://galileo.jpl.nasa.gov ]. Background information and educational context for the images can be found at http://galileo.jpl.nasa.gov/gallery/io.cfm [ http://galileo.jpl.nasa.gov/gallery/io.cfm ].

Io's Tupan Caldera in Infrar …

PIA03601

Jupiter

Near Infrared Mapping Spectr …

Title	Io's Tupan Caldera in Infrared
Original Caption Released with Image	Tupan Caldera, a volcanic crater on Jupiter's moon Io, has a relatively cool area, possibly an island, in its center, as indicated by infrared imagery from NASA's Galileo spacecraft. A thermal portrait of Tupan collected by the near-infrared mapping instrument on Galileo during an Oct. 16, 2001 flyby is presented on the right, beside a visible-light image from Galileo's camera for geographical context. The infrared image uses false color to indicate intensity of glowing at a wavelength of 4.7 microns. Reds and yellows indicate hotter regions, blues are cold. The hottest areas correspond to the dark portions in the visible-light image and are probably hot lavas. The central region in the crater may be an island or a topographically high region. Parts of it are cold enough for sulfur-dioxide to condense. Tupan, an active volcano on Io since at least 1996, was named for the Brazilian native god of thunder. 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 Galileo and its discoveries is available on the Galileo mission home page at http://galileo.jpl.nasa.gov [ http://galileo.jpl.nasa.gov ]. Background information and educational context for the images can be found at http://galileo.jpl.nasa.gov/gallery/io.cfm [ http://galileo.jpl.nasa.gov/gallery/io.cfm ].

Nighttime Temperatures on So …

PIA03603

Jupiter

Photopolarimeter-Radiometer

Title	Nighttime Temperatures on Southern Io
Original Caption Released with Image	http://galileo.jpl.nasa.gov/gallery/io.cfm [ http://galileo.jpl.nasa.gov/gallery/io.cfm ]., Nighttime temperatures in the southern hemisphere of Jupiter's moon Io, mapped here with data from NASA's Galileo spacecraft, give hints about the textures of surface materials, as well as the locations of volcanic hot spots. The photopolarimeter/radiometer instrument on Galileo collected the information during an Aug. 6, 2001 flyby of Io, yielding the most detailed temperature map yet for this region. Features are visible as small as 150 kilometers (93 miles) across. The temperature map is superimposed here on images from Galileo's camera, covering volcanoes Pele (Pe), Pillan (Pi), Babbar (Ba) and others. It extends southward almost to Io's south pole. The contour interval is 2.5 degrees Kelvin (4.5 degrees Fahrenheit), but contours above 110 Kelvin (minus 262 Fahrenheit) have been omitted to reveal the volcanic hot spots that produce these relatively high temperatures. Some of the most interesting features on this map occur in the regions between the hot spots. The hot spot of the Pele volcano is surrounded by concentric temperature patterns that echo Pele's concentric rings of volcanic plume debris, which can be seen in full-color visible-light images. Close to the volcano, temperatures drop below 87 Kelvin (minus 303 Fahrenheit, among the coldest on Io), corresponding to a yellowish inner portion of material ejected from the volcano. A ring of higher temperatures, up to 105 Kelvin (minus 271 Fahrenheit), surrounds this cold area and coincides with an orange ring of volcanic debris seen in full-color visible-light images. These concentric temperature patterns probably reflect variations in the texture of the deposits from Pele's volcanic plume, because textures affect the surfaces' ability to retain heat through the night. The yellow material may be exceptionally fluffy, so it cools quickly at night, while the orange material is more compact and better at retaining heat. Also of interest is the strange fact, first noted on Galileo's February 2000 Io flyby, that nighttime temperatures do not drop off significantly between the equator and the poles. Because the nighttime temperatures away from the volcanoes are probably largely determined by sunlight absorbed during the previous day, and the poles receive less sunlight than the equator, lower nighttime temperatures are expected at high latitudes, just as on Earth. Temperatures between the volcanoes are typically in the range of 90 to 100 Kelvin (minus 298 to minus 280 Fahrenheit) regardless of latitude. 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 Galileo and its discoveries is available on the Galileo mission home page at http://galileo.jpl.nasa.gov [ http://galileo.jpl.nasa.gov ]. Background information and educational context for the images can be found at

