Re: What I've never understood about this comets and water business is...
Related point: don't terrestrial lavas have fairly quantities of water and other volatiles, up to several percent? As I understand it, water significantly affects the violence of a volcanic eruption, with more water in the lava causing more violent explosions, and water is the primary component of volcanic gases.
That implies (to me) that water can survive and be trapped in very hot, forming planetismals (sp).
