Hi Guys

Well what can I say?

...are both dead and I'm not.

[Point]

They meant well, but their writings on the subject were pretty much speculation. The last decade has seen a lot of work go into this sort of question and the answers are pretty discouraging.

[True. Jupiter is a LOT hotter than they imagined. They were writing on the basis of a hydrogen greenhouse warming up a deep layer of water that rested on metallic hydrogen. Jupiter is probably too turbulent to allow that sort of segregation - though Ben Bova still writes as though it isn't so...]

The way in which gas giants MAY be associated with life is rather different. Now that we have discovered a host of close-in Jupiters round other stars, the old models that gas giants HAD to be out in the cold outer regions of a solar system have died.

[Hallelujah!]

Jovians are now known to lie within the habitable zone, and a Moon of such a Jovian would also be stable for liquid water (if large enough to retain the vapour over geologic time).

[About as big as Mars, if tidal forces keep its magnetic field and geocycles pumped up over geotime]

Imagine Europa with liquid water from surface to depth, or Callisto and Gannymede with oceans and land. Here is a niche for life-as-we-know-it associated with gas giants.

[Europa, yes, but the oceans on the two big boys would be DEEP. Still, we don't know what the scaling ratio between satellite & primary is yet. My guess is that it's nonlinear and we might see Mars sized rocky moons around ~ 3 Jupiter mass planets.]

(Apologies to IA and CS, both of whom I admire and would have loved to have met, but time and science marches on)

[Indeed. I think deep oceans on Jovian planets might still be a go, but definitely wouldn't be life-as-we-know-it in them.]

Adam