Jupiter: the "King" and His Moons |
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Io: surface deposits and craters35 visteThis 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 Mensa30 vistenessun commento
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Collapsing Cliff at Telegonus Mensa (MULTISPECTRUM; credits: Lunexit)16 visteCaption 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)".
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The eruption of "Pele" on Io38 vistenessun commento
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Tohill Mons40 vistenessun commento
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Tohill Mons: Volcanoes and Craters30 vistenessun commento
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The mysterious Tohill Mons and Patera (1) - natural colors22 vistenessun commento
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The mysterious Tohill Mons and Patera (2) - natural colors20 vistenessun commento
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Tohill Mons (MULTISPECTRUM-2; credits: Lunexit)17 visteCaption 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".
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Io: Tupan Patera53 visteWonderful colors in a volcanic crater named Tupan Patera on Jupiter's moon Io, as seen in this image from NASA's Galileo spacecraft, show varied results of lava interacting with sulfur-rich materials.
The colorfulness of the image is only slightly enhanced from what the human eye would see on the scene. The red in the image includes a small amount of infrared energy. Tupan Patera, named after a Brazilian thunder god, was seen as an active hot spot in earlier Galileo observations, but those low-resolution views did not show details of volcanic activity. This image taken in October 2001 at a resolution of 135 meters (443 feet) per picture element reveals the complex nature of the crater.
Tupan is now clearly shown to be a volcanic depression, about 75 kilometers (47 miles) across, surrounded by cliffs about 900 meters (3000 feet) tall. In the center is a large area that must be higher than the rest of the crater floor because it has not been covered by the dark lavas. Much of the area is coated with a diffuse red deposit that Galileo scientists believe has condensed from sulfur gas escaping from volcanic vents. The floor of Tupan is covered with a surreal pattern of dark black, green, red, and yellow materials. The black material is recent, still-warm lava. The yellow is presumed to be a mix of sulfurous compounds, and the green appears to form where red sulfur has interacted with the dark lavas. While Galileo scientists have found previous evidence for both molten sulfur and molten rock on Io, this image shows the best evidence to date of chemical reactions taking place between the two.
The intermingled patches of sulfur and lava are difficult to explain. The yellowish sulfur may be melting from within the crater walls over solidified but warm lava. The sulfur may boil away from the areas too hot for liquid sulfur to sit on, leaving patches where the dark lava is still visible.
North is to the top of the image and the Sun illuminates the surface from the upper right.
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Volcanic activity on Io ("Plumes" and "Flares")29 vistenessun commento
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Io: volcanic depression about 100 Km long, near the equator42 visteThis image taken by NASA's Galileo spacecraft on Oct. 16, 2001, near the equator of Jupiter's moon Io shows the contrast in volcanism styles found on Io.
The central feature is a large patera, or volcanic depression, almost 100 kilometers (60 miles) long. It may have formed after eruptions of lava emptied a subsurface magma chamber and left an empty space into which the crust collapsed. Evidence of lava flows associated with this patera, however, is difficult to find. Either the flows have been buried, or perhaps they never erupted and simply drained back deep into the crust.
On the right of the image is a small shield volcano, similar to volcanoes in Hawaii. It is rare for lavas on Io to be thick enough to pile up into shields around vents. They usually run out in thin, long flows instead. This shield abuts some very pale lava flows that emerged from a small vent to the west. These flows could be made of sulfur, like flows at Io's Emakong Patera. The vent is also surrounded by dark, diffuse material, which may be the result of lava erupted in an explosive, gas-rich eruption, similar to the 1980 eruption of Mount Saint Helens in Washington.
North is to the top of the image and the illumination is from the right. The image has a resolution of 330 meters (1,080 feet) per picture element and is 340 (211 miles) kilometers across.
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