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.

2000 April 27
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Calderas And Cliffs Near Io's South Pole
Credit: PIRL (Univ. of Arizona), Galileo Project, NASA

Explicatie: (Edit) Braving intense radiation belts, the Galileo spacecraft once again flew past the surface of Jupiter's moon Io (sounds like EYE-oh) on February 22. Combining high resolution black and white images from that flyby with color data recorded last summer has resulted in this dramatic view of a region near the volcanic moon's south pole. An active and alien landscape, the bright white areas are likely due to sulfur dioxide frost and seem to be concentrated near ridges and cliffs. The three ominous black spots, each about 6-12 miles across, are volcanic craters or calderas covered with recent dark lava. A sinuous channel connects the lower left caldera with a yellowish lava flow. Io is small, but its continuous activity is driven by the drastic tides induced by Jupiter and the other Jovian moons. It is estimated that the resulting volcanism completely resurfaces Io every million years.

Imaginea de maine: Leonid Glowworm

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