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SPACE-MERCURY-MESSENGER
In this NASA photo obtained April 2, 2013, the MESSENGER spacecraft imaged a plume of material erupting from the surface of the innermost planet. In an MDIS image taken early April 1, 2013, a bright source of light may be seen above Mercury's southern hemisphere. Located at approximately 67°S, 55°E, close to the newly named Alver basin, this light source appears to be MESSENGER team members are currently analyzing images of the eruption. One hypothesis under consideration is that the brightness indicates the presence of a "fire fountain," an eruption during which lava is ejected from depth in a jet-like spray of molten rock. There also appears to be a dimmer cloud of material above the central plume. Under the fire fountain hypothesis, this higher cloud may be composed of smaller droplets of lava of a size that allows them to be blasted to greater altitudes. Most of these droplets will probably fall back to the surface, producing a distinctive "pyroclastic halo" around the vent like those seen elsewhere on Mercury. An alternative possibility is that the plume is a "geyser" of volatile materials, analogous to the plume at Saturn's moon Enceladus. Under this scenario, a pocket of volatile-rich material may have been heated by the intrusion of subsurface magma, solar tidal dissipation, or some other process, fueling a geyser-like eruption at the surface.= RESTRICTED TO EDITORIAL USE - MANDATORY CREDIT " AFP PHOTO / NASA/ Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington /" - NO MARKETING NO ADVERTISING CAMPAIGNS - DISTRIBUTED AS A SERVICE TO CLIENTS =
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Detalii fotografie |
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-, SPACE |
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AFP / Mediafax Foto |
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HO |
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2 Aprilie 2013 |
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2048 x 2048 (436.66 KB) |
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