...And where does the water come from in the first place? Ice I’m sure, but where does the ice come from? You have to have water, before ice can form.
Very interesting.
Where the water came from is a great question.
When the moon was warmer after it was formed, and maybe from bombardments of comets & asteroids. But because it’s only about 300 miles in diameter. I wouldn’t think there would be enough gravity to hold back evaporating water vapour.
So maybe it was never liquid on the surface, but the stress of Jupitor’s immense gravity and that from the other huge moons may be heating the moon under the ice causing liquid water.
I can only guess, based upon what I read, and it’s all speculation at this point.
Just have to wait for more explorations if zero doesn’t kill NASA, that is.