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Enceladus-Model3-PIA07727.jpg"Warm" Ice on Enceladus (Model 3)57 visiteOriginal NASA caption:"This graphic represents a possible third model for mechanisms that could generate the water vapor and tiny ice particles detected by Cassini over the Southern Polar terrain on Enceladus.
This model shows sublimation of an "ammonia-water slush" (slush----> fanghiglia costituita da un mix di ammoniaca ed acqua) or "slurry" (slurry---->sin. di slush, ma anche 'combinazione') on the surface".
(9 voti)
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Mimas-PIA07573.jpgMimas in the shadows of the B-Ring58 visiteAs the closest-orbiting of Saturn's intermediate-sized moons, Mimas is occasionally captured against the planet's dim and shadowed northern latitudes. The Moon is seen here next to the shadows cast by the dense B-Ring. The image was taken with the Cassini spacecraft narrow-angle camera on July 18, 2005, at a distance of approx. 1,6 MKM (such as about 1 MMs) from Mimas and at a Sun-Mimas-spacecraft, or phase, angle of 90°. Image scale is 10 Km (about 6 miles) per pixel.
(9 voti)
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Rhea-PIA07572.jpgRhea, from about 342.000 Km57 visiteCassini looks upward at the South Polar Region on Rhea during a recent distant encounter. Rhea's icy surface is so heavily saturated with impact craters that the moon's limb, or edge, has a rugged, bumpy appearance. The bright splotch seen here near the upper right is impact material (or ejecta) from a relatively fresh crater.
The image was taken with the Cassini spacecraft narrow-angle camera on July 14, 2005, at a distance of approx. 342.000 Km (about 212.000 miles) from Rhea and at a Sun-Rhea-spacecraft, or phase, angle of 36°. The image was obtained using a filter sensitive to wavelengths of infrared light centered at 298 nnmts. The image scale is 1,6 Km per pixel
(9 voti)
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NGC-3372.jpgNGC 3372 - The "Carina Nebula"98 visite"...Now I can tell, I know
I was too blind,
I feel the Tiger's smile
Right on my back…
There were no stars to see
Nothing to find,
While I was looking for
Her streaked neck ...
My Fate is done and now
I will to pay…
I guess She's going to jump
She draws Her sword:
My Fate is done,
There's nothing more to say,
She's proud to show me now
The Tigers' World ..."
P.C. Floegers - "Tigers' World"
(9 voti)
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Amalthea-PIA07248_modest.jpgAmalthea: just an "Ice Cube"!66 visiteThese images of Jupiter's moon Amalthea were taken with NASA's Galileo and Voyager spacecraft. Recent findings show that Amalthea is almost pure water ice, hinting that it may not have formed where it now orbits! This information challenges long-held theories about how moons form around giant planets. The image on the left shows the Escape Velocities (EV) color-coded on a shape model of Amalthea with the same viewpoint as the Voyager spacecraft image in the middle panel. Blue represents the lowest EV, barely 1 mt/second (about 3 feet) near the anti-Jupiter end, while red (barely visible) shows the region of much higher EV, nearly 90 mt/second (295 feet). The low EV result from the low density of Amalthea and from its rapid rotation as it orbits Jupiter.
The middle image is a composite from both Galileo and NASA's Voyager spacecraft and shows Amalthea from the anti-Jupiter side. The visible area is about 150 Km (about 93 miles) across.
The Sun is behind the spacecraft, resulting in loss of visible shadows. The brighter markings on the ends of a ridge are prominent in this view.
On the right is a Galileo image of Amalthea, (see PIA02532), with the bright spots on the end of Amalthea seen from the leading side of the satellite. Here the Sun is to the left and topography, such as the impact crater at the right, is visible.
Amalthea is Jupiter's fifth largest moon. It orbits about 181,000 kilometers (112,468 miles) from Jupiter, considerably closer than the Moon orbits Earth. It measures about 168 miles in length and half that in width. Galileo passed within about 99 miles of the moon on Nov. 5, 2002. After more than 30 close encounters with Jupiter's four largest moons, the Amalthea flyby was the last moon flyby for Galileo. The mission began orbiting the planet in 1995.
(9 voti)
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Colliding Galaxies.jpgColliding Galaxies81 visite"...Ditemi se questo non è un Sistema perfetto: i Servi, mentre a parole rigettano e condannano a morte i loro padroni, nei fatti diventano i loro Tutori, i loro più fedeli Protettori.
I loro amanti perversi.
