Galerie de photos de Io, satellite galiléen de la planète Jupiter

<h1>PIA00835: NIMS Observation of Hotspots on Io</h1><div class="PIA00835" lang="en" style="width:800px;text-align:left;margin:auto;background-color:#000;padding:10px;max-height:150px;overflow:auto;">Io has been imaged by the Near Infrared Mapping Spectrometer (NIMS) on Galileo. The image on the right shows for the first time the distribution of volcanic hotspots on the surface of Io, as seen by NIMS. Three of these hotspots are new discoveries, only detectable with the NIMS instrument. This image was taken during the G1 encounter on June 29 1996. The image on the left shows the same view of Io as seen by the Voyager spacecraft in 1979. At least one dozen hotspots have been identified from this NIMS image. Most of the hotspot locations can be matched with volcanic features on the surface of Io, including the vent area of the active Prometheus plume.<p>The Jet Propulsion Laboratory, Pasadena, CA manages the mission for NASA's Office of Space Science, Washington, DC.<p>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.<br /><br /><a href="http://photojournal.jpl.nasa.gov/catalog/PIA00835" onclick="window.open(this.href); return false;" title="Voir l'image PIA00835: NIMS Observation of Hotspots on Io sur le site de la NASA">Voir l'image PIA00835: NIMS Observation of Hotspots on Io sur le site de la NASA.</a></div>
PIA00835: NIMS Observation of Hotspots on Io
<h1>PIA01063: Voyager-to-Galileo Changes, Io's Anti-Jove Hemisphere</h1><div class="PIA01063" lang="en" style="width:800px;text-align:left;margin:auto;background-color:#000;padding:10px;max-height:150px;overflow:auto;">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.<p>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).<p>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 <a href="http://www2.jpl.nasa.gov/galileo/sepo/" target="_blank">http://www.jpl.nasa.gov/galileo/sepo</a>..<br /><br /><a href="http://photojournal.jpl.nasa.gov/catalog/PIA01063" onclick="window.open(this.href); return false;" title="Voir l'image PIA01063: Voyager-to-Galileo Changes, Io's Anti-Jove Hemisphere sur le site de la NASA">Voir l'image PIA01063: Voyager-to-Galileo Changes, Io's Anti-Jove Hemisphere sur le site de la NASA.</a></div>
PIA01063: Voyager-to-Galileo Changes, Io's Anti-Jove Hemisphere
<h1>PIA01064: Global View of Io (Natural and False/Enhanced Color)</h1><div class="PIA01064" lang="en" style="width:635px;text-align:left;margin:auto;background-color:#000;padding:10px;max-height:150px;overflow:auto;">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.<p>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).<p>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 <a href="http://www2.jpl.nasa.gov/galileo/sepo/" target="_blank">http://www.jpl.nasa.gov/galileo/sepo</a>..<br /><br /><a href="http://photojournal.jpl.nasa.gov/catalog/PIA01064" onclick="window.open(this.href); return false;" title="Voir l'image PIA01064: Global View of Io (Natural and False/Enhanced Color) sur le site de la NASA">Voir l'image PIA01064: Global View of Io (Natural and False/Enhanced Color) sur le site de la NASA.</a></div>
PIA01064: Global View of Io (Natural and False/Enhanced Color)
<h1>PIA01065: Lack of visible change around active hotspots on Io</h1><div class="PIA01065" lang="en" style="width:193px;text-align:left;margin:auto;background-color:#000;padding:10px;max-height:150px;overflow:auto;">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.<p>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).<p>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 <a href="http://www2.jpl.nasa.gov/galileo/sepo/" target="_blank">http://www.jpl.nasa.gov/galileo/sepo</a>..<br /><br /><a href="http://photojournal.jpl.nasa.gov/catalog/PIA01065" onclick="window.open(this.href); return false;" title="Voir l'image PIA01065: Lack of visible change around active hotspots on Io sur le site de la NASA">Voir l'image PIA01065: Lack of visible change around active hotspots on Io sur le site de la NASA.</a></div>
PIA01065: Lack of visible change around active hotspots on Io
<h1>PIA01066: Changes around Marduk between Voyager, and Galileo's first two orbits</h1><div class="PIA01066" lang="en" style="width:378px;text-align:left;margin:auto;background-color:#000;padding:10px;max-height:150px;overflow:auto;">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.<p>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).<p>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 <a href="http://www2.jpl.nasa.gov/galileo/sepo/" target="_blank">http://www.jpl.nasa.gov/galileo/sepo</a>..<br /><br /><a href="http://photojournal.jpl.nasa.gov/catalog/PIA01066" onclick="window.open(this.href); return false;" title="Voir l'image PIA01066: Changes around Marduk between Voyager, and Galileo's first two orbits sur le site de la NASA">Voir l'image PIA01066: Changes around Marduk between Voyager, and Galileo's first two orbits sur le site de la NASA.</a></div>
PIA01066: Changes around Marduk between Voyager, and Galileo's first two orbits
<h1>PIA01067: Changes on Io around Maui and Amirani between Voyager 1 and Galileo's second orbit</h1><div class="PIA01067" lang="en" style="width:208px;text-align:left;margin:auto;background-color:#000;padding:10px;max-height:150px;overflow:auto;">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.<p>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).<p>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 <a href="http://www2.jpl.nasa.gov/galileo/sepo/" target="_blank">http://www.jpl.nasa.gov/galileo/sepo</a>..<br /><br /><a href="http://photojournal.jpl.nasa.gov/catalog/PIA01067" onclick="window.open(this.href); return false;" title="Voir l'image PIA01067: Changes on Io around Maui and Amirani between Voyager 1 and Galileo's second orbit sur le site de la NASA">Voir l'image PIA01067: Changes on Io around Maui and Amirani between Voyager 1 and Galileo's second orbit sur le site de la NASA.</a></div>
PIA01067: Changes on Io around Maui and Amirani between Voyager 1 and Galileo's second orbit
