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| Risultati della ricerca nelle immagini - "Jovian" |
Callisto-PIA00080-PCF-LXTT-IPF.jpgClosing-up on Valhalla (Absokute Natural Colors; credits for the additional process. and color.: Dr Paolo C. Fienga/Lunar Explorer Italia/Italian Planetary Foundation)67 visiteCallisto was revealed by the NASA - Voyager 1 cameras to be a heavily cratered and - most likely (as it was thought at that time) - geologically inactive Celestial Body. This mosaic of Voyager 1 images, obtained at a distance of about 400,000 Km (about 248.000 miles) from Callisto, shows Surface details as small as 10 Km (such as 6,2 miles) across. The largest Impact Features on the Callistoan Surface are the so-called "Multi-Ring Impact Basins"; two of them are enormous and Valhalla - the prominent Impact Feature visible here, in today's APOD - is the largest one, with a Bright Central Region approx. 600 Km (a little more than 372 miles) in diameter, and Rings extending as far as about 1800 Km (approx. 1118 miles) from the center. The second largest Impact Multi-Ring Basin is named Asgard, and it measures about 1600 Km (a little more than 993 miles) in diameter.
Multi-Ring Impact Structures probably originated as a result of a Post-Impact Concentric Fracturing of the Lithosphere lying on a layer of soft or - maybe - even Liquid Material: possibly, an Ocean. Last, but not least, in our opinion, as IPF, the remarkable resemblances existing between the Callistoan Valhalla Crater and the Tyre Crater, located on the other Jovian moon Europa, (*) may tell us, in the end, VERY similar stories about these two mysterious Celestial Bodies. Stories that may talk about worlds that, certainly a long, long time ago, were completely (or almost completely) covered by water. Stories that should also tell us something about what could still be happening, even now, up there: in the depths of Callisto, Europa and, maybe, of a few other Celestial Objects orbiting around the four Gas-Giant Planets of the Solar System...
(*) note: if you want to take a look at Tyre Crater, please refer to the APOD of January, 29, 2013
The Catenae, on the other hand (for example the Gomul Catena), are long Chains of Impact Craters lined up in straight lines across the Surface of Callisto. They were probably created by objects that were tidally disrupted as they passed close to Jupiter prior to the impact on Callisto, or by very oblique Impacts.
This frame (which is an Original NASA - Voyager 1 Spacecraft false color image mosaic published on the NASA - Planetary Photojournal with the ID n. PIA 00080) has been additionally processed and then re-colorized, according to an educated guess, by Dr Paolo C. Fienga (LXTT-IPF), in Absolute Natural Colors (such as the colors that a human eye would actually perceive if someone were onboard the NASA - Voyager 1 Spacecraft and then looked outside, towards the Jovian moon Callisto), by using an original technique created - and, in time, dramatically improved - by the Lunar Explorer Italia Team. Different colors, as well as different shades of the same color, mean, among others, the existence of different Elements present on the Surface of Callisto, each having a different Albedo (---> Reflectivity) and Chemical Composition.MareKromium
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Callisto-PIA02277-PCF-LXTT-IPF.jpgValhalla! (Absokute Natural Colors; credits for the additional process. and color.: Dr Paolo C. Fienga/Lunar Explorer Italia/Italian Planetary Foundation)73 visiteThis picture of the gigantic Multi-Ring Impact Basin named "Valhalla" and located on the Jovian moon Callisto, was taken by the NASA - Voyager 1 Spacecraft in the morning of March 6, of the AD 1979, at a distance of about 200.000 Km (such as approx. 124.000 miles) from the Surface of the farthermost of the 4 (four) so-called "Galilean" Natural Satellites (or moons) of the Gas-Giant Planet Jupiter. The complicated Circular Structure which characterizes Valhalla is, in a way (and according to NASA), relatively similar to other large Circular Impact Basins that can be seen on the Surface of the Earth's Moon as well as on the Planet Mercury but, as we already wrote and underlined in the past, we, as IPF, do believe that a true and strong resemblance between Valhalla and another Multi-Ring Impact Basin can only be found with the huge Tyre Crater; a Multi-Ring Impact Crater that is located, as you know, on the Jovian moon Europa.
