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

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<h1>PIA00010: Io with Loki Plume on Bright Limb</h1><div class="PIA00010" lang="en" style="width:684px;text-align:left;margin:auto;background-color:#000;padding:10px;max-height:150px;overflow:auto;"><p>Voyager 1 image of Io showing active plume of Loki on limb. Heart-shaped feature southeast of Loki consists of fallout deposits from active plume Pele. The images that make up this mosaic were taken from an average distance of approximately 490,000 kilometers (340,000 miles).<br /><br /><a href="http://photojournal.jpl.nasa.gov/catalog/PIA00010" onclick="window.open(this.href); return false;" title="Voir l'image PIA00010: Io with Loki Plume on Bright Limb sur le site de la NASA">Voir l'image PIA00010: Io with Loki Plume on Bright Limb sur le site de la NASA.</a></div>
PIA00010: Io with Loki Plume on Bright Limb
<h1>PIA00021: Volcanic Caldera on Io</h1><div class="PIA00021" lang="en" style="width:582px;text-align:left;margin:auto;background-color:#000;padding:10px;max-height:150px;overflow:auto;">This photograph of Jupiter's satellite Io shows what appears to be a volcanic caldera that is venting gasses (the bright blue patch at left center). In the photo is a network of volcanic calderas with dark floors linked by bright red materials. The northernmost caldera has a bright blue patch on the floor. Scientists believe the bright blue patch may be clouds of gas issuing from volcanic vents. The gas clouds may condense to form extremely fine particles that appear blue. Since Voyager 1's infrared spectrometer has discovered sulfur dioxide on Io, it is possible that sulfur dioxide is the main component of the clouds. Sulfur dioxide clouds would rapidly freeze and snow back to the surface. It is also possible that dark areas in the floors of the calderas are pools of molten sulfur, a very dark form of sulfur. The picture was taken March 5, 1979, as Voyager 1 approached Io. Photo was taken from 80,500 miles (129,600 kilometers). The Voyager Project is managed and controlled for NASA's Office of Space Science by the Jet Propulsion Laboratory.<br /><br /><a href="http://photojournal.jpl.nasa.gov/catalog/PIA00021" onclick="window.open(this.href); return false;" title="Voir l'image PIA00021: Volcanic Caldera on Io sur le site de la NASA">Voir l'image PIA00021: Volcanic Caldera on Io sur le site de la NASA.</a></div>
PIA00021: Volcanic Caldera on Io
<h1>PIA00023: Io - Full Disk</h1><div class="PIA00023" lang="en" style="width:800px;text-align:left;margin:auto;background-color:#000;padding:10px;max-height:150px;overflow:auto;">This full-disk image of Jupiter's satellite Io was made from several frames taken by Voyager 1 on March 4, 1979, as the spacecraft neared the satellite. Io is about 862,000 kilometers (500,000 miles) away here. A variety of features can be seen in the photo that appear linked to the intense volcanic activity on Io: the circular, donut-shaped feature in the center has been identified with a known erupting volcano; other, similar features can be seen across the face of the satellite. Io's volcanic activity appears to be of at least two general kinds -- explosive eruptions that spew material into the sky as much as 250 kilometers (160 miles) altitude; and lava that flows from vents across the surface. Io is the first body in the solar system (beyond Earth) where active volcanism has been observed. The Voyager project is managed and controlled for NASA's Office of Space Science by the Jet Propulsion Laboratory.<br /><br /><a href="http://photojournal.jpl.nasa.gov/catalog/PIA00023" onclick="window.open(this.href); return false;" title="Voir l'image PIA00023: Io - Full Disk sur le site de la NASA">Voir l'image PIA00023: Io - Full Disk sur le site de la NASA.</a></div>
PIA00023: Io - Full Disk
<h1>PIA00274: Io Glowing in the Dark</h1><div class="PIA00274" lang="en" style="width:800px;text-align:left;margin:auto;background-color:#000;padding:10px;max-height:150px;overflow:auto;"><p>Volcanic hot spots and auroral emissions glow on the darkside of Jupiter's moon Io in the image at left. The image was taken by the camera onboard NASA's Galileo spacecraft on 29 June, 1996 UT while Io was in Jupiter's shadow. It is the best and highest-resolution image ever acquired of hot spots or auroral features on Io. The mosaic at right of 1979 Voyager images is shown with an identical scale and projection to identify the locations of the hot spots seen in the Galileo image. The grid marks are at 30 degree intervals of latitude and longitude. North is to the top.<p>In the nighttime Galileo image, small red ovals and perhaps some small green areas are from volcanic hot spots with temperatures of more than about 700 kelvin (about 1000 degrees Fahrenheit). Greenish areas seen near the limb, or edge of the moon, are probably the result of auroral or airglow emissions of neutral oxygen or sulfur atoms in volcanic plumes and in Io's patchy atmosphere. The image was taken from a range of 1,035,000 kilometers (about 643,000 miles).<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 <a href="http://www2.jpl.nasa.gov/galileo/sepo/" target="_blank">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/PIA00274" onclick="window.open(this.href); return false;" title="Voir l'image PIA00274: Io Glowing in the Dark sur le site de la NASA">Voir l'image PIA00274: Io Glowing in the Dark sur le site de la NASA.</a></div>