<h1>PIA01068: Changes east of Pele between Galileo's first two orbits</h1><div class="PIA01068" lang="en" style="width:153px;text-align:left;margin:auto;background-color:#000;padding:10px;max-height:150px;overflow:auto;">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.<p>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).<p>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 <a href="http://www2.jpl.nasa.gov/galileo/sepo/" target="_blank">http://www.jpl.nasa.gov/galileo/sepo</a>..<br /><br /><a href="http://photojournal.jpl.nasa.gov/catalog/PIA01068" onclick="window.open(this.href); return false;" title="Voir l'image PIA01068: Changes east of Pele between Galileo's first two orbits sur le site de la NASA">Voir l'image PIA01068: Changes east of Pele between Galileo's first two orbits sur le site de la NASA.</a></div>
PIA01068: Changes east of Pele between Galileo's first two orbits
<h1>PIA01069: Active Volcanic Eruptions on Io</h1><div class="PIA01069" lang="en" style="width:660px;text-align:left;margin:auto;background-color:#000;padding:10px;max-height:150px;overflow:auto;"><p>Six views of the volcanic plume named Prometheus, as seen against Io's disk and near the bright limb (edge) of the satellite by the SSI camera on the Galileo spacecraft during its second (G2) orbit of Jupiter. North is to the top of each frame. To the south-southeast of Prometheus is another bright spot that appears to be an active plume erupting from a feature named Culann Patera. Prometheus was active 17 years ago during both Voyager flybys, but no activity was detected by Voyager at Culann. Both of these plumes were seen to glow in the dark in an eclipse image acquired by the imaging camera during Galileo's first (G1) orbit, and hot spots at these locations were detected by Galileo's Near-Infrared Mapping Spectrometer.<p>The plumes are thought to be driven by heating sulfur dioxide in Io's subsurface into an expanding fluid or "geyser." The long-lived nature of these eruptions requires that a substantial supply of sulfur dioxide must be available in Io's subsurface, similar to groundwater. Sulfur dioxide gas condenses into small particles of "snow" in the expanding plume, and the small particles scatter light and appear bright at short wavelengths. The images shown here were acquired through the shortest-wavelength filter (violet) of the Galileo camera. Prometheus is about 300 km wide and 75 km high and Culann is about 150 km wide and less than 50 km high. The images were acquired on September 4, 1996 at a range of 2,000,000 km (20 km/pixel resolution). Prometheus is named after the Greek fire god and Culann is named after the Celtic smith god.<p>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).<p>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 <a href="http://www2.jpl.nasa.gov/galileo/sepo/" target="_blank">http://www.jpl.nasa.gov/galileo/sepo</a>..<br /><br /><a href="http://photojournal.jpl.nasa.gov/catalog/PIA01069" onclick="window.open(this.href); return false;" title="Voir l'image PIA01069: Active Volcanic Eruptions on Io sur le site de la NASA">Voir l'image PIA01069: Active Volcanic Eruptions on Io sur le site de la NASA.</a></div>
PIA01069: Active Volcanic Eruptions on Io
<h1>PIA01070: Changes on Io between Voyager 1 and Galileo's second orbit around an unnamed vent North of Prometheus</h1><div class="PIA01070" lang="en" style="width:168px;text-align:left;margin:auto;background-color:#000;padding:10px;max-height:150px;overflow:auto;">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.<p>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).<p>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 <a href="http://www2.jpl.nasa.gov/galileo/sepo/" target="_blank">http://www.jpl.nasa.gov/galileo/sepo</a>..<br /><br /><a href="http://photojournal.jpl.nasa.gov/catalog/PIA01070" onclick="window.open(this.href); return false;" title="Voir l'image PIA01070: Changes on Io between Voyager 1 and Galileo's second orbit around an unnamed vent North of Prometheus sur le site de la NASA">Voir l'image PIA01070: Changes on Io between Voyager 1 and Galileo's second orbit around an unnamed vent North of Prometheus sur le site de la NASA.</a></div>
PIA01070: Changes on Io between Voyager 1 and Galileo's second orbit around an unnamed vent North of Prometheus
<h1>PIA01071: Changes on Io around Volund between Voyager 1 and Galileo's second orbit</h1><div class="PIA01071" lang="en" style="width:228px;text-align:left;margin:auto;background-color:#000;padding:10px;max-height:150px;overflow:auto;">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.<p>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).<p>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 <a href="http://www2.jpl.nasa.gov/galileo/sepo/" target="_blank">http://www.jpl.nasa.gov/galileo/sepo</a>..<br /><br /><a href="http://photojournal.jpl.nasa.gov/catalog/PIA01071" onclick="window.open(this.href); return false;" title="Voir l'image PIA01071: Changes on Io around Volund between Voyager 1 and Galileo's second orbit sur le site de la NASA">Voir l'image PIA01071: Changes on Io around Volund between Voyager 1 and Galileo's second orbit sur le site de la NASA.</a></div>
PIA01071: Changes on Io around Volund between Voyager 1 and Galileo's second orbit
<h1>PIA01081: Color Mosaic and Active Volcanic Plumes on Io</h1><div class="PIA01081" lang="en" style="width:800px;text-align:left;margin:auto;background-color:#000;padding:10px;max-height:150px;overflow:auto;">This color image, acquired during Galileo's ninth orbit (C9) around Jupiter, shows two volcanic plumes on Io. One plume was captured on the bright limb or edge of the moon, erupting over a caldera (volcanic depression) named Pillan Patera. 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 (373 miles). The second plume, seen near the terminator, the boundary between day and night, is called Prometheus after the Greek fire god). The shadow of the 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 HST images.<p>Color images from orbit C9 have been merged with a high resolution mosaic of images acquired in various orbits to enhance the surface detail. <a href="/catalog/PIA00703"> PIA00703</a> is another version of this image which also includes detailed insets of the plumes.<p>North is to the top of the picture. The resolution is about 2 kilometers (1.2 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 C9 images were obtained on June 28, 1997 at a range of more than 600,000 kilometers (372, 000 miles).<p>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).<p>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.<br /><br /><a href="http://photojournal.jpl.nasa.gov/catalog/PIA01081" onclick="window.open(this.href); return false;" title="Voir l'image PIA01081: Color Mosaic and Active Volcanic Plumes on Io sur le site de la NASA">Voir l'image PIA01081: Color Mosaic and Active Volcanic Plumes on Io sur le site de la NASA.</a></div>
