[X] My Assistant

[dvandorn]

I think that, at this point in time, after what we've seen at both Jupiter and Saturn, we can make the following generic statements:

Rocky bodies with no atmosphere: Predominated by craters.

Solid icy bodies with no atmosphere: Predominated by craters and then cracks (i.e., tectonic formations).

Partially solid (i.e., with liquid water underneath a solid ice crust) icy bodies with no atmosphere: Predominated by cracks and then craters.

The less solid an icy body is, the fewer craters we see and the more cracks we see. But at no point do we seem to lose the tectonic formations -- if it's icy, it's cracked.

So, we seem to have a rough rule of thumb in terms of the potential for subsurface oceans -- the higher the ratio of cracks to craters, the greater the chance of an ocean.

-the other Doug