Re: can a moon sustain life in a solar system?

From: Patrick Spinler (pspinler_at_yahoo.com)
Date: 01/25/05 

Date: Tue, 25 Jan 2005 11:33:31 -0600

Mike Williams wrote:
> Wasn't it jcamjr who wrote:
>
>>An interesting side thought has to do with the viability of an earth
>>type planet in orbit of a red dwarf for the planet to recieve enough
>>energy for water to remain in a liquid state it would have to orbit so
>>close to its star as to be tidaly locked with one side to the star and
>>the other always in darkness this would be a poor place to hope to find
>>a viable biosphere However what if instead this world was in fact a
>>moon in orbit of a giant planet within the stars lifezone? this would
>>seem to solve the tidal lock problem. Someone tell me what I'm missing
>>here Im sure theres something wrong with this scenerio
>
>
> One other thing that the moon dwellers might have some concerns about is
> the strength of the tides from the red dwarf. The moon could be tidally
> locked to the gas giant, so tides raised by the giant planet would be
> fixed and wouldn't be a problem for the inhabitants.
>
> On Earth, the solar tides are about a third of the lunar tides and just
> cause the variations between spring and neap tides. In order to get into
> a habitable zone around a red dwarf we might move about 100 times closer
> to a star that's a tenth the mass of our Sun. Tidal force is (to a first
> order approximation (and at this extreme second order effects might be
> significant)) tidal force is proportional to mass and inversely
> proportional to the cube of the distance. So the tides from the red
> dwarf could be 33,000 times stronger than our lunar tides.
>

Please forgive my uneducated question, but we're hypothosizing a gas
giant with an earth like moon in a close orbit to a red dwarf, right ?
In order to be in the habital zone, this would need to be a relatively
close orbit to the star, right?

Would not the gas giant therefore show noticable tidal bulges? And
wouldn't these lock to the star? How large would they be, and would
they effect the earth like moon's orbit or tides?

-- Pat

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