PIA01081: Color Mosaic and Active Volcanic Plumes on Io
<h1>PIA01094: Io Degassing from sub- and anti-Jupiter Regions</h1><div class="PIA01094" lang="en" style="width:800px;text-align:left;margin:auto;background-color:#000;padding:10px;max-height:150px;overflow:auto;">Shown here are color-coded images of Io in eclipse (top). The images were acquired by NASA's Galileo spacecraft during its tenth orbit around Jupiter. The corresponding views of Io in reflected light are shown at the bottom. The white lines delimit Io's equator and longitudes of 0 (left) and 180 degrees (right). Io always keeps the same hemisphere (longitude 0) facing Jupiter, just as the nearside of the Moon always faces Earth. Furthermore, Io is not a perfect sphere; it is elongated along the axis which is radial to Jupiter (the "a" axis). The solid-body tides on Io have the greatest amplitude (about 50 meters) where the a axis intersects the surface, at the sub-Jupiter point (latitude 0, longitude 0) and at the anti-Jupiter point (latitude 0, longitude 180 degrees).<p>From these eclipse images we see evidence for enhanced concentrations of volcanic gases (dominantly SO2) at the sub- and anti-Jupiter regions. This enhanced degassing may be due directly to the tides or may be due to enhanced heat flow at depth below these regions.<p>North is to the top of the picture. The eclipse resolutions are 13.2 (left) and 63 (right) kilometers per picture element. The images were taken on September 18, 1997 (left) and October 5, 1997 (right) by the Solid State Imaging (SSI) system on NASA's Galileo spacecraft.<p>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).<p>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.<br /><br /><a href="http://photojournal.jpl.nasa.gov/catalog/PIA01094" onclick="window.open(this.href); return false;" title="Voir l'image PIA01094: Io Degassing from sub- and anti-Jupiter Regions sur le site de la NASA">Voir l'image PIA01094: Io Degassing from sub- and anti-Jupiter Regions sur le site de la NASA.</a></div>
PIA01094: Io Degassing from sub- and anti-Jupiter Regions
<h1>PIA01103: Geologic Landforms on Io (Area 1)</h1><div class="PIA01103" lang="en" style="width:743px;text-align:left;margin:auto;background-color:#000;padding:10px;max-height:150px;overflow:auto;">Shown here is one of the topographic mapping images of Jupiter's moon Io (Latitude: -20 to +65 degrees, Longitude: 90 to 175 degrees) acquired by NASA's Galileo spacecraft, revealing a great variety of landforms. There are rugged mountains several miles high, layered materials forming plateaus, and many irregular depressions called volcanic calderas. There are also dark lava flows and bright deposits of SO2 frost or other sulfurous materials, which have no discernable topographic relief at this scale. Several of the dark, flow-like features correspond to hot spots, and may be active lava flows. There are no landforms resembling impact craters, as the volcanism covers the surface with new deposits much more rapidly than the flux of comets and asteroids can create large impact craters.<p>North is to the top of the picture and the sun illuminates the surface from the left. The image covers an area about 2600 kilometers wide and the smallest features that can be discerned are 3.5 kilometers in size. This image was taken on November 6th, 1996, at a range of 339,400 kilometers by the Solid State Imaging (CCD) system on the Galileo Spacecraft.<p>The Jet Propulsion Laboratory, Pasadena, CA manages the mission for NASA's Office of Space Science, Washington, DC.<p>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 <a href="http://www2.jpl.nasa.gov/galileo/sepo/" target="_blank">http://www.jpl.nasa.gov/galileo/sepo</a>..<br /><br /><a href="http://photojournal.jpl.nasa.gov/catalog/PIA01103" onclick="window.open(this.href); return false;" title="Voir l'image PIA01103: Geologic Landforms on Io (Area 1) sur le site de la NASA">Voir l'image PIA01103: Geologic Landforms on Io (Area 1) sur le site de la NASA.</a></div>
PIA01103: Geologic Landforms on Io (Area 1)
<h1>PIA01104: Geologic Landforms on Io (Area 2)</h1><div class="PIA01104" lang="en" style="width:800px;text-align:left;margin:auto;background-color:#000;padding:10px;max-height:150px;overflow:auto;">Shown here is one of the topographic mapping images of Jupiter's moon Io (Latitude: +5 to +48 degrees, Longitude: 120 to 185 degrees) acquired by NASA's Galileo spacecraft, revealing a great variety of landforms. There are rugged mountains several miles high, layered materials forming plateaus, and many irregular depressions called volcanic calderas. There are also dark lava flows and bright deposits of SO2 frost or other sulfurous materials, which have no discernable topographic relief at this scale. Several of the dark, flow-like features correspond to hot spots, and may be active lava flows. There are no landforms resembling impact craters, as the volcanism covers the surface with new deposits much more rapidly than the flux of comets and asteroids can create large impact craters.<p>North is to the top of the picture and the sun illuminates the surface from the left. The bright region beyond Io's limb (upper right corner) is Jupiter's atmosphere. The image covers an area about 2080 kilometers wide and the smallest features that can be discerned are 2.6 kilometers in size. This image was taken on November 6th, 1996, at a range of 258,100 kilometers by the Solid State Imaging (CCD) system on the Galileo Spacecraft.<p>The Jet Propulsion Laboratory, Pasadena, CA manages the mission for NASA's Office of Space Science, Washington, DC.<p>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 <a href="http://www2.jpl.nasa.gov/galileo/sepo/" target="_blank">http://www.jpl.nasa.gov/galileo/sepo</a>..<br /><br /><a href="http://photojournal.jpl.nasa.gov/catalog/PIA01104" onclick="window.open(this.href); return false;" title="Voir l'image PIA01104: Geologic Landforms on Io (Area 2) sur le site de la NASA">Voir l'image PIA01104: Geologic Landforms on Io (Area 2) sur le site de la NASA.</a></div>
PIA01104: Geologic Landforms on Io (Area 2)