Usually, the inner portions of these Multi-Ring Impact Basins are generally surrounded by Radially Lineated Ejecta and several Concentric Mountainous Ring Structures, which are thought to have formed during the Impact Event itself. However, the Callistoan Valhalla Multi-Ring Impact Basin consists of a Light-Floored Central Basin, that is approx. 300 Km (such as a little more than 186 miles) in diameter, surrounded by at least 8 (eight) to 10 (ten) discontinuous and rhythmically spaced Ridges, but no Radially Lineated Ejecta can be seen. In any case, the great number of Rings observed around Valhalla is a fact which is consistent with the hypothesis that Callisto possesses a very low Planetary Density and, also, a low internal strength. Furthermore, if you look carefully on the upper right side of the frame, at about 2 o'clock, a beautiful and extremely long and regular Catena (---> Chain of Craters, probably originated by a Cometary Strike or a Meteor that was heavily fragmented at the time of the Impact) can be seen.
This frame (which is an Original NASA - Voyager 1 Spacecraft b/w image published on the NASA - Planetary Photojournal with the ID n. PIA 02277) has been additionally processed and then colorized, according to an educated guess, by Dr Paolo C. Fienga (LXTT-IPF), in Absolute Natural Colors (such as the colors that a human eye would actually perceive if someone were onboard the NASA - Voyager 1 Spacecraft and then looked outside, towards the Jovian moon Callisto), by using an original technique created - and, in time, dramatically improved - by the Lunar Explorer Italia Team. Different colors, as well as different shades of the same color, mean, among others, the existence of different Elements present on the Surface of Callisto, each having a different Albedo (---> Reflectivity) and Chemical Composition.MareKromium
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Callisto-PIA03456-PCF-LXTT-IPF.jpgApproaching Callisto (Absolute Natural Colors; credits for the additional process. and color.: Dr Paolo C. Fienga/Lunar Explorer Italia/Italian Planetary Foundation)71 visiteBright scars on a darker Surface testify to a long history of impacts on the Jovian moon Callisto, as it can be seen in this image obtained by the NASA - Galileo Spacecraft. The picture, taken in May 2001, is the only complete global Absolute Natural Color image of Callisto ever obtained by the NASA - Galileo Spacecraft, which orbited around Jupiter from December, 7, of the AD 1995 and until September 21, of the AD 2003, when the Spacecraft was destroyed during a controlled impact with Jupiter itself.
Of Jupiter's 4 (four) largest moons (also known as the "Galilean Moons"), Callisto orbits farthest from the Giant Gas Planet. Furthermore, Callisto's Surface is uniformly cratered but, as you can see for yourself, is not uniform in color or brightness at all. At present day, Planetary Scientists believe that the brighter areas are mainly Ice while the darker ones should be made of highly eroded (and Ice-poor) Rocky Materials.
This frame (which is an Original NASA - Galileo Spacecraft color frame published on the NASA - Planetary Photojournal with the ID n. PIA 03456) has been additionally processed and then re-colorized, according to an educated guess, by Dr Paolo C. Fienga (LXTT-IPF), in Absolute Natural Colors (such as the colors that a human eye would actually perceive if someone were onboard the NASA - Galileo Spacecraft and then looked outside, towards the Jovian moon Callisto), by using an original technique created - and, in time, dramatically improved - by the Lunar Explorer Italia Team. Different colors, as well as different shades of the same color, mean, among others, the existence of different Elements present on the Surface of Callisto, each having a different Albedo (---> Reflectivity) and Chemical Composition.MareKromium
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Europa-Craters-Mannann_an_Crater-PIA01402-PCF-LXTT-IPF.jpgFeatures of Mannann'an Crater (Absolute Natural Colors; credits for the additional process. and color.: Dr Paolo C. Fienga/Lunar Explorer Italia/Italian Planetary Foundation)152 visiteThis composite view taken by the NASA - Galileo Spacecraft, shows a portion of the Rim and the Interior of the Impact Crater known as Mannann'an, which is located on Jupiter's moon, Europa. A high resolution image (20 meters per picture element) was combined with a lower resolution one (80 meters per picture element), to produce this composite picture. The color data here can be used to distinguish between Regions where the Ice located on the Surface of Europa is purer (---> cleaner) from other areas where the Ice itself, instead, is more contaminated (---> dirty; mixed with other elements); the reddish/brown Surface Material visible to the West (Left side - Sx) of the frame is thought to be "dirty" Ice, while the white/bluish areas visible inside the Crater should be made of "cleaner" Ice. The Rim of Mannann'an is (barely visible) on the left of the composite, approx. at the boundary between the area with the higher concentration of reddish/brown Surface Material and the area where the white Surface Material is dominant. The high resolution data show several small Surface Features inside this Impact Crater, including Concentric Fractures and a Spider-like set of Fractures near the right (East) edge of the image.