PIA00274: Io Glowing in the Dark
<h1>PIA00282: Io - Full Disk Centered on Media Regio</h1><div class="PIA00282" lang="en" style="width:700px;text-align:left;margin:auto;background-color:#000;padding:10px;max-height:150px;overflow:auto;"><p>The mottled face of Jupiter's volcanically active moon Io [pronounced 'EYE-oh' or 'EE-OH'], viewed by the camera onboard NASA's Galileo spacecraft, shows dramatic changes since it was seen 17 years ago by the exploratory NASA spacecraft Voyagers 1 and 2. This Galileo image, taken on June 25, 1996 at a range of 2.24 million kilometers (1.4 million miles), is centered on the Media Regio area and shows details of the volcanic regions and colored deposits that characterize Io. North is at the top of the picture and the Sun illuminates the surface from the east (right). The smallest features that can be discerned here are approximately 23 kilometers (14 miles) in size, a resolution comparable to the best Voyager images of this face of Io. Io's surface is covered with volcanic deposits that are thought to contain ordinary silicate rock, along with various sulfur-rich compounds that give the satellite its distinctive color. In the brighter areas the surface is coated with frosts of sulfur dioxide. Dark areas are regions of current or recent volcanic activity. Planetary scientists say many changes are evident in the surface markings since this region of Io was imaged 17 years ago by the Voyager spacecraft. The bright regions near the eastern limb of the moon are much more prominent in the Galileo images than they were previously. Surface details have also changed dramatically in the vicinity of the eruptive volcano Masubi (the large, predominantly white feature seen near the 6 o'clock position in this view). Masubi was discovered as an active volcano during the Voyager encounters of Io in 1979.<br /><br /><a href="http://photojournal.jpl.nasa.gov/catalog/PIA00282" onclick="window.open(this.href); return false;" title="Voir l'image PIA00282: Io - Full Disk Centered on Media Regio sur le site de la NASA">Voir l'image PIA00282: Io - Full Disk Centered on Media Regio sur le site de la NASA.</a></div>
PIA00282: Io - Full Disk Centered on Media Regio
<h1>PIA00292: Three Views of Io</h1><div class="PIA00292" lang="en" style="width:800px;text-align:left;margin:auto;background-color:#000;padding:10px;max-height:150px;overflow:auto;"><p>Three full-disk color views of Jupiter's volcanic moon Io as seen by NASA's Galileo spacecraft camera are shown in enhanced color (near-infrared-, green-, and violet-filtered images) to highlight details of the surface. Comparisons of these images to those taken by the Voyager spacecraft 17 years ago has revealed many changes have occurred on Io. Since that time, about a dozen areas at least as large as the state of Connecticut have been resurfaced. These three views, taken by Galileo in late June 1996, show about 75 percent of Io's surface. The images reveal that some areas on Io are truly red, whereas much of the surface is yellow or light greenish. The major red areas shown here appear to be closely associated with very recent fragmental volcanic deposits (pyroclastics) erupted in the form of volcanic plumes. The most prominent red oval surrounds the volcano Pele (far right), as previously discovered by Hubble Space Telescope images. An intense red spot lies near the active plume Marduk east of Pele. Other reddish areas are associated with known hot spots or regions that have changed substantially since the Voyager spacecraft flybys of 1979. The reddish deposits may be the products of high-temperature explosive volcanism. There are some curious differences in the overlap region between the images at left and center. There are several especially bright areas in the image at left that appear much darker in the image at center. These may represent transient eruptions or surface materials with unusual light-scattering properties. Several volcanic plumes active during the Voyager flybys in 1979 occurred near the bright limbs or terminator regions of these images, where airborne materials should be detectable. Loki and Amirani appear to be inactive, Volund is active, and Pele may be active but is extremely faint. The plume Marduk also seems to be active, and dark jets of erupting materials can be seen against the disk. Several previously unknown mountains can be seen near the terminators. The Galileo mission is managed by NASA's Jet Propulsion Laboratory.<br /><br /><a href="http://photojournal.jpl.nasa.gov/catalog/PIA00292" onclick="window.open(this.href); return false;" title="Voir l'image PIA00292: Three Views of Io sur le site de la NASA">Voir l'image PIA00292: Three Views of Io sur le site de la NASA.</a></div>
