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The nucleus of Comet 67P / Churiumov-Gerasimenko not like maybe expected a dirty snowball, but that does not mean that snow, or rather ice at all there. European Space Agency scientists have just published photos showing where the ice beneath layers of rubble and dust sticking out. Images recorded with the help of high resolution cameras Rosetta published in the latest issue of the journal “Astronomy & amp; Astrophysics.”
Observations evolution of comets approaching the Sun indicated that a substantial portion must be composed of ice, which under the influence of solar radiation growing sublimates. Gas and dust escapes into space after creating a picturesque fringe, finally braids. As it turns out, some dust remains near the comet’s nucleus and as far as his activity during the distance from the sun decreases, begins to fall. This is because the surface of a comet nucleus 67P / Churiumov-Gerasimenko just like any other – observed during previous missions – is dark and ice on it almost not visible.
Studies have shown early Rosetta probe around the nucleus of the presence of gases such as steam Water, carbon dioxide and carbon monoxide. One could expect that they escape from frozen beneath the surface. Now in pictures taken as early as September last year, the OSIRIS camera failed to identify about 120 districts whose brightness is up to 10 times greater than the average brightness of the entire surface. This is probably the place where you can see bare ice.
Pictures were taken from a height of about 30-40 kilometers from the center of the nucleus. Color images are an outcome of three monochrome images made at different times in the red wavelength range (882.1nm), green (649.2nm) or blue (360.0nm).
Some communities bright solids can be seen at the foot of the cliffs, which means that there has been there for processes erosion or collapse of parts of the walls and it revealed ice. But there are places where bright points have no relationship with the surrounding terrain. Scientists do not exclude that these rocks could be transferred in those places during previous phases of high activity of the comet.
The presence of water ice is the most likely explanation for the observed images – says the first author of the paper, Antoine Pommerol the University of Bern. At the time of our observations, the comet was still far enough away from the Sun that influenced his radiant plain ice would sublimate no faster than a millimeter per hour, if it were solid carbon or carbon monoxide, in these conditions already zdążyłby disappear – he added.
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