According to the evaluation of data, there may be water – and life – on Ganymede as well as on Jupiter’s moons Callisto and Europa
Maybe there is flowing water on the moon of Jupiter Ganymede. At least the existence of liquid salt water under the ice crust could be explained by the magnetic data recorded by Nasa’s Galileo spacecraft during its flyby in May 2000. Of course there is now again talk about the possibility of extraterrestrial life.
"This view of Nicholson Regio and Arbela Sulcus on Jupiter’s moon Ganymede shows the marked contrast between the smooth, lighter band (Arbela Sulcus) and the surrounding, tectonically deformed dark terrain. This observation was carried out, among other things, to decide between different theoretical models proposing either a tectonic or a volcanic cause for the formation of Arbela Sulcus (and also other, geologically similar areas on Ganymede). The volcanic model ames that a relatively pure, water-rich "Lava" filled an originally tectonically formed hollow and subsequently cooled down, forming a relatively smooth surface. Tectonic models suggest that the older, darker terrain was subjected to faulting and deformation processes, destroying the pre-existing surface forms and allowing deeper pure ice to rise to the top. However, the analysis of the photos suggests a third, unexpected possibility: Arbela Sulcus, similar to the bands on Europe, could have been formed by a tectonic division of the crust and reswelling material from below." German Aerospace Center
At a meeting of the American Geophysical Society in San Francisco on Saturday, scientists said that after analyzing the data, not only on the Jupiter moons Callisto and Europa (Auberirdische microorganisms on "Europe"?), but could also be on Ganymede river water. However, the water – or another conductive substance – was located at a depth of 200 kilometers below the surface. Moreover, data from the infrared spectrometer showed that the minerals visible in some places on the surface had once been covered by salt water.
Ganymede is the coarse moon of Jupiter and of our solar system, it is even coarser than the planets Mercury and Pluto. However, the indications of water are more difficult to interpret than for Europa and Callisto, said Margaet Kivelson of the University of California. Ganymede itself has a strong magnetic field, not only a secondary one caused by Jupiter like the other moons. Nevertheless, the magnetic field on Ganymede suggests that there is something beneath the surface that is more conductive than ice, according to Kivelson. If the layer is 200 kilometers below the surface, as amed, then it could be liquid water, if it is as salty as the seas of the Earth. The radioactivity measured in the interior of the moon could be sufficient for the water, probably trapped between two thick layers of ice, to remain fluid due to the warmth. "I would be surprised if there was no ocean on Ganymede", says Dave Stevenson of Caltech. "But the question, whether there is it there, is different from the question, whether one can read that clearly from the numbers." Where there is water, there could also be life.
Am 28.12. Galileo will once again fly close to Ganymede. Since December 1995 the probe orbits Jupiter. And on 30. December the probe Huygens/Cassini meets Galileo at Jupiter (Historical encounter at Jupiter).