PIA00292: Three Views of Io
<h1>PIA00293: Eruption on Io</h1><div class="PIA00293" lang="en" style="width:800px;text-align:left;margin:auto;background-color:#000;padding:10px;max-height:150px;overflow:auto;"><p>This image, taken by NASA's Galileo spacecraft, shows a new blue-colored volcanic plume extending about 100 kilometers (about 60 miles) into space from Jupiter's moon Io (see inset at lower left). The blue color of the plume is consistent with the presence of sulfur dioxide gas and 'snow' condensing from the gas as the plume expands and cools. Galileo images have also shown that the Ra Patera plume glows in the dark, perhaps due to the fluorescence of sulfur and oxygen ions created by the breaking apart of sulfur dioxide molecules by energetic particles in the Jovian magnetosphere. The images at right show a comparison of changes seen near the volcano Ra Patera since the Voyager spacecraft flybys of 1979 (windows at right show Voyager image at top and Galileo image at bottom). This eruptive plume is an example of a new type of volcanic activity discovered during Voyager's flyby in 1979, believed to be geyser-like eruptions driven by sulfur dioxide or sulfur gas erupting and freezing in Io's extremely tenuous atmosphere. Volcanic eruptions on Earth cannot throw materials to such high altitudes. Ra Patera is the site of dramatic surface changes. An area around the volcano of about 40,000 square kilometers, area about the size of New Jersey, has been covered by new volcanic deposits. The image was taken in late June 28, 1996 from a distance of 972,000 kilometers (604,000 miles). The Galileo mission is managed by NASA's Jet Propulsion Laboratory.<br /><br /><a href="http://photojournal.jpl.nasa.gov/catalog/PIA00293" onclick="window.open(this.href); return false;" title="Voir l'image PIA00293: Eruption on Io sur le site de la NASA">Voir l'image PIA00293: Eruption on Io sur le site de la NASA.</a></div>
PIA00293: Eruption on Io
<h1>PIA00318: Io Shown in Lambertian Equal Area Projection and in Approximately Natural Color</h1><div class="PIA00318" lang="en" style="width:800px;text-align:left;margin:auto;background-color:#000;padding:10px;max-height:150px;overflow:auto;">Voyager 1 computer color mosaics, shown in approximately natural color and in Lambertian equal-area projections, show the Eastern (left) and Western (right) hemispheres of Io. This innermost of Jupiter's 4 major satellites is the most volcanically active object in the solar system. Io is 2263 mi (3640 km) in diameter, making it a little bigger than Earth's moon. Almost all the features visible here have volcanic origins, including several calderas and eruption plumes that were active at the time of the Voyager 1 encounter.<br /><br /><a href="http://photojournal.jpl.nasa.gov/catalog/PIA00318" onclick="window.open(this.href); return false;" title="Voir l'image PIA00318: Io Shown in Lambertian Equal Area Projection and in Approximately Natural Color sur le site de la NASA">Voir l'image PIA00318: Io Shown in Lambertian Equal Area Projection and in Approximately Natural Color sur le site de la NASA.</a></div>
PIA00318: Io Shown in Lambertian Equal Area Projection and in Approximately Natural Color
<h1>PIA00320: Loki Patera</h1><div class="PIA00320" lang="en" style="width:800px;text-align:left;margin:auto;background-color:#000;padding:10px;max-height:150px;overflow:auto;">A huge area of Io's volcanic plains is shown in this Voyager 1 image mosaic. Numerous volcanic calderas and lava flows are visible here. Loki Patera, an active lava lake, is the large shield-shaped black feature. Heat emitted from Loki can be seen through telescopes all the way from Earth. These telescopic observations tell us that Loki has been active continuously (or at least every time astronomers have looked) since the Voyager 1 flyby in March 1979. The composition of Io's volcanic plains and lava flows has not been determined, but they could consist dominantly of sulfur with surface frosts of sulfur dioxide or of silicates (such as basalts) encrusted with sulfur and sulfur dioxide condensates. The bright whitish patches probably consist of freshly deposited SO2 frost. The black spots, including Loki, are probably hot sulfur lava, which may remain molten by intrusions of molten silicate magma, coming up from deeper within Io. The ultimate source of heat that keeps Io active is tidal frictional heating due to the continual flexure of Io by the gravity of Jupiter and Europa, another of Jupiter's satellites.<br /><br /><a href="http://photojournal.jpl.nasa.gov/catalog/PIA00320" onclick="window.open(this.href); return false;" title="Voir l'image PIA00320: Loki Patera sur le site de la NASA">Voir l'image PIA00320: Loki Patera sur le site de la NASA.</a></div>
