From: rstokes1@san.rr.com   
      
   I have read that Earth underwent complete freezing of its oceans several   
   hundred million years ago - the sea ice at the equator was a mile thick, and   
   equatorial daytime temperatures were below -50 C.  This was due to the fact   
   that if ice forms below 35th latitude, enough sunlight is reflected to space   
   that runaway cooling occurs, since at Earth's orbital distance the   
   temperature of a non-greenhouse body averages about -60 C.   
      
   Earth only escaped from that condition because volcanoes on continents   
   released CO2 linto the atmosphere and the Earth was so cold there was no   
   rainfall to wash it out. After 20 million years there was enough CO2 to   
   raise the temperature and melt the ice - and then caused a runaway   
   greenhouse for a few thousand years with temperatures at the equator of +50   
   C.   
      
   So if a terrestrial planet has more water than Earth, such that no   
   continents appear above sea level, will that planet be destined to end up   
   sooner or later as a permanent iceworld, or is there some other method of   
   escape?   
      
   If the planet is close enough to it's sun that water would not freeze in the   
   absence of greenhouse gases, would it inevitably end up like Venus?   
      
   In summary, can a waterworld even exist?   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)