Search Results: All Fields similar to 'Galileo' and Where equal to 'California'

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Changes around Marduk betwee …
PIA01066
Jupiter
Solid-State Imaging
Title Changes around Marduk between Voyager, and Galileo's first two orbits
Original Caption Released with Image Detail of changes around Marduk on Jupiter's moon Io as seen by Voyager 1 in 1979 (upper left) and NASA's Galileo spacecraft between June 1996 (lower left) and September 1996 (upper and lower right). The new dark red linear feature extending southeast from Marduk is about 250 kilometers long and may be a volcanic fissure. The flow-like feature at the bottom of the images is distinct in the Voyager data, indistinct in the June Galileo data, but distinct again in the September Galileo data. This may be due to the different lighting conditions rather than volcanic activity. The Voyager 1 image uses the green, blue, and violet filters. The upper right September 1996 image from Galileo uses the violet and green filters of the solid state imaging system aboard the Galileo spacecraft and a synthetic blue to simulate Voyager colors. The lower June and September, 1996 Galileo images use the imaging system's near-infrared (756 nm), green, and violet filters. North is to the top in all frames. 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
Io's Tohil Mons in Different …
Images taken by NASA's Galil …
2/26/01
Date 2/26/01
Description Images taken by NASA's Galileo spacecraft with different angles of sunlight help scientists interpret the three- dimensional shape of structures on Jupiter's moons. This pair shows a mountain named Tohil Mons on the innermost of Jupiter's four large moons, Io. The top image was taken at low resolution and a low Sun angle during Galileo's third orbit, in 1996. Because the Sun is low, topographic features on the mountain can be recognized from the shadows they cast. Labels indicate the peak of the mountain and two volcanic depressions, called paterae. The bottom image was taken on Feb. 22, 2000, at higher resolution and a higher Sun angle. The smallest visible features are about 165 meters (540 feet) across. The topography is almost indistinguishable, but many more details can be discerned. By combining several observations in this manner, Galileo scientists are able to study Io's mountains and to learn about their evolution and their relationship to Io's volcanoes. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the Galileo mission for NASA's Office of Space Science, Washington, D.C. Images and data received from Galileo are posted on the Galileo mission home page at http://www.jpl.nasa.gov/galileo. Background information and educational context for the images can be found at http://www.jpl.nasa.gov/galileo/sepo . # # # # #
Galilean Moon Interiors
This artist's concept shows …
6/4/98
Date 6/4/98
Description This artist's concept shows cross-sections of the four largest moons of Jupiter, with the interior structures based on the latest information sent back by NASA's Galileo spacecraft. The moons depicted are (clockwise from bottom right) Callisto, Ganymede, Io and Europa. Scientists have modified their concept of Callisto's interior, based on the most recent Galileo findings. Whereas previously they believed that Callisto was completely undifferentiated, with a uniform mixture of rock and ice, scientists now say the interior has some separation of the ice and rock, but not nearly as much as the other three moons. Galileo data indicate that Ganymede is separated into a metallic core, rock mantle, and ice-rich outer shell, while Io has a metallic core and rock mantle, but no ice. Galileo data has also helped scientists refine their model of Europa's structure. They believe Europa has a metallic core surrounded by a rock mantle and a water ice-liquid outer shell. The core may be up to half the size of Europa's radius, with the water ice-liquid shell estimated to be between 80 to 170 kilometers thick (50 to 106 miles), with 100 kilometers (62 miles) considered the most likely thickness. Information on the interior structure of the four moons was obtained by studying radio Doppler data that is gathered when Galileo flies by the satellites. Each moon exerts a gravitational tug, but the tug's strength is determined by how much rock is contained within the moon (the higher the rock content, the stronger the tug). The tug changes the spacecraft's speed and the radio frequency of its signals. Scientists study those changes to determine the rock content and structure of the moon. This material was presented to the American Astronomical Society meeting in San Diego, CA on June 4, 1998. The Jet Propulsion Laboratory, Pasadena, CA manages the Galileo mission for NASA's Office of Space Science, Washington, DC. JPL is a division of California Institute of Technology (Caltech). This image, along with other images and data received from Galileo, is available on the Galileo mission home page at http://www.jpl.nasa.gov/galileo. Background information and educational context for the images can be found at http://www.jpl.nasa.gov/galileo/sepo . #####
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
Lack of visible change aroun …
PIA01065
Jupiter
Solid-State Imaging
Title Lack of visible change around active hotspots on Io
Original Caption Released with Image Detail of changes around two hotspots on Jupiter's moon Io as seen by Voyager 1 in April 1979 (left) and NASA's Galileo spacecraft on September 7th, 1996 (middle and right). The right frame was created with images from the Galileo Solid State Imaging system's near-infrared (756 nm), green, and violet filters. For better comparison, the middle frame mimics Voyager colors. The calderas at the top and at the lower right of the images correspond to the locations of hotspots detected by the Near Infrared Mapping Spectrometer aboard the Galileo spacecraft during its second orbit. There are no significant morphologic changes around these hot calderas, however, the diffuse red deposits, which are simply dark in the Voyager colors, appear to be associated with recent and/or ongoing volcanic activity. The three calderas range in size from approximately 100 kilometers to approximately 150 kilometers in diameter. The caldera in the lower right of each frame is named Malik. North is to the top of all frames. 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
Changes east of Pele between …
PIA01068
Jupiter
Solid-State Imaging
Title Changes east of Pele between Galileo's first two orbits
Original Caption Released with Image Detail of changes east of Pele on Jupiter's moon Io as seen by NASA's Galileo spacecraft between June (left) and September (right) 1996. The caldera at the center of the images that changes from bright to dark is approximately 80 kilometers in diameter. Some scientists speculate that this brightness (albedo) change might be due to flooding of the crater floor by lava. The left frame was reprojected and stretched to match the geometry and average colors of the right frame. Before this stretch, the earlier image (left) was significantly redder than the later image (right), this may be due to variations in lighting. Both frames were created with images from the Galileo Solid State Imaging system's near-infrared (756 nm), green, and violet filters. North is to the top of both frames. 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
Galileo and Cassini Image: T …
Two Giant Plumes on Io ,Two …
3/29/01
Date 3/29/01
Description Two Giant Plumes on Io ,Two tall volcanic plumes and the rings of red material they have deposited onto surrounding surface areas appear in images taken of Jupiter's moon Io by NASA's Galileo and Cassini spacecraft in late December 2000 and early January 2001. One plume, from the volcano Pele, shoots upward nearly 400 kilometers (250 miles) from the surface near Io's equator. The plume has been active for at least four years and, until now, had been far larger than any other plume seen on Io. The images also show a second plume about the same size, closer to Io's north pole. This plume had never been seen before. It is associated with a fresh eruption from the Tvashtar Catena volcanic area. The observations were made during joint studies of the Jupiter system while Cassini was passing Jupiter on its way to Saturn. Galileo passed closer to Io for higher-resolution images, and Cassini acquired images at ultraviolet wavelengths, better for detecting active volcanic plumes. The Cassini ultraviolet images, upper right, reveal two gigantic, actively erupting plumes of gas and dust. Near the equator, just the top of Pele's plume is visible where it projects into sunlight. None of it would be illuminated if it were less than 240 kilometers (150 miles) high. These images indicate a total height for Pele of 390 kilometers (242 miles). The Cassini image at far right shows a bright spot over Pele's vent. Although the Pele hot spot has a high temperature, silicate lava cannot be hot enough to explain a bright spot in the ultraviolet, so the origin of this bright spot is a mystery, but it may indicate that Pele was unusually active when the picture was taken. Also visible is a plume near Io's north pole. Although 15 active plumes over Io's equatorial regions have been detected in hundreds of images from NASA's Voyager and Galileo spacecraft, this is the first image ever acquired of an active plume over a polar region of Io. The plume projects about 150 kilometers (about 90 miles) over the limb, the edge of the globe. If it were erupting from a point on the limb, it would be only slightly larger than a typical Ionian plume, but the image does not reveal whether the source is actually at the limb or beyond it, out of view. A distinctive feature in Galileo images since 1997 has been a giant red ring of Pele plume deposits about 1,400 kilometers (870 miles) in diameter. The Pele ring is seen again in one of the new Galileo images, lower left. When the new Galileo images were returned this month, scientists were astonished to see a second giant red ring on Io, centered around Tvashtar Catena at 63 degrees north latitude. (To see a comparison from before the ring was deposited, see images PIA-01604 or PIA-02309.) Tvashtar was the site of an active curtain of high-temperature silicate lava imaged by Galileo in November 1999 and February 2000 (image PIA- 02584). The new ring shows that Tvashtar must be the vent for the north polar plume imaged by Cassini from the other side of Io. This means the plume is actually about 385 kilometers (239 miles) high, just like Pele. The uncertainty in estimating the height is about 30 kilometers (19 miles), so the plume could be anywhere from 355 to 415 kilometers (221 to 259 miles) high. If this new plume deposit is just one millimeter (four one- hundredths of an inch) thick, then the eruption produced more ash than the 1980 eruption of Mount St. Helens in Washington. NASA recently approved a third extension of the Galileo mission, including a pass over Io's north pole in August 2001. The spacecraft's trajectory will pass directly over Tvashtar at an altitude of 200 kilometers (124 miles). Will Galileo fly through an active plume? That depends on whether this eruption is long- lived like Pele or brief, and it also depends on how high the plume is next August. Two Pele-sized plumes are inferred to have erupted in 1979 during the four months between Voyager 1 and Voyager 2 flybys, as indicated by new Pele-sized rings in Voyager 2 images. Those eruptions, both from high-latitude locations, were shorter-lived than Pele, but their actual durations are unknown. In May, Galileo will get another, more distant look at Tvashtar. It has been said that Io is the heartbeat of the jovian magnetosphere. The two giant plumes evidenced in these images may have had significant effects on the types, density and distribution of neutral and charged particles in the Jupiter system during the joint observations of the system by Galileo and Cassini from November 2000 to March 2001. These Cassini images were acquired on Jan. 2, 2001, except for the frame at the far right, which was acquired a day earlier. The Galileo images were acquired on Dec. 30 and 31, 2000. Cassini was about 10 million kilometers (6 million miles) from Io, 10 times farther than Galileo. More information about the Cassini and Galileo joint observations of the Jupiter system is available online at http://www.jpl.nasa.gov/jupiterflyby . Cassini is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the Galileo and Cassini missions for NASA's Office of Space Science, Washington, D.C.