North is to the top of the picture and the Sun illuminates the scene from the East (right - Dx). The image, which is centered at 3° North Latitude and 240° West Longitude, covers an area of approximately 18 by 4 Km (such as about 11,12 by 2,48 miles). The finest details that can be discerned in this picture are about 40 meters (44 yards) across. The images were taken by the Solid State Imaging Camera onboard Galileo, when the Spacecraft flew by Europa on March 29th, 1998, at a distance of 1934 Km (such aapprox. 1201 miles) from its Surface.
This frame (which is an Original NASA - Galileo Spacecraft false colors image composite published on the NASA - Planetary Photojournal with the ID n. PIA 01402) has been additionally processed and then re-colorized, according to an educated guess carried out by Dr Paolo C. Fienga (LXTT-IPF), in Absolute Natural Colors (such as the colors that a human eye would actually perceive if someone were onboard the NASA - Galileo Spacecraft and then looked outside, towards the Surface of the Jovian moon Europa), by using an original technique created - and, in time, dramatically improved - by the Lunar Explorer Italia Team. Different colors, as well as different shades of the same color, mean, among others, the existence of different Elements present on the Surface of Europa, each having a different Albedo (---> Reflectivity) and Chemical Composition.MareKromium
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Europa-Craters-Tyre_Crater-PIA00702-PCF-LXTT-IPF.jpgTyre Crater (Absolute Natural Colors; credits for the additional process. and color.: Dr Paolo C. Fienga/Lunexit Team/Italian Planetary Foundation)141 visiteThis unbelievably complex Surface Feature located on the Jovian moon Europa was originally seen as a dark, diffuse Circular Patch on a previous NASA - Galileo Spacecraft's global image of Europa's Leading Hemisphere taken on April 3, 1997. The "Bulls-Eye" pattern appears to be a 140- Km-wide Impact "Scar" (about the size of the island of Hawaii) which formed as the Surface of Europa fractured minutes after a (probably) mountain-sized Asteroid or Comet slammed into this fascinating Celestial Body.
This approx. 214-Km-wide picture is the product of the combination of 3 (three) images which have originally been processed in false colors, so to enhance shapes and compositions of the photographed Surface. North is toward the top of this picture, which is illuminated from Sunlight coming from the West. This composite reveals a sequence of events which have deeply modified the Surface of Europa. The earliest event was the impact which formed the Tyre Structure, located at 34° North Latitude and 146,5° West Longitude. The impact was then followed by the formation of the brown/reddish lines superposed on Tyre. The brown/reddish color, in fact, designates areas that are probably made of (or covered by) some kind of a "dirty" Water-Ice Mixture. On the other hand, the fine light blue-gray lines crossing the whole Region from West to East appear to be Ridges which (obviously) formed after the Crater.
The images forming this composite were taken on April 4, 1997, at a resolution of 595 meters (1950 feet) per picture element and a range of approx. 29.000 Km (such as about 18.000 miles) from Europa. The frames were taken by Galileo's Solid State Imaging (CCD) System.