Tall Mountain, Tohil Mons, o …

PIA03600

Jupiter

Solid-State Imaging

Title	Tall Mountain, Tohil Mons, on Io
Original Caption Released with Image	Dramatic shadows across a mountainous landscape on Jupiter's moon Io reveal details of the topography around a peak named Tohil Mons in this mosaic created from images taken by NASA's Galileo spacecraft in October 2001. Tohil Mons rises 5.4 kilometers (18,000 feet) above Io's surface, according to analysis of stereo imaging [ http://photojournal.jpl.nasa.gov/catalog/PIA02586 ] from earlier Galileo flybys of Io. The new images, with a resolution of 327 meters (1,070 feet) per picture element, were taken when the Sun was low in the sky, producing informative shadows. North is to the top and the Sun illuminates the surface from the upper right. The topographic features revealed include a very straight ridge extending southwest from the peak, 500- to 850-meter-high (1,640- to 2,790-foot-high) cliffs to the northwest and a curious pit immediately east of the peak. Major questions remain about how Io's mountains form and how they are related to Io's ubiquitous volcanoes. Although Io is extremely active volcanically, few of its mountains appear to be volcanoes. However, two volcanic craters do lie directly to the northeast of Tohil's peak, a smaller dark-floored one and a larger one at the very edge of the mosaic. Furthermore, the shape of the pit directly east of the peak suggests a volcanic origin. Galileo scientists will use these images to investigate the geologic history of Tohil Mons and its relationship to the neighboring volcanic features. The image is centered at 28 degrees south latitude and 161 degrees west longitude. 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 Galileo and its discoveries is available on the Galileo mission home page at http://galileo.jpl.nasa.gov [ http://galileo.jpl.nasa.gov ]. Background information and educational context for the images can be found at http://galileo.jpl.nasa.gov/gallery/io.cfm [ http://galileo.jpl.nasa.gov/gallery/io.cfm ].

Visible Jovian Aurora

PIA00605

Sol (our sun)

Solid-State Imaging

Title	Visible Jovian Aurora
Original Caption Released with Image	Jupiter's aurora on the night side of the planet is seen here at five different wavelengths. Jupiter's bright crescent, which is about half illuminated, is out of view to the right. North is at the top. The images are centered at 57 degrees north and 184 degrees West and were taken on April 2, 1997 at a range of 1.7 million kilometers (1.05 million miles) by the Solid State Imaging (SSI) camera system aboard NASA's Galileo spacecraft. Although Jupiter's aurora had been imaged from Earth in the ultraviolet and infrared, these are the first images at visible wavelengths, where most of the emission takes place. CLR stands for clear (no filter) and shows the integrated brightness at all wavelengths. The other panels show the violet, green, red, and 889 nanometer-wavelength filtered images. The brightness of the aurora is roughly independent of wavelength, at least at the spectral resolution obtainable with these filters. As on Earth, the aurora is caused by electrically charged particles striking the upper atmosphere, causing the molecules of the atmosphere to glow. The brightness in the different filters contains information about the energy of the impinging particles and the composition of the upper atmosphere. If atomic hydrogen were the only emitter, the light would be much stronger in the red filter, which is not consistent with the observed distribution. 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.