<h1>PIA01105: Geologic Landforms on Io (Area 3)</h1><div class="PIA01105" lang="en" style="width:800px;text-align:left;margin:auto;background-color:#000;padding:10px;max-height:150px;overflow:auto;">Shown here is one of the topographic mapping images of Jupiter's moon Io (Latitude: +2 to +65 degrees, Longitude: 150 to 223 degrees) acquired by NASA's Galileo spacecraft, revealing a great variety of landforms. There are rugged mountains several miles high, layered materials forming plateaus, and many irregular depressions called volcanic calderas. There are also dark lava flows and bright deposits of SO2 frost or other sulfurous materials, which have no discernable topographic relief at this scale. Several of the dark, flow-like features correspond to hot spots, and may be active lava flows. There are no landforms resembling impact craters, as the volcanism covers the surface with new deposits much more rapidly than the flux of comets and asteroids can create large impact craters.<p>North is to the top of the picture and the sun illuminates the surface from the left. The image covers an area about 2000 kilometers wide and the smallest features that can be discerned are 2.5 kilometers in size. This image was taken on November 6th, 1996, at a range of 245,719 kilometers by the Solid State Imaging (CCD) system on the Galileo Spacecraft.<p>The Jet Propulsion Laboratory, Pasadena, CA manages the mission for NASA's Office of Space Science, Washington, DC.<p>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 <a href="http://www2.jpl.nasa.gov/galileo/sepo/" target="_blank">http://www.jpl.nasa.gov/galileo/sepo</a>..<br /><br /><a href="http://photojournal.jpl.nasa.gov/catalog/PIA01105" onclick="window.open(this.href); return false;" title="Voir l'image PIA01105: Geologic Landforms on Io (Area 3) sur le site de la NASA">Voir l'image PIA01105: Geologic Landforms on Io (Area 3) sur le site de la NASA.</a></div>
PIA01105: Geologic Landforms on Io (Area 3)
<h1>PIA01106: Geologic Landforms on Io (Area 4)</h1><div class="PIA01106" lang="en" style="width:797px;text-align:left;margin:auto;background-color:#000;padding:10px;max-height:150px;overflow:auto;">Shown here is one of the topographic mapping images of Jupiter's moon Io (Latitude: -60 to 20 degrees, Longitude: 180 to 270 degrees) acquired by NASA's Galileo spacecraft, revealing a great variety of landforms. There are rugged mountains several miles high, layered materials forming plateaus, and many irregular depressions called volcanic calderas. There are also dark lava flows and bright deposits of SO2 frost or other sulfurous materials, which have no discernable topographic relief at this scale. Several of the dark, flow-like features correspond to hot spots, and may be active lava flows. There are no landforms resembling impact craters, as the volcanism covers the surface with new deposits much more rapidly than the flux of comets and asteroids can create large impact craters. The large oval on the left-hand side is the fallout deposit from Pele, the largest volcanic eruption plume on Io, over 200 miles high when active.<p>North is to the top of the picture and the sun illuminates the surface from the left. The image covers an area about 2390 kilometers wide and the smallest features that can be discerned are 3.0 kilometers in size. This image was taken on November 6th, 1996, at a range of 294,000 kilometers by the Solid State Imaging (CCD) system on the Galileo Spacecraft.<p>The Jet Propulsion Laboratory, Pasadena, CA manages the mission for NASA's Office of Space Science, Washington, DC.<p>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 <a href="http://www2.jpl.nasa.gov/galileo/sepo/" target="_blank">http://www.jpl.nasa.gov/galileo/sepo</a>..<br /><br /><a href="http://photojournal.jpl.nasa.gov/catalog/PIA01106" onclick="window.open(this.href); return false;" title="Voir l'image PIA01106: Geologic Landforms on Io (Area 4) sur le site de la NASA">Voir l'image PIA01106: Geologic Landforms on Io (Area 4) sur le site de la NASA.</a></div>
PIA01106: Geologic Landforms on Io (Area 4)
<h1>PIA01107: Geologic Landforms on Io (Area 5)</h1><div class="PIA01107" lang="en" style="width:685px;text-align:left;margin:auto;background-color:#000;padding:10px;max-height:150px;overflow:auto;">Shown here is one of the topographic mapping images of Jupiter's moon Io (Latitude: -40 to +90 degrees, Longitude: 210-320 degrees) acquired by NASA's Galileo spacecraft, revealing a great variety of landforms. There are rugged mountains several miles high, layered materials forming plateaus, and many irregular depressions called volcanic calderas. There are also dark lava flows and bright deposits of SO2 frost or other sulfurous materials, which have no discernable topographic relief at this scale. Several of the dark, flow-like features correspond to hot spots, and may be active lava flows. There are no landforms resembling impact craters, as the volcanism covers the surface with new deposits much more rapidly than the flux of comets and asteroids can create large impact craters. The volcano Ra Patera, seen to have an active plume 75 km high during Galileo's first orbit in June 1996, is located on the bright limb of this image but no plume can be seen, so it is now (5 months later) inactive.<p>North is to the top of the picture and the sun illuminates the surface from the left. The image covers an area about 2800 kilometers wide and the smallest features that can be discerned are 4.1 kilometers in size. This image was taken on November 6th, 1996, at a range of 403,100 kilometers by the Solid State Imaging (CCD) system on the Galileo Spacecraft.<p>The Jet Propulsion Laboratory, Pasadena, CA manages the mission for NASA's Office of Space Science, Washington, DC.<p>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 <a href="http://www2.jpl.nasa.gov/galileo/sepo/" target="_blank">http://www.jpl.nasa.gov/galileo/sepo</a>..<br /><br /><a href="http://photojournal.jpl.nasa.gov/catalog/PIA01107" onclick="window.open(this.href); return false;" title="Voir l'image PIA01107: Geologic Landforms on Io (Area 5) sur le site de la NASA">Voir l'image PIA01107: Geologic Landforms on Io (Area 5) sur le site de la NASA.</a></div>
PIA01107: Geologic Landforms on Io (Area 5)