Eruption at Tvashtar Catena …
This pair of images taken by …
2/26/01
Date 2/26/01
Description This pair of images taken by NASA's Galileo spacecraft captures a dynamic eruption at Tvashtar Catena, a chain of volcanic bowls on Jupiter's moon Io. They show a change in the location of hot lava over a period of a few months in 1999 and early 2000. The image on the left uses data obtained on Nov. 26 and July 3, 1999, at resolutions of 183 meters (600 feet) and 1.3 kilometers (0.8 miles) per pixel, respectively. The red and yellow lava flow itself is an illustration based upon imaging data. The image on the right is a composite using a five-color observation made on Feb. 22, 2000, at 315 meters (1030 feet) per pixel. These are among the most fortuitous observations made by Galileo because this style of volcanism is too unpredictable and short-lived to plan to photograph. Short-lived bursts of volcanic activity on Io had been previously detected from Earth-based observations, but interpreting the style of volcanic activity from those lower- resolution views was highly speculative. These Galileo observations confirm hypotheses that the initial, intense thermal output comes from active lava fountains. Galileo's high-resolution observations of volcanic activity on Io have also confirmed other hypotheses based on earlier, low- resolution data. These include interpretations of slowly spreading lava flows at Prometheus and Amirani and an active lava lake at Pele. These tests of earlier hypotheses increase scientists' confidence in interpreting volcanic activity seen in low-resolution remote sensing data of Earth as well as Io. However, these data are still of insufficient resolution to adequately test the more quantitative models that have been applied to volcanic eruptions on Earth and Io. These images also show other geologic features on Io, such as the scalloped margins of the plateau to the northeast of the active lavas. These margins appear to have formed by sapping, a process usually associated with springs of water. Liquid sulfur dioxide might be the fluid responsible for sapping on Io. A better understanding of sapping on Io will influence how scientists interpret similar features on Mars (where the viability of carbon dioxide or water as the sapping fluid remains controversial). Images and data received from Galileo are posted on the Galileo mission home page at http://www.jpl.nasa.gov/galileo. Background information and educational context for the images can be found at http://www.jpl.nasa.gov/galileo/sepo . The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the Galileo mission for NASA's Office of Space Science, Washington, D.C. # # # # #
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 ].
Changes on Io around Maui an …
PIA01067
Jupiter
Solid-State Imaging
Title Changes on Io around Maui and Amirani between Voyager 1 and Galileo's second orbit
Original Caption Released with Image Detail of changes on Jupiter's moon Io in the region around Maui and Amirani as seen by the Voyager 1 spacecraft in April 1979 (left frame) and NASA's Galileo spacecraft in September 1996 (right frame). North is to the top of both frames. The dark, north - south running linear feature, Amirani, is approximately 350 km long. Maui is the large circular feature immediately west of the southern end of Amirani. Note the brightening of the west side of Maui and the bright patch on the west side of Amirani. 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
Changes on Io around Volund …
PIA01071
Jupiter
Solid-State Imaging
Title Changes on Io around Volund between Voyager 1 and Galileo's second orbit
Original Caption Released with Image Detail of changes on Jupiter's moon Io in the region around Volund as seen by the Voyager 1 spacecraft in April 1979 (left frame) and NASA's Galileo spacecraft in September 1996 (right frame). North is to the top of both frames which are approximately 600 kilometers by 600 kilometers. Note the new linear feature, which may be a volcanic fissure, trending east from the southern end of Volund. Dark diffuse material lies to the west and a ring of bright material which may be SO2- rich plume deposits appears to be centered near the middle of the new linear feature. 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
Galileo's First Image of Ama …
PIA01072
Jupiter
Solid-State Imaging
Title Galileo's First Image of Amalthea
Original Caption Released with Image Galileo's first view of Amalthea, a small inner moon of Jupiter, showing the end of the elongated satellite that faces permanently toward the giant planet. North is to the top of the picture and the Sun illuminates the surface from the left. The circular feature that dominates the upper-right portion of the disk is Pan, the largest crater on Amalthea. This crater is about 90 kilometers wide. The bright spot at the south pole is associated with another, slightly smaller crater named Gaea. The Universal Time is 8 hours, 18 minutes, 0 seconds on the 7th of September, 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 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
Two Galileo Views of Thebe
PIA01075
Jupiter
Solid-State Imaging
Title Two Galileo Views of Thebe
Original Caption Released with Image These two images of the Jovian moon Thebe were taken by Galileo's solid state imaging system in November 1996 and June 1997, respectively. North is approximately up in both cases. Thebe, whose longest dimension is approximately 116 kilometers (72 miles) across, is tidally locked so that the same side of the satellite always points towards Jupiter, similar to how the nearside of our own Moon always points toward Earth. In such a tidally locked state, one side of Thebe always points in the direction in which Thebe moves as it orbits about Jupiter. This is called the "leading side" of the moon and is shown at the left. The image on the right emphasizes the side of Thebe that faces away from Jupiter (the "anti-Jupiter" side). Note that there appear to be at least three or four very large impact craters on the satellite--very large in the sense that each of these craters is roughly comparable in size to the radius of Thebe. 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
Changes on Io between Voyage …
PIA01070
Jupiter
Solid-State Imaging
Title Changes on Io between Voyager 1 and Galileo's second orbit around an unnamed vent North of Prometheus
Original Caption Released with Image Detail of changes around a probable vent about 650 kilometers north of Prometheus on Jupiter's moon Io as seen in images obtained by the Voyager 1 spacecraft in April 1979 (left) and the imaging system aboard NASA's Galileo spacecraft on September 7th, 1996 (right). The re-arranging of dark and light radial surface patterns may be a result of plume fallout. North is to the top of both images which are approximately 400 kilometers square. 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
Dynamics of Jupiter's Great …
PIA01083
Sol (our sun)
Solid-State Imaging
Title Dynamics of Jupiter's Great Red Spot in the near-infrared
Original Caption Released with Image Dynamics of Jupiter's Great Red Spot in the NIR filter (756 nm) of the Galileo imaging system. Each of the three frames is a mosaic of six images that have been map-projected to a uniform grid of latitude and longitude. North is at the top. There is a nine-hour separation between the first two frames and seventy minutes between the next two. All of the images were taken on June 26, 1996. The Red Spot is 20,000 km long and has been followed by observers on Earth since the telescope was invented 300 years ago. It is a huge storm made visible by variations in the composition of the cloud particles and the amount of cloud cover. Winds in the outer part of the Red Spot reach 250 mph while the center remains quiescent. These Galileo data will help scientists understand what drives this storm and why it persists for so many years. 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
Highest Resolution Picture o …
This image, acquired by NASA …
5/31/00
Date 5/31/00
Description This image, acquired by NASA's Galileo spacecraft on February 22, 2000, is the highest resolution image ever taken of Io. The resolution is 5.2 meters (18 feet) per picture element. Galileo viewed the surface obliquely, tilted 72 degrees from straight overhead. Illumination is from the lower right, but the topographic shading is difficult to see because of the strong contrasts in brightness of the surface materials. The bright areas are generally higher in elevation than adjacent dark areas. The surface appears to have been eroded by an unknown process, in places exposing layers of bright and dark material. Evaporation of solid ice may also play a role in separating the bright and dark materials. North is toward the upper right. Also shown is a version of this image processed to give a bird's- eye view over the terrain. This image maps out the true distribution of bright and dark surface materials. The Jet Propulsion Laboratory, Pasadena, CA manages the mission for NASA's Office of Space Science, Washington, DC. JPL is a division of the California Institute of Technology, Pasadena, CA. This image and other images and data received from Galileo are posted 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://galileo.jpl.nasa.gov/images/io/ioimages.html . #####
