From: X@Xer.com   
      
   Hi all   
      
   "Brian Gaff"  wrote in message   
   news:bovoeo$1iq4rk$3@ID-105134.news.uni-berlin.de...   
   >   
   <>   
      
   > OK, but the fact is it cannot be a stable system, and I still feel that   
   the   
      
   Sorry but there are no such things as stable systems when you are dealing   
   with beasties the size of planetary atmospheres. Do you think Earth's   
   atmosphere is stable? Surprise, surprise, it has changed its composition so   
   many times by such great degrees in the last 300 million years that it left   
   fossil evidence (like piles of dead creatures and plants) thereof.   
      
   > technology to make a breathable atmosphere fast enough to outweigh the   
   > losses is jut  not possible, at least not if you need to have a stable   
      
   No one who has seriously studied Mars or terraforming is talking about   
   making the Martian atmosphere breathable without technological aids in the   
   foresee-able future. It will take too long, no matter what you do (unless   
   you're talking magic Van-Neunmann (sp?) machines and even then it takes   
   awhile). The real goal is to provide enough atmosphere to warm up the planet   
   and protect the surface from UV and cosmic radiation and to get an   
   eco-system.   
      
   And this denser atmosphere once established will last without much   
   maintenance for anything between hundreds of millions to a billion years.   
   That is way longer than humanity needs to bother thinking about. A thousand   
   years ago our ancestors were cleaving each other in two with axes. A million   
   years ago our ancestors were picking flees off each others backs. A hundred   
   million years ago our ancestors were snacks for the few dinosaurs who could   
   bother to hunt out the miserable little rodent sized parasites that we are.   
   Five hundred million years ago Earth was a sterile ball of cooling rock. If   
   we can get an atmosphere that has a half-life (50% will remain) after a   
   hundred million years then we've done immeasurably better than we needed to.   
   Our descendants, their descendants, and people who will not even remember   
   than Mars was once a lifeless world will have plenty of atmosphere to   
   protect them for millenia to come.   
      
   > ecology. It may depend on if there is water in a sufficient quantity   
   > somewhere that could be eventually liberated safely on the surface.   
      
   Mars already experiences temperatures (briefly and in rare, equatorial   
   zones) where liquid water exists. Once you start raising the temperature   
   with extra green houses gases (which BTW carbon dioxide is a lousy example   
   of, methane much better, industrial CFCS, even better, Martyn Fogg mentioned   
   another catogory of semi-exotic gases whose names I can not now remember   
   that make all other look quite silly though). Once you've got more liquid   
   water you've got more water vapor (green house gas), and new erosion.   
   Erosion puts additional CO2 back into the atmosphere, driving the cycle even   
   faster. Once you've got liquid water, you can also start doing swell things   
   like getting stands of arctic pines growing out in the permafrost. Once they   
   get going the planet is yours for the taking.   
      
   >   
   > Brian   
   >   
   > --   
   > Brian Gaff....   
   >  graphics are great, but the blind can't hear them   
   > Email: briang1@blueyonder.co.uk   
   >   
   ____________________________________________________________________________   
   > <>   
      
   Regards   
   Frank   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)