<h1>PIA01108: Mosaic of Io</h1><div class="PIA01108" lang="en" style="width:800px;text-align:left;margin:auto;background-color:#000;padding:10px;max-height:150px;overflow:auto;">Mosaic of images of Io acquired during orbit C3, showing more than half of Io's surface. These are the best images available to show topographic features over most of this region. The map projection is called Simple Cylindrical, and the grid lines mark 10 degree intervals of latitude and longitude.<p>The mosaic covers an area of about 8 million square kilometers, and the finest details that can discerned are about 2.5 kilometers in size. North is to the top of the picture and the sun illuminates the surface from the left. The images which form this mosaic were obtained through the clear filter of the Solid State Imaging (CCD) system aboard NASA's Galileo spacecraft on Nov. 6, 1996 (Universal Time) at a range which varied from 245,719 kilometers to 403,100 kilometers.<p>The Jet Propulsion Laboratory, Pasadena, CA manages the mission for NASA's Office of Space Science, Washington, DC.<p>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 <a href="http://www2.jpl.nasa.gov/galileo/sepo/" target="_blank">http://www.jpl.nasa.gov/galileo/sepo</a>..<br /><br /><a href="http://photojournal.jpl.nasa.gov/catalog/PIA01108" onclick="window.open(this.href); return false;" title="Voir l'image PIA01108: Mosaic of Io sur le site de la NASA">Voir l'image PIA01108: Mosaic of Io sur le site de la NASA.</a></div>
PIA01108: Mosaic of Io
<h1>PIA01109: Io's Sodium Cloud (Clear Filter)</h1><div class="PIA01109" lang="en" style="width:390px;text-align:left;margin:auto;background-color:#000;padding:10px;max-height:150px;overflow:auto;"><p>This image of Jupiter's moon Io and its surrounding sky is shown in false color. It was taken at 5 hours 30 minutes Universal Time on Nov. 9, 1996 by the solid state imaging (CCD) system aboard NASA's Galileo spacecraft, using a clear filter whose wavelength range was approximately 400 to 1100 nanometers. This picture differs in two main ways from the green-yellow filter image of the same scene which was released yesterday.<p>First, the sky around Io is brighter, partly because the wider wavelength range of the clear filter lets in more scattered light from Io's illuminated crescent and from Prometheus' sunlit plume. Nonetheless, the overall sky brightness in this frame is comparable to that seen through the green-yellow filter, indicating that even here much of the diffuse sky emission is coming from the wavelength range of the green-yellow filter (i.e., from Io's Sodium Cloud).<p>The second major difference is that a quite large roundish spot has appeared in Io's southern hemisphere. This spot -- which has been colored red -- corresponds to thermal emission from the volcano Pele. The green-yellow filter image bears a much smaller trace of this emission because the clear filter is far more sensitive to those relatively long wavelengths where thermal emission is strongest.<p>The Jet Propulsion Laboratory, Pasadena, CA manages the mission for NASA's Office of Space Science, Washington, DC.<p>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 <a href="http://www2.jpl.nasa.gov/galileo/sepo/" target="_blank">http://www.jpl.nasa.gov/galileo/sepo</a>.<br /><br /><a href="http://photojournal.jpl.nasa.gov/catalog/PIA01109" onclick="window.open(this.href); return false;" title="Voir l'image PIA01109: Io's Sodium Cloud (Clear Filter) sur le site de la NASA">Voir l'image PIA01109: Io's Sodium Cloud (Clear Filter) sur le site de la NASA.</a></div>
PIA01109: Io's Sodium Cloud (Clear Filter)
<h1>PIA01110: Io's Sodium Cloud (Clear and Green-Yellow Filters)</h1><div class="PIA01110" lang="en" style="width:388px;text-align:left;margin:auto;background-color:#000;padding:10px;max-height:150px;overflow:auto;"><p>The green-yellow filter and clear filter images of Io which were released over the past two days were originally exposed on the same frame. The camera pointed in slightly different directions for the two exposures, placing a clear filter image of Io on the top half of the frame, and a green-yellow filter image of Io on the bottom half of the frame. This picture shows that entire original frame in false color, the most intense emission appearing white.<p>East is to the right. Most of Io's visible surface is in shadow, though one can see part of an illuminated crescent on its western side. The burst of white light near Io's eastern equatorial edge (most distinctive in the green filter image) is sunlight scattered by the plume of the volcano Prometheus.<p>There is much more bright light near Io in the clear filter image, since that filter's wider wavelength range admits more scattered light from Prometheus' sunlit plume and Io's illuminated crescent. Thus in the clear filter image especially, Prometheus's plume was bright enough to produce several white spikes which extend radially outward from the center of the plume emission. These spikes are artifacts produced by the optics of the camera. Two of the spikes in the clear filter image appear against Io's shadowed surface, and the lower of these is pointing towards a bright round spot. That spot corresponds to thermal emission from the volcano Pele.<p>The Jet Propulsion Laboratory, Pasadena, CA manages the mission for NASA's Office of Space Science, Washington, DC.<p>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 <a href="http://www2.jpl.nasa.gov/galileo/sepo/" target="_blank">http://www.jpl.nasa.gov/galileo/sepo</a>.<br /><br /><a href="http://photojournal.jpl.nasa.gov/catalog/PIA01110" onclick="window.open(this.href); return false;" title="Voir l'image PIA01110: Io's Sodium Cloud (Clear and Green-Yellow Filters) sur le site de la NASA">Voir l'image PIA01110: Io's Sodium Cloud (Clear and Green-Yellow Filters) sur le site de la NASA.</a></div>
PIA01110: Io's Sodium Cloud (Clear and Green-Yellow Filters)