Close-up of Europa's Surface and similar scales on Earth

Close-up of Europa's Surface …

PIA00599

Jupiter

Solid-State Imaging

Title	Close-up of Europa's Surface and similar scales on Earth
Original Caption Released with Image	This is the fifth in a series of products at increasing resolutions that compare images of various areas on Jupiter's moon Europa [ http://photojournal.jpl.nasa.gov/catalog/PIA00592 ] (top frame) to the same location on Earth, the San Francisco Bay area of California (bottom frame). Both images show areas of equal size, 13 by 18 kilometers (8 by 11 miles), and resolution, 26 meters (28 yards). North is to the top of the picture. In this close-up view of Europa's icy surface, a flat smooth area about 3.2 kilometers (2 miles) across is seen in the left part of the picture. This area resulted from flooding by a fluid which erupted onto the surface and buried sets of ridges and grooves. The smooth area contrasts with a distinctly rugged patch of terrain farther east, to the right of the prominent ridge system running down the middle of the picture. Eruptions of material onto the surface, crustal disruption, and the formation of complex networks of folded and faulted ridges show that significant energy was available in the interior of Europa. The Sun illuminates the scene from the east (right). The San Francisco Bay area image helps to give a sense of scale to the predominant features in the Europa image above. Both the "flat smooth area" and the contrasting "rugged patch" are sufficiently large to cover all of downtown San Francisco. The Golden Gate Bridge, if on Europa's surface, would be long enough to span each of those features as well. The Europa image was obtained from a range of 2500 kilometers (1600 miles) by the Solid State Imaging (CCD) system aboard NASA's Galileo spacecraft on December 19th, 1996 (Universal Time). The San Francisco Bay area image, from the LandSat Thematic Mapper, has been reprocessed to match Galileo's resolution so as to offer a sense of the size of the features visible on Europa's surface. 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

Structurally Complex Surface of Europa and similar scales on Earth

Structurally Complex Surface …

PIA00598

Jupiter

Solid-State Imaging

Title	Structurally Complex Surface of Europa and similar scales on Earth
Original Caption Released with Image	This is the fourth in a series of five products at increasing resolutions that compare images of various areas on Jupiter's icy moon Europa [ http://photojournal.jpl.nasa.gov/catalog/PIA00543 ] (left frame) to the same location on Earth, the San Francisco Bay area of California (right frame). Both images show areas of equal size, 17 by 49 kilometers (11 by 30 miles), and resolution, 30 meters (100 feet). North is to the top of the picture. The frame on the left is a mosaic of two images of Europa and shows the surface to be structurally complex. The sun illuminates the scene from the east, revealing complex overlapping ridges and fractures in the upper and lower portions of the frame, and rugged, more chaotic terrain in the center. Lateral faulting is revealed where ridges show offsets along their lengths (upper left of the frame). Missing ridge segments indicate obliteration of pre-existing materials and emplacement of new terrain (center of the frame). The surface of San Francisco rivals that of Europa. In this 30 meter resolution comparison image, the complex pattern of city streets is clearly visible as are the many piers that line the water front district (upper right). This Bay area scene is also illuminated from the east. Notice the shadow of the Bay Bridge on the surface of the water as it makes its way to Oakland and the east bay. In the upper left corner, a ship can be seen making its way to the mouth of the bay. The Europa image was obtained from a range of 3410 kilometers (2119 miles) by the Solid State Imaging (CCD) system aboard NASA's Galileo spacecraft on December 19th, 1996 (Universal Time). The San Francisco Bay area image, from the LandSat Thematic Mapper, has been reprocessed to match Galileo's resolution so as to offer a sense of the size of the features visible on Europa's surface. 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