PIA00320: Loki Patera
<h1>PIA00321: Io, the Ra Patera, Mazda Catena, and Gibil Patera Area</h1><div class="PIA00321" lang="en" style="width:800px;text-align:left;margin:auto;background-color:#000;padding:10px;max-height:150px;overflow:auto;">Io's volcanic plains are shown in this Voyager 1 image mosaic. Also visible are numerous volcanic calderas and lava flows. Ra Patera with its multihued lava flows is below and right of the mosaic's center. This scene is about 1300 miles (2100 km) long. The composition of Io's volcanic plains and lava flows has not been determined, but they could consist dominantly of sulfur or of silicates (such as basalt) coated with sulfur condensates. The bright whitish patches probably consist of freshly deposited SO2 frost.<br /><br /><a href="http://photojournal.jpl.nasa.gov/catalog/PIA00321" onclick="window.open(this.href); return false;" title="Voir l'image PIA00321: Io, the Ra Patera, Mazda Catena, and Gibil Patera Area sur le site de la NASA">Voir l'image PIA00321: Io, the Ra Patera, Mazda Catena, and Gibil Patera Area sur le site de la NASA.</a></div>
PIA00321: Io, the Ra Patera, Mazda Catena, and Gibil Patera Area
<h1>PIA00323: Eruption of Pele</h1><div class="PIA00323" lang="en" style="width:800px;text-align:left;margin:auto;background-color:#000;padding:10px;max-height:150px;overflow:auto;">The eruption of Pele on Jupiter's moon Io. The volcanic plume rises 300 kilometers above the surface in an umbrella-like shape. The plume fallout covers an area the size of Alaska. The vent is a dark spot just north of the triangular-shaped plateau (right center). To the left, the surface is covered by colorful lava flows rich in sulfur.<br /><br /><a href="http://photojournal.jpl.nasa.gov/catalog/PIA00323" onclick="window.open(this.href); return false;" title="Voir l'image PIA00323: Eruption of Pele sur le site de la NASA">Voir l'image PIA00323: Eruption of Pele sur le site de la NASA.</a></div>
PIA00323: Eruption of Pele
<h1>PIA00324: Volcanic Plains of Io Near Galai Patera</h1><div class="PIA00324" lang="en" style="width:800px;text-align:left;margin:auto;background-color:#000;padding:10px;max-height:150px;overflow:auto;">Io's volcanic plains are shown in this Voyager 1 image, which spans an area about 1030 km (640 miles) from left to right. North is about the 1:30 position. Numerous volcanic calderas and lava flows are visible here. The brown teardrop-shaped feature at left center is Galai Patera, a 100-km-long (62 mi) lava-flooded caldera (collapsed vent) of a volcano. The composition of Io's volcanic plains and lava flows has not been determined. The prevalent yellow, brown, and orange material may consist dominantly of sulfur with surface frosts of sulfur dioxide or of silicates (such as basalt) encrusted with sulfur and sulfur dioxide condensates. The whitish patches probably are freshly deposited SO2 frost.<br /><br /><a href="http://photojournal.jpl.nasa.gov/catalog/PIA00324" onclick="window.open(this.href); return false;" title="Voir l'image PIA00324: Volcanic Plains of Io Near Galai Patera sur le site de la NASA">Voir l'image PIA00324: Volcanic Plains of Io Near Galai Patera sur le site de la NASA.</a></div>
PIA00324: Volcanic Plains of Io Near Galai Patera
<h1>PIA00327: Io, the South Polar Region</h1><div class="PIA00327" lang="en" style="width:800px;text-align:left;margin:auto;background-color:#000;padding:10px;max-height:150px;overflow:auto;">This Voyager 1 image mosaic shows Io's south polar region. The South Pole is near the terminator (line between daylight and night) at right center. Haemus Mons, a 10-km high (32,000 foot) mountain is at bottom. Elsewhere, much flatter volcanic plains, eroded volcanic plateaus, and crater-like volcanic calderas dominate the scene. The partly black-filled caldera at far left is Creidne Patera. The composition of the prevalent volcanic plains of Io could consist dominantly of sulfur with a thin discontinuous coating of sulfur dioxide frost or of silicates (such as basalt) coated with sulfurous condensates. The black material in Creidne Patera is where sulfur or silicates are probably still molten, whereas the brown material in the caldera is probably where the sulfur has solidified.<br /><br /><a href="http://photojournal.jpl.nasa.gov/catalog/PIA00327" onclick="window.open(this.href); return false;" title="Voir l'image PIA00327: Io, the South Polar Region sur le site de la NASA">Voir l'image PIA00327: Io, the South Polar Region sur le site de la NASA.</a></div>
PIA00327: Io, the South Polar Region