<h1>PIA01111: Io's Sodium Cloud On-Chip Format (Clear and Green-Yellow Filters Superimposed)</h1><div class="PIA01111" lang="en" style="width:390px;text-align:left;margin:auto;background-color:#000;padding:10px;max-height:150px;overflow:auto;"><p>This image of Jupiter's moon Io and its surrounding sky is shown in false color. The solid state imaging (CCD) system on NASA's Galileo spacecraft originally took two images of this scene, one through a clear filter and one through a green-yellow filter. [Versions of these images have been released over the past 3 days.] This picture was created by: (i) adding green color to the image taken through the green-yellow filter, and red color to the image taken through the clear filter; (ii) superimposing the two resulting images. Thus features in this picture which are purely green (or purely red) originally appeared only in the green-yellow (or clear) filter image of this scene. Features which are yellowish appeared in both filters. North is at the top, and east is to the right.<p>This image reveals several new things about this scene. For example:<p>(1) The reddish emission south of Io came dominantly through the clear filter. It therefore probably represents scattered light from Io's lit crescent and Prometheus' plume, rather than emission from Io's Sodium Cloud (which came through both filters).<p>(2) The roundish red spot in Io's southern hemisphere contains a small yellow spot. This means that some thermal emission from the volcano Pele was detected by the green-yellow filter (as well as by the clear filter).<p>(3) The sky contains several concentrated yellowish spots which were thus seen at the same location on the sky through both filters (one such spot appears in the picture's northeast corner). These spots are almost certainly stars. By contrast, the eastern half of this image contains a number of green spots whose emission was thus detected by the green-yellow filter only. Since any star visible through the green-yellow filter would also be visible through the clear filter, these green spots are probably artifacts (e.g., cosmic ray hits on the CCD sensor).<p>The Jet Propulsion Laboratory, Pasadena, CA manages the mission for NASA's Office of Space Science, Washington, DC.<p>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 <a href="http://www2.jpl.nasa.gov/galileo/sepo/" target="_blank">http://www.jpl.nasa.gov/galileo/sepo</a>.<br /><br /><a href="http://photojournal.jpl.nasa.gov/catalog/PIA01111" onclick="window.open(this.href); return false;" title="Voir l'image PIA01111: Io's Sodium Cloud On-Chip Format (Clear and Green-Yellow Filters Superimposed) sur le site de la NASA">Voir l'image PIA01111: Io's Sodium Cloud On-Chip Format (Clear and Green-Yellow Filters Superimposed) sur le site de la NASA.</a></div>
PIA01111: Io's Sodium Cloud On-Chip Format (Clear and Green-Yellow Filters Superimposed)
<h1>PIA01112: Pele Plume Deposit on Io</h1><div class="PIA01112" lang="en" style="width:792px;text-align:left;margin:auto;background-color:#000;padding:10px;max-height:150px;overflow:auto;">The varied effects of Ionian volcanism can be seen in this false color infrared composite image of Io's trailing hemisphere. Low resolution color data from Galileo's first orbit (June, 1996) have been combined with a higher resolution clear filter picture taken on the third orbit (November, 1996) of the spacecraft around Jupiter.<p>A diffuse ring of bright red material encircles Pele, the site of an ongoing, high velocity volcanic eruption. Pele's plume is nearly invisible, except in back-lit photographs, but its deposits indicate energetic ejection of sulfurous materials out to distances more than 600 kilometers from the central vent. Another bright red deposit lies adjacent to Marduk, also a currently active ediface. High temperature hot spots have been detected at both these locations, due to the eruption of molten material in lava flows or lava lakes. Bright red deposits on Io darken and disappear within years or decades of deposition, so the presence of bright red materials marks the sites of recent volcanism.<p>This composite was created from data obtained by the Solid State Imaging (CCD) system aboard NASA's Galileo spacecraft. The region imaged is centered on 15 degrees South, 224 degrees West, and is almost 2400 kilometers across. The finest details that can be discerned in this picture are about 3 kilometers across. North is towards the top of the picture and the sun illuminates the surface from the west.<p>The Jet Propulsion Laboratory, Pasadena, CA manages the mission for NASA's Office of Space Science, Washington, DC.<p>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 <a href="http://www2.jpl.nasa.gov/galileo/sepo/" target="_blank">http://www.jpl.nasa.gov/galileo/sepo</a>..<br /><br /><a href="http://photojournal.jpl.nasa.gov/catalog/PIA01112" onclick="window.open(this.href); return false;" title="Voir l'image PIA01112: Pele Plume Deposit on Io sur le site de la NASA">Voir l'image PIA01112: Pele Plume Deposit on Io sur le site de la NASA.</a></div>
PIA01112: Pele Plume Deposit on Io
<h1>PIA01129: Interior of Io</h1><div class="PIA01129" lang="en" style="width:800px;text-align:left;margin:auto;background-color:#000;padding:10px;max-height:150px;overflow:auto;"><p>Cutaway view of the possible internal structure of Io The surface of the satellite is a mosaic of images obtained in 1979 by NASA's Voyager spacecraft The interior characteristics are inferred from gravity field and magnetic field measurements by NASA's Galileo spacecraft. Io's radius is 1821 km, similar to the 1738 km radius of our Moon; Io has a metallic (iron, nickel) core (shown in gray) drawn to the correct relative size. The core is surrounded by a rock shell (shown in brown). Io's rock or silicate shell extends to the surface.<p>The Jet Propulsion Laboratory, Pasadena, CA manages the mission for NASA's Office of Space Science, Washington, DC.<p>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 <a href="http://www2.jpl.nasa.gov/galileo/sepo/" target="_blank">http://www.jpl.nasa.gov/galileo/sepo</a>.<br /><br /><a href="http://photojournal.jpl.nasa.gov/catalog/PIA01129" onclick="window.open(this.href); return false;" title="Voir l'image PIA01129: Interior of Io sur le site de la NASA">Voir l'image PIA01129: Interior of Io sur le site de la NASA.</a></div>
PIA01129: Interior of Io
<h1>PIA01217: Topography of Io</h1><div class="PIA01217" lang="en" style="width:410px;text-align:left;margin:auto;background-color:#000;padding:10px;max-height:150px;overflow:auto;">This image of Io was acquired by Galileo during its ninth orbit (C9) of Jupiter as part of a sequence of images designed to cover Io at low illumination angles to map the landforms. Obtaining images at such illuminations 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.<p>North is to the top of the picture. 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.<p>The Jet Propulsion Laboratory, Pasadena, CA manages the mission for NASA's Office of Space Science, Washington, DC.<p>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 <a href="http://www2.jpl.nasa.gov/galileo/sepo/" target="_blank">http://www.jpl.nasa.gov/galileo/sepo</a>..<br /><br /><a href="http://photojournal.jpl.nasa.gov/catalog/PIA01217" onclick="window.open(this.href); return false;" title="Voir l'image PIA01217: Topography of Io sur le site de la NASA">Voir l'image PIA01217: Topography of Io sur le site de la NASA.</a></div>
