High relative: The temperatures I suggested were wishful thinking. If both bodies are 274 degrees k at the center and a few other hot spots, then nearly all the below surface water is ice (or chemically combined) and there is no steam and very little water vapor below the surface. Human colonists will have trouble extracting useable amounts of water if it is typically only a few parts per million and frozen solid a few meters below the surface. Native micro organisms and other creatures are less probable in ice.
If the hot spots, are widely scattered how could the center be more than a few degrees cooler than the average of the hot spots? Unless there are geysers, lava or hot springs, internal heat travels toward the surface by conduction and the outer surface is the only place heat can be lost, so typically the surface is cooler at night than below the surface, or am I missing something? Neil
