Jupiter: the "King" and His Moons
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Io-SouthernLimbandlight-PIA02250.jpgThe Southern limb of Io58 visitenessun commentoMareKromium
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Io-Sulphur volcanism-PIA03887_modest.jpgPotential Source of Sulphur Flow on Io64 visiteA field of bright lava flows next to a shield volcano could be a source of recent sulfur volcanism on Io, as detected by instruments aboard NASA's Galileo spacecraft.
The mosaic at left combines higher-resolution images (330 meters or about 1080 feet per picture element) taken in October 2001 with lower-resolution color images (1.4 kilometers or 0.9 mile per picture element) taken in July 1999 by Galileo's solid-state imaging camera.
By comparing these images with a map of hot spots taken in February by Galileo's near-infrared mapping spectrometer (lower right), Galileo scientists noted that a new hot spot west of the active volcano Prometheus became bright in February 2000 and dimmed later. This hot spot appears to correspond with the bright flow field just west of a recently discovered shield volcano (see PIA03532), which is the only fresh volcanic material in the area.
The relatively low intensity of the February 2000 hot spot in the infrared data suggests a low-temperature eruption, consistent with sulfur lava rather than silicate lava as found elsewhere on Io and also on Earth. Sulfur lavas are thought to cool to a gray-yellow color on Io, as seen in the new flow field visible in the camera image. This bright flow field could be the best example of active sulfur lava flows deposited on Io during the Galileo mission. At upper right is a global view of Io showing the location of the more-detailed images.
The low temperature of this hot spot differs from many of Io's other active volcanoes, such as Pele, Tvashtar and Prometheus. Intense tidal flexing of Io helps keep the moon's interior molten, at some places producing silicate lavas hotter than any seen on Earth in billions of years. Io has the greatest known diversity of volcanic activity in the solar system.
North is to the top of all these images.
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Io-Sulphur_Volcanism-Original_NASA_Galileo.jpgRecent Sulphur Volcanism on Io (natural colors)53 visitenessun commento
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Io-Surface deposits and craters-PIA01514.jpgIo: surface deposits and craters59 visiteThis picture of Io, the innermost Galilean satellite, was taken by Voyager 1 on the morning of March 5, 1979 at a range of 377,000 kilometers (226,200 miles). The smallest features visible are about 10 kilometers (6 miles) across. The reddish, white and black areas are probably surface deposits, possibly consisting of mixtures of salts, sulfur and sublimate deposits of possible volcanic origin. Many of the black spots in these pictures are associated with craters of possible volcanic origin. The lack of impact craters on Io suggests that the surface is relatively young compared to the other Galilean satellites and some of the terrestrial planets such as Mercury and the Moon.
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Io-Telegonus Mensa-PIA03528_modest.jpgIo: Telegonus Mensa53 visitenessun commento
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Io-TelegonusMensa-PIA03528_modest.jpgCollapsing Cliff at Telegonus Mensa (MULTISPECTRUM; credits: Lunexit)54 visiteCaption NASA:"This mosaic, showing an area called Telegonus Mensa, on Jupiter's moon Io and obtained by using frames taken by the NASA's Galileo Spacecraft on Oct. 16, 2001, reveal a complex interplay of geologic processes.
Four small, HR frames (9,6 mt, or 32 feet, per picture element) have been set into the larger context mosaic, which has a resolution of 42 mt (140 feet) per picture element. The illumination is from the upper right and North is to the top of the mosaic. A fracture runs North-West from the lower right corner of the mosaic into the amphitheater in the center of the frame. A HR image along this fracture reveals that lava has erupted from it.
The amphitheater itself is the site of extensive erosion, as the cliff has slumped South-Eastward under the influence of Io's gravity. HR frames directly south of the amphitheater show another slumping cliff in detail. Flat tops of massive slump blocks — up to 6 Km (3,7 miles) long and 0,5 Km (0,3 miles) across — are illuminated by the the Sun and cast shadows down the face of the cliff.
Based on these shadows, Galileo scientists estimate that the cliff is 1 to 2 Km high.
Just to the left of center a series of landslides can be seen, the longest of which extends for about 4 Km (such as approx. 2,5 miles)".MareKromium
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Io-The eruption of Pele-PIA00323.jpgThe eruption of "Pele" on Io54 visitenessun commento
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Io-Tohill Mons-PIA03600_modest.jpgTohill Mons54 visitenessun commento
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Io-Tohill Volcanoes-dtlmgnf-PIA03527_modest.jpgTohill Mons: Volcanoes and Craters53 visitenessun commento
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Io-Tohill-Scarp-00.jpgThe mysterious Tohill Mons and Patera (1) - natural colors54 visitenessun commento
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Io-Tohill-Scarp-01.jpgThe mysterious Tohill Mons and Patera (2) - natural colors53 visitenessun commento
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Io-TohillMons-PIA03600_1.jpgTohill Mons (MULTISPECTRUM-2; credits: Lunexit)56 visiteCaption NASA:"Dramatic shadows across a mountainous landscape on Jupiter's moon Io reveal details of the topography around a peak named Tohil Mons in this mosaic created from images taken by NASA's Galileo Spacecraft in October 2001.
Tohil Mons rises 5,4 Km (18.000 feet) above Io's Surface, according to analysis of stereo imaging from earlier Galileo flybys of Io. The new images, with a resolution of 327 mt (1070 feet) per picture element, were taken when the Sun was low in the sky, producing informative shadows. North is to the top and the Sun illuminates the Surface from the upper right. The topographic features revealed include a very straight ridge extending South-West from the peak, 500- to 850-meter-high (1640- to 2790-foot-high) cliffs to the North-West and a curious pit immediately East of the peak.
Major questions remain about how Io's mountains form and how they are related to Io's ubiquitous volcanoes. Although Io is extremely active volcanically, few of its mountains appear to be volcanoes. However, two volcanic craters do lie directly to the North-East of Tohil's peak, a smaller dark-floored one and a larger one at the very edge of the mosaic. Furthermore, the shape of the pit directly East of the peak suggests a volcanic origin.
Galileo scientists will use these images to investigate the geologic history of Tohil Mons and its relationship to the neighboring volcanic features.
The image is centered at 28° South Latitude and 161° West Longitude".
MareKromium
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