Exploratour - Does Europa have an Ocean?
So, these studies suggest there might be two possibilities with regard to these observations. The first is that an ocean exists and explains all the features we have examined. The crust and lithosphere of Europa would exist over the ocean. Possibilities for the mantle of Europa are shown in this picture. If the crust and lithosphere are not too thick, light from the sun will likely shine through this layer into the ocean beneath. On Earth, we know that there are life forms which can exist under conditions such as these.
The second possiblity is that there is no ocean and these observations are the result of the presence of processes in warm soft ice wherein, if there is melting to make water, the melting takes place only in small areas.
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