Re: large masses on Phobos, Diemos

From: Dr John Stockton (spam_at_merlyn.demon.co.uk)
Date: 03/11/05 

Date: Fri, 11 Mar 2005 19:18:33 +0000

JRS: In article <1110151986.998197.79330@f14g2000cwb.googlegroups.com>,
dated Sun, 6 Mar 2005 15:33:07, seen in news:sci.space.tech,
gigantino@speakeasy.net posted :
>I am wondering how to find the pull of Mar's gravity at the Martian
>Moon's orbits. The pull of Phobos' own gravity varies between 8.4-1.9
>mm/s² (http://www.answers.com/topic/phobos-moon) - but what effect
>does Mars exert at 9200km altitude?
>
>The problem I'm trying to figure out is if a mass of liquid/slush water
>was domed inside Stickney Crater, would it settle against the moon or
>the top of the dome? Stickney is roughly 10km, the dome would be
>built/grown around the lip. Stickney always faces Mars, IIRC, so there
>should be a fairly even pull. Any guesses at sloshing and wave effects
>would be appreciated.

All natural satellites of non-trivial size, including those of Mars, are
outside the applicable Roche Limit. Rings are inside the Roche Limit.
Read about Roche.

Since Phobos is only a little outside the limit, apparent gravity at the
inward and outward points should be substantially less than it is half-
way between them. If Phobos were rotating with respect to Mars, it
would show large ocean-tides, if it had oceans.
 

(Re-post, as first post, sent on the 8th, not seen) 

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