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as16-114-18439.jpgAS 16-114-18439 - The "UV" Astronomy Camera57 visiteCaption NASA:"Interesting cross-Sun from the south of the UV Astronomy Camera, showing Charlie Duke in the background with the Rover and the Flag to the left".
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Psp_001691_1320_red.jpgGullied Trough in Noachis Terra(False Colors)57 visitePSP_001691_1320 shows gullies in a semi-circular trough in Noachis Terra. The gullies are observed to face all directions.
It is interesting to note that the gully morphology seen here depends on the orientation of the gullies. The morphology differences are most pronounced on the sunlit slope, with the gullies facing South (Dx) being more deeply incised than those facing the West. It is unknown what caused the different gully morphologies, but there are several possibilities.
Gullies are proposed to form at locations determined by the availability of a forming liquid (thought to be water) and/or the amount of insolation the slope receives, among other factors. It is possible that the deeper gullies experienced more erosional events or that their erosional events were more effective for undetermined reasons. It is also possible that the gullies formed at different times such that they did not have the same amount of water — either for an individual flow or total — available to them.
Also, the underlying topography could make the gullies appear relatively more incised without this actually being the case.
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Psp_001691_1320_red~0.jpgGullied Trough in Noachis Terra (extra-detail mgnf - false colors)57 visiteThe majority of the gullies on both sides of the trough appear to originate at a boulder-rich layer seen in this subimage.
The layer appears dark on the sunlit slope because the boulders sticking out from the slopes cast shadows. If these gullies formed by water from the subsurface, then it is possible that this layer is a permeable layer that conducted water to the surface.
The layer is deteriorating and traveling down slope in the form of boulders.
These boulders can clearly be seen in the alcoves of the gullies on both sides of the trough.
Note that the alternating stripes on the lower right (Dx) side of the image are an artifact from camera noise. They are not real features.
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Rhea-PIA08886.jpgDrawing Out Details on Rhea57 visiteRhea displays a marked color contrast from North to South that is particularly easy to see in the extreme color-enhanced Cassini spacecraft view presented here.
A clear filter image is also presented (left) alongside the color composite (right).
To create the false-color view, ultraviolet, green and infrared images were combined into a single picture that isolates and maps regional color differences.
This "color map" was then superimposed over a clear-filter image that preserves the relative brightness across the body.
The combination of color map and brightness image shows how colors vary across the surface of Rhea. The origin of the color differences is not yet understood, but may be caused by subtle differences in the surface composition or the sizes of grains making up the icy surface material.
This view looks toward the Trailing Hemisphere on Rhea. The view shows southerly latitudes on Rhea, down to the South Pole. North is up and rotated 17° to the right.
The image was taken in visible light with the Cassini spacecraft narrow-angle camera on Jan. 17, 2007 at a distance of approx. 457.000 Km (about 284.000 miles) from Rhea.
Image scale is roughly 3 Km (a little less than 2 miles) per pixel.
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Io-022707_Erupt_on_Io.jpgRestless Tvashtar57 visiteThe first images returned to Earth by New Horizons during its close encounter with Jupiter feature the Galilean moon Io, snapped with the Long Range Reconnaissance Imager (LORRI) at 0840 UTC on February 26, while the moon was 2,5 MMs (about 4 MKM) from the spacecraft.
Io is intensely heated by its tidal interaction with Jupiter and is thus extremely volcanically active. That activity is evident in these images, which reveal an enormous dust plume, more than 150 miles high, erupting from the volcano Tvashtar. The plume appears as an umbrella-shaped feature of the edge of Io's disk in the 11 o'clock position in the right image, which is a long-exposure (20-millisecond) frame designed specifically to look for plumes like this. The bright spots at 2 o'clock are high mountains catching the setting sun; beyond them the night side of Io can be seen, faintly illuminated by light reflected from Jupiter itself.
The left image is a shorter exposure — 3 milliseconds — designed to look at surface features. In this frame, the Tvashtar volcano shows as a dark spot, also at 11 o'clock, surrounded by a large dark ring, where an area larger than Texas has been covered by fallout from the giant eruption.
This is the clearest view yet of a plume from Tvashtar, one of Io's most active volcanoes. Ground-based telescopes and the Galileo Jupiter orbiter first spotted volcanic heat radiation from Tvashtar in November 1999, and the Cassini spacecraft saw a large plume when it flew past Jupiter in December 2000. The Keck telescope in Hawaii picked up renewed heat radiation from Tvashtar in spring 2006, and just two weeks ago the Hubble Space Telescope saw the Tvashtar plume in ultraviolet images designed to support the New Horizons flyby.
The New Horizons images of the plume — which show features as small as 20 Km (12 miles), are 12 times sharper than the HST images and about three times sharper than the Cassini images. "This is the best image of a large volcanic plume on Io since the Voyager flybys in 1979" says John Spencer, deputy leader of the New Horizons Jupiter Encounter Science Team from Southwest Research Institute.
"If the Tvashtar plume remains active, the images we take later in the encounter should be even better".
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The_Rings-PIA08887.jpgHeading to the Darkness57 visiteCaption NASA:"This strikingly crisp view shows Atlas heading into Saturn's shadow at upper left. The moon's basic, elongated shape is easy to detect here. Above Atlas, a bright clump in the F-Ring also heads toward the darkness. This view looks toward the unlit side of the Rings from about 30° above the Ring-Plane.
The image was taken in visible light with the Cassini spacecraft narrow-angle camera on Jan. 19, 2007 at a distance of approx. 1,2 MKM (about 700.000 miles) from Atlas. Image scale is roughly 7 Km (about 4 miles) per pixel".
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OPP-SOL1102-1M226014927EFF798DP2956M1M1.jpgLook at the "Martian Light-Horse"! (4) - Sol 110257 visitenessun commentoMareKromium
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OPP-SOL1102-1M226014794EFF798DP2936M1M1.jpgLook at the "Martian Light-Horse"! (2) - Sol 110257 visite...Quasi definito...MareKromium
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OPP-SOL1102-1M226014636EFF798DP2956M1M1.jpgLook at the "Martian Light-Horse"! (1) - Sol 110257 visite...Inizia la "formazione" del "Cavallo Marziano"...
Un vero peccato che gli Amici di Pasadena non ci forniscano più dati sull'ora della ripresa ed i filtri usati (per non parlare della distanza fra MI ed oggetto ripreso, nonchè le dimensioni effettive del rilievo ripreso)...MareKromium
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as12-52-7731.jpgAS 12-52-7731 - Lunar Horizon57 visiteView from lunar orbit
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as12-51-7549.jpgAS 12-51-7549 - Approaching the Lunar Terminator57 visitenessun commentoMareKromium
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as12-51-7543.jpgAS 12-51-7543 - Craters and Highlands57 visitenessun commentoMareKromium
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