This frame (which is the Original NASA - Galileo Spacecraft false-color image composite published on the NASA - Planetary Photojournal with the ID n. PIA 00702) has been additionally processed and then re-colorized, according to an educated guess carried out by Dr Paolo C. Fienga (LXTT-IPF), in Absolute Natural Colors (such as the colors that a human eye would actually perceive if someone were onboard the NASA - Galileo Spacecraft and then looked outside, towards the Surface of the Jovian moon Europa), by using an original technique created - and, in time, dramatically improved - by the Lunar Explorer Italia Team. Different colors, as well as different shades of the same color, mean, among others, the existence of different Elements present on the Surface of Europa, each having a different Albedo (---> Reflectivity) and Chemical Composition.MareKromium
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Europa-Ice_Floes-PIA00578-PCF-LXTT-IPF.jpgEuropa's Ice Floes (Absolute Natural Colors; credits for the additional process. and color.: Dr Paolo C. Fienga/Lunexit Team/Italian Planetary Foundation)128 visiteJupiter's moon Europa, as seen in this image taken on June 27, 1996 by the NASA - Galileo Spacecraft, displays a few Surface Features that, in some areas, seem to resembe to Ice Floes (---> usually large, flat, and free masses of floating Sea Ice ) seen in the Polar Seas of our Home Planet Earth. Europa, which is about the size of Earth's Moon, possesses an Icy Crust that has been severely fractured, as indicated by the dark linear, curved, and wedged-shaped bands seen here. These Fractures have broken the Crust into Plates which are as large as 30 Km (such as about 18,6 miles) across. The Areas between the Plates are filled with Material that is probably Icy "Slush", contaminated with Rocky Debris. Some individual Plates were separated and rotated into new positions. Europa's density indicates that this Celestial Body has a shell of Water Ice thicker than approx. 100 Km (such as about 62 miles), parts of which could be liquid. Currently, Water Ice could extend from the Surface down to the Rocky Interior of Europa, but the Features seen in this image suggest that the motion of the disrupted Icy Plates was lubricated by soft Ice or perhaps liquid Water that was just below the Surface at the time of disruption.
This image covers part of the Equatorial Zone of Europa and was taken from a distance of approx. 156.000 Km (such as about 96.876 miles) by the Solid-State Imaging Subsystem onboard the NASA - Galileo Spacecraft. North is up and the Sun is nearly directly overhead. The area shown here is about 510 by 989 Km (such as approx. 317-by-614 miles), and the smallest visible Surface Feature is about 1,6 Km (approx. 1 mile) across.
This frame (which is the Original NASA - Galileo Spacecraft b/w image published on the NASA - Planetary Photojournal with the ID n. PIA 00578) has been additionally processed and then colorized, according to an educated guess carried out by Dr Paolo C. Fienga (LXTT-IPF), in Absolute Natural Colors (such as the colors that a human eye would actually perceive if someone were onboard the NASA - Galileo Spacecraft and then looked outside, towards the Surface of the Jovian moon Europa), by using an original technique created - and, in time, dramatically improved - by the Lunar Explorer Italia Team. Different colors, as well as different shades of the same color, mean, among others, the existence of different Elements present on the Surface of Europa, each having a different Albedo (---> Reflectivity) and Chemical Composition.MareKromium
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Europa-Lineae-Minos_Linea-PIA00275.jpgEuropa: Minos Linea (an EDM in possible Absolute Natural Colors; credits for the additional process. and color.: Dr Paolo C. Fienga - Lunexit Team)138 visitenessun commentoMareKromium
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Europa-Ridges-PIA17737-PCF-LXTT-IPF-1.jpgFeatures of Europa (Absolute Natural Colors; credits for the additional process. and color.: Dr Paolo C. Fienga/Lunar Explorer Italia/Italian Planetary Foundation)89 visiteThis image, taken by the NASA - Galileo Spacecraft on February, 2, 1999, shows us huge Cracks and Ridges on the Surface of the Jovian moon Europa. These (absolutely fascinating) Features reveal a complex Geologic History of Europa. Some Ridges, such as the prominent one, at the top right of the frame, develop into several long, arc-shaped "Cycloids" (---> a Cycloid is the curve traced by a point on the rim of a circular wheel as the wheel rolls along a straight line), that could reasonably be related to the changing Tidal Forces as Europa orbits the Gas-Giant Planet Jupiter. The Wall of this Ridge stands perhaps a third of a mile (approx. 0,5 Km) above the surrounding Ridged Plains, although their Edges are - likely - NOT as steep as they appear in this view.
The view was captured by the NASA - Galileo Spacecraft on February 2, 1999, during its E19 orbit, when the spacecraft was about 2500 miles (such as approx. 4023 km) from the Surface of Europa. The Resolution in the scene is roughly 295 feet (such as approx. 89.91 meters) per pixel. North is toward bottom left side of the picture.