Icy Europa and similar scale …

PIA00595

Jupiter

Solid-State Imaging

Title	Icy Europa and similar scales on Earth
Original Caption Released with Image	This is the first in a series of products that compare images at increasing resolutions of various areas on Jupiter's icy moon Europa [ http://photojournal.jpl.nasa.gov/catalog/PIA00539 ] (top frame) to the same location on Earth, the San Francisco Bay area of California (bottom frame). Both images show areas of roughly equal size, 252 by 393 kilometers (157 by 244 miles), and resolution, 630 meters (690 yards). This means that the smallest identifiable feature is less than a mile across (2 pixels wide). North is to the top of the picture. The sun illumination from the right in the Europa image reveals several ridges crossing the scene, plateaus commonly several miles (10 km) across, and patches of smooth, low-lying darker materials. No prominent impact craters are visible, indicating the surface in this location is not geologically ancient. Some ridges have gaps, and subtle textural differences in these areas indicate that missing ridge segments probably were swept away by volcanic flows. The flow deposits are probably composed mainly of water ice, the chief constituent of the surface of Europa. The Earth based image (lower frame) covers an area stretching from San Francisco Bay (top left) to the Nevada border (top right) and from Mono Lake in (top center) to the Mojave Desert (bottom right). Other predominant geographic features include the snow capped Sierra Nevada Mountains and California's Great Central Valley (center frame). The Europa image was obtained from a range of 62089 kilometers (39028 miles) by the Solid State Imaging (CCD) system aboard NASA's Galileo spacecraft on December 19th, 1996 (Universal Time). The San Francisco Bay area image, from the NOAA satellite's Advanced Very High Resolution Radiometer (AVHRR) instrument, has been reprocessed to roughly match Galileo's resolution so as to offer a sense of the size of the features visible on Europa's surface. The Jet Propulsion Laboratory, Pasadena, CA, manages the mission for NASA's Office of Space Science, Washington D.C. 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.

Close-up of Europa's Trailing Hemisphere and similar scales on Earth

Close-up of Europa's Trailin …

PIA00596

Jupiter

Solid-State Imaging

Title	Close-up of Europa's Trailing Hemisphere and similar scales on Earth
Original Caption Released with Image	This is the second in a series of five products at increasing resolutions that compare images of various areas on Jupiter's icy moon Europa [ http://photojournal.jpl.nasa.gov/catalog/PIA00587 ] (top frame) to the same location on Earth, the San Francisco Bay area of California (bottom frame). Both images show areas of equal size, 100 by 140 kilometers (62 by 87 miles), and resolution, 180 meters (200 yards). This means that the smallest visible object is about a quarter of a mile across. North is to the top of the picture. This complex terrain shows an area centered at 8 degrees north latitude, 275.4 degrees west longitude, in the trailing hemisphere. As Europa moves in its orbit around Jupiter, the trailing hemisphere is the portion which is always on the moon's backside opposite to its direction of motion. The complex ridge crossing the picture in the upper left corner is part of a feature that can be traced hundreds of miles across the surface of Europa, extending beyond the edge of the picture. The upper right part of the picture shows terrain that has been disrupted by an unknown process, superficially resembling blocks of sea ice during a springtime thaw. Also visible are semicircular mounds surrounded by shallow depressions. These might represent the intrusion of material punching through the surface from below and partial melting of Europa's icy crust. In the San Francisco Bay area image, the level of detail is such that jigsaw puzzle like patterns of agricultural fields can be seen in the upper right corner and some levels of physical relief can be detected in the coastal mountain ranges. Also discernible at this resolution are the vast urban areas along the shores of the bay. Alcatraz Island appears as a tiny speck at center frame. The Europa image was obtained from a range of 17,900 kilometers (11,100 miles) by the Solid State Imaging (CCD) system aboard NASA's Galileo spacecraft on February 20th, 1997 (Universal Time). The San Francisco Bay area image, from the LandSat Thematic Mapper, has been reprocessed to match Galileo's resolution so as to offer a sense of the size of the features visible on Europa's surface. 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