Caldera-like depression on G …
The shallow, scalloped depre …
12/16/00
Date 12/16/00
Description The shallow, scalloped depression in the center of this picture from NASA's Galileo spacecraft is a caldera-like feature 5 to 20 kilometers (3 to 12 miles) wide on Jupiter's largest moon, Ganymede. Calderas are surface depressions formed by collapse above a subsurface concentration of molten material. Some shallow depressions in bright, smooth areas of Ganymede have some overall similarities to calderas on Earth and on Jupiter's moon Io. On Ganymede, caldera-like depressions may serve as sources of bright, volcanic flows of liquid water and slush, an idea supported by a Ganymede photo obtained by Galileo during its seventh orbit and available at http://photojournal.jpl.nasa.gov/cgi- bin/PIAGenCatalogPage.pl?PIA01614 . In the more recent image here, from Galileo's 28th orbit, a tall scarp marks the western boundary of a caldera-like feature. The western scarp is aligned similarly to older tectonic grooves visible in the image, suggesting the feature has collapsed along older lines of weakness. The interior is mottled in appearance, yet smooth compared to most of Ganymede's bright terrain seen at high resolution. The eastern boundary of the caldera-like feature is cut by younger, grooved terrain. Small impact craters pepper the scene, but the lack of a raised rim argues against an impact origin for the caldera-like feature itself. Instead, water-rich icy lava may have once flowed out of it toward the east. If so, later tectonism could have erased any telltale evidence of volcanic flow fronts. Direct evidence for icy volcanism on Ganymede continues to be elusive. North is to the top of the picture and the Sun illuminates the surface from the left. The image, centered at -24 degrees latitude and 318 degrees longitude, covers an area approximately 162 by 119 kilometers (101 by 74 miles). The resolution is 43 meters (141 feet) per picture element. This image and other images and data received from Galileo are posted on the Galileo mission home page at http://www.jpl.nasa.gov/galileo . Background information and educational context for the images can be found at http://www.jpl.nasa.gov/galileo/sepo . The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the Galileo mission for NASA's Office of Space Science, Washington, D.C. This image was produced by Brown University, Providence, R.I., http://www.planetary.brown.edu/ . # # # # #
Voyager-to-Galileo Changes, …
PIA01063
Jupiter
Solid-State Imaging
Title Voyager-to-Galileo Changes, Io's Anti-Jove Hemisphere
Original Caption Released with Image Shown here is a comparison of a Galileo color image (right) of Jupiter's moon Io, with a Voyager mosaic (left) reprojected to the same geometry as the Galileo image. The image on the right was obtained by the Galileo spacecraft's imaging camera on September 7th, 1996, the mosaic on the left was obtained by the Voyager spacecraft in 1979. Color is synthesized from green and violet filters only in both cases, as these are the only two filters that are reasonably similar between Voyager and Galileo. Many surface changes can be seen due to volcanic activity from 1979 to 1996. North is to the top of both frames. Galileo was about 487,000 kilometers (302,000 miles) from Io on September 7, 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 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
Caldera in Sippar Sulcus, Ga …
PIA03217
Jupiter
Solid-State Imaging
Title Caldera in Sippar Sulcus, Ganymede
Original Caption Released with Image An irregularly shaped caldera, or pit, within the bright swath called Sippar Sulcus on Jupiter's moon Ganymede dominates this image taken by NASA's Galileo spacecraft. The high-standing interior of the caldera is interpreted as evidence of the flow of a viscous material. Elevation modeling indicates the height of the westernmost caldera floor material (arrow) is comparable to adjacent grooved material but decreases towards the east (right), where it is similar to nearby, lower-lying smooth terrain. The smooth terrain, generally lacking grooves or stripes, extends across the upper half of the image and crosscuts a similar but grooved band at the lower right. Analysis of such high-resolution images in combination with estimates of the features' relative elevations is helping scientists interpret the roles of volcanism and tectonics in creating the bright terrain on Ganymede. This image was prepared by the Lunar and Planetary Institute, Houston, and included in a report by Dr. Paul Schenk et al. in the March 1, 2001, edition of the journal Nature. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the Galileo mission for NASA's Office of Space Science, Washington, D.C. Images and data received from Galileo are posted on the Galileo mission home page at http://www.jpl.nasa.gov/galileo. Background information and educational context for the images can be found at http://www.jpl.nasa.gov/galileo/sepo.
Ridges and Troughs in Sippar …
PIA03216
Jupiter
Solid-State Imaging
Title Ridges and Troughs in Sippar Sulcus, Ganymede
Original Caption Released with Image Embayment of ridges and troughs in a portion of the Sippar Sulcus area of Jupiter's moon Ganymede in this image from NASA's Galileo spacecraft is interpreted as evidence that the low-lying area was filled in by flooding with low-viscosity material, such as water or water-ice slush lavas. Bays of the material appeared to have formed in troughs (indicated by arrows) between the ridges. The smallest features visible are about 180 meters (590 feet) across. Analysis of such high-resolution images in combination with estimates of the features' relative elevations is helping scientists interpret the roles of volcanism and tectonics in creating the bright terrain on Ganymede. This image was prepared by the Lunar and Planetary Institute, Houston, and included in a report by Dr. Paul Schenk et al. in the March 1, 2001, edition of the journal Nature. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the Galileo mission for NASA's Office of Space Science, Washington, D.C. Images and data received from Galileo are posted on the Galileo mission home page at http://www.jpl.nasa.gov/galileo. Background information and educational context for the images can be found at http://www.jpl.nasa.gov/galileo/sepo .
Galileo PPR temperature maps …
PIA02524
Jupiter
Title Galileo PPR temperature maps of Loki in October 1999
Original Caption Released with Image Like a terrestrial weather map, this map made by the photopolarimeter-radiometer onboard NASA's Galileo spacecraft shows how temperatures vary across the surface of Jupiter's moon Io. However, in this case the temperatures are due to volcanic activity, not weather. The maps show Io's most powerful volcano, Loki, which was in the throes of one of its periodic bright eruptions when the map was made during Galileo's close flyby of Io on October. The background to the temperature map is a Galileo image of Loki taken earlier in the Galileo mission. Loki's most prominent feature is the huge horseshoe-shaped dark caldera, 200 kilometers (120 miles) across. These observations reveal that most of the lava lake is at a remarkably uniform temperature, about -23 degrees C (-9 degrees F). This is chilly by Earth standards, but on Io, where most of the surface is colder than -145 degrees C (-230 degrees F), enormous amounts of volcanic heat are required to keep such a large area at this temperature. The uniform temperature, which was also seen by Galileo's Near Infrared Mapping Spectrometer, could be due to a uniformly thick frozen crust over a lake of molten lava, or to a series of old lava flows that have been cooling down for a year or two since they erupted. The southwestern corner of the caldera is much hotter the highest resolution photopolarimeter-radiometer observation shows peak temperatures of at least 126 degrees C (260 F). It is likely that this is the site of the new eruption that began in September, and that fresh lava erupting there will eventually spill out from this region to warm up the parts of the caldera to the east and north. The Jet Propulsion Laboratory, Pasadena, CA manages the Galileo mission for NASA's Office of Space Science, Washington, DC. JPL is a division of the California Institute of Technology, Pasadena, CA. This image and other images and data received from Galileo are posted 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 ].