PIA01217: Topography of Io
<h1>PIA01218: Mountains and Plateaus on Io</h1><div class="PIA01218" lang="en" style="width:800px;text-align:left;margin:auto;background-color:#000;padding:10px;max-height:150px;overflow:auto;">These two views of Io were acquired by NASA's Galileo spacecraft during its seventh orbit (G7) of Jupiter. The images were designed to view large features on Io at low sun angles when the lighting conditions emphasize the topography or relief of the volcanic satellite. Sun angles are low near the terminator which is the day-night boundary near the left side of the images. These images reveal that the topography is very flat near the active volcanic centers such as Loki Patera (the large dark horseshoe-shaped feature near the terminator in the left-hand image) and that a variety of mountains and plateaus exist elsewhere.<p>North is to the top of the picture. The resolution is about 6 kilometers per picture element (6.1 for the left hand image and 5.7 for the right). The images were taken on April 4th, 1997 at a ranges of 600,000 kilometers (left image) and 563,000 kilometers (right image) by the solid state imaging (CCD) system on NASA's Galileo spacecraft.<p>The Jet Propulsion Laboratory, Pasadena, CA manages the mission for NASA's Office of Space Science, Washington, DC.<p>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 <a href="http://www2.jpl.nasa.gov/galileo/sepo/" target="_blank">http://www.jpl.nasa.gov/galileo/sepo</a>..<br /><br /><a href="http://photojournal.jpl.nasa.gov/catalog/PIA01218" onclick="window.open(this.href); return false;" title="Voir l'image PIA01218: Mountains and Plateaus on Io sur le site de la NASA">Voir l'image PIA01218: Mountains and Plateaus on Io sur le site de la NASA.</a></div>
PIA01218: Mountains and Plateaus on Io
<h1>PIA01220: Io's Kanehekili Hemisphere</h1><div class="PIA01220" lang="en" style="width:346px;text-align:left;margin:auto;background-color:#000;padding:10px;max-height:150px;overflow:auto;">This color composite of Io, acquired by Galileo during its ninth orbit (C9) of Jupiter, shows the hemisphere of Io which is centered at longitude 52 degrees. The dark feature just to the lower right of the center of the disk is called Kanehekili. Named after an Hawaiian thunder god, Kanehekili contains two persistent high temperature hot spots and a "new" active volcanic plume. NASA's Voyager spacecraft returned images of nine active plumes during its 1979 flyby of this dynamic satellite. To date, Galileo's plume monitoring observations have shown continued activity at four of those nine plume locations as well as new activity at six other locations.<p>North is to the top of the picture which combines images acquired using violet, green, and near-infrared (756 micrometers) filters. The resolution is 21 kilometers per picture element. The images were taken on June 27, 1997 at a range of 1,033,000 kilometers by the solid state imaging (CCD) system on NASA's Galileo spacecraft.<p>The Jet Propulsion Laboratory, Pasadena, CA manages the mission for NASA's Office of Space Science, Washington, DC.<p>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 <a href="http://www2.jpl.nasa.gov/galileo/sepo/" target="_blank">http://www.jpl.nasa.gov/galileo/sepo</a>..<br /><br /><a href="http://photojournal.jpl.nasa.gov/catalog/PIA01220" onclick="window.open(this.href); return false;" title="Voir l'image PIA01220: Io's Kanehekili Hemisphere sur le site de la NASA">Voir l'image PIA01220: Io's Kanehekili Hemisphere sur le site de la NASA.</a></div>
PIA01220: Io's Kanehekili Hemisphere
<h1>PIA01223: Changes on Io's Loki-Pele hemisphere</h1><div class="PIA01223" lang="en" style="width:646px;text-align:left;margin:auto;background-color:#000;padding:10px;max-height:150px;overflow:auto;">This color composite of Io was acquired by Galileo during its sixth orbit (E6) of Jupiter as part of a sequence of images designed to monitor changes in the surface color due to volcanic activity. Two prominent features in this hemisphere are Pele (the big red ring) and Loki (the dark horseshoe shaped feature). Amaterasu Patera, the dark spot north of Loki, has darkened since G1. The new deposits at Ra Patera (below Loki) have faded in appearance since the images taken eight months earlier during Galileo's first orbit (G1). (<a href="/catalog/PIA00709">Compare</a> this view of Ra Patera with the Galileo images from June 1996 and Voyager images obtained in 1979. A <a href="/catalog/PIA00293">limb view</a> showing the erupting plume during G1 is available as well.)<p>North is to the top of the picture which combines images acquired using violet, green, and near-infrared (756 micrometers) filters. The resolution is 11.2 kilometers per picture element. The images were taken on February 20, 1997 at a range of 554,000 kilometers by the solid state imaging (CCD) system on NASA's Galileo spacecraft.<p>The Jet Propulsion Laboratory, Pasadena, CA manages the mission for NASA's Office of Space Science, Washington, DC.<p>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 <a href="http://www2.jpl.nasa.gov/galileo/sepo/" target="_blank">http://www.jpl.nasa.gov/galileo/sepo</a>..<br /><br /><a href="http://photojournal.jpl.nasa.gov/catalog/PIA01223" onclick="window.open(this.href); return false;" title="Voir l'image PIA01223: Changes on Io's Loki-Pele hemisphere sur le site de la NASA">Voir l'image PIA01223: Changes on Io's Loki-Pele hemisphere sur le site de la NASA.</a></div>
PIA01223: Changes on Io's Loki-Pele hemisphere
