XPost: sci.space.policy   
   From: bondage@frontiernet.net   
      
   Craig Fink wrote:   
   >   
   > On Tue, 18 Jan 2005 05:15:00 +0000, Henry Spencer wrote:   
   >   
   > > In article , Craig Fink   
   > >  wrote:   
   > >>Just wondering how big the tides on Titan might be? Maybe they're huge?   
   > >   
   > > Yes and no.  Your intuition is correct that Saturn will raise very large   
   > > tidal bulges in Titan.  *However*, Titan is tide-locked to Saturn, so   
   > > those big bulges don't move around much -- the moon is basically just a   
   > > little bit egg-shaped all the time.   
   > >   
   > > Titan's slightly elliptical orbit will cause the bulges to move around a   
   > > little, and also to change height slightly as the distance from Saturn   
   > > changes.  So they aren't *quite* completely fixed, but fairly close to   
   > > it.   
   > >   
   > > (This *was* used to put some constraints on the possibility of a global   
   > > ocean on Titan:  tidal dissipation effects would have circularized   
   > > Titan's orbit long ago if it had a shallow global ocean, especially one   
   > > obstructed by islands and continents like Earth's.  Titan oceans had to   
   > > be either fairly deep and essentially land-free, or broken up into   
   > > multiple unconnected regional oceans.)   
   >   
   > Yes, but it's not always tide-locked. Anytime that there is a significant   
   > impact, one that might cause a large crater, it changes the velocity of   
   > Titan's orbit (changing it's orbital period) and changes Titan's angular   
   > momentum (rotation rate). Now the tidal bulge is going to start moving   
   > very slowly round and round Titan until all the energy is used up and it   
   > becomes tide-locked again. Then the next impact, and the next.   
      
      
      But when was the last time a signifigant impact might've happened?   
   Maybe on the same scale as Earth now, I suspect.   
      
      
   > If the tidal bulge is really large, it could be like an "ocean tide" where   
   > the entire ocean goes round and round the moon very slowly. A new form of   
   > erosion, with "tidal rivers".   
   >   
   > Still wondering exactly how big Titan's tidal bulge is?   
   >   
   > Craig Fink   
      
      
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