Re: Europa, Jovian Moon
Someone who knows will answer this properly, but off the top of my head what I've read is that it is frozen for miles and miles down.
And, it would have a covering of debris which would inhibit sublimation. Being without a liquid phase and limited chance for evaporation of one type or another, wouldn't have much choice but to sit there.
What I wonder is how the extent of water on Europa has been known for some time and that of Mars is just now being confirmed.
Arf