<h1>PIA01260: Hubble Discovers Bright New Spot on Io</h1><div class="PIA01260" lang="en" style="width:800px;text-align:left;margin:auto;background-color:#000;padding:10px;max-height:150px;overflow:auto;"><p>This NASA Hubble Space Telescope pair of images of Jupiter's volcanic moon Io shows the surprising emergence of a 200-mile diameter large yellowish-white feature near the center of the moon's disk (photo on the right). This is a more dramatic change in 16 months than any seen over the previous 15 years, say researchers. They suggest the spot may be a new class of transient feature on the moon. For comparison the photo on the left was taken in March 1994 -- before the spot emerged - - and shows that Io's surface had undergone only subtle changes since it was last seen close-up by the Voyager 2 probe in 1979. The new spot seen in the July 1995 Hubble image replaces a smaller whitish spot seen in about the same place in the March 1994 image. Note the much more subtle changes seen elsewhere on this face of Io over the 16 months between the images. Each image is a composite of frames taken at near-ultraviolet, violet, and yellow wavelengths, with Hubble's Wide Field and Planetary Camera 2. "The new spot surrounds the volcano Ra Patera, which was photographed by Voyager, and is probably composed of material, probably frozen gas, ejected from Ra Patera by a large volcanic explosion or fresh lava flows...," according to John Spencer of Lowell Observatory in Flagstaff, Arizona. The new bright spot is also unusual because it is much yellower than other bright regions of Io, which are whitish in color. The unusual color may result from the freshness of the deposit and will probably provide clues as to the composition of new volcanic materials on Io. The temperature on Io's surface is about -150 degrees Celsius (-238 degrees Fahrenheit); however, "hot spots" associated with volcanic activity may be as warm as 1,000 degrees Celsius (1,800 degrees Fahrenheit). Follow-up observations by Hubble, in coordination with the Galileo spacecraft, scheduled to arrive at Jupiter and fly by Io in December 1995, will reveal the evolution and lifetime of the new feature. Galileo will be able to see much greater detail on Io in visible light, but will still rely on information gleaned from Hubble UV observations and Hubble observations taken at times when Galileo cannot observe Io. These further observations should also tell whether astronomers have witnessed, for the first time, one of the processes which creates the bright regions on Io.<p>This image and other images and data received from the Hubble Space Telescope are posted on the World Wide Web on the Space Telescope Science Institute home page at URL <a href="http://oposite.stsci.edu/" class="external free" target="wpext">http://oposite.stsci.edu/</a>.<br /><br /><a href="http://photojournal.jpl.nasa.gov/catalog/PIA01260" onclick="window.open(this.href); return false;" title="Voir l'image PIA01260: Hubble Discovers Bright New Spot on Io sur le site de la NASA">Voir l'image PIA01260: Hubble Discovers Bright New Spot on Io sur le site de la NASA.</a></div>
PIA01260: Hubble Discovers Bright New Spot on Io
<h1>PIA01267: Hubble Space Telescope Resolves Volcanoes on Io</h1><div class="PIA01267" lang="en" style="width:800px;text-align:left;margin:auto;background-color:#000;padding:10px;max-height:150px;overflow:auto;"><p>This picture is a composite of a black and white near infrared image of Jupiter and its satellite Io and a color image of Io at shorter wavelengths taken at almost the same time on March 5, 1994. These are the first images of a giant planet or its satellites taken by NASA's Hubble Space Telescope (HST) since the repair mission in December 1993.<p>Io is too small for ground-based telescopes to see the surface details. The moon's angular diameter of one arc second is at the resolution limit of ground based telescopes.<p>Many of these markings correspond to volcanoes that were first revealed in 1979 during the Voyager spacecraft flyby of Jupiter. Several of the volcanoes periodically are active because Io is heated by tides raised by Jupiter's powerful gravity.<p>The volcano Pele appears as a dark spot surrounded by an irregular orange oval in the lower part of the image. The orange material has been ejected from the volcano and spread over a huge area. Though the volcano was first discovered by Voyager, the distinctive orange color of the volcanic deposits is a new discovery in these HST images. (Voyager missed it because its cameras were not sensitive to the near-infrared wavelengths where the color is apparent). The sulfur and sulfur dioxide that probably dominate Io's surface composition cannot produce this orange color, so the Pele volcano must be generating material with a more unusual composition, possibly rich in sodium.<p>The Jupiter image, taken in near-infrared light, was obtained with HST's Wide Field and Planetary Camera in wide field mode. High altitude ammonia crystal clouds are bright in this image because they reflect infrared light before it is absorbed by methane in Jupiter's atmosphere. The most prominent feature is the Great Red Spot, which is conspicuous because of its high clouds. A cap of high-altitude haze appears at Jupiter's south pole.<p>The Wide Field/Planetary Camera 2 was developed by the Jet Propulsion Laboratory and managed by the Goddard Space Flight Center for NASA's Office of Space Science.<p>This image and other images and data received from the Hubble Space Telescope are posted on the World Wide Web on the Space Telescope Science Institute home page at URL <a href="http://oposite.stsci.edu/" class="external free" target="wpext">http://oposite.stsci.edu/</a>.<br /><br /><a href="http://photojournal.jpl.nasa.gov/catalog/PIA01267" onclick="window.open(this.href); return false;" title="Voir l'image PIA01267: Hubble Space Telescope Resolves Volcanoes on Io sur le site de la NASA">Voir l'image PIA01267: Hubble Space Telescope Resolves Volcanoes on Io sur le site de la NASA.</a></div>
PIA01267: Hubble Space Telescope Resolves Volcanoes on Io
<h1>PIA01362: Io</h1><div class="PIA01362" lang="en" style="width:512px;text-align:left;margin:auto;background-color:#000;padding:10px;max-height:150px;overflow:auto;">Voyager 2 took this picture of Io on the evening of July 9, 1979, from a range of 1.2 million kilometers. On the limb of Io are two blue volcanic eruption plumes about 100 kilometers high. These two plumes were first seen by Voyager 1 in March, 1979, and are designated Plume 5 (upper) and Plume 6 (lower). They have apparently been erupting for a period of at least 4 months and probably longer. A total of six plumes have been seen by Voyager 2, all of which were first seen by Voyager 1. The largest plume viewed by Voyager 1 (Plume 1) is no longer erupting. Plume 4 was not viewed on the edge of the moon's disc by Voyager 2 and therefore it is not known whether or not it is still erupting. This picture is one of a series taken to monitor the eruptions over a 6 hour period.<br /><br /><a href="http://photojournal.jpl.nasa.gov/catalog/PIA01362" onclick="window.open(this.href); return false;" title="Voir l'image PIA01362: Io sur le site de la NASA">Voir l'image PIA01362: Io sur le site de la NASA.</a></div>
PIA01362: Io