This frame (which is a crop taken from an Original NASA - Galileo Spacecraft enhanced color image published on the NASA - Planetary Photojournal with the ID n. PIA 17737) has been additionally processed, contrast enhanced, magnified to aid visibility of the Surface details and then re-colorized, according to an educated guess carried out by Dr Paolo C. Fienga/LXTT/IPF, in what they should be its Absolute Natural Colors (such as the colors that a human eye would actually perceive if someone were onboard the NASA - Galileo Spacecraft and then looked outside, towards the Surface of the Jovian moon Europa), by using an original technique created - and, in time, dramatically improved - by the Lunar Explorer Italia Team. Different colors, as well as different shades of the same color, mean, among others, the existence of different Elements present on the Surface of Europa, each having a different Albedo (---> Reflectivity) and Chemical Composition.
Note: it is possible (but we, as IPF, have no way to be one-hundred-percent sure of such a circumstance), that the actual luminosity of Europa- as it is in this frame - would appear, to an average human eye, a little bit lower than it has been shown (or, better yet: interpreted) here.MareKromium
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Ganymede-V1-PIA02233-PCF-LXTT-IPF.jpgFeatures of Ganymede (Absolute Natural Colors; credits for the additional process. and color.: Dr Paolo C. Fienga/Lunar Explorer Italia/Italian Planetary Foundation)88 visiteThis frame was acquired by the NASA - Voyager 1 Spacecraft during its approach to Ganymede, from a distance of about 272.000 Km; the center of the picture lies at approx. 13° North Latitude and and 359° East Longitude. Ganymede (also known as Jupiter III) is the largest moon in the Solar System and the seventh moon (and third Galilean Satellite) outward from the Gas-Giant Planet Jupiter. Completing an orbit in roughly 7 (seven) Earth days, Ganymede participates in a 1:2:4 Orbital Resonance with the other Jovian moons Europa and Io, respectively. Ganymede has a diameter of about 5268 km (such as approx. 3273 miles), and, even though Ganymede is something like 8% larger than the planet Mercury, it only has about 45% of Mercury's mass; furthermore, its diameter is about 2% larger than the one of the Saturnian moon Titan, which is the second largest moon in the Solar System. Ganymede also has the highest mass of all Planetary Satellites, with approx. 2,02 times the mass of the Earth's Moon. This image shows detail on the Surface of Ganymede with a resolution of approx. 4,5 Km per pixel. What we see here, is a portion of a Region of Ganymede located in its Northern Hemisphere, near the Terminator. It shows a variety of Impact Structures, including both Rayed and Unrayed Impact Craters, as well as some odd-looking, Groove-like Surface Features (already discovered by the NASA - Voyager 1 Spacecraft in the lighter Regions of this Jovian moon). The most striking Surface Features, however, are the Bright Rayed Impact Craters which show a distinct light blueish color that, to some Observer, may also also appear white, with pink nuances, against the darker background. Ganymede's Surface is known to contain large amounts of Surface Water Ice and it appears that these (relatively) young Craters might have spread bright and (always relatively speaking) fresh Ice Materials all over the place. Likewise, the lighter color and Albedo (---> reflectivity) of the Grooved Areas suggests that over there, too, some cleaner and fresh Water Ice Material can be found. In fact, and as far as we know at the present day, Ganymede is composed of approximately equal amounts of Silicate Rock and Water Ice. It is a fully differentiated Celestial Body with an Iron-rich and still liquid core. Very recent studies suggest that, just like it has been speculated about the other Jovian moon Europa, even Ganymede may host a Subterranean Ocean, nearly 200 Km below its frozen Surface, somehow "sandwiched" between several different Layers of Rock and Ice. In addition to the above, the Surface of Ganymede is composed of two main types of Terrain: the Dark Terrain, saturated with Impact Craters and dated up to 4 (four) Billion Years ago (a Terrain that covers about a third of the moon), and the Lighter Terrain, which is crosscut by extensive Grooves and Ridges and that could be, likely, much less ancient. The cause of the Light Terrain's so-called "Disrupted Geology" is not yet fully known, but it could reasonably be the result of some powerful Tectonic Activity brought about by Tidal Heating (and let us not forget that Tidal Heating - due to Tidal Friction - may also be the primary reason why a Liquid Ocean can exist, deep down and inside the otherwise Frozen Crust of Ganymede). The NASA - Voyager 1 Spacecraft Original b/w frame has been additionally processed and then colorized, according to an informed speculation carried out by Dr Paolo C. Fienga (LXTT-IPF), in Absolute Natural Colors (such as the colors that a human eye would actually perceive if someone were onboard the NASA - Voyager 1 Spacecraft and then looked outside, towards the Jovian moon Ganymede), by using an original technique created - and, in time, dramatically improved - by the Lunar Explorer Italia Team. Different colors, as well as different shades of the same color, mean, among others, the existence of different Elements present on the Surface of Ganymede, each having a different Albedo (---> Reflectivity) and Chemical Composition.MareKromium
