Imaginea Astronomica a Zilei

Descopera cosmosul! In fiecare zi este prezentata o noua imagine sau fotografie a universului nostru fascinant, insotita de o explicatie scurta din partea unui astronom profesionist.

2005 February 15
See Explanation.  Clicking on the picture will download
 the highest resolution version available.

Saturn's Moon Rhea from Cassini
Credit: Cassini Imaging Team, SSI, JPL, ESA, NASA

Explicatie: (Edit) Each moon of Saturn seems to come with its own mystery. Rhea, Saturn's second largest moon behind Titan, shows unusual wisps, visible above as light colored streaks. Higher resolution images of similar wisps on Dione indicate that they might be made of long braided fractures. Rhea is composed mostly of water ice, but likely has a small rocky core. Rhea's rotation and orbit are locked together, just like Earth's Moon, so that one side always faces Saturn. A consequence of this is that one side always leads the other. Rhea's leading surface is much more heavily cratered than the trailing surface, pictured above. The above image in natural color was taken last month by the Cassini robot spacecraft in orbit around Saturn.

Imaginea de maine: sun morph


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Autori & editori: Robert Nemiroff (MTU) & Jerry Bonnell (USRA)
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NASA Official: Jay Norris. Specific rights apply.
Un serviciu al: LHEA at NASA / GSFC
& Michigan Tech. U.