Europa Ice Rafts and similar scales on Earth

Europa Ice Rafts and similar …

PIA00597

Jupiter

Solid-State Imaging

Title	Europa Ice Rafts and similar scales on Earth
Original Caption Released with Image	This is the third in a series of five products at increasing resolutions that compare images of various areas on Jupiter's moon Europa [ http://photojournal.jpl.nasa.gov/catalog/PIA00591 ] (top frame) to the same location on Earth, the San Francisco Bay area of California (bottom frame). Both images show areas of equal size, 34 by 42 kilometers (21 by 26 miles), and resolution, 54 meters (59 yards). North is to the top of the picture. This high resolution image shows Europa's ice-rich crust with crustal plates ranging up to 13 kilometers (8 miles) across, which have been broken apart and "rafted" into new positions, superficially resembling the disruption of pack-ice on polar seas during spring thaws on Earth. The size and geometry of these features suggest that motion was enabled by ice-crusted water or soft ice close to the surface at the time of disruption. This Europa image is centered at 9.4 degrees north latitude, 274 degrees west longitude, The San Francisco Bay portion of this image pair helps to give the viewer some sense of scale as it relates to the size of the Europa "ice rafts." Look, for example, at the cratered "ice raft" in the lower left hand portion of the Europa image. Compare that to such features in the Bay area image as Treasure Island Naval Station, (center frame) and the San Francisco International Airport (bottom right). Also in this image, at 54 meters resolution, structural features such as the Golden Gate Bridge and the Bay Bridge are clearly visible. The Europa image was obtained from a range of 5,340 kilometers (3,320 miles) by the Solid State Imaging (CCD) system aboard NASA's Galileo spacecraft on February 20th, 1997 (Universal Time). The San Francisco Bay area image, from the LandSat Thematic Mapper, has been reprocessed to match Galileo's resolution so as to offer a sense of the size of the features visible on Europa's surface. 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

Thunderheads on Jupiter

PIA00506

Sol (our sun)

Solid-State Imaging

Title	Thunderheads on Jupiter
Original Caption Released with Image	Scientists have spotted what appear to be thunderheads on Jupiter bright white cumulus clouds similar to those that bring thunderstorms on Earth - at the outer edges of Jupiter's Great Red Spot. Images from NASA's Galileo spacecraft now in orbit around Jupiter are providing new evidence that thunderstorms may be an important source of energy for Jupiter's winds that blow at more than 500 kilometers per hour (about 300 miles per hour). The photos were taken by Galileo's solid state imager camera on June 26, 1996 at a range of about 1.4 million kilometers (about 860,000 miles). The image at top is a mosaic of multiple images taken through near-infrared filters. False coloring in the image reveals cloud-top heights. High, thick clouds are white and high, thin clouds are pink. Low-altitude clouds are blue. The two black-and-white images at bottom are enlargements of the boxed area, the one on the right was taken 70 minutes after the image on the left. The arrows show where clouds have formed or dissipated in the short time between the images. The smallest clouds are tens of kilometers across. On Earth, moist convection in thunderstorms is a pathway through which solar energy, deposited at the surface, is transported and delivered to the atmosphere. Scientists at the California Institute of Technology analyzing data from Galileo believe that water, the most likely candidate for what composes these clouds on Jupiter, may be more abundant at the site seen here than at the Galileo Probe entry site, which was found to be unexpectedly dry. 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

A Record of Crustal Movement …

PIA01643

Jupiter

Solid-State Imaging

Title	A Record of Crustal Movement on Europa
Original Caption Released with Image	This view of the south polar region of Jupiter's moon Europa shows part of a gray band that formed as plates on the icy surface separated and material filled in the widening gap. North is to the top of the picture. In the center of the image, a gently curving linear crack runs north to south and appears to be the location where the fault originally opened. Successive layers, like tree rings, form as material enters the gap periodically from below and hardens. The relative motion of the two opposing sides of the band is mostly "strike-slip," where two crustal blocks move horizontally past one another, similar to two opposing lanes of traffic. However, since this motion is not exactly parallel to the active crack, the opposite sides also pull apart to create openings through which warmer, softer ice from below Europa's brittle ice shell surface, or frozen water from a possible subsurface ocean, could reach the surface. The band surface accumulates layer by layer. A rough symmetry with respect to the active central linear crack can be seen in these layers. The large, segmented crack paralleling the west (left) side of the band cuts the original north to south fault shown in the center of the image. This suggests that the central fault has not been active since the large, segmented crack formed. The curved, lined area is a small part of a much larger strike-slip fault called Astypalaea Linea. [ http://photojournal.jpl.nasa.gov/catalog/PIA01644 ] This fault extends over 800 kilometers (500 miles), roughly the distance of the portion of California's San Andreas fault from the Mexican border to the San Francisco Bay. Galileo images show that the Europan fault has slipped about 50 kilometers (30 miles). The Sun illuminates the surface from the top. The image, centered at 66 degrees south latitude and 195 degrees west longitude, covers an area approximately 24 by 16 kilometers (15 by 10 miles). The resolution is 40 meters (131 feet) per picture element. The images were taken on September 26, 1998 at a range of less than 4,200 kilometers (2,600 miles) by Galileo's solid-state imaging system. 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 ]

