[X] My Assistant

[nprev]

The Cassini website as well as the mass media is announcing a 'new' hypothesis on internal heating. The article also states that complex (presumably) organic molecules observed in the plumes imply an active heat source. Anybody have more details?

I still can't figure out exactly how Enceladus might have been particularly enriched in Al-26 with respect to the other icy moons, other than its proximity to Saturn during its formation...

[edstrick]

"....The one thing that really surprised me is the estimate of the total mass loss over the age of the Saturn system. A fifth of an Enceladus mass! One would think that this should have noticeably distorted the shape of the moon...."

Point one: That's a pure assumption that the current rate of mass loss can be extrapolated back at a constant mass loss rate. There is a clear problem that the tidal heating calculated for the resonances Enceladus is in and could be in just doesn't add up to the current activity and heat flux.

Point 2... Enceladus is like silly-putty inside... Look at those fissure-fractured craters where the crater walls deflect the crack pattern and the crater floor is domed up with more fissures. There's a brittle shell of cold ice, and a soft layer underneath, the depth to the soft layer depending on the local heat flow. In some areas, convecting ice makes the furrowed looping texture where it's laterally deformed the crust, in others, most unusually compared with Ganymede and Europa, etc, the crust over the soft ice has just evened out isostatically, fracturing as it went.