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Ganymede-V1-PIA02278-PCF-LXTT-IPF.jpgFeatures of Ganymede (Absolute Natural Colors; credits for the additional process. and color.: Dr Paolo C. Fienga/Lunar Explorer Italia/Italian Planetary Foundation)81 visiteThis picture of Ganymede was taken by the NASA - Voyager 1 Spacecraft on the afternoon of March 5, 1979, from a range of about 253.000 Km (such as approx. 151.800 miles). The picture, that is centered at about 66° South Latitude and 3° East Longitude, shows a portion of the South Western Limb Region of Ganymede. The smallest visible Surface Features are about 2,5 Km (roughly 1,5 miles) across. The Surface of this moon shows numerous ancient Impact Craters, many of which - like we have recently seen on Planet Mercury , thanks to the NASA - Messenger Spacecraft and Orbiter - have extensive Bright Ray Systems. The light Bands that we can see crossing the whole Surface of Ganymede contain alternating bright and dark lines which, probably, represent deformation of the Icy Material that form them. Despite the NASA - Voyager 1 Spacecraft data, some evidence relevant to the existence of a tenuous Oxygen-based Atmosphere (---> a so-called "Exosphere") on Ganymede (an Exhosphere which, by the way, very similar to the one found on the other Jovian moon Europa), was discovered by the Hubble Space Telescope (HST) in the AD 1995. The HST actually observed an Airglow of Atomic Oxygen in the far-UltraViolet at the wavelengths of 130,4 and 135,6 nanometers. Such an Airglow is excited when Molecular Oxygen gets dissociated by way of Electron Impacts (and that phenomenon is a further evidence about the existence of a significant Neutral Atmosphere around Ganymede, which is predominantly composed of O2 molecules). The Oxygen, however, is not a direct evidence of the presence, on Ganymede, of some possible Earth-like Lifeforms; as a matter of fact, the Oxigen that we find in the Atmosphere of this huge moon, is thought to be produced the when Water Ice that is largely present on the Surface of Ganymede gets split into Hydrogen and Oxygen through the action of Radiation, with the Hydrogen being more rapidly lost in the circum-Ganymedian Space due to its low Atomic Mass. Furthermore, the Airglow observed over Ganymede is not spatially homogeneous like the one existing over Europa. The HST also observed two bright spots located in the Northern and Southern Hemispheres of Ganymede, near ± 50° of Latitude, which is exactly the Boundary Region between the Open and the Closed Field Lines of the Ganymedian Magnetosphere. These bright spots, according to our present day knowledge, could have probably been tWO Ganymedian Polar Auroras, caused by Plasma Precipitation along the Open Field Lines of its Magnetosphere. The NASA - Voyager 1 Spacecraft Original b/w frame has been additionally processed and then colorized, according to an informed speculation carried out by Dr Paolo C. Fienga (LXTT-IPF), in Absolute Natural Colors (such as the colors that a human eye would actually perceive if someone were onboard the NASA - Voyager 1 Spacecraft and then looked outside, towards the Jovian moon Ganymede), by using an original technique created - and, in time, dramatically improved - by the Lunar Explorer Italia Team. Different colors, as well as different shades of the same color, mean, among others, the existence of different Elements present on the Surface of Ganymede, each having a different Albedo (---> Reflectivity) and Chemical Composition.MareKromium
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Io-Galai_Patera-PIA00324-PCF-LXTT-IPF.jpgVolcanic Plains and Paterae on Io: Galai Patera (Absolute Natural Colors; credits for the additional process. and color.: Dr Paolo C. Fienga/Lunar Explorer Italia/Italian Planetary Foundation)104 visiteIo's Volcanic Plains and at least 9 (nine) Paterae are shown, once again, in this really beautiful and highly suggestive NASA - Voyager 1 Space Probe image, which spans an area of about 1030 Km (such as approx. 640 miles) from left to right. North is at about the 01:30 o'clock position on the frame. A number of active Volcanic Calderae and huge Lava Flows are visible here: the most important (both for size and activity) is the dark red "teardrop-shaped" Surface Feature visible near the center of the frame, slightly to the right, which is Galai Patera, an approx. 100-Km-long (such as about 62 miles) Lava-flooded Caldera (---> Collapsed Vent). As we have already mentioned in yesterday's APOD, the exact composition of Io's Volcanic Plains and Lava Flows has not been determined yet; however, the prevalent yellow, brown, and orange materials may consist, dominantly, of Sulphur, with Surface Frosts made of Sulphur Dioxide and Silicates (such as Basalt), encrusted with Sulphur and Sulphur Dioxide Condensates. The dark red (and, sometime, almost black) spots visible all around the frame, of course including Galai Patera, are hot Sulphur Lava Lakes, which may remain molten for a long time, thanks to the intrusions of molten Silicate Magma that (probably in an almost continuous way) comes up from deep inside Io. Finally, the whitish patches visible at the upper left corner, in the center and on the lower left side of the picture are, most likely, Fresh Deposits of Sulphur Dioxide Frost.
