| Semi-recent simulations of impacts on Europa's surface are
indicative that the rock-solid ice shell must be at minimum 3-4 kilometres
thick (otherwise there should be no central peak crater, contradicting the fact that
we do see them), with no calculated upper bound in sight.
Another analysis, this time of large plateaus on Europa, proclaims a minimum 6 kilometres of ice.
One model to explain the big pits and domes on the surface is that convection currents
in the liquid water cause very slow convection currents in the solid water. This would
require at least 20 kilometres of ice.
Considering
that there are about 100 kilometres of water (solid or liquid) above the rocky core, how much in-between really is
made up of ice? How thick could it be while still allowing life to survive?
Does Europa have all the other characteristics that one would need to get life? | 
