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

<h1>PIA02099: Thera and Thrace on Europa</h1><div class="PIA02099" lang="en" style="width:800px;text-align:left;margin:auto;background-color:#000;padding:10px;max-height:150px;overflow:auto;"><p>Thera and Thrace are two dark, reddish regions of enigmatic terrain that disrupt the older icy ridged plains on Jupiter's moon Europa. North is toward the top of the mosaic obtained by NASA's Galileo spacecraft. Thera (left) is about 70 kilometers wide by 85 kilometers high (43 by 53 miles) and appears to lie slightly below the level of the surrounding plains. Some bright icy plates which are observed inside appear to be dislodged from the edges of the chaos region. The curved fractures along its boundaries suggest that collapse may have been involved in Thera's formation. In contrast, Thrace (right) is longer, shows a hummocky texture, and appears to stand at or slightly above the older surrounding bright plains. Thrace abuts the gray band Libya Linea to the south and appears to darken Libya. One model for the formation of these and other chaos regions on Europa is complete melt-through of Europa's icy shell from an ocean below. Another model is that warm ice welled up from below and caused partial melting and disruption of the surface.</p><p>To produce this image, two regional images obtained at a resolution of 220 meters (240 yards) per picture element during Galileo's 17th orbit of Jupiter were colorized with lower resolution (1.4 kilometers or 1526 yards per picture element) images of the region obtained during the 14th orbit. The color image is generated from the violet, green, and near-infrared (968 nanometers) filters of the Galileo Solid State Imaging system and exaggerates the subtle color differences of Europa's surface. The mosaic, centered at about 50 degrees south latitude and 180 degrees longitude, covers an area approximately 525 by 300 kilometers (325 by 186 miles). The images from the 17th orbit were acquired at Universal Time 02 hours, 51 minutes, 56 seconds on September 26, 1998 when the sun illuminated the region from the northeast.</p><p>The Jet Propulsion Laboratory, Pasadena, CA manages the Galileo mission for NASA's Office of Space Science, Washington, DC.</p><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://solarsystem.nasa.gov/galileo/" target="_blank">http://solarsystem.nasa.gov/galileo/</a>. Background information and educational context for the images can be found 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/PIA02099" onclick="window.open(this.href); return false;" title="Voir l'image PIA02099: Thera and Thrace on Europa sur le site de la NASA">Voir l'image PIA02099: Thera and Thrace on Europa sur le site de la NASA.</a></div>
PIA02099: Thera and Thrace on Europa
<h1>PIA02528: Europa's Jupiter-Facing Hemisphere</h1><div class="PIA02528" lang="en" style="width:800px;text-align:left;margin:auto;background-color:#000;padding:10px;max-height:150px;overflow:auto;"><p>This 12-frame mosaic provides the highest resolution view ever obtained of the side of Jupiter's moon Europa that faces the giant planet. It was obtained by the camera onboard NASA's Galileo spacecraft on November 25, 1999 during the spacecrafts 25th orbit of Jupiter.</p><p>The new images have resolutions of about 1 kilometer (0.6 miles) per picture element. Lower resolution context was provided by images acquired during earlier Galileo orbits. In the earlier images, the resolution is 7 and 13 kilometers (4 and 8 miles) per picture element, respectively.</p><p>Numerous linear features in the center of the mosaic and toward the poles may have formed in response to tides strong enough to fracture Europa's icy surface. Some of these features extend for over 1,500 kilometers (900 miles). Darker regions near the equator on the eastern (right) and western (left) limb may be vast areas of chaotic terrain. Bright white spots near the western limb are the ejecta blankets of young impact craters.</p><p>North is to the top of the picture and the sun illuminates the surface from the left. The image, centered at 0 latitude and 10 longitude, covers an area approximately 2,500 by 3,000 kilometers. The finest details that can discerned in this picture are about 2 kilometers across (about 1,550 by 1,860 miles). The images were taken by Galileo's camera on November 25, 1999 when the spacecraft was 94,000 kilometers (58,000 miles) from Europa.</p><p>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.</p><p>This image and other images and data received from Galileo are posted on the Galileo mission home page at <a href="http://solarsystem.nasa.gov/galileo/" target="_blank">http://solarsystem.nasa.gov/galileo/</a>. Background information and educational context for the images can be found at <a href="http://solarsystem.nasa.gov/planets/profile.cfm?Object=Jup_Io" target="_blank">http://galileo.jpl.nasa.gov/gallery/io.cfm</a>.</p><br /><br /><a href="http://photojournal.jpl.nasa.gov/catalog/PIA02528" onclick="window.open(this.href); return false;" title="Voir l'image PIA02528: Europa's Jupiter-Facing Hemisphere sur le site de la NASA">Voir l'image PIA02528: Europa's Jupiter-Facing Hemisphere sur le site de la NASA.</a></div>
