In the (unlikely?) event that complex intelligent life is discovered under Europa's surface, I find myself musing over how utterly incomprehensible it would be for them to encounter humans.

Our sky is open to the heavens and in spite of this it's really only in the past half millenia (ignoring Aristarchus) that we've had solid observational evidence to demonstrate that the heavenly bodies are physical worlds like our own.

Consider, then, the position of the intelligent squid-beings of Europa. Their intellect is every bit as refined and analytic as ours. Their fourteen appendages give them a dexterity that far surpasses anything that can be achieved by our opposing thumb. However, they are bounded entirely by kilometres of ice. They have no reason even to conceive of the possibility that there might be another side to the limits of their world. For humans to enter their domain would be akin to creatures stepping out of thin air, bringing tales of a universe infinitely larger than their own, surrounding them on all sides. Makes you wonder if we are similarly bounded, and if so, by what.

tl;dr Europa is Flatland.