This picture (which is an Original NASA - Voyager 1 Space Proble color image mosaic published on the NASA - Planetary Photojournal with the n. PIA 00324) has been additionally processed and then re-colorized in Absolute Natural Colors (such as the colors that a human eye would actually perceive if someone were onboard the NASA - Voyager 1 Space Probe and then looked outside, towards the limb of the Jovian moon Io), by using an original technique created - and, in time, dramatically improved - by the Lunar Explorer Italia Team. Different colors, as well as different shades of the same color, mean, among others, the existence of different Elements present on the Surface of Io, each having a different Albedo (---> Reflectivity) and Chemical Composition.MareKromium
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Io-Loki_Patera-PIA00320-PCF-LXTT-IPF.jpgVolcanic Plains and Paterae on Io: Loki Patera (Absolute Natural Colors; credits for the additional process. and color.: Dr Paolo C. Fienga/Lunar Explorer Italia/Italian Planetary Foundation)94 visiteA huge area of Io's Volcanic Plains is well shown in this mosaic of pictures taken by the NASA - Voyager 1 Space Probe. Numerous Volcanic Calderas and Lava Flows are visible here, including the Loki Patera (an active Lava Lake), which is the large shield-shaped and dark red Surface Feature visible in the lower right portion of the mosaic. As a matter of fact, the (sometime) intense light emitted from the Lava that boils inside Loki Patera can even be seen through telescopes, all the way from Earth, and these observations tell us that Loki has been active continuously (or at least every time an astronomer took a good look at it...) since the Voyager 1 Fly-By, which occurred in the month of March of the AD 1979.
The composition of Io's Volcanic Plains and Lava Flows has not been completely determined yet but, in the light of the information that we already possess (and, in particular, once we duly consider the orange-yellow color that can be seen over most of the Surface of Io), it is reasonable to say that they could dominantly consist of Sulphur, with Surface Frosts made of Sulphur Dioxide, Silicates (such as Basalts) encrusted with Sulphur and Sulphur Dioxide Condensates. The bright whitish patches, on the other hand, could probably consist of freshly deposited Sulphur Dioxide Frost. The dark red (and, sometime, almost black) spots, including Loki, are hot Sulphur Lava Lakes, which may remain molten even for a long time, thanks to the intrusions of molten Silicate Magma that (probably in an almost continuous way) comes up from deep inside Io. However, the very ultimate source of heat that keeps Io active, must be the Tidal (Frictional) Heating, due to the perpetual flexure of Io that is caused by the powerful Gravitational Influence of both Jupiter and Europa.
This picture (which is an Original NASA - Voyager 1 Space Proble color image mosaic published on the NASA - Planetary Photojournal with the n. PIA 00320) has been additionally processed and then re-colorized in Absolute Natural Colors (such as the colors that a human eye would actually perceive if someone were onboard the NASA - Voyager 1 Space Probe and then looked outside, towards the limb of the Jovian moon Io), by using an original technique created - and, in time, dramatically improved - by the Lunar Explorer Italia Team. Different colors, as well as different shades of the same color, mean, among others, the existence of different Elements present on the Surface of Io, each having a different Albedo (---> Reflectivity) and Chemical Composition.MareKromium
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