| Piú votate - Saturn: the "Ringed Beauty" and His Moons |
Rhea from approx. 8.336.000 Km.jpgRhea from approx. 8.336.000 Km53 visitenessun commento
(4 voti)
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Hyperion-PIA08240.jpgPink Hyperion...72 visiteCaption NASA originale:"Unlike most of the dull grey moons in the Solar System, Hyperion's color is a rosy tan (---> Light Pink), as this view shows.
The origin of the moon's unusual hue is not known. Some scientists suspect the color comes from falling debris from moons further out.
A similar origin has been suggested for the dark reddish material on Saturn's moon Iapetus.
Images taken using red, green and blue spectral filters were combined to create this natural color view. The images were taken in visible light with the Cassini spacecraft narrow-angle camera on June 28, 2006 at a distance of approx. 291.000 Km (about 181.000 miles) from Hyperion. Image scale is roughly 2 Km (a little more than 1 mile) per pixel".
(7 voti)
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Saturn-N00047654.jpgWhite ice-clouds on Saturn's upper atmosphere (2)54 visiteOriginal caption:"N00047654.jpg was taken on January 02, 2006 and received on Earth January 03, 2006. The camera was pointing toward Saturn that, at the time, was approximately 2.732.434 Km away, and the image was taken using the CL1 and CL2 filters. This image has not been validated or calibrated".
Note: anche questa seconda immagine (molto suggestiva) ci mostra che, negli strati superiori dell'atmosfera di Saturno, sembra esserci spazio per il passaggio di nuvole bianche - presumibilmente formate da ghiaccio d'acqua - le quali, nelle loro caratteristiche esteriori, ci ricordano i cirri ed i cirro-strati che, di tanto in tanto, vediamo anche nei nostri cieli.
Se, al di sotto di queste nuvole, piova o nevichi, non ci è dato saperlo ma, a quanto sembra, questa possibilità - già verificata per le nuvole di Giove - è tutt'altro che remota.
(7 voti)
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Rhea-PIA06641.jpgTirawa impact basin on Rhea54 visiteCaption NASA originale:"The large Tirawa impact basin on Saturn's moon Rhea is visible at the two o'clock position in this Cassini image. This view shows principally the trailing hemisphere on Rhea and is centered on the moon's equator. North is up and tilted 25° to the left.
The image was taken with the Cassini spacecraft narrow-angle camera on March 13, 2005, through a filter sensitive to wavelengths of ultraviolet light centered at 338 nnmts.
The image was obtained at a distance of approximately 1,7 MKM(such as 1,1 MMs) from Rhea and at a phase angle of 90°. Resolution in the original image was 10 Km (approx. 6 miles) per pixel. The image has been contrast-enhanced and magnified by a factor of two to aid visibility".
(7 voti)
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Japetus-temp.1-PIA07006_modest.jpgJapetus Temperature Variation Map55 visiteCaption NASA originale:"This plot shows how daytime temp.s at low latitudes on the Dark Material on Japetus vary with time of day from about 130 Kelvin (-226 F) at noon to about 70 Kelvin (-334 F) at sunset. The observations are compared to a "forecast" model (green line) which predicts temperatures based on an assumed value of a parameter called the "thermal inertia. Rock or solid ice has a high thermal inertia (approx. 2.000.000 as measured in the obscure units used for thermal inertia), meaning that it is good at storing heat and cools down or heats up relatively slowly. On Japetus, in contrast, temperatures drop precipitously in the afternoon as the Sun sinks towards the horizon and a very small value of the thermal inertia (30.000 units) is needed in the model to match the data. This means that Japetus's surface is extremely bad at storing heat and is thus extremely fluffy, probably due to the pulverizing effect of billions of years of meteorite impacts (...)".
(7 voti)
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Saturn-N00021000.jpgSaturn and his Rings53 visitenessun commento
(7 voti)
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AI-Saturn-Streak in the Sky-N00018041.jpgA new "Bright Streak" in the Sky of Saturn85 visiteUna nuova "striscia luminosa" (bright streak) nel Cielo di Saturno, ripresa il giorno 14 Settembre 2004. Che dire? Secondo noi - anche se accettassimo acriticamente la teoria che spiega alcune (comunque brevi e piuttosto deboli) striature di luce che, spesso, appaiono nelle immagini scattate guardando verso lo spazio come "raggi cosmici" - questa specifica "striscia" sembra qualcosa di molto particolare. Qualcosa che non può essere semplicemente ricondotto all'emissione luminosa di una micro-particella che schizza nello spazio a velocità relativistica.
Secondo noi, questa striscia (come anche altre, riprese dalla superficie di Marte) è causata da qualcosa di diverso.
Cosa?
E se lo sapessimo...
(7 voti)
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The Rings from approx. 30.000 Km.jpgThe Rings from app.x 30.000 Km54 visitenessun commento
(7 voti)
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PIA05406-Clouds.jpgSaturn's swirls and clouds from approx. 22.000.000 Km54 visitenessun commento
(7 voti)
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Hyperion-N00040280.jpgHyperion (8)54 visiteLa distanza si accorcia, anche se non di molto: siamo a circa 31.000 Km da Hyperion. Non molto da dire per quanto attiene questo frame il quale è molto simile al precedente.
(10 voti)
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Hyperion-N00040201.jpgHyperion (3)54 visiteQuali altri processi possano aver condotto ad un simile risultato, però, è ancora un mistero e noi non pensiamo che sarà uno scherzo giungere alla Verità (con tutto il rispetto per le interessanti Teorie del Gruppo che si chiama "Thunderbolts")...
In questo frame, siamo a poco più di 100.000 Km da Hyperion.
(10 voti)
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Mimas-PIA07639.jpgThe "Eye" of Mimas: Herschel Crater in the Sun-light55 visiteImpact-battered Mimas steps in front of Saturn's Rings, showing off its giant 130-Km (about 80-mile) wide Herschel Crater.
The illuminated terrain seen here is on the moon's Leading Hemisphere. North on Mimas is up and rotated 20° to the left.
The image was taken in visible green light with the Cassini narrow-angle camera on Oct. 13, 2005 at a distance of approx. 711.000 Km (roughly 442.000 miles) from Mimas and at a phase angle of 112°.
The image approx. scale is 4 Km (about 3 miles) per pixel.
(15 voti)
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