Potential Source of Sulfur F …

PIA03887

Jupiter

Solid-State Imaging

Title	Potential Source of Sulfur Flow on Io
Original Caption Released with Image	A field of bright lava flows next to a shield volcano could be a source of recent sulfur volcanism on Io, as detected by instruments aboard NASA's Galileo spacecraft. The mosaic at left combines higher-resolution images (330 meters or about 1080 feet per picture element) taken in October 2001 with lower-resolution color images (1.4 kilometers or 0.9 mile per picture element) taken in July 1999 by Galileo's solid-state imaging camera. By comparing these images with a map of hot spots taken in February by Galileo's near-infrared mapping spectrometer (lower right), Galileo scientists noted that a new hot spot west of the active volcano Prometheus became bright in February 2000 and dimmed later. This hot spot appears to correspond with the bright flow field just west of a recently discovered shield volcano (see PIA03532 [ http://photojournal.jpl.nasa.gov/catalog/PIA03532 ]), which is the only fresh volcanic material in the area. The relatively low intensity of the February 2000 hot spot in the infrared data suggests a low-temperature eruption, consistent with sulfur lava rather than silicate lava as found elsewhere on Io and also on Earth. Sulfur lavas are thought to cool to a gray-yellow color on Io, as seen in the new flow field visible in the camera image. This bright flow field could be the best example of active sulfur lava flows deposited on Io during the Galileo mission. At upper right is a global view of Io showing the location of the more-detailed images. The low temperature of this hot spot differs from many of Io's other active volcanoes, such as Pele, Tvashtar and Prometheus. Intense tidal flexing of Io helps keep the moon's interior molten, at some places producing silicate lavas hotter than any seen on Earth in billions of years. Io has the greatest known diversity of volcanic activity in the solar system. North is to the top of all these images. 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 Galileo and its discoveries is available on the Galileo mission home page at http://galileo.jpl.nasa.gov [ http://galileo.jpl.nasa.gov ] . Background information and educational context for the images can be found at http://galileo.jpl.nasa.gov/gallery/io.cfm [ http://galileo.jpl.nasa.gov/gallery/io.cfm ].

Mountains on Io at Sunset

PIA03886

Jupiter

Solid-State Imaging

Title	Mountains on Io at Sunset
Original Caption Released with Image	NASA's Galileo spacecraft captured this dramatic image of mountains on Io in February 2000. The image was taken when the Sun was low in the sky, illuminating the scene from the left, so it reveals topographic details of Io's surface. A low scarp, roughly 250 meters (820 feet) high, runs from the upper left toward the center of the image. Mongibello Mons, the jagged ridge at the left of the image, rises 7 kilometers (23,000 feet) above the plains of Io, higher than any mountain in North America. Few of Io's mountains (see also PIA02526 [ http://photojournal.jpl.nasa.gov/catalog/PIA02526 ]) resemble volcanoes. Instead, Galileo scientists believe that the mountains are formed when blocks of Io's crust are uplifted along thrust faults. Angular mountains are thought to be younger, while older mountains have more subdued topography, such as the rise near the top center of this image. The image has a resolution of 335 meters (1,100 feet) per picture element. North is to the top of the image. 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 Galileo and its discoveries is available on the Galileo mission home page at http://galileo.jpl.nasa.gov [ http://galileo.jpl.nasa.gov ] . Background information and educational context for the images can be found at http://galileo.jpl.nasa.gov/gallery/io.cfm [ http://galileo.jpl.nasa.gov/gallery/io.cfm ].