E dunque così sia: il pastore ha lasciato le pecore libere ed i cani, anch'essi sciolti, possono cercare il loro Destino nel Mondo, senza più guinzagli e museruole eppure...Eppure i cani, correndo, sbavando ed abbaiando ferocemente alla loro Libertà, si affannano ad inseguire le pecore ed a riunirle, per poterle riportare, prima dell'imbrunire, al loro padrone.
E' forse questa un'Azione Riflessa?!?...".
P.C. Floegers - "In the Paradox"
(9 voti)
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Mimas-PIA06257.jpgMimas: surface geology through "false colors"57 visiteThe image at the left is a narrow angle clear-filter image, which was separately processed to enhance the contrast in brightness and sharpness of visible features. The image at the right is a color composite of narrow-angle ultraviolet, green, infrared and clear filter images, which have been specially processed to accentuate subtle changes in the spectral properties of Mimas' surface materials. To create this view, 3 color images (ultraviolet, green and infrared) were combined into a single black and white picture that isolates and maps regional color differences. This "color map" was then superimposed over the clear-filter image at the left.
The combination of color map and brightness image shows how the color differences across the Mimas surface materials are tied to geological features.
Shades of blue and violet in the image at the right are used to identify surface materials that are bluer in color and have a weaker infrared brightness than the average Mimas materials (green).
(9 voti)
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Saturn-PIA06436.jpgSaturn's Aurora60 visiteThe Cassini spacecraft has obtained new images of Saturn's auroral emissions, which are similar to Earth's Northern Lights. Images taken on June 21, 2005, with Cassini's UVA Imaging Spectrograph are the first from the mission to capture the entire "oval" of the auroral emissions at Saturn's South Pole.
In the side-by-side, false-color images, blue represents aurora emissions from H gas excited by electron bombardment, while red-orange represents reflected sunlight. The images show that the aurora lights at the Polar Regions respond rapidly to changes in the Solar Wind. Previous images have been taken closer to the Equator, making it difficult to see the Polar Regions. Changes in the emissions inside the Saturn South-Pole aurora are visible by comparing the 2 images, taken about 1 hour apart. The brightest spot in the left aurora fades and a bright spot appears in the middle of the aurora in the second image. Like Earth's aurora, those on Saturn form in an oval at high latitudes around each pole, along with associated spots and streaks. The ultraviolet imaging spectrograph data shows that the Saturn aurora lasts at least one hour, but small changes are visible in that time between the two images.
The same process produces auroras on both planets: variations in the plasma environment release trapped electrons, which stream along the magnetic field lines into the upper atmosphere. There, they collide with atoms and molecules, exciting them to higher energies. The atoms and molecules release this added energy by radiating light at particular characteristic colors and wavelengths. On Earth, this light is mostly from oxygen atoms and nitrogen molecules. On Saturn, it is from emissions of molecular and atomic hydrogen.
(9 voti)
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NGC-1275.jpgNGC 1275 - Unusual Gas Filaments87 visite"...Incertum est quo loco te Mors expectet, itaque tu illam omni loco expecta..."
(Seneca)
"...tu non sai in quale luogo la Morte ti aspetta, perciò attendila ovunque..."
(9 voti)
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M-042-1.jpgThe 'Ghosts' deep inside M 4261 visite"...In quale istante il continuo accumulo di informazioni ed esperienze diventa ciò che chiamiamo "consapevolezza"?..."
dal film "I, Robot"
(9 voti)
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SaturnandCompanions-PIA07538.jpgSaturn's Space Panorama63 visiteCaption NASA originale:"Three of Saturn's icy moons are seen here, along with the magnificent water-ice rings and the cold gaseous envelope of the Planet's atmosphere. Saturn's dark shadow stretches completely across the rings.
At nine and a half times farther from the Sun than Earth, Saturn inhabits the deep cold of the outer Solar System. The Sun appears only 1% as bright there as it appears at Earth, creating an environment where ice dominates over rock.
The icy Moons visible here, from left to right are: Janus (181 kilometers, or 113 miles, across), Enceladus (505 kilometers, or 314 miles, across), and Epimetheus (116 kilometers, or 72 miles, across).
The image was taken in visible green light with the Cassini spacecraft wide-angle camera on June 1, 2005, at a distance of approximately 2,4 MKM from Saturn. The image scale is 139 Km per pixel".
(9 voti)
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Utopia_Planitia-Smoke-B-M0202863-PCF-LXTT.jpgControversial Surface Feature in Utopia Planitia (EDM n.1)74 visitevedi il commento al frame che precede
(9 voti)
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