Secondary Craters on Ganymed …
PIA01061
Jupiter
Solid-State Imaging
Title Secondary Craters on Ganymede
Original Caption Released with Image Two large, ancient impact craters, known as palimpsests, have modified this area of dark terrain on Jupiter's moon Ganymede. In lower resolution images from the Voyager mission in 1979, it was observed that the diffuse edge of a large, circular bright feature cut through this area. This image was obtained by the Solid State Imaging (CCD) system aboard NASA's Galileo spacecraft, on September 6, 1996, at a higher resolution of 190 meters (623 feet) per picture element (pixel). North is to the top. The diffuse margin of this palimpsest is noticeable only as a gradual increase in the area covered by bright hummocks toward the western edge of the image. A more recent palimpsest-forming impact to the south has peppered this area with chains and clusters of secondary craters ranging from 5.7 to 1.2 kilometers (3.5 to 0.7 miles) in diameter. The image covers an area of 73 by 65 kilometers (45 by 40 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
Grooves and Craters on Ganym …
PIA01059
Jupiter
Solid-State Imaging
Title Grooves and Craters on Ganymede
Original Caption Released with Image Grooved terrain in this area of Nippur Sulcus on Jupiter's moon Ganymede is composed of ridges and troughs spaced 1 to 2 kilometers (0.6 to 1.2 miles) apart. North is to the top. A few broad (4 to 5 kilometer (2.5 to 3.1 mile) wide) ridges such as those in the northeast and southwest corners have smaller ridges on top of them. A 12 kilometer (7 mile) diameter impact crater is superimposed on these ridges. A dark ring at the base of the crater walls may be due to a collection of dark material at the base of the steep slopes. The image is 49 by 41 kilometers (30 by 25 miles) with a resolution of 200 meters (656 feet) per picture element (pixel). This image was obtained on September 6, 1996 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
Ganymede Groove Lanes
PIA01056
Jupiter
Solid-State Imaging
Title Ganymede Groove Lanes
Original Caption Released with Image An ancient dark terrain surface is cut by orthogonal sets of fractures on Jupiter's moon Ganymede. Subdued pits visible on unbroken blocks are the remnants of impact craters which have degraded with time. Across the top of the image, a line of these subdued pits may have been a chain of craters which are now cut apart by the northwest to southeast trending fractures. North is to the top. Younger craters appear as bright circles. The fractures in this image range from less than 100 meters (328 feet) to over a kilometer (0.62 miles) in width. They display bright walls where cleaner ice may be exposed, and deposits of dark material fill their floors. This 27 by 22 kilometer (17 by 14 mile) image of northern Marius Regio was obtained on September 6, 1996 by NASA's Galileo spacecraft at a resolution of 85 meters (278 feet) per picture element (pixel). The Jet Propulsion Laboratory, Pasadena, CA manages the Galileo mission for NASA's Office of Space Science, Washington, DC. JPL is an operating division of California Institute of Technology (Caltech). This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo mission home page at URL http://galileo.jpl.nasa.gov. Background information and educational context for the images can be found at URL http://www.jpl.nasa.gov/galileo/sepo
Fractures in Transitional Te …
PIA01062
Jupiter
Solid-State Imaging
Title Fractures in Transitional Terrain on Ganymede
Original Caption Released with Image This area of dark terrain on Jupiter's moon Ganymede lies near a transitional area between dark and bright terrain. The dark surface is cut by a pervasive network of fractures, which range in width from the limit of resolution up to 2.2 kilometers (1.4 miles). Bright material is exposed in the walls of the chasms, and dark material fills the troughs. The impurities which darken the ice on the surface of dark terrain may be only a thin veneer over a brighter ice crust. Over time, these materials may be shed down steep slopes, where they collect in low areas. The image is 68 by 54 kilometers (42 by 33 miles), and has a resolution of 190 meters (623 feet) per picture element (pixel). North is to the top. This image was obtained on September 6, 1996 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
Global View of Io (Natural a …
PIA01064
Jupiter
Solid-State Imaging
Title Global View of Io (Natural and False/Enhanced Color)
Original Caption Released with Image Global view of Jupiter's volcanic moon Io obtained on 07 September, 1996 Universal Time using the near-infrared, green, and violet filters of the Solid State Imaging system aboard NASA/JPL's Galileo spacecraft. The top disk is intended to show the satellite in natural color, similar to what the human eye would see (but colors will vary with display devices), while the bottom disk shows enhanced color to highlight surface details. The reddest and blackest areas are closely associated with active volcanic regions and recent surface deposits. Io was imaged here against the clouds of Jupiter. North is to the top of the frames. The finest details that can discerned in these frames are about 4.9 km across. 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
Fractured Craters on Ganymed …
PIA01089
Jupiter
Solid-State Imaging
Title Fractured Craters on Ganymede
Original Caption Released with Image Two highly fractured craters are visible in this high resolution image of Jupiter's moon, Ganymede. NASA's Galileo spacecraft imaged this region as it passed Ganymede during its second orbit through the Jovian system. North is to the top of the picture and the sun illuminates the surface from the southeast. The two craters in the center of the image lie in the ancient dark terrain of Marius Regio, at 40 degrees latitude and 201 degrees longitude, at the border of a region of bright grooved terrain known as Byblus Sulcus (the eastern portion of which is visible on the left of this image). Pervasive fracturing has occurred in this area that has completely disrupted these craters and destroyed their southern and western walls. Such intense fracturing has occurred over much of Ganymede's surface and has commonly destroyed older features. The image covers an area approximately 26 kilometers (16 miles) by 18 kilometers (11 miles) across at a resolution of 86 meters (287 feet) per picture element. The image was taken on September 6, 1996 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.
Motion in Jupiter's Atmosphe …
PIA01230
Sol (our sun)
Solid-State Imaging
Title Motion in Jupiter's Atmospheric Vortices (Near-infrared filters)
Original Caption Released with Image Two frame "movie" of a pair of vortices in Jupiter's southern hemisphere. The two frames are separated by ten hours. The right oval is rotating counterclockwise, like other anticyclonic bright vortices in Jupiter's atmosphere. The left vortex is a cyclonic (clockwise) vortex. The differences between them (their brightness, their symmetry, and their behavior) are clues to how Jupiter's atmosphere works. The frames span about fifteen degrees in latitude and longitude and are centered at 141 degrees west longitude and 36 degrees south planetocentric latitude. Both vortices are about 3500 kilometers in diameter in the north-south direction. The images were taken in near infrared light at 756 nanometers and show clouds that are at a pressure level of about 1 bar in Jupiter's atmosphere. North is at the top. The smallest resolved features are tens of kilometers in size. These images were taken on May 7, 1997, at a range of 1.5 million kilometers by the Solid State Imaging 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
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
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
Europa--Ice Rafting
A small region of the thin, …
12/16/97
Date 12/16/97
Description A small region of the thin, disrupted ice crust in the Conamara region of Jupiter's moon Europa shows the interplay of surface color with ice structures in this image produced with data from NASA's Galileo spacecraft camera. The white and blue colors outline areas that have been blanketed by a fine dust of ice particles ejected when an explosive impact created the large crater Pwyll (26 kilometers or 16 miles in diameter) located some 1,000 kilometers (about 620 miles) to the south. Also visible are a few small craters of less than 500 meters or 547 yards in diameter that were probably formed at the same when the impact likely threw out large, intact, blocks of around the area. 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 seen in large areas elsewhere on Europa's surface. 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 latitude and 86.5 degrees south longitude, covers an area approximately 70 by 30 kilometers (44 by 19 miles), and combines data taken by the Galileo Solid State Imaging (CCD) system during three of the spacecraft's 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 acquired on Feb. 20, 1997 at a resolution of 54 meters (59 yards) per picture element and at a range of 5,340 kilometers (3,320 miles). The Jet Propulsion Laboratory, Pasadena, CA manages the Galileo 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 mission home page at URL http://www.jpl.nasa.gov/galileo. Background information and educational context for the images can be found at URL http://www.jpl.nasa.gov/galileo/sepo #####
High-Resolution Europa Mosai …
This mosaic of images from N …
12/16/97
Date 12/16/97