Ruddy "Freckles" on Europa

PIA03878

Jupiter

Solid-State Imaging

Title	Ruddy "Freckles" on Europa
Original Caption Released with Image	Reddish spots and shallow pits pepper the enigmatic ridged surface of Europa in this view combining information from images taken by NASA's Galileo spacecraft during two different orbits around Jupiter. The spots and pits visible in this region of Europa's northern hemisphere are each about 10 kilometers (6 miles) across. The dark spots are called "lenticulae," the Latin term for freckles. Their similar sizes and spacing suggest that Europa's icy shell may be churning away like a lava lamp, with warmer ice moving upward from the bottom of the ice shell while colder ice near the surface sinks downward. Other evidence has shown that Europa likely has a deep melted ocean under its icy shell. Ruddy ice erupting onto the surface to form the lenticulae may hold clues to the composition of the ocean and to whether it could support life. The image combines higher-resolution information obtained when Galileo flew near Europa on May 31, 1998, during the spacecraft's 15th orbit of Jupiter, with lower-resolution color information obtained on June 28, 1996, during Galileo's first orbit. 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 Galileo and its discoveries is available on the Galileo mission home page at http://galileo.jpl.nasa.gov .

San Andreas-sized Strike-slip Fault on Europa

San Andreas-sized Strike-sli …

PIA01644

Jupiter

Solid-State Imaging

Title	San Andreas-sized Strike-slip Fault on Europa
Original Caption Released with Image	This mosaic of the south polar region of Jupiter's moon Europa shows the northern 290 kilometers (180 miles) of a strike-slip fault named Astypalaea Linea. The entire fault is about 810 kilometers (500 miles) long, about the size of the California portion of the San Andreas fault, which runs from the California-Mexico border north to the San Francisco Bay. In a strike-slip fault, two crustal blocks move horizontally past one another, similar to two opposing lanes of traffic. Overall motion along the fault seems to have followed a continuous narrow crack along the feature's entire length, with a path resembling steps on a staircase crossing zones that have been pulled apart. The images show that about 50 kilometers (30 miles) of displacement have taken place along the fault. The fault's opposite sides can be reconstructed like a puzzle, matching the shape of the sides and older, individual cracks and ridges broken by its movements. The red line marks the once active central crack of the fault. The black line outlines the fault zone, including material accumulated in the regions which have been pulled apart. Bends in the fault have allowed the surface to be pulled apart. This process created openings through which warmer, softer ice from below Europa's brittle ice shell surface, or frozen water from a possible subsurface ocean, could reach the surface. This upwelling of material formed large areas of new ice within the boundaries of the original fault. A similar pulling-apart phenomenon can be observed in the geological trough surrounding California's Salton Sea, in Death Valley and the Dead Sea. In those cases, the pulled-apart regions can include upwelled materials, but may be filled mostly by sedimentary and eroded material from above. One theory is that fault motion on Europa is induced by the pull of variable daily tides generated by Jupiter's gravitational tug on Europa. Tidal tension opens the fault and subsequent tidal stress causes it to move lengthwise in one direction. Then tidal forces close the fault again, preventing the area from moving back to its original position. Daily tidal cycles produce a steady accumulation of lengthwise offset motions. Here on Earth, unlike Europa, large strike-slip faults like the San Andreas are set in motion by plate tectonic forces. North is to the top of the picture and the sun illuminates the surface from the top. The image, centered at 66 degrees south latitude and 195 degrees west longitude, covers an area approximately 300 by 203 kilometers(185 by 125 miles). The pictures were taken on September 26, 1998by Galileo's solid-state imaging system. 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