PIA02528: Europa's Jupiter-Facing Hemisphere
<h1>PIA02590: Europa's Frozen Surface</h1><div class="PIA02590" lang="en" style="width:536px;text-align:left;margin:auto;background-color:#000;padding:10px;max-height:150px;overflow:auto;"><p>Europa, a moon of Jupiter, appears as a thick crescent in this enhanced-color image from NASA's Galileo spacecraft, which has been orbiting Jupiter since 1995.<p>The view combines images taken in violet, green and near-infrared filters in 1998 and 1995. The colors have been stretched to show the subtle differences in materials that cover the icy surface of Europa. Reddish linear features are some of the cracks and ridges, thousands of kilometers long, which are caused by the tides raised by the gravitational pull of Jupiter. Mottled, reddish "chaotic terrain" exists where the surface has been disrupted and ice blocks have moved around. The red material at the ridges and chaotic terrain is a non-ice contaminant and could be salts brought up from a possible ocean beneath Europa's frozen surface.<p>Also visible are a few circular features, which are small impact craters. Europa's surface has very few craters, indicating that recent or current geologic activity has removed the traces of older impacts. The paucity of craters, coupled with other evidence, has led scientists to surmise that there could be an ocean of liquid water beneath Europa's surface. Where there is water, there could be life. This is why Europa is a target of current interest for study of the possibility of non-Earth life. A follow-up spacecraft to Galileo will be Europa Orbiter, which should determine whether or not Europa has an ocean.<p>While at the University of Arizona, Tucson, Dr. Cynthia Phillips used this image in a detailed search for current geologic activity on Europa. Phillips is currently with the SETI Institute, Mountain View, Calif. For a study published in the Journal of Geophysical Research -- Planets last year, she compared the frames that make up this image with similar images taken in 1979 by the Voyager spacecraft and found no sign of changes due to geologic activity. That suggests a minimum surface age for Europa of about 30 million years, though the result does not rule out current geologic activity altogether, as the study was limited by the resolution of 2 kilometers (1.6 miles) or more per pixel in this image and the Voyager images. Future images by Europa Orbiter may allow a search for smaller-scale changes on Europa's surface.<p>The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the Galileo and Voyager missions for NASA's Office of Space Science, Washington, D.C. Additional information about Galileo and its discoveries is available on the Galileo mission home page at <a href="http://solarsystem.nasa.gov/galileo/" target="_blank">http://solarsystem.nasa.gov/galileo/</a>.<br /><br /><a href="http://photojournal.jpl.nasa.gov/catalog/PIA02590" onclick="window.open(this.href); return false;" title="Voir l'image PIA02590: Europa's Frozen Surface sur le site de la NASA">Voir l'image PIA02590: Europa's Frozen Surface sur le site de la NASA.</a></div>
PIA02590: Europa's Frozen Surface
<h1>PIA02861: Europa and Callisto under the watchful gaze of Jupiter</h1><div class="PIA02861" lang="en" style="width:526px;text-align:left;margin:auto;background-color:#000;padding:10px;max-height:150px;overflow:auto;"><p>One moment in an ancient, orbital dance is caught in this color picture taken by NASA's Cassini spacecraft on Dec. 7, 2000, just as two of Jupiter's four major moons, Europa and Callisto, were nearly perfectly aligned with each other and the center of the planet.<p>The distances are deceiving. Europa, seen against Jupiter, is 600,000 kilometers (370,000 miles) above the planet's cloud tops. Callisto, at lower left, is nearly three times that distance from the cloud tops. Europa is a bit smaller than Earth's Moon and has one of the brightest surfaces in the solar system. Callisto is 50 percent bigger -- roughly the size of Saturn's largest satellite, Titan -- and three times darker than Europa. Its brightness had to be enhanced in this picture, relative Europa's and Jupiter's, in order for Callisto to be seen in this image.<p>Europa and Callisto have had very different geologic histories but share some surprising similarities, such as surfaces rich in ice. Callisto has apparently not undergone major internal compositional stratification, but Europa's interior has differentiated into a rocky core and an outer layer of nearly pure ice. Callisto's ancient surface is completely covered by large impact craters: The brightest features seen on Callisto in this image were discovered by the Voyager spacecraft in 1979 to be bright craters, like those on our Moon. In contrast, Europa's young surface is covered by a wild tapestry of ridges, chaotic terrain and only a handful of large craters.