Description This mosaic of images from NASA's Galileo spacecraft camera shows some of the highest resolution images of Jupiter's moon Europa ever acquired. The hundreds of ridges that cut across each other indicate multiple episodes of ridge formation either by volcanic or tectonic activity within the ice. The images were taken on Nov. 6, 1997 from a range of about 3,250 kilometers (about 1,990 miles). North is to the top of the image and the Sun illuminates the scene from the left. 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 (in the left-center and lower left corner of the mosaic) may be related to the chaotic areas of iceberg-like features seen in earlier Galileo images of Europa. The mosaic, centered at 35.4 degrees north latitude and 86.8 degrees west longitude, covers an area of 66 by 55 kilometers (108 by 90 miles). The smallest distinguishable features in the image are about 68 meters (223 feet) across. The Jet Propulsion Laboratory, Pasadena, CA manages the Galileo 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 mission home page at URL http://www.jpl.nasa.gov/galileo. Background information and educational context for the images can be found at URL http://www.jpl.nasa.gov/galileo/sepo #####
Regional Mosaic--Europa Chao …
This mosaic of images taken …
12/16/97
Date 12/16/97
Description This mosaic of images taken by NASA's Galileo spacecraft camera shows a region of Jupiter's moon Europa that is characterized by dark and splotchy-looking terrain -- evidence of some of the most recent geologic activity on Europa. The mottled appearance results from chaotic areas where the bright, icy crust has broken apart to expose a darker material underneath. North is to the top of the image, and the Sun illuminates the scene from the right. The images were taken on Nov. 6. The smooth gray band at the lower part of image represents a zone where the Europan crust has been fractured, separated, and filled in with material from the interior. The chaotic terrain and the gray band show that Europa has been subjected to intense geological deformation. The mosaic is centered at 2.9 degrees south latitude and 234.1 degrees west longitude and covers an area of 261 kilometers by 168 kilometers (159 miles by 102 miles). The smallest distinguishable features in the image are about 229 meters (751 feet) across. These images were obtained on Nov. 6, 1997, when the Galileo spacecraft was approximately 21,700 kilometers (about 13,240 miles) from Europa. The Jet Propulsion Laboratory, Pasadena, CA manages the Galileo 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 mission home page at URL http://www.jpl.nasa.gov/galileo. Background information and educational context for the images can be found at URL http://www.jpl.nasa.gov/galileo/sepo #####
Highest resolution of lava f …
Lava flows similar to those …
4/19/00
Date 4/19/00
Description Lava flows similar to those found in Hawaii are seen in the black and white image at top, taken by NASA's Galileo spacecraft. It is one of the highest resolution images (7 meters or 23 feet per picture element) ever obtained of Jupiter's volcanic moon Io. The two horizontal black stripes are places where data were lost during transmission to Earth. The image shows the textures of lava flows on the floor of the caldera Chaac, which is shown in false color at lower resolution (185 meters or 607 feet per pixel element) in the bottom image. Calderas are depressions caused by collapse during volcanic eruptions. The one shown here is approximately 100 kilometers (63 miles) long and 30 kilometers (19 miles) across. Using shadow lengths from the new high-resolution observations, the northeastern (upper right) scarp, or line of cliffs, has been estimated to be 2.8 kilometers (9200 feet) high. The lava flows are similar in texture to lava flows within the caldera at Hawaii's Kilauea volcano. This suggests that the floor of Chaac has been covered by a combination of lava flows and lava lakes. The light-colored material surrounding the caldera may be composed of sulfur-dioxide frost or some other sulfur-rich material on the surface of Io. Galileo scientists believe that the greenish color on the caldera floor is a form of contaminated sulfur created when sulfur-rich material escaping from volcanic vents reacts chemically with warm lava flows. The high- resolution view shows numerous lava flows. The darkest flows are thought to be the most recent because they have not been covered by the sulfurous materials which coat most of Io's surface. The top image was acquired by Galileo on February 22, 2000. It was taken at a distance of 600 kilometers (370 miles) and is centered at 11.9 degrees north latitude and 157.6 degrees west longitude. North is to the top, and the Sun illuminates the surface from the right. The color image was created by combining a black and white image taken on February 22, 2000 at a distance of 18,800 kilometers (11,700 miles) from Io with lower-resolution (1.3 kilometers or 0.81 miles per picture element) color images taken on July 3, 1999 at a distance of 130,000 kilometers (81,000 miles). The image is centered at 11.6 degrees north latitude and 157.7 degrees west longitude. North is to the top and the Sun illuminates the surface from the left. The Jet Propulsion Laboratory, Pasadena, CA manages the Galileo mission for NASA's Office of Space Science, Washington, DC. JPL is a division of the California Institute of Technology, Pasadena, CA. This image and other images and data received from Galileo are posted 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://galileo.jpl.nasa.gov/images/io/ioimages.html . #####
Terrain near Io's south pole
Volcanic calderas, lava flow …
4/19/00
Date 4/19/00
Description Volcanic calderas, lava flows and cliffs are seen in this false color image of a region near the south pole of Jupiter's volcanic moon Io. It was created by combining a black and white image taken by NASA's Galileo spacecraft on February 22, 2000 with lower resolution color images taken by Galileo on July 3, 1999. The three black spots (top center and middle left) are small volcanic calderas about 10-20 kilometers (6-12 miles) in size, which are dark because their floors are covered by recent lava flows. Two of these three calderas are surrounded by diffuse dark material, which may have been thrown out of the calderas by explosive eruptions. The bright, white material is thought to be sulfur-dioxide frost and is concentrated near the cliffs in this image. It may be formed when liquid sulfur dioxide seeps out at the base of mountain scarps, vaporizes into a plume of gas, liquid and solid, and then condenses again on the surface. Part of this process, called sapping, occurs in arid environments on Earth when ground water seeps out at the bases of cliffs. The vaporization and production of plumes is much more dramatic on Io due to the lower gravitational acceleration and especially the very low atmospheric pressure. It may be one of the dominant erosion processes on Io. The mountain at the center left, named Telegonus Mensae, exhibits a number of ridges parallel to its margins. These ridges have been observed on a number of other Ionian mountains and they suggest that as the mountain ages, it is collapsing outward under the influence of gravity. The yellow lava flow at the southern end of the image appears to be fed by a dark channel that connects to a dark caldera. This is a likely candidate for a lava flow composed of sulfur (rather than silicate material). The image is centered at 53.8 degrees south latitude and 117.1 degrees west longitude and north is to the top. The higher resolution image has a resolution of 350 meters (or yards) per picture element and is illuminated from the upper left. It was taken at a range of 34,000 kilometers (21,000 miles). The color images have resolutions of 1.3 kilometers (0.81 miles) per picture element and are illuminated from almost directly behind the spacecraft. They were taken at a distance of about 130,000 kilometers (81,000 miles) by Galileo's onboard camera. The Jet Propulsion Laboratory, Pasadena, CA manages the Galileo mission for NASA's Office of Space Science, Washington, DC. JPL is a division of the California Institute of Technology, Pasadena, CA. This image and other images and data received from Galileo are posted 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://galileo.jpl.nasa.gov/images/io/ioimages.html . #####
Ganymede dark terrain at hig …
Impact craters dominate the …
12/16/00
Date 12/16/00
Description Impact craters dominate the surface down to the smallest features visible on the dark terrain of the Nicholson Regio region of Jupiter's moon Ganymede in this image taken by NASA's Galileo spacecraft. It is the highest resolution view ever obtained of Ganymede's dark terrain. Both the regional-scale image at the bottom and high- resolution image at the top were taken by Galileo during its May 20, 2000, flyby of Ganymede. The latter are the highest resolution images ever obtained of Ganymede's dark terrain, which makes up about one third of Ganymede's surface. Impact cratering is clearly the dominant mechanism of surface modification in this relatively ancient terrain, which is analogous to the cratered highlands of Earth's Moon. Small- scale craters seem to mimic larger-scale craters, as is apparent in the similarities between the high and medium resolution scenes. The bright spots are probably fresh ice-rich ejecta excavated by the most recent impact events. North is to the top of the images and the Sun illuminates the surface from the west. The medium-resolution image, centered at –15 degrees latitude and 337 degrees longitude, covers an area approximately 237 by 130 kilometers (147 by 81 miles) at a resolution of 125 meters (410 feet) per picture element. The high-resolution image is at 28 meters (92 feet) per picture element. This image and other images and data received from Galileo are posted on the Galileo mission home page at http://www.jpl.nasa.gov/galileo . Background information and educational context for the images can be found at http://www.jpl.nasa.gov/galileo/sepo . The Jet Propulsion Laboratory, a division of the California Institute of Technology, in Pasadena, manages the Galileo mission for NASA's Office of Space Science, Washington, D.C. The images were produced by Arizona State University, Tempe, and Brown University, Providence, R.I.. Their websites are at http://europa.la.asu.edu/index.html and http://www.planetary.brown.edu/ . # # # # #
