[Traveller_TNE] The Gas Giant in the Habitable Zone Thread

--- In , "paulsnowuk" <P.A.Snow@...> wrote:
>
> --- In , "Allen" <justacarpenter@>
> wrote:
> >
> > The more we search, the closer we get. Now we have found a star
> system
> > with a Gas Giant in the habitable zone. Can life be supported on a
> gas
> > giant moon? we might never know in our lifetimes
> > http://www.sciencedaily.com/releases/2007/11/071106133058.htm
> >
>
> Actually, I thought this was rather interesting too.
>
> http://www.nytimes.com/2007/11/06/science/space/07planetweb.html?
> _r=1&oref=slogin
>
> More chances of a goldilocks zone? Any real astrophycisits here to give
> us a briefing on the current thinking?
>
> Paulsnow
>
--- In , "Evil Dr Ganymede"
<evil_dr_ganymede@...> wrote:
>
> --- In , Bo <lorgryt@> wrote:
> > Can life be supported on a gas giant moon? Of course it can, and the
> > idea of a habitable zone is pretty much obsolete at this point.
> > Life exists in very different types of environs than we ever thought
> > it could.
>
> True, but that doesn't make the idea of a habitable zone obsolete. The
> fact remains that there's still a band around a star at a certain
> distance in which the temperatures are appropriate for organic life
> (in fact it's defined (according to Kastings 1993, Icarus, v101, p108)
> roughly speaking the definition is as follows:
>
> Inner boundary: Maximum distance from the star at which a runaway
> greenhouse effect would lead to the evaporation of all surface water.
>
> Outer boundary: Maximum distance at which a cloud-free CO2 atmosphere
> could maintain a surface temperature of 273 K.
>
> In practice that actually varies from star to star (it's not a
> constant times the root of the luminosity though as described in
> various Traveller books - details are in Jones/Sleep/Underwood 2003,
> ApJ, v649, p1010-1019) but for a G2 V star like the sun it's between
> 0.82 AU and 1.64 AU.
>
> That's not to say it can't form or survive elsewhere (underground or
> under ice where there is water, in cometary interiors, etc), but the
> habitable zone is still a valid concept.
>
>
> [quote]But, remember, life is just a single cell looking for love. And
> I believe that can and does exist around Jupiter, if not in its
> atmosphere.[/quote]
>
> If there's an ocean under the ice on Europa and Ganymede and Callisto
> (which seems likely) then I'd agree. I don't think we know enough to
> be certain quite yet - we don't even know how life forms to start
> with. Maybe it always forms whenever conditions are right, maybe it
> forms only very rarely even if conditions allow it.
>