<p>Recent data from the magnetometer carried by the Galileo spacecraft, which has been in orbit around Jupiter since 1995, indicate the presence of conducting fluid, most likely salty water, inside both worlds.<p>Scientists are eager to discover whether the surface of Saturn's Titan resembles that of Callisto or Europa, or whether it is entirely different when Cassini finally reaches its destination in 2004. <p>Cassini is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the Cassini mission for NASA's Office of Space Science, Washington, D.C.<br /><br /><a href="http://photojournal.jpl.nasa.gov/catalog/PIA02861" onclick="window.open(this.href); return false;" title="Voir l'image PIA02861: Europa and Callisto under the watchful gaze of Jupiter sur le site de la NASA">Voir l'image PIA02861: Europa and Callisto under the watchful gaze of Jupiter sur le site de la NASA.</a></div>
PIA02861: Europa and Callisto under the watchful gaze of Jupiter
<h1>PIA02960: Folds on Europa</h1><div class="PIA02960" lang="en" style="width:800px;text-align:left;margin:auto;background-color:#000;padding:10px;max-height:150px;overflow:auto;">This image, acquired by NASA's Galileo spacecraft on September 26, 1998, shows features on the surface of Jupiter's moon Europa that a scientific report published today interprets as signs of compressive folding.<p>The imaged area is in the Astypalaea Linea region of Europa's southern hemisphere, seen with low-angle sunshine coming from the upper right. North is toward the top.<p>Astypalaea Linea is the smooth, gray area that stretches from north to south across the image mosaic. It is thought to have formed by a combination of pulling apart and sliding of the icy surface. The telltale fold features are within the smoother portions of the surface between the more dominant ridges, which are attributed to upwelling of material through surface ice. In the smooth areas, the surface has gentle swells and dips, which show most clearly in the version on the right, processed to accentuate broader-scale shapes. For example, a dip about 15 kilometers (about 10 miles) wide cuts diagonally across the northern half of the largest smooth area, and a rise runs parallel to that in the southern half of the smooth area.<br>closeup detail<p>Louise M. Prockter, at Johns Hopkins University, and Robert T. Pappalardo, at Brown University, report in the journal Science today that those rises, or anticlines, and dips, or synclines, appear to be the result of compression causing the crust to fold.<p>Additional evidence comes from smaller features more visible in the version on the left, covering the same area. At the crest of the gentle rise in the largest smooth area are small fractures that could be caused by the stretching stress of bending the surface layer upwards. Similarly, at the bottom of the adjacent dip are small, wrinkle-like ridges that could be caused by stress from bending the surface layer downwards.<p>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, Pasadena, Calif.<p><br /><br /><a href="http://photojournal.jpl.nasa.gov/catalog/PIA02960" onclick="window.open(this.href); return false;" title="Voir l'image PIA02960: Folds on Europa sur le site de la NASA">Voir l'image PIA02960: Folds on Europa sur le site de la NASA.</a></div>
PIA02960: Folds on Europa
<h1>PIA03002: Blocks in the Europan Crust Provide More Evidence of Subterranean Ocean</h1><div class="PIA03002" lang="en" style="width:800px;text-align:left;margin:auto;background-color:#000;padding:10px;max-height:150px;overflow:auto;"><p>The image on the left shows a region of Europa's crust made up of blocks which are thought to have broken apart and "rafted" into new positions. These features are the best geologic evidence to date that Europa may have had a subsurface ocean at some time in its past. Combined with the geologic data, the presence of a magnetic field leads scientists to believe an ocean is most likely present at Europa today. In this false color image, reddish-brown areas represent non-ice material resulting from geologic activity. White areas are rays of material ejected during the formation of the 25-km diameter impact crater Pwyll (see global view). Icy plains are shown in blue tones to distinguish possibly coarse-grained ice (dark blue) from fine-grained ice (light blue). Long, dark lines are ridges and fractures in the crust, some of which are more than 3,000 kilometers (1,850 miles) long. These images were obtained by NASA's Galileo spacecraft during September 7, 1996, December 1996, and February 1997 at a distance of 677,000 kilometers (417,489 miles).<br /><br /><a href="http://photojournal.jpl.nasa.gov/catalog/PIA03002" onclick="window.open(this.href); return false;" title="Voir l'image PIA03002: Blocks in the Europan Crust Provide More Evidence of Subterranean Ocean sur le site de la NASA">Voir l'image PIA03002: Blocks in the Europan Crust Provide More Evidence of Subterranean Ocean sur le site de la NASA.</a></div>