Bright-dark boundary and top …
These images, taken by NASA' …
12/16/00
Date 12/16/00
Description These images, taken by NASA's Galileo spacecraft on its May 20, 2000, flyby of Jupiter's moon Ganymede, illustrate the boundary and different elevations between the dark, ancient terrain of Nicholson Regio (left) and bright, younger terrain of Harpagia Sulcus (right.) The bottom image is a wide view of the boundary, and the top image is an enlargement of the colorized strip. An important goal of Galileo's Ganymede encounter was to understand the nature of the boundary between ancient, dark terrain and younger, bright terrain. The camera was aimed at the boundary to obtain both very high-resolution images (top) and medium-resolution context images (bottom). Color-coded elevations are indicated relative to the average elevation of the sampled area, with high elevation marked in red, and low in blue. Combining the two image mosaics allows scientists to derive a detailed description of the region from the overlap. The data shows that there are approximately 200 meters (about 650 feet) of topographic relief within the bright terrain here, and a deep depression marks the boundary between bright and dark terrains. North is to the top of the pictures. The Sun illuminates the surface from the left. The larger image, centered at –14 degrees latitude and 319 degrees longitude, covers an area approximately 213 by 97 kilometers (132 by 60 miles.) The resolution of the high-resolution image is 20 meters (about 65 feet) per picture element, and the context image is at 121 meters (397 feet) per picture element. The higher resolution image was taken at a range of 2000 kilometers (over 1,200 miles). The Jet Propulsion Laboratory, Pasadena, Calif., manages the Galileo mission for NASA's Office of Space Science, Washington, D.C. JPL is a division of the California Institute of Technology in Pasadena. This image and other images and data received from Galileo are posted on the Galileo mission home page at http://www.jpl.nasa.gov/galileo . The images were produced by the German Aerospace Center (DLR) http://solarsystem.dlr.de/ , and Brown University, http://www.planetary.brown.edu/ . Background information and educational context for the images can be found at http://www.jpl.nasa.gov/galileo/sepo . # # # # #
Not-so-smooth bright terrain …
The highest-resolution image …
12/16/00
Date 12/16/00
Description The highest-resolution images ever obtained of Jupiter's moon Ganymede show that even smooth-looking terrain has been deformed at a fine scale. The high-resolution image taken of the bright Harpagia Sulcus area by NASA's Galileo spacecraft during a May 20, 2000, flyby of Ganymede shows features as small as 16 meters (52 feet). This area was selected for a closer look because, in images taken by NASA's Voyager spacecraft about 20 years earlier, it looked as flat as a hockey rink. It appears smooth even in a medium-resolution Galileo image (at 116 meters or 380 feet per pixel) that is superimposed over a Voyager image in the top portion of this frame. But the closeup shot revealed that, instead of a hockey rink, the area has ups and downs that would be challenging for a cross-country skier. North is to the top of the picture and the Sun illuminates the surface from the left. The medium-resolution image mosaic is centered at -16 degrees latitude and 310 degrees longitude, and covers an area approximately 282 by 144 kilometers (175 by 89 miles). This image and other images and data received from Galileo are posted on the Galileo mission home page at http://www.jpl.nasa.gov/galileo . Background information and educational context for the images can be found at http://www.jpl.nasa.gov/galileo/sepo . The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the Galileo mission for NASA's Office of Space Science, Washington, D.C. This image was produced by DLR (German Aerospace Center), Berlin, and Brown University, Providence, R.I., http://solarsystem.dlr.de/ and http://www.planetary.brown.edu/ . # # # # #
Mosaic and Topographic Image …
Images taken with different …
2/26/01
Date 2/26/01
Description Images taken with different lighting and from different positions by NASA's Galileo spacecraft provide information about the three-dimensional structure of a large mountain named Tohil Mons on Jupiter's moon Io. One of these images is a mosaic combining detailed images that were taken by Galileo on Feb. 22, 2000, with a lower- resolution image of a wider area taken on June 30, 1999. The sharper portion has a resolution of 165 meters (540) feet per picture element. The lower-resolution context image is at 1.3 kilometers (0.8 mile) per picture element. North is to the top of the image. The Sun was almost directly behind the spacecraft, so shadows are negligible. The other image (inset lower left corner) is a topographic representation of what Tohil Mons looks like when seen from the northeast. The topography has been vertically exaggerated. The peak's height is about 6 kilometers, plus or minus 2 kilometers (about 20,000 feet, give or take 6,600 feet). The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the Galileo mission for NASA's Office of Space Science, Washington, D.C. Images and data received from Galileo are posted on the Galileo mission home page at http://www.jpl.nasa.gov/galileo. Background information and educational context for the images can be found at http://www.jpl.nasa.gov/galileo/sepo . # # # # #
Stereo Image of Io's Tohil M …
This stereo image, which app …
2/26/01
Date 2/26/01
Description This stereo image, which appears three-dimensional when viewed through stereo red-blue glasses, was created from data in images taken on Oct. 11, 1999, and on Feb. 22, 2000, by NASA's Galileo spacecraft of a mountain named Tohil Mons on Jupiter's moon Io. It illustrates the shape of the mountain and two nearby volcanic depressions, which are called paterae. North is toward the top of the image. The largest patera, in the upper right, lies along the northeastern margin of the mountain. The stereo observation reveals that the smaller patera with the dark floor is surrounded by mountainous walls. The black lines are areas where data were not acquired. Information about the red-blue glasses needed for seeing this 3-D image properly is available at http://photojournal.jpl.nasa.gov/Help/VendorList.html#Glasses . To the southeast of the peak, many bright lines trending northwest-southeast can be seen. Since the two individual images were taken when the sun was quite high, it was difficult to determine the relationship between the bright material and the topography. The stereo image reveals that the light material is concentrated at the bases of cliffs. This series of cliffs appears step-like, which may indicate layering in Io's crust. By combining several observations in this manner, Galileo scientists are able to study Io's mountains and to learn about their evolution and their relationship to Io's volcanoes. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the Galileo mission for NASA's Office of Space Science, Washington, D.C. Images and data received from Galileo are posted on the Galileo mission home page at http://www.jpl.nasa.gov/galileo. Background information and educational context for the images can be found at http://www.jpl.nasa.gov/galileo/sepo . # # # # #
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 ].
Clouds and Hazes of Jupiter' …
PIA02098
Sol (our sun)
Solid-State Imaging
Title Clouds and Hazes of Jupiter's Southern Hemisphere
Original Caption Released with Image The clouds and hazes of Jupiter's southern hemisphere, in the region between 25 degrees south latitude and the pole, are shown in approximately true color (left mosaic) and in false color (right mosaic). The false color is used to reveal the heights and thicknesses of Jupiter's clouds. The images were taken by NASA's Galileo spacecraft. The clouds visible in these mosaics are being folded and sheared by Jupiter's winds, like cream in a cup of coffee. The upper part of the mosaics sports a pair of vortices, one rotating clockwise (left) and one rotating counterclockwise (right). Each is about 3500 kilometers (2170 miles) in their north-south dimension. North is toward the top of the mosaics. The bright spots near the top edge may be places where new cloud material is forming, perhaps analogous to huge convective storms on Earth, complete with lightning. Near Jupiter's pole, the cloud features become increasingly obscured by a "polar cap" of high-altitude haze thought to form from the chemical byproducts of auroral activity. The left mosaic combines violet (410 nanometers) and near-infrared (756 nanometers) images to create a mosaic similar to how Jupiter would appear to human eyes. The different colors are due to the composition and abundance of trace chemicals in Jupiter's atmosphere. The right mosaic uses Galileo's camera's three near-infrared (beyond the visible range) 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. Galileo's camera is the first to distinguish cloud heights on Jupiter. The mosaics are projected on a spheroid. The smallest resolved features are tens of kilometers in size. The images used were taken on May 7, 1997, at a range of 1.2 million kilometers (746,000 miles) by the Solid State Imaging (SSI) system on NASA's Galileo spacecraft during its eighth orbit of Jupiter. The Jet Propulsion Laboratory, Pasadena, CA manages the Galileo mission for NASA's Office of Space Science, Washington, DC. This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo mission home page at URL http://galileo.jpl.nasa.gov [ http://galileo.jpl.nasa.gov ]. Background information and educational context for the images can be found at URL http://www.jpl.nasa.gov/galileo/sepo [ http://www.jpl.nasa.gov/galileo/sepo ].