San Andreas-sized Strike-sli …

PIA01644

Jupiter

Solid-State Imaging

Title	San Andreas-sized Strike-slip Fault on Europa
Original Caption Released with Image	This mosaic of the south polar region of Jupiter's moon Europa shows the northern 290 kilometers (180 miles) of a strike-slip fault named Astypalaea Linea. The entire fault is about 810 kilometers (500 miles) long, about the size of the California portion of the San Andreas fault, which runs from the California-Mexico border north to the San Francisco Bay. In a strike-slip fault, two crustal blocks move horizontally past one another, similar to two opposing lanes of traffic. Overall motion along the fault seems to have followed a continuous narrow crack along the feature's entire length, with a path resembling steps on a staircase crossing zones that have been pulled apart. The images show that about 50 kilometers (30 miles) of displacement have taken place along the fault. The fault's opposite sides can be reconstructed like a puzzle, matching the shape of the sides and older, individual cracks and ridges broken by its movements. The red line marks the once active central crack of the fault. The black line outlines the fault zone, including material accumulated in the regions which have been pulled apart. Bends in the fault have allowed the surface to be pulled apart. This process created openings through which warmer, softer ice from below Europa's brittle ice shell surface, or frozen water from a possible subsurface ocean, could reach the surface. This upwelling of material formed large areas of new ice within the boundaries of the original fault. A similar pulling-apart phenomenon can be observed in the geological trough surrounding California's Salton Sea, in Death Valley and the Dead Sea. In those cases, the pulled-apart regions can include upwelled materials, but may be filled mostly by sedimentary and eroded material from above. One theory is that fault motion on Europa is induced by the pull of variable daily tides generated by Jupiter's gravitational tug on Europa. Tidal tension opens the fault and subsequent tidal stress causes it to move lengthwise in one direction. Then tidal forces close the fault again, preventing the area from moving back to its original position. Daily tidal cycles produce a steady accumulation of lengthwise offset motions. Here on Earth, unlike Europa, large strike-slip faults like the San Andreas are set in motion by plate tectonic forces. North is to the top of the picture and the sun illuminates the surface from the top. The image, centered at 66 degrees south latitude and 195 degrees west longitude, covers an area approximately 300 by 203 kilometers(185 by 125 miles). The pictures were taken on September 26, 1998by Galileo's solid-state imaging system. 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

Io's Gish Bar Volcanic Region in Infrared

Io's Gish Bar Volcanic Regio …

PIA03888

Jupiter

Solid-State Imaging

Title	Io's Gish Bar Volcanic Region in Infrared
Original Caption Released with Image	An infrared thermal map and a visible-light image from NASA's Galileo spacecraft show the likelihood of an active lava lake at a volcanic feature called Gish Bar on Jupiter's moon Io. Galileo observed the Gish Bar region with the spacecraft's near-infrared mapping spectrometer instrument in August 2001 (right) and with its solid-state imaging camera in October 2001 (left). Comparison of the camera image with the infrared thermal map and with earlier images, (see PIA03884 [ http://photojournal.jpl.nasa.gov/catalog/PIA03884 ]) suggests that a new eruption took place shortly before the October 2001 flyby. The darkest areas in the visible-light image are interpreted as the youngest lava flows, but they do not correspond with the hottest areas in the infrared thermal map from two months earlier. Outlines of the areas that were identified as hotter than 350 degrees Kelvin (170 degrees Fahrenheit) in the thermal map are superimposed on the visible-light image. North is toward the top. The dark flow on the western side of the crater in October corresponds to a cool area in the earlier thermal map, indicating that the flow took place between the time Galileo flew by in August and the time it flew by in October. 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 Galileo and its discoveries is available on the Galileo mission home page at http://galileo.jpl.nasa.gov [ http://galileo.jpl.nasa.gov ] . Background information and educational context for the images can be found at http://galileo.jpl.nasa.gov/gallery/io.cfm [ http://galileo.jpl.nasa.gov/gallery/io.cfm ].

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