PIA03002: Blocks in the Europan Crust Provide More Evidence of Subterranean Ocean
<h1>PIA03878: Ruddy "Freckles" on Europa</h1><div class="PIA03878" lang="en" style="width:800px;text-align:left;margin:auto;background-color:#000;padding:10px;max-height:150px;overflow:auto;"><p>Reddish spots and shallow pits pepper the enigmatic ridged surface of Europa in this view combining information from images taken by NASA's Galileo spacecraft during two different orbits around Jupiter.<p>The spots and pits visible in this region of Europa's northern hemisphere are each about 10 kilometers (6 miles) across. The dark spots are called "lenticulae," the Latin term for freckles. Their similar sizes and spacing suggest that Europa's icy shell may be churning away like a lava lamp, with warmer ice moving upward from the bottom of the ice shell while colder ice near the surface sinks downward. Other evidence has shown that Europa likely has a deep melted ocean under its icy shell. Ruddy ice erupting onto the surface to form the lenticulae may hold clues to the composition of the ocean and to whether it could support life.<p>The image combines higher-resolution information obtained when Galileo flew near Europa on May 31, 1998, during the spacecraft's 15th orbit of Jupiter, with lower-resolution color information obtained on June 28, 1996, during Galileo's first orbit.<p>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 <a href="http://solarsystem.nasa.gov/galileo/" target="_blank">http://solarsystem.nasa.gov/galileo/</a>.<br /><br /><a href="http://photojournal.jpl.nasa.gov/catalog/PIA03878" onclick="window.open(this.href); return false;" title="Voir l'image PIA03878: Ruddy "Freckles" on Europa sur le site de la NASA">Voir l'image PIA03878: Ruddy "Freckles" on Europa sur le site de la NASA.</a></div>
PIA03878: Ruddy "Freckles" on Europa
<h1>PIA09246: Europa</h1><div class="PIA09246" lang="en" style="width:256px;text-align:left;margin:auto;background-color:#000;padding:10px;max-height:150px;overflow:auto;"><p>This image of Jupiter's icy moon Europa, the first Europa image returned by New Horizons, was taken with the spacecraft's Long Range Reconnaissance Imager (LORRI) camera at 07:19 Universal Time on February 27, from a range of 3.1 million kilometers (1.9 million miles). The longitude of the disk center is 307 degrees West and the image scale is 15 kilometers (9 miles) per pixel. This is one of a series of images designed to look for landforms near Europa's terminator — the line dividing day and night —where low Sun angles highlight subtle topographic features. </p><p>Europa's fractured icy surface is thought to overlie an ocean about 100 kilometers (60 miles) below the surface, and the New Horizons team will be analyzing these images for clues about the nature of the icy crust and the forces that have deformed it. Europa is about the size of Earth's moon, with a diameter of 3,130 kilometers (1.945 miles).</p><p>This is one of a handful of images of the Jupiter system already returned by New Horizons during its close approach to Jupiter. Most of the data being gathered by the spacecraft are stored onboard and will be downlinked to Earth during March and April 2007. </p><br /><br /><a href="http://photojournal.jpl.nasa.gov/catalog/PIA09246" onclick="window.open(this.href); return false;" title="Voir l'image PIA09246: Europa sur le site de la NASA">Voir l'image PIA09246: Europa sur le site de la NASA.</a></div>
PIA09246: Europa
<h1>PIA09361: Europa Rising</h1><div class="PIA09361" lang="en" style="width:800px;text-align:left;margin:auto;background-color:#000;padding:10px;max-height:150px;overflow:auto;"><p>New Horizons took this image of the icy moon Europa rising above Jupiter's cloud tops with its Long Range Reconnaissance Imager (LORRI) at 11:48 Universal Time on February 28, 2007, six hours after the spacecraft's closest approach to Jupiter.<p></p>The picture was one of a handful of the Jupiter system that New Horizons took primarily for artistic, rather than scientific, value. This particular scene was suggested by space enthusiast Richard Hendricks of Austin, Texas, in response to an Internet request by New Horizons scientists for evocative, artistic imaging opportunities at Jupiter.<p></p>The spacecraft was 2.3 million kilometers (1.4 million miles) from Jupiter and 3 million kilometers (1.8 million miles) from Europa when the picture was taken. Europa's diameter is 3,120 kilometers (1,939 miles). The image is centered on Europa coordinates 5 degrees south, 6 degrees west. In keeping with its artistic intent - and to provide a more dramatic perspective - the image has been rotated so south is at the top. </p><br /><br /><a href="http://photojournal.jpl.nasa.gov/catalog/PIA09361" onclick="window.open(this.href); return false;" title="Voir l'image PIA09361: Europa Rising sur le site de la NASA">Voir l'image PIA09361: Europa Rising sur le site de la NASA.</a></div>
PIA09361: Europa Rising