Galileo's Last View of Tvash …
PIA03529
Jupiter
Solid-State Imaging
Title Galileo's Last View of Tvashtar, Io
Original Caption Released with Image This mosaic of Tvashtar Catena on Jupiter's moon Io, taken by NASA's Galileo spacecraft on Oct. 16, 2001, completes a series of views depicting changes in the region over a period of nearly two years. A catena is a chain of volcanic craters. Streaks of light and dark deposits that radiate from the central volcanic crater, or "patera," are remnants of a tall plume that was seen erupting in earlier images. This image and the others from November 1999, February 2000 [ http://photojournal.jpl.nasa.gov/catalog/PIA02584 ], December 2000 [ http://photojournal.jpl.nasa.gov/catalog/PIA02588 ], and August 2001 [ http://photojournal.jpl.nasa.gov/catalog/PIA02592 ] were all taken to study aspects of this ever-changing, extremely active volcanic field. Tvashtar is pictured here just 10 months after both the Galileo and Cassini spacecraft observed the eruption of a giant plume of volcanic gas emanating from it. The plume rose 385 kilometers (239 miles) high and blanketed terrain as far as 700 kilometers (435 miles) from its center. Tvashtar has erupted in a variety of styles over the course of almost two years: (1) a lava curtain [ http://photojournal.jpl.nasa.gov/catalog/PIA02519 ] 50 kilometers (30 miles) long in the center patera, (2) a giant lava flow or lava lake eruption [ http://photojournal.jpl.nasa.gov/catalog/PIA02550 ] in the giant patera at far left, and (3) the large plume eruption [ http://photojournal.jpl.nasa.gov/catalog/PIA02588 ]. Therefore Galileo scientists expected that the lava flow margins or patera boundaries within Tvashtar would have changed drastically. However, the series of observations revealed little modification of this sort, suggesting that the intense eruptions at Tvashtar are confined by the local topography. North is to the top of the mosaic, which is approximately 300 kilometers(186 miles) across and has a resolution of 200 meters (656 feet) per picture element. 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 athttp://galileo.jpl.nasa.gov [ http://galileo.jpl.nasa.gov ]. Background information and educationalcontext for the images can be found at http://galileo.jpl.nasa.gov/gallery/io.cfm [ http://galileo.jpl.nasa.gov/gallery/io.cfm ].
Galileo Takes a Close-up Loo …
PIA02568
Jupiter
Solid-State Imaging
Title Galileo Takes a Close-up Look at Prometheus
Original Caption Released with Image This high-resolution mosaic of images taken by NASA's Galileo spacecraft shows lava flows, bright streaks, and ridged plains at the northern margin of the lava flow field at the volcanic center Prometheus on Jupiter's moon Io. The images, taken during a flyby of Io on February 22, 2000, have a resolution of 12 meters(39 feet) per picture element. The lava is erupting from a fissure about 40 kilometers (25 miles) east(right) of the edge of this mosaic, and the 100 kilometer (62 mile) tall Prometheus plume is erupting from somewhere near the western end of this mosaic. This mosaic was acquired to search for and image the plume vent or vents. We expected to see a small crater surrounded by radial streaks, but no such central vent can be seen in these or other images. Instead, we see bright streaks along the margins of the lava. The darkest areas are warm lava flows. Warm lava is dark because it is either too hot or too recent for significant amounts of sulfur-dioxide frost or snow from the plume to have condensed onto it. The blow-up shows two bright dots where hot lava is breaking out of the edge of one of the dark lava flows. The bright, ridged plains to the north of the lava are probably rich in sulfur dioxide. The formation mechanism for the ridges is unclear. The very bright streaks radiating from the area where the lava flows overrun the field are where the hot lava recently vaporized the sulfur dioxide, which then coated the lava-facing sides of the ridges. The Prometheus plume has been seen by both the Voyager and Galileo spacecraft whenever the viewing geometry has been favorable. While the morphology of the plume has been nearly constant, the plume's position jumped about 80 kilometers (50 miles) between the Voyager observations in the 1970s and the Galileo observations since 1995. The lava flow field has migrated a similar distance. Galileo scientists are currently investigating whether fresh lava breakouts overrunning plains rich in sulfur dioxide can help explain the plume observations. The Jet Propulsion Laboratory, Pasadena, Calif., manages the mission for NASA's Office of Space Science, Washington, DC. JPL is a division of the California Institute of Technology in Pasadena. This image and other images and data received from Galileo are posted on the Galileo mission home page athttp://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 ].
Arbela Sulcus flyover movie
PIA02583
Jupiter
Solid-State Imaging
Title Arbela Sulcus flyover movie
Original Caption Released with Image A simulated flyover of an area on Jupiter's largest moon, Ganymede, based on images taken by NASA's Galileo spacecraft, takes the viewer over rugged, ancient terrain that is interrupted by a bright icy swath of more recent surfacing. The dark, rugged terrain in the foreground at the start is part of Nicholson Regio. Parts of the dark terrain are heavily cratered, testifying to their ancient age, but other parts have been deformed into deep grooves by stretching and faulting. A swath called Arbela Sulcus slices through the rough terrain and appears as a dramatically different type of surface, brighter and smoother, between two parts of Nicholson Regio. High-resolution images of Arbela Sulcus obtained by Galileo suggest it may be the result of crustal spreading, similar to a process evident on the surface of Europa, another of Jupiter's moons. The simulated fly-over in Quicktime format was constructed by combining images obtained during the seventh and 28th orbits of Jupiter by Galileo, on May 7, 1997, and May 20, 2000. Stereo images were used to derive the topography of the area, then regional-scale and high-resolution images from the more recent orbit were draped over the topographic model. The flyover region is centered near -14 degrees latitude and 347degrees longitude. The resolution of the image data is 35 and 130 meters(114 and 426 feet) per picture element, and the vertical exaggeration is three times. Images and data received from Galileo are posted on the Galileo mission home page at http://www.jpl.nasa.gov/galileo [ http://www.jpl.nasa.gov/galileo ]. Background information and educational context for the images can be found athttp://www.jpl.nasa.gov/galileo/sepo [ http://www.jpl.nasa.gov/galileo/sepo ]. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the Galileo mission for NASA's Office of Space Science, Washington, D.C. This image was produced by DLR (German Aerospace Center), Berlin, and Brown University, Providence, R.I., http://solarsystem.dlr.de/ [ http://solarsystem.dlr.de/ ] andhttp://www.planetary.brown.edu/ [ http://www.planetary.brown.edu/ ].
Io's Tvashtar Area in Infrar …
PIA02594
Jupiter
Near Infrared Mapping Spectr …
Title Io's Tvashtar Area in Infrared: Multiple Lava Flows
Original Caption Released with Image New and older lava flows clustered in the Tvashtar region of Jupiter's moon Io appear as hot spots in a temperature map from NASA's Galileo spacecraft. The multiple hot spots indicate continuing shifts in the location of Tvashtar's eruptions since the region's volcanic activity was first seen in December 1999. The temperature map (top) uses infrared observations made during Galileo's Aug. 6, 2001, flyby of Io. It is shown using landmarks from a February 2000 visible-light image (bottom) that Galileo's camera recorded of the Tvashtar area of bowl-like depressions in Io's northern hemisphere. The temperature map comes from Galileo's near-infrared mapping spectrometer. Tvashtar has been a very active region since December 1999, when Galileo detected a major eruption from the location marked A (See insert image below). The eruption from A was interpreted as a row of lava fountains. When Galileo flew by Io again in February 2000, the eruption had shifted to the location marked B, where a lava flow shaped like a dolphin's tail is seen. The temperature map shows that volcanic activity is present at many locations in this region. The highest temperatures are found in the three locations marked x, where new lavas may have recently come to the surface. Temperatures (in Kelvin) displayed in the color bar are lower limits. (The range in Fahrenheit is from 460 degrees below zero to 530 degrees above zero.) Each picture element averages the characteristics of an area about 2 kilometers (1.2 miles) across, smaller patches may be hundreds of degrees higher. The Galileo camera did not obtain a visible-light image of the Tvashtar region during the August 2001 flyby. Based on the locations of the hottest materials detected by Galileo's near-infrared mapping spectrometer, volcanologists expect that significant surface changes have occurred.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 ].
