Just to elaborate a bit on artfuldodger's node, the node title is from 2010, by Arthur C. Clarke. In 2010, it is found that there is an overarching consciousness overlooking life. Because there is the potential for Europa to develop its own indigenous life, especially if Jupiter were to become a small star, humankind is told to stay away from it by this consciousness. Of course, humankind doesn't pay much attention of course, despite the fact that humanity is given the rest of the satellites of Jupiter to play with.