| Piú votate - Jupiter: the "King" and His Moons |
Europa-fullcolor-PIA02590_modest.jpgEuropa in full colors65 visitenessun commento
(8 voti)
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Jupiter-PIA02865-4.jpgA "deep look" in the "deep clouds" of Jupiter58 visiteFinally, this is the combination of the 3 images taken from Cassini using the 3 different filters.
This picture reveals cloud structures and movements at different depths in the atmosphere around Jupiter's South Pole. Cassini's cameras come equipped with filters that sample 3 wavelengths where Methane gas absorbs light. These are in the RED (619 nnmts) and in the NEAR-INFRARED (at 727 and 890 nnmts). Absorption in the 619 nnmts filter is weak. It is stronger in the 727 nnmts band and very strong in the 890 nnmts band where 90% of the light is absorbed by Methane gas.
Light in the weakest band can penetrate the deepest into Jupiter's atmosphere. It is sensitive to the amount of cloud and haze down to the pressure of the water cloud (which lies at a depth where pressure is about 6 times the atmospheric pressure at sea level on the Earth).
Light in the strongest methane band is absorbed at high altitude and is sensitive only to Ammonia cloud level and higher (with pressures less than about one-half of Earth's atmospheric pressure) and the middle methane band is sensitive to the ammonia and ammonium hydrosulfide cloud layers as deep as two times Earth's atmospheric pressure.
(7 voti)
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Europa-crescent-V2-PIA00325.jpgCrescent Europa from Voyager 257 visiteThis mosaic of Europa, the smallest Galilean satellite, was taken by Voyager 2. This face of Europa is centered at about the 300° meridian. The bright areas are probably ice deposits, whereas the darkened areas may be the rocky surface or areas with a more patchy distribution of ice. The most unusual features are the systems of long linear structures that cross the surface in various directions. Some of these linear structures are over 1000 Km long and about 2 or 3 Km wide. They may be fractures or faults which have disrupted the surface.
(7 voti)
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IO 4.jpgIo (Flying over a volcanic eruption and a sea of sulphur - Tvashtar Catena)104 visiteAn active volcanic eruption on Jupiter's moon Io was captured in this image taken on February 22, 2000 by NASA's Galileo spacecraft. Tvashtar Catena, a chain of giant volcanic calderas centered at 60 degrees north, 120 degrees west, was the location of an energetic eruption caught in action in November 1999. A dark, "L"-shaped lava flow to the left of the center in this more recent image marks the location of the November eruption. White and orange areas on the left side of the picture show newly erupted hot lava, seen in this false color image because of infrared emission. The two small bright spots are sites where molten rock is exposed to the surface at the toes of lava flows. The larger orange and yellow ribbon is a cooling lava flow that is more than more than 60 kilometers (37 miles) long. Dark, diffuse deposits surrounding the active lava flows were not there during the November 1999 flyby of Io.
This color mosaic was created by combining images taken in the near-infrared, clear, and violet filters from Galileo's camera. The range of wavelengths is slightly more than that of the human eye. The mosaic has been processed to enhance subtle color variations. The bright orange, yellow, and white areas at the left of the mosaic use images in two more infrared filters to show temperature variations, orange being the coolest and white the hottest material. This picture is about 250 kilometers (about 155 miles) across. North is toward the top and illumination from the Sun is from the west (left).
(14 voti)
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Io-flares and eruptions-PIA02254.jpgFlares and Eruptions on the limb of crescent Io100 visiteUn frame da ricordare, per bellezza ed importanza: ecco come appaiono le "flares" sul bordo di un pianeta in ombra. Sappiamo, in questo caso, che si tratta di eruzioni ed outgassing in corso e nessuno ne dubita. Tuttavia, quando fenomeni similari (o identici) vengono osservati sulla Luna, tutti (o quasi) gli Scienziati ed i Ricercatori si affrettano a dire che non è possibile e che deve trattarsi di sviste o bagliori da impatto. Ma perchè fa così paura l'idea che la Luna possa essere ancora in parte "viva"?
Voyager 2 took this picture of Io July 10, 1979, from a range of 1.2 million kilometers (750,000 miles). It was one of the last of an extensive sequence of "volcano watch" pictures planned as a time lapse study of the nearest of Jupiter's Galilean satellites. The sunlit crescent of Io is seen at the left, and the night side illuminated by light reflected from Jupiter can also be seen. Three volcanic eruption plumes are visible on the limb. All three were previously seen by Voyager 1. On the bright limb Plume 5 (upper) and Plume 6 (lower) are about 100 kilometers high, while Plume 2 on the dark limb is about 185 kilometers high and 325 kilometers wide. The dimensions of Plume 2 are about 1 1/2 times greater than during the Voyager 1 encounter, indicating that the intensity of the eruptions has increased during the four-month time interval between the Voyager encounters. The three volcanic eruptions and at least three others have apparently been active at roughly the same intensity or greater for a period of at least four months.
(15 voti)
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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)155 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
(5 voti)
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Ganymede-V1-PIA02278_modest.jpgThe limb of Ganymede (from Voyager 1)54 visiteThis picture of Ganymede, Jupiter's largest satellite, was taken by Voyager 1 on the afternoon of March 5, 1979 from a range of 253.000 Km (about 151.800 miles). The picture is centered at 66° South Latitude and 3° Longitude and shows the south western limb region of Ganymede. The smallest features visible are about 2,5 Km (roughly 1,5 miles) across. The surface shows numerous impact craters, many of which have extensive bright ray systems. Light bands traversing the surface contain alternating bright and dark lines which probably represent deformation of the icy central material.
(12 voti)
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Jupiter_s System-PIA01481.jpgJupiter's (Main) System66 visiteCaption NASA originale:"Jupiter and its four planet-size moons, called the Galilean Satellites, were photographed in early March by Voyager 1 and assembled into this collage. They are not to scale but are in their relative positions. (...) Nine other much smaller satellites circle Jupiter, one inside Io's orbit and the other millions of miles from the Planet.
Not visible is Jupiter's faint ring of particles, seen for the first time by Voyager 1".
(8 voti)
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Callisto-full disk-PIA03456_modest.jpgCallisto from Galileo92 visiteCaption NASA originale:"Bright scars on a darker surface testify to a long history of impacts on Jupiter's moon Callisto in this image of Callisto from NASA's Galileo spacecraft.
The picture, taken in May 2001, is the only complete global color image of Callisto obtained by Galileo, which has been orbiting Jupiter since December 1995. Of Jupiter's four largest moons, Callisto orbits farthest from the giant planet.
Callisto's surface is uniformly cratered but is not uniform in color or brightness. Scientists believe the brighter areas are mainly ice and the darker areas are highly eroded, ice-poor material".
(8 voti)
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Jupiter-Red_Spot-BJ.jpgJupiter's Great Red Spot from Voyager 1 (Credit: NASA, JPL; Digital processing: Dr Björn Jónsson - IAAA)113 visiteCaption NASA:"It is a hurricane twice the size of the Earth. It has been raging at least as long as telescopes could see it, and shows no signs of slowing. It is Jupiter's Great Red Spot, the largest swirling storm system in the Solar System.
Like most astronomical phenomena, the Great Red Spot was neither predicted nor immediately understood after its discovery. Still today, details of how and why the Great Red Spot changes its shape, size, and color remain mysterious. A better understanding of the weather on Jupiter may help contribute to the better understanding of weather here on Earth.
The above image is a recently completed digital enhancement of an image of Jupiter taken in 1979 by the Voyager 1 Spacecraft as it zoomed by the Solar System's largest planet.
At about 117 AU from Earth, Voyager 1 is currently the most distant human made object in the Universe and expected to leave the entire Solar Heliosheath any time now".MareKromium
(4 voti)
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Io-PIA01071.jpgAs Time Goes By...On Io! (2)55 visitenessun commento
(15 voti)
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Ganymede-PIA00716.jpgGanymede (full disk) from about 3,4 MKM55 visiteThis color picture of Ganymede, Jupiter's largest satellite, was taken on the afternoon of March 2, 1979, by Voyager 1 from a distance of about 3,4 MKM (about 2,1 MMs). This photograph was assembled from 3 black-and-white pictures in the Image Processing Laboratory at JPL. (...)
Ganymede is slightly larger than the planet Mercury but has a density almost three times less than Mercury. Therefore, Ganymede probably consists in large part of ice. At this resolution the surface shows light and dark markings interspersed with bright spots. The large darkish area near the center of the satellite is crossed by irregular light streaks somewhat similar to rays seen on the Moon. The bright patch in the southern hemisphere is reminiscent of some of the larger rayed craters on the Moon caused by meteorite impact.
(14 voti)
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