Io's Tvashtar Area in Infrar …
PIA02594
Jupiter
Near Infrared Mapping Spectr …
Title Io's Tvashtar Area in Infrared: Multiple Lava Flows
Original Caption Released with Image New and older lava flows clustered in the Tvashtar region of Jupiter's moon Io appear as hot spots in a temperature map from NASA's Galileo spacecraft. The multiple hot spots indicate continuing shifts in the location of Tvashtar's eruptions since the region's volcanic activity was first seen in December 1999. The temperature map (top) uses infrared observations made during Galileo's Aug. 6, 2001, flyby of Io. It is shown using landmarks from a February 2000 visible-light image (bottom) that Galileo's camera recorded of the Tvashtar area of bowl-like depressions in Io's northern hemisphere. The temperature map comes from Galileo's near-infrared mapping spectrometer. Tvashtar has been a very active region since December 1999, when Galileo detected a major eruption from the location marked A (See insert image below). The eruption from A was interpreted as a row of lava fountains. When Galileo flew by Io again in February 2000, the eruption had shifted to the location marked B, where a lava flow shaped like a dolphin's tail is seen. The temperature map shows that volcanic activity is present at many locations in this region. The highest temperatures are found in the three locations marked x, where new lavas may have recently come to the surface. Temperatures (in Kelvin) displayed in the color bar are lower limits. (The range in Fahrenheit is from 460 degrees below zero to 530 degrees above zero.) Each picture element averages the characteristics of an area about 2 kilometers (1.2 miles) across, smaller patches may be hundreds of degrees higher. The Galileo camera did not obtain a visible-light image of the Tvashtar region during the August 2001 flyby. Based on the locations of the hottest materials detected by Galileo's near-infrared mapping spectrometer, volcanologists expect that significant surface changes have occurred.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 ].
Io's Pele Glowing in the Dar …
PIA02596
Jupiter
Solid-State Imaging
Title Io's Pele Glowing in the Dark
Original Caption Released with Image In a high-resolution view from NASA's Galileo spacecraft, the Pele hot spot on Jupiter's moon Io shows a complex pattern of areas glowing in the dark, including areas likely to be fresh overturning of a lava lake's crust. Hundreds of hot spots have been observed on Io, the most volcanic world in the solar system. Most previous observations have been at very low resolution. This false-color nighttime image of the Pele hot spot, acquired during Galileo's close flyby of Io in October 2001, reveals details down to 60 meters (200 feet) in length. Red indicates the most intense combination of temperature and area, blue indicates cooler materials or smaller patches of hot materials. Scientists believe the Pele hot spot has a lava lake inside a volcanic crater or caldera. The series of bright spots seen here may correspond to the edge of the caldera, where cooled crust of the lava lake is breaking up against the wall and hotter lava appears from underneath. (That pattern is seen in a lava lake in Hawaii). Alternatively, they could be fractures in the crust. Galileo acquired similar observations [ http://photojournal.jpl.nasa.gov/catalog/PIA02511 ] in October 1999 and February 2000, but the newest images are the first to show the larger bright areas seen on the right side of the image. These probably correspond to regions of vigorous overturning of the crust. Galileo acquired several nighttime images of Pele in October 2001. These may enable measurements of temperature and perhaps detection of short-term changes in the exposures of hot lava. Preliminary calculations indicate the lava temperature is about 1,400 degrees Kelvin (2,060 degrees Fahrenheit) at one location, which would be similar to the temperatures of lava erupted at Kilauea in Hawaii. North is the top of the picture. The image is centered at 18.7 degrees south latitude and 255.5 degrees west longitude. Galileo's camera took it from a distance of about 6,000 kilometers (3,700 miles) away. 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 ].
Caldera-like depression on G …
PIA02580
Jupiter
Solid-State Imaging
Title Caldera-like depression on Ganymede
Original Caption Released with Image The shallow, scalloped depression in the center of this picture from NASA's Galileo spacecraft is a caldera-like feature 5 to 20 kilometers(3 to 12 miles) wide on Jupiter's largest moon, Ganymede. Calderas are surface depressions formed by collapse above a subsurface concentration of molten material. Some shallow depressions in bright, smooth areas of Ganymede have some overall similarities to calderas on Earth and on Jupiter's moon Io. On Ganymede, caldera-like depressions may serve as sources of bright, volcanic flows of liquid water and slush, an idea supported by a Ganymede photo obtained by Galileo during its seventh orbit and available at PIA01614 [ http://photojournal.jpl.nasa.gov/catalog/PIA01614 ]. In the more recent image here, from Galileo's 28th orbit, a tall scarp marks the western boundary of a caldera-like feature. The western scarp is aligned similarly to older tectonic grooves visible in the image, suggesting the feature has collapsed along older lines of weakness. The interior is mottled in appearance, yet smooth compared to most of Ganymede's bright terrain seen at high resolution. The eastern boundary of the caldera-like feature is cut by younger, grooved terrain. Small impact craters pepper the scene, but the lack of a raised rim argues against an impact origin for the caldera-like feature itself. Instead, water-rich icy lava may have once flowed out of it toward the east. If so, later tectonism could have erased any telltale evidence of volcanic flow fronts. Direct evidence for icy volcanism on Ganymede continues to be elusive. North is to the top of the picture and the Sun illuminates the surface from the left. The image, centered at -24 degrees latitude and 318degrees longitude, covers an area approximately 162 by 119 kilometers(101 by 74 miles). The resolution is 43 meters (141 feet) per picture element. This image and other images and data received from Galileo are posted on the Galileo mission home page at http://www.jpl.nasa.gov/galileo [ http://www.jpl.nasa.gov/galileo ]. Background information and educational context for the images can be found at http://www.jpl.nasa.gov/galileo/sepo [ http://www.jpl.nasa.gov/galileo/sepo ]. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the Galileo mission for NASA's Office of Space Science, Washington, D.C. This image was produced by Brown University, Providence, R.I.,http://www.planetary.brown.edu/ [ http://www.planetary.brown.edu/ ].
Northern Plume and Plume Dep …
PIA02592
Jupiter
Solid-State Imaging
Title Northern Plume and Plume Deposits on Io
Original Caption Released with Image Backlit views (left pair) show a giant volcanic plume as a bulge on the crescent edge of Jupiter's moon Io, and more fully lit views (right pair) reveal rings where sulfur-rich plume material has fallen back to the ground, in images captured by NASA's Galileo spacecraft in early August 2001. Io is the most volcanically active world known. Galileo and NASA's Voyager and Cassini spacecraft have caught several of Io's volcanoes in action lofting plumes of gas and particles high above the large moon's surface. However, none of the plumes seen previously has climbed as high as the one evidenced in three of these pictures. During its Aug. 6, 2001, close encounter with Io, Galileo flew right through a space where a plume from the Tvashtar volcano near Io's north pole had been active when Galileo and Saturn-bound Cassini imaged Io seven months earlier. To see if the Tvashtar plume was still active in August, scientists used Galileo's camera to acquire images when the spacecraft was nearly on the opposite side of Io from the Sun, so that Io appears as a backlit crescent. Tvashtar's plume did not show up, but another one did, rising from a previously undiscovered and still unnamed volcano about 600 kilometers (370 miles) south of Tvashtar. The left two images are color coded to reveal the faint outer plume. The bright inner plume rises about 150 kilometers (90 miles) high, and the top of the faint outer plume can be detected at 500 kilometers (310 miles) above the surface, making this is the largest plume ever detected on Io. A portion of the plume with intermediate brightness extends north of the eruption's source vent. (The vertical lines, bright spots and short streaks in these two images are noise.) One of the more fully illuminated color images of Io (second image from right) reveals a bull's-eye ring of new dark and light materials marking the eruption site. No obvious volcanic center had previously been seen at this location, 41 degrees north latitude and 133 degrees west longitude. The bright material of the new plume deposit overlies the red-ring plume deposit encircling the Tvashtar volcano at 63 degrees north, 123 degrees west. Tvashtar's ring deposit was first seen in Galileo images taken in late December 2000. Another new full-disc color image of Io (far right) reveals yet another new plume deposit near Io's north pole, encircling the Dazhbog Patera volcanic site. This red ring has a diameter of about 1,000 kilometers (620 miles), suggesting a plume height of about 300 kilometers (190 miles). This plume deposit was not present in January 2001, so it is evidence of a new eruption. Io is about the same size as Earth's Moon. All four images have resolutions of 18 to 20 kilometers (11 to 12 miles) per picture element. Unlabeled versions are also available. Click on the thumbnail versions below., Infrared imagery from Galileo or Earth-based telescopes has detected intense hot spots at the sites of all three of these giant plumes. Giant polar plumes represent a class of eruption seen by the Voyager spacecraft in 1979, but not during Galileo's first five years of orbiting Jupiter. Voyager was unable to measure temperatures or other properties of these eruptions, so scientists are pleased Galileo has survived long enough to do so. Galileo reached Jupiter in late 1995. Its original two-year orbital mission has been extended three times to take advantage of the spacecraft's continuing capability to return valuable scientific